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Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Retinal Diseases: Age-Related Macular Degeneration and Retinitis Pigmentosa  

NLE Websites -- All DOE Office Websites (Extended Search)

Retinal Diseases: Age-Related Macular Degeneration and Retinitis Pigmentosa Retinal Diseases: Age-Related Macular Degeneration and Retinitis Pigmentosa Age-related macular degeneration (AMD) is an eye disease primarily affecting the central vision regions in people age 60 and older. According to the Macular Degeneration Research Fund, a case of AMD is diagnosed in the United States every 3 minutes. Each year, 1.2 million of the estimated 12 million people with AMD will suffer severe vision loss. Patients with AMD have dark areas in their vision caused by fluid leakage or bleeding in the macula, the center of the retina that produces the sharpest vision. The brain initially compensates for these dark patches. Early cellular dysfunction or spotting in the macula may go undetected until the disease is in advanced stages.

2

Phase I clinical trial results of verteporfin enhanced feeder vessel therapy in subfoveal choroidal neovascularisation in age related macular degeneration.  

E-Print Network (OSTI)

including lesions with occult with no classic choroidalPDT for minimally classic or occult with no classic CNV; andboth in classic and occult choroidal neovascularization.

Kozak, I; Cheng, L; Cochran, D E; Freeman, W R

2006-01-01T23:59:59.000Z

3

Accident sequence precursor events with age-related contributors  

SciTech Connect

The Accident Sequence Precursor (ASP) Program at ORNL analyzed about 14.000 Licensee Event Reports (LERs) filed by US nuclear power plants 1987--1993. There were 193 events identified as precursors to potential severe core accident sequences. These are reported in G/CR-4674. Volumes 7 through 20. Under the NRC Nuclear Plant Aging Research program, the authors evaluated these events to determine the extent to which component aging played a role. Events were selected that involved age-related equipment degradation that initiated an event or contributed to an event sequence. For the 7-year period, ORNL identified 36 events that involved aging degradation as a contributor to an ASP event. Except for 1992, the percentage of age-related events within the total number of ASP events over the 7-year period ({approximately}19%) appears fairly consistent up to 1991. No correlation between plant ape and number of precursor events was found. A summary list of the age-related events is presented in the report.

Murphy, G.A.; Kohn, W.E.

1995-12-31T23:59:59.000Z

4

Candidate genes for chromosomes 6 and 10 quantitative trait loci for age-related retinal degeneration in mice  

E-Print Network (OSTI)

), complement factor B (CFB), and complement component 2 (C2), Chemokine (C-X3-C motif) receptor 1 (CX3CR1), Age to permanent exposure to reactive oxygen species generated by the absorption of light. Genes involved in gene expression should reflect an adjustment of blood flow for the oxygen requirement of the retina

Dahlquist, Kam D.

5

Double Degenerate Binary Systems  

Science Conference Proceedings (OSTI)

In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

Yakut, K. [University of Ege, Department of Astronomy and Space Sciences, 35100-Izmir (Turkey)

2011-09-21T23:59:59.000Z

6

Use Of Green Porphyrinsto Treat Neovasculature In The Eyes  

DOE Patents (OSTI)

Photodynamic therapy of conditions of the eye characterized by unwanted neovasculature, such as age-related macular degeneration, is effective using green porphyrins as photoactive agents, preferably as liposomal compositions.

Levy, Julia (Vancouver, CA); Miller, Joan W. (Boston, MA); Gradoudas, Evangelos S. (Boston, MA); Hasan, Tayyaba (Arlington, MA); Schmidt-Erfurth, Ursula (Luebeck, DE)

1998-08-25T23:59:59.000Z

7

On Degenerate Planar Hopf Bifurcations  

E-Print Network (OSTI)

Our concern is the study of degenerate Hopf bifurcation of smooth planar dynamical systems near isolated singular points. To do so, we propose to split up the definition of degeneracy into two types. Degeneracy of first kind shall means that no limit cycle surrounding the steady state can emerge after or before the critical point, with the possible emergence of limit cycles surrounding the point at infinity. Degeneracy of second kind shall means that either several limit cycles or semistable cycles as a limiting case, emerge surrounding the steady state super or subcritically. In degenerate bifurcation of second kind we also show that the radius of the emerging cycle tends to zero with an "anomalous" order as the bifurcation parameter tends to the critical value. Finally, we give a sufficient condition for degenerate bifurcations of second kind up to 6-jet-equivalence, and show some "typical" forms for degenerate bifurcations.

Mariano Rodriguez Ricard

2009-12-15T23:59:59.000Z

8

Degenerate Parabolic Stochastic Partial Differential Equations  

E-Print Network (OSTI)

Degenerate Parabolic Stochastic Partial Differential Equations Martina Hofmanov´a Abstract. We study the Cauchy problem for a scalar semilinear degenerate parabolic partial differential equation the notion of kinetic solution which is well suited for degenerate parabolic problems and supplies a good

Paris-Sud XI, Université de

9

Age-related changes in receptor-mediated phosphoinositide hydrolysis in various regions of rat brain  

SciTech Connect

The effects of age on cholinergic markers and receptor-stimulated phosphoinositide hydrolysis was examined in the frontal cortex and striatum of male Fischer-344 rats. Choline acetyltransferase activity was decreased 27% in the striatum of aged rats compared to young controls. Muscarinic receptor density as measured by ({sup 3}H)-quinuclidinyl benzilate binding showed a similar 26% decrease in the striatum of aged rats. Phosphoinositide hydrolysis was measured by the release of inositol phosphate (IP) from tissue slices prelabeled with ({sup 3}H)myoinositol in response to carbachol, norepinephrine, and quisqualate. In the cortex, stimulated IP release was significantly greater in slices from aged rats compared to young rats for all three agonists. In contrast, stimulated IP release was significantly decreased in striatal slices from aged rats compared to young for all three agonists. These data indicate a differential effect of age on agonist-stimulated phosphoinositide hydrolysis in the cortex and striatum. The decreased responsiveness in the latter area may result from the age-related loss of postsynaptic receptors.

Mundy, W.; Tandon, P.; Tilson, H. (Research Triangle Park, NC (United States)); Ali, S. (National Center for Toxicological Research, Jefferson, AR (United States))

1991-01-01T23:59:59.000Z

10

Carotenoids & Retinoids; Molecular Aspects and Health IssuesChapter 7 Macular Carotenoids in Eye Health  

Science Conference Proceedings (OSTI)

Carotenoids & Retinoids; Molecular Aspects and Health Issues Chapter 7 Macular Carotenoids in Eye Health Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf...

11

Lifelong voluntary exercise in the mouse prevents age-related alterations in gene expression in the heart  

E-Print Network (OSTI)

in the heart A. M. BRONIKOWSKI,1,7 P. A. CARTER,2 T. J. MORGAN,2 T. GARLAND, JR.,3 N. UNG,1 T. D. PUGH,4 R voluntary exercise in the mouse prevents age-related alterations in gene expression in the heart. Physiol changes that normally occur in the aging heart. Male mice (Mus domesticus) were sampled from the 16th

Bronikowski, Anne

12

A discrete BGK approximation for strongly degenerate parabolic problems  

E-Print Network (OSTI)

A discrete BGK approximation for strongly degenerate parabolic problems with boundary conditions F strongly degenerate hyperbolic--parabolic equations with initial boundary condition. We prove a priori -- strongly degenerate parabolic equations -- singular perturbation problems -- BGK models 1 Introduction

13

Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales  

SciTech Connect

The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bones toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by plastic deformation at higher structural levels, which occurs by the process of microcracking.

Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.

2011-08-10T23:59:59.000Z

14

Ion acoustic shock waves in degenerate plasmas  

SciTech Connect

Korteweg de Vries Burgers equation for negative ion degenerate dissipative plasma has been derived using reductive perturbation technique. The quantum hydrodynamic model is used to study the quantum ion acoustic shock waves. The effects of different parameters on quantum ion acoustic shock waves are studied. It is found that quantum parameter, electrons Fermi temperature, temperature of positive and negative ions, mass ratio of positive to negative ions, viscosity, and density ratio have significant impact on the shock wave structure in negative ion degenerate plasma.

Akhtar, N. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Hussain, S. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Department of Physics and Applied Mathematics, PIEAS, Nilore, Islamabad 44000 Pakistan (Pakistan)

2011-07-15T23:59:59.000Z

15

Aging-Related Changes in Cardiac Sympathetic Function in Humans, Assessed by 6- 18 F-Fluorodopamine PET Scanning  

E-Print Network (OSTI)

Sympathetic nerves play key roles in cardiac physiology and aging-related cardiovascular diseases. This study examined the effects of normal human aging on cardiac sympathetic innervation and function, including the neuronal uptake of catecholamines (uptake 1) via the cell membrane norepinephrine transporter. Methods: Thirty-three healthy volunteers, 17 under 40 and 16 over 50 y old, underwent thoracic PET scanning after injection of the sympathoneural imaging agent 6-18F-fluorodo pamine. Myocardial perfusion was estimated by 13NH3 scanning, and arterial blood was sampled for levels of 6-18F-fluoro dopamine and 6-18F-fluorodopaminederived radioactivity. Results: The older group had more myocardial 6-18F-fluorodo paminederived radioactivity than did the younger group. Myocardial perfusion was also greater in the older group, and arterial blood levels of 6-18F-fluorodopamine were also higher. After

Sheng-ting Li

2002-01-01T23:59:59.000Z

16

On multimode pulsations of degenerate stellar models  

Science Conference Proceedings (OSTI)

Nonlinear dissipative radial oscillations of partially and completely degenerate stellar models have been studied. The general mathematical framework for the study of interaction between various radial modes of oscillation has been presented. The dynamical tools, e.g., Poincare surface of section and the spectrum of Liapunov exponents, have been used to investigate the nature of pulsation in the phase space. For simplicity, numerical computations have been made to study the interaction of only the first three modes, including the fundamental mode for both partially and completely degenerate stellar masses. For these models, with varying degrees of central degeneracy, the possible occurrence of quasi-periodic motions with as many as three irrationally related frequencies has been established in the dissipative regime. 56 refs.

Das, M.K.; Singh, H.P.; Tandon, J.N. (Delhi Univ. (India))

1989-11-01T23:59:59.000Z

17

NEUTRINO PROCESSES IN PARTIALLY DEGENERATE NEUTRON MATTER  

Science Conference Proceedings (OSTI)

We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.

Bacca, S.; Hally, K. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Liebendoerfer, M.; Perego, A. [Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel (Switzerland); Pethick, C. J. [Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark); Schwenk, A. [ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

2012-10-10T23:59:59.000Z

18

Almost Degenerate Neutrinos with Maximal Mixing  

E-Print Network (OSTI)

If the upper limit on the effective (Majorana) neutrino mass from neutrinoless double beta decay experiments is confirmed to be much less than an electron-volt, then one way to reconcile it with the degenerate neutrino mass pattern suggested recently to explain the observed deficit of solar and atmospheric neutrinos as well as neutrinos as HDM is to postulate that there be maximal mixing among the three light (or two) neutrinos. This suggestion is advanced in this paper and is analysed.

R. N. Mohapatra; S. Nussinov

1994-11-11T23:59:59.000Z

19

Effect of trapping in degenerate quantum plasmas  

SciTech Connect

In the present work we consider the effect of trapping as a microscopic process in a plasma consisting of quantum electrons and nondegenerate ions. The formation of solitary structures is investigated in two cases: first when the electrons are fully degenerate and second when small temperature effects are taken into account. It is seen that not only rarefactive but coupled rarefactive and compressive solitons are obtained under different temperature conditions.

Shah, H. A.; Qureshi, M. N. S. [Department of Physics, GC University, Lahore 54000 (Pakistan); Tsintsadze, N. [Department of Physics, GC University, Lahore 54000 (Pakistan); Salam Chair, GC University, Lahore 54000 (Pakistan)

2010-03-15T23:59:59.000Z

20

Relativistic Bernstein waves in a degenerate plasma  

SciTech Connect

Bernstein mode for a relativistic degenerate electron plasma is investigated. Using relativistic Vlasov-Maxwell equations, a general expression for the conductivity tensor is derived and then employing Fermi-Dirac distribution function a generalized dispersion relation for the Bernstein mode is obtained. Two limiting cases, i.e., non-relativistic and ultra-relativistic are discussed. The dispersion relations obtained are also graphically presented for some specific values of the parameters depicting how the propagation characteristics of Bernstein waves as well as the Upper Hybrid oscillations are modified with the increase in plasma number density.

Ali, Muddasir; Hussain, Azhar [Department of Physics, G.C. University, Lahore 54000 (Pakistan); Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan)

2011-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Landau Diamagnetism of Degenerate Collisional Plasma  

E-Print Network (OSTI)

For the first time the kinetic description of Landau diamagnetism for degenerate collisional plasma is given. The correct expression for transverse electric conductivity of the quantum plasma, found by authors (see arXiv:1002.1017 [math-ph] 4 Feb 2010) is used. In work S. Dattagupta, A.M. Jayannavar and N. Kumar [Current science, V. 80, No. 7, 10 April, 2001] was discussed the important problem of dissipation (collisions) influence on Landau diamagnetism. The analysis of this problem is given with the use of exact expression for transverse conductivity of quantum plasma.

A. V. Latyshev; A. A. Yushkanov

2010-07-05T23:59:59.000Z

22

The many-body Green function of degenerate systems  

E-Print Network (OSTI)

A rigorous non perturbative adiabatic approximation of the evolution operator in the many-body physics of degenerate systems is derived. This approximation is used to solve the long-standing problem of the choice of the initial states of H0 leading to eigenstates of H0+V for degenerate systems. These initial states are eigenstates of P0 V P0, where P0 is the projection onto a degenerate eigenspace of H0. This result is used to give the proper definition of the Green function, the statistical Green function and the non-equilibrium Green function of degenerate systems. The convergence of these Green functions is established.

Christian Brouder; Gianluca Panati; Gabriel Stoltz

2009-06-11T23:59:59.000Z

23

Weibel instabilities in a completely degenerate electron Fermi gas  

SciTech Connect

Weibel instability in a degenerate Fermi plasma is studied. A new type of quantum Weibel instabilities is disclosed. In particular, a novel oscillatory Weibel instability is found and its growth rate is obtained. A transverse zero sound in a quantum degenerate electron gas, which has no counterpart in the classical consideration, is revealed.

Tsintsadze, Levan N. [Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

2009-09-15T23:59:59.000Z

24

Crystallization and collapse in relativistically degenerate matter  

SciTech Connect

In this paper, it is shown that a mass density limit exists beyond which the relativistically degenerate matter would crystallize. The mass density limit, found here, is quite analogous to the mass limit predicted by Chandrasekhar for a type of compact stars called white dwarfs (M{sub Ch} Asymptotically-Equal-To 1.43 Solar Mass). In this study, the old problem of white dwarf core collapse, which has been previously investigated by Chandrasekhar using hydrostatic stability criteria, is revisited in the framework of the quantum hydrodynamics model by inspection of the charge screening at atomic scales in the relativistic degeneracy plasma regime taking into account the relativistic Fermi-Dirac statistics and electron interaction features such as the quantum statistical pressure, Coulomb attraction, electron exchange-correlation, and quantum recoil effects. It is revealed that the existence of ion correlation and crystallization of matter in the relativistically degenerate plasma puts a critical mass density limit on white dwarf core region. It is shown that a white dwarf star with a core mass density beyond this critical limit can undergo the spontaneous core collapse (SCC). The SCC phenomenon, which is dominantly caused by the electron quantum recoil effect (interference and localization of the electron wave function), leads to a new exotic state of matter. In such exotic state, the relativistic electron degeneracy can lead the white dwarf crystallized core to undergo the nuclear fusion and an ultimate supernova by means of the volume reduction (due to the enhanced compressibility) and huge energy release (due to the increase in cohesive energy), under the stars huge inward gravitational pressure. Moreover, it is found that the SCC phenomenon is significantly affected by the core composition (it is more probable for heavier plasmas). The critical mass density found here is consistent with the values calculated for core density of typical white dwarf stars.

Akbari-Moghanjoughi, M. [International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, D-44780 Bochum, Germany and Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 51745-406 Tabriz (Iran, Islamic Republic of)

2013-04-15T23:59:59.000Z

25

DEGENERATE-PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS WITH UNBOUNDED COEFFICIENTS, MARTINGALE PROBLEMS, AND A  

E-Print Network (OSTI)

DEGENERATE-PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS WITH UNBOUNDED COEFFICIENTS, MARTINGALE four intertwined problems, motivated by mathematical finance, concerning degenerate-parabolic partial differential operators and degenerate diffusion processes. First, we consider a parabolic partial differential

26

Materials Reliability Program: PWR Internals Age-Related Material Properties, Degradation Mechanisms, Models, and Basis Data - State of Knowledge (MRP-211)  

Science Conference Proceedings (OSTI)

The purpose of this report is to summarize the current state-of-knowledge of neutron irradiation-induced property changes in austenitic stainless steels, principally solution-annealed Type 304 and 304L materials, cold-worked and solution-annealed Type 316 and 316L materials, and Type 308 weld metal. The age-related degradation models were evaluated by an expert panel assembled by EPRI and the Reactor Internals Focus Group (RI-FG). This panel endorsed models to be used in functionality evaluations and sug...

2007-12-19T23:59:59.000Z

27

Transversal electric conductivity of quantum non-degenerate collisional plasmas  

E-Print Network (OSTI)

Formulas for calculation of transversal dielectric function and transversal electric conductivity in quantum non-degenerate collisional plasmas under arbitrary degree of degeneracy of the electron gas are received. The Wigner-Vlasov-Boltzmann kinetic equation with collision integral in BGK (Bhatnagar, Gross and Krook) form in coordinate space is used. Various special cases are investigated

Latyshev, A V

2012-01-01T23:59:59.000Z

28

Transversal electric conductivity of quantum non-degenerate collisional plasmas  

E-Print Network (OSTI)

Formulas for calculation of transversal dielectric function and transversal electric conductivity in quantum non-degenerate collisional plasmas under arbitrary degree of degeneracy of the electron gas are received. The Wigner-Vlasov-Boltzmann kinetic equation with collision integral in BGK (Bhatnagar, Gross and Krook) form in coordinate space is used. Various special cases are investigated

A. V. Latyshev; A. A. Yushkanov

2012-05-29T23:59:59.000Z

29

Exact null controllability of degenerate evolution equations with scalar control  

SciTech Connect

Necessary and sufficient conditions for the exact null controllability of a degenerate linear evolution equation with scalar control are obtained. These general results are used to examine the exact null controllability of the Dzektser equation in the theory of seepage. Bibliography: 13 titles.

Fedorov, Vladimir E; Shklyar, Benzion

2012-12-31T23:59:59.000Z

30

Degenerate flag varieties: moment graphs and Schrder numbers  

Science Conference Proceedings (OSTI)

We study geometric and combinatorial properties of the degenerate flag varieties of type A. These varieties are acted upon by the automorphism group of a certain representation of a type A quiver, containing a maximal torus T. Using the group ... Keywords: Flag varieties, Moment graphs, Quiver Grassmannians, Schrder numbers

Giovanni Cerulli Irelli; Evgeny Feigin; Markus Reineke

2013-08-01T23:59:59.000Z

31

Linear and nonlinear degenerate boundary value problems in Besov spaces  

Science Conference Proceedings (OSTI)

The boundary value problems for linear and nonlinear degenerate differential-operator equations in Banach-valued Besov spaces are studied. Several conditions for the separability of linear elliptic problems are given. Moreover, the positivity and the ... Keywords: Banach-valued Besov spaces, Boundary value problems, Differential-operator equations, Interpolation of Banach spaces, Operator-valued multipliers

Veli B. Shakhmurov; Ravi P. Agarwal

2009-03-01T23:59:59.000Z

32

Di usive Kinetic Explicit Schemes for Nonlinear Degenerate Parabolic Systems  

E-Print Network (OSTI)

Di#11;usive Kinetic Explicit Schemes for Nonlinear Degenerate Parabolic Systems #3; D. Aregba parabolic systems. These schemes are based on discrete BGK models where both characteristic velocities. Evje and K.H. Karlsen [15] and of M. Espedal and K.H. Karlsen [14]. For the theory of general parabolic

33

Exploring the origin of degenerate doublet bands in $^{106}$Ag  

E-Print Network (OSTI)

The electromagnetic transition probabilities of the excited levels for the two nearly degenerate bands of $^{106}$Ag have been measured using the Doppler Shift Attenuation Method. A comparison with the calculated values using triaxial projected shell model approach indicates that these bands originate from two different quasi-particle configurations but constructed from the same mean-field deformation.

N. Rather; P. Datta; S. Chattopadhyay; S. Roy; S. Rajbanshi; A. Gowsami; G. H. Bhat; J. A. Sheikh; R. Palit; S. Pal; S. Saha; J. Sethi; S. Biswas; P. Singh; H. C. Jain

2013-10-29T23:59:59.000Z

34

Proc. WABI-03, to appear. Selecting Degenerate Multiplex PCR Primers  

E-Print Network (OSTI)

Proc. WABI-03, to appear. Selecting Degenerate Multiplex PCR Primers Richard Souvenir ¡ , Jeremy of multiplex PCR (MP-PCR) to amplify the regions around the SNP. Multiplex PCR is a variation of PCR where multiple DNA fragments are replicated simultaneously. MP-PCR, like all PCR variations, makes use of oligonu

Zhang, Weixiong

35

Current-Drive Efficiency in a Degenerate Plasma  

DOE Green Energy (OSTI)

a degenerate plasma, the rates of electron processes are much smaller than the classical model would predict, affecting the efficiencies of current generation by external non-inductive means, such as by electromagnetic radiation or intense ion beams. For electron-based mechanisms, the current-drive efficiency is higher than the classical prediction by more than a factor of 6 in a degenerate hydrogen plasma, mainly because the electron-electron collisions do not quickly slow down fast electrons. Moreover, electrons much faster than thermal speeds are more readily excited without exciting thermal electrons. In ion-based mechanisms of current drive, the efficiency is likewise enhanced due to the degeneracy effects, since the electron stopping power on slow ion beams is significantly reduced.

S. Son and N.J. Fisch

2005-11-01T23:59:59.000Z

36

Magnetic susceptibility and Landau diamagnetism of quantum collisional degenerate plasmas  

E-Print Network (OSTI)

With the use of correct expression of the electric conductivity of quantum collisional degenerate plasmas (A. V. Latyshev and A. A. Yushkanov, Transverse electrical conductivity of a quantum collisional plasma in the Mermin approach, - Theor. and Math. Phys., {\\bf 175}(1): 559-569 (2013)) the kinetic description of a magnetic susceptibility is obtained and the formula for calculation of Landau diamagnetism is deduced.

Latyshev, A V

2013-01-01T23:59:59.000Z

37

Magnetic susceptibility and Landau diamagnetism of quantum collisional degenerate plasmas  

E-Print Network (OSTI)

With the use of correct expression of the electric conductivity of quantum collisional degenerate plasmas (A. V. Latyshev and A. A. Yushkanov, Transverse electrical conductivity of a quantum collisional plasma in the Mermin approach, - Theor. and Math. Phys., {\\bf 175}(1): 559-569 (2013)) the kinetic description of a magnetic susceptibility is obtained and the formula for calculation of Landau diamagnetism is deduced.

A. V. Latyshev; A. A. Yushkanov

2013-05-21T23:59:59.000Z

38

Imploding and exploding shocks in negative ion degenerate plasmas  

SciTech Connect

Imploding and exploding shocks are studied in nonplanar geometries for negative ion degenerate plasma. Deformed Korteweg de Vries Burgers (DKdVB) equation is derived by using reductive perturbation method. Two level finite difference scheme is used for numerical analysis of DKdVB. It is observed that compressive and rarefactive shocks are observed depending on the value of quantum parameter. The effects of temperature, kinematic viscosity, mass ratio of negative to positive ions and quantum parameter on diverging and converging shocks are presented.

Hussain, S.; Akhtar, N. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 (Pakistan); Department of Physics and Applied Mathematics PIEAS, Nilore, Islamabad 44000 (Pakistan)

2011-08-15T23:59:59.000Z

39

Automatic Diabetic Macular Edema Detection in Fundus Images Using Publicly Available Datasets  

SciTech Connect

Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing. Our algorithm is robust to segmentation uncertainties, does not need ground truth at lesion level, and is very fast, generating a diagnosis on an average of 4.4 seconds per image on an 2.6 GHz platform with an unoptimised Matlab implementation.

Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Garg, Seema [University of North Carolina; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

40

Exudate-based diabetic macular edema detection in fundus images using publicly available datasets  

SciTech Connect

Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME through the presence of exudation. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing (e.g., the classifier was trained on an independent dataset and tested on MESSIDOR). Our algorithm obtained an AUC between 0.88 and 0.94 depending on the dataset/features used. Additionally, it does not need ground truth at lesion level to reject false positives and is computationally efficient, as it generates a diagnosis on an average of 4.4 s (9.3 s, considering the optic nerve localization) per image on an 2.6 GHz platform with an unoptimized Matlab implementation.

Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Garg, Seema [University of North Carolina; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Coupled modes in magnetized dense plasma with relativistic-degenerate electrons  

SciTech Connect

Low frequency electrostatic and electromagnetic waves are investigated in ultra-dense quantum magnetoplasma with relativistic-degenerate electron and non-degenerate ion fluids. The dispersion relation is derived for mobile as well as immobile ions by employing hydrodynamic equations for such plasma under the influence of electromagnetic forces and pressure gradient of relativistic-degenerate Fermi gas of electrons. The result shows the coexistence of shear Alfven and ion modes with relativistically modified dispersive properties. The relevance of results to the dense degenerate plasmas of astrophysical origin (for instance, white dwarf stars) is pointed out with brief discussion on ultra-relativistic and non-relativistic limits.

Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan)

2012-01-15T23:59:59.000Z

42

Perpendicular propagating modes for weakly magnetized relativistic degenerate plasma  

SciTech Connect

Using the Vlasov-Maxwell system of equations, the dispersion relations for the perpendicular propagating modes (i.e., X-mode, O-mode, and upper hybrid mode) are derived for a weakly magnetized relativistic degenerate electron plasma. By using the density (n{sub 0}=p{sub F}{sup 3}/3{pi}{sup 2} Planck-Constant-Over-Two-Pi {sup 3}) and the magnetic field values for different relativistic degenerate environments, the propagation characteristics (i.e., cutoff points, resonances, dispersions, and band widths in k-space) of these modes are examined. It is observed that the relativistic effects suppress the effect of ambient magnetic field and therefore the cutoff and resonance points shift towards the lower frequency regime resulting in enhancement of the propagation domain. The dispersion relations of these modes for the non-relativistic limit (p{sub F}{sup 2} Much-Less-Than m{sub 0}{sup 2}c{sup 2}) and the ultra-relativistic limit (p{sub F}{sup 2} Much-Greater-Than m{sub 0}{sup 2}c{sup 2}) are also presented.

Abbas, Gohar; Bashir, M. F. [Salam Chair in Physics, G. C. University Lahore, Punjab 54000 (Pakistan); Department of Physics, G. C. University Lahore, Punjab 54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, G. C. University Lahore, Punjab 54000 (Pakistan)

2012-07-15T23:59:59.000Z

43

Metal-Insulator Transitions in Degenerate Hubbard Models and  

E-Print Network (OSTI)

Mott-Hubbard metal-insulator transitions in N-fold degenerate Hubbard models are studied within the Gutzwiller approximation. For any rational filling with x (integer) electrons per site it is found that metal-insulator transition occurs at a critical correlation energy Uc(N,x) = Uc(N,2N ? x) = ?(N,x)|?(N,x)|, where ? is the band energy per particle for the uncorrelated Fermi-liquid state and ?(N,x) is a geometric factor which increases linearly with x. We propose that the alkali metal doped fullerides AxC60 can be described by a 3-fold degenerate Hubbard model. Using the current estimate of band width and correlation energy this implies that most of AxC60, at integer x, are Mott-Hubbard insulators and A3C60 is a strongly correlated metal. PACS numbers: 71.10.+x,71.30.+h,74.70.W 1 Typeset using REVTEXThe discovery of superconductivity in A3C60 [1] has spurred great interest in alkali metal doped fullerides [2]. Beside A3C60, stable phases such as Rb1C60, Na2C60, K4C60 were

Jian Ping Lu

2008-01-01T23:59:59.000Z

44

Umklapp Lasing with a Quantum Degenerate Fermi Gas  

E-Print Network (OSTI)

We introduce the driven quantum degenerate Fermi gas as a lasing medium in optical cavities. We show that the existence of a Fermi surface fundamentally alters the behavior of the charge-ordering ("self-organization") superradiant transition that occurs when the atoms are driven sufficiently strongly. Resonant Umklapp scattering processes, where the fermions are scattered from one side of the Fermi surface to the other by exchanging photon momenta, lead to Peierls reconstruction of the dynamical cavity band structure at low superradiance threshold. The spectral properties of the cavity light field can be tuned by the Fermi wavevector (the density of the gas) relative to the cavity and pump photon momenta. The cavity spectrum can have broadband features from the fermionic particle-hole continuum as well as frequency ranges with narrow linewidth due to dispersive effects of the Fermi gas.

Francesco Piazza; Philipp Strack

2013-09-11T23:59:59.000Z

45

Quantum degenerate mixtures of strontium and rubidium atoms  

E-Print Network (OSTI)

We report on the realization of quantum degenerate gas mixtures of the alkaline-earth element strontium with the alkali element rubidium. A key ingredient of our scheme is sympathetic cooling of Rb by Sr atoms that are continuously laser cooled on a narrow linewidth transition. This versatile technique allows us to produce ultracold gas mixtures with a phase-space density of up to 0.06 for both elements. By further evaporative cooling we create double Bose-Einstein condensates of 87Rb with either 88Sr or 84Sr, reaching more than 10^5 condensed atoms per element for the 84Sr-87Rb mixture. These quantum gas mixtures constitute an important step towards the production of a quantum gas of polar, open-shell RbSr molecules.

Pasquiou, Benjamin; Tzanova, Slava; Stellmer, Simon; Szczepkowski, Jacek; Parigger, Mark; Grimm, Rudolf; Schreck, Florian

2013-01-01T23:59:59.000Z

46

Magnetohydrodynamic spin waves in degenerate electron-positron-ion plasmas  

SciTech Connect

Low frequency magnetosonic waves are studied in magnetized degenerate electron-positron-ion plasmas with spin effects. Using the fluid equations of magnetoplasma with quantum corrections due to the Bohm potential, temperature degeneracy, and spin magnetization energy, a generalized dispersion relation for oblique magnetosonic waves is derived. Spin effects are incorporated via spin force and macroscopic spin magnetization current. For three different values of angle {theta}, the generalized dispersion relation is reduced to three different relations under the low frequency magnetohydrodynamic assumptions. It is found that the effect of quantum corrections in the presence of positron concentration significantly modifies the dispersive properties of these modes. The importance of the work relevant to compact astrophysical bodies is pointed out.

Mushtaq, A. [TPPD, PINSTECH Nilore, 44000 Islamabad (Pakistan); National Center for Physics, Shahdrah Valley Road, 44000 Islamabad (Pakistan); Maroof, R.; Ahmad, Zulfiaqr [Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan); Qamar, A. [National Center for Physics, Shahdrah Valley Road, 44000 Islamabad (Pakistan); Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan)

2012-05-15T23:59:59.000Z

47

Initial evolution of supports of solutions of quasilinear parabolic equations with degenerate absorption potential  

SciTech Connect

The propagation of supports of solutions of second-order quasilinear parabolic equations is studied; the equations are of the type of nonstationary diffusion, having semilinear absorption with an absorption potential which degenerates on the initial plane. We find sufficient conditions, which are sharp in a certain sense, on the relationship between the boundary regime and the type of degeneration of the potential to ensure the strong localization of solutions. We also establish a weak localization of solutions for an arbitrary potential which degenerates only on the initial plane. Bibliography: 12 titles.

Stepanova, Ekaterina V; Shishkov, Andrey E

2013-03-31T23:59:59.000Z

48

Effect of trapping in a degenerate plasma in the presence of a quantizing magnetic field  

SciTech Connect

Effect of trapping as a microscopic phenomenon in a degenerate plasma is investigated in the presence of a quantizing magnetic field. The plasma comprises degenerate electrons and non-degenerate ions. The presence of the quantizing magnetic field is discussed briefly and the effect of trapping is investigated by using the Fermi-Dirac distribution function. The linear dispersion relation for ion acoustic wave is derived in the presence of the quantizing magnetic field and its influence on the propagation characteristics of the linear ion acoustic wave is discussed. Subsequently, fully nonlinear equations for ion acoustic waves are used to obtain the Sagdeev potential and the investigation of solitary structures. The formation of solitary structures is studied both for fully and partially degenerate plasmas in the presence of a quantizing magnetic field. Both compressive and rarefactive solitons are obtained for different conditions of temperature and magnetic field.

Shah, H. A.; Iqbal, M. J.; Qureshi, M. N. S. [Department of Physics, GC University, Lahore 54000 (Pakistan); Tsintsadze, N. [Department of Physics, GC University, Lahore 54000 (Pakistan); Institute of Physics, Tbilisi 0177 (Georgia); Masood, W. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

2012-09-15T23:59:59.000Z

49

Exponential Mixing of the 3D Stochastic Navier-Stokes Equations Driven by Mildly Degenerate Noises  

SciTech Connect

We prove the strong Feller property and exponential mixing for 3D stochastic Navier-Stokes equation driven by mildly degenerate noises (i.e. all but finitely many Fourier modes being forced) via a Kolmogorov equation approach.

Albeverio, Sergio [Bonn University, Department of Applied Mathematics (Germany); Debussche, Arnaud, E-mail: arnaud.debussche@bretagne.ens-cachan.fr [ENS Cachan Bretagne and IRMAR Campus de Ker Lann (France); Xu Lihu, E-mail: Lihu.Xu@brunel.ac.uk [Brunel University, Mathematics Department (United Kingdom)

2012-10-15T23:59:59.000Z

50

Transverse electric conductivity and dielectric function in quantum non-degenerate collisional plasma by Mermin approach  

E-Print Network (OSTI)

Formulas for transverse conductance in quantum non-degenerate collisional plasma are deduced. The kinetic equation in momentum space in the relaxation approach is used. It is shown, that at $\\hbar\\to 0$ the derived formula transfers to the classical one. It is shown also, that when values of dimensionless wave numbers are small, the conductance formula transfers in the known formula for classical non-degenerate plasmas.

A. V. Latyshev; A. A. Yushkanov

2012-06-18T23:59:59.000Z

51

Universal dynamics of a degenerate unitary Bose gas  

E-Print Network (OSTI)

Understanding the rich behavior that emerges from systems of interacting quantum particles, such as electrons in materials, nucleons in nuclei or neutron stars, the quark-gluon plasma, and superfluid liquid helium, requires investigation of systems that are clean, accessible, and have tunable parameters. Ultracold quantum gases offer tremendous promise for this application largely due to an unprecedented control over interactions. Specifically, $a$, the two-body scattering length that characterizes the interaction strength, can be tuned to any value. This offers prospects for experimental access to regimes where the behavior is not well understood because interactions are strong, atom-atom correlations are important, mean-field theory is inadequate, and equilibrium may not be reached or perhaps does not even exist. Of particular interest is the unitary gas, where $a$ is infinite, and where many aspects of the system are universal in that they depend only on the particle density and quantum statistics. While the unitary Fermi gas has been the subject of intense experimental and theoretical investigation, the degenerate unitary Bose gas has generally been deemed experimentally inaccessible because of three-body loss rates that increase dramatically with increasing $a$. Here, we investigate dynamics of a unitary Bose gas for timescales that are short compared to the loss. We find that the momentum distribution of the unitary Bose gas evolves on timescales fast compared to losses, and that both the timescale for this evolution and the limiting shape of the momentum distribution are consistent with universal scaling with density. This work demonstrates that a unitary Bose gas can be created and probed dynamically, and thus opens the door for further exploration of this novel strongly interacting quantum liquid.

Philip Makotyn; Catherine E. Klauss; David L. Goldberger; Eric. A. Cornell; Deborah S. Jin

2013-08-16T23:59:59.000Z

52

OBSERVATIONAL CONSTRAINTS ON THE DEGENERATE MASS-RADIUS RELATION  

SciTech Connect

The white dwarf mass-radius relationship is fundamental to modern astrophysics. It is central to routine estimation of DA white dwarf masses derived from spectroscopic temperatures and gravities. It is also the basis for observational determinations of the white dwarf initial-final-mass relation. Nevertheless, definitive and detailed observational confirmations of the mass-radius relation (MRR) remain elusive owing to a lack of sufficiently accurate white dwarf masses and radii. Current best estimates of masses and radii allow only broad conclusions about the expected inverse relation between masses and radii in degenerate stars. In this paper, we examine a restricted set of 12 DA white dwarf binary systems for which accurate (1) trigonometric parallaxes, (2) spectroscopic effective temperatures and gravities, and (3) gravitational redshifts are available. We consider these three independent constraints on mass and radius in comparison with an appropriate evolved MRR for each star. For the best-determined systems it is found that the DA white dwarfs conform to evolve theoretical MRRs at the 1{sigma} to 2{sigma} level. For the white dwarf 40 Eri B (WD 0413-077) we find strong evidence for the existence of a 'thin' hydrogen envelope. For other stars improved parallaxes will be necessary before meaningful comparisons are possible. For several systems current parallaxes approach the precision required for the state-of-the-art mass and radius determinations that will be obtained routinely from the Gaia mission. It is demonstrated here how these anticipated results can be used to firmly constrain details of theoretical mass-radius determinations.

Holberg, J. B. [Lunar and Planetary Laboratory, 1541 East University Boulevard, Sonett Space Sciences Building, University of Arizona, Tucson, AZ 85721 (United States); Oswalt, T. D. [Florida Institute of Technology, Melbourne, FL 32901 (United States); Barstow, M. A., E-mail: holberg@argus.lpl.arizona.edu, E-mail: toswalt@fit.edu, E-mail: mab@le.ac.uk [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

2012-03-15T23:59:59.000Z

53

Longitudinal permeability of collisional plasmas under arbitrary degree of degeneration of electron gas  

E-Print Network (OSTI)

Electric conductivity and dielectric permeability of the non-degenerate electronic gas for the collisional plasmas under arbitrary degree of degeneration of electron gas is found. The kinetic equation of Wigner - Vlasov - Boltzmann with collision integral in relaxation form BGK (Bhatnagar, Gross and Krook) in coordinate space is used. Dielectric permeability with using of the relaxation equation in the momentum space has been received by Mermin. Comparison with Mermin's formula has been realized. It is shown, that in the limit when Planck's constant tends to zero expression for dielectric permeability passes in the classical.

A. V. Latyshev; A. A. Yushkanov

2010-03-04T23:59:59.000Z

54

Numerical identification of parameters for a strongly degenerate convection--diffusion problem modelling centrifugation of flocculated suspensions  

Science Conference Proceedings (OSTI)

This paper presents the identification of parameters in the flux and diffusion functions for a quasilinear strongly degenerate parabolic equation which models the centrifugation of flocculated suspensions. We consider both a rotating tube and a basket ... Keywords: Degenerate parabolic differential equation, Inverse problem, Numerical methods

S. Berres; R. Brger; A. Coronel; M. Seplveda

2005-03-01T23:59:59.000Z

55

Progress in Retinal and Eye Research 22 (2003) 607655 Neural remodeling in retinal degeneration  

E-Print Network (OSTI)

, Department of Ophthalmology, University of Utah School of Medicine, 50 N Medical Center, Salt Lake City, UT Accepted 31 March 2003 Abstract Mammalian retinal degenerations initiated by gene defects in rods, cones in the mammalian retina generally progress through three phases. Phase 1 initiates with expression of a primary

Marc, Robert E.

56

Measurement of the elements of. chi. sup (3) for degenerate four-wave mixing in OH  

DOE Green Energy (OSTI)

Measurements of the polarization characteristics of degenerate four-wave mixing transitions in the A{sup 2}{sigma}{sup +} {yields} X{sup 2}{Pi}(0,0) band of OH are found to disagree with theory and are attributed to population gratings from open-system effects.

Rahn, L.A. (Sandia National Labs., Livermore, CA (United States)); Brown, M.S. (SRI International, Menlo Park, CA (United States))

1992-01-01T23:59:59.000Z

57

Homogenization of a degenerate parabolic problem in a highly heterogeneous medium with highly anisotropic fibers  

Science Conference Proceedings (OSTI)

We consider the homogenization of a heat transfer problem in a periodic medium, consisting of a set of highly anisotropic fibers surrounded by insulating layers, the whole being embedded in a third material having a conductivity of order 1. The conductivity ... Keywords: Degenerate parabolic problem, Highly anisotropic fibers, Highly heterogeneous medium, Homogenization

Ahmed Boughammoura

2009-01-01T23:59:59.000Z

58

Harnack Inequalities for NonNegative Solutions to Degenerate and Singular Parabolic Partial  

E-Print Network (OSTI)

Harnack Inequalities for Non­Negative Solutions to Degenerate and Singular Parabolic Partial, Local Behaviour of Solutions of Quasi­linear Parabolic Equations, Arch. Rat. Mech. Anal 25, (1967), 81 Parabolic Equations with Measurable Coefficients, Arch. Rational. Mech. Anal. 118, (1992), 257­271. [4] E

Gianazza, Ugo

59

Direct Observation of Sub-Poissonian Number Statistics in a Degenerate Bose Gas  

E-Print Network (OSTI)

We report the direct observation of sub-Poissonian number fluctuation for a degenerate Bose gas confined in an optical trap. Reduction of number fluctuations below the Poissonian limit is observed for average numbers that range from 300 to 60 atoms.

C. -S. Chuu; F. Schreck; T. P. Meyrath; J. L. Hanssen; G. N. Price; M. G. Raizen

2005-08-18T23:59:59.000Z

60

Optical imaging through turbid media with a degenerate four-wave mixing correlation time gate  

DOE Patents (OSTI)

Optical imaging through turbid media is demonstrated using a degenerate four-wave mixing correlation time gate. An apparatus and method for detecting ballistic and/or snake light while rejecting unwanted diffusive light for imaging structures within highly scattering media are described. Degenerate four-wave mixing (DFWM) of a doubled YAG laser in rhodamine 590 is used to provide an ultrafast correlation time gate to discriminate against light that has undergone multiple scattering and therefore has lost memory of the structures within the scattering medium. Images have been obtained of a test cross-hair pattern through highly turbid suspensions of whole milk in water that are opaque to the naked eye, which demonstrates the utility of DFWM for imaging through turbid media. Use of DFWM as an ultrafast time gate for the detection of ballistic and/or snake light in optical mammography is discussed.

Sappey, Andrew D. (Golden, CO)

1998-04-14T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Planar and nonplanar ion acoustic shock waves in relativistic degenerate astrophysical electron-positron-ion plasmas  

SciTech Connect

We have studied the propagation of ion acoustic shock waves involving planar and non-planar geometries in an unmagnetized plasma, whose constituents are non-degenerate ultra-cold ions, relativistically degenerate electrons, and positrons. By using the reductive perturbation technique, Korteweg-deVries Burger and modified Korteweg-deVries Burger equations are derived. It is shown that only compressive shock waves can propagate in such a plasma system. The effects of geometry, the ion kinematic viscosity, and the positron concentration are examined on the ion acoustic shock potential and electric field profiles. It is found that the properties of ion acoustic shock waves in a non-planar geometry significantly differ from those in planar geometry. The present study has relevance to the dense plasmas, produced in laboratory (e.g., super-intense laser-dense matter experiments) and in dense astrophysical objects.

Ata-ur-Rahman,; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2013-04-15T23:59:59.000Z

62

Theory of degenerate three-wave mixing using circuit QED in solid-state circuits  

Science Conference Proceedings (OSTI)

We study the theory of degenerate three-wave mixing and the generation of squeezed microwaves using circuit quantum electrodynamics in solid state circuits. The Hamiltonian for degenerate three-wave mixing, which seemed to be given phenomenologically in quantum optics, is derived by quantum mechanical calculations. The nonlinear medium needed in three-wave mixing is composed of a series of superconducting charge qubits which are located inside two superconducting transmission-line resonators. Here, the multiqubit ensemble is present to enhance the effective coupling constant between the two modes in the transmission-line resonators. In the squeezing process, the qubits are kept in their ground states so that their decoherence does not corrupt the squeezing. The main obstacle preventing a large squeezing efficiency is the decay rate of the transmission-line resonator.

Cao, Ye [Key Laboratory of Atomic and Molecular Nanosciences and Department of Physics, Tsinghua University, Beijing 100084 (China); Huo, Wen Yi [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Ai, Qing [Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Long, Gui Lu [Key Laboratory of Atomic and Molecular Nanosciences and Department of Physics, Tsinghua University, Beijing 100084 (China); Tsinghua National Laboratory For Information Science and Technology, Beijing 100084 (China)

2011-11-15T23:59:59.000Z

63

Effects of trapping and finite temperature in a relativistic degenerate plasma  

SciTech Connect

In the present work, we have undertaken, for the first time, investigation on the effect of trapping on the formation of solitary structures in relativistic degenerate plasmas. Such plasmas have been observed in dense astrophysical objects, and in laboratory these may result due to the interaction of intense lasers with matter. We have used the relativistic Fermi-Dirac distribution to describe the dynamics of the degenerate trapped electrons by solving the kinetic equation. The Sagdeev potential approach has been employed to obtain the arbitrary amplitude solitary structures both when the plasma has been considered cold and when small temperature effects have been taken into account. The theoretical results obtained have been analyzed numerically for different parameter values, and the results have been presented graphically.

Shah, H. A.; Qureshi, M. N. S. [Physics Department, GC University, Lahore 54000 (Pakistan); Masood, W. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); Tsintsadze, N. L. [Physics Department, GC University, Lahore 54000 (Pakistan); Institute of Physics, Georgian Academy of Sciences, Tblisi 380077 (Georgia)

2011-10-15T23:59:59.000Z

64

Analysis of the RPE sheet in the rd10 retinal degeneration model  

SciTech Connect

The normal RPE sheet in the C57Bl/6J mouse is subclassified into two major tiling patterns: A regular generally hexagonal array covering most of the surface and a 'soft network' near the ciliary body made of irregularly shaped cells. Physics models predict these two patterns based on contractility and elasticity of the RPE cell, and strength of cellular adhesion between cells. We hypothesized and identified major changes in RPE regular hexagonal tiling pattern in rdl0 compared to C57BL/6J mice. RPE sheet damage was extensive but occurred in rd10 later than expected, after most retinal degeneration. RPE sheet changes occur in zones with a bullseye pattern. In the posterior zone around the optic nerve RPE cells take on larger irregular and varied shapes to form an intact monolayer. In mid periphery, there is a higher than normal density of cells that progress into involuted layers of RPE under the retina. The periphery remains mostly normal until late stages of degeneration. The number of neighboring cells varies widely depending on zone and progression. RPE morphology continues to deteriorate long after the photoreceptors have degenerated. The RPE cells are bystanders to the rd10 degeneration within photo receptors, and the collateral damage to the RPE sheet resembles stimulation of migration or chemotaxis. Quantitative measures of the tiling patterns and histopathology detected here, scripted in a pipeline written in Perl and Cell Profiler (an open source Matlab plugin), are directly applicable to RPE sheet images from noninvasive fundus autofluorescence (FAF), adaptive optics confocal scanning laser ophthalmoscope (AO-cSLO), and spectral domain optical coherence tomography (SD-OCT) of patients with early stage AMD or RP.

Jiang, Yi [Los Alamos National Laboratory

2011-01-04T23:59:59.000Z

65

Degenerate mixing of plasma waves on cold, magnetized single-species plasmas  

SciTech Connect

In the cold-fluid dispersion relation {omega}={omega}{sub p}/[1+(k{sub perpendicular}/k{sub z}){sup 2}]{sup 1/2} for Trivelpiece-Gould waves on an infinitely long magnetized plasma cylinder, the transverse and axial wavenumbers appear only in the combination k{sub perpendicular}/k{sub z}. As a result, for any frequency {omega}<{omega}{sub p}, there are infinitely many degenerate waves, all having the same value of k{sub perpendicular}/k{sub z}. On a cold finite-length plasma column, these degenerate waves reflect into one another at the ends; thus, each standing-wave normal mode of the bounded plasma is a mixture of many degenerate waves, not a single standing wave as is often assumed. A striking feature of the many-wave modes is that the short-wavelength waves often add constructively along resonance cones given by dz/dr={+-}({omega}{sub p}{sup 2}/{omega}{sup 2}-1){sup 1/2}. Also, the presence of short wavelengths in the admixture for a predominantly long-wavelength mode enhances the viscous damping beyond what the single-wave approximation would predict. Here, numerical solutions are obtained for modes of a cylindrical plasma column with rounded ends. Exploiting the fact that the modes of a spheroidal plasma are known analytically (the Dubin modes), a perturbation analysis is used to investigate the mixing of low-order, nearly degenerate Dubin modes caused by small deformations of a plasma spheroid.

Anderson, M. W.; O'Neil, T. M.; Dubin, D. H. E.; Gould, R. W. [Physics Department, University of California at San Diego, La Jolla, California 92093 (United States)

2011-10-15T23:59:59.000Z

66

Homogenization of a singularly perturbed degenerated parabolic equation and application to seabed dune and megaripple morphodynamics in tided environment  

E-Print Network (OSTI)

In this paper we build models for short-term, mean-term and long-term dynamics of dune and megariple morphodynamics. They are models that are degenerated parabolic equations which are, moreover, singularly perturbed. We, then give an existence and uniqueness result for the short-term and mean-term models. This result is based on a time-space periodic solution existence result for degenerated parabolic equation that we set out. Finally the short-term model is homogenized.

Faye, Ibrahima; Seck, Diaraf

2009-01-01T23:59:59.000Z

67

POST-TRAUMATIC DEGENERATION AND REGENERATION OF SYNAPSES IN THE ACTION OF IONIZING RADIATION  

SciTech Connect

A study was made of degeneration and regeneration of synapses in the upper cervical ganglion and section of the sympathetic trunk on the neck of cats after total single x ray irradiation in a dose of 30, 100, or 500 r. There was an acceleration of these processes after the action of low doses, and delay after the action of high doses. The synapses first restored undergo considerable structural changes with the lapse of time and become small and delicate. The scar at the site of nerve section considerably diminishes in size after the high doses of x-ray irradiation. (auth)

Babmindra, V.P.

1962-01-01T23:59:59.000Z

68

Magnetism of a relativistic degenerate electron gas in a strong magnetic field  

SciTech Connect

The magnetization and magnetic susceptibility of a degenerate electron gas in a strong magnetic field in which electrons are located on the ground Landau level and the electron gas has the properties of a nonlinear paramagnet have been calculated. The paradoxical properties of the electron gas under these conditions-a decrease in the magnetization with the field and an increase in the magnetization with the temperature-have been revealed. It has been shown that matter under the corresponding conditions of neutron stars is a paramagnet with a magnetic susceptibility of {chi} {approx} 0.001.

Skobelev, V. V., E-mail: v.skobelev@inbox.ru [Moscow State Industrial University (Russian Federation)

2012-09-15T23:59:59.000Z

69

Born-Oppenheimer-type Approximations for Degenerate Potentials: Recent Results and a Survey on the area  

E-Print Network (OSTI)

This paper is devoted to the asymptotics of eigenvalues for a Schr\\"o-dinger operator in the case when the potential V does not tend to infinity at infinity. Such a potential is called degenerate. The point is that the set in the phase space where the associated hamiltonian is smaller than a fixed energy E may have an infinite volume, so that the Weyl formula which gives the behaviour of the counting function has to be revisited. We recall various results in this area, in the classical context as well as in the semi-classical one and comment the different methods. In sections 3, 4 we present our joint works with A Morame, (Universit\\'e de Nantes),concerning a degenerate potential V(x) =f(y) g(z), where g is assumed to be a homogeneous positive function of m variables, and f is a smooth and strictly positive function of n variables, with a minimum in 0. In the case where f tends to infinity at infinity, we give the semi-classical asymptotic behaviour of the number of eigenvalues less than a fixed energy . Then we give a sharp estimate of the low eigenvalues, using a Born Oppenheimer approximation. With a refined approach we localize also higher energies . Finally we apply the previous methods to a class of potentials which vanish on a regular hypersurface.

Francoise Truc

2009-01-05T23:59:59.000Z

70

MSC response to pH levels found in degenerating intervertebral discs  

Science Conference Proceedings (OSTI)

Painful degenerative disc disease is a major health problem and for successful tissue regeneration, MSCs must endure and thrive in a harsh disc microenvironment that includes matrix acidity as a critical factor. MSCs were isolated from bone marrow of Sprague-Dawley rats from two different age groups (<1 month, n = 6 and 4-5 months, n = 6) and cultured under four different pH conditions representative of the healthy, mildly or severely degenerated intervertebral disc (pH 7.4, 7.1, 6.8, and 6.5) for 5 days. Acidity caused an inhibition of aggrecan, collagen-1, and TIMP-3 expression, as well as a decrease in proliferation and viability and was associated with a change in cell morphology. Ageing had generally minor effects but young MSCs maintained greater mRNA expression levels. As acidic pH levels are typical of increasingly degenerated discs, our findings demonstrate the importance of early interventions and predifferentiation when planning to use MSCs for reparative treatments.

Wuertz, Karin [School of Engineering, University of Vermont, Burlington, Vermont (United States); Spine Research Group, Competence Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich (Switzerland)], E-mail: wuertz@cabmm.uzh.ch; Godburn, Karolyn; Iatridis, James C. [School of Engineering, University of Vermont, Burlington, Vermont (United States)

2009-02-20T23:59:59.000Z

71

Transverse electric conductivity and dielectric permeability in quantum degenerate collisional plasma with variable collision frequency in Mermin's approach  

E-Print Network (OSTI)

Formulas for transverse conductance and dielectric permeability in quantum degenerate collisional plasma with arbitrary variable collision frequency in Mermin's approach are deduced. Frequency of collisions of particles depends arbitrarily on a wave vector. For this purpose the kinetic Shr\\"{o}dinger - Boltzmann equation with collision integral of relaxation type in momentum space is applied. The case of degenerate Fermi plasma is allocated and investigated. The special case of frequency of collisions proportional to the module of a wave vector is considered. The graphic analysis of the real and imaginary parts of dielectric function is made.

Latyshev, A V

2013-01-01T23:59:59.000Z

72

Estimates in Generalized Morrey Spaces for Weak Solutions to Divergence Degenerate Parabolic Systems  

E-Print Network (OSTI)

Let $\\mathrm{X}=(X_{1},...,X_{q})$ be a family of real smooth vector fields satisfying H\\"{o}mander's condition. The purpose of this paper is to establish gradient estimates in generalized Morrey spaces for weak solutions of the divergence degenerate parabolic system related to $X$ :%\\[u_{t}^{i}+X_{\\alpha}^{\\ast}(a_{ij}^{\\alpha\\beta}(z)X_{\\beta}u^{j}%)=g_{i}+X_{\\alpha}^{\\ast}f_{i}^{\\alpha}(z), \\] where $\\alpha,\\beta=1,2,...,q,$ $i,j=1,2,...,N$, $X_{\\alpha}^{\\ast}$ is the transposed vector field of $X_{\\alpha}$, $z=(t,x)\\in{\\mathbb{R}}^{n+1}$, and coefficients $a_{ij}^{\\alpha\\beta}(z)$ belong to the space $VMO$ induced by the vector fields $X_{1}, ...,X_{q}$.

Dong, Yan; Niu, Pengcheng

2011-01-01T23:59:59.000Z

73

Nonlinear screening effect in an ultrarelativistic degenerate electron-positron gas  

SciTech Connect

Nonlinear screening process in an ultrarelativistic degenerate electron-positron gas has been investigated by deriving a generalized nonlinear Poisson equation for the electrostatic potential. In the simple one-dimensional case, the nonlinear Poisson equation leads to Debye-like (Coulomb-like) solutions at distances larger (less) than the characteristic length. When the electrostatic energy is larger than the thermal energy, this nonlinear Poisson equation converts into the relativistic Thomas-Fermi equation whose asymptotic solution in three dimensions shows that the potential field goes to zero at infinity much more slowly than the Debye potential. The possibility of the formation of a bound state in electron-positron plasma is also indicated. Further, it is investigated that the strong spatial fluctuations of the potential field may reduce the screening length and that the root mean square of this spatial fluctuating potential goes to zero for large r rather slowly as compared to the case of the Debye potential.

Tsintsadze, N. L. [Salam Chair in Physics, Government College University, Lahore 54000 (Pakistan); Department of Physics, Government College University, Lahore 54000 (Pakistan); Rasheed, A.; Shah, H. A. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, Government College University, Lahore 54000 (Pakistan)

2009-11-15T23:59:59.000Z

74

Low frequency electromagnetic oscillations in dense degenerate electron-positron pair plasma, with and without ions  

SciTech Connect

Quantum plasma oscillations are studied in a strongly magnetized, ultra-dense plasma with degenerate electrons and positrons. The dispersive role of electron and positron quantum effects on low frequency (in comparison to electron cyclotron frequency) shear electromagnetic wave is investigated by employing hydrodynamic formulation. In the presence of ions, the density balance changes, and the electromagnetic wave (with frequency lower than the ion cyclotron frequency) is shown to couple with electrostatic ion mode under certain conditions. For such low frequency waves, it is also seen that the contribution of electron and positron degeneracy pressure is dominant as compared to their diffraction effects. The results are analyzed numerically for illustrative purpose pointing out their relevance to the dense laboratory (e.g., super-intense laser-dense matter interactions) and astrophysical plasmas.

Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Ayub, M. K. [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Pohang University of Science and Technology (POSTECH), Pohang, Gyunbuk 790-784 (Korea, Republic of); Ahmad, Ali [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad (Pakistan); Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

2012-10-15T23:59:59.000Z

75

Ion-acoustic solitary waves in ultra-relativistic degenerate pair-ion plasmas  

SciTech Connect

The arbitrary and the small amplitude ion-acoustic solitary waves (IASWs) have been studied. The former is studied by using the Sagdeev pseudo-potential approach in a plasma consisting of the degenerate ultrarelativistic electrons, positrons, and the non-relativistic classical ions. It is seen that only compressive solitary waves can propagate through such plasmas. The numerical calculations show that the region of existence of the ion-acoustic solitary waves depends upon the positron (ion) number density and the plasma thermal temperature. This study is appropriate for applications in inertial confinement fusion laboratory research as well as the study of astrophysical dense objects such as white dwarf and dense neutron stars.

Rasheed, A.; Tsintsadze, N. L. [Department of Physics, G.C. University, Lahore 54000 (Pakistan); Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, G.C. University, Lahore 54000 (Pakistan)

2011-11-15T23:59:59.000Z

76

WHITE DWARF/M DWARF BINARIES AS SINGLE DEGENERATE PROGENITORS OF TYPE Ia SUPERNOVAE  

SciTech Connect

Limits on the companions of white dwarfs in the single-degenerate scenario for the origin of Type Ia supernovae (SNe Ia) have gotten increasingly tight, yet igniting a nearly Chandrasekhar mass C/O white dwarf from a condition of near hydrostatic equilibrium provides compelling agreement with observed spectral evolution. The only type of non-degenerate stars that survive the tight limits, M{sub V} {approx}> 8.4 on the SN Ia in SNR 0509-67.5 and M{sub V} {approx}> 9.5 in the remnant of SN 1572, are M dwarfs. While M dwarfs are observed in cataclysmic variables, they have special properties that have not been considered in most work on the progenitors of SNe Ia: they have small but finite magnetic fields and they flare frequently. These properties are explored in the context of SN Ia progenitors. White dwarf/M dwarf pairs may be sufficiently plentiful to provide, in principle, an adequate rate of explosions even with slow orbital evolution due to magnetic braking or gravitational radiation. Even modest magnetic fields on the white dwarf and M dwarf will yield adequate torques to lock the two stars together, resulting in a slowly rotating white dwarf, with the magnetic poles pointing at one another in the orbital plane. The mass loss will be channeled by a 'magnetic bottle' connecting the two stars, landing on a concentrated polar area on the white dwarf. This enhances the effective rate of accretion compared to spherical accretion. Luminosity from accretion and hydrogen burning on the surface of the white dwarf may induce self-excited mass transfer. The combined effects of self-excited mass loss, polar accretion, and magnetic inhibition of mixing of accretion layers give possible means to beat the 'nova limit' and grow the white dwarf to the Chandrasekhar mass even at rather moderate mass accretion rates.

Wheeler, J. Craig, E-mail: wheel@astro.as.utexas.edu [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

2012-10-20T23:59:59.000Z

77

A co-rotational 8-node degenerated thin-walled element with assumed natural strain and enhanced assumed strain  

Science Conference Proceedings (OSTI)

In recent years, solid-shell elements with the absence of the rotational degrees of freedom have considerable attentions in analyzing thin structures. In this paper, the non-linear formulation of a co-rotational 8-node degenerated thin-walled element ... Keywords: 8-Node solid element, Assumed natural strains, Co-rotational method, Enhanced assumed strains, Geometrical nonlinearity

Pramin Norachan; Songsak Suthasupradit; Ki-Du Kim

2012-03-01T23:59:59.000Z

78

Measurement of the elements of {chi}{sup (3)} for degenerate four-wave mixing in OH  

DOE Green Energy (OSTI)

Measurements of the polarization characteristics of degenerate four-wave mixing transitions in the A{sup 2}{sigma}{sup +} {yields} X{sup 2}{Pi}(0,0) band of OH are found to disagree with theory and are attributed to population gratings from open-system effects.

Rahn, L.A. [Sandia National Labs., Livermore, CA (United States); Brown, M.S. [SRI International, Menlo Park, CA (United States)

1992-02-01T23:59:59.000Z

79

Reproducing neutrino effects on the matter power spectrum through a degenerate Fermi gas approach  

E-Print Network (OSTI)

Modifications on the predictions about the matter power spectrum based on the hypothesis of a tiny contribution from a degenerate Fermi gas (DFG) test-fluid to some dominant cosmological scenario are investigated. Reporting about the systematic way of accounting for all the cosmological perturbations, through the Boltzmann equation we obtain the analytical results for density fluctuation, $\\delta$, and fluid velocity divergence, $\\theta$, of the DFG. Small contributions to the matter power spectrum are analytically obtained for the radiation-dominated background, through an ultra-relativistic approximation, and for the matter-dominated and $\\Lambda$-dominated eras, through a non-relativistic approximation. The results can be numerically reproduced and compared with those of considering non-relativistic and ultra-relativistic neutrinos into the computation of the matter power spectrum. Lessons concerning the formation of large scale structures of a DFG are depicted, and consequent deviations from standard $\\Lambda$CDM predictions for the matter power spectrum (with and without neutrinos) are quantified.

E. L. D. Perico; Alex E. Bernardini

2011-02-19T23:59:59.000Z

80

Acceleration and dynamics of an electron in the degenerate and magnetized plasma elliptical waveguide  

SciTech Connect

The dynamics and energy gain of an electron in the field of a transverse magnetic wave propagating inside an elliptical degenerate plasma waveguide is analytically investigated by finding the field components of the TM{sub mr} mode in this waveguide. Besides, by solving the relativistic momentum and energy equations the deflection angle and the acceleration gradient of the electron in the waveguide are obtained. Furthermore, the field components of the hybrid mode and the transferred power in the presence of the magnetic field in this waveguide are found. Also by applying the boundary conditions at the plasma-conductor interface, we calculate the dispersion relation. It is shown that the cutoff frequency of this mode is dependent on the plasma density but independent of the magnetic field. Then, a single-electron model for numerical calculations of the electron deflection angle and acceleration gradient inside the magnetized plasma-filled elliptical waveguide is generally presented to be used as a cascading process for the acceleration purposes.

Abdoli-Arani, A.; Jazi, B. [Department of Photonics, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Shokri, B. [Physics Department and Laser-Plasma Research Institute, G. C. Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

2013-02-15T23:59:59.000Z

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81

Electrostatic soliton and double layer structures in unmagnetized degenerate pair plasmas  

SciTech Connect

The acoustic solitons and double layers are studied in unmagnetized quantum electron-positron plasmas in the presence of stationary ions. The quantum hydrodynamic model is employed and reductive perturbation method is used to derive the Korteweg-de Vries (KdV) and extended KdV equations for solitons and double layers, respectively. It is found that in the linear limit both slow acoustic and fast Langmuir waves can propagate in such type of quantum plasmas like in classical pair-ion or pair plasmas. The amplitude and width of the electrostatic solitons are found to be decreasing with the increase in concentration of positrons (or decrease in the concentration of ions) in degenerate electron-positron-ion plasmas. It is found that only rarefactive double layer can exist in such plasmas which depend on various parameters. The dependence of double layer structure on ion concentration and quantum diffraction effects of electrons and positrons are also discussed. The results are also elaborated graphically by considering dense plasma parameters in the outer layers of astrophysical objects such as white dwarfs and neutron stars.

Mahmood, S. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); National Centre for Physics, Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Department of Physics and Applied Mathematics (DPAM), PIEAS, P.O. Nilore, Islamabad 44000 (Pakistan); Khan, S. A. [National Centre for Physics, Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Department of Physics, COMSATS Institute of Information Technology (CIIT), Islamabad 44000 (Pakistan); Ur-Rehman, H. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); Department of Physics and Applied Mathematics (DPAM), PIEAS, P.O. Nilore, Islamabad 44000 (Pakistan)

2010-11-15T23:59:59.000Z

82

THE SHOENBERG EFFECT IN A RELATIVISTIC DEGENERATE ELECTRON GAS AND OBSERVATIONAL EVIDENCE IN MAGNETARS  

SciTech Connect

The electron gas inside a neutron star is highly degenerate and relativistic. Due to electron-electron magnetic interactions, the differential susceptibility can equal or exceed one, which causes the magnetic system of the neutron star to become metastable or unstable. The Fermi liquid of nucleons under the crust can be in a metastable state, while the crust is unstable to the formation of layers of alternating magnetization. The change of the magnetic stress acting on adjacent domains can result in a series of shifts or fractures in the crust. The release of magnetic free energy and elastic energy in the crust can cause the bursts observed in magnetars. Simultaneously, a series of shifts or fractures in the deep crust that is close to the Fermi liquid of nucleons can trigger a phase transition of the Fermi liquid of nucleons from a metastable state to a stable state. The magnetic free energy released in the Fermi liquid of nucleons corresponds to the giant flares observed in some magnetars.

Wang Zhaojun; Lue Guoliang; Zhu Chunhua; Huo Wensheng, E-mail: xjdxwzj@sohu.com, E-mail: guolianglv@gmail.com [School of Physical Science and Technology, Xinjiang University, Urumqi 830046 (China)

2013-08-20T23:59:59.000Z

83

THE CORE COMPOSITION OF A WHITE DWARF IN A CLOSE DOUBLE-DEGENERATE SYSTEM  

Science Conference Proceedings (OSTI)

We report the identification of the double-degenerate system NLTT 16249 that comprises a normal, hydrogen-rich (DA) white dwarf and a peculiar, carbon-polluted white dwarf (DQ) showing photospheric traces of nitrogen. We disentangled the observed spectra and constrained the properties of both stellar components. In the evolutionary scenario commonly applied to the sequence of DQ white dwarfs, both carbon and nitrogen would be dredged up from the core. The C/N abundance ratio ( Almost-Equal-To 50) in the atmosphere of this unique DQ white dwarf suggests the presence of unprocessed material ({sup 14}N) in the core or in the envelope. Helium burning in the DQ progenitor may have terminated early on the red giant branch after a mass-ejection event leaving unprocessed material in the core, although current mass estimates do not favor the presence of a low-mass helium core. Alternatively, some nitrogen in the envelope may have survived an abridged helium-core burning phase prior to climbing the asymptotic giant branch. Based on available data, we estimate a relatively short orbital period (P {approx}< 13 hr) and ongoing spectroscopic observations will help determine precise orbital parameters.

Vennes, S.; Kawka, A. [Kitt Peak National Observatory, National Optical Astronomy Observatory (United States)

2012-01-20T23:59:59.000Z

84

Non-local correlation and quantum discord in two atoms in the non-degenerate model  

SciTech Connect

By using geometric quantum discord (GQD) and measurement-induced nonlocality (MIN), quantum correlation is investigated for two atoms in the non-degenerate two-photon Tavis-Cummings model. It is shown that there is no asymptotic decay for MIN while asymptotic decay exists for GQD. Quantum correlations can be strengthened by introducing the dipole-dipole interaction. The evolvement period of quantum correlation gets shorter with the increase in the dipole-dipole parameter. It is found that there exists not only quantum nonlocality without entanglement but also quantum nonlocality without quantum discord. Also, the MIN and GQD are raised rather than entanglement, and also with weak initial entanglement, there are MIN and entanglement in a interval of death quantum discord. - Highlights: Black-Right-Pointing-Pointer Geometric quantum discord (GQD) and measurement induced nonlocality (MIN) are used to investigate the correlations of two two-level atoms. Black-Right-Pointing-Pointer There is no asymptotic decay for MIN while asymptotic decay exists for GQD. Black-Right-Pointing-Pointer Quantum correlations can be strengthened by introducing the dipole-dipole interaction. Black-Right-Pointing-Pointer There exists not only quantum nonlocality without entanglement but also without discord. Black-Right-Pointing-Pointer Weak initial entanglement leads to MIN and entanglement in intervals of death discord.

Mohamed, A.-B.A., E-mail: Abdelbastm@yahoo.com

2012-12-15T23:59:59.000Z

85

Small Heat Shock Protein aA-Crystallin Prevents Photoreceptor Degeneration in Experimental  

E-Print Network (OSTI)

The small heat shock protein, aA-crystallin null (aA2/2) mice are known to be more prone to retinal degeneration than the wild type mice in Experimental Autoimmune Uveoretinitis (EAU). In this report we demonstrate that intravenous administration of aA preserves retinal architecture and prevents photoreceptor damage in EAU. Interestingly, only aA and not aB-crystallin (aB), a closely related small heat shock protein works, pointing to molecular specificity in the observed retinal protection. The possible involvement of aA in retinal protection through immune modulation is corroborated by adaptive transfer experiments, (employing aA2/2 and wild type mice with EAU as donors and Rag22/2 as the recipient mice), which indicate that aA protects against the autoimmune challenge by modulating the systemic B and T cell immunity. We show that aA administration causes marked reduction in Th1 cytokines (TNF-a, IL-12 and IFN-c), both in the retina and in the spleen; notably, IL-17 was only reduced in the retina suggesting local intervention. Importantly, expression of Toll-like receptors and their associated adaptors is also inhibited suggesting that aA protection, against photoreceptor

Autoimmune Uveitis; Narsing A. Rao; Sindhu Saraswathy; Geeta Pararajasegaram; Suraj P. Bhat

2012-01-01T23:59:59.000Z

86

Common Variants at 9p21 and 8q22 Are Associated with Increased Susceptibility to Optic Nerve Degeneration in Glaucoma  

E-Print Network (OSTI)

Optic nerve degeneration caused by glaucoma is a leading cause of blindness worldwide. Patients affected by the normal-pressure form of glaucoma are more likely to harbor risk alleles for glaucoma-related optic nerve ...

Ernst, Jason M.

87

Statistical Characterization and Segmentation of Drusen in Fundus Images  

SciTech Connect

Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

Santos-Villalobos, Hector J [ORNL; Karnowski, Thomas Paul [ORNL; Aykac, Deniz [ORNL; Giancardo, Luca [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Nichols, Trent L [ORNL; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

88

Comment on the article 'Solitary waves and double layers in an ultra-relativistic degenerate dusty electron-positron-ion plasma'[Phys. Plasmas 19, 033705 (2012)  

SciTech Connect

More recently, Roy et al.[Phys. Plasmas 19, 033705 (2012)] have investigated the occurrence of nonlinear solitary and double-layers in an ultrarelativistic dusty electron-positron-ion degenerate plasma using a Sagdeev potential method. They have considered a full parametric examination on Mach-number criteria for existence of such nonlinear excitations using the specific degeneracy limits of Chandrasekhar equation of state (EoS) for Fermi-Dirac plasmas. In this comment, we point-out a misleading extension of polytropic EoS to study the Fermi-Dirac relativistically degenerate plasmas.

Akbari-Moghanjoughi, M. [Department of Physics, Faculty of Sciences, Azarbaijan University of Tarbiat Moallem, 51745-406 Tabriz (Iran, Islamic Republic of)

2012-06-15T23:59:59.000Z

89

EVOLUTION OF POST-IMPACT COMPANION STARS IN SN Ia REMNANTS WITHIN THE SINGLE-DEGENERATE SCENARIO  

Science Conference Proceedings (OSTI)

The nature of the progenitor systems of Type Ia supernovae is still uncertain. One way to distinguish between the single-degenerate scenario and double-degenerate scenario is to search for the post-impact remnant star. To examine the characteristics of the post-impact remnant star, we have carried out three-dimensional hydrodynamic simulations of supernova impacts on main-sequence-like stars. We explore the evolution of the post-impact remnants using the stellar evolution code MESA. We find that the luminosity and radius of the remnant star dramatically increase just after the impact. After the explosion, post-impact companions continue to expand on a progenitor-dependent timescale of {approx}10{sup 2.5}-10{sup 3} years before contracting. It is found that the time evolution of the remnant star is dependent not only on the amount of energy absorbed but also on the depth of the energy deposition. We examine the viability of the candidate star Tycho G as the possible remnant companion in Tycho's supernova by comparing it to the evolved post-impact remnant stars in our simulations. The closest model in our simulations has a similar effective temperature, but the luminosity and radius are twice as large. By examining the angular momentum distribution in our simulations, we find that the surface rotational speed could drop to {approx}10 km s{sup -1} if the specific angular momentum is conserved during the post-impact evolution, implying that Tycho G cannot be completely ruled out because of its low surface rotation speed.

Pan, Kuo-Chuan; Ricker, Paul M. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Taam, Ronald E., E-mail: kpan2@illinois.edu, E-mail: pmricker@illinois.edu, E-mail: taam@northwestern.edu [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

2012-11-20T23:59:59.000Z

90

Biocompatibility of an implantable ophthalmic drug delivery device  

E-Print Network (OSTI)

Diseases of the posterior eye present clinicians with a treatment challenge mainly due to the region's inaccessible location. Several drugs, including those available for the treatment of exudative age-related macular ...

Cohen, Sarah J. (Sarah Jennifer)

2007-01-01T23:59:59.000Z

91

Monte Carlo Study of Strongly-Interacting Degenerate Fermions: a Model for Voltage-Biased Bilayer Graphene  

E-Print Network (OSTI)

We formulate a model of N_f=4 flavors of relativistic fermion in 2+1d in the presence of a chemical potential mu coupled to two flavor doublets with opposite sign, akin to isopsin chemical potential in QCD. This is argued to be an effective theory for low energy electronic excitations in bilayer graphene, in which an applied voltage between the layers ensures equal populations of particles on one layer and holes on the other. The model is then reformulated on a spacetime lattice using staggered fermions, and in the absence of a sign problem, simulated using an orthodox hybrid Monte Carlo algorithm. With the coupling strength chosen to be close to a quantum critical point believed to exist for N_fdegenerate fermion system, with a remnant Fermi surface distorted by a superfluid excitonic condensate. The model thus shows qualitatively different behaviour to any model with mu=/=0 previously studied by lattice simulation.

Wes Armour; Simon Hands; Costas Strouthos

2013-02-01T23:59:59.000Z

92

Transverse electric conductivity and dielectric permeability in quantum non-degenerate and maxwellian collisional plasma with variable collision frequency in Mermin's approach  

E-Print Network (OSTI)

Formulas for transverse conductance and dielectric permeability in quantum non-degenerate and Maxwellian collisional plasma with arbitrary variable collision frequency in Mermin's approach are deduced. Frequency of collisions of particles depends arbitrarily on a wave vector. The special case of frequency of collisions proportional to the module of a wave vector is considered. The graphic analysis of the real and imaginary parts of dielectric function is made.

Latyshev, A V

2013-01-01T23:59:59.000Z

93

The solvability of the first initial-boundary problem for parabolic and degenerate parabolic equations in domains with a conical point  

SciTech Connect

The first initial-boundary problem for second-order parabolic and degenerate parabolic equations is investigated in a domain with a conical or angular point. The means of attack is already known and uses weighted classes of smooth or integrable functions. Sufficient conditions for a unique solution to exist and for coercive estimates for the solution to be obtained are formulated in terms of the angular measure of the solid angle and the exponent of the weight. It is also shown that if these conditions fail to hold, then the parabolic problem has elliptic properties, that is, it can have a nonzero kernel or can be nonsolvable, and, in the latter case, it is not even a Fredholm problem. A parabolic equation and an equation with some degeneracy or a singularity at a conical point are considered. Bibliography: 49 titles.

Degtyarev, Sergey P [Institute of Applied Mathematics and Mechanics, Ukraine National Academy of Sciences, Donetsk (Ukraine)

2010-09-02T23:59:59.000Z

94

(L{sub e}-L{sub {mu}-}L{sub {tau}}) discrete symmetry for heavy right-handed neutrinos and degenerate leptogenesis  

Science Conference Proceedings (OSTI)

The degenerate leptogenesis is studied when the degeneracy in two of the heavy right-handed neutrinos [the third one is irrelevant if {mu}-{tau} symmetry is assumed] is due to L{identical_to}(L{sub e}-L{sub {mu}-}L{sub {tau}}) discrete symmetry. It is shown that a sizable leptogenesis asymmetry ({epsilon}{>=}10{sup -6}) is possible. The level of degeneracy required also predicts the Majorana phase needed for the asymmetry and this prediction is testable since it is the same phase, which appears in the double {beta} decay. Implications of nonzero reactor angle {theta}{sub 13} are discussed. It is shown that the contribution from sin{sup 2{theta}}{sub 13} to the leptogenesis asymmetry parameter may even dominate. An accurate measurement of sin{sup 2{theta}}{sub 13} would have important implications for the mass degeneracy of heavy right-handed neutrinos.

Riazuddin [Centre for Advanced Mathematics and Physics, National University of Sciences and Technology, Rawalpindi (Pakistan) and National Centre for Physics, Quaid-i-Azam University, Islamabad (Pakistan)

2010-05-01T23:59:59.000Z

95

Theoretical Uncertainties in the Subgiant--Mass Age Relation and the Absolute Age of Omega Cen  

E-Print Network (OSTI)

The theoretical uncertainties in the calibration of the relationship between the subgiant mass and age in metal-poor stars are investigated using a Monte Carlo approach. Assuming that the mass and iron abundance of a subgiant star are known exactly, uncertainties in the input physics used to construct stellar evolution models and isochrones lead to a Gaussian 1-sigma uncertainty of +/-2.9% in the derived ages. The theoretical error budget is dominated by the uncertainties in the calculated opacities. Observations of detached double lined eclipsing binary OGLEGC-17 in the globular cluster Omega Cen have found that the primary is on the subgiant branch with a mass of M = 0.809+/-0.012 M_sun and [Fe/H]= -2.29+/-0.15 (Kaluzny et al. 2001). Combining the theoretical uncertainties with the observational errors leads to an age for OGLEGC-17 of 11.10+/-0.67 Gyr. The one-sided, 95% lower limit to the age of OGLEGC-17 is 10.06 Gyr, while the one-sided, 95% upper limit is 12.27 Gyr.

Brian Chaboyer; Lawrence M. Krauss

2002-01-28T23:59:59.000Z

96

Exploring Age-Related Environmental Attitudes in the Context of Wood Product Certification  

E-Print Network (OSTI)

are general environmental attitudes, attitudes about the extraction and manufacturing of various resources and the processing of various building materials can predict attitudes about certification. In addition, other, the fourth section asks respondents whether or not they regard the extraction or manufacturing of certain

97

Dynamic Chromatin Localization of Sirt6 Shapes Stress-and Aging-Related Transcriptional Networks  

E-Print Network (OSTI)

control. Sirt6 can interact with the stress-responsive transcription factor NF-kB and regulate some NF-kB upon stress-signaling. The majority of genes bound by NF-kB subunit RelA recruit Sirt6, and dynamic of NF-kB signaling in stress response and aging. Citation: Kawahara TLA, Rapicavoli NA, Wu AR, Qu K

Quake, Stephen R.

98

Melatonin Alters Age-Related Changes in Transcription Factors and Kinase Activation  

E-Print Network (OSTI)

not to alter the extent of NF-kB or AP-1 activation [14]. X-in the spleen, dietary a NF-kB activity (densitometic units)YC YM OC OM b NF-kB activity (densitometic units) Results

Bondy, Stephen Bondy C

2010-01-01T23:59:59.000Z

99

Is Lutein a Physiologically Important Ligand for Transthyretin in Humans?  

SciTech Connect

Lutein and zeaxanthin are the only carotenoids accumulated in the macula of the human retina and are known as the macular pigments (MP). These pigments account for the yellow color of the macula and appear to play an important role in protecting against age-related macular degeneration (AMD). The uptake of lutein and zeaxanthin in human eyes is remarkably specific. It is likely that specific transport or binding proteins are involved. The objective is to determine whether transthyretin (TTR) is a transport protein in human plasma and could thus deliver lutein from the blood to the retina. In this study, they used a biosynthetic {sup 13}C-lutein tracer and gas chromatography-combustion interfaced-isotope ratio mass spectrometry (GCC-IRMS) to gain the requisite sensitivity to detect the minute amounts of lutein expected as a physiological ligand for human transthyretin. The biosynthetic {sup 13}C-labeled lutein tracer was purified from algae. Healthy women (n = 4) each ingested 1 mg of {sup 13}C-labeled lutein daily for 3 days and a blood sample was collected 24 hours after the final dose. Plasma TTR was isolated by retinol-binding protein (RBP)-sepharose affinity chromatography and extracted with chloroform. The {sup 13}C/{sup 12}C ratio in the TTR extract was measured by GCC-IRMS. There was no {sup 13}C-lutein enrichment in the pure TTR extract. This result indicated that lutein is not associated with TTR in human plasma after ingestion in physiological amounts. Some hydrophobic compounds with yellow color may bind to human TTR in the plasma. However, this association needs to be further proved by showing specificity. The study provides a new approach for carotenoid-binding protein studies using a stable isotope tracer method combined with the high precision of GCC-IRMS. The mechanism of selective transport, uptake, and accumulation of lutein in human macula remain to be determined.

Liwei Chen

2003-05-31T23:59:59.000Z

100

Electrical and optical properties of degenerately doped N-type In{sub x}Ga{sub 1{minus}x}As  

DOE Green Energy (OSTI)

Degenerately-doped (> 10{sup 19} cm{sup {minus}3}) n-type In{sub x}Ga{sub 1{minus}x}As (x > 0.53) possesses a number of intriguing electrical and optical properties relevant to electro-optic devices and thermophotovoltaic devices in particular. Due to the low electron effective mass of this material and the demonstrated ability to incorporate n-type dopants into the mid-10{sup 19} cm{sup {minus}3} range, both the Moss-Burnstein bandgap shift and plasma reflection characteristics are particularly dramatic. These properties are investigated for In{sub x}Ga{sub 1{minus}x}As as a function of doping concentration, dopant type, and growth conditions. For undoped InGaAs with a nominal bandgap of 0.6 eV, doping this material to 5 {times} 10{sup 19} cm{sup {minus}3} increased the effective optical bandgap to 1.1 eV and has a plasma turn-on wavelength of 5 microns. This filter was coupled to a non-absorbing interference filter, creating a functional tandem filter for thermophotovoltaic applications.

Charache, G.W.; DePoy, D.M.; Egley, J.L. [Lockheed Martin, Inc., Schenectady, NY (United States)] [and others

1997-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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101

Theoretical prediction of the plasma frequency and Moss-Burstein shifts for degenerately doped In{sub x}Ga{sub 1{minus}x}As  

DOE Green Energy (OSTI)

Theoretical predictions for the plasma frequency and Moss-Burstein shift (optical band gap) of degenerately doped (n > 10{sup 19} cm{sup {minus}3}) In{sub x}Ga{sub 1{minus}x} As are presented. This system is of interest because it possesses desirable optical properties for thermophotovoltaic (TPV) applications. The studies presented are based on electronic band structures calculated using the Full Potential Linearized Augmented Plane Wave (FLAPW) method which includes non-local screened exchange (sX-LDA) and spin-orbit effects. The plasma frequency and Moss-Burstein shift are calculated vs. doping assuming a rigid band approximation (i.e. conduction band filling of the undoped bands). The doping dependence of the effective mass (band non-parabolicity) plays an important role at the high dopings considered here. This effect leads to a maximum in the plasma frequency vs. doping (2--3 {times} 10{sup 14}/s) and a significant departure from the constant effective mass prediction for the optical band gap vs. doping. These calculations are in good agreement with measurements.

Raynolds, J.E.; Charache, G.W. [Lockheed Martin Corp., Schenectady, NY (United States); Geller, C.B. [Bettis Atomic Power Lab., West Mifflin, PA (United States); Holden, T.; Pollak, F.H. [City Univ. of New York, Brooklyn, NY (United States)

1998-10-01T23:59:59.000Z

102

Investigations of the Biological Roles of Substituted Cyclohexadienes  

E-Print Network (OSTI)

In recent years there have been two cycloterpenals, molecules consisting of a cyclohexadienal core, isolated from nature. Cyclocitral, the condensation product of citral, has been isolated from the North Sea bryozoans Flustra foliacea. In the human eyes, cycloretinal has been isolated and is a toxic by product of the vision cycle. This retinal dimer is believed to contribute to age related macular degeneration, the leading cause of blindness in the elderly. In 1992, it was discovered that if [beta]-ionylideneacetaldehyde was incubated with beta-lactoglobulin ([beta]-LG), the principal whey protein in dairy milk, that it would mediate the formation of cyclo-[beta]-ional. No follow up studies were performed on this protein mediated reaction or what biological activities these cycloterpenals may possess. This dissertation investigates the biological roles of substituted cyclohexadienes including cycloterpenals and cyclohexadiene enaminonitriles. To mimic the protein mediated reaction, we developed a synthetic procedure to produce a wide array of cycloterpenal by utilizing L-proline. Over 100 cycloterpenals were synthesized and screened for their biological activities against an array of cell based screens. The phenotypic effects of these cycloterpenals were screened against a PC12 assay where dramatic effects were observed on neurite outgrowth. During the synthesis of starting materials for the production of our cycloterpenal library, it was discovered that if excess base was added to the Horner-Wadsworth-Emmons reaction between a methyl-ketone and diethyl-(cyanomethyl)-phosphonate, conversion of the [alpha]-[beta]-unsaturated nitrile into an enaminonitrile was observed. This new synthetic procedure was optimized to generate a library of enaminonitriles as well as their quinazoline derivatives. The work within also includes the investigation of the [beta]-LG mediated reaction formation of cycloterpenals with natural and unnatural [beta]-methyl aldehydes. We were able to demonstrate that [beta]-LG could mediate the conversion of [alpha],[beta]-unsaturated aldehydes into their corresponding cycloterpenal. In vitro analysis was also performed with store bought milks and the [beta]-LG present was able to mediate the formation of cyclocitral. An in vivo experiment was also performed by utilizing New Zealand White rabbits to demonstrate the formation of cycloretinal within the blood stream by feeding a source of [beta]-LG with retinal. Interestingly, in human blood, [beta]-LG is present at concentrations of 0.7-1.2 g/dL. The protein has been identified within drusen pigments and lipofuscin granules that accumulate in the retina of macular degeneration patients. As humans do not produce beta-lactoglobulin, the source of this protein is from milk and milk products. With these experiments, we clearly demonstrate that under the appropriate conditions, cycloretinal can be produced with [beta]-LG. We have clearly established a direct link between [beta]-LG chemistry and age-related macular degeneration.

Bench, Bennie John

2009-12-01T23:59:59.000Z

103

How the Artificial Retina Works  

NLE Websites -- All DOE Office Websites (Extended Search)

the Artificial Retina Works the Artificial Retina Works Artificial Retina Diagram Normal vision begins when light enters and moves through the eye to strike specialized photoreceptor (light-receiving) cells in the retina called rods and cones. These cells convert light signals to electric impulses that are sent to the optic nerve and the brain. Retinal diseases like age-related macular degeneration and retinitis pigmentosa destroy vision by annihilating these cells. With the artificial retina device, a miniature camera mounted in eyeglasses captures images and wirelessly sends the information to a microprocessor (worn on a belt) that converts the data to an electronic signal and transmits it to a receiver on the eye. The receiver sends the signals through a tiny, thin cable to the microelectrode array, stimulating it to emit pulses. The artificial retina device thus bypasses defunct photoreceptor cells and transmits electrical signals directly to the retina's remaining viable cells. The pulses travel to the optic nerve and, ultimately, to the brain, which perceives patterns of light and dark spots corresponding to the electrodes stimulated. Patients learn to interpret these visual patterns.

104

Degenerate states in language - CECM  

E-Print Network (OSTI)

Dec 24, 2003 ... Attenuation can also be considered in terms of energy level. ... this fact, we say that attenuation levels are unevenly distributed across vocables.

105

AN ALGORITHM FOR DEGENERATE NONLINEAR ...  

E-Print Network (OSTI)

0 ? g(z?) ? ?? ? 0,. (1.3b). *Computer Sciences Department, University of Wisconsin, 1210 W. Dayton Street, Madison, WI. 53706, USA; swright@cs.wisc. edu.

106

Degenerating behavior of Green's function  

E-Print Network (OSTI)

Let the unions of real intervals $I = \\cup_{j = 1}^l [a_{2 j -1},a_{2j}],$ $a_1 0.$ We show how to express asymptotically the Green's function $\\phi(z,\\infty,E \\cup I_n)$ of $E \\cup I_n$ at $z = \\infty$ in terms of the Green's function $\\phi(z,\\infty,E)$ and $\\phi(z,c_k,E).$ The formula yields immediately asymptotics for $\\phi^n(z,\\infty,E \\cup I_n)$ with respect to $n$ which are important in many problems of approximation theory. Another consequence is an asymptotic representation of $cap(E \\cup I_n)$ in terms of $cap(E)$ and $\\phi(z,c_k,E)$ and of the harmonic measure $\\omega(\\infty, E_j,E \\cup I_n).$

Peherstorfer, Franz

2010-01-01T23:59:59.000Z

107

Review of Recent Aging-Related Degradation Occurrences of Structures and Passive Components in U.S. Nuclear Power Plants  

Science Conference Proceedings (OSTI)

The Korea Atomic Energy Research Institute (KAERI) and Brookhaven National Laboratory (BNL) are collaborating to develop seismic capability evaluation technology for degraded structures and passive components (SPCs) under a multi-year research agreement. To better understand the status and characteristics of degradation of SPCs in nuclear power plants (NPPs), the first step in this multi-year research effort was to identify and evaluate degradation occurrences of SPCs in U.S. NPPs. This was performed by reviewing recent publicly available information sources to identify and evaluate the characteristics of degradation occurrences and then comparing the information to the observations in the past. Ten categories of SPCs that are applicable to Korean NPPs were identified, comprising of anchorage, concrete, containment, exchanger, filter, piping system, reactor pressure vessel, structural steel, tank, and vessel. Software tools were developed to expedite the review process. Results from this review effort were compared to previous data in the literature to characterize the overall degradation trends.

Nie,J.; Braverman, J.; Hofmayer, C.; Choun, Y.-S.; Kim, M.K.; Choi, I.-K.

2009-04-02T23:59:59.000Z

108

THE POST-MERGER MAGNETIZED EVOLUTION OF WHITE DWARF BINARIES: THE DOUBLE-DEGENERATE CHANNEL OF SUB-CHANDRASEKHAR TYPE Ia SUPERNOVAE AND THE FORMATION OF MAGNETIZED WHITE DWARFS  

SciTech Connect

Type Ia supernovae (SNe Ia) play a crucial role as standardizable cosmological candles, though the nature of their progenitors is a subject of active investigation. Recent observational and theoretical work has pointed to merging white dwarf binaries, referred to as the double-degenerate channel, as the possible progenitor systems for some SNe Ia. Additionally, recent theoretical work suggests that mergers which fail to detonate may produce magnetized, rapidly rotating white dwarfs. In this paper, we present the first multidimensional simulations of the post-merger evolution of white dwarf binaries to include the effect of the magnetic field. In these systems, the two white dwarfs complete a final merger on a dynamical timescale, and are tidally disrupted, producing a rapidly rotating white dwarf merger surrounded by a hot corona and a thick, differentially rotating disk. The disk is strongly susceptible to the magnetorotational instability (MRI), and we demonstrate that this leads to the rapid growth of an initially dynamically weak magnetic field in the disk, the spin-down of the white dwarf merger, and to the subsequent central ignition of the white dwarf merger. Additionally, these magnetized models exhibit new features not present in prior hydrodynamic studies of white dwarf mergers, including the development of MRI turbulence in the hot disk, magnetized outflows carrying a significant fraction of the disk mass, and the magnetization of the white dwarf merger to field strengths {approx}2 Multiplication-Sign 10{sup 8} G. We discuss the impact of our findings on the origins, circumstellar media, and observed properties of SNe Ia and magnetized white dwarfs.

Ji Suoqing; Fisher, Robert T. [University of Massachusetts Dartmouth, Department of Physics, 285 Old Westport Road, North Dartmouth, MA 02740 (United States); Garcia-Berro, Enrique [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, c/Esteve Terrades, 5, E-08860 Castelldefels (Spain); Tzeferacos, Petros; Jordan, George; Lee, Dongwook [Center for Astrophysical Thermonuclear Flashes, The University of Chicago, Chicago, IL 60637 (United States); Loren-Aguilar, Pablo [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Cremer, Pascal [Bethe Center for Theoretical Physics, Universitaet Bonn, Nussallee 12, D-53115 Bonn (Germany); Behrends, Jan [Fachbereich Physik, Freie Universitaet Berlin, Arnimallee 14, D-14195 Berlin (Germany)

2013-08-20T23:59:59.000Z

109

Preprocessing and Reduction for Degenerate Semidefinite Programs  

E-Print Network (OSTI)

Feb 18, 2011 ... original problem does not satisfy Slater's condition, then one single ...... 413 the only solution6. Therefore, Q from Corollary 4.2 must have n ? 1...

110

Some New Aspects of Degenerate Quantum Plasma  

Science Conference Proceedings (OSTI)

Answers to some salient questions, which arise in quantum plasmas, are given. Starting from the Schroedinger equation for a single particle it is demonstrated how the Wigner-Moyal equation can be derived. It is shown that the Wigner-Moyal type of equation also exists in the classical field theory. As an example, from the Maxwell equations the Wigner-Moyal type of equation is obtained for a dense photon gas, which is classical, concluding that the Wigner-Moyal type of equation can be derived for any system, classical or quantum. A new type of quantum kinetic equations are presented. These novel kinetic equations allows to obtain a set of quantum hydrodynamic equations, which is impossible to derive by the Wigner-Moyal equation. The propagation of small perturbations and instabilities of these perturbations are then discussed, presenting new modes of quantum plasma waves. In the case of low frequency oscillations with ions, a new Bogolyubov type of spectrum is found. Furthermore, the Korteweg-de Vries (KdV) equation is derived and the contribution of the Madelung term in the formation of the KdV solitons is discussed.

Tsintsadze, Nodar L. [Department of Plasma Physics, E. Andronikashvii Institute of Physics, Tbilisi (Georgia)

2010-12-14T23:59:59.000Z

111

CAPELLI IDENTITIES, DEGENERATE SERIES AND HYPERGEOMETRIC FUNCTIONS*  

E-Print Network (OSTI)

______________* A talk on a symposium on Representation Theory held at Okinawa, December 12* *-15, 1995. y

Oshima, Toshio

112

Optimization Online - An Algorithm for Degenerate Nonlinear ...  

E-Print Network (OSTI)

Citation: Optimization Technical Report 03-02, Computer Sciences Department, University of Wisconsin-Madison, September 2003. Modified April 2004.

113

Magnetoacoustic shock waves in dissipative degenerate plasmas  

SciTech Connect

Quantum magnetoacoustic shock waves are studied in homogenous, magnetized, dissipative dense electron-ion plasma by using two fluid quantum magneto-hydrodynamic (QMHD) model. The weak dissipation effects in the system are taken into account through kinematic viscosity of the ions. The reductive perturbation method is employed to derive Korteweg-de Vries Burgers (KdVB) equation for magnetoacoustic wave propagating in the perpendicular direction to the external magnetic field in dense plasmas. The strength of magnetoacoustic shock is investigated with the variations in plasma density, magnetic field intensity, and ion kinematic viscosity of dense plasma system. The necessary condition for the existence of monotonic and oscillatory shock waves is also discussed. The numerical results are presented for illustration by using the data of astrophysical dense plasma situations such as neutron stars exist in the literature.

Hussain, S.; Mahmood, S. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P.O. Nilore Islamabad 44000 (Pakistan) and Department of Physics and Applied Mathematics (DPAM) PIEAS, P.O. Nilore Islamabad 44000 (Pakistan)

2011-11-15T23:59:59.000Z

114

Natural Product Biosynthesis: Friend or Foe? From Anti-tumor Agent to Disease Causation  

E-Print Network (OSTI)

Biosynthetic natural products are invaluable resources that have been gleaned from the environment for generations, and they play an essential role in drug development. Natural product biosynthesis also possesses the latent ability to affect biological systems adversely. This work implements recent advances in genomic, proteomic and microbiological technologies to understand further biosynthetic molecules that may influence progression of human disease. Azinomycin A and B are antitumor metabolites isolated from the terrestrial bacterium Streptomyces sahachiroi. The azinomycins possess an unusual aziridine [1,2-a] pyrrolidine ring that reacts in concert with an epoxide moiety to produce DNA interstrand cross-links. Genomic sequencing of S. sahachiroi revealed a putative azinomycin resistance protein (AziR). Overexpression of AziR in heterologous hosts demonstrated the protein increases cell viability and decreases DNA damage response in the presence of azinomycin. Fluorescence titration indicated AziR functions as an azinomycin binding protein. An understanding of azinomycin resistance is important for future engineering and drug delivery strategies. Additionally, the S. sahachiroi draft genome obtained via 454 pyrosequencing and Illumina sequencing revealed several silent secondary metabolic pathways that may provide new natural products with biomedical application. ?-lactoglobulin (BLG), the most abundant whey protein in bovine milk, has been observed to promote the self-condensation of retinal and similar ?,?-unsaturated aldehydes. BLG is a possible non-genetic instigator of cycloretinal and A2E accumulation in the macula, a condition associated with age-related macular degeneration. BLG-mediated terpenal condensation has been optimized for in vitro study with the retinal mimic citral. In rabbits fed retinal and BLG or skim milk, cycloretinal formation was detected in the blood by 1H-NMR, and SDS-PAGE analysis indicated BLG was present in blood serum, suggesting the protein survives ingestion and retains catalytic activity. Mass spectrometry and site-directed mutagenesis provided mechanistic insight toward this unusual moonlighting behavior. The experiments described in this dissertation serve to further natural product biosynthesis discovery and elucidation as they relate to consequences for human health. Efforts to solve azinomycin biosynthesis via enzymatic reconstitution, characterize compounds produced by orphan gene clusters within S. sahachiroi, and obtain a clear mechanism for BLG-promoted cycloterpenal formation are immediate goals within the respective projects.

Foulke-Abel, Jennifer

2010-12-01T23:59:59.000Z

115

Generation of degenerate, factorizable, pulsed squeezed light at telecom wavelengths  

SciTech Connect

We characterize a periodically poled KTP crystal that produces an entangled, two-mode, squeezed state with orthogonal polarizations, nearly identical, factorizable frequency modes, and few photons in unwanted frequency modes. We focus the pump beam to create a nearly circular joint spectral probability distribution between the two modes. After disentangling the two modes, we observe Hong-Ou-Mandel interference with a raw (background corrected) visibility of 86% (95%) when an 8.6 nm bandwidth spectral filter is applied. We measure second order photon correlations of the entangled and disentangled squeezed states with both superconducting nanowire single-photon detectors and photon-number-resolving transition-edge sensors. Both methods agree and verify that the detected modes contain the desired photon number distributions.

Gerrits, Thomas [National Institute of Standards and Technology (NIST), Boulder; Stevens, Martin [National Institute of Standards and Technology (NIST), Boulder; Baek, Burm [National Institute of Standards and Technology (NIST), Boulder; Calkins, Brice [National Institute of Standards and Technology (NIST), Boulder; Lita, Adriana [National Institute of Standards and Technology (NIST), Boulder; Glancy, Scott [National Institute of Standards and Technology (NIST), Boulder; Knill, Emanuel [National Institute of Standards and Technology (NIST), Boulder; Nam, Sae Woo [National Institute of Standards and Technology (NIST), Boulder; Mirin, Richard [National Institute of Standards and Technology (NIST), Boulder; Hadfield, Robert [Heriot-Watt University, Edinburgh; Bennink, Ryan S [ORNL; Grice, Warren P [ORNL; Dorenbos, Sander [Delft University of Technology, Delft, Netherlands; Zijlstra, Tony [Delft University of Technology, Delft, Netherlands; Klapwijk, Teun [Delft University of Technology, Delft, Netherlands; Zwiller, Val [Delft University of Technology, Delft, Netherlands

2011-01-01T23:59:59.000Z

116

Properties of Hubbard models with degenerate localized single particle eigenstates  

E-Print Network (OSTI)

We consider the repulsive Hubbard model on a class of lattices or graphs for which there is a large degeneracy of the single particle ground states and where the projector onto the space of single particle ground states is highly reducible. This means that one can find a basis in the space of the single particle ground states such that the support of each single particle ground state belongs to some small cluster and these clusters do not overlap. We show how such lattices can be constructed in arbitrary dimensions. We construct all multi-particle ground states of these models for electron numbers not larger than the number of localized single particle eigenstates. We derive some of the ground state properties, esp. the residual entropy, i.e. the finite entropy density at zero temperature.

Andreas Mielke

2012-02-14T23:59:59.000Z

117

The Shifted Peak: Resolvng Nearly Degenerate Particles at the LHC  

E-Print Network (OSTI)

work by Cheng and Han. Their proof that mT2 admits an equivalent, but implicit, definition as the boundary of the region of parent and daughter masses that is kinematically consistent with the event hypothesis is far-reaching in its consequences. We... in the definition is lost, gives rise to a strange kink behaviour. What does all of this mean? Recently, Cheng and Han, gave an elegant interpreta- tion of the function mT2(mi) [47].4 They showed that, for a given event, it defines the boundary of the region...

Feng, Jonathan; French, Sky; Lester, Christopher G; Nir, Yosef; Shadmi, Yael

2009-01-01T23:59:59.000Z

118

Row-Reduced Column Generation for Degenerate Master Problems  

E-Print Network (OSTI)

Feb 5, 2013 ... node of a search tree, and often produces strong dual bounds. ... In linear algebra terms, we work with a projection ... enter the current basis.

119

EARLY REMODELING IN AN INDUCIBLE ANIMAL MODEL OF RETINAL DEGENERATION  

E-Print Network (OSTI)

fluoride membrane (MDI Membrane Technologies, Ambala, India). The blot was incubated at room temperature

Dhingra, Narender K.

120

1  

NLE Websites -- All DOE Office Websites (Extended Search)

Lab team makes unique contributions to Lab team makes unique contributions to the first bionic eye June 27, 2013 As part of the multi-institutional Artificial Retina Project, Los Alamos researchers helped develop the first bionic eye. Recently approved by the U.S. Food and Drug Administration, the Argus II will help people blinded by the rare hereditary disease retinitis pigmentosa or seniors suffering from severe macular degeneration-diseases that destroy the light-sensing cell in the retina. Los Alamos scientists served as the Advanced Concepts team, focusing on fundamental issues and out-of the box ideas. Significance of the research The Argus II operates by using a miniature camera mounted in eyeglasses that captures images and wirelessly sends the information to a microprocessor (worn on a belt) that converts the data to an electronic signal. Pulses from an electrode

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Data embedding employing degenerate clusters of data having differences less than noise value  

DOE Patents (OSTI)

A method of embedding auxiliary information into a set of host data, such as a photograph, television signal, facsimile transmission, or identification card. All such host data contain intrinsic noise, allowing pixels in the host data which are nearly identical and which have values differing by less than the noise value to be manipulated and replaced with auxiliary data. As the embedding method does not change the elemental values of the host data, the auxiliary data do not noticeably affect the appearance or interpretation of the host data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user.

Sanford, II, Maxwell T. (Los Almos, NM); Handel, Theodore G. (Los Almos, NM)

1998-01-01T23:59:59.000Z

122

155- Degenerate Pearlite and MA Constituent Formation in the ...  

Science Conference Proceedings (OSTI)

086- Improvement in Gas Tightness of YSZ Coatings Produced by Atmospheric Plasma ... 145- The Synergy of XRD and XRF in a Shale and Slate Analysis.

123

Hydrostatic Equilibrium with Degenerate Fermions, Type-II Supernova, and Neutrino Burst  

E-Print Network (OSTI)

much less than free charged particles do. In particular, the existing blackbody radiation of photons

Murayama, Hitoshi

124

Transverse electric conductivity in quantum degenerate collisional plasma in Mermin approach  

E-Print Network (OSTI)

Formulas for transverse conductance in quantum collisional plasma are deduced. The kinetic equation in momentum space in the relaxation approach is used. It is shown, that at Planck's constant tends to zero the derived formula transfers to the classical one. It is shown also, that when electron collision frequency tends to null (i.e. plasma becomes collisionless), the conductance formula transfers in the known formula inferred earlier by Lindhard.

A. V. Latyshev; A. A. Yushkanov

2012-07-16T23:59:59.000Z

125

Transverse electric conductivity in quantum degenerate collisional plasma in Mermin approach  

E-Print Network (OSTI)

Formulas for transverse conductance in quantum collisional plasma are deduced. The kinetic equation in momentum space in the relaxation approach is used. It is shown, that at Planck's constant tends to zero the derived formula transfers to the classical one. It is shown also, that when electron collision frequency tends to null (i.e. plasma becomes collisionless), the conductance formula transfers in the known formula inferred earlier by Lindhard.

Latyshev, A V

2012-01-01T23:59:59.000Z

126

Nonlinear optical properties of porphyrin and chlorophyll dimers studied by degenerated four wave mixing  

Science Conference Proceedings (OSTI)

As one of the important elements in natural and artificial electron transfer and energy transfer processes, porphyrin and its derivatives have received much attention in photoelectronics and photoelectronic materials. As our first attempt to relate the {pi}-{pi} electronic couplings between porphyrin macrocycles to apparent third order nonlinear susceptibilities, we measured {chi}({sup 3}) for several porphyrin and chlorophyll a derivatives, including dimers with different configurations. Our preliminary results show that the dimers have enhanced {chi}({sup 3}) compared to those of the monomer. This enhancement is related to the relative orientations between the two macrocycles in the dimers. The parallel dimers with close face-to-face distances seem to have the highest enhancement in {chi}({sup 3}). Thus, we believe that {chi}({sup 3}) is strongly related to the {pi}-{pi} electronic coupling between the two conjugated ring systems.

Chen, L.X.Q.

1992-12-31T23:59:59.000Z

127

Nonlinear optical properties of porphyrin and chlorophyll dimers studied by degenerated four wave mixing  

SciTech Connect

As one of the important elements in natural and artificial electron transfer and energy transfer processes, porphyrin and its derivatives have received much attention in photoelectronics and photoelectronic materials. As our first attempt to relate the [pi]-[pi] electronic couplings between porphyrin macrocycles to apparent third order nonlinear susceptibilities, we measured [chi]([sup 3]) for several porphyrin and chlorophyll a derivatives, including dimers with different configurations. Our preliminary results show that the dimers have enhanced [chi]([sup 3]) compared to those of the monomer. This enhancement is related to the relative orientations between the two macrocycles in the dimers. The parallel dimers with close face-to-face distances seem to have the highest enhancement in [chi]([sup 3]). Thus, we believe that [chi]([sup 3]) is strongly related to the [pi]-[pi] electronic coupling between the two conjugated ring systems.

Chen, L.X.Q.

1992-01-01T23:59:59.000Z

128

Data embedding employing degenerate clusters of data having differences less than noise value  

DOE Patents (OSTI)

A method of embedding auxiliary information into a set of host data, such as a photograph, television signal, facsimile transmission, or identification card. All such host data contain intrinsic noise, allowing pixels in the host data which are nearly identical and which have values differing by less than the noise value to be manipulated and replaced with auxiliary data. As the embedding method does not change the elemental values of the host data, the auxiliary data do not noticeably affect the appearance or interpretation of the host data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. 35 figs.

Sanford, M.T. II; Handel, T.G.

1998-10-06T23:59:59.000Z

129

A COMPACT DEGENERATE PRIMARY-STAR PROGENITOR OF SN 2011fe  

Science Conference Proceedings (OSTI)

While a white dwarf (WD) is, from a theoretical perspective, the most plausible primary star of a Type Ia supernova (SN Ia), many other candidates have not been formally ruled out. Shock energy deposited in the envelope of any exploding primary contributes to the early SN brightness and, since this radiation energy is degraded by expansion after the explosion, the diffusive luminosity depends on the initial primary radius. We present a new non-detection limit of the nearby SN Ia 2011fe, obtained at a time that appears to be just 4 hr after explosion, allowing us to directly constrain the initial primary radius (R{sub p} ). Coupled with the non-detection of a quiescent X-ray counterpart and the inferred synthesized {sup 56}Ni mass, we show that R{sub p} {approx} 10{sup 4} g cm{sup -3}, and that the effective temperature must be less than a few Multiplication-Sign 10{sup 5} K. This rules out hydrogen-burning main-sequence stars and giants. Constructing the helium-burning and carbon-burning main sequences, we find that such objects are also excluded. By process of elimination, we find that only degeneracy-supported compact objects-WDs and neutron stars-are viable as the primary star of SN 2011fe. With few caveats, we also restrict the companion (secondary) star radius to R{sub c} {approx}< 0.1 R{sub Sun }, excluding Roche-lobe overflowing red giant and main-sequence companions to high significance.

Bloom, Joshua S.; Kasen, Daniel; Shen, Ken J.; Nugent, Peter E. [Department of Astronomy, University of California, Berkeley, Berkeley CA, 94720-3411 (United States); Butler, Nathaniel R. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States); Graham, Melissa L.; Andrew Howell, D. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102, Goleta, CA 93117 (United States); Kolb, Ulrich; Holmes, Stefan; Haswell, Carole A. [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Burwitz, Vadim [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Rodriguez, Juan [Observatori Astronomic de Mallorca, Cami de l'Observatori, 07144 Costitx, Mallorca (Spain); Sullivan, Mark, E-mail: jbloom@astro.berkeley.edu [Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)

2012-01-10T23:59:59.000Z

130

Free fermion antibunching in a degenerate atomic Fermi gas released from an optical lattice  

E-Print Network (OSTI)

Noise in a quantum system is fundamentally governed by the statistics and the many-body state of the underlying particles. Whereas for bosonic particles the correlated noise observed for e.g. photons or bosonic neutral atoms can still be explained within a classical field description with fluctuating phases, the anticorrelations in the detection of fermionic particles have no classical analogue. The observation of such fermionic antibunching is so far scarce and has been confined to electrons and neutrons. Here we report on the first direct observation of antibunching of neutral fermionic atoms. Through an analysis of the atomic shot noise in a set of standard absorption images, of a gas of fermionic 40K atoms released from an optical lattice, we find reduced correlations for distances related to the original spacing of the trapped atoms. The detection of such quantum statistical correlations has allowed us to characterise the ordering and temperature of the Fermi gas in the lattice. Moreover, our findings are an important step towards revealing fundamental fermionic many-body quantum phases in periodic potentials, which are at the focus of current research.

T. Rom; Th. Best; D. van Oosten; U. Schneider; S. Foelling; B. Paredes; I. Bloch

2006-11-21T23:59:59.000Z

131

Magnetic susceptibility and Landau diamagnetism of a quantum collisional Plasmas with arbitrary degree of degeneration of electronic gas  

E-Print Network (OSTI)

The kinetic description of magnetic susceptibility and Landau diamagnetism of quantum collisional plasmas with any degeration of electronic gas is given. The correct expression of electric conductivity of quantum collisional plasmas with any degeration of electronic gas (see A. V. Latyshev and A. A. Yushkanov, Transverse electrical conductivity of a quantum collisional plasma in the Mermin approach. - Theor. and Math. Phys., V. 175(1):559-569 (2013)) is used.

Latyshev, A V

2013-01-01T23:59:59.000Z

132

Structural brain changes in first episode Schizophrenia compared with Fronto-Temporal Lobar Degeneration: a meta-analysis  

E-Print Network (OSTI)

. Ellison-Wright I, Glahn DC, Laird AR, Thelen SM, Bullmore E: The anatomy of first-episode and chronic schizophrenia: an anatomical likelihood estimation meta-analysis. Am J Psychiatry 2008, 165(8):101523. 2. Keshavan MS, Tandon R, Boutros NN, Nasrallah HA...

Olabi, Bayanne; Ellison-Wright, Ian; Bullmore, Ed; Lawrie, Stephen M

2012-08-07T23:59:59.000Z

133

Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation Oxidative Stress and Skeletal Health with Low Dose, Ionizing Radiation Globus Ruth NASA Ames Research Center Abstract Osteoporosis profoundly affects the aging U.S. population and exposure to high doses of radiation causes bone loss similar to age-related osteoporosis, although the influence of low dose radiation exposures is not known. The central hypothesis of our DOE project (NASA supplement) is that low doses of radiation modulate subsequent skeletal degeneration via oxidative pathways. Our working hypothesis is that a prior exposure to low dose radiation regulates oxidative metabolism within bone and contributes to bone loss caused either by subsequent high, challenge doses of radiation or by aging. HZE source: Because astronauts are exposed to radiation from GCR and solar

134

About the Artificial Retina Project  

NLE Websites -- All DOE Office Websites (Extended Search)

Overview of the Overview of the Artificial Retina Project The DOE Artificial Retina Project was a multi-institutional collaborative effort to develop and implant a device containing an array of microelectrodes into the eyes of people blinded by retinal disease. The ultimate goal was to design a device to help restore limited vision that enables reading, unaided mobility, and facial recognition. The device is intended to bypass the damaged eye structure of those with retinitis pigmentosa and macular degeneration. These diseases destroy the light-sensing cells (photoreceptors, or rods and cones) in the retina, a multilayered membrane located at the back of the eye. For more information, see How the Artificial Retina Works. History The DOE project builds on the foundational work of its leader, Mark Humayun at the Doheny Eye Institute of the University of Southern California. In a breakthrough operation performed in 2002, a team led by Humayun successfully implanted the first device of its kind-an array containing 16 microelectrodes-into the eye of a patient who had been blind for more than 50 years. Since then, more than 30 additional volunteers around the world have had first- or second-generation (60-electrode) devices implanted. These devices enable patients to distinguish light from dark and localize large objects. For more information, read patient stories.

135

EVALUATING SYSTEMATIC DEPENDENCIES OF TYPE Ia SUPERNOVAE: THE INFLUENCE OF CENTRAL DENSITY  

SciTech Connect

We present a study exploring a systematic effect on the brightness of Type Ia supernovae using numerical models that assume the single-degenerate paradigm. Our investigation varied the central density of the progenitor white dwarf at flame ignition, and considered its impact on the explosion yield, particularly the production and distribution of radioactive {sup 56}Ni, which powers the light curve. We performed a suite of two-dimensional simulations with randomized initial conditions, allowing us to characterize the statistical trends that we present. The simulations indicate that the production of Fe-group material is statistically independent of progenitor central density, but the mass of stable Fe-group isotopes is tightly correlated with central density, with a decrease in the production of {sup 56}Ni at higher central densities. These results imply that progenitors with higher central densities produce dimmer events. We provide details of the post-explosion distribution of {sup 56}Ni in the models, including the lack of a consistent centrally located deficit of {sup 56}Ni, which may be compared to observed remnants. By performing a self-consistent extrapolation of our model yields and considering the main-sequence lifetime of the progenitor star and the elapsed time between the formation of the white dwarf and the onset of accretion, we develop a brightness-age relation that improves our prediction of the expected trend for single degenerates and we compare this relation with observations.

Krueger, Brendan K.; Jackson, Aaron P.; Calder, Alan C. [Department of Physics and Astronomy, State University of New York-Stony Brook, Stony Brook, NY (United States); Townsley, Dean M. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL (United States); Brown, Edward F. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI (United States); Timmes, Francis X., E-mail: brendan.krueger@stonybrook.edu [Joint Institute for Nuclear Astrophysics, Notre Dame, IN (United States)

2012-10-01T23:59:59.000Z

136

A Study on the Pointwise Time-Space Estimates of Fundamental Solution for Higher Order Schr\\odinger Equation Whose Symbol Function is One Kind of Degenerate Polynomial  

E-Print Network (OSTI)

In this paper we investigated the point-wise time-space estimates of the fundamental solution for higher order Schr\\"odinger equation. These estimates improve the result of Yao [2] and generalize the one of Cui [1].

Myong-Jin Kim; Jin-Myong Kim

2013-03-20T23:59:59.000Z

137

Fusion Rules of the Lowest Weight Representations of osp_q(1|2) at Roots of Unity: Polynomial Realization and Degeneration at Roots of Unity  

E-Print Network (OSTI)

The degeneracy of the lowest weight representations of the quantum superalgebra $osp_q(1|2)$ and their tensor products at exceptional values of %when deformation parameter $q$ takes exceptional values is studied. The main features of the structures of the finite dimensional lowest weight representations and their fusion rules are illustrated using realization of group generators as finite-difference operators acting in the space of the polynomials. The complete fusion rules for the decompositions of the tensor products at roots of unity are presented. The appearance of indecomposable representations in the fusions is described using Clebsh-Gordan coefficients derived for general values of $q$ and at roots of unity.

D. Karakhanyan; Sh. Khachatryan

2006-02-08T23:59:59.000Z

138

NERSC/DOE FES Requirements Workshop Worksheet - Alex Friedman  

NLE Websites -- All DOE Office Websites (Extended Search)

non-degenerate material and degenerate, between ionized and neutral, between liquid and vapor. To understand and simulate the results of experiments that volumetrically heat...

139

Mechanical injury and inflammatory cytokines affect cartilage integrity and tissue homeostasis : a mass spectrometric analysis of proteins with relevance to arthritis  

E-Print Network (OSTI)

Osteoarthritis is characterized by synovial joint degeneration, and its cardinal pathological feature is degeneration and loss of the articular cartilage joint surface. While the aetiology of osteoarthritis is unknown, ...

Stevens, Anna L. (Anna Lea)

2006-01-01T23:59:59.000Z

140

Active learning based intervertebral disk classification combining shape and texture similarities  

Science Conference Proceedings (OSTI)

We consider the problem of the computer aided diagnosis on intervertebral disk degeneration in this paper, where a framework of classifying the disks into healthy and degenerated groups is proposed. First, we propose to separately model the shape and ... Keywords: Active learning, Computer aided diagnosis, Intervertebral disk degeneration, Shape, Texture

Shijie Hao; Jianguo Jiang; Yanrong Guo; Hong Li

2013-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Analysis of a Bucketwheel Stacker Reclaimer Structural Failure  

Science Conference Proceedings (OSTI)

... with Failure Investigations and Age Related Degradation Mechanisms in the Materials and Manufacturing Selection for the New AP1000 Nuclear Power Plant

142

LA LEYENDA DE LOS SIETE INFANTES DE SALAS Y SU ENSEANZA SOBRE SOLIDARIDAD LINAJSTICA  

E-Print Network (OSTI)

aquello sopo, caualgo a halshs-00686354,version1-12Apr2012 #12;8 a sus sobrinos. Aun en los momentos en macular con sangre el pecho de Gonzalo González: "Estonces donna Llambla, quando sopo que uinie don

Paris-Sud XI, Université de

143

Materials Reliability Program: PWR Internals Material Aging Degradation Mechanism Screening and Threshold Values (MRP-175)  

Science Conference Proceedings (OSTI)

This report provides screening criteria and their technical bases for age-related degradation evaluation of Pressurized Water Reactor (PWR) internals component items. It is a key element in an overall strategy that uses knowledge of internals design, materials, and material properties and applies screening methodologies for known age-related degradation mechanisms to manage the effects of aging in PWR internals.

2005-12-12T23:59:59.000Z

144

Decentralizing urbanization : harnessing the potential of small cities in India  

E-Print Network (OSTI)

Perceived as symbols of national development or degeneration, megacities continue to dominate discourse and action related to urbanization, particularly in developing countries like India. Simultaneously, a large portion ...

Suri, Sagarika

2011-01-01T23:59:59.000Z

145

The Risk Assessment Information System  

NLE Websites -- All DOE Office Websites (Extended Search)

mesenteric lymph nodes, degeneration of bone marrow cells, and retardation of thyroid gland development. Increased mortality was observed with newborn mice after treatment...

146

simultaneous perturbation of the objective and right-hand-side vectors  

E-Print Network (OSTI)

For degenerate LO problems, the availability of strictly complementary solutions produced by IPMs ...... user i tries to allocate his total transmission power Pi.

147

com  

Science Conference Proceedings (OSTI)

... magnetic states in very high magnetic fields in a site- selective manner ... In such systems, the ground state is highly degenerate and many phases are ...

148

Quality of Security Service  

Science Conference Proceedings (OSTI)

... here has been to help determine if this reliability, predictability and efficiency can be ... That is, a range may be unitary, or degenerate, in which case it ...

2000-11-03T23:59:59.000Z

149

A predictive model for the temperature relaxation rate in dense plasmas  

DOE Green Energy (OSTI)

We present and validate a simple model for the electron-ion temperature relaxation rate in plasmas that applies over a wide range of plasma temperatures and densities, including weakly-coupled, non-degenerate as well as strongly-coupled, degenerate plasmas. Electron degeneracy and static correlation effects between electrons and ions are shown to play a cumulative role that, at low temperature, lead to relaxation rates a few times smaller than when these effects are neglected. We predict the evolution of the relaxation in dense hydrogen plasmas from the fully degenerate to the non-degenerate limit.

Daligault, Jerome [Los Alamos National Laboratory; Dimonte, Guy [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

150

ORISE: Postdoctoral Research Experiences - Matthew Garcia  

NLE Websites -- All DOE Office Websites (Extended Search)

Science and Education. Garcia obtained a doctorate in anatomy and neurobiology from the University of Kentucky in 2007 and focused his research on neuro-degeneration and...

151

Addendum: Symmetries of the energy-momentum tensor  

E-Print Network (OSTI)

In recent papers [1-3], we have discussed matter symmetries of non-static spherically symmetric spacetimes, static plane symmetric spacetimes and cylindrically symmetric static spacetimes. These have been classified for both cases when the energy-momentum tensor is non-degenerate and also when it is degenerate. Here we add up some consequences and the missing references about the Ricci tensor.

M. Sharif

2004-10-28T23:59:59.000Z

152

Introduction The retina is compartmentalized at the exter-  

E-Print Network (OSTI)

School of Medicine, Salt Lake City, UT 84132 Abstract Photoreceptor degenerations initiated in rods of novel ectopic microneuromas in the remnant inner nuclear layer (INL). Bipolar and amacrine cells engage regardless of the molecular defects that initially trigger retinal degenerations. Although remodeling may

Marc, Robert E.

153

Behavioral impulsivity and hallucinations : insights from Parkinson's disease  

E-Print Network (OSTI)

Parkinson's disease (PD) is an age-related degenerative disease of the brain, characterized by motor, cognitive, and psychiatric symptoms. Neurologists and neuroscientists now understand that several symptoms of the disease, ...

Ashourian, Paymon

2011-01-01T23:59:59.000Z

154

Fracture, aging and disease in bone  

E-Print Network (OSTI)

and R. O. Ritchie: Effect of aging on the toughness of humanof microstructure in the aging-related deterioration of thestudy of the effect of aging on human cortical bone J.

Ager, J.W.; Balooch, G.; Ritchie, R.O.

2006-01-01T23:59:59.000Z

155

Aging in Place: Smith, Media Texts and the Invisible Gendered Caregiver  

E-Print Network (OSTI)

Timonen. 2007. Home Care for Aging Populations. Northampton,and John A Krout. 2004. ?Aging in Place in Different HousingFederal Interagency Forum on Aging-Related Statistics. 2008.

Storelli, Elizangela

2010-01-01T23:59:59.000Z

156

Using nonradial pulsations to determine the envelope composition of very evolved stars  

DOE Green Energy (OSTI)

Recent observational and theoretical studies of the ZZ Ceti variables (DA degenerate dwarfs), the DBV variables (DB degenerate dwarfs), and the GW Vir variables (DO degenerate dwarfs) have shown them to be pulsating in nonradial g/sup +/-modes. The pulsation mechanism has been identified for each class of variable star and, in all cases, involves predictions of the stars envelope composition. The ZZ Ceti variables must have pure hydrogen surface layers, the DBV stars must have pure helium surface layers, and the GW Vir stars must have carbon and oxygen rich surface layers. 44 refs.

Starrfield, S.

1986-07-07T23:59:59.000Z

157

Double Hopf Bifurcation and Quasi-Periodic Flow in a Model for Baroclinic Instability  

Science Conference Proceedings (OSTI)

The interaction between pairs of dispersive waves is studied with different zonal wavenumbers in the ?-plane model for baroclinic instability. We find that degenerate (codimension 2) double Hopf bifurcations occur at isolated points in the (F2/r2,...

Irene M. Moroz; Philip Holmes

1984-11-01T23:59:59.000Z

158

Highly nonclassical photon statistics in parametric down conversion  

E-Print Network (OSTI)

We use photon counters to obtain the joint photon counting statistics from twin-beam non-degenerate parametric down conversion, and we demonstrate directly, and with no auxiliary assumptions, that these twin beams are nonclassical.

Edo Waks; Barry Sanders; Eleni Diamanti; Yoshihisa Yamamoto

2006-02-14T23:59:59.000Z

159

In-vivo cartilage contact biomechanics : an experimental and computational investigation of human ankle joint complex  

E-Print Network (OSTI)

Osteoarthritis is affecting over 20 million people in the United States, the etiology of which is still unclear. As abnormal stress is believed to be one of the factors causing the degeneration of cartilage, the combined ...

Wan, Lu, Ph. D. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

160

Pattern matching in column-strict fillings of rectangular arrays  

E-Print Network (OSTI)

increasing rows, i.e, a match of a standard tableau of shapeeach row, reading from left to right, then F is a standardrow g Figure 6.1: Possible edges in G P for a degenerate standard

Harmse, Johannes Andreas

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Snow Particle Morphology in the Seasonal Snow Cover  

Science Conference Proceedings (OSTI)

Snow precipitation degenerates rapidly once it reaches the ground. A wide variety of particle types develop in seasonal snow covers. thus leading to a wide range of snow properties. The most common varieties of particles are shown here. The ...

S. C. Colbeck

1983-06-01T23:59:59.000Z

162

A collagen based scaffold for the repair of annulus fibrosus defects  

E-Print Network (OSTI)

The intervertebral disc (IVD) is the natural cartilaginous cushion found between the osseous vertebrae of the spinal column. It is an essential element for the flexibility of the spine but undergoes major degeneration with ...

Saad, Leonide C. (Leonide Camile), 1977-

2007-01-01T23:59:59.000Z

163

An Optimal Algorithm for Purging Regular Schemes  

Science Conference Proceedings (OSTI)

A joint application of four optimizing transformations for purging imperative programselimination of useless statements, unwinding of degenerate loops, removal from loops, and removal from branch statementsis considered. A model of regular ...

D. L. Uvarov

2000-11-01T23:59:59.000Z

164

IL-17A is increased in the serum and in spinal cord CD8 and mast cells of ALS patients  

E-Print Network (OSTI)

motor neuron degeneration in ALS. Annu Rev Neurosci 2004, 3.in Familial and Sporadic ALS. Antioxid Redox Signal 2009, 4.non-native SOD1 in sporadic ALS patients. PLoS One 5-e11552.

2010-01-01T23:59:59.000Z

165

Baryons and baryonic matter in the large Nc and heavy quark limits  

E-Print Network (OSTI)

This paper explores properties of baryons and finite density baryonic matter in an artificial world in which N[subscript c], the number of colors, is large and the quarks of all species are degenerate and much larger than ...

Cohen, Thomas D.

166

Experiments with interacting Bose and Fermi gases  

E-Print Network (OSTI)

In the past few years, the study of trapped fermionic atoms evolved from the first cooling experiments which produced quantum degenerate samples to becoming one of the most exciting branches of current atomic physics ...

Stan, Claudiu Andrei

2005-01-01T23:59:59.000Z

167

Matter Collineations of Static Spacetimes with Maximal Symmetric Transverse Spaces  

E-Print Network (OSTI)

This paper is devoted to study the symmetries of the energy-momentum tensor for the static spacetimes with maximal symmetric transverse spaces. We solve matter collineation equations for the four main cases by taking one, two, three and four non-zero components of the vector $\\xi^a$. For one component non-zero, we obtain only one matter collineation for the non-degenerate case and for two components non-zero, the non-degenerate case yields maximum three matter collineations. When we take three components non-zero, we obtain three, four and five independent matter collineations for the non-degenerate and for the degenerate cases respectively. This case generalizes the degenerate case of the static spherically symmetric spacetimes. The last case (when all the four components are non-zero) provides the generalization of the non-degenerate case of the static spherically symmetric spacetimes. This gives either four, five, six, seven or ten independent matter collineations in which four are the usual Killing vectors and rest are the proper matter collineations. It is mentioned here that we obtain different constraint equations which, on solving, may provide some new exact solutions of the Einstein field equations.

M. Sharif

2007-02-10T23:59:59.000Z

168

Modeling and optimizing passive valve designs for the implantable Gold Micro-Shunt used in glaucoma treatment  

Science Conference Proceedings (OSTI)

Glaucoma is an age-related eye disease that causes ocular nerve damage, typically characterized by elevated intraocular pressure (IOP). Studies have shown that IOP can vary significantly on the order of days or even hours. Failure to control IOP spikes ... Keywords: Check-valve, Drainage device, Finite element analysis, Glaucoma, Intraocular pressure, MEMS

Judy L. Lin; Jason M. Clevenger

2009-06-01T23:59:59.000Z

169

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research  

E-Print Network (OSTI)

's personal copy Anti-epileptic drugs delay age-related loss of spiral ganglion neurons via T-type calcium of Otolaryngology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China 210008 e that anticonvulsant drugs from a family of T-type calcium channel blockers can significantly preserve spiral ganglion

Campbell, Kevin P.

170

Cell, Vol. 120, 449460, February 25, 2005, Copyright 2005 by Elsevier Inc. DOI 10.1016/j.cell.2005.02.002 ReviewThe Plasticity of Aging  

E-Print Network (OSTI)

.cell.2005.02.002 ReviewThe Plasticity of Aging: Insights from Long-Lived Mutants Cynthia Kenyon* that aging-shock transcription factor, is also completely re-pathways for aging, some of which appear to extend quired for daf-2 and Johnson, 2001; Lee et al., 2001; Lin etpathways delay age-related disease, and the molecu- al., 2001), HSF

Rosenberg, Noah

171

Effect of aging on the toughness of human cortical bone: evaluation by R-curves  

E-Print Network (OSTI)

Effect of aging on the toughness of human cortical bone: evaluation by R-curves R.K. Nallaa,b , J online 27 October 2004 Abstract Age-related deterioration of the fracture properties of bone, coupled, and hence, an understanding of how its fracture properties degrade with age is essential. The present study

Ritchie, Robert

172

SWAN: System for Wearable Audio Jeff Wilson1  

E-Print Network (OSTI)

(GIS) infrastructure for supporting geocoding and spatialization of data. Furthermore, SWAN utilizes-3]. As the population of the United States ages, there will continue to be more workers with age-related visual of the aging workforce. Wayfinding (the ability to find one's way to a destination) is dependent on the ability

173

Relay SeriesSpecific Guidance: Generic Service Life Analyses (GSLA) and Preventive Maintenance (PM) Templates  

Science Conference Proceedings (OSTI)

This report provides guidance for determining the optimum service lives for selected relay series based on the application of the relays and their service conditions. The goal is to provide guidance on replacement frequencies that will ensure that relays are replaced prior to age-related degradation causing failures, while avoiding the unnecessary burdens and issues associated with premature ...

2013-07-30T23:59:59.000Z

174

Inspection and Replacement of Baffle to Former Bolts at Point Beach-2 and Ginna Processes, Equipment Design, and Equipment Qualifica tion  

Science Conference Proceedings (OSTI)

Incidences of cracking in some earlier design European PWRs have demonstrated that the reactor vessel internals bolting may be susceptible to age-related degradation. The primary cracking mechanism is likely irradiation assisted stress corrosion cracking (IASCC). This report describes an innovative bolt inspection and replacement program developed by Westinghouse two-loop plant owners and Framatome Technologies to address the aging problem.

2000-02-24T23:59:59.000Z

175

Axion emission from a magnetized neutron gas  

SciTech Connect

By using the polarization density matrix for a neutron in a magnetic field, the axion luminosity of magnetic neutron stars that is associated with the flip of the anomalous magnetic moment of degenerate nonrelativistic neutrons is calculated. It is shown that, at values of the magnetic-field induction in the region B Greater-Than-Or-Equivalent-To 10{sup 18} G, this mechanism of axion emission is dominant in 'young' neutron stars of temperature about a few tens of MeV units. At B {approx} 10{sup 17} G, it is one of the basic mechanisms. The Fermi energy of a degenerate neutron gas in a magnetic field is found, and it is shown that there is no such mechanism of axion emission in the degenerate case.

Skobelev, V. V., E-mail: v.skobelev@inbox.ru [Moscow State Industrial University (Russian Federation)

2011-01-15T23:59:59.000Z

176

Theoretical Model and Interpretation of Dense Plasma X-Ray Thomson Scattering  

Science Conference Proceedings (OSTI)

The authors present analytical expressions for the dynamic structure factor, or form factor S(k,{omega}), which is the quantity describing the inelastic x-ray cross section from a dense plasma or a simple liquid. The results, based on the random phase approximation (RPA) for the treatment on the charged particle coupling, can be applied to describe scattering from either weakly coupled classical plasmas or degenerate electron liquids. The form factor correctly reproduces the Compton energy downshift and the usual Fermi-Dirac electron velocity distribution for S(k,{omega}) in the case of a cold degenerate plasma. the usual concept of scattering parameter is also reinterpreted for the degenerate case in order to include the effect of the Thomas-Fermi screening. The results shown in this work can be applied to interpreting x-ray scattering in warm dense plasmas occurring in inertial confinement fusion experiments or inside the interior of planets.

Gregori, G; Landen, O; Hicks, D; Pasley, J; Collins, G; Celliers, P; Bastea, M; Glenzer, S

2002-04-03T23:59:59.000Z

177

Progenitors of type Ia supernovae in elliptical galaxies  

Science Conference Proceedings (OSTI)

Although there is a nearly universal agreement that type Ia supernovae are associated with the thermonuclear disruption of a CO white dwarf, the exact nature of their progenitors is still unknown. The single degenerate scenario envisages a white dwarf accreting matter from a non-degenerate companion in a binary system. Nuclear energy of the accreted matter is released in the form of electromagnetic radiation or gives rise to numerous classical nova explosions prior to the supernova event. We show that combined X-ray output of supernova progenitors and statistics of classical novae predicted in the single degenerate scenario are inconsistent with X-ray and optical observations of nearby early type galaxies and galaxy bulges. White dwarfs accreting from a donor star in a binary system and detonating at the Chandrasekhar mass limit can account for no more than {approx}5% of type Ia supernovae observed in old stellar populations.

Gilfanov, M.; Bogdan, A.

2011-09-21T23:59:59.000Z

178

Electrostatic solitary ion waves in dense electron-positron-ion magnetoplasma  

SciTech Connect

The nonlinear coupled ion-acoustic and ion-cyclotron waves propagating obliquely to the external magnetic field in dense collisionless electron-positron-ion magnetoplasma are investigated using Sagdeev potential method. A semiclassical approach is used. Electrons and positrons are treated as degenerate Fermi gases described by Thomas-Fermi density distribution and ions behave as classical gas. It is found that the presence of degenerate positrons in a dense Thomas-Fermi plasma significantly modifies the structure of solitary waves by restricting the electrostatic potential to a certain maximum value which depends upon the concentration of positrons in the system. It is also noted that only subsonic humplike solitary waves can exist and for a given angle of propagation, the presence of degenerate positrons diminishes the amplitude as well as width of the solitary wave.

Jehan, Nusrat [Department of Physics, Theoretical Plasma Physics Group, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Pakistan Atomic Energy Commission, P.O. Box 1114, Islamabad 44000 (Pakistan); Salahuddin, M. [Pakistan Atomic Energy Commission, P.O. Box 1114, Islamabad 44000 (Pakistan); Mahmood, S. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Department of Physics, Theoretical Plasma Physics Group, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2009-04-15T23:59:59.000Z

179

Generation of polarization entangled photons using type-II doubly periodically poled lithium niobate waveguides  

E-Print Network (OSTI)

In this paper, we address the issue of the generation of non-degenerate cross-polarization entangled photon-pairs using type-II periodically poled lithium niobate. We show that, by an appropriate engineering of the quasi-phase-matching grating, it is possible to simultaneously satisfy the conditions for two spontaneous parametric down-conversion processes, namely ordinary pump photon down-conversion to either extraordinary signal and ordinary idler paired photons, or to ordinary signal and extraordinary idler paired photons. In contrast to single type-II phase-matching, these two processes, when enabled together, can lead to the direct production of cross-polarization entangled state for non degenerate signal and idler wavelengths. Such a scheme should be of great interest in applications requiring polarization entangled non degenerate paired photons with, for instance, one of the entangled photons at an appropriate wavelength being used for local operation or for quantum storage in an atomic ensemble, and th...

Thyagarajan, K; Lugani, J; Ghosh, S; Martin, A; Ostrowsky, D B; Alibart, O; Tanzilli, S

2009-01-01T23:59:59.000Z

180

Quantum Invariants of the Pairing Hamiltonian  

E-Print Network (OSTI)

Quantum invariants of the orbit dependent pairing problem are identified in the limit where the orbits become degenerate. These quantum invariants are simultaneously diagonalized with the help of the Bethe ansatz method and a symmetry in their spectra relating the eigenvalues corresponding to different number of pairs is discussed. These quantum invariants are analogous to the well known rational Gaudin magnet Hamiltonians which play the same role in the reduced pairing case (i.e., orbit independent pairing with non degenerate energy levels). It is pointed out that although the reduced pairing and the degenerate cases are opposite of each other, the Bethe ansatz diagonalization of the invariant operators in both cases are based on the same algebraic structure described by the rational Gaudin algebra.

Y. Pehlivan

2008-06-11T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Negative Off-Diagonal Conductivities in a Weakly Coupled Quark Gluon Plasma  

E-Print Network (OSTI)

We calculate the conductivity matrix of a weakly coupled quark-gluon plasma at the leading-log order. By setting all quark chemical potentials to be identical, the diagonal conductivities become degenerate and positive, while the off-diagonal ones become degenerate but negative (or zero when the chemical potential vanishes). This means a potential gradient of a certain fermion flavor can drive backward currents of other flavors. A simple explanation is provided for this seemingly counter intuitive phenomenon. It is speculated that this phenomenon is generic and most easily measured in cold atom experiments.

Jiunn-Wei Chen; Yen-Fu Liu; Shi Pu; Yu-Kun Song; Qun Wang

2013-08-13T23:59:59.000Z

182

Negative Off-Diagonal Conductivities in a Weakly Coupled Quark Gluon Plasma  

E-Print Network (OSTI)

We calculate the conductivity matrix of a weakly coupled quark-gluon plasma at the leading-log order. By setting all quark chemical potentials to be identical, the diagonal conductivities become degenerate and positive, while the off-diagonal ones become degenerate but negative (or zero when the chemical potential vanishes). This means a potential gradient of a certain fermion flavor can drive backward currents of other flavors. A simple explanation is provided for this seemingly counter intuitive phenomenon. It is speculated that this phenomenon is generic and most easily measured in cold atom experiments.

Chen, Jiunn-Wei; Pu, Shi; Song, Yu-Kun; Wang, Qun

2013-01-01T23:59:59.000Z

183

Multiloop World-Line Green Functions from String Theory  

E-Print Network (OSTI)

We show how the multiloop bosonic Green function of closed string theory reduces to the world-line Green function as defined by Schmidt and Schubert in the limit where the string world-sheet degenerates into a $\\Phi^3$ particle diagram. To obtain this correspondence we have to make an appropriate choice of the local coordinates defined on the degenerate string world sheet. We also present a set of simple rules that specify, in the explicit setting of the Schottky parametrization, which is the corner of moduli space corresponding to a given multiloop $\\Phi^3$ diagram.

Kaj Roland; Haru-Tada Sato

1996-04-24T23:59:59.000Z

184

Charged Vacuum Bubble Stability  

E-Print Network (OSTI)

A type of scenario is considered where electrically charged vacuum bubbles, formed from degenerate or nearly degenerate vacuua separated by a thin domain wall, are cosmologically produced due to the breaking of a discrete symmetry, with the bubble charge arising from fermions residing within the domain wall. Stability issues associated with wall tension, fermion gas, and Coulombic effects for such configurations are examined. The stability of a bubble depends upon parameters such as the symmetry breaking scale and the fermion coupling. A dominance of either the Fermi gas or the Coulomb contribution may be realized under certain conditions, depending upon parameter values.

J. R. Morris

1998-10-20T23:59:59.000Z

185

Energy structure of non-hydrogen-like impurities in quantum wells without spin-orbit coupling  

Science Conference Proceedings (OSTI)

Hole states localized at an acceptor in a quantum well formed of a semiconductor with cubic symmetry without spin-orbit coupling (the symmetry {Gamma}{sub 15}) are considered. It is shown that the triply degenerate level is split, and the energies of the levels are calculated as functions of the well width.

Romanov, K. S., E-mail: const@stella.ioffe.ru; Averkiev, N. S. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2012-06-15T23:59:59.000Z

186

Renewable energy cognition and attitude of junior high school students in Kaohsiung city  

Science Conference Proceedings (OSTI)

The purpose of this study is to investigate the concepts and attitudes of renewable energy resources for the junior high school students in Kaohsiung city. Energy is an integral part of our daily lives. If energy was insufficiency, our lives would degenerate ... Keywords: energy, energy education, renewable energy

Wen-Jiuh Chiang; Rong-Jyue Fang; Hung Chien Nien; Hua-Lin Tsa

2010-04-01T23:59:59.000Z

187

Iterated Peiffer pairings in the Moore complex of a simplicial group.  

E-Print Network (OSTI)

We introduce a pairing structure within the Moore complex NG of a simplicial group G and use it to investigate generators for NG_n\\cap D_n where D_n is the subgroup generated by degenerate elements. This is applied to the study of algebraic models for homotopy types.

A Mutlu; T Porter.

188

On flips of unitary buildings I: Classification of flips  

E-Print Network (OSTI)

We classify flips of buildings arising from non-degenerate unitary spaces of dimension at least 4 over finite fields of odd characteristic in terms of their action on the underlying vector space. We also construct certain geometries related to flips and prove that these geometries are flag transitive.

Blok, Rieuwert J

2010-01-01T23:59:59.000Z

189

N d'ordre 136-2009 THESE DE L'UNIVERSITE DE LYON  

E-Print Network (OSTI)

BERNARD LYON 1 et EAST CHINA NORMAL UNIVERSITY ECOLE DOCTORALE ET SCHOOL OF LIFE SCIENCE DIPLOME DE SCHOOL, L'UNIVERSITE CLAUDE BERNARD LYON 1 And SCHOOL OF LIFE SCIENCE, EAST CHINA NORMAL UNIVERSITY CO induces muscle degeneration in mammals and worms, and to find new drugs that might help in reducing muscle

Paris-Sud XI, Université de

190

MIT Plasma Fusion Sciences Center IAP Seminar! Jan 10th, 2012!  

E-Print Network (OSTI)

MIT Plasma Fusion Sciences Center IAP Seminar! Jan 10th, 2012! ! ! ! ! ! Otto Landen! Associate-07NA27344 Inertial Confinement Fusion Physics and Challenges*! #12;The NIF ignition experiments-degenerate fuel Spherical collapse of the shell produces a central hot spot surrounded by cold, dense main fuel

191

Singlet Free Energies of a Static Quark-Antiquark Pair  

E-Print Network (OSTI)

We study the singlet part of the free energy of a static quark anti-quark pair at finite temperature in three flavor QCD with degenerate quark masses using $N_{\\tau}=4$ and 6 lattices with Asqtad staggered fermion action. We look at thermodynamics of the system around phase transition and study its scaling with lattice spacing and quark masses.

Konstantin Petrov

2004-09-01T23:59:59.000Z

192

Circumnavigating an ocean of incompressible light  

E-Print Network (OSTI)

This is a popular science article to appear on the "Il Nuovo Saggiatore" magazine of the Italian Physical Society. It aims at introducing a broad audience of physicists to the most recent trends in many-body physics of degenerate quantum gases with a special attention to quantum fluids of light and the quest towards quantum Hall liquids of light.

Iacopo Carusotto

2012-12-26T23:59:59.000Z

193

Coupled left-shift of Nav channels: modeling the Na+-loading and dysfunctional excitability of damaged axons  

Science Conference Proceedings (OSTI)

Injury to neural tissue renders voltage-gated Na+ (Nav) channels leaky. Even mild axonal trauma initiates Na+ -loading, leading to secondary Ca2+-loading and white matter degeneration. The nodal isoform is Nav1.6 ... Keywords: Arrhythmia, Diffuse axonal injury, Extracellular space, Hodgkin-Huxley, Myelinated, Na/K-ATPase, Neuropathic pain

Pierre-Alexandre Boucher; Bla Jos; Catherine E. Morris

2012-10-01T23:59:59.000Z

194

Coulomb corrections and thermo-conductivity of a dense plasma  

E-Print Network (OSTI)

We point out a confusion arising sometimes in using chemical potential in plasma with coulomb interactions. The results of our consideration are applied to discussion of nuclear reactions screening. Finally, we present a transparent derivation of thermal conductivity coefficient of degenerate electron gas.

Glazyrin, S I

2009-01-01T23:59:59.000Z

195

ON THE COMPETITION BETWEEN FERROMAGNETIC AND ANTIFERROMAGNETIC STATES IN Sr2MnMoO6  

E-Print Network (OSTI)

It is argued that the magnetic behavior of Sr2MnMoO6 is determined by the existence of two total energy minima corresponding to the metallic ferromagnetic and insulating antiferromagnetic states, which may be nearly degenerate depending on the magnitude of the breathing distortion. PACS: 71.20.Be; 71.70.Gm; 72.25.Ba; 75.30.Et

I. V. Solovyev

2002-01-01T23:59:59.000Z

196

General Hormander and Mikhlin conditions for multipliers of Besov spaces  

E-Print Network (OSTI)

Here a new condition for the geometry of Banach spaces is introduced and the operator--valued Fourier multiplier theorems in weighted Besov spaces are obtained. Particularly, connections between the geometry of Banach spaces and Hormander-Mikhlin conditions are established. As an application of main results the regularity properties of degenerate elliptic differential operator equations are investigated.

Shahmurov, Rishad

2008-01-01T23:59:59.000Z

197

Finsleroid-regular space. Landsberg-to-Berwald implication  

E-Print Network (OSTI)

By performing required evaluations, we show that in the Finsleroid-regular space the Landsberg-space condition just degenerates to the Berwald-space condition (at any dimension number $N\\ge2$). Simple and clear expository representations are obtained. Due comparisons with the Finsleroid-Finsler space are indicated. Keywords: Finsler metrics, spray coefficients, curvature tensors.

Asanov, G S

2008-01-01T23:59:59.000Z

198

The Free Energy of Electron Gas  

Science Conference Proceedings (OSTI)

The energy and free energy of a semi?degenerate gas obeying the Fermi statistics are computed as functions of temperature and concentration. The significance of the deviation of the free energy from the limiting high temperature value is illustrated by calculating the degree of thermal ionization of potassium vapor under conditions of high electron concentration.

A. R. Gordon

1936-01-01T23:59:59.000Z

199

A Low-Power Wide-Linear-Range Transconductance Amplifier  

Science Conference Proceedings (OSTI)

The linear range of approximately 75 mV of traditional subthreshold transconductance amplifiers is too small for certain applicationsfor example, for filters in electronic cochleas, where it is desirable to handle loud sounds without ... Keywords: amplifier, cochlea, degeneration, dynamic range, low-power, noise, transconductance, wide-linear-range

Rahul Sarpeshkar; Richard F. Lyon; Carver Mead

1997-05-01T23:59:59.000Z

200

Measuring Smuon-Selectron Mass Splitting at the LHC and Patterns of Supersymmetry Breaking  

E-Print Network (OSTI)

01 . The enhancement diverges as the slepton mass approaches ei- ther neutralino mass. The benefits of the enhancement may be diluted for highly degenerate spectra by the fact that leptons coming from such chains will tend to be softer and thus harder...

Allanach, B C; Conlon, Jo; Lester, Christopher G

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Distinguishing spins in supersymmetric and universal extra dimension models at the large hadron collider.  

E-Print Network (OSTI)

to verify the UED spin assignments if the spectrum is quasi-degenerate like that in table 1. The SUSY mass spectrum, on the other hand, does ?01 ? 0 2 uL eR eL 96 177 537 143 202 Table 2: SUSY masses in GeV, for SPS point 1a. not naturally have the same...

Smillie, Jennifer M; Webber, Bryan R

202

Computational modeling of a prosthetic shoulder: our experience with the anybody modeling system  

Science Conference Proceedings (OSTI)

When wear or tear of the rotator cuff becomes non-treatable, the glenohumeral joint degeneration can lead to upper limb pseudoparalysis, hence requiring a shoulder arthroplasty. Data indicating the performance of today's prostheses remain unsatisfactory ... Keywords: deltoid, modeling, rotator cuff tear, shoulder

Yoann Collet; Patrice Ttreault; John Rasmussen; Natalia Nuo; Nicola Hagemeister

2007-05-01T23:59:59.000Z

203

Computational modeling of a prosthetic shoulder: our experience with the anybody modeling system  

Science Conference Proceedings (OSTI)

When wear or tear of the rotator cuff becomes nontreatable, the glenohumeral joint degeneration can lead to upper limb pseudoparalysis, hence requiring a shoulder arthroplasty. Data indicating the performance of today's prostheses remain unsatisfactory ... Keywords: deltoid, modeling, rotator cuff tear, shoulder

Yoann Collet; Patrice Ttreault; John Rasmussen; Natalia Nuo; Nicola Hagemeister

2007-05-01T23:59:59.000Z

204

Transversal plasma resonance in a nonmagnetized plasma and possibilities of practical employment of it  

E-Print Network (OSTI)

It is shown that in a nonmagnetized plasma, beside the longitudinal Langmuir resonance, there may also exist the transversal resonance. Both these resonance kinds are degenerated. Employment of the transversal resonance makes it possible to design resonators and filters, as well as powerful single-frequency lasers operating on the basis of collective oscillations of plasma.

F. F. Mende

2005-06-09T23:59:59.000Z

205

Higgs boson resonance parameters and the finite temperature phase transition in a chirally invariant Higgs-Yukawa model  

E-Print Network (OSTI)

We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks.

John Bulava; Philip Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy

2011-11-11T23:59:59.000Z

206

REGULARITY FOR A DOUBLY NONLINEAR PARABOLIC EQUATION  

E-Print Network (OSTI)

REGULARITY FOR A DOUBLY NONLINEAR PARABOLIC EQUATION JUHA KINNUNEN Abstract. This survey focuses on regularity results for certain degenerate doubly nonlinear parabolic equations in the case when the Lebesgue This note focuses on the regularity of nonnegative weak solutions to the doubly nonlinear parabolic equation

Kinnunen, Juha

207

Neurobiology of Disease Loss of ALS2 Function Is Insufficient to Trigger Motor  

E-Print Network (OSTI)

Neurobiology of Disease Loss of ALS2 Function Is Insufficient to Trigger Motor Neuron Degeneration, Baltimore, Maryland 21205 Amyotrophic lateral sclerosis (ALS), the most common motor neuron disease, is caused by a selective loss of motor neurons in the CNS. MutationsintheALS2

Blackshaw, Seth

208

Color superconductivity and the strange quark  

E-Print Network (OSTI)

At ultra-high density, matter is expected to form a degenerate Fermi gas of quarks in which there is a condensate of Cooper pairs of quarks near the Fermi surface: color superconductivity. In these proceedings I review some of the underlying physics, and discuss outstanding questions about the phase structure of ultra-dense quark matter.

Mark G Alford

2005-12-01T23:59:59.000Z

209

JOURNAL DE PHYSIQUE CoUoque C 1, supplhneat au no 2-3, Tome 32, Nvrier-Mars 1971,page C 1 -1179 TEMPERATURE DEPENDENCE OF SPIN WAVE ENERGIES IN ERBIUM  

E-Print Network (OSTI)

. STRINGFELLOW (*) Atomic Energy of Canada Limited, Chalk River, Ontario, Canada R6sum6. -Les modes de,). At cQ/2n = (0, 0, 1) and (0, 0, 2) these modes are degenerate. The measurements were made on a crystal of Er with a triple axis crystal spectrometer controlled in the constant momentum transfer (constant - Q

Paris-Sud XI, Université de

210

Black Strings, Black Rings and State-space Manifold  

E-Print Network (OSTI)

State-space geometry is considered, for diverse three and four parameter non-spherical horizon rotating black brane configurations, in string theory and $M$-theory. We have explicitly examined the case of unit Kaluza-Klein momentum $D_1D_5P$ black strings, circular strings, small black rings and black supertubes. An investigation of the state-space pair correlation functions shows that there exist two classes of brane statistical configurations, {\\it viz.}, the first category divulges a degenerate intrinsic equilibrium basis, while the second yields a non-degenerate, curved, intrinsic Riemannian geometry. Specifically, the solutions with finitely many branes expose that the two charged rotating $D_1D_5$ black strings and three charged rotating small black rings consort real degenerate state-space manifolds. Interestingly, arbitrary valued $M_5$-dipole charged rotating circular strings and Maldacena Strominger Witten black rings exhibit non-degenerate, positively curved, comprehensively regular state-space configurations. Furthermore, the state-space geometry of single bubbled rings admits a well-defined, positive definite, everywhere regular and curved intrinsic Riemannian manifold; except for the two finite values of conserved electric charge. We also discuss the implication and potential significance of this work for the physics of black holes in string theory.

Stefano Bellucci; Bhupendra Nath Tiwari

2010-10-19T23:59:59.000Z

211

Atomic Physics 80301 Problem Set 2 Fall 2005 Your Answers to these problems will be collected in class on Sept. 7.  

E-Print Network (OSTI)

in class on Sept. 7. 1. The ground state of hydrogen is a 1s state (orbital angular momentum eigenvalue l substates m = ±1/2. The angular wave functions of the two degenerate states are |j, m = Y00(, ) m 1 4 m and write out the angular wave functions for each of the 6 possible substates. 2. The hyperfine structure

Johnson, Walter R.

212

Z .Optics Communications 6112 1999 xxx www.elsevier.comrlocateroptcom  

E-Print Network (OSTI)

of internal atomic ground states with relative amplitudes and phases such that the excitation amplitudes of different ground states to the same excited state destructively interfere. Thus when an atom in such a state exist if the constituent substates are degenerate in energy and thus do not change their relative phase

Summy, Gil

213

China's Environmental Issues, a Domestic Challenge with Regional and International Implications  

Science Conference Proceedings (OSTI)

China and its population are confronted with fundamental environmental challenges, as both, environmental degeneration and the impact of climate change exhibit critical social, economic and political implications for their future development. Among the ... Keywords: Chinese Politics, Climate Change, Environment, Global, International Relations, Regional

Christian Ploberger

2013-07-01T23:59:59.000Z

214

The Iterative Unitary Matrix Multiply Method and Its Application to Quantum Kicked Rotator  

E-Print Network (OSTI)

We use the iterative unitary matrix multiply method to calculate the long time behavior of the resonant quantum kicked rotator with a large denominator. The delocalization time is exponentially large. The quantum wave delocalizes through degenerate states. At last we construct a nonresonant quantum kicked rotator with delocalization.

Tao Ma

2007-09-14T23:59:59.000Z

215

Genetic and biochemical analysis of solvent formation in Clostridium acetobutylicum  

DOE Green Energy (OSTI)

The anaerobic organism Clostridium acetobutylicum has been used for commercial production of important organic solvents due to its ability to convert a wide variety of crude substrates to acids and alcohols. Current knowledge concerning the molecular genetics, cell regulation and metabolic engineering of this organism is still rather limited. The objectives are to improve the knowledge of the molecular genetics and enzymology of Clostridia in order to make genetic alterations which will more effectively channel cell metabolism toward production of desired products. Two factors that limit butanol production in continuous cultures are: (1) The degeneration of the culture, with an increase in the proportion of cells which are incapable of solvent production. Currently isolated degenerate strains are being evaluated to analyze the molecular mechanism of degeneration to determine if it is due to a genetic loss of solvent related genes, loss of a regulatory element, or an increase in general mutagenesis. Recent studies show two general types of degenerates, one which seems to have lost essential solvent pathway genes and another which has not completely lost all solvent production capability and retains the DNA bearing solvent pathway genes. (2) The production of hydrogen which uses up reducing equivalents in the cell. If the reducing power were more fully directed to the reduction reactions involved in butanol production, the process would be more efficient. The authors have studied oxidation reduction systems related to this process. These studies focus on ferredoxin and rubredoxin and their oxidoreductases.

Bennett, G.N.; Rudolph, F.B.

1998-05-01T23:59:59.000Z

216

10 X-rays from Cataclysmic Variables  

E-Print Network (OSTI)

Cataclysmic Variables ? (CVs) are a distinct class of interacting binaries, transferring mass from a donor star to a degenerate accretor, a white dwarf (WD). In all observational determinations, and as is required by theory for stable mass transfer, the donor star is of lower mass than the accretor.

Erik Kuulkers; Andrew Norton; Axel Schwope; Brian Warner

2003-01-01T23:59:59.000Z

217

The quadratic-form identity for constructing the Hamiltonian structures of the discrete integrable systems  

Science Conference Proceedings (OSTI)

The quadratic-form identity is extended to the discrete version which can be used to construct the Hamiltonian structures of the discrete integrable systems associated with the Lie algebra possessing degenerate Killing forms. Especially, it can be used ... Keywords: Discrete quadratic-form identity, Hamiltonian structure, Integrable couplings, Liouville integrability, Toda hierarchy

Yuqin Yao; Jie Ji; Dengyuan Chen; Yunbo Zeng

2008-12-01T23:59:59.000Z

218

AUTOMATIC RETINA EXUDATES SEGMENTATION WITHOUT A MANUALLY LABELLED TRAINING SET  

Science Conference Proceedings (OSTI)

Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy which can be assessed by detecting exudates (a type of bright lesion) in fundus images. In this work, two new methods for the detection of exudates are presented which do not use a supervised learning step and therefore do not require ground-truthed lesion training sets which are time consuming to create, difficult to obtain, and prone to human error. We introduce a new dataset of fundus images from various ethnic groups and levels of DME which we have made publicly available. We evaluate our algorithm with this dataset and compare our results with two recent exudate segmentation algorithms. In all of our tests, our algorithms perform better or comparable with an order of magnitude reduction in computational time.

Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2011-01-01T23:59:59.000Z

219

Steam Generator Management Program: Investigation of Steam Generator Secondary-Side Degradation  

Science Conference Proceedings (OSTI)

This document reviews and discusses age-related degradation that has occurred in the carbon steel internal components in the steam drums of Westinghouse steam generators (SGs), especially in original and early replacement SGs. The degradation is characterized by gradual thinning (loss of material) that is generally localized in the components as a result of exposure to high-velocity steam-water mixtures. Material loss from internal components has been noted during secondary-side visual inspections of ori...

2011-09-20T23:59:59.000Z

220

Low-Voltage Environmentally-Qualified Cable License Renewal Industry Report -- Revision 1  

Science Conference Proceedings (OSTI)

Low-voltage environmentally-qualified cable components have been evaluated relative to the effects of age-related degradation mechanisms; the capability of current design limits, inservice examination, testing, repair, refurbishment, and other programs to manage these effects; and the assurance that these cable components can continue to perform their intended safety functions in the license renewal term. This industry report (IR), one of a series of ten, provides a generic technical basis for evaluation...

1994-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Materials Reliability Program: Technical Basis for ASME Section XI Code Case on Flaw Tolerance of Cast Austenitic Stainless Steel (CASS) Piping (MRP-362)  

Science Conference Proceedings (OSTI)

Thermal aging of cast austenitic stainless steel (CASS) piping is a concern for long-term operation of nuclear power plants. The effects of aging in susceptible (i.e., high delta ferrite) CASS piping and components must be managed through the license renewal period. In the United States, utilities must follow the guidance for managing age-related degradation identified in the Generic Aging Lessons Learned (GALL) report, which may include analyses or inspections to demonstrate that the piping systems ...

2013-10-09T23:59:59.000Z

222

Nondestructive ultrasonic testing of materials  

DOE Patents (OSTI)

Reflection wave forms obtained from aged and unaged material samples can be compared in order to indicate trends toward age-related flaws. Statistical comparison of a large number of data points from such wave forms can indicate changes in the microstructure of the material due to aging. The process is useful for predicting when flaws may occur in structural elements of high risk structures such as nuclear power plants, airplanes, and bridges.

Hildebrand, Bernard P. (Richland, WA)

1994-01-01T23:59:59.000Z

223

Nondestructive ultrasonic testing of materials  

DOE Patents (OSTI)

Reflection wave forms obtained from aged and unaged material samples can be compared in order to indicate trends toward age-related flaws. Statistical comparison of a large number of data points from such wave forms can indicate changes in the microstructure of the material due to aging. The process is useful for predicting when flaws may occur in structural elements of high risk structures such as nuclear power plants, airplanes, and bridges. 4 figs.

Hildebrand, B.P.

1994-08-02T23:59:59.000Z

224

LWR Sustainability: Assessment of Aging of Nuclear Power Plant Safety Related Concrete Strutures  

Science Conference Proceedings (OSTI)

Current regulatory testing and inspection requirements are reviewed and a summary of degradation experience is presented. Techniques commonly used to inspect NPP concrete structures to assess and quantify age-related degradation are summarized. An approach for conduct of condition assessments of structures in NPPs is presented. Criteria, based primarily on visual indications, are provided for use in classification and assessment of concrete degradation. Materials and techniques for repair of degraded structures are generally discussed.

Graves III, Herman [U.S. Nuclear Regulatory Commission; Naus, Dan J [ORNL

2013-01-01T23:59:59.000Z

225

Time-Limited Aging Analysis Report for the Edwin I. Hatch Nuclear Power Plant  

Science Conference Proceedings (OSTI)

The option to operate a nuclear power plant beyond its initial license term of 40 years is an important factor in financial decisions and long-term planning for utility asset management and capital improvement. Southern Company has submitted an application for the renewal of its operating licenses for the E. I. Hatch Nuclear Power Plant. As part of the application preparation process, Southern Company has reviewed its design and licensing basis for Plant Hatch for time-limited, aging-related assumptions....

2000-04-11T23:59:59.000Z

226

Aging Management Guidelines for Commercial Nuclear Power Plants -- Electrical and Mechanical Penetrations  

Science Conference Proceedings (OSTI)

As part of the application process for license renewal, nuclear utilities must perform an evaluation to confirm that they have appropriately considered aging effects on plant components within the scope of the License Renewal Rule. This report provides guidelines for managing relevant degradation mechanisms applicable to electrical and mechanical penetrations in nuclear power plants. Use of these guidelines will provide utilities with a basis for verifying that effective methods for managing age-related ...

2002-04-25T23:59:59.000Z

227

Life testing of a low voltage air circuit breaker  

Science Conference Proceedings (OSTI)

A DS-416 low voltage air circuit breaker manufactured by Westinghouse was mechanically cycled to identify age-related degradation in the various breaker subcomponents, specifically the power-operated mechanism. This accelerated aging test was performed on one breaker unit for over 36,000 cycles. Three separate pole shafts, one with a 60-degree weld, one with a 120-degree weld, and one with a 180-degree weld in the third pole lever were used to characterize cracking in the welds. In addition, during the testing three different operating mechanisms and several other parts were replaced as they became inoperable. Among the seven welds on the pole shaft, {number_sign}1 and {number_sign}3 were found to be critical ones whose fracture can result in misalignment of the pole levers. This can lead to problems with the operating mechanism, including the burning of coils, excessive wear in certain parts, and overstressed linkages. Furthermore, the limiting service life of a number of subcomponents of the power-operated mechanism, including the operating mechanism itself, were assessed. Based on these findings, suggestions are provided to alleviate the age-related degradation that could occur as a result of normal closing and opening of the breaker contacts during its service life. Also, cause and effect analyses of various age-related degradation in various breaker parts are discussed.

Subudhi, M. [Brookhaven National Lab., Upton, NY (United States); Aggarwal, S. [Nuclear Regulatory Commission, Washington, DC (United States)

1992-06-01T23:59:59.000Z

228

Life testing of a low voltage air circuit breaker  

Science Conference Proceedings (OSTI)

A DS-416 low voltage air circuit breaker manufactured by Westinghouse was mechanically cycled to identify age-related degradation in the various breaker subcomponents, specifically the power-operated mechanism. This accelerated aging test was performed on one breaker unit for over 36,000 cycles. Three separate pole shafts, one with a 60-degree weld, one with a 120-degree weld, and one with a 180-degree weld in the third pole lever were used to characterize cracking in the welds. In addition, during the testing three different operating mechanisms and several other parts were replaced as they became inoperable. Among the seven welds on the pole shaft, {number sign}1 and {number sign}3 were found to be critical ones whose fracture can result in misalignment of the pole levers. This can lead to problems with the operating mechanism, including the burning of coils, excessive wear in certain parts, and overstressed linkages. Furthermore, the limiting service life of a number of subcomponents of the power-operated mechanism, including the operating mechanism itself, were assessed. Based on these findings, suggestions are provided to alleviate the age-related degradation that could occur as a result of normal closing and opening of the breaker contacts during its service life. Also, cause and effect analyses of various age-related degradation in various breaker parts are discussed.

Subudhi, M. (Brookhaven National Lab., Upton, NY (United States)); Aggarwal, S. (Nuclear Regulatory Commission, Washington, DC (United States))

1992-01-01T23:59:59.000Z

229

Establishing a rodent (Fischer 344 rat) model of mild cognitive impairment in aging  

E-Print Network (OSTI)

Mild Cognitive Impairment is characterized by age-related decline in a variety of cognitive domains, including reference and working memory and olfactory function. Importantly, declining age-related mnemonic abilities is not inevitable; learning and memory deficits emerge in some people by middle-age while others remain largely cognitively-intact even at advanced chronological ages. The goal of this thesis is to establish a Fischer 344 (F344) rat model with some features of human cognitive aging which can then be utilized to undercover the neurobiological underpinnings of age-related cognitive deficits. Young (6 mo), middle-aged (11 mo), and aged (22 mo) F344 rats were behaviorally characterized in a well-established reference memory version of the Morris water maze task. Indeed, age-related impairments did occur across the lifespan. Moreover, the reference memory protocol used here was sufficiently sensitive to detect a difference in individual abilities among aged F344 rats such that approximately half of the rats performed on par with young while the other half performed outside this range, demonstrating impairment. These data mimic individual differences in declarative memory among aged humans. Subsequently, subsets of rats initially characterized on the reference memory version of the water maze were tested on either a spatial working memory water maze task or an olfactory discrimination task. Despite detecting an age-related delay-dependent decline in spatial working memory, this impairment was not correlated with spatial reference memory. In contrast, a strong and significant relationship was observed among aged rats in the odor discrimination task such that aged rats with the worst spatial reference memory were also the most impaired in their ability to discriminate odors for a food reward. Importantly, this subset of cognitively-impaired rats was not impaired on digging media discrimination problems with identical task demands, nor were they anosmic. These data are among the first to demonstrate a cross-domain cognitive deficit in a rodent model of human aging. Together, the current study both confirms the use of the naturalistic F344 rat model for the study of cognitive deficits within the context of aging and provides the most comprehensive cognitive profile of this rat population to date.

LaSarge, Candi Lynn

2007-05-01T23:59:59.000Z

230

Analytic Perturbation Theory and Renormalization Analysis of Matter Coupled to Quantized Radiation  

E-Print Network (OSTI)

For a large class of quantum mechanical models of matter and radiation we develop an analytic perturbation theory for non-degenerate ground states. This theory is applicable, for example, to models of matter with static nuclei and non-relativistic electrons that are coupled to the UV-cutoff quantized radiation field in the dipole approximation. If the lowest point of the energy spectrum is a non-degenerate eigenvalue of the Hamiltonian, we show that this eigenvalue is an analytic function of the nuclear coordinates and of $\\alpha^{3/2}$, $\\alpha$ being the fine structure constant. A suitably chosen ground state vector depends analytically on $\\alpha^{3/2}$ and it is twice continuously differentiable with respect to the nuclear coordinates.

Marcel Griesemer; David Hasler

2008-01-29T23:59:59.000Z

231

Ultrastructural changes in rat hepatocytes following acute methyl mercury intoxication  

SciTech Connect

Male rats were given daily subcutaneous injections of methylmercuric chloride (CH/sub 3/HgCl) at a dosage of 10 mg/kg body weight for 4 days. The earliest ultrastructural changes consisted of dilatation of the rough endoplasmic reticulum, wavy transformation of the mitochondrial membranes and occasional accumulation of liposomes. Focal areas of cytoplasmic degradation were observed 1 day after the initial administration of mercury. An increased number of lysosomes as well as swelling and floccular degeneration of the mitochondria were frequently observed at 2 days. Sequestration of cytoplasmic organelles within the hepatocytes, extrusion of degenerated hepatic organelles and cytoplasmic debris into the sinusoid could be observed 24 hours after the initial mercury administration and became a frequent finding after 4 days of intoxication. (auth)

Desnoyers, P.A.; Chang, L.W.

1975-06-01T23:59:59.000Z

232

Plasma dispersion function for a Fermi-Dirac distribution  

SciTech Connect

A plasma dispersion function (PDF) is defined for a nonrelativistic Fermi-Dirac distribution and its properties are explored. The degree of degeneracy is described by a parameter {xi}=e{sup {mu}}{sub e}{sup /T}{sub e}, for electrons, with {mu}{sub e}/T{sub e} large and negative in the nondegenerate limit, and large and positive in the completely degenerate limit. The PDF is denoted Z(y,{xi}), where the variable y={omega}/{radical}(2)kV{sub e}, is the argument of the conventional PDF, Z(y)=Z(y,0), for a Maxwellian distribution. In the completely degenerate limit, Z(y,{xi}) approaches a logarithmic function that depends on the Fermi temperature and is independent of T{sub e}. Analytic approximations to Z(y,{xi}) are derived in terms of polylogarithmic functions for y{sup 2}>>1 and for y{sup 2}<<1.

Melrose, D. B. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Mushtaq, A. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Theoretical Plasma Physics Division, PINSTECH, Nilore, 44000 Islamabad (Pakistan)

2010-12-15T23:59:59.000Z

233

Effect of chronic high-dose exogenous cortisol on hippocampal neuronal number in aged nonhuman primates  

E-Print Network (OSTI)

Chronic exposure to increased glucocorticoid concentrations appears to lower the threshold for hippocampal neuronal degeneration in the old rat. It has been proposed that increased brain exposure to glucocorticoids may lower the threshold for hippocampal neuronal degeneration in human aging and Alzheimers disease. Here, we asked whether chronic administration of high-dose cortisol to older nonhuman primates decreases hippocampal neuronal number as assessed by unbiased stereological counting methodology. Sixteen Macaca nemestrina (pigtailed macaques) from 18 to 29 years of age were age-, sex-, and weight-matched into pairs and randomized to receive either high-dose oral hydrocortisone (cortisol) acetate (46 mg/kg/d) or placebo in twice daily palatable treats for 12 months. Hypothalamicpituitaryadrenal activity was monitored by measuring plasma adrenocorticotropin and cortisol,

James B. Leverenz; Charles W. Wilkinson; Molly Wamble; Shannon Corbin; Jo Ellen Grabber; Murray A. Raskind; Elaine R. Peskind

1999-01-01T23:59:59.000Z

234

Degeneracy Breaking of Hydrogen Atom  

E-Print Network (OSTI)

The three dimensional rotation group, SO(3), is a symmetry group of the normal hydrogen atom. Each reducible representation of this group can be associated with a degenerate energy level. If this atom is placed in an external magnetic field, the interaction between the orbital magnetic moment with this field will lead to a symmetry breaking where the symmetry group of the atom is a new group distinct from the SO(3) group. This phenomenon describes the normal Zeeman effect, where a degenerate energy level splits into several new energy levels. It is explicitly shown that each of the new energy levels can be associated with an irreducible representation of the new symmetry group.

Agung Trisetyarso; Pantur Silaban

2008-12-22T23:59:59.000Z

235

Effect of electron flow on the ordinary-extraordinary mode conversion  

SciTech Connect

Ordinary-extraordinary mode conversion in the electron cyclotron frequency range is revisited in the presence of a flowing electron component. The analytical expressions of optimal parallel refraction index and conversion efficiency are obtained from a one-dimensional cold plasma model. The presence of flowing electrons leads to an outward shift of the conversion layer and therefore increases the optimal value of parallel refraction index. If this effect is not considered, the efficiency of mode conversion degenerates. In typical tokamak plasmas, this degeneration is about a few percentages, which may induce the reflection of several tens of kilowatts of power from the cutoff layer when injecting megawatts of ECRF power into fusion plasma.

Jia Guozhang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Gao Zhe [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China) and Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

2011-10-15T23:59:59.000Z

236

On-chip quantum interference between two silicon waveguide sources  

E-Print Network (OSTI)

Integrated quantum optics promises to enhance the scale and functionality of quantum technologies, and has become a leading platform for the development of complex and stable quantum photonic circuits. Here, we report the on-chip generation and manipulation of two-photon entanglement, and high-visibility quantum interference with two photon-pair sources integrated within a reconfigurable silicon-on-insulator photonic circuit. Degenerate and non-degenerate entangled photon pairs were created and manipulated on-chip to exhibit quantum interference with visibility as high as 100.0 +/- 0.4%. Our device presents integration of photon-pair sources with dynamic quantum photonic circuitry, and the first high-visibility quantum interference between on-chip sources. These results represent a path to the next generation of monolithic quantum photonic circuits with integrated sources.

Joshua Silverstone; Damien Bonneau; Kazuya Ohira; Nob Suzuki; Haruhiko Yoshida; Norio Iizuka; Mizunori Ezaki; Robert Hadfield; Graham D. Marshall; Val Zwiller; John Rarity; Jeremy OBrien; Mark Thompson

2013-04-04T23:59:59.000Z

237

The Light Higgsino-Gaugino Window  

E-Print Network (OSTI)

Supersymmetric models are typically taken to have $\\mu$ parameter and all soft supersymmetry breaking parameters at or near the weak scale. We point out that a small window of allowed values exists in which $\\mu$ and the electroweak gaugino masses are in the few GeV range. Such models naturally solve the supersymmetry $CP$ problem, can reduce the discrepancy in $R_b$, and suppress proton decay. In this window two neutralinos are in the few GeV range, two are roughly degenerate with the $Z^0$, and both charginos are roughly degenerate with the $W^{\\pm}$ bosons. Such a signature cannot escape detection at LEP II. Models that fall in this window automatically arise from renormalizable hidden sectors in which hidden sector singlets participate only radiatively in supersymmetry breaking.

Jonathan L. Feng; Nir Polonsky; Scott Thomas

1995-11-15T23:59:59.000Z

238

Quark-mass dependence of the three-flavor QCD phase diagram at zero and imaginary chemical potential: Model prediction  

Science Conference Proceedings (OSTI)

We draw the three-flavor phase diagram as a function of light- and strange-quark masses for both zero and imaginary quark-number chemical potential, using the Polyakov-loop extended Nambu-Jona-Lasinio model with an effective four-quark vertex depending on the Polyakov loop. The model prediction is qualitatively consistent with 2+1 flavor lattice QCD prediction at zero chemical potential and with degenerate three-flavor lattice QCD prediction at imaginary chemical potential.

Sasaki, Takahiro; Sakai, Yuji; Yahiro, Masanobu [Department of Physics, Graduate School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kouno, Hiroaki [Department of Physics, Saga University, Saga 840-8502 (Japan)

2011-11-01T23:59:59.000Z

239

Production of a Fermi gas of atoms in an optical lattice  

Science Conference Proceedings (OSTI)

We prepare a degenerate Fermi gas of potassium atoms by sympathetic cooling with rubidium atoms in a one-dimensional optical lattice. In a tight lattice, we observe a change of the density of states of the system, which is a signature of quasi two-dimensional confinement. We also find that the dipolar oscillations of the Fermi gas along the tight lattice are almost completely suppressed.

Modugno, G.; Ferlaino, F.; Heidemann, R.; Roati, G.; Inguscio, M. [LENS and Dipartimento di Fisica, Universita di Firenze, and INFM, Via Nello Carrara 1, 50019 Sesto Fiorentino, (Italy)

2003-07-01T23:59:59.000Z

240

Equation of state for Entanglement in a Fermi gas  

E-Print Network (OSTI)

Entanglement distance is the maximal separation between two entangled electrons in a degenerate electron gas. Beyond that distance, all entanglement disappears. We relate entanglement distance to degeneracy pressure both for extreme relativistic and non-relativistic systems, and estimate the entanglement distance in a white dwarf. Treating entanglement as a thermodynamical quantity, we relate the entropy of formation and concurrence to relative electron distance, pressure, and temperature, to form a new equation of state for entanglement.

Christian Lunkes; Caslav Brukner; Vlatko Vedral

2004-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

The C-metric as a colliding plane wave space-time  

E-Print Network (OSTI)

It is explicitly shown that part of the C-metric space-time inside the black hole horizon may be interpreted as the interaction region of two colliding plane waves with aligned linear polarization, provided the rotational coordinate is replaced by a linear one. This is a one-parameter generalization of the degenerate Ferrari-Ibanez solution in which the focussing singularity is a Cauchy horizon rather than a curvature singularity.

J. B. Griffiths; R. G. Halburd

2007-01-10T23:59:59.000Z

242

New Kinetic Equations and Bogolyubov Energy Spectrum in a Fermi Quantum Plasma  

SciTech Connect

New type of quantum kinetic equations of the Fermi particles are derived. The Bogolyubov's type of dispersion relation, which is valid for the Bose fluid, is disclosed. Model of neutral Bose atoms in dense strongly coupled plasmas with attractive interaction is discussed. A set of fluid equations describing the quantum plasmas is obtained. Furthermore, the equation of the internal energy of degenerate Fermi plasma particles is derived.

Tsintsadze, Nodar L. [Department of Plasma Physics, E. Andronikashvili Institute of Physics, Tbilisi (Georgia); Tsintsadze, Levan N. [Graduate School of Science, Hiroshima University, Higashi-Hiroshima (Japan)

2009-10-08T23:59:59.000Z

243

Transverse electric conductivity of quantum collisional plasmas  

E-Print Network (OSTI)

Formulas for calculation of transverse dielectric function and transverse electric conductivity in quantum collisional plasmas under arbitrary degree of degeneracy of the electron gas are received. The Wigner - Vlasov - Boltzmann kinetic equation with collision integral in BGK (Bhatnagar, Gross and Krook) form in coordinate space is used. Various special cases are investigated. The case of fully degenerate quantum plasma was considered separately. Comparison with Lindhard's formula has been realized.

Latyshev, A V

2010-01-01T23:59:59.000Z

244

Transverse electric conductivity of quantum collisional plasmas  

E-Print Network (OSTI)

Formulas for calculation of transverse dielectric function and transverse electric conductivity in quantum collisional plasmas under arbitrary degree of degeneracy of the electron gas are received. The Wigner - Vlasov - Boltzmann kinetic equation with collision integral in BGK (Bhatnagar, Gross and Krook) form in coordinate space is used. Various special cases are investigated. The case of fully degenerate quantum plasma was considered separately. Comparison with Lindhard's formula has been realized.

A. V. Latyshev; A. A. Yushkanov

2010-02-04T23:59:59.000Z

245

On-Line Dissolved Gas Analysis in High-Pressure Fluid-Filled Cables  

Science Conference Proceedings (OSTI)

Highly reliable underground transmission lines are essential to deliver power consistently. Reliability may be affected as underground laminar dielectric cable circuits age and their condition degenerates. High-pressure fluid-filled (HPFF) pipe-type cable systems have been the preferred high-voltage transmission cable type in North America from the earliest transmission cable installations in the 1930s through the late 1990s and still account for the largest percentage (80%) of installed length. Although...

2009-11-17T23:59:59.000Z

246

Investigation of Novel Electrode Materials for Electrochemically-Based Remediation of High- and Low-Level Mixed Wastes in the DOE Complex - Final Report  

DOE Green Energy (OSTI)

New materials are investigated, based on degenerately-doped titanias, for use in the electrochemical degradation of organics and nitrogen-containing compounds in sites of concern to the DOE remediation effort. The data collected in this project appear to provide a rational approach for design of more efficient nanoporous electrodes. Also, osmium complexes appear to be promising candidates for further optimization in operating photo electrochemical cells for solar energy conversion applications.

Lewis, N.S.; Anderson, M.

2000-12-01T23:59:59.000Z

247

Quark-mass dependence of three-flavor QCD at zero and imaginary chemical potential  

E-Print Network (OSTI)

We draw the three-flavor phase diagram as a function of light and strange quark masses for both zero and imaginary quark-number chemical potential, using the Polyakov-loop extended Nambu--Jona-Lasinio model with an effective four-quark vertex depending on the Polyakov loop. The model prediction is consistent with 2+1 flavor lattice QCD prediction at zero chemical potential and with degenerate three-flavor lattice QCD prediction at imaginary chemical potential.

Sasaki, Takahiro; Kouno, Hiroaki; Yahiro, Masanobu

2011-01-01T23:59:59.000Z

248

Probing Radiative Solar Neutrinos Decays  

E-Print Network (OSTI)

Motivated by a pilot experiment conducted by F.Vannucci et al. during a solar eclipse, we work out the geometry governing the radiative decays of solar neutrinos. Surprisingly, although a smaller proportion of the photons can be detected, the case of strongly non-degenerate neutrinos brings better limits in terms of the fundamental couplings. We advocate satellite-based experiments to improve the sensitivity.

Frre, J M

1998-01-01T23:59:59.000Z

249

On the Limits of Information Retrieval in Quantum Mechanics  

E-Print Network (OSTI)

The widely considered assertion is that the unitarity of quantum mechanical evolution assures the preservation of information. It is even promoted in popular literature as an established fact. (Susskind, 2008) Yet, a simple chain of reasoning demonstrates that: 1) almost any evolutionary operator can be well approximated by a degenerate (finite-rank) operator and 2) one needs an eternity to retrieve information exactly from a nonstationary quantum state and to distinguish between arbitrary unitary operator and its finite-dimensional approximations.

Peter B. Lerner

2013-11-26T23:59:59.000Z

250

Photon-photon polarization correlations as a tool for studying parity non-conservation in heliumlike Uranium  

E-Print Network (OSTI)

Due to electron-nucleus weak interaction, atomic bound states with different parities turn out to be mixed. We discuss a prospect for measuring the mixing parameter between the nearly degenerate metastable states 1s_{1/2} 2s_{1/2} : J = 0 and 1s_{1/2} 2p_{1/2} : J = 0 in heliumlike Uranium. Our analysis is based on the polarization properties of the photons emitted in the two-photon decays of such states.

Filippo Fratini; Sergiy Trotsenko; Stanislav Tashenov; Thomas Stoehlker; Andrey Surzhykov

2011-03-23T23:59:59.000Z

251

Low-energy U(1) x USp(2M) gauge theory from simple high-energy gauge group  

E-Print Network (OSTI)

We give an explicit example of the embedding of a near BPS low-energy (U(1) x USp(2M))/Z_2 gauge theory into a high-energy theory with a simple gauge group and adjoint matter content. This system possesses degenerate monopoles arising from the high-energy symmetry breaking as well as non-Abelian vortices due to the symmetry breaking at low energies. These solitons of different codimensions are related by the exact homotopy sequences.

Sven Bjarke Gudnason; Kenichi Konishi

2010-02-04T23:59:59.000Z

252

Cognitive impairment: quantification and possibilities for pharmacological treatment  

E-Print Network (OSTI)

, independence, and mortality. Dopaminergic therapy remediates some of the cognitive symptoms seen in PD. For example, a restorative effect is seen on cognitive tasks that tap into the frontostriatal pathways such as planning on the Tower of London task... is reported in patients receiving dopaminergic treatment, but not in untreated patients (Swainson, Rogers et al. 2000; Cools, Barker et al. 2001). In the earlier stages of the disease process, degeneration of dopaminergic neurons tends to be limited...

Housden, Charlotte R.

2013-04-30T23:59:59.000Z

253

Quark Lepton Similarity  

E-Print Network (OSTI)

We propose the lepton mixing matrix at high energy scale to be connected to quark mixing matrix by the similar transformation. The similarity between CKM and PMNS significantly narrows down the ranges in physical parameters. The condition requires $\\sin\\theta_{13}$ not to be larger than 0.15, masses to be of quasi-degenerate normal ordering, and $\\tan\\beta$ to be large.

Seungsu Hwang; Kim Siyeon

2010-08-20T23:59:59.000Z

254

Density matrix, superconductivity and molecular structure  

Science Conference Proceedings (OSTI)

Starting from Yang`s offdiagonal long-range order concept and the macroscopic occupation condition for the second order density matrix as the basis for condensation phenomena the authors develop the notion that the extremal wave function (EWF), which is related to these conditions, leads to superconductivity in monatomic systems. It is proven that the BCS model and the version where it is projected onto a fixed number of particles possesses EWF properties, differs negligibly from the EWF, and conserves offdiagonal long-range order. The condition for the EWF to be energetically favored is the presence of macroscopic degenerate one-electron energy levels in the system, partial occupation of this degenerate region, and also an effective attraction among the electrons. Considerations are advanced indicating that these conditions are satisfied in the high temperature superconducting metal oxide ceramics, due to the presence of macroscopically degenerate diffusion orbitals distributed among the O{sup -} ions in the CuO{sub 2} layers, and with the effective screening of these layers by the metal-like La, Ba, Y, or O layers. 51 refs., 3 figs., 1 tab.

Mestechkin, M.M.; Klimko, G.T.; Vaiman, G.E. [Academy of Science of the Ukrainian SSR, Donetsk (Russian Federation)

1992-01-01T23:59:59.000Z

255

Generation of polarization entangled photons using type-II doubly periodically poled lithium niobate waveguides  

E-Print Network (OSTI)

In this paper, we address the issue of the generation of non-degenerate cross-polarization-entangled photon pairs using type-II periodically poled lithium niobate. We show that, by an appropriate engineering of the quasi-phase-matching grating, it is possible to simultaneously satisfy the conditions for two spontaneous parametric down-conversion processes, namely ordinary pump photon down-conversion to either extraordinary signal and ordinary idler paired photons, or to ordinary signal and extraordinary idler paired photons. In contrast to single type-II phase-matching, these two processes, when enabled together, can lead to the direct production of cross-polarization-entangled state for non degenerate signal and idler wavelengths. Such a scheme should be of great interest in applications requiring polarization-entangled non degenerate paired photons with, for instance, one of the entangled photons at an appropriate wavelength being used for local operation or for quantum storage in an atomic ensemble, and the other one at the typical wavelength of 1550 nm for propagation through an optical fiber.

K. Thyagarajan; K. Sinha; J. Lugani; S. Ghosh; A. Martin; D. B. Ostrowsky; O. Alibart; S. Tanzilli

2009-10-30T23:59:59.000Z

256

Nuclear Regulatory Commission Issuances, Volume 42, No. 2  

Science Conference Proceedings (OSTI)

This report include the issuances received during the specificed period (August 1995) from the NRC, the Atomic Safety and Licensing Boards, the Administrative Law Judges, and the Decisions on Petitions for Rule Making. In these issuances, the following areas were addressed: (1) Emergency planning at the University of Missouri, (2) Transfer of operating license at Plant Vogtle, (3) Discriminatory action against a whistle-blower at Millstone Units 1 & 2, (4) Regulatory issues related to embittlement and cracking at Oyster Creek, and (5) Age-related deterioration of reactor internals components at Pilgrim.

NONE

1995-08-01T23:59:59.000Z

257

Safety research programs sponsored by Office of Nuclear Regulatory Research. Quarterly progress report, April 1-June 30, 1984. Volume 4, No. 2  

SciTech Connect

The projects reported are the following: High Temperature Reactor Research, SSC Development, Validation and Application, CRBR Balance of Plant Modeling, Thermal-Hydraulic Reactor Safety Experiments, Development of Plant Analyzer, Code Assessment and Application (Transient and LOCA Analyses), Thermal Reactor Code Development (RAMONA-3B), Calculational Quality Assurance in Support of PTS; Stress Corrosion Cracking of PWR Steam Generator Tubing, Probability Based Load Combinations for Design of Category I Structures, Mechanical Piping Benchmark Problems, Identification of Age Related Failure Modes; Analysis of Human Error Data for Nuclear Power Plant Safety Related Events, Human Factors Aspects of Safety/Safeguards Interactions, Emergency Action Levels, and Protective Action Decisionmaking.

Weiss, A.J. (comp.)

1984-11-01T23:59:59.000Z

258

Safety research programs sponsored by Office of Nuclear Regulatory Research. Quarterly progress report, October 1-December 31, 1983. Volume 3, No. 4  

Science Conference Proceedings (OSTI)

The projects reported are the following: High Temperature Reactor Research, SSC Development, Validation and Application, CRBR Balance of Plant Modeling, Thermal-Hydraulic Reactor Safety Experiments, Development of Plant Analyzer, Code Assessment and Application (Transient and LOCA Analyses), Thermal Reactor Code Development (RAMONA-3B), Calculational Quality Assurance in Support of PTS; Stress Corrosion Cracking of PWR Steam Generator Tubing, Bolting Failure Analysis, Probability Based Load Combinations for Design of Category I Structures, Mechanical Piping Benchmark Problems, Identification of Age-Related Failure Modes; Analysis of Human Error Data for Nuclear Power Plant Safety-Related Events, Human Factors in Nuclear Power Plant Safeguards, Emergency Action Levels, and Protective Action Decision Making.

Weiss, A.J. (comp.)

1984-05-01T23:59:59.000Z

259

A methodology for evaluating ``new`` technologies in nuclear power plants  

SciTech Connect

As obsolescence and spare parts issues drive nuclear power plants to upgrade with new technology (such as optical fiber communication systems), the ability of the new technology to withstand stressors present where it is installed needs to be determined. In particular, new standards may be required to address qualification criteria and their application to the nuclear power plants of tomorrow. This paper discusses the failure modes and age-related degradation mechanisms of fiber optic communication systems, and suggests a methodology for identifying when accelerated aging should be performed during qualification testing.

Korsah, K.; Clark, R.L.; Holcomb, D.E.

1994-06-01T23:59:59.000Z

260

Textureless Macula Swelling Detection with Multiple Retinal Fundus Images  

SciTech Connect

Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or Point-of-Care applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyse the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image which are useful in Point-of-Care automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalises the image; second, all available views are registered using non-morphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naiveheight- map of the macula. Results are presented on three sets of synthetic images and two sets of real world images. These preliminary tests show the ability to infer a minimum swelling of 300 microns and to correlate the reconstruction with the swollen location.

Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Tobin Jr, Kenneth William [ORNL; Grisan, Enrico [University of Padua, Padua, Italy; Favaro, Paolo [Heriot-Watt University, Edinburgh; Ruggeri, Alfredo [University of Padua, Padua, Italy; Chaum, Edward [University of Tennessee, Knoxville (UTK)

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Computer-aided research into a natural neural network  

SciTech Connect

While artificial neural networks are being applied to solving problems in signal processing and other domains, much remains to be discovered about how even the simpler biological neural networks function. Studying simpler examples of natural systems promises to advance our understanding of principles of organization of neural tissue wherever it occurs. It also may prove useful in the development of new computer architectures. Accordingly, the authors have begun the study of the macular linear bioaccelerometers, or balance organs of mammals, using the rat as the model for the class. This effort includes creating a computer-based workbench that a scientist can use to generate geometric reconstructions of neural tissue from electron microscope serial sections, to create a functional model of information flow within the neural tissue, and ultimately to generate computer animations to visualize how the network functions. Their work to data is based upon the study of long series of sections in a transmission electron microscope. The sections are photographed and the photographs are assembled into montages. Selected nerves and receptor units synapsing with them (their receptive fields) are next traced onto transparencies from the montages. The tracings, which are cross-sectional contours, are digitized with a tablet and stored in data files on a personal computer. The files are transferred to a high performance graphics workstation, where software has been developed to reconstruct these sets of contours as polygonal objects, display them in wireframe or solid form, and create sequence files that can be used to produce a computer animation on videotape.

Ross, M.D.; Cutler, L.; Meyer, G.; Lam, T.; Or, W.

1988-09-01T23:59:59.000Z

262

DOI 10.1007/s12245-010-0183-y CLINICAL IMAGES Early recognition and management of Lyme carditis  

E-Print Network (OSTI)

A 20-year-old man presented to the emergency department with 2 weeks of migratory arthralgias and several macular blanching rashes. A photograph taken by the patient upon initial eruption of the rash was presented during evaluation (Fig. 1). The lesions were suspicious for erythema migrans (Fig. 2). Upon review of systems, the patient earlier reported a brief episode of palpitations. Electrocardiogram revealed first-degree atrioventricular (AV) block (PR interval 320 ms). He was admitted for telemetry monitoring and intravenous ceftriaxone. He developed asymptomatic Wenckebach which progressed to a high-grade second-degree AV block (Fig. 3). Echocardiography showed global ventricular dysfunction (ejection fraction of 35%). Cardiac magnetic resonance imaging (MRI) revealed inflammation around the AV node (Fig. 4). Lyme carditis was confirmed after Western blot revealed Borrelia burgdorferi antibodies. The patient had resolution of symptoms 4 weeks after intravenous ceftriaxone treatment. Follow-up echocardiography, 5 months later, revealed normal left ventricular function (ejection fraction of 55%). Patients with PR intervals greater than 300 ms are at risk for developing high-grade heart block [1, 2]. They can progress from first-degree heart block into complete Fig. 1 Mobile phone image of erythema migrans at time of initial eruption

Pholaphat Charles Inboriboon; P. C. Inboriboon

2010-01-01T23:59:59.000Z

263

Recommendations for the treatment of aging in standard technical specifications  

Science Conference Proceedings (OSTI)

As part of the US Nuclear Regulatory Commission`s Nuclear Plant Aging Research Program, Pacific Northwest Laboratory (PNL) evaluated the standard technical specifications for nuclear power plants to determine whether the current surveillance requirements (SRs) were effective in detecting age-related degradation. Nuclear Plant Aging Research findings for selected systems and components were reviewed to identify the stressors and operative aging mechanisms and to evaluate the methods available to detect, differentiate, and trend the resulting aging degradation. Current surveillance and testing requirements for these systems and components were reviewed for their effectiveness in detecting degraded conditions and for potential contributions to premature degradation. When the current surveillance and testing requirements appeared ineffective in detecting aging degradation or potentially could contribute to premature degradation, a possible deficiency in the SRs was identified that could result in undetected degradation. Based on this evaluation, PNL developed recommendations for inspection, surveillance, trending, and condition monitoring methods to be incorporated in the SRs to better detect age- related degradation of these selected systems and components.

Orton, R.D.; Allen, R.P.

1995-09-01T23:59:59.000Z

264

A Review of Information for Managing Aging in Nuclear Power Plants  

SciTech Connect

Age related degradation effects in safety related systems of nuclear power plants should be managed to prevent safety margins from eroding below the acceptable limits provided in plant design bases. The Nuclear Plant Aging Research (NPAR) Pro- gram, conducted under the auspices of the U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, and other related aging management programs are developing technical information on managing aging. The aging management process central to these efforts consists of three key elements: 1) selecting structures, systems, and components (SSCs) in which aging should be controlled; 2) understanding the mechanisms and rates of degradation in these SSCs; and 3) managing degradation through effective inspection, surveillance, condition monitoring, trending, record keeping, mainten- ance, refurbishment, replacement, and adjustments in the operating environment and service conditions. This document concisely reviews and integrates information developed under the NPAR Program and other aging management studies and other available information related to understanding and managing age-related degradation effects and provides specific refer- ences to more comprehensive information on the same subjects.

WC Morgan; JV Livingston

1995-09-01T23:59:59.000Z

265

Transport of Magnetic Fields in Convective, Accreting Supernova Cores  

E-Print Network (OSTI)

We consider the amplification and transport of a magnetic field in the collapsed core of a massive star, including both the region between the neutrinosphere and the shock, and the central, opaque core. An analytical argument explains why rapid convective overturns persist within a newly formed neutron star for roughly 10 seconds ($> 10^3$ overturns), consistent with recent numerical models. A dynamical balance between turbulent and magnetic stresses within this convective layer corresponds to flux densities in excess of $10^{15}$G. Material accreting onto the core is heated by neutrinos and also becomes strongly convective. We compare the expected magnetic stresses in this convective `gain layer' with those deep inside the neutron core. Buoyant motions of magnetized fluid are greatly aided by the intense neutrino flux. We calculate the transport rate through a medium containing free neutrons protons, and electrons, in the limiting cases of degenerate or non-degenerate nucleons. Fields stronger than $\\sim 10^{13}$ G are able to rise through the outer degenerate layers of the neutron core during the last stages of Kelvin-Helmholtz cooling (up to 10 seconds post-collapse), even though these layers have become stable to convection. We also find the equilibrium shape of a thin magnetic flux rope in the dense hydrostatic atmosphere of the neutron star, along with the critical separation of the footpoints above which the rope undergoes unlimited expansion against gravity. The implications of these results for pulsar magnetism are summarized, and applied to the case of late fallback over the first 1,000-10,000 s of the life of a neutron star

Christopher Thompson; Norman Murray

2001-05-24T23:59:59.000Z

266

ALSNews Vol. 345  

NLE Websites -- All DOE Office Websites (Extended Search)

5 Print 5 Print A Spintronic Semiconductor with Selectable Charge Carriers 278 thumb Researchers found a semiconductor with two properties crucial for spintronics: a large Rashba effect (splitting of degenerate spin states) and ambipolarity (conduction via electrons and holes). Furthermore, it is possible to control whether the charge carriers are electrons or holes by engineering the surface layer. Read more... Contact: Luca Moreschini From Protein Structure to Function: Ring Cycle for Dilating and Constricting the Nuclear Pore 277thumb Nuclear pore complexes (NPCs) serve as gatekeepers between a cell's cytoplasm and its nucleus. Through crystallographic analyses at the ALS, researchers have elucidated the molecular architecture of the NPC transport channel. Read more...

267

Observation of a Two-Dimensional Fermi Gas of Atoms  

Science Conference Proceedings (OSTI)

We have prepared a degenerate gas of fermionic atoms which move in two dimensions while the motion in the third dimension is 'frozen' by tight confinement and low temperature. In situ imaging provides direct measurement of the density profile and temperature. The gas is confined in a defect-free optical potential, and the interactions are widely tunable by means of a Fano-Feshbach resonance. This system can be a starting point for exploration of 2D Fermi physics and critical phenomena in a pure, controllable environment.

Martiyanov, Kirill; Makhalov, Vasiliy; Turlapov, Andrey [Institute of Applied Physics, Russian Academy of Sciences, ul. Ulyanova 46, Nizhniy Novgorod, 603000 (Russian Federation)

2010-07-16T23:59:59.000Z

268

Benchmark 3-Flavor Pattern and Small Universal Flavor-Electroweak Parameter  

E-Print Network (OSTI)

The electroweak theory contains too many empirical parameters. Most of them are related to the flavor part of particle physics. In this paper we discuss a relevant simple idea: the complicated system of actual dimensionless, small versus large, quantities in elementary particle flavor phenomenology is small deviated from an explicitly defined benchmark flavor pattern with no tuning parameters. One small empirical universal dimensionless parameter measures this deviation. Its possible physical connections are discussed. As inferences, quasi-degenerate neutrino type with mass scale m = 0.16-0.18 eV, neutrino and quark mixing matrices, large neutrino oscillation 3-flavor hierarchy and quark-neutrino complementarity are predicted.

E. M. Lipmanov

2008-12-08T23:59:59.000Z

269

Electronic Structure of Dense Plasmas by X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Rogers, F J; Pollaine, S M; Froula, D H; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R; Landen, O L

2003-10-07T23:59:59.000Z

270

Electronic Structure Measurement of Solid Density Plasmas using X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Rogers, F J; Landen, O L; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R

2003-08-23T23:59:59.000Z

271

Investigation of the Electronic Structure of Solid Density Plasmas by X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Forest, F J; Kuhlbrodt, S; Redmer, R; Faussurier, G; Blancard, C; Renaudin, P; Landen, O L

2003-05-19T23:59:59.000Z

272

ALSNews Vol. 345  

NLE Websites -- All DOE Office Websites (Extended Search)

5 Print 5 Print A Spintronic Semiconductor with Selectable Charge Carriers 278 thumb Researchers found a semiconductor with two properties crucial for spintronics: a large Rashba effect (splitting of degenerate spin states) and ambipolarity (conduction via electrons and holes). Furthermore, it is possible to control whether the charge carriers are electrons or holes by engineering the surface layer. Read more... Contact: Luca Moreschini From Protein Structure to Function: Ring Cycle for Dilating and Constricting the Nuclear Pore 277thumb Nuclear pore complexes (NPCs) serve as gatekeepers between a cell's cytoplasm and its nucleus. Through crystallographic analyses at the ALS, researchers have elucidated the molecular architecture of the NPC transport channel. Read more...

273

ALSNews Vol. 345  

NLE Websites -- All DOE Office Websites (Extended Search)

5 Print 5 Print A Spintronic Semiconductor with Selectable Charge Carriers 278 thumb Researchers found a semiconductor with two properties crucial for spintronics: a large Rashba effect (splitting of degenerate spin states) and ambipolarity (conduction via electrons and holes). Furthermore, it is possible to control whether the charge carriers are electrons or holes by engineering the surface layer. Read more... Contact: Luca Moreschini From Protein Structure to Function: Ring Cycle for Dilating and Constricting the Nuclear Pore 277thumb Nuclear pore complexes (NPCs) serve as gatekeepers between a cell's cytoplasm and its nucleus. Through crystallographic analyses at the ALS, researchers have elucidated the molecular architecture of the NPC transport channel. Read more...

274

On the breakup of air bubbles in Hele-Shaw cell  

E-Print Network (OSTI)

We study the problem of breakup of an air bubble in a Hele-Shaw cell. In particular, we propose some sufficient conditions of breakup of the bubble, and ways to find the contraction points of its parts. We also study regulated contraction of a pair of bubbles (in which the rates of air extraction from the bubbles is controlled), and study various asymptotic questions (such as the asymptotics of contraction of a bubble to a degenerate critical point, and asymptotics of contraction of a small bubble in presence of a big bubble).

Vladimir Entov; Pavel Etingof

2008-04-30T23:59:59.000Z

275

Comparative Study of Ultimate Saturation Velocity in Zigzag and Chiral Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Charge transfer mechanism in carbon nanotubes (CNTs) from the scattering-limited Ohmic transport to high-field-initiated ballistic transport is studied. It is shown that the electrons changes their motion from randomness (in equilibrium) to streamlined one (in non-equilibrium) when high electric field is applied. The intrinsic velocity is discussed in non-parabolic semiconducting limits considering the nondegenerate and degenerate situations. The results obtained are significant in extracting carrier transport properties from experimental data on CNTs and in understanding the fundamental processes controlling the charge transport in nanoscale devices.

Chek, Desmond C. Y.; Hashim, Abdul Manaf [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Tan, Michael Loong Peng [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Electrical Engineering Division, Engineering Department, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Arora, Vijay K. [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Division of Engineering and Physics, Wilkes University, Wilkes-Barre, PA 18766 (United States)

2011-05-25T23:59:59.000Z

276

Cosmological mass limits on neutrinos, axions, and other light particles  

E-Print Network (OSTI)

The small-scale power spectrum of the cosmological matter distribution together with other cosmological data provides a sensitive measure of the hot dark matter fraction, leading to restrictive neutrino mass limits. We extend this argument to generic cases of low-mass thermal relics. We vary the cosmic epoch of thermal decoupling, the radiation content of the universe, and the new particle's spin degrees of freedom. Our treatment covers various scenarios of active plus sterile neutrinos or axion-like particles. For three degenerate massive neutrinos, we reproduce the well-known limit of m_nu solar eV-mass axions to be discovered by the CAST experiment.

Steen Hannestad; Georg Raffelt

2003-12-11T23:59:59.000Z

277

Shape Coexistence and Mixing in 152Sm  

E-Print Network (OSTI)

Experimental studies of 152Sm using multiple-step Coulomb excitation and inelastic neutron scattering provide key data that clarify the low-energy collective structure of this nucleus. No candidates for two-phonon beta-vibrational states are found. Experimental level energies of the ground-state and first excited (0+ state) rotational bands, electric monopole transition rates, reduced quadrupole transition rates, and the isomer shift of the first excited 2+ state are all described within ~10% precision using two-band mixing calculations. The basic collective structure of 152Sm is described using strong mixing of near-degenerate coexisting quasi-rotational bands with different deformations.

Kulp, W D; Garrett, P E; Wu, C Y; Cline, D; Allmond, J M; Bandyopadhyay, D; Dashdorj, D; Choudry, S N; Hayes, A B; Hua, H; Lesher, S; Mynk, M; McEllistrem, M T; McKay, C J; Orce, J C; Teng, R; Yates, S W

2007-01-01T23:59:59.000Z

278

Shape Coexistence and Mixing in 152Sm  

E-Print Network (OSTI)

Experimental studies of 152Sm using multiple-step Coulomb excitation and inelastic neutron scattering provide key data that clarify the low-energy collective structure of this nucleus. No candidates for two-phonon beta-vibrational states are found. Experimental level energies of the ground-state and first excited (0+ state) rotational bands, electric monopole transition rates, reduced quadrupole transition rates, and the isomer shift of the first excited 2+ state are all described within ~10% precision using two-band mixing calculations. The basic collective structure of 152Sm is described using strong mixing of near-degenerate coexisting quasi-rotational bands with different deformations.

W. D. Kulp; J. L. Wood; P. E. Garrett; C. Y. Wu; D. Cline; J. M. Allmond; D. Bandyopadhyay; D. Dashdorj; S. N. Choudry; A. B. Hayes; H. Hua; S. R. Lesher; M. Mynk; M. T. McEllistrem; C. J. McKay; J. N. Orce; R. Teng; S. W. Yates

2007-06-28T23:59:59.000Z

279

Thermodynamic properties and electrical conductivity of strongly correlated plasma media  

E-Print Network (OSTI)

We study thermodynamic properties and the electrical conductivity of dense hydrogen and deuterium using three methods: classical reactive Monte Carlo (REMC), direct path integral Monte Carlo (PIMC) and a quantum dynamics method in the Wigner representation of quantum mechanics. We report the calculation of the deuterium compression quasi-isentrope in good agreement with experiments. We also solve the Wigner-Liouville equation of dense degenerate hydrogen calculating the initial equilibrium state by the PIMC method. The obtained particle trajectories determine the momentum-momentum correlation functions and the electrical conductivity and are compared with available theories and simulations.

Filinov, V S; Boţan, A V; Bonitz, M; Fortov, V E

2008-01-01T23:59:59.000Z

280

Role of Magnetic Interaction in Dense Plasma  

E-Print Network (OSTI)

Quasiparticle excitations and associated phenomena of energy and momentum transfer rates have been calculated in terms of the drag and the diffusion coefficients exposing clearly the dominance of the magnetic interaction over its electric counterpart. The results have been compared with the finite temperature results highlighting the similarities and dissimilarities in the two extreme regimes of temperature and density. Non-Fermi-liquid behavior of various physical quantities like neutrino mean free path and thermal relaxation time due to the inclusion of magnetic interaction has clearly been revealed. All the results presented in the current review are pertinent to the degenerate and ultradegenerate plasma.

S. Sarkar; K. Pal; A. K. Dutt-Mazumder

2013-07-22T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

High-fidelity transmission of polarization encoded qubits from an entangled source over 100 km of fiber  

E-Print Network (OSTI)

We demonstrate non-degenerate down-conversion at 810 and 1550 nm for long-distance fiber based quantum communication using polarization entangled photon pairs. Measurements of the two-photon visibility, without dark count subtraction, have shown that the quantum correlations (raw visibility 89%) allow secure quantum cryptography after 100 km of non-zero dispersion shifted fiber using commercially available single photon detectors. In addition, quantum state tomography has revealed little degradation of state negativity, decreasing from 0.99 at the source to 0.93 after 100 km, indicating minimal loss in fidelity during the transmission.

Hbel, Hannes; Lederer, Thomas; Blauensteiner, Bibiane; Lornser, Thomas; Poppe, Andreas; Zeilinger, Anton

2008-01-01T23:59:59.000Z

282

High-fidelity transmission of polarization encoded qubits from an entangled source over 100 km of fiber  

E-Print Network (OSTI)

We demonstrate non-degenerate down-conversion at 810 and 1550 nm for long-distance fiber based quantum communication using polarization entangled photon pairs. Measurements of the two-photon visibility, without dark count subtraction, have shown that the quantum correlations (raw visibility 89%) allow secure quantum cryptography after 100 km of non-zero dispersion shifted fiber using commercially available single photon detectors. In addition, quantum state tomography has revealed little degradation of state negativity, decreasing from 0.99 at the source to 0.93 after 100 km, indicating minimal loss in fidelity during the transmission.

Hannes Hbel; Michael R. Vanner; Thomas Lederer; Bibiane Blauensteiner; Thomas Lornser; Andreas Poppe; Anton Zeilinger

2008-01-23T23:59:59.000Z

283

Inductive entanglement classification of four qubits under stochastic local operations and classical communication  

Science Conference Proceedings (OSTI)

Using an inductive approach to classify multipartite entangled states under stochastic local operations and classical communication introduced recently by the authors [Phys. Rev. A 74, 052336 (2006)], we give the complete classification of four-qubit entangled pure states. Apart from the expected degenerate classes, we show that there exist eight inequivalent ways to entangle four qubits. In this respect, permutation symmetry is taken into account and states with a structure differing only by parameters inside a continuous set are considered to belong to the same class.

Lamata, L.; Leon, J. [Instituto de Matematicas y Fisica Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Salgado, D. [Dpto. Fisica Teorica, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain); Solano, E. [Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado Postal 1761, Lima (Peru)

2007-02-15T23:59:59.000Z

284

Optimized sympathetic cooling of atomic mixtures via fast adiabatic strategies  

SciTech Connect

We discuss fast frictionless cooling techniques in the framework of sympathetic cooling of cold atomic mixtures. It is argued that optimal cooling of an atomic species--in which the deepest quantum degeneracy regime is achieved--may be obtained by means of sympathetic cooling with another species whose trapping frequency is dynamically changed to maintain constancy of the Lewis-Riesenfeld adiabatic invariant. Advantages and limitations of this cooling strategy are discussed, with particular regard to the possibility of cooling Fermi gases to a deeper degenerate regime.

Choi, Stephen; Sundaram, Bala [Department of Physics, University of Massachusetts, Boston, Massachusetts 02125 (United States); Onofrio, Roberto [Dipartimento di Fisica ''Galileo Galilei'', Universita di Padova, Via Marzolo 8, Padova I-35131 (Italy); Department of Physics, University of Massachusetts, Boston, Massachusetts 02125 (United States); Institute for Theoretical Atomic, Molecular and Optical Physics (ITAMP), Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)

2011-11-15T23:59:59.000Z

285

Equation of state measurements at extreme pressures using laser-driven shocks  

Science Conference Proceedings (OSTI)

The regime of high density and extreme pressure in hydrogen is very difficult to approach theoretically since it is a strongly correlated, partially degenerate composite of molecules, atoms, and electrons. For this reason, a number of theoretical models of the EOS of hydrogen have been proposed. This makes reliable experimental data essential as a guide to theory. We have accessed this regime by shocking liquid D2 to pressures at and above the metallic transition where we measured the thermodynamic properties of the shocked state.

Cauble, R C; Celliers, P M; Collins, G W; DaSilva, L B; Gold, D M

1998-12-03T23:59:59.000Z

286

Energy conditions in $f(R,L_{m})$ gravity  

E-Print Network (OSTI)

In order to constrain $f(R,L_{m})$ gravity from theoretical aspects, its energy conditions are derived in this paper. These energy conditions given by us are quite general and can be degenerated to the well-known energy conditions in General Relativity and $f(R)$ theories of gravity with arbitrary coupling, non-minimal coupling and non-coupling between matter and geometry, respectively, as special cases. To exemplify how to use these energy conditions to restrict $f(R,L_{m})$ gravity, we consider a special model in the FRW cosmology and give some corresponding results by using astronomical observations.

Wang, Jun

2012-01-01T23:59:59.000Z

287

An Anzatz about Gravity, Cosmology, and the Pioneer Anomaly  

Science Conference Proceedings (OSTI)

The Pulsar 1913+16 binary system may represent a young binary system where previously it is claimed that the dynamics are due to either a third body or a gravitational vortex. Usually a binary systems trajectory could reside in a single ellipse or circular orbit; the double ellipse implies that the 1913+16 system may be starting to degenerate into a single elliptical trajectory. This could be validated only after a considerably long time period. In a majority of binary star systems

Paul Murad

2010-01-01T23:59:59.000Z

288

Thermal Gravitational Waves from Primordial Black Holes  

E-Print Network (OSTI)

Thermal gravitational waves can be generated in various sources such as, in the cores of stars, white dwarfs and neutron stars due to the fermion collisions in the dense degenerate Fermi gas. Such high frequency thermal gravitational waves can also be produced during the collisions in a gamma ray burst or during the final stages of the evaporation of primordial black holes. Here we estimate the thermal gravitational waves from primordial black holes and estimate the integrated energy of the gravitational wave emission over the entire volume of the universe and over Hubble time. We also estimate the gravitational wave flux from gamma ray bursts and jets.

C. Sivaram; Kenath Arun

2010-05-19T23:59:59.000Z

289

OUTP 9424P Reconciling the LEP and SLAC measurements of sin 2 ?w  

E-Print Network (OSTI)

We consider whether a discrepancy between the SLAC and LEP measurements of sin 2 ?w can be explained by new physics. We find that only the contribution of a new neutral gauge boson, Z ? , nearly degenerate with the Z can affect the SLAC measurement while leaving the LEP observables almost unaffected. We briefly discuss possible signals for this new gauge boson, including changes in the Z lineshape when measured with polarised electrons, small changes in Rb, Ae FB, and larger changes in two jet and tt production at hadron colliders.

Francesco Caravaglios A; Graham G. Ross B

1994-01-01T23:59:59.000Z

290

Reconciling the LEP and Slac Measurements of Sin^2(?_W)  

E-Print Network (OSTI)

We consider whether a discrepancy between the SLAC and LEP measurements of $\\Sw$ can be explained by new physics. We find that only the contribution of a new neutral gauge boson, $Z^\\prime$, nearly degenerate with the Z can affect the SLAC measurement while leaving the LEP observables almost unaffected. We briefly discuss possible signals for this new gauge boson, including changes in the $Z$ lineshape when measured with polarised electrons, small changes in $R_b$, $A^e_{FB}$, and larger changes in two jet and $t\\bar{t}$ production at hadron colliders.

F. Caravaglios; G. G. Ross

1994-10-19T23:59:59.000Z

291

The structure of Green functions in quantum field theory with a general state  

E-Print Network (OSTI)

In quantum field theory, the Green function is usually calculated as the expectation value of the time-ordered product of fields over the vacuum. In some cases, especially in degenerate systems, expectation values over general states are required. The corresponding Green functions are essentially more complex than in the vacuum, because they cannot be written in terms of standard Feynman diagrams. Here, a method is proposed to determine the structure of these Green functions and to derive nonperturbative equations for them. The main idea is to transform the cumulants describing correlations into interaction terms.

Christian Brouder

2007-10-30T23:59:59.000Z

292

Green formula in Hall algebras and cluster algebras  

E-Print Network (OSTI)

The objective of the present paper is to give a survey of recent progress on applications of the approaches of Ringel-Hall type algebras to quantum groups and cluster algebras via various forms of Green's formula. In this paper, three forms of Green's formula are highlighted, (1) the original form of Green's formula \\cite{Green}\\cite{RingelGreen}, (2) the degeneration form of Green's formula \\cite{DXX} and (3) the projective form of Green's formula \\cite{XX2007a} i.e. Green formula with a $\\bbc^{*}$-action.

Xiao, Jie

2008-01-01T23:59:59.000Z

293

Two EGARCH models and one fat tail  

E-Print Network (OSTI)

;1: Extensions to higher order models, components, seasonals and explanatory variables are discussed in Harvey (2013, ch 4). The above model belongs to the EGARCH class introduced by Nelson (1991). The usual formulation has ut replaced by j"tj. Moments of yt... ; 1; (22) it can be seen5 that when #24; = & = 0; p 2 j#15;tj #0; 1 and, when #24; = & ! 1; 5When #24; = 0, #24;h = p 2 and bt degenerates to a Bernoulli variable such that bt = 0 when #15;t 0. Then 2bt #0; 1 = 1 (#0...

Harvey, Andrew; Caivano, Michele

2013-07-29T23:59:59.000Z

294

Information content in the halo-model dark-matter power spectrum II: Multiple cosmological parameters  

E-Print Network (OSTI)

We investigate the cosmological Fisher information in the non-linear dark-matter power spectrum in the context of the halo model. We find that there is a plateau in information content on translinear scales which is generic to all cosmological parameters we tried. There is a rise in information on smaller scales, but we find that it is quite degenerate among different cosmological parameters (except, perhaps, the tilt). This suggests that it could be difficult to constrain cosmological parameters using the non-linear regime of the dark-matter power spectrum. We suggest ways to get around this problem, such as removing the largest haloes from consideration in survey analysis.

Mark C. Neyrinck; Istvn Szapudi

2006-10-06T23:59:59.000Z

295

Detecting exotic heavy leptons at the large hadron collider.  

E-Print Network (OSTI)

ar X iv :h ep -p h/ 01 08 09 7v 1 1 0 A ug 2 00 1 Preprint typeset in JHEP style. - HYPER VERSION Cavendish-HEP-01/10 DAMTP-2001-71 CERN-TH/2001-205 Detecting Exotic Heavy Leptons at the Large Hadron Collider B.C. Allanach?, C.M. Harris, M... , CB3 0WA, UK. Abstract: New almost-degenerate charged and neutral heavy leptons are a feature of a number of theories of physics beyond the Standard Model. The prospects for detecting these at the Large Hadron Collider using a time-of-flight technique...

Allanach, B C; Harris, Chris M; Parker, Michael A; Richardson, P; Webber, Bryan R

296

A Haar component for quantum limits on locally symmetric spaces  

E-Print Network (OSTI)

We prove lower bounds for the entropy of limit measures associated to non-degenerate sequences of eigenfunctions on locally symmetric spaces of non-positive curvature. In the case of certain compact quotients of the space of positive definite $n\\times n$ matrices (any quotient for $n=3$, quotients associated to inner forms in general), measure classification results then show that the limit measures must have a Lebesgue component. This is consistent with the conjecture that the limit measures are absolutely continuous.

Anantharaman, Nalini

2010-01-01T23:59:59.000Z

297

On subnormal solutions of periodic non-homogeneous linear differential equations, special functions and special polynomials  

E-Print Network (OSTI)

This paper offers a new and complete description of subnormal solutions of certain non-homogeneous second order periodic linear differential equations first studied by Gundersen and Steinbart in 1994. We have established a previously unknown relation that the general solutions (\\textit{i.e.}, whether subnormal or not) of the DEs can be solved explicitly in terms of classical special functions, namely the Bessel, Lommel and Struve functions, which are important because of their numerous physical applications. In particular, we show that the subnormal solutions are written explicitly in terms of the degenerate Lommel functions $S_{\\mu, \

Chiang, Y M

2009-01-01T23:59:59.000Z

298

Convergence of a Finite Volume Scheme for Gas Water Flow in a Multi-Dimensional Porous Media  

E-Print Network (OSTI)

A classical model for water-gas flows in porous media is considered. The degenerate coupled system of equations obtained by mass conservation is usually approximated by finite volume schemes in the oil reservoir simulations. The convergence properties of these schemes are only known for incompressible fluids. This chapter deals with construction and convergence analysis of a finite volume scheme for compressible and immiscible flow in porous media. In comparison with incompressible fluid, compressible fluids requires more powerful techniques. We present a new result of convergence in a two or three dimensional porous medium and under the only modification that the density of gas depends on global pressure.

Bendahmane, Mostafa; Saad, Mazen

2011-01-01T23:59:59.000Z

299

The Cauchy problem for a quasilinear parabolic equation with gradient absorption  

SciTech Connect

The qualitative properties of solutions to the Cauchy problem for a degenerate parabolic equation containing a nonlinear operator of Baouendi-Grushin type and with gradient absorption whose density depends on time, as well as the space variables, are investigated. Bounds for the diameter of the support of the solution which are sharp with respect to time are obtained, together with its maximum. A condition which determines whether or not the phenomenon of decay to zero of the total mass of the solution occurs is discovered. Bibliography: 35 titles.

Markasheva, Vera A; Tedeev, Anatoli F [Institute of Applied Mathematics and Mechanics, Ukraine National Academy of Sciences, Donetsk (Ukraine)

2012-04-30T23:59:59.000Z

300

Nano-displacement measurements using spatially multimode squeezed light  

E-Print Network (OSTI)

We demonstrate the possibility of surpassing the quantum noise limit for simultaneous multi-axis spatial displacement measurements that have zero mean values. The requisite resources for these measurements are squeezed light beams with exotic transverse mode profiles. We show that, in principle, lossless combination of these modes can be achieved using the non-degenerate Gouy phase shift of optical resonators. When the combined squeezed beams are measured with quadrant detectors, we experimentally demonstrate a simultaneous reduction in the transverse x- and y- displacement fluctuations of 2.2 dB and 3.1 dB below the quantum noise limit.

N. Treps; N. Grosse; W. P. Bowen; M. T. L. Hsu; A. Maitre; C. Fabre; H. -A. Bachor; P. K. Lam

2003-11-19T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Color superconductivity in ultra-dense quark matter  

E-Print Network (OSTI)

At ultra-high density, matter is expected to form a degenerate Fermi gas of quarks in which there is a condensate of Cooper pairs of quarks near the Fermi surface. This phenomenon is called color superconductivity. In these proceedings I review the underlying physics of color superconductivity and our current understanding of the possible phases of real-world quark matter. Then I consider how lattice gauge theorists would proceed to investigate the phase structure of dense quark matter if it were possible to perform the path integral numerically, i.e. if the sign problem had been solved.

Mark G. Alford

2006-10-06T23:59:59.000Z

302

Sterile neutrinos in the 3+s scenario and solar data  

E-Print Network (OSTI)

The flatness of the SuperKamiokande neutrino electron scattering spectrum and the apparent downturn of the charged current spectrum in the SNO data which the Large Mixing Angle solution (LMA) to the solar neutrino problem fails to predict are analysed in the context of an extension to the standard electroweak model with light sterile neutrinos. It is found that a sterile neutrino which is quasi degenerate with the active ones with $\\Delta m^2_{41}=10^{-5}eV^2$ and mixing $sin\\theta_{14}=0.04$ provides a suitable improvement to the LMA data fits.

Pulido, Joao

2013-01-01T23:59:59.000Z

303

Sterile neutrinos in the 3+s scenario and solar data  

E-Print Network (OSTI)

The flatness of the SuperKamiokande neutrino electron scattering spectrum and the apparent downturn of the charged current spectrum in the SNO data which the Large Mixing Angle solution (LMA) to the solar neutrino problem fails to predict are analysed in the context of an extension to the standard electroweak model with light sterile neutrinos. It is found that a sterile neutrino which is quasi degenerate with the active ones with $\\Delta m^2_{41}=10^{-5}eV^2$ and mixing $sin\\theta_{14}=0.04$ provides a suitable improvement to the LMA data fits.

Joao Pulido; C. R. Das

2013-10-01T23:59:59.000Z

304

Black soliton in a quasi-one-dimensional trapped fermion-fermion mixture  

E-Print Network (OSTI)

Employing a time-dependent mean-field-hydrodynamic model we study the generation of black solitons in a degenerate fermion-fermion mixture in a cigar-shaped geometry using variational and numerical solutions. The black soliton is found to be the first stationary vibrational excitation of the system and is considered to be a nonlinear continuation of the vibrational excitation of the harmonic oscillator state. We illustrate the stationary nature of the black soliton, by studying different perturbations on it after its formation.

Sadhan K. Adhikari

2006-07-06T23:59:59.000Z

305

Fusion rules and vortices in $p_x+ip_y$ superconductors  

E-Print Network (OSTI)

The "half-quantum" vortices ($\\sigma$) and quasiparticles ($\\psi$) in a two-dimensional $p_x+ip_y$ superconductor obey the Ising-like fusion rules $\\psi\\times \\psi=1$, $\\sigma\\times \\psi=\\sigma$, and $\\sigma\\times \\sigma= 1+\\psi$. We explain how the physical fusion of vortex-antivortex pairs allows us to use these rules to read out the information encoded in the topologically protected space of degenerate ground states. We comment on the potential applicability of this fact to quantum computation. Modified 11/30/05 to reflect manuscript as accepted for publication. Includes corrected last section.

Michael Stone; Suk Bum Chung

2005-05-20T23:59:59.000Z

306

Nucleon excited states on the lattice  

E-Print Network (OSTI)

We study the pion-nucleon system in s-wave in the framework of lattice QCD in order to gain new information on the nucleon excited states. We perform simulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266 MeV. The results show that including the two-particle states drastically changes the energy levels. The variational analysis and the distillation approach play an important role in the extraction of the energy levels. The phase shift analysis allows to extract information on the resonance nature of the observed states.

C. B. Lang; V. Verduci

2013-04-15T23:59:59.000Z

307

Nucleon excited states on the lattice  

E-Print Network (OSTI)

We study the pion-nucleon system in s-wave in the framework of lattice QCD in order to gain new information on the nucleon excited states. We perform simulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266 MeV. The results show that including the two-particle states drastically changes the energy levels. The variational analysis and the distillation approach play an important role in the extraction of the energy levels. The phase shift analysis allows to extract information on the resonance nature of the observed states.

Lang, C B

2013-01-01T23:59:59.000Z

308

ALSNews Vol. 345  

NLE Websites -- All DOE Office Websites (Extended Search)

5 Print 5 Print A Spintronic Semiconductor with Selectable Charge Carriers 278 thumb Researchers found a semiconductor with two properties crucial for spintronics: a large Rashba effect (splitting of degenerate spin states) and ambipolarity (conduction via electrons and holes). Furthermore, it is possible to control whether the charge carriers are electrons or holes by engineering the surface layer. Read more... Contact: Luca Moreschini From Protein Structure to Function: Ring Cycle for Dilating and Constricting the Nuclear Pore 277thumb Nuclear pore complexes (NPCs) serve as gatekeepers between a cell's cytoplasm and its nucleus. Through crystallographic analyses at the ALS, researchers have elucidated the molecular architecture of the NPC transport channel. Read more...

309

Frustration, Entanglement, and Correlations in Quantum Many Body Systems  

E-Print Network (OSTI)

We derive an exact lower bound to a universal measure of frustration in degenerate ground states of quantum many-body systems. The bound results in the sum of two contributions: entanglement and classical correlations arising from local measurements. We show that average frustration properties are completely determined by the behavior of the maximally mixed ground state. We identify sufficient conditions for a quantum spin system to saturate the bound, and for models with twofold degeneracy we prove that average and local frustration coincide.

U. Marzolino; S. M. Giampaolo; F. Illuminati

2013-02-25T23:59:59.000Z

310

Covariant Derivatives on Null Submanifolds  

E-Print Network (OSTI)

The degenerate nature of the metric on null hypersurfaces makes it difficult to define a covariant derivative on null submanifolds. Recent approaches using decomposition to define a covariant derivative on null hypersurfaces are investigated, with examples demonstrating the limitations of the methods. Motivated by Geroch's work on asymptotically flat spacetimes, conformal transformations are used to construct a covariant derivative on null hypersurfaces, and a condition on the Ricci tensor is given to determine when this construction can be used. Several examples are given, including the construction of a covariant derivative operator for the class of spherically symmetric hypersurfaces.

Don Hickethier; Tevian Dray

2011-08-11T23:59:59.000Z

311

The light stop window  

E-Print Network (OSTI)

We show that a right-handed stop in the 200-400 GeV mass range, together with a nearly degenerate neutralino and, possibly, a gluino below 1.5 TeV, follows from reasonable assumptions, is consistent with present data, and offers interesting discovery prospects at the LHC. Triggering on an extra jet produced in association with stops allows the experimental search for stops even when their mass difference with neutralinos is very small and the decay products are too soft for direct observation. Using a razor analysis, we are able to set stop bounds that are stronger than those published by ATLAS and CMS.

Antonio Delgado; Gian F. Giudice; Gino Isidori; Maurizio Pierini; Alessandro Strumia

2012-12-31T23:59:59.000Z

312

Atomic structure and magnetic properties of Fe1-xCox alloys  

SciTech Connect

Using genetic algorithm with first-principle calculations, we searched for low-energy crystal structures of Fe1?xCox alloys. We found that Fe1?xCox alloys are highly configurationally degenerate with many additional off-stoichiometric stable structures to the well-known B2 structure. The average magnetic moment of Fe atom increases with concentration of Co in the alloy, while that of Co atom is almost constant, which are consistent with experiments and earlier studies. The magnetic moment of Fe atom is strongly dependent on the number of Co nearest neighbor and it increases with this number.

Nguyen, Manh Cuong; Zhao, Xin; Ji, Min; Wang, Cai-Zhuang; Harmon, Bruce; Ho, Kai-Ming

2012-03-09T23:59:59.000Z

313

SELF-SHIELDING OF SOFT X-RAYS IN TYPE Ia SUPERNOVA PROGENITORS  

SciTech Connect

There are insufficient super-soft ({approx}0.1 keV) X-ray sources in either spiral or elliptical galaxies to account for the rate of explosion of Type Ia supernovae (SNe Ia) in either the single-degenerate or the double-degenerate scenarios. We quantify the amount of circumstellar matter that would be required to suppress the soft X-ray flux by yielding a column density in excess of 10{sup 23} cm{sup -2}. We summarize evidence that appropriate quantities of matter are extant in SNe Ia and in recurrent novae that may be supernova precursors. The obscuring matter is likely to have a large, but not complete, covering factor and to be substantially non-spherically symmetric. Assuming that much of the absorbed X-ray flux is re-radiated as blackbody radiation in the UV, we estimate that {approx}<100 sources might be detectable in the Galaxy Evolution Explorer All-sky Survey.

Wheeler, J. Craig [Department of Astronomy, University of Texas at Austin, Austin, TX (United States)] [Department of Astronomy, University of Texas at Austin, Austin, TX (United States); Pooley, D., E-mail: wheel@astro.as.utexas.edu [Department of Physics, Sam Houston State University, Huntsville, TX (United States)

2013-01-10T23:59:59.000Z

314

PT-symmetric sinusoidal optical lattices at the symmetry-breaking threshold  

SciTech Connect

The PT-symmetric potential V{sub 0}[cos(2{pi}x/a)+i{lambda}sin(2{pi}x/a)] has a completely real spectrum for {lambda}{<=}1 and begins to develop complex eigenvalues for {lambda}>1. At the symmetry-breaking threshold {lambda}=1 some of the eigenvectors become degenerate, giving rise to a Jordan-block structure for each degenerate eigenvector. In general this is expected to result in a secular growth in the amplitude of the wave. However, it has been shown in a recent paper by Longhi, by numerical simulation and by the use of perturbation theory, that for a broad initial wave packet this growth is suppressed, and instead a saturation leading to a constant maximum amplitude is observed. We revisit this problem by explicitly constructing the Bloch wave functions and the associated Jordan functions and using the method of stationary states to find the dependence on the longitudinal distance z for a variety of different initial wave packets. This allows us to show in detail how the saturation of the linear growth arises from the close connection between the contributions of the Jordan functions and those of the neighboring Bloch waves.

Graefe, Eva-Maria [Mathematics Department, Imperial College, London SW7 2BZ (United Kingdom); Jones, H. F. [Physics Department, Imperial College, London SW7 2BZ (United Kingdom)

2011-07-15T23:59:59.000Z

315

Compton scattering measurements from dense plasmas  

DOE Green Energy (OSTI)

Compton scattering has been developed for accurate measurements of densities and temperatures in dense plasmas. One future challenge is the application of this technique to characterize compressed matter on the National Ignition Facility where hydrogen and beryllium will approach extremely dense states of matter of up to 1000 g/cc. In this regime, the density, compressibility, and capsule fuel adiabat may be directly measured from the Compton scattered spectrum of a high-energy x-ray line source. Specifically, the scattered spectra directly reflect the electron velocity distribution. In non-degenerate plasmas, the width provides an accurate measure of the electron temperatures, while in partially Fermi degenerate systems that occur in laser-compressed matter it provides the Fermi energy and hence the electron density. Both of these regimes have been accessed in experiments at the Omega laser by employing isochorically heated solid-density beryllium and moderately compressed beryllium foil targets. In the latter experiment, compressions by a factor of 3 at pressures of 40 Mbar have been measured in excellent agreement with radiation hydrodynamic modeling.

Glenzer, S H; Neumayer, P; Doeppner, T; Landen, L; Lee, R W; Wallace, R; Weber, S; Lee, H J; Kritcher, A L; Falcone, R; Regan, S P; Sawada, H; Meyerhofer, D D; Gregori, G; Fortmann, C; Schwarz, V; Redmer, R

2007-10-02T23:59:59.000Z

316

Neutral Higgs Bosons in the Higgs Triplet Model with nontrivial mixing  

E-Print Network (OSTI)

We revisit the neutral Higgs sector of the Higgs Triplet Model, with non-negligible mixing in the CP-even Higgs sector. We examine the possibility that one of the Higgs boson state is the particle observed at the LHC at 125 GeV, and the other is either the small LEP excess at 98 GeV; or the CMS excess at 136 GeV; or that the neutral Higgs bosons are (almost) degenerate and have both mass 125 GeV. We show that, under general considerations, an (unmixed) neutral Higgs boson cannot have an enhanced decay branching ratio into gamma gamma with respect to the Standard Model one. An enhancement is however possible for the mixed case, but only for the heavier of the two neutral Higgs bosons, and not for mass-degenerate Higgs bosons. At the same time the branching ratios into WW^*,ZZ^*, bb and tau tau are similar to the Standard Model, or reduced. We correlate the branching ratios of both Higgs states into Z gamma to those into gamma gamma for the three scenarios. The mixed neutral sector of the Higgs triplet model exhibits some features which could distinguish it from other scenarios at the LHC.

Fatemeh Arbabifar; Sahar Bahrami; Mariana Frank

2012-11-29T23:59:59.000Z

317

Measurement of electronic splitting in PbS quantum dots by two-dimensional nonlinear spectroscopy  

Science Conference Proceedings (OSTI)

Quantum dots exhibit rich and complex electronic structure that makes them ideal for studying the basic physics of semiconductors in the intermediate regime between bulk materials and single atoms. The remarkable nonlinear optical properties of these nanostructures make them strong candidates for photonics applications. Here, we experimentally probe changes in the fine structure on ultrafast timescales of a colloidal solution of PbS quantum dots through their nonlinear optical response despite extensive inhomogeneous spectral broadening. Using continuum excitation and detection, we observe electronic coupling between nearly degenerate exciton states split by intervalley scattering at low exciton occupancy and a sub-100 fs frequency shift presumably due to phonon-assisted transitions. At high excitation intensities, we observe multi-exciton effects and sharp absorbance bands indicative of exciton-exciton coupling. Our experiments directly probe the nonlinear optical response of nearly degenerate quantum confined nanostructures with femtosecond temporal resolution despite extensive line broadening caused by the finite size distribution found in colloidal solutions.

Harel, E.; Rupich, S. M.; Schaller, R. D.; Talapin, D. V.; Engel, G. S. (Center for Nanoscale Materials); (Univ. of Chicago); (Northwestern Univ.)

2012-01-01T23:59:59.000Z

318

Hydrogen Outgassing from Lithium Hydride  

DOE Green Energy (OSTI)

Lithium hydride is a nuclear material with a great affinity for moisture. As a result of exposure to water vapor during machining, transportation, storage and assembly, a corrosion layer (oxide and/or hydroxide) always forms on the surface of lithium hydride resulting in the release of hydrogen gas. Thermodynamically, lithium hydride, lithium oxide and lithium hydroxide are all stable. However, lithium hydroxides formed near the lithium hydride substrate (interface hydroxide) and near the sample/vacuum interface (surface hydroxide) are much less thermally stable than their bulk counterpart. In a dry environment, the interface/surface hydroxides slowly degenerate over many years/decades at room temperature into lithium oxide, releasing water vapor and ultimately hydrogen gas through reaction of the water vapor with the lithium hydride substrate. This outgassing can potentially cause metal hydriding and/or compatibility issues elsewhere in the device. In this chapter, the morphology and the chemistry of the corrosion layer grown on lithium hydride (and in some cases, its isotopic cousin, lithium deuteride) as a result of exposure to moisture are investigated. The hydrogen outgassing processes associated with the formation and subsequent degeneration of this corrosion layer are described. Experimental techniques to measure the hydrogen outgassing kinetics from lithium hydride and methods employing the measured kinetics to predict hydrogen outgassing as a function of time and temperature are presented. Finally, practical procedures to mitigate the problem of hydrogen outgassing from lithium hydride are discussed.

Dinh, L N; Schildbach, M A; Smith, R A; Balazs1, B; McLean II, W

2006-04-20T23:59:59.000Z

319

Theoretical studies of high-order harmonic generation: Effects of symmetry, degeneracy, and orientation  

SciTech Connect

Using a quantum-mechanical three-step model, we present numerical calculations of the high-order harmonic generation from four polyatomic molecules. Ethylene (C{sub 2}H{sub 4}) serves as an example where orbital symmetry directly affects the harmonic yield. We treat the case of methane (CH{sub 4}) to address the high-order harmonic generation resulting from a molecule with degenerate orbitals. To this end we illustrate how the single-orbital contributions show up in the total high-order harmonic signal. This example illustrates the importance of adding coherently the amplitude contributions from the individual degenerate orbitals. Finally, we study the high-order harmonic generation from propane (C{sub 3}H{sub 8}) and butane (C{sub 4}H{sub 10}). These two molecules, being extended and far from spherical in structure, produce harmonics with nontrivial orientational dependencies. In particular, propane can be oriented so that very high-frequency harmonics are favored, and thus the molecule contains prospects for the generation of uv attosecond pulses.

Madsen, C. B.; Madsen, L. B. [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C (Denmark)

2007-10-15T23:59:59.000Z

320

QCD Thermodynamics with Three Flavors of Improved Staggered Quarks  

E-Print Network (OSTI)

We report on a study of QCD thermodynamics with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad O(a^2) improved staggered quark action. Simulations were carried out with lattice spacings 1/4T, 1/6T and 1/8T both for three degenerate quarks with masses less than or equal to the strange quark mass, m_s, and for degenerate up and down quarks with masses in the range 0.1 m_s \\leq m_{u,d} \\leq 0.6 m_s, and the strange quark mass fixed near its physical value. We present results for standard thermodynamics quantities, such as the Polyakov loop, the chiral order parameter and its susceptibility. For the quark masses studied to date we find a rapid crossover rather than a bona fide phase transition. We have carried out the first calculations of quark number susceptibilities with three flavors of sea quarks. These quantities are of physical interest because they are related to event-by-event fluctuations in heavy ion collision experiments. Comparison of susceptibilities at different lattice spacings show that our results are close to the continuum values.

The MILC Collaboration; C. Bernard; T. Burch; C. DeTar; Steven Gottlieb; E. B. Gregory; U. M. Heller; J. Osborn; R. Sugar; D. Toussaint

2004-05-27T23:59:59.000Z

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321

doi:10.1093/nar/gkr195 Regulation of the alternative splicing of tau exon 10 by SC35 and Dyrk1A  

E-Print Network (OSTI)

Abnormal alternative splicing of tau exon 10 results in imbalance of 3R-tau and 4R-tau expression, which is sufficient to cause neurofibrillary degeneration. Splicing factor SC35, a member of the superfamily of the serine/arginine-rich (SR) proteins, promotes tau exon 10 inclusion. The molecular mechanism by which SC35 participates in tau exon 10 splicing remains elusive. In the present study, we found that tau pre-mRNA was coprecipitated by SC35 tagged with HA. Mutation of the SC35-like exonic splicing enhancer located at exon 10 of tau affected both the binding of SC35 to tau pre-mRNA and promotion of tau exon 10 inclusion, suggesting that SC35 acts on the SC35-like exonic splicing enhancer to promote tau exon 10 inclusion. Dyrk1A (dual-specificity tyrosine-phosphorylated and regulated kinase 1A) phosphorylated SC35 in vitro and interacted with it in cultured cells. Overexpression of Dyrk1A suppressed SC350s ability to promote tau exon 10 inclusion. Downregulation of Dyrk1A promoted 4R-tau expression. Therefore, upregulation of Dyrk1A in Down syndrome brain or Alzheimers brain may cause dysregulation of tau exon 10 splicing through SC35, and probably together with other splicing factors, leading to the imbalance in 3R-tau and 4R-tau expression, which may initiate or accelerate tau pathology and cause neurofibrillary degeneration in the diseases.

Wei Qian; Hongwei Liang; Jianhua Shi; Nana Jin; Inge Grundke-iqbal; Khalid Iqbal; Cheng-xin Gong; Fei Liu

2010-01-01T23:59:59.000Z

322

Impact of energy filtering and carrier localization on the thermoelectric properties of granular semiconductors  

Science Conference Proceedings (OSTI)

Energy filtering has been widely considered as a suitable tool to increase the thermoelectric performances of several classes of materials. In its essence, energy filtering provides a way to increase the Seebeck coefficient by introducing a strongly energy-dependent scattering mechanism. Under certain conditions, however, potential barriers may lead to carrier localization, that may also affect the thermoelectric properties of a material. A model is proposed, actually showing that randomly distributed potential barriers (as those found, e.g., in polycrystalline films) may lead to the simultaneous occurrence of energy filtering and carrier localization. Localization is shown to cause a decrease of the actual carrier density that, along with the quantum tunneling of carriers, may result in an unexpected increase of the power factor with the doping level. The model is corroborated toward experimental data gathered by several authors on degenerate polycrystalline silicon and lead telluride. - Graphical abstract: In heavily doped semiconductors potential barriers may lead to both carrier energy filtering and localization. This may lead to an enhancement of the thermoelectric properties of the material, resulting in an unexpected increase of the power factor with the doping level. Highlights: Black-Right-Pointing-Pointer Potential barriers are shown to lead to carrier localization in thermoelectric materials. Black-Right-Pointing-Pointer Evidence is put forward of the formation of a mobility edge. Black-Right-Pointing-Pointer Energy filtering and localization may explain the enhancement of power factor in degenerate semiconductors.

Narducci, Dario, E-mail: dario.narducci@unimib.it [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy) [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Selezneva, Ekaterina [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy)] [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Cerofolini, Gianfranco [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy) [Department of Materials Science, University of Milano Bicocca, via Cozzi 53, 20125 Milano (Italy); Consorzio DeltaTi Research (Italy); Frabboni, Stefano; Ottaviani, Giampiero [Department of Physics, University of Modena and Reggio Emilia, via Campi 213, 41100 Modena (Italy)] [Department of Physics, University of Modena and Reggio Emilia, via Campi 213, 41100 Modena (Italy)

2012-09-15T23:59:59.000Z

323

Electricity Market Design and Price Manipulation  

E-Print Network (OSTI)

Integration of physical transactions and financial contracts is central to successful electricity market design. Virtually every energy transaction has some impact on prices. The mere fact that a physical transaction can affect prices to some degree, and thereby influence the prices of related financial contracts, cannot be a per se definition of price manipulation. A principled policy for characterizing price manipulation in organized electricity markets includes a stand-alone profitability test. Multiple market-clearing prices arise from degenerate pricing conditions that can occur in electricity markets under economic dispatch. In some instances, small changes in bilateral schedules can produce large changes in prices. These prices affect the value of associated financial transmission rights. A stand-alone profitability test distinguishes transactions that are consistent with workably competitive markets from transactions that serve no economic purpose other than to manipulate prices and profit from other financial contracts. Generalizing this standard to the degenerate conditions that give rise to multiple market-clearing prices provides a principled solution without undermining the market-design foundations that integrate economic dispatch, locational prices and financial transmission rights.

William W. Hogan; William W. Hogan I

2012-01-01T23:59:59.000Z

324

Repeat sequence chromosome specific nucleic acid probes and methods of preparing and using  

DOE Patents (OSTI)

A primer directed DNA amplification method to isolate efficiently chromosome-specific repeated DNA wherein degenerate oligonucleotide primers are used is disclosed. The probes produced are a heterogeneous mixture that can be used with blocking DNA as a chromosome-specific staining reagent, and/or the elements of the mixture can be screened for high specificity, size and/or high degree of repetition among other parameters. The degenerate primers are sets of primers that vary in sequence but are substantially complementary to highly repeated nucleic acid sequences, preferably clustered within the template DNA, for example, pericentromeric alpha satellite repeat sequences. The template DNA is preferably chromosome-specific. Exemplary primers and probes are disclosed. The probes of this invention can be used to determine the number of chromosomes of a specific type in metaphase spreads, in germ line and/or somatic cell interphase nuclei, micronuclei and/or in tissue sections. Also provided is a method to select arbitrarily repeat sequence probes that can be screened for chromosome-specificity. 18 figs.

Weier, H.U.G.; Gray, J.W.

1995-06-27T23:59:59.000Z

325

Structure of multiphoton quantum optics. I. Canonical formalism and homodyne squeezed states  

Science Conference Proceedings (OSTI)

We introduce a formalism of nonlinear canonical transformations for general systems of multiphoton quantum optics. For single-mode systems the transformations depend on a tunable free parameter, the homodyne local-oscillator angle; for n-mode systems they depend on n heterodyne mixing angles. The canonical formalism realizes nontrivial mixing of pairs of conjugate quadratures of the electromagnetic field in terms of homodyne variables for single-mode systems, and in terms of heterodyne variables for multimode systems. In the first instance the transformations yield nonquadratic model Hamiltonians of degenerate multiphoton processes and define a class of non-Gaussian, nonclassical multiphoton states that exhibit properties of coherence and squeezing. We show that such homodyne multiphoton squeezed states are generated by unitary operators with a nonlinear time evolution that realizes the homodyne mixing of a pair of conjugate quadratures. Tuning of the local-oscillator angle allows us to vary at will the statistical properties of such states. We discuss the relevance of the formalism for the study of degenerate (up-)down-conversion processes. In a companion paper [F. Dell'Anno, S. De Siena, and F. Illuminati, 69, 033813 (2004)], we provide the extension of the nonlinear canonical formalism to multimode systems, we introduce the associated heterodyne multiphoton squeezed states, and we discuss their possible experimental realization.

Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio [Dipartimento di Fisica 'E. R. Caianiello', Universita di Salerno, INFM UdR di Salerno, INFN Sezione di Napoli, Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi, SA (Italy)

2004-03-01T23:59:59.000Z

326

Photochemical Studies on Xanthurenic Acid  

NLE Websites -- All DOE Office Websites (Extended Search)

Photochemical Studies on Xanthurenic Acid Photochemical Studies on Xanthurenic Acid J. E. Roberts, J. F. Wishart, L. Martinez, C. F. Chignell Photochem.Photobiol. 72, 467-471 (2000) Abstract: The tryptophan metabolite xanthurenic acid has been isolated from aged human cataractous lenses. The photophysical properties of xanthurenic acid were examined to determine if it is a potential chromophore for age-related cataractogenesis. We found that xanthurenic acid produces singlet oxygen (F*= 0.17; CD3OD) with the same efficiency as the lenticular chromophore N-formyl kynurenine and quenches singlet oxygen at a rate similar to other tryptophan metabolites (2.1 x 107 M-1 s-1; CD3OD) found in the eye. As the mechanisms of induction of cataracts may also involve redox reactions, the interactions of hydrated electrons (e-aq), the azide radical

327

Dog Teeth and Hearing  

NLE Websites -- All DOE Office Websites (Extended Search)

Dog Teeth and Hearing Dog Teeth and Hearing Name: Chad Status: other Grade: 9-12 Location: Outside U.S. Country: Canada Date: Spring 2011 Question: Can a bad tooth problem, infection (we've had several teeth pulled) cause a problem with deafness in a dog ? We have a snoodle 14 years old, but still in other wise good health. Replies: Hi Chad, Sorry to hear about Snoodle's hearing and dental problems. Deafness in an older dog is not uncommon and it would not likely be due to any tooth related problems. A severe tooth infection that extends or penetrates through the bone into the ear canal would be very rare and you would see very obvious symptoms in the ear. If your vet has examined Snoodle and there were no obvious problems related to the ear canal, then I would attribute the hearing loss to an age related change. I hope this helps.

328

Weapons testing data determines brain makes new neurons into adulthood  

NLE Websites -- All DOE Office Websites (Extended Search)

4 4 For immediate release: 06/10/2013 | NR-13-06-04 Weapons testing data determines brain makes new neurons into adulthood Anne M Stark, LLNL, (925) 422-9799, stark8@llnl.gov Image courtesy of National Institutes of Health. LIVERMORE, Calif. -- Using data derived from nuclear weapons testing of the 1950s and '60s, Lawrence Livermore scientists have found that a small portion of the human brain involved in memory makes new neurons well into adulthood. The research may have profound impacts on human behavior and mental health. The study supports the importance of investigating the therapeutic potential of applying adult neurogenesis to the treatment of age-related cognitive disorders. Neurogenesis is the process by which neurons are generated from neural stem

329

Structural Basis of Pre-existing Immunity to the 2009 H1N1 Pandemic  

NLE Websites -- All DOE Office Websites (Extended Search)

Structural Basis of Pre-existing Immunity to the 2009 Structural Basis of Pre-existing Immunity to the 2009 H1N1 Pandemic Influenza Virus The emergence of the 2009 H1N1 influenza pandemic, also known as the "swine flu", marks the first human flu pandemic in 40 years and has caused significant human infection and mortality globally (1). The emergence of the 2009 H1N1 flu marks the first time that an influenza pandemic was triggered by a virus carrying the same hemagglutinin (HA) subtype as circulating seasonal strains. In contrast, all prior pandemics were caused by the rise of a novel influenza strain with a different hemagglutinin subtype. And unlike seasonal flu that usually affects the elderly most severely, swine flu has been primarily targeting people under the age of 65, implying some age-related pre-existing immunity (2, 3).

330

STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.  

Science Conference Proceedings (OSTI)

This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.

Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

2001-03-22T23:59:59.000Z

331

Safety research programs sponsored by Office of Nuclear Regulatory Research. Quarterly progress report, January 1-March 31, 1984. Volume 4, No. 1  

Science Conference Proceedings (OSTI)

The projects reported are the following: High Temperature Reactor Research, SSC Development, Validation and Application, CRBR Balance of Plant Modeling, Thermal-Hydraulic Reactor Safety Experiments, Development of Plant Analyzer, Code Assessment and Application (Transient and LOCA Analyses), Thermal Reactor Code Development (RAMONA-3B), Calculational Quality Assurance in Support of PTS; Stress Corrosion Cracking of PWR Steam Generator Tubing, Bolting Failure Analysis, Probability Based Load Combinations for Design of Category I Structures, Mechanical Piping Benchmark Problems, Identification of Age-Related Failure Modes; Analysis of Human Error Data for Nuclear Power Plant Safety-Related Events, Human Factors Aspects of Safety/Safeguards Interactions During Routine Reactor Operations and Off-Normal Conditions, Emergency Action Levels, and Protective Action Decision Making.

Bari, R.A.; Cerbone, R.J.; Czajkowski, C.J.; Ginsberg, T.; Greene, G.A.; Guppy, J.G.; Hall, R.E.; Luckas, W.J. Jr.; O'Brien, J.N.; Pratt, W.T.

1984-08-01T23:59:59.000Z

332

Aging in place: design issues for the elderly with a focus on retrofitting bathrooms  

E-Print Network (OSTI)

As the median age rises nationwide Americans are confronted with serious issues of housing and healthcare for the disabled and elderly in this century. In the midst of this problem are the disabled and older Americans with aging related serious chronic illnesses. Included are culturally diverse adults that have very limited incomes, and speak little or no English. Often they reside in small rundown hotel rooms, or in poorly accessible residences. Despite the need, few long-term care resources are available. This research finds that for many, independently aging in place is a preferred solution. For others, the solution to housing and healthcare falls to the family, or government. The architectural design guidelines of the Americans with Disabilities Act of 1990 (ADA)--that address mobility barriers--are a step in the right direction, but the ADA is only the beginning. Pressures of old age security continue.

Cruz, Elias Tony

1995-01-01T23:59:59.000Z

333

Research and Development Roadmaps for Nondestructive Evaluation of Cables, Concrete, Reactor Pressure Vessels, and Piping Fatigue  

SciTech Connect

The purpose of the Materials Aging and Degradation Pathway is to develop the scientific basis for understanding and predicting long-term environmental degradation behavior of materials in nuclear power plants and to provide data and methods to assess the performance of systems, structures, and components essential to safe and sustained nuclear power plant operations. The understanding of aging-related phenomena and their impacts on systems, structures, and components is expected to be a significant issue for any nuclear power plant planning for long-term operations (i.e., service beyond the initial license renewal period). Management of those phenomena and their impacts during long-term operations can be better enabled by improved methods and techniques for detection, monitoring, and prediction of systems, structures, and components degradation.

Clayton, Dwight A.; Bakhtiari, Sasan; Smith, Cyrus M.; Simmons, Kevin L.; Ramuhalli, Pradeep; Coble, Jamie B.; Brenchley, David L.; Meyer, Ryan M.

2013-04-16T23:59:59.000Z

334

Evaluation Of Automated Low-Field Nuclear Magnetic Resonance (NMR) Relaxometry For Analysis Of Silicone Polymers  

Science Conference Proceedings (OSTI)

Screening studies and Design of Experiments (DoE) were performed to evaluate measurement variation of a new, non-destructive Nuclear Magnetic Resonance (NMR) test system designed to assess age-induced degradation of Outer Pressure Pads (OPP). The test method and results from 54,275 measurements are described. A reduction in measurement error was obtained after metal support struts were replaced with plastic support struts adjacent to the front position of the test chamber. However, remaining interference and a lack of detecting any age-related degradation prevent the use of the NMR system as a non-destructive surveillance test for OPPs. A cursory evaluation of the system with cellular silicone samples obtained more uniform results with increased error as measurements approached the samples edge.

M. H. Wilson

2009-10-02T23:59:59.000Z

335

Technical Basis Document: A Statistical Basis for Interpreting Urinary Excretion of Plutonium Based on Accelerator Mass Spectrometry (AMS) for Selected Atoll Populations in the Marshall Islands  

Science Conference Proceedings (OSTI)

We have developed refined statistical and modeling techniques to assess low-level uptake and urinary excretion of plutonium from different population group in the northern Marshall Islands. Urinary excretion rates of plutonium from the resident population on Enewetak Atoll and from resettlement workers living on Rongelap Atoll range from fallout. Consequently, the age-related trends in urinary excretion of plutonium from Marshallese populations can be described by either a long-term component from residual systemic burdens acquired from previous exposures to worldwide fallout or a prompt (and eventual long-term) component acquired from low-level systemic intakes of plutonium associated with resettlement of the northern Marshall Islands, or some combination of both.

Bogen, K; Hamilton, T F; Brown, T A; Martinelli, R E; Marchetti, A A; Kehl, S R; Langston, R G

2007-05-01T23:59:59.000Z

336

A Procedure for Determination of Degradation Acceptance Criteria for Structures and Passive Components in Nuclear Power Plants  

Science Conference Proceedings (OSTI)

The Korea Atomic Energy Research Institute (KAERI) has been collaborating with Brookhaven National Laboratory since 2007 to develop a realistic seismic risk evaluation system which includes the consideration of aging of structures and components in nuclear power plants (NPPs). This collaboration program aims at providing technical support to a five-year KAERI research project, which includes three specific areas that are essential to seismic probabilistic risk assessment: (1) probabilistic seismic hazard analysis, (2) seismic fragility analysis including the effects of aging, and (3) a plant seismic risk analysis. The understanding and assessment of age-related degradations of structures, systems, and components and their impact on plant safety is the major goal of this KAERI-BNL collaboration. Four annual reports have been published before this report as a result of the collaboration research.

Nie, J.; Braverman, J.; Hofmayer, C.; Choun, Y-S.; Hahm, D.; Choi, I-K.

2012-01-30T23:59:59.000Z

337

Aging Management Guideline for commercial nuclear power plants: Battery chargers, inverters and uninterruptible power supplies. Final report  

SciTech Connect

This Aging Management Guideline (AMG) describes recommended methods for effective detection and mitigation of age-related degradation mechanisms in BWR and PWR commercial nuclear power plant battery chargers, inverters and uninterruptible power supplies important to license renewal. The intent of this AMG is to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner that allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already, experienced) and aging management program activities to the more generic results and recommendations presented herein.

Berg, R.; Stroinski, M.; Giachetti, R. [Multiple Dynamics Corp., Southfield, MI (United States)

1994-02-01T23:59:59.000Z

338

Aging management guideline for commercial nuclear power plants-stationary batteries. Final report  

Science Conference Proceedings (OSTI)

The Aging Management Guideline (AMG) describes recommended methods for effective detection and mitigation of age-related degradation mechanisms in BWR and PWR commercial nuclear power plant stationary batteries important to license renewal. The intent of this AMG is to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner that allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

Berg, R.; Shao, J.; Krencicki, G.; Giachetti, R. [Multiple Dynamics Corp., Southfield, MI (United States)

1994-03-01T23:59:59.000Z

339

Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Phase 1, Study  

Science Conference Proceedings (OSTI)

Pacific Northwest Laboratory evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume I, reviews diesel-generator experience to identify the systems and components most subject to aging degradation and isolates the major causes of failure that may affect future operational readiness. Evaluations show that as plants age, the percent of aging-related failures increases and failure modes change. A compilation is presented of recommended corrective actions for the failures identified. This study also includes a review of current, relevant industry programs, research, and standards. Volume II reports the results of an industry-wide workshop held on May 28 and 29, 1986 to discuss the technical issues associated with aging of nuclear service emergency diesel generators.

Hoopingarner, K.R.; Vause, J.W.; Dingee, D.A.; Nesbitt, J.F.

1987-08-01T23:59:59.000Z

340

Aging Management Guideline for commercial nuclear power plants: Motor control centers; Final report  

SciTech Connect

This Aging Management Guideline (AMG) provides recommended methods for effective detection and mitigation of age-related degradation mechanisms in Boiling Water Reactor (BWR) and Pressurized Water Reactor (PWR) commercial nuclear power plant motor control centers important to license renewal. The intent of this AMG is to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner that allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

Toman, G.; Gazdzinski, R.; O`Hearn, E. [Ogden Environmental and Energy Services Co., Inc., Blue Bell, PA (United States)

1994-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Aging management guideline for commercial nuclear power plants-pumps  

SciTech Connect

This Aging Management Guideline (AMG) describes recommended methods for effective detection and mitigation of age-related degradation mechanisms in BWR and PWR commercial nuclear power plant pumps important to license renewal. The intent of this AMG is to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner that allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

Booker, S.; Katz, D.; Daavettila, N.; Lehnert, D. [MDC-Ogden Environmental and Energy Services, Southfield, MI (United States)

1994-03-01T23:59:59.000Z

342

Low dose irradiation of the early vertebrate embryo and early onset of  

NLE Websites -- All DOE Office Websites (Extended Search)

irradiation of the early vertebrate embryo and early onset of irradiation of the early vertebrate embryo and early onset of tissue aging Lingling Ding Georgia Health Sciences University Abstract There is considerable overlap between cellular and molecular changes that occur in response to low doses of ionizing radiation and those that occur during aging. Both processes are characterized by accumulation of persistent DNA damage (“wear and tear” on the genome), persistent oxidative stress, and depletion of stem/progenitor cells, leading to loss of repair and regenerative capacity. Here we test a hypothesis that exposure to low-dose ionizing radiation accelerates normal, aging-related tissue changes. The work was performed using a small, genetically tractable vertebrate model organism, the Japanese medaka fish (Oryzias latipes). Medaka have a

343

Links between persistent DNA damage, genome instability, and aging  

NLE Websites -- All DOE Office Websites (Extended Search)

Links between persistent DNA damage, genome instability, and aging Links between persistent DNA damage, genome instability, and aging William Dynan Medical College of Georgia Abstract There is considerable overlap between cellular and molecular changes that occur in response to low doses of ionizing radiation and those that occur during aging. Both processes are characterized by accumulation of persistent DNA damage ("wear and tear" on the genome), accumulation of protein and lipid oxidation products, loss of regenerative capacity at the cellular and tissue level, and increased incidence of cancer. These observations support a hypothesis that exposure to low-dose ionizing radiation accelerates normal, aging-related tissue changes. We have investigated this hypothesis using a genetically tractable model organism, the Japanese medaka fish. The medaka is a whole-animal vertebrate

344

10 CFR 830 Major Modification Determination for Emergency Firewater Injection System Replacement  

SciTech Connect

The continued safe and reliable operation of the ATR is critical to the Department of Energy (DOE) Office of Nuclear Energy (NE) mission. While ATR is safely fulfilling current mission requirements, a variety of aging and obsolescence issues challenge ATR engineering and maintenance personnels capability to sustain ATR over the long term. First documented in a series of independent assessments, beginning with an OA Environmental Safety and Health Assessment conducted in 2003, the issues were validated in a detailed Material Condition Assessment (MCA) conducted as a part of the ATR Life Extension Program in 2007.Accordingly, near term replacement of aging and obsolescent original ATR equipment has become important to ensure ATR capability in support of NEs long term national missions. To that end, a mission needs statement has been prepared for a non-major system acquisition which is comprised of three interdependent sub-projects. The first project will replace the existent diesel-electrical bus (E-3), switchgear, and the fifty year old antiquated marine diesels with commercial power that is backed with safety-related emergency diesel generators (EDGs), switchgear, and uninterruptible power supply. The second project will replace the four, obsolete, original primary coolant pumps and motors. The third project, the subject of this major modification determination, will replace the current emergency firewater injection system (EFIS). The replacement water injection system will function as the primary emergency water injection system with the EFIS being retained as a defense-in-depth backup. Completion of this and the two other age-related projects (replacement of the ATR diesel bus (E-3) and switchgear and replacement of the existent aged primary coolant pumps and motors) will resolve major age-related operational issues plus make a significant contribution in sustaining the ATR safety and reliability profile. The major modification criteria evaluation of the project pre-conceptual design identified several issues that lead to the conclusion that the project is a major modification.

Noel Duckwitz

2011-05-01T23:59:59.000Z

345

BER2009.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

NERSC_BER'09 NERSC_BER'09 Large Scale Production Computing Requirements for Biological and Environmental Research Teresa Head-Gordon Lawrence Berkeley National Laboratory UC Berkeley NERSC_BER'09 Molecular Theory and Simulation Every attempt to employ mathematical methods in the study of (bio)chemical questions must be considered profoundly irrational and contrary to the spirit of (bio)chemistry. If mathematical analysis should ever hold a prominent place in (bio)chemistry - an aberration which is happily almost impossible - it would occasion a rapid and widespread degeneration of that science. A Comte (1830) NERSC_BER'09 Molecular Theory and Simulation Every attempt to employ mathematical methods in the study of (bio)chemical questions must be considered profoundly irrational and

346

 

NLE Websites -- All DOE Office Websites (Extended Search)

Type Ia Supernovae as Distance Indicators Type Ia Supernovae as Distance Indicators Brian Hayden ND/LBNL Abstract: Type Ia supernovae are remarkable for their use as distance indicators, yet a coherent physical explosion mechanism continues to elude us. In this talk, I will discuss my dissertation, which addresses many areas of contemporary SN Ia physics. I present a new light curve fitting technique, called "2-stretch", which demonstrates the diversity in SN Ia light curve shapes. 2-stretch also has implications when estimating the amount of nickel-56 produced in the explosion, which powers the light curve through radioactive decay. I will present a direct search for SN Ia companion stars. Using the SDSS-II dataset, I am able to constrain possible progenitor models in the single degenerate channel, where a type Ia

347

 

NLE Websites -- All DOE Office Websites (Extended Search)

one way to blow up a white dwarf one way to blow up a white dwarf Daniel Kasen LBNL/UCB Abstract: Despite intense observational and theoretical study, the progenitors of Type Ia supernovae remain uncertain. Recent observations are challenging the commonly held view that the exploding star always has a mass near the Chandrasekhar limit. I will review the different channels leading to the thermonuclear disruption of a carbon oxygen white dwarf, focusing on how these scenarios might be discriminated using observations of supernova spectra, light curves, and polarization. I will describe some theoretical predictions which may be useful in testing both the single degenerate and double white dwarf merger scenarios, and offer some model comparisons to recent observations of so-called "super-Chandrasekhar mass" events. I

348

A 3-D Link between Antibiotic Resistance and Brain Disease  

NLE Websites -- All DOE Office Websites (Extended Search)

A 3-D Link between Antibiotic Resistance and Brain Disease A 3-D Link between Antibiotic Resistance and Brain Disease The story of what makes certain types of bacteria resistant to a specific antibiotic has a sub-plot that gives insight into the cause of a rare form of brain degeneration among children, according to investigators at St. Jude Children's Research Hospital. The story takes a twist as key differences among the structures of its main molecular characters disappear and reappear as they are assembled in the cell. The story is based on a study of the three-dimensional (3-D) structure of an enzyme called pantothenate kinase, which triggers the first step in the production coenzyme A (CoA), a molecule that is indispensable to all forms of life. Enzymes are proteins that speed up biochemical reactions. CoA plays a pivotal role in the cells' ability to extract energy from fatty

349

Feeding  

NLE Websites -- All DOE Office Websites (Extended Search)

Feeding Feeding the Pipeline: The SNfactory Supernova Search Richard Scalzo NERSC User Group Meeting October 4, 2005 Outline Background ● Interest in supernova science ● Observational challenges in finding supernovae The SNfactory search pipeline ● Description of hardware ● Past searches and challenges in development ● Present and future Why supernovae are interesting Two types of SNe: "type Ia" and "core-collapse". SNe Ia ● Model: Thermonuclear explosion of degenerate star(s) (carbon-oxygen white dwarf + binary companion star) ● Characteristic Si II absorption line in spectrum ● Brightness very uniform → good distance indicators Other SNe (types Ib, Ic, II) ● Gravitational collapse of core of young, massive star ● Spectra are diverse; evidence of stellar envelope (H, He) ● Rate tracks star formation rate; may be GRB progenitors SNe

350

Electric and magnetic screenings of gluons in a model with dimension-2 gluon condensate  

E-Print Network (OSTI)

Electric and magnetic screenings of the thermal gluons are studied by using the background expansion method in a gluodynamic model with dimension-2 gluon condensate. At low temperature, the electric and magnetic gluons are degenerate. With the increasing of temperature, it is found that the electric and magnetic gluons start to split at certain temperature $T_0$. The electric screening mass changes rapidly with temperature when $T>T_0$, and the Polyakov loop expectation value rises sharply around $T_0$ from zero in the vacuum to a value around 0.8 at high temperature. This suggests that the color electric deconfinement phase transition is driven by electric gluons. It is also observed that the magnetic screening mass keeps almost the same as its vacuum value, which manifests that the magnetic gluons remains confined. Both the screening masses and the Polyakov loop results are qualitatively in agreement with the Lattice calculations.

Fukun Xu; Mei Huang

2011-11-22T23:59:59.000Z

351

Soluble Models of Strongly Interacting Ultracold Gas Mixtures in Tight Waveguides  

Science Conference Proceedings (OSTI)

A Fermi-Bose mapping method is used to determine the exact ground states of several models of mixtures of strongly interacting ultracold gases in tight waveguides, which are generalizations of the Tonks-Girardeau (TG) gas (1D Bose gas with point hard cores) and fermionic Tonks-Girardeau (FTG) gas (1D spin-aligned Fermi gas with infinitely strong zero-range attractions). We detail the case of a Bose-Fermi mixture with TG boson-boson (BB) and boson-fermion (BF) interactions. Exact results are given for density profiles in a harmonic trap, single-particle density matrices, momentum distibutions, and density-density correlations. Since the ground state is highly degenerate, we analyze the splitting of the ground manifold for large but finite BB and BF repulsions.

Girardeau, M. D. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Minguzzi, A. [Laboratoire de Physique et Modelisation des Mileux Condenses, C.N.R.S., B.P. 166, 38042 Grenoble (France)

2007-12-07T23:59:59.000Z

352

Phase structure of a generalized Nambu Jona-Lasinio model with Wilson fermions in the mean field or large $N$-expansion  

E-Print Network (OSTI)

We analyze the vacuum structure of a generalized lattice Nambu--Jona-Lasinio model with two flavors of Wilson fermions, such that its continuum action is the most general four-fermion action with 'trivial' color interactions, and having a $SU(2)_V x SU(2)_A$ symmetry in the chiral limit. The phase structure of this model in the space of the two four-fermion couplings shows, in addition to the standard Aoki phases, new phases with $ != 0$, in close analogy to similar results recently suggested by some of us for lattice QCD with two degenerate Wilson fermions. This result shows how the phase structure of an effective model for low energy QCD cannot be entirely understood from Wilson Chiral Perturbation Theory, based on the standard QCD chiral effective Lagrangian approach.

V. Azcoiti; G. Di Carlo; E. Follana; M. Giordano; A. Vaquero

2013-05-08T23:59:59.000Z

353

Emergent dimensional reduction of the spin sector in a model for narrow-band manganites  

SciTech Connect

The widely used double-exchange model for manganites is shown to support various striped phases at filling fractions 1/n (n = 3, 4, 5, . . .), in the previously unexplored regime of narrow bandwidth and small Jahn-Teller coupling. Working in two dimensions, our main result is that these stripes can be individually spin flipped without a physically relevant change in the energy, i.e., we find a large ground-state manifold with nearly degenerate energies. The two-dimensional spin system thus displays an unexpected dynamically generated dimensional reduction into decoupled one-dimensional stripes, even though the electronic states remain two dimensional. Relations of our results with recent literature addressing compass models in quantum computing are discussed.

Liang, Shuhua [ORNL; Daghofer, Maria [ORNL; Dong, Shuai [Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing; Sen, Cengiz [ORNL; Dagotto, Elbio R [ORNL

2011-01-01T23:59:59.000Z

354

 

NLE Websites -- All DOE Office Websites (Extended Search)

Exploding Supermassive White Dwarfs from the Nearby Supernova Factory Exploding Supermassive White Dwarfs from the Nearby Supernova Factory Richard Scalzo (Yale) Abstract: Type Ia supernova (SNe Ia) have become popular in recent years as luminosity distance indicators in cosmological experiments to study the dark energy; however, the progenitor systems, explosion mechanisms, and environments of these rare, luminous events are still poorly understood. Most SNe Ia are believed to result from the thermonuclear explosion of a single carbon-oxygen white dwarf, which accretes matter from a non-degenerate binary companion star until it reaches the Chandrasekhar limit (1.4 solar masses). I will present observations of an unusual SN Ia, 2007if, from the Nearby Supernova Factory, a wide-area SN Ia search and follow-up effort which ran from 2003 to 2008. The extreme brightness of

355

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Possible valence bond condensation in a frustrated cluster magnet Possible valence bond condensation in a frustrated cluster magnet Research at SNS's POWGEN instrument results in Nature Materials publication The work links magnetism on clusters to geometric magnetic frustration in extended solids, demonstrating a new paradigm for unparalleled chemical control and tunability in the search for collective, emergent electronic states of matter. A team from The Johns Hopkins University and led by Tyrel McQueen recently synthesized and characterized the geometrically frustrated magnetic system, LiZn2Mo3O8. In such systems, competing exchange interactions cannot all be satisfied and as a result, the ground state degenerates. The material appears to form a condensed valence bond state that is reminiscent of the long-sought resonating valence bond state and a possible

356

Low Dose Radiation Stimulates Antioxidant Capacity in the Brain and Lessens  

NLE Websites -- All DOE Office Websites (Extended Search)

Stimulates Antioxidant Capacity in the Brain and Lessens Stimulates Antioxidant Capacity in the Brain and Lessens Behavioral Symptoms in a 6-OHDA-Induced Rat Model of Parkinson's Disease Mohan Doss Fox Chase Cancer Center Abstract Background: Progressive degeneration of dopaminergic neurons in the substantia nigra (SN) pars compacta results in motor deficits in Parkinson’s disease (PD) patients. Oxidative damage to the nigral dopaminergic neurons has been implicated in the pathogenesis of Parkinson’s disease. Our hypothesis is that low dose radiation induces the production of antioxidants in the brain, which could provide protection to the dopaminergic neurons, potentially leading to prevention or stabilization of PD. The purpose of the study is (1) to determine the effect of low dose radiation on the total antioxidant capacity in SN in

357

Argonne CNM News: Shedding Light on Nature's Nanoscale Control of Solar  

NLE Websites -- All DOE Office Websites (Extended Search)

Shedding Light on Nature's Nanoscale Control of Solar Energy Shedding Light on Nature's Nanoscale Control of Solar Energy Scanning tunneling microscopy tips A schematic of the Rhodobacter sphaerodes hexameric core, featuring the "special pair" (P) of degenerate bacteriochlorophyll (BChl) molecules, and the active (a) and inactive (b) arms of BChl and bacteriopheophytin (BPh) molecules. The transient absorption (ΔA) spectra acquired following selective excitation of P are shown. Nature's process for storing solar energy occurs in light-absorbing protein complexes called photosynthetic reaction centers (RCs). Across billions of years of evolution, Nature has retained a common light-absorbing hexameric cofactor core for carrying out the very first chemical reaction of photosynthesis, the light-induced electron transfer across approximately 3

358

Two-photon spectroscopy of trapped HD$^+$ ions in the Lamb-Dicke regime  

E-Print Network (OSTI)

We study the feasibility of nearly-degenerate two-photon rovibrational spectroscopy in ensembles of trapped, sympathetically cooled hydrogen molecular ions using a resonance-enhanced multiphoton dissociation (REMPD) scheme. Taking advantage of quasi-coincidences in the rovibrational spectrum, the excitation lasers are tuned close to an intermediate level to resonantly enhance two-photon absorption. Realistic simulations of the REMPD signal are obtained using a four-level model that takes into account saturation effects, ion trajectories, laser frequency noise and redistribution of population by blackbody radiation. We show that the use of counterpropagating laser beams enables optical excitation in an effective Lamb-Dicke regime. Sub-Doppler lines having widths in the 100 Hz range can be observed with good signal-to-noise ratio for an optimal choice of laser detunings. Our results indicate the feasibility of molecular spectroscopy at the $10^{-14}$ accuracy level for improved tests of molecular QED, a new det...

Tran, Vu Quang; Douillet, Albane; Koelemeij, Jeroen C J; Hilico, Laurent

2013-01-01T23:59:59.000Z

359

Segregated Network Polymer-Carbon Nanotubes Composites For Thermoelectrics  

E-Print Network (OSTI)

Polymers are intrinsically poor thermal conductors, which are ideal for thermoelectrics, but low electrical conductivity and thermopower have excluded them as feasible candidates as thermoelectric materials in the past. However, recent progress in polymer technology, particularly nanomaterial-polymer composites, can bring them into degenerate semiconductor or metallic regimes by incorporating a small amount of conductive filler. I demonstrate that such polymer nanocomposites can be viable for light-weight and economical thermoelectrics by using a segregated network approach for the nanocomposite synthesis. The thermoelectric properties were further improved by a change of stabilizer and drying conditions. The thermoelectric properties of the segregated network nanocomposites were measured for carbon nanotubes and the thermoelectric figure of merit, ZT, was calculated at room temperature. The influence on thermoelectric properties from filler concentration, stabilizer materials and drying condition are also discussed.

Kim, Dasaroyong

2009-08-01T23:59:59.000Z

360

The Schwarzschild-de Sitter solution in five-dimensional general relativity briefly revisited  

E-Print Network (OSTI)

We briefly revisit the Schwarzschild-de Sitter solution in the context of five-dimensional general relativity. We obtain a class of five-dimensional solutions of Einstein vacuum field equations into which the four-dimensional Schwarzschild-de Sitter space can be locally and isometrically embedded. We show that this class of solutions is well-behaved in the limit of lambda approaching zero. Applying the same procedure to the de Sitter cosmological model in five dimensions we obtain a class of embedding spaces which are similarly well-behaved in this limit. These examples demonstrate that the presence of a non-zero cosmological constant does not in general impose a rigid relation between the (3+1) and (4+1)-dimensional spacetimes, with degenerate limiting behaviour.

J. B. Fonseca-Neto; C. Romero

2007-03-20T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Microstructures of short-carbon-fiber-reinforced SiC composites prepared by hot-pressing  

SciTech Connect

Microstructures of short-carbon-fiber-reinforced silicon carbide composites, prepared by hot-pressing with MgO-Al{sub 2}O{sub 3}-Y{sub 2}O{sub 3} as sintering additives, were investigated by means of X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy. The results showed that the composites could be densified at a relatively low temperature of 1800 deg. C via the liquid-phase-sintering mechanism. The amorphous interphase in the composites not only avoided the direct contact of the fibers with the matrix, but also improved the fiber/matrix bonding, so they could improve the densification of the composites and avoid the degeneration of the carbon fiber. The nano silicon carbide derived from polycarbosilane, could play a role of improving the relative density of the composites.

He Xiulan [Department of Material Science and Engineering, Harbin University of Science and Technology, Harbin 150040 (China); Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)], E-mail: hexiulan1973@yahoo.com.cn; Guo Yingkui [Department of Material Science and Engineering, Harbin University of Science and Technology, Harbin 150040 (China); Zhou Yu; Jia Dechang [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2008-12-15T23:59:59.000Z

362

Dispersion in a thermal plasma including arbitrary degeneracy and quantum recoil  

Science Conference Proceedings (OSTI)

The longitudinal response function for a thermal electron gas is calculated including two quantum effects exactly, degeneracy, and the quantum recoil. The Fermi-Dirac distribution is expanded in powers of a parameter that is small in the nondegenerate limit and the response function is evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum is performed in terms of polylogarithms in the long-wavelength and quasistatic limits, giving results that apply for arbitrary degeneracy. The results are applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the nondegenerate and completely degenerate limits, and generalizing them to arbitrary degeneracy.

Melrose, D. B. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Mushtaq, A. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Theoretical Plasma Physics Division, PINSTECH, Nilore, 44000 Islamabad (Pakistan)

2010-11-15T23:59:59.000Z

363

On the Dynamics of Non-Relativistic Flavor-Mixed Particles  

E-Print Network (OSTI)

Evolution of a system of interacting non-relativistic quantum flavor-mixed particles is considered both theoretically and numerically. It was shown that collisions of mixed particles not only scatter them elastically, but can also change their mass eigenstates thus affecting particles' flavor composition and kinetic energy. The mass eigenstate conversions and elastic scattering are related but different processes, hence the conversion cross-section can be arbitrarily large even when the elastic scattering cross-section vanishes. The conversions are efficient when the mass eigenstates are well-separated in space but suppressed if their wave-packets overlap; the suppression is most severe for mass-degenerate eigenstates in flat space-time. The mass eigenstate conversions can lead to an interesting process, called `quantum evaporation,' in which mixed particles, initially confined deep inside a gravitational potential well and scattering only off each other, can escape from it without extra energy supply leaving...

Medvedev, Mikhail V

2013-01-01T23:59:59.000Z

364

Goldstone-Mode Phonon Dynamics in the Pyrochlore Cd2Re2O7  

Science Conference Proceedings (OSTI)

We have measured the polarized Raman scattering spectra of Cd{sub 2}Re{sub 2}O{sub 7}, the first superconducting pyrochlore, as a function of temperature. For temperatures below the cubic-to-tetragonal structural phase transition (SPT) at 200 K, a peak with B{sub 1} symmetry develops at zero frequency with divergent intensity. We identify this peak as the first observation of the Goldstone phonon in a crystalline solid. The Goldstone phonon is a collective excitation that exists due to the breaking of the continuous symmetry with the SPT. Its emergence coincides with that of a Raman-active soft mode. The order parameter for both features derives from an unstable doubly degenerate vibration (with E{sub u} symmetry) of the O1 atoms which drives the SPT.

Kendziora, C. A. [Naval Research Laboratory, Washington, D.C.; Sergienko, I. A. [Memorial University of Newfoundland, St. John's Newfoundland, Canada; Jin, Rongying [ORNL; He, Jian [ORNL; Keppens, Veerle [ORNL; Sales, Brian C [ORNL; Mandrus, David [ORNL

2005-01-01T23:59:59.000Z

365

Metallic 'Ferroelectrity' in the Pyrochlore Cd2Re2O7  

Science Conference Proceedings (OSTI)

A class of materials known as 'ferroelectric metals' was discussed theoretically by Anderson and Blount in 1965, but to date no examples of this class have been reported. Here we present measurements of the elastic moduli of Cd{sub 2}Re{sub 2}O{sub 7} through the 200 K cubic-to-tetragonal phase transition. A Landau analysis of the moduli reveals that the transition is consistent with Cd{sub 2}Re{sub 2}O{sub 7} being classified as a 'ferroelectric metal' in the weaker sense described by Anderson and Blount (loss of a center of symmetry). First-principles calculations of the lattice instabilities indicate that the dominant lattice instability corresponds to a two-fold degenerate mode with Eu symmetry, and that motions of the O ions forming the O octahedra dominate the energetics of the transition.

Sergienko, I. A. [Memorial University of Newfoundland, St. John's Newfoundland, Canada; Keppens, Veerle [ORNL; McGuire, M. A. [University of Mississippi, The; Jin, Rongying [ORNL; He, Jian [ORNL; Curnoe, S. H. [Memorial University of Newfoundland, St. John's Newfoundland, Canada; Sales, Brian C [ORNL; Blaha, P. [Institute for Materials Chemistry, TU Vienna; Singh, David J [ORNL; Schwartz, K. [Institute for Materials Chemistry, TU Vienna; Mandrus, David [ORNL

2004-01-01T23:59:59.000Z

366

Entropy production for mechanically or chemically driven biomolecules  

E-Print Network (OSTI)

Entropy production along a single stochastic trajectory of a biomolecule is discussed for two different sources of non-equilibrium. For a molecule manipulated mechanically by an AFM or an optical tweezer, entropy production (or annihilation) occurs in the molecular conformation proper or in the surrounding medium. Within a Langevin dynamics, a unique identification of these two contributions is possible. The total entropy change obeys an integral fluctuation theorem and a class of further exact relations, which we prove for arbitrarily coupled slow degrees of freedom including hydrodynamic interactions. These theoretical results can therefore also be applied to driven colloidal systems. For transitions between different internal conformations of a biomolecule involving unbalanced chemical reactions, we provide a thermodynamically consistent formulation and identify again the two sources of entropy production, which obey similar exact relations. We clarify the particular role degenerate states have in such a description.

Tim Schmiedl; Thomas Speck; Udo Seifert

2006-01-27T23:59:59.000Z

367

Highly conductive p-type amorphous oxides from low-temperature solution processing  

Science Conference Proceedings (OSTI)

We report solution-processed, highly conductive (resistivity 1.3-3.8 m{Omega} cm), p-type amorphous A-B-O (A = Bi, Pb; B = Ru, Ir), processable at temperatures (down to 240 Degree-Sign C) that are compatible with plastic substrates. The film surfaces are smooth on the atomic scale. Bi-Ru-O was analyzed in detail. A small optical bandgap (0.2 eV) with a valence band maximum (VBM) below but very close to the Fermi level (binding energy E{sub VBM} = 0.04 eV) explains the high conductivity and suggests that they are degenerated semiconductors. The conductivity changes from three-dimensional to two-dimensional with decreasing temperature across 25 K.

Li Jinwang [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Tokumitsu, Eisuke [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259-R2-19 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Koyano, Mikio [Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Mitani, Tadaoki [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Shimoda, Tatsuya [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

2012-09-24T23:59:59.000Z

368

QCD at imaginary chemical potential with Wilson fermions  

E-Print Network (OSTI)

We investigate the phase diagram in the temperature, imaginary chemical potential plane for QCD with three degenerate quark flavors using Wilson type fermions. While more expensive than the staggered fermions used in past studies in this area, Wilson fermions can be used safely to simulate systems with three quark flavors. In this talk, we focus on the (pseudo)critical line that extends from $\\mu=0$ in the imaginary chemical potential plane, trace it to the Roberge-Weiss line, and determine its location relative to the Roberge-Weiss transition point. In order to smoothly follow the (pseudo)critical line in this plane we perform a multi-histogram reweighting in both temperature and chemical potential. To perform reweighting in the chemical potential we use the compression formula to compute the determinants exactly. Our results are compatible with the standard scenario.

Andrei Alexandru; Anyi Li

2013-12-04T23:59:59.000Z

369

Longitudinal electric conductivity and dielectric permeability in quantum plasma with constant collision frequency in Mermin' approach  

E-Print Network (OSTI)

Detailed deducing of formulas for longitudinal electric conductivity and dielectric permeability in the quantum degenerate collisional plasma with constant collision frequency in Mermin' approach is given. The kinetic Schr\\"{o}dinger-Boltzmann equation in momentum space in relaxation approximation is used. It is shown that when collision frequency of plasma particles tends to zero (plasma passes to collisionless one), the deduced formula for dielectric function passes to the known Lindhard' formula for collisionless plasmas. It is shown that the deduced formula for dielectric permeability coincides with known Mermin's formula. Graphic research of the real and imaginary parts of dielectric function is made. Graphic comparison of the real and imaginary parts of dielectric function for quantum and classical plasma also is made. The module of derivative dielectric function also has been investigated graphically.

A. V. Latyshev; A. A. Yushkanov

2012-12-26T23:59:59.000Z

370

Longitudinal electric conductivity and dielectric permeability in quantum plasma with variable frequency of collisions in Mermin' approach  

E-Print Network (OSTI)

Formulas for longitudinal electric conductivity and dielectric permeability in the quantum non-degenerate collisional plasma with the frequency of collisions depending on momentum in Mermin' approach are received. The kinetic equation in momentum space in relaxation approximation is used. It is shown that when Planck's constant tends to zero, the deduced formula passes to the corresponding formula for classical plasma. It is shown also that when frequency of collisions of particles of plasma tends to zero (plasma passes to collisionless one), the deduced formula passes to the known Lindhard' formula received for collisionless plasmas. It is shown, that when frequency of collisions is a constant, the deduced formula for dielectric permeability passes in known Mermin' formula.

A. V. Latyshev; A. A. Yushkanov

2012-12-22T23:59:59.000Z

371

Longitudinal electric conductivity and dielectric permeability in quantum plasma with constant collision frequency in Mermin' approach  

E-Print Network (OSTI)

Detailed deducing of formulas for longitudinal electric conductivity and dielectric permeability in the quantum degenerate collisional plasma with constant collision frequency in Mermin' approach is given. The kinetic Schr\\"{o}dinger-Boltzmann equation in momentum space in relaxation approximation is used. It is shown that when collision frequency of plasma particles tends to zero (plasma passes to collisionless one), the deduced formula for dielectric function passes to the known Lindhard' formula for collisionless plasmas. It is shown that the deduced formula for dielectric permeability coincides with known Mermin's formula. Graphic research of the real and imaginary parts of dielectric function is made. Graphic comparison of the real and imaginary parts of dielectric function for quantum and classical plasma also is made. The module of derivative dielectric function also has been investigated graphically.

Latyshev, A V

2013-01-01T23:59:59.000Z

372

Longitudinal electric conductivity and dielectric permeability in quantum plasma with variable frequency of collisions in Mermin' approach  

E-Print Network (OSTI)

Formulas for longitudinal electric conductivity and dielectric permeability in the quantum non-degenerate collisional plasma with the frequency of collisions depending on momentum in Mermin' approach are received. The kinetic equation in momentum space in relaxation approximation is used. It is shown that when Planck's constant tends to zero, the deduced formula passes to the corresponding formula for classical plasma. It is shown also that when frequency of collisions of particles of plasma tends to zero (plasma passes to collisionless one), the deduced formula passes to the known Lindhard' formula received for collisionless plasmas. It is shown, that when frequency of collisions is a constant, the deduced formula for dielectric permeability passes in known Mermin' formula.

Latyshev, A V

2012-01-01T23:59:59.000Z

373

GaN directional couplers for integrated quantum photonics  

SciTech Connect

Large cross-section GaN waveguides are proposed as a suitable architecture to achieve integrated quantum photonic circuits. Directional couplers with this geometry have been designed with aid of the beam propagation method and fabricated using inductively coupled plasma etching. Scanning electron microscopy inspection shows high quality facets for end coupling and a well defined gap between rib pairs in the coupling region. Optical characterization at 800 nm shows single-mode operation and coupling-length-dependent splitting ratios. Two photon interference of degenerate photon pairs has been observed in the directional coupler by measurement of the Hong-Ou-Mandel dip [C. K. Hong, et al., Phys. Rev. Lett. 59, 2044 (1987)] with 96% visibility.

Zhang Yanfeng; McKnight, Loyd; Watson, Ian M.; Gu, Erdan; Calvez, Stephane; Dawson, Martin D. [Institute of Photonics, SUPA, University of Strathclyde, Glasgow G4 0NW (United Kingdom); Engin, Erman; Cryan, Martin J.; Thompson, Mark G.; O'Brien, Jeremy L. [Centre for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB (United Kingdom)

2011-10-17T23:59:59.000Z

374

Fractional domain walls from on-site softening in dipolar bosons  

E-Print Network (OSTI)

We study dipolar bosons in a 1D optical lattice and identify a region in parameter space---strong coupling but relatively weak on-site repulsion---hosting a series of stable charge-density-wave (CDW) states whose low-energy excitations, built from "fractional domain walls," have remarkable similarities to those of non-Abelian fractional quantum Hall states. Here, a conventional domain wall between translated CDW's may be split by inserting strings of degenerate, but inequivalent, CDW states. Outside these insulating regions, we find numerous supersolids as well as a superfluid regime. The mentioned phases should be accessible experimentally and, in particular, the fractional domain walls can be created in the ground state using single-site addressing, i.e., by locally changing the chemical potential.

Emma Wikberg; Jonas Larson; Emil J. Bergholtz; Anders Karlhede

2011-09-15T23:59:59.000Z

375

Single-phase Flow in Composite Poro-elastic Media  

E-Print Network (OSTI)

. The mathematical formulation and analysis of the Barenblatt-Biot model of elastic deformation and laminar flow in a heterogeneous porous medium is discussed. This describes consolidation processes in a fluid-saturated double-diffusion model of fractured rock. The model includes various degenerate cases, such as incompressible constituents or totally fissured components, and it is extended to include boundary conditions arising from partially exposed pores. The quasi-static initial-boundary problem is shown to have a unique weak solution, and this solution is strong when the data are smoother. 1. Introduction Any model of fluid flow through a deformable solid matrix must account for the coupling between the mechanical behavior of the matrix and the fluid dynamics. For example, compression of the medium leads to increased pore pressure, if the compression is fast relative to the fluid flow rate. Conversely, an increase in pore pressure induces a dilation of the matrix in response to t...

R. E. Showalter; Bahareh Momken

2002-01-01T23:59:59.000Z

376

S-Denying of the Signature Conditions Expands General Relativitys Space  

E-Print Network (OSTI)

We apply the S-denying procedure to signature conditions in a four-dimensional pseudo-Riemannian space i. e. we change one (or even all) of the conditions to be partially true and partially false. We obtain five kinds of expanded space-time for General Relativity. Kind I permits the space-time to be in collapse. Kind II permits the space-time to change its own signature. Kind III has peculiarities, linked to the third signature condition. Kind IV permits regions where the metric fully degenerates: there may be non-quantum teleportation, and a home for virtual photons. Kind V is common for kinds I, II, III, and IV.

Dmitri Rabounski; Florentin Smarandache; Larissa Borissova

2006-01-01T23:59:59.000Z

377

Accurate estimates for magnetic bottles in connection with superconductivity  

E-Print Network (OSTI)

Motivated by the theory of superconductivity and more precisely by the problem of the onset of superconductivity in dimension two, many papers devoted to the analysis in a semi-classical regime of the lowest eigenvalue of the Schr\\"odinger operator with magnetic field have appeared recently. Here we would like to mention the works by Bernoff-Sternberg, Lu-Pan, Del Pino-Felmer-Sternberg and Helffer-Morame and also Bauman-Phillips-Tang for the case of a disc. In the present paper we settle one important part of this question completely by proving an asymptotic expansion to all orders for low-lying eigenvalues for generic domains. The word `generic' means in this context that the curvature of the boundary of the domain has a unique non-degenerate maximum.

S. Fournais; B. Helffer

2004-11-16T23:59:59.000Z

378

CERN LEP indications for two light Higgs bosons and the U(1){sup '} model  

SciTech Connect

Reanalyses of LEP data have shown preference to two light CP-even Higgs bosons. We discuss implications of such a Higgs boson spectrum for the minimal supersymmetric model extended by a standard model singlet chiral superfield and an additional Abelian gauge invariance [the U(1){sup '} model]. We, in particular, determine parameter regions that lead to two light CP-even Higgs bosons while satisfying existing bounds on the mass and mixings of the extra vector boson. In these parameter regions, the pseudoscalar Higgs is found to be nearly degenerate in mass with either the lightest or next-to-lightest Higgs boson. Certain parameters of the U(1){sup '} model such as the effective {mu} parameter are found to be significantly bounded by the LEP two light Higgs signal.

Demir, Durmus A. [Department of Physics, Izmir Institute of Technology, IZTECH, TR35430 (Turkey); Solmaz, Levent [Department of Physics, Izmir Institute of Technology, IZTECH, TR35430 (Turkey); Department of Physics, Balikesir University, Balikesir, TR10100 (Turkey); Solmaz, Saime [Department of Physics, Balikesir University, Balikesir, TR10100 (Turkey)

2006-01-01T23:59:59.000Z

379

Self-Calibration of BICEP1 Three-Year Data and Constraints on Astrophysical Polarization Rotation  

E-Print Network (OSTI)

Cosmic Microwave Background (CMB) polarimeters aspire to measure the faint $B$-mode signature predicted to arise from inflationary gravitational waves. They also have the potential to constrain cosmic birefringence which would produce non-zero expectation values for the CMB's $TB$ and $EB$ spectra. However, instrumental systematic effects can also cause these $TB$ and $EB$ correlations to be non-zero. In particular, an overall miscalibration of the polarization orientation of the detectors produces $TB$ and $EB$ spectra which are degenerate with isotropic cosmological birefringence, while also introducing a small but predictable bias on the $BB$ spectrum. The \\bicep three-year spectra, which use our standard calibration of detector polarization angles from a dielectric sheet, are consistent with a polarization rotation of $\\alpha = -2.77^\\circ \\pm 0.86^\\circ \\text{(statistical)} \\pm 1.3^\\circ \\text{(systematic)}$. We revise the estimate of systematic error on the polarization rotation angle from the two-year ...

Kaufman, J P; Shimon, M; Barkats, D; Bischoff, C; Buder, I; Keating, B G; Kovac, J M; Ade, P A R; Aikin, R; Battle, J O; Bierman, E M; Bock, J J; Chiang, H C; Dowell, C D; Duband, L; Filippini, J; Hivon, E F; Holzapfel, W L; Hristov, V V; Jones, W C; Kernasovskiy, S S; Kuo, C L; Leitch, E M; Mason, P V; Matsumura, T; Nguyen, H T; Ponthieu, N; Pryke, C; Richter, S; Rocha, G; Sheehy, C; Su, M; Takahashi, Y D; Tolan, J E; Yoon, K W

2013-01-01T23:59:59.000Z

380

Sisyphus Cooling of Lithium  

E-Print Network (OSTI)

Laser cooling to sub-Doppler temperatures by optical molasses is thought to be inhibited in atoms with unresolved, near-degenerate hyperfine structure in the excited state. We demonstrate that such cooling is possible in one to three dimensions, not only near the standard D2 line for laser cooling, but over a range extending to the D1 line. Via a combination of Sisyphus cooling followed by adiabatic expansion, we reach temperatures as low as 40 \\mu K, which corresponds to atomic velocities a factor of 2.6 above the limit imposed by a single photon recoil. Our method requires modest laser power at a frequency within reach of standard frequency locking methods. It is largely insensitive to laser power, polarization and detuning, magnetic fields, and initial hyperfine populations. Our results suggest that optical molasses should be possible with all alkali species.

Paul Hamilton; Geena Kim; Trinity Joshi; Biswaroop Mukherjee; Daniel Tiarks; Holger Mller

2013-08-08T23:59:59.000Z

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381

Spectral asymptotics via the semiclassical Birkhoff normal form  

E-Print Network (OSTI)

This article gives a simple treatment of the quantum Birkhoff normal form for semiclassical pseudo-differential operators with smooth coefficients. The normal form is applied to describe the discrete spectrum in a generalised non-degenerate potential well, yielding uniform estimates in the energy $E$. This permits a detailed study of the spectrum in various asymptotic regions of the parameters $(E,\\h)$, and gives improvements and new proofs for many of the results in the field. In the completely resonant case we show that the pseudo-differential operator can be reduced to a Toeplitz operator on a reduced symplectic orbifold. Using this quantum reduction, new spectral asymptotics concerning the fine structure of eigenvalue clusters are proved. In the case of polynomial differential operators, a combinatorial trace formula is obtained.

Laurent Charles; San Vu Ngoc

2006-05-03T23:59:59.000Z

382

Neutrino Unification  

E-Print Network (OSTI)

Present neutrino data are consistent with neutrino masses arising from a common seed at some ``neutrino unification'' scale $M_X$. Such a simple theoretical ansatz naturally leads to quasi-degenerate neutrinos that could lie in the electron-volt range with neutrino mass splittings induced by renormalization effects associated with supersymmetric thresholds. In such a scheme the leptonic analogue of the Cabibbo angle $\\theta_{\\odot}$ describing solar neutrino oscillations is nearly maximal. Its exact value is correlated with the smallness of $\\theta_{reactor}$. These features agree both with latest data on the solar neutrino spectra and with the reactor neutrino data. The two leading mass-eigenstate neutrinos present in \

P. H. Chankowski; A. Ioannisian; S. Pokorski; J. W. F Valle

2000-11-10T23:59:59.000Z

383

Two Component Dark Matters in S_4 x Z_2 Flavor Symmetric Extra U(1) Model  

E-Print Network (OSTI)

We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra U(1) model with S_4 x Z_2 flavor symmetry. In our model, the lightest flavon has very long lifetime of O(10^{18)) second which is longer than the age of the universe, but not long enough to explain the PAMELA result ~ O(10^{26}) sec. Such a situation could be avoidable by considering that the flavon is not the dominant component of dark matters and the dominant one is the lightest neutralino. With appropriate parameter set, density parameter of dark matter and over-abundance of positron flux in cosmic-ray are realized at the same time. There is interesting correlation between spectrum of positron flux and V_{MNS}. No excess of anti-proton in cosmic-ray suggests that sfermions are heavier than 4 TeV and the masses of the light Higgs bosons are degenerated.

Daikoku, Yasuhiro; Toma, Takashi

2011-01-01T23:59:59.000Z

384

Two Component Dark Matters in S_4 x Z_2 Flavor Symmetric Extra U(1) Model  

E-Print Network (OSTI)

We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra U(1) model with S_4 x Z_2 flavor symmetry. In our model, the lightest flavon has very long lifetime of O(10^{18)) second which is longer than the age of the universe, but not long enough to explain the PAMELA result ~ O(10^{26}) sec. Such a situation could be avoidable by considering that the flavon is not the dominant component of dark matters and the dominant one is the lightest neutralino. With appropriate parameter set, density parameter of dark matter and over-abundance of positron flux in cosmic-ray are realized at the same time. There is interesting correlation between spectrum of positron flux and V_{MNS}. No excess of anti-proton in cosmic-ray suggests that sfermions are heavier than 4 TeV and the masses of the light Higgs bosons are degenerated.

Yasuhiro Daikoku; Hiroshi Okada; Takashi Toma

2011-06-23T23:59:59.000Z

385

Soliton trains in Bose-Fermi mixtures  

E-Print Network (OSTI)

We theoretically consider the formation of bright solitons in a mixture of Bose and Fermi degenerate gases. While we assume the forces between atoms in a pure Bose component to be effectively repulsive, their character can be changed from repulsive to attractive in the presence of fermions provided the Bose and Fermi gases attract each other strongly enough. In such a regime the Bose component becomes a gas of effectively attractive atoms. Hence, generating bright solitons in the bosonic gas is possible. Indeed, after a sudden increase of the strength of attraction between bosons and fermions (realized by using a Feshbach resonance technique or by firm radial squeezing of both samples) soliton trains appear in the Bose-Fermi mixture.

T. Karpiuk; M. Brewczyk; S. Ospelkaus-Schwarzer; K. Bongs; M. Gajda; K. Rzazewski

2004-04-14T23:59:59.000Z

386

The Role of Conformal Symmetry in the Jackiw-Pi Model  

E-Print Network (OSTI)

The Jackiw-Pi model in 2+1 dimensions is a non-relativistic conformal field theory of charged particles with point-like self-interaction. For specific values of the interaction strengths the classical theory possesses vortex and multi-vortex solutions, which are all degenerate in energy. We compute the full set of first-order perturbative quantum corrections. Only the coupling constant g^2 requires renormalization; the fields and electric charge e are not renormalized. It is shown that in general the conformal symmetries are broken by an anomalous contribution to the conservation law, proportional to the beta-function. However, the beta-function vanishes upon restricting the coupling constants to values g^2 = +/- e^2, which includes the case in which vortex solutions exist. Therefore the existence of vortices also guarantees the preservation of the conformal symmetries.

M. O. de Kok; J. W. van Holten

2008-06-20T23:59:59.000Z

387

Orbital ice: An exact Coulomb phase on the diamond lattice  

SciTech Connect

We demonstrate the existence of an orbital Coulomb phase as the exact ground state of a p-orbital exchange Hamiltonian on the diamond lattice. The Coulomb phase is an emergent state characterized by algebraic dipolar correlations and a gauge structure resulting from local constraints (ice rules) of the underlying lattice models. For most ice models on the pyrochlore lattice, these local constraints are a direct consequence of minimizing the energy of each individual tetrahedron. On the contrary, the orbital ice rules are emergent phenomena resulting from the quantum orbital dynamics. We show that the orbital ice model exhibits an emergent geometrical frustration by mapping the degenerate quantum orbital ground states to the spin-ice states obeying the 2-in-2-out constraints on the pyrochlore lattice. We also discuss possible realization of the orbital ice model in optical lattices with p-band fermionic cold atoms.

Chern Giawei [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Wu Congjun [Department of Physics, University of California, San Diego, California 92093 (United States)

2011-12-15T23:59:59.000Z

388

Energy related applications of elementary particle physics. Final report  

DOE Green Energy (OSTI)

The current research position is summarized, and what could be done in the future to clarify issues which were opened up by the research is indicated. Following on the discussion of the viability of catalyzed fusion, there is presented along with the key experimental results, a short account of the physics surrounding the subject. This is followed by a discussion of key research topics addressed. In consequence of the progress made, it appears that the feasibility of a small-scale fusion based on catalyzed reactions rests on either the remote chance that a yet undiscovered ultraheavy negatively charged elementary particle exists in Nature, or on the possible technical realization of a system based on muon-catalyzed fusion (MuCF) in high-density degenerate hydrogen plasma (density 1000 LHD, temperature O(100 eV)). The lattter is considered to have practical promise.

Rafelski, J.

1991-08-31T23:59:59.000Z

389

Energy related applications of elementary particle physics  

DOE Green Energy (OSTI)

The current research position is summarized, and what could be done in the future to clarify issues which were opened up by the research is indicated. Following on the discussion of the viability of catalyzed fusion, there is presented along with the key experimental results, a short account of the physics surrounding the subject. This is followed by a discussion of key research topics addressed. In consequence of the progress made, it appears that the feasibility of a small-scale fusion based on catalyzed reactions rests on either the remote chance that a yet undiscovered ultraheavy negatively charged elementary particle exists in Nature, or on the possible technical realization of a system based on muon-catalyzed fusion (MuCF) in high-density degenerate hydrogen plasma (density 1000 LHD, temperature O(100 eV)). The lattter is considered to have practical promise.

Rafelski, J.

1991-08-31T23:59:59.000Z

390

The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice  

E-Print Network (OSTI)

The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling.

Philipp Gerhold; Karl Jansen; Jim Kallarackal

2011-11-21T23:59:59.000Z

391

Higgs boson mass bounds in the presence of a heavy fourth quark family  

E-Print Network (OSTI)

We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.

John Bulava; Philipp Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy

2013-01-16T23:59:59.000Z

392

Formation of singularities in solutions to the compressible radiation hydrodynamics equations with vacuum  

E-Print Network (OSTI)

We study the Cauchy problem for multi-dimensional compressible radiation hydrodynamics equations with vacuum. First, we present some sufficient conditions on the blow-up of smooth solutions in multi-dimensional space. Then, we obtain the invariance of the support of density for the smooth solutions with compactly supported initial mass density by the property of the system under the vacuum state. Based on the above-mentioned results, we prove that we cannot get a global classical solution, no matter how small the initial data are, as long as the initial mass density is of compact support. Finally, we will see that some of the results that we obtained are still valid for the isentropic flows with degenerate viscosity coefficients as well as 1-D case.

Yachun Li; Shengguo Zhu

2013-09-28T23:59:59.000Z

393

Interaction of a two-level atom with squeezed light  

E-Print Network (OSTI)

We consider a degenerate parametric oscillator whose cavity contains a two-level atom. Applying the Heisenberg and quantum Langevin equations, we calculate in the bad-cavity limit the mean photon number, the quadrature variance, and the power spectrum for the cavity mode in general and for the signal light and fluorescent light in particular. We also obtain the normalized second-order correlation function for the fluorescent light. We find that the presence of the two-level atom leads to a decrease in the degree of squeezing of the signal light. It so turns out that the fluorescent light is in a squeezed state and the power spectrum consists of a single peak only.

Eyob Alebachew; K. Fesseha

2006-10-16T23:59:59.000Z

394

Novel concept for pulse compression via structured spatial energy distribution  

E-Print Network (OSTI)

We present a novel concept for pulse compression scheme applicable at RF, microwave and possibly to optical frequencies based on structured energy distribution in cavities supporting degenerate band-edge (DBE) modes. For such modes a significant fraction of energy resides in a small fraction of the cavity length. Such energy concentration provides a basis for superior performance for applications in microwave pulse compression devices (MPC) when compared to conventional cavities. The novel design features: far larger loaded quality factor of the cavity and stored energy compared to conventional designs, energy feeding and extraction at the cavity center, substantial reduction of the cavity size by use of equivalent lumped circuits for low energy sections of the cavity, controlled pulse shaping via engineered extraction techniques. The presented concepts are general, in terms of equivalent transmission lines, and can be applied to a variety of realistic guiding structures.

Tamma, Venkata Ananth; Capolino, Filippo

2013-01-01T23:59:59.000Z

395

Well-posedness of compressible Euler equations in a physical vacuum  

E-Print Network (OSTI)

An important problem in gas and fluid dynamics is to understand the behavior of vacuum states, namely the behavior of the system in the presence of vacuum. In particular, physical vacuum, in which the boundary moves with a nontrivial finite normal acceleration, naturally arises in the study of the motion of gaseous stars or shallow water. Despite its importance, there are only few mathematical results available near vacuum. The main difficulty lies in the fact that the physical systems become degenerate along the vacuum boundary. In this paper, we establish the local-in-time well-posedness of three-dimensional compressible Euler equations for polytropic gases with physical vacuum by considering the problem as a free boundary problem.

Jang, Juhi

2010-01-01T23:59:59.000Z

396

Importance of non-parabolic band effects in the thermoelectric properties of semiconductors  

SciTech Connect

We present an analysis of the thermoelectric properties of of n-type GeTe and SnTe in relation to the lead chalcogenides PbTe and PbSe. We find that the singly degenerate conduction bands of semiconducting GeTe and SnTe are highly non-parabolic, even very close to the band edges. This leads to isoenergy surfaces with a strongly corrugated shape that is clearly evident at carrier concentrations well below 0.005 e per formula unit. Analysis within Boltzmann theory shows that this corrugation is favorable for the thermoelectric transport. As a result these materials may exhibit n-type performance exceeding that of the lead chalcogenides.

Singh, David J [ORNL] [ORNL; Parker, David S [ORNL] [ORNL; Chen, Xin [ORNL] [ORNL

2013-01-01T23:59:59.000Z

397

The Crystal Structure of TAL Effector PthXo1 Bound to Its DNA Target  

SciTech Connect

DNA recognition by TAL effectors is mediated by tandem repeats, each 33 to 35 residues in length, that specify nucleotides via unique repeat-variable diresidues (RVDs). The crystal structure of PthXo1 bound to its DNA target was determined by high-throughput computational structure prediction and validated by heavy-atom derivatization. Each repeat forms a left-handed, two-helix bundle that presents an RVD-containing loop to the DNA. The repeats self-associate to form a right-handed superhelix wrapped around the DNA major groove. The first RVD residue forms a stabilizing contact with the protein backbone, while the second makes a base-specific contact to the DNA sense strand. Two degenerate amino-terminal repeats also interact with the DNA. Containing several RVDs and noncanonical associations, the structure illustrates the basis of TAL effector-DNA recognition.

Mak, Amanda Nga-Sze; Bradley, Philip; Cernadas, Raul A.; Bogdanove, Adam J.; Stoddard, Barry L. (FHCRC); (Iowa State)

2012-02-10T23:59:59.000Z

398

The electronic structure of co-sputtered zinc indium tin oxide thin films  

SciTech Connect

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses {approx}50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO{sub 2} films.

Carreras, Paz; Antony, Aldrin; Bertomeu, Joan [Departament de Fisica Aplicada i Optica, Universitat de Barcelona, 08028 Barcelona (Spain); Gutmann, Sebastian [Department of Chemistry, University of South Florida, Tampa, Florida 33620 (United States); Schlaf, Rudy [Department of Electrical Engineering, University of South Florida, Tampa, Florida 33620 (United States)

2011-10-01T23:59:59.000Z

399

ORIGINAL PAPER Newly acquired Onchocerca volvulus filariae after doxycycline treatment  

E-Print Network (OSTI)

# The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Despite successful mass drug administration and vector control programs, the nematode Onchocerca volvulus is far from being eradicated. Therefore, new long-term sterilizing or macrofilaricidal drugs are needed. The depletion of Wolbachia endobacteria using doxycycline leads to long-term sterilizing effects and macrofilaricidal activity against female filariae of more than 60%. The worms die or degenerate 1827 months after doxycycline. However, during this time patients may be exposed to new infections. We evaluated these newly acquired worms in onchocercomas of doxycycline-treated patients in relation to transmission using morphology, histochemistry, and immunohistology. On an average, 10 % of the female filariae had been newly acquired per year in the treated groups. Our observations showed: (a) Sixty-three of 68 newly acquired worms harbored many intact Wolbachia, whereas none of the other surviving worms contained many

Sabine Specht; Achim Hoerauf; Ohene Adjei; Er Debrah; Dietrich W. Bttner; S. Specht; A. Hoerauf; O. Adjei; A. Debrah; O. Adjei; A. Debrah; D. W. Bttner

2009-01-01T23:59:59.000Z

400

Evidence for charge Kondo effect in superconducting Tl-doped PbTe  

SciTech Connect

We report results of low-temperature thermodynamic and transport measurements of Pb{sub 1-x}Tl{sub x}Te single crystals for Tl concentrations up to the solubility limit of approximately x = 1.5%. For all doped samples, we observe a low-temperature resistivity upturn that scales in magnitude with the Tl concentration. The temperature and field dependence of this upturn are consistent with a charge Kondo effect involving degenerate Tl valence states differing by two electrons, with a characteristic Kondo temperature T{sub K} {approx} 6 K. The observation of such an effect supports an electronic pairing mechanism for superconductivity in this material and may account for the anomalously high T{sub c} values.

Fisher, I

2010-01-11T23:59:59.000Z

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401

The SNO Solar Neutrino Data, Neutrinoless Double Beta-Decay and Neutrino Mass Spectrum  

E-Print Network (OSTI)

Assuming 3 neutrino mixing and massive Majorana neutrinos, we analyze the implications of the results of the solar neutrino experiments, including the latest SNO data, which favor the LMA MSW solution of the solar neutrino problem with \\tan^2 \\theta_sol | in neutrinoless double beta decay. For \\cos (2 \\theta_sol) \\geq 0.26, which follows from the analysis of the new solar neutrino data, we find significant lower limits on || in the cases of quasi-degenerate and inverted hierarchy neutrino mass spectrum, || \\geq 0.035 eV and || \\geq 8.5 10^-3 eV, respectively. If the spectrum is hierarchical the upper limit holds || \\leq 8.2 10^-3 eV. Correspondingly, not only a measured value of || \

S. Pascoli; S. T. Petcov

2002-05-02T23:59:59.000Z

402

Effects of a single fermion in a Bose Josephson junction  

SciTech Connect

We consider the tunneling properties of a single fermionic impurity immersed in a Bose-Einstein condensate in a double-well potential. For strong boson-fermion interaction, we show the existence of a tunnel resonance where a large number of bosons and the fermion tunnel simultaneously. We give analytical expressions for the line shape of the resonance using degenerate Brillouin-Wigner theory. We finally compute the time-dependent dynamics of the mixture. Using the fermionic tunnel resonances as a beam splitter for wave functions, we construct a Mach-Zehnder interferometer that allows complete population transfer from one well to the other by tilting the double-well potential and only taking into account the fermion's tunnel properties.

Rinck, M.; Bruder, C. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

2011-02-15T23:59:59.000Z

403

Electron and positron pair production of compact stars  

E-Print Network (OSTI)

Neutral stellar core at or over nuclear densities is described by a positive charged baryon core and negative charged electron fluid since they possess different masses and interactions. Based on a simplified model of a gravitationally collapsing or pulsating baryon core, we approximately integrate the Einstein-Maxwell equations and the equations for the number and energy-momentum conservation of complete degenerate electron fluid. We show possible electric processes that lead to the production of electron-positron pairs in the boundary of a baryon core and calculate the number and energy of electron-positron pairs. This can be relevant for understanding the energetic sources of supernovae and gamma-ray bursts.

Wen-Biao Han; Remo Ruffini; She-Sheng Xue

2011-10-04T23:59:59.000Z

404

H.H. Khenpo Jigme Phuntsho A Tribute and a Translation  

E-Print Network (OSTI)

Buddhas and the one singly heroic in destroying the misfortunes of degenerate age, along with his line of saints, bless Your Majesty. 134 s- o`N-e-bo'i-db/-'PN-dguN-ls-mTo; ;'bNs-i- e`-bo-rN-dbN-bde-dges-'o; ; kun-... -id--bdun-Xi-ONs-+n-'di-ni-Cos-l-oN-bn-Um-po'i-yN- 'dul-Xi-g/g-lg-KN-Cen-por-' ug-l-po-dN--'Kor-n-s-l-mjl-'d-ed-bs- Ng-dbN-o-Oos-m/Ns-med-i-yid-Nor-Sr-b-bZin-mKn-po-bsod-dr-s-is-yi-ge'i- gz/gs-s-p-dge-legs-'Pel; ;rb-uN-bc...

Phuntsho, Karma

2004-01-01T23:59:59.000Z

405

Form invariance and symmetry in the neutrino mass matrix  

SciTech Connect

We present the general form of the unitary matrices keeping invariant the Majorana neutrino mass matrix of specific texture suitable for explaining oscillation data. In the case of the tri-bimaximal pattern with two degenerate masses, we give a specific realization of the underlying U(1) symmetry which can be uplifted to a symmetry in a complete theory including charged leptons. For this, we present a model with three light SM-like Higgs doublets and one heavy Higgs triplet and find that one can accommodate the hierarchy of the charged-lepton masses. The lepton mass spectrum can also be achieved in another model extending the SM with three SM-singlet scalars transforming nontrivially under the flavor symmetry. We discuss how such a model has room for generating enough baryon asymmetry through leptogenesis in the framework of type-I and -II seesaw mechanisms.

Lashin, E. I. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh (Saudi Arabia); Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Nasri, S.; Malkawi, E. [Department of Physics, UAE University, P.O. Box 17551, Al-Ain (United Arab Emirates); Chamoun, N. [Physics Department, HIAST, P.O. Box 31983, Damascus (Syrian Arab Republic)

2011-01-01T23:59:59.000Z

406

Lorentz connection from a conformal gauge theory of Euclidean space  

E-Print Network (OSTI)

The quotient of the conformal group of Euclidean 4-space by its Weyl subgroup results in a geometry possessing many of the properties of relativistic phase space, including both a natural symplectic form and non-degenerate Killing metric. When we complete the identification with phase space by requiring the existence of orthogonal, canonically conjugate, metric submanifolds, we find that the induced metric and the spin connection are Lorentzian on the submanifolds, despite the Euclidean starting pont. By examining the structure equations of the biconformal space in an orthonormal frame adapted to its phase space properties, we also find that two new tensor fields emerge from this geometry. The first is a combination of the scale factor on the metric with the Weyl vector. The second comes from the components of the spin connection, symmetric with respect to the new metric. Though this field comes from the spin connection it transforms homogeneously.

Jeffrey S Hazboun; James T Wheeler

2013-05-29T23:59:59.000Z

407

Search for SUSY in the AMSB scenario with the DELPHI detector  

E-Print Network (OSTI)

The DELPHI experiment at the LEP e+e- collider collected almost 700 pb^-1 at centre-of-mass energies above the Z0 mass pole and up to 208 GeV. Those data were used to search for SUSY in the Anomaly Mediated SUSY Breaking (AMSB) scenario with a flavour independent common sfermion mass parameter. The searches covered several possible signatures experimentally accessible at LEP, with either the neutralino, the sneutrino or the stau being the Lightest Supersymmetric Particle (LSP). They included: the search for nearly mass-degenerate chargino and neutralino, which is a typical feature of AMSB; the search for Standard-Model-like or invisibly decaying Higgs boson; the search for stable staus; the search for cascade decays of SUSY particles resulting in the LSP and a low multiplicity final state containing neutrinos. No evidence of a signal was found, and thus constraints were set in the space of the parameters of the model.

The DELPHI Collaboration; J. Abdallah

2004-03-29T23:59:59.000Z

408

Scattering in the pion-nucleon negative parity channel in lattice QCD  

E-Print Network (OSTI)

We study the coupled pion-nucleon system (negative parity, isospin 1/2) based on a lattice QCD simulation for nf=2 mass degenerate light quarks. Both, standard 3-quarks baryon operators as well as meson-baryon (4+1)-quark operators are included. This is an exploratory study for just one lattice size and lattice spacing and at a pion mass of 266 MeV. Using the distillation method and variational analysis we determine energy levels of the lowest eigenstates. Comparison with the results of simple 3-quark correlation studies exhibits drastic differences and a new level appears. A clearer picture of the negative parity nucleon spectrum emerges. For the parameters of the simulation we may assume elastic s-wave scattering and can derive values of the phase shift.

C. B. Lang; V. Verduci

2012-12-20T23:59:59.000Z

409

Scattering in the pion-nucleon negative parity channel in lattice QCD  

E-Print Network (OSTI)

We study the coupled pion-nucleon system (negative parity, isospin 1/2) based on a lattice QCD simulation for nf=2 mass degenerate light quarks. Both, standard 3-quarks baryon operators as well as meson-baryon (4+1)-quark operators are included. This is an exploratory study for just one lattice size and lattice spacing and at a pion mass of 266 MeV. Using the distillation method and variational analysis we determine energy levels of the lowest eigenstates. Comparison with the results of simple 3-quark correlation studies exhibits drastic differences and a new level appears. A clearer picture of the negative parity nucleon spectrum emerges. For the parameters of the simulation we may assume elastic s-wave scattering and can derive values of the phase shift.

Lang, C B

2013-01-01T23:59:59.000Z

410

Mixtures of bosonic and fermionic atoms in optical lattices  

Science Conference Proceedings (OSTI)

We discuss the theory of mixtures of bosonic and fermionic atoms in periodic potentials at zero temperature. We derive a general Bose-Fermi Hubbard Hamiltonian in a one-dimensional optical lattice with a superimposed harmonic trapping potential. We study the conditions for linear stability of the mixture and derive a mean-field criterion for the onset of a bosonic superfluid transition. We investigate the ground-state properties of the mixture in the Gutzwiller formulation of mean-field theory, and present numerical studies of finite systems. The bosonic and fermionic density distributions and the onset of quantum phase transitions to demixing and to a bosonic Mott-insulator are studied as a function of the lattice potential strength. The existence is predicted of a disordered phase for mixtures loaded in very deep lattices. Such a disordered phase possessing many degenerate or quasidegenerate ground states is related to a breaking of the mirror symmetry in the lattice.

Albus, Alexander [Institut fuer Physik, Universitaet Potsdam, Am Neuen Palais 10, D-14469 Potsdam, (Germany); Dipartimento di Fisica, Universita di Salerno, Via S. Allende, I-84081 Baronissi (Saudi Arabia), Italy and Istituto Nazionale per la Fisica della Materia, I-84081 Baronissi (SA), (Italy); Illuminati, Fabrizio [Dipartimento di Fisica, Universita di Salerno, Via S. Allende, I-84081 Baronissi (Saudi Arabia), Italy and Istituto Nazionale per la Fisica della Materia, I-84081 Baronissi (SA), (Italy); Eisert, Jens [Institut fuer Physik, Universitaet Potsdam, Am Neuen Palais 10, D-14469 Potsdam, (Germany); Blackett Laboratory, Imperial College London, Prince Consort Road, SW7 2BW London, (United Kingdom)

2003-08-01T23:59:59.000Z

411

Spatial correlation of photon pairs produced in spontaneous parametric down-conversion  

SciTech Connect

We report the observation of spatial biphoton correlation in spontaneous parametric down conversion. The optical bench includes a type-I BBO crystal of effective length 2 mm, pumped by a 100 mW violet laser diode centered at 405.38 nm. Photon pairs are created with degenerate wavelength {approx_equal}810.76 nm. Once the horizontal counting rates have been measured, a simple geometrical recipe is shown to be useful in calculating bounds for the width of vertical counting rates. The spatial correlation between idler and signal photons is illustrated with a coincidence distribution of the coordinate pair (x{sub s},x{sub i}), with x{sub i,s} the idler (signal) detector position in horizontal scan.

Procopio, L. M. [Departamento de Fisica, Cinvestav, A.P. 14-740, Mexico D.F. 07000 (Mexico); Rosas-Ortiz, O. [Departamento de Fisica, Cinvestav, A.P. 14-740, Mexico D.F. 07000 (Mexico); Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, Mexico D.F. 01000 (Mexico); Velazquez, V. [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, A.P. 20-364, Mexico D.F. 04510 (Mexico)

2010-10-11T23:59:59.000Z

412

Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source  

Science Conference Proceedings (OSTI)

We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.

Corona, Maria [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico); Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2732, BC 22860 Ensenada (Mexico); Garay-Palmett, Karina; U'Ren, Alfred B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico)

2011-09-15T23:59:59.000Z

413

Variation of fundamental constants  

E-Print Network (OSTI)

We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.

V. V. Flambaum

2006-08-25T23:59:59.000Z

414

A Unified Theory of Quasibound States  

E-Print Network (OSTI)

We have developed a formalism that includes both quasibound states with real energies and quantum resonances within the same theoretical framework, and that admits a clean and unambiguous distinction between these states and the states of the embedding continuum. States described broadly as 'quasibound' are defined as having a connectedness (in the mathematical sense) to true bound states through the growth of some parameter. The approach taken here builds on our earlier work by clarifying several crucial points and extending the formalism to encompass a variety of continuous spectra, including those with degenerate energy levels. The result is a comprehensive framework for the study of quasibound states. The theory is illustrated by examining several cases pertinent to applications widely discussed in the literature.

Curt A. Moyer

2013-06-27T23:59:59.000Z

415

A METAL-RICH LOW-GRAVITY COMPANION TO A MASSIVE MILLISECOND PULSAR  

SciTech Connect

Most millisecond pulsars with low-mass companions are in systems with either helium-core white dwarfs or non-degenerate (''black widow'' or ''redback'') stars. A candidate counterpart to PSR J1816+4510 was identified by Kaplan et al. whose properties were suggestive of both types of companions although identical to neither. We have assembled optical spectroscopy of the candidate companion and confirm that it is part of the binary system with a radial velocity amplitude of 343 {+-} 7 km s{sup -1}, implying a high pulsar mass, M{sub psr}sin {sup 3} i = 1.84 {+-} 0.11 M{sub Sun }, and a companion mass M{sub c} sin {sup 3} i = 0.193 {+-} 0.012 M{sub Sun }, where i is the inclination of the orbit. The companion appears similar to proto-white dwarfs/sdB stars, with a gravity log{sub 10}(g) = 4.9 {+-} 0.3, and effective temperature 16, 000 {+-} 500 K. The strongest lines in the spectrum are from hydrogen, but numerous lines from helium, calcium, silicon, and magnesium are present as well, with implied abundances of roughly 10 times solar (relative to hydrogen). As such, while from the spectrum the companion to PSR J1816+4510 is superficially most similar to a low-mass white dwarf, it has much lower gravity, is substantially larger, and shows substantial metals. Furthermore, it is able to produce ionized gas eclipses, which had previously been seen only for low-mass, non-degenerate companions in redback or black widow systems. We discuss the companion in relation to other sources, but find that we understand neither its nature nor its origins. Thus, the system is interesting for understanding unusual stellar products of binary evolution, as well as, independent of its nature, for determining neutron-star masses.

Kaplan, D. L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee WI 53211 (United States); Bhalerao, V. B. [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India); Van Kerkwijk, M. H. [Department of Astronomy and Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Koester, D. [Institut fuer Theoretische Physik und Astrophysik, University of Kiel, D-24098 Kiel (Germany); Kulkarni, S. R. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Stovall, K., E-mail: kaplan@uwm.edu, E-mail: mhvk@astro.utoronto.ca [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249 (United States)

2013-03-10T23:59:59.000Z

416

Neutrino Mixings and Leptonic CP Violation from CKM Matrix and Majorana Phases  

E-Print Network (OSTI)

The high scale mixing unification hypothesis recently proposed by three of us (R. N. M., M. K. P. and G. R.) states that if at the seesaw scale, the quark and lepton mixing matrices are equal then for quasi-degenerate neutrinos, radiative corrections can lead to large solar and atmospheric mixings and small reactor angle at the weak scale in agreement with data. Evidence for quasi-degenerate neutrinos could, within this framework, be interpreted as a sign of quark-lepton unification at high scale. In the current work, we extend this model to show that the hypothesis works quite successfully in the presence of CP violating phases (which were set to zero in the first paper). In the case where the PMNS matrix is identical to the CKM matrix at the seesaw scale, with a Dirac phase but no Majorana phase, the low energy Dirac phase is predicted to be ($\\simeq 0.3^{\\circ}$) and leptonic CP-violation parameter $J_{CP} \\simeq (4 - 8)\\times 10^{-5}$ and $\\theta_{13} = 3.5^{\\circ}$. If on the other hand, the PMNS matrix is assumed to also have Majorana phases initially, the resulting theory damps radiative magnification phenomenon for a large range of parameters but nevertheless has enough parameter space to give the two necessary large neutrino mixing angles. In this case, one has $\\theta_{13} = 3.5^{\\circ} - 10^{\\circ}$ and $|J_{CP}|$ as large as $0.02-0.04$ which are accessible to long baseline neutrino oscillation experiments.

S. K. Agarwalla; M. K. Parida; R. N. Mohapatra; G. Rajasekaran

2006-11-16T23:59:59.000Z

417

Quantum mechanical and information theoretic view on classical glass transitions  

E-Print Network (OSTI)

Using the mapping of the Fokker-Planck description of classical stochastic dynamics onto a quantum Hamiltonian, we argue that a dynamical glass transition in the former must have a precise definition in terms of a quantum phase transition in the latter. At the dynamical level, the transition corresponds to a collapse of the excitation spectrum at a critical point. At the static level, the transition affects the ground state wavefunction: while in some cases it could be picked up by the expectation value of a local operator, in others the order may be non-local, and impossible to be determined with any local probe. Here we propose instead to use concepts from quantum information theory that are not centered around local order parameters, such as fidelity and entanglement measures. We show that for systems derived from the mapping of classical stochastic dynamics, singularities in the fidelity susceptibility translate directly into singularities in the heat capacity of the classical system. In classical glassy systems with an extensive number of metastable states, we find that the prefactor of the area law term in the entanglement entropy jumps across the transition. We also discuss how entanglement measures can be used to detect a growing correlation length that diverges at the transition. Finally, we illustrate how static order can be hidden in systems with a macroscopically large number of degenerate equilibrium states by constructing a three dimensional lattice gauge model with only short-range interactions but with a finite temperature continuous phase transition into a massively degenerate phase.

Claudio Castelnovo; Claudio Chamon; David Sherrington

2010-03-19T23:59:59.000Z

418

Isolation and characterization of resistance gene analogs (RGAs) in sorghum  

E-Print Network (OSTI)

The largest group of plant disease resistance (R) genes that share similar structures contains a predicted nucleotide-binding site (NBS) domain. NBS domains of this class of R genes show highly conserved amino acid motifs, which makes it possible to isolate resistance gene analogs (RGAs) by PCR with degenerate primers and homology searches from public databases. Multiple combinations of degenerate primers were designed from three conserved motifs (one motif was used for a subgroup-specific primer design) in the NBS regions of R genes of various plants. All combinations of primer pairs were used to amplify genomic DNA from sorghum. TIR-specific primer combinations showed no PCR amplification in sorghum. Homology searches identified many NBS-encoding sequences among the expressed or genomic molecular database entries for sorghum. Motif analysis of the sorghum NBS sequences that were identified in this study revealed eight major conserved motifs plus two additional highly conserved motifs, but no TIR-specific motifs. Phylogenetic analysis of sorghum NBS sequences showed tree topology typical of NBS-LRR genes, including clustered nodes and longbranch lengths. Eleven distinct families of NBS sequences, representing a highly diverse sample, were isolated from Sorghum bicolor. With two exceptions, sorghum RGA families appeared to be closely related in sequence to at least one R-gene cloned from other species. In addition, deduced amino acid sequences of sorghum RGAs showed strong sequence similarity to almost all known non-TIR (Toll/Interleukin 1 Receptor)- type R-genes. Mapping with sorghum RGA markers revealed one linkage group containing four out of ten randomly selected markers, suggesting non-random distribution of NBS sequences in the sorghum genome. Rice sequences homologous to sorghum NBS sequences were found from two-way BLAST searches. Some of them were shown to be orthologs, when determined by using phylogenetic approaches which combined five different evolution models and tree-building methods.

Cho, Jae-Min

2005-05-01T23:59:59.000Z

419

10 CFR 830 Major Modification Determination for the ATR Diesel Bus (E-3) and Switchgear Replacement  

SciTech Connect

Near term replacement of aging and obsolescent original ATR equipment has become important to ensure ATR capability in support of NEs long term national missions. To that end, a mission needs statement has been prepared for a non-major system acquisition which is comprised of three interdependent subprojects. The first project, subject of this determination, will replace the existent diesel-electrical bus (E-3) and associated switchgear. More specifically, INL proposes transitioning ATR to 100% commercial power with appropriate emergency backup to include: Provide commercial power as the normal source of power to the ATR loads currently supplied by diesel-electric power. Provide backup power to the critical ATR loads in the event of a loss of commercial power. Replace obsolescent critical ATR power distribution equipment, e.g., switchgear, transformers, motor control centers, distribution panels. Completion of this and two other age-related projects (primary coolant pump and motor replacement and emergency firewater injection system replacement) will resolve major age related operational issues plus make a significant contribution in sustaining the ATR safety and reliability profile. The major modification criteria evaluation of the project pre-conceptual design identified several issues make the project a major modification: 1. Evaluation Criteria #2 (Footprint change). The addition of a new PC-4 structure to the ATR Facility to house safety-related SSCs requires careful attention to maintaining adherence to applicable engineering and nuclear safety design criteria (e.g., structural qualification, fire suppression) to ensure no adverse impacts to the safety-related functions of the housed equipment. 2. Evaluation Criteria #3 (Change of existing process). The change to the strategy for providing continuous reliable power to the safety-related emergency coolant pumps requires careful attention and analysis to ensure it meets a project primary object to maintain or reduce CDF and does not negatively affect the efficacy of the currently approved strategy. 3. Evaluation Criteria #5 (Create the need for new or revised safety SSCs). The change to the strategy for providing continuous reliable power to the safety-related emergency coolant pumps, based on the pre-conceptual design, will require the addition of two quick start diesel generators, their associated power coordination/distribution controls, and a UPS to the list of safety-related SSCs. Similarly to item 1 above, the addition of these active SSCs to the list of safety-related SSCs and replacement of the E-3 bus requires careful attention to maintaining adherence to applicable engineering and nuclear safety design criteria (e.g., seismic qualification, isolation of redundant trains from common fault failures) to ensure no adverse impacts to the safety-related functions.

Noel Duckwtiz

2011-05-01T23:59:59.000Z

420

Black carbon snow albedo reduction  

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Black carbon snow albedo reduction Black carbon snow albedo reduction Title Black carbon snow albedo reduction Publication Type Journal Article Year of Publication 2012 Authors Hadley, Odelle L., and Thomas W. Kirchstetter Journal Nature Climate Change Volume 2 Pagination 437-440 Abstract Climate models indicate that the reduction of surface albedo caused by black-carbon contamination of snow contributes to global warming and near-worldwide melting of ice1, 2. In this study, we generated and characterized pure and black-carbon-laden snow in the laboratory and verified that black-carbon contamination appreciably reduces snow albedo at levels that have been found in natural settings1, 3, 4. Increasing the size of snow grains in our experiments decreased snow albedo and amplified the radiative perturbation of black carbon, which justifies the aging-related positive feedbacks that are included in climate models. Moreover, our data provide an extensive verification of the Snow, Ice and Aerosol Radiation model1, which will be included in the next assessment of the Intergovernmental Panel on Climate Change5.

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421

Overview of the US Department of Energy Light Water Reactor Sustainability Program  

Science Conference Proceedings (OSTI)

The US Department of Energy Light Water Reactor Sustainability Program is focused on the long-term operation of US commercial power plants. It encompasses two facets of long-term operation: (1) manage the aging of plant systems, structures, and components so that nuclear power plant lifetimes can be extended and the plants can continue to operate safely, efficiently, and economically; and (2) provide science-based solutions to the nuclear industry that support implementation of performance improvement technologies. An important aspect of the Light Water Reactor Sustainability Program is partnering with industry and the Nuclear Regulatory Commission to support and conduct the long-term research needed to inform major component refurbishment and replacement strategies, performance enhancements, plant license extensions, and age-related regulatory oversight decisions. The Department of Energy research, development, and demonstration role focuses on aging phenomena and issues that require long-term research and/or unique Department of Energy laboratory expertise and facilities and are applicable to all operating reactors. This paper gives an overview of the Department of Energy Light Water Reactor Sustainability Program, including vision, goals, and major deliverables.

K. A. McCarthy; D. L. Williams; R. Reister

2012-05-01T23:59:59.000Z

422

WRN Exonuclease Structure, Molecular Mechanism, and DNA EndProcessing Role  

Science Conference Proceedings (OSTI)

WRN is unique among the five human RecQ DNA helicases by having a functional exonuclease domain (WRN-exo) and being defective in the premature aging and cancer-related disorder Werner syndrome. Here, we characterize WRN-exo crystal structures, biochemical activity and participation in DNA end-joining. Metal ion complex structures, active site mutations and activity assays reveal a two-metal-ion mediated nuclease mechanism. The DNA end-binding Ku70/80 complex specifically stimulates WRN-exo activity, and structure-based mutational inactivation of WRN-exo alters DNA end-joining in human cells. We furthermore establish structural and biochemical similarities of WRN-exo to DnaQ family replicative proofreading exonucleases, with WRN-specific adaptations consistent with dsDNA specificity and functionally important conformational changes. These results indicate WRN-exo is a human DnaQ family member and support analogous proof-reading activities that are stimulated by Ku70/80 with implications for WRN functions in age related pathologies and maintenance of genomic integrity.

Perry, J. Jefferson P.; Yannone, Steven M.; Holden, Lauren G.; Hitomi, Chiharu; Asaithamby, Aroumougame; Han, Seungil; Cooper, PriscillaK.; Chen, David J.; Tainer, John A.

2006-02-15T23:59:59.000Z

423

An Investigation of Digital Instrumentation and Control System Failure Modes  

SciTech Connect

A study sponsored by the Nuclear Regulatory Commission study was conducted to investigate digital instrumentation and control (DI&C) systems and module-level failure modes using a number of databases both in the nuclear and non-nuclear industries. The objectives of the study were to obtain relevant operational experience data to identify generic DI&C system failure modes and failure mechanisms, and to obtain generic insights, with the intent of using results to establish a unified framework for categorizing failure modes and mechanisms. Of the seven databases studied, the Equipment Performance Information Exchange database was found to contain the most useful data relevant to the study. Even so, the general lack of quality relative to the objectives of the study did not allow the development of a unified framework for failure modes and mechanisms of nuclear I&C systems. However, an attempt was made to characterize all the failure modes observed (i.e., without regard to the type of I&C equipment under consideration) into common categories. It was found that all the failure modes identified could be characterized as (a) detectable/preventable before failures, (b) age-related failures, (c) random failures, (d) random/sudden failures, or (e) intermittent failures. The percentage of failure modes characterized as (a) was significant, implying that a significant reduction in system failures could be achieved through improved online monitoring, exhaustive testing prior to installation, adequate configuration control or verification and validation, etc.

Korsah, Kofi [ORNL; Cetiner, Mustafa Sacit [ORNL; Muhlheim, Michael David [ORNL; Poore III, Willis P [ORNL

2010-01-01T23:59:59.000Z

424

Genotype and ancestry modulate brain's DAT availability in healthy humans  

Science Conference Proceedings (OSTI)

The dopamine transporter (DAT) is a principal regulator of dopaminergic neurotransmission and its gene (the SLC6A3) is a strong biological candidate gene for various behavioral- and neurological disorders. Intense investigation of the link between the SLC6A3 polymorphisms and behavioral phenotypes yielded inconsistent and even contradictory results. Reliance on objective brain phenotype measures, for example, those afforded by brain imaging, might critically improve detection of DAT genotype-phenotype association. Here, we tested the relationship between the DAT brain availability and the SLC6A3 genotypes using an aggregate sample of 95 healthy participants of several imaging studies. These studies employed positron emission tomography (PET) with [{sup 11}C] cocaine wherein the DAT availability was estimated as Bmax/Kd; while the genotype values were obtained on two repeat polymorphisms - 3-UTR- and intron 8- VNTRs. The main findings are the following: (1) both polymorphisms analyzed as single genetic markers and in combination (haplotype) modulate DAT density in midbrain; (2) ethnic background and age influence the strength of these associations; and (3) age-related changes in DAT availability differ in the 3-UTR and intron8 - genotype groups.

Shumay, E.; Shumay, E.; Chen, J.; Fowler, J.S.; Volkow, N.D.

2011-08-01T23:59:59.000Z

425

Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications  

Science Conference Proceedings (OSTI)

Advanced glycation or glycoxidation end-products (AGE) increase in tissue proteins with age, and their rate of accumulation is increased in diabetes, nephropathy and inflammatory diseases. AGE inhibitors include a range of compounds that are proposed to act by trapping carbonyl and dicarbonyl intermediates in AGE formation. However, some among the newer generation of AGE inhibitors lack reactive functional groups that would trap reaction intermediates, indicating an alternative mechanism of action. We propose that AGE inhibitors function primarily as chelators, inhibiting metal-catalyzed oxidation reactions. The AGE-inhibitory activity of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers is also consistent with their chelating activity. Finally, compounds described as AGE breakers, or their hydrolysis products, also have strong chelating activity, suggesting that these compounds also act through their chelating activity. We conclude that chelation is the common, and perhaps the primary, mechanism of action of AGE inhibitors and breakers, and that chronic, mild chelation therapy should prove useful in treatment of diabetes and age-related diseases characterized by oxidative stress, inflammation and increased chemical modification of tissue proteins by advanced glycoxidation and lipoxidation end-products.

Nagai, Rhoji; Murray, David B.; Metz, Thomas O.; Baynes, John

2012-03-01T23:59:59.000Z

426

Nuclear power plant Generic Aging Lessons Learned (GALL). Appendix B  

SciTech Connect

The purpose of this generic aging lessons learned (GALL) review is to provide a systematic review of plant aging information in order to assess materials and component aging issues related to continued operation and license renewal of operating reactors. Literature on mechanical, structural, and thermal-hydraulic components and systems reviewed consisted of 97 Nuclear Plant Aging Research (NPAR) reports, 23 NRC Generic Letters, 154 Information Notices, 29 Licensee Event Reports (LERs), 4 Bulletins, and 9 Nuclear Management and Resources Council Industry Reports (NUMARC IRs) and literature on electrical components and systems reviewed consisted of 66 NPAR reports, 8 NRC Generic Letters, 111 Information Notices, 53 LERs, 1 Bulletin, and 1 NUMARC IR. More than 550 documents were reviewed. The results of these reviews were systematized using a standardized GALL tabular format and standardized definitions of aging-related degradation mechanisms and effects. The tables are included in volume s 1 and 2 of this report. A computerized data base has also been developed for all review tables and can be used to expedite the search for desired information on structures, components, and relevant aging effects. A survey of the GALL tables reveals that all ongoing significant component aging issues are currently being addressed by the regulatory process. However, the aging of what are termed passive components has been highlighted for continued scrutiny. This report consists of Volume 2, which consists of the GALL literature review tables for the NUMARC Industry Reports reviewed for the report.

Kasza, K.E.; Diercks, D.R.; Holland, J.W.; Choi, S.U. [and others

1996-12-01T23:59:59.000Z

427

Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor  

Science Conference Proceedings (OSTI)

Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP) developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cells in vivo after treatment of prostate cancer patients with DNA-damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial-mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL)-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment.

Copp, Jean-Philippe; Patil, Christopher; Rodier, Francis; Sun, Yu; Munoz, Denise; Goldstein, Joshua; Nelson, Peter; Desprez, Pierre-Yves; Campisi, Judith

2008-10-24T23:59:59.000Z

428

Boiling-Water Reactor internals aging degradation study. Phase 1  

SciTech Connect

This report documents the results of an aging assessment study for boiling water reactor (BWR) internals. Major stressors for BWR internals are related to unsteady hydrodynamic forces generated by the primary coolant flow in the reactor vessel. Welding and cold-working, dissolved oxygen and impurities in the coolant, applied loads and exposures to fast neutron fluxes are other important stressors. Based on results of a component failure information survey, stress corrosion cracking (SCC) and fatigue are identified as the two major aging-related degradation mechanisms for BWR internals. Significant reported failures include SCC in jet-pump holddown beams, in-core neutron flux monitor dry tubes and core spray spargers. Fatigue failures were detected in feedwater spargers. The implementation of a plant Hydrogen Water Chemistry (HWC) program is considered as a promising method for controlling SCC problems in BWR. More operating data are needed to evaluate its effectiveness for internal components. Long-term fast neutron irradiation effects and high-cycle fatigue in a corrosive environment are uncertainty factors in the aging assessment process. BWR internals are examined by visual inspections and the method is access limited. The presence of a large water gap and an absence of ex-core neutron flux monitors may handicap the use of advanced inspection methods, such as neutron noise vibration measurements, for BWR.

Luk, K.H. [Oak Ridge National Lab., TN (United States)

1993-09-01T23:59:59.000Z

429

Lightweight materials in the light-duty passenger vehicle market: Their market penetration potential and impacts  

DOE Green Energy (OSTI)

This paper summarizes the results of a lightweight materials study. Various lightweight materials are examined and the most cost effective are selected for further analysis. Aluminum and high-performance polymer matrix composites (PMCS) are found to have the highest potential for reducing the weight of automobiles and passenger-oriented light trucks. Weight reduction potential for aluminum and carbon fiber-based PMCs are computed based on a set of component-specific replacement criteria (such as stiffness and strength), and the consequent incremental cost scenarios are developed. The authors assume that a materials R and D program successfully reduces the cost of manufacturing aluminum and carbon fiber PMC-intensive vehicles. A vehicle choice model is used to project market shares for the lightweight vehicles. A vehicle survival and age-related usage model is employed to compute energy consumption over time for the vehicle stock. After a review of projected costs, the following two sets of vehicles are characterized to compete with the conventional materials vehicles: (1) aluminum vehicles with limited replacement providing 19% weight reduction (AIV-Mid), and (2) aluminum vehicles with the maximum replacement providing 31% weight reduction (AIV-Max). Assuming mass-market introduction in 2005, the authors project a national petroleum energy savings of 3% for AIV-Mid and 5% for AIV-Max in 2030.

Stodolsky, F. [Argonne National Lab., IL (United States). Center for Transportation Research]|[Argonne National Lab., Washington, DC (United States); Vyas, A.; Cuenca, R. [Argonne National Lab., IL (United States). Center for Transportation Research

1995-06-01T23:59:59.000Z

430

Oxidized-LDL induce morphological changes and increase stiffness of endothelial cells  

SciTech Connect

There is increasing evidence suggesting that oxidized low-density lipoproteins (ox-LDL) play a critical role in endothelial injury contributing to the age-related physio-pathological process of atherosclerosis. In this study, the effects of native LDL and ox-LDL on the mechanical properties of living human umbilical vein endothelial cells (HUVEC) were investigated by atomic force microscopy (AFM) force measurements. The contribution of filamentous actin (F-actin) and vimentin on cytoskeletal network organization were also examined by fluorescence microscopy. Our results revealed that ox-LDL had an impact on the HUVEC shape by interfering with F-actin and vimentin while native LDL showed no effect. AFM colloidal force measurements on living individual HUVEC were successfully used to measure stiffness of cells exposed to native and ox-LDL. AFM results demonstrated that the cell body became significantly stiffer when cells were exposed for 24 h to ox-LDL while cells exposed for 24 h to native LDL displayed similar rigidity to that of the control cells. Young's moduli of LDL-exposed HUVEC were calculated using two models. This study thus provides quantitative evidence on biomechanical mechanisms related to endothelial cell dysfunction and may give new insight on strategies aiming to protect endothelial function in atherosclerosis.

Chouinard, Julie A. [Laboratoire de Bioingenierie et de Biophysique de l'Universite de Sherbrooke, Department of Chemical Engineering, Universite de Sherbrooke, Sherbrooke, Quebec (Canada); Research Centre on Aging, Sherbrooke Geriatric University Institute, Sherbrooke, Quebec (Canada); Grenier, Guillaume [Research Centre on Aging, Sherbrooke Geriatric University Institute, Sherbrooke, Quebec (Canada); Department of Surgery, Service of Orthopaedic, Faculty of Medicine, Universite de Sherbrooke, Sherbrooke, Quebec (Canada); Khalil, Abdelouahed [Research Centre on Aging, Sherbrooke Geriatric University Institute, Sherbrooke, Quebec (Canada); Department of Medicine, Service of Geriatry, Faculty of Medicine, Universite de Sherbrooke, Sherbrooke, Quebec (Canada); Vermette, Patrick [Laboratoire de Bioingenierie et de Biophysique de l'Universite de Sherbrooke, Department of Chemical Engineering, Universite de Sherbrooke, Sherbrooke, Quebec (Canada); Research Centre on Aging, Sherbrooke Geriatric University Institute, Sherbrooke, Quebec (Canada)], E-mail: Patrick.Vermette@USherbrooke.ca

2008-10-01T23:59:59.000Z

431

Technical Basis Document: A Statistical Basis for Interpreting Urinary Excretion of Plutonium Based on Accelerator Mass Spectrometry (AMS) for Selected Atoll Populations in the Marshall Islands  

SciTech Connect

We have developed refined statistical and modeling techniques to assess low-level uptake and urinary excretion of plutonium from different population group in the northern Marshall Islands. Urinary excretion rates of plutonium from the resident population on Enewetak Atoll and from resettlement workers living on Rongelap Atoll range from <1 to 8 {micro}Bq per day and are well below action levels established under the latest Department regulation 10 CFR 835 in the United States for in vitro bioassay monitoring of {sup 239}Pu. However, our statistical analyses show that urinary excretion of plutonium-239 ({sup 239}Pu) from both cohort groups is significantly positively associated with volunteer age, especially for the resident population living on Enewetak Atoll. Urinary excretion of {sup 239}Pu from the Enewetak cohort was also found to be positively associated with estimates of cumulative exposure to worldwide fallout. Consequently, the age-related trends in urinary excretion of plutonium from Marshallese populations can be described by either a long-term component from residual systemic burdens acquired from previous exposures to worldwide fallout or a prompt (and eventual long-term) component acquired from low-level systemic intakes of plutonium associated with resettlement of the northern Marshall Islands, or some combination of both.

Bogen, K; Hamilton, T F; Brown, T A; Martinelli, R E; Marchetti, A A; Kehl, S R; Langston, R G

2007-05-01T23:59:59.000Z

432

THERMAL PERFORMANCE SENSITIVITY STUDIES IN SUPPORT OF MATERIAL MODELING FOR EXTENDED STORAGE OF USED NUCLEAR FUEL  

SciTech Connect

The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.

Cuta, Judith M.; Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.

2013-08-15T23:59:59.000Z

433

THE DYNAMICAL DISTANCE, RR LYRAE ABSOLUTE MAGNITUDE, AND AGE OF THE GLOBULAR CLUSTER NGC 6266  

SciTech Connect

The internal proper motion dispersion of NGC 6266 was measured using Hubble Space Telescope Wide Field Planetary Camera 2 images with an epoch difference of eight years. The dispersion was found to be 0.041 {+-} 0.001 arcsec century{sup -1}. This value was then equated to the cluster's radial velocity dispersion of 13.7 {+-} 1.1 km s{sup -1} to yield a distance to NGC 6266 of 7054 {+-} 583 pc. Based on this distance we find that the NGC 6266 RR Lyrae stars have M{sub V} = 0.51 {+-} 0.18 mag. This magnitude is in good agreement with that predicted by the M{sub V} versus [Fe/H] relation found by Benedict et al. Using an average [Fe/H] of -1.25 for NGC 6266, their relation predicts M{sub V} = 0.49 {+-} 0.06. Based on the RR Lyrae M{sub V} versus age relation determined by Chaboyer et al., we estimate that NGC 6266 has an age of 11.4 {+-} 2.2 Gyr.

McNamara, Bernard J.; McKeever, Jean, E-mail: bmcnamar@nmsu.edu, E-mail: jeanm12@nmsu.edu [Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States)

2011-11-15T23:59:59.000Z

434

Optimization of Two-photon Excited Fluorescence Enhancement between Tunable and Broadband Femtosecond Laser Pulse Excitations  

E-Print Network (OSTI)

This project explores optimization of two-photon excited fluorescence (TPEF) enhancement between tunable narrowband and un-tuned broadband femtosecond (fs) laser pulse excitations for two-photon microscopy (TPM). The research is conducted preliminarily in time domain and comprehensively in frequency domain to understand the physics behind TPEF enhancement by un-tuned sub-10 fs nearly transform-limited pulse (TLP) versus tunable 140 fs pulse. The preliminary study on inverse proportionality of TPEF yield to fs-pulse duration delimits a general lower-bound to narrowband fs-pulse regime (pulse duration > 40 fs) with assumption of dye-molecule frequency invariant response. Deviations from this inverse proportionality in broadband fs-pulse regime (pulse duration < 40 fs) highlights dye-molecule frequency variant response, necessity of group delay dispersion (GDD) compensation, and broadband TLP for TPEF enhancement. The follow-up comparative study is made on un-tuned sub-10 fs TLP versus tunable 140 fs pulse excitations using three dye-phantoms (Indo-1, FITC, and TRITC) representative of fluorescent probes with similar TPEF characteristics. The integrated experimental system, with custom-designed GDD compensation, dispersion-less laser-beam expanding and focusing, and compound-lens for efficient fluorescence collection with good spectral resolution, ensures accurate TPEF measurements. Differentiated TPEF enhancements of Indo-1 (1.6), FITC (6.7), and TRITC (5.2) proportionally agree with calculated ones due to the overlap of fs-pulse second harmonic (SH) power spectrum with dye-molecule two-photon excitation (TPE) spectrum. Physically speaking, with broadband sub-10 fs TLP readily involved in both degenerate (v1 = v2) and non-degenerate (v1 ? v2) two-photon absorption (TPA), this un-tuned ultrashort fs-pulse excitation simultaneously allows for more accessibility to TPA-associated final states and diversely promotes population of thus excited dye-molecules with the three dye-phantoms. Under environmental influences (mutual quenching through one-photon absorption(s) and solvent effect), multicolor TPEF enhancement observed from a mixture of the three dyes shows promise of sub-10 fs TLP as simultaneous excitation for multiple-dye labeled samples in contrast to compromised excitation with narrowband fs-pulse tuning. Both single- and multicolor TPEF enhancements clarify tradeoff between tunability of narrowband fs-pulse and un-tuned broadband fs-pulse excitations, being instructive to further considerations on optimization of TPEF enhancement by strategic utilization of broadband fs-pulse for better performance of TPM.

Wang, Chao

2011-12-01T23:59:59.000Z

435

Early pregnancy diagnosis and embryo/fetus mortality in cattle  

E-Print Network (OSTI)

Pregnancy diagnosis by transrectal ultrasonography (using a 5 MHZ linear probe) presented the maximum sensitivity and negative predictive values at day 26 and day 29 after estrus in heifers and cows, respectively. Palpation per rectum using the fetal membrane slip for pregnancy diagnosis did not increase embryo/fetus mortality when compared with a positive control group of non-palpated females. The use of a controlled randomized block design was a useful approach to study this problem. Blocking for category and number of embryos allowed us to remove these confounding factors. Factors that affected pregnancy loss during the first four months of pregnancy were: period of pregnancy, age of the animal, number of previous lactations and number of embryos. Pregnancy loss was higher during the embryonic than fetal periods. Spontaneous embryo/fetal mortality increased with the age of the animal and lactation number. The risk of spontaneous embryo/fetus mortality was higher in twin than in single pregnancies. Two types of embryo/fetus mortality were noted: Type I and Type II. Type I was characterized by presence of positive fetal membrane slip by palpation per rectum, signs of degeneration by transrectal ultrasonography and persistence of a functional corpus luteum. The uterus took approximately 3 weeks to be noted clean by transrectal ultrasonography and the animals showed estrus one month after the conceptus was diagnosed dead. Type II was characterized by absence of positive signs of pregnancy by palpation per rectum, absence of signs of degeneration by transrectal ultrasonography and absence of a functional corpus luteum. Pregnancy loss in nuclear transfer derived embryos was higher compared to in vivo derived embryos produced by artificial insemination. Pregnancy loss occurred mainly during the transition from the embryonic to the fetal period. Embryo/fetus mortality detected was Type I. Progesterone produced by the corpus luteum was noted at pregnancy levels for approximately two weeks after embryo/fetus death. Protein B, a hormonal placental marker, was maintained at pregnancy levels for approximately 3 weeks after embryo/fetus death. No differences in the levels of the two hormones were noted when comparing females with dead or live conceptuses.

Romano, Juan Eduardo

2004-12-01T23:59:59.000Z

436

Conspecific and Interspecific Interactions Between the FEM-2 and the FEM-3 Sex-Determining Proteins Despite Rapid Sequence Divergence  

E-Print Network (OSTI)

Abstract. Using degenerate oligonucleotide primers, we isolated the Caenorhabditis remanei orthologue of the C. elegans sex-determining phosphatase gene fem-2 as well as two other protein phosphatase homologues. Despite the significant sequence divergence between C. elegans and C. remanei FEM-2, we used RNAi-mediated gene knockdown to demonstrate that at least some aspects of male development require FEM-2 function in C. remanei. Consistent with this functional conservation, the conspecific interaction between the FEM-2 and the FEM-3 proteins observed in C. elegans also occurs in C. remanei. To further explore whether the rapid evolution of FEM-2 and FEM-3 affects their molecular interactions, we tested for cross-species interactions between the proteins from C. elegans, C. briggsae, and C. remanei. Although all FEM-2/FEM-3 pairs from a single species interact, only two out of six interspecific pairs bind each other, showing that FEM-2 and FEM-3 are coevolving. Both interspecific interactions involved C. briggsae FEM-3. We constructed chimeric versions of FEM-2 consisting of various combinations of the C. elegans and C. remanei proteins. C. briggsae FEM-3 interacted with all the chimeras, even those that did not interact with either C. elegans or C. remanei FEM-3. We hypothesize that the promiscuity of C. briggsae FEM-3 reflects an increased reliance on evolutionarily constrained regions of FEM-2 for binding. If so, our data support the notion that the Correspondence to: David Pilgrim;

Paul Stothard; David Pilgrim

2005-01-01T23:59:59.000Z

437

Classically spinning and isospinning solitons  

SciTech Connect

We investigate classically spinning topological solitons in (2+1)- and (3+1)-dimensional models; more explicitely spinning sigma model solitons in 2+1 dimensions and Skyrme solitons in 2+1 and 3+1 dimensions. For example, such types of solitons can be used to describe quasiparticle excitations in ferromagnetic quantum Hall systems or to model spin and isospin states of nuclei. The standard way to obtain solitons with quantised spin and isospin is the semiclassical quantization procedure: One parametrizes the zero-mode space - the space of energy-degenerate soliton configurations generated from a single soliton by spatial translations and rotations in space and isospace - by collective coordinates which are then taken to be time-dependent. This gives rise to additional dynamical terms in the Hamiltonian which can then be quantized following semiclassical quantization rules. A simplification which is often made in the literature is to apply a simple adiabatic approximation to the (iso)rotational zero modes of the soliton by assuming that the soliton's shape is rotational frequency independent. Our numerical results on classically spinning arbitrarily deforming soliton solutions clearly show that soliton deformation cannot be ignored.

Battye, Richard A.; Haberichter, Mareike [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-09-26T23:59:59.000Z

438

Spin glass transition in a magnetic field: a renormalization group study  

E-Print Network (OSTI)

We study the transition of short range Ising spin glasses in a magnetic field, within a general replica symmetric field theory, which contains three masses and eight cubic couplings, that is defined in terms of the fields representing the replicon, anomalous and longitudinal modes. We discuss the symmetry of the theory in the limit of replica number n ? 0, and consider the regular case where the longitudinal and anomalous masses remain degenerate. The spin glass transitions in zero and non-zero field are analyzed in a common framework. The mean field treatment shows the usual results, that is a transition in zero field, where all the modes become critical, and a transition in nonzero field, at the de Almeida-Thouless (AT) line, with only the replicon mode critical. Renormalization group methods are used to study the critical behavior, to order ? = 6 ? d. In the general theory we find a stable fixed-point associated to the spin glass transition in zero field. This fixed-point becomes unstable in the presence of a small magnetic field, and we calculate crossover exponents, which we relate to zero-field critical exponents. In a finite magnetic field, we find no physical stable fixed-point to describe the AT transition, in agreement with previous results of other authors. PACS numbers: 75.50.Lk, 75.40.Cx 1 I

I. R. Pimentel; T. Temesvri; C. De Dominicis

2002-01-01T23:59:59.000Z

439

Trigonometry of spacetimes: a new self-dual approach to a curvature/signature (in)dependent trigonometry  

E-Print Network (OSTI)

A new method to obtain trigonometry for the real spaces of constant curvature and metric of any (even degenerate) signature is presented. The method encapsulates trigonometry for all these spaces into a single basic trigonometric group equation. This brings to its logical end the idea of an absolute trigonometry, and provides equations which hold true for the nine two-dimensional spaces of constant curvature and any signature. This family of spaces includes both relativistic and non-relativistic homogeneous spacetimes; therefore a complete discussion of trigonometry in the six de Sitter, minkowskian, Newton--Hooke and galilean spacetimes follow as particular instances of the general approach. Any equation previously known for the three classical riemannian spaces also has a version for the remaining six spacetimes; in most cases these equations are new. Distinctive traits of the method are universality and self-duality: every equation is meaningful for the nine spaces at once, and displays explicitly invariance under a duality transformation relating the nine spaces. The derivation of the single basic trigonometric equation at group level, its translation to a set of equations (cosine, sine and dual cosine laws) and the natural apparition of angular and lateral excesses, area and coarea are explicitly discussed in detail. The exposition also aims to introduce the main ideas of this direct group theoretical way to trigonometry, and may well provide a path to systematically study trigonometry for any homogeneous symmetric space.

Francisco J. Herranz; Ramon Ortega; Mariano Santander

1999-10-26T23:59:59.000Z

440

Tetratic order in the phase behavior of a hard-rectangle system  

Science Conference Proceedings (OSTI)

Previous Monte Carlo investigations by Wojciechowski et al. have found two unusual phases in two-dimensional systems of anisotropic hard particles: a tetratic phase of fourfold symmetry for hard squares [Comput. Methods Sci. Tech. 10, 235 (2004)], and a nonperiodic degenerate solid phase for hard-disk dimers [Phys. Rev. Lett. 66, 3168 (1991)]. In this work, we study a system of hard rectangles of aspect ratio two, i.e., hard-square dimers (or dominos), and demonstrate that it exhibits phases with both of these unusual properties. The liquid shows quasi-long-range tetratic order, with no nematic order. The solid phase we observe is a nonperiodic tetratic phase having the structure of a random tiling of the square lattice with dominos with the well-known degeneracy entropy 1.79k{sub B} per particle. Our simulations do not conclusively establish the thermodynamic stability of this orientationally disordered solid; however, there are strong indications that this phase is glassy. Our observations are consistent with a two-stage phase transition scenario developed by Kosterlitz and co-workers with two continuous phase transitions, the first from isotropic to tetratic liquid, and the second from tetratic liquid to solid. We obtain similar results with both a classical Monte Carlo method using true rectangles and a novel molecular dynamics algorithm employing rectangles with rounded corners.

Donev, Aleksandar [Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544 (United States); PRISM, Princeton University, Princeton, New Jersey 08544 (United States); Burton, Joshua [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States); Stillinger, Frank H. [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States); Torquato, Salvatore [Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544 (United States); PRISM, Princeton University, Princeton, New Jersey 08544 (United States); Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)

2006-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Beyond Landauer erasure  

E-Print Network (OSTI)

In thermodynamics one considers thermal systems and the maximization of entropy subject to the conservation of energy. A consequence is Landauer's erasure principle, which states that the erasure of 1 bit of information requires a minimum energy cost equal to $kT\\ln(2)$ where $T$ is the temperature of a thermal reservoir used in the process and $k$ is Boltzmann's constant. Jaynes, however, argued that the maximum entropy principle could be applied to any number of conserved quantities which would suggest that information erasure may have alternative costs. Indeed we showed recently that by using a reservoir comprising energy degenerate spins and subject to conservation of angular momentum, the cost of information erasure is in terms of angular momentum rather than energy. Here we extend this analysis and derive the minimum cost of information erasure for systems where different conservation laws operate. We find that, for each conserved quantity, the minimum resource needed to erase 1 bit of memory is $\\lambda^{-1}\\ln(2)$ where $\\lambda$ is related to the average value of the conserved quantity. The costs of erasure depend, fundamentally, on both the nature of the physical memory element and the reservoir with which it is coupled.

Stephen M. Barnett; Joan A. Vaccaro

2013-10-29T23:59:59.000Z

442

Memory, Bias and Correlations in Bidirectional Transport of Molecular Motor-driven Cargoes  

E-Print Network (OSTI)

Molecular motors are specialized proteins which perform active, directed transport of cellular cargoes on cytoskeletal filaments. In many cases, cargo motion powered by motor proteins is found to be bidirectional, and may be viewed as a biased random walk with fast unidirectional runs interspersed with slow `tug-of-war' states. The statistical properties of this walk are not known in detail, and here, we study memory and bias, as well as directional correlations between successive runs in bidirectional transport. We show, based on a study of the direction reversal probabilities of the cargo using a purely stochastic (tug-of-war) model, that bidirectional motion of cellular cargoes is, in general, a correlated random walk. In particular, while the motion of a cargo driven by two oppositely pulling motors is a Markovian random walk, memory of direction appears when multiple motors haul the cargo in one or both directions. In the latter case, the Markovian nature of the underlying single motor processes is hidden by internal transitions between degenerate run and pause states of the cargo. Interestingly, memory is found to be a non-monotonic function of the number of motors. Stochastic numerical simulations of the tug-of-war model support our mathematical results and extend them to biologically relevant situations.

Deepak Bhat; Manoj Gopalakrishnan

2013-08-13T23:59:59.000Z

443

Neuromorphic quantum computation with energy dissipation  

SciTech Connect

Real parallel computing with a quantum computer attracts vast interest due to its extreme high potential. We propose a neuromorphic quantum computation algorithm based on an adiabatic Hamiltonian evolution with energy dissipation. This algorithm can be applied to problems if a cost function can be expressed in a quadratic form. This requirement results from the fact that our Hamiltonian is designed by following a method similar to an artificial neural network (ANN). The state of an ANN is often trapped at local minima, and the network outputs an error. Since the state of a quantum system with the proposed algorithm is always in the ground state according to the adiabatic theorem, it is not necessary to be concerned that the quantum state is trapped at local minima. However, there is no guarantee that a quantum algorithm based on an adiabatic Hamiltonian evolution with degeneration or level crossing is successfully executed. We show successful numerical simulation results with the proposed algorithm by introducing energy dissipation to keep the quantum state staying in the ground state, and then we show an application to the n-queen problem, which is one of the combinatorial optimization problems.

Kinjo, Mitsunaga; Sato, Shigeo; Nakamiya, Yuuki; Nakajima, Koji [Laboratory for Brainware Systems, Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 980-8577, 2-1-1 Katahira, Aoba-ku, Sendai (Japan)

2005-11-15T23:59:59.000Z

444

Superfluid and magnetic states of an ultracold Bose gas with synthetic three-dimensional spin-orbit coupling in an optical lattice  

E-Print Network (OSTI)

We study ultracold bosonic atoms with the synthetic three-dimensional spin-orbit (SO) coupling in a cubic optical lattice. In the superfluidity phase, the lowest energy band exhibits one, two or four pairs of degenerate single-particle ground states depending on the SO-coupling strengths, which can give rise to the condensate states with spin-stripes for the weak atomic interactions. In the deep Mott-insulator regime, the effective spin Hamiltonian of the system combines three-dimensional Heisenberg exchange interactions, anisotropy interactions and Dzyaloshinskii-Moriya interactions. Based on Monte Carlo simulations, we numerically demonstrate that the resulting Hamiltonian with an additional Zeeman field has a rich phase diagram with spiral, stripe, vortex crystal, and especially Skyrmion crystal spin-textures in each xy-plane layer. The obtained Skyrmion crystals can be tunable with square and hexagonal symmetries in a columnar manner along the z axis, and moreover are stable against the inter-layer spin-spin interactions in a large parameter region.

Dan-Wei Zhang; Ji-Pei Chen; Chuan-Jia Shan; Z. D. Wang; Shi-Liang Zhu

2013-01-14T23:59:59.000Z

445

NEWTON, Ask a Scientist at Argonne National Labs  

NLE Websites -- All DOE Office Websites (Extended Search)

Male Development Male Development Name: Kurt Status: other Grade: other Location: Outside U.S. Country: Brazil Date: Spring 2012 Question: I heard that the male fetus has to go through stages to definitely become a male - that all fetuses are initially female, and that only after 8 weeks does the male fetus develop testicles, and that after that, I understand there are 3 more stages of development for the fetus to go through before definitely becoming male. What are these stages? Replies: Embryos are male or female from the moment of conception because they have either XX or XY chromosomes. But they don't start to develop their sexual phenotypes for about 6-8 weeks. Embryos have two nonspecific gonads and two sets of nonspecific tubes. If there is a Y chromosome, a gene called SRY turns on around 6-8 weeks and starts male development. The nonspecific gonads become testes and the tubes become the vas deferens. It causes the second set of tubes to degenerate. It also causes the testes to begin secreting testosterone which also adds to the masculine phenotype. There is a step by step process that happens. If there is a block in the process everything stops there. So some parts could develop and others not.For instance, internal structures might develop but external not. This would result in an ambiguous phenotype which may be mistaken for a female.

446

Rotational Invariance, Phase Relationships and the Quantum Entanglement Illusion  

E-Print Network (OSTI)

Another Bell test "loophole" - imperfect rotational invariance - is explored, and novel realist ideas on parametric down-conversion as used in recent "quantum entanglement" experiments are presented. The usual quantum theory of entangled systems assumes we have rotational invariance (RI), so that coincidence rates depend on the difference only between detector settings, not on the absolute values. Bell tests, as such, do not necessarily require RI, but where it fails the presentation of results in the form of coincidence curves can be grossly misleading. Even if the well-known detection loophole were closed, the visibility of such curves would tell us nothing about the degree of entanglement! The problem may be especially relevant to recent experiments using "degenerate type II parametric down-conversion" sources. Logical analysis of the results of many experiments suggests realist explanations involving some new physics. The systems may be more nearly deterministic than quantum theory implies. Whilst this may be to the advantage of those attempting to make use of the so-called "Bell correlations" in computing, encryption, "teleportation" etc., it does mean that the systems obey ordinary, not quantum, logic.

Caroline H Thompson

1999-12-16T23:59:59.000Z

447

Micro-Kelvin cold molecules.  

SciTech Connect

We have developed a novel experimental technique for direct production of cold molecules using a combination of techniques from atomic optical and molecular physics and physical chemistry. The ability to produce samples of cold molecules has application in a broad spectrum of technical fields high-resolution spectroscopy, remote sensing, quantum computing, materials simulation, and understanding fundamental chemical dynamics. Researchers around the world are currently exploring many techniques for producing samples of cold molecules, but to-date these attempts have offered only limited success achieving milli-Kelvin temperatures with low densities. This Laboratory Directed Research and Development project is to develops a new experimental technique for producing micro-Kelvin temperature molecules via collisions with laser cooled samples of trapped atoms. The technique relies on near mass degenerate collisions between the molecule of interest and a laser cooled (micro-Kelvin) atom. A subset of collisions will transfer all (nearly all) of the kinetic energy from the 'hot' molecule, cooling the molecule at the expense of heating the atom. Further collisions with the remaining laser cooled atoms will thermally equilibrate the molecules to the micro-Kelvin temperature of the laser-cooled atoms.

Strecker, Kevin E.; Chandler, David W.

2009-10-01T23:59:59.000Z

448

Investigation of ac-Stark shifts in excited states of dysprosium relevant to testing fundamental symmetries  

E-Print Network (OSTI)

We report on measurements of the differential polarizability between the nearly degenerate, opposite parity states in atomic dysprosium at 19797.96 cm$^{-1}$. The differential scalar and tensor polarizabilities due to additional states were measured for the $|M| = 7,...,10$ sublevels in $^{164}$Dy and $^{162}$Dy and determined to be $\\bar{\\balpha}_{\\sss BA}^{(0)} = 180\\,(45)_\\text{stat}\\,(8)_\\text{sys}$ $\\text{mHz}/(\\mathrm{V}/\\mathrm{cm})^2$ and $\\bar{\\balpha}_{\\sss BA}^{(2)} = -163\\,(65)_\\text{stat}\\,(5)_\\text{sys}$ $\\text{mHz}/(\\mathrm{V}/\\mathrm{cm})^2$, respectively. The average blackbody radiation induced Stark shift of the Zeeman spectrum was measured around 300 K and found to be $-34(4)$ mHz/K and $+29(4)$ mHz/K for $^{164}$Dy and $^{162}$Dy, respectively. We conclude that ac-Stark related systematics will not limit a search for variation of the fine-structure constant, using dysprosium, down to the level of $|\\dot{\\alpha}/\\alpha|=2.6\\times10^{-17}$ yr$^{-1}$, for two measurements of the transition fr...

Weber, C T M; Budker, D

2013-01-01T23:59:59.000Z

449

HH Domain of Alzheimers Disease Ab Provides Structural Basis for Neuronal Binding in PC12 and Mouse Cortical/Hippocampal Neurons  

E-Print Network (OSTI)

A key question in understanding AD is whether extracellular Ab deposition of parenchymal amyloid plaques or intraneuronal Ab accumulation initiates the AD process. Amyloid precursor protein (APP) is endocytosed from the cell surface into endosomes where it is cleaved to produce soluble Ab which is then released into the brain interstitial fluid. Intraneuronal Ab accumulation is hypothesized to predominate from the neuronal uptake of this soluble extracellular Ab rather than from ER/Golgi processing of APP. We demonstrate that substitution of the two adjacent histidine residues of Ab40 results in a significant decrease in its binding with PC12 cells and mouse cortical/hippocampal neurons. These substitutions also result in a dramatic enhancement of both thioflavin-T positive fibril formation and binding to preformed Ab fibrils while maintaining its plaque-binding ability in AD transgenic mice. Hence, alteration of the histidine domain of Ab prevented neuronal binding and drove Ab to enhanced fibril formation and subsequent amyloid plaque deposition- a potential mechanism for removing toxic species of Ab. Substitution or even masking of these Ab histidine residues might provide a new therapeutic direction for minimizing neuronal uptake and subsequent neuronal degeneration and

Joseph F. Poduslo; Emily J. Gilles; Muthu Ramakrishnan; Kyle G. Howell; Thomas M. Wengenack; Geoffry L. Curran; Karunya K. K

2010-01-01T23:59:59.000Z

450

Transverse spin diffusion in strongly interacting Fermi gases  

E-Print Network (OSTI)

We compute spin diffusion in a dilute Fermi gas at arbitrary temperature, polarization and strong interaction in the normal phase using kinetic theory. While the longitudinal spin diffusivity depends weakly on polarization and diverges for small temperatures, the transverse spin diffusivity D_\\perp has a strong polarization dependence and approaches a finite value for T->0 in the Fermi liquid phase. For a 3D unitary Fermi gas at infinite scattering length the diffusivities reach a minimum near the quantum limit of diffusion \\hbar/m in the quantum degenerate regime and are strongly suppressed by medium scattering, and we discuss the importance of the spin-rotation effect. In two dimensions, D_\\perp attains a minimum at strong coupling -1 < ln(kFa2D) < 1 and reaches D_\\perp~0.2...0.3\\hbar/m at large polarization. These values are consistent with recent measurements of two-dimensional ultracold atomic gases in the strong coupling regime.

Tilman Enss

2013-07-19T23:59:59.000Z

451

Pharmacology and  

E-Print Network (OSTI)

Aberrant aggregation of ?-synuclein (?-syn) to form fibrils and insoluble aggregates has been implicated in the pathogenic processes of many neurodegenerative diseases. Despite the dramatic effects of dopamine in inhibiting the formation of ?-syn fibrils by stabilization of oligomeric intermediates in cell-free systems, no studies have examined the effects of intracellular dopamine on ?-syn aggregation. To study this process and its association with neurodegeneration, intracellular catechol levels were increased to various levels by expressing different forms of tyrosine hydroxylase, in cells induced to form ?-syn aggregates. The increase in the steady-state dopamine levels inhibited the formation of ?-syn aggregates and induced the formation of innocuous oligomeric intermediates. Analysis of transgenic mice expressing the disease-associated A53T mutant ?-syn revealed the presence of oligomeric ?-syn in nondegenerating dopaminergic neurons that do contain insoluble ?-syn. These data indicate that intraneuronal dopamine levels can be a major modulator of ?-syn aggregation and inclusion formation, with important implications on the selective degeneration of these neurons in Parkinsons disease. Key words: ?-synuclein; catecholamines; neurodegeneration; Parkinsons disease; tyrosine hydroxylase; protein aggregation

Joseph R. Mazzulli; A J. Mishizen; Benoit I. Giasson; David R. Lynch; Steven A. Thomas; Akira Nakashima; Toshiharu Nagatsu; Akira Ota; Harry Ischiropoulos

2006-01-01T23:59:59.000Z

452

Catechol oxidation by peroxidase-positive astrocytes in primary culture: an electron spin resonance study  

E-Print Network (OSTI)

In rodents, chronic estrogenization has been shown to induce degeneration of dendrites and myelin figures in the hypothalamic arcuate nucleus adjacent to peroxidase-positive astrocyte processes. Because in this brain region estradiol is metabolized to 2-hydroxyestradiol (catecholestrogen), we hypothesized that the latter may be oxidized by the astrocytic peroxidase activity to cytotoxic ortho-semiquinones as occurs in peripheral tissues. Cysteamine induces nonenzymatic peroxidase activity in cultured astroglia identical to that observed in viva. Using electron spin resonance, we demonstrate robust peroxidase-catalyzed oxidation of 2-hydroxyestradiol and dopamine by cysteaminepretreated astrocyte cultures relative to untreated controls. These results implicate the peroxidase-positive astrocytes in the pathogenesis of estradiol-related hypothalamic damage, parkinsonism, and other free-radical-related neurologic disorders. A distinct subpopulation of granule-laden astrocytes exhibiting an affinity for chrome alum hematoxylin and aldehyde fuchsin (Gomori stains) has been described in the periventricular brain of many vertebrates, including humans. Their cytoplasmic inclusions are rich in sulfhydryl groups, emit an orange-red autofluorescence, and stain intensely with diaminobenzidine (DAB), a marker ofendogenous peroxidase activity (Diepen et al., 1954; Creswell et al., 1964; Srebro, 197 1; Goldgefter, 1976; Schipper et al., 1988). Histochemical studies have implicated porphyrins and metalloporphyrins (heme) as the source of the autofluorescence and nonenzymatic peroxidase activity in these cells, respectively

Yashige Kotake; Edward G. Janzen

1991-01-01T23:59:59.000Z

453

Force-Free Magnetosphere of an Accreting Kerr Black Hole  

E-Print Network (OSTI)

I consider a stationary axisymmetric force-free degenerate magnetosphere of a rotating Kerr black hole surrounded by a thin Keplerian infinitely-conducting accretion disk. I focus on the closed-field geometry with a direct magnetic coupling between the disk and the event horizon. I first present a simple physical argument that shows how the black hole's rotation limits the radial extent of the force-free link. I then confirm this result by solving numerically the general-relativistic force-free Grad--Shafranov equation in the magnetosphere, using the regularity condition at the inner light cylinder to determine the poloidal current. I indeed find that force-free solutions exist only when the magnetic link between the hole and the disk has a limited extent on the disk surface. I chart out the maximum allowable size of this magnetically-connected part of the disk as a function of the black hole spin. I also compute the angular momentum and energy transfer between the hole and the disk that takes place via the direct magnetic link. I find that both of these quantities grow rapidly and that their deposition becomes highly concentrated near the inner edge of the disk as the black hole spin is increased.

Dmitri A. Uzdensky

2005-03-23T23:59:59.000Z

454

The discrete flavor symmetry D5  

E-Print Network (OSTI)

We consider the standard model (SM) extended by the flavor symmetry D5 and search for a minimal model leading to viable phenomenology. We find that it contains four Higgs fields apart from the three generations of fermions whose left- and left-handed conjugate parts do not transform in the same way under D5. We provide two numerical fits for the case of Dirac and Majorana neutrinos to show the viability of our low energy model. The fits can accommodate all data with the neutrinos being normally ordered. For Majorana neutrinos two of the right-handed neutrinos are degenerate. Concerning the Higgs sector we find that all potentials constructed with three SM-like Higgs doublets transforming as 1+2 under D5 have a further unwanted global U(1) symmetry. Therefore we consider the case of four Higgs fields forming two D5 doublets and show that this potential leads to viable solutions in general, however it does not allow spontaneous CP-violation (SCPV) for an arbitrary vacuum expectation value (VEV) configuration. Finally, we discuss extensions of our model to grand unified theories (GUTs) as well as embeddings of D5 into the continuous flavor symmetries SO(3)_f and SU(3)_f.

C. Hagedorn; M. Lindner; F. Plentinger

2006-04-28T23:59:59.000Z

455

Nonlinear Optical Signatures of the Tensor Order in Cd2Re2O7  

Science Conference Proceedings (OSTI)

Growing evidence indicates that the superconducting pyrochlore Cd2Re2O7 exhibits a structural phase transition at Tc=200K with an unusual tensor character. The structural order parameter for this state is two-dimensional, and spanned by distinct but nearly degenerate crystallographic structures I4{sub 1}22. Symmetry rules imply that the low-energy excitations of the ordered state are Goldstone phonons, or long wavelength fluctuations between the two crystal structures. These are the structural equivalents of magnons in an XY antiferromagnet, with the two crystal structures analogous to orthogonal spin directions in the xy-plane. Goldstone phonons have been observed in Raman spectroscopy3, but high-resolution X-ray and neutron scattering experiments have produced conflicting assignments of the static low-temperature structure. Here, we use optical second-harmonic generation with polarization sensitivity to assign I4M2 structure unambiguously and verify an auxiliary condition on the structure that is implied by the order parameter symmetry. We also show that the temperature dependence of the order parameter is consistent with thermal occupation of the Goldstone mode. The methodology may be applied more widely in characterizing ordered states in matter.

Petersen, Jesse C. [Simon Fraser University, Canada; Caswell, Michael D. [Simon Fraser University, Canada; Dodge, J. Steven [Simon Fraser University, Canada; Sergienko, Ivan A [ORNL; He, J [University of Tennessee, Knoxville (UTK); Jin, Rongying [ORNL; Mandrus, David [ORNL

2006-01-01T23:59:59.000Z

456

Cosmological bounds on neutrino degeneracy improved by flavor oscillations  

E-Print Network (OSTI)

We study three-flavor neutrino oscillations in the early universe in the presence of neutrino chemical potentials. We take into account all effects from the background medium, i.e. collisional damping, the refractive effects from charged leptons, and in particular neutrino self-interactions that synchronize the neutrino oscillations. We find that effective flavor equilibrium between all active neutrino species is established well before the big-bang nucleosynthesis (BBN) epoch if the neutrino oscillation parameters are in the range indicated by the atmospheric neutrino data and by the large mixing angle (LMA) MSW solution of the solar neutrino problem. For the other solutions of the solar neutrino problem, partial flavor equilibrium may be achieved if the angle theta_13 is close to the experimental limit tan^2(theta_13)radiation contribution from degenerate neutrinos is limited to such low values that it is neither observable in the large-scale structure of the universe nor in the anisotropies of the cosmic microwave background radiation. Existing limits and possible future measurements, for example in KATRIN, of the absolute neutrino mass scale will provide unambiguous information on the cosmic neutrino mass density, essentially free of the uncertainty of the neutrino chemical. potentials.

A. D. Dolgov; S. H. Hansen; S. Pastor; S. T. Petcov; G. G. Raffelt; D. V. Semikoz

2002-01-30T23:59:59.000Z

457

Light and Superlight Sterile Neutrinos in the Minimal Radiative Inverse Seesaw Model  

E-Print Network (OSTI)

We explore the possibility of light and superlight sterile neutrinos in the recently proposed Minimal Radiative Inverse Seesaw extension of the Standard Model for neutrino masses, in which all existing neutrino data can be explained. In particular, we discuss two benchmark scenarios with one of the three sterile neutrino states in the keV-range, having very small mixing with the active neutrinos to account for the Dark Matter in the Universe, while (i) the other two light sterile neutrino states could be in the eV-range, possessing a nonzero mixing with the active states as required to explain the LSND+MiniBooNE+reactor neutrino data, or (ii) one of the light sterile states is in the eV-range, whereas the second one could be superlight and almost mass-degenerate with the solar neutrinos. Such superlight sterile neutrinos could give rise to potentially observable effects in future neutrino oscillation experiments and may also offer a possible explanation for the extra radiation observed in the Universe.

P. S. Bhupal Dev; Apostolos Pilaftsis

2012-12-16T23:59:59.000Z

458

Charged Higgs and Neutral Higgs pair production of weak gauge bosons fusion process in e+ e- collision  

E-Print Network (OSTI)

In this paper, we study the pair production and their decays of the Higges in the neutrinophilic Higgs two doublet model. The pair production occurs through W and Z gauge bosons fusion process. In the neutrinophilic model, the vacuum expectation value (VEV) of the second Higgs doublet is small and is proportional to the neutrino mass. The smallness of VEV is associated with the approximate global U(1) symmetry which is slightly broken. Therefore, there is a suppression factor for the U(1) charge breaking process. The second Higgs doublet has U(1) charge and its single production from the gauge boson fusion violates the U(1) charge conservation and is suppressed strongly to occur. In contrast to the single production, the pair production of the Higgses conserves U(1) charge and the approximate symmetry does not forbid it. To search for the pair productions in collider experiment,we study the production cross section of a pair of the charged Higgs and neutral Higgs bosons in e+ e- collision with center of energy from 600 (GeV) to 2000 (GeV). The total cross section varies from 10^{-4}(fb) to 10^{-3}(fb) for degenerate (200 GeV) charged and neutral Higgses mass case. The background process to the signal is gauge bosons pair W + Z production and their decays. We show the signal over background ratio is about 2% ~ 3% by combining the cross section ratio with ratios of branching fractions.

Takuya Morozumi; Kotaro Tamai

2013-06-07T23:59:59.000Z

459

AB INITIO SIMULATIONS FOR MATERIAL PROPERTIES ALONG THE JUPITER ADIABAT  

SciTech Connect

We determine basic thermodynamic and transport properties of hydrogen-helium-water mixtures for the extreme conditions along Jupiter's adiabat via ab initio simulations, which are compiled in an accurate and consistent data set. In particular, we calculate the electrical and thermal conductivity, the shear and longitudinal viscosity, and diffusion coefficients of the nuclei. We present results for associated quantities like the magnetic and thermal diffusivity and the kinematic shear viscosity along an adiabat that is taken from a state-of-the-art interior structure model. Furthermore, the heat capacities, the thermal expansion coefficient, the isothermal compressibility, the Grueneisen parameter, and the speed of sound are calculated. We find that the onset of dissociation and ionization of hydrogen at about 0.9 Jupiter radii marks a region where the material properties change drastically. In the deep interior, where the electrons are degenerate, many of the material properties remain relatively constant. Our ab initio data will serve as a robust foundation for applications that require accurate knowledge of the material properties in Jupiter's interior, e.g., models for the dynamo generation.

French, Martin; Becker, Andreas; Lorenzen, Winfried; Nettelmann, Nadine; Bethkenhagen, Mandy; Redmer, Ronald [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Wicht, Johannes [Max-Planck-Institut fuer Sonnensystemforschung, D-37191 Katlenburg-Lindau (Germany)

2012-09-15T23:59:59.000Z

460

Infrared Behavior of Scalar Condensates in Effective Holographic Theories  

E-Print Network (OSTI)

We investigate the infrared behavior of the spectrum of scalar-dressed, asymptotically Anti de Sitter (AdS) black brane (BB) solutions of effective holographic models. These solutions describe scalar condensates in the dual field theories. We show that for zero charge density the ground state of these BBs must be degenerate with the AdS vacuum, must satisfy conformal boundary conditions for the scalar field and it is isolated from the continuous part of the spectrum. When a finite charge density is switched on, the ground state is not anymore isolated and the degeneracy is removed. Depending on the coupling functions, the new ground state may possibly be energetically preferred with respect to the extremal Reissner-Nordstrom AdS BB. We derive several properties of BBs near extremality and at finite temperature. As a check and illustration of our results we derive and discuss several analytic and numerical, BB solutions of Einstein-scalar-Maxwell AdS gravity with different coupling functions and different potentials. We also discuss how our results can be used for understanding holographic quantum critical points, in particular their stability and the associated quantum phase transitions leading to superconductivity or hyperscaling violation.

Mariano Cadoni; Paolo Pani; Matteo Serra

2013-04-11T23:59:59.000Z

Note: This page contains sample records for the topic "age-related macular degeneration" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Supersymmetric Custodial Triplets  

E-Print Network (OSTI)

We analyze the extension of the Minimal Supersymmetric Standard Model which includes extra Y=(0,\\pm 1) supersymmetric triplets with a global SU(2)_L \\otimes SU(2)_R symmetry spontaneousy broken to the custodial SU(2)_V by the vacuum expectation value of the neutral scalar components of doublets and triplets. The model is the supersymmetrization of the non-supersymmetric model introduced long ago by Georgi and Machacek where the \\rho-parameter is kept to unity at the tree-level by the custodial symmetry. Accordingly the scalar sector is classified into degenerate SU(2)_V multiplets: singlets, triplets (including the one containing the Godstone bosons) and fiveplets. The singly and doubly charged chiral superfields play a key role in the unitarization of the theory. The couplings of the Standard Model-like Higgs to vector bosons (including \\gamma\\gamma) and fermions, and the corresponding Higgs signal strengths, are in agreement with LHC experimental data for a large region of the parameter space. Breaking of custodial invariance by radiative corrections suggests a low-scale mechanism of supersymmetry breaking.

Luis Cort; Mateo Garcia; Mariano Quiros

2013-08-19T23:59:59.000Z

462

Dynamical polarization in pionic atoms  

SciTech Connect

Dynamical nuclear polarization occurs in pionic atoms when a nuclear excitation of appropriate multipolarity is nearly degenerate with de-excitation of a pion atomic level. This phenomenon has been studied in several nuclei, one goal being to test the pion optical potential for pion atomic states normally ''hidden'' because of pion absorption. We find that, in addition to Coulomb mixing of the atomic and nuclear levels, strong interaction mixing and nuclear excitations above the lowest collective quadrupole mode are important for understanding the experimental results. All cases except /sup 110/Pd can then be understood. For /sup 110/Pd, additional nuclear structure information is needed to determine whether or not the conventional pion optical potential will suffice again. We discuss the sensitivity of dynamical polarization measurements to the parameters of the optical potential and to various aspects of nuclear structure. In particular, we find that pionic /sup 150/Sm provides a test of the interacting boson model and that the difference in neutron and proton radii predicted by Hartree-Fock calculations affects the mixing appreciably.

Dubach, J.F.; Moniz, E.J.; Nixon, G.D.

1979-08-01T23:59:59.000Z

463

Photonic circuits for generating modal, spectral, and polarization entanglement  

E-Print Network (OSTI)

We consider the design of photonic circuits that make use of Ti:LiNbO$_{3}$ diffused channel waveguides for generating photons with various combinations of modal, spectral, and polarization entanglement. Down-converted photon pairs are generated via spontaneous optical parametric down-conversion (SPDC) in a two-mode waveguide. We study a class of photonic circuits comprising: 1) a nonlinear periodically poled two-mode waveguide structure, 2) a set of single-mode and two-mode waveguide-based couplers arranged in such a way that they suitably separate the three photons comprising the SPDC process, and, for some applications, 3) a holographic Bragg grating that acts as a dichroic reflector. The first circuit produces frequency-degenerate down-converted photons, each with even spatial parity, in two separate single-mode waveguides. Changing the parameters of the elements allows this same circuit to produce two nondegenerate down-converted photons that are entangled in frequency or simultaneously entangled in frequency and polarization. The second photonic circuit is designed to produce modal entanglement by distinguishing the photons on the basis of their frequencies. A modified version of this circuit can be used to generate photons that are doubly entangled in mode number and polarization. The third photonic circuit is designed to manage dispersion by converting modal, spectral, and polarization entanglement into path entanglement.

Mohammed F. Saleh; Giovanni Di Giuseppe; Bahaa E. A. Saleh; Malvin Carl Teich

2010-07-19T23:59:59.000Z

464

The origins of Causality Violations in Force Free Simulations of Black Hole Magnetospheres  

E-Print Network (OSTI)

Recent simulations of force-free, degenerate (ffde) black hole magnetospheres indicate that the fast mode radiated from (or near) the event horizon can modify