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1

Publications  

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

Greg Leventis [Clear All Filters] Greg Leventis [Clear All Filters] 2013 de la Rue du Can, Stephane, Virginie E. Letschert, Greg Leventis, Theo Covary, and Xiaohua Xia. Energy Efficiency Country Study: Republic Of South Africa. Lawrence Berkeley National Laboratory, 2013. de la du Can, Stephane Rue, Amol Phadke, Greg Leventis, and Anand R. Gopal. A Global Review of Incentive Programs to Accelerate Energy-Efficient Appliances and Equipment., 2013. Leventis, Greg, Anand R. Gopal, Stephane Rue de la du Can, and Amol Phadke. Avoided Electricity Subsidy Payments Can Finance Substantial Appliance Efficiency Incentive Programs: Case Study of Mexico., 2013. de la du Can, Stephane Rue, Virginie E. Letschert, Greg Leventis, Theo Covary, and Xiaohua Xia. Energy Efficiency Country Study: Republic Of South

2

Radiance Covariance and Climate Models  

Science Conference Proceedings (OSTI)

Spectral empirical orthogonal functions (EOFs) derived from the covariance of satellite radiance spectra may be interpreted in terms of the vertical distribution of the covariance of temperature, water vapor, and clouds. This has been done for ...

Robert Haskins; Richard Goody; Luke Chen

1999-05-01T23:59:59.000Z

3

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

4

Covariant Macroscopic Quantum Geometry  

E-Print Network (OSTI)

A covariant noncommutative algebra of position operators is presented, and interpreted as the macroscopic limit of a geometry that describes a collective quantum behavior of the positions of massive bodies in a flat emergent space-time. The commutator defines a quantum-geometrical relationship between world lines that depends on their separation and relative velocity, but on no other property of the bodies, and leads to a transverse uncertainty of the geometrical wave function that increases with separation. The number of geometrical degrees of freedom in a space-time volume scales holographically, as the surface area in Planck units. Ongoing branching of the wave function causes fluctuations in transverse position, shared coherently among bodies with similar trajectories. The theory can be tested using appropriately configured Michelson interferometers.

Hogan, Craig J

2012-01-01T23:59:59.000Z

5

LATOR Covariance Analysis  

E-Print Network (OSTI)

We present results from a covariance study for the proposed Laser Astrometric Test of Relativity (LATOR) mission. This mission would send two laser-transmitter spacecraft behind the Sun and measure the relative gravitational light bending of their signals using a hundred-meter-baseline optical interferometer to be constructed on the International Space Station. We assume that each spacecraft is equipped with a $ system and assume approximately one year of data. We conclude that the observations allow a simultaneous determination of the orbit parameters of the spacecraft and of the Parametrized Post-Newtonian (PPN) parameter $\\gamma$ with an uncertainty of $2.4 \\times 10^{-9}$. We also find a $6 \\times 10^{-9}$ determination of the solar quadrupole moment, $J_2$, as well as the first measurement of the second-order post-PPN parameter $\\delta$ to an accuracy of about $10^{-3}$.

Joseph E. Plowman; Ronald W. Hellings

2005-05-12T23:59:59.000Z

6

Covariant Closed String Coherent States  

Science Conference Proceedings (OSTI)

We give the first construction of covariant coherent closed string states, which may be identified with fundamental cosmic strings. We outline the requirements for a string state to describe a cosmic string, and provide an explicit and simple map that relates three different descriptions: classical strings, light cone gauge quantum states, and covariant vertex operators. The resulting coherent state vertex operators have a classical interpretation and are in one-to-one correspondence with arbitrary classical closed string loops.

Hindmarsh, Mark; Skliros, Dimitri [Department of Physics and Astronomy, University of Sussex, Brighton, East Sussex BN1 9QH (United Kingdom)

2011-02-25T23:59:59.000Z

7

Phase-Covariant Quantum Benchmarks  

E-Print Network (OSTI)

We give a quantum benchmark for teleportation and quantum storage experiments suited for pure and mixed test states. The benchmark is based on the average fidelity over a family of phase-covariant states and certifies that an experiment can not be emulated by a classical setup, i.e., by a measure-and-prepare scheme. We give an analytical solution for qubits, which shows important differences with standard state estimation approach, and compute the value of the benchmark for coherent and squeezed states, both pure and mixed.

Calsamiglia, J; Muñoz-Tàpia, R; Bagán, E

2008-01-01T23:59:59.000Z

8

Phase-Covariant Quantum Benchmarks  

E-Print Network (OSTI)

We give a quantum benchmark for teleportation and quantum storage experiments suited for pure and mixed test states. The benchmark is based on the average fidelity over a family of phase-covariant states and certifies that an experiment can not be emulated by a classical setup, i.e., by a measure-and-prepare scheme. We give an analytical solution for qubits, which shows important differences with standard state estimation approach, and compute the value of the benchmark for coherent and squeezed states, both pure and mixed.

J. Calsamiglia; M. Aspachs; R. Munoz-Tapia; E. Bagan

2008-07-31T23:59:59.000Z

9

Sparse Covariance Selection via Robust Maximum Likelihood ...  

E-Print Network (OSTI)

Jun 8, 2005 ... Consider a data set with n variables, drawn from a multivariate Gaussian distribution N(0, ?), where the covariance matrix ? is unknown.

10

Statistical Timing Analysis using Levelized Covariance Propagation  

Science Conference Proceedings (OSTI)

Variability in process parameters is making accurate timing analysis of nano-scale integrated circuits an extremely challenging task. In this paper, we propose a new algorithm for statistical timing analysis using Levelized Covariance Propagation (LCP). ...

Kunhyuk Kang; Bipul C. Paul; Kaushik Roy

2005-03-01T23:59:59.000Z

11

Hyperspectral detection algorithms: Use covariances or subspaces?  

E-Print Network (OSTI)

There are two broad classes of hyperspectral detection algorithms.1, 2 Algorithms in the first class use the spectral covariance matrix of the background clutter; in contrast, algorithms in the second class characterize ...

Manolakis, Dimitris G.

12

Lorentz covariance of loop quantum gravity  

SciTech Connect

The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the projected spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are precisely in K on the boundary. This clarifies how the SL(2,C) spinfoam formalism yields an SU(2) theory on the boundary. These structures define a tidy Lorentz-covariant formalism for loop gravity.

Rovelli, Carlo; Speziale, Simone [Centre de Physique Theorique de Luminy, Case 907, F-13288 Marseille (France)

2011-05-15T23:59:59.000Z

13

The virtual observatory service TheoSSA: Establishing a database of synthetic stellar flux standards. I. NLTE spectral analysis of the DA-type white dwarf G 191-B2B  

E-Print Network (OSTI)

H-rich, DA-type white dwarfs are particularly suited as primary standard stars for flux calibration. State-of-the-art NLTE models consider opacities of species up to trans-iron elements and provide reliable synthetic stellar-atmosphere spectra to compare with observation. We establish a database of theoretical spectra of stellar flux standards that are easily accessible via a web interface. In the framework of the Virtual Observatory, the German Astrophysical Virtual Observatory developed the registered service TheoSSA. It provides easy access to stellar spectral energy distributions (SEDs) and is intended to ingest SEDs calculated by any model-atmosphere code. In case of the DA white dwarf G 191-B2B, we demonstrate that the model reproduces not only its overall continuum shape but also the numerous metal lines exhibited in its ultraviolet spectrum. TheoSSA is in operation and contains presently a variety of SEDs for DA white dwarfs. It will be extended in the near future and can host SEDs of all primary and ...

Rauch, T; Kruk, J W; Werner, K

2013-01-01T23:59:59.000Z

14

Spatial Morphological Covariance Applied to Texture Classification  

E-Print Network (OSTI)

of the sum of pixel values, i.e. "volume" of its input. In this paper, we investigate the potential of this operator. The image "volume", i.e. sum of pixel values, for increasing distances between the points of alternative measures to volume, and extend the work of Wilkinson (ICPR'02) in order to obtain a new covariance

Lefèvre, Sébastien

15

Covariance Localization with the Diffusion-Based Correlation Models  

Science Conference Proceedings (OSTI)

Improving the performance of ensemble filters applied to models with many state variables requires regularization of the covariance estimates by localizing the impact of observations on state variables. A covariance localization technique based on ...

Max Yaremchuk; Dmitry Nechaev

2013-02-01T23:59:59.000Z

16

Vertical Covariance Localization for Satellite Radiances in Ensemble Kalman Filters  

Science Conference Proceedings (OSTI)

A widely used observation space covariance localization method is shown to adversely affect satellite radiance assimilation in ensemble Kalman filters (EnKFs) when compared to model space covariance localization. The two principal problems are ...

William F. Campbell; Craig H. Bishop; Daniel Hodyss

2010-01-01T23:59:59.000Z

17

Dynamics of Short-Term Univariate Forecast Error Covariances  

Science Conference Proceedings (OSTI)

The covariance equation based on second-order closure for dynamics governed by a general scalar nonlinear partial differential equation (PDE) is studied. If the governing dynamics involve n space dimensions, then the covariance equation is a PDE ...

Stephen E. Cohn

1993-11-01T23:59:59.000Z

18

Nuclear fission in covariant density functional theory  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to microscopic description of nuclear fission with main emphasis on superheavy nuclei (SHN) is reviewed. The softness of SHN in the triaxial plane leads to an emergence of several competing fission pathes in the region of the inner fission barrier in some of these nuclei. The outer fission barriers of SHN are considerably affected both by triaxiality and octupole deformation.

A. V. Afanasjev; H. Abusara; P. Ring

2013-09-12T23:59:59.000Z

19

Twisted covariant noncommutative self-dual gravity  

Science Conference Proceedings (OSTI)

A twisted covariant formulation of noncommutative self-dual gravity is presented. The formulation for constructing twisted noncommutative Yang-Mills theories is used. It is shown that the noncommutative torsion is solved at any order of the {theta} expansion in terms of the tetrad and some extra fields of the theory. In the process the first order expansion in {theta} for the Plebanski action is explicitly obtained.

Estrada-Jimenez, S.; Garcia-Compean, H.; Obregon, O.; Ramirez, C. [Centro de Estudios en Fisica y Matematicas Basicas y Aplicadas, Universidad Autonoma de Chiapas, Calle 4 Oriente Norte 1428, Tuxtla Gutierrez, Chiapas (Mexico); Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, P.O. Box 14-740, 07000 Mexico D.F. (Mexico); Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Monterrey, PIIT, Via del Conocimiento 201, Autopista nueva al Aeropuerto km 9.5, 66600, Apodaca Nuevo Leon (Mexico); Instituto de Fisica de la Universidad de Guanajuato, P.O. Box E-143, 37150, Leon Gto. (Mexico); Facultad de Ciencias Fisico Matematicas, Universidad Autonoma de Puebla, P.O. Box 1364, 72000, Puebla (Mexico)

2008-12-15T23:59:59.000Z

20

Decoherence rates for Galilean covariant dynamics  

E-Print Network (OSTI)

We introduce a measure of decoherence for a class of density operators. For Gaussian density operators in dimension one it coincides with an index used by Morikawa (1990). Spatial decoherence rates are derived for three large classes of the Galilean covariant quantum semigroups introduced by Holevo. We also characterize the relaxation to a Gaussian state for these dynamics and give a theorem for the convergence of the Wigner function to the probability distribution of the classical analog of the process.

Jeremy Clark

2007-10-08T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Development of covariance capabilities in EMPIRE code  

SciTech Connect

The nuclear reaction code EMPIRE has been extended to provide evaluation capabilities for neutron cross section covariances in the thermal, resolved resonance, unresolved resonance and fast neutron regions. The Atlas of Neutron Resonances by Mughabghab is used as a primary source of information on uncertainties at low energies. Care is taken to ensure consistency among the resonance parameter uncertainties and those for thermal cross sections. The resulting resonance parameter covariances are formatted in the ENDF-6 File 32. In the fast neutron range our methodology is based on model calculations with the code EMPIRE combined with experimental data through several available approaches. The model-based covariances can be obtained using deterministic (Kalman) or stochastic (Monte Carlo) propagation of model parameter uncertainties. We show that these two procedures yield comparable results. The Kalman filter and/or the generalized least square fitting procedures are employed to incorporate experimental information. We compare the two approaches analyzing results for the major reaction channels on {sup 89}Y. We also discuss a long-standing issue of unreasonably low uncertainties and link it to the rigidity of the model.

Herman,M.; Pigni, M.T.; Oblozinsky, P.; Mughabghab, S.F.; Mattoon, C.M.; Capote, R.; Cho, Young-Sik; Trkov, A.

2008-06-24T23:59:59.000Z

22

Non-evaluation applications for covariance matrices  

Science Conference Proceedings (OSTI)

The possibility for application of covariance matrix techniques to a variety of common research problems other than formal data evaluation are demonstrated by means of several examples. These examples deal with such matters as fitting spectral data, deriving uncertainty estimates for results calculated from experimental data, obtaining the best values for plurally-measured quantities, and methods for analysis of cross section errors based on properties of the experiment. The examples deal with realistic situations encountered in the laboratory, and they are treated in sufficient detail to enable a careful reader to extrapolate the methods to related problems.

Smith, D.L.

1982-05-01T23:59:59.000Z

23

Impact of the 235U Covariance Data in Benchmark Calculations  

SciTech Connect

The error estimation for calculated quantities relies on nuclear data uncertainty information available in the basic nuclear data libraries such as the U.S. Evaluated Nuclear Data File (ENDF/B). The uncertainty files (covariance matrices) in the ENDF/B library are generally obtained from analysis of experimental data. In the resonance region, the computer code SAMMY is used for analyses of experimental data and generation of resonance parameters. In addition to resonance parameters evaluation, SAMMY also generates resonance parameter covariance matrices (RPCM). SAMMY uses the generalized least-squares formalism (Bayes method) together with the resonance formalism (R-matrix theory) for analysis of experimental data. Two approaches are available for creation of resonance-parameter covariance data. (1) During the data-evaluation process, SAMMY generates both a set of resonance parameters that fit the experimental data and the associated resonance-parameter covariance matrix. (2) For existing resonance-parameter evaluations for which no resonance-parameter covariance data are available, SAMMY can retroactively create a resonance-parameter covariance matrix. The retroactive method was used to generate covariance data for 235U. The resulting 235U covariance matrix was then used as input to the PUFF-IV code, which processed the covariance data into multigroup form, and to the TSUNAMI code, which calculated the uncertainty in the multiplication factor due to uncertainty in the experimental cross sections. The objective of this work is to demonstrate the use of the 235U covariance data in calculations of critical benchmark systems.

Leal, Luiz C [ORNL; Mueller, Don [ORNL; Arbanas, Goran [ORNL; Wiarda, Dorothea [ORNL; Derrien, Herve [ORNL

2008-01-01T23:59:59.000Z

24

AFCI-2.0 Library of Neutron Cross Section Covariances  

SciTech Connect

Neutron cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The primary purpose of the library is to provide covariances for the Advanced Fuel Cycle Initiative (AFCI) data adjustment project, which is focusing on the needs of fast advanced burner reactors. The covariances refer to central values given in the 2006 release of the U.S. neutron evaluated library ENDF/B-VII. The preliminary version (AFCI-2.0beta) has been completed in October 2010 and made available to the users for comments. In the final 2.0 release, covariances for a few materials were updated, in particular new LANL evaluations for {sup 238,240}Pu and {sup 241}Am were adopted. BNL was responsible for covariances for structural materials and fission products, management of the library and coordination of the work, while LANL was in charge of covariances for light nuclei and for actinides.

Herman, M.; Herman,M.; Oblozinsky,P.; Mattoon,C.; Pigni,M.; Hoblit,S.; Mughabghab,S.F.; Sonzogni,A.; Talou,P.; Chadwick,M.B.; Hale.G.M.; Kahler,A.C.; Kawano,T.; Little,R.C.; Young,P.G.

2011-06-26T23:59:59.000Z

25

On the definition of the covariant lattice Dirac operator  

E-Print Network (OSTI)

In the continuum the definitions of the covariant Dirac operator and of the gauge covariant derivative operator are tightly intertwined. We point out that the naive discretization of the gauge covariant derivative operator is related to the existence of local unitary operators which allow the definition of a natural lattice gauge covariant derivative. The associated lattice Dirac operator has all the properties of the classical continuum Dirac operator, in particular antihermiticy and chiral invariance in the massless limit, but is of course non-local in accordance to the Nielsen-Ninomiya theorem. We show that this lattice Dirac operator coincides in the limit of an infinite lattice volume with the naive gauge covariant generalization of the SLAC derivative, but contains non-trivial boundary terms for finite-size lattices. Its numerical complexity compares pretty well on finite lattices with smeared lattice Dirac operators.

Claude Roiesnel

2012-11-08T23:59:59.000Z

26

Correcting eddy-covariance flux underestimates over a grassland.  

Science Conference Proceedings (OSTI)

Independent measurements of the major energy balance flux components are not often consistent with the principle of conservation of energy. This is referred to as a lack of closure of the surface energy balance. Most results in the literature have shown the sum of sensible and latent heat fluxes measured by eddy covariance to be less than the difference between net radiation and soil heat fluxes. This under-measurement of sensible and latent heat fluxes by eddy-covariance instruments has occurred in numerous field experiments and among many different manufacturers of instruments. Four eddy-covariance systems consisting of the same models of instruments were set up side-by-side during the Southern Great Plains 1997 Hydrology Experiment and all systems under-measured fluxes by similar amounts. One of these eddy-covariance systems was collocated with three other types of eddy-covariance systems at different sites; all of these systems under-measured the sensible and latent-heat fluxes. The net radiometers and soil heat flux plates used in conjunction with the eddy-covariance systems were calibrated independently and measurements of net radiation and soil heat flux showed little scatter for various sites. The 10% absolute uncertainty in available energy measurements was considerably smaller than the systematic closure problem in the surface energy budget, which varied from 10 to 30%. When available-energy measurement errors are known and modest, eddy-covariance measurements of sensible and latent heat fluxes should be adjusted for closure. Although the preferred method of energy balance closure is to maintain the Bowen-ratio, the method for obtaining closure appears to be less important than assuring that eddy-covariance measurements are consistent with conservation of energy. Based on numerous measurements over a sorghum canopy, carbon dioxide fluxes, which are measured by eddy covariance, are underestimated by the same factor as eddy covariance evaporation measurements when energy balance closure is not achieved.

Twine, T. E.; Kustas, W. P.; Norman, J. M.; Cook, D. R.; Houser, P. R.; Meyers, T. P.; Prueger, J. H.; Starks, P. J.; Wesely, M. L.; Environmental Research; Univ. of Wisconsin at Madison; DOE; National Aeronautics and Space Administration; National Oceanic and Atmospheric Administrationoratory

2000-06-08T23:59:59.000Z

27

Efficient Ensemble Covariance Localization in Variational Data Assimilation  

Science Conference Proceedings (OSTI)

Previous descriptions of how localized ensemble covariances can be incorporated into variational (VAR) data assimilation (DA) schemes provide few clues as to how this might be done in an efficient way. This article serves to remedy this hiatus in ...

Craig H. Bishop; Daniel Hodyss; Peter Steinle; Holly Sims; Adam M. Clayton; Andrew C. Lorenc; Dale M. Barker; Mark Buehner

2011-02-01T23:59:59.000Z

28

Determining Meaningful Differences for SMACEX Eddy Covariance Measurements  

Science Conference Proceedings (OSTI)

Two eddy covariance instrument comparison studies were conducted before and after the Soil Moisture–Atmosphere Coupling Experiment (SMACEX) field campaign to 1) determine if observations from multiple sensors were equivalent for the measured ...

D. W. Meek; J. H. Prueger; W. P. Kustas; J. L. Hatfield

2005-12-01T23:59:59.000Z

29

Analysis of Inadvertent Microprocessor Lag Time on Eddy Covariance Results  

Science Conference Proceedings (OSTI)

Researchers using the eddy covariance approach to measuring trace gas fluxes are often hoping to measure carbon dioxide and energy fluxes for ecosystem intercomparisons. This paper demonstrates a systematic microprocessor-caused lag of ?0.1 to ?...

Karl Zeller; Gary Zimmerman; Ted Hehn; Evgeny Donev; Diane Denny; Jeff Welker

2001-09-01T23:59:59.000Z

30

Low-Fidelity Covariances: Neutron Cross Section Covariance Estimates for 387 Materials  

DOE Data Explorer (OSTI)

"Covariance data are provided for radiative capture (or (n,ch.p.) for light nuclei), elastic scattering (or total for some actinides), inelastic scattering, (n,2n) reactions, fission and nubars over the energy range from 10(-5{super}) eV to 20 MeV. The library contains 387 files including almost all (383 out of 393) materials of the ENDF/B-VII.0. Absent are data for (7{super})Li, (232{super})Th, (233,235,238{super})U and (239{super})Pu as well as (223,224,225,226{super})Ra, while (nat{super})Zn is replaced by (64,66,67,68,70{super})Zn."[http://www.nndc.bnl.gov/lowfi/index.jsp?z=7

None

31

THEO MURPHY INTERNATIONAL SCIENTIFIC MEETING ON  

E-Print Network (OSTI)

and sustainability challenge confronting this planet. In 2008, he founded Sun Catalytix, a company committed

Rambaut, Andrew

32

THEO MURPHY INTERNATIONAL SCIENTIFIC MEETING ON  

E-Print Network (OSTI)

.45 Tom Gardiner Measurements of the atmospheric water vapour continuum using a solar- pointing Fourier the Herschel space telescope Monday 13 June 2011 9.00 Welcome by Professor Sir Peter Knight, Principal of Kavli-based observations. 14.30 Discussion #12;14.45 Measurements of the atmospheric water vapour continuum using a solar

Rambaut, Andrew

33

THEO MURPHY INTERNATIONAL SCIENTIFIC MEETING ON  

E-Print Network (OSTI)

energy industry in order to try and identify lessons learned which could now be applied to the developing of the Energy and Climate Change Division (ECC) within the highly rated School of Civil Engineering and pre-industrial development in the areas of energy resources, technologies, energy efficiency

Rambaut, Andrew

34

Direct Covariance Flux Estimates from Mobile Platforms at Sea*  

Science Conference Proceedings (OSTI)

This paper describes two methods for computing direct covariance fluxes from anemometers mounted on moving platforms at sea. These methods involve the use of either a strapped-down or gyro-stabilized system that are used to compute terms that ...

J. B. Edson; A. A. Hinton; K. E. Prada; J. E. Hare; C. W. Fairall

1998-04-01T23:59:59.000Z

35

Covariance Matrix Estimation for the Cryo-EM Heterogeneity Problem  

E-Print Network (OSTI)

In cryo-electron microscopy (cryo-EM), a microscope generates a top view of a sample of randomly-oriented copies of a molecule. The cryo-EM problem is to use the resulting set of noisy 2D projection images taken at unknown directions to reconstruct the 3D structure of the molecule. In some situations, the molecule under examination exhibits structural variability, which poses a fundamental challenge in cryo-EM. The heterogeneity problem is the task of mapping the space of conformational states of a molecule. It has been previously shown that the leading eigenvectors of the covariance matrix of the 3D molecules can be used to solve the heterogeneity problem. Estimating the covariance matrix is however challenging, since only projections of the molecules are observed, but not the molecules themselves. In this paper, we derive an estimator for the covariance matrix as a solution to a certain linear system. The linear operator to be inverted, which we term the tomographic covariance transform, is an important obj...

Katsevich, Gene; Singer, Amit

2013-01-01T23:59:59.000Z

36

Quantum covariance, quantum Fisher information and the uncertainty principle  

E-Print Network (OSTI)

In this paper the relation between quantum covariances and quantum Fisher informations are studied. This study is applied to generalize a recently proved uncertainty relation based on quantum Fisher information. The proof given hereconsiderably simplifies the previously proposed proofs and leads to more general inequalities.

Paolo Gibilisco; Fumio Hiai; Denes Petz

2007-12-07T23:59:59.000Z

37

Studies of the Polarimetric Covariance Matrix. Part I: Calibration Methodology  

Science Conference Proceedings (OSTI)

A procedure for calibration of the radar covariance matrix for the Colorado State University–University of Chicago–Illinois State Water Survey (CSU–CHILL) radar and S-Band Dual-Polarization Doppler Radar (S-Pol) systems is described. Two relative ...

J. C. Hubbert; V. N. Bringi; D. Brunkow

2003-05-01T23:59:59.000Z

38

Finding Boundary Layer Top: Application of a Wavelet Covariance Transform to Lidar Backscatter Profiles  

Science Conference Proceedings (OSTI)

Several recent studies have utilized a Haar wavelet covariance transform to provide automated detection of the boundary layer top from lidar backscatter profiles by locating the maximum in the covariance profiles. This approach is effective where ...

Ian M. Brooks

2003-08-01T23:59:59.000Z

39

A complete minimal system of covariants for the binary form of degree 7  

Science Conference Proceedings (OSTI)

A minimal system of 147 homogeneous generators of the algebra of covariants for the binary form of degree 7 is calculated. Keywords: Classical invariant theory, Covariants of binary form, Derivations

Leonid Bedratyuk

2009-02-01T23:59:59.000Z

40

Multivariate Error Covariance Estimates by Monte Carlo Simulation for Assimilation Studies in the Pacific Ocean  

Science Conference Proceedings (OSTI)

One of the most difficult aspects of ocean-state estimation is the prescription of the model forecast error covariances. The paucity of ocean observations limits our ability to estimate the covariance structures from model–observation ...

Anna Borovikov; Michele M. Rienecker; Christian L. Keppenne; Gregory C. Johnson

2005-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Lyman Alpha Flux Power Spectrum and Its Covariance  

E-Print Network (OSTI)

We analyze the flux power spectrum and its covariance using simulated Lyman alpha forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques fail at low redshift because they are insufficient for characterizing some components of the low-redshift intergalactic medium, notably the warm-hot intergalactic medium. Hence, to use the low-redshift Lyman alpha flux power spectrum to constrain cosmology, one would need realistic hydrodynamical simulations. By comparing one-dimensional mass statistics with flux statistics, we show that the nonlinear transform between density and flux quenches the fluctuations so that the flux power spectrum is much less sensitive to cosmological parameters than the one-dimensional mass power spectrum. The covariance of the flux power spectrum is nearly Gaussian. As such, the uncertainties of the underlying mass power spectrum could still be large, even though the flux power spectrum can be p...

Zhan, H; Eisenstein, D J; Katz, N; Zhan, Hu; Dave, Romeel; Eisenstein, Daniel; Katz, Neal

2005-01-01T23:59:59.000Z

42

The Covariant Electromagnetic Casimir Effect for Real Conducting Cylindrical Shells  

E-Print Network (OSTI)

Using covariant quantization of the electromagnetic field, the Casimir force per unit area experienced by a long conducting cylindrical shell, under both Dirichlet and Neumann boundary conditions, is calculated. The renormalization procedure is based on the plasma cut-off frequency for real conductors. The real case of a gold (silver) cylindrical shell is considered and the corresponding electromagnetic Casimir pressure is computed. It is discussed that the Dirichlet and Neumann problems should be considered separately without adding their corresponding results.

H. Razmi; N. Fadaei

2013-07-31T23:59:59.000Z

43

SO(3) invariance and covariance in mixtures of simple bodies  

E-Print Network (OSTI)

We adapt to mixtures the procedure of invariance of external power under the action of SO(3) to deduce balance equations. The two classical axioms about the growths of momentum and moment of momentum are derived with the help of a rule on the structure of the total power. We discuss also the covariance of the balance equations of each constituent and the nature of the constituent stress.

Paolo Maria Mariano

2004-06-24T23:59:59.000Z

44

The Polarized TMDs in the covariant parton model approach  

SciTech Connect

We derive relations between polarized transverse momentum dependent distribution functions (TMDs) and the usual parton distribution functions (PDFs) in the 3D covariant parton model, which follow from Lorentz invariance and the assumption of a rotationally symmetric distribution of parton momenta in the nucleon rest frame. Using the known PDF $g_{1}^{q}(x)$ as input we predict the $x$- and $\\mathbf{p}_{T}$-dependence of all polarized twist-2 naively time-reversal even (T-even) TMDs.

A.V. Efremov, P. Schweitzer, O.V. Teryaev, P. Zavada

2011-05-01T23:59:59.000Z

45

Lyman Alpha Flux Power Spectrum and Its Covariance  

E-Print Network (OSTI)

We analyze the flux power spectrum and its covariance using simulated Lyman alpha forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques fail at low redshift because they are insufficient for characterizing some components of the low-redshift intergalactic medium, notably the warm-hot intergalactic medium. Hence, to use the low-redshift Lyman alpha flux power spectrum to constrain cosmology, one would need realistic hydrodynamical simulations. By comparing one-dimensional mass statistics with flux statistics, we show that the nonlinear transform between density and flux quenches the fluctuations so that the flux power spectrum is much less sensitive to cosmological parameters than the one-dimensional mass power spectrum. The covariance of the flux power spectrum is nearly Gaussian. As such, the uncertainties of the underlying mass power spectrum could still be large, even though the flux power spectrum can be precisely determined from a small number of lines of sight.

Hu Zhan; Romeel Dave; Daniel Eisenstein; Neal Katz

2005-04-19T23:59:59.000Z

46

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain...  

Open Energy Info (EERE)

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Jump to: navigation, search GEOTHERMAL...

47

Solar Proton Burning Process Revisited within a Covariant Model Based on the Bethe-Salpeter Formalism  

E-Print Network (OSTI)

A covariant model based on the Bethe-Salpeter formalism is proposed for investigating the solar proton burning process $pp\\to De^+\

L. P. Kaptari; B. Kämpfer; E. Grosse

2000-01-14T23:59:59.000Z

48

Ensemble Statistics and Error Covariance of a Rapidly Intensifying Hurricane  

E-Print Network (OSTI)

This thesis presents an investigation of ensemble Gaussianity, the effect of non- Gaussianity on covariance structures, storm-centered data assimilation techniques, and the relationship between commonly used data assimilation variables and the underlying dynamics for the case of Hurricane Humberto. Using an Ensemble Kalman Filter (EnKF), a comparison of data assimilation results in Storm-centered and Eulerian coordinate systems is made. In addition, the extent of the non-Gaussianity of the model ensemble is investigated and quantified. The effect of this non-Gaussianity on covariance structures, which play an integral role in the EnKF data assimilation scheme, is then explored. Finally, the correlation structures calculated from a Weather Research Forecast (WRF) ensemble forecast of several state variables are investigated in order to better understand the dynamics of this rapidly intensifying cyclone. Hurricane Humberto rapidly intensified in the northwestern Gulf of Mexico from a tropical disturbance to a strong category one hurricane with 90 mph winds in 24 hours. Numerical models did not capture the intensification of Humberto well. This could be due in large part to initial condition error, which can be addressed by data assimilation schemes. Because the EnKF scheme is a linear theory developed on the assumption of the normality of the ensemble distribution, non-Gaussianity in the ensemble distribution used could affect the EnKF update. It is shown that multiple state variables do indeed show significant non-Gaussianity through an inspection of statistical moments. In addition, storm-centered data assimilation schemes present an alternative to traditional Eulerian schemes by emphasizing the centrality of the cyclone to the assimilation window. This allows for an update that is most effective in the vicinity of the storm center, which is of most concern in mesoscale events such as Humberto. Finally, the effect of non-Gaussian distributions on covariance structures is examined through data transformations of normal distributions. Various standard transformations of two Gaussian distributions are made. Skewness, kurtosis, and correlation between the two distributions are taken before and after the transformations. It can be seen that there is a relationship between a change in skewness and kurtosis and the correlation between the distributions. These effects are then taken into consideration as the dynamics contributing to the rapid intensification of Humberto are explored through correlation structures.

Rigney, Matthew C.

2009-05-01T23:59:59.000Z

49

Magnetohydrodynamics in stationary and axisymmetric spacetimes: A fully covariant approach  

Science Conference Proceedings (OSTI)

A fully geometrical treatment of general relativistic magnetohydrodynamics is developed under the hypotheses of perfect conductivity, stationarity, and axisymmetry. The spacetime is not assumed to be circular, which allows for greater generality than the Kerr-type spacetimes usually considered in general relativistic magnetohydrodynamics. Expressing the electromagnetic field tensor solely in terms of three scalar fields related to the spacetime symmetries, we generalize previously obtained results in various directions. In particular, we present the first relativistic version of the Soloviev transfield equation, subcases of which lead to fully covariant versions of the Grad-Shafranov equation and of the Stokes equation in the hydrodynamical limit. We have also derived, as another subcase of the relativistic Soloviev equation, the equation governing magnetohydrodynamical equilibria with purely toroidal magnetic fields in stationary and axisymmetric spacetimes.

Gourgoulhon, Eric [Laboratoire Univers et Theories, UMR 8102 du CNRS, Observatoire de Paris, Universite Paris Diderot, F-92190 Meudon (France); Markakis, Charalampos [Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States); Uryu, Koji [Department of Physics, University of the Ryukyus, Senbaru, Nishihara, Okinawa 903-0213 (Japan); Eriguchi, Yoshiharu [Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, 3-8-1, 153-8902 Tokyo (Japan)

2011-05-15T23:59:59.000Z

50

Estimating the Observed Atmospheric Response to SST Anomalies: Maximum Covariance Analysis, Generalized Equilibrium Feedback Assessment, and Maximum Response Estimation  

Science Conference Proceedings (OSTI)

Three multivariate statistical methods to estimate the influence of SST or boundary forcing on the atmosphere are discussed. Lagged maximum covariance analysis (MCA) maximizes the covariance between the atmosphere and prior SST, thus favoring ...

Claude Frankignoul; Nadine Chouaib; Zhengyu Liu

2011-05-01T23:59:59.000Z

51

A covariant causal set approach to discrete quantum gravity  

E-Print Network (OSTI)

A covariant causal set (c-causet) is a causal set that is invariant under labeling. Such causets are well-behaved and have a rigid geometry that is determined by a sequence of positive integers called the shell sequence. We first consider the microscopic picture. In this picture, the vertices of a c-causet have integer labels that are unique up to a label isomorphism. This labeling enables us to define a natural metric $d(a,b)$ between time-like separated vertices $a$ and $b$. The time metric $d(a,b)$ results in a natural definition of a geodesic from $a$ to $b$. It turns out that there can be $n\\ge 1$ such geodesics. Letting $a$ be the origin (the big bang), we define the curvature $K(b)$ of $b$ to be $n-1$. Assuming that particles tend to move along geodesics, $K(b)$ gives the tendency that vertex $b$ is occupied. In this way, the mass distribution is determined by the geometry of the c-causet. We next consider the macroscopic picture which describes the growth process of c-causets. We propose that this process is governed by a quantum dynamics given by complex amplitudes. At present, these amplitudes are unknown. But if they can be found, they will determine the (approximate) geometry of the c-causet describing our particular universe. As an illustration, we present a simple example of an amplitude process that may have physical relevance. We also give a discrete analogue of Einstein's field equations.

Stan Gudder

2013-11-15T23:59:59.000Z

52

Graviton Propagator in a Covariant Massive Gravity Theory  

E-Print Network (OSTI)

We study the massive gravity theory proposed by Arkani-Hamed, Georgi and Schwartz. In this theory, the graviton becomes massive when general covariance is spontaneously broken through the introduction of a field that links two metrics, one of the which will eventually decouple. The excitation of this "link" field acts like a Goldstone boson in giving mass to the graviton. We work out the graviton and Goldstone boson propagators explicitly by means of gauge fixing terms similar to the renormalizability gauges used in gauge theories. With these propagators, we calculate the lowest order tree-level interaction between two external energy momentum tensors. The result is independent of the gauge parameter, but different from the prediction of massless gravity theory, i.e., general relativity. This difference remains even if the mass of the graviton goes to zero, in which case it gives the van Dam-Veltman-Zakharov (vDVZ) discontinuity between the propagators of a massive and massless linearized graviton. Moreover, we show that the Fierz-Pauli graviton mass term can be considered as the ``unitary gauge'' of a more general theory with an extra scalar field. We explicitly construct such a theory in which the vDVZ discontinuity arises with a graviton mass term that is different from the Fierz-Pauli mass term. This theory has a local Weyl symmetry under conformal transformations of the metric. In the case when the mass goes to zero, the Weyl summetry becomes a global symmetry. It is possible that the local Weyl symmetry will give a hint as to the form of the corresponding fully nonlinear theory having a nonzero graviton mass.

Xing Huang; Leonard Parker

2007-05-10T23:59:59.000Z

53

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain,  

Open Energy Info (EERE)

Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Six-Week Time Series Of Eddy Covariance Co2 Flux At Mammoth Mountain, California- Performance Evaluation And Role Of Meteorological Forcing Details Activities (1) Areas (1) Regions (0) Abstract: CO2 and heat fluxes were measured over a six-week period (09/08/2006 to 10/24/2006) by the eddy covariance (EC) technique at the Horseshoe Lake tree kill (HLTK), Mammoth Mountain, CA, a site with complex terrain and high, spatially heterogeneous CO2 emission rates. EC CO2 fluxes ranged from 218 to 3500 g m- 2 d- 1 (mean = 1346 g m- 2 d- 1). Using footprint modeling, EC CO2 fluxes were compared to CO2 fluxes measured by

54

Decadal Covariability of the Northern Wintertime Land Surface Temperature and Atmospheric Circulation  

Science Conference Proceedings (OSTI)

The decadal covariability of northern wintertime land surface temperature and 500-hPa geopotential anomalies is examined using the National Centers for Environmental Prediction–National Center for Atmospheric Research and the Twentieth-Century ...

B. Yu; X. L. Wang; X. B. Zhang; J. Cole; Y. Feng

2014-01-01T23:59:59.000Z

55

Tower and Aircraft Eddy Covariance Measurements of Water Vapor, Energy, and Carbon Dioxide Fluxes during SMACEX  

Science Conference Proceedings (OSTI)

A network of eddy covariance (EC) and micrometeorological flux (METFLUX) stations over corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] canopies was established as part of the Soil Moisture–Atmosphere Coupling Experiment (SMACEX) in ...

J. H. Prueger; J. L. Hatfield; T. B. Parkin; W. P. Kustas; L. E. Hipps; C. M. U. Neale; J. I. MacPherson; W. E. Eichinger; D. I. Cooper

2005-12-01T23:59:59.000Z

56

A Hybrid Background Error Covariance Model for Assimilating Glider Data into a Coastal Ocean Model  

Science Conference Proceedings (OSTI)

A hybrid background error covariance (BEC) model for three-dimensional variational data assimilation of glider data into the Navy Coastal Ocean Model (NCOM) is introduced. Similar to existing atmospheric hybrid BEC models, the proposed model ...

Max Yaremchuk; Dmitri Nechaev; Chudong Pan

2011-06-01T23:59:59.000Z

57

Fission of actinides and superheavy nuclei: covariant density functional theory perspective  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to the description of fission barriers in actinides and superheavy nuclei is reviewed. The achievements and open problems are discussed.

A. V. Afanasjev

2013-03-05T23:59:59.000Z

58

A Wavelet Approach to Representing Background Error Covariances in a Limited-Area Model  

Science Conference Proceedings (OSTI)

The use of orthogonal wavelets for the representation of background error covariances over a limited area is studied. Each wavelet function contains both information on position and information on scale: using a diagonal correlation matrix in ...

Alex Deckmyn; Loïk Berre

2005-05-01T23:59:59.000Z

59

Interpretation of the Autocovariances and Cross-Covariance from a Polarization Diversity Radar  

Science Conference Proceedings (OSTI)

A theory is presented for interpretation of the autocovariances and cross-covariance derivable from coherent polarization diversity radars. At zero lag time these quantities yield the “main” received power, the depolarization ratio, the cross-...

James I. Metcalf

1986-11-01T23:59:59.000Z

60

Evaluating Covariance Matrix Forecasts in a Value-at-Risk Framework  

E-Print Network (OSTI)

: Covariance matrix forecasts of financial asset returns are an important component of current practice in financial risk management. A wide variety of models are available for generating such forecasts. In this paper, we evaluate the relative performance of different covariance matrix forecasts using standard statistical loss functions and a value-at-risk (VaR) framework. Using a foreign exchange portfolio, we find covariance matrix forecasts generated from option prices perform best under statistical loss functions, such as mean-squared error. Within a VaR framework, the relative performance of covariance matrix forecasts depends greatly on the VaR models' distributional assumptions. Of the forecasts examined, simple specifications, such as exponentially-weighted moving averages of past observations, perform best with regard to the magnitude of VaR exceptions and regulatory capital requirements. Our results provide empirical support for the commonly-used VaR models based on simple c...

Jose A. Lopez; Christian A. Walter

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

A Study of the Error Covariance Matrix of Radar Rainfall Estimates in Stratiform Rain  

Science Conference Proceedings (OSTI)

The contribution of various physical sources of uncertainty affecting radar rainfall estimates at the ground is quantified toward deriving and understanding the error covariance matrix of these estimates. The focus here is on stratiform ...

Marc Berenguer; Isztar Zawadzki

2008-12-01T23:59:59.000Z

62

Fully Covariant Van Dam-Veltman-Zakharov Discontinuity, and Absence Thereof  

E-Print Network (OSTI)

In both old and recent literature, it has been argued that the celebrated van Dam-Veltman-Zakharov (vDVZ) discontinuity of massive gravity is an artifact due to linearization of the true equations of motion. In this letter, we investigate that claim. First, we exhibit an explicit -albeit somewhat arbitrary- fully covariant set of equations of motion that, upon linearization, reduce to the standard Pauli-Fierz equations. We show that the vDVZ discontinuity still persists in that non-linear, covariant theory. Then, we restrict our attention to a particular system that consistently incorporates massive gravity: the Dvali-Gabadadze-Porrati (DGP) model. DGP is fully covariant and does not share the arbitrariness and imperfections of our previous covariantization, and its linearization exhibits a vDVZ discontinuity. Nevertheless, we explicitly show that the discontinuity does disappear in the fully covariant theory, and we explain the reason for this phenomenon.

M. Porrati

2002-03-01T23:59:59.000Z

63

Adaptive Ensemble Covariance Localization in Ensemble 4D-VAR State Estimation  

Science Conference Proceedings (OSTI)

An adaptive ensemble covariance localization technique, previously used in “local” forms of the ensemble Kalman filter, is extended to a global ensemble four-dimensional variational data assimilation (4D-VAR) scheme. The purely adaptive part of ...

Craig H. Bishop; Daniel Hodyss

2011-04-01T23:59:59.000Z

64

Why is marsh productivity so high? New insights from eddy covariance and biomass measurements in a Typha marsh  

E-Print Network (OSTI)

Miao, S.L. , 2001. Growth, biomass allocation and nutrientfrom eddy covariance and biomass measurements in a Typhaof photosynthate to plant biomass (Amthor, 1989). This

Rocha, Adrian V.; Goulden, Michael L.

2009-01-01T23:59:59.000Z

65

Hamiltonian analysis of nonrelativistic covariant restricted-foliation-preserving diffeomorphism invariant Horava-Lifshitz gravity  

SciTech Connect

We perform the Hamiltonian analysis of nonrelativistic covariant Horava-Lifshitz gravity in the formulation presented recently in arXiv:1009.4885. We argue that the resulting Hamiltonian structure is in agreement with the original construction of nonrelativistic covariant Horava-Lifshitz gravity presented in arXiv:1007.2410. Then we extend this construction to the case of restricted-foliation-preserving diffeomorphism invariant Horava-Lifshitz theory. We find a well behaved Hamiltonian system with the number of the first- and the second-class constraints that ensure the correct number of physical degrees of freedom of gravity.

Kluson, J. [Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlarska 2, 611 37, Brno (Czech Republic)

2011-02-15T23:59:59.000Z

66

Statistical timing analysis using levelized covariance propagation considering systematic and random variations of process parameters  

Science Conference Proceedings (OSTI)

Variability in process parameters is making accurate timing analysis of nano-scale integrated circuits an extremely challenging task. In this article, we propose a new algorithm for statistical static timing analysis (SSTA) using levelized covariance ... Keywords: Process variation, spatial correlation, statistical timing analysis

Kunhyuk Kang; Bipul C. Paul; Kaushik Roy

2006-10-01T23:59:59.000Z

67

Un nouveau TCL pour les oprateurs de covariance dans le modle ARH(1).  

E-Print Network (OSTI)

Un nouveau TCL pour les opérateurs de covariance dans le modèle ARH(1). André MAS Université, nous donnons des conditions su¢ santes pour l'obtention du TCL pour la suite des opérateurs de

Mas, André

68

A Statistical Investigation of the Sensitivity of Ensemble-Based Kalman Filters to Covariance Filtering  

Science Conference Proceedings (OSTI)

This paper investigates the effects of spatial filtering on the ensemble-based estimate of the background error covariance matrix in an ensemble-based Kalman filter (EnKF). In particular, a novel kernel smoothing method with variable bandwidth is ...

Mikyoung Jun; Istvan Szunyogh; Marc G. Genton; Fuqing Zhang; Craig H. Bishop

2011-09-01T23:59:59.000Z

69

Dynamics and Structure of Forecast Error Covariance in the Core of a Developing Hurricane  

Science Conference Proceedings (OSTI)

An ensemble of cloud-resolving forecasts from the Weather Research and Forecasting model (WRF) was used to study error covariance for Hurricane Katrina (2005) during a 64-h period in which the storm progressed from a tropical storm to a category-4 ...

Jonathan Poterjoy; Fuqing Zhang

2011-08-01T23:59:59.000Z

70

Chapter 16: The Analysis of Covariance In some experiments, the experimental units are nonhomogeneous  

E-Print Network (OSTI)

and the covariate, the model can be given by yij = µi + 1(xij - ¯x..) + ij, 3 #12;Table 1: Peanut plant growth data is reduced. This will often 1 #12;result in increased precision for parameter estimates and increased power, a slow-release fertilizer (S) and a fast-release fertilizer (F), on seed yields (grams) of peanut plant

Liang, Faming

71

Covariant basis induced by parity for the $(j,0)\\oplus (0,j)$ representation  

E-Print Network (OSTI)

In this work, we build a covariant basis for operators acting on the $(j,0)\\oplus(0,j)$ Lorentz group representations. The construction is based on an analysis of the covariant properties of the parity operator, which for these representations transforms as the completely temporal component of a symmetrical tensor of rank $2j$. The covariant properties of parity involve the Jordan algebra of anti commutators of the Lorentz group generators which unlike the Lie algebra is not universal. We make the construction explicit for $j=1/2,1$ and 3/2, reproducing well-known results for the $j=1/2$ case. We provide an algorithm for the corresponding calculations for arbitrary $j$. This covariant basis provides an inventory of all the possible interaction terms for gauge and non-gauge theories of fields for these representations. In particular, it supplies a single second rank antisymmetric structure, which in the Poincar\\'e projector formalism implies a single Pauli term arising from gauge interactions and a single (free) parameter $g$, the gyromagnetic factor, which characterizes all multipoles of these fields regardless of the spin value.

Selim Gómez-Ávila; M. Napsuciale

2013-07-17T23:59:59.000Z

72

Author's personal copy Determination of Resonance Parameters and their Covariances from Neutron Induced  

E-Print Network (OSTI)

component tt. Consequently, response functions will strongly depend on the neutron physics propertiesAuthor's personal copy Determination of Resonance Parameters and their Covariances from Neutron AT A WHITE NEUTRON SOURCE 3056 A. Time-of-Flight Facilities 3056 B. Time-of-Flight Technique 3056 C. Response

Danon, Yaron

73

Classification of the Colonic Polyps in CT-Colonography Using Region Covariance as Descriptor Features of Suspicious Regions  

Science Conference Proceedings (OSTI)

We present an algorithm to classify polyps in CT colonography images utilizing covariance matrices as object descriptors. Since these descriptors do not lie on a vector space, they cannot simply be fed to traditional machine learning tools such as support ... Keywords: CT colonography, Colonic polyp detection, Covariance descriptor

Niyazi Kilic; Olcay Kursun; Osman Nuri Ucan

2010-04-01T23:59:59.000Z

74

Numerical Aspects of the Application of Recursive Filters to Variational Statistical Analysis. Part II: Spatially Inhomogeneous and Anisotropic General Covariances  

Science Conference Proceedings (OSTI)

In this second part of a two-part study of recursive filter techniques applied to the synthesis of covariances in a variational analysis, methods by which non-Gaussian shapes and spatial inhomogeneities and anisotropies for the covariances may be ...

R. James Purser; Wan-Shu Wu; David F. Parrish; Nigel M. Roberts

2003-08-01T23:59:59.000Z

75

Separation of correlated astrophysical sources using multiple-lag data covariance matrices  

E-Print Network (OSTI)

This paper deals with a source separation strategy based on second-order statistics, namely, on data covariance matrices estimated at several lags. In general, ``blind'' approaches to source separation do not assume any knowledge on the mixing operator; however, any prior information about the possible structure of the mixing operator can improve the solution. Unlike ICA blind separation approaches, where mutual independence between the sources is assumed, our method only needs to constrain second-order statistics, and is effective even if the original sources are significantly correlated. Besides the mixing matrix, our strategy is also capable to evaluate the source covariance functions at several lags. Moreover, once the mixing parameters have been identified, a simple deconvolution can be used to estimate the probability density functions of the source processes. To benchmark our algorithm, we used a database that simulates the one expected from the instruments that will operate onboard ESA's Planck Survey...

Bedini, L; Salerno, E; Baccigalupi, C; Kuruouglu, E E; Tonazzini, A

2004-01-01T23:59:59.000Z

76

On the covariant gauge {alpha} of the linearized gravity in de Sitter spacetime  

SciTech Connect

In previous work, we studied the linearized gravity with covariant gauge {beta}= 2/3 and {alpha}= 5/3. It was found that the sum of the source and initial contributions reproduces the correct field configuration over the whole de Sitter spacetime. In this paper, we extend this work to generalizing the linearized gravitational field in an arbitrary value of the gauge parameter {alpha} but the gauge parameter {beta} remains the same.

Cheong, Lee Yen [Department of Fundamental and Applied Science Universiti Teknologi Petronas, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

2012-09-26T23:59:59.000Z

77

Covariant Density Functional Theory--highlights on recent progress and applications  

SciTech Connect

The density functional theory with a few number of parameters allows a very successful phenomenological description of ground state properties of nuclei all over the nuclear chart. The recent progress on the application of the covariant density functional theory (CDFT) for nuclear structure and astrophysics as well as its extensions by the group in Beijing is summarized. In particular, its application to magnetic moments is discussed in details.

Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Li, J.; Zhao, P. W.; Liang, H. Z. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Yao, J. M. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)

2011-05-06T23:59:59.000Z

78

Fission barriers in actinides in covariant density functional theory: the role of triaxiality  

E-Print Network (OSTI)

Relativistic mean field theory allowing for triaxial deformations is applied for a systematic study of fission barriers in the actinide region. Different pairing schemes are studied in details and it is shown that covariant density functional theory is able to describe fission barriers on a level of accuracy comparable with non-relativistic calculations, even with the best phenomenological macroscopic+microscopic approaches. Triaxiality in the region of the first saddle plays a crucial role in achieving that.

H. Abusara; A. V. Afanasjev; P. Ring

2010-10-09T23:59:59.000Z

79

ORNL Resolved Resonance Covariance Generation for ENDF/B-VII.1  

SciTech Connect

Resonance-parameter covariance matrix (RPCM) evaluations in the resolved resonance regionwere done at the Oak Ridge National Laboratory (ORNL) for the chromium isotopes, titanium isotopes, {sup 19}F, {sup 58}Ni, {sup 60}Ni, {sup 35}Cl, {sup 37}Cl, {sup 39}K, {sup 41}K, {sup 55}Mn, {sup 233}U, {sup 235}U, {sup 238}U, and {sup 239}Pu using the computer code SAMMY. The retroactive approach of the code SAMMY was used to generate the RPCMs for {sup 233}U. For {sup 235}U, the approach used for covariance generation was similar to the retroactive approach with the distinction that real experimental data were used as opposed to data generated from the resonance parameters. RPCMs for {sup 238}U and {sup 239}Pu were generated together with the resonance parameter evaluations. The RPCMs were then converted in the ENDF format using the FILE32 representation. Alternatively, for computer storage reasons, the FILE32 was converted in the FILE33 cross section covariance matrix (CSCM). Both representations were processed using the computer code PUFF-IV. This paper describes the procedures used to generate the RPCM and CSCM in the resonance region for ENDF/B-VII.1. The impact of data uncertainty in nuclear reactor benchmark calculations is also presented.

Leal, L. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6354 (United States)] [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6354 (United States); Guber, K.; Wiarda, D.; Arbanas, G.; Derrien, H.; Sayer, R.; Larson, N.; Dunn, M. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6354 (United States)] [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6354 (United States)

2012-12-15T23:59:59.000Z

80

Biasing of the Covariance-Based Spectral Mean Estimator in the Presence of Band-Limited Noise  

Science Conference Proceedings (OSTI)

Estimation of spectral mean frequency (spectral first moment) by the variance technique is considered for a signal process contaminated by band limited, additive noise. It is shown that the covariance-based spectral mean estimator is biased for ...

Albert J. Plueddemann; Robert Pinkel

1991-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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.


81

The Gaussian Approach to Adaptive Covariance Inflation and Its Implementation with the Local Ensemble Transform Kalman Filter  

Science Conference Proceedings (OSTI)

In ensemble Kalman filters, the underestimation of forecast error variance due to limited ensemble size and other sources of imperfection is commonly treated by empirical covariance inflation. To avoid manual optimization of multiplicative ...

Takemasa Miyoshi

2011-05-01T23:59:59.000Z

82

Dynamics and Structure of Mesoscale Error Covariance of a Winter Cyclone Estimated through Short-Range Ensemble Forecasts  

Science Conference Proceedings (OSTI)

Several sets of short-range mesoscale ensemble forecasts generated with different types of initial perturbations are used in this study to investigate the dynamics and structure of mesoscale error covariance in an intensive extratropical ...

Fuqing Zhang

2005-10-01T23:59:59.000Z

83

Delta and Omega electromagnetic form factors in a three-body covariant Bethe-Salpeter approach  

E-Print Network (OSTI)

The electromagnetic form factors of the Delta and Omega baryons are calculated in the framework of Poincare-covariant bound-state equations. The quark-quark interaction is truncated to a single dressed-gluon exchange where for the dressings we use two different models and compare the results. The calculation predicts an oblate shape for the electric charge distribution and a prolate shape for the magnetic dipole distribution. We also identify the necessity of including pion-cloud corrections at low photon-momentum transfer.

Helios Sanchis-Alepuz; Richard Williams; Reinhard Alkofer

2013-02-25T23:59:59.000Z

84

Covariant nucleon wave function with S, D, and P-state components  

Science Conference Proceedings (OSTI)

Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.

Franz Gross, G. Ramalho, M. T. Pena

2012-05-01T23:59:59.000Z

85

A relativistically covariant version of Bohm's quantum field theory for the scalar field  

E-Print Network (OSTI)

We give a relativistically covariant, wave-functional formulation of Bohm's quantum field theory for the scalar field based on a general foliation of space-time by space-like hypersurfaces. The wave functional, which guides the evolution of the field, is space-time-foliation independent but the field itself is not. Hence, in order to have a theory in which the field may be considered a beable, some extra rule must be given to determine the foliation. We suggest one such rule based on the eigen vectors of the energy-momentum tensor of the field itself.

George Horton; Chris Dewdney

2004-07-13T23:59:59.000Z

86

Experimental phase-covariant cloning of polarization states of single photons  

E-Print Network (OSTI)

The experimental realization of optimal symmetric phase-covariant 1->2 cloning of qubit states is presented. The qubits are represented by polarization states of photons generated by spontaneous parametric down-conversion. The experiment is based on the interference of two photons on a custom-made beam splitter with different splitting ratios for vertical and horizontal polarization components. From the measured data we have estimated the implemented cloning transformation using the maximum-likelihood method. The result shows that the realized transformation is very close to the ideal one and the map fidelity reaches 94%.

A. Cernoch; L. Bartuskova; J. Soubusta; M. Jezek; J. Fiurasek; M. Dusek

2006-07-21T23:59:59.000Z

87

Separation of correlated astrophysical sources using multiple-lag data covariance matrices  

E-Print Network (OSTI)

This paper deals with a source separation strategy based on second-order statistics, namely, on data covariance matrices estimated at several lags. In general, ``blind'' approaches to source separation do not assume any knowledge on the mixing operator; however, any prior information about the possible structure of the mixing operator can improve the solution. Unlike ICA blind separation approaches, where mutual independence between the sources is assumed, our method only needs to constrain second-order statistics, and is effective even if the original sources are significantly correlated. Besides the mixing matrix, our strategy is also capable to evaluate the source covariance functions at several lags. Moreover, once the mixing parameters have been identified, a simple deconvolution can be used to estimate the probability density functions of the source processes. To benchmark our algorithm, we used a database that simulates the one expected from the instruments that will operate onboard ESA's Planck Surveyor Satellite to measure the CMB anisotropies all over the celestial sphere. The assumption was made that the emission spectra of the galactic foregrounds can be parametrised, thus reducing the number of unknowns for system identification to the number of the foreground radiations. We performed separation in several sky patches, featuring different levels of galactic contamination to the CMB, and assuming several noise levels, including the ones derived from the Planck specifications.

L. Bedini; D. Herranz; E. Salerno; C. Baccigalupi; E. E. Kuruouglu; A. Tonazzini

2004-07-06T23:59:59.000Z

88

Separation of correlated astrophysical sources using multiple-lag data covariance matrices  

E-Print Network (OSTI)

This paper deals with a source separation strategy based on secondorder statistics, namely, on data covariance matrices estimated at several lags. In general, “blind ” approaches to source separation do not assume any knowledge on the mixing operator; however, any prior information about the possible structure of the mixing operator can improve the solution. Unlike ICA blind separation approaches, where mutual independence between the sources is assumed, our method only needs to constrain second-order statistics, and is effective even if the original sources are significantly correlated. Besides the mixing matrix, our strategy is also capable to evaluate the source covariance functions at several lags. Moreover, once the mixing parameters have been identified, a simple deconvolution can be used to estimate the probability density functions of the source processes. To benchmark our algorithm, we used a database that simulates the one expected from the instruments that will operate onboard ESA’s Planck Surveyor Satellite to measure the CMB anisotropies all over the celestial sphere. The assumption was made that the emission spectra of the galactic foregrounds can be parametrised, thus reducing the number of unknowns for system identification to the number of the foreground radiations. We performed separation in several sky patches, featuring different levels of galactic contamination to the CMB, and assuming several noise levels, including the ones derived from the Planck specifications.

L. Bedini; D. Herranz; E. Salerno; C. Baccigalupi; E. E. Kuruo?glu; A. Tonazzini

2005-01-01T23:59:59.000Z

89

Pion production in proton-proton collisions in a covariant one boson exchange model  

E-Print Network (OSTI)

Motivated by the renewed interest in studying the pion production on nuclei with protons at few GeV incident energies, we investigate the pion production in proton-proton collisions over an energy range of 300 MeV to 2 GeV. Starting from a realistic one-boson exchange model with parameters fitted to the amplitudes of the elastic nucleon-nucleon scattering, we perform fully covariant calculations for the total, double and triple differential cross-sections of the p(p,n\\pi^+)p and p(p,p\\pi^0)p reactions. The calculations incorporate the exchange of \\pi, \\rho,\\omega and \\sigma mesons and treat nucleon and delta isobar as intermediate states. We obtain a reasonably good agreement with the experimental data in the entire range of beam energies. The form of the covariant delta propagator, the cut-off parameter for the \\pi NN and \\pi N\\Delta vertex form factors and the energy dependence of the delta isobar decay width is investigated.

Engel, A; Shyam, R; Mosel, U

1996-01-01T23:59:59.000Z

90

Pion production in proton-proton collisions in a covariant one boson exchange model  

E-Print Network (OSTI)

Motivated by the renewed interest in studying the pion production on nuclei with protons at few GeV incident energies, we investigate the pion production in proton-proton collisions over an energy range of 300 $MeV$ to 2 $GeV$. Starting from a realistic one-boson exchange model with parameters fitted to the amplitudes of the elastic nucleon-nucleon scattering, we perform fully covariant calculations for the total, double and triple differential cross-sections of the $p(p,n\\pi^+)p$ and $p(p,p\\pi^0)p$ reactions. The calculations incorporate the exchange of $\\pi, \\rho,\\omega$ and $\\sigma$ mesons and treat nucleon and delta isobar as intermediate states. We obtain a reasonably good agreement with the experimental data in the entire range of beam energies. The form of the covariant delta propagator, the cut-off parameter for the $\\pi NN$ and $\\pi N\\Delta$ vertex form factors and the energy dependence of the delta isobar decay width is investigated.

A. Engel; A. K. Dutt-Mazumder; R. Shyam; U. Mosel

1996-01-18T23:59:59.000Z

91

Nuclear Data and Measurement Series - a method to construct covariance files in ENDF/B format for criticality safety applications.  

DOE Green Energy (OSTI)

Argonne National Laboratory is providing support for a criticality safety analysis project that is being performed at Oak Ridge National Laboratory. The ANL role is to provide the covariance information needed by ORNL for this project. The ENDF/B-V evaluation is being used for this particular criticality analysis. In this evaluation, covariance information for several isotopes or elements of interest to this analysis is either not given or needs to be reconsidered. For some required materials, covariance information does not exist in ENDF/B-V: {sup 233}U, {sup 236}U, Zr, Mg, Gd, and Hf. For others, existing covariance information may need to be re-examined in light of the newer ENDF/B-V evaluation and recent experimental data. In this category are the following materials: {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, {sup 241}Pu, Fe, H, C, N, O, Al, Si, and B. A reasonable estimation of the fractional errors for various evaluated neutron cross sections from ENDF/B-V can be based on the comparisons between the major more recent evaluations including ENDF/B-VI, JENDL3.2, BROND2.2, and JEF2.2, as well as a careful examination of experimental data. A reasonable method to construct correlation matrices is proposed here. Coupling both of these considerations suggests a method to construct covariances files in ENDF/B format that can be used to express uncertainties for specific ENDF/B-V cross sections.

Naberejnev, D.G.; Smith, D.L.

1999-07-30T23:59:59.000Z

92

Unified Field Theory From Enlarged Transformation Group. The Covariant Derivative for Conservative Coordinate Transformations and Local Frame Transformations  

E-Print Network (OSTI)

Pandres has developed a theory in which the geometrical structure of a real four-dimensional space-time is expressed by a real orthonormal tetrad, and the group of diffeomorphisms is replaced by a larger group called the conservation group. This paper extends the geometrical foundation for Pandres' theory by developing an appropriate covariant derivative which is covariant under all local Lorentz (frame) transformations, including complex Lorentz transformations, as well as conservative transformations. After defining this extended covariant derivative, an appropriate Lagrangian and its resulting field equations are derived. As in Pandres' theory, these field equations result in a stress-energy tensor that has terms which may automatically represent the electroweak field. Finally, the theory is extended to include 2-spinors and 4-spinors.

Edward Lee Green

2009-07-22T23:59:59.000Z

93

Eddy covariance mapping and quantification of surface CO2 leakage fluxes  

SciTech Connect

We present eddy covariance measurements of net CO{sub 2} flux (F{sub c}) made during a controlled release of CO{sub 2} (0.3 t d{sup -1} from 9 July to 7 August 2008) from a horizontal well {approx}100 m in length and {approx}2.5 m in depth located in an agricultural field in Bozeman, MT. We isolated fluxes arising from the release (F{sub cr}) by subtracting fluxes corresponding to a model for net ecosystem exchange from F{sub c}. A least-squares inversion of 611 F{sub cr} and corresponding modeled footprint functions recovered the location, length, and magnitude of the surface CO{sub 2} flux leakage signal, although high wavenumber details of the signal were poorly resolved. The estimated total surface CO{sub 2} leakage rate (0.32 t d{sup ?1}) was within 7% of the release rate.

Lewicki, J.L.; Hilley, G.E.

2009-08-01T23:59:59.000Z

94

Uncertainty estimation of core safety parameters using cross-correlations of covariance matrix  

Science Conference Proceedings (OSTI)

An uncertainty estimation method for core safety parameters, for which measurement values are not obtained, is proposed. We empirically recognize the correlations among the prediction errors among core safety parameters, e.g., a correlation between the control rod worth and assembly relative power of corresponding position. Correlations of uncertainties among core safety parameters are theoretically estimated using the covariance of cross sections and sensitivity coefficients for core parameters. The estimated correlations among core safety parameters are verified through the direct Monte-Carlo sampling method. Once the correlation of uncertainties among core safety parameters is known, we can estimate the uncertainty of a safety parameter for which measurement value is not obtained. Furthermore, the correlations can be also used for the reduction of uncertainties of core safety parameters. (authors)

Yamamoto, A.; Yasue, Y.; Endo, T. [Graduate School of Engineering, Nagoya Univ., Furo-cho, Chikusa-ku, Nagoya (Japan); Kodama, Y.; Ohoka, Y.; Tatsumi, M. [Nuclear Fuel Industries, Ltd., Asashiro-nishi, Kumatori-cho, Osaka (Japan)

2012-07-01T23:59:59.000Z

95

Covariant energy-momentum and an uncertainty principle for general relativity  

E-Print Network (OSTI)

We recognize the natural covariant extension for energy-momentum in general relativity: energy-momentum in spacetime as opposed to space. The key indicator is the Tolman energy integral for stationary systems. The demand that the general expression for arbitrary dynamic systems reduce to the Tolman integral in the case of stationarity leads to the matter-localized Ricci integral for energy-momentum in support of the energy localization hypothesis. The role of the observer is addressed and it is recognized that the field of freely-falling observers extract the global Tolman energy. It is suggested that in the extreme of strong gravity, the Heisenberg Uncertainty Principle be generalized in terms of spacetime energy-momentum.

F. I. Cooperstock; M. J. Dupre

2009-04-02T23:59:59.000Z

96

Resonance Evaluation of 48Ti Including Covariance for Criticality Safety Applications  

Science Conference Proceedings (OSTI)

In this work we report the methodology and the results of an evaluation carried out for 48Ti in the resolved resonance region for applications in criticality safety calculations. The evaluation was performed using the computer code SAMMY with the reduced R-matrix Reich-Moore formalism. The Bayes scheme was utilized for fitting the experimental data. New transmission and capture data were essential in the evaluation process. A complete set of resonance parameters was obtained in the energy region from thermal to 400 keV. In addition to the resonance parameters, a resonance parameter covariance matrix was also obtained. The impact of the new resonance parameter evaluation in benchmark calculations, as well as the uncertainty, was verified.

Leal, Luiz C [ORNL; Guber, Klaus H [ORNL; Arbanas, Goran [ORNL; Wiarda, Dorothea [ORNL; Koehler, Paul Edward [ORNL; Kahler, A. [Los Alamos National Laboratory (LANL)

2011-01-01T23:59:59.000Z

97

Major questions about derivation of variance-covariance information for nuclear data evaluations  

SciTech Connect

The uncertainties in and correlations among some evaluated nuclear data are now evaluated to permit estimation of data-related uncertainties in the outputs of neutronic calculations and to focus data improvement efforts. Questions are discussed that arise in trying to obtain adequate numerical files of variance-covariance uncertainty information. These involve (1) discrepant data, (2) experimental data with incompletely reported uncertainties, (3) uncertainties in nuclear model results, (4) uncertainty data for the resonance regions and for angle and energy distributions, and (5) the role of integral data in nuclear data evaluation. The question also arises whether files of uncertainty data designed for technological applications can suffice to represent past knowledge in an evaluation that includes new data. Directions are indicated toward resolving these questions.

Peelle, R.W.

1982-01-01T23:59:59.000Z

98

$|V_{ub}|$ and $B\\to\\eta^{(')}$ Form Factors in Covariant Light Front Approach  

E-Print Network (OSTI)

We study $B\\to (\\pi, \\eta, \\eta')$ transition form factors in the framework of covariant light front approach. With the theoretical uncertainties, we find that $B\\to (\\pi, \\eta, \\eta')$ form factors at $q^2=0$ are $f^{(\\pi, \\eta, \\eta')}_{+}(0)=(0.245^{+0.000}_{-0.001}\\pm 0.011, 0.220 \\pm 0.009\\pm0.009, 0.180\\pm 0.008^{+0.008}_{-0.007})$ for vector current and $f^{(\\pi, \\eta, \\eta')}_{T}(0)=(0.239^{+0.002+0.020}_{-0.003-0.018}, 0.211\\pm 0.009^{+0.017}_{-0.015}, 0.173\\pm 0.007^{+0.014}_{-0.013})$ for tensor current, respectively. With the obtained $q^2$-dependent $f^{\\pi}_{+}(q^2)$ and observed branching ratio (BR) for $\\bar B_d\\to \\pi^+ \\ell \\bar \

Chen, Chuan-Hung; Wang, Wei

2009-01-01T23:59:59.000Z

99

Optimal designs to select individuals for genotyping conditional on observed binary or survival outcomes and non-genetic covariates  

Science Conference Proceedings (OSTI)

In gene-disease association studies, the cost of genotyping makes it economical to use a two-stage design where only a subset of the cohort is genotyped. At the first-stage, the follow-up data along with some risk factors or non-genetic covariates are ...

Juha Karvanen; Sangita Kulathinal; Dario Gasbarra

2009-03-01T23:59:59.000Z

100

A Portable Eddy Covariance System for the Measurement of Ecosystem–Atmosphere Exchange of CO2, Water Vapor, and Energy  

Science Conference Proceedings (OSTI)

To facilitate the study of flux heterogeneity within a region, the authors have designed and field-tested a portable eddy covariance system to measure exchange of CO2, water vapor, and energy between the land surface and the atmosphere. The ...

D. P. Billesbach; M. L. Fischer; M. S. Torn; J. A. Berry

2004-04-01T23:59:59.000Z

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101

Integrity bases for covariants of tetrahedral XY4 molecules. Application to the electric dipole moment surface  

E-Print Network (OSTI)

Techniques of invariant theory such as Molien generating functions and integrity bases offer mathematical tools for the efficient construction of symmetry--adapted polynomials in the symmetrized coordinates of a molecular system. The present article is the prolongation of our previous work [P. Cassam-Chena\\"i and F. Patras, J. Math. Chem., 44(4), 938--966 (2008).] to the case of polynomials that transform as a non--totally symmetric irreducible representation of the symmetry group $G$ of the molecule. Such a covariant representation occurs with electric or magnetic properties, for example with the electric dipole moment surface. The symmetrized coordinates span an initial reducible representation from which polynomials transforming as an irreducible representation are built. The number of linearly independent polynomials of degree $k$ within this final representation is given by the coefficient of degree $k$ in the Taylor expansion of the associated Molien function. This generating function is built from combination of elementary generating functions where both the initial and final representations are irreducible. In parallel, Clebsch--Gordan coefficients of the symmetry group $G$ recursively couples the corresponding elementary integrity bases in order to build the integrity bases for the initial representation associated to symmetrized coordinates. The method is illustrated in detail on XY4 type of molecules for which the explicit integrity bases for the five final irreducible representations are given.

Patrick Cassam-Chenaï; Guillaume Dhont; Frédéric Patras

2013-11-04T23:59:59.000Z

102

Topological charges in SL(2,R) covariant massive 11-dimensional and type IIB supergravity  

Science Conference Proceedings (OSTI)

In this paper we construct closed expressions that correspond to the topological charges of the various 1/2-BPS states of the maximal 10- and 11-dimensional supergravity theories. These expressions are related to the structure of the supersymmetry algebras in curved spacetimes. We mainly focus on IIB supergravity and 11-dimensional supergravity in a double M9-brane background, with an emphasis on the SL(2,R) multiplet structure of the charges and how these map between theories. This includes the charges corresponding to the multiplets of 7- and 9-branes in IIB. We find that examining the possible multiplet structures of the charges provides another tool for exploring the spectrum of BPS states that appear in these theories. As a prerequisite to constructing the charges we determine the field equations and multiplet structure of the 11-dimensional gauge potentials, extending previous results on the subject. The massive gauge transformations of the fields are also discussed. We also demonstrate how these massive gauge transformations are compatible with the construction of an SL(2,R) covariant kinetic term in the 11-dimensional Kaluza-Klein monopole worldvolume action.

Callister, Andrew K.; Smith, Douglas J. [Department of Mathematical Sciences, University of Durham Science Laboratories, South Road, Durham DH1 3LE (United Kingdom)

2009-12-15T23:59:59.000Z

103

Lorentz-covariant Hamiltonian analysis of BF gravity with the Immirzi parameter  

E-Print Network (OSTI)

We perform the Lorentz-covariant Hamiltonian analysis of two Lagrangian action principles that describe general relativity as a constrained BF theory and that include the Immirzi parameter. The relation between these two Lagrangian actions has been already studied through a map among the fields involved. The main difference between these is the way the Immirzi parameter is included, since in one of them the Immirzi parameter is included explicitly in the BF terms, whereas in the other (the CMPR action) it is in the constraint on the B fields. In this work we continue the analysis of their relationship but at the Hamiltonian level. Particularly, we are interested in seeing how the above difference appears in the constraint structure of both action principles. We find that they both possess the same number of first-class and second-class constraints and satisfy a very similar (off-shell) Poisson-bracket algebra on account of the type of canonical variables employed. The two algebras can be transformed into each other by making a suitable change of variables

Mariano Celada; Merced Montesinos

2012-09-03T23:59:59.000Z

104

A fully covariant mean-field dynamo closure for numerical 3+1 resistive GRMHD  

E-Print Network (OSTI)

The powerful high-energy phenomena typically encountered in astrophysics invariably involve physical engines, like neutron stars and black hole accretion disks, characterized by a combination of highly magnetized plasmas, strong gravitational fields, and relativistic motions. In recent years numerical schemes for General Relativistic MHD (GRMHD) have been developed to model the multidimensional dynamics of such systems, including the possibility of an evolving spacetime. Such schemes have been also extended beyond the ideal limit including the effects of resistivity, in an attempt to model dissipative physical processes acting on small scales (sub-grid effects) over the global dynamics. Along the same lines, magnetic fields could be amplified by the presence of turbulent dynamo processes, as often invoked to explain the high values of magnetization required in accretion disks and neutron stars. Here we present, for the first time, a further extension to include the possibility of a mean-field dynamo action within the framework of numerical 3+1 (resistive) GRMHD. A fully covariant dynamo closure is proposed, in analogy with the classical theory, assuming a simple alpha-effect in the comoving frame. Its implementation into a finite-difference scheme for GRMHD in dynamical spacetimes [the X-ECHO code: (Bucciantini and Del Zanna 2011)] is described, and a set of numerical test is presented and compared with analytical solutions wherever possible.

N. Bucciantini; L. Del Zanna

2012-05-14T23:59:59.000Z

105

Covariance of dark energy parameters and sound speed constraints from large HI surveys  

E-Print Network (OSTI)

An interesting probe of the nature of dark energy is the measure of its sound speed, $c_s$. We review the significance for constraining sound speed models of dark energy using large neutral hydrogen (HI) surveys with the Square Kilometre Array (SKA). Our analysis considers the effect on the sound speed measurement that arises from the covariance of $c_s$ with the dark energy density, $\\Omega_\\LLambda$, and a time-varying equation of state, $w(a)=w_0+(1-a)w_a$. We find that the approximate degeneracy between dark energy parameters that arises in power spectrum observations is lifted through redshift tomography of the HI-galaxy angular power spectrum, resulting in sound speed constraints that are not severely degraded. The cross-correlation of the galaxy and the integrated Sachs-Wolfe (ISW) effect spectra contributes approximately 10 percent of the information that is needed to distinguish variations in the dark energy parameters, and most of the discriminating signal comes from the galaxy auto-correlation spectrum. We also find that the sound speed constraints are weakly sensitive to the HI bias model. These constraints do not improve substantially for a significantly deeper HI survey since most of the clustering sensitivity to sound speed variations arises from $z \\lsim 1.5$. A detection of models with sound speeds close to zero, $c_s \\lsim 0.01,$ is possible for dark energy models with $w\\gsim -0.9$.

A. Torres-Rodriguez; C. M. Cress; K. Moodley

2008-04-15T23:59:59.000Z

106

A highly portable, rapidly deployable system for eddy covariance measurements of CO2 fluxes  

DOE Green Energy (OSTI)

To facilitate the study of flux heterogeneity within a region, the authors have designed, built, and field-tested a highly portable, rapidly deployable, eddy covariance CO{sub 2} flux measurement system. The system is built from off-the-shelf parts and was assembled at a minimal cost. The unique combination of features of this system allow for a very rapid deployment with a minimal number of field personnel. The system is capable of making high precision, unattended measurements of turbulent CO{sub 2} fluxes, latent heat (LE) fluxes, sensible heat fluxes (H), and momentum transfer fluxes. In addition, many of the meteorological and ecosystem variables necessary for quality control of the fluxes and for running ecosystem models are measured. A side-by-side field comparison of the system at a pair of established AmeriFlux sites has verified that, for single measurements, the system is capable of CO{sub 2} flux accuracy of about {+-} 1.2 {micro}mole/m{sup 2}/sec, LE flux accuracy of about {+-} 15 Watts/m{sup 2}, H flux accuracy of about {+-} 7 Watts/m{sup 2}, and momentum transfer flux accuracy of about {+-} 11 gm-m/sec/sec. System deployment time is between 2 and 4 hours by a single person. The system was measured to draw between 30 and 35 Watts of power and may be run from available line power, storage batteries, or solar panels.

Billesbach, David P.; Fischer, Marc L.; Torn, Margaret S.; Berry, Joe A.

2001-09-19T23:59:59.000Z

107

Interpreting Dirac variables in terms of the Hilbert space of gauge-invariant and Poincare-covariant states  

E-Print Network (OSTI)

The goal of this note is to give a description of Dirac variables in Abelian as well as non-Abelian gauge models in terms of gauge-invariant and Poincare-covariant states sweeping a Hilbert space ${\\cal H}_{\\rm vac}$. The next our conjecture concerns the spontaneous breakdown of the Abelian U(1) symmetry in the 'discrete' $U(1)\\to {\\bf Z}$ wise. We suppose that gauge charges are preserved in this case.

L. D Lantsman

2011-10-14T23:59:59.000Z

108

Covariance statistics of turbulence velocity components for wind-energy-conversion system design-homogeneous, isotropic case  

DOE Green Energy (OSTI)

When designing a wind energy converison system (WECS), it may be necessary to take into account the distribution of wind across the disc of rotation. The specific engineering applications include structural strength, fatigue, and control. This wind distribution consists of two parts, namely that associated with the mean wind profile and that associated with the turbulence velocity fluctuation field. The work reported herein is aimed at the latter, namely the distribution of turbulence velocity fluctuations across the WECS disk of rotation. A theory is developed for the two-time covariance matrix for turbulence velocity vector components for wind energy conversion system (WECS) design. The theory is developed for homogeneous and iotropic turbulance with the assumption that Taylor's hypothesis is valid. The Eulerian turbulence velocity vector field is expanded about the hub of the WECS. Formulae are developed for the turbulence velocity vector component covariance matrix following the WECS blade elements. It is shown that upon specification of the turbulence energy spectrum function and the WECS rotation rate, the two-point, two-time covariance matrix of the turbulent flow relative to the WECS bladed elements is determined. This covariance matrix is represented as the sum of nonstationary and stationary contributions. Generalized power spectral methods are used to obtain two-point, double frequency power spectral density functions for the turbulent flow following the blade elements. The Dryden turbulence model is used to demonstrate the theory. A discussion of linear system response analysis is provided to show how the double frequency turbulence spectra might be used to calculate response spectra of a WECS to turbulent flow. Finally the spectrum of the component of turbulence normal to the WECS disc of rotation, following the blade elements, is compared with experimental results.

Fichtl, G.H.

1983-09-01T23:59:59.000Z

109

Measurements of Aerodynamic Roughness, Bowen Ratio, and Atmospheric Surface Layer Height by Eddy Covariance and Tethersonde Systems Simultaneously over a Heterogeneous Rice Paddy  

Science Conference Proceedings (OSTI)

The aerodynamic roughness, Bowen ratio, and friction velocity were measured over a rice paddy using tethersonde and eddy covariance (EC) systems. In addition, the height ranges of the atmospheric inertial sublayer (ISL) were derived using the ...

Jeng-Lin Tsai; Ben-Jei Tsuang; Po-Sheng Lu; Ken-Hui Chang; Ming-Hwi Yao; Yuan Shen

2010-04-01T23:59:59.000Z

110

Determination of Planetary Boundary Layer Height on Short Spatial and Temporal Scales: A Demonstration of the Covariance Wavelet Transform in Ground-Based Wind Profiler and Lidar Measurements  

Science Conference Proceedings (OSTI)

This article explores the application of the covariance wavelet transform (CWT) to lidar and, for the first time to the authors' knowledge, wind profiler data to examine the possibility of accurate and continuous planetary boundary layer (PBL) ...

Jaime C. Compton; Ruben Delgado; Timothy A. Berkoff; Raymond M. Hoff

2013-07-01T23:59:59.000Z

111

The Impact of Covariance Localization for Radar Data on EnKF Analyses of a Developing MCS: Observing System Simulation Experiments  

Science Conference Proceedings (OSTI)

Several observing system simulation experiments (OSSEs) were performed to assess the impact of covariance localization of radar data on ensemble Kalman filter (EnKF) analyses of a developing convective system. Simulated Weather Surveillance Radar-...

Ryan A. Sobash; David J. Stensrud

2013-11-01T23:59:59.000Z

112

Sensible Heat Flux by Surface Layer Scintillometry and Eddy Covariance over a Mixed Grassland Community as Affected by Bowen Ratio and MOST Formulations for Unstable Conditions  

Science Conference Proceedings (OSTI)

Measurements of sensible heat flux for an extended period for unstable conditions using surface layer scintillometry (SLS) and eddy covariance (EC) and supplemented by Bowen ratio measurements for a mixed grassland community on the eastern ...

G. O. Odhiambo; M. J. Savage

2009-04-01T23:59:59.000Z

113

The impact of covariance localization for radar data on enKF analyses of a developing MCS: Observing system simulation experiments  

Science Conference Proceedings (OSTI)

Several observing system simulation experiments (OSSEs) were performed to assess the impact of covariance localization of radar data on ensemble Kalman filter (EnKF) analyses of a developing convective system. Simulated WSR-88D radar observations ...

Ryan A. Sobash; David J. Stensrud

114

Continuous reservoir model updating using an ensemble Kalman filter with a streamline-based covariance localization  

E-Print Network (OSTI)

This work presents a new approach that combines the comprehensive capabilities of the ensemble Kalman filter (EnKF) and the flow path information from streamlines to eliminate and/or reduce some of the problems and limitations of the use of the EnKF for history matching reservoir models. The recent use of the EnKF for data assimilation and assessment of uncertainties in future forecasts in reservoir engineering seems to be promising. EnKF provides ways of incorporating any type of production data or time lapse seismic information in an efficient way. However, the use of the EnKF in history matching comes with its shares of challenges and concerns. The overshooting of parameters leading to loss of geologic realism, possible increase in the material balance errors of the updated phase(s), and limitations associated with non-Gaussian permeability distribution are some of the most critical problems of the EnKF. The use of larger ensemble size may mitigate some of these problems but are prohibitively expensive in practice. We present a streamline-based conditioning technique that can be implemented with the EnKF to eliminate or reduce the magnitude of these problems, allowing for the use of a reduced ensemble size, thereby leading to significant savings in time during field scale implementation. Our approach involves no extra computational cost and is easy to implement. Additionally, the final history matched model tends to preserve most of the geological features of the initial geologic model. A quick look at the procedure is provided that enables the implementation of this approach into the current EnKF implementations. Our procedure uses the streamline path information to condition the covariance matrix in the Kalman Update. We demonstrate the power and utility of our approach with synthetic examples and a field case. Our result shows that using the conditioned technique presented in this thesis, the overshooting/undershooting problems disappears and the limitation to work with non- Gaussian distribution is reduced. Finally, an analysis of the scalability in a parallel implementation of our computer code is given.

Arroyo Negrete, Elkin Rafael

2006-12-01T23:59:59.000Z

115

Gel'fand-Zetlin Basis and Clebsch-Gordan Coefficients for Covariant Representations of the Lie superalgebra gl(m|n)  

E-Print Network (OSTI)

A Gel'fand-Zetlin basis is introduced for the irreducible covariant tensor representations of the Lie superalgebra gl(m|n). Explicit expressions for the generators of the Lie superalgebra acting on this basis are determined. Furthermore, Clebsch-Gordan coefficients corresponding to the tensor product of any covariant tensor representation of gl(m|n) with the natural representation V ([1,0,...,0]) of gl(m|n) with highest weight (1,0,. . . ,0) are computed. Both results are steps for the explicit construction of the parastatistics Fock space.

N. I. Stoilova; J. Van der Jeugt

2010-04-14T23:59:59.000Z

116

Low energy analysis of $\\pi N$ scattering and the pion-nucleon sigma term with covariant baryon chiral perturbation theory  

E-Print Network (OSTI)

The pion-nucleon sigma term ($\\sigma_{\\pi N}$) is an observable of fundamental importance because embodies information about the internal scalar structure of the nucleon. Nowadays this quantity has triggered renewed interest because it is a key input for a reliable estimation of the dark matter-nucleon spin independent elastic scattering cross section. In this proceeding we present how this quantity can be reliably extracted by employing only experimental information with the use covariant baryon chiral perturbation theory. We also contrast our extraction with updated phenomenology related to $\\sigma_{\\pi N}$ and show how this phenomenology favours a relatively large value of $\\sigma_{\\pi N}$. Finally, we extract a value of $\\sigma_{\\pi N}=59(7)$ MeV from modern partial wave analyses data.

Alarcón, J M; Oller, J A

2013-01-01T23:59:59.000Z

117

Low energy analysis of $?N$ scattering and the pion-nucleon sigma term with covariant baryon chiral perturbation theory  

E-Print Network (OSTI)

The pion-nucleon sigma term ($\\sigma_{\\pi N}$) is an observable of fundamental importance because embodies information about the internal scalar structure of the nucleon. Nowadays this quantity has triggered renewed interest because it is a key input for a reliable estimation of the dark matter-nucleon spin independent elastic scattering cross section. In this proceeding we present how this quantity can be reliably extracted by employing only experimental information with the use covariant baryon chiral perturbation theory. We also contrast our extraction with updated phenomenology related to $\\sigma_{\\pi N}$ and show how this phenomenology favours a relatively large value of $\\sigma_{\\pi N}$. Finally, we extract a value of $\\sigma_{\\pi N}=59(7)$ MeV from modern partial wave analyses data.

J. M. Alarcón; J. Martin Camalich; J. A. Oller

2013-01-14T23:59:59.000Z

118

Constraint damping of the conformal and covariant formulation of the Z4 system in simulations of binary neutron stars  

E-Print Network (OSTI)

Following previous work in vacuum spacetimes, we investigate the constraint-damping properties in the presence of matter of the recently developed traceless, conformal and covariant Z4 (CCZ4) formulation of the Einstein equations. First, we evolve an isolated neutron star with an ideal gas equation of state and subject to a constraint-violating perturbation. We compare the evolution of the constraints using the CCZ4 and Baumgarte-Shibata-Shapiro-Nakamura-Oohara-Kojima (BSSNOK) systems. Second, we study the collapse of an unstable spherical star to a black hole. Finally, we evolve binary neutron star systems over several orbits until the merger, the formation of a black hole, and up to the ringdown. We show that the CCZ4 formulation is stable in the presence of matter and that the constraint violations are one or more orders of magnitude smaller than for the BSSNOK formulation. Furthermore, by comparing the CCZ4 and the BSSNOK formulations also for neutron star binaries with large initial constraint violations, we investigate their influence on the errors on physical quantities. We also give a new, simple and robust prescription for the damping parameter that removes the instabilities found when using the fully covariant version of CCZ4 in the evolution of black holes. Overall, we find that at essentially the same computational costs the CCZ4 formulation provides solutions that are stable and with a considerably smaller violation of the Hamiltonian constraint than the BSSNOK formulation. We also find that the performance of the CCZ4 formulation is very similar to another conformal and traceless, but noncovariant formulation of the Z4 system, i.e. the Z4c formulation.

Daniela Alic; Wolfgang Kastaun; Luciano Rezzolla

2013-07-28T23:59:59.000Z

119

Satellite-Based Modeling of the Carbon Fluxes in Mature Black Spruce Forests in Alaska: A Synthesis of the Eddy Covariance Data and Satellite Remote Sensing Data  

Science Conference Proceedings (OSTI)

Scaling up of observed point data to estimate regional carbon fluxes is an important issue in the context of the global terrestrial carbon cycle. In this study, the authors proposed a new model to scale up the eddy covariance data to estimate ...

Masahito Ueyama; Yoshinobu Harazono; Kazuhito Ichii

2010-10-01T23:59:59.000Z

120

Environmental Controls on the Surface Energy Budget over a Large Southern Inland Water in the United States: An Analysis of One-Year Eddy Covariance Flux Data  

Science Conference Proceedings (OSTI)

The authors analyzed the surface energy fluxes that were measured by an eddy covariance system over the Ross Barnett Reservoir in Mississippi for a 1-yr period in 2008. On a monthly basis over the course of the year, positive vertical temperature ...

Heping Liu; Qianyu Zhang; Gordon Dowler

2012-12-01T23:59:59.000Z

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121

Relative Humidity Effect on the High-Frequency Attenuation of Water Vapor Flux Measured by a Closed-Path Eddy Covariance System  

Science Conference Proceedings (OSTI)

In this study the high-frequency loss of carbon dioxide (CO2) and water vapor (H2O) fluxes, measured by a closed-path eddy covariance system, were studied, and the related correction factors through the cospectral transfer function method were ...

Ivan Mammarella; Samuli Launiainen; Tiia Gronholm; Petri Keronen; Jukka Pumpanen; Üllar Rannik; Timo Vesala

2009-09-01T23:59:59.000Z

122

Theos J. Thompson, 1964 | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

& Selection Guidelines Award Laureates 2000's 1990's 1980's 1970's 1960's Ceremony The Life of Ernest Orlando Lawrence Contact Information The Ernest Orlando Lawrence Award U.S....

123

ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data  

Science Conference Proceedings (OSTI)

The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 423 nuclides; (2) Covariance uncertainty data for 190 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He; Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions for isotopes of Cl; K; Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides (235,238)U and (239)Pu at this point, except for delayed neutron data and covariances, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es; Fm; and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on (239)Pu; and (9) A new decay data sublibrary. Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0 for a wide range of MCNP simulations of criticality benchmarks, with improved performance coming from new structural material evaluations, especially for Ti, Mn, Cr, Zr and W. For Be we see some improvements although the fast assembly data appear to be mutually inconsistent. Actinide cross section updates are also assessed through comparisons of fission and capture reaction rate measurements in critical assemblies and fast reactors, and improvements are evident. Maxwellian-averaged capture cross sections at 30 keV are also provided for astrophysics applications. We describe the cross section evaluations that have been updated for ENDF/B-VII.1 and the measured data and calculations that motivated the changes, and therefore this paper augments the ENDF/B-VII.0 publication [H.

Chadwick, M. B. [Los Alamos National Laboratory (LANL); Herman, Micheal W [Brookhaven National Laboratory (BNL); Oblozinsky, Pavel [Brookhaven National Laboratory (BNL); Dunn, Michael E [ORNL; Danon, Y. [Rensselaer Polytechnic Institute (RPI); Kahler, A. [Los Alamos National Laboratory (LANL); Smith, Donald L. [Argonne National Laboratory (ANL); Pritychenko, B [Brookhaven National Laboratory (BNL); Arbanas, Goran [ORNL; Arcilla, r [Brookhaven National Laboratory (BNL); Brewer, R [Los Alamos National Laboratory (LANL); Brown, D A [Brookhaven National Laboratory (BNL); Capote, R. [International Atomic Energy Agency (IAEA); Carlson, A. D. [National Institute of Standards and Technology (NIST); Cho, Y S [Korea Atomic Energy Research Institute; Derrien, Herve [ORNL; Guber, Klaus H [ORNL; Hale, G. M. [Los Alamos National Laboratory (LANL); Hoblit, S [Brookhaven National Laboratory (BNL); Holloway, Shannon T. [Los Alamos National Laboratory (LANL); Johnson, T D [Brookhaven National Laboratory (BNL); Kawano, T. [Los Alamos National Laboratory (LANL); Kiedrowski, B C [Los Alamos National Laboratory (LANL); Kim, H [Korea Atomic Energy Research Institute; Kunieda, S [Los Alamos National Laboratory (LANL); Larson, Nancy M [ORNL; Leal, Luiz C [ORNL; Lestone, J P [Los Alamos National Laboratory (LANL); Little, R C [Los Alamos National Laboratory (LANL); Mccutchan, E A [Brookhaven National Laboratory (BNL); Macfarlane, R E [Los Alamos National Laboratory (LANL); MacInnes, M [Los Alamos National Laboratory (LANL); Matton, C M [Lawrence Livermore National Laboratory (LLNL); Mcknight, R D [Argonne National Laboratory (ANL); Mughabghab, S F [Brookhaven National Laboratory (BNL); Nobre, G P [Brookhaven National Laboratory (BNL); Palmiotti, G [Idaho National Laboratory (INL); Palumbo, A [Brookhaven National Laboratory (BNL); Pigni, Marco T [ORNL; Pronyaev, V. G. [Institute of Physics and Power Engineering (IPPE), Obninsk, Russia; Sayer, Royce O [ORNL; Sonzogni, A A [Brookhaven National Laboratory (BNL); Summers, N C [Lawrence Livermore National Laboratory (LLNL); Talou, P [Los Alamos National Laboratory (LANL); Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Trkov, A. [Jozef Stefan Institute, Slovenia; Vogt, R L [Lawrence Livermore National Laboratory (LLNL); Van der Marck, S S [Nucl Res & Consultancy Grp, Petten, Netherlands; Wallner, A [University of Vienna, Austria; White, M C [Los Alamos National Laboratory (LANL); Wiarda, Dorothea [ORNL; Young, P C [Los Alamos National Laboratory (LANL)

2011-01-01T23:59:59.000Z

124

The REFLEX project: Comparing different algorithms and implementations for the inversion of a terrestrial ecosystem model against eddy covariance data  

DOE Green Energy (OSTI)

We describe a model-data fusion (MDF) inter-comparison project (REFLEX), which compared various algorithms for estimating carbon (C) model parameters consistent with both measured carbon fluxes and states and a simple C model. Participants were provided with the model and with both synthetic net ecosystem exchange (NEE) ofCO2 and leaf area index (LAI) data, generated from the model with added noise, and observed NEE and LAI data from two eddy covariance sites. Participants endeavoured to estimate model parameters and states consistent with the model for all cases over the two years for which data were provided, and generate predictions for one additional year without observations. Nine participants contributed results using Metropolis algorithms, Kalman filters and a genetic algorithm. For the synthetic data case, parameter estimates compared well with the true values. The results of the analyses indicated that parameters linked directly to gross primary production (GPP) and ecosystem respiration, such as those related to foliage allocation and turnover, or temperature sensitivity of heterotrophic respiration,were best constrained and characterised. Poorly estimated parameters were those related to the allocation to and turnover of fine root/wood pools. Estimates of confidence intervals varied among algorithms, but several algorithms successfully located the true values of annual fluxes from synthetic experiments within relatively narrow 90% confidence intervals, achieving>80% success rate and mean NEE confidence intervals <110 gCm-2 year-1 for the synthetic case. Annual C flux estimates generated by participants generally agreed with gap-filling approaches using half-hourly data. The estimation of ecosystem respiration and GPP through MDF agreed well with outputs from partitioning studies using half-hourly data. Confidence limits on annual NEE increased by an average of 88% in the prediction year compared to the previous year, when data were available. Confidence intervals on annual NEE increased by 30% when observed data were used instead of synthetic data, reflecting and quantifying the addition of model error. Finally, our analyses indicated that incorporating additional constraints, using data on C pools (wood, soil and fine roots) would help to reduce uncertainties for model parameters poorly served by eddy covariance data.

Fox, Andrew [University of Sheffield; Williams, Mathew [University of Edinburgh; Richardson, Andrew D. [Harvard University; Cameron, David [Centre for Ecology and Hydrology, Bush Estate; Gove, Jeffrey H. [USDA Forest Service; Quaife, Tristan [University College, London; Ricciuto, Daniel M [ORNL; Reichstein, Markus [Max Planck Institute for Biogeochemistry; Tomelleri, Enrico [Max Planck Institute for Biogeochemistry; Trudinger, Cathy [CSIRO Marine and Atmospheric Research; Van Wijk, Mark T. [Wageningen University and Research Centre, The Netherlands

2009-10-01T23:59:59.000Z

125

ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data  

SciTech Connect

The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. The principal advances in the new library are: (1) An increase in the breadth of neutron reaction cross section coverage, extending from 393 nuclides to 418 nuclides; (2) Covariance uncertainty data for 185 of the most important nuclides, as documented in companion papers in this edition; (3) R-matrix analyses of neutron reactions on light nuclei, including isotopes of He, Li, and Be; (4) Resonance parameter analyses at lower energies and statistical high energy reactions at higher energies for isotopes of F, Cl, K, Ti, V, Mn, Cr, Ni, Zr and W; (5) Modifications to thermal neutron reactions on fission products (isotopes of Mo, Tc, Rh, Ag, Cs, Nd, Sm, Eu) and neutron absorber materials (Cd, Gd); (6) Improved minor actinide evaluations for isotopes of U, Np, Pu, and Am (we are not making changes to the major actinides 235,238U and 239Pu at this point, except for delayed neutron data, and instead we intend to update them after a further period of research in experiment and theory), and our adoption of JENDL-4.0 evaluations for isotopes of Cm, Bk, Cf, Es, Fm, and some other minor actinides; (7) Fission energy release evaluations; (8) Fission product yield advances for fission-spectrum neutrons and 14 MeV neutrons incident on 239Pu; and (9) A new Decay Data sublibrary. Integral validation testing of the ENDF/B-VII.1 library is provided for a variety of quantities: For nuclear criticality, the VII.1 library maintains the generally-good performance seen for VII.0 for a wide range of MCNP simulations of criticality benchmarks, with improved performance coming from new structural material evaluations, especially for Ti, Mn, Cr, Zr and W. For Be we see some improvements although the fast assembly data appear to be mutually inconsistent. Actinide cross section updates are also assessed through comparisons of fission and capture reaction rate measurements in critical assemblies and fast reactors. We describe the cross section evaluations that have been updated for ENDF/B-VII.1 and the measured data and calculations that motivated the changes, and therefore this paper augments the ENDF/B-VII.0 publication [1].

G. Palmiotti

2011-12-01T23:59:59.000Z

126

Spherically symmetric solutions, Newton's Law, and the infrared limit {lambda}{yields}1 in covariant Horava-Lifshitz gravity  

SciTech Connect

In this note we examine whether spherically symmetric solutions in covariant Horava-Lifshitz gravity can reproduce Newton's Law in the IR limit {lambda}{yields}1. We adopt the position that the auxiliary field A is independent of the space-time metric [J. Alexandre and P. Pasipoularides, Phys. Rev. D 83, 084030 (2011).][J. Greenwald, V. H. Satheeshkumar, and A. Wang, J. Cosmol. Astropart. Phys. 12 (2010) 007.], and we assume, as in [A. M. da Silva, Classical Quantum Gravity 28, 055011 (2011).], that {lambda} is a running coupling constant. We show that under these assumptions, spherically symmetric solutions fail to restore the standard Newtonian physics in the IR limit {lambda}{yields}1, unless {lambda} does not run, and has the fixed value {lambda}=1. Finally, we comment on the Horava and Melby-Thompson approach [P. Horava and C. M. Melby-Thompson, Phys. Rev. D 82, 064027 (2010).] in which A is assumed as a part of the space-time metric in the IR.

Alexandre, Jean [King's College London, Department of Physics, London WC2R 2LS (United Kingdom); Pasipoularides, Pavlos [Department of Physics, National Technical University of Athens, Zografou Campus GR 157 73, Athens (Greece)

2011-10-15T23:59:59.000Z

127

Covariant analysis of Newtonian multi-fluid models for neutron stars: II Stress - energy tensors and virial theorems  

E-Print Network (OSTI)

The 4-dimensionally covariant approach to multiconstituent Newtonian fluid dynamics presented in the preceding article of this series is developed by construction of the relevant 4-dimensional stress energy tensor whose conservation in the non-dissipative variational case is shown to be interpretable as a Noether identity of the Milne spacetime structure. The formalism is illustrated by the application to homogeneously expanding cosmological models, for which appropriately generalised local Bernouilli constants are constructed. Another application is to the Iordanski type generalisation of the Joukowski formula for the Magnus force on a vortex. Finally, at a global level, a new (formally simpler but more generally applicable) version of the ``virial theorem'' is obtained for multiconsituent -- neutron or other -- fluid star models as a special case within an extensive category of formulae whereby the time evolution of variously weighted mass moment integrals is determined by corresponding space integrals of stress tensor components, with the implication that all such stress integrals must vanish for any stationary equilibrium configuration.

Brandon Carter; Nicolas Chamel

2003-12-16T23:59:59.000Z

128

Assessing net ecosystem carbon exchange of U S terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations  

Science Conference Proceedings (OSTI)

More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr 1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr 1 over the period 2001 2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by 20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.

Zhuang, Qianlai [Purdue University; Law, Beverly E. [Oregon State University; Baldocchi, Dennis [University of California, Berkeley; Ma, Siyan [University of California, Berkeley; Chen, Jiquan [University of Toledo, Toledo, OH; Richardson, Andrew [Harvard University; Melillo, Jerry [Marine Biological Laboratory; Davis, Ken J. [Pennsylvania State University; Hollinger, D. [USDA Forest Service; Wharton, Sonia [University of California, Davis; Falk, Matthias [University of California, Davis; Paw, U. Kyaw Tha [University of California, Davis; Oren, Ram [Duke University; Katulk, Gabriel G. [Duke University; Noormets, Asko [North Carolina State University; Fischer, Marc [Lawrence Berkeley National Laboratory (LBNL); Verma, Shashi [University of Nebraska; Suyker, A. E. [University of Nebraska, Lincoln; Cook, David R. [Argonne National Laboratory (ANL); Sun, G. [USDA Forest Service; McNulty, Steven G. [USDA Forest Service; Wofsy, Steve [Harvard University; Bolstad, Paul V [University of Minnesota; Burns, Sean [University of Colorado, Boulder; Monson, Russell K. [University of Colorado, Boulder; Curtis, Peter [Ohio State University, The, Columbus; Drake, Bert G. [Smithsonian Environmental Research Center, Edgewater, MD; Foster, David R. [Harvard University; Gu, Lianhong [ORNL; Hadley, Julian L. [Harvard University; Litvak, Marcy [University of New Mexico, Albuquerque; Martin, Timothy A. [University of Florida, Gainesville; Matamala, Roser [Argonne National Laboratory (ANL); Meyers, Tilden [NOAA, Oak Ridge, TN; Oechel, Walter C. [San Diego State University; Schmid, H. P. [Indiana University; Scott, Russell L. [USDA ARS; Torn, Margaret S. [Lawrence Berkeley National Laboratory (LBNL)

2011-01-01T23:59:59.000Z

129

Skukuza Eddy Covariance Photos  

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

Courtesy of Robert Cook Photo Courtesy of Robert Cook Photos of the Landscape from the tower View to the North View to the East View to the South Site photos from the dry season...

130

VNA covariance _14_  

Science Conference Proceedings (OSTI)

... with the use of 1.0 mm coaxial short-open-load-through (SOLT ... the impact of mismatch correction uncertainty on the impulse response uncertainties. ...

2012-09-08T23:59:59.000Z

131

1404 JOURNAL OF CLIMATE VOLUME 16 Covariations of Sea Surface Temperature and Wind over the Kuroshio and Its Extension: Evidence for Ocean-to-Atmosphere Feedback*  

E-Print Network (OSTI)

Satellite microwave measurements are analyzed, revealing robust covariability in sea surface temperature (SST) and wind speed over the Kuroshio Extension (KE) east of Japan. Ocean hydrodynamic instabilities cause the KE to meander and result in large SST variations. Increased (reduced) wind speeds are found to be associated with warm (cold) SST anomalies. This positive SST–wind correlation in KE is confirmed by in situ buoy measurements and is consistent with a vertical shear adjustment mechanism. Namely, an increase in SST reduces the static stability of the near-surface atmosphere, intensifying the vertical turbulence mixing and bringing fastmoving air from aloft to the sea surface. South of Japan, the Kuroshio is known to vary between nearshore and offshore paths. These paths are very persistent and can last for months to years. As the Kuroshio shifts its path, coherent wind changes are detected from satellite data. In particular, winds are high south of Tokyo when the Kuroshio takes the nearshore path while they are greatly reduced when this warm current leaves the coast in the offshore path. The positive SST–wind correlation over the strong Kuroshio Current and its extension is opposite to the negative one often observed in regions of weak currents such as south of the Aleutian low. The latter correlation is considered to be indicative of atmosphere-to-ocean forcing. 1.

Masami Nonaka; Shang-ping Xie

2002-01-01T23:59:59.000Z

132

Optimal basis set for ab-initio calculations of energy levels in tunneling structures, using the covariance matrix of the wave functions  

E-Print Network (OSTI)

The paper proposes a method to obtain the optimal basis set for solving the self consistent field (SCF) equations for large atomic systems in order to calculate the energy barriers in tunneling structures, with higher accuracy and speed. Taking into account the stochastic-like nature of the samples of all the involved wave functions for many body problems, a statistical optimization is made by considering the covariance matrix of these samples. An eigenvalues system is obtained and solved for the optimal basis set and by inspecting the rapidly decreasing eigenvalues one may seriously reduce the necessary number of vectors that insures an imposed precision. This leads to a potentially significant improvement in the speed of the SCF calculations and accuracy, as the statistical properties of a large number of wave functions in an large spatial domain may be considered. The eigenvalue problem has to be solved only few times, so that the amount of time added may be much smaller that the overall iterating SCF calculations. A simple implementation of the method is presented for a situation where the analytical solution is known, and the results are encouraging.

Sever Spanulescu

2009-12-15T23:59:59.000Z

133

Covariant isolation from an Abelian gauge field of its nondynamical potential, which, when fed back, can transform into a "confining Yukawa"  

E-Print Network (OSTI)

For Abelian gauge theory a properly relativistic gauge is developed by supplementing the Lorentz condition with causal determination of the time component of the four-vector potential by retarded Coulomb transformation of the charge density. This causal Lorentz gauge agrees with the Coulomb gauge for static charge densities, but allows the four-vector potential to have a longitudinal component that is determined by the time derivative of the four-vector potential's time component. Just as in Coulomb gauge, the two transverse components of the four-vector potential are its sole dynamical part. The four-vector potential in this gauge covariantly separates into a dynamical transverse four-vector potential and a nondynamical timelike/longitudinal four-vector potential, where each of these two satisfies the Lorentz condition. In fact, analogous partition of the conserved four-current shows each to satisfy a Lorentz-condition Maxwell equation system with its own conserved four-current. Because of this complete separation, either of these four-vector potentials can be tinkered with without affecting its counterpart. Since it satisfies the Lorentz condition, the nondynamical four-vector potential times a constant with dimension of inverse length squared is itself a conserved four-current, and so can be fed back into its own source current, which transforms its time component into an extended Yukawa, with both exponentially decaying and exponentially growing components. The latter might be the mechanism of quark-gluon confinement: in non-Abelian color gauge theory the Yukawa mixture ratio ought to be tied to color, with palpable consequences for "colorful" hot quark-gluon plasmas.

Steven Kenneth Kauffmann

2010-05-06T23:59:59.000Z

134

A Numerical Study of the Influence of a Clearcut on Eddy-Covariance Fluxes of CO2 Measured Above a Forest  

Science Conference Proceedings (OSTI)

We compare the contributions of unit source fluxes over a clear-cutting area in a forest and over the contiguous forested area to the eddy-covariance (EC) flux of CO2 measured at a tower standing in the center of the clearcut under daytime convective conditions. The large-eddy simulation (LES) technique is used to simulate the dispersion and transport of two conservative and passive tracers that are released from the clearcut and from the forested area, respectively. The time series of the LES-generated vertical velocity and the mixing ratios of both tracers on all the levels at the tower location are recorded every model time step during the last hour of each LES run; this somewhat mimics real EC flux measurements at the tower. The contribution of the unit surface flux over the clearcut relative to that over the forested area decreases exponentially with increasing measurement height, decreasing convective boundary layer depth, increasing atmospheric stability, and decreasing size of the clearcut. LES-derived results are fitted to an empirical relation and applied to flux measurements at the 447-m tall tower in Wisconsin, USA. The contribution of the unit flux over the clearcut on the EC flux measured at the 30-m level of the tower is larger than 50% of that over the forested area under most unstable conditions, while smaller than 2.5% at the 396-m level. Existing analytical footprint models are inappropriate to address the clearcut influence due to clearcut-induced heterogeneity of the turbulent flow in the tower area.

Wang, Weiguo; Davis, Kenneth J.

2008-09-03T23:59:59.000Z

135

7, 1315113173, 2007 Eddy covariance  

E-Print Network (OSTI)

) technique has been an important development toward un-20 derstanding plant growth and energy balance Department of Plant Sciences, U.C. Davis, Davis CA 95616, USA Received: 30 July 2007 ­ Accepted: 31 August conditions. The power spectrum of the vertical wind clearly shows5 that the inertial subrange

Paris-Sud XI, Université de

136

Estimation of multi-group cross section covariances for {sup 235,238}U, {sup 239}Pu, {sup 241}Am, {sup 56}Fe, {sup 23}Na and {sup 27}Al  

Science Conference Proceedings (OSTI)

This paper presents the methodology used to estimate multi-group covariances for some major isotopes used in reactor physics. The starting point of this evaluation is the modelling of the neutron induced reactions based on nuclear reaction models with parameters. These latest are the vectors of uncertainties as they are absorbing uncertainties and correlation arising from the confrontation of nuclear reaction model to microscopic experiment. These uncertainties are then propagated towards multi-group cross sections. As major breakthroughs were then asked by nuclear reactor physicists to assess proper uncertainties to be used in applications, a solution is proposed by the use of integral experiment information at two different stages in the covariance estimation. In this paper, we will explain briefly the treatment of all type of uncertainties, including experimental ones (statistical and systematic) as well as those coming from validation of nuclear data on dedicated integral experiment (nuclear data oriented). We will illustrate the use of this methodology with various isotopes such as {sup 235,238}U, {sup 239}Pu, {sup 241}Am, {sup 56}Fe, {sup 23}Na and {sup 27}Al. (authors)

De Saint Jean, C.; Archier, P.; Noguere, G.; Litaize, O.; Vaglio-Gaudard, C.; Bernard, D.; Leray, O. [CEA, DEN, DER, Cadarache, F-13108 Saint-Paul-lez-Durance (France)

2012-07-01T23:59:59.000Z

137

Mô h?nh T?i ?u Hóa N?i Tr?i theo Xác Su?t ?u Th?  

E-Print Network (OSTI)

Artificial Intelligence (ICTAI'2003), pages 149-156, Los Alamitos, CA, November 2003. Sacramento,. California, IEEE Computer Society, (2003). [14] Ragsdell ...

138

On the Covariant Quantization of QED  

E-Print Network (OSTI)

The commutation relations for bosons are field independent, and can be reliably inferred from the definition of creation and annihilation operators. Here, the commutation relations are assumed known, and the quantum electrodynamics equations without sources are quantized with the unmodified Lagrangian. Non diagonal products of creation and annihilation operators of the form, cr(0)an(3)+ cr(3)an(0), where 0,3 denote respectively the time-like and longitudinal-polarizations, are present in both terms that contribute to the Hamiltonian. However, the contributions differ in sign, and therefore cancel. In units of the photon's energy the coefficients of the Hamiltonian's four polarization states are -1/2, 1, 1, 1/2, clearly revealing the unphysical character of the time like and longitudinal polarization states. If the physical states are restricted to those that do not contain unphysical polarization states, and if the Lorentz condition is satisfied, then the non diagonal terms of the field's momentum vanish, and both the Hamiltonian and Momentum are well behaved. A transformation of the basic vectors engenders in turn a transformation of the creation operators. The expression for the transformation that leaves invariant the commutation relations is derived.

Bernard R. Durney

2013-09-12T23:59:59.000Z

139

Galilean Covariance versus Gauge Invariance Germain Rousseaux  

E-Print Network (OSTI)

existence of a superior principle called Gauge Symmetry which would rule all the laws of Physics: Phys- ical-343, 1997. [17] E. Guyon, J.-P. Hulin, L. Petit and C. D. Mitescu, Phys- ical Hydrodynamics, Oxford

Paris-Sud XI, Université de

140

Covariance regularization in inverse space - Optimization Online  

E-Print Network (OSTI)

Apr 1, 2009 ... In the present paper, we propose an alternative method for the regularization of ...... in white). The enlarged area in panel corresponds to the dashed square in panel (a) and the ...... 33'? ads 3,6;. With Eq. (92), the ?rst term ...

Note: This page contains sample records for the topic "leventis theo covary" 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

Density-dependent covariant energy density functionals  

Science Conference Proceedings (OSTI)

Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

Lalazissis, G. A. [Physics Department, Aristotle University of Thessaloniki, GR-54124 (Greece)

2012-10-20T23:59:59.000Z

142

The Design and Analysis of Salmonid Tagging Studies in the Columbia Basin : Volume XVII : Effects of Ocean Covariates and Release Timing on First Ocean-Year Survival of Fall Chinook Salmon from Oregon and Washington Coastal Hatcheries.  

DOE Green Energy (OSTI)

Effects of oceanographic conditions, as well as effects of release-timing and release-size, on first ocean-year survival of subyearling fall chinook salmon were investigated by analyzing CWT release and recovery data from Oregon and Washington coastal hatcheries. Age-class strength was estimated using a multinomial probability likelihood which estimated first-year survival as a proportional hazards regression against ocean and release covariates. Weight-at-release and release-month were found to significantly effect first year survival (p < 0.05) and ocean effects were therefore estimated after adjusting for weight-at-release. Negative survival trend was modeled for sea surface temperature (SST) during 11 months of the year over the study period (1970-1992). Statistically significant negative survival trends (p < 0.05) were found for SST during April, June, November and December. Strong pairwise correlations (r > 0.6) between SST in April/June, April/November and April/December suggest the significant relationships were due to one underlying process. At higher latitudes (45{sup o} and 48{sup o}N), summer upwelling (June-August) showed positive survival trend with survival and fall (September-November) downwelling showed positive trend with survival, indicating early fall transition improved survival. At 45{sup o} and 48{sup o}, during spring, alternating survival trends with upwelling were observed between March and May, with negative trend occurring in March and May, and positive trend with survival occurring in April. In January, two distinct scenarios of improved survival were linked to upwelling conditions, indicated by (1) a significant linear model effect (p < 0.05) showing improved survival with increasing upwelling, and (2) significant bowl-shaped curvature (p < 0.05) of survival with upwelling. The interpretation of the effects is that there was (1) significantly improved survival when downwelling conditions shifted to upwelling conditions in January (i.e., early spring transition occurred, p < 0.05), (2) improved survival during strong downwelling conditions (Bakun units < -250). Survival decreased during weak downwelling conditions (Bakun units between -180 and -100). Strong to moderately strong correlations between January upwelling and April SST (r = 0.5), June SST (r = 0.6), and the North Pacific Index (NPI) of Aleutian Low strength (r > 0.7) suggest January is a period when important effects originate and play out over ensuing months. Significant inverse trend with survival (p < 0.05) was found for Bakun indices in December, indicating strong downwelling improved survival. Higher-than-average adult return rates were observed for cohorts from brood-years 1982-1983, strong El Nino years. Individual hatcheries were found to have unique age-class strength and age-at-return characteristics.

Burgess, Caitlin; Skalski, John R.

2001-05-01T23:59:59.000Z

143

Assemblies of Nanoparticles as 3D Scaffolds for New Materials: from Mechanically Strong Polymer Crosslinked Aerogels  

E-Print Network (OSTI)

Crosslinked Aerogels to Porous Metals and Ceramics Nicholas Leventis Department of Chemistry, Missouri S of nanoparticles known as aerogels come at a high cost: fragility. A recent breakthrough at MS&T is the development of X-aerogels where skeletal inorganic nanoparticles (e.g., silica and >30 other metal oxides

Yamilov, Alexey

144

„Felsenwand“ vs. „Blumental“: Fremdwahrnehmung und Selbststilisierung in J.G. Seumes Mein Sommer 1805  

E-Print Network (OSTI)

In: Schillers Werke. Bd. 2.I, hrsg. v. Norbert Oellers u.a.Anne und Theo Harden [Hrsg. ]: Reisen im Diskurs. ModelleAnne und Theo Harden [Hrsg. ]: Reisen im Diskurs. Modelle

Starzinger, Jakob

2005-01-01T23:59:59.000Z

145

TMS 2012: Continuing Education  

Science Conference Proceedings (OSTI)

Speaker: Theo Lehner, Boliden Mineral AB, Sweden. Topic: Conservation & Development: Industrial Learning in Non-Ferrous Smelting. [LEARN MORE] ...

146

Mean and covariance matrix adaptive estimation for a weakly ...  

E-Print Network (OSTI)

Summary: We introduce an adaptive algorithm to estimate the uncertain ... a trade -off between the mean cost E[?rN+1x] = ??N+1x and its standard deviation.

147

Newton-Like Methods for Sparse Inverse Covariance Estimation  

E-Print Network (OSTI)

Jun 7, 2012 ... LASSO: Other Losses (Likelihoods). https://sites.google.com/site/ eecs6898sparse2011/, 2011. [11] S. Sra, S. Nowozin, and S. J. Wright.

148

Three-Dimensional Variational Analysis with Spatially Inhomogeneous Covariances  

Science Conference Proceedings (OSTI)

In this study, a global three-dimensional variational analysis system is formulated in model grid space. This formulation allows greater flexibility (e.g., inhomogeneity and anisotropy) for background error statistics. A simpler formulation, ...

Wan-Shu Wu; R. James Purser; David F. Parrish

2002-12-01T23:59:59.000Z

149

Error Covariance Modeling in the GMAO Ocean Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

In practical applications of the ensemble Kalman filter (EnKF) for ocean data assimilation, the computational burden and memory limitations usually require a trade-off between ensemble size and model resolution. This is certainly true for the ...

Christian L. Keppenne; Michele M. Rienecker; Jossy P. Jacob; Robin Kovach

2008-08-01T23:59:59.000Z

150

Testing Proportionality in Duration Models with Respect to Continuous Covariates  

E-Print Network (OSTI)

xqhpsor|phqw ehqh#15;wv kdyh gl#14;huhqw h#14;hfwv rq wkh kd}dugv iurp xqhpsor|phqwv dv wkh vshoo ohqjwkhqv1 Pruwhqvhq +4<::, suhvhqwv vhdufk wkhruhwlf dujxphqwv rq zk| wklv vkrxog eh vr/ edvhg rq pd{lpxp ehql#15;w shulrgv/ lpso|lqj wkdw wkh lpsdfw...

Bhattacharjee, Arnab; Das, Samarjit

2004-06-16T23:59:59.000Z

151

Traceable Waveform Calibration With a Covariance-Based ...  

Science Conference Proceedings (OSTI)

... behaves when it is connected to arbitrary loads. ... pulse to determine the oscilloscope's impulse response [23]. ... would supply to an ideal 50-? load. ...

2012-10-28T23:59:59.000Z

152

Estimation of fuzzy measures using covariance matrices in Gaussian mixtures  

Science Conference Proceedings (OSTI)

This paper presents a novel computational approach for estimating fuzzy measures directly from Gaussian mixtures model (GMM). The mixture components of GMM provide the membership functions for the input-output fuzzy sets. By treating consequent part ...

Nishchal K. Verma

2012-01-01T23:59:59.000Z

153

Ocean–Atmosphere Covariability in the Western Arabian Sea  

Science Conference Proceedings (OSTI)

The western Arabian Sea exhibits strong spatial variability in sea surface temperature (SST) during the southwest monsoon, with changes in SST that can exceed 5°C over 200 km. Exploration of satellite-based and in situ data shows a strong ...

Gabriel A. Vecchi; Shang-Ping Xie; Albert S. Fischer

2004-03-01T23:59:59.000Z

154

Magnetic and antimagnetic rotation in covariant density functional theory  

Science Conference Proceedings (OSTI)

Progress on microscopic and self-consistent description of the magnetic rotation and antimagnetic rotation phenomena in tilted axis cranking relativistic mean-field theory based on a point-coupling interaction are briefly reviewed. In particular, the microscopic pictures of the shears mechanism in {sup 60}Ni and the two shears-like mechanism in {sup 105}Cd are discussed.

Zhao, P. W.; Liang, H. Z.; Peng, J.; Ring, P.; Zhang, S. Q.; Meng, J. [State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); Department of Physics, Beijing Normal University, Beijing 100875 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China) and Physik Department, Technische Universitat Muenchen, D-85747 Garching (Germany); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China); State Key Lab Nucl. Phys. and Tech., School of Physics, Peking University, Beijing 100871 (China) and Department of Physics, University of Stellenbosch, Stellenbosch (South Africa)

2012-10-20T23:59:59.000Z

155

Free Probability, Sample Covariance Matrices and Stochastic Eigen-Inference  

E-Print Network (OSTI)

Random matrix theory is now a big subject with applications in many disciplines of science, engineering and finance. This talk is a survey specifically oriented towards the needs and interests of a computationally inclined ...

Edelman, Alan

156

A Brief Practical Guide to Eddy Covariance Flux  

E-Print Network (OSTI)

........................................................................................................................... 27 Power towers for the production of mechanical work and electricity. Parabolic troughs and power towers reach peak efficiencies of parabolic troughs and power towers, thermal storage increases the annual capacity factor7 from typically 20

Noone, David

157

A Method for Estimating Potential Seasonal Predictability: Analysis of Covariance  

Science Conference Proceedings (OSTI)

This paper proposes a new method for assessing potential predictability of seasonal means using a single realization of daily time series. Potential predictability is defined as variability in seasonal means that exceeds the variability due to ...

Xia Feng; Timothy DelSole; Paul Houser

2012-08-01T23:59:59.000Z

158

Sensitivity analysis and calibration of the covariance matrix for ...  

E-Print Network (OSTI)

[Mar52] and of a generalisation of this problem taking into account the ..... thus of interest to consider model (B) above which is more realistic for stock returns on.

159

Diurnal Covariation in Soil Heat Flux and Net Radiation  

Science Conference Proceedings (OSTI)

Diurnal variation in soil heat flux is a key constraint on the amount of energy available for sensible and latent heating of the lower troposphere. Many studies have demonstrated that soil heat flux G is strongly correlated with net radiation Rn. ...

Joseph A. Santanello Jr.; Mark A. Friedl

2003-06-01T23:59:59.000Z

160

Publications  

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

38 results: 38 results: BibTex RIS RTF XML Sort by: Author Title Type [ Year (Desc) ] Filters: Author is Stephane de la Rue du Can [Clear All Filters] 2013 de la du Can, Stephane Rue, Amol Phadke, Greg Leventis, and Anand R. Gopal. A Global Review of Incentive Programs to Accelerate Energy-Efficient Appliances and Equipment., 2013. Letschert, Virginie E., Stephane Rue de la du Can, Michael A. McNeil, Puneeth Kalavase, Allison Hua Fan, and Gabrielle Dreyfus. Energy Efficiency Appliance Standards: Where do we stand, how far can we go and how do we get there? An analysis across several economies., 2013. Leventis, Greg, Anand R. Gopal, Stephane Rue de la du Can, and Amol Phadke. Avoided Electricity Subsidy Payments Can Finance Substantial Appliance Efficiency Incentive Programs: Case Study of Mexico., 2013.

Note: This page contains sample records for the topic "leventis theo covary" 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

Trajectories of Human Multi-Joint Arm Movements: Evidence of Joint Level Planning  

E-Print Network (OSTI)

the ma\\;imum-smoothncs% theoF car successfull> descti'be tne ua!ectories of human point-:o-porn: honzonta

Flanagan, Randy

162

JOM: The Member Journal of TMS - JOM Monthly  

Science Conference Proceedings (OSTI)

Sep 22, 2012 ... Theo was born in Untereggen Switzerland in 1947, the second of four children of Joseph Lehner, a landscape architect, and his wife, Clara.

163

Working but Poor: Mexican Immigrant Workers in a Low-Income Enclave in San Jose  

E-Print Network (OSTI)

formal and informal jobs that havc cspanded in the Siliconimprovement programs that havc bcen dcvcloped to address theo f the economic changes that havc occurred in Santa Clara

Zlolniski, Christian; Palerm, Juan-Vicente

1996-01-01T23:59:59.000Z

164

Multiobjective DC Programming with Infinite Convex Constraints ?  

E-Print Network (OSTI)

1 Business Link, Singapore 117592. 3. School of ... dual problems are presented and the weak, strong and strict converse duality theo- rems are also derived.

165

Arentze, Rasouli and Timmermans 1 Integrating a Multi-Agent Model of Land Development and an Activity-Based Model of  

E-Print Network (OSTI)

on Integrated Travel Demand and Network Supply Modeling, Tampa, USA. Theo Arentze, Soora Rasouli and Harry and an Activity-Based Model of Transport Demand: Progress and Developments1 Theo Arentze, Soora Rasouli and Harry aimed at integrating activity-based models of transport demand and models of land development

Kemner, Ken

166

Can Wavelets Improve the Representation of Forecast Error Covariances in Variational Data Assimilation?  

Science Conference Proceedings (OSTI)

Two wavelet-based control variable transform schemes are described and are used to model some important features of forecast error statistics for use in variational data assimilation. The first is a conventional wavelet scheme and the other is an ...

Ross N. Bannister

2007-02-01T23:59:59.000Z

167

The Behavior of Forecast Error Covariances for a Kalman Filter in Two Dimensions  

Science Conference Proceedings (OSTI)

A Kalman filter algorithm is implemented for a linearized shallow-water model over the continental United States. It is used to assimilate simulated data from the existing radiosonde network, from the demonstration network of 31 Doppler wind ...

Stephen E. Cohn; David F. Parrish

1991-08-01T23:59:59.000Z

168

Covariability of Spring Snowpack and Summer Rainfall across the Southwest United States  

Science Conference Proceedings (OSTI)

Interannual fluctuations of observed summer rainfall across the monsoon region of the southwestern United States are analyzed to ascertain their spatial coherence and to test the hypothesis that antecedent spring snowpack anomalies may modulate ...

David S. Gutzler

2000-11-01T23:59:59.000Z

169

Covariability of Surface Wind and Stress Responses to Sea Surface Temperature Fronts  

Science Conference Proceedings (OSTI)

The responses of surface wind and wind stress to spatial variations of sea surface temperature (SST) are investigated using satellite observations of the surface wind from the Quick Scatterometer (QuikSCAT) and SST from the Advanced Microwave ...

Larry W. O’Neill; Dudley B. Chelton; Steven K. Esbensen

2012-09-01T23:59:59.000Z

170

Morphology of Bluntnose Minnow Pimephales Notatus (Cyprinidae) Covaries with Habitat in a Central  

E-Print Network (OSTI)

that includes the majority of eastern North America (Page and Burr, 1991) and is a native cosmopolitan species, leading to the cosmopolitan distribution of such species as bluntnose minnow. However, a caveat

Pyron, Mark

171

Robust Ensemble Filtering and Its Relation to Covariance Inflation in the Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

A robust ensemble filtering scheme based on the H? filtering theory is proposed. The optimal H? filter is derived by minimizing the supremum (or maximum) of a predefined cost function, a criterion different from the minimum variance used in the ...

Xiaodong Luo; Ibrahim Hoteit

2011-12-01T23:59:59.000Z

172

Optimal Estimation of Spherical Harmonic Components from a Sample with Spatially Nonuniform Covariance Statistics  

Science Conference Proceedings (OSTI)

An optimal estimation technique is presented to estimate spherical harmonic coefficients. This technique is based on the minimization of the mean square error. This optimal estimation technique consists of computing optimal weights for a given ...

Kwang-Y. Kim; Gerald R. North; Samuel S. Shen

1996-03-01T23:59:59.000Z

173

Multidecadal Covariability of North Atlantic Sea Surface Temperature, African Dust, Sahel Rainfall, and Atlantic Hurricanes  

E-Print Network (OSTI)

, and Atlantic Hurricanes CHUNZAI WANG NOAA/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida for Marine and Atmospheric Studies, University of Miami, Miami, Florida AMATO T. EVAN Department/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida SANG-KI LEE NOAA/Atlantic Oceanographic

Lee, Sang-ki

174

Multidecadal Covariability of North Atlantic Sea Surface Temperature, African Dust, Sahel Rainfall, and Atlantic Hurricanes  

Science Conference Proceedings (OSTI)

Most studies of African dust and North Atlantic climate have been limited to the short time period since the satellite era (1980 onward), precluding the examination of their relationship on longer time scales. Here a new dust dataset with the ...

Chunzai Wang; Shenfu Dong; Amato T. Evan; Gregory R. Foltz; Sang-Ki Lee

2012-08-01T23:59:59.000Z

175

Eddy Covariance Measurements with Closed-Path Optical Humidity Sensors: A Feasible Concept?  

Science Conference Proceedings (OSTI)

Humidity spectra obtained with a closed-path optical hygrometer (LI-6262) show an apparent low-pass characteristic with a cutoff frequency varying between 0.01 and 0.1 Hz. Laboratory measurements revealed that contamination of the intake filter ...

Gerhard Peters; Bernd Fischer; Hans Münster

2001-04-01T23:59:59.000Z

176

Human action recognition using a temporal hierarchy of covariance descriptors on 3D joint locations  

Science Conference Proceedings (OSTI)

Human action recognition from videos is a challenging machine vision task with multiple important application domains, such as human-robot/machine interaction, interactive entertainment, multimedia information retrieval, and surveillance. In this paper, ...

Mohamed E. Hussein, Marwan Torki, Mohammad A. Gowayyed, Motaz El-Saban

2013-08-01T23:59:59.000Z

177

Tests of homogeneity of means and covariance matrices for multivariate incomplete data  

E-Print Network (OSTI)

tt4T|L? c|i @hLt4i@? t| it|ttL*_TihuLh4i^@*i? |*)54*@h*)c|iUL@h@? Ui4@|h |it|ttL*_ TihuLh4i^@*i? |*)c@ttL*_|iUL4M?h@M*iuhL4|i@hLtti|tLu tMiU|ttL*_Miit|4@|itLu|it@4iTLT*@|L?

Kevin H. Kim; Peter M. Bentler

2011-01-01T23:59:59.000Z

178

Using Improved Background-Error Covariances from an Ensemble Kalman Filter for Adaptive Observations  

Science Conference Proceedings (OSTI)

A method for determining adaptive observation locations is demonstrated. This method is based on optimal estimation (Kalman filter) theory; it determines the observation location that will maximize the expected improvement, which can be measured ...

Thomas M. Hamill; Chris Snyder

2002-06-01T23:59:59.000Z

179

Impact of Covariance Localization on Ensemble Estimation of Surface Downwelling Longwave and Shortwave Radiation Fluxes  

Science Conference Proceedings (OSTI)

Accurate estimates of terrestrial hydrologic states and fluxes are, in large part, dependent on accurate estimates of the spatiotemporal variability and uncertainty of land surface forcings, including downwelling longwave (LW) and shortwave (SW) ...

B. A. Forman; S. A. Margulis

2012-08-01T23:59:59.000Z

180

Two-spinors, oscillator algebras, and qubits: aspects of manifestly covariant approach to relativistic quantum information  

Science Conference Proceedings (OSTI)

The first part of the paper reviews applications of 2-spinor methods to relativistic qubits (analogies between tetrads in Minkowski space and 2-qubit states, qubits defined by means of null directions and their role for elimination of the Peres-Scudo-Terno ... Keywords: Quantization, Qubits, SL(2,C), Two-spinors

Marek Czachor

2010-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Error Covariance Matrices Characterization in the Ocean Salinity Retrieval Cost Function within the SMOS Mission  

Science Conference Proceedings (OSTI)

The interests of the scientific community working on the Soil Moisture and Ocean Salinity (SMOS) ocean salinity level 2 processor definition are currently focused on improving the performance of the retrieval algorithm, which is based on an ...

M. Talone; C. Gabarró; A. Camps; R. Sabia; J. Gourrion; M. Vall-llossera; J. Font

2011-09-01T23:59:59.000Z

182

Estimation of Three-Dimensional Error Covariances. Part II: Analysis of Wind Innovation Vectors  

Science Conference Proceedings (OSTI)

The method of statistical analysis of wind innovation (observation minus forecast) vectors is refined upon the work of Hollingsworth and Lönnberg (HL). The new refinements include (i) improved spectral representations of wind forecast error ...

Qin Xu; Li Wei

2001-12-01T23:59:59.000Z

183

A fully covariant mean-field dynamo closure for numerical 3+1 resistive GRMHD  

E-Print Network (OSTI)

The powerful high-energy phenomena typically encountered in astrophysics invariably involve physical engines, like neutron stars and black hole accretion disks, characterized by a combination of highly magnetized plasmas, strong gravitational fields, and relativistic motions. In recent years numerical schemes for General Relativistic MHD (GRMHD) have been developed to model the multidimensional dynamics of such systems, including the possibility of an evolving spacetime. Such schemes have been also extended beyond the ideal limit including the effects of resistivity, in an attempt to model dissipative physical processes acting on small scales (sub-grid effects) over the global dynamics. Along the same lines, magnetic fields could be amplified by the presence of turbulent dynamo processes, as often invoked to explain the high values of magnetization required in accretion disks and neutron stars. Here we present, for the first time, a further extension to include the possibility of a mean-field dynamo action wi...

Bucciantini, N

2012-01-01T23:59:59.000Z

184

Eddy covariance mapping and quantification of surface CO2 leakage fluxes  

E-Print Network (OSTI)

layer model for heavy gas dispersion from natural sources:Numerical model of gas dispersion emitted from volcanic

Lewicki, J.L.

2010-01-01T23:59:59.000Z

185

Covariability of Components of Poleward Atmospheric Energy Transports on Seasonal and Interannual Timescales  

Science Conference Proceedings (OSTI)

Vertically integrated atmospheric energy and heat budgets are presented with a focus on the zonal mean transports and divergences of dry static energy, latent energy, their sum (the moist static energy), and the total (which includes kinetic ...

Kevin E. Trenberth; David P. Stepaniak

2003-11-01T23:59:59.000Z

186

Resilience of Hybrid Ensemble/3DVAR Analysis Schemes to Model Error and Ensemble Covariance Error  

Science Conference Proceedings (OSTI)

Previous idealized numerical experiments have shown that a straightforward augmentation of an isotropic error correlation matrix with an ensemble-based error correlation matrix yields an improved data assimilation scheme under certain conditions. ...

Brian J. Etherton; Craig H. Bishop

2004-05-01T23:59:59.000Z

187

Another look at general covariance and the equivalence of reference frames  

E-Print Network (OSTI)

for the History and Foundations of Science Utrecht University, P.O.Box 80.000 3508 TA Utrecht, The Netherlands toward the front of their bowl with no more effort than toward the back . . . the butterflies and flies

Seevinck, Michiel

188

Estimating Model-Error Covariances for Application to Atmospheric Data Assimilation  

Science Conference Proceedings (OSTI)

Forecast-error statistics have traditionally been used to investigate model performance and to calculate analysis weights for atmospheric data assimilation. Forecast error has two components: the model error, caused by model imperfections, and ...

Roger Daley

1992-08-01T23:59:59.000Z

189

Design of the AmeriFlux Portable Eddy Covariance System and Uncertainty Analysis of Carbon Measurements  

Science Conference Proceedings (OSTI)

The AmeriFlux network continues to improve the understanding of carbon, water, and energy fluxes across temporal and spatial scales. The network includes 120 research sites that contribute to the understanding of processes within and among ...

T. W. Ocheltree; H. W. Loescher

2007-08-01T23:59:59.000Z

190

Implications and mitigation of model mismatch and covariance contamination for hyperspectral chemical agent detection  

E-Print Network (OSTI)

Most chemical gas detection algorithms for long-wave infrared hyperspectral images assume a gas with a perfectly known spectral signature. In practice, the chemical signature is either imperfectly measured and/or exhibits ...

Niu, Sidi

191

An Analysis of Closures for Pressure-Scalar Covariances in the Convective Boundary Layer  

Science Conference Proceedings (OSTI)

Perhaps the most commonly used closure in second-moment models of turbulence is Rotta's return-to-isotropy expression, which was originally developed to pararmeterize the pressure-velocity gradient correlation in the Reynolds stress conservation ...

Chin-Hoh Moeng; John C. Wyngaard

1986-11-01T23:59:59.000Z

192

Schwarzschild Solution of the Generally Covariant Quaternionic Field Equations of Sachs  

E-Print Network (OSTI)

Sachs has derived quaternion field equations that fully exploit the underlying symmetry of the principle of general relativity, one in which the fundamental 10 component metric field is replaced by a 16 component four-vector quaternion. Instead of the 10 field equations of Einstein's tensor formulation, these equations are 16 in number corresponding to the 16 analytic parametric functions {\\partial}x^{{\\mu}'}/{\\partial}x^{{\

Horace W. Crater; Jesse Labello; Steve Rubenstein

2010-10-18T23:59:59.000Z

193

MOTOR-VEHICLE INFRASTRUCTURE AND SERVICES PROVIDED BY THE PUBLIC SECTOR Report #7 in the series: The Annualized Social Cost of Motor-Vehicle Use in the United States, based on 1990-1991 Data  

E-Print Network (OSTI)

OIL - HOLDING COSTS .AND MANAGEMENT, AND OIL-HOLDING COSTS 7.12.1 Background TheO & M costs, and oil–holding costs -- can be estimated from

Delucchi, Mark

2005-01-01T23:59:59.000Z

194

Motor-Vehicle Infrastructure and Services Provided by the Public Sector: Report #7 in the series: The Annualized Social Cost of Motor-Vehicle Use in the United States, based on 1990-1991 Data  

E-Print Network (OSTI)

OIL - HOLDING COSTS .AND MANAGEMENT, AND OIL-HOLDING COSTS 7.12.1 Background TheO & M costs, and oil–holding costs -- can be estimated from

Delucchi, Mark; Murphy, James

2005-01-01T23:59:59.000Z

195

Zhengji Zhao  

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

Zhengji Zhao , Lin-Wang Wang, and Fengmin Wu, "Wavefunction localizations in bulged CdSe nanowires", J. of Comp. and Theo. Nano., pp.247-251, vol.4, no. 2, (2007)., July 2,...

196

Tru st r egion algo r ithms a r e classical methods fo r solving both ...  

E-Print Network (OSTI)

Dec 8, 2004 ... T he following theo r em p r ovides an efficient app r oach to comp u te the vecto r ufo r dealing with the ha r d case te r mination in step3) of ...

197

Toward a consistency cross-check of eddy covariance flux–based and biometric estimates of ecosystem carbon balance  

E-Print Network (OSTI)

estimates of annual carbon sequestration in a Sitka spruce (carbon cycling in a temperate forest: Radiocarbon-based estimates of residence times, sequestration

2009-01-01T23:59:59.000Z

198

Error Covariance Estimation for Coupled Data Assimilation Using a Lorenz Atmosphere and a Simple Pycnocline Ocean Model  

Science Conference Proceedings (OSTI)

Coupled data assimilation uses a coupled model consisting of multiple time-scale media to extract information from observations that are available in one or more media. Because of the instantaneous exchanges of information among the coupled media, ...

Guijun Han; Xinrong Wu; Shaoqing Zhang; Zhengyu Liu; Wei Li

2013-12-01T23:59:59.000Z

199

ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data  

E-Print Network (OSTI)

in part by the U.S. Department of Energy/NNSA Na-22 Office under Grant No. DE-FG03-01NN20122. The authors

Danon, Yaron

200

Error Covariance Estimation for Coupled Data Assimilation Using a Lorenz Atmosphere and a Simple Pycnocline Ocean Model  

Science Conference Proceedings (OSTI)

Coupled data assimilation uses a coupled model consisting of multiple time scale media to extract information from observations that are available in one or more media. Due to instantaneous exchanges of information among the coupled media, coupled ...

Guijun Han; Xinrong Wu; Shaoqing Zhang; Zhengyu Liu; Wei Li

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to obtain the most current and comprehensive results.


201

Impact of Flow Dependence, Column Covariance, and Forecast Model Type on Surface-Observation Assimilation for Probabilistic PBL Profile Nowcasts  

Science Conference Proceedings (OSTI)

A probabilistic verification and factor-separation analysis (FSA) elucidate skillful nowcasts of planetary boundary layer (PBL) temperature, moisture, and wind profiles with a single-column model (SCM) and ensemble filter (EF) assimilation of ...

Dorita Rostkier-Edelstein; Joshua P. Hacker

2013-02-01T23:59:59.000Z

202

Incorporating State-Dependent Temperature–Salinity Constraints in the Background Error Covariance of Variational Ocean Data Assimilation  

Science Conference Proceedings (OSTI)

Several studies have illustrated how the univariate assimilation of temperature data can have a detrimental effect on the ocean-state variables (salinity, currents, etc.) not directly constrained by the data. In this paper, the authors describe ...

S. Ricci; A. T. Weaver; J. Vialard; P. Rogel

2005-01-01T23:59:59.000Z

203

Chapter 16: The Analysis of Covariance In some experiments, the experimental units are nonhomogeneous or there is variation in the  

E-Print Network (OSTI)

may have an undue influence on the outcome of the trial. 1 #12;Table 1: Peanut plant growth data in increased precision for parameter estimates and increased power for tests of hypotheses. In Chapter 15, we (S) and a fast- release fertilizer (F), on seed yields (grams) of peanut plant were compared

Liang, Faming

204

Examination of Situation-Dependent Background Error Covariances at the Convective Scale in the Context of the Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

A high-resolution ensemble Kalman filter (HREnKF) system at the convective scale has been developed based on the Canadian Meteorological Center's operational global ensemble Kalman filter (EnKF) system. This study focuses on the very early stage ...

Kao-Shen Chung; Weiguang Chang; Luc Fillion; Monique Tanguay

2013-10-01T23:59:59.000Z

205

Comparing Aircraft-Based Remotely Sensed Energy Balance Fluxes with Eddy Covariance Tower Data Using Heat Flux Source Area Functions  

Science Conference Proceedings (OSTI)

In an effort to better evaluate distributed airborne remotely sensed sensible and latent heat flux estimates, two heat flux source area (footprint) models were applied to the imagery, and their pixel weighting/integrating functionality was ...

JoséL. Chávez; Christopher M. U. Neale; Lawrence E. Hipps; John H. Prueger; William P. Kustas

2005-12-01T23:59:59.000Z

206

Efficient Parameterization of the Observation Error Covariance Matrix for Square Root or Ensemble Kalman Filters: Application to Ocean Altimetry  

Science Conference Proceedings (OSTI)

In the Kalman filter standard algorithm, the computational complexity of the observational update is proportional to the cube of the number y of observations (leading behavior for large y). In realistic atmospheric or oceanic applications, ...

Jean-Michel Brankart; Clément Ubelmann; Charles-Emmanuel Testut; Emmanuel Cosme; Pierre Brasseur; Jacques Verron

2009-06-01T23:59:59.000Z

207

Comparison of Model-Produced and Observed Microwave Radiances and Estimation of Background Error Covariances for Hydrometeor Variables within Hurricanes  

Science Conference Proceedings (OSTI)

A radiative transfer model was updated to better simulate Special Sensor Microwave Imager (SSM/I)–observed brightness temperatures in areas of high ice concentration. The difference between the lowest observed and model-produced brightness ...

Clark Amerault; Xiaolei Zou

2006-03-01T23:59:59.000Z

208

A Study of the Error Covariance Matrix of Radar Rainfall Estimates in Stratiform Rain. Part II: Scale Dependence  

Science Conference Proceedings (OSTI)

The contribution of various physical sources of uncertainty affecting radar rainfall estimates at the ground has been recently quantified at a resolution typically used in schemes assimilating rainfall at the ground onto mesoscale models. Here, ...

Marc Berenguer; Isztar Zawadzki

2009-06-01T23:59:59.000Z

209

Numerical Aspects of the Application of Recursive Filters to Variational Statistical Analysis. Part I: Spatially Homogeneous and Isotropic Gaussian Covariances  

Science Conference Proceedings (OSTI)

The construction and application of efficient numerical recursive filters for the task of convolving a spatial distribution of “forcing” terms with a quasi-Gaussian self-adjoint smoothing kernel in two or three dimensions are described. In the ...

R. James Purser; Wan-Shu Wu; David F. Parrish; Nigel M. Roberts

2003-08-01T23:59:59.000Z

210

Comparing nocturnal eddy covariance measurements to estimates of ecosystem respiration made by scaling chamber measurements at six coniferous boreal sites  

E-Print Network (OSTI)

Springer-Verlag, New Manitoba, J. Geophys. Res. , thisin Saskatchewan and Manitoba, Canada, Tree Physiol. , VEMAPjack pine (old) in northern Manitoba and 600, 480, and 310 g

1997-01-01T23:59:59.000Z

211

Publications  

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

30 results: 30 results: BibTex RIS RTF XML Sort by: Author Title Type [ Year (Desc) ] Filters: Author is Amol Phadke [Clear All Filters] 2013 Shah, Nihar, Paul Waide, and Amol Phadke. Cooling the Planet: Opportunities for Deployment of Superefficient Room Air Conditioners., 2013. Park, Won Young, Amol Phadke, Nihar Shah, and Virginie E. Letschert. "Efficiency Improvement Opportunities in TVs: Implications for Market Transformation Programs." Energy Policy 59 (2013): 361-372. de la du Can, Stephane Rue, Amol Phadke, Greg Leventis, and Anand R. Gopal. A Global Review of Incentive Programs to Accelerate Energy-Efficient Appliances and Equipment., 2013. Sathaye, Nakul, Amol Phadke, Nihar Shah, and Virginie E. Letschert. Potential Global Benefits of Improved Ceiling Fan Energy Efficiency., 2013.

212

Regional Pathways to Technological Upgrading: The Impact of Agglomeration Economies and its Regional Covariates on Upgrading in Post-reforms India's Manufacturing Sector  

E-Print Network (OSTI)

MODEL 1. Tech = f (Capital Intensity, Skill Intensity) MODELUsed MODEL 1. Tech = f (Capital Intensity, Skill Intensity,urban location with capital-intensity and diversity with

Mallavarapu, Bravishwar

2013-01-01T23:59:59.000Z

213

The Passage of State Fair Employment Legislation, 1945-1964: An Event-History Analysis with Time-Varying and Time-Constant Covariates  

E-Print Network (OSTI)

Innovations: An Event History Analysis. ” American PoliticalKazuo. 1991. Event History Analysis. Newbury Park, CA: Sage.Allison, Paul. 1982. Event History Analysis. Newbury Park:

Chen, Anthony S.

2001-01-01T23:59:59.000Z

214

Regional Pathways to Technological Upgrading: The Impact of Agglomeration Economies and its Regional Covariates on Upgrading in Post-reforms India's Manufacturing Sector  

E-Print Network (OSTI)

2002. “Does Economic Liberalisation Endanger Indigenous2002. “Does Economic Liberalisation Endanger Indigenous

Mallavarapu, Bravishwar

2013-01-01T23:59:59.000Z

215

Fast Lidar and Radar Multiple-Scattering Models. Part I: Small-Angle Scattering Using the Photon Variance–Covariance Method  

Science Conference Proceedings (OSTI)

A fast, approximate method is described for the calculation of the intensity of multiply scattered lidar returns from clouds. At each range gate it characterizes the outgoing photon distribution by its spatial variance, the variance of photon ...

Robin J. Hogan

2008-12-01T23:59:59.000Z

216

Spectral Analysis via the Virtual Observatory: The Service Theossa  

E-Print Network (OSTI)

In the framework of the Virtual Observatory, the newly developed service TheoSSA provides access to theoretical stellar spectral-energy distributions. In a pilot phase, this service is based on the well established Tuebingen NLTE Model-Atmosphere Package for hot, compact stars. We demonstrate its present capabilities and future extensions.

Ringat, Ellen; Werner, Klaus

2011-01-01T23:59:59.000Z

217

Revised Version DESY 96203 Hiroshima Univ. HUPD9615  

E-Print Network (OSTI)

Revised Version DESY 96­203 Hiroshima Univ. HUPD­9615 September 1996 ################ hep , and T. Morozumi x Department of Physics, Hiroshima University 1­3­1 Kagamiyama, Higashi Hiroshima ­ 7393FT­LIPI, Indonesia. E­mail address: handoko@theo.phys.sci.hiroshima­u.ac.jp x E­mail address

218

Learning to Translate with Source and Target Syntax David Chiang  

E-Print Network (OSTI)

Learning to Translate with Source and Target Syntax David Chiang USC Information Sciences Institute 4676 Admiralty Way, Suite 1001 Marina del Rey, CA 90292 USA chiang@isi.edu Abstract Statistical of these (Chiang, 2005) make no use of information from syntactic theo- ries or syntactic annotations, whereas

Chiang, David

219

Measurement of the W Boson Mass with the D0 Run II Detector using the Electron P(T) Spectrum  

SciTech Connect

This thesis is a description of the measurement of the W boson mass using the D0 Run II detector with 770 pb{sup -1} of p{bar p} collision data. These collisions were produced by the Tevatron at {radical}s = 1.96 TeV between 2002 and 2006. We use a sample of W {yields} e{nu} and Z {yields} ee decays to determine the W boson mass with the transverse momentum distribution of the electron and the transverse mass distribution of the boson. We measure M{sub W} = XXXXX {+-} 37 (stat.) {+-} 26 (sys. theo.) {+-} 51 (sys. exp.) MeV = XXXXX {+-} 68 MeV with the transverse momentum distribution of the electron and M{sub W} = XXXXX {+-} 28 (stat.) {+-} 17 (sys. theo.) {+-} 51 (sys. exp.) MeV = XXXXX {+-} 61 MeV with the transverse mass distribution.

Andeen, Timothy R., Jr.; /Northwestern U.

2008-06-01T23:59:59.000Z

220

Abstract for Elmar Biernat  

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

consider two different manifestly covariant approaches to mesons, Point-Form Quantum Mechanics (PFQM) and the Covariant Spectator Theory (CST). In the first part of my seminar I...

Note: This page contains sample records for the topic "leventis theo covary" 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

A Review of Two different Approaches for the Analysis of Growth Data Using Longitudinal Mixed Linear Models: Comparing Hierarchical Linear Regression (ML3), HLM) and Repeated Measures Designs with Structured Covariance Matrices (BMDP5V)  

E-Print Network (OSTI)

analyses involving very large data sets. ML3/E is especially compiled for personal computers with expanded RAM (

Rien van der Leeden; Karen Vrijburg; Jan de Leeuw

2011-01-01T23:59:59.000Z

222

FINAL REPORT: EDDY-COVARIANCE FLUX TOWER AND TRACER TECHNOLOGY SUPPORT FOR THE UNIVERSITY OF GEORGIA PROPOSAL: FROM TOWER TO PIXEL: INTEGRATION OF PATCH-SIZE NEE USING EXPERIMENTAL MODELING FOOTPRINT ANALYSIS.  

SciTech Connect

Brookhaven National Laboratory has been funded since October of 2000 to provide assistance to the University of Georgia in conducting footprint analyses of individual towers based on meteorology and trace gas measurements. Brookhaven researchers conducted air flow measurements using perfluorocarbon tracers and meteorological instrumentation for three experimental campaigns at an AmeriFlux research site maintained by Dr. Monique Leclerc near Gainesville, FL. In addition, BNL provided assistance with remote data collection and distribution from remote field sites operated by Dr. John Hom of the US Forest Service in the Pine Barrens of New Jersey and at FACE research sites in North Carolina and Wisconsin.

LEWIN,K.F.; NAGY, J.; WATSON, T.B.

2007-09-01T23:59:59.000Z

223

Citation: K. Hagiwara  

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

b b I (J P ) = 0( 1 2 + ) Charge = - 1 3 e Bottom = -1 b-QUARK MASS b-QUARK MASS b-QUARK MASS b-QUARK MASS The b-quark mass is estimated from bottomonium and B masses. It cor- responds to the "running" mass m b (µ = m b ) in the MS scheme. We have converted masses in other schemes to the MS scheme using two-loop QCD pertubation theory with α s (µ=m b ) = 0.22. The range 4.0-4.5 GeV for the MS mass corresponds to 4.6-5.1 GeV for the pole mass (see the "Note on Quark Masses"). VALUE (GeV) DOCUMENT ID TECN COMMENT 4.0 to 4.5 OUR EVALUATION 4.0 to 4.5 OUR EVALUATION 4.0 to 4.5 OUR EVALUATION 4.0 to 4.5 OUR EVALUATION * * * We do not use the following data for averages, fits, limits, etc. * * * 3.95 ± 0.57 1 ABBIENDI 01S OPAL MS scheme 4.21 ± 0.05 2 KUHN 01 THEO MS scheme 4.05 ± 0.06 3 NARISON 01B THEO MS scheme 4.7 ± 0.74 4 BARATE 00V ALEP MS scheme 4.20 ± 0.06 5 HOANG 00 THEO MS scheme 4.437 + 0.045 - 0.029 6 LUCHA

224

Protocol for SAMS (Support and Advice for Medication Study): a randomised controlled trial of an intervention to support patients with type 2 diabetes with adherence to medication  

E-Print Network (OSTI)

Psychol 1999, 29:349-369. 16. Ajzen I: The theory of planned behaviour. Organizational Behavior and Human Decision Processes 1991, 50:179-211. 17. Sutton S: Determinants of health-related behaviours: Theo- retical and methodological issues. In The Sage... J Farmer*1, A Toby Prevost2, Wendy Hardeman2, Anthea Craven1, Stephen Sutton2, Simon J Griffin3, Ann-Louise Kinmonth2 for The Support and Advice for Medication Trial Group Address: 1Department of Primary Health Care, University of Oxford, Oxford...

Farmer, Andrew J; Prevost, A Toby; Hardeman, Wendy; Craven, Anthea; Sutton, Stephen; Griffin, Simon J; Kinmonth, Ann Louise; (sams), Support and Advice for Medication Study

2008-04-11T23:59:59.000Z

225

Localization and Sampling Error Correction in Ensemble Kalman Filter Data Assimilation  

Science Conference Proceedings (OSTI)

Ensemble Kalman filters use the sample covariance of an observation and a model state variable to update a prior estimate of the state variable. The sample covariance can be suboptimal as a result of small ensemble size, model error, model ...

Jeffrey L. Anderson

2012-07-01T23:59:59.000Z

226

Climate Response Using a Three-Dimensional Operator Based on the Fluctuation–Dissipation Theorem  

Science Conference Proceedings (OSTI)

The fluctuation–dissipation theorem (FDT) states that for systems with certain properties it is possible to generate a linear operator that gives the response of the system to weak external forcing simply by using covariances and lag-covariances ...

Andrey Gritsun; Grant Branstator

2007-07-01T23:59:59.000Z

227

Detection and Analysis of Microfronts and Associated Coherent Events Using Localized Transforms  

Science Conference Proceedings (OSTI)

A general localized transforms is used to study the characteristics of conditional sampling techniques. A covariance transform is defined that measures the covariance between the signal and a dilated and translated generating function which has ...

Nimal Gamage; Carl Hagelberg

1993-03-01T23:59:59.000Z

228

Perturbation Growth and Structure in Uncertain Flows. Part II  

Science Conference Proceedings (OSTI)

Perturbation growth in uncertain systems associated with fluid flow is examined concentrating on deriving, solving, and interpreting equations governing the ensemble mean covariance. Covariance evolution equations are obtained for fluctuating ...

Brian F. Farrell; Petros J. Ioannou

2002-09-01T23:59:59.000Z

229

Comparison of Hybrid Ensemble/4DVar and 4DVar within the NAVDAS-AR Data Assimilation Framework  

Science Conference Proceedings (OSTI)

The effect on weather forecast performance of incorporating ensemble covariances into the initial covariance model of the four-dimensional variational data assimilation (4D-Var) Naval Research Laboratory Atmospheric Variational Data Assimilation ...

David D. Kuhl; Thomas E. Rosmond; Craig H. Bishop; Justin McLay; Nancy L. Baker

2013-08-01T23:59:59.000Z

230

On the Influence of Random Wind Stress Errors on the Four-Dimensional, Midlatitude Ocean Inverse Problem  

Science Conference Proceedings (OSTI)

The effects of the parameterized wind stress error covariance function on the a priori error covariance of an ocean general circulation model (OGCM) are examined. These effects are diagnosed by computing the projection of the a priori model state ...

Tsuyoshi Wakamatsu; Michael G. G. Foreman; Patrick F. Cummins; Josef Y. Cherniawsky

2009-06-01T23:59:59.000Z

231

Error Estimates for an Ocean General Circulation Model from Altimeter and Acoustic Tomography Data  

Science Conference Proceedings (OSTI)

An offline approach is proposed for the estimation of model and data error covariance matrices whereby covariance matrices of model data residuals are “matched” to their theoretical expectations using familiar least-squares methods. This ...

Dimitris Menemenlis; Michael Chechelnitsky

2000-03-01T23:59:59.000Z

232

Statistical Tests of Taylor’s Hypothesis: An Application to Precipitation Fields  

Science Conference Proceedings (OSTI)

The Taylor hypothesis (TH) as applied to rainfall is a proposition about the space–time covariance structure of the rainfall field. Specifically, it supposes that if a spatiotemporal precipitation field with a stationary covariance Cov(r, ?) in ...

Bo Li; Aditya Murthi; Kenneth P. Bowman; Gerald R. North; Marc G. Genton; Michael Sherman

2009-02-01T23:59:59.000Z

233

Retrieval of Moisture from Simulated GPS Slant-Path Water Vapor Observations Using 3DVAR with Anisotropic Recursive Filters  

Science Conference Proceedings (OSTI)

Anisotropic recursive filters are implemented within a three-dimensional variational data assimilation (3DVAR) framework to efficiently model the effect of flow-dependent background error covariance. The background error covariance is based on an ...

Haixia Liu; Ming Xue; R. James Purser; David F. Parrish

2007-04-01T23:59:59.000Z

234

Orthogonal Rotation of Spatial Patterns Derived from Singular Value Decomposition Analysis  

Science Conference Proceedings (OSTI)

Singular value decomposition (SYD) analysis is frequently used to identify pairs of spatial patterns whose time series are characterized by maximum temporal covariance. It tends to compress complicated temporal covariance between two fields into ...

Xinhua Cheng; Timothy J. Dunkerton

1995-11-01T23:59:59.000Z

235

What's Inside . . . Fire effects database  

E-Print Network (OSTI)

/climate Analysis of inadvertent microprocessor lag time on eddy covariance results. Zeller, Karl; Zimmerman, Gary;Hehn,Ted;Donev

236

Particle Energy Spectrum, Revisited from a Counting Statistics Perspective  

SciTech Connect

This document is a slide show type presentation of a new covariance estimation for gamma spectra and neutron cross section.

Yuan, D., Marks, D. G., Guss, P. P.

2012-07-16T23:59:59.000Z

237

Electric Dipole Polarizability in ${}^{208}$Pb: insights from the Droplet Model  

E-Print Network (OSTI)

We study the electric dipole polarizability $\\alpha_D$ in ${}^{208}$Pb based on the predictions of a large and representative set of relativistic and non-relativistic nuclear mean field models. We adopt the droplet model as a guide to better understand the correlations between $\\alpha_D$ and other isovector observables. Insights from the droplet model suggest that the product of $\\alpha_D$ and the nuclear symmetry energy at saturation density $J$ is much better correlated with the neutron skin thickness $\\Delta r_{np}$ of ${}^{208}$Pb than the polarizability alone. Correlations of $\\alpha_D J$ with $\\Delta r_{np}$ and with the symmetry energy slope parameter $L$ suggest that $\\alpha_D J$ is a strong isovector indicator. Hence, we explore the possibility of constraining the isovector sector of thenuclear energy density functional by comparing our theoretical predictions against measurements of both $\\alpha_D$ and the parity-violating asymmetry in ${}^{208}$Pb. We find that the recent experimental determination of $\\alpha_D$ in ${}^{208}$Pb in combination with the range for the symmetry energy at saturation density $J=[31\\pm (2)_{\\rm est.}]$\\,MeV suggests $\\Delta r_{np}({}^{208}{\\rm Pb}) = 0.165 \\pm (0.009)_{\\rm exp.} \\pm (0.013)_{\\rm theo.} \\pm (0.021)_{\\rm est.} {\\rm fm}$ and $L= 43 \\pm(6)_{\\rm exp.} \\pm (8)_{\\rm theo.}\\pm(12)_{\\rm est.}$ MeV.

X. Roca-Maza; M. Centelles; X. Viñas; M. Brenna; G. Colò; B. K. Agrawal; N. Paar; J. Piekarewicz; D. Vretenar

2013-07-17T23:59:59.000Z

238

Particles, superparticles, and twistors  

Science Conference Proceedings (OSTI)

The covariant Green-Schwarz action for a superstring has never been quantized covariantly. The physics behind this is discussed. We then consider the corresponding point-particle action in four dimensions, and write down a master action from which it can be obtained as a gauge choice: the ''space-time gauge.'' There is also a ''twistor gauge,'' in which covariant quantization is straightforward (as noted previously by Shirafuji).

Bengtsson, A.K.H.; Bengtsson, I.; Cederwall, M.; Linden, N.

1987-09-15T23:59:59.000Z

239

Theory Seminar Schedule  

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

6-2007 6-2007 Click on a title to read an abstract, if available (underlined). 10 July 2007 Special Day: Tuesday, 3:00pm Robert Wiringa Argonne National Laboratory wiringa@theory.phy.anl.gov Dependence of nuclear binding on hadronic mass variation 3 July 2007 Special Day and Time: Tuesday, 10:30am Renato Higa University of Bonn, Germany higa@itkp.uni-bonn.de Coulomb interactions within Halo EFT 5 June 2007 Special Day and Time: Tuesday, 10.30am Omar Benhar Istituto Nazionale di Fisica Nucleare, Rome, Italy benhar@roma1.infn.it The equation of state of neutron star matter and gravitational wave emission 29 May 2007 Special Day: Tuesday Ulrich Mosel Giessen University, Germany Ulrich.Mosel@theo.physik.uni-giessen.de Hadrons in Medium - Theory meets experiment 10 May 2007

240

Argonne Physics Division - Theory Group  

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

Seminars held in the year 2008-2009 Seminars held in the year 2008-2009 Click on a title to read an abstract, if available (underlined). 23 July 2009 Ulrich Mosel University of Giessen Ulrich.Mosel@theo.physik.uni-giessen.de Hadrons in Medium 4 June 2009 Arnoldas Deltuva University of Lisbon deltuva@cii.fc.ul.pt Three- and four-body nuclear reactions 2 June 2009 Special Day: Tuesday Yasuyuki Suzuki Niigata University suzuki@nt.sc.niigata-u.ac.jp Phase-shift calculation using continuum-discretized states 13 May 2009 Special Day: Wednesday William Detmold College of William & Mary and Jefferson Lab wdetmold@wm.edu Many-body lattice QCD 23 April 2009 Shalom Shlomo Cyclotron Institut Texas A&M University, College Station shlomo@comp.tamu.edu Modern energy density functional for nuclei and the nuclear matter Equation of State

Note: This page contains sample records for the topic "leventis theo covary" 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

vcb_vub_s052205-web.dvi  

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

J. J. Beringer et al. (Particle Data Group), PR D86, 010001 (2012) (URL: http://pdg.lbl.gov) June 18, 2012 15:24 - 2- measured in regions previously considered inaccessible, increas- ing the acceptance for B → X u ℓν ℓ transitions and reducing theoretical uncertainties. Experimental measurements of the exclusive B → πℓν ℓ decay are quite precise, and recent improvements in the theo- retical calculation of the form factor normalization have enabled a determination of |V ub | from this decay with an uncertainty below 10%. Throughout this review the numerical results quoted are based on the methods of the Heavy Flavor Averaging Group [2]. DETERMINATION OF |V cb | Summary: The determination of |V cb | from B → D ∗ ℓν ℓ decays is currently at a relative precision of about 2%. The main limitation is the knowledge of the form factor near the maximum momentum transfer to the

242

Abstract for Brian Serot  

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

theory for nuclei Recent progress in Lorentz-covariant quantum field theories of the nuclear many-body problem (quantum hadrodynamics, or QHD) is discussed. The effective field...

243

Abstract for Jorge Martin Camalich  

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

Jorge Martin Camalich University of Valencia Properties of hyperons in covariant chiral perturbation theory We present some recent progress on the understanding of the...

244

Multiple Imputation for Threshold-Crossing Data with Interval Censoring  

E-Print Network (OSTI)

A. ‘Incomplete data in event history analysis’, in Trussell,Applications of Event History Analysis, Clarendon Press,covariate in the analysis of a subsequent event. This paper

Fredierick J. Dorey; Roderick J.A. Little; Nathaniel Schenker

2011-01-01T23:59:59.000Z

245

Abstract for Alessandro Lovato  

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

Argonne Leadership Computing Facility and Physics Division Meson properties from two different covariant approaches The Fermi and Gamow-Teller responses of cold symmetric nuclear...

246

Position and momentum observables on R and on R^3  

E-Print Network (OSTI)

We characterize all position and momentum observables on R and on R^3. We study some of their operational properties and discuss their covariant joint observables.

C. Carmeli; T. Heinonen; A. Toigo

2004-03-15T23:59:59.000Z

247

Face and Iris Testing  

Science Conference Proceedings (OSTI)

... framework completed and applied to covariate and quality analysis on FRVT & ... to be submitted to journal). DHS/US-VISIT scenario and technology ...

2010-10-05T23:59:59.000Z

248

b096.dvi  

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

6 6 Z 0 (1865) 3/2 - I (J P ) = 0( 3 2 - ) Status: ∗ OMITTED FROM SUMMARY TABLE This effect is strongly associated with the N K ∗ threshold. See also NODE=B096 the Z 0 (1780). Z 0 (1865) MASS Z 0 (1865) MASS Z 0 (1865) MASS Z 0 (1865) MASS NODE=B096M NODE=B096M VALUE (MeV) DOCUMENT ID TECN COMMENT 1907 NAKAJIMA 82B PWA K N 0.2-1.6 GeV/c 1830 AARON 73 MPWA Isospin-0 K N 0.6-1.6 GeV/c 1840 1 CARROLL 73B CNTR K N I = 0 total σ (fit 2) 1868 ± 10 COOL 70 CNTR K + p, K + d total σ 1860 ± 15 CARTER 67 THEO Dispersion relation Z 0 (1865) WIDTH Z 0 (1865) WIDTH Z 0 (1865) WIDTH Z 0 (1865) WIDTH NODE=B096W NODE=B096W VALUE (MeV) DOCUMENT ID TECN COMMENT 291 NAKAJIMA 82B PWA K N 0.2-1.6 GeV/c 100 AARON 73 MPWA Isospin-0 K N 0.6-1.6 GeV/c 75 1 CARROLL 73B CNTR K N I = 0 total σ (fit 2) 160 ± 30 COOL 70 CNTR 200 ± 50 CARTER 67 THEO Z 0 (1865) DECAY MODES Z 0 (1865) DECAY MODES Z 0 (1865) DECAY MODES Z 0 (1865) DECAY MODES NODE=B096215;NODE=B096 Mode

249

Study of Bbar to Xu l nubar Decays in BBbar Events Tagged by a Fully Reconstructed B-meson Decay and Determination of |V_{ub}|  

SciTech Connect

We report measurements of partial branching fractions for inclusive charmless semileptonic B decays {bar B} {yields} X{sub u}{ell}{bar {nu}}, and the determination of the CKM matrix element |V{sub ub}|. The analysis is based on a sample of 467 million {Upsilon}(4S) {yields} B{bar B} decays recorded with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. We select events in which the decay of one of the B mesons is fully reconstructed and an electron or a muon signals the semileptonic decay of the other B meson. We measure partial branching fractions {Delta}{Beta} in several restricted regions of phase space and determine the CKM element |V{sub ub}| based on four different QCD predictions. For decays with a charged lepton momentum p*{sub {ell}} > 1.0 GeV in the B meson rest frame, we obtain {Delta}{Beta} = (1.80 {+-} 0.13{sub stat.} {+-} 0.15{sub sys.} {+-} 0.02{sub theo.}) x 10{sup -3} from a maximum likelihood fit to the two-dimensional M{sub X} - q{sup 2} distribution. Here, M{sub X} refers to the invariant mass of the final state hadron X and q{sup 2} is the invariant mass squared of the charged lepton and neutrino. From this measurement we extract |V{sub ub}| = (4.31 {+-} 0.25{sub exp.} {+-} 0.16{sub theo.}) x 10{sup -3} as the arithmetic average of four results obtained from four different QCD predictions of the partial rate. We separately determine partial branching fractions for {bar B}{sup 0} and B{sup -} decays and derive a limit on the isospin breaking in {bar B} {yields} X{sub u}{ell}{bar {nu}} decays.

Lees, J.P.

2012-07-13T23:59:59.000Z

250

Transformation Optics in Nonvacuum Initial Dielectric Media  

E-Print Network (OSTI)

Previous formulations of transformation optics have generally been restricted to transformations from relatively simple initial media, such as the vacuum, because of limitations due to their non-covariance. I show that a completely covariant approach enables arbitrary transformations from arbitrarily complex initial linear dielectrics.

Thompson, Robert T

2010-01-01T23:59:59.000Z

251

Predictive discrete latent factor models for large scale dyadic data  

Science Conference Proceedings (OSTI)

We propose a novel statistical method to predict large scale dyadic response variables in the presence of covariate information. Our approach simultaneously incorporates the effect of covariates and estimates local structure that is induced by interactions ... Keywords: co-clustering, dyadic data, generalized linear regression, latent factor modeling

Deepak Agarwal; Srujana Merugu

2007-08-01T23:59:59.000Z

252

Evaluation of an ecosystem model for a wheat-maize double cropping system over the North China Plain  

Science Conference Proceedings (OSTI)

A process-based ecosystem model (Vegetation-atmosphere Interface Processes (VIP) model) is expanded, and then validated against three years' biometric, soil moisture and eddy-covariance fluxes data over a winter wheat-summer maize cropping system in ... Keywords: Eddy covariance, Evapotranspiration, Net ecosystem production, Uncertainty, VIP model

Xingguo Mo; Suxia Liu; Zhonghui Lin

2012-06-01T23:59:59.000Z

253

Improved principal component monitoring using the local approach  

Science Conference Proceedings (OSTI)

This paper shows that current multivariate statistical monitoring technology may not detect incipient changes in the variable covariance structure nor changes in the geometry of the underlying variable decomposition. To overcome these deficiencies, the ... Keywords: Covariance structure, Dynamics, Fault detection and isolation, Local approach, Principal component analysis

Uwe Kruger; Sukhbinder Kumar; Tim Littler

2007-09-01T23:59:59.000Z

254

SIC~POVMs and Clifford groups in prime dimensions  

E-Print Network (OSTI)

We show that in prime dimensions not equal to three, each group covariant symmetric informationally complete positive operator valued measure (SIC~POVM) is covariant with respect to a unique Heisenberg--Weyl (HW) group. Moreover, the symmetry group of the SIC~POVM is a subgroup of the Clifford group. Hence, two SIC~POVMs covariant with respect to the HW group are unitarily or antiunitarily equivalent if and only if they are on the same orbit of the extended Clifford group. In dimension three, each group covariant SIC~POVM may be covariant with respect to three or nine HW groups, and the symmetry group of the SIC~POVM is a subgroup of at least one of the Clifford groups of these HW groups respectively. There may exist two or three orbits of equivalent SIC~POVMs for each group covariant SIC~POVM, depending on the order of its symmetry group. We then establish a complete equivalence relation among group covariant SIC~POVMs in dimension three, and classify inequivalent ones according to the geometric phases associated with fiducial vectors. Finally, we uncover additional SIC~POVMs by regrouping of the fiducial vectors from different SIC~POVMs which may or may not be on the same orbit of the extended Clifford group.

Huangjun Zhu

2010-03-18T23:59:59.000Z

255

SIC-POVMs and Clifford groups in prime dimensions  

E-Print Network (OSTI)

We show that in prime dimensions not equal to 3, each group covariant symmetric informationally complete positive operator valued measure (SIC-POVM) is covariant with respect to a unique Heisenberg-Weyl (HW) group. Moreover, the symmetry group of the SIC-POVM is a subgroup of the Clifford group. And two SIC-POVMs covariant with respect to the HW group are unitary or antiunitary equivalent if and only if they are on the same orbit of the extended Clifford group. In dimension 3, each group covariant SIC-POVM may be covariant with respect to 3 or 9 HW groups, and the symmetry group of the SIC-POVM is a subgroup of at least one of the Clifford groups of these HW groups respectively. There may exist 2 or 3 equivalent orbits for each group covariant SIC-POVM. We also establish a complete equivalence relationship of group covariant SIC-POVMs in dimension 3, and classify all inequivalent ones according to the geometric phases associated with fiducial vectors.

Zhu, Huangjun

2010-01-01T23:59:59.000Z

256

Two-Sample Kalman Filter for Steady-State Data Assimilation  

Science Conference Proceedings (OSTI)

In this paper, a new iterative algorithm for computing a steady-state Kalman gain is proposed. This algorithm utilizes two model forecasts with statistically independent random perturbations to determine the error covariance used to define a ...

Julius H. Sumihar; Martin Verlaan; Arnold W. Heemink

2008-11-01T23:59:59.000Z

257

Application of the Multigrid Data Assimilation Scheme to the China Seas’ Temperature Forecast  

Science Conference Proceedings (OSTI)

Correlation scales have been used in the traditional scheme of three-dimensional variational data assimilation (3DVAR) to estimate the background (or first guess) error covariance matrix (the matrix in brief) for the numerical forecast and ...

Wei Li; Yuanfu Xie; Zhongjie He; Guijun Han; Kexiu Liu; Jirui Ma; Dong Li

2008-11-01T23:59:59.000Z

258

Snow Temperature Changes within a Seasonal Snowpack and their Relationship to Turbulent Fluxes of Sensible and Latent Heat  

Science Conference Proceedings (OSTI)

Snowpack temperatures from a subalpine forest below Niwot Ridge, Colorado are examined with respect to atmospheric conditions and the 30-min above-canopy and subcanopy eddy covariance fluxes of sensible Qh and latent Qe heat. In the lower snowpack,...

Sean P. Burns; Noah P. Molotch; Mark W. Williams; John F. Knowles; Brian Seok; Russell K. Monson; Andrew A. Turnipseed; Peter D. Blanken

259

Method and system to estimate variables in an integrated gasification combined cycle (IGCC) plant  

DOE Patents (OSTI)

System and method to estimate variables in an integrated gasification combined cycle (IGCC) plant are provided. The system includes a sensor suite to measure respective plant input and output variables. An extended Kalman filter (EKF) receives sensed plant input variables and includes a dynamic model to generate a plurality of plant state estimates and a covariance matrix for the state estimates. A preemptive-constraining processor is configured to preemptively constrain the state estimates and covariance matrix to be free of constraint violations. A measurement-correction processor may be configured to correct constrained state estimates and a constrained covariance matrix based on processing of sensed plant output variables. The measurement-correction processor is coupled to update the dynamic model with corrected state estimates and a corrected covariance matrix. The updated dynamic model may be configured to estimate values for at least one plant variable not originally sensed by the sensor suite.

Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

2013-09-17T23:59:59.000Z

260

An Empirical Benchmark for Decadal Forecasts of Global Surface Temperature Anomalies  

Science Conference Proceedings (OSTI)

The suitability of a linear inverse model (LIM) as a benchmark for decadal surface temperature forecast skill is demonstrated. Constructed from the observed simultaneous and 1-yr lag covariability statistics of annually averaged sea surface ...

Matthew Newman

2013-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Interannual Seesaw between the Aleutian and Icelandic Lows. Part II: Its Significance in the Interannual Variability over the Wintertime Northern Hemisphere  

Science Conference Proceedings (OSTI)

Through analysis of observational data for the period of 1973–94, the late-winter formation of an interannual seesaw between the surface Aleutian and Icelandic lows (AL and IL, respectively) is shown to significantly impact the covariance ...

Meiji Honda; Hisashi Nakamura

2001-12-01T23:59:59.000Z

262

Observed atmospheric response to cold season sea ice variability in the Arctic  

Science Conference Proceedings (OSTI)

The relation between weekly Arctic sea ice concentrations (SIC) from December to April and sea level pressure (SLP) during 1979-2007 is investigated using Maximum Covariance Analysis (MCA). In the North Atlantic sector, the interaction between the ...

Claude Frankignoul; Nathalie Sennéchael; Pierre Cauchy

263

Regional Characteristics of the Northern Hemisphere Wintertime Circulation: A Comparison of the Simulation of a GFDL General Circulation Model with Observations  

Science Conference Proceedings (OSTI)

The hemispheric distributions of a selected set of temporal mean, variance and covariance statistics produced by a general circulation model developed at the Geophysical Fluid Dynamics Laboratory are compared with observations. The fields ...

Maurice L. Blackmon; Ngar-Cheung Lau

1980-03-01T23:59:59.000Z

264

Reanalysis without Radiosondes Using Ensemble Data Assimilation  

Science Conference Proceedings (OSTI)

Studies using idealized ensemble data assimilation systems have shown that flow-dependent background-error covariances are most beneficial when the observing network is sparse. The computational cost of recently proposed ensemble data ...

Jeffrey S. Whitaker; Gilbert P. Compo; Xue Wei; Thomas M. Hamill

2004-05-01T23:59:59.000Z

265

Effects of Serial Dependence and Large-Scale Tropospheric Circulation on Midlatitude North American Terrestrial Carbon Dioxide Exchange  

Science Conference Proceedings (OSTI)

Linear regression was used to relate modes of tropospheric circulation variability to estimates of gross ecosystem production (GEP) and ecosystem respiration (ER) measured at 14 midlatitude North American eddy covariance (EC) towers. The North ...

Robbie A. Hember; Peter M. Lafleur

2008-02-01T23:59:59.000Z

266

Seasonal and Interannual Variations of Evapotranspiration and Energy Exchange over Different Land Surfaces in a Semiarid Area of China  

Science Conference Proceedings (OSTI)

Seasonal and interannual variations of evapotranspiration (ET) and energy exchange were estimated over degraded grassland and cropland land surfaces in a semiarid region of northeastern China using the eddy covariance technique from 2003 to 2008. ...

Liu Huizhi; Feng Jianwu

2012-10-01T23:59:59.000Z

267

Theory and Applications of the Minimum Spanning Tree Rank Histogram  

Science Conference Proceedings (OSTI)

A minimum spanning tree (MST) rank histogram (RH) is a multidimensional ensemble reliability verification tool. The construction of debiased, decorrelated, and covariance-homogenized MST RHs is described. Experiments using Euclidean L2, variance, ...

Daniel Gombos; James A. Hansen; Jun Du; Jeff McQueen

2007-04-01T23:59:59.000Z

268

Dominant Balances and Exchanges of the Atmospheric Water Cycle in the Reanalysis 2 at Diurnal, Annual, and Intraseasonal Time Scales  

Science Conference Proceedings (OSTI)

Output from the National Centers for Environmental Prediction–Department of Energy (NCEP–DOE) Reanalysis 2 (R2) is passed through a broadband filter to determine the normalized covariances that describe the variance of the atmospheric water cycle ...

Alex C. Ruane; John O. Roads

2008-08-01T23:59:59.000Z

269

A Relationship between Energy and Angular Momentum Conservation in Dynamical Models  

Science Conference Proceedings (OSTI)

In Newtonian particle dynamics the covariance of the kinetic energy equation to transformation between different inertial frames may he demonstrated only if the correct momentum equation is applied. A similar relation exists between the angular ...

A. A. White

1989-06-01T23:59:59.000Z

270

Warming Break Trends and Fractional Integration in the Northern, Southern, and Global Temperature Anomaly Series  

Science Conference Proceedings (OSTI)

This paper deals with the estimation of time trends in temperature anomaly series. However, instead of imposing that the estimated residuals from the time trends are covariance stationary processes with spectral density that is positive and ...

Luis A. Gil-Alana

2008-04-01T23:59:59.000Z

271

Regression-Based Methods for Finding Coupled Patterns  

Science Conference Proceedings (OSTI)

There are a variety of multivariate statistical methods for analyzing the relations between two datasets. Two commonly used methods are canonical correlation analysis (CCA) and maximum covariance analysis (MCA), which find the projections of the ...

Michael K. Tippett; Timothy DelSole; Simon J. Mason; Anthony G. Barnston

2008-09-01T23:59:59.000Z

272

The Impact of Ocean Data Assimilation on Seasonal-to-Interannual Forecasts: A Case Study of the 2006 El Niño Event  

Science Conference Proceedings (OSTI)

This study investigates the impact of four different ocean analyses on coupled forecasts of the 2006 El Niño event. Forecasts initialized in June 2006 using ocean analyses from an assimilation that uses flow-dependent background error covariances ...

Shu-Chih Yang; Michele Rienecker; Christian Keppenne

2010-08-01T23:59:59.000Z

273

Analysis and Interpretation of Dual-Polarized Radar Measurements at +45° and ?45° Linear Polarization States  

Science Conference Proceedings (OSTI)

Equations are derived for transforming radar data obtained with ±45° linear polarization states to conventional radar parameters measured at horizontal and vertical polarization states. The derivation is based on the covariance matrix and assumes ...

V. Chandrasekar; J. Hubbert; V. N. Bringi; P. F. Meischner

1994-04-01T23:59:59.000Z

274

Star Products for Relativistic Quantum Mechanics  

E-Print Network (OSTI)

The star product formalism has proved to be an alternative formulation for nonrelativistic quantum mechanics. We want introduce here a covariant star product in order to extend the star product formalism to relativistic quantum mechanics in the proper time formulation.

P. Henselder

2007-05-24T23:59:59.000Z

275

A Note on Energy-Momentum Conservation in Palatini Formulation of L(R) Gravity  

E-Print Network (OSTI)

By establishing that Palatini formulation of $L(R)$ gravity is equivalent to $\\omega=-3/2$ Brans-Dicke theory, we show that energy-momentum tensor is covariantly conserved in this type of modified gravity theory.

Peng Wang; Gilberto M. Kremer; Daniele S. M. Alves; Xin-He Meng

2004-08-18T23:59:59.000Z

276

--No Title--  

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

a successful non-linear covariant ghost-free generalization of Fierz-Pauli massive gravity theory, the dRGT theory. I will explore the cosmology in the decoupling limit of this...

277

Structure formation in modified gravity  

Science Conference Proceedings (OSTI)

We pursue a (1+3) ?covariant analysis of cosmological peculiar velocity of pressure?free matter induced by the matter density perturbations in modified f(R) gravity theories. Instead of working in a quasi?Newtonian Eulerian frame

D. M. Solomons; P. K. S. Dunsby; S. Carloni

2009-01-01T23:59:59.000Z

278

Structure of the Reynolds Stress in a Canopy Layer  

Science Conference Proceedings (OSTI)

The u, w velocity covariance above and within a plant canopy (Zea mays L) was examined using the technique of quadrant analysis to separate the momentum transport into events classified as sweep, ejection, and outward and inward interactions. A ...

Roger H. Shaw; Jahangir Tavangar; David P. Ward

1983-11-01T23:59:59.000Z

279

Antarctic Sea Ice Climatology, Variability, and Late Twentieth-Century Change in CCSM4  

Science Conference Proceedings (OSTI)

A preindustrial control run and an ensemble of twentieth-century integrations of the Community Climate System Model, version 4 (CCSM4), are evaluated for Antarctic sea ice climatology, modes of variability, trends, and covariance with related ...

Laura Landrum; Marika M. Holland; David P. Schneider; Elizabeth Hunke

2012-07-01T23:59:59.000Z

280

An Examination of the Incremental Balance in a Global Ensemble-Based 3D-Var Data Assimilation System  

Science Conference Proceedings (OSTI)

This study examines the modification to the balance properties of the analysis increments in a global three-dimensional variational data assimilation scheme when using flow-dependent background-error covariances derived from an operational ...

Jean-François Caron; Luc Fillion

2010-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

A Consistent Hybrid Variational-Smoothing Data Assimilation Method: Application to a Simple Shallow-Water Model of the Turbulent Midlatitude Ocean  

Science Conference Proceedings (OSTI)

In the standard four-dimensional variational data assimilation (4D-Var) algorithm the background error covariance matrix remains static over time. It may therefore be unable to correctly take into account the information accumulated by a system ...

Monika Krysta; Eric Blayo; Emmanuel Cosme; Jacques Verron

2011-11-01T23:59:59.000Z

282

Parallel Implementation of a Kalman Filter for Constituent Data Assimilation  

Science Conference Proceedings (OSTI)

A Kalman filter for the assimilation of long-lived atmospheric chemical constituents was developed for two-dimensional transport models on isentropic surfaces over the globe. Since the Kalman filter calculates the error covariances of the ...

P. M. Lyster; S. E. Cohn; R. Ménard; L-P. Chang; S-J. Lin; R. G. Olsen

1997-07-01T23:59:59.000Z

283

Generalized Inversion of Tropical Atmosphere–Ocean Data and a Coupled Model of the Tropical Pacific  

Science Conference Proceedings (OSTI)

It is hypothesized that the circulation of the tropical Pacific Ocean and atmosphere satisfies the equations of a simple coupled model to within errors having specified covariances, and that the Tropical Atmosphere–Ocean array (TAO) measures the ...

Andrew F. Bennett; Boon S. Chua; D. Ed Harrison; Michael J. McPhaden

1998-07-01T23:59:59.000Z

284

Characteristics of Land–Atmosphere Interaction Parameters over the Tibetan Plateau  

Science Conference Proceedings (OSTI)

In this study, eddy covariance flux data collected from three research stations on the Tibetan Plateau—Qomolangma for Atmospheric and Environmental Observation and Research, Nam Co for Multisphere Observation and Research, and Southeast Tibet ...

Shuzhou Wang; Yaoming Ma

2011-08-01T23:59:59.000Z

285

Assimilation of Stratospheric Chemical Tracer Observations Using a Kalman Filter. Part II: ?2-Validated Results and Analysis of Variance and Correlation Dynamics  

Science Conference Proceedings (OSTI)

A Kalman filter system designed for the assimilation of limb-sounding observations of stratospheric chemical tracers, which has four tunable covariance parameters, was developed in Part I of this two-part paper. The assimilation results of CH4 ...

Richard Ménard; Lang-Ping Chang

2000-08-01T23:59:59.000Z

286

Higher order asymptotic inference in remote sensing of oceanic and planetary environments  

E-Print Network (OSTI)

An inference method based on higher order asymptotic expansions of the bias and covariance of the Maximum Likelihood Estimate (MLE) is used to investigate the accuracy of parameter estimates obtained from remote sensing ...

Bertsatos, loannis

2010-01-01T23:59:59.000Z

287

Assessment of a modified version of the EM algorithm for remote sensing data classification  

Science Conference Proceedings (OSTI)

This work aims to present an assessment of a modified version of the standard EM clustering algorithm for remote sensing data classification. As observing clusters with very similar mean vectors but differing only on the covariance structure is not natural ...

Thales Sehn Korting; Luciano Vieira Dutra; Guaraci José Erthal; Leila Maria Garcia Fonseca

2010-11-01T23:59:59.000Z

288

Evolution Dynamics of Tropical Ocean-Atmosphere Annual Cycle Variability  

Science Conference Proceedings (OSTI)

The structure of ocean-atmosphere annual cycle variability is extracted from the revised Comprehensive Ocean-Atmosphere Data Set SSTs, surface winds, and the latent heat (LH) and net shortwave (SW) surface fluxes using the covariance-based ...

Sumant Nigam; Yi Chao

1996-12-01T23:59:59.000Z

289

Receiver and Analog Homodyning Effects on Incoherent Doppler Velocity Estimates  

Science Conference Proceedings (OSTI)

Oceanic incoherent Doppler sonar systems (current profiling systems) employing intrapulse covariance calculations and related first spectral-moment approximations to calculate volumetric fluid motion are sensitive to design tolerance of the sonar ...

D. Scott Hansen

1985-12-01T23:59:59.000Z

290

Forecasting Pacific SSTs: Linear Inverse Model Predictions of the PDO  

Science Conference Proceedings (OSTI)

A linear inverse model (LIM) is used to predict Pacific (30°S–60°N) sea surface temperature anomalies (SSTAs), including the Pacific decadal oscillation (PDO). The LIM is derived from the observed simultaneous and lagged covariance statistics of ...

Michael A. Alexander; Ludmila Matrosova; Cécile Penland; James D. Scott; Ping Chang

2008-01-01T23:59:59.000Z

291

Evaluation of the Ensemble Transform Analysis Perturbation Scheme at NRL  

Science Conference Proceedings (OSTI)

The ensemble transform (ET) scheme changes forecast perturbations into analysis perturbations whose amplitudes and directions are consistent with a user-provided estimate of analysis error covariance. A practical demonstration of the ET scheme ...

Justin G. McLay; Craig H. Bishop; Carolyn A. Reynolds

2008-03-01T23:59:59.000Z

292

Ensemble Square Root Filters  

Science Conference Proceedings (OSTI)

Ensemble data assimilation methods assimilate observations using state-space estimation methods and low-rank representations of forecast and analysis error covariances. A key element of such methods is the transformation of the forecast ensemble ...

Michael K. Tippett; Jeffrey L. Anderson; Craig H. Bishop; Thomas M. Hamill; Jeffrey S. Whitaker

2003-07-01T23:59:59.000Z

293

Optimization of the Fixed Global Observing Network in a Simple Model  

Science Conference Proceedings (OSTI)

An exact closed form expression for the infinite time analysis and forecast error covariances of a Kalman filter is used to investigate how the locations of fixed observing platforms such as radiosonde stations affect global distributions of ...

Craig H. Bishop; Carolyn A. Reynolds; Michael K. Tippett

2003-06-01T23:59:59.000Z

294

The Direct Estimation of Near-Bottom Turbulent Fluxes in the Presence of Energetic Wave Motions  

Science Conference Proceedings (OSTI)

Velocities produced by energetic waves can contaminate direct covariance estimates of near-bottom turbulent shear stress and turbulent heat flux. A new adaptive filtering technique is introduced to minimize the contribution of wave-induced ...

W. J. Shaw; J. H. Trowbridge

2001-09-01T23:59:59.000Z

295

Essays on annuitization and housing choice  

E-Print Network (OSTI)

Chapter 1 For most US households, labor income is the most important source of wealth and housing is the most important risky asset. A natural intuition is thus that households whose incomes covary relatively strongly with ...

Davidoff, Thomas, 1971-

2002-01-01T23:59:59.000Z

296

Observed and Simulated Upper-Tropospheric Water Vapor Feedback  

Science Conference Proceedings (OSTI)

Satellite measurements from the Atmospheric Infrared Sounder (AIRS) in the upper troposphere over 4.5 yr are used to assess the covariation of upper-tropospheric humidity and temperature with surface temperatures, which can be used to constrain ...

A. Gettelman; Q. Fu

2008-07-01T23:59:59.000Z

297

A Consensus Model for Seasonal Hurricane Prediction  

Science Conference Proceedings (OSTI)

The authors apply a procedure called Bayesian model averaging (BMA) for examining the utility of a set of covariates for predicting the distribution of U.S. hurricane counts and demonstrating a consensus model for seasonal prediction. Hurricane ...

Thomas H. Jagger; James B. Elsner

2010-11-01T23:59:59.000Z

298

Observed Southern Hemisphere Eddy Statistics at 500 mb: Frequency and Spatial Dependence  

Science Conference Proceedings (OSTI)

Nearly eight years of daily Southern Hemisphere analyses at 500 mb have been used to define the spatial dependence of the variance fields of geopotential height and the two geostrophic wind components, the corresponding covariance fields, and the ...

Kevin E. Trenberth

1981-12-01T23:59:59.000Z

299

The Life Cycle of the Madden–Julian Oscillation  

Science Conference Proceedings (OSTI)

A composite life cycle of the Madden–Julian oscillation (MJO) is constructed from the cross covariance between outgoing longwave radiation (OLR), wind, and temperature. To focus on the role of convection, the composite is based on episodes when a ...

Harry H. Hendon; Murry L. Salby

1994-08-01T23:59:59.000Z

300

Effects of Recent Environmental Changes on Global Seismicity and Volcanism  

Science Conference Proceedings (OSTI)

A covariation of recent global environmental changes and seismicity on Earth is demonstrated. Presently, rising concern about anthropogenic activities and their consequences on the cryosphere and environment have always overlooked changes related ...

Evgeny A. Podolskiy

2009-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Bayesian Design and Analysis for Superensemble-Based Climate Forecasting  

Science Conference Proceedings (OSTI)

The authors develop statistical data models to combine ensembles from multiple climate models in a fashion that accounts for uncertainty. This formulation enables treatment of model specific means, biases, and covariance matrices of the ...

L. Mark Berliner; Yongku Kim

2008-05-01T23:59:59.000Z

302

Mixed-Resolution Ensemble Data Assimilation  

Science Conference Proceedings (OSTI)

Ensemble Kalman filters perform data assimilation by forming a background covariance matrix from an ensemble forecast. Most of the literature on ensemble Kalman filters assumes that all ensemble members come from the same model. This article ...

Sabrina Rainwater; Brian Hunt

2013-09-01T23:59:59.000Z

303

15 Puzzle 2x mod 1 Map A Integral A Sequence abc Conjecture ...  

E-Print Network (OSTI)

... Covariant Tensors Cover Cover (Minimal) Cow Hitch Cox's Theorem Coxeter .... Early Results Electric Motor Curve Elementary Proof Elevator Paradox Elkies ..... Kirby's List Kirillov-Bernat Theorem Kirillov Conjecture Kirkman's Schoolgirl ..... Untouchable Numbers Urchin Utility Graph Problem Utility Problem Valency ...

304

The Schaake Shuffle: A Method for Reconstructing Space–Time Variability in Forecasted Precipitation and Temperature Fields  

Science Conference Proceedings (OSTI)

A number of statistical methods that are used to provide local-scale ensemble forecasts of precipitation and temperature do not contain realistic spatial covariability between neighboring stations or realistic temporal persistence for subsequent ...

Martyn Clark; Subhrendu Gangopadhyay; Lauren Hay; Balaji Rajagopalan; Robert Wilby

2004-02-01T23:59:59.000Z

305

A comparison of the carbon dioxide fluxes of two annual cropping systems and a perennial hay field in southern Manitoba over 30 months.  

E-Print Network (OSTI)

??The eddy-covariance method was used to measure net ecosystem productivity over three adjacent fields from 2009 to 2011: two annual cropping systems (oat-canola-oat and hay-oat-fallow)… (more)

Taylor, Amanda M.

2013-01-01T23:59:59.000Z

306

Black Carbon and West African Monsoon precipitation:observations and simulations  

E-Print Network (OSTI)

We have recently investigated large-scale co-variability between aerosol and precipitation and other meteorological variables in the West African Monsoon (WAM) region using long term satellite observations and reanalysis ...

Huang, J.

307

Prediction of the Probable Errors of Predictions  

Science Conference Proceedings (OSTI)

We propose here a method of “stochastic-dynamic” prediction that is computationally more efficient than integration of the full set of “second-moment” equations. This gain is achieved by omitting covariances between modes in different interacting ...

Philip D. Thompson

1985-02-01T23:59:59.000Z

308

On Estimating Wet Canopy Evaporation from Deciduous and Coniferous Forests in the Asian Monsoon Climate  

Science Conference Proceedings (OSTI)

Continuous and direct measurement of evapotranspiration (ET) by the eddy covariance (EC) technique is still a challenge under monsoon climate because of a considerable amount of missing data during the long rainy periods and the consequential gap-...

Minseok Kang; Hyojung Kwon; Jung Hwa Cheon; Joon Kim

2012-06-01T23:59:59.000Z

309

Analysis of Tidal Straining as Driver for Estuarine Circulation in Well-Mixed Estuaries  

Science Conference Proceedings (OSTI)

Tidal straining, which can mathematically be described as the covariance between eddy viscosity and vertical shear of the along-channel velocity component, has been acknowledged as one of the major drivers for estuarine circulation in channelized ...

Hans Burchard; Henk M. Schuttelaars

2012-02-01T23:59:59.000Z

310

Accelerating the EnKF Spinup for Typhoon Assimilation and Prediction  

Science Conference Proceedings (OSTI)

A mesoscale ensemble Kalman filter (EnKF) for a regional model is often initialized from global analysis products and with initial ensemble perturbations constructed based on the background error covariance used in the three-dimensional ...

Shu-Chih Yang; Eugenia Kalnay; Takemasa Miyoshi

2012-08-01T23:59:59.000Z

311

Remote and Local Forcing in the Brazil–Malvinas Region  

Science Conference Proceedings (OSTI)

Origins of the seasonal variability observed in current meter data from the Malvinas (Falkland) Current are sought in the wind field on both a regional and circumpolar scale. A singular value decomposition of the covariance of the fields makes it ...

Frédéric Vivier; Christine Provost; Michael P. Meredith

2001-04-01T23:59:59.000Z

312

Analysis of Surface Wind and Its Gradient In a Mesoscale Wind Observation Network  

Science Conference Proceedings (OSTI)

The surface wind is analysed with an optimum interpolation method. Covariances and long-term averages of wind observations are parameterized from data in the fairly dense synoptic wind observation network in the Netherlands.

G. J. Cats

1980-08-01T23:59:59.000Z

313

A Study of Wind Stress Determination Methods from a Ship and an Offshore Tower  

Science Conference Proceedings (OSTI)

Comparisons are made between surface wind stress measurements obtained by the inertial-dissipation and direct covariance methods on a stable offshore tower and by the inertial-dissipation and bulk methods on a ship. The shipboard inertial-...

Paul A. Frederickson; Kenneth L. Davidson; James B. Edson

1997-08-01T23:59:59.000Z

314

A Surrogate Ensemble Study of Sea Level Reconstructions  

Science Conference Proceedings (OSTI)

This study investigates the possibility of reconstructing past global mean sea levels. Reconstruction methods rely on historical measurements from tide gauges combined with knowledge about the spatial covariance structure of the sea level field ...

Bo Christiansen; T. Schmith; P. Thejll

2010-08-01T23:59:59.000Z

315

Management and Conservation Territory Occupancy by Common Loons in  

E-Print Network (OSTI)

Creek Timber Company, Glacier National Park, Blackfeet Indian Reservation, and private landowners.g., observations complet- ed in rain, snow, wind, etc.) were verified by a second observer. Covariate Data

Montana, University of

316

2009 The Authors Journal Compilation 2009 Blackwell Publishing Ltd  

E-Print Network (OSTI)

Creek Timber Company, Glacier National Park, Blackfeet Indian Reservation, and private landowners.g., observations complet- ed in rain, snow, wind, etc.) were verified by a second observer. Covariate Data

Resler, Lynn M.

317

Reconciling Non-Gaussian Climate Statistics with Linear Dynamics  

Science Conference Proceedings (OSTI)

Linear stochastically forced models have been found to be competitive with comprehensive nonlinear weather and climate models at representing many features of the observed covariance statistics and at predictions beyond a week. Their success ...

Prashant D. Sardeshmukh; Philip Sura

2009-03-01T23:59:59.000Z

318

Northern Hemisphere Winter Atmospheric Transient Eddy Heat Fluxes and the Gulf Stream and Kuroshio–Oyashio Extension Variability  

Science Conference Proceedings (OSTI)

Spatial and temporal covariability between the atmospheric transient eddy heat fluxes (i.e., ??T? and ??q?) in the Northern Hemisphere winter (January–March) and the paths of the Gulf Stream (GS), Kuroshio Extension (KE), and Oyashio Extension ...

Young-Oh Kwon; Terrence M. Joyce

2013-12-01T23:59:59.000Z

319

The Interpretation and Estimation of Effective Sample Size  

Science Conference Proceedings (OSTI)

Statistical and dynamical relationships between observed values of a geophysical system or model effectively reduce the number of independent data. This reduction is expressible in terms of the covariance structure of the process and, in some ...

H. J. Thiébaux; F. W. Zwiers

1984-05-01T23:59:59.000Z

320

Simulation of Three-Dimensional Turbulent Velocity Fields  

Science Conference Proceedings (OSTI)

New algorithms for the simulation of three-dimensional homogeneous turbulent velocity fields are compared with standard spectral domain algorithms. Results are presented for a von Kármán model of the covariance tensor. For typical atmospheric ...

Rod Frehlich; Larry Cornman; Robert Sharman

2001-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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.


321

A Bayesian Algorithm for Reconstructing Climate Anomalies in Space and Time. Part II: Comparison with the Regularized Expectation–Maximization Algorithm  

Science Conference Proceedings (OSTI)

Part I presented a Bayesian algorithm for reconstructing climate anomalies in space and time (BARCAST). This method involves specifying simple parametric forms for the spatial covariance and temporal evolution of the climate field as well as “...

Martin P. Tingley; Peter Huybers

2010-05-01T23:59:59.000Z

322

Examining Mechanisms of Variability within the Pacific Storm Track: Upstream Seeding and Jet-Core Strength  

Science Conference Proceedings (OSTI)

This paper examines how variations in two mechanisms, upstream seeding and jet-core strength, relate to storminess within the cold season (October–April) Pacific storm track. It is found that about 17% of observed storminess covaries with the ...

Sandra M. Penny; David S. Battisti; Gerard H. Roe

2013-07-01T23:59:59.000Z

323

Behavioral Modeling of Nonlinearities and Memory Effects in Power Amplifiers  

E-Print Network (OSTI)

This plot is using a 54 usec training sequence, and the bestThis plot is using a 54 usec training sequence, and the bestCDMA Auto-Covariance Time (usec) Figure 2.15 Autocorrelation

Draxler, Paul J.

324

Can Quasigeostrophic Turbulence Be Modeled Stochastically?  

Science Conference Proceedings (OSTI)

Numerically generated data of quasigeostrophic turbulence in an equilibrated shear flow are analyzed to determine the extent to which they can be modeled by a Markov model. The time lagged covariances are collected into a matrix, C?, and are ...

Timothy DelSole

1996-06-01T23:59:59.000Z

325

An Ensemble-Based Four-Dimensional Variational Data Assimilation Scheme. Part I: Technical Formulation and Preliminary Test  

Science Conference Proceedings (OSTI)

Applying a flow-dependent background error covariance ( matrix) in variational data assimilation has been a topic of interest among researchers in recent years. In this paper, an ensemble-based four-dimensional variational (En4DVAR) algorithm, ...

Chengsi Liu; Qingnong Xiao; Bin Wang

2008-09-01T23:59:59.000Z

326

Effects of Land Use and Meteorological Conditions on Local and Regional Momentum Transport and Roughness for Midwestern Cropping Systems  

Science Conference Proceedings (OSTI)

Eddy covariance measurements of wind speed u and shear velocity u* from tower- and aircraft-based systems collected over rapidly developing corn- (Zea mays L.) and soybean [Glycine max (L.) Merr.] fields were used in determining the local and ...

William P. Kustas; John H. Prueger; J. Ian MacPherson; Mengistu Wolde; Fuqin Li

2005-12-01T23:59:59.000Z

327

Impact of Using Different Time-Averaged Inputs for Estimating Sensible Heat Flux of Riparian Vegetation Using Radiometric Surface Temperature  

Science Conference Proceedings (OSTI)

A riparian corridor along the Rio Grande dominated by the Eurasian tamarisk or salt cedar (Tamarix spp.) is being studied to determine water and energy exchange rates using eddy covariance instrumentation mounted on a 12-m tower. The potential of ...

William P. Kustas; John H. Prueger; Lawrence E. Hipps

2002-03-01T23:59:59.000Z

328

Suboptimal Schemes for Atmospheric Data Assimilation Based on the Kalman Filter  

Science Conference Proceedings (OSTI)

This work is directed toward approximating the evolution of forecast error covariances for data assimilation. The performance of different algorithms based on simplification of the standard Kalman filter (KF) is studied. These are suboptimal ...

Ricardo Todling; Stephen E. Cohn

1994-11-01T23:59:59.000Z

329

A copula-based heuristic for scenario generation  

E-Print Network (OSTI)

Aug 27, 2013 ... The original publication is available at www.springerlink.com. ... always speci ed using the correlation (or variance-covariance) matrix. ... to exist in nancial data (

330

Importance of Low-Frequency Contributions to Eddy Fluxes Observed over Rough Surfaces  

Science Conference Proceedings (OSTI)

Eddy covariance flux observations at a deciduous temperate forest site (83 days) and at a boreal forest site (21 days) are analyzed for midday periods (1100–1400 LT). Approximate stationarity of the time series is demonstrated, and the ensemble-...

Ricardo K. Sakai; David R. Fitzjarrald; Kathleen E. Moore

2001-12-01T23:59:59.000Z

331

Diagnosing Heat and Vorticity Budgets of Annual Coupled Rossby Waves  

Science Conference Proceedings (OSTI)

Annual coupled Rossby waves are generated at the west coast of Australia and propagate westward across the eastern Indian Ocean from 10° to 30°S in covarying sea level height (SLH), sea surface temperature (SST), and meridional surface wind (MSW) ...

Warren B. White; Jeffrey L. Annis

2005-07-01T23:59:59.000Z

332

Climate Field Reconstruction under Stationary and Nonstationary Forcing  

Science Conference Proceedings (OSTI)

The fidelity of climate reconstructions employing covariance-based calibration techniques is tested with varying levels of sparseness of available data during intervals of relatively constant (stationary) and increasing (nonstationary) forcing. ...

S. Rutherford; M. E. Mann; T. L. Delworth; R. J. Stouffer

2003-02-01T23:59:59.000Z

333

Improper Rotations'Symmetry of Electromagnetic Field and New Conserved Quantity of Complex Fields  

E-Print Network (OSTI)

It is established the partition of linear space $$ over the field of genuine scalars and pseudoscalars, the vectors in which are sets of contravariant and covariant electromagnetic field tensors and pseudotensors $F^{\\mu\

Yearchuck, D

2009-01-01T23:59:59.000Z

334

Northern Hemisphere Winter Atmospheric Transient Eddy Heat Fluxes and the Gulf Stream and Kuroshio-Oyashio Extension Variability  

Science Conference Proceedings (OSTI)

Spatial and temporal co-variability between the atmospheric transient eddy heat fluxes (i.e. and ) in the Northern Hemisphere winter (January-March) and the paths of the Gulf Stream (GS), Kuroshio Extension (KE), and Oyashio Extension ...

Young-Oh Kwon; Terrence M. Joyce

335

A Comparative Study of Observed Northern Hemisphere Circulation Statistics Based on GFDL and NMC Analyses. Part II: Transient Eddy Statistics and the Energy Cycle  

Science Conference Proceedings (OSTI)

The comparison between two sets of observed circulation statistics undertaken by Lau and Oort (1981) is continued in this study by examining the temporal variance and covariance statistics in these sets. The first (GFDL) set is compiled by ...

Ngar-Cheung Lau; Abraham H. Oort

1982-08-01T23:59:59.000Z

336

Impact Assessment of Simulated Doppler Wind Lidars with a Multivariate Variational Assimilation in the Tropics  

Science Conference Proceedings (OSTI)

This paper deals with the dynamical aspect of variational data assimilation in the tropics and the role of the background-error covariances in the observing system simulation experiments for the tropics. The study uses a model that describes the ...

Nedjeljka Žagar; Ad Stoffelen; Gert-Jan Marseille; Christophe Accadia; Peter Schlüssel

2008-07-01T23:59:59.000Z

337

Re-estimation of Nuclear Data and JEFF 3.1.1 Uncertainty Calculations  

SciTech Connect

This paper describes the method to define relevant targeted integral measurements that allow the improvement of nuclear data evaluations and the determination of corresponding reliable covariances. {sup 235}U and {sup 56}Fe examples are pointed out for the improvement of JEFF3 data. Utilizations of these covariances are shown for Sensitivity and Representativity studies, Uncertainty calculations, and Transposition of experimental results to industrial applications. S/U studies are more and more used in Reactor Physics and Safety-Criticality. However, the reliability of study results relies strongly on the ND covariance relevancy. Our method derives the real uncertainty associated with each evaluation from calibration on targeted integral measurements. These realistic covariance matrices allow reliable JEFF3.1.1 calculation of prior uncertainty due to nuclear data, as well as uncertainty reduction based on representative integral experiments, in challenging design calculations such as GEN3 and RJH reactors.

Santamarina, A. [Commissariat a l'Energie Atomique et aux Energies Alternatives; Bernard, D. [Commissariat a l'Energie Atomique et aux Energies Alternatives; Dos Santos, N. [Commissariat a l'Energie Atomique et aux Energies Alternatives; Leray, O. [Commissariat a l'Energie Atomique et aux Energies Alternatives; Vaglio, C. [Commissariat a l'Energie Atomique et aux Energies Alternatives; Leal, Luiz C [ORNL

2012-01-01T23:59:59.000Z

338

Spin-Gauge Theory of Gravity with Higgs-field Mechanism  

E-Print Network (OSTI)

We propose a Lorentz-covariant Yang-Mills spin-gauge theory, where the function valued Dirac matrices play the role of a non-scalar Higgs-field. As symmetry group we choose $SU(2) \\times U(1)$. After symmetry breaking a non-scalar Lorentz-covariant Higgs-field gravity appears, which can be interpreted within a classical limit as Einstein's metrical theory of gravity, where we restrict ourselves in a first step to its linearized version.

H. Dehnen; E. Hitzer

2013-06-10T23:59:59.000Z

339

Statistics for characterizing data on the periphery  

SciTech Connect

We introduce a class of statistics for characterizing the periphery of a distribution, and show that these statistics are particularly valuable for problems in target detection. Because so many detection algorithms are rooted in Gaussian statistics, we concentrate on ellipsoidal models of high-dimensional data distributions (that is to say: covariance matrices), but we recommend several alternatives to the sample covariance matrix that more efficiently model the periphery of a distribution, and can more effectively detect anomalous data samples.

Theiler, James P [Los Alamos National Laboratory; Hush, Donald R [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

340

in Topological Yang-Mills Theory  

E-Print Network (OSTI)

We introduce the covariant forms for the non-Abelian anomaly counterparts in topological Yang-Mills theory, which satisfies the topological descent equation modulo terms that vanish at the space of BRST fixed points. We use the covariant anomalies as a new set of observables, which can absorb both ? W and ? BRS ghost number violations of zeromodes. Then, we study some problems due to the zero-modes originated from the reducible connections.

unknown authors

1992-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Measurement of the B0(s) - anti-B0(s) Oscillation Frequency  

SciTech Connect

The authors present the first measurement of the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillation frequency {Delta}m{sub s}. They use 1 fb{sup -1} of data from p{bar p} collisions at {radical}s = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. The sample contains signals of 3600 fully reconstructed hadronic B{sub s} decays and 37,000 partially reconstructed semileptonic B{sub s} decays. They measure the probability as a function of proper decay time that the B{sub s} decays with the same, or opposite, flavor as the flavor at production and they find a signal consistent with B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations. The probability that random fluctuations could produce a comparable signal is 0.2%. Under the hypothesis that the signal is due to B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations, they measure {Delta}m{sub s} = 17.31{sub -0.18}{sup +0.33}(stat.) {+-} 0.07(syst.) ps{sup -1} and determine |V{sub td}/V{sub ts}| = 0.208{sub -0.002}{sup +0.001}(exp.){sub -0.006}{sup +0.008}(theo.).

Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; /Taiwan, Inst. Phys. /Argonne /Barcelona, IFAE /Baylor U. /INFN, Bologna /Bologna U. /Brandeis U. /UC, Davis /UCLA /UC, San Diego /UC, Santa Barbara

2006-06-01T23:59:59.000Z

342

Can Bounded Rationality Explain Excess Capacity? ?  

E-Print Network (OSTI)

Excess capacity is observed in many markets especially those where a substantial initial investment is required. The theoretical literature often explains this feature by strategic attempts to deter entry or to limit new entrants ’ market shares but the empirical evidence for such a rationale is mixed. Moreover, excess capacity has also been observed in experimental studies on capacityconstrained games where there is no entry (and therefore no entry-deterrence motive). This paper explores experimentally another rationale for excess capacity: rather than (in addition to) being a threat to (potential) entrants, excess capacity held by incumbents may constitute a valuable option to reap extra gains from competition with an inexperienced entrant, if he turns out to makes a mistake. In our experimental design we used the level of experience (the number of periods played) as a proxy for the level of rationality and matched subjects with different levels of experience. We find evidence of excess capacity decreasing with opponent’s experience. ? This paper is a sustantially revised version of a chapter of Le Coq and Sturluson’s 2003 Stockholm School of Economics Ph.D. thesis. It was before circulated as "Does Opponent’s experience matter?". The authors would like to thank Tore Ellingsen for his insightful comments in the project’s infancy, Urs Fischbacher for allowig us tousethez-TreesoftwareandHans-TheoNorman for technical help. We thank also seminar participants at the IIOC 2004 (Chicago), EARIE 2003 (Lausanne), SAET 2003 (Rhodos) for helpful comments. We gratefully acknowledge financial

Chloélecoq Jon; Thor Sturluson

2006-01-01T23:59:59.000Z

343

Towards experimentally testing the paradox of black hole information loss  

E-Print Network (OSTI)

Information about the collapsed matter in a black hole will be lost if Hawking radiations are truly thermal. Recent studies discover that information can be transmitted from a black hole by Hawking radiations, due to their spectrum deviating from exact thermality when back reaction is considered. In this paper, we focus on the spectroscopic features of Hawking radiation from a Schwarzschild black hole, contrasting the differences between the nonthermal and thermal spectra. Of great interest, we find that the energy covariances of Hawking radiations for the thermal spectrum are exactly zero, while the energy covariances are non-trivial for the nonthermal spectrum. Consequently, the nonthermal spectrum can be distinguished from the thermal one by counting the energy covariances of successive emissions, which provides an avenue towards experimentally testing the long-standing "information loss paradox".

Zhang, Baocheng; Zhan, Ming-sheng; You, Li; 10.1103/PhysRevD.87.044006

2013-01-01T23:59:59.000Z

344

Emerging of massive gauge particles in inhomogeneous local gauge transformations: replacement of Higgs mechanism  

E-Print Network (OSTI)

A generalized theory of gauge transformations is presented on the basis of the covariant Hamiltonian formalism of field theory, for which the covariant canonical field equations are equivalent to the Euler-Lagrange field equations. Similar to the canonical transformation theory of point dynamics, the canonical transformation rules for fields are derived from generating functions. Thus---in contrast to the usual Lagrangian description---the covariant canonical transformation formalism automatically ensures the mappings to preserve the action principle, and hence to be {\\em physical}. On that basis, we work out the theory of inhomogeneous local gauge transformations that generalizes the conventional local SU(N) gauge transformation theory. It is shown that massive gauge bosons naturally emerge in this description, which thus could supersede the Higgs mechanism.

Jürgen Struckmeier

2013-03-26T23:59:59.000Z

345

Simulations of Multiplicity Distributions and Perturbations to Nubar Data  

SciTech Connect

The objectives of this project are: (1) Use covariance data to generate random samples of energy dependent nubar; (2) Input the new samples of nubar into MCNP; (3) Run simulations and compare to experimental data; and (4) Repeat until a set of nubar that matches multiplicity distribution without significantly altering k{sub eff} is found. Some conclusions are: (1) Demonstrated that by adjusting nubar within covariance data can recreate multiplicity distributions correctly; (2) k{sub eff} was not changed that significantly, and more trials will likely generate a better result; (3) Can adjust FOM to produce a set of data that does what is desired; and (4) The covariances are tiny relative to the variances.

Bolding, Simon R. [Los Alamos National Laboratory

2013-01-14T23:59:59.000Z

346

The spinor field theory of the photon  

E-Print Network (OSTI)

I introduce a spinor field theory for the photon. The three-dimensional vector electromagnetic field and the four-dimensional vector potential are components of this spinor photon field. A spinor equation for the photon field is derived from Maxwell's equations,the relations between the electromagnetic field and the four-dimensional vector potential, and the Lorentz gauge condition. The covariant quantization of free photon field is done, and only transverse photons are obtained. The vacuum energy divergence does not occur in this theory. A covariant "positive frequency" condition is introduced for separating the photon field from its complex conjugate in the presence of the electric current and charge.

Ruo Peng Wang

2011-09-15T23:59:59.000Z

347

Gravitational energy-momentum and the Hamiltonian formulation of the teleparallel gravity  

E-Print Network (OSTI)

The transformation properties of the gravitational energy-momentum in the teleparallel gravity are analyzed. It is proved that the gravitational energy-momentum in the teleparallel gravity can be expressed in terms of the Lorentz gauge potential, and therefore is not covariant under local Lorentz transformations. On the other hand, it can also be expressed in terms of the translation gauge field strength, and therefore is covariant under general coordinate transformations. A simplified Hamiltonian formulation of the teleparallel gravity is given. Its constraint algebra has the same structure as that of general relativity, which indicates the equivalence between the teleparallel gravity and general relativity in the Hamiltonian formulation.

G. Y. Chee; Ye Zhang; Yongxin Guo

2001-06-15T23:59:59.000Z

348

Consumption risk and the cross section of expected returns  

E-Print Network (OSTI)

This paper evaluates the central insight of the consumption capital asset pricing model that an asset’s expected return is determined by its equilibrium risk to consumption. Rather than measure risk by the contemporaneous covariance of an asset’s return and consumption growth, we measure risk by the covariance of an asset’s return and consumption growth cumulated over many quarters following the return. While contemporaneous consumption risk explains little of the variation in average returns across the 25 Fama-French portfolios, our measure of ultimate consumption risk at a horizon of three years explains a large fraction of this variation. I.

Jonathan A. Parker; Christian Julliard; John Cochrane; Kent Daniel; Albina Danilova; Pierre-olivier Gourinchas; Sydney Ludvigson

2005-01-01T23:59:59.000Z

349

On the evolution equations for a self-gravitating charged scalar field  

E-Print Network (OSTI)

We consider a complex scalar field minimally coupled to gravity and to a U(1) gauge symmetry and we construct of a first order symmetric hyperbolic evolution system for the Einstein-Maxwell-Klein-Gordon system. Our analysis is based on a 1+3 tetrad formalism which makes use of the components of the Weyl tensor as one of the unknowns. In order to ensure the symmetric hyperbolicity of the evolution equations, implied by the Bianchi identity, we introduce a tensor of rank 3 corresponding to the covariant derivative of the Faraday tensor, and two tensors of rank 2 for the covariant derivative of the vector potential and the scalar field.

Daniela Pugliese; Juan A. Valiente Kroon

2013-01-03T23:59:59.000Z

350

Particle Energy Spectrum, Revisited from a Counting Statistics Perspective  

SciTech Connect

In nuclear science, gamma and neutron spectra are counted energy by energy, and then particle by particle. Until recently, few studies have been performed on how exactly those energy spectra are counted, or how those counts are correlated. Because of lack of investigation, cross section covariance and correlation matrices are usually estimated using perturbation method. We will discuss a statistical counting scheme that shall mimic the gamma and neutron counting process used in nuclear science. From this counting scheme, the cross section covariance and correlation can be statistically derived.

None

2012-07-28T23:59:59.000Z

351

Brief Calibration and estimation of redundant signals  

Science Conference Proceedings (OSTI)

This paper presents formulation and validation of an adaptive filter for real-time calibration of redundant signals consisting of sensor data and/or analytically derived measurements. The measurement noise covariance matrix is adjusted as a function ... Keywords: Adaptive filtering, Real-time control, Redundancy management, Sensor calibration, Signal estimation

Asok Ray; Shashi Phoha

2000-10-01T23:59:59.000Z

352

The Effect of Local Atmospheric Circulations on Daytime Carbon Dioxide Flux Measurements over a Pinus elliottii Canopy  

Science Conference Proceedings (OSTI)

The daytime net ecosystem exchange of CO2 (NEE) was measured in an even-aged slash pine plantation in northern Florida from 1999 to 2001 using the eddy covariance technique. In August 2000, two clear-cuts were formed approximately 1 km west of ...

H. W. Loescher; G. Starr; T. A. Martin; M. Binford; H. L. Gholz

2006-08-01T23:59:59.000Z

353

Hessian optimal design for image retrieval  

Science Conference Proceedings (OSTI)

Recently there has been a considerable interest in active learning from the perspective of optimal experimental design (OED). OED selects the most informative samples to minimize the covariance matrix of the parameters, so that the expected prediction ... Keywords: Active learning, Image retrieval, Regularization

Ke Lu; Jidong Zhao; Yue Wu

2011-06-01T23:59:59.000Z

354

Comparing Simulated and Measured Sensible and Latent Heat Fluxes over Snow under a Pine Canopy to Improve an Energy Balance Snowmelt Model  

Science Conference Proceedings (OSTI)

During the second year of the NASA Cold Land Processes Experiment (CLPX), an eddy covariance (EC) system was deployed at the Local Scale Observation Site (LSOS) from mid-February to June 2003. The EC system was located beneath a uniform pine ...

D. Marks; A. Winstral; G. Flerchinger; M. Reba; J. Pomeroy; T. Link; K. Elder

2008-12-01T23:59:59.000Z

355

Photonic portal to hidden sector and a parity-preserving option  

E-Print Network (OSTI)

In the case of previously proposed idea of photonic portal to hidden sector, the parity in this sector may be violated. We discuss here two new options within our model, where the parity is preserved. The first of them is not satisfactory, as not diplaying a full relativistic covariance. The second seems to be satisfactory.

Wojciech Krolikowski

2010-01-25T23:59:59.000Z

356

How Long Is Long Enough When Measuring Fluxes and Other Turbulence Statistics?  

Science Conference Proceedings (OSTI)

It is determined how long a time series must be to estimate covariances and moments up to fourth order with a specified statistical significance. For a given averaging time T there is a systematic difference between the true flux or moment and ...

D. H. Lenschow; J. Mann; L. Kristensen

1994-06-01T23:59:59.000Z

357

EOFs of One-Dimensional Cyclostationary Time Series: Computations, Examples, and Stochastic Modeling  

Science Conference Proceedings (OSTI)

Many climatic time series seem to be a mixture of unpredictable fluctuations and changes that occur at a known frequency, as in the case of the annual cycle. Such a time series is called a cyclostationary process. The lagged covariance statistics ...

Kwang-Y. Kim; Gerald R. North; Jianping Huang

1996-04-01T23:59:59.000Z

358

Boundary-Layer Meteorol (2008) 127:273292 DOI 10.1007/s10546-007-9254-x  

E-Print Network (OSTI)

of the Reynolds or temporally averaged heat flux at a grid point from the horizontally averaged total heat flux experiments that the eddy covariance heat fluxes are systematically underestimated as compared magnitude and its horizontal and vertical distributions. The flux imbalance of heat and the bottom­up tracer

Lee, Xuhui

359

Combining quasi and empirical likelihoods in generalized linear models with missing responses  

Science Conference Proceedings (OSTI)

By only specifying the conditional mean and variance functions of the response variable given covariates, the quasi-likelihood can produce valid semiparametric inference for regression parameter in generalized linear models (GLMs). However, in many studies, ... Keywords: 62F12, 62F30, 62G10, Auxiliary information, Combined quasi and empirical likelihood, Generalized linear models, Missing responses, Wilks' theorem

Tianqing Liu; Xiaohui Yuan

2012-10-01T23:59:59.000Z

360

Jackknife empirical likelihood tests for error distributions in regression models  

Science Conference Proceedings (OSTI)

Regression models are commonly used to model the relationship between responses and covariates. For testing the error distribution, some classical test statistics such as Kolmogorov-Smirnov test and Cramer-von-Mises test suffer from the complicated limiting ... Keywords: Goodness-of-fit test, Jackknife empirical Likelihood method, Regression model, primary

Huijun Feng; Liang Peng

2012-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Multivariate lag-windows and group representations  

Science Conference Proceedings (OSTI)

Symmetries of the auto-cumulant function (a generalization of the auto-covariance function) of a kth-order stationary time series are derived through a connection with the symmetric group of degree k. Using the theory of group representations, symmetries ... Keywords: 20C30, 37M10, Group representations, Higher-order spectra, Multivariate lag-windows, Symmetry group

Arthur Berg

2008-11-01T23:59:59.000Z

362

Quantum mechanics and gravity as preclusion principles of four dimensional geometries  

E-Print Network (OSTI)

The goal of this paper is to employ a "preclusion principle" originally suggested by Rafael Sorkin in order to come up with a relativistically covariant model of quantum mechanics and gravity. Space-time is viewed as geometry as opposed to dynamics, and "unwanted" histories in that geometry are precluded.

Roman Sverdlov

2008-10-01T23:59:59.000Z

363

Nonparametric combinatorial sequence models  

Science Conference Proceedings (OSTI)

This work considers biological sequences that exhibit combinatorial structures in their composition: groups of positions of the aligned sequences are "linked" and covary as one unit across sequences. If multiple such groups exist, complex interactions ... Keywords: Chinese restaurant franchise, Chinese restaurant process, MHC binding, mixture models, sequence models

Fabian L. Wauthier; Michael I. Jordan; Nebojsa Jojic

2011-03-01T23:59:59.000Z

364

O P I N I O N Changing the way we think about global change research  

E-Print Network (OSTI)

laboratory, chlorophyll fluorescence, coral reefs, experimental ecosystem science, global change, stable that the imbalance of metabolism led to an alarming O2 deficit and the project was doomed, so far as sustainable? How does covariance of key parameters, such as the projected more rapid increase in night vs. day

365

Austral Summer Teleconnections of Indo-Pacific Variability: Their Nonlinearity and Impacts on Australian Climate  

Science Conference Proceedings (OSTI)

In austral summer, El Niño–Southern Oscillation (ENSO) covaries with the Indian Ocean Basin Mode (IOBM) and with the southern annular mode (SAM). The present study addresses how the IOBM and the SAM modulate the impact of ENSO on Australia. The ...

Wenju Cai; Peter van Rensch

2013-05-01T23:59:59.000Z

366

Brief paper: Suboptimal control of linear stochastic multivariable systems with unknown parameters  

Science Conference Proceedings (OSTI)

An algorithm is proposed for suboptimal control of linear multivariable systems with unknown parameters and output noise covariances. This algorithm is based on the idea of explicitly separating the functions of identification, estimation and control. ... Keywords: Kalman filters, Multivariable control systems, canonical forms, controllability, discrete time systems, observability, parameter estimation, state estimation, state space methods, stochastic control

H. El-Sherief; N. K. Sinha

1982-01-01T23:59:59.000Z

367

Asymptotic distribution of Wishart matrix for block-wise dispersion of population eigenvalues  

Science Conference Proceedings (OSTI)

This paper deals with the asymptotic distribution of Wishart matrix and its application to the estimation of the population matrix parameter when the population eigenvalues are block-wise infinitely dispersed. We show that the appropriately normalized ... Keywords: Stein's loss, 62C20, 62H10, Asymptotic risk, Covariance matrix, Quadratic loss, Wishart distribution

Yo Sheena; Akimichi Takemura

2008-04-01T23:59:59.000Z

368

A Wavelet-Based Reduced Rank Kalman Filter for Assimilation of Stratospheric Chemical Tracer Observations  

Science Conference Proceedings (OSTI)

A suboptimal Kalman filter system that evolves error covariances in terms of a truncated set of wavelet coefficients has been developed for the assimilation of chemical tracer observations of CH4. The truncation is carried out in such a way that ...

Ludovic Auger; Andrew V. Tangborn

2004-05-01T23:59:59.000Z

369

Geometry of interactions in complex bodies  

E-Print Network (OSTI)

We analyze geometrical structures necessary to represent bulk and surface interactions of standard and substructural nature in complex bodies. Our attention is mainly focused on the influence of diffuse interfaces on sharp discontinuity surfaces. In analyzing this phenomenon, we prove the covariance of surface balances of standard and substructural interactions.

Chiara de Fabriitis; Paolo Maria Mariano

2004-06-18T23:59:59.000Z

370

Impacts of Initial Estimate and Observation Availability on Convective-Scale Data Assimilation with an Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

The ensemble Kalman filter (EnKF) uses an ensemble of short-range forecasts to estimate the flow-dependent background error covariances required in data assimilation. The feasibility of the EnKF for convective-scale data assimilation has been ...

F. Zhang; Chris Snyder; Juanzhen Sun

2004-05-01T23:59:59.000Z

371

Inverse scattering problem with isobars  

SciTech Connect

The inverse scattering problem is solved for a covariant, isobar-dominated scattering amplitude (including inelasticity). Application is made to the ..pi..N P/sub 33/ channel, with the ..pi..N ..delta.. vertex function and isobar bare mass as results.

Londergan, J.T.; Moniz, E.J.

1977-08-01T23:59:59.000Z

372

Limited-Area Ensemble-Based Data Assimilation  

Science Conference Proceedings (OSTI)

Ensemble-based data assimilation is a state estimation technique that uses short-term ensemble forecasts to estimate flow-dependent background error covariance and is best known by varying forms of ensemble Kalman filters (EnKFs). The EnKF has ...

Zhiyong Meng; Fuqing Zhang

2011-07-01T23:59:59.000Z

373

1512 IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 21, NO. 4, NOVEMBER 2006 Managing Price Risk in a Multimarket Environment  

E-Print Network (OSTI)

1517 Fig. 2. Monthly spot price of natural gas. TABLE I DETERMINISTIC VERSUS RANDOM (GAS PRICES) , (95 on allocation ratios (coal prices are deterministic or random). TABLE III COVARIANCE AMONG TRANSACTIONS (GAS://www.ucei.berkeley.edu/datamine/ uceidata/. [18] Energy Information Administration website. [Online]. Available: http://www.eia.doe.gov/oil_gas/natural_gas/info_glance/prices

Tam, Vincent W. L.

374

A novel algorithm for segmenting fruit from unorganized point clouds  

Science Conference Proceedings (OSTI)

This paper proposes an efficient and robust four-step process to extracting fruit shape from background. At first, point clouds is divided into octree cells by an adaptive subdivision; Second, converting teach octree cell into a splat and approximating ... Keywords: MLS, PCA, covariance analysis, point cloud, segmentation, splat

Hui-jun Yang; Dong-jian He; Zhi-yi Zhang; Xin Wang

2011-12-01T23:59:59.000Z

375

Fast and exact synthesis of stationary multivariate Gaussian time series using circulant embedding  

Science Conference Proceedings (OSTI)

A fast and exact procedure for the numerical synthesis of stationary multivariate Gaussian time series with a priori prescribed and well controlled auto- and cross-covariance functions is proposed. It is based on extending the circulant embedding technique ... Keywords: Circulant embedding, Multivariate Gaussian series, Numerical synthesis, Stationarity, Time-reversibility

Hannes Helgason; Vladas Pipiras; Patrice Abry

2011-05-01T23:59:59.000Z

376

Small Quarkonium states in an anisotropic QCD plasma  

E-Print Network (OSTI)

We determine the hard-loop resummed propagator in an anisotropic QCD plasma in general covariant gauges and define a potential between heavy quarks from the Fourier transform of its static limit. We find that the potential exhibits angular dependence and that binding of very small quarkonium states is stronger than in an isotropic plasma.

Yun Guo

2008-05-16T23:59:59.000Z

377

A New Drag Relation for Aerodynamically Rough Flow over the Ocean  

Science Conference Proceedings (OSTI)

From almost 7000 near-surface eddy-covariance flux measurements over the sea, the authors deduce a new air–sea drag relation for aerodynamically rough flow:Here u* is the measured friction velocity, and UN10 is the neutral-stability wind speed at ...

Edgar L Andreas; Larry Mahrt; Dean Vickers

2012-08-01T23:59:59.000Z

378

Over the past decade we have been experiencing  

E-Print Network (OSTI)

, planted hardstem bulrush or tule levees in the Delta, levee maintenance is costly and flooding by hundreds of studies that used small chambers. From a historical per- spective, these new instru- ments the full annual cycle of methane fluxes with eddy covariance at Siikaneva. "Has this been done before

379

Bayesian multiple response kernel regression model for high dimensional data and its practical applications in near infrared spectroscopy  

Science Conference Proceedings (OSTI)

Non-linear regression based on reproducing kernel Hilbert space (RKHS) has recently become very popular in fitting high-dimensional data. The RKHS formulation provides an automatic dimension reduction of the covariates. This is particularly helpful when ... Keywords: Bayesian prediction, Laplace distribution, Metropolis-Hastings algorithm, Near infrared spectroscopy, Nonlinear regression, Reproducing kernel Hilbert space, Vapnik's ?-insensitive loss

Sounak Chakraborty

2012-09-01T23:59:59.000Z

380

An Adjoint-Based Adaptive Ensemble Kalman Filter  

Science Conference Proceedings (OSTI)

A new hybrid ensemble Kalman filter/four-dimensional variational data assimilation (EnKF/4D-VAR) approach is introduced to mitigate background covariance limitations in the EnKF. The work is based on the adaptive EnKF (AEnKF) method, which bears a ...

Hajoon Song; Ibrahim Hoteit; Bruce D. Cornuelle; Xiaodong Luo; Aneesh C. Subramanian

2013-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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.


381

Modeling the Loss Distribution  

Science Conference Proceedings (OSTI)

In this paper, we focus on modeling and predicting the loss distribution for credit risky assets such as bonds and loans. We model the probability of default and the recovery rate given default based on shared covariates. We develop a new class of default ... Keywords: Basel II, default prediction, loss distribution, recovery rates

Sudheer Chava; Catalina Stefanescu; Stuart Turnbull

2011-07-01T23:59:59.000Z

382

How Important Is Air–Sea Coupling in ENSO and MJO Evolution?  

Science Conference Proceedings (OSTI)

The effect of air–sea coupling on tropical climate variability is investigated in a coupled linear inverse model (LIM) derived from the simultaneous and 6-day lag covariances of observed 7-day running mean departures from the annual cycle. The ...

Matthew Newman; Prashant D. Sardeshmukh; Cécile Penland

2009-06-01T23:59:59.000Z

383

Influence of the Eurasian snow cover on the Indian summer monsoon variability in observed climatologies and CMIP3  

E-Print Network (OSTI)

Influence of the Eurasian snow cover on the Indian summer monsoon variability in observed using sev- eral statistical tools including a maximum covariance analysis. The snow­monsoon relationship between an east­west snow dipole over Eurasia and the Indian summer monsoon precipitation. However, our

384

Influence of the Eurasian snow cover on the Indian summer monsoon variability in observed climatologies and CMIP3  

E-Print Network (OSTI)

Influence of the Eurasian snow cover on the Indian summer monsoon variability in observed statistical tools including a maximum covariance analysis. The snow­monsoon relationship is explored using an east­west snow dipole over Eurasia and the Indian summer monsoon precipitation. However, our results

385

History of The University of Chicago Laboratory Schools  

E-Print Network (OSTI)

#12;156 Mosh« Burstein lind DIII'id Wool preference (Bultman & Faeth. 19S(1), but female dis as an example of positive covariance of preference and performance (Price, 19S4: Whitham, 1992). Wool & Manheim trees in Israel (Wertheim, 1954; Bodenheimer & Swirski , 1957: Koach & Wool, 1977). The life cycle

Pritchard, Jonathan

386

A study of variable selection using g-prior distribution with ridge parameter  

Science Conference Proceedings (OSTI)

In the Bayesian stochastic search variable selection framework, a common prior distribution for the regression coefficients is the g-prior of Zellner. However there are two standard cases where the associated covariance matrix does not exist and the ... Keywords: Bayesian Lasso, Generalized linear mixed model, Metropolis-within-Gibbs algorithm, Probit mixed regression model, Ridge parameter, Stochastic search variable selection, Zellner prior

M. Baragatti; D. Pommeret

2012-06-01T23:59:59.000Z

387

Classification and forecasting of load curves Nolwen Huet  

E-Print Network (OSTI)

on up to stabilisation of the clusters. Finally, the load profiles are predicted by covariance analysis of electricity customer uses. This load curve is only available for customers with automated meter readingClassification and forecasting of load curves Nolwen Huet Abstract The load curve, which gives

Cuesta, Juan Antonio

388

Is cognition a matter of representations? Emulation, teleology, and time-keeping in biological systems  

Science Conference Proceedings (OSTI)

Contemporary literature distinguishes two ways to defend the claim that cognition is a matter of representations: first, cognition involves representation-hungry tasks; second, cognition involves a complex form of informational covariation between subcomponents ... Keywords: Cognition, circadian oscillator, closed-loop architecture, emulation theory, representation, tropism

Ángel García Rodríguez; Paco Calvo Garzón

2010-10-01T23:59:59.000Z

389

Maximum likelihood estimation of Gaussian mixture models using stochastic search  

Science Conference Proceedings (OSTI)

Gaussian mixture models (GMM), commonly used in pattern recognition and machine learning, provide a flexible probabilistic model for the data. The conventional expectation-maximization (EM) algorithm for the maximum likelihood estimation of the parameters ... Keywords: Covariance parametrization, Expectation-maximization, Gaussian mixture models, Identifiability, Maximum likelihood estimation, Particle swarm optimization, Stochastic search

Ça?lar Ar?; Selim Aksoy; Orhan Ar?kan

2012-07-01T23:59:59.000Z

390

Approximate and efficient methods to assess error fields in spatial gridding with DIVA (Data Interpolating Variational Analysis)  

Science Conference Proceedings (OSTI)

We present new approximate methods to provide error fields for the spatial analysis tool Diva. It is first shown how to replace the costly analysis of a large number of covariance functions by a single analysis for quick error computations. Then ...

Jean-Marie Beckers; Alexander Barth; Charles Troupin; Aida Alvera-Azcárate

391

A Rapid Method of Computing Empirical Orthogonal Functions from a Large Dataset  

Science Conference Proceedings (OSTI)

A rapid method of computing the EOFs for a problem with a large covariance matrix is presented. The resulting EOFs are not the “true” ones because they do not guarantee that the maximum variance is explained in the dependent sample. However, in ...

Juhani Rinne; Simo Järvenoja

1986-12-01T23:59:59.000Z

392

Simulation and sensitivity analysis of carbon storage and fluxes in the New Jersey Pinelands  

Science Conference Proceedings (OSTI)

A major challenge in modeling the carbon dynamics of vegetation communities is the proper parameterization and calibration of eco-physiological variables that are critical determinants of the ecosystem process-based model behavior. In this study, we ... Keywords: Carbon dynamics, Eddy covariance tower, Fire effects, GEP, NEE, The extended Fourier amplitude sensitivity test approach (EFAST), WxBGC model

Zewei Miao; Richard G. Lathrop, Jr.; Ming Xu; Inga P. La Puma; Kenneth L. Clark; John Hom; Nicholas Skowronski; Steve Van Tuyl

2011-09-01T23:59:59.000Z

393

231A. Hernndez-Sols et al. / Annals of Nuclear Energy 57 (2013) 230245 Lattice calculations use nuclear libraries as input basis data,  

E-Print Network (OSTI)

be used for any reactor physics cal culations. Once evaluated, the nuclear data are added in a specific assemblies), and nuclear models and theory. The covariance is given with respect to point wise cross section#12;231A. Hernández-Solís et al. / Annals of Nuclear Energy 57 (2013) 230­245 Lattice calculations

Demazière, Christophe

394

www.elsevier.nl/locate/jorganchem Journal of Organometallic Chemistry 585 (1999) 275284  

E-Print Network (OSTI)

1994). If deployed as a coordinated network of measurements sites, the eddy covariance method has of measuring fluxes from every patch on earth, nor do we intend to. On the other hand, this coordinated network of carbon dioxide and water vapor fluxes due to changes in insolation, tempera- ture

Girolami, Gregory S.

395

The relativistic velocity addition law optimizes a forecast gambler's profit  

E-Print Network (OSTI)

We extend the projective covariant bookmaker's bets model to the forecasting gamblers case. The probability of correctness of forecasts shifts probabilities of branching. The formula for the shift of probabilities leads to the velocity addition rule of the special theory of relativity. In the absence of information about bookmaker's wagers the stochastic logarithmic rates completely determines the optimal stakes of forecast gambler.

Piotrowski, Edward W

2007-01-01T23:59:59.000Z

396

Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 00: 115 (0000) Controlling model error of underdamped forecast models in  

E-Print Network (OSTI)

) Controlling model error of underdamped forecast models in sparse observational networks using a variance@maths.usyd.edu.au The problem of controlling covariance overestimation due to underdamped forecast models and sparsity the initial conditions and forecast model and to combat the associated forecast error and flow

Gottwald, Georg A.

397

H.C. PAUL Lee Department of Physics and Institute for Systems Biology and Bioinformatics  

E-Print Network (OSTI)

. H.C. Lee "Neutral current and the nuclear scattering of reactor antineutrinos" Nucl. Phys. A294 to Kaluza-Klein Theories" (Book) (World Scientific, 1984), 320pp. H.C. Lee "Nuclear charge, convection, "Quantum holonomy in three-dimensional general covariant field theory and link invariant" Phys. Rev. D56

Lee, H.C. Paul

398

Brief paper: Estimation of the disturbance structure from data using semidefinite programming and optimal weighting  

Science Conference Proceedings (OSTI)

Designing a state estimator for a linear state-space model requires knowledge of the characteristics of the disturbances entering the states and the measurements. In [Odelson, B. J., Rajamani, M. R., & Rawlings, J. B. (2006). A new autocovariance least ... Keywords: Covariance estimation, Minimum independent disturbances, Minimum variance estimation, Semidefinite programming, State estimation

Murali R. Rajamani; James B. Rawlings

2009-01-01T23:59:59.000Z

399

Fast alogorithms for Bayesian uncertainty quantification in large-scale linear inverse problems based on low-rank partial Hessian approximations  

SciTech Connect

We consider the problem of estimating the uncertainty in large-scale linear statistical inverse problems with high-dimensional parameter spaces within the framework of Bayesian inference. When the noise and prior probability densities are Gaussian, the solution to the inverse problem is also Gaussian, and is thus characterized by the mean and covariance matrix of the posterior probability density. Unfortunately, explicitly computing the posterior covariance matrix requires as many forward solutions as there are parameters, and is thus prohibitive when the forward problem is expensive and the parameter dimension is large. However, for many ill-posed inverse problems, the Hessian matrix of the data misfit term has a spectrum that collapses rapidly to zero. We present a fast method for computation of an approximation to the posterior covariance that exploits the lowrank structure of the preconditioned (by the prior covariance) Hessian of the data misfit. Analysis of an infinite-dimensional model convection-diffusion problem, and numerical experiments on large-scale 3D convection-diffusion inverse problems with up to 1.5 million parameters, demonstrate that the number of forward PDE solves required for an accurate low-rank approximation is independent of the problem dimension. This permits scalable estimation of the uncertainty in large-scale ill-posed linear inverse problems at a small multiple (independent of the problem dimension) of the cost of solving the forward problem.

Akcelik, Volkan [ORNL; Flath, Pearl [University of Texas, Austin; Ghattas, Omar [University of Texas, Austin; Hill, Judith C [ORNL; Van Bloemen Waanders, Bart [Sandia National Laboratories (SNL); Wilcox, Lucas [University of Texas, Austin

2011-01-01T23:59:59.000Z

400

Annual Progress Report Period May 1, 2010April 30, 2011  

E-Print Network (OSTI)

(PAR, T, RH, PPT) and a newly installed within-canopy eddy co-variance measurement system. All measurement system (Michael Goulden, UCI). We added an additional set of AMR and soil sensor nodes at the La Observing Systems (NAMOS), employs coordinated measurements between stationary sensing nodes and robotic

Soatto, Stefano

Note: This page contains sample records for the topic "leventis theo covary" 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.


401

Reducing Water Imbalance in Land Data Assimilation: Ensemble Filtering without Perturbed Observations  

Science Conference Proceedings (OSTI)

It is well known that the ensemble Kalman filter (EnKF) requires updating each ensemble member with perturbed observations in order to produce the proper analysis-error covariances. While increased accuracy in a mean square sense may be preferable ...

M. Tugrul Yilmaz; Timothy DelSole; Paul R. Houser

2012-02-01T23:59:59.000Z

402

Asymptotic normality and Berry-Esseen results for conditional density estimator with censored and dependent data  

Science Conference Proceedings (OSTI)

In this paper we derive the asymptotic normality and a Berry-Esseen type bound for the kernel conditional density estimator proposed in Ould-Said and Cai (2005) [26] when the censored observations with multivariate covariates form a stationary @a-mixing ... Keywords: ?-mixing, 62G07, 62G20, Asymptotic normality, Berry-Esseen type bound, Censored data, Conditional density

Han-Ying Liang; Liang Peng

2010-05-01T23:59:59.000Z

403

Baryon Fluctuations in High Energy Nuclear Collisions  

E-Print Network (OSTI)

We propose that dramatic changes in the variances and covariance of protons and antiprotons can result if baryons approach chemical equilibrium in nuclear collisions at RHIC. To explore how equilibration alters these fluctuations, we formulate both equilibrium and nonequilibrium hadrochemical descriptions of baryon evolution. Contributions to fluctuations from impact parameter averaging and finite acceptance in nuclear collisions are numerically simulated.

Sean Gavin; Claude Pruneau

1999-07-09T23:59:59.000Z

404

Semiparametric regression with shape-constrained penalized splines  

Science Conference Proceedings (OSTI)

In semiparametric regression models, penalized splines can be used to describe complex, non-linear relationships between the mean response and covariates. In some applications it is desirable to restrict the shape of the splines so as to enforce properties ... Keywords: Linear mixed model, MCMC, Shape constraint, Spline, Truncated multivariate normal

Martin L. Hazelton; Berwin A. Turlach

2011-10-01T23:59:59.000Z

405

Evaluated Nuclear (reaction) Data from the Evaluated Nuclear Data File (ENDF)  

DOE Data Explorer (OSTI)

The current version is ENDF/B VII.0, released in 2006. Users can search ENDF via specialized interfaces, browse sub-libraries or download them as zipped files. Data plots can be generated through the Sigma interface. The ENDF web page also provides access to covariance data processing and plots. (Specialized Interface)

None

406

A Sequential Ensemble Kalman Filter for Atmospheric Data Assimilation  

Science Conference Proceedings (OSTI)

An ensemble Kalman filter may be considered for the 4D assimilation of atmospheric data. In this paper, an efficient implementation of the analysis step of the filter is proposed. It employs a Schur (elementwise) product of the covariances of the ...

P. L. Houtekamer; Herschel L. Mitchell

2001-01-01T23:59:59.000Z

407

Ensemble Data Assimilation without Perturbed Observations  

Science Conference Proceedings (OSTI)

The ensemble Kalman filter (EnKF) is a data assimilation scheme based on the traditional Kalman filter update equation. An ensemble of forecasts are used to estimate the background-error covariances needed to compute the Kalman gain. It is known ...

Jeffrey S. Whitaker; Thomas M. Hamill

2002-07-01T23:59:59.000Z

408

Carbon Dioxide Exchange in an Irrigated Agricultural Field within an Oasis, Northwest China  

Science Conference Proceedings (OSTI)

Continuous eddy covariance measurements of CO2, water vapor, and heat fluxes were obtained from a maize field within an oasis in northwest China from 1 May 2008 to 30 April 2009. The experimental setup used was shown to provide reliable flux ...

Xi-Bin Ji; Wen-Zhi Zhao; Er-Si Kang; Zhi-Hui Zhang; Bo-Wen Jin; Li-Wen Zhao

2011-11-01T23:59:59.000Z

409

Deep structure from a geometric point of view  

Science Conference Proceedings (OSTI)

The geometry of “empty” scale space is investigated. By virtue of the proposed geometric axioms the generating PDE, the linear isotropic heat equation, can be presented in covariant, or geometrical form. The postulate of a metric for scale ... Keywords: deep structure, foveal scale space, homogeneous scale space, scale space geometry

Luc Florack

2005-06-01T23:59:59.000Z

410

Improving the estimation of Kendall's tau when censoring affects only one of the variables  

Science Conference Proceedings (OSTI)

This paper considers the estimation of Kendall's tau for bivariate data (X,Y) when only Y is subject to right-censoring. Although @t is estimable under weak regularity conditions, the estimators proposed by Brown et al. [1974. Nonparametric tests of ... Keywords: Censoring, Conditional distribution, Copula, Covariate, Generalized Kaplan-Meier estimator, Kendall's tau, Lifetime data

David Beaudoin; Thierry Duchesne; Christian Genest

2007-08-01T23:59:59.000Z

411

Asymptotically efficient estimation of the conditional expected shortfall  

Science Conference Proceedings (OSTI)

A procedure for efficient estimation of the trimmed mean of a random variable conditional on a set of covariates is proposed. For concreteness, the focus is on a financial application where the trimmed mean of interest corresponds to the conditional ... Keywords: Asymptotic efficiency, Expected shortfall, Quantile regression

Samantha Leorato; Franco Peracchi; Andrei V. Tanase

2012-04-01T23:59:59.000Z

412

Long-Term Carbon Dioxide Fluxes from a Very Tall Tower in a Northern Forest: Flux Measurement Methodology  

Science Conference Proceedings (OSTI)

Methodology for determining fluxes of CO2 and H2O vapor with the eddy-covariance method using data from instruments on a 447-m tower in the forest of northern Wisconsin is addressed. The primary goal of this study is the validation of the methods ...

Bradford W. Berger; Kenneth J. Davis; Chuixiang Yi; Peter S. Bakwin; Cong Long Zhao

2001-04-01T23:59:59.000Z

413

Carbon Dioxide Emissions of the City Center of Firenze, Italy: Measurement, Evaluation, and Source Partitioning  

Science Conference Proceedings (OSTI)

An eddy covariance station was installed in the city center of Firenze, Italy, to measure carbon fluxes at half-hourly intervals over a mostly homogeneous urban area. Carbon dioxide (CO2) emission observations made over an initial period of 3.5 ...

A. Matese; B. Gioli; F. P. Vaccari; A. Zaldei; F. Miglietta

2009-09-01T23:59:59.000Z

414

Intelligent sea transportation system postoptimal analysis  

Science Conference Proceedings (OSTI)

A procedure for the ship dynamic positioning postoptimal analysis in Intelligent Sea Transportation System Optimization is proposed. The dynamic positioning control system design is based on the optimal constrained covariance control (OC3). ... Keywords: LQG control, dynamic positioning, intelligent transportation system, mathematical modelling, optimization problems, postoptimal analysis, robust control

Sadko Mandžuka; Ivan Bošnjak; Ljupko Šimunovic

2009-07-01T23:59:59.000Z

415

Enhancement of Evaporation from a Large Northern Lake by the Entrainment of Warm, Dry Air  

Science Conference Proceedings (OSTI)

The turbulent exchange of water vapor and heat were measured above Great Slave Lake, Northwest Territories, Canada, using the eddy covariance method for most of the ice-free period in 1997, 1998, and 1999. In all years, evaporation tended to ...

Peter D. Blanken; Wayne R. Rouse; William M. Schertzer

2003-08-01T23:59:59.000Z

416

Correlated Errors in the COBE DMR Sky Maps  

E-Print Network (OSTI)

The {\\it COBE} DMR sky maps contain low-level correlated noise. We obtain estimates of the amplitude and pattern of the correlated noise from three techniques: angular averages of the covariance matrix, Monte Carlo simulations of two-point correlation functions, and direct analysis of the DMR maps. The results from the three methods are mutually consistent. The noise covariance matrix of a DMR sky map is diagonal to an accuracy of better than 1\\%. For a given sky pixel, the dominant noise covariance occurs with the ring of pixels at an angular separation of $60 \\deg$ due to the $60 \\deg$ separation of the DMR horns. The mean covariance at $60 \\deg$ is $0.45\\% ^{+0.18}_{-0.14}$ of the mean variance. Additionally, the variance in a given pixel is $0.7\\%$ greater than would be expected from a single beam experiment with the same noise properties. Auto-correlation functions suffer from a $\\sim 1.5\\; \\sigma$ positive bias at $60 \\deg$ while cross-correlations have no bias. Published {\\it COBE} DMR results are not significantly affected by correlated noise. COBE pre-print 94-

C. H. Lineweaver; G. F. Smoot; C. L. Bennett; E. L. Wright; L. Tenorio; A. Kogut; P. B. Keegstra; G. Hinshaw; A. J. Banday

1994-03-10T23:59:59.000Z

417

Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions  

SciTech Connect

Emission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options. It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other prod-ucts. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls. Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive mate-rial for efficiently reducing formaldehyde in dryer emissions. A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing. Fines release a disproportionate large quantity of HAPs, and it has been shown both theo-retically and in full-scale work that particles smaller than 400 ���µm are principally responsible. Georgia-Pacific is considering green-screening their furnish at several of their mills in order to remove these particles and reduce their treatment costs.

Sujit Banerjee

2005-10-31T23:59:59.000Z

418

Electric/magnetic duality for chiral gauge theories with anomaly cancellation  

E-Print Network (OSTI)

We show that 4D gauge theories with Green-Schwarz anomaly cancellation and possible generalized Chern-Simons terms admit a formulation that is manifestly covariant with respect to electric/magnetic duality transformations. This generalizes previous work on the symplectically covariant formulation of anomaly-free gauge theories as they typically occur in extended supergravity, and now also includes general theories with (pseudo-)anomalous gauge interactions as they may occur in global or local N=1 supersymmetry. This generalization is achieved by relaxing the linear constraint on the embedding tensor so as to allow for a symmetric 3-tensor related to electric and/or magnetic quantum anomalies in these theories. Apart from electric and magnetic gauge fields, the resulting Lagrangians also feature two-form fields and can accommodate various unusual duality frames as they often appear, e.g., in string compactifications with background fluxes.

Jan De Rydt; Torsten T. Schmidt; Mario Trigiante; Antoine Van Proeyen; Marco Zagermann

2008-08-15T23:59:59.000Z

419

User Guide for the STAYSL PNNL Suite of Software Tools  

SciTech Connect

The STAYSL PNNL software suite provides a set of tools for working with neutron activation rates measured in a nuclear fission reactor, an accelerator-based neutron source, or any neutron field to determine the neutron flux spectrum through a generalized least-squares approach. This process is referred to as neutron spectral adjustment since the preferred approach is to use measured data to adjust neutron spectra provided by neutron physics calculations. The input data consist of the reaction rates based on measured activities, an initial estimate of the neutron flux spectrum, neutron activation cross sections and their associated uncertainties (covariances), and relevant correction factors. The output consists of the adjusted neutron flux spectrum and associated covariance matrix, which is useful for neutron dosimetry and radiation damage calculations.

Greenwood, Lawrence R.; Johnson, Christian D.

2013-02-27T23:59:59.000Z

420

Deformed oscillator algebras and QFT in {kappa}-Minkowski spacetime  

SciTech Connect

In this paper, we study the deformed statistics and oscillator algebras of quantum fields defined in {kappa}-Minkowski spacetime. The twisted flip operator obtained from the twist associated with the star product requires an enlargement of the Poincare algebra to include the dilatation generators. Here we propose a novel notion of a fully covariant flip operator and show that to the first order in the deformation parameter it can be expressed completely in terms of the Poincare generators alone. The R matrices corresponding to the twisted and the covariant flip operators are compared up to first order in the deformation parameter and they are shown to be different. We also construct the deformed algebra of the creation and annihilation operators that arise in the mode expansion of a scalar field in {kappa}-Minkowski spacetime. We obtain a large class of such new deformed algebras which, for certain choice of realizations, reduce to results known in the literature.

Govindarajan, T. R.; Gupta, Kumar S.; Harikumar, E.; Meljanac, S.; Meljanac, D. [Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113 (India); Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700064 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)

2009-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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.


421

Singularity-free two-body equation with confining interactions in momentum space  

E-Print Network (OSTI)

We are developing a covariant model for all mesons that can be described as quark-antiquark bound states in the framework of the Covariant Spectator Theory (CST) in Minkowski space. The kernel of the bound-state equation contains a relativistic generalization of a linear confining potential which is singular in momentum space and makes its numerical solution more difficult. The same type of singularity is present in the momentum-space Schr\\"odinger equation, which is obtained in the nonrelativistic limit. We present an alternative, singularity-free form of the momentum-space Schr\\"odinger equation which is much easier to solve numerically and which yields accurate and stable results. The same method will be applied to the numerical solution of the CST bound-state equations.

Alfred Stadler; Sofia Leitão; M. T. Peña; Elmar P. Biernat

2013-11-27T23:59:59.000Z

422

New Gauge Conditions in General Relativity: What Can We Learn from Them?  

E-Print Network (OSTI)

The construction of conformally invariant gauge conditions for Maxwell and Einstein theories on a manifold M is found to involve two basic ingredients. First, covariant derivatives of a linear gauge (e.g. Lorenz or de Donder), completely contracted with the tensor field representing the metric on the vector bundle of the theory. Second, the addition of a compensating term, obtained by covariant differentiation of a suitable tensor field built from the geometric data of the problem. If the manifold M is endowed with an m-dimensional positive-definite metric g, the existence theorem for such a gauge in gravitational theory can be proved. If the metric g is Lorentzian, which corresponds to general relativity, some technical steps are harder, but one has again to solve integral equations on curved space-time to be able to impose such gauges.

Giampiero Esposito; Cosimo Stornaiolo

1999-10-08T23:59:59.000Z

423

QUANTIZATION OF THE GENERAL THEORY OF RELATIVITY  

SciTech Connect

It is possible to quantize most classical field theories by identifying the group of canonical transformations that maintain the covariance properties with a group of unitary transformations in Hilbert space that has the same commutator algebra. The computators among the canonical field variables are equal to the Dirac delta function times a factor that may be zero. But in the general theory of relativity the classical group of the canonical transformations that maintain the covariance properties of the theory has an invariance subgroup. The ambiguities thus introduced by the usual process of quantization can be avoided by the use of the Dirac quantization procedure for theories with constraints. An analogy between classical Dirac brackets and commutators is established, and an intrinsic coordinate system is fixed. This choice of local intrinsic coordinate conditions leads to commutators among the canonical field variables of the general theory of relativity that depend upon the Dirac delta function and its flrst seven derivatives. (auth)

Boardman, J.M.

1962-01-01T23:59:59.000Z

424

Particle with spin S=3/2 in Riemannian space-time  

E-Print Network (OSTI)

Equations for 16-component vector-bispinor field, originated from Rarita-Schwinger Lagrangian for spin 3/2 field extended to Riemannian space-time are investigated. Additional general covariant constrains for the field are produced, which for some space-time models greatly simplify original wave equation. Peculiarities in description of the massless spin 3/2 field are specified. In the flat Minkowski space for massless case there exist gauge invariance of the main wave equation, which reduces to possibility to produce a whole class of trivial solutions in the the form of 4-gradient of arbitrary (gauge) bispinor function, \\Psi ^{0}_{c} = \\partial_{c} \\psi. Generalization of that property for Riemannian model is performed; it is shown that in general covariant case solutions of the gradient type \\Psi^{0}_{\\beta} = (\

Red'kov, V M

2011-01-01T23:59:59.000Z

425

Squares of White Noise, SL(2,C) and Kubo - Martin -Schwinger States  

E-Print Network (OSTI)

We investigate the structure of Kubo - Martin - Schwinger (KMS) states on some extension of the universal enveloping algebra of SL(2,C}. We find that there exists a one-to-one correspondence between the set of all covariant KMS states on this algebra and the set of all probability measures d\\mu on the real half-line, which decrease faster than any inverse polynomial. This problem is connected to the problem of KMS states on square of white noise algebra.

D. V. Prokhorenko

2007-05-26T23:59:59.000Z

426

Mathematical Modeling to Study the Dynamics of A Diatomic Molecule N2 in Water  

E-Print Network (OSTI)

In the present work an attempt has been made to study the dynamics of a diatomic molecule N2 in water. The proposed model consists of Langevin stochastic differential equation whose solution is obtained through Euler's method. The proposed work has been concluded by studying the behavior of statistical parameters like variance in position, variance in velocity and covariance between position and velocity. This model incorporates the important parameters like acceleration, intermolecular force, frictional force and random force.

Sharma, Nitin

2010-01-01T23:59:59.000Z

427

Particle motion in a Yang-Mills field Wong's equations and spin one-half analogues  

E-Print Network (OSTI)

A complete, straightforward and natural Lagrangian description is given for the classical non-relativistic dynamics of a particle with colour or internal symmetry degrees of freedom moving in a background Yang-Mills field. This provides a new simple Lagrangian formalism for Wong's equations for spinless particles, and presents also their generalisation, in gauge covariant form, for spin-\\frack particles, within a complete Lagrangian formalism.

Van Holten, J W

1995-01-01T23:59:59.000Z

428

Particle Motion in a Yang-Mills Field: Wong's Equations and Spin One-half Analogues  

E-Print Network (OSTI)

A complete, straightforward and natural Lagrangian description is given for the classical non-relativistic dynamics of a particle with colour or internal symmetry degrees of freedom moving in a background Yang-Mills field. This provides a new simple Lagrangian formalism for Wong's equations for spinless particles, and presents also their generalisation, in gauge covariant form, for spin-$\\frack$ particles, within a complete Lagrangian formalism.

N Linden A J Macfarlane; J W van Holten

1995-12-11T23:59:59.000Z

429

Horizon Mechanics and Asymptotic Symmetries with a Immirzi-like Parameter in 2+1 Dimensions  

E-Print Network (OSTI)

Starting with a generalized theory of 2+1 gravity containing an Immirzi like parameter, we derive the modified laws of black hole mechanics using the formalism of weak isolated horizons. Definitions of horizon mass and angular momentum emerge naturally in this framework. We further go on to analyze the asymptotic symmetries, as first discussed by Brown and Henneaux, and analyze their implications in a completely covariant phase space framework.

Rudranil Basu; Ayan Chatterjee

2011-01-14T23:59:59.000Z

430

Lectures on loop gravity  

E-Print Network (OSTI)

This is the first version of the introductory lectures on loop quantum gravity that I will give at the quantum gravity school in Zakopane. The theory is presented in self-contained form, without emphasis on its derivation from classical general relativity. Dynamics is given in the covariant form. The approximations needed to compute physical quantities are discussed. Some applications are described, including the recent derivation of de Sitter cosmology from full quantum gravity.

Rovelli, Carlo

2011-01-01T23:59:59.000Z

431

Spin-gravity coupling and gravity-induced quantum phases  

E-Print Network (OSTI)

External gravitational fields induce phase factors in the wave functions of particles. The phases are exact to first order in the background gravitational field, are manifestly covariant and gauge invariant and provide a useful tool for the study of spin-gravity coupling and of the optics of particles in gravitational or inertial fields. We discuss the role that spin-gravity coupling plays in particular problems.

Giorgio Papini

2007-09-06T23:59:59.000Z

432

Optomechanical entanglement in the presence of laser phase noise  

SciTech Connect

We study the simplest optomechanical system in the presence of laser phase noise (LPN) using the covariance matrix formalism. We show that for any LPN model with a finite correlation time, the destructive effect of the phase noise is especially strong in the bistable regime. This explains why ground-state cooling is still possible in the presence of phase noise, as it happens far away from the bistable regime. We also show that the optomechanical entanglement is strongly affected by phase noise.

Ghobadi, R. [Institute for Quantum Information Science and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada); Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Bahrampour, A. R. [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Simon, C. [Institute for Quantum Information Science and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada)

2011-12-15T23:59:59.000Z

433

Impact of a physical activity intervention program on cognitive predictors of behaviour among adults at risk of Type 2 diabetes (ProActive randomised controlled trial)  

E-Print Network (OSTI)

probabilities to bal- ance key baseline covariates: age, living with children, behavioural intention, BMI, objective physical activity level (ratio of total energy expenditure to estimated basal meta- bolic rate) [23,26], and gender. Participants visited... interfering with the study, known pregnancy before base- line measurement, and planning to move away [19]. Measures Demographic, cognitive, behavioural and clinical measures Baseline measures included gender, age at invitation to the trial, social economic...

Hardeman, Wendy; Kinmonth, Ann Louise; Michie, Susan; Sutton, Stephen; ProActive Project Team

2009-03-17T23:59:59.000Z

434

Gravitational Energy-Momentum Density in Teleparallel Gravity  

E-Print Network (OSTI)

In the context of a gauge theory for the translation group, a conserved energy-momentum gauge current for the gravitational field is obtained. It is a true spacetime and gauge tensor, and transforms covariantly under global Lorentz transformations. By rewriting the gauge gravitational field equation in a purely spacetime form, it becomes the teleparallel equivalent of Einstein's equation, and the gauge current reduces to the M{\\o}ller's canonical energy-momentum density of the gravitational field.

V. C. de Andrade; L. C. T. Guillen; J. G. Pereira

2000-03-27T23:59:59.000Z

435

Teleparallel Spin Connection  

E-Print Network (OSTI)

A new expression for the spin connection of teleparallel gravity is proposed, given by minus the contorsion tensor plus a zero connection. The corresponding minimal coupling is covariant under local Lorentz transformation, and equivalent to the minimal coupling prescription of general relativity. With this coupling prescription, therefore, teleparallel gravity turns out to be fully equivalent to general relativity, even in the presence of spinor fields.

V. C. de Andrade; L. C. T. Guillen; J. G. Pereira

2001-04-30T23:59:59.000Z

436

Cosmology, Thermodynamics and Matter Creation  

E-Print Network (OSTI)

Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii \\cite{1} can be recovered and, at the same time their limits of validity are explicited.

J. A. S. Lima; M. O. Calvao; I. Waga

2007-08-24T23:59:59.000Z

437

Optimal team formation for software development exercise: evaluating a method for team formation based on the type of project manager  

Science Conference Proceedings (OSTI)

In the software development exercise for the third graders of the Shibaura Institute of Technology Department of Information Science and Engineering, students are assigned to each team with the capability to carry out a role, for optimization of team ... Keywords: PBL, covariance structure analysis, exercise for software development, exercises in units of groups, factor analysis, genetic algorithm, optimizing project team formation, path diagram, role assignment

Kiyomi Shirakawa; Shiori Yamamoto; Ryota Chiba; Hiroaki Hashiura; Seiichi Komiya

2010-03-01T23:59:59.000Z

438

[Completion of the dog toxicity project at the University of Utah: statistical comparison  

SciTech Connect

Radium (Ra) toxicity in dogs is a cornerstone for the evaluation of plutonium (Pu) toxicity, as it provides a possible link to Pu toxicity in humans. Survival regression models with covariates were used to estimate the risk to survival and the frequency and latency of bone tumor development. It appears for Ra that dose-rate is a more significant contributor to non-survival and bone tumors than is skeletal dose.

Bruenger, F.W.; Lloyd, R.D.

1999-12-15T23:59:59.000Z

439

Green Functions For Wave Propagation on a 5D manifold and the Associated Gauge Fields Generated by a Uniformly Moving Point Source  

E-Print Network (OSTI)

Gauge fields associated with the manifestly covariant dynamics of particles in (3,1) spacetime are five-dimensional. We provide solutions of the classical 5D gauge field equations in both (4,1) and (3,2) flat spacetime metrics for the simple example of a uniformly moving point source. Green functions for the 5D field equations are obtained, which are consistent with the solutions for uniform motion obtained directly from the field equations with free asymptotic conditions.

I. Aharonovich; L. P. Horwitz

2006-03-30T23:59:59.000Z

440

Green's Function expansion of scalar and vector fields in the presence of a medium  

E-Print Network (OSTI)

Based on a canonical approach and functional-integration techniques, a series expansion of Green's function of a scalar field, in the presence of a medium, is obtained. A series expansion for Lifshitz-energy, in finite-temperature, in terms of the susceptibility of the medium is derived and the whole formalism is generalized to the case of electromagnetic field in the presence of some dielectrics. A covariant formulation of the problem is presented.

Fardin Kheirandish; Shahriar Salimi

2010-10-17T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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

Is there an Ay problem in low-energy neutron-proton scattering?  

E-Print Network (OSTI)

We calculate Ay in neutron-proton scattering for the interactions models WJC-1 and WJC-2 in the Covariant Spectator Theory. We find that the recent 12 MeV measurements performed at TUNL are in better agreement with our results than with the Nijmegen Phase Shift Analysis of 1993, and after reviewing the low-energy data, conclude that there is no Ay problem in low-energy np scattering.

Gross, Franz

2008-01-01T23:59:59.000Z

442

Is there an Ay problem in low-energy neutron-proton scattering?  

E-Print Network (OSTI)

We calculate Ay in neutron-proton scattering for the interactions models WJC-1 and WJC-2 in the Covariant Spectator Theory. We find that the recent 12 MeV measurements performed at TUNL are in better agreement with our results than with the Nijmegen Phase Shift Analysis of 1993, and after reviewing the low-energy data, conclude that there is no Ay problem in low-energy np scattering.

Franz Gross; Alfred Stadler

2008-08-21T23:59:59.000Z

443

Spinor wave equation of photon  

E-Print Network (OSTI)

In this paper, we give the spinor wave equations of free and unfree photon, which are the differential equation of space-time one order. For the free photon, the spinor wave equations are covariant, and the spinors $\\psi$ are corresponding to the the reducibility representations $D^{10}+D^{01}$ and $D^{10}+D^{01}+D^{1/2 1/2}$ of the proper Lorentz group.

Xiang-Yao Wu; Bo-Jun Zhang; Xiao-Jing Liu; Si-Qi Zhang; Jing Wang; Hong Li; Xi-Hui Fan; Jing-Wu Li

2012-12-14T23:59:59.000Z

444

On the growth of perturbations in interacting dark energy and dark matter fluids  

E-Print Network (OSTI)

The covariant generalizations of the background dark sector coupling suggested in G. Mangano, G. Miele and V. Pettorino, Mod. Phys. Lett. A 18, 831 (2003) are considered. The evolution of perturbations is studied with detailed attention to interaction rate that is proportional to the product of dark matter and dark energy densities. It is shown that some classes of models with coupling of this type do not suffer from early time instabilities in strong coupling regime.

N. A. Koshelev

2009-12-01T23:59:59.000Z

445

Neutron-Induced Cross Sections Measurements of Calcium  

Science Conference Proceedings (OSTI)

To support the US Department of Energy Nuclear Criticality Safety Program neutron induced cross section experiments were performed at the Geel Electron Linear Accelerator of the Institute for Reference Material and Measurements of the Joint Research Centers, European Union. Neutron capture and transmission measurements were carried out using a metallic calcium sample. The obtained data will be used for a new calcium evaluation, which will be submitted with its covariances to the ENDBF/B nuclear data base.

Guber, Klaus H [ORNL; Kopecky, S. [EC-JRC-IRMM, Geel, Belgium; Schillebeeckx, P. [EC-JRC-IRMM, Geel, Belgium; Kauwenberghs, K. [EC-JRC-IRMM, Geel, Belgium; Siegler, P. [EC-JRC-IRMM, Geel, Belgium

2013-01-01T23:59:59.000Z

446

Characterization of quantum angular-momentum fluctuations via principal components  

E-Print Network (OSTI)

We elaborate an approach to quantum fluctuations of angular momentum based on the diagonalization of the covariance matrix in two versions: real symmetric and complex Hermitian. At difference with previous approaches this is SU(2) invariant and avoids any difficulty caused by nontrivial commutators. Meaningful uncertainty relations are derived which are nontrivial even for vanishing mean angular momentum. We apply this approach to some relevant states.

Ángel Rivas; Alfredo Luis

2007-10-25T23:59:59.000Z

447

Path forward for dosimetry cross sections  

SciTech Connect

In the 1980's the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of 'due consideration' of experimental data in the evaluation. (authors)

Griffin, P.J. [Sandia National Laboratories, Albuquerque, NM 87185-1146 (United States); Peters, C.D. [Sandia Staffing Alliance, Albuquerque, NM 87110 (United States)

2011-07-01T23:59:59.000Z

448

A hybrid CMA-ES and HDE optimisation algorithm with application to solar energy potential  

Science Conference Proceedings (OSTI)

This paper describes the results of initial experiments to apply computational algorithms to explore a large parameter space containing many variables in the search for an optimal solution for the sustainable design of an urban development using a potentially ... Keywords: Covariance matrix adaptation evolution strategy (CMA-ES), Differential evolution (DE), Hybrid CMA-ES/HDE, Hybrid differential evolution (HDE), Hybrid evolutionary algorithm, Optimisation, Solar energy potential, Urban planning

Jérôme Henri Kämpf; Darren Robinson

2009-03-01T23:59:59.000Z

449

Born-Jordan Quantization and the Uncertainty Principle  

E-Print Network (OSTI)

The Weyl correspondence and the related Wigner formalism lie at the core of traditional quantum mechanics. We discuss here an alternative quantization scheme, whose idea goes back to Born and Jordan, and which has recently been revived in another context, namely time-frequency analysis. We show that in particular the uncertainty principle does not enjoy full symplectic covariance properties in the Born and Jordan scheme, as opposed to what happens in the Weyl quantization.

Maurice A. de Gosson

2013-03-11T23:59:59.000Z

450

Statistical issues in Mendelian randomization: use of genetic instrumental variables for assessing causal associations  

E-Print Network (OSTI)

); covariate for Y (Chapters 4 and 6) G instrumental variable ? parameter of genetic association: regression parameter in the G-X re- gression ? regression parameter in the X-Y regression ?1 causal effect of X on Y : the main parameter of interest ? parameter... of genetic association for haplotypes: regression parameter in the G-X regression where G represents a haplotype or diplotype ? correlation parameter ?2 variance parameter ? 2 between-study heterogeneity variance parameter ?2 genetic between...

Burgess, Stephen

2012-03-06T23:59:59.000Z

451

Quantum stochastic processes for maps on Hilbert C*-modules  

SciTech Connect

We discuss pairs ({phi}, {Phi}) of maps, where {phi} is a map between C*-algebras and {Phi} is a {phi}-module map between Hilbert C*-modules, which are generalization of representations of Hilbert C*-modules. A covariant version of Stinespring's theorem for such a pair ({phi}, {Phi}) is established, and quantum stochastic processes constructed from pairs ({l_brace}{phi}{sub t{r_brace}}, {l_brace}{Phi}{sub t{r_brace}}) of families of such maps are studied. We prove that the quantum stochastic process J={l_brace}J{sub t{r_brace}} constructed from a {phi}-quantum dynamical semigroup {Phi}={l_brace}{Phi}{sub t{r_brace}} is a j-map for the quantum stochastic process j={l_brace}j{sub t{r_brace}} constructed from the given quantum dynamical semigroup {phi}={l_brace}{phi}{sub t{r_brace}}, and that J is covariant if the {phi}-quantum dynamical semigroup {Phi} is covariant.

Heo, Jaeseong [Department of Mathematics, Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Ji, Un Cig [Department of Mathematics, Research Institute of Mathematical Finance, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

2011-05-15T23:59:59.000Z

452

A C*-algebra for quantized principal U(1)-connections on globally hyperbolic Lorentzian manifolds  

E-Print Network (OSTI)

The aim of this work is to complete our program on the quantization of connections on arbitrary principal U(1)-bundles over globally hyperbolic Lorentzian manifolds. In particular, we show that one can assign via a covariant functor to any such bundle an algebra of observables which separates gauge equivalence classes of connections. The C*-algebra we construct generalizes the usual CCR-algebras since, contrary to the standard field-theoretic models, it is based on a presymplectic Abelian group instead of a symplectic vector space. We prove a no-go theorem according to which neither this functor, nor any of its quotients, satisfy the strict axioms of general local covariance. Yet, if we fix any principal U(1)-bundle, there exists a suitable category of sub-bundles for which a quotient of our functor yields a quantum field theory in the sense of Haag and Kastler. We shall provide a physical interpretation of this feature and we obtain some new insights concerning electric charges in locally covariant quantum field theory.

Marco Benini; Claudio Dappiaggi; Thomas-Paul Hack; Alexander Schenkel

2013-07-11T23:59:59.000Z

453

Feynman's Branes and Feynman's Oscillators  

E-Print Network (OSTI)

Based on Feynman's lifetime efforts on quantum mechanics and relativity, it is concluded that the basic difference between field theory and string theory is that field theory is based on running waves while string theory should deal with standing waves in the Lorentz-covariant regime. At the 1970 spring meeting of the American Physical Society held in Washington, DC, R. P. Feynman stunned the audience by proposing harmonic oscillators for relativistic bound states, instead of Feynman diagrams. His talk was later published in the paper of Feynman, Kislinger, and Ravndal [Phys. Rev. D, Vol. 3, 2706 (1971)]. These authors noted that the hadron mass spectra can be predicted by the degeneracy of the three-dimensional harmonic oscillators. In so doing, they started with the Lorentz-invariant differential equation for the harmonic oscillator, and obtained Lorentz invariant solutions. However, their solutions are not normalizable in the time-separation variable and cannot carry probability interpretation. It is pointed out that there are solutions normalizable in the time-separation variable within the framework of Wigner's little-group representation of the Poincar\\'e group. These solutions are not invariant but covariant under Lorentz transformations. These solutions give a covariant bound-state model which gives the quark model and the parton model as two different limiting cases, in the low- and high-speed limits respectively.

Y. S. Kim; Marilyn E. Noz

2004-02-19T23:59:59.000Z

454

Ocean heat transport in a Simple Ocean Data Assimilation (SODA): structure, mechanisms, and impacts on climate  

E-Print Network (OSTI)

level, the standard error of the intercept is underestimated whereas the standard error of the regression coefficients associated with the covariate of the intermediate level and the remaining crossed factor are overestimated. When the ignored crossed factor is at the intermediate level, only the standard error of the regression coefficients associated with the covariate of the bottom level is overestimated. In Study Two, longitudinal multilevel data were generated mirroring studies in which students are measured repeatedly and change schools over time. It was found that when the school level is modeled hierarchically above the student level rather than as a crossed factor, part of the variance at the school level is added to the student level, causing underestimation of the school-level variance and overestimation of the studentlevel variance and covariance. The standard errors of the intercept and the regression coefficients associated with the school-level predictors are underestimated, which may cause spurious significance for results. The findings of the dissertation enhanced our understanding of the functioning of CCREMs in both cross-sectional and longitudinal multilevel data. The findings can help researchers to determine when CCREMs should be used and to interpret their results with caution when they misspecify CCREMs.

Zheng, Yangxing

2007-08-01T23:59:59.000Z

455

CROSS SECTION EVALUATIONS FOR ENDF/B-VII.  

SciTech Connect

This is the final report of the work performed under the LANL contract on neutron cross section evaluations for ENDF/B-VII (April 2005-May 2006). The purpose of the contract was to ensure seamless integration of the LANL neutron cross section evaluations in the new ENDF/B-VII library. The following work was performed: (1) LANL evaluated data files submitted for inclusion in ENDF/B-VII were checked and, when necessary, formal formatting errors were corrected. As a consequence, ENDF checking codes, run on all LANL files, do not report any errors that would rise concern. (2) LANL dosimetry evaluations for {sup 191}Ir and {sup 193}Ir were completed to match ENDF requirements for the general purpose library suitable for transport calculations. A set of covariances for both isotopes is included in the ENDF files. (3) Library of fission products was assembled and successfully tested with ENDF checking codes, processed with NJOY-99.125 and simple MCNP calculations. (4) KALMAN code has been integrated with the EMPIRE system to allow estimation of covariances based on the combination of measurements and model calculations. Covariances were produced for 155,157-Gd and also for 6 remaining isotopes of Gd.

HERMAN, M.; ROCHMAN, D.; OBLOZINSKY, P.

2006-06-05T23:59:59.000Z

456

A Generalized Adjoint Approach for Quantifying Reflector Assembly Discontinuity Factor Uncertainties  

SciTech Connect

Sensitivity-based uncertainty analysis of assembly discontinuity factors (ADFs) can be readily performed using adjoint methods for infinite lattice models. However, there is currently no adjoint-based methodology to obtain uncertainties for ADFs along an interface between a fuel and reflector region. To accommodate leakage effects in a reflector region, a 1D approximation is usually made in order to obtain the homogeneous interface flux required to calculate the ADF. Within this 1D framework an adjoint-based method is proposed that is capable of efficiently calculating ADF uncertainties. In the proposed method the sandwich rule is utilized to relate the covariance of the input parameters of 1D diffusion theory in the reflector region to the covariance of the interface ADFs. The input parameters covariance matrix can be readily obtained using sampling-based codes such as XSUSA or adjoint-based codes such as TSUNAMI. The sensitivity matrix is constructed using a fixed-source adjoint approach for inputs characterizing the reflector region. An analytic approach is then used to determine the sensitivity of the ADFs to fuel parameters using the neutron balance equation. A stochastic approach is used to validate the proposed adjoint-based method.

Yankov, Artem [University of Michigan; Collins, Benjamin [University of Michigan; Jessee, Matthew Anderson [ORNL; Downar, Thomas [University of Michigan

2012-01-01T23:59:59.000Z

457

Application of Bayesian Hierarchical Models in Genetic Data Analysis  

E-Print Network (OSTI)

Genetic data analysis has been capturing a lot of attentions for understanding the mechanism of the development and progressing of diseases like cancers, and is crucial in discovering genetic markers and treatment targets in medical research. This dissertation focuses on several important issues in genetic data analysis, graphical network modeling, feature selection, and covariance estimation. First, we develop a gene network modeling method for discrete gene expression data, produced by technologies such as serial analysis of gene expression and RNA sequencing experiment, which generate counts of mRNA transcripts in cell samples. We propose a generalized linear model to fit the discrete gene expression data and assume that the log ratios of the mean expression levels follow a Gaussian distribution. We derive the gene network structures by selecting covariance matrices of the Gaussian distribution with a hyper-inverse Wishart prior. We incorporate prior network models based on Gene Ontology information, which avails existing biological information on the genes of interest. Next, we consider a variable selection problem, where the variables have natural grouping structures, with application to analysis of chromosomal copy number data. The chromosomal copy number data are produced by molecular inversion probes experiments which measure probe-specific copy number changes. We propose a novel Bayesian variable selection method, the hierarchical structured variable se- lection (HSVS) method, which accounts for the natural gene and probe-within-gene architecture to identify important genes and probes associated with clinically relevant outcomes. We propose the HSVS model for grouped variable selection, where simultaneous selection of both groups and within-group variables is of interest. The HSVS model utilizes a discrete mixture prior distribution for group selection and group-specific Bayesian lasso hierarchies for variable selection within groups. We further provide methods for accounting for serial correlations within groups that incorporate Bayesian fused lasso methods for within-group selection. Finally, we propose a Bayesian method of estimating high-dimensional covariance matrices that can be decomposed into a low rank and sparse component. This covariance structure has a wide range of applications including factor analytical model and random effects model. We model the covariance matrices with the decomposition structure by representing the covariance model in the form of a factor analytic model where the number of latent factors is unknown. We introduce binary indicators for estimating the rank of the low rank component combined with a Bayesian graphical lasso method for estimating the sparse component. We further extend our method to a graphical factor analytic model where the graphical model of the residuals is of interest. We achieve sparse estimation of the inverse covariance of the residuals in the graphical factor model by employing a hyper-inverse Wishart prior method for a decomposable graph and a Bayesian graphical lasso method for an unrestricted graph.

Zhang, Lin

2012-12-01T23:59:59.000Z

458

Rapid Calibration of High Resolution Geologic Models to Dynamic Data Using Inverse Modeling: Field Application and Validation  

Science Conference Proceedings (OSTI)

Streamline-based assisted and automatic history matching techniques have shown great potential in reconciling high resolution geologic models to production data. However, a major drawback of these approaches has been incompressibility or slight compressibility assumptions that have limited applications to two-phase water-oil displacements only. We propose an approach to history matching three-phase flow using a novel compressible streamline formulation and streamline-derived analytic sensitivities. First, we utilize a generalized streamline model to account for compressible flow by introducing an 'effective density' of total fluids along streamlines. Second, we analytically compute parameter sensitivities that define the relationship between the reservoir properties and the production response, viz. water-cut and gas/oil ratio (GOR). These sensitivities are an integral part of history matching, and streamline models permit efficient computation of these sensitivities through a single flow simulation. We calibrate geologic models to production data by matching the water-cut and gas/oil ratio using our previously proposed generalized travel time inversion (GTTI) technique. For field applications, however, the highly non-monotonic profile of the gas/oil ratio data often presents a challenge to this technique. In this work we present a transformation of the field production data that makes it more amenable to GTTI. Further, we generalize the approach to incorporate bottom-hole flowing pressure during three-phase history matching. We examine the practical feasibility of the method using a field-scale synthetic example (SPE-9 comparative study) and a field application. Recently Ensemble Kalman Filtering (EnKF) has gained increased attention for history matching and continuous reservoir model updating using data from permanent downhole sensors. It is a sequential Monte-Carlo approach that works with an ensemble of reservoir models. Specifically, the method utilizes cross-covariances between measurements and model parameters estimated from the ensemble. For practical field applications, the ensemble size needs to be kept small for computational efficiency. However, this leads to poor approximations of the cross-covariance matrix, resulting in loss of geologic realism. Specifically, the updated parameter field tends to become scattered with a loss of connectivities of extreme values such as high permeability channels and low permeability barriers, which are of special significance during reservoir characterization. We propose a novel approach to overcome this limitation of the EnKF through a 'covariance localization' method that utilizes sensitivities that quantify the influence of model parameters on the observed data. These sensitivities are used in the EnKF to modify the cross-covariance matrix in order to reduce unwanted influences of distant observation points on model parameter updates. The key to the success of the sensitivity-based covariance-localization is its close link to the underlying physics of flow compared to a simple distance-dependent covariance function as used in the past. This flow-relevant conditioning leads to an efficient and robust approach for history matching and continuous reservoir model updating, avoiding much of the problems in traditional EnKF associated with instabilities, parameter overshoots and loss of geologic continuity. We illustrate the power and utility of our approach using both synthetic and field applications.

Akhil Datta-Gupta

2008-03-31T23:59:59.000Z

459

Relationship between blood manganese and blood pressure in the Korean general population according to KNHANES 2008  

SciTech Connect

Introduction: We present data on the association of manganese (Mn) level with hypertension in a representative sample of the adult Korean population who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) 2008. Methods: This study was based on the data obtained by KNHANES 2008, which was conducted for three years (2007-2009) using a rolling sampling design involving a complex, stratified, multistage, probability-cluster survey of a representative sample of the noninstitutionalized civilian population of South Korea. Results: Multiple regression analysis after controlling for covariates, including gender, age, regional area, education level, smoking, drinking status, hemoglobin, and serum creatinine, showed that the beta coefficients of log blood Mn were 3.514, 1.878, and 2.517 for diastolic blood pressure, and 3.593, 2.449, and 2.440 for systolic blood pressure in female, male, and all participants, respectively. Multiple regression analysis including three other blood metals, lead, mercury, and cadmium, revealed no significant effects of the three metals on blood pressure and showed no effect on the association between blood Mn and blood pressure. In addition, doubling the blood Mn increased the risk of hypertension 1.828, 1.573, and 1.567 fold in women, men, and all participants, respectively, after adjustment for covariates. The addition of blood lead, mercury, and cadmium as covariates did not affect the association between blood Mn and the prevalence of hypertension. Conclusion: Blood Mn level was associated with an increased risk of hypertension in a representative sample of the Korean adult population. - Highlights: {yields} We showed the association of manganese with hypertension in Korean population. {yields} This study was based on the data obtained by KNHANES 2008. {yields} Blood manganese level was associated with an increased risk of hypertension.

Lee, Byung-Kook [Institute of Environmental and Occupational Medicine, Soonchunhyang University 646 Eupnae-ri, Shinchang-myun, Asan-si, Choongnam 336-745 (Korea, Republic of)] [Institute of Environmental and Occupational Medicine, Soonchunhyang University 646 Eupnae-ri, Shinchang-myun, Asan-si, Choongnam 336-745 (Korea, Republic of); Kim, Yangho, E-mail: yanghokm@nuri.net [Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, 290-3 Cheonha-Dong, Dong-Gu, Ulsan 682-060 (Korea, Republic of)] [Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, 290-3 Cheonha-Dong, Dong-Gu, Ulsan 682-060 (Korea, Republic of)

2011-08-15T23:59:59.000Z

460

Nuclear data uncertainty analysis for the generation IV gas-cooled fast reactor  

Science Conference Proceedings (OSTI)

For the European 2400 MW Gas-cooled Fast Reactor (GoFastR), this paper summarizes a priori uncertainties, i.e. without any integral experiment assessment, of the main neutronic parameters which were obtained on the basis of the deterministic code system ERANOS (Edition 2.2-N). JEFF-3.1 cross-sections were used in conjunction with the newest ENDF/B-VII.0 based covariance library (COMMARA-2.0) resulting from a recent cooperation of the Brookhaven and Los Alamos National Laboratories within the Advanced Fuel Cycle Initiative. The basis for the analysis is the original GoFastR concept with carbide fuel pins and silicon-carbide ceramic cladding, which was developed and proposed in the first quarter of 2009 by the 'French alternative energies and Atomic Energy Commission', CEA. The main conclusions from the current study are that nuclear data uncertainties of neutronic parameters may still be too large for this Generation IV reactor, especially concerning the multiplication factor, despite the fact that the new covariance library is quite complete; These uncertainties, in relative terms, do not show the a priori expected increase with bum-up as a result of the minor actinide and fission product build-up. Indeed, they are found almost independent of the fuel depletion, since the uncertainty associated with {sup 238}U inelastic scattering results largely dominating. This finding clearly supports the activities of Subgroup 33 of the Working Party on International Nuclear Data Evaluation Cooperation (WPEC), i.e. Methods and issues for the combined use of integral experiments and covariance data, attempting to reduce the present unbiased uncertainties on nuclear data through adjustments based on available experimental data. (authors)

Pelloni, S.; Mikityuk, K. [Paul Scherrer Inst., 5232 Villigen PSI (Switzerland)

2012-07-01T23:59:59.000Z

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461

Parity-based formalism for high spin matter fields  

E-Print Network (OSTI)

Using the recent parity-based construction of a covariant basis for operators acting on the $(j,0)\\oplus(0,j)$ representation of the HLG, we propose a formalism for the description of high spin matter fields, based on the projection over subspaces of well-defined parity. We identify two possibilities for the projection, on-shell and off-shell projection. For all $j$ except for $j=1/2$, we find that the projection does not completely fix the properties of the interacting theory. This freedom is related to the fact that the covariant form of parity can be written in terms of one of the symmetric traceless tensors in the covariant basis and in general allows for a free magnetic dipole term in the lagrangian. We gauge the theory and construct the charge conjugation operator. In the case of bosons, the parity invariant subspaces are also invariant under charge conjugation and time reversal and the formulation of a quantum field theory can be done using only these subspaces. As a first exhaustive example we work out the electrodynamics for $j=1$ matter bosons, rewrite the theory in terms of an antisymmetric tensor field and compare our results with existing formalisms in the literature. We find that there are three essentially different formalisms: i) formalisms equivalent to the on-shell parity projection, ii) formalisms equivalent to the off-shell parity projection and iii) the Poincar\\'e projector formalism which describes a degenerate parity doublet. We perform a chiral decomposition of these theories and show that chiral symmetry can be realized linearly only for the theory based on the on-shell projection. Chiral symmetry forbids mass and anomalous magnetic dipole terms and in general admits six self-interaction terms. We conclude that this is the appropriate framework to attempt the incorporation of spin 1 matter bosons in chiral theories like the standard model.

M. Napsuciale; Selim Gómez-Ávila

2013-09-04T23:59:59.000Z

462

Cloning of arbitrary mirror-symmetric distributions on Bloch sphere: Optimality proof and proposal for practical photonic realization  

E-Print Network (OSTI)

We study state-dependent quantum cloning which can outperform universal cloning. This is possible by using some a priori information on a given quantum state to be cloned. Specifically, we propose a generalization and optical implementation of quantum optimal mirror phase-covariant cloning, which refers to optimal cloning of sets of qubits of known modulus of expectation value of Pauli's Z operator. Our results can be applied for cloning of an arbitrary mirror-symmetric distribution of qubits on Bloch sphere including in special cases the universal cloning and phase-covariant cloning. We show that the cloning is optimal by adapting our former optimality proof for axisymmetric cloning [Phys. Rev. 82, 042330 (2010)]. Moreover, we propose an optical realization of the optimal mirror phase-covariant 1 to 2 cloning of a qubit, for which the mean probability of successful cloning varies from 1/6 to 1/3 depending on prior information on the set of qubits to be cloned. The qubits are represented by polarization states of photons generated by the type-I spontaneous parametric down-conversion. The scheme is based on the interference of two photons on an unbalanced polarization-dependent beam splitter with different splitting ratios for vertical and horizontal polarization components and the additional application of feedforward by means of Pockels cells. The experimental feasibility of the proposed setup is carefully studied including various kinds of imperfections and losses including: (i) finite efficiency of generating a pair of entangled photons in the type-I spontaneous parametric down conversion, (ii) the influence of choosing various splitting ratios of the unbalanced beam splitter, (iii) the application of conventional and single-photon discriminating detectors, (iv) dark counts and finite efficiency of the detectors.

Karol Bartkiewicz; Adam Miranowicz

2011-03-28T23:59:59.000Z

463

Tidal indicators in the spacetime of a rotating deformed mass  

E-Print Network (OSTI)

Tidal indicators are commonly associated with the electric and magnetic parts of the Riemann tensor (and its covariant derivatives) with respect to a given family of observers in a given spacetime. Recently, observer-dependent tidal effects have been extensively investigated with respect to a variety of special observers in the equatorial plane of the Kerr spacetime. This analysis is extended here by considering a more general background solution to include the case of matter which is also endowed with an arbitrary mass quadrupole moment. Relation with curvature invariants and Bel-Robinson tensor, i.e., observer-dependent super-energy density and super-Poynting vector, are investigated too.

Donato Bini; Kuantay Boshkayev; Andrea Geralico

2013-06-20T23:59:59.000Z

464

Covaraint energy-momentum and an uncertainty principle for general relativity  

E-Print Network (OSTI)

We recognize the natural covariant extension for energy-momentum in general relativity: energy-momentum in spacetime as opposed to space. The key indicator is the Tolman energy integral for stationary systems. The demand that the general expression for arbitrary dynamic systems reduce to the Tolman integral in the case of stationarity leads to the matter-localized Ricci integral for energy-momentum in support of the energy localization hypothesis. It is suggested that in the extreme of strong gravity, the Heisenberg Uncertainty Principle be generalized in terms of spacetime energy-momentum.

Cooperstock, F I

2009-01-01T23:59:59.000Z

465

On the relation between the Einstein field equations and the Jacobi-Ricci-Bianchi system  

E-Print Network (OSTI)

The 1+3 covariant equations, embedded in an extended tetrad formalism and describing a space-time with an arbitrary energy-momentum distribution, are reconsidered. It is shown that, provided the 1+3 splitting is performed with respect to a generic timelike congruence with tangent vector u, the Einstein field equations can be regarded as the integrability conditions for the Jacobi and Bianchi equations together with the Ricci equations for u. The same conclusion holds for a generic null congruence in the Newman-Penrose framework.

Norbert Van den Bergh

2013-02-26T23:59:59.000Z

466

Yang-Mills Gauge Conditions from Witten's Open String Field Theory  

E-Print Network (OSTI)

We construct the Zinn-Justin-Batalin-Vilkovisky action for tachyons and gauge bosons from Witten's 3-string vertex of the bosonic open string without gauge fixing. Through canonical transformations, we find the off-shell, local, gauge-covariant action up to 3-point terms, satisfying the usual field theory gauge transformations. Perturbatively, it can be extended to higher-point terms. It also gives a new gauge condition in field theory which corresponds to the Feynman-Siegel gauge on the world-sheet.

Haidong Feng; Warren Siegel

2006-11-28T23:59:59.000Z

467

Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation  

E-Print Network (OSTI)

This dissertation examines the performance of an ensemble Kalman filter (EnKF) implemented in a mesoscale model in increasingly realistic contexts from under a perfect model assumption and in the presence of significant model error with synthetic observations to real-world data assimilation in comparison to the three-dimensional variational (3DVar) method via both case study and month-long experiments. The EnKF is shown to be promising for future application in operational data assimilation practice. The EnKF with synthetic observations, which is implemented in the mesoscale model MM5, is very effective in keeping the analysis close to the truth under the perfect model assumption. The EnKF is most effective in reducing larger-scale errors but less effective in reducing errors at smaller, marginally resolvable scales. In the presence of significant model errors from physical parameterization schemes, the EnKF performs reasonably well though sometimes it can be significantly degraded compared to its performance under the perfect model assumption. Using a combination of different physical parameterization schemes in the ensemble (the so-called �multi-scheme� ensemble) can significantly improve filter performance due to the resulting better background error covariance and a smaller ensemble bias. The EnKF performs differently for different flow regimes possibly due to scale- and flow-dependent error growth dynamics and predictability. Real-data (including soundings, profilers and surface observations) are assimilated by directly comparing the EnKF and 3DVar and both are implemented in the Weather Research and Forecasting model. A case study and month-long experiments show that the EnKF is efficient in tracking observations in terms of both prior forecast and posterior analysis. The EnKF performs consistently better than 3DVar for the time period of interest due to the benefit of the EnKF from both using ensemble mean for state estimation and using a flow-dependent background error covariance. Proper covariance inflation and using a multi-scheme ensemble can significantly improve the EnKF performance. Using a multi-scheme ensemble results in larger improvement in thermodynamic variables than in other variables. The 3DVar system can benefit substantially from using a short-term ensemble mean for state estimate. Noticeable improvement is also achieved in 3DVar by including some flow dependence in its background error covariance.

Meng, Zhiyong

2003-05-01T23:59:59.000Z

468

Fractional oscillator process with two indices  

E-Print Network (OSTI)

We introduce a new fractional oscillator process which can be obtained as solution of a stochastic differential equation with two fractional orders. Basic properties such as fractal dimension and short range dependence of the process are studied by considering the asymptotic properties of its covariance function. The fluctuation--dissipation relation of the process is investigated. The fractional oscillator process can be regarded as one-dimensional fractional Euclidean Klein-Gordon field, which can be obtained by applying the Parisi-Wu stochastic quantization method to a nonlocal Euclidean action. The Casimir energy associated with the fractional field at positive temperature is calculated by using the zeta function regularization technique.

S. C. Lim; L. P. Teo

2008-04-24T23:59:59.000Z

469

Note on tachyon moduli and closed strings  

SciTech Connect

The collective behavior of the SL(2,R) covariant brane states of noncritical c=1 string theory, found in a previous work, is studied in the Fermi liquid approximation. It is found that such states mimic the coset WZW model, whereas only by further restrictions one recovers the double-scaling limit which was purported to be equivalent to closed string models. Another limit is proposed, inspired by the tachyon condensation ideas, where the spectrum is the same of two-dimensional string theory. We close by noting some strange connections between vacuum states of the theory in their different interpretations.

Carneiro da Cunha, Bruno [Helsinki Institute of Physics, P.O. Box 64, FIN-00014 University of Helsinki (Finland) and Departamento de Fisica, Universidade Federal de Pernambuco, CEP 53901-970, Recife, Pernambuco (Brazil)

2008-07-15T23:59:59.000Z

470

On precanonical quantization of gravity in spin connection variables  

SciTech Connect

The basics of precanonical quantization and its relation to the functional Schroedinger picture in QFT are briefly outlined. The approach is then applied to quantization of Einstein's gravity in vielbein and spin connection variables and leads to a quantum dynamics described by the covariant Schroedinger equation for the transition amplitudes on the bundle of spin connection coefficients over space-time, that yields a novel quantum description of space-time geometry. A toy model of precanonical quantum cosmology based on the example of flat FLRW universe is considered.

Kanatchikov, I. V. [National Center of Quantum Information in Gdansk (KCIK), 81-824 Sopot (Poland)

2013-02-21T23:59:59.000Z

471

Consistent matter couplings for Plebanski gravity  

SciTech Connect

We develop a scheme for the minimal coupling of all standard types of tensor and spinor field matter to Plebanski gravity. This theory is a geometric reformulation of vacuum general relativity in terms of two-form frames and connection one-forms, and provides a covariant basis for various quantization approaches. Using the spinor formalism we prove the consistency of the newly proposed matter coupling by demonstrating the full equivalence of Plebanski gravity plus matter to Einstein-Cartan gravity. As a by-product we also show the consistency of some previous suggestions for matter actions.

Tennie, Felix; Wohlfarth, Mattias N. R. [Zentrum fuer Mathematische Physik und II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

2010-11-15T23:59:59.000Z

472

Massive Type II in Double Field Theory  

E-Print Network (OSTI)

We provide an extension of the recently constructed double field theory formulation of the low-energy limits of type II strings, in which the RR fields can depend simultaneously on the 10-dimensional space-time coordinates and linearly on the dual winding coordinates. For the special case that only the RR one-form of type IIA carries such a dependence, we obtain the massive deformation of type IIA supergravity due to Romans. For T-dual configurations we obtain a `massive' but non-covariant formulation of type IIB, in which the 10-dimensional diffeomorphism symmetry is deformed by the mass parameter.

Olaf Hohm; Seung Ki Kwak

2011-08-24T23:59:59.000Z

473

Combining Quark and Link Smearing to Improve Extended Baryon Operators  

SciTech Connect

The effects of Gaussian quark-field smearing and analytic stout-link smearing on the correlations of gauge-invariant extended baryon operators are studied. Gaussian quark-field smearing substantially reduces contributions from the short wavelength modes of the theory, while stout-link smearing significantly reduces the noise from the stochastic evaluations. The use of gauge-link smearing is shown to be crucial for baryon operators constructed of covariantly-displaced quark fields. Preferred smearing parameters are determined for a lattice spacing a_s ~ 0.1 fm.

Adam Lichtl; Subhasish Basak; Robert Edwards; George T. Fleming; Urs M. Heller; Colin Morningstar; David Richards; Ikuro Sato; Stephen Wallace

2005-09-29T23:59:59.000Z

474

Quantum field theory in the presence of a medium: Green's function expansions  

SciTech Connect

Starting from a Lagrangian and using functional-integration techniques, series expansions of Green's function of a real scalar field and electromagnetic field, in the presence of a medium, are obtained. The parameter of expansion in these series is the susceptibility function of the medium. Relativistic and nonrelativistic Langevin-type equations are derived. Series expansions for Lifshitz energy in finite temperature and for an arbitrary matter distribution are derived. Covariant formulations for both scalar and electromagnetic fields are introduced. Two illustrative examples are given.

Kheirandish, Fardin [Department of Physics, Islamic Azad University, Shahreza-Branch, Shahreza (Iran, Islamic Republic of); Salimi, Shahriar [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2011-12-15T23:59:59.000Z

475

Optimization of Biogas Production with Computational Intelligence A Comparative Study ?  

E-Print Network (OSTI)

Biogas plants are reliable sources of energy based on renewable materials including organic waste. There is a high demand from industry to run these plants efficiently, which leads to a highly complex simulation and optimization problem. A comparison of several algorithms from computational intelligence to solve this problem is presented in this study. The sequential parameter optimization was used to determine improved parameter settings for these algorithms in an automated manner. We demonstrate that genetic algorithm and particle swarm optimization based approaches were outperformed by differential evolution and covariance matrix adaptation evolution strategy. Compared to previously presented results, our approach required only one tenth of the number of function evaluations. 1

Jörg Ziegenhirt; Thomas Bartz-beielstein; Oliver Flasch; Wolfgang Konen; Martin Zaefferer

2010-01-01T23:59:59.000Z

476

Teleparallel Gravity and the Gravitational Energy-Momentum Density  

E-Print Network (OSTI)

In the context of the teleparallel equivalent of general relativity, we show that the energy-momentum density for the gravitational field can be described by a true spacetime tensor. It is also invariant under local (gauge) translations of the tangent space coordinates, but transforms covariantly only under global Lorentz transformations. When the gauge gravitational field equation is written in a purely spacetime form, it becomes the teleparallel equivalent of Einstein's equation, and we recover M{\\o}ller's expression for the canonical gravitational energy-momentum pseudotensor.

V. C. de Andrade; L. C. T. Guillen; J. G. Pereira

2000-11-22T23:59:59.000Z

477

Eddy Correlation Flux Measurement System (ECOR) Handbook  

SciTech Connect

The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.

Cook, DR

2011-01-31T23:59:59.000Z

478

Non-linear hydrodynamics of incommensurate intergrowth compounds and quasicrystals  

E-Print Network (OSTI)

Hamiltonian structures for non-linear hydrodynamics of incommensurate intergrowth compounds (IIC) and quasicrystals (IQ) are constructed. We discuss also the way to account for internal friction of phason nature. We show that the existence of a self-force in IIC and IQ is not only matter of constitutive issues, rather it is related with questions of SO(3) invariance. The covariant mechanics of discontinuity surfaces in quasiperiodic structures is also analyzed. The attention is mainly focused on the interaction between `diffuse' grain boundaries and sharp discontinuity (moving possibly) surfaces.

Paolo Maria Mariano

2004-07-16T23:59:59.000Z

479

Generalized Lorentz-Dirac Equation for a Strongly Coupled Gauge Theory  

SciTech Connect

We derive a semiclassical equation of motion for a 'composite' quark in strongly coupled large-N{sub c} N=4 super Yang-Mills theory, making use of the anti-de Sitter space/conformal field theory correspondence. The resulting nonlinear equation incorporates radiation damping, and reduces to the standard Lorentz-Dirac equation for external forces that are small on the scale of the quark Compton wavelength, but has no self-accelerating or preaccelerating solutions. From this equation one can read off a nonstandard dispersion relation for the quark, as well as a Lorentz-covariant formula for its radiation rate.

Chernicoff, Mariano; Garcia, J. Antonio; Gueijosa, Alberto [Departamento de Fisica de Altas Energias, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico Distrito Federal 04510 (Mexico)

2009-06-19T23:59:59.000Z

480

Holographic Bound on Information in Inflationary Perturbations  

E-Print Network (OSTI)

The formation of frozen classical perturbations from vacuum quantum fluctuations during inflation is described as a unitary quantum process with apparent "decoherence" caused by the expanding spacetime. It is argued that the maximum observable information content per comoving volume in classical modes is subject to the covariant entropy bound at the time those modes decohere, leading to a new quantitative bound on the information contained in frozen field modes in phase space. This bound implies holographic correlations of large-scale cosmological perturbations that may be observable.

Craig J. Hogan

2004-06-20T23:59:59.000Z

Note: This page contains sample records for the topic "leventis theo covary" 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.


481

Final Technical Report Interannual Variations in the Rate of Carbon Storage by a Mid-Latitude Forest  

Science Conference Proceedings (OSTI)

The time series of Net Ecosystem Exchange (NEE) of carbon by an entire forest ecosystem on time scales from hourly to decadal was measured by eddy-covariance supplemented with plot-level measurements of biomass and tree demography. The results demonstrate the response of forest carbon fluxes and long-term budgets to climatic factors and to successional change. The data from this project have been extensively used worldwide by the carbon cycle science community in support of model development and validation of remote sensing observations.

Wofsy, Steven; Munger, J W

2012-07-31T23:59:59.000Z

482

Relations between health indicators and residential proximity to coal mining in West Virginia  

SciTech Connect

We used data from a survey of 16493 West Virginians merged with county-level coal production and other covariates to investigate the relations between health indicators and residential proximity to coal mining. Results of hierarchical analyses indicated that high levels of coal production were associated with worse adjusted health status and with higher rates of cardiopulmonary disease, chronic obstructive pulmonary disease, hypertension, lung disease, and kidney disease. Research is recommended to ascertain the mechanisms, magnitude, and consequences of a community coal-mining exposure effect.

Hendryx, M.; Ahern, M.M. [West Virginia University, Morgantown, WV (United States). Dept. for Community Medicine

2008-04-15T23:59:59.000Z

483

Maximal output purity and capacity for asymmetric unital qudit channels  

E-Print Network (OSTI)

We consider generalizations of depolarizing channels to maps in which the identity channel is replaced by a convex combinations of unitary conjugations. We show that one can construct unital channels of this type for which the input which achieves maximal output purity is unique. We give conditions under which multiplicativity of the maximal p-norm and additivity of the minimal output entropy. We also show that the Holevo capacity need not equal log d - the minimal entropy as one might expect for a convex combination of unitary conjugations. Conversely, we give examples for which this condition holds, but the channel has no evident covariance properties.

Nilanjana Datta; Mary Beth Ruskai

2005-05-08T23:59:59.000Z

484

Comment on Higgs Inflation and Naturalness  

E-Print Network (OSTI)

We rebut the recent claim (arXiv:0912.5463) that Einstein-frame scattering in the Higgs inflation model is unitary above the cut-off energy Lambda ~ Mp/xi. We show explicitly how unitarity problems arise in both the Einstein and Jordan frames of the theory. In a covariant gauge they arise from non-minimal Higgs self-couplings, which cannot be removed by field redefinitions because the target space is not flat. In unitary gauge, where there is only a single scalar which can be redefined to achieve canonical kinetic terms, the unitarity problems arise through non-minimal Higgs-gauge couplings.

C. P. Burgess; Hyun Min Lee; Michael Trott

2010-02-13T23:59:59.000Z

485

A Possible Anisotropy in Blackbody Radiation Viewed through Non-uniform Gaseous Matter  

E-Print Network (OSTI)

A non-local gauge symmetry of a complex scalar field, which can be trivially extended to spinor fields, was demonstrated in a recent paper (Mod.Phys.Lett. A13, 1265 (1998) ; hep-th/9902020). The corresponding covariant Lagrangian density yielded a new, non-local Quantum Electrodynamics. In this letter we show that as a consequence of this new QED, a blackbody radiation viewed through gaseous matter appears to show a slight deviation from the Planck formula, and propose an experimental test to check this effect. We also show that a non-uniformity in this gaseous matter distribution leads to an (apparent) spatial anisotropy in the blackbody radiation.

T K Rai Dastidar

1999-03-12T23:59:59.000Z

486

Relaxation dynamics of a quantum Brownian particle in an ideal gas  

E-Print Network (OSTI)

We show how the quantum analog of the Fokker-Planck equation for describing Brownian motion can be obtained as the diffusive limit of the quantum linear Boltzmann equation. The latter describes the quantum dynamics of a tracer particle in a dilute, ideal gas by means of a translation-covariant master equation. We discuss the type of approximations required to obtain the generalized form of the Caldeira-Leggett master equation, along with their physical justification. Microscopic expressions for the diffusion and relaxation coefficients are obtained by analyzing the limiting form of the equation in both the Schroedinger and the Heisenberg picture.

Bassano Vacchini; Klaus Hornberger

2007-06-29T23:59:59.000Z

487

N*(1535) electroproduction at high Q2  

Science Conference Proceedings (OSTI)

A covariant spectator quark model is applied to study the {gamma}N {yields} N*(1535) reaction in the large Q{sup 2} region. Starting from the relation between the nucleon and N*(1535) systems, the N*(1535) valence quark wave function is determined without the addition of any parameters. The model is then used to calculate the {gamma}N {yields} N*(1535) transition form factors. A very interesting, useful relation between the A{sub 1/2} and S{sub 1/2} helicity amplitudes for Q{sup 2} > GeV{sup 2}, is also derived.

G. Ramalho, M.T. Pena, K. Tsushima

2012-04-01T23:59:59.000Z

488

Delta and Omega electromagnetic form factors in a Dyson-Schwinger/Bethe-Salpeter approach  

SciTech Connect

We investigate the electromagnetic form factors of the Delta and the Omega baryons within the Poincare-covariant framework of Dyson-Schwinger and Bethe-Salpeter equations. The three-quark core contributions of the form factors are evaluated by employing a quark-diquark approximation. We use a consistent setup for the quark-gluon dressing, the quark-quark bound-state kernel and the quark-photon interaction. Our predictions for the multipole form factors are compatible with available experimental data and quark-model estimates. The current-quark mass evolution of the static electromagnetic properties agrees with results provided by lattice calculations.

Diana Nicmorus, Gernot Eichmann, Reinhard Alkofer

2010-12-01T23:59:59.000Z

489

Bayesian nonlinear regression for large p small n problems  

Science Conference Proceedings (OSTI)

Statistical modeling and inference problems with sample sizes substantially smaller than the number of available covariates are challenging. This is known as large p small n problem. Furthermore, the problem is more complicated when we have multiple ... Keywords: 62F15, 62G08, 62H99, 62J02, 62M20, Bayesian hierarchical model, Empirical Bayes, Gibbs sampling, Markov chain Monte Carlo, Metropolis-Hastings algorithm, Near infrared spectroscopy, Relevance vector machine, Reproducing kernel Hilbert space, Support vector machine, Vapnik's ?-insensitive loss

Sounak Chakraborty; Malay Ghosh; Bani K. Mallick

2012-07-01T23:59:59.000Z

490

New framework for studying spherically symmetric static solutions in f(R) gravity  

Science Conference Proceedings (OSTI)

We develop a new covariant formalism to treat spherically symmetric spacetimes in metric f(R) theories of gravity. Using this formalism we derive the general equations for a static and spherically symmetric metric in a general f(R) gravity. These equations are used to determine the conditions for which the Schwarzschild metric is the only vacuum solution with vanishing Ricci scalar. We also show that our general framework provides a clear way of showing that the Schwarzschild solution is not a unique static spherically symmetric solution, providing some insight into how the current form of Birkhoff's theorem breaks down for these theories.

Nzioki, Anne Marie; Goswami, Rituparno [Astrophysics, Cosmology and Gravity Centre (ACGC), University of Cape Town, Rondebosch, 7701 (South Africa); Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch, 7701 (South Africa); Carloni, Sante [Institut d'Estudis Espacials de Catalunya (IEEC), Campus UAB, Facultat Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Dunsby, Peter K. S. [Astrophysics, Cosmology and Gravity Centre (ACGC), University of Cape Town, Rondebosch, 7701 (South Africa); Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch, 7701 (South Africa); South African Astronomical Observatory, Observatory, Cape Town (South Africa)

2010-04-15T23:59:59.000Z

491

Manifestly Gauge Invariant QCD  

E-Print Network (OSTI)

Building on recent work in SU(N) Yang-Mills theory, we construct a manifestly gauge invariant exact renormalization group for QCD. A gauge invariant cutoff is constructed by embedding the physical gauge theory in a spontaneously broken SU(N|N) gauge theory, regularized by covariant higher derivatives. Intriguingly, the construction is most efficient if the number of flavours is a multiple of the number of colours. The formalism is illustrated with a very compact calculation of the one-loop beta function, achieving a manifestly universal result and without fixing the gauge.

Tim R. Morris; Oliver J. Rosten

2006-06-20T23:59:59.000Z

492

Electroweak Radiative Corrections to the Parity-violating Asymmetry for SLAC Experiment E158  

SciTech Connect

Electroweak radiative corrections to observable quantities of Moeller scattering of polarized particles are calculated. We emphasize the contribution induced by infrared divergent parts of cross section. The covariant method is used to remove infrared divergences, so that our results do not involve any unphysical parameters. When applied to the kinematics of SLAC E158 experiment, these corrections reduce the parity violating asymmetry by about -6.5% at E = 48 GeV and y = 0.5, and kinematically weighted 'hard' bremsstrahlung effect for SLAC E158 is {approx} 1%.

Zykunov, Vladimir A.; /Gomel State Tech. U.

2012-04-04T23:59:59.000Z

493

Classical 5D fields generated by a uniformly accelerated point source  

E-Print Network (OSTI)

Gauge fields associated with the manifestly covariant dynamics of particles in $(3,1)$ spacetime are five-dimensional. In this paper we explore the old problem of fields generated by a source undergoing hyperbolic motion in this framework. The 5D fields are computed numerically using absolute time $\\tau$-retarded Green-functions, and qualitatively compared with Maxwell fields generated by the same motion. We find that although the zero mode of all fields coincides with the corresponding Maxwell problem, the non-zero mode should affect, through the Lorentz force, the observed motion of test particles.

I. Aharonovich; L. P. Horwitz

2009-10-18T23:59:59.000Z

494

Electronic noise-free measurements of squeezed light  

E-Print Network (OSTI)

We study the implementation of a correlation measurement technique for the characterization of squeezed light. We show that the sign of the covariance coefficient revealed from the time resolved correlation data allow us to distinguish between squeezed, coherent and thermal states. In contrast to the traditional method of characterizing squeezed light, involving measurement of the variation of the difference photocurrent, the correlation measurement method allows to eliminate the contribution of the electronic noise, which becomes a crucial issue in experiments with dim sources of squeezed light.

Leonid A. Krivitsky; Ulrik L. Andersen; Ruifang Dong; Alexander Huck; Christoffer Wittmann; Gerd Leuchs

2008-07-09T23:59:59.000Z

495

Complete calculation of evaluated Maxwellian-averaged cross sections and their uncertainties for s-process nucleosynthesis  

Science Conference Proceedings (OSTI)

Present contribution represents a significant improvement of our previous calculation of Maxwellian-averaged cross sections and astrophysical reaction rates. Addition of newly-evaluated neutron reaction libraries, such as ROSFOND and Low-Fidelity Covariance Project, and improvements in data processing techniques allowed us to extend it for entire range of sprocess nuclei, calculate Maxwellian-averaged cross section uncertainties for the first time, and provide additional insights on all currently available neutron-induced reaction data. Nuclear reaction calculations using ENDF libraries and current Java technologies will be discussed and new results will be presented.

Pritychenko, B.

2010-07-19T23:59:59.000Z

496

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this survey we discuss various aspects of symmetry energy in the framework of nuclear density functional theory, considering both non-relativistic and relativistic self-consistent mean-field realizations side-by-side. Key observables pertaining to bulk nucleonic matter and finite nuclei are reviewed. Constraints on the symmetry energy and correlations between observables and symmetry-energy parameters, using statistical covariance analysis, are investigated. Perspectives for future work are outlined in the context of ongoing experimental efforts.

W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar

2013-07-22T23:59:59.000Z

497

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this survey we discuss various aspects of symmetry energy in the framework of nuclear density functional theory, considering both non-relativistic and relativistic self-consistent mean-field realizations side-by-side. Key observables pertaining to bulk nucleonic matter and finite nuclei are reviewed. Constraints on the symmetry energy and correlations between observables and symmetry-energy parameters, using statistical covariance analysis, are investigated. Perspectives for future work are outlined in the context of ongoing experimental efforts.

Nazarewicz, W; Satula, W; Vretenar, D

2013-01-01T23:59:59.000Z

498

Modification of the Bel-Robinson type energy-momentum  

E-Print Network (OSTI)

For describing the non-negative gravitational energy-momentum in terms of a pure Bel-Robinson type energy-momentum in a quasilocal 2-surface, both the Bel-Robinson tensor $B$ and tensor $V$ are suitable. We found that this Bel-Robinson type energy-momentum can be modified such that it satisfies the Lorentz covariant, future pointing and non-spacelike properties. We find that these particular energy-momentum properties can be obtained from (i): $B$ or $V$ plus a tensor $S$ in a quasilocal small cube limit, or (ii): directly evaluating the energy-momentum of $B$ or $V$ in a quasilocal small box region.

Lau Loi So

2013-02-11T23:59:59.000Z

499

Classical and Bayesian inference in neuroimaging: Theory  

E-Print Network (OSTI)

This paper reviews hierarchical observation models, used in functional neuroimaging, in a Bayesian light. It emphasizes the common ground shared by classical and Bayesian methods to show that conventional analyses of neuroimaging data can be usefully extended within an empirical Bayesian framework. In particular we formulate the procedures used in conventional data analysis in terms of hierarchical linear models and establish a connection between classical inference and parametric empirical Bayes (PEB) through covariance component estimation. This estimation is based on an expectation maximization or EM algorithm. The key point is that hierarchical models not only provide for appropriate inference at the highest level but that one can revisit lower levels suitably

K. J. Friston; W. Penny; C. Phillips; S. Kiebel; G. Hinton; J. Ashburner

2002-01-01T23:59:59.000Z

500

Bayesian estimation of pulsar parameters from gravitational wave data  

E-Print Network (OSTI)

We present a method of searching for, and parameterizing, signals from known radio pulsars in data from interferometric gravitational wave detectors. This method has been applied to data from the LIGO and GEO 600 detectors to set upper limits on the gravitational wave emission from several radio pulsars. Here we discuss the nature of the signal and the performance of the technique on simulated data. We show how to perform a coherent multiple detector analysis and give some insight in the covariance between the signal parameters.

Réjean J. Dupuis; Graham Woan

2005-08-23T23:59:59.000Z