Sample records for maximum luminous efficacy

  1. Luminous Efficacy Standards for General Purpose Lights

    Broader source: Energy.gov [DOE]

    Assembly Bill 178, adopted in June 2007, established efficacy* standards for general purpose lights sold in the state of Nevada. The bill set the required efficacy at 25 lumens per watt (lm/W) of...

  2. Inves&ga&ng the Trade-Off between Luminous Efficacy of Radia&on

    E-Print Network [OSTI]

    California at Davis, University of

    Inves&ga&ng the Trade-Off between Luminous Efficacy of Radia&on and Color;Luminous Efficacy of Radia&on (LER) / Color Rendering Index (CRI) Trade-off study CCT = 3500 K How can we experimentally test this? #12;Luminous Efficacy

  3. Vision Research 40 (2000) 11571165 Local luminance factors that determine the maximum disparity for

    E-Print Network [OSTI]

    Kingdom, Frederick A. A.

    2000-01-01T23:59:59.000Z

    Vision Research 40 (2000) 1157­1165 Local luminance factors that determine the maximum disparity dense arrays of micropatterns, whose luminance characteristics were manipulated. In Experiment 1, we with luminance spatial frequency and with Gabor size, but was constant for a constant bandwidth (frequency times

  4. A simple evaluation of global and diffuse Luminous Efficacy for all sky conditions in tropical and humid climate

    E-Print Network [OSTI]

    Boyer, Edmond

    1 A simple evaluation of global and diffuse Luminous Efficacy for all sky conditions in tropical to determine luminous efficacy under different sky conditions. A comparison between these empirical constants. Keywords Global and diffuse luminous efficacy, different sky conditions, solar irradiance, solar

  5. Warm-white light-emitting diodes integrated with colloidal quantum dots for high luminous

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    Warm-white light-emitting diodes integrated with colloidal quantum dots for high luminous efficacy NQD-LED design with both high luminous efficacy of optical radiation and CRI is presented to have luminous efficacy of optical ra- diation (LER), which is challenging using conventional phosphors

  6. Computational study of power conversion and luminous efficiency performance for

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    Computational study of power conversion and luminous efficiency performance for semiconductor) and luminous efficiency (LE) performance levels of high photometric quality white LEDs integrated with quantum dots (QDs) achieving an averaged color rendering index of 90 (with R9 at least 70), a luminous efficacy

  7. The Most Luminous Starbursts in the Universe

    E-Print Network [OSTI]

    Daniel W. Weedman; James R. Houck

    2008-06-25T23:59:59.000Z

    A summary of starburst luminosities based on PAH features is given for 243 starburst galaxies with 0 luminous starbursts observed. Empirical calibrations of vLv(7.7um) are used to determine bolometric luminosity Lir and the star formation rate (SFR) for these starbursts. The most luminous starbursts found in this sample have log Lir = 45.4(+-0.3) + 2.5(+-0.3)log(1+z), in ergs per s, and the maximum star formation rates for starbursts in units of solar masses per yr are log(SFR) = 2.1(+-0.3) + 2.5(+-0.3)log(1+z), up to z = 2.5. The exponent for pure luminosity evolution agrees with optical and radio studies of starbursts but is flatter than previous results based in infrared source counts. The maximum star formation rates are similar to the maxima determined for submillimeter galaxies; the most luminous individual starburst included within the sample has log Lir = 46.9, which gives a SFR = 3400 solar masses per yr.

  8. Luminous "Dark" Halos

    E-Print Network [OSTI]

    Mark A. Walker

    2000-08-07T23:59:59.000Z

    Several lines of evidence suggest that cold, dense gas clouds make a substantial contribution to the total mass of dark halos. If so then physical collisions between clouds must occur; these cause strong, radiative shocks to propagate through the cold gas, with the startling implication that all ``dark'' halos must be luminous. The expected luminosity is a strong function of halo velocity dispersion, and should contribute a significant fraction of the observed X-ray emission from clusters of galaxies, if dark halos are predominantly made of cold gas. Existing data do not exclude this possibility; indeed two particular expectations of the luminous-halo model are borne out in the X-ray data, and thus give support to the cold-cloud dark matter model. First we find a luminosity-temperature correlation of the form L proportional to T to the power 11/4, as seen in recent analyses of cluster samples. Secondly the anticipated spectra have substantially more power at low energies than isothermal bremsstrahlung spectra, and might account for the observed ``excess'' EUV emission seen from some clusters. The successes of the luminous-halo model are particularly remarkable because the theory has no free parameters or ad hoc elements. The model can be tested by the X-ray satellite Chandra, which should resolve the Virgo cluster into 10,000 point-like, transient X-ray sources. Non-detection of any such sources by Chandra can constrain the contribution of cold gas clouds to below 1% of the total matter density in the Universe, assuming Virgo to be representative.

  9. Maps of sky luminance at various altitudes

    E-Print Network [OSTI]

    Duntley, Seibert Q; Bioleau, A R; Harris, J L; Gordon, J

    1960-01-01T23:59:59.000Z

    expressed in foot-lamberts. Luminance SID REFERENCE 60-12 214. Upper hemisphere luminance distribution. is expressedin foot-lamberts. Luminance SIO REFERENCE 60-12 21 SEPTEMBER

  10. Ratio model serves suprathreshold color luminance discrimination

    E-Print Network [OSTI]

    Mullen, Kathy T.

    Ratio model serves suprathreshold color­ luminance discrimination Marcel J. Sankeralli and Kathy T quadrants of the red­ green/luminance and blue­yellow/luminance planes of cardinal color space. We showed model of suprathreshold color­luminance dis- crimination, in which discrimination depends on a ratio

  11. Accreting White Dwarfs among the Planetary Nebulae Most Luminous in [O III]5007 Emission

    E-Print Network [OSTI]

    Noam Soker

    2005-12-06T23:59:59.000Z

    I propose that some of the most luminous planetary nebulae (PNs) are actually proto-PNs, where a companion white dwarf (WD) accretes mass at a relatively high rate from the post-asymptotic giant branch star that blew the nebula. The WD sustains a continuous nuclear burning and ionizes the nebula. The WD is luminous enough to make the dense nebula luminous in the [O III]5007 line, In young stellar populations these WD accreting systems account for a small fraction of [O III]-luminous PNs, but in old stellar populations these binaries might account for most, or even all, of the [OIII]-luminous PNs. This might explain the puzzling constant cutoff (maximum) [O III]5007 luminosity of the planetary nebula luminosity function across different galaxy types.

  12. OBSERVATIONS OF TWO TRANSIENT LUMINOUS EVENT-

    E-Print Network [OSTI]

    Rutledge, Steven

    OBSERVATIONS OF TWO TRANSIENT LUMINOUS EVENT- PRODUCING MESOSCALE CONVECTIVE SYSTEMS Timothy LangC by positive cloud-to-ground (+CG) lightning can lead to transient luminous events (TLEs; Williams 1998; Lyons

  13. Luminant restores pre-owned draglines

    SciTech Connect (OSTI)

    Donovan, A.

    2009-11-15T23:59:59.000Z

    Luminant, a Texas-based coal producer, brings two draglines back to life by moving and refurbishing them. 10 photos.

  14. Sandia National Laboratories: high luminous efficacy of radiation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Updated: May 23, 2013 Go To Top Exceptional service in the national interest EC About Energy and Climate (EC) Energy Security Climate Security Infrastructure Security Energy...

  15. PERCEIVED SPEED INCREASES AT LOW LUMINANCE

    E-Print Network [OSTI]

    Pashkam, Maryam Vaziri

    PERCEIVED SPEED INCREASES AT LOW LUMINANCE Maryam Vaziri-Pashkam, Patrick Cavanagh Vision Sciences Laboratory, Department of Psychology, Harvard University Discussion Does changing the mean luminance is increased as the mean luminance of the grating decreases. Conclusion First Experiment: Stimuli were radial

  16. Multiple Sclerosis Luminance Threshold and Measurements

    E-Print Network [OSTI]

    Foster, David H.

    Multiple Sclerosis Luminance Threshold and Measurements of Temporal Characteristics of Vision Definite MS + 6/9 - + + 7/50/F Recurrent ON + 6/6 + - + 8/47/F Definite MS + 6/6 + + + · Luminance to te t the temporal properties of vi Ion were equalized with respect to Individual luminance thresh

  17. Luminant Energy | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer Plant Jump to:Landowners andLodgepole,Lotsee,EnergyAlabama:Ludlow Falls,Luling,LumenLuminant

  18. The metallicities of luminous, massive field galaxies at intermediate redshifts

    E-Print Network [OSTI]

    M. Mouhcine; S. P. Bamford; A. Aragon-Salamanca; O. Nakamura

    2006-03-23T23:59:59.000Z

    We derive oxygen abundances for a sample of 40 luminous (M_{B} = 0.45. Oxygen abundances, relative to hydrogen, of the interstellar emitting gas are estimated by means of the empirically calibrated strong emission line ratio technique. The derived (12+log(O/H)) values range from 8.4 to 9.0, with a median of 8.7. Twenty of these galaxies have securely measured rotation velocities, in the range 50--244 km/s. The measured emission line equivalent widths and diagnostic ratios for the intermediate redshift galaxies cover similar ranges to those observed across a large sample of local galaxies. The estimated oxygen abundances for our luminous star-forming intermediate redshift galaxies cover the same range as their local counterparts. However, at a given galaxy luminosity, many of our galaxies have significantly lower oxygen abundances, i.e., $(12+log(O/H))~8.6$, than local galaxies with similar luminosities. Interestingly, these luminous, massive, intermediate redshift, star-forming galaxies with low oxygen abundances exhibit physical conditions, i.e., emission line equivalent width and ionization state, very similar to those of local faint and metal-poor star-forming galaxies. The oxygen abundance of the interstellar gas does not seem to correlate with the maximum rotation velocity or the emission scale length of the parent galaxy. This suggests that there is a diversity in the intrinsic properties of the massive field galaxy population at intermediate redshifts (ABRIDGED).

  19. Infants' use of luminance information in object individuation

    E-Print Network [OSTI]

    Woods, Rebecca Jindalee

    2004-09-30T23:59:59.000Z

    object interactions. One way to test these hypotheses is to investigate infants' ability to individuate objects based on luminance. Luminance is detected at birth, so, according to the visual maturation hypothesis, luminance, like shape and size...

  20. Constancy of built-in luminance meter measurements in diagnostic displays

    SciTech Connect (OSTI)

    Silosky, M., E-mail: michael.silosky@ucdenver.edu; Marsh, R. M. [Department of Radiology, University of Colorado, School of Medicine Aurora, Colorado 80045 (United States)] [Department of Radiology, University of Colorado, School of Medicine Aurora, Colorado 80045 (United States)

    2013-12-15T23:59:59.000Z

    Purpose: Liquid crystal displays used to interpret medical images are often equipped with built-in luminance meters to evaluate luminance response and Grayscale Standard Display Function conformance. This work evaluates agreement between luminance reported by the built-in meters and external measurements. Methods: The white level luminance was measured using a built-in meter and an external meter for 93 primary review workstations (Models MFGD 3420 and MDCG 3120-CB) with between 117 and 49?336 backlight hours (BLH). Measured luminance values were compared viat-test for displays with less than 25?000 BLH and those with more than 25?000 BLH. Bias between meters was also evaluated. Changes in luminance uniformity with increasing backlight hours were explored by determining the maximum luminance deviation (MLD) for subsets of these displays with less than 800 BLH and greater than 35?000 BLH. Results: The mean difference between built-in and external luminance measurements was 5.84% and 38.92% for displays with less than 25?000 and greater than 25?000 BLH, respectively, with a statistically significant difference in the means (p < 0.001). For displays with low BLH, a statistically significant bias was observed (p < 0.001) between built-in and external measurements. A high degree of correlation was observed between measurements made with two separate external meters (r = 0.999). The mean MLD was 9.5% and 11.2% for MDCG 3120-CB displays with less than 800 and greater than 35?000 BLH, respectively. The difference in the mean values was not statistically significant (p < 0.001). Conclusions: Disagreement between the white level luminance measured using the built-in and external meter increased with BLH. Consequently, reliance on values reported by the built-in luminance meter may result in a reduction in image contrast with time. Recommendations have been proposed regarding luminance response testing and corrective action for failing displays.

  1. Interactions between colour and luminance contrast in the perception of

    E-Print Network [OSTI]

    Mullen, Kathy T.

    Interactions between colour and luminance contrast in the perception of motion K. T. Mullen Mc their luminance counterparts. We have examined the effect on perceived velocity of adding luminance contrast to an isoluminant chromatic stimulus. We show that moving luminance contrast 'captures" colour so that a combined

  2. Enhanced luminance of organic light-emitting diodes with metal nanoparticle electron injection layer

    E-Print Network [OSTI]

    Liu, Deang; Fina, Michael; Ren, Li; Mao, Samuel S.

    2009-01-01T23:59:59.000Z

    electron injection and luminance characteristics. The small009-5199-x Enhanced luminance of organic light-emittinglayer. Improved current and luminance characteristics were

  3. Evaluation of High Dynamic Range Photography as a Luminance Mapping Technique

    E-Print Network [OSTI]

    Inanici, Mehlika; Galvin, Jim

    2004-01-01T23:59:59.000Z

    Illuminance Meters and Luminance Meters: Performance,9505 ? B In calculating luminance (L), CIE Y is multipliedB. and Dumortier, D. “Luminance Calibration of the Nikon

  4. A New Luminous Blue Variable in M31

    E-Print Network [OSTI]

    Humphreys, Roberta M; Gordon, Michael S

    2015-01-01T23:59:59.000Z

    We report the fifth confirmed Luminous Blue Variable/S Doradus variable in M31. In 2006, J004526.62+415006.3 had the spectrum of hot Fe II emission line star with strong P Cygni profiles in the Balmer lines. In 2010, its absorption line spectrum resembled an early A-type supergiant with H and Fe II emission lines with strong P Cygni profiles, and in 2013 the spectrum had fully transitioned to an F-type supergiant due to the formation of the optically thick, cool wind which characterizes LBVs at maximum light. The photometric record supports the LBV/S Dor nature of the variability. Its bolometric luminosity ~ -9.65 mag places it on the HR Diagram near the known LBVs, AE And, Var C in M33 and S Dor.

  5. Object individuation in infancy: the value of color and luminance

    E-Print Network [OSTI]

    Woods, Rebecca Jindalee

    2009-06-02T23:59:59.000Z

    The ability to individuate objects is one of our most fundamental cognitive capacities. Recent research has revealed that, when objects vary in color or luminance alone, infants fail to individuate until 11.5 months. However, color and luminance...

  6. Explosions inside Ejecta and Most Luminous Supernovae

    E-Print Network [OSTI]

    S. I. Blinnikov

    2008-12-28T23:59:59.000Z

    The extremely luminous supernova SN2006gy is explained in the same way as other SNIIn events: light is produced by a radiative shock propagating in a dense circumstellar envelope formed by a previous weak explosion. The problems in the theory and observations of multiple-explosion SNe IIn are briefly reviewed.

  7. Atmospheric optical measurements during high altitude balloon flight, Part II: Sky luminances

    E-Print Network [OSTI]

    Boileau, Almerian R

    1961-01-01T23:59:59.000Z

    BALLOON FLIGHT, PART II, SKY LUMINANCES Almerian R. Boileaufor Luminance Plots', Fig. 6 Sky Luminance vs Altitude, Fig.7, et seq. Sky Luminance vs Altitude, Fig. 25, et seq.

  8. Jose Groh (Geneva Observatory, Switzerland) Luminous Blue Variables

    E-Print Network [OSTI]

    Crowther, Paul

    Jose Groh (Geneva Observatory, Switzerland) Luminous Blue Variables: massive stars extremely close Groh - Luminous BlueVariables: massive stars extremely close to the Eddington limit JD2:Very massive Jose Groh - Luminous BlueVariables: massive stars extremely close to the Eddington limit JD2:Very

  9. Abnormalities of chromatic and luminance critical flicker frequency in

    E-Print Network [OSTI]

    Foster, David H.

    Abnormalities of chromatic and luminance critical flicker frequency in multiple sclerosis Robert J*** Criticalflickerfrequency (CFF) was measuredfor stimuli varying in chromaticity only and in luminance onlyfor patients underlying linear interdependencies for the two groups, consistent with a greater loss of temporal luminance

  10. The Formation of Primordial Luminous Objects

    E-Print Network [OSTI]

    Emanuele Ripamonti; Tom Abel

    2005-07-06T23:59:59.000Z

    In these lecture notes we review the current knowledge about the formation of the first luminous objects. We start from the cosmological context of hierarchical models of structure formation, and discuss the main physical processes which are believed to lead to primordial star formation, i.e. the cooling processes and the chemistry of molecules (especially H2) in a metal-free gas. We then describe the techniques and results of numerical simulations, which indicate that the masses of the first luminous objects are likely to be much larger than that of present-day stars. Finally, we discuss the scenario presented above, exposing some of the most interesting problems which are currently being investigated, such as that of the feedback effects of these objects.

  11. Radiative Flow in a Luminous Disk II

    E-Print Network [OSTI]

    Jun Fukue

    2006-01-07T23:59:59.000Z

    Radiatively-driven transfer flow perpendicular to a luminous disk is examined in the subrelativistic regime of $(v/c)^1$, taking into account the gravity of the central object. The flow is assumed to be vertical, and the gas pressure is ignored, while internal heating is assumed to be proportional to the gas density. The basic equations were numerically solved as a function of the optical depth, and the flow velocity, the height, the radiative flux, and the radiation pressure were obtained for a given radius, an initial optical depth, and initial conditions at the flow base (disk ``inside''), whereas the mass-loss rate was determined as an eigenvalue of the boundary condition at the flow top (disk ``surface''). For sufficiently luminous cases, the flow resembles the case without gravity. For less-luminous cases, however, the flow velocity decreases, and the flow would be impossible due to the existence of gravity in the case that the radiative flux is sufficiently small. Application to a supercritical accretion disk with mass loss is briefly discussed.

  12. AN EXTENDED GRID OF NOVA MODELS. III. VERY LUMINOUS, RED NOVAE

    SciTech Connect (OSTI)

    Shara, Michael M.; Zurek, David [Department of Astrophysics, American Museum of Natural History, Central Park West and 79th Street, New York, NY 10024-5192 (United States); Yaron, Ofer; Prialnik, Dina; Kovetz, Attay [Department of Geophysics and Planetary Sciences, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978 (Israel)

    2010-12-10T23:59:59.000Z

    Extremely luminous, red eruptive variables like RV in M31 are being suggested as exemplars of a new class of astrophysical objects. Our greatly extended series of nova simulations shows that classical nova models can produce very red, luminous eruptions. In a poorly studied corner of three-dimensional nova parameter space (very cold, low-mass white dwarfs, accreting at very low rates) we find bona fide classical novae that are very luminous and red because they eject very slowly moving, massive envelopes. A crucial prediction of these nova models-in contrast to the predictions of merging star ('mergeburst') models-is that a hot remnant, the underlying white dwarf, will emerge after the massive ejected envelope has expanded enough to become optically thin. This blue remnant must fade on a timescale of decades-much faster than a 'mergeburst', which must fade on timescales of millennia or longer. Furthermore, the cooling nova white dwarf and its expanding ejecta must become redder in the years after eruption, while a contracting mergeburst must become hotter and bluer. We predict that red novae will always brighten to L {approx} 1000 L{sub sun} for about one year before rising to the maximum luminosity at L {approx} 10{sup 6}-10{sup 7} L{sub sun}. The maximum luminosity attainable by a nova is likely to be L {approx} 10{sup 7} L{sub sun}, corresponding to M {approx} -12. In an accompanying paper, we describe a fading, luminous blue candidate for the remnant of M31-RV; it is observed with the Hubble Space Telescope to be compatible only with the nova model.

  13. MELE: Maximum Entropy Leuven Estimators

    E-Print Network [OSTI]

    Paris, Quirino

    2001-01-01T23:59:59.000Z

    of the Generalized Maximum Entropy Estimator of the Generaland Douglas Miller, Maximum Entropy Econometrics, Wiley andCalifornia Davis MELE: Maximum Entropy Leuven Estimators by

  14. Maximum Parsimony and Maximum Likelihood Methods Comparisons and Bootstrap Tests

    E-Print Network [OSTI]

    Qiu, Weigang

    Maximum Parsimony and Maximum Likelihood Methods Comparisons and Bootstrap Tests Character Likelihood Methods Comparisons and Bootstrap Tests Character Reconstruction PHYLIP and T-REX Exercises Outline 1 Maximum Parsimony and Maximum Likelihood 2 Methods Comparisons and Bootstrap Tests 3 Character

  15. Maximum Entropy Correlated Equilibria

    E-Print Network [OSTI]

    Ortiz, Luis E.

    2006-03-20T23:59:59.000Z

    We study maximum entropy correlated equilibria in (multi-player)games and provide two gradient-based algorithms that are guaranteedto converge to such equilibria. Although we do not provideconvergence rates for these ...

  16. Linda Lighton's Luminous: A review by Tanya Hartman

    E-Print Network [OSTI]

    Hartman, Tanya

    2011-01-01T23:59:59.000Z

    Luminous A Review by Tanya Hartman Linda Lighton’s Life is not a series of gig lamps symmetrically arranged; life is a luminous halo, a semi-transparent envelope surrounding us from the beginning of consciousness to the end. – Virginia Woolf... but instead to be experienced as healing collec- tive. In short, Lighton has moved her work from the corporeality of the driven object to the spirituality of installed sanctuary. The word luminous connotes intelligence, enlight- enment and transcendence...

  17. Generating Luminous and Dark Matter During Inflation

    E-Print Network [OSTI]

    Barrie, Neil D

    2015-01-01T23:59:59.000Z

    We propose a new mechanism for generating both luminous and dark matter during cosmic inflation. According to this mechanism, ordinary and dark matter carry common charge which is associated with an anomalous $ U(1)_{X} $ group. Anomaly terms source $ \\mathcal{CP} $ and $ U(1)_{X} $ charge violating processes during inflation, producing corresponding non-zero Chern-Simons numbers which are subsequently reprocessed into baryon and dark matter densities. The general framework developed is then applied to two possible extensions of the Standard Model with anomalous gauged $B$ and $B-L$, each with an additional dark matter candidate.

  18. Generating Luminous and Dark Matter During Inflation

    E-Print Network [OSTI]

    Neil D. Barrie; Archil Kobakhidze

    2015-03-09T23:59:59.000Z

    We propose a new mechanism for generating both luminous and dark matter during cosmic inflation. According to this mechanism, ordinary and dark matter carry common charge which is associated with an anomalous $ U(1)_{X} $ group. Anomaly terms source $ \\mathcal{CP} $ and $ U(1)_{X} $ charge violating processes during inflation, producing corresponding non-zero Chern-Simons numbers which are subsequently reprocessed into baryon and dark matter densities. The general framework developed is then applied to two possible extensions of the Standard Model with anomalous gauged $B$ and $B-L$, each with an additional dark matter candidate.

  19. attenuates luminal apoptosis: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    patch Zanker, Johannes M. 257 Classical disordered ground states: Super-ideal gases and stealth and equi-luminous materials Chemistry Websites Summary: Classical disordered...

  20. antegrade colonic luminal: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    patch Zanker, Johannes M. 242 Classical disordered ground states: Super-ideal gases and stealth and equi-luminous materials Chemistry Websites Summary: Classical disordered...

  1. Visual Comfort Analysis of Innovative Interior and Exterior Shading Systems for Commercial Buildings using High Resolution Luminance Images

    E-Print Network [OSTI]

    Konis, Kyle

    2011-01-01T23:59:59.000Z

    Society of North America. Luminance ratio limits; ch. 11,range photography as a luminance mapping Technique. Lawrenceusing High Resolution Luminance Images Kyle Konis Lawrence

  2. EARLY PHASE OBSERVATIONS OF EXTREMELY LUMINOUS TYPE Ia SUPERNOVA 2009dc

    SciTech Connect (OSTI)

    Yamanaka, M.; Arai, A.; Chiyonobu, S.; Fukazawa, Y.; Ikejiri, Y.; Itoh, R.; Komatsu, T.; Miyamoto, H. [Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan); Kawabata, K. S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kinugasa, K.; Hashimoto, O.; Honda, S. [Gunma Astronomical Observatory, Takayama, Gunma 377-0702 (Japan); Tanaka, M. [Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Imada, A.; Kuroda, D. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Asakuchi-shi, Okayama 719-0232 (Japan); Maeda, K.; Nomoto, K. [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa (Japan); Kamata, Y. [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Kawai, N. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Konishi, K., E-mail: myamanaka@hiroshima-u.ac.j [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8582 (Japan)

    2009-12-20T23:59:59.000Z

    We present early phase observations in optical and near-infrared wavelengths for the extremely luminous Type Ia supernova (SN Ia) 2009dc. The decline rate of the light curve is DELTAm{sub 15}(B) = 0.65 +- 0.03, which is one of the slowest among SNe Ia. The peak V-band absolute magnitude is estimated to be M{sub V} = -19.90 +- 0.15 mag if no host extinction is assumed. It reaches M{sub V} = -20.19 +- 0.19 mag if we assume the host extinction of A{sub V} = 0.29 mag. SN 2009dc belongs to the most luminous class of SNe Ia, like SNe 2003fg and 2006gz. Our JHK{sub s} -band photometry shows that this SN is also one of the most luminous SNe Ia in near-infrared wavelengths. We estimate the ejected {sup 56}Ni mass of 1.2 +- 0.3 M{sub sun} for the no host extinction case (and of 1.6 +- 0.4 M{sub sun} for the host extinction of A{sub V} = 0.29 mag). The C II lambda6580 absorption line remains visible until a week after the maximum brightness, in contrast to its early disappearance in SN 2006gz. The line velocity of Si II lambda6355 is about 8000 km s{sup -1} around the maximum, being considerably slower than that of SN 2006gz. The velocity of the C II line is similar to or slightly less than that of the Si II line around the maximum. The presence of the carbon line suggests that the thick unburned C+O layer remains after the explosion. Spectropolarimetric observations by Tanaka et al. indicate that the explosion is nearly spherical. These observational facts suggest that SN 2009dc is a super-Chandrasekhar mass SN Ia.

  3. 26 February 2008 Significance of Transient Luminous Events to Neutral Chemistry: Experimental

    E-Print Network [OSTI]

    Otago, University of

    26 February 2008 Significance of Transient Luminous Events to Neutral Chemistry: Experimental it has been suggested that transient luminous events (TLE) occurring over thunderstorms may produce phenomena (see the review by Rodger [1999]), now collectively termed "Transient Luminous Events" (TLE

  4. Atmospheric optical measurements in western Florida, Flight 112, Part II: Sky luminances

    E-Print Network [OSTI]

    Boileau, Almerian R

    1960-01-01T23:59:59.000Z

    by which the sky luminance and radiance distributions wereRecording schedule. Sky luminance distribution data wereof Data Lines used for Sky Luminance P l o t s , Figure 4

  5. university-logo Maximum likelihood

    E-Print Network [OSTI]

    McCullagh, Peter

    university-logo Maximum likelihood Applications and examples REML and residual likelihood Peter McCullagh REML #12;university-logo Maximum likelihood Applications and examples JAN: Some personal remarks... IC #12;university-logo Maximum likelihood Applications and examples Outline 1 Maximum likelihood REML

  6. Eddington Capture Sphere around luminous stars

    E-Print Network [OSTI]

    Adam Stahl; Maciek Wielgus; Marek Abramowicz; W?odek Klu?niak; Wenfei Yu

    2012-08-10T23:59:59.000Z

    Test particles infalling from infinity onto a compact spherical star with a mildly super-Eddington luminosity at its surface are typically trapped on the "Eddington Capture Sphere" and do not reach the surface of the star. The presence of a sphere on which radiation pressure balances gravity for static particles was first discovered some twenty five years ago. Subsequently, it was shown to be a capture sphere for particles in radial motion, and more recently also for particles in non-radial motion, in which the Poynting-Robertson radiation drag efficiently removes the orbital angular momentum of the particles, reducing it to zero. Here we develop this idea further, showing that "levitation" on the Eddington sphere (above the stellar surface) is a state of stable equilibrium, and discuss its implications for Hoyle-Lyttleton accretion onto a luminous star. When the Eddington sphere is present, the cross-section of a compact star for actual accretion is typically less than the geometrical cross-section (pi Rsquared), direct infall onto the stellar surface only being possible for relativistic particles, with the required minimum particle velocity at infinity typically ~1/2 the speed of light. We further show that particles on typical trajectories in the vicinity of the stellar surface will also be trapped on the Eddington Capture Sphere.

  7. Correlation between Galaxy Mergers and Luminous AGN

    E-Print Network [OSTI]

    Hong, Jueun; Kim, Minjin; Ho, Luis C

    2015-01-01T23:59:59.000Z

    It is not yet clear what triggers the activity of active galactic nuclei (AGNs), but galaxy merging has been suspected to be one of the main mechanisms fuelling the activity. Using deep optical images taken at various ground-based telescopes, we investigate the fraction of galaxy mergers in 39 luminous AGNs (M$_{R}\\, \\lesssim$ -22.6 mag) at $z \\leq$ 0.3 (a median redshift of 0.155), of which the host galaxies are generally considered as early-type galaxies. Through visual inspection of the images, we find that 17 of 39 AGN host galaxies (43.6%) show the evidence for current or past mergers like tidal tails, shells, and disturbed morphology. In order to see if this fraction is abnormally high, we also examined the merging fraction of normal early-type galaxies in the Sloan Digital Sky Survey (SDSS) Strip 82 data (a median redshift of 0.04), of which the surface-brightness limit is comparable to our imaging data. To correct for the effects related to the redshift difference of the two samples, we performed an i...

  8. The growth of luminous red galaxies by merging

    E-Print Network [OSTI]

    Morad Masjedi; David W. Hogg; Michael R. Blanton

    2007-08-23T23:59:59.000Z

    We study the role of major and minor mergers in the mass growth of luminous red galaxies. We present small-scale ($0.01luminous early-type galaxies from the Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy (LRG) sample ($0.16luminous than $\\Lstar$. We integrate the luminosity accretion rate from mergers over all companion galaxy subsamples and find that LRGs are growing by $[1.7\\pm 0.1]$ percent per $\\Gyr$, on average, from merger activity at redshift $z\\sim 0.25$. This rate is almost certainly an over-estimate because we have assumed that all close pairs are merging as quickly as dynamical friction allows; nonetheless it is on the low side of the panoply of measurements in the literature, and lower than any rate predicted from theory.

  9. ASASSN-15lh: The Most Luminous Supernova Ever Discovered

    E-Print Network [OSTI]

    Dong, Subo; Prieto, J L; Jha, S W; Stanek, K Z; Holoien, T W -S; Kochanek, C S; Thompson, T A; Morrell, N; Thompson, I B; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Brown, J S; Chen, Ping; Conseil, E; Danilet, A B; Falco, E; Grupe, D; Kiyota, S; Masi, G; Nicholls, B; Olivares, F; Pignata, G; Pojmanski, G; Simonian, G V; Szczygiel, D M; Wozniak, P R

    2015-01-01T23:59:59.000Z

    We report the discovery and early evolution of ASASSN-15lh, the most luminous supernova ever found. At redshift z=0.2326, ASASSN-15lh reached an absolute magnitude of M_{u,AB} ~ -23.5 and bolometric luminosity L_bol ~ 2.2x10^45 ergs/s, which is >~ 2 times more luminous than any previously known supernova. Its spectra match the hydrogen-poor sub-class of super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are poorly understood. In contrast to known SLSNe-I, most of which reside in star-forming, dwarf galaxies, its host appears to be a luminous galaxy (M_V ~ -22; M_K ~ -25.1) with little star formation. In the two months since its first detection, ASASSN-15lh has radiated ~7.5x10^51 ergs, challenging the popular magnetar model for the engine of SLSNe-I.

  10. Luminance mechanisms mediate the motion of redgreen isoluminant gratings: the role of ``temporal chromatic aberration''

    E-Print Network [OSTI]

    Mullen, Kathy T.

    Luminance mechanisms mediate the motion of red­green isoluminant gratings: the role of ``temporal of variable luminance or chromatic noise. In the first experiment, we used dynamic luminance noise to show that direction thresholds for red­green grating motion are masked by luminance noise over the entire temporal

  11. Cancer Cell JARID1B Is a Luminal Lineage-Driving Oncogene

    E-Print Network [OSTI]

    Liu, X. Shirley

    Cancer Cell Article JARID1B Is a Luminal Lineage-Driving Oncogene in Breast Cancer Shoji Yamamoto,1 in luminal breast tumors and a somatic mutation in a basal-like breast cancer results in the gain of unique chromatin binding and luminal expression and splicing patterns. Downregulation of JARID1B in luminal cells

  12. STAR FORMATION IN TWO LUMINOUS SPIRAL GALAXIES

    SciTech Connect (OSTI)

    Hunter, Deidre A.; Ashburn, Allison; Wright, Teresa [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Elmegreen, Bruce G. [IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States); Rubin, Vera C. [Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Józsa, Gyula I. G.; Struve, Christian [ASTRON (Netherlands Organisation for Scientific Research NWO), Oude Hoogeveensedijk 4, 7991-PD Dwingeloo (Netherlands)

    2013-10-01T23:59:59.000Z

    We examined star formation in two very luminous (M{sub V} = –22 to –23) Sc-type spiral galaxies, NGC 801 and UGC 2885, using ultra-deep H? images. We combine these H? images with UBV and Two-Micron All-Sky Survey JHK images and H I maps to explore the star formation characteristics of disk galaxies at high luminosity. H? traces star formation in these galaxies to 4-6 disk scale lengths, but the lack of detection of H? further out is likely due to the loss of Lyman continuum photons. Considering gravitational instabilities alone, we find that the gas and stars in the outer regions are marginally stable in an average sense, but considering dissipative gas and radial and azimuthal forcing, the outer regions are marginally unstable to forming spiral arms. Star formation is taking place in spiral arms, which are regions of locally higher gas densities. Furthermore, we have traced smooth exponential stellar disks over four magnitudes in V-band surface brightness and 4-6 disk scale lengths, in spite of a highly variable gravitational instability parameter. Thus, gravitational instability thresholds do not seem relevant to the stellar disk. One possibility for creating an exponential disk is that the molecular cloud densities and star formation rates have exponential profiles and this fact forces the stellar disk to build up such a profile. Another possibility is that the stellar disk is continuously adjusted to an exponential shape regardless of the star formation profile, for example, through global dynamical processes that scatter stars. However, such scattering processes are only known to operate in spiral systems, in which case they cannot explain the same dilemma of smooth exponential disks observed in dwarf irregular galaxies.

  13. A plausible (overlooked) super-luminous supernova in the Sloan digital sky survey stripe 82 data

    SciTech Connect (OSTI)

    Kostrzewa-Rutkowska, Zuzanna; Koz?owski, Szymon; Wyrzykowski, ?ukasz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Djorgovski, S. George; Mahabal, Ashish A. [California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States); Glikman, Eilat [Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); Koposov, Sergey, E-mail: zkostrzewa@astrouw.edu.pl, E-mail: simkoz@astrouw.edu.pl, E-mail: wyrzykow@astrouw.edu.pl [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-12-01T23:59:59.000Z

    We present the discovery of a plausible super-luminous supernova (SLSN), found in the archival data of Sloan Digital Sky Survey (SDSS) Stripe 82, called PSN 000123+000504. The supernova (SN) peaked at m {sub g} < 19.4 mag in the second half of 2005 September, but was missed by the real-time SN hunt. The observed part of the light curve (17 epochs) showed that the rise to the maximum took over 30 days, while the decline time lasted at least 70 days (observed frame), closely resembling other SLSNe of SN 2007bi type. The spectrum of the host galaxy reveals a redshift of z = 0.281 and the distance modulus of ? = 40.77 mag. Combining this information with the SDSS photometry, we found the host galaxy to be an LMC-like irregular dwarf galaxy with an absolute magnitude of M{sub B} = –18.2 ± 0.2 mag and an oxygen abundance of 12+log?[O/H]=8.3±0.2; hence, the SN peaked at M {sub g} < –21.3 mag. Our SLSN follows the relation for the most energetic/super-luminous SNe exploding in low-metallicity environments, but we found no clear evidence for SLSNe to explode in low-luminosity (dwarf) galaxies only. The available information on the PSN 000123+000504 light curve suggests the magnetar-powered model as a likely scenario of this event. This SLSN is a new addition to a quickly growing family of super-luminous SNe.

  14. The Exceptionally Luminous Type II-L SN 2008es

    E-Print Network [OSTI]

    A. A. Miller; R. Chornock; D. A. Perley; M. Ganeshalingam; W. Li; N. R. Butler; J. S. Bloom; N. Smith; M. Modjaz; D. Poznanski; A. V. Filippenko; C. V. Griffith; J. H. Shiode; J. M. Silverman

    2008-09-03T23:59:59.000Z

    We report on our early photometric and spectroscopic observations of the extremely luminous Type II supernova (SN) 2008es. With an observed peak optical magnitude of m_V = 17.8 and at a redshift z = 0.213, SN 2008es had a peak absolute magnitude of M_V = -22.3, making it the second most luminous SN ever observed. The photometric evolution of SN 2008es exhibits a fast decline rate (~0.042 mag d^-1), similar to the extremely luminous Type II-L SN 2005ap. We show that SN 2008es spectroscopically resembles the luminous Type II-L SN 1979C. Although the spectra of SN 2008es lack the narrow and intermediate-width line emission typically associated with the interaction of a SN with the circumstellar medium of its progenitor star, we argue that the extreme luminosity of SN 2008es is powered via strong interaction with a dense, optically thick circumstellar medium. The integrated bolometric luminosity of SN 2008es yields a total radiated energy at ultraviolet and optical wavelengths of >10^51 ergs. Finally, we examine the apparently anomalous rate at which the Texas Supernova Search has discovered rare kinds of supernovae, including the five most luminous supernovae observed to date, and find that their results are consistent with those of other modern SN searches.

  15. Relativistic Radiative Flow in a Luminous Disk II

    E-Print Network [OSTI]

    Jun Fukue; Chizuru Akizuki

    2007-11-03T23:59:59.000Z

    Radiatively-driven transfer flow perpendicular to a luminous disk is examined in the relativistic regime of $(v/c)^2$, taking into account the gravity of the central object. The flow is assumed to be vertical, and the gas pressure as well as the magnetic field are ignored. Using a velocity-dependent variable Eddington factor, we can solve the rigorous equations of the relativistic radiative flow accelerated up to the {\\it relativistic} speed. For sufficiently luminous cases, the flow resembles the case without gravity. For less-luminous or small initial radius cases, however, the flow velocity decreases due to gravity. Application to a supercritical accretion disk with mass loss is briefly discussed.

  16. The Formation of Primordial Luminous Objects

    SciTech Connect (OSTI)

    Ripamonti, Emanuele; /Kapteyn Astron. Inst., Groningen; Abel, Tom; /KIPAC, Menlo Park

    2005-08-04T23:59:59.000Z

    The scientific belief that the universe evolves in time is one of the legacies of the theory of the Big Bang. The concept that the universe has an history started to attract the interest of cosmologists soon after the first formulation of the theory: already Gamow (1948; 1949) investigated how and when galaxies could have been formed in the context of the expanding Universe. However, the specific topic of the formation (and of the fate) of the first objects dates to two decades later, when no objects with metallicities as low as those predicted by primordial nucleosynthesis (Z {approx}< 10{sup -10} {approx} 10{sup -8}Z{sub {circle_dot}}) were found. Such concerns were addressed in two seminal papers by Peebles & Dicke (1968; hereafter PD68) and by Doroshkevich, Zel'Dovich & Novikov (1967; hereafter DZN67), introducing the idea that some objects could have formed before the stars we presently observe. (1) Both PD68 and DZN67 suggest a mass of {approx} 10{sup 5} M{sub {circle_dot}} for the first generation of bound systems, based on the considerations on the cosmological Jeans length (Gamow 1948; Peebles 1965) and the possible shape of the power spectrum. (2) They point out the role of thermal instabilities in the formation of the proto-galactic bound object, and of the cooling of the gas inside it; in particular, PD68 introduces H{sub 2} cooling and chemistry in the calculations about the contraction of the gas. (3) Even if they do not specifically address the occurrence of fragmentation, these papers make two very different assumptions: PD68 assumes that the gas will fragment into ''normal'' stars to form globular clusters, while DZN67 assumes that fragmentation does not occur, and that a single ''super-star'' forms. (4) Finally, some feedback effects as considered (e.g. Peebles & Dicke considered the effects of supernovae). Today most of the research focuses on the issues when fragmentation may occur, what objects are formed and how they influence subsequent structure formation. In these notes we will leave the discussion of feedback to lecture notes by Ferrara & Salvaterra and by Madau & Haardt in this same book and focus only on the aspects of the formation of the first objects. The advent of cosmological numerical hydrodynamics in particular allow a fresh new look at these questions. Hence, these notes will touch on aspects of theoretical cosmology to chemistry, computer science, hydrodynamics and atomic physics. For further reading and more references on the subject we refer the reader to other relevant reviews such as Barkana & Loeb 2001, and more recently Ciardi & Ferrara 2004, Glover 2004 and Bromm & Larson 2004. In these notes, we try to give a brief introduction to only the most relevant aspects. We will start with a brief overview of the relevant cosmological concepts in section 2, followed by a discussion of the properties of primordial material (with particular emphasis to its cooling and its chemistry) in section 3. We will then review the technique and the results of numerical simulations in sections 4 and 5: the former will deal with detailed 3D simulations of the formation of gaseous clouds which are likely to transform into luminous objects, while the latter will examine results (mostly from 1D codes) about the modalities of such transformation. Finally, in section 6 we will critically discuss the results of the previous sections, examining their consequences and comparing them to our present knowledge of the universe.

  17. WS1: one more new Galactic bona fide luminous blue variable

    E-Print Network [OSTI]

    Kniazev, A Y; Berdnikov, L N

    2015-01-01T23:59:59.000Z

    In this Letter, we report the results of spectroscopic and photometric monitoring of the candidate luminous blue variable (LBV) WS1, which was discovered in 2011 through the detection of a mid-infrared circular shell and follow-up optical spectroscopy of its central star. Our monitoring showed that WS1 brightened in the B, V and I bands by more than 1 mag during the last three years, while its spectrum revealed dramatic changes during the same time period, indicating that the star became much cooler. The light curve of WS1 demonstrates that the brightness of this star has reached maximum in 2013 December and then starts to decline. These findings unambiguously proved the LBV nature of WS1 and added one more member to the class of Galactic bona fide LBVs, bringing their number to sixteen (an updated census of these objects is provided).

  18. LUMINOUS AND VARIABLE STARS IN M31 AND M33. I. THE WARM HYPERGIANTS AND POST-RED SUPERGIANT EVOLUTION

    SciTech Connect (OSTI)

    Humphreys, Roberta M.; Davidson, Kris; Grammer, Skyler; Kneeland, Nathan [Minnesota Institute for Astrophysics, 116 Church Street SE, University of Minnesota, Minneapolis, MN 55455 (United States); Martin, John C. [University of Illinois, Springfield, IL (United States); Weis, Kerstin; Burggraf, Birgitta, E-mail: roberta@umn.edu [Astronomical Institute, Ruhr-Universitaet Bochum (Germany)

    2013-08-10T23:59:59.000Z

    The progenitors of Type IIP supernovae (SNe) have an apparent upper limit to their initial masses of about 20 M{sub Sun }, suggesting that the most massive red supergiants evolve to warmer temperatures before their terminal explosion. But very few post-red supergiants are known. We have identified a small group of luminous stars in M31 and M33 that are candidates for post-red supergiant evolution. These stars have A-F-type supergiant absorption line spectra and strong hydrogen emission. Their spectra are also distinguished by the Ca II triplet and [Ca II] doublet in emission formed in a low-density circumstellar environment. They all have significant near- and mid-infrared excess radiation due to free-free emission and thermal emission from dust. We estimate the amount of mass they have shed and discuss their wind parameters and mass loss rates, which range from a few Multiplication-Sign 10{sup -6} to 10{sup -4} M{sub Sun} yr{sup -1}. On an H-R diagram, these stars will overlap the region of the luminous blue variables (LBVs) at maximum light; however, the warm hypergiants are not LBVs. Their non-spherical winds are not optically thick, and they have not exhibited any significant variability. We suggest, however, that the warm hypergiants may be the progenitors of the ''less luminous'' LBVs such as R71 and even SN1987A.

  19. Theoretical aspects of underwater photography. I. Graphical-numerical calculation of the luminance field about a submerged point source

    E-Print Network [OSTI]

    Preisendorfer, Rudolph W

    1959-01-01T23:59:59.000Z

    CALCULATION OF THE LUMINANCE FIELD ABOUT A SUBMERGE) POINTin order that the field luminance about the given pointOr TH3 . ^l? I.MARY LUMINANCE FIELD ABOUT A SUBi.IERGSD

  20. On the maximum value of the cosmic abundance of oxygen and the oxygen yield

    E-Print Network [OSTI]

    L. S. Pilyugin; T. X. Thuan; J. M. Vilchez

    2007-01-11T23:59:59.000Z

    We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centers of the most luminous galaxies, we have constructed the luminosity - central metallicity diagram for spiral galaxies, based on a large compilation of existing data on oxygen abundances of HII regions in spiral galaxies. We found that this diagram shows a plateau at high luminosities (-22.3 oxygen abundance 12+log(O/H) ~ 8.87. This provides strong evidence that the oxygen abundance in the centers of the most luminous metal-rich galaxies reaches the maximum attainable value of oxygen abundance. Since some fraction of the oxygen (about 0.08 dex) is expected to be locked into dust grains, the maximum value of the true gas+dust oxygen abundance in spiral galaxies is 12+log(O/H) ~ 8.95. This value is a factor of ~ 2 higher than the recently estimated solar value. Based on the derived maximum oxygen abundance in galaxies, we found the oxygen yield to be about 0.0035, depending on the fraction of oxygen incorporated into dust grains.

  1. Constraint on super-luminal neutrinos from vacuum Cerenkov processes

    E-Print Network [OSTI]

    Subhendra Mohanty; Soumya Rao

    2011-12-16T23:59:59.000Z

    We examine the Cerenkov-like emission of $e^+ e^-$ from muon super-luminal muon neutrinos assuming a quadratic energy dependence of the neutrino velocity arising from Lorentz violating interactions. We find that with the OPERA result for the neutrino-photon velocity difference, the decay length for the process $\

  2. Achieve maximum application availability and

    E-Print Network [OSTI]

    Bernstein, Phil

    Highlights Achieve maximum application availability and data protection using SQL Server AlwaysOn and other high availability features Reduce planned downtime significantly with SQL Server on Windows and management of high availability and disaster recovery using integrated tools Achieve maximum application

  3. Visual Comfort Analysis of Innovative Interior and Exterior Shading Systems for Commercial Buildings using High Resolution Luminance Images

    E-Print Network [OSTI]

    Konis, Kyle

    2011-01-01T23:59:59.000Z

    accuracy of luminance maps under dynamic sky conditions. TheSummary of luminance values during clear sky conditions forluminance maps versus a shielded illuminance sensor under dynamic sky

  4. Duration expansion at low luminance levels Cognitive, Perceptual and Brain Sciences,

    E-Print Network [OSTI]

    Johnston, Alan

    Duration expansion at low luminance levels Cognitive, Perceptual and Brain Sciences, Division reversal as we decreased the luminance level, indicating a lengthening of the temporal impulse response. We then measured perceived duration at these luminance levels (0.75, 3, and 50 cd/m2 ) after matching for apparent

  5. Rapid Communication Orientation selectivity in luminance and color vision assessed using

    E-Print Network [OSTI]

    Mullen, Kathy T.

    Rapid Communication Orientation selectivity in luminance and color vision assessed using 2-d band in color and luminance vision using an external noise paradigm. Stimuli were spatiotem- poral patches of 2D with the stimuli orientation bandwidths that is similar for both color and luminance contrasts. This dependence

  6. Cortical visual processing is temporally dispersed by luminance in human subjects

    E-Print Network [OSTI]

    Cortical visual processing is temporally dispersed by luminance in human subjects Thomas Kammer Abstract Increasing the intensity of a stimulus such as luminance results in faster processing the luminance of the spots from 1 to 1000 cd/m2 . The data show that processing time as a function of intensity

  7. Interactions between chromatic-and luminance-contrast-sensitive stereopsis mechanisms

    E-Print Network [OSTI]

    Kingdom, Frederick A. A.

    Interactions between chromatic- and luminance-contrast-sensitive stereopsis mechanisms David R-order stereopsis mechanisms, one sensitive to chromatic contrast and the other sensitive to luminance contrast of chromatic and luminance contrast which could be correlated or anti-correlated between the eyes. Stereoscopic

  8. The effect of luminance on simulated driving speed Sarah J. Pritchard and Stephen T. Hammett

    E-Print Network [OSTI]

    Sheldon, Nathan D.

    The effect of luminance on simulated driving speed Sarah J. Pritchard and Stephen T. Hammett§ Dept such as contrast, luminance and adaptation duration. It has been suggested that such changes in perceived speed may influence driving behaviour. In order to evaluate the effect of luminance on driving speed we have measured

  9. Perception, 1990, volume 19, pages 79-101 The standard deviation of luminance as a metric

    E-Print Network [OSTI]

    Kingdom, Frederick A. A.

    Perception, 1990, volume 19, pages 79-101 The standard deviation of luminance as a metric with periodic luminance profiles, such as gratings, but is not suitable for images consisting of isolated the standard deviation (SD) of the luminances (equivalent to the root mean square, RMS, of the amplitudes) has

  10. Characterizing motion contour detection mechanisms and equivalent mechanisms in the luminance domain

    E-Print Network [OSTI]

    Zanker, Johannes M.

    Characterizing motion contour detection mechanisms and equivalent mechanisms in the luminance with sparsely defined luminance Gabor patterns and found similar results, but only at low sampling densities. The nature of the information and the strength of the signal influence the properties of luminance contour

  11. GENERALIZED ANALYTIC STELLAR STABILITY CRITERIA WITH APPLICATIONS TO LUMINOUS STELLAR ENVELOPES

    E-Print Network [OSTI]

    GENERALIZED ANALYTIC STELLAR STABILITY CRITERIA WITH APPLICATIONS TO LUMINOUS STELLAR ENVELOPES to the outer envelopes of luminous blue variables (LBVs). The acceleration of stellar-wind mass loss has instabilities in luminous blue variables (LBVs), where the acceleration of mass loss becomes significant, even

  12. Title of Dissertation: Outflows in Infrared-Luminous Galaxies: Absorption-Line Spectroscopy

    E-Print Network [OSTI]

    Gruner, Daniel S.

    Abstract Title of Dissertation: Outflows in Infrared-Luminous Galaxies: Absorption performed a survey of over 100 infrared-luminous galaxies in or- der to address the exact frequency galaxies, and their proper- ties in the most luminous starburst and active galaxies. Most of our sample

  13. TURBULENT PRESSURE IN THE ENVELOPES OF YELLOW HYPERGIANTS AND LUMINOUS BLUE VARIABLES

    E-Print Network [OSTI]

    TURBULENT PRESSURE IN THE ENVELOPES OF YELLOW HYPERGIANTS AND LUMINOUS BLUE VARIABLES Richard B turbulent pressure) affects the structure and stability of luminous post­red-supergiant stars is critically and generates energetic shocks or if convection is unable to transport all of the super-Eddington luminous flux

  14. Poynting's theorem and luminal total energy transport in passive dielectric media S. Glasgow,1

    E-Print Network [OSTI]

    Hart, Gus

    Poynting's theorem and luminal total energy transport in passive dielectric media S. Glasgow,1 M to a virtual, ``instantaneous'' field spectrum, 2 that a causal, passive medium supports only a luminal front velocity, 3 that the spatial ``center-of-mass'' motion of the total dynamical energy is also always luminal

  15. Vision Research 39 (1999) 559568 On the relationship between the spatial channels for luminance

    E-Print Network [OSTI]

    Kingdom, Frederick A. A.

    1999-01-01T23:59:59.000Z

    Vision Research 39 (1999) 559­568 On the relationship between the spatial channels for luminance the relationship between the spatial channels for luminance and shape-from-stereo-disparity processing we measured of a field of Gabor micropatterns of differing luminance spatial frequency. We first examine the effects

  16. MAGNETIC INFLUENCE ON THE STABILITY OF LUMINOUS STELLAR ENVELOPES Richard B. Stothers

    E-Print Network [OSTI]

    MAGNETIC INFLUENCE ON THE STABILITY OF LUMINOUS STELLAR ENVELOPES Richard B. Stothers NASA Goddard February 11 ABSTRACT Turbulence in the convective outer envelope of a luminous post­main-sequence star the field lines. Otherwise, the bulk of the outer envelopes in stars such as yellow hypergiants, luminous

  17. Transient luminous events above two mesoscale convective systems: Charge moment change analysis

    E-Print Network [OSTI]

    Rutledge, Steven

    Transient luminous events above two mesoscale convective systems: Charge moment change analysis that were parents of transient luminous events (TLEs; mainly sprites) over two different storms: 9 May (20. A. Rutledge, and D. R. MacGorman (2011), Transient luminous events above two mesoscale convective

  18. Behavioral/Systems/Cognitive Luminance-Evoked Inhibition in Primary Visual Cortex: A

    E-Print Network [OSTI]

    Behavioral/Systems/Cognitive Luminance-Evoked Inhibition in Primary Visual Cortex: A Transient Veto University Medical Center, Durham, North Carolina 27710 Large-scale changes in luminance are known to exert recording to explore the impact of luminance transients on the responses of orientation-selective neurons

  19. Competition between color and luminance for target selection in smooth pursuit and saccadic

    E-Print Network [OSTI]

    Carrasco, Marisa

    Competition between color and luminance for target selection in smooth pursuit and saccadic eye of color and luminance for smooth pursuit and saccadic eye movements was investigated using a target selection paradigm. In two experiments, stimuli were varied along the dimensions color and luminance

  20. Optical and Physicochemical Characterization of the Luminous Mucous Secreted by the Marine Worm Chaetopterus sp.

    E-Print Network [OSTI]

    Blair, Daniel

    Optical and Physicochemical Characterization of the Luminous Mucous Secreted by the Marine Worm and Physicochemical Characterization of the Luminous Mucous Secreted by the Marine Worm Chaetopterus sp mucus only. Here, we report the optical and physico- chemical properties of the luminous mucus. We show

  1. Introduction Luminance and Chrominance High Frequency Content References Smoke Detection in Stationary Video Using

    E-Print Network [OSTI]

    Knaust, Helmut

    Introduction Luminance and Chrominance High Frequency Content References Smoke Detection at El Paso El Paso TX 79968-0514 hknaust@utep.edu January 6, 2012 #12;Introduction Luminance and Chrominance High Frequency Content References The Problem The Problem: VIDEO: #12;Introduction Luminance

  2. Effect of the luminance signal on adaptation-based time compression

    E-Print Network [OSTI]

    Johnston, Alan

    Effect of the luminance signal on adaptation-based time compression Cognitive, Perceptual and Brain with modality-specific sensory components. Here, we examine the effect of the luminance signal on these adaptation-based temporal distortions. Our results show that the luminance signal is crucial to generate

  3. Vision Research 41 (2001) 375383 The role of chromatic contrast and luminance polarity in

    E-Print Network [OSTI]

    Kingdom, Frederick A. A.

    2001-01-01T23:59:59.000Z

    Vision Research 41 (2001) 375­383 The role of chromatic contrast and luminance polarity and distractors differ in particular combinations of colour and luminance polarity. For flat-plane targets, stereo-thresholds were found to be lower with a target-distractor colour/luminance difference, but only when

  4. Vision Research 39 (1999) 721731 The spatial tuning of color and luminance peripheral vision

    E-Print Network [OSTI]

    Mullen, Kathy T.

    1999-01-01T23:59:59.000Z

    Vision Research 39 (1999) 721­731 The spatial tuning of color and luminance peripheral vision red-green chromatic and luminance mechanisms at four locations in the nasal visual field (0, 10, 20-frequency looking for our stimuli. Detection thresholds were measured for luminance or isoluminant red

  5. Paclitaxel coating of the luminal surface of hemodialysis grafts with effective suppression of

    E-Print Network [OSTI]

    Park, Jong-Sang

    Paclitaxel coating of the luminal surface of hemodialysis grafts with effective suppression, we developed a method to coat the drug only on the luminal surface of the graft, with little loading only on the luminal surface of the graft without changing the physical properties. To determine its

  6. Recent advances in theory of transient luminous events Victor P. Pasko1

    E-Print Network [OSTI]

    Pasko, Victor

    Click Here for Full Article Recent advances in theory of transient luminous events Victor P. Pasko1 features of transient luminous events termed sprites, blue jets, and gigantic jets. The primary emphasis), Recent advances in theory of transient luminous events, J. Geophys. Res., 115, A00E35, doi:10.1029/2009JA

  7. Vision Research 40 (2000) 16951709 Texture luminance judgments are approximately veridical

    E-Print Network [OSTI]

    California at Irvine, University of

    2000-01-01T23:59:59.000Z

    Vision Research 40 (2000) 1695­1709 Texture luminance judgments are approximately veridical Jong. Specifically, we address the following question: how do different luminances influence the perceived total luminance of a composite image? We investigate this question using a paradigm in which the observer attempts

  8. Original article Restricted maximum likelihood

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Original article Restricted maximum likelihood estimation of covariances in sparse linear models on the simplex algorithm of Nelder and Mead [40]. Kovac [29] made modifications that turned it into a stable

  9. INFRARED CLASSIFICATION AND LUMINOSITIES FOR DUSTY ACTIVE GALACTIC NUCLEI AND THE MOST LUMINOUS QUASARS

    SciTech Connect (OSTI)

    Weedman, Daniel; Sargsyan, Lusine; Houck, James; Barry, Donald [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Lebouteiller, Vianney, E-mail: dweedman@isc.astro.cornell.edu [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, DAPNIA/Service d'Astrophysique, Saclay, F-91191 Gif-sur-Yvette Cedex (France)

    2012-12-20T23:59:59.000Z

    Mid-infrared spectroscopic measurements from the Infrared Spectrometer (IRS) on Spitzer are given for 125 hard X-ray active galactic nuclei (AGNs; 14-195 keV) from the Swift Burst Alert Telescope (BAT) sample and for 32 AGNs with black hole masses (BHMs) from reverberation mapping. The 9.7 {mu}m silicate feature in emission or absorption defines an infrared AGN classification describing whether AGNs are observed through dust clouds, indicating that 55% of the BAT AGNs are observed through dust. The mid-infrared dust continuum luminosity is shown to be an excellent indicator of intrinsic AGN luminosity, scaling closely with the hard X-ray luminosity, log {nu}L{sub {nu}}(7.8 {mu}m)/L(X) = -0.31 {+-} 0.35, and independent of classification determined from silicate emission or absorption. Dust luminosity scales closely with BHM, log {nu}L{sub {nu}}(7.8 {mu}m) = (37.2 {+-} 0.5) + 0.87 log BHM for luminosity in erg s{sup -1} and BHM in M{sub Sun }. The 100 most luminous type 1 quasars as measured in {nu}L{sub {nu}}(7.8 {mu}m) are found by comparing Sloan Digital Sky Survey (SDSS) optically discovered quasars with photometry at 22 {mu}m from the Wide-Field Infrared Survey Explorer (WISE), scaled to rest frame 7.8 {mu}m using an empirical template determined from IRS spectra. The most luminous SDSS/WISE quasars have the same maximum infrared luminosities for all 1.5 < z < 5, reaching total infrared luminosity L{sub IR} = 10{sup 14.4} L{sub Sun }. Comparing with dust-obscured galaxies from Spitzer and WISE surveys, we find no evidence of hyperluminous obscured quasars whose maximum infrared luminosities exceed the maximum infrared luminosities of optically discovered quasars. Bolometric luminosities L{sub bol} estimated from rest-frame optical or ultraviolet luminosities are compared to L{sub IR}. For the local AGN, the median log L{sub IR}/L{sub bol} = -0.35, consistent with a covering factor of 45% for the absorbing dust clouds. For the SDSS/WISE quasars, the median log L{sub IR}/L{sub bol} = 0.1, with extremes indicating that ultraviolet-derived L{sub bol} can be seriously underestimated even for type 1 quasars.

  10. UNUSUAL LONG AND LUMINOUS OPTICAL TRANSIENT IN THE SUBARU DEEP FIELD

    SciTech Connect (OSTI)

    Urata, Yuji; Tsai, Patrick P. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106, Taiwan (China); Morokuma, Tomoki; Motohara, Kentaro [Institute of Astronomy, Graduate School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Yasuda, Naoki [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8568 (Japan); Tanaka, Masaomi; Hayashi, Masao; Kashikawa, Nobunari [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Ly, Chun [Space Telescope Science Institute, Baltimore, MD (United States); Malkan, Matthew A., E-mail: urata@astro.ncu.edu.tw [Department of Physics and Astronomy, UCLA, Box 951547, Los Angeles, CA (United States)

    2012-11-20T23:59:59.000Z

    We present observations of SDF-05M05, an unusual optical transient discovered in the Subaru Deep Field (SDF). The duration of the transient is > {approx} 800 days in the observer frame, and the maximum brightness during observation reached approximately 23 mag in the i' and z' bands. The faint host galaxy is clearly identified in all five optical bands of the deep SDF images. The photometric redshift of the host yields z {approx} 0.6 and the corresponding absolute magnitude at maximum is {approx} - 20. This implies that this event shone with an absolute magnitude brighter than -19 mag for approximately 300 days in the rest frame, which is significantly longer than a typical supernova and ultraluminous supernova. The total radiated energy during our observation was 1 Multiplication-Sign 10{sup 51} erg. The light curves and color evolution are marginally consistent with some luminous IIn supernovae. We suggest that the transient may be a unique and peculiar supernova at intermediate redshift.

  11. A LUMINOUS AND FAST-EXPANDING TYPE Ib SUPERNOVA SN 2012au

    SciTech Connect (OSTI)

    Takaki, Katsutoshi; Fukazawa, Yasushi; Itoh, Ryosuke; Ueno, Issei; Ui, Takahiro; Urano, Takeshi [Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawabata, Koji S.; Akitaya, Hiroshi; Moritani, Yuki; Ohsugi, Takashi; Uemura, Makoto; Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yamanaka, Masayuki [Kwasan Observatory, Kyoto University, Ohmine-cho Kita Kazan, Yamashina-ku, Kyoto 607-8471 (Japan); Maeda, Keiichi; Nomoto, Ken'ichi [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Tanaka, Masaomi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kinugasa, Kenzo [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, 462-2 Nobeyama, Minamimaki, Nagano 384-1305 (Japan); Sasada, Mahito, E-mail: takaki@hep01.hepl.hiroshima-u.ac.jp [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-08-01T23:59:59.000Z

    We present a set of photometric and spectroscopic observations of a bright Type Ib supernova SN 2012au from -6 days until {approx} + 150 days after maximum. The shape of its early R-band light curve is similar to that of an average Type Ib/c supernova. The peak absolute magnitude is M{sub R} = -18.7 {+-} 0.2 mag, which suggests that this supernova belongs to a very luminous group among Type Ib supernovae. The line velocity of He I {lambda}5876 is about 15,000 km s{sup -1} around maximum, which is much faster than that in a typical Type Ib supernova. From the quasi-bolometric peak luminosity of (6.7 {+-} 1.3) Multiplication-Sign 10{sup 42} erg s{sup -1}, we estimate the {sup 56}Ni mass produced during the explosion as {approx}0.30 M{sub Sun }. We also give a rough constraint to the ejecta mass 5-7 M{sub Sun} and the kinetic energy (7-18) Multiplication-Sign 10{sup 51} erg. We find a weak correlation between the peak absolute magnitude and He I velocity among Type Ib SNe. The similarities to SN 1998bw in the density structure inferred from the light-curve model as well as the large peak bolometric luminosity suggest that SN 2012au had properties similar to energetic Type Ic supernovae.

  12. Enigmatic sub-luminous accreting neutron stars in our Galaxy

    E-Print Network [OSTI]

    Rudy Wijnands

    2008-01-07T23:59:59.000Z

    During the last few years a class of enigmatic sub-luminous accreting neutron stars has been found in our Galaxy. They have peak X-ray luminosities (2-10 keV) of a few times 1E34 erg/s to a few times 1E35 erg/s, and both persistent and transient sources have been found. I present a short overview of our knowledge of these systems and what we can learn from them.

  13. Failure of signed chromatic apparent motion with luminance masking Tatsuya Yoshizawa, Kathy T. Mullen, Curtis L. Baker Jr. *

    E-Print Network [OSTI]

    Mullen, Kathy T.

    Failure of signed chromatic apparent motion with luminance masking Tatsuya Yoshizawa, Kathy T measured in the presence of a dynamic luminance masking noise. Increasing the luminance noise contrast­green chromatic motion is derived from a luminance- based signal, rather than a genuinely chromatic motion

  14. Positron Excess, Luminous-Dark Matter Unification and Family Structure

    E-Print Network [OSTI]

    Paul H. Frampton; Pham Q. Hung

    2009-04-16T23:59:59.000Z

    It is commonly assumed that dark matter may be composed of one or at most a few elementary particles. PAMELA data present a window of opportunity into a possible relationship between luminous and dark matter. Along with ATIC data the two positron excesses are interpreted as a reflection of dark matter family structure. In a unified model it is predicted that at least a third enhancement might show up at a different energy. The strength of the enhancements however depends on interfamily mixing angles.

  15. Maximum likelihood estimation for cooperative sequential adsorption

    E-Print Network [OSTI]

    Burton, Geoffrey R.

    Maximum likelihood estimation for cooperative sequential adsorption Mathew D. Penrose and Vadim;Maximum likelihood estimation for cooperative sequential adsorption M.D. Penrose, Department of the region. Keywords: cooperative sequential adsorption, space-time point pro- cess, maximum likelihood

  16. Estimating a mixed strategy employing maximum entropy

    E-Print Network [OSTI]

    Golan, Amos; Karp, Larry; Perloff, Jeffrey M.

    1996-01-01T23:59:59.000Z

    MIXED STRATEGY EMPLOYING MAXIMUM ENTROPY by Amos Golan LarryMixed Strategy Employing Maximum Entropy Amos Golan Larry S.Abstract Generalized maximum entropy may be used to estimate

  17. Boiler Maximum Achievable Control Technology (MACT) Technical...

    Energy Savers [EERE]

    Boiler Maximum Achievable Control Technology (MACT) Technical Assistance - Fact Sheet, April 2015 Boiler Maximum Achievable Control Technology (MACT) Technical Assistance - Fact...

  18. Companions around the nearest luminous galaxies: segregation and selection effects

    E-Print Network [OSTI]

    Karachentsev, I D

    2015-01-01T23:59:59.000Z

    Using the "Updated Nearby Galaxy Catalog", we consider different properties of companion galaxies around luminous hosts in the Local Volume. The data on stellar masses, linear diameters,surface brightnesses, HI-richness, specific star formation rate (sSFR), and morphological types are discussed for members of the nearest groups, including the Milky Way and M 31 groups, as a function of their separation from the hosts. Companion galaxies in groups tend to have lower stellar masses, smaller linear diameters and fainter mean surface brightnesses as the distance to their host decreases. The hydrogen-to-stellar mass ratio of the companions increases with their linear projected separation from the dominant luminous galaxy. This tendency is more expressed around the bulge-dominated hosts. While linear separation of the companions decreases, their mean sSFR becomes lower, accompanied with the increasing sSFR scatter. Typical linear projected separation of dSphs around the bulge-dominated hosts, 350 kpc, is substantia...

  19. The Luminous Starburst Ring in NGC 7771: Sequential Star Formation?

    E-Print Network [OSTI]

    Denise A. Smith; Terry Herter; Martha P. Haynes; Susan G. Neff

    1998-08-28T23:59:59.000Z

    Only two of the twenty highly luminous starburst galaxies analyzed by Smith et al. exhibit circumnuclear rings of star formation. These galaxies provide a link between 10^11 L_sun systems and classical, less-luminous ringed systems. We report the discovery of a near-infrared counterpart to the nuclear ring of radio emission in NGC 7771. A displacement between the ~10 radio bright clumps and the ~10 near-infrared bright clumps indicates the presence of multiple generations of star formation. The estimated thermal emission from each radio source is equivalent to that of ~35000 O6 stars. Each near-infrared bright knot contains ~5000 red supergiants, on average. The stellar mass of each knot is estimated to be ~10^7 M_sun. The implied time-averaged star formation rate is \\~40 M_sun per yr. Several similarities are found between the properties of this system and other ringed and non-ringed starbursts. Morphological differences between NGC 7771 and the starburst + Seyfert 1 galaxy NGC 7469 suggest that NGC 7771 may not be old enough to fuel an AGN, or may not be capable of fueling an AGN. Alternatively, the differences may be unrelated to the presence or absence of an AGN and may simply reflect the possibility that star formation in rings is episodic.

  20. Long-term spectroscopic monitoring of the Luminous Blue Variable HD160529

    E-Print Network [OSTI]

    Otmar Stahl; Thomas Gaeng; Chris Sterken; Andreas Kaufer; Thomas Rivinius; Thomas Szeifert; Bernhard Wolf

    2002-12-20T23:59:59.000Z

    We have spectroscopically monitored the galactic Luminous Blue Variable HD 160529 and obtained an extensive high-resolution data set that covers the years 1991 to 2002. During this period, the star evolved from an extended photometric minimum phase towards a new visual maximum. In several observing seasons, we covered up to four months with almost daily spectra. Our spectra typically cover most of the visual spectral range with a high spectral resolution (about 20,000 or more). This allows us to investigate the variability in many lines and on many time scales from days to years. We find a correlation between the photospheric HeI lines and the brightness of the star, both on a time scale of months and on a time scale of years. The short-term variations are smaller and do not follow the long-term trend, strongly suggesting different physical mechanisms. Metal lines also show both short-term and long-term variations in strength and also a long-term trend in radial velocity. Most of the line-profile variations can be attributed to changing strengths of lines. Propagating features in the line profiles are rarely observed. We find that the mass-loss rate of HD 160529 is almost independent of temperature, i.e. visual brightness.

  1. Keck High-Resolution Spectroscopy of Outflows in Infrared Luminous Galaxies

    E-Print Network [OSTI]

    David S. Rupke; Sylvain Veilleux

    2005-09-05T23:59:59.000Z

    Several recent studies have determined that large quantities of neutral gas are outflowing from the nuclei of almost all infrared-luminous galaxies. These measurements show that winds in infrared-luminous galaxies play a significant role in the evolution of galaxies and the intergalactic medium at redshifts z > 1, when infrared-luminous galaxies dominated the star formation rate of the universe. These conclusions rely on moderate resolution spectra (FWHM > 65 km/s) of the NaI D absorption line and the assumption that there are no unresolved, saturated velocity components. For the first time, we present high resolution spectra (FWHM = 13 km/s) of massive, infrared-luminous galaxies. The five galaxies in our sample are known to host outflows on the basis of previous observations. With the present observations, all NaI D velocity components are resolved with tau(NaI D1 5896 A) luminous galaxies have been measured correctly by previous studies.

  2. Black hole feedback in the luminous quasar PDS 456

    E-Print Network [OSTI]

    Nardini, E; Gofford, J; Harrison, F A; Risaliti, G; Braito, V; Costa, M T; Matzeu, G A; Walton, D J; Behar, E; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Matt, G; Miller, J M; O'Brien, P T; Stern, D; Turner, T J; Ward, M J

    2015-01-01T23:59:59.000Z

    The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband X-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10^46 ergs per second is enough to provide the feedback required by models of black hole and host galaxy co-evolution.

  3. Cosmological Constraints from the SDSS Luminous Red Galaxies

    E-Print Network [OSTI]

    M Tegmark; D Eisenstein; M Strauss; D Weinberg; M Blanton; J Frieman; M Fukugita; J Gunn; A Hamilton; G Knapp; R Nichol; J Ostriker; N Padmanabhan; W Percival; D Schlegel; D Schneider; R Scoccimarro; U Seljak; H Seo; M Swanson; A Szalay; M Vogeley; J Yoo; I Zehavi; K Abazajian; S Anderson; J Annis; N Bahcall; B Bassett; A Berlind; J Brinkmann; T Budavari; F Castander; A Connolly; I Csabai; M Doi; D Finkbeiner; B Gillespie; K Glazebrook; G Hennessy; D Hogg; Z Ivezic; B Jain; D Johnston; S Kent; D Lamb; B Lee; H Lin; J Loveday; R Lupton; J Munn; K Pan; C Park; J Peoples; J Pier; A Pope; M Richmond; C Rockosi; R Scranton; R Sheth; A Stebbins; C Stoughton; I Szapudi; D Tucker; D Vanden Berk; B Yanny; D York

    2006-10-30T23:59:59.000Z

    We measure the large-scale real-space power spectrum P(k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance measurements in 20 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.01h/Mpc 0.1h/Mpc and associated nonlinear complications, yet agree well with more aggressive published analyses where nonlinear modeling is crucial.

  4. Peaked Encoding of Relative Luminance in Macaque Areas V1 and V2 Xinmiao Peng and David C. Van Essen

    E-Print Network [OSTI]

    Van Essen, David

    Peaked Encoding of Relative Luminance in Macaque Areas V1 and V2 Xinmiao Peng and David C. Van. Peaked encoding of relative luminance in macaque areas V1 and V2. J Neurophysiol 93: 1620­1632, 2005 the primate visual pathway neurons encode the relative luminance of objects (at a given light adaptation level

  5. Texture-orientation mechanisms pool colour and luminance contrast P.M. Pearson a,*, F.A.A. Kingdom b

    E-Print Network [OSTI]

    Kingdom, Frederick A. A.

    Texture-orientation mechanisms pool colour and luminance contrast P.M. Pearson a,*, F.A.A. Kingdom-sensitive mechanisms operate separately on, or pool, luminance and colour contrast information? We addressed comprised of gabor elements defined by either colour or luminance contrast. In both the uncrossed (all

  6. The S-cone contribution to luminance depends on the M-and L-cone adaptation levels: Silent surrounds?

    E-Print Network [OSTI]

    Ripamonti, Caterina

    The S-cone contribution to luminance depends on the M- and L-cone adaptation levels: Silent, UKAndrew Stockman Under dim background conditions, the S-cones make little or no contribution to luminance long-wavelength adaptation, a small but robust contribution to luminanceVas defined by heterochromatic

  7. Maximum entropy principal for transportation

    SciTech Connect (OSTI)

    Bilich, F. [University of Brasilia (Brazil); Da Silva, R. [National Research Council (Brazil)

    2008-11-06T23:59:59.000Z

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  8. Infrared colour properties of nearby radio-luminous galaxies

    E-Print Network [OSTI]

    Yang, Xiao-hong; Huang, Yan

    2015-01-01T23:59:59.000Z

    By combining the data of the Two Micron All Sky Survey (2MASS), the Wide Field Infrared Survey Explorer (WISE) and the Akari satellite, we study the infrared colour properties of a sample of 2712 nearby radio-luminous galaxies (RLGs). These RLGs are divided into radio-loud (RL) active galactic nuclei (AGNs), mainly occurring at redshifts of $0.05$ 3.0. We also analyse the MIR colours of RL AGNs divided into low- and high-excitation radio galaxies (LERGs and HERGs, respectively). The ([3.4]-[4.6])$-$([4.6]-[12]) diagram clearly shows separate distributions of LERGs and HERGs and a region of overlap, which suggests that LERGs and HERGs have different MIR properties. LERGs are responsible for the double-core distribution of RL AGNs on the ([3.4]-[4.6])$-$([4.6]-[12]) diagram. In addition, we also suggest 90$-$140$\\mu$m band spectral index $\\alpha(90,140)<-1.4$ as a criterion of selecting nearby active galaxies with non-thermal emissions at FIR wavelengths.

  9. Chemical composition and origin of nebulae around Luminous Blue Variables

    E-Print Network [OSTI]

    Lamers, Henny J G L M; Panagia, N; Smith, L J; Langer, N; Lamers, Henny J.G.L.M.; Nota, Antonella; Panagia, Nino; Smith, Linda J.; Langer, Norbert

    2001-01-01T23:59:59.000Z

    We use the analysis of the heavy element abundances (C, N, O, S) in circumstellar nebulae around Luminous Blue Variables to infer the evolutionary phase in which the material has been ejected. (1) We discuss the different effects that may have changed the gas composition of the nebula since it was ejected (2) We calculate the expected abundance changes at the stellar surface due to envelope convection in the red supergiant phase. If the observed LBV nebulae are ejected during the RSG phase, the abundances of the LBV nebulae require a significantly smaller amount of mass to be lost than assumed in evolutionary models. (3) We calculate the changes in the surface composition during the main sequence phase by rotation induced mixing. If the nebulae are ejected at the end of the MS-phase, the abundances in LBV nebulae are compatible with mixing times between 5 x 10^6 and 1 x 10^7 years. The existence of ON stars supports this scenario. (4) The predicted He/H ratio in the nebulae are significantly smaller than the ...

  10. The distance scale and Eddington efficiency of luminous quasars

    E-Print Network [OSTI]

    P. Teerikorpi

    2005-10-13T23:59:59.000Z

    The relation between the central mass and quasar luminosity (M_BH \\propto L^{\\alpha}FHWM^2) links a given Eddington ratio with a value of H_0, within a cosmology with fixed (\\Omega_m,\\Omega_{\\Lambda}). We point out that because the relation is calibrated at low z using distance independent reverberation mapping to get the BLR size, the derived M_BH interestingly does not depend on H_0, while L/L_Edd is sensitive to H_0, but rather robust to changes of \\Omega_{\\Lambda} in the standard flat model. This means, e.g., that enough of extragalactic objects radiating at the Eddington limit could be used to study the global Hubble constant in a new way, bypassing the local distance ladder. The method could become practical when systematic errors in derived M_BH are understood and objects with L /leq L_Edd can be independently identified. As an illustration, if we take a sample of tranquil very luminous quasars in the redshift range 0.5 < z < 1.6, and assume that they are radiating with L_bol \\leq L_Edd, then the usual numeric factors used for calculating M_BH and L_bol would lead to the result that the Hubble constant must be larger than 45 km/s/Mpc.

  11. Testing Cosmological Models with Type Ic Super Luminous Supernovae

    E-Print Network [OSTI]

    Wei, Jun-Jie; Melia, Fulvio

    2015-01-01T23:59:59.000Z

    The use of type Ic Super Luminous Supernovae (SLSN Ic) to examine the cosmological expansion introduces a new standard ruler with which to test theoretical models. The sample suitable for this kind of work now includes 11 SLSNe Ic, which have thus far been used solely in tests involving $\\Lambda$CDM. In this paper, we broaden the base of support for this new, important cosmic probe by using these observations to carry out a one-on-one comparison between the $R_{\\rm h}=ct$ and $\\Lambda$CDM cosmologies. We individually optimize the parameters in each cosmological model by minimizing the $\\chi^{2}$ statistic. We also carry out Monte Carlo simulations based on these current SLSN Ic measurements to estimate how large the sample would have to be in order to rule out either model at a $\\sim 99.7\\%$ confidence level. The currently available sample indicates a likelihood of $\\sim$$70-80\\%$ that the $R_{\\rm h}=ct$ Universe is the correct cosmology versus $\\sim$$20-30\\%$ for the standard model. These results are suggest...

  12. Numerical simulations of super-luminous supernovae of type IIn

    E-Print Network [OSTI]

    Dessart, Luc; Hillier, D John

    2015-01-01T23:59:59.000Z

    We present numerical simulations that include 1-D Eulerian multi-group radiation-hydrodynamics, 1-D non-LTE radiative transfer, and 2-D polarised radiative transfer for super-luminous interacting supernovae (SNe). Our reference model is a ~10Msun inner shell with 10^51erg ramming into a ~3Msun cold outer shell (the circumstellar-medium, or CSM) that extends from 10^15cm to 2x10^16cm and moves at 100km/s. We discuss the light curve evolution, which cannot be captured adequately with a grey approach. In these interactions, the shock-crossing time through the optically-thick CSM is much longer than the photon diffusion time. Radiation is thus continuously leaking from the shock through the CSM, in disagreement with the shell-shocked model that is often invoked. Our spectra redden with time, with a peak distribution in the near-UV during the first month gradually shifting to the optical range over the following year. Initially Balmer lines exhibit a narrow line core and the broad line wings that are characteristi...

  13. A LUMINOUS Be+WHITE DWARF SUPERSOFT SOURCE IN THE WING OF THE SMC: MAXI J0158-744

    SciTech Connect (OSTI)

    Li, K. L.; Kong, Albert K. H.; Lu, Ting-Ni [Institute of Astronomy and Department of Physics, National Tsing Hua University, Taiwan (China); Charles, P. A.; Bartlett, E. S.; Coe, M. J. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); McBride, V.; Rajoelimanana, A. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Udalski, A. [Warsaw University Observatory, Aleje Ujazdowskie 4, 00-478 Warsaw (Poland); Masetti, N. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129 Bologna (Italy); Franzen, Thomas [CSIRO Astronomy and Space Science, PO Box 76, Epping NSW 1710 (Australia)

    2012-12-20T23:59:59.000Z

    We present a multi-wavelength analysis of the very fast X-ray transient MAXI J0158-744, which was detected by MAXI/GSC on 2011 November 11. The subsequent exponential decline of the X-ray flux was followed with Swift observations, all of which revealed spectra with low temperatures ({approx}100 eV), indicating that MAXI J0158-744 is a new Supersoft Source (SSS). The Swift X-ray spectra near maximum show features around 0.8 keV that we interpret as possible absorption from O VIII and emission from O, Fe, and Ne lines. We obtained SAAO and ESO optical spectra of the counterpart early in the outburst and several weeks later. The early spectrum is dominated by strong Balmer and He I emission, together with weaker He II emission. The later spectrum reveals absorption features that indicate a B1/2IIIe spectral type, and all spectral features are at velocities consistent with the Small Magellanic Cloud. At this distance, it is a luminous SSS (>10{sup 37} erg s{sup -1}) but whose brief peak luminosity of >10{sup 39} erg s{sup -1} in the 2-4 keV band makes it the brightest SSS yet seen at ''hard'' X-rays. We propose that MAXI J0158-744 is a Be-WD binary, and the first example to possibly enter ULX territory. The brief hard X-ray flash could possibly be a result of the interaction of the ejected nova shell with the B star wind in which the white dwarf (WD) is embedded. This makes MAXI J0158-744 only the third Be/WD system in the Magellanic Clouds, but it is by far the most luminous. The properties of MAXI J0158-744 give weight to previous suggestions that SSS in nearby galaxies are associated with early-type stellar systems.

  14. IDENTIFYING LUMINOUS ACTIVE GALACTIC NUCLEI IN DEEP SURVEYS: REVISED IRAC SELECTION CRITERIA

    E-Print Network [OSTI]

    Donley, J. L.

    Spitzer/IRAC selection is a powerful tool for identifying luminous active galactic nuclei (AGNs). For deep IRAC data, however, the AGN selection wedges currently in use are heavily contaminated by star-forming galaxies, ...

  15. Overdensities of SMGs around WISE-selected, ultra-luminous, high-redshift galaxies

    E-Print Network [OSTI]

    Jones, Suzy F

    2015-01-01T23:59:59.000Z

    Submillimetre (submm) observations of WISE-selected, dusty, luminous, high-redshift galaxies have revealed intriguing overdensities around them on arcmin scales. They could be the best signposts of overdense environments on the sky.

  16. A Tactile Luminous Floor Used as a Playful Space's Skin* Tobi Delbrck, Adrian M. Whatley, Rodney Douglas, Kynan Eng, Klaus Hepp and Paul F.M.J. Verschure

    E-Print Network [OSTI]

    Delbruck, Tobi

    A Tactile Luminous Floor Used as a Playful Space's Skin* Tobi Delbrück, Adrian M. Whatley, Rodney of the novel tactile luminous floor and how the floor is used as the skin of the playful interactive space Ada--interactive space, tactile surface, luminous floor, people tracking, gamse I. INTRODUCTION Many luminous floors have

  17. Optimization Online - Efficient Heuristic Algorithms for Maximum ...

    E-Print Network [OSTI]

    T. G. J. Myklebust

    2012-11-19T23:59:59.000Z

    Nov 19, 2012 ... Efficient Heuristic Algorithms for Maximum Utility Product Pricing Problems. T. G. J. Myklebust(tmyklebu ***at*** csclub.uwaterloo.ca)

  18. A search for rapid pulsations among 9 luminous Ap stars

    E-Print Network [OSTI]

    L. M. Freyhammer; D. W. Kurtz; M. S. Cunha; G. Mathys; V. G. Elkin; J. D. Riley

    2008-01-03T23:59:59.000Z

    The rapidly oscillating Ap stars are of importance for studying the atmospheric structure of stars where the process of chemical element diffusion is significant. We have performed a survey for rapid oscillations in a sample of 9 luminous Ap stars, selected from their location in the colour-magnitude diagram as more evolved main-sequence Ap stars that are inside the instability strip for rapidly oscillating Ap (roAp) stars. Until recently this region was devoid of stars with observed rapid pulsations. We used the VLT UV-Visual Echelle Spectrograph (UVES) to obtain high time resolution spectroscopy to make the first systematic spectroscopic search for rapid oscillations in this region of the roAp instability strip. We report 9 null-detections with upper limits for radial-velocity amplitudes of 20 - 65 m/s and precisions of 7 - 20 m/s for combinations of Nd and Pr lines. Cross-correlations confirm these null-results. At least six stars are magnetic and we provide magnetic field measurements for four of them, of which three are newly discovered magnetic stars. It is found that four stars have magnetic fields smaller than ~ 2 kG, which according to theoretical predictions might be insufficient for suppressing envelope convection around the magnetic poles for more evolved Ap stars. Suppression of convection is expected to be essential for the opacity mechanism acting in the hydrogen ionisation zone to drive the high-overtone roAp pulsations efficiently. Our null-results suggest that the more evolved roAp stars may require particularly strong magnetic fields to pulsate. Three of the studied stars do, however, have magnetic fields stronger than 5 kG.

  19. Development of High Efficacy, Low Cost Phosphorescent Oled Lightning Luminaire

    SciTech Connect (OSTI)

    Michael Hack

    2010-07-09T23:59:59.000Z

    In this two year program, UDC together with Armstrong World Industries, Professor Stephen Forrest (University of Michigan) and Professor Mark Thompson (University of Southern California) planned to develop and deliver high efficiency OLED lighting luminaires as part of an integrated ceiling illumination system that exceed the Department of Energy (DOE) 2010 performance projections. Specifically the UDC team in 2010 delivered two prototype OLED ceiling illumination systems, each consisting of four individual OLED lighting panels on glass integrated into Armstrong's novel TechZone open architecture ceiling systems, at an overall system efficacy of 51 lm/W, a CRI = 85 and a projected lifetime to 70% of initial luminance to exceed 10,000 hours. This accomplishment represents a 50% increase in luminaire efficacy and a factor of two in lifetime over that outlined in the solicitation. In addition, the team has also delivered one 15cm x 15cm lighting panel fabricated on a flexible metal foil substrate, demonstrating the possibility using OLEDs in a range of form factors. During this program, our Team has pursued the commercialization of these OLED based ceiling luminaires, with a goal to launch commercial products within the next three years. We have proven that our team is ideally suited to develop these highly novel and efficient solid state lighting luminaires, having both the technical experience and commercial strategy to leverage work performed under this contract. Our calculations show that the success of our program could lead to energy savings of more than 0.5 quads or 8 MMTC (million metric tons of carbon) per year by 2016.

  20. Maximum entropy segmentation of broadcast news 

    E-Print Network [OSTI]

    Christensen, Heidi; Kolluru, BalaKrishna; Gotoh, Yoshihiko; Renals, Steve

    2005-01-01T23:59:59.000Z

    speech recognizer and subsequently segmenting the text into utterances and topics. A maximum entropy approach is used to build statistical models for both utterance and topic segmentation. The experimental work addresses the effect on performance...

  1. LED Record Efficacy and Brightness

    Broader source: Energy.gov [DOE]

    Designed for general lighting applications such as street, industrial, and parking garage lighting, the Cree XLamp® power LED sets new records for LED brightness and efficacy, up to 85 lm/W at 350 mA. The XLamp utilizes Cree's performance breakthrough EZBright™ LED chip; both products include technology that was developed in part with R&D funding support from DOE.

  2. LSQ14bdq: A Type Ic super-luminous supernova with a double-peaked light curve

    E-Print Network [OSTI]

    Nicholl, M; Jerkstrand, A; Sim, S A; Inserra, C; Anderson, J P; Baltay, C; Benetti, S; Chambers, K; Chen, T -W; Elias-Rosa, N; Feindt, U; Flewelling, H A; Fraser, M; Gal-Yam, A; Galbany, L; Huber, M E; Kangas, T; Kankare, E; Kotak, R; Krühler, T; Maguire, K; McKinnon, R; Rabinowitz, D; Rostami, S; Schulze, S; Smith, K W; Sullivan, M; Tonry, J L; Valenti, S; Young, D R

    2015-01-01T23:59:59.000Z

    We present data for LSQ14bdq, a hydrogen-poor super-luminous supernova (SLSN) discovered by the La Silla QUEST survey and classified by the Public ESO Spectroscopic Survey of Transient Objects. The spectrum and light curve are very similar to slow-declining SLSNe such as PTF12dam. However, detections within $\\sim1$ day after explosion show a bright and relatively fast initial peak, lasting for $\\sim15$ days, prior to the usual slow rise to maximum light. The broader, main peak can be fit with either central engine or circumstellar interaction models. We discuss the implications of the precursor peak in the context of these models. It is too bright and narrow to be explained as a normal \\Ni-powered SN, and we suggest that interaction models may struggle to fit the precursor and main peak simultaneously. We propose that the initial peak is from the post-shock cooling of an extended stellar envelope, and reheating by a central engine drives the second peak. In this picture, we show that an explosion energy of $\\...

  3. A Three-Decade Outburst of the LMC Luminous Blue Variable R127 Draws to a Close

    E-Print Network [OSTI]

    Nolan R. Walborn; Otmar Stahl; Roberto C. Gamen; Thomas Szeifert; Nidia I. Morrell; Nathan Smith; Ian D. Howarth; Roberta M. Humphreys; Howard E. Bond; Daniel J. Lennon

    2008-07-09T23:59:59.000Z

    The paradigmatic Luminous Blue Variable R127 in the Large Magellanic Cloud has been found in the intermediate, peculiar early-B state, and substantially fainter in visual light, signaling the final decline from its major outburst that began between 1978 and 1980. This transformation was detected in 2008 January, but archival data show that it began between early 2005 and early 2007. In fact, significant changes from the maximum, peculiar A-type spectrum, which was maintained from 1986 through 1998, had already begun the following year, coinciding with a steep drop in visual light. We show detailed correspondences between the spectrum and light, in which the decline mimics the rise. Moreover, these trends are not monotonic but are characterized by multiple spikes and dips, which may provide constraints on the unknown outburst mechanism. Intensive photometric and spectroscopic monitoring of R127 should now resume, to follow the decline presumably back to the quiescent Ofpe/WN9 state, in order to fully document the remainder of this unique observational opportunity.

  4. Cell development obeys maximum Fisher information

    E-Print Network [OSTI]

    B. R. Frieden; R. A. Gatenby

    2014-04-29T23:59:59.000Z

    Eukaryotic cell development has been optimized by natural selection to obey maximal intracellular flux of messenger proteins. This, in turn, implies maximum Fisher information on angular position about a target nuclear pore complex (NPR). The cell is simply modeled as spherical, with cell membrane (CM) diameter 10 micron and concentric nuclear membrane (NM) diameter 6 micron. The NM contains about 3000 nuclear pore complexes (NPCs). Development requires messenger ligands to travel from the CM-NPC-DNA target binding sites. Ligands acquire negative charge by phosphorylation, passing through the cytoplasm over Newtonian trajectories toward positively charged NPCs (utilizing positive nuclear localization sequences). The CM-NPC channel obeys maximized mean protein flux F and Fisher information I at the NPC, with first-order delta I = 0 and approximate 2nd-order delta I = 0 stability to environmental perturbations. Many of its predictions are confirmed, including the dominance of protein pathways of from 1-4 proteins, a 4nm size for the EGFR protein and the approximate flux value F =10^16 proteins/m2-s. After entering the nucleus, each protein ultimately delivers its ligand information to a DNA target site with maximum probability, i.e. maximum Kullback-Liebler entropy HKL. In a smoothness limit HKL approaches IDNA/2, so that the total CM-NPC-DNA channel obeys maximum Fisher I. Thus maximum information approaches non-equilibrium, one condition for life.

  5. Spectroscopic Target Selection for the Sloan Digital Sky Survey: The Luminous Red Galaxy Sample

    E-Print Network [OSTI]

    D. J. Eisenstein; J. Annis; J. E. Gunn; A. S. Szalay; A. J. Connolly; R. C. Nichol; N. A. Bahcall; M. Bernardi; S. Burles; F. J. Castander; M. Fukugita; D. W. Hogg; Z. Ivezic; G. R. Knapp; R. H. Lupton; V. Narayanan; M. Postman; D. E. Riechart; M. Richmond; D. P. Schneider; D. J. Schlegel; M. A. Strauss; M. SubbaRao; D. L. Tucker; D. Vanden Berk; M. S. Vogeley; D. H. Weinberg; B. Yanny

    2001-08-09T23:59:59.000Z

    We describe the target selection and resulting properties of a spectroscopic sample of luminous, red galaxies (LRG) from the imaging data of the Sloan Digital Sky Survey (SDSS). These galaxies are selected on the basis of color and magnitude to yield a sample of luminous, intrinsically red galaxies that extends fainter and further than the main flux-limited portion of the SDSS galaxy spectroscopic sample. The sample is designed to impose a passively-evolving luminosity and rest-frame color cut to a redshift of 0.38. Additional, yet more luminous, red galaxies are included to a redshift of 0.5. Approximately 12 of these galaxies per square degree are targeted for spectroscopy, so the sample will number over 100,000 with the full survey. SDSS commissioning data indicate that the algorithm efficiently selects luminous (M_g=-21.4), red galaxies, that the spectroscopic success rate is very high, and that the resulting set of galaxies is approximately volume-limited out to z=0.38. When the SDSS is complete, the LRG spectroscopic sample will fill over 1h^-3 Gpc^3 with an approximately homogeneous population of galaxies and will therefore be well suited to studies of large-scale structure and clusters out to z=0.5.

  6. Tracing luminous and dark matter with the Sloan Digital Sky Survey

    E-Print Network [OSTI]

    Jon Loveday; for the SDSS collaboration

    2001-08-30T23:59:59.000Z

    I summarize the scientific goals and current status of the Sloan Digital Sky Survey, briefly describe the Early Data Release, and discuss some recent scientific results obtained from commissioning data which are apposite to the distribution of luminous and dark matter in the Universe.

  7. Classical disordered ground states: Super-ideal gases and stealth and equi-luminous materials

    E-Print Network [OSTI]

    Torquato, Salvatore

    Classical disordered ground states: Super-ideal gases and stealth and equi-luminous materials of Materials, Princeton University, Princeton, New Jersey 08544, USA 4 Program in Applied and Computational focus on three classes of configurations with unique radiation scattering characteristics: i "stealth

  8. Discovery of a luminous white dwarf in a young star cluster in the Large Magellanic Cloud

    E-Print Network [OSTI]

    Rebecca A. W. Elson; Steinn Sigurdsson; Jarrod Hurley; Melvyn B. Davies; Gerard F. Gilmore

    1998-03-19T23:59:59.000Z

    We have identified a candidate 1-2 x 10^5 year old luminous white dwarf in NGC 1818, a young star cluster in the Large Magellanic Cloud. This discovery strongly constrains the boundary mass M_c at which stars stop forming neutron stars and start forming white dwarfs, to M_c > 7.6 Msun.

  9. Transient luminous events above two mesoscale convective systems: Storm structure and evolution

    E-Print Network [OSTI]

    Rutledge, Steven

    structure and evolution Timothy J. Lang,1 Walter A. Lyons,2 Steven A. Rutledge,1 Jonathan D. Meyer,2. Meyer, D. R. MacGorman, and S. A. Cummer (2010), Transient luminous events above two mesoscale, are thought to result from dielectric breakdown at approximately 75 km height [Stanley et al., 1999

  10. Maximum Likelihood Haplotyping for General Pedigrees

    E-Print Network [OSTI]

    Friedman, Nir

    networks. The use of Bayesian networks enables efficient maximum likelihood haplotyping for more complex for the variables of the Bayesian network. The presented optimization algorithm also improves likelihood Analysis, Pedigree, superlink. Abstract Haplotype data is valuable in mapping disease-susceptibility genes

  11. Weak Scale From the Maximum Entropy Principle

    E-Print Network [OSTI]

    Yuta Hamada; Hikaru Kawai; Kiyoharu Kawana

    2014-09-23T23:59:59.000Z

    The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the Standard Model, we can check whether $S_{rad}$ actually becomes maximum at the observed values. In this paper, we regard $S_{rad}$ at the final stage as a function of the weak scale ( the Higgs expectation value ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\

  12. Weak Scale From the Maximum Entropy Principle

    E-Print Network [OSTI]

    Hamada, Yuta; Kawana, Kiyoharu

    2014-01-01T23:59:59.000Z

    The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the Standard Model, we can check whether $S_{rad}$ actually becomes maximum at the observed values. In this paper, we regard $S_{rad}$ at the final stage as a function of the weak scale ( the Higgs expectation value ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\

  13. Integrating Correlated Bayesian Networks Using Maximum Entropy

    SciTech Connect (OSTI)

    Jarman, Kenneth D.; Whitney, Paul D.

    2011-08-30T23:59:59.000Z

    We consider the problem of generating a joint distribution for a pair of Bayesian networks that preserves the multivariate marginal distribution of each network and satisfies prescribed correlation between pairs of nodes taken from both networks. We derive the maximum entropy distribution for any pair of multivariate random vectors and prescribed correlations and demonstrate numerical results for an example integration of Bayesian networks.

  14. Color and luminance asymmetries in the clear sky Javier Herna ndez-Andre s, Raymond L. Lee, Jr., and Javier Romero

    E-Print Network [OSTI]

    Lee Jr., Raymond L.

    Color and luminance asymmetries in the clear sky Javier Herna´ ndez-Andre´ s, Raymond L. Lee, Jr., and Javier Romero A long-standing assumption about the clear sky is that its colors and luminances-image analyses show that clear-sky color and luminance routinely depart perceptibly from exact symmetry

  15. A PERIOD-LUMINOSITY RELATION FOR THE SLOW VARIATIONS OF LUMINOUS BLUE VARIABLES RICHARD B. STOTHERS AND CHAO-WEN CHIN

    E-Print Network [OSTI]

    Fridlind, Ann

    A PERIOD-LUMINOSITY RELATION FOR THE SLOW VARIATIONS OF LUMINOUS BLUE VARIABLES RICHARD B. STOTHERS of light and color variation displayed by many luminous blue variables show mean ``periods. INTRODUCTION Luminous blue variables (LBVs) comprise a class of intrin- sically bright stars that display

  16. OUTFLOW-INDUCED DYNAMICAL AND RADIATIVE INSTABILITY IN STELLAR ENVELOPES WITH AN APPLICATION TO LUMINOUS BLUE VARIABLES AND WOLF-RAYET STARS

    E-Print Network [OSTI]

    TO LUMINOUS BLUE VARIABLES AND WOLF-RAYET STARS Richard B. Stothers Institute for Space Studies, NASA Goddard luminous blue variables (LBVs) may well belong to such a phase. A simple time-dependent theory of moving. INTRODUCTION The evolutionary status of the luminous blue variables (LBVs or S Doradus variables

  17. 250 J. Opt. Soc. Am. A/Vol. 12, No. 2/February 1995 M. A. Losada and K. T. Mullen Color and luminance spatial tuning estimated by

    E-Print Network [OSTI]

    Mullen, Kathy T.

    and luminance spatial tuning estimated by noise masking in the absence of off-frequency looking M. Angeles for pattern detection and obtained bandwidths for chro- matic and luminance mechanisms in conditions free from distributed per octave. Stimuli were modulated in the chromatic (isoluminant red­green) or the luminance

  18. QCD Level Density from Maximum Entropy Method

    E-Print Network [OSTI]

    Shinji Ejiri; Tetsuo Hatsuda

    2005-09-24T23:59:59.000Z

    We propose a method to calculate the QCD level density directly from the thermodynamic quantities obtained by lattice QCD simulations with the use of the maximum entropy method (MEM). Understanding QCD thermodynamics from QCD spectral properties has its own importance. Also it has a close connection to phenomenological analyses of the lattice data as well as experimental data on the basis of hadronic resonances. Our feasibility study shows that the MEM can provide a useful tool to study QCD level density.

  19. Tissue Radiation Response with Maximum Tsallis Entropy

    SciTech Connect (OSTI)

    Sotolongo-Grau, O.; Rodriguez-Perez, D.; Antoranz, J. C.; Sotolongo-Costa, Oscar [UNED, Departamento de Fisica Matematica y de Fluidos, 28040 Madrid (Spain); UNED, Departamento de Fisica Matematica y de Fluidos, 28040 Madrid (Spain) and University of Havana, Catedra de Sistemas Complejos Henri Poincare, Havana 10400 (Cuba); University of Havana, Catedra de Sistemas Complejos Henri Poincare, Havana 10400 (Cuba)

    2010-10-08T23:59:59.000Z

    The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.

  20. A global maximum power point tracking DC-DC converter

    E-Print Network [OSTI]

    Duncan, Joseph, 1981-

    2005-01-01T23:59:59.000Z

    This thesis describes the design, and validation of a maximum power point tracking DC-DC converter capable of following the true global maximum power point in the presence of other local maximum. It does this without the ...

  1. articulatorily constrained maximum: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    weight spanning forests. Amitabha Bagchi; Ankur Bhargava; Torsten Suel 2005-01-01 27 Maximum Entropy Correlated Equilibria MIT - DSpace Summary: We study maximum entropy...

  2. Dust covering factor, silicate emission and star formation in luminous QSOs

    E-Print Network [OSTI]

    R. Maiolino; O. Shemmer; M. Imanishi; H. Netzer; E. Oliva; D. Lutz; E. Sturm

    2007-04-12T23:59:59.000Z

    We present Spitzer IRS low resolution, mid-IR spectra of a sample of 25 high luminosity QSOs at 2silicate emission feature in the average spectrum, but also in four individual objects. These are the Silicate emission in the most luminous objects obtained so far. When combined with the silicate emission observed in local, low luminosity type-I AGNs, we find that the silicate emission strength is correlated with luminosity. The silicate strength of all type-I AGNs also follows a positive correlation with the black hole mass and with the accretion rate. The Polycyclic Aromatic Hydrocarbon (PAH) emission features, expected from starburst activity, are not detected in the average spectrum of luminous, high-z QSOs. The upper limit inferred from the average spectrum points to a ratio between PAH luminosity and QSO optical luminosity significantly lower than observed in lower luminosity AGNs, implying that the correlation between star formation rate and AGN power saturates at high luminosities.

  3. A Luminous Red Nova in M31 and its Progenitor System

    E-Print Network [OSTI]

    Williams, S C; Bode, M F; Steele, I A

    2015-01-01T23:59:59.000Z

    We present observations of M31LRN 2015 (MASTER OT J004207.99+405501.1), discovered in M31 in January 2015, and identified as a rare and enigmatic luminous red nova (LRN). Spectroscopic and photometric observations obtained by the Liverpool Telescope showed the LRN becoming extremely red as it faded from its M(V) = -9.4 +/- 0.2 peak. Early spectra showed strong Halpha emission that weakened over time as a number of absorption features appeared, including Na I D and Ba II. At later times strong TiO absorption bands were also seen. A search of archival Hubble Space Telescope data revealed a luminous red source to be the likely progenitor system, with pre-outburst Halpha emission also detected in ground-based data. The outburst of M31LRN 2015 shows many similarities, both spectroscopically and photometrically, with that of V838 Mon, the best studied LRN. We finally discuss the possible progenitor scenarios.

  4. The peculiar case of the "double-humped" super-luminous supernova SN2006oz

    E-Print Network [OSTI]

    Rachid Ouyed; Denis Leahy

    2012-02-11T23:59:59.000Z

    SN2006oz is a super-luminous supernova with a mysterious bright precursor that has resisted explanation in standard models. However, such a precursor has been predicted in the dual-shock quark nova (dsQN) model of super-luminous supernovae -- the precursor is the SN event while the main light curve of the SLSN is powered by the Quark-Nova (QN; explosive transition of the neutron star to a quark star). As the SN is fading, the QN re-energizes the SN ejecta, producing a "double-humped" light curve. In this paper, we show the dsQN model successfully reproduces the observed light curve of SN2006oz.

  5. 2.1E Supplement

    E-Print Network [OSTI]

    Winkelmann, F.C.

    2010-01-01T23:59:59.000Z

    from theoretical CIE sky luminance distributions LuminanceBACKG LUM FAC -SKY (background luminance factor -sky) is thefrom clear part of sky (lumens/watt) Luminance efficacy of

  6. The winds of Luminous Blue Variables and the Mass of AG Car

    E-Print Network [OSTI]

    Jorick S. Vink; Alex de Koter

    2002-07-15T23:59:59.000Z

    We present radiation-driven wind models for Luminous Blue Variables (LBVs) and predict their mass-loss rates. A comparison between our predictions and the observations of AG Car shows that the variable mass loss behaviour of LBVs is due the recombination/ionisation of Fe IV/III and Fe III/II. We also derive a present-day mass of 35 Msun for AG Car.

  7. Luminant's Big Brown Plant wins for continuous improvement and safety programs

    SciTech Connect (OSTI)

    Peltier, R.

    2008-07-15T23:59:59.000Z

    Staff from Luminant's Big Brown Plant accepted the PRB Coal Users' Group's top honour for innovative improvements to coal-handling systems and a sterling safety record. The numbers reveal their accomplishments: an average EFOR less than 4%, an availability factor averaging 90% for a plant that burns a lignite/PRB mix, and staff who worked more than 2.6 million man-hours since March 2000 without a lost-time injury. 13 photos., 1 tab.

  8. Identification of four RXTE Slew Survey sources with nearby luminous active galactic nuclei

    E-Print Network [OSTI]

    M. Revnivtsev; S. Sazonov; E. Churazov; S. Trudolyubov

    2005-11-17T23:59:59.000Z

    Based on RXTE scans and observations with the SWIFT/XRT telescope and INTEGRAL observatory, we report the identification of four X-ray sources discovered during the RXTE Slew Survey of the |b|>10deg sky with nearby (z ~ 0.017-0.098) luminous (log L_2-10keV ~ 42.7-44 erg/s) active galactic nuclei. Two of the objects exhibit heavily intrinsically absorbed X-ray spectra (NHL~10^23 cm^-2).

  9. Luminous HC3N line emission in NGC4418 - buried AGN or nascent starburst?

    E-Print Network [OSTI]

    S. Aalto; R. Monje; S. Martin

    2007-05-21T23:59:59.000Z

    IRAM 30m observations reveal that the deeply obscured IR-luminous galaxy NGC4418 has a rich molecular chemistry - including unusually luminous HC3N line emission. We furthermore detect: ortho-H2CO 2-1, 3-2; CN 1-0, 2-1; HCO+, 1-0. 3-2, HCN 3-2, HNC 1-0, 3-2 (and tentatively OCS 12-11). The HCN, HCO+, H2CO and CN line emission can be fitted to densities of n=5 x 10E4 - 10E5 cm-3 and gas temperatures Tk=80-150 K. Both HNC and HC3N are, however, significantly more excited than the other species which requires higher gas densities - or radiative excitation through e.g. mid-IR pumping. The HCN line intensity is fainter than that of HCO+ and HNC for the 3-2 transition, in contrast to previous findings for the 1-0 lines where the HCN emission is the most luminous. We tentatively suggest that the observed molecular line emission is consistent with a young starburst, where the emission can be understood as emerging from dense, warm gas with an additional PDR component. We find that X-ray chemistry is not required to explain the observed mm line emission, including the HCN/HCO+ 1-0 and 3-2 line ratios. The luminous HC3N line emission is an expected signature of dense, starforming gas. A deeply buried AGN can not be excluded, but its impact on the surrounding molecular medium is then suggested to be limited. However, detailed modelling of HC3N abundances in X-ray dominated regions (XDRs) should be carried out. The possibility of radiative excitation should also be further investigated

  10. The X-ray emission of the most luminous 3CR radio sources

    E-Print Network [OSTI]

    M. Salvati; G. Risaliti; P. Veron; L. Woltjer

    2007-10-29T23:59:59.000Z

    We investigate the X-ray properties of the most luminous radio sources in the 3CR catalogue, in order to assess if they are similar to the most luminous radio quiet quasars, for instance in the X-ray normalization with respect to the optical luminosity, or in the distribution of the absorption column density. We have selected the (optically identified) 3CR radio sources whose 178-MHz monochromatic luminosity lies in the highest factor-of-three bin. The 4 most luminous objects had already been observed in X rays. Of the remaining 16, we observed with XMM-Newton 4 randomly chosen, optical type 1s, and 4 type 2s. All targets have been detected. The optical-to-Xray spectral index, alphaox, can be computed only for the type 1s and, in agreement with previous studies, is found to be flatter than in radio quiet quasars of similar luminosity. However, the Compton thin type 2s have an absorption corrected X-ray luminosity systematically lower than the type 1s, by a factor which makes them consistent with the radio quiet alphaox. Within the limited statistics, the Compton thick objects seem to have a reflected component more luminous than the Compton thin ones. The extra X-ray component observed in type 1 radio loud quasars is beamed for intrinsic causes, and is not collimated by the absorbing torus as is the case for the (intrinsically isotropic) disk emission. The extra component can be associated with a relativistic outflow, provided that the flow opening angle and the Doppler beaming factor are 1/5 - 1/7 radians.

  11. Spitzer Mid-Infrared Spectroscopy of Infrared Luminous Galaxies at z~2 I: the Spectra

    E-Print Network [OSTI]

    Lin Yan; Anna Sajina; Dario Fadda; Phil Choi; Lee Armus; George Helou; Harry Teplitz; David Frayer; Jason Surace

    2006-12-12T23:59:59.000Z

    We present the mid-infrared (MIR) spectra obtained with the Spitzer InfraRed Spectrograph (IRS) for a sample of 52 sources, selected as infrared luminous, z>1 candidates in the Extragalactic First Look Survey (XFLS). The sample selection criteria are f(24um) > 0.9mJy, nu fnu(24um)/nu fnu(8um) > 3.16 and nu fnu(24um)/nu fnu(0.7um) > 10. Of the 52 spectra, 47 (90%) produced measurable redshifts based solely on the mid-IR spectral features, with the majority (35/47=74%) at 1.5 1. Their $L_{1600\\AA}$ and $L_{\\rm IR}$ suggest that our sample is among the most luminous and most dust enshrouded systems of its epoch . Our study has revealed a significant population of dust enshrouded galaxies at z~2, whose enormous energy output, comparable to that of quasars, is generated by AGN as well as starburst. This IR luminous population has very little overlap with sub-mm and UV-selected populations (Abridged).

  12. Comparison of dust-to-gas ratios in luminous, ultraluminous, and hyperluminous infrared galaxies

    E-Print Network [OSTI]

    M. Contini; T. Contini

    2007-05-24T23:59:59.000Z

    The dust-to-gas ratios in three different samples of luminous, ultraluminous, and hyperluminous infrared galaxies are calculated by modelling their radio to soft X-ray spectral energy distributions using composite models which account for the photoionizing radiation from HII regions, starbursts, or AGNs, and for shocks. The models are limited to a set which broadly reproduces the mid-IR fine structure line ratios of local, IR bright, starburst galaxies. The results show that two types of clouds contribute to the IR emission. Those characterized by low shock velocities and low preshock densities explain the far-IR dust emission, while those with higher velocities and densities contribute to mid-IR dust emission. An AGN is found in nearly all of the ultraluminous IR galaxies and in half of the luminous IR galaxies of the sample. High IR luminosities depend on dust-to-gas ratios of about 0.1 by mass, however, most hyperluminous IR galaxies show dust-to-gas ratios much lower than those calculated for the luminous and ultraluminous IR galaxies.

  13. 3D spectroscopy with VLT/GIRAFFE - II: Are Luminous Compact Galaxies merger remnants ?

    E-Print Network [OSTI]

    M. Puech; F. Hammer; H. Flores; G. Ostlin; T. Marquart

    2006-03-21T23:59:59.000Z

    Luminous Compact Galaxies are enigmatic sources by many aspects. They can reach the luminosity of the Milky Way within a radius of only a few kpc. They also represent one of the most rapidly evolving populations of galaxies since they represent up to 1/5 of the luminous galaxies at redshift z= 0.7 while being almost absent in the local Universe. The measurement of their dynamics is crucial to our understanding of LCGs since this has the potential of telling us which physical process(es) that drives them, and ultimately to link them to the existing present-day galaxies. Here we derive the 3 dimensional velocity fields and velocity dispersion (sigma) maps of 17 Luminous Compact Galaxies selected from the Canada France Redshift Survey and the Hubble Deep Field South with redshifts ranging from z=0.4 to z=0.75. We find that only 18% of them show rotational velocity fields typical of rotating disks, the others showing more complex kinematics. Assuming that LCGs are not too far from equilibrium, about half of LCGs then appear to be either non-relaxed objects, or objects that are not supported by velocity dispersion alone. This supports the view that an important fraction of LCGs are probably mergers. It brings additional support to the ``spiral rebuilding scenario'' in which LCGs correspond to a previous or post-merger phase before the disk re-building.

  14. The Artificial Sky Luminance And The Emission Angles Of The Upward Light Flux

    E-Print Network [OSTI]

    P. Cinzano; F. J. Diaz Castro

    1998-11-19T23:59:59.000Z

    The direction of the upward light emission has different polluting effects on the sky depending on the distance of the observation site. We studied with detailed models for light pollution propagation the ratio $(b_{H})/(b_{L})$, at given distances from a city, between the artificial sky luminance $b_{H}$ produced by its upward light emission between a given threshold angle $\\theta_{0}$ and the vertical and the artificial sky luminance $b_{L}$ produced by its upward light emission between the horizontal and the threshold angle $\\theta_{0}$. Our results show that as the distance from the city increases the effects of the emission at high angles above the horizontal decrease relative to the effects of emission at lower angles above the horizontal. Outside some kilometers from cities or towns the light emitted between the horizontal and 10\\deg ~is as important as the light emitted at all the other angles in producing the artificial sky luminance. Therefore the protection of a site requires also a careful control of this emission which needs to be reduced to at most 1/10 of the remaining emission. The emission between the horizontal and 10\\deg ~is mostly produced by spill light from luminaires, so fully shielded fixtures (e.g. flat glass luminaires or asymmetric spot-lights installed without any tilt) are needed for this purpose.

  15. Epimorphin mediates mammary luminal morphogenesis through control of C/EBPbeta

    SciTech Connect (OSTI)

    Hirai, Yohei; Radisky, Derek; Boudreau, Rosanne; Simian, Marina; Stevens, Mary E.; Oka, Yumiko; Takebe, Kyoko; Niwa, Shinichiro; Bissell, Mina J.

    2002-03-22T23:59:59.000Z

    We have previously shown that epimorphin, a protein expressed on the surface of myoepithelial and fibroblast cells of the mammary gland, acts as a multifunctional morphogen of mammary epithelial cells. Here, we present the molecular mechanism by which epimorphin mediates luminal morphogenesis. Treatment of cells with epimorphin to induce lumen formation greatly increases the overall expression of transcription factor CCAAT/enhancer binding protein beta (C/EBPbeta) and alters the relative expression of its two principal isoforms, LIP and LAP. These alterations were shown to be essential for the morphogenetic activities, as constitutive expression of LIP was sufficient to produce lumen formation, while constitutive expression of LAP blocked epimorphin-mediated luminal morphogenesis. Furthermore, in a transgenic mouse model in which epimorphin expression was expressed in an apolar fashion on the surface of mammary epithelial cells, we found increased expression of C/EBPbeta, increased relative expression of LIP to LAP, and enlarged ductal lumina. Together, our studies demonstrate a role for epimorphin in luminal morphogenesis through control of C/EBPbeta expression.

  16. Conductivity maximum in a charged colloidal suspension

    SciTech Connect (OSTI)

    Bastea, S

    2009-01-27T23:59:59.000Z

    Molecular dynamics simulations of a charged colloidal suspension in the salt-free regime show that the system exhibits an electrical conductivity maximum as a function of colloid charge. We attribute this behavior to two main competing effects: colloid effective charge saturation due to counterion 'condensation' and diffusion slowdown due to the relaxation effect. In agreement with previous observations, we also find that the effective transported charge is larger than the one determined by the Stern layer and suggest that it corresponds to the boundary fluid layer at the surface of the colloidal particles.

  17. SPECTROSCOPIC OBSERVATIONS OF SN 2012fr: A LUMINOUS, NORMAL TYPE Ia SUPERNOVA WITH EARLY HIGH-VELOCITY FEATURES AND A LATE VELOCITY PLATEAU

    SciTech Connect (OSTI)

    Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Cenko, S. B.; Filippenko, A. V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Silverman, J. M. [Department of Astronomy, University of Texas, Austin, TX 78712-0259 (United States); Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Jha, S. W.; McCully, C. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Anderson, J. P.; De Jaeger, T.; Forster, F. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Benetti, S. [INAF Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Bufano, F., E-mail: mjc@mso.anu.edu.au [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago (Chile); and others

    2013-06-10T23:59:59.000Z

    We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II {lambda}6355 line that can be cleanly decoupled from the lower velocity ''photospheric'' component. This Si II {lambda}6355 HVF fades by phase -5; subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of {approx}12,000 km s{sup -1} until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v Almost-Equal-To 12,000 km s{sup -1} with narrow line width and long velocity plateau, as well as an HVF beginning at v Almost-Equal-To 31,000 km s{sup -1} two weeks before maximum. SN 2012fr resides on the border between the ''shallow silicon'' and ''core-normal'' subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the ''low velocity gradient'' group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

  18. Maximum screening fields of superconducting multilayer structures

    E-Print Network [OSTI]

    Gurevich, Alex

    2015-01-01T23:59:59.000Z

    It is shown that a multilayer comprised of alternating thin superconducting and insulating layers on a thick substrate can fully screen the applied magnetic field exceeding the superheating fields $H_s$ of both the superconducting layers and the substrate, the maximum Meissner field is achieved at an optimum multilayer thickness. For instance, a dirty layer of thickness $\\sim 0.1\\; \\mu$m at the Nb surface could increase $H_s\\simeq 240$ mT of a clean Nb up to $H_s\\simeq 290$ mT. Optimized multilayers of Nb$_3$Sn, NbN, some of the iron pnictides, or alloyed Nb deposited onto the surface of the Nb resonator cavities could potentially double the rf breakdown field, pushing the peak accelerating electric fields above 100 MV/m while protecting the cavity from dendritic thermomagnetic avalanches caused by local penetration of vortices.

  19. SSL Pricing and Efficacy Trend Analysis for Utility Program Planning...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Market-Based Programs Technical Information Network SSL Pricing and Efficacy Trend Analysis for Utility Program Planning SSL Pricing and Efficacy Trend Analysis for Utility...

  20. STUDYING LARGE- AND SMALL-SCALE ENVIRONMENTS OF ULTRAVIOLET LUMINOUS GALAXIES

    SciTech Connect (OSTI)

    Basu-Zych, Antara R.; Schiminovich, David [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Heinis, Sebastien; Heckman, Tim; Bianchi, Luciana [Center for Astrophysical Sciences, The Johns Hopkins' University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Overzier, Roderik [Max-Planck-Institut fuer Astrophysik, D-85748 Garching (Germany); Zamojski, Michel; Barlow, Tom A.; Conrow, Tim; Forster, Karl G.; Friedman, Peter G.; Martin, D. Christopher; Morrissey, Patrick [California Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ilbert, Olivier [Institute for Astronomy, 2680 Woodlawn Dr., University of Hawaii, Honolulu, HI 96822 (United States); Koekemoer, Anton M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Donas, Jose; Milliard, Bruno [Laboratoire d'Astrophysique de Marseille, BP8, Traverse du Siphon, F-13376 Marseille (France); Lee, Young-Wook [Center for Space Astrophysics, Yonsei University, Seoul 120-749 (Korea, Republic of); Madore, Barry F. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Neff, Susan G. [Laboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)], E-mail: antara@astro.columbia.edu (and others)

    2009-07-10T23:59:59.000Z

    Studying the environments of 0.4 < z < 1.2 ultraviolet (UV)-selected galaxies, as examples of extreme star-forming galaxies (with star formation rates (SFRs) in the range of 3-30 M{sub sun} yr{sup -1}), we explore the relationship between high rates of star formation, host halo mass, and pair fractions. We study the large- and small-scale environments of local ultraviolet luminous galaxies (UVLGs) by measuring angular correlation functions. We cross-correlate these systems with other galaxy samples: a volume-limited sample (ALL), a blue luminous galaxy sample, and a luminous red galaxy (LRG) sample. We determine the UVLG comoving correlation length to be r{sub 0} = 4.8{sup +11.6}{sub -2.4} h {sup -1} Mpc at (z) = 1.0, which is unable to constrain the halo mass for this sample. However, we find that UVLGs form close (separation <30 kpc) pairs with the ALL sample, but do not frequently form pairs with LRGs. A rare subset of UVLGs, those with the highest FUV surface brightnesses, are believed to be local analogs of high-redshift Lyman break galaxies (LBGs) and are called Lyman break analogs (LBAs). LBGs and LBAs share similar characteristics (i.e., color, size, surface brightness, specific SFRs, metallicities, and dust content). Recent Hubble Space Telescope images of z {approx} 0.2 LBAs show disturbed morphologies, signs of mergers and interactions. UVLGs may be influenced by interactions with other galaxies and we discuss this result in terms of other high star-forming, merging systems.

  1. Luminous AGB stars in nearby galaxies. A study using Virtual Observatory tools

    E-Print Network [OSTI]

    P. Tsalmantza; E. Kontizas; L. Cambresy; F. Genova; A. Dapergolas; M. Kontizas

    2005-10-13T23:59:59.000Z

    Aims. This study focuses on very luminous Mbol1.5 mag and H-Ks>0.4 mag in the LMC, SMC, M31, and M33 from 2MASS data. Methods.The data were taken from the 2MASS All-Sky Point Source catalogue archive. We used Virtual Observatory tools and took advantage of its capabilities at various stages in the analysis. Results. It is well known that stars with the colors we selected correspond mainly to carbon stars. Although the most luminous AGBs detected here contain a large number of carbon stars,they are not included in existing catalogues produced from data in the optical domain, where they are not visible since they are dust-enshrouded. A comparison of the AGB stars detected with combined near and mid-infrared data from MSX and 2MASS in the LMC shows that 10% of the bright AGB stars are bright carbon stars never detected before and that the other 50% are OH/IR oxygen rich stars, whereas the 40% that remain were not cross-matched. Conclusions. The catalogues of the most luminous AGB stars compiled here are an important complement to existing data. In the LMC, these bright AGB stars are centrally located, whereas they are concentrated in an active star-formation ring in M31. In the SMC and M33, there are not enough of them to draw definite conclusions, although they tend to be centrally located. Their luminosity functions are similar for the four galaxies we studied.

  2. PROPERTIES OF NEWLY FORMED DUST GRAINS IN THE LUMINOUS TYPE IIn SUPERNOVA 2010jl

    SciTech Connect (OSTI)

    Maeda, K.; Nozawa, T.; Folatelli, G.; Moriya, T. J.; Nomoto, K.; Bersten, M.; Quimby, R. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Sahu, D. K.; Anupama, G. C. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Minowa, Y.; Pyo, T.-S. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Motohara, K.; Kitagawa, Y. [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ueno, I.; Kawabata, K. S.; Yamanaka, M. [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kozasa, T. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Iye, M., E-mail: keiichi.maeda@ipmu.jp [National Astronomical Observatory, Mitaka, Tokyo (Japan)

    2013-10-10T23:59:59.000Z

    Supernovae (SNe) have been proposed to be the main production sites of dust grains in the universe. However, our knowledge of their importance to dust production is limited by observationally poor constraints on the nature and amount of dust particles produced by individual SNe. In this paper, we present a spectrum covering optical through near-Infrared (NIR) light of the luminous Type IIn supernova 2010jl around one and a half years after the explosion. This unique data set reveals multiple signatures of newly formed dust particles. The NIR portion of the spectrum provides a rare example where thermal emission from newly formed hot dust grains is clearly detected. We determine the main population of the dust species to be carbon grains at a temperature of ?1350-1450 K at this epoch. The mass of the dust grains is derived to be ?(7.5-8.5) × 10{sup –4} M{sub ?}. Hydrogen emission lines show wavelength-dependent absorption, which provides a good estimate of the typical size of the newly formed dust grains (?< 0.1 ?m, and most likely ?< 0.01 ?m). We believe the dust grains were formed in a dense cooling shell as a result of a strong SN-circumstellar media (CSM) interaction. The dust grains occupy ?10% of the emitting volume, suggesting an inhomogeneous, clumpy structure. The average CSM density must be ?> 3 × 10{sup 7} cm{sup –3}, corresponding to a mass loss rate of ?> 0.02 M{sub ?} yr{sup –1} (for a mass loss wind velocity of ?100 km s{sup –1}). This strongly supports a scenario in which SN 2010jl and probably other luminous SNe IIn are powered by strong interactions within very dense CSM, perhaps created by Luminous-Blue-Variable-like eruptions within the last century before the explosion.

  3. Spatial distribution of luminous X-ray binaries in spiral galaxies

    E-Print Network [OSTI]

    Zhao-yu Zuo; Xiang-dong Li; Xi-wei Liu

    2008-06-02T23:59:59.000Z

    We have modelled the spatial distribution of luminous X-ray binaries (XRBs) in spiral galaxies that are like the Milky Way using an evolutionary population synthesis code. In agreement with previous theoretical expectations and observations, we find that both high- and low-mass XRBs show clear concentrations towards the galactic plane and bulge.We also compare XRB distributions under the galactic potential with a dark matter halo and the modified Newtonian dynamics potential, and we suggest that the difference may serve as potential evidence to discriminate between these two types of model.

  4. Tunable sub-luminal propagation of narrowband x-ray pulses

    E-Print Network [OSTI]

    K. P. Heeg; J. Haber; D. Schumacher; L. Bocklage; H. -C. Wille; K. S. Schulze; R. Loetzsch; I. Uschmann; G. G. Paulus; R. Rüffer; R. Röhlsberger; J. Evers

    2014-09-01T23:59:59.000Z

    Group velocity control is demonstrated for x-ray photons of 14.4 keV energy via a direct measurement of the temporal delay imposed on spectrally narrow x-ray pulses. Sub-luminal light propagation is achieved by inducing a steep positive linear dispersion in the optical response of ${}^{57}$Fe M\\"ossbauer nuclei embedded in a thin film planar x-ray cavity. The direct detection of the temporal pulse delay is enabled by generating frequency-tunable spectrally narrow x-ray pulses from broadband pulsed synchrotron radiation. Our theoretical model is in good agreement with the experimental data.

  5. Maximum Entropy Method Approach to $?$ Term

    E-Print Network [OSTI]

    Masahiro Imachi; Yasuhiko Shinno; Hiroshi Yoneyama

    2004-06-09T23:59:59.000Z

    In Monte Carlo simulations of lattice field theory with a $\\theta$ term, one confronts the complex weight problem, or the sign problem. This is circumvented by performing the Fourier transform of the topological charge distribution $P(Q)$. This procedure, however, causes flattening phenomenon of the free energy $f(\\theta)$, which makes study of the phase structure unfeasible. In order to treat this problem, we apply the maximum entropy method (MEM) to a Gaussian form of $P(Q)$, which serves as a good example to test whether the MEM can be applied effectively to the $\\theta$ term. We study the case with flattening as well as that without flattening. In the latter case, the results of the MEM agree with those obtained from the direct application of the Fourier transform. For the former, the MEM gives a smoother $f(\\theta)$ than that of the Fourier transform. Among various default models investigated, the images which yield the least error do not show flattening, although some others cannot be excluded given the uncertainty related to statistical error.

  6. A Maximum Likelihood Investigation Into Color Indexing Nicu Sebe Michael S. Lew

    E-Print Network [OSTI]

    Sebe, Nicu

    the color components from the luminance compo- nent. The hue and saturation of a color are represented by H and S, and the luminance is represented by V. When we create a color histogram, we must quantize each is based on the observation that often color is used to encode functionality: grass is green, sky is blue

  7. Maximum Throughput Power Control in CDMA Wireless Networks

    E-Print Network [OSTI]

    Mellor-Crummey, John

    Maximum Throughput Power Control in CDMA Wireless Networks Anastasios Giannoulis Department introduce cross­layer, distributed power control algorithms that guarantee maximum possible data throughput performing dynamic routing and scheduling together with power control. The cross­layer interaction consists

  8. GMM Estimation of a Maximum Entropy Distribution with Interval Data

    E-Print Network [OSTI]

    Perloff, Jeffrey M.

    GMM Estimation of a Maximum Entropy Distribution with Interval Data Ximing Wu* and Jeffrey M estimate it using a simple yet flexible maximum entropy density. Our Monte Carlo simulations show that the proposed maximum entropy density is able to approximate various distributions extremely well. The two

  9. Spitzer Mid-Infrared Spectroscopy of 70um-Selected Distant Luminous Infrared Galaxies

    E-Print Network [OSTI]

    Kate Brand; Dan W. Weedman; Vandana Desai; Emeric Le Floc'h; Lee Armus; Arjun Dey; Jim R. Houck; Buell T. Jannuzi; Howard A. Smith; B. T. Soifer

    2007-09-20T23:59:59.000Z

    We present mid-infrared spectroscopy obtained with the Spitzer Space Telescope of a sample of 11 optically faint, infrared luminous galaxies selected from a Spitzer MIPS 70um imaging survey of the NDWFS Bootes field. These are the first Spitzer IRS spectra presented of distant 70um-selected sources. All the galaxies lie at redshifts 0.3infrared luminosities of L_IR~ 0.1-17 x 10^12 solar luminosities. Seven of the galaxies exhibit strong emission features attributed to polycyclic aromatic hydrocarbons (PAHs). The average IRS spectrum of these sources is characteristic of classical starburst galaxies, but with much larger infrared luminosities. The PAH luminosities of L(7.7) ~ 0.4 - 7 x 10^11 solar luminosities imply star formation rates of ~ 40 - 720 solar masses per year. Four of the galaxies show deep 9.7um silicate absorption features and no significant PAH emission features (6.2um equivalent widths infrared luminosities and low f70/f24 flux density ratios suggests that these sources have AGN as the dominant origin of their large mid-infrared luminosities, although deeply embedded but luminous starbursts cannot be ruled out. If the absorbed sources are AGN-dominated, a significant fraction of all far-infrared bright, optically faint sources may be dominated by AGN.

  10. Table lamp with dynamically controlled lighting distribution and uniformly illuminated luminous shade

    DOE Patents [OSTI]

    Siminovitch, Michael J. (Pinole, CA); Page, Erik R. (Berkeley, CA)

    2002-01-01T23:59:59.000Z

    A double lamp table or floor lamp lighting system has a pair of compact fluorescent lamps (CFLs) or other lamps arranged vertically, i.e. one lamp above the other, with a reflective septum in between. By selectively turning on one or both of the CFLs, down lighting, up lighting, or both up and down lighting is produced. The control system can also vary the light intensity from each CFL. The reflective septum ensures that almost all the light produced by each lamp will be directed into the desired light distribution pattern which is selected and easily changed by the user. In a particular configuration, the reflective septum is bowl shaped, with the upper CFL sitting in the bowl, and a luminous shade hanging down from the bowl. The lower CFL provides both task lighting and uniform shade luminance. Planar compact fluorescent lamps, e.g. circular CFLs, particularly oriented horizontally, are preferable. CFLs provide energy efficiency. However, other types of lamps, including incandescent, halogen, and LEDs can also be used in the fixture. The lighting system may be designed for the home, hospitality, office or other environments.

  11. A Catalog of Luminous Infrared Galaxies in the IRAS Survey and the Second Data Release of the SDSS

    E-Print Network [OSTI]

    Chen Cao; Hong Wu; Jian-Ling Wang; Cai-Na Hao; Zu-Gan Deng; Xiao-Yang Xia; Zhen-Long Zou

    2005-11-04T23:59:59.000Z

    We select the Luminous Infrared Galaxies by cross-correlating the Faint Source Catalogue (FSC) and Point Source Catalogue (PSC) of the IRAS Survey with the Second Data Release of the SDSS for studying their infrared and optical properties. The total number of our sample is 1267 for FSC and 427 for PSC by using 2$\\sigma$ significance level cross-section. The "likelihood ratio" method is used to estimate the sample's reliability and for a more reliable subsample (908 for FSC and 356 for PSC) selection. Then a Catalog with both the infrared, optical and radio informations is presented and will be used in further works. Some statistical results show that the Luminous Infrared Galaxies are quite different from the Ultra-Luminous Infrared Galaxies. The AGN fractions of galaxies with different infrared luminosities and the radio to infrared correlations are consist with previous studies.

  12. Fine structure of the Poynting-Robertson effect for a luminous spinning relativistic star

    E-Print Network [OSTI]

    Jae Sok Oh; Hongsu Kim; Hyung Mok Lee

    2010-11-13T23:59:59.000Z

    As a sequel to our recent works challenging toward the systematic inclusion of the effect of radiation on the trajectory of a test particle orbiting around a luminous spinning relativistic star eventually aiming at its application to the accretion flow. We explore in the present work the fine structure of the trajectory of test particle just entering the ``suspension orbit" under the purpose of a detailed investigation of test particle's trajectory in the vicinity of the ``suspension orbit". We end up with a rather puzzling behavior that, contrary to our expectation, the specific angular momentum of the test particle instantly rises instead of decreasing monotonically just before the test particle enters the ``suspension orbit".

  13. A MAP OF THE INTEGRATED SACHS-WOLFE SIGNAL FROM LUMINOUS RED GALAXIES

    SciTech Connect (OSTI)

    Granett, Benjamin R.; Neyrinck, Mark C.; Szapudi, Istvan [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2009-08-10T23:59:59.000Z

    We construct a map of the time derivative of the gravitational potential traced by Sloan Digital Sky Survey luminous red galaxies (LRGs). The potential decays on large scales due to cosmic acceleration, leaving an imprint on cosmic microwave background (CMB) radiation through the integrated Sachs-Wolfe (ISW) effect. With a template fit, we directly measure this signature on the CMB at a 2{sigma} confidence level. The measurement is consistent with the cross-correlation statistic, strengthening the claim that dark energy is indeed the cause of the correlation. This new approach potentially simplifies the cosmological interpretation. Our constructed linear ISW map shows no evidence for degree-scale cold and hot spots associated with supervoid and supercluster structures. This suggests that the linear ISW effect in a concordance {lambda}CDM cosmology is insufficient to explain the strong CMB imprints from these structures that we previously reported.

  14. Properties of Luminous Red Galaxies in the Sloan Digital Sky Survey

    E-Print Network [OSTI]

    T. Barber; A. Meiksin; T. Murphy

    2006-11-02T23:59:59.000Z

    We perform population synthesis modelling of a magnitude-limited sample of 4391 Luminous Red Galaxies selected from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4). We fit measured spectral indices using a large library of high resolution spectra, covering a wide range of metallicities and assuming an exponentially decaying star-formation rate punctuated by bursts, to obtain median-likelihood estimates for the light-weighted age, metallicity, stellar mass and extinction for the galaxies. The ages lie in the range 4-10 Gyr, peaking near 6 Gyr, with metallicities in the range -0.4<[Z/H]<0.4, peaking at [Z/H] ~ 0.2. Only a few per cent of the spectra are better fit allowing for a burst in addition to continuous star-formation. The total stellar masses of all the galaxies are confined to a very narrow range. Our results broadly agree with those of previous groups using an independent population synthesis code. We find, however, that our choice in priors results in ages 1-2 Gyr smaller, decreasing the peak star formation epoch from z=2.3 to z=1.3. We develop a metal evolution model incorporating stochastic star-formation quenching motivated by recent attempts to solve the `anti-hierarchical' formation problem of ellipticals. Two scenarios emerge, a closed box with an effective stellar yield of 0.26, and an accreting box with an effective stellar yield of 0.10. Both scenarios require an IMF weighted towards massive stars and characteristic star-formation quenching times of about 100 Myr, the expected lifetime of luminous QSOs. The models predict an anti-correlation between the age and mean metallicity similar to that observed.

  15. Dynamical modelling of luminous and dark matter in 17 Coma early-type galaxies

    E-Print Network [OSTI]

    J. Thomas; R. P. Saglia; R. Bender; D. Thomas; K. Gebhardt; J. Magorrian; E. M. Corsini; G. Wegner

    2007-09-05T23:59:59.000Z

    Dynamical models for 17 Coma early-type galaxies are presented. The galaxy sample consists of flattened, rotating as well as non-rotating early-types including cD and S0 galaxies with luminosities between M=-18.79 and M=-22.56. Kinematical long-slit observations cover at least the major and minor axis and extend to 1-4 effective radii. Axisymmetric Schwarzschild models are used to derive stellar mass-to-light ratios and dark halo parameters. In every galaxy models with a dark matter halo match the data better than models without. The statistical significance is over 95 percent for 8 galaxies, around 90 percent for 5 galaxies and for four galaxies it is not significant. For the highly significant cases systematic deviations between observed and modelled kinematics are clearly seen; for the remaining galaxies differences are more statistical in nature. Best-fit models contain 10-50 percent dark matter inside the half-light radius. The central dark matter density is at least one order of magnitude lower than the luminous mass density. The central phase-space density of dark matter is often orders of magnitude lower than in the luminous component, especially when the halo core radius is large. The orbital system of the stars along the major-axis is slightly dominated by radial motions. Some galaxies show tangential anisotropy along the minor-axis, which is correlated with the minor-axis Gauss-Hermite coefficient H4. Changing the balance between data-fit and regularisation constraints does not change the reconstructed mass structure significantly. Model anisotropies tend to strengthen if the weight on regularisation is reduced, but the general property of a galaxy to be radially or tangentially anisotropic, respectively, does not change. (abridged)

  16. SUPER-LUMINOUS TYPE Ic SUPERNOVAE: CATCHING A MAGNETAR BY THE TAIL

    SciTech Connect (OSTI)

    Inserra, C.; Smartt, S. J.; Jerkstrand, A.; Fraser, M.; Wright, D.; Smith, K.; Chen, T.-W.; Kotak, R.; Nicholl, M. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Valenti, S. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102 Goleta, CA 93117 (United States); Pastorello, A.; Benetti, S. [INAF, Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Bresolin, F.; Kudritzki, R. P.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. [Institute of Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Botticella, M. T. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Ergon, M. [The Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-10691 Stockholm (Sweden); Fynbo, J. P. U., E-mail: c.inserra@qub.ac.uk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); and others

    2013-06-20T23:59:59.000Z

    We report extensive observational data for five of the lowest redshift Super-Luminous Type Ic Supernovae (SL-SNe Ic) discovered to date, namely, PTF10hgi, SN2011ke, PTF11rks, SN2011kf, and SN2012il. Photometric imaging of the transients at +50 to +230 days after peak combined with host galaxy subtraction reveals a luminous tail phase for four of these SL-SNe. A high-resolution, optical, and near-infrared spectrum from xshooter provides detection of a broad He I {lambda}10830 emission line in the spectrum (+50 days) of SN2012il, revealing that at least some SL-SNe Ic are not completely helium-free. At first sight, the tail luminosity decline rates that we measure are consistent with the radioactive decay of {sup 56}Co, and would require 1-4 M{sub Sun} of {sup 56}Ni to produce the luminosity. These {sup 56}Ni masses cannot be made consistent with the short diffusion times at peak, and indeed are insufficient to power the peak luminosity. We instead favor energy deposition by newborn magnetars as the power source for these objects. A semi-analytical diffusion model with energy input from the spin-down of a magnetar reproduces the extensive light curve data well. The model predictions of ejecta velocities and temperatures which are required are in reasonable agreement with those determined from our observations. We derive magnetar energies of 0.4 {approx}< E(10{sup 51} erg) {approx}< 6.9 and ejecta masses of 2.3 {approx}< M{sub ej}(M{sub Sun }) {approx}< 8.6. The sample of five SL-SNe Ic presented here, combined with SN 2010gx-the best sampled SL-SNe Ic so far-points toward an explosion driven by a magnetar as a viable explanation for all SL-SNe Ic.

  17. Deficiency of large equivalent width Lyman-alpha emission in luminous Lyman break galaxies at z~5-6?

    E-Print Network [OSTI]

    Masataka Ando; Kouji Ohta; Ikuru Iwata; Masayuki Akiyama; Kentaro Aoki; Naoyuki Tamura

    2006-06-28T23:59:59.000Z

    We report a deficiency of luminous Lyman break galaxies (LBGs) with a large rest-frame equivalent width (EW_rest) of Lyman-alpha emission at z~5-6. Combining our spectroscopic sample of LBGs at z~5 and those from the literature, we found that luminous LBGs at z~5-6 generally show weak Lyman-alpha emissions, while faint LBGs show a wide range of Lyman-alpha EW_rest and tend to have strong (EW_rest >20A) Lyman-alpha emissions; i.e., there is a deficiency of strong Lyman-alpha emission in luminous LBGs. There seems to be a threshold UV luminosity for the deficiency; it is M_1400 = -21.5 \\~ -21.0 mag, which is close to or somewhat brighter than the M* of the UV luminosity function at z~5 and 6. Since the large EW_rest of Lyman-alpha emission can be seen among the faint LBGs, the fraction of Lyman-alpha emitters in LBGs may change rather abruptly with the UV luminosity. If the weakness of Lyman-alpha emission is due to dust absorption, the deficiency suggests that luminous LBGs at z=5-6 tend to be in dusty and more chemically evolved environments and started star formation earlier than faint ones, though other causes cannot be ruled out.

  18. A Hubble Space Telescope Survey of X-ray Luminous Galaxy Clusters: Gravitationally Lensed Arcs and EROs

    E-Print Network [OSTI]

    Graham P. Smith

    2002-01-15T23:59:59.000Z

    We are conducting a systematic lensing survey of X-ray luminous galaxy clusters at z~0.2 using the Hubble Space Telescope and large ground-based telescopes. We summarize initial results from our survey, including a measurement of the inner slope of the mass profile of A383, and a search for gravitationally lensed Extremely Red Objects.

  19. A Near Maximum Likelihood Decoding Algorithm for MIMO Systems ...

    E-Print Network [OSTI]

    Amin Mobasher

    2005-10-03T23:59:59.000Z

    Oct 3, 2005 ... A Near Maximum Likelihood Decoding Algorithm for MIMO Systems Based ... models are also used for soft output decoding in MIMO systems.

  20. Computing the Maximum Volume Inscribed Ellipsoid of a Polytopic ...

    E-Print Network [OSTI]

    Jianzhe Zhen

    2015-01-23T23:59:59.000Z

    Jan 23, 2015 ... Abstract: This paper introduces a method for computing the maximum volume inscribed ellipsoid and k-ball of a projected polytope. It is known ...

  1. Solving Maximum-Entropy Sampling Problems Using Factored Masks

    E-Print Network [OSTI]

    Samuel Burer

    2005-03-02T23:59:59.000Z

    Mar 2, 2005 ... Abstract: We present a practical approach to Anstreicher and Lee's masked spectral bound for maximum-entropy sampling, and we describe ...

  2. A masked spectral bound for maximum-entropy sampling

    E-Print Network [OSTI]

    Kurt Anstreicher

    2003-09-16T23:59:59.000Z

    Sep 16, 2003 ... Abstract: We introduce a new masked spectral bound for the maximum-entropy sampling problem. This bound is a continuous generalization of ...

  3. Maximum entropy generation in open systems: the Fourth Law?

    E-Print Network [OSTI]

    Umberto Lucia

    2010-11-17T23:59:59.000Z

    This paper develops an analytical and rigorous formulation of the maximum entropy generation principle. The result is suggested as the Fourth Law of Thermodynamics.

  4. annual maximum extent: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the Sixteenth Annual Conference on Neural Information Processing Systems (NIPS2002) A Maximum Entropy Approach To Computer Technologies and Information Sciences Websites...

  5. analog fixed maximum: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    state for given entanglement which can be viewed as an analogue of the Jaynes maximum entropy principle. Pawel Horodecki; Ryszard Horodecki; Michal Horodecki 1998-05-22...

  6. IBM Research Report Solving Maximum-Entropy Sampling ...

    E-Print Network [OSTI]

    2005-02-28T23:59:59.000Z

    Feb 28, 2005 ... Solving Maximum-Entropy Sampling Problems Using. Factored Masks. Samuel Burer. Department of Management Sciences. University of Iowa.

  7. A Requirement for Significant Reduction in the Maximum BTU Input...

    Energy Savers [EERE]

    A Requirement for Significant Reduction in the Maximum BTU Input Rate of Decorative Vented Gas Fireplaces Would Impose Substantial Burdens on Manufacturers A Requirement for...

  8. Appendix 22 Draft Nutrient Management Plan and Total Maximum Daily

    E-Print Network [OSTI]

    Appendix 22 Draft Nutrient Management Plan and Total Maximum Daily Load for Flathead Lake, Montana. #12;11/01/01 DRAFT i October 30, 2001 Draft Nutrient Management Plan and Total Maximum Daily Load..............................................................................................................................2-11 SECTION 3.0 APPLICABLE WATER QUALITY STANDARDS

  9. FAST SPEAKER ADAPTION VIA MAXIMUM PENALIZED LIKELIHOOD KERNEL REGRESSION

    E-Print Network [OSTI]

    Tsang Wai Hung "Ivor"

    of MLLR using non- linear regression. Specifically, kernel regression is applied with appropriate of Science and Technology Clear Water Bay, Hong Kong ABSTRACT Maximum likelihood linear regression (MLLR) has], and transformation-based methods, most notably, maximum likelihood linear regression (MLLR) adap- tation [3]. However

  10. Digital tomosynthesis mammography using a parallel maximum likelihood reconstruction method

    E-Print Network [OSTI]

    Meleis, Waleed

    Digital tomosynthesis mammography using a parallel maximum likelihood reconstruction method Tao Wu , a Radiology Department, Massachusetts General Hospital, Boston, MA 02114 b Dept. of Electrical and Computer on an iterative maximum likelihood (ML) algorithm, is developed to provide fast reconstruction for digital

  11. Linearized semiclassical initial value time correlation functions with maximum entropy analytic continuation

    E-Print Network [OSTI]

    Liu, Jian

    2008-01-01T23:59:59.000Z

    1992). J. Skilling, in Maximum entropy and Bayesian methods,1989). S. F. Gull, in Maximum entropy and Bayesian methods,with the classical maximum entropy (CME) technique (MEAC-

  12. Improved constraints on transit time distributions from argon 39: A maximum entropy approach

    E-Print Network [OSTI]

    Holzer, Mark; Primeau, Francois W

    2010-01-01T23:59:59.000Z

    Gull (1991), Bayesian maximum entropy image reconstruction,Atlantic venti- lated? Maximum entropy inversions of bottlefrom argon 39: A maximum entropy approach Mark Holzer 1,2

  13. Quantum Statistics Basis, Thermodynamic Analogies and the Degree of Confidence for Maximum Entropy Restoration and Estimation

    E-Print Network [OSTI]

    Soffer, Bernard H; Kikuchi, Ryoichi

    1994-01-01T23:59:59.000Z

    of Confidence for Maximum Entropy Restoration and EstimationApril 3, 1992) The Maximum Entropy method, using physicalare discussed. Maximum Entropy (ME) estimation has been

  14. Super-Luminal Effects for Finsler Branes as a Way to Preserve the Paradigm of Relativity Theories

    E-Print Network [OSTI]

    Sergiu I. Vacaru

    2013-02-09T23:59:59.000Z

    Using Finsler brane solutions [see details and methods in: S. Vacaru, Class. Quant. Grav. 28 (2011) 215001], we show that neutrinos may surpass the speed of light in vacuum which can be explained by trapping effects from gravity theories on eight dimensional (co) tangent bundles on Lorentzian manifolds to spacetimes in general and special relativity. In nonholonomic variables, the bulk gravity is described by Finsler modifications depending on velocity/ momentum coordinates. Possible super-luminal phenomena are determined by the width of locally anisotropic brane (spacetime) and induced by generating functions and integration functions and constants in coefficients of metrics and nonlinear connections. We conclude that Finsler brane gravity trapping mechanism may explain neutrino super-luminal effects and almost preserve the paradigm of Einstein relativity as the standard one for particle physics and gravity.

  15. Optical observations of the luminous Type IIn Supernova 2010jl for over 900 days

    E-Print Network [OSTI]

    Jencson, J E; Kochanek, C S; Shappee, B J; Stanek, K Z; Pogge, R W

    2015-01-01T23:59:59.000Z

    The luminous Type IIn Supernova (SN) 2010jl shows strong evidence for the interaction of the SN ejecta with dense circumstellar material (CSM). We present observations of SN 2010jl for $t \\sim 900$ d after its earliest detection, including a sequence of optical spectra ranging from $t = 55$ to $909$ d. We also supplement our late time spectra and the photometric measurements in the literature with an additional epoch of new, late time $BVRI$ photometry. Combining available photometric and spectroscopic data, we derive a semi-bolometric optical light curve and calculate a total radiated energy in the optical for SN 2010jl of $\\sim 3.5\\times10^{50}$ erg. We also examine the evolution of the H$\\alpha$ emission line profile in detail and find evidence for asymmetry in the profile for $t \\gtrsim 775$ d that is not easily explained by any of the proposed scenarios for this fascinating event. Finally, we discuss the interpretations from the literature of the optical and near-infrared light curves, and propose that t...

  16. A Model for Most Luminous and Long Duration Cosmic Gamma Ray Bursts

    E-Print Network [OSTI]

    Abhas Mitra

    1999-03-10T23:59:59.000Z

    We exploit the fact that General Theory of Relativity (GTR) predicts the existence of compact objects having surface gravitational redshift z_s burst rises dramatically with the value of z_c and can saturate to ~40%. This may explain a gamma ray burst of energy as high as ~5. 10**53 erg. By using the already existing detailed (Newtonian) calculations, it follows that the neutrino heating driven mass loss should be negligible, and the bulk Lorentz factor of the initial fireball could be ~1000. Most of the existing supernova calculations also show that it is extremely difficult to simulate the direct neutrino driven mass loss, and, the shock is not launched if the gravitational field becomes stronger. Since the gravitation potential well of the more compact NS is indded very deep, we do not expect additional baryonic mass ejection. So, without invoking any exotic physics (like strange stars) or overstretching any theory, we may explain most of the luminous GRBs in this simple model.

  17. Luminous Red Galaxies in Clusters: Central Occupation, Spatial Distributions, and Mis-centering

    E-Print Network [OSTI]

    Hoshino, Hanako; Lackner, Claire; Hikage, Chiaki; Rozo, Eduardo; Rykoff, Eli; Mandelbaum, Rachel; More, Surhud; More, Anupreeta; Saito, Shun; Vulcani, Benedetta

    2015-01-01T23:59:59.000Z

    Luminous Red Galaxies (LRG) from the Sloan Digital Sky Survey are considered among the best understood samples of galaxies, and they are employed in a broad range of cosmological studies. Because they form a relatively homogeneous population, with high stellar masses and red colors, they are expected to occupy halos in a relatively simple way. In this paper, we study how LRGs occupy massive halos via direct counts in clusters and we reveal several unexpected trends suggesting that the connection between LRGs and dark matter halos may not be straightforward. Using the redMaPPer cluster catalog, we derive the central occupation of LRGs as a function richness, Ncen({\\lambda}). Assuming no correlation between cluster mass and central galaxy luminosity at fixed richness, we show that clusters contain a significantly lower fraction of central LRGs than predicted from the two-point correlation function. At halo masses of 10^14.5 Msun, we find Ncen=0.73, compared to Ncen of 0.89 from correlation studies. Our central ...

  18. Star formation and the interstellar medium in z>6 UV-luminous Lyman-break galaxies

    E-Print Network [OSTI]

    Willott, Chris J; Wagg, Jeff; Wang, Ran

    2015-01-01T23:59:59.000Z

    We present Atacama Large Millimeter Array (ALMA) detections of atomic carbon line and dust continuum emission in two UV-luminous galaxies at redshift 6. The far-infrared (FIR) luminosities of these galaxies are substantially lower than similar starbursts at later cosmic epochs, indicating an evolution in the dust properties with redshift, in agreement with the evolution seen in ultraviolet (UV) attenuation by dust. The [CII] to FIR ratios are found to be higher than at low redshift showing that [CII] should be readily detectable by ALMA within the reionization epoch. One of the two galaxies shows a complex merger nature with the less massive component dominating the UV emission and the more massive component dominating the FIR line and continuum. Using the interstellar atomic carbon line to derive the systemic redshifts we investigate the velocity of Lyman alpha emission emerging from high-z galaxies. In contrast to previous work, we find no evidence for decreasing Lyman alpha velocity shifts at high-redshift...

  19. Luminous Red Galaxies: Selection and classification by combining optical and infrared photometry

    E-Print Network [OSTI]

    Prakash, Abhishek; Newman, Jeffrey A; Rao, Sandhya M

    2015-01-01T23:59:59.000Z

    We describe a new method of combining optical and infrared photometry to select Luminous Red Galaxies (LRGs) at redshifts $z > 0.6$. We explore this technique using a combination of optical photometry from CFHTLS and HST, infrared photometry from the WISE satellite, and spectroscopic or photometric redshifts from the DEEP2 Galaxy Redshift Survey or COSMOS. We present a variety of methods for testing the success of our selection, and present methods for optimization given a set of rest-frame color and redshift requirements. We have tested this selection in two different regions of the sky, the COSMOS and Extended Groth Strip (EGS) fields, to reduce the effect of cosmic/sample variance. We have used these methods to assemble large samples of LRGs for two different ancillary programs as a part of the SDSS-III/ BOSS spectroscopic survey. This technique is now being used to select $\\sim$600,000 LRG targets for SDSS-IV/eBOSS, which began observations in Fall 2014, and will be adapted for the proposed DESI survey. W...

  20. Clustering of Photometric Luminous Red Galaxies II: Cosmological Implications from the Baryon Acoustic Scale

    E-Print Network [OSTI]

    A. Carnero; E. Sanchez; M. Crocce; A. Cabre; E. Gaztanaga

    2011-09-18T23:59:59.000Z

    A new determination of the sound horizon scale in angular coordinates is presented. It makes use of ~ 0.6 x 10^6 Luminous Red Galaxies, selected from the Sloan Digital Sky Survey imaging data, with photometric redshifts. The analysis covers a redshift interval that goes from z=0.5 to z=0.6. We find evidence of the Baryon Acoustic Oscillations (BAO) signal at the ~ 2.3 sigma confidence level, with a value of theta_{BAO} (z=0.55) = (3.90 \\pm 0.38) degrees, including systematic errors. To our understanding, this is the first direct measurement of the angular BAO scale in the galaxy distribution, and it is in agreement with previous BAO measurements. We also show how radial determinations of the BAO scale can break the degeneracy in the measurement of cosmological parameters when they are combined with BAO angular measurements. The result is also in good agreement with the WMAP7 best-fit cosmology. We obtain a value of w_0 = -1.03 \\pm 0.16 for the equation of state parameter of the dark energy, Omega_M = 0.26 \\pm 0.04 for the matter density, when the other parameters are fixed. We have also tested the sensitivity of current BAO measurements to a time varying dark energy equation of state, finding w_a = 0.06 \\pm 0.22 if we fix all the other parameters to the WMAP7 best-fit cosmology.

  1. On the diversity of Super-luminous Supernovae: Ejected mass as the dominant factor

    E-Print Network [OSTI]

    Nicholl, M; Jerkstrand, A; Inserra, C; Sim, S A; Chen, T -W; Benetti, S; Fraser, M; Gal-Yam, A; Kankare, E; Maguire, K; Smith, K; Sullivan, M; Valenti, S; Young, D R; Baltay, C; Bauer, F E; Baumont, S; Bersier, D; Botticella, M -T; Childress, M; Dennefeld, M; Della Valle, M; Elias-Rosa, N; Feindt, U; Galbany, L; Hadjiyska, E; Guillou, L Le; Leloudas, G; Mazzali, P; McKinnon, R; Polshaw, J; Rabinowitz, D; Rostami, S; Scalzo, R; Schmidt, B P; Schulze, S; Sollerman, J; Taddia, F; Yuan, F

    2015-01-01T23:59:59.000Z

    H-poor super-luminous supernovae (SLSNe) are a rare and poorly understood class of explosion. We assemble the largest sample (24) of such objects to date, with griz light curves and optical spectra. We parameterize the light curve through rise and decline timescales, finding that these are highly correlated. Magnetar-powered models reproduce the correlation, with the diversity in rise and decline driven by the diffusion timescale. Circumstellar interaction models can exhibit a similar rise-decline relation, but for only a narrow density range, which may be problematic for these models. We see a similar correlation in normal SNe Ibc (powered by 56Ni), though SLSNe rise and decline more slowly, and their peak luminosity requires an additional energy source. We find that SLSN light curves are approximately 3.5 mag brighter and 3 times broader than SNe Ibc, but that the intrinsic shapes are similar. Some SLSNe (2007bi-like) have very broad light curves, possibly indicating two progenitor channels, but statistical...

  2. The Herschel view of the nebula around the luminous blue variable star AG Carinae

    E-Print Network [OSTI]

    Vamvatira-Nakou, C; Royer, P; Cox, N L J; Naze, Y; Rauw, G; Waelkens, C; Groenewegen, M A T

    2015-01-01T23:59:59.000Z

    Far-infrared Herschel PACS imaging and spectroscopic observations of the nebula around the luminous blue variable (LBV) star AG Car have been obtained along with optical imaging in the Halpha+[NII] filter. In the infrared light, the nebula appears as a clumpy ring shell that extends up to 1.2 pc with an inner radius of 0.4 pc. It coincides with the Halpha nebula, but extends further out. Dust modeling of the nebula was performed and indicates the presence of large grains. The dust mass is estimated to be ~ 0.2 Msun. The infrared spectrum of the nebula consists of forbidden emission lines over a dust continuum. Apart from ionized gas, these lines also indicate the existence of neutral gas in a photodissociation region that surrounds the ionized region. The abundance ratios point towards enrichment by processed material. The total mass of the nebula ejected from the central star amounts to ~ 15 Msun, assuming a dust-to-gas ratio typical of LBVs. The abundances and the mass-loss rate were used to constrain the e...

  3. H-beta Line Width and the UV-X-ray Spectra of Luminous AGN

    E-Print Network [OSTI]

    B. J. Wills; Z. Shang; J. M. Yuan

    2000-05-08T23:59:59.000Z

    The width of the broad H-beta emission line is the primary defining characteristic of the NLS1 class. This parameter is also an important component of Boroson and Green's optical Eigenvector 1 (EV1), which links steeper soft X-ray spectra with narrower H-beta emission, stronger H-beta blue wing, stronger optical Fe II emission, and weaker [O III] lambda 5007. Potentially, EV1 represents a fundamental physical process linking the dynamics of fueling and outflow with the accretion rate. We attempted to understand these relationships by extending the optical spectra into the UV for a sample of 22 QSOs with high quality soft-X-ray spectra, and discovered a whole new set of UV relationships that suggest that high accretion rates are linked to dense gas and perhaps nuclear starbursts. While it has been argued that narrow (BLR) H-beta means low Black Hole mass in luminous NLS1s, the C IV, lambda 1549 and Ly alpha emission lines are broader, perhaps the result of outflows driven by their high Eddington accretion rates. We present some new trends of optical-UV with X-ray spectral energy distributions. Steeper X-ray spectra appear associated with stronger UV relative to optical continua, but the presence of strong UV absorption lines is associated with depressed soft X-rays and redder optical-UV continua.

  4. The Clustering of Luminous Red Galaxies in the Sloan Digital Sky Survey Imaging Data

    E-Print Network [OSTI]

    Padmanabhan, N; Seljak, U; Makarov, A; Bahcall, Neta A; Blanton, M R; Brinkmann, J; Eisenstein, D J; Finkbeiner, D P; Gunn, J E; Hogg, D W; Ivezic, Z; Knapp, G R; Loveday, J; Lupton, R H; Nichol, R C; Schneider, D P; Strauss, M A; Tegmark, M; York, D G

    2006-01-01T23:59:59.000Z

    We present the 3D real space clustering power spectrum of a sample of \\~600,000 luminous red galaxies (LRGs) measured by the Sloan Digital Sky Survey (SDSS), using photometric redshifts. This sample of galaxies ranges from redshift z=0.2 to 0.6 over 3,528 deg^2 of the sky, probing a volume of 1.5 (Gpc/h)^3, making it the largest volume ever used for galaxy clustering measurements. We measure the angular clustering power spectrum in eight redshift slices and combine these into a high precision 3D real space power spectrum from k=0.005 (h/Mpc) to k=1 (h/Mpc). We detect power on gigaparsec scales, beyond the turnover in the matter power spectrum, on scales significantly larger than those accessible to current spectroscopic redshift surveys. We also find evidence for baryonic oscillations, both in the power spectrum, as well as in fits to the baryon density, at a 2.5 sigma confidence level. The statistical power of these data to constrain cosmology is ~1.7 times better than previous clustering analyses. Varying t...

  5. Multichannel Blind Identification: From Subspace to Maximum Likelihood Methods

    E-Print Network [OSTI]

    Tong, Lang

    Multichannel Blind Identification: From Subspace to Maximum Likelihood Methods LANG TONG, MEMBER, IEEE, AND SYLVIE PERREAU Invited Paper A review of recent blind channel estimation algorithms is pre-- Blind equalization, parameter estimation, system identification. I. INTRODUCTION A. What Is Blind

  6. Maximum containment : the most controversial labs in the world

    E-Print Network [OSTI]

    Bruzek, Alison K. (Allison Kim)

    2013-01-01T23:59:59.000Z

    In 2002, following the September 11th attacks and the anthrax letters, the United States allocated money to build two maximum containment biology labs. Called Biosafety Level 4 (BSL-4) facilities, these labs were built to ...

  7. On the maximum pressure rise rate in boosted HCCI operation

    E-Print Network [OSTI]

    Wildman, Craig B.

    This paper explores the combined effects of boosting, intake air temperature, trapped residual gas fraction, and dilution on the Maximum Pressure Rise Rate (MPRR) in a boosted single cylinder gasoline HCCI engine with ...

  8. Maximum Photovoltaic Penetration Levels on Typical Distribution Feeders: Preprint

    SciTech Connect (OSTI)

    Hoke, A.; Butler, R.; Hambrick, J.; Kroposki, B.

    2012-07-01T23:59:59.000Z

    This paper presents simulation results for a taxonomy of typical distribution feeders with various levels of photovoltaic (PV) penetration. For each of the 16 feeders simulated, the maximum PV penetration that did not result in steady-state voltage or current violation is presented for several PV location scenarios: clustered near the feeder source, clustered near the midpoint of the feeder, clustered near the end of the feeder, randomly located, and evenly distributed. In addition, the maximum level of PV is presented for single, large PV systems at each location. Maximum PV penetration was determined by requiring that feeder voltages stay within ANSI Range A and that feeder currents stay within the ranges determined by overcurrent protection devices. Simulations were run in GridLAB-D using hourly time steps over a year with randomized load profiles based on utility data and typical meteorological year weather data. For 86% of the cases simulated, maximum PV penetration was at least 30% of peak load.

  9. Bacteria Total Maximum Daily Load Task Force Final Report 

    E-Print Network [OSTI]

    Jones, C. Allan; Wagner, Kevin; Di Giovanni, George; Hauck, Larry; Mott, Joanna; Rifai, Hanadi; Srinivasan, Raghavan; Ward, George; Wythe, Kathy

    2009-01-01T23:59:59.000Z

    In September 2006, the Texas Commission on Environmental Quality (TCEQ) and Texas State Soil and Water Conservation Board (TSSWCB) charged a seven-person Bacteria Total Maximum Daily Load (TMDL) Task Force with: * examining approaches...

  10. Maximum Likelihood Decoding of Reed Solomon Codes Madhu Sudan

    E-Print Network [OSTI]

    Sudan, Madhu

    Maximum Likelihood Decoding of Reed Solomon Codes Madhu Sudan Abstract We present a randomized and Welch [4] (see, for instance, Gem- mell and Sudan [9]). In this paper we present an algorithm which

  11. Multi-Class Classification with Maximum Margin Multiple Kernel

    E-Print Network [OSTI]

    Tomkins, Andrew

    (named OBSCURE and UFO-MKL, respectively) are used to optimize primal versions of equivalent problems), the OBSCURE and UFO-MKL algorithms are compared against MCMKL #12;Multi-Class Classification with Maximum

  12. Maximum entropy method and oscillations in the diffraction cone

    E-Print Network [OSTI]

    O. Dumbrajs; J. Kontros; A. Lengyel

    2000-07-15T23:59:59.000Z

    The maximum entropy method has been applied to investigate the oscillating structure in the pbarp- and pp-elastic scattering differential cross-section at high energy and small momentum transfer. Oscillations satisfying quite realistic reliability criteria have been found.

  13. Filtering Additive Measurement Noise with Maximum Entropy in the Mean

    E-Print Network [OSTI]

    Henryk Gzyl; Enrique ter Horst

    2007-09-04T23:59:59.000Z

    The purpose of this note is to show how the method of maximum entropy in the mean (MEM) may be used to improve parametric estimation when the measurements are corrupted by large level of noise. The method is developed in the context on a concrete example: that of estimation of the parameter in an exponential distribution. We compare the performance of our method with the bayesian and maximum likelihood approaches.

  14. The maximum entropy tecniques and the statistical description of systems

    E-Print Network [OSTI]

    B. Z. Belashev; M. K. Suleymanov

    2001-10-19T23:59:59.000Z

    The maximum entropy technique (MENT) is used to determine the distribution functions of physical values. MENT naturally combines required maximum entropy, the properties of a system and connection conditions in the form of restrictions imposed on the system. It can, therefore, be employed to statistically describe closed and open systems. Examples in which MENT is used to describe equilibrium and non-equilibrium states, as well as steady states that are far from being in thermodynamic equilibrium, are discussed.

  15. Adaptive Optics Discovery of Supernova 2004ip in the Nuclear Regions of the Luminous Infrared Galaxy IRAS 18293-3413

    E-Print Network [OSTI]

    S. Mattila; P. Vaisanen; D. Farrah; A. Efstathiou; W. P. S. Meikle; T. Dahlen; C. Fransson; P. Lira; P. Lundqvist; G. Ostlin; S. Ryder; J. Sollerman

    2007-02-28T23:59:59.000Z

    We report a supernova discovery in Ks-band images from the NAOS CONICA adaptive optics (AO) system on the ESO Very Large Telescope (VLT). The images were obtained as part of a near-infrared search for highly-obscured supernovae in the nuclear regions of luminous and ultraluminous infrared galaxies. SN 2004ip is located within a circumnuclear starburst at 1.4 arcsec (or 500 pc) projected distance from the K-band nucleus of the luminous infrared galaxy IRAS 18293-3413. The supernova luminosity and light curve are consistent with a core-collapse event suffering from a host galaxy extinction of up to about 40 magnitudes in V-band which is as expected for a circumnuclear starburst environment. This is the first supernova to be discovered making use of AO correction and demonstrates the potential of the current 8-meter class telescopes equipped with AO in discovering supernovae from the innermost nuclear regions of luminous and ultraluminous infrared galaxies.

  16. ON THE NATURE OF THE PROTOTYPE LUMINOUS BLUE VARIABLE AG CARINAE. II. WITNESSING A MASSIVE STAR EVOLVING CLOSE TO THE EDDINGTON AND BISTABILITY LIMITS

    SciTech Connect (OSTI)

    Groh, J. H. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Hillier, D. J. [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Damineli, A., E-mail: jgroh@mpifr.de [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, 05508-900, Sao Paulo, SP (Brazil)

    2011-07-20T23:59:59.000Z

    We show that the significantly different effective temperatures (T{sub eff}) achieved by the luminous blue variable AG Carinae during the consecutive visual minima of 1985-1990 (T{sub eff} {approx_equal} 22,800 K) and 2000-2001 (T{sub eff} {approx_equal} 17,000 K) place the star on different sides of the bistability limit, which occurs in line-driven stellar winds around T{sub eff} {approx} 21,000 K. Decisive evidence is provided by huge changes in the optical depth of the Lyman continuum in the inner wind as T{sub eff} changes during the S Dor cycle. These changes cause different Fe ionization structures in the inner wind. The bistability mechanism is also related to the different wind parameters during visual minima: the wind terminal velocity was 2-3 times higher and the mass-loss rate roughly two times smaller in 1985-1990 than in 2000-2003. We obtain a projected rotational velocity of 220 {+-} 50 km s{sup -1} during 1985-1990 which, combined with the high luminosity (L{sub *} = 1.5 x 10{sup 6} L{sub sun}), puts AG Car extremely close to the Eddington limit modified by rotation ({Omega}{Gamma} limit): for an inclination angle of 90{sup 0}, {Gamma}{sub {Omega}} {approx}> 1.0 for M{sub sun} {approx}< 60. Based on evolutionary models and mass budget, we obtain an initial mass of {approx}100 M{sub sun} and a current mass of {approx}60-70 M{sub sun} for AG Car. Therefore, AG Car is close to, if not at, the {Omega}{Gamma} limit during visual minimum. Assuming M = 70 M{sub sun}, we find that {Gamma}{sub {Omega}} decreases from 0.93 to 0.72 as AG Car expands toward visual maximum, suggesting that the star is not above the Eddington limit during maximum phases.

  17. Spitzer Mid-Infrared Spectroscopy of Infrared Luminous Galaxies at z~2 II: Diagnostics

    E-Print Network [OSTI]

    Anna Sajina; Lin Yan; Lee Armus; Phil Choi; Dario Fadda; George Helou; Henrik Spoon

    2007-04-13T23:59:59.000Z

    We present mid-IR spectral decomposition of a sample of 48 Spitzer-selected ULIRGs spanning z~1-3 and likely L_IR~10^12-10^13Lsun. Our study aims at quantifying the star-formation and AGN processes in these sources which recent results suggest have evolved strongly between the observed epoch and today. To do this, we study the mid-IR contribution of PAH emission, continuum, and extinction. About 3/4 of our sample are continuum- (i.e. AGN) dominated sources, but ~60% of these show PAH emission, suggesting the presence of star-formation activity. These sources have redder mid-IR colors than typical optically-selected quasars. About 25% of our sample have strong PAH emission, but none are likely to be pure starbursts as reflected in their relatively high 5um hot dust continua. However, their steep 30um-to-14um slopes suggest that star-formation might dominate the total infrared luminosity. Six of our z~2 sources have EW6.2>~0.3um and L_14um>~10^12Lsun (implying L_IR>~10^13Lsun). At these luminosities, such high EW6.2 ULIRGs do not exist in the local Universe. We find a median optical depth at 9.7um of =1.4. This is consistent with local IRAS-selected ULIRGs, but differs from early results on SCUBA-selected z~2 ULIRGs. Similar to local ULIRGs about 25% of our sample show extreme obscuration (tau_9.7>~3) suggesting buried nuclei. In general, we find that our sources are similar to local ULIRGs, but are an order of magnitude more luminous. It is not clear whether our z~2 ULIRGs are simply scaled-up versions of local ULIRGs, or subject to fundamentally different physical processes.

  18. Cosmological parameter constraints from SDSS luminous red galaxies: a new treatment of large-scale clustering

    E-Print Network [OSTI]

    Ariel G. Sanchez; M. Crocce; A. Cabre; C. M. Baugh; E. Gaztanaga

    2009-08-19T23:59:59.000Z

    We apply a new model for the spherically averaged correlation function at large pair separations to the measurement of the clustering of luminous red galaxies (LRGs) made from the SDSS by Cabre and Gaztanaga(2009). Our model takes into account the form of the BAO peak and the large scale shape of the correlation function. We perform a Monte Carlo Markov chain analysis for different combinations of datasets and for different parameter sets. When used in combination with a compilation of the latest CMB measurements, the LRG clustering and the latest supernovae results give constraints on cosmological parameters which are comparable and in remarkably good agreement, resolving the tension reported in some studies. The best fitting model in the context of a flat, Lambda-CDM cosmology is specified by Omega_m=0.261+-0.013, Omega_b=0.044+-0.001, n_s=0.96+-0.01, H_0=71.6+-1.2 km/s/Mpc and sigma_8=0.80+-0.02. If we allow the time-independent dark energy equation of state parameter to vary, we find results consistent with a cosmological constant at the 5% level using all data sets: w_DE=-0.97+-0.05. The large scale structure measurements by themselves can constrain the dark energy equation of state parameter to w_DE=-1.05+-0.15, independently of CMB or supernovae data. We do not find convincing evidence for an evolving equation of state. We provide a set of "extended distance priors" that contain the most relevant information from the CMB power spectrum and the shape of the LRG correlation function which can be used to constrain dark energy models and spatial curvature. Our model should provide an accurate description of the clustering even in much larger, forthcoming surveys, such as those planned with NASA's JDEM or ESA's Euclid mission.

  19. Gravitational wave background from sub-luminous GRBs: prospects for second and third generation detectors

    E-Print Network [OSTI]

    E. Howell; T. Regimbau; A. Corsi; D. Coward; R. Burman

    2010-08-24T23:59:59.000Z

    We assess the detection prospects of a gravitational wave background associated with sub-luminous gamma-ray bursts (SL-GRBs). We assume that the central engines of a significant proportion of these bursts are provided by newly born magnetars and consider two plausible GW emission mechanisms. Firstly, the deformation-induced triaxial GW emission from a newly born magnetar. Secondly, the onset of a secular bar-mode instability, associated with the long lived plateau observed in the X-ray afterglows of many gamma-ray bursts (Corsi & Meszaros 2009a). With regards to detectability, we find that the onset of a secular instability is the most optimistic scenario: under the hypothesis that SL-GRBs associated with secularly unstable magnetars occur at a rate of (48; 80)Gpc^{-3}yr^{-1} or greater, cross-correlation of data from two Einstein Telescopes (ETs) could detect the GW background associated to this signal with a signal-to-noise ratio of 3 or greater after 1 year of observation. Assuming neutron star spindown results purely from triaxial GW emissions, we find that rates of around (130;350)Gpc^{-3}yr^{-1} will be required by ET to detect the resulting GW background. We show that a background signal from secular instabilities could potentially mask a primordial GW background signal in the frequency range where ET is most sen- sitive. Finally, we show how accounting for cosmic metallicity evolution can increase the predicted signal-to-noise ratio for background signals associated with SL-GRBs.

  20. A new measurement of the bulk flow of X-ray luminous clusters of galaxies

    E-Print Network [OSTI]

    A. Kashlinsky; F. Atrio-Barandela; H. Ebeling; A. Edge; D. Kocevski

    2010-03-11T23:59:59.000Z

    We present new measurements of the large-scale bulk flows of galaxy clusters based on 5-year WMAP data and a significantly expanded X-ray cluster catalogue. Our method probes the flow via measurements of the kinematic Sunyaev-Zeldovich (SZ) effect produced by the hot gas in moving clusters. It computes the dipole in the cosmic microwave background (CMB) data at cluster pixels, which preserves the SZ component while integrating down other contributions. Our improved catalog of over 1,000 clusters enables us to further investigate possible systematic effects and, thanks to a higher median cluster redshift, allows us to measure the bulk flow to larger scales. We present a corrected error treatment and demonstrate that the more X-ray luminous clusters, while fewer in number, have much larger optical depth, resulting in a higher dipole and thus a more accurate flow measurement. This results in the observed correlation of the dipole derived at the aperture of zero monopole with the monopole measured over the cluster central regions. This correlation is expected if the dipole is produced by the SZ effect and cannot be caused by unidentified systematics (or primary cosmic microwave background anisotropies). We measure that the flow is consistent with approximately constant velocity out to at least 800 Mpc. The significance of the measured signal peaks around 500 Mpc, most likely because the contribution from more distant clusters becomes progressively more diluted by the WMAP beam. We can, however, at present not rule out that these more distant clusters simply contribute less to the overall motion.

  1. The Clustering of Luminous Red Galaxies in the Sloan Digital Sky Survey Imaging Data

    E-Print Network [OSTI]

    N. Padmanabhan; D. J. Schlegel; U. Seljak; A. Makarov; N. A. Bahcall; M. R. Blanton; J. Brinkmann; D. J. Eisenstein; D. P. Finkbeiner; J. E. Gunn; D. W. Hogg; Z. Ivezic; G. R. Knapp; J. Loveday; R. H. Lupton; R. C. Nichol; D. P. Schneider; M. A. Strauss; M. Tegmark; D. G. York

    2006-05-15T23:59:59.000Z

    We present the 3D real space clustering power spectrum of a sample of \\~600,000 luminous red galaxies (LRGs) measured by the Sloan Digital Sky Survey (SDSS), using photometric redshifts. This sample of galaxies ranges from redshift z=0.2 to 0.6 over 3,528 deg^2 of the sky, probing a volume of 1.5 (Gpc/h)^3, making it the largest volume ever used for galaxy clustering measurements. We measure the angular clustering power spectrum in eight redshift slices and combine these into a high precision 3D real space power spectrum from k=0.005 (h/Mpc) to k=1 (h/Mpc). We detect power on gigaparsec scales, beyond the turnover in the matter power spectrum, on scales significantly larger than those accessible to current spectroscopic redshift surveys. We also find evidence for baryonic oscillations, both in the power spectrum, as well as in fits to the baryon density, at a 2.5 sigma confidence level. The statistical power of these data to constrain cosmology is ~1.7 times better than previous clustering analyses. Varying the matter density and baryon fraction, we find \\Omega_M = 0.30 \\pm 0.03, and \\Omega_b/\\Omega_M = 0.18 \\pm 0.04, The detection of baryonic oscillations also allows us to measure the comoving distance to z=0.5; we find a best fit distance of 1.73 \\pm 0.12 Gpc, corresponding to a 6.5% error on the distance. These results demonstrate the ability to make precise clustering measurements with photometric surveys (abridged).

  2. The Environment on few Mpc scales of Infrared Luminous Galaxies at Redshifts z~1

    E-Print Network [OSTI]

    D. Marcillac; G. H. Rieke; C. Papovich; C. N. A. Willmer; B. J. Weiner; A. L. Coil; M. C. Cooper; B. F. Gerke; J. Woo; J. A. Newman; A. Georgakakis; E. S. Laird; K. Nandra; G. G. Fazio; J. -S. Huang; D. C. Koo

    2007-12-01T23:59:59.000Z

    We investigate the environment of infrared luminous galaxies (L$_{IR}$[8-1000 $\\mu $m$] >10^{11}$L$_{\\sun}$). We focus on the redshift range 0.7 $\\leq$ z $\\leq$ 1, where these galaxies dominate the star formation activity and play a significant role in galaxy evolution. We employ MIPS 24$\\mu$m data to identify infrared galaxies in the Extended Groth Strip (EGS). We use a local density indicator to probe the environment on few Mpc scales and a group member catalog, both of which make use of the DEEP2 spectroscopic redshift catalog, to quantify the environment of these galaxies. We find that the local environment of LIRGs and ULIRGs is intermediate between that of blue and red galaxies. LIRGs and ULIRGs avoid underdense environments and inhabit local environments that are more dense on average than those of other DEEP2 galaxies at similar redshifts. However, when the comparison sample of the non-IR DEEP2 galaxies is restricted to have the same range of stellar mass, color, or luminosity as the IR--galaxies, there is no longer any significant difference in environment; the IR-galaxies follow the same trends in the color-environment and luminosity-environment relations observed at z$\\sim$1. We also find that about 30% of the LIRGs and ULIRGs belong to groups, associated with a minimum dark matter halo of 6$\\times10^{12}$M$_{\\odot}$h$^{-1}$. The group members constitute 20 % of the sources responsible for the IR star formation rate density and comoving energy density at z$\\sim$1.

  3. Minimum Entangling Power is Close to Its Maximum

    E-Print Network [OSTI]

    Jianxin Chen; Zhengfeng Ji; David W Kribs; Bei Zeng

    2012-10-04T23:59:59.000Z

    Given a quantum gate $U$ acting on a bipartite quantum system, its maximum (average, minimum) entangling power is the maximum (average, minimum) entanglement generation with respect to certain entanglement measure when the inputs are restricted to be product states. In this paper, we mainly focus on the 'weakest' one, i.e., the minimum entangling power, among all these entangling powers. We show that, by choosing von Neumann entropy of reduced density operator or Schmidt rank as entanglement measure, even the 'weakest' entangling power is generically very close to its maximal possible entanglement generation. In other words, maximum, average and minimum entangling powers are generically close. We then study minimum entangling power with respect to other Lipschitiz-continuous entanglement measures and generalize our results to multipartite quantum systems. As a straightforward application, a random quantum gate will almost surely be an intrinsically fault-tolerant entangling device that will always transform every low-entangled state to near-maximally entangled state.

  4. NGC2613, 3198, 6503, 7184: Case studies against `maximum' disks

    E-Print Network [OSTI]

    B. Fuchs

    1998-12-02T23:59:59.000Z

    Decompositions of the rotation curves of NGC2613, 3198, 6505, and 7184 are analysed. For these galaxies the radial velocity dispersions of the stars have been measured and their morphology is clearly discernible. If the parameters of the decompositions are chosen according to the `maximum' disk hypothesis, the Toomre Q stability parameter is systematically less than one and the multiplicities of the spiral arms as expected from density wave theory are inconsitent with the observed morphologies of the galaxies. The apparent Q<1 instability, in particular, is a strong argument against the `maximum' disk hypothesis.

  5. When are microcircuits well-modeled by maximum entropy methods?

    E-Print Network [OSTI]

    2010-07-20T23:59:59.000Z

    POSTER PRESENTATION Open Access When are microcircuits well-modeled by maximum entropy methods? Andrea K Barreiro1*, Eric T Shea-Brown1, Fred M Rieke2,3, Julijana Gjorgjieva4 From Nineteenth Annual Computational Neuroscience Meeting: CNS*2010 San... Antonio, TX, USA. 24-30 July 2010 Recent experiments in retina and cortex have demon- strated that pairwise maximum entropy (PME) methods can approximate observed spiking patterns to a high degree of accuracy [1,2]. In this paper we examine...

  6. Valence quark distributions of the proton from maximum entropy approach

    E-Print Network [OSTI]

    Rong Wang; Xurong Chen

    2014-10-14T23:59:59.000Z

    We present an attempt of maximum entropy principle to determine valence quark distributions in the proton at very low resolution scale $Q_0^2$. The initial three valence quark distributions are obtained with limited dynamical information from quark model and QCD theory. Valence quark distributions from this method are compared to the lepton deep inelastic scattering data, and the widely used CT10 and MSTW08 data sets. The obtained valence quark distributions are consistent with experimental observations and the latest global fits of PDFs. Maximum entropy method is expected to be particularly useful in the case where relatively little information from QCD calculation is given.

  7. Valence quark distributions of the proton from maximum entropy approach

    E-Print Network [OSTI]

    Wang, Rong

    2014-01-01T23:59:59.000Z

    We present an attempt of maximum entropy principle to determine valence quark distributions in the proton at very low resolution scale $Q_0^2$. The initial three valence quark distributions are obtained with limited dynamical information from quark model and QCD theory. Valence quark distributions from this method are compared to the lepton deep inelastic scattering data, and the widely used CT10 and MSTW08 data sets. The obtained valence quark distributions are consistent with experimental observations and the latest global fits of PDFs. Maximum entropy method is expected to be particularly useful in the case where relatively little information from QCD calculation is given.

  8. Assessing complexity by means of maximum entropy models

    E-Print Network [OSTI]

    Chliamovitch, Gregor; Velasquez, Lino

    2014-01-01T23:59:59.000Z

    We discuss a characterization of complexity based on successive approximations of the probability density describing a system by means of maximum entropy methods, thereby quantifying the respective role played by different orders of interaction. This characterization is applied on simple cellular automata in order to put it in perspective with the usual notion of complexity for such systems based on Wolfram classes. The overlap is shown to be good, but not perfect. This suggests that complexity in the sense of Wolfram emerges as an intermediate regime of maximum entropy-based complexity, but also gives insights regarding the role of initial conditions in complexity-related issues.

  9. PSN J07285387+3349106 in NGC 2388: extremely rapidly declining luminous supernova

    E-Print Network [OSTI]

    Tsvetkov, D Yu; Pavlyuk, N N

    2015-01-01T23:59:59.000Z

    We present CCD BVRI photometry for PSN J07285387+3349106 in NGC 2388 collected from 2015 February 17 until March 17. Decaying by 3.6 mag in the R band in the first 20 days post-maximum, this object is among the fastest supernovae observed to date. The peak absolute R magnitude exceeds -18.7 and may be as high as -20.1.

  10. aom efficacy study: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    variations in poor localities influence the capacity for community efficacy. Through a multivariate analysis using 497 households in poor localities of Addis Ababa, we...

  11. When Crime Pays: Measuring Judicial Efficacy against Corruption in Brazil

    E-Print Network [OSTI]

    Ribeiro de Alencar, Carlos Higino; Gico, Ivo Jr.

    2010-01-01T23:59:59.000Z

    for now - crime pays in Brazil. Paginal5de27 ReferencesEfficacy against Corruption in Brazil Carlos Higino Ribeiroa widespread perception in Brazil that civil servants caught

  12. DOE Publishes Pricing and Efficacy Trend Analysis for Utility...

    Broader source: Energy.gov (indexed) [DOE]

    a new report, SSL Pricing and Efficacy Trend Analysis for Utility Program Planning. The report was created in response to requests from utilities and energy efficiency...

  13. Maximum stellar mass versus cluster membership number revisited

    E-Print Network [OSTI]

    Th. Maschberger; C. J. Clarke

    2008-09-05T23:59:59.000Z

    We have made a new compilation of observations of maximum stellar mass versus cluster membership number from the literature, which we analyse for consistency with the predictions of a simple random drawing hypothesis for stellar mass selection in clusters. Previously, Weidner and Kroupa have suggested that the maximum stellar mass is lower, in low mass clusters, than would be expected on the basis of random drawing, and have pointed out that this could have important implications for steepening the integrated initial mass function of the Galaxy (the IGIMF) at high masses. Our compilation demonstrates how the observed distribution in the plane of maximum stellar mass versus membership number is affected by the method of target selection; in particular, rather low n clusters with large maximum stellar masses are abundant in observational datasets that specifically seek clusters in the environs of high mass stars. Although we do not consider our compilation to be either complete or unbiased, we discuss the method by which such data should be statistically analysed. Our very provisional conclusion is that the data is not indicating any striking deviation from the expectations of random drawing.

  14. Maximum likelihood estimation of the equity Efstathios Avdis

    E-Print Network [OSTI]

    Kahana, Michael J.

    premium is usually estimated by taking the sample mean of stock returns and subtracting a measure the expected return on the aggregate stock market less the government bill rate, is of central importance an alternative esti- mator, based on maximum likelihood, that takes into account informa- tion contained

  15. STATE OF CALIFORNIA MAXIMUM RATED TOTAL COOLING CAPACITY

    E-Print Network [OSTI]

    /09) CALIFORNIA ENERGY COMMISSION INSTALLATION CERTIFICATE CF-6R-MECH-27-HERS Maximum Rated Total Cooling Capacity of the installed system (Btu/hr) 3b Sum of the ARI Rated Total Cooling Capacities of multiple systems installed Cooling Capacities of the installed cooling systems must be calculated and entered in row 3b. 4a MRTCC

  16. Maximum power tracking control scheme for wind generator systems

    E-Print Network [OSTI]

    Mena Lopez, Hugo Eduardo

    2008-10-10T23:59:59.000Z

    The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

  17. Maximum power tracking control scheme for wind generator systems

    E-Print Network [OSTI]

    Mena, Hugo Eduardo

    2009-05-15T23:59:59.000Z

    The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

  18. annual maximum water: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    annual maximum water First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 ORIGINAL PAPER The distribution of...

  19. BRANCH-CUT-AND-PROPAGATE FOR THE MAXIMUM k ...

    E-Print Network [OSTI]

    2011-03-16T23:59:59.000Z

    maximum k-colorable subgraph problem consists of selecting a k-color- able induced subgraph of ..... a symmetric subgroup Sp of Aut(G) acts on Vp for all p ? [s]. Let Vp = {vp. 1,...,vp qp. } ...... [9] J. Crawford, M. Ginsberg, E. Luks, and A. Roy.

  20. Renewable Energy Scheduling for Fading Channels with Maximum Power Constraint

    E-Print Network [OSTI]

    Greenberg, Albert

    Renewable Energy Scheduling for Fading Channels with Maximum Power Constraint Zhe Wang Electrical--In this paper, we develop efficient algorithm to obtain the optimal energy schedule for fading channel with energy harvesting. We assume that the side information of both the channel states and energy harvesting

  1. What is a Hurricane? Tropical system with maximum sustained

    E-Print Network [OSTI]

    Meyers, Steven D.

    Andrew-Category 4· Category 4 Hurricane - Winds 131-155 mph. Wall failures in homes and complete roofHurricane 101 #12;What is a Hurricane? · Tropical system with maximum sustained surface wind of 74 mph or greater. A hurricane is the worst and the strongest of all tropical systems. · Also known

  2. Individual Module Maximum Power Point Tracking for Thermoelectric Generator Systems

    E-Print Network [OSTI]

    Schaltz, Erik

    of Thermo Electric Generator (TEG) systems a power converter is often inserted between the TEG system that the TEG system produces the maximum power. However, if the conditions, e.g. temperature, health, age, etc find the best compromise of all modules. In order to increase the power production of the TEG system

  3. Efficiency Improvement of an IPMSM using Maximum Efficiency Operating Strategy

    E-Print Network [OSTI]

    Paderborn, Universität

    Efficiency Improvement of an IPMSM using Maximum Efficiency Operating Strategy Daniel Pohlenz. These are characterized by high efficiency and high torque as well as power density. The generation of reference currents that the MTPC method deviates considerably from the best efficiency under certain boundary conditions. The use

  4. Maximum power tracking control scheme for wind generator systems 

    E-Print Network [OSTI]

    Mena, Hugo Eduardo

    2009-05-15T23:59:59.000Z

    The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

  5. Maximum power tracking control scheme for wind generator systems 

    E-Print Network [OSTI]

    Mena Lopez, Hugo Eduardo

    2008-10-10T23:59:59.000Z

    The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor...

  6. MARTIN'S MAXIMUM AND TOWER FORCING SEAN COX AND MATTEO VIALE

    E-Print Network [OSTI]

    Viale, Matteo

    MARTIN'S MAXIMUM AND TOWER FORCING SEAN COX AND MATTEO VIALE Abstract. There are several examples, the Reflection Princi- ple (RP) implies that if I is a tower of ideals which concentrates on the class GIC1 of 1 [16], shows that if PFA+ or MM holds and there is an inaccessible cardinal, then there is a tower

  7. Retrocommissioning Case Study - Applying Building Selection Criteria for Maximum Results

    E-Print Network [OSTI]

    Luskay, L.; Haasl, T.; Irvine, L.; Frey, D.

    2002-01-01T23:59:59.000Z

    RETROCOMMISSIONING CASE STUDY ?Applying Building Selection Criteria for Maximum Results? Larry Luskay, Tudi Haasl, Linda Irvine Portland Energy Conservation, Inc. Portland, Oregon Donald Frey Architectural Energy Corporation Boulder.... The building was retrocommissioned by Portland Energy Conservation, Inc. (PECI), in conjunction with Architectural Energy Corporation (AEC). The building-specific goals were: 1) Obtain cost-effective energy savings from optimizing operation...

  8. The X-ray Properties of the Most-Luminous Quasars from the Sloan Digital Sky Survey

    E-Print Network [OSTI]

    D. W. Just; W. N. Brandt; O. Shemmer; A. T. Steffen; D. P. Schneider; G. Chartas; G. P. Garmire

    2007-05-21T23:59:59.000Z

    Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and XMM-Newton data, we study the X-ray properties of a representative sample of 59 of the most optically luminous quasars in the Universe (M_i~~-29.3 to -30.2) spanning a redshift range of z~~1.5-4.5. Our full sample consists of 32 quasars from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3) quasar catalog, two additional objects in the DR3 area that were missed by the SDSS selection criteria, and 25 comparably luminous quasars at z>~4. This is the largest X-ray study of such luminous quasars to date. By jointly fitting the X-ray spectra of our sample quasars, excluding radio-loud and broad absorption line (BAL) objects, we find a mean X-ray power-law photon index of Gamma=1.92^{+0.09}_{-0.08} and constrain any neutral intrinsic absorbing material to have a mean column density of N_Hluminous quasars. Our sample, excluding radio-loud and BAL quasars, has a mean X-ray-to-optical spectral slope of a_ox=-1.80+/-0.02, as well as no significant evolution of a_ox with redshift. We also comment upon the X-ray properties of a number of notable quasars, including an X-ray weak quasar with several strong narrow absorption-line systems, a mildly radio-loud BAL quasar, and a well-studied gravitationally lensed quasar.

  9. The DEEP2 Galaxy Redshift Survey: Discovery of Luminous, Metal-poor, Sta r-forming Galaxies at Redshifts z~0.7

    E-Print Network [OSTI]

    Carlos Hoyos; David C. Koo; Andrew C. Phillips; Christopher N. A. Willmer; Puragra Guhathakurta

    2005-10-31T23:59:59.000Z

    We have discovered a sample of 17 metal-poor, yet luminous, star-forming galaxies at redshifts z~0.7. They were selected from the initial phase of the DEEP2 survey of 3900 galaxies and the Team Keck Redshift Survey (TKRS) of 1536 galaxies as those showing the temperature-sensitive [OIII]l4363 auroral line. These rare galaxies have blue luminosities close to L*, high star formation rates of 5 to 12 solar masses per year, and oxygen abundances of 1/3 to 1/10 solar. They thus lie significantly off the luminosity-metallicity relation found previously for field galaxies with strong emission lines at redshifts z~0.7. The prior surveys relied on indirect, empirical calibrations of the R23 diagnostic and the assumption that luminous galaxies are not metal-poor. Our discovery suggests that this assumption is sometimes invalid. As a class, these newly-discovered galaxies are: (1) more metal-poor than common classes of bright emission-line galaxies at z~0.7 or at the present epoch; (2) comparable in metallicity to z~3 Lyman Break Galaxies but less luminous; and (3) comparable in metallicity to local metal-poor eXtreme Blue Compact Galaxies (XBCGs), but more luminous. Together, the three samples suggest that the most-luminous, metal-poor, compact galaxies become fainter over time.

  10. 3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation

    E-Print Network [OSTI]

    Sturzbecher-Hoehne, Manuel

    2012-01-01T23:59:59.000Z

    into Efficacious In Vivo Europium Decorporation Manuelinto Efficacious In Vivo Europium Decorporation Manuelinto Efficacious In Vivo Europium Decorporation Manuel

  11. Maximum Entropy Principle and the Higgs Boson Mass

    E-Print Network [OSTI]

    Alves, Alexandre; da Silva, Roberto

    2014-01-01T23:59:59.000Z

    A successful connection between Higgs boson decays and the Maximum Entropy Principle is presented. Based on the information theory inference approach we determine the Higgs boson mass as $M_H= 125.04\\pm 0.25$ GeV, a value fully compatible to the LHC measurement. This is straightforwardly obtained by taking the Higgs boson branching ratios as the target probability distributions of the inference, without any extra assumptions beyond the Standard Model. Yet, the principle can be a powerful tool in the construction of any model affecting the Higgs sector. We give, as an example, the case where the Higgs boson has an extra invisible decay channel. Our findings suggest that a system of Higgs bosons undergoing a collective decay to Standard Model particles is among the most fundamental ones where the Maximum Entropy Principle applies.

  12. Maximum Entropy Principle and the Higgs Boson Mass

    E-Print Network [OSTI]

    Alexandre Alves; Alex G. Dias; Roberto da Silva

    2014-11-18T23:59:59.000Z

    A successful connection between Higgs boson decays and the Maximum Entropy Principle is presented. Based on the information theory inference approach we determine the Higgs boson mass as $M_H= 125.04\\pm 0.25$ GeV, a value fully compatible to the LHC measurement. This is straightforwardly obtained by taking the Higgs boson branching ratios as the target probability distributions of the inference, without any extra assumptions beyond the Standard Model. Yet, the principle can be a powerful tool in the construction of any model affecting the Higgs sector. We give, as an example, the case where the Higgs boson has an extra invisible decay channel. Our findings suggest that a system of Higgs bosons undergoing a collective decay to Standard Model particles is among the most fundamental ones where the Maximum Entropy Principle applies.

  13. A redshift - observation-time relation for gamma-ray bursts: evidence of a distinct sub-luminous population

    E-Print Network [OSTI]

    E. J. Howell; D. M. Coward

    2013-02-19T23:59:59.000Z

    We show how the redshift and peak-flux distributions of gamma-ray bursts (GRBs) have an observation time dependence that can be used to discriminate between different burst populations. We demonstrate how observation time relations can be derived from the standard integral distributions and that they can differentiate between GRB populations detected by both the BATSE and \\emph{Swift} satellites. Using \\emph{Swift} data we show that a redshift--observation-time relation (log\\,$Z$\\,--\\,log\\,$T$) is consistent with both a peak-flux\\,--\\,observation time relation (log\\,$P$\\,--\\,log\\,$T$) and a standard log\\,$N$\\,--\\,log\\,$P$ brightness distribution. As the method depends only on rarer small-$z$ events, it is invariant to high-$z$ selection effects. We use the log\\,$Z$\\,--\\,log\\,$T$ relation to show that sub-luminous GRBs are a distinct population occurring at a higher rate of order $150^{+180}_{-90} \\mathrm{Gpc}^{-3}\\mathrm{yr}^{-1}$. Our analysis suggests that GRB 060505 -- a relatively nearby GRB observed without any associated supernova -- is consistent with a sub-luminous population of bursts. Finally, we suggest that our relations can be used as a consistency test for some of the proposed GRB spectral energy correlations.

  14. Major Mergers Host the Most Luminous Red Quasars at z ~ 2: A Hubble Space Telescope WFC3/IR Study

    E-Print Network [OSTI]

    Glikman, Eilat; Mailly, Madeline; Schawinski, Kevin; Urry, C M; Lacy, M

    2015-01-01T23:59:59.000Z

    We used the Hubble Space Telescope WFC3 near-infrared camera to image the host galaxies of a sample of eleven luminous, dust-reddened quasars at z ~ 2 -- the peak epoch of black hole growth and star formation in the Universe -- to test the merger-driven picture for the co-evolution of galaxies and their nuclear black holes. The red quasars come from the FIRST+2MASS red quasar survey and a newer, deeper, UKIDSS+FIRST sample. These dust-reddened quasars are the most intrinsically luminous quasars in the Universe at all redshifts, and may represent the dust-clearing transitional phase in the merger-driven black hole growth scenario. Probing the host galaxies in rest-frame visible light, the HST images reveal that 8/10 of these quasars have actively merging hosts, while one source is reddened by an intervening lower redshift galaxy along the line-of-sight. We study the morphological properties of the quasar hosts using parametric Sersic fits as well as the non-parametric estimators (Gini coefficient, M_{20} and a...

  15. X-ray luminous radio-quiet high redshift QSOs in the ROSAT All-Sky Survey

    E-Print Network [OSTI]

    Xue-Bing Wu; Norbert Bade; Volker Beckmann

    1999-04-19T23:59:59.000Z

    X-ray luminous radio-quiet high redshift QSOs are rare and can be used for the investigation of several important astronomical questions. We have conducted a large area survey for radio-quiet high redshift QSOs in the ROSAT All-Sky Survey, from which QSO candidates are selected using the digitized objective prism spectra from the Hamburg Quasar Survey. The 22 candidates with Galactic latitudes larger than $35^o$ were observed with the 2.16m telescope at Xinglong station of Beijing Astronomical Observatory. Among the 19 new QSOs in our sample, six are radio-quiet QSOs with redshifts larger than 1.3 and three of them have redshifts larger than 2. Thus we have doubled the number of known X-ray luminous, radio-quiet high redshift QSOs in the surveyed sky area. The distribution of $f_{1.4GHz}/f_{1keV}$ of radio-loud and radio-quiet QSOs in this area shows two well separated peaks. This can be taken as an evidence for different emission mechanisms of the observed X-rays in the two subgroups.

  16. Line Identifications of Type I Supernova Spectra Revisited: Detections of Unburned Hydrogen in Type Ib, Ic, and More Luminous Events

    E-Print Network [OSTI]

    Parrent, J T; Soderberg, A M; Parthasarathy, M

    2015-01-01T23:59:59.000Z

    The spectrum of a supernova results from a complex array of overlapping atomic signatures that are sensitive to the composition and state of unburned and freshly synthesized material. Most theoretical models indicate that observed features near 6000-6300 Angstroms in type I spectra are due to more than a single component of Si II l6355, if at all for poorly matched Ib, Ic, and super-luminous supernovae; an interpretation of Si II l6355 works for nominal 6150 Angstrom absorption features of all type Ia supernovae during the first month of free expansion while the same interpretation has not been successful for a majority of type Ib and Ic. Instead, canonical 6250 Angstrom absorption features of type Ib and Ic spectra are likely shaped primarily by faint signatures of Halpha. Meanwhile, we also find the identification of Si II l6355 in the spectra of broad-lined Ic and super-luminous events of type I/R is less convincing in spite of numerous model spectra used to show otherwise. Here we argue a more likely expl...

  17. Max '91: flare research at the next solar maximum

    SciTech Connect (OSTI)

    Dennis, B.; Canfield, R.; Bruner, M.; Emslie, G.; Hildner, E.; Hudson, H.; Hurford, G.; Lin, R.; Novick, R.; Tarbell, T.

    1988-01-01T23:59:59.000Z

    To address the central scientific questions surrounding solar flares, coordinated observations of electromagnetic radiation and energetic particles must be made from spacecraft, balloons, rockets, and ground-based observatories. A program to enhance capabilities in these areas in preparation for the next solar maximum in 1991 is recommended. The major scientific issues are described, and required observations and coordination of observations and analyses are detailed. A program plan and conceptual budgets are provided.

  18. Maximum Entry and Mandatory Separation Ages for Certain Security Employees

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2001-10-11T23:59:59.000Z

    The policy establishes the DOE policy on maximum entry and mandatory separation ages for primary or secondary positions covered under special statutory retirement provisions and for those employees whose primary duties are the protection of officials of the United States against threats to personal safety or the investigation, apprehension, and detention of individuals suspected or convicted of offenses against the criminal laws of the United States. Admin Chg 1, dated 12-1-11, cancels DOE P 310.1.

  19. Maximum entropy method for reconstruction of the CMB images

    E-Print Network [OSTI]

    A. T. Bajkova

    2002-05-21T23:59:59.000Z

    We propose a new approach for the accurate reconstruction of cosmic microwave background distributions from observations containing in addition to the primary fluctuations the radiation from unresolved extragalactic point sources and pixel noise. The approach uses some effective realizations of the well-known maximum entropy method and principally takes into account {\\it a priori} information about finiteness and spherical symmetry of the power spectrum of the CMB satisfying the Gaussian statistics.

  20. Maximum total organic carbon limit for DWPF melter feed

    SciTech Connect (OSTI)

    Choi, A.S.

    1995-03-13T23:59:59.000Z

    DWPF recently decided to control the potential flammability of melter off-gas by limiting the total carbon content in the melter feed and maintaining adequate conditions for combustion in the melter plenum. With this new strategy, all the LFL analyzers and associated interlocks and alarms were removed from both the primary and backup melter off-gas systems. Subsequently, D. Iverson of DWPF- T{ampersand}E requested that SRTC determine the maximum allowable total organic carbon (TOC) content in the melter feed which can be implemented as part of the Process Requirements for melter feed preparation (PR-S04). The maximum TOC limit thus determined in this study was about 24,000 ppm on an aqueous slurry basis. At the TOC levels below this, the peak concentration of combustible components in the quenched off-gas will not exceed 60 percent of the LFL during off-gas surges of magnitudes up to three times nominal, provided that the melter plenum temperature and the air purge rate to the BUFC are monitored and controlled above 650 degrees C and 220 lb/hr, respectively. Appropriate interlocks should discontinue the feeding when one or both of these conditions are not met. Both the magnitude and duration of an off-gas surge have a major impact on the maximum TOC limit, since they directly affect the melter plenum temperature and combustion. Although the data obtained during recent DWPF melter startup tests showed that the peak magnitude of a surge can be greater than three times nominal, the observed duration was considerably shorter, on the order of several seconds. The long surge duration assumed in this study has a greater impact on the plenum temperature than the peak magnitude, thus making the maximum TOC estimate conservative. Two models were used to make the necessary calculations to determine the TOC limit.

  1. Occam's Razor Cuts Away the Maximum Entropy Principle

    E-Print Network [OSTI]

    Rudnicki, ?ukasz

    2014-01-01T23:59:59.000Z

    I show that the maximum entropy principle can be replaced by a more natural assumption, that there exists a phenomenological function of entropy consistent with the microscopic model. The requirement of existence provides then a unique construction of the related probability density. I conclude the letter with an axiomatic formulation of the notion of entropy, which is suitable for exploration of the non-equilibrium phenomena.

  2. PNNL: A Supervised Maximum Entropy Approach to Word Sense Disambiguation

    SciTech Connect (OSTI)

    Tratz, Stephen C.; Sanfilippo, Antonio P.; Gregory, Michelle L.; Chappell, Alan R.; Posse, Christian; Whitney, Paul D.

    2007-06-23T23:59:59.000Z

    In this paper, we described the PNNL Word Sense Disambiguation system as applied to the English All-Word task in Se-mEval 2007. We use a supervised learning approach, employing a large number of features and using Information Gain for dimension reduction. Our Maximum Entropy approach combined with a rich set of features produced results that are significantly better than baseline and are the highest F-score for the fined-grained English All-Words subtask.

  3. Some interesting consequences of the maximum entropy production principle

    SciTech Connect (OSTI)

    Martyushev, L. M. [Russian Academy of Sciences, Institute of Industrial Ecology, Ural Division (Russian Federation)], E-mail: mlm@ecko.uran.ru

    2007-04-15T23:59:59.000Z

    Two nonequilibrium phase transitions (morphological and hydrodynamic) are analyzed by applying the maximum entropy production principle. Quantitative analysis is for the first time compared with experiment. Nonequilibrium crystallization of ice and laminar-turbulent flow transition in a circular pipe are examined as examples of morphological and hydrodynamic transitions, respectively. For the latter transition, a minimum critical Reynolds number of 1200 is predicted. A discussion of this important and interesting result is presented.

  4. Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensembles out-of-equilibrium

    E-Print Network [OSTI]

    Crooks, Gavin E.

    2006-01-01T23:59:59.000Z

    1957). J. Skilling, in Maximum Entropy and Bayesian Methods,45–52. J. Skilling, in Maximum Entropy and Bayesian Methods,e C. C. Rodriguez, in Maximum Entropy and Bayesian Methods,

  5. Deriving the continuity of maximum-entropy basis functions via variational analysis

    E-Print Network [OSTI]

    Sukumar, N.; Wets, R. J. -B.

    2007-01-01T23:59:59.000Z

    and V. J. DellaPietra, A maximum entropy approach to naturalJ. and R. K. Bryan, Maximum entropy image reconstruction:Heidelberg, Continuity of maximum-entropy basis functions p

  6. Better Nonlinear Models from Noisy Data: Attractors with Maximum Likelihood

    E-Print Network [OSTI]

    Patrick E. McSharry; Leonard A. Smith

    1999-11-30T23:59:59.000Z

    A new approach to nonlinear modelling is presented which, by incorporating the global behaviour of the model, lifts shortcomings of both least squares and total least squares parameter estimates. Although ubiquitous in practice, a least squares approach is fundamentally flawed in that it assumes independent, normally distributed (IND) forecast errors: nonlinear models will not yield IND errors even if the noise is IND. A new cost function is obtained via the maximum likelihood principle; superior results are illustrated both for small data sets and infinitely long data streams.

  7. Application of Maximum Entropy Method to Dynamical Fermions

    E-Print Network [OSTI]

    Jonathan Clowser; Costas Strouthos

    2001-10-16T23:59:59.000Z

    The Maximum Entropy Method is applied to dynamical fermion simulations of the (2+1)-dimensional Nambu-Jona-Lasinio model. This model is particularly interesting because at T=0 it has a broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are resonances, and hence the simple pole assumption of traditional fitting procedures breaks down. We present results extracted from simulations on large lattices for the spectral functions of the elementary fermion, the pion, the sigma, the massive pseudoscalar meson and the symmetric phase resonances.

  8. Improving predictability of time series using maximum entropy methods

    E-Print Network [OSTI]

    Gregor Chliamovitch; Alexandre Dupuis; Bastien Chopard; Anton Golub

    2014-11-28T23:59:59.000Z

    We discuss how maximum entropy methods may be applied to the reconstruction of Markov processes underlying empirical time series and compare this approach to usual frequency sampling. It is shown that, at least in low dimension, there exists a subset of the space of stochastic matrices for which the MaxEnt method is more efficient than sampling, in the sense that shorter historical samples have to be considered to reach the same accuracy. Considering short samples is of particular interest when modelling smoothly non-stationary processes, for then it provides, under some conditions, a powerful forecasting tool. The method is illustrated for a discretized empirical series of exchange rates.

  9. Reducing Degeneracy in Maximum Entropy Models of Networks

    E-Print Network [OSTI]

    Horvát, Szabolcs; Toroczkai, Zoltán

    2014-01-01T23:59:59.000Z

    Based on Jaynes's maximum entropy principle, exponential random graphs provide a family of principled models that allow the prediction of network properties as constrained by empirical data. However, their use is often hindered by the degeneracy problem characterized by spontaneous symmetry-breaking, where predictions simply fail. Here we show that degeneracy appears when the corresponding density of states function is not log-concave. We propose a solution to the degeneracy problem for a large class of models by exploiting the nonlinear relationships between the constrained measures to convexify the domain of the density of states. We demonstrate the effectiveness of the method on examples, including on Zachary's karate club network data.

  10. Improving predictability of time series using maximum entropy methods

    E-Print Network [OSTI]

    Chliamovitch, Gregor; Chopard, Bastien; Golub, Anton

    2014-01-01T23:59:59.000Z

    We discuss how maximum entropy methods may be applied to the reconstruction of Markov processes underlying empirical time series and compare this approach to usual frequency sampling. It is shown that, at least in low dimension, there exists a subset of the space of stochastic matrices for which the MaxEnt method is more efficient than sampling, in the sense that shorter historical samples have to be considered to reach the same accuracy. Considering short samples is of particular interest when modelling smoothly non-stationary processes, for then it provides, under some conditions, a powerful forecasting tool. The method is illustrated for a discretized empirical series of exchange rates.

  11. Excited nucleon spectrum from lattice QCD with maximum entropy method

    E-Print Network [OSTI]

    K. Sasaki; S. Sasaki; T. Hatsuda; M. Asakawa

    2003-09-29T23:59:59.000Z

    We study excited states of the nucleon in quenched lattice QCD with the spectral analysis using the maximum entropy method. Our simulations are performed on three lattice sizes $16^3\\times 32$, $24^3\\times 32$ and $32^3\\times 32$, at $\\beta=6.0$ to address the finite volume issue. We find a significant finite volume effect on the mass of the Roper resonance for light quark masses. After removing this systematic error, its mass becomes considerably reduced toward the direction to solve the level order puzzle between the Roper resonance $N'(1440)$ and the negative-parity nucleon $N^*(1535)$.

  12. Probing stellar winds and accretion physics in high-mass X-ray binaries and ultra-luminous X-ray sources with LOFT

    E-Print Network [OSTI]

    Orlandini, M; Zampieri, L; Bozzo, E; Baykal, A; Blay, P; Chernyakova, M; Corbet, R; D'Aì, A; Enoto, T; Ferrigno, C; Finger, M; Klochkov, D; Kreykenbohm, I; Inam, S C; Jenke, P; Masetti, N; Manousakis, A; Mihara, T; Paul, B; Postnov, K; Reig, P; Romano, P; Santangelo, A; Shakura, N; Staubert, R; Torrejón, J M; Walter, R; Wilms, J; Wilson-Hodge, C

    2015-01-01T23:59:59.000Z

    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of high-mass X-ray binaries and ultra-luminous X-ray sources. For a summary, we refer to the paper.

  13. Efficacy of 45 lm/W Achieved in White OLED

    Broader source: Energy.gov [DOE]

    Universal Display Corporation (UDC) successfully demonstrated an all phosphorescent white organic light emitting diode (WOLED™) with a power efficacy of 45 lm/W at 1,000 cd/m2. This high-efficacy device was enabled by lowering the device operating voltage, increasing the outcoupling efficiency to ~40% from ~20%, and by incorporating highly efficient phosphorescent emitters that are capable of converting nearly all current passing through a WOLED into light.

  14. Probable maximum flood control; Yucca Mountain Site Characterization Project

    SciTech Connect (OSTI)

    DeGabriele, C.E.; Wu, C.L. [Bechtel National, Inc., San Francisco, CA (United States)

    1991-11-01T23:59:59.000Z

    This study proposes preliminary design concepts to protect the waste-handling facilities and all shaft and ramp entries to the underground from the probable maximum flood (PMF) in the current design configuration for the proposed Nevada Nuclear Waste Storage Investigation (NNWSI) repository protection provisions were furnished by the United States Bureau of Reclamation (USSR) or developed from USSR data. Proposed flood protection provisions include site grading, drainage channels, and diversion dikes. Figures are provided to show these proposed flood protection provisions at each area investigated. These areas are the central surface facilities (including the waste-handling building and waste treatment building), tuff ramp portal, waste ramp portal, men-and-materials shaft, emplacement exhaust shaft, and exploratory shafts facility.

  15. Maximum Margin Clustering for State Decomposition of Metastable Systems

    E-Print Network [OSTI]

    Wu, Hao

    2015-01-01T23:59:59.000Z

    When studying a metastable dynamical system, a prime concern is how to decompose the phase space into a set of metastable states. Unfortunately, the metastable state decomposition based on simulation or experimental data is still a challenge. The most popular and simplest approach is geometric clustering which is developed based on the classical clustering technique. However, the prerequisites of this approach are: (1) data are obtained from simulations or experiments which are in global equilibrium and (2) the coordinate system is appropriately selected. Recently, the kinetic clustering approach based on phase space discretization and transition probability estimation has drawn much attention due to its applicability to more general cases, but the choice of discretization policy is a difficult task. In this paper, a new decomposition method designated as maximum margin metastable clustering is proposed, which converts the problem of metastable state decomposition to a semi-supervised learning problem so that...

  16. Efficiency at maximum power of a chemical engine

    E-Print Network [OSTI]

    Hooyberghs, Hans; Salazar, Alberto; Indekeu, Joseph O; Broeck, Christian Van den

    2013-01-01T23:59:59.000Z

    A cyclically operating chemical engine is considered that converts chemical energy into mechanical work. The working fluid is a gas of finite-sized spherical particles interacting through elastic hard collisions. For a generic transport law for particle uptake and release, the efficiency at maximum power $\\eta$ takes the form 1/2+c\\Delta \\mu + O(\\Delta \\mu^2), with 1/2 a universal constant and $\\Delta \\mu$ the chemical potential difference between the particle reservoirs. The linear coefficient c is zero for engines featuring a so-called left/right symmetry or particle fluxes that are antisymmetric in the applied chemical potential difference. Remarkably, the leading constant in $\\eta$ is non-universal with respect to an exceptional modification of the transport law. For a nonlinear transport model we obtain \\eta = 1/(\\theta +1), with \\theta >0 the power of $\\Delta \\mu$ in the transport equation

  17. Reduction in maximum time uncertainty of paired time signals

    DOE Patents [OSTI]

    Theodosiou, George E. (West Chicago, IL); Dawson, John W. (Clarendon Hills, IL)

    1983-01-01T23:59:59.000Z

    Reduction in the maximum time uncertainty (t.sub.max -t.sub.min) of a series of paired time signals t.sub.1 and t.sub.2 varying between two input terminals and representative of a series of single events where t.sub.1 .ltoreq.t.sub.2 and t.sub.1 +t.sub.2 equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t.sub.min) of the first signal t.sub.1 closer to t.sub.max and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20-800.

  18. Reduction in maximum time uncertainty of paired time signals

    DOE Patents [OSTI]

    Theodosiou, G.E.; Dawson, J.W.

    1983-10-04T23:59:59.000Z

    Reduction in the maximum time uncertainty (t[sub max]--t[sub min]) of a series of paired time signals t[sub 1] and t[sub 2] varying between two input terminals and representative of a series of single events where t[sub 1][<=]t[sub 2] and t[sub 1]+t[sub 2] equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t[sub min]) of the first signal t[sub 1] closer to t[sub max] and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20--800. 6 figs.

  19. Reduction in maximum time uncertainty of paired time signals

    DOE Patents [OSTI]

    Theodosiou, G.E.; Dawson, J.W.

    1981-02-11T23:59:59.000Z

    Reduction in the maximum time uncertainty (t/sub max/ - t/sub min/) of a series of paired time signals t/sub 1/ and t/sub 2/ varying between two input terminals and representative of a series of single events where t/sub 1/ less than or equal to t/sub 2/ and t/sub 1/ + t/sub 2/ equals a constant, is carried out with a circuit utilizing a combination of OR and AND gates as signal selecting means and one or more time delays to increase the minimum value (t/sub min/) of the first signal t/sub 1/ closer to t/sub max/ and thereby reduce the difference. The circuit may utilize a plurality of stages to reduce the uncertainty by factors of 20 to 800.

  20. Improved Maximum Entropy Analysis with an Extended Search Space

    E-Print Network [OSTI]

    Alexander Rothkopf

    2013-01-07T23:59:59.000Z

    The standard implementation of the Maximum Entropy Method (MEM) follows Bryan and deploys a Singular Value Decomposition (SVD) to limit the dimensionality of the underlying solution space apriori. Here we present arguments based on the shape of the SVD basis functions and numerical evidence from a mock data analysis, which show that the correct Bayesian solution is not in general recovered with this approach. As a remedy we propose to extend the search basis systematically, which will eventually recover the full solution space and the correct solution. In order to adequately approach problems where an exponentially damped kernel is used, we provide an open-source implementation, using the C/C++ language that utilizes high precision arithmetic adjustable at run-time. The LBFGS algorithm is included in the code in order to attack problems without the need to resort to a particular search space restriction.

  1. Quantum maximum entropy principle for a system of identical particles

    SciTech Connect (OSTI)

    Trovato, M. [Dipartimento di Matematica, Universita di Catania, Viale A. Doria, 95125 Catania (Italy); Reggiani, L. [Dipartimento di Ingegneria dell' Innovazione and CNISM, Universita del Salento, Via Arnesano s/n, 73100 Lecce (Italy)

    2010-02-15T23:59:59.000Z

    By introducing a functional of the reduced density matrix, we generalize the definition of a quantum entropy which incorporates the indistinguishability principle of a system of identical particles. With the present definition, the principle of quantum maximum entropy permits us to solve the closure problem for a quantum hydrodynamic set of balance equations corresponding to an arbitrary number of moments in the framework of extended thermodynamics. The determination of the reduced Wigner function for equilibrium and nonequilibrium conditions is found to become possible only by assuming that the Lagrange multipliers can be expanded in powers of (Planck constant/2pi){sup 2}. Quantum contributions are expressed in powers of (Planck constant/2pi){sup 2} while classical results are recovered in the limit (Planck constant/2pi)->0.

  2. Savannah River Site radioiodine atmospheric releases and offsite maximum doses

    SciTech Connect (OSTI)

    Marter, W.L.

    1990-11-01T23:59:59.000Z

    Radioisotopes of iodine have been released to the atmosphere from the Savannah River Site since 1955. The releases, mostly from the 200-F and 200-H Chemical Separations areas, consist of the isotopes, I-129 and 1-131. Small amounts of 1-131 and 1-133 have also been released from reactor facilities and the Savannah River Laboratory. This reference memorandum was issued to summarize our current knowledge of releases of radioiodines and resultant maximum offsite doses. This memorandum supplements the reference memorandum by providing more detailed supporting technical information. Doses reported in this memorandum from consumption of the milk containing the highest I-131 concentration following the 1961 1-131 release incident are about 1% higher than reported in the reference memorandum. This is the result of using unrounded 1-131 concentrations of I-131 in milk in this memo. It is emphasized here that this technical report does not constitute a dose reconstruction in the same sense as the dose reconstruction effort currently underway at Hanford. This report uses existing published data for radioiodine releases and existing transport and dosimetry models.

  3. Maximum gravitational-wave energy emissible in magnetar flares

    E-Print Network [OSTI]

    Alessandra Corsi; Benjamin J. Owen

    2011-02-16T23:59:59.000Z

    Recent searches of gravitational-wave (GW) data raise the question of what maximum GW energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (\\sim 10^{49} erg) predicted so far come from a model [K. Ioka, Mon. Not. Roy. Astron. Soc. 327, 639 (2001)] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 10^{48}-10^{49} erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

  4. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    SciTech Connect (OSTI)

    Don Augenstein

    2001-02-01T23:59:59.000Z

    The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

  5. Maximum Entropy Analysis of the Spectral Functions in Lattice QCD

    E-Print Network [OSTI]

    M. Asakawa; T. Hatsuda; Y. Nakahara

    2001-02-26T23:59:59.000Z

    First principle calculation of the QCD spectral functions (SPFs) based on the lattice QCD simulations is reviewed. Special emphasis is placed on the Bayesian inference theory and the Maximum Entropy Method (MEM), which is a useful tool to extract SPFs from the imaginary-time correlation functions numerically obtained by the Monte Carlo method. Three important aspects of MEM are (i) it does not require a priori assumptions or parametrizations of SPFs, (ii) for given data, a unique solution is obtained if it exists, and (iii) the statistical significance of the solution can be quantitatively analyzed. The ability of MEM is explicitly demonstrated by using mock data as well as lattice QCD data. When applied to lattice data, MEM correctly reproduces the low-energy resonances and shows the existence of high-energy continuum in hadronic correlation functions. This opens up various possibilities for studying hadronic properties in QCD beyond the conventional way of analyzing the lattice data. Future problems to be studied by MEM in lattice QCD are also summarized.

  6. Improved Maximum Entropy Method with an Extended Search Space

    E-Print Network [OSTI]

    Alexander Rothkopf

    2012-08-25T23:59:59.000Z

    We report on an improvement to the implementation of the Maximum Entropy Method (MEM). It amounts to departing from the search space obtained through a singular value decomposition (SVD) of the Kernel. Based on the shape of the SVD basis functions we argue that the MEM spectrum for given $N_\\tau$ data-points $D(\\tau)$ and prior information $m(\\omega)$ does not in general lie in this $N_\\tau$ dimensional singular subspace. Systematically extending the search basis will eventually recover the full search space and the correct extremum. We illustrate this idea through a mock data analysis inspired by actual lattice spectra, to show where our improvement becomes essential for the success of the MEM. To remedy the shortcomings of Bryan's SVD prescription we propose to use the real Fourier basis, which consists of trigonometric functions. Not only does our approach lead to more stable numerical behavior, as the SVD is not required for the determination of the basis functions, but also the resolution of the MEM becomes independent from the position of the reconstructed peaks.

  7. Maximum entropy detection of planets around active stars

    E-Print Network [OSTI]

    Petit, P; Hébrard, E; Morin, J; Folsom, C P; Böhm, T; Boisse, I; Borgniet, S; Bouvier, J; Delfosse, X; Hussain, G; Jeffers, S V; Marsden, S C; Barnes, J R

    2015-01-01T23:59:59.000Z

    (shortened for arXiv) We aim to progress towards more efficient exoplanet detection around active stars by optimizing the use of Doppler Imaging in radial velocity measurements. We propose a simple method to simultaneously extract a brightness map and a set of orbital parameters through a tomographic inversion technique derived from classical Doppler mapping. Based on the maximum entropy principle, the underlying idea is to determine the set of orbital parameters that minimizes the information content of the resulting Doppler map. We carry out a set of numerical simulations to perform a preliminary assessment of the robustness of our method, using an actual Doppler map of the very active star HR 1099 to produce a realistic synthetic data set for various sets of orbital parameters of a single planet in a circular orbit. Using a simulated time-series of 50 line profiles affected by a peak-to-peak activity jitter of 2.5 km/s, we are able in most cases to recover the radial velocity amplitude, orbital phase and o...

  8. The quest for Type 2 quasars: Chandra observations of luminous obscured quasars in the Sloan Digital Sky Survey

    E-Print Network [OSTI]

    C. Vignali; D. M. Alexander; A. Comastri

    2006-09-04T23:59:59.000Z

    We report on new Chandra exploratory observations of six candidate Type 2 quasars at z=0.49-0.73 selected among the most [OIII] luminous emitters from the Sloan Digital Sky Survey (SDSS). Under the assumption that [OIII] is a proxy for the intrinsic luminosity of the central source, their predicted rest-frame X-ray luminosities are L(2-10keV)~10^45 erg/s. For two of the targets, the photon statistics are good enough to allow for basic X-ray spectral analyses, which indicate the presence of intrinsic absorption (~10^{22-23} cm^-2) and luminous X-ray emission (L_X>10^44 erg/s). Of the remaining four targets, two are detected with only a few (3-6) X-ray counts, and two are undetected by Chandra. If these four sources have the large intrinsic X-ray luminosities predicted by the [OIII] emission, then their nuclei must be heavily obscured (N_H>few 10^23 cm^-2) and some might be Compton thick (N_H>1.5 10^24 cm^-2). We also present the results for two Type 2 quasar candidates serendipitously lying in the fields of the Chandra targets, and provide an up-to-date compilation of the X-ray properties of eight additional SDSS Type 2 quasars from archival Chandra and XMM-Newton observations (five with moderate-quality X-ray data). The combined sample of 16 SDSS Type 2 quasars (10 X-ray detections) provides further evidence that a considerable fraction of optically selected Type 2 quasars are obscured in the X-ray band (at least all the objects with moderate-quality X-ray spectra), lending further support to the findings presented in Vignali, Alexander and Comastri (2004a) and unification schemes of Active Galactic Nuclei, and confirms the reliability of [OIII] emission in predicting the X-ray emission in obscured quasars.

  9. PHOTOMETRIC REDSHIFTS AND SYSTEMATIC VARIATIONS IN THE SPECTRAL ENERGY DISTRIBUTIONS OF LUMINOUS RED GALAXIES FROM SDSS DR7

    SciTech Connect (OSTI)

    Greisel, N.; Seitz, S.; Bender, R.; Saglia, R. P.; Snigula, J. [Universitaets-Sternwarte Muenchen, Ludwig-Maximilians-Universitaet Muenchen, Scheinerstr. 1, D-81679 Muenchen (Germany); Drory, N., E-mail: greisel@usm.lmu.de [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany)

    2013-05-10T23:59:59.000Z

    We describe the construction of a template set of spectral energy distributions (SEDs) for the estimation of photometric redshifts of luminous red galaxies (LRGs) with a Bayesian template fitting method. By examining the color properties of several publicly available SED sets within a redshift range of 0 < z {approx}< 0.5 and comparing them to Sloan Digital Sky Survey (SDSS) Data Release 7 data, we show that only some of the investigated SEDs approximately match the colors of the LRG data throughout the redshift range, however not at the quantitative level required for precise photometric redshifts. This is because the SEDs of galaxies evolve with time (and redshift) and because at fixed redshift the LRG colors have an intrinsic spread such that they cannot be matched by one SED only. We generate new SEDs by superposing model SEDs of composite stellar populations with a burst model, allowing both components to be reddened by dust, in order to match the data in five different redshift bins. We select a set of SEDs which represents the LRG data in color space within five redshift bins, thus defining our new SED template set for photometric redshift estimates. The results we obtain with the new template set and our Bayesian template fitting photometric redshift code (PhotoZ) are nearly unbiased, with a scatter of {sigma}{sub {Delta}z} = 0.027 (including outliers), a fraction of catastrophic outliers (|z{sub phot} - z{sub spec}|/(1 + z{sub spec}) > 0.15) of {eta} = 0.12%, and a normalized median absolute rest frame deviation (NMAD) of {sigma}{sub NMAD} = 1.48 Multiplication-Sign MAD = 0.017 for non-outliers. We show that templates that optimally describe the brightest galaxies (-24.5 {<=} M{sub R} {<=} -22.7) indeed vary from z = 0.1 to z = 0.5, consistent with aging of the stellar population. Furthermore, we find that templates that optimally describe galaxies at z < 0.1 strongly differ as a function of the absolute magnitude of the galaxies, indicating an increase in star formation activity for less luminous galaxies. Our findings based on the photometry of the SDSS LRGs and our SED template fitting are supported by comparison to the average SDSS LRG spectra in different luminosity and redshift bins.

  10. Tunable THz Generation by the Interaction of a Super-luminous Laser Pulse with Biased Semiconductor Plasma

    SciTech Connect (OSTI)

    Papadopoulos, K. [BAE Systems-ATI, University of Maryland, College Park MD 20742 (United States); Zigler, A. [BAE Systems-ATI, Hebrew University (Israel)

    2006-01-03T23:59:59.000Z

    Terahertz (THz) radiation is electromagnetic radiation in the range between several hundred and a few thousand GHz. It covers the gap between fast-wave electronics (millimeter waves) and optics (infrared). This spectral region offers enormous potential for detection of explosives and chemical/biological agents, non-destructive testing of non-metallic structural materials and coatings of aircraft structures, medical imaging, bio-sensing of DNA stretching modes and high-altitude secure communications. The development of these applications has been hindered by the lack of powerful, tunable THz sources with controlled waveform. The need for such sources is accentuated by the strong, but selective absorption of THz radiation during transmission through air with high vapor content. The majority of the current experimental work relies on time-domain spectroscopy using fast electrically biased photoconductive sources in conjunction with femto-second mode-locked Ti:Sapphire lasers. These sources known as Large Aperture Photoconductive Antennas (LAPA) have very limited tunability, relatively low upper bound of power and no bandwidth control. The paper presents a novel source of THz radiation known as Miniature Photoconductive Capacitor Array (MPCA). Experiments demonstrated tunability between .1 - 2 THz, control of the relative bandwidth {delta}f/f between .5-.01, and controlled pulse length and pulse waveform (temporal shape, chirp, pulse-to-pulse modulation etc.). Direct scaling from the current device indicates efficiency in excess of 30% at 1 THz with 1/f2 scaling at higher frequencies, peak power of 100 kW and average power between .1-1 W. The physics underlying the MPCA is the interaction of a super-luminous ionization front generated by the oblique incidence of a Ti:Sapphire laser pulse on a semiconductor crystal (ZnSe) biased with an alternating electrostatic field, similar to that of a frozen wave generator. It is shown theoretically and experimentally that the interaction results in the emission of an electromagnetic wave at the plasma frequency of the ionization front. The device resembles the well-known DARC plasma device with two significant differences. First, the frozen wave is on a semiconductor crystal and not on a gas (Azulene Vapor). Second, the ionizing front is super-luminous. These differences result in a device with superior tunability, efficiency, compactness and flexibility. The paper concludes with examples of THz imaging using the MPCA.

  11. Maximum Power Point Tracking Control for Photovoltaic System Using Adaptive Neuro-Fuzzy

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Maximum Power Point Tracking Control for Photovoltaic System Using Adaptive Neuro- Fuzzy "ANFIS energy demand. The mathematical modeling and simulation of the photovoltaic system is implemented) like ANFIS. This paper presents Maximum Power Point Tracking Control for Photovoltaic System Using

  12. A Maximum Entropy Algorithm for Rhythmic Analysis of Genome-Wide Expression Patterns

    E-Print Network [OSTI]

    Richardson, David

    A Maximum Entropy Algorithm for Rhythmic Analysis of Genome-Wide Expression Patterns Christopher James Langmead C. Robertson McClung Bruce Randall Donald ,,,§,¶ Abstract We introduce a maximum entropy-based spectral analysis, maximum entropy spectral reconstruction is well suited to signals of the type generated

  13. 1 A MAXIMUM ENTROPY METHOD FOR SUBNETWORK ORIGIN-DESTINATION 2 TRIP MATRIX ESTIMATION

    E-Print Network [OSTI]

    Kockelman, Kara M.

    1 A MAXIMUM ENTROPY METHOD FOR SUBNETWORK ORIGIN-DESTINATION 2 TRIP MATRIX ESTIMATION 3 4 Chi Xie 5, maximum entropy, linearization 36 algorithm, column generation 37 #12;C. Xie, K.M. Kockelman and S is the trip matrix of the simplified network. This paper discusses a5 maximum entropy method

  14. Maximum entropy and Bayesian approaches to the ratio problem Edward Z. Shen*

    E-Print Network [OSTI]

    Perloff, Jeffrey M.

    Maximum entropy and Bayesian approaches to the ratio problem Edward Z. Shen* Jeffrey M. Perloff** January 2001 Abstract Maximum entropy and Bayesian approaches provide superior estimates of a ratio extra information in the supports for the underlying parameters for generalized maximum entropy (GME

  15. Comparison of Maximum Entropy and Higher-Order Entropy Estimators Amos Golan* and Jeffrey M. Perloff**

    E-Print Network [OSTI]

    Perloff, Jeffrey M.

    Comparison of Maximum Entropy and Higher-Order Entropy Estimators Amos Golan* and Jeffrey M. Perloff** ABSTRACT We show that the generalized maximum entropy (GME) is the only estimation method- classes of estimators may outperform the GME estimation rule. Keywords: generalized entropy, maximum

  16. A maximum entropy-least squares estimator for elastic origin-destination trip matrix estimation

    E-Print Network [OSTI]

    Kockelman, Kara M.

    A maximum entropy-least squares estimator for elastic origin- destination trip matrix estimation propose a combined maximum entropy-least squares (ME-LS) estimator, by which O- D flows are distributed-destination trip table; elastic demand; maximum entropy; least squares; subnetwork analysis; convex combination

  17. The AGN content in luminous IR galaxies at z\\sim2 from a global SED analysis including Herschel data

    E-Print Network [OSTI]

    Pozzi, F; Gruppioni, C; Feltre, A; Fritz, J; Fadda, D; Andreani, P; Berta, S; Cimatti, A; Delvecchio, I; Lutz, D; Magnelli, B; Maiolino, R; Nordon, R; Popesso, P; Rodighiero, G; Rosario, D; Santini, P; Vaccari, M

    2012-01-01T23:59:59.000Z

    We use Herschel-PACS far-infrared data, combined with previous multi-band information and mid-IR spectra, to properly account for the presence of an active nucleus and constrain its energetic contribution in luminous infrared (IR) sources at z\\sim2. The sample is composed of 24 sources in the GOODS-South field, with typical IR luminosity of 10^{12} Lo. Data from the 4 Ms Chandra X-ray imaging in this field are also used to identify and characterize AGN emission. We reproduce the observed spectral energy distribution (SED), decomposed into a host-galaxy and an AGN component. A smooth-torus model for circum-nuclear dust is used to account for the direct and re-processed contribution from the AGN. We confirm that galaxies with typical L_{8-1000um}\\sim10^{12}Lo at z\\sim2 are powered predominantly by star-formation. An AGN component is present in nine objects (\\sim35% of the sample) at the 3sigma confidence level, but its contribution to the 8-1000 um emission accounts for only \\sim5% of the energy budget. The AGN...

  18. Feedback-Driven Evolution of the Far-Infrared Spectral Energy Distributions of Luminous and Ultraluminous Infrared Galaxies

    E-Print Network [OSTI]

    Sukanya Chakrabarti; T. J. Cox; Lars Hernquist; Philip F. Hopkins; Brant Robertson; Tiziana Di Matteo

    2007-01-22T23:59:59.000Z

    We calculate infrared spectral energy distributions (SEDs) from simulations of major galaxy mergers and study the effect of AGN and starburst driven feedback on the evolution of the SED as a function of time. We use a self-consistent three-dimensional radiative equilibrium code to calculate the emergent SEDs and to make images. To facilitate a simple description of our findings, we describe our results in reference to an approximate analytic solution for the far-IR SED. We focus mainly on the luminous infrared galaxy (LIRG) and ultraluminous infrared galaxy (ULIRG) phases of evolution. We contrast the SEDs of simulations performed with AGN feedback to simulations performed with starburst driven wind feedback. We find that the feedback processes critically determine the evolution of the SED. Changing the source of illumination (whether stellar or AGN) has virtually no impact on the reprocessed far-infrared SED. We find that AGN feedback is particularly effective at dispersing gas and rapidly injecting energy into the ISM. The observational signature of such powerful feedback is a warm SED. In general, simulations performed with starburst driven winds have colder spectra and reprocess more of their emission into the infrared, resulting in higher infrared to bolometric luminosities compared to (otherwise equivalent) simulations performed with AGN feedback. We depict our results in IRAS bands, as well as in Spitzer's MIPS bands, and in Herschel's PACS bands.

  19. NEAR-INFRARED ADAPTIVE OPTICS IMAGING OF INFRARED LUMINOUS GALAXIES: THE BRIGHTEST CLUSTER MAGNITUDE-STAR FORMATION RATE RELATION

    SciTech Connect (OSTI)

    Randriamanakoto, Z.; Väisänen, P. [South African Astronomical Observatory, P.O. Box 9, 7935 Observatory, Cape Town (South Africa)] [South African Astronomical Observatory, P.O. Box 9, 7935 Observatory, Cape Town (South Africa); Escala, A. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)] [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Kankare, E.; Kotilainen, J.; Mattila, S. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland)] [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Ryder, S., E-mail: zara@saao.ac.za [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia)

    2013-10-01T23:59:59.000Z

    We have established a relation between the brightest super star cluster (SSC) magnitude in a galaxy and the host star formation rate (SFR) for the first time in the near-infrared (NIR). The data come from a statistical sample of ?40 luminous IR galaxies (LIRGs) and starbursts utilizing K-band adaptive optics imaging. While expanding the observed relation to longer wavelengths, less affected by extinction effects, it also pushes to higher SFRs. The relation we find, M{sub K} ? –2.6log SFR, is similar to that derived previously in the optical and at lower SFRs. It does not, however, fit the optical relation with a single optical to NIR color conversion, suggesting systematic extinction and/or age effects. While the relation is broadly consistent with a size-of-sample explanation, we argue physical reasons for the relation are likely as well. In particular, the scatter in the relation is smaller than expected from pure random sampling strongly suggesting physical constraints. We also derive a quantifiable relation tying together cluster-internal effects and host SFR properties to possibly explain the observed brightest SSC magnitude versus SFR dependency.

  20. Common Patterns in the Evolution between the Luminous Neutron Star Low-Mass X-ray Binary Subclasses

    E-Print Network [OSTI]

    Fridriksson, Joel K; Remillard, Ronald A

    2015-01-01T23:59:59.000Z

    The X-ray transient XTE J1701-462 was the first source seen to evolve through all known subclasses of low-magnetic-field neutron star low-mass X-ray binaries (NS-LMXBs), as a result of large changes in its mass accretion rate. To investigate to what extent similar evolution is seen in other NS-LMXBs we have performed a detailed study of the color-color and hardness-intensity diagrams (CDs and HIDs) of Cyg X-2, Cir X-1, and GX 13+1 -- three luminous X-ray binaries, containing weakly magnetized neutron stars, known to exhibit strong secular changes in their CD/HID tracks. Using the full set of Rossi X-ray Timing Explorer Proportional Counter Array data collected for the sources over the 16-year duration of the mission, we show that Cyg X-2 and Cir X-1 display CD/HID evolution with close similarities to XTE J1701-462. Although GX 13+1 shows behavior that is in some ways unique, it also exhibits similarities to XTE J1701-462, and we conclude that its overall CD/HID properties strongly indicate that it should be c...

  1. A propeller model for the sub-luminous disk state of the transitional millisecond pulsar PSR J1023+0038

    E-Print Network [OSTI]

    Papitto, A

    2015-01-01T23:59:59.000Z

    The discovery of millisecond pulsars switching between states powered either by the rotation of their magnetic field or by the accretion of matter, has recently proved the tight link shared by millisecond radio pulsars and neutron stars in low-mass X-ray binaries. Transitional millisecond pulsars also show an enigmatic intermediate state in which the neutron star is surrounded by an accretion disk, it emits coherent X-ray pulsations, but is sub-luminous in X-rays with respect to accreting neutron stars, and is brighter in gamma-rays than millisecond pulsars in the rotation-powered state. Here, we model the X-ray and gamma-ray emission observed from PSR J1023+0038 in such a state based on the assumption that most of the disk in-flow is propelled away by the rapidly rotating neutron star magnetosphere, and that electrons can be accelerated to energies of a few GeV at the turbulent disk-magnetosphere boundary. We show that the synchrotron and self-synchrotron Compton emission coming from such a region, together ...

  2. XMM-Newton observations of 4 luminous radio-quiet AGN, and the soft X-ray excess problem

    E-Print Network [OSTI]

    F. D'Ammando; S. Bianchi; E. Jimenez-Bailon; G. Matt

    2008-01-30T23:59:59.000Z

    The nature and origin of the soft X-ray excess in radio quiet AGN is still an open issue. The interpretation in terms of thermal disc emission has been challanged by the discovery of the constancy of the effective temperature despite the wide range of Black Hole masses of the observed sources. Alternative models are reflection from ionized matter and absorption in a relativistically smeared wind. We analyzed XMM-Newton observations of four luminous radio quiet AGN with the aim of characterising their main properties and in particular the soft excess. Different spectral models for the soft excess were tried: thermal disc emission, Comptonization, ionized reflection, relativistically smeared winds. Comptonization of thermal emission and the smeared winds provide the best fits, but the other models also provide acceptable fits. All models, however, return parameters very similar from source to source, despite the large differences in luminosities, Black Hole masses and Eddington ratios. Moreover, the smeared wind model require very large smearing velocities. The UV to X-ray fluxes ratios are very different, but do not correlate with any other parameter. No fully satisfactory explanation for the soft X-ray excess is found. Better data, like e.g. observations in a broader energy band, are needed to make further progresses.

  3. Phosphors for near UV-Emitting LED's for Efficacious Generation of White Light

    SciTech Connect (OSTI)

    McKittrick, Joanna

    2013-09-30T23:59:59.000Z

    1) We studied phosphors for near-UV (nUV) LED application as an alternative to blue LEDs currently being used in SSL systems. We have shown that nUV light sources could be very efficient at high current and will have significantly less binning at both the chip and phosphor levels. We identified phosphor blends that could yield 4100K lamps with a CRI of approximately 80 and LPWnUV,opt equal to 179 for the best performing phosphor blend. Considering the fact that the lamps were not optimized for light coupling, the results are quite impressive. The main bottleneck is an optimum blue phosphor with a peak near 440 nm with a full width half maximum of about 25 nm and a quantum efficiency of >95%. Unfortunately, that may be a very difficult task when we want to excite a phosphor at ~400 nm with a very small margin for Stokes shift. Another way is to have all the phosphors in the blend having the excitation peak at 400 nm or slightly shorter wavelength. This could lead to a white light source with no body color and optimum efficacy due to no self-absorption effects by phosphors in the blend. This is even harder than finding an ideal blue phosphor, but not necessarily impossible. 2) With the phosphor blends identified, light sources using nUV LEDs at high current could be designed with comparable efficacy to those using blue LEDs. It will allow us to design light sources with multiple wattages using the same chips and phosphor blends simply by varying the input current. In the case of blue LEDs, this is not currently possible because varying the current will lower the efficacy at high current and alter the color point. With improvement of phosphor blends, control over CRI could improve. Less binning at the chip level and also at the phosphor blend level could reduce the cost of SSL light sources. 3) This study provided a deeper understanding of phosphor characteristics needed for LEDs in general and nUV LEDs in particular. Two students received Ph.D. degrees and three undergraduates participated in this work. Two of the undergraduate students are now in graduate school. The results were widely disseminated – 20 archival journal publications (published, accepted or in preparation) and three conference proceedings resulted. The students presented their work at 11 different national/international conferences (32 oral or poster presentations) and the PI’s delivered 12 invited, keynote or plenary lectures.

  4. Inconsistence of super-luminal Cern-Opera neutrino speed with observed SN1987A burst and neutrino mixing for any imaginary neutrino mass

    E-Print Network [OSTI]

    D. Fargion; D. D'Armiento

    2012-03-05T23:59:59.000Z

    We tried to fit in any way the recent Opera-Cern claims of a neutrino super-luminal speed with observed Supernova SN1987A neutrino burst and all (or most) neutrino flavor oscillation. We considered three main frame-works: (1) A tachyon imaginary neutrino mass, whose timing is nevertheless in conflict with observed IMB-Kamiokande SN1987A burst by thousands of billion times longer. (2) An ad hoc anti-tachyon model whose timing shrinkage may accommodate SN1987A burst but greatly disagree with energy independent Cern-Opera super-luminal speed. (3) A split neutrino flavor speed (among a common real mass relativistic neutrino electron component and a super-luminal neutrino {\\mu}) in an ad hoc frozen speed scenario that is leading to the prompt neutrino de-coherence and the rapid flavor mixing (between electron and muon ones) that are in conflict with most oscillation records. Therefore we concluded that an error must be hidden in Opera-Cern time calibration (as indeed recent rumors seem to confirm). We are also reminding the relevance of the guaranteed minimal atmospheric neutrino mass whose detection may be achieved by a milliseconds graviton-neutrino split time delay among gravity burst and neutronization neutrino peak in any future SN explosion in Andromeda recordable in Megaton neutrino detector.

  5. Two temperature accretion around rotating black holes: Description of general advective flow paradigm in presence of various cooling processes to explain low to high luminous sources

    E-Print Network [OSTI]

    S. R. Rajesh; Banibrata Mukhopadhyay

    2009-10-23T23:59:59.000Z

    We investigate the viscous two temperature accretion discs around rotating black holes. We describe the global solution of accretion flows with a sub-Keplerian angular momentum profile, by solving the underlying conservation equations including explicit cooling processes selfconsistently. Bremsstrahlung, synchrotron and inverse Comptonization of soft photons are considered as possible cooling mechanisms, for sub-Eddington, Eddington and super-Eddington mass accretion rates around Schwarzschild and Kerr black holes with a Kerr parameter 0.998. It is found that the flow, during its infall from the Keplerian to sub-Keplerian transition region to the black hole event horizon, passes through various phases of advection -- general advective paradigm to radiatively inefficient phase and vice versa. Hence the flow governs much lower electron temperature ~10^8-10^{9.5} K, in the range of accretion rate in Eddington units 0.01 luminous X-ray sources (e.g. SS433), at different combinations of input parameters such as mass accretion rate, ratio of specific heats. The set of solutions also predicts appropriately the luminosity observed in the highly luminous AGNs and ultra-luminous quasars (e.g. PKS 0743-67).

  6. Evidence for PopIII-like stellar populations in the most luminous Lyman-$\\alpha$ emitters at the epoch of re-ionisation: spectroscopic confirmation

    E-Print Network [OSTI]

    Sobral, David; Darvish, Behnam; Schaerer, Daniel; Mobasher, Bahram; Röttgering, Huub; Santos, Sérgio; Hemmati, Shoubaneh

    2015-01-01T23:59:59.000Z

    Faint Lyman-$\\alpha$ (Ly$\\alpha$) emitters become increasingly rarer towards the re-ionisation epoch (z~6-7). However, observations from a very large (~5deg$^2$) Ly$\\alpha$ survey at z=6.6 (Matthee et al. 2015) show that this is not the case for the most luminous emitters. Here we present follow-up observations of the two most luminous z~6.6 Ly$\\alpha$ candidates in the COSMOS field: `MASOSA' and `CR7'. We used X-SHOOTER, SINFONI and FORS2 (VLT), and DEIMOS (Keck), to confirm both candidates beyond any doubt. We find redshifts of z=6.541 and z=6.604 for MASOSA and CR7, respectively. MASOSA has a strong detection in Ly$\\alpha$ with a line width of $386\\pm30$ km/s (FWHM) and with high EW$_0$ (>200 \\AA), but it is undetected in the continuum. CR7, with an observed Ly$\\alpha$ luminosity of $10^{43.93\\pm0.05}$erg/s is the most luminous Ly$\\alpha$ emitter ever found at z>6. CR7 reveals a narrow Ly$\\alpha$ line with $266\\pm15$ km/s FWHM, being detected in the NIR (rest-frame UV, with $\\beta=-2.3\\pm0.1$) with an exce...

  7. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    SciTech Connect (OSTI)

    Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

    2000-02-26T23:59:59.000Z

    Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

  8. The therapeutic efficacy of camptothecin-encapsulated supramolecular nanoparticles

    E-Print Network [OSTI]

    Cheng, Jianjun

    The therapeutic efficacy of camptothecin-encapsulated supramolecular nanoparticles Kuan-Ju Chen a,1 of Materials Science and Engineering, University of Illinois at Urbana-Champaign-Urbana, 1304 West Green Street October 2011 Available online 8 November 2011 Keywords: Supramolecular assembly Nanoparticles Drug

  9. Formalizing Concepts for Efficacy-aware Business Process Modeling

    E-Print Network [OSTI]

    Ulm, Universität

    Formalizing Concepts for Efficacy-aware Business Process Modeling Matthias Lohrmann and Manfred.lohrmann,manfred.reichert}@uni-ulm.de Abstract. In business process design, business objective models can ful- fill the role of formal business process management concepts yet. Moreover, process models are currently not sufficiently

  10. Phytotoxicity and Efficacy of Sumagic (Uniconazole) for Growth Control of

    E-Print Network [OSTI]

    Lieth, J. Heinrich

    Phytotoxicity and Efficacy of Sumagic (Uniconazole) for Growth Control of Mexican Sage (Salvia Bush Sage Salvia leucantha cv. `Santa Barbara' REASON: Height Control SOIL TYPE OR TYPE OF POTTING MIX: UC Mix % SAND 30 % SILT % CLAY % OM 70 pH 6.5 SEEDING DATE EMERGENCE DATE TRANSPLANTING DATE: 3

  11. Efficacy and Phytotoxicity of Sumagic (Uniconazole) for Growth Control of

    E-Print Network [OSTI]

    Lieth, J. Heinrich

    Efficacy and Phytotoxicity of Sumagic (Uniconazole) for Growth Control of Egyptian Star Star-Cluster Pentas lanceolata cv. `Butterfly Pink' REASON: Control of vegetative growth SOIL TYPE OR TYPE OF POTTING MIX: UC Mix % SAND 30 % SILT % CLAY % OM 70 pH 6.5 SEEDING DATE EMERGENCE DATE

  12. Cree Sets New Benchmarks for LED Efficacy and Brightness

    Broader source: Energy.gov [DOE]

    Cree has successfully created a cool white LED prototype that delivers 107 lm/W at 350mA. This achievement builds on the Cree EZBright® LED chip platform, developed in part with prior funding support from DOE. Cree made the prototype LED under their DOE project focused on developing LED chips incorporating photonic crystal elements for improved light extraction and novel package technology for higher down-conversion efficiency compared to conventional LEDs. Based on a 1 millimeter-square chip, the new prototype LED produces white light with a CCT of 5500K and a CRI of 73. Integration of four of these prototype LEDs can produce luminous flux of more than 450 lumens.

  13. Infrared 3-4 Micron Spectroscopy of Infrared Luminous Galaxies with Possible Signatures of Obscured Active Galactic Nuclei

    E-Print Network [OSTI]

    Masatoshi Imanishi

    2006-02-10T23:59:59.000Z

    We present the results of infrared 2.8-4.1 micron (L-band) spectroscopy of nearby infrared luminous galaxies with possible signatures of dust-obscured active galactic nuclei (AGNs) in data at other wavelengths. The samples are chosen to include sources with a radio excess relative to far-infrared emission, strong absorption features in mid-infrared 5-11.5 micron spectra, unusually weak [CII] 158 micron emission relative to the far-infrared continuum, and radio galaxies classified optically as narrow-line objects. Our aim is to investigate whether the signatures of possible obscured AGNs can be detected in our L-band spectra, based on the strengths of emission and absorption features. Six of nine observed sources clearly show 3.3 micron polycyclic aromatic hydrocarbon (PAH) emission features, a good starburst indicator. An absorption feature at 3.1 micron due to ice-covered dust is detected in IRAS 04154+1755 and IRAS 17208-0014. The signature of a bare carbonaceous dust absorption feature at 3.4 micron is seen in NGC 1377. Our L-band spectra reveal strong signatures of obscured AGNs in all three optical Seyfert 2 galaxies (IRAS 04154+1755, Cygnus A, and 3C 234), and two galaxies classified optically as non-Seyferts (NGC 828 and NGC 1377). Among the remaining optical non-Seyferts, IRAS 17208-0014 might also show a buried AGN signature, whereas no explicit AGN evidence is seen in the L-band spectra of the mid-infrared absorption-feature source IRAS 15250+3609, and two weak [CII] emitters IC 860 and CGCG 1510.8+0725.

  14. A multi-wavelength view of the central kiloparsec region in the luminous infrared galaxy NGC 1614

    SciTech Connect (OSTI)

    Herrero-Illana, Rubén; Pérez-Torres, Miguel Á.; Alberdi, Antxon; Hernández-García, Lorena [Instituto de Astrofísica de Andalucía-CSIC, P.O. Box 3004, E-18008 Granada (Spain); Alonso-Herrero, Almudena [Instituto de Física de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander (Spain); Colina, Luis [Centro de Astrobiología (INTA-CSIC), Ctra. de Torrejón a Ajalvir, km 4, E-28850 Torrejón de Ardoz, Madrid (Spain); Efstathiou, Andreas [School of Sciencies, European University Cyprus, Diogenes Street, Engomi, 1516 Nicosia (Cyprus); Miralles-Caballero, Daniel [Instituto de Física Teórica, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Väisänen, Petri [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 Cape Town (South Africa); Packham, Christopher C. [Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 (United States); Rajpaul, Vinesh [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Zijlstra, Albert A. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-05-10T23:59:59.000Z

    The Luminous Infrared Galaxy NGC 1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ?100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Pa?, optical, and X-ray observations of NGC 1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array and the Gemini/T-ReCS 8.7 ?m emission, as well as the Pa? line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used a Hubble Space Telescope/NICMOS Pa? map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power law for each individual region within the central kiloparsec of NGC 1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an active galactic nucleus (AGN), but rather by a compact (r ? 90 pc) starburst (SB). Chandra X-ray data also show that the central kiloparsec region is dominated by SB activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the SB ring and a putative AGN in NGC 1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.

  15. Measured Off-Grid LED Lighting System Performance

    E-Print Network [OSTI]

    Granderson, Jessica

    2009-01-01T23:59:59.000Z

    beam candlepower, and luminance varied by 8x, 32x, and 61xMaximum beam candlepower Luminance (cd/m2) Daylight glarequality, luminous intensity, luminance, and glare. Note that

  16. SSL Pricing and Efficacy Trend Analysis for Utility Program Planning

    SciTech Connect (OSTI)

    Tuenge, Jason R.

    2013-10-01T23:59:59.000Z

    An LED lamp or luminaire can generally be found that matches or exceeds the efficacy of benchmark technologies in a given product category, and LED products continue to expand into ever-higher lumen output niches. However, the price premium for LED continues to pose a barrier to adoption in many applications, in spite of expected savings from reduced energy use and maintenance. Other factors—such as dimmability and quality of light—can also present challenges. The appropriate type, timing, and magnitude of energy efficiency activities will vary from organization to organization based on local variables and the method of evaluation. A number of factors merit consideration when prioritizing activities for development. Category-specific projections for pricing and efficacy are provided herein to assist in efficiency program planning efforts.

  17. Luminous Dark Matter

    E-Print Network [OSTI]

    Brian Feldstein; Peter W. Graham; Surjeet Rajendran

    2011-01-13T23:59:59.000Z

    We propose a dark matter model in which the signal in direct detection experiments arises from electromagnetic, not nuclear, energy deposition. This can provide a novel explanation for DAMA while avoiding many direct detection constraints. The dark matter state is taken nearly degenerate with another state. These states are naturally connected by a dipole moment operator, which can give both the dominant scattering and decay modes between the two states. The signal at DAMA then arises from dark matter scattering in the Earth into the excited state and decaying back to the ground state through emission of a single photon in the detector. This model has unique signatures in direct detection experiments. The density and chemical composition of the detector is irrelevant, only the total volume affects the event rate. In addition, the spectrum is a monoenergetic line, which can fit the DAMA signal well. This model is readily testable at experiments such as CDMS and XENON100 if they analyze their low-energy, electronic recoil events.

  18. THE BARYONIC ACOUSTIC FEATURE AND LARGE-SCALE CLUSTERING IN THE SLOAN DIGITAL SKY SURVEY LUMINOUS RED GALAXY SAMPLE

    SciTech Connect (OSTI)

    Kazin, Eyal A.; Blanton, Michael R.; Scoccimarro, Roman [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); McBride, Cameron K.; Berlind, Andreas A. [Department of Physics and Astronomy, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States); Bahcall, Neta A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Brinkmann, Jon [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Czarapata, Paul [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Frieman, Joshua A. [Particle Astrophysics Center, Fermilab, P.O. Box 500, Batavia, IL 60510 (United States); Kent, Stephen M. [MS 127, Fermilab, P.O. Box 500, Batavia, IL 60510 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Szalay, Alexander S., E-mail: eyalkazin@gmail.co [Department of Physics and Astronomy, The Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218 (United States)

    2010-02-20T23:59:59.000Z

    We examine the correlation function xi of the Sloan Digital Sky Survey Luminous Red Galaxy sample at large scales (60 h {sup -1} Mpc < s < 400 h {sup -1} Mpc) using the final data release (DR7). Focusing on a quasi-volume-limited (0.16 < z < 0.36) subsample and utilizing mock galaxy catalogs, we demonstrate that the observed baryonic acoustic peak and larger scale signal are consistent with LAMBDACDM at 70%-95% confidence. Fitting data to a non-linear, redshift-space, template-based model, we constrain the peak position at s{sub p} = 101.7+- 3.0 h {sup -1} Mpc when fitting the range 60 h {sup -1} Mpc < s < 150 h {sup -1} Mpc (1sigma uncertainties). This redshift-space distance s{sub p} is related to the comoving sound horizon scale r{sub s} after taking into account matter-clustering non-linearities, redshift distortions, and galaxy-clustering bias. Mock catalogs show that the probability that a DR7-sized sample would not have an identifiable peak is at least {approx}10%. As a consistency check of a fiducial cosmology, we use the observed s{sub p} to obtain the distance D{sub V}{identical_to}((1+z){sup 2}D{sup 2}{sub A}cz/H(z)){sup 1/3} relative to the acoustic scale. We find r{sub s} /D{sub V} (z = 0.278) = 0.1389 +- 0.0043. This result is in excellent agreement with Percival et al., who examine roughly the same data set, but use the power spectrum. Comparison with other determinations in the literature are also in very good agreement. The signal of the full sample at 125 h {sup -1} Mpc < s < 200 h {sup -1} Mpc tends to be high relative to theoretical expectations; this slight deviation can probably be attributed to sample variance. We have tested our results against a battery of possible systematic effects, finding all effects are smaller than our estimated sample variance.

  19. The number e^{(1/2)} is the ratio between the time of maximum value and the time of maximum growth rate for restricted growth phenomena?

    E-Print Network [OSTI]

    Zi-Niu Wu

    2013-10-02T23:59:59.000Z

    For many natural process of growth, with the growth rate independent of size due to Gibrat law and with the growth process following a log-normal distribution, the ratio between the time (D) for maximum value and the time (L) for maximum growth rate (inflexion point) is then equal to the square root of the base of the natural logarithm (e^{1/2}). On the logarithm scale this ratio becomes one half ((1/2)). It remains an open question, due to lack of complete data for various cases with restricted growth, whether this e^{1/2} ratio can be stated as e^{1/2}-Law. Two established examples already published, one for an epidemic spreading and one for droplet production, support however this ratio. Another example appears to be the height of humain body. For boys the maximum height occurs near 23 years old while the maximum growth rate is at the age near 14, and there ratio is close to e^{1/2}. The main theoretical base to obtain this conclusion is problem independent, provided the growth process is restricted, such as public intervention to control the spreading of communicable epidemics, so that an entropy is associated with the process and the role of dissipation, representing the mechanism of intervention, is maximized. Under this formulation the principle of maximum rate of entropy production is used to make the production process problem independent.

  20. Use of Two Distillation Columns in Systems with Maximum Temperature Limitations

    E-Print Network [OSTI]

    Gilchrist, James F.

    Use of Two Distillation Columns in Systems with Maximum Temperature Limitations Rebecca H. Masel, Pennsylvania 18015, United States ABSTRACT: Maximum temperature limitations are encountered in distillation of the bottoms product fixes the column base pressure and, hence, the condenser pressure. The distillate

  1. Maximum Power Transfer Tracking in a Solar USB Charger for Smartphones

    E-Print Network [OSTI]

    Pedram, Massoud

    chargers do not perform the maximum power point tracking [2], [3] of the solar panel. We excludeMaximum Power Transfer Tracking in a Solar USB Charger for Smartphones Abstract--Battery life poor capacity utilization during solar energy harvesting. In this paper, we propose and demonstrate

  2. LANGMUIR WAVE ACTIVITY: COMPARING THE ULYSSES SOLAR MINIMUM AND SOLAR MAXIMUM ORBITS

    E-Print Network [OSTI]

    California at Berkeley, University of

    ). The top three panels correspond to the southern segment of the solar minimum orbit; repeated passesLANGMUIR WAVE ACTIVITY: COMPARING THE ULYSSES SOLAR MINIMUM AND SOLAR MAXIMUM ORBITS R. J at the electron plasma frequency) during the solar minimum and solar maximum orbits of Ulysses. At high latitudes

  3. Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated Tropical Cyclone*

    E-Print Network [OSTI]

    Wang, Yuqing

    Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated is eventually dissipated due to surface friction. Since the energy production rate is a linear function while frictional dissipation rate balances the energy production rate near the radius of maximum wind (RMW

  4. Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated Tropical Cyclone

    E-Print Network [OSTI]

    Wang, Yuqing

    0 Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated is eventually dissipated due to surface friction. Since the energy production rate is a linear function while frictional dissipation rate balances the energy production rate near the radius of maximum wind (RMW

  5. Efficiency at maximum power of low dissipation Carnot engines Massimiliano Esposito

    E-Print Network [OSTI]

    Kawai, Ryoichi

    Efficiency at maximum power of low dissipation Carnot engines Massimiliano Esposito Center the efficiency at maximum power, , of engines performing finite-time Carnot cycles between a hot and a cold reservoir at temperatures Th and Tc, respectively. For engines reaching Carnot efficiency C = 1 - Tc

  6. Maximum Theoretical Efficiency Limit of Photovoltaic Devices: Effect of Band Structure on Excited State Entropy

    E-Print Network [OSTI]

    Osterloh, Frank

    Maximum Theoretical Efficiency Limit of Photovoltaic Devices: Effect of Band Structure on Excited a theoretical limit for the maximum energy conversion efficiency of single junction photovoltaic cells for the efficiency variations observed for real photovoltaic devices today.4-6 Here, we show that the extractable

  7. Maximum-Power-Point Tracking Method of Photovoltaic Using Only Single Current Sensor

    E-Print Network [OSTI]

    Fujimoto, Hiroshi

    » «Solar cell systems» Abstract This paper describes a novel strategy of maximum-power-point tracking point using only a single current sensor, i.e., a Hall-effect CT. Output power of the photovoltaic can-climbing method is employed to seek the maximum power point, using the output power obtained from only the current

  8. An Improved Maximum Likelihood Formulation for Accurate Genome Assembly Aditya Varma, Abhiram Ranade and Srinivas Aluru

    E-Print Network [OSTI]

    Ranade, Abhiram G.

    An Improved Maximum Likelihood Formulation for Accurate Genome Assembly Aditya Varma, Abhiram maximum likelihood method for genome assembly. We formulate the problem as one of direct convex estimate of the length of the genome or the need to use further expectation minimization to predict

  9. How Is the Maximum Entropy of a Quantized Surface Related to Its Area?

    E-Print Network [OSTI]

    I. B. Khriplovich; R. V. Korkin

    2001-12-27T23:59:59.000Z

    The maximum entropy of a quantized surface is demonstrated to be proportional to the surface area in the classical limit. The result is valid in loop quantum gravity, and in a somewhat more general class of approaches to surface quantization. The maximum entropy is calculated explicitly for some specific cases.

  10. Analyticity, Convergence and Convergence Rate of Recursive Maximum Likelihood Estimation in Hidden Markov Models

    E-Print Network [OSTI]

    Tadi?, Vladislav B

    2009-01-01T23:59:59.000Z

    This paper considers the asymptotic properties of the recursive maximum likelihood estimation in hidden Markov models. The paper is focused on the asymptotic behavior of the log-likelihood function and on the point-convergence and convergence rate of the recursive maximum likelihood estimator. Using the principle of analytical continuation, the analyticity of the asymptotic log-likelihood function is shown for analytically parameterized hidden Markov models. Relying on this fact and some results from differential geometry (Lojasiewicz inequality), the almost sure point-convergence of the recursive maximum likelihood algorithm is demonstrated, and relatively tight bounds on the convergence rate are derived. As opposed to the existing result on the asymptotic behavior of maximum likelihood estimation in hidden Markov models, the results of this paper are obtained without assuming that the log-likelihood function has an isolated maximum at which the Hessian is strictly negative definite.

  11. Unification of Field Theory and Maximum Entropy Methods for Learning Probability Densities

    E-Print Network [OSTI]

    Kinney, Justin B

    2014-01-01T23:59:59.000Z

    Bayesian field theory and maximum entropy are two methods for learning smooth probability distributions (a.k.a. probability densities) from finite sampled data. Both methods were inspired by statistical physics, but the relationship between them has remained unclear. Here I show that Bayesian field theory subsumes maximum entropy density estimation. In particular, the most common maximum entropy methods are shown to be limiting cases of Bayesian inference using field theory priors that impose no boundary conditions on candidate densities. This unification provides a natural way to test the validity of the maximum entropy assumption on one's data. It also provides a better-fitting nonparametric density estimate when the maximum entropy assumption is rejected.

  12. Neutral carbon and CO in 76 (U)LIRGs and starburst galaxy centers A method to determine molecular gas properties in luminous galaxies

    E-Print Network [OSTI]

    Israel, F P; van der Werf, P

    2015-01-01T23:59:59.000Z

    We present fluxes in both neutral carbon [CI] lines at the centers of 76 galaxies with FIR luminosities between 10^{9} and 10^{12} L(o) obtained with Herschel-SPIRE and with ground-based facilities, along with the J=7-6, J=4-3, J=2-1 12CO and J=2-1 13CO line fluxes. We investigate whether these lines can be used to characterize the molecular ISM of the parent galaxies in simple ways and how the molecular gas properties define the model results. In most starburst galaxies, the [CI]/13CO flux ratio is much higher than in Galactic star-forming regions, and it is correlated to the total FIR luminosity. The [CI](1-0)/CO(4-3), the [CI](2-1) (2-1)/CO(7-6), and the [CI] (2-1)/(1-0) flux ratios are also correlated, and trace the excitation of the molecular gas. In the most luminous infrared galaxies (LIRGs), the ISM is fully dominated by dense and moderately warm gas clouds that appear to have low [C]/[CO] and [13CO]/[12CO] abundances. In less luminous galaxies, emission from gas clouds at lower densities becomes prog...

  13. A Unified Energy-Reservoir Model Containing Contributions from $^{56}$Ni and Neutron Stars and Its Implication to Luminous Type Ic Supernovae

    E-Print Network [OSTI]

    Wang, S Q; Dai, Z G; Wu, X F

    2015-01-01T23:59:59.000Z

    Most type-Ic core-collapse supernovae (CCSNe) produce $^{56}$Ni and neutron stars (NSs) or black holes (BHs). The dipole radiation of nascent NSs has usually been neglected in explaining supernovae (SNe) with peak absolute magnitude $M_{\\rm peak}$ in any band are $\\gtrsim -19.5$~mag, while the $^{56}$Ni can be neglected in fitting most type-Ic superluminous supernovae (SLSNe Ic) whose $M_{\\rm peak}$ in any band are $\\lesssim -21$~mag, since the luminosity from a magnetar (highly magnetized NS) can outshine that from a moderate amount of $^{56}$Ni. For luminous SNe Ic with $-21 \\lesssim M_{\\rm peak}\\lesssim -19.5$~mag, however, both contributions from $^{56}$Ni and NSs cannot be neglected without serious modeling, since they are not SLSNe and the $^{56}$Ni mass could be up to $\\sim 0.5 M_{\\odot}$. In this paper we propose a unified model that contain contributions from both $^{56}$Ni and a nascent NS. We select three luminous SNe Ic-BL, SN~2010ay, SN~2006nx, and SN~14475, and show that, if these SNe are powere...

  14. Efficacy of Lower-Body Shielding in Computed Tomography Fluoroscopy-Guided Interventions

    SciTech Connect (OSTI)

    Mahnken, Andreas H., E-mail: mahnken@rad.rwth-aachen.de [RWTH Aachen, Department of Diagnostic and Interventional Radiology (Germany); Sedlmair, Martin [Siemens, Healthcare Sector (Germany); Ritter, Christine [University of Copenhagen, Niels Bohr Institute (Denmark); Banckwitz, Rosemarie; Flohr, Thomas [Siemens, Healthcare Sector (Germany)

    2012-12-15T23:59:59.000Z

    Purpose: Computed tomography (CT) fluoroscopy-guided interventions pose relevant radiation exposure to the interventionalist. The goal of this study was to analyze the efficacy of lower-body shielding as a simple structural method for decreasing radiation dose to the interventionalist without limiting access to the patient. Material and Methods: All examinations were performed with a 128-slice dual source CT scanner (12 Multiplication-Sign 1.2-mm collimation; 120 kV; and 20, 40, 60, and 80 mAs) and an Alderson-Rando phantom. Scatter radiation was measured with an ionization chamber and a digital dosimeter at standardized positions and heights with and without a lower-body lead shield (0.5-mm lead equivalent; Kenex, Harlow, UK). Dose decreases were computed for the different points of measurement. Results: On average, lower-body shielding decreased scatter radiation by 38.2% within a 150-cm radius around the shielding. This decrease is most significant close to the gantry opening and at low heights of 50 and 100 cm above the floor with a maximum decrease of scatter radiation of 95.9% close to the scanner's isocentre. With increasing distance to the gantry opening, the effect decreased. There is almost no dose decrease effect at {>=}150 above the floor. Scatter radiation and its decrease were linearly correlated with the tube current-time product (r{sup 2} = 0.99), whereas percent scatter radiation decrease was independent of the tube current-time product. Conclusion: Lower-body shielding is an effective way to decrease radiation exposure to the interventionalist and should routinely be used in CT fluoroscopy-guided interventions.

  15. Atlantic Ocean circulation at the last glacial maximum : inferences from data and models

    E-Print Network [OSTI]

    Dail, Holly Janine

    2012-01-01T23:59:59.000Z

    This thesis focuses on ocean circulation and atmospheric forcing in the Atlantic Ocean at the Last Glacial Maximum (LGM, 18-21 thousand years before present). Relative to the pre-industrial climate, LGM atmospheric CO? ...

  16. Tropical climate variability from the last glacial maximum to the present

    E-Print Network [OSTI]

    Dahl, Kristina Ariel

    2005-01-01T23:59:59.000Z

    This thesis evaluates the nature and magnitude of tropical climate variability from the Last Glacial Maximum to the present. The temporal variability of two specific tropical climate phenomena is examined. The first is the ...

  17. Investigating the angle or response and maximum stability of a cohesive granular pile

    E-Print Network [OSTI]

    Nowak, Sara Alice, 1982-

    2004-01-01T23:59:59.000Z

    In this thesis, I investigate the static and dynamic properties of a granular heap made cohesive by an interstitial fluid. I present the results of experimental work measuring the maximum angle of stability and the angle ...

  18. Dynamical Reconstruction of Upper-Ocean Conditions in the Last Glacial Maximum Atlantic

    E-Print Network [OSTI]

    Wunsch, Carl

    Proxies indicate that the Last Glacial Maximum (LGM) Atlantic Ocean was marked by increased meridional and zonal near sea surface temperature gradients relative to today. Using a least squares fit of a full general circulation ...

  19. Achieving Consistent Maximum Brake Torque with Varied Injection Timing in a DI Diesel Engine 

    E-Print Network [OSTI]

    Kroeger, Timothy H

    2013-09-19T23:59:59.000Z

    , revealing the premixed and diffusion burn fractions as well as important engine and exhaust design criteria such as maximum in-cylinder pressure and exhaust composition. These results are significant in diesel engine design because cheaper, lighter engines...

  20. Microcontroller Servomotor for Maximum Effective Power Point for Solar Cell System 

    E-Print Network [OSTI]

    Al-Khalidy, M.; Al-Rawi, O.; Noaman, N.

    2010-01-01T23:59:59.000Z

    In this paper a Maximum Power point (MPP) tracking algorithm is developed using dual-axis servomotor feedback tracking control system. An efficient and accurate servomotor system is used to increase the system efficiency ...

  1. Submodule Integrated Distributed Maximum Power Point Tracking for Solar Photovoltaic Applications

    E-Print Network [OSTI]

    Pilawa-Podgurski, Robert C. N.

    This paper explores the benefits of distributed power electronics in solar photovoltaic applications through the use of submodule integrated maximum power point trackers (MPPT). We propose a system architecture that provides ...

  2. Author's personal copy Unified behaviour of maximum soot yields of methane, ethane and propane

    E-Print Network [OSTI]

    Gülder, Ömer L.

    Author's personal copy Unified behaviour of maximum soot yields of methane, ethane and propane the current study and the previous measurements in similar flames with methane, ethane, and propane flames

  3. Microcontroller Servomotor for Maximum Effective Power Point for Solar Cell System

    E-Print Network [OSTI]

    Al-Khalidy, M.; Al-Rawi, O.; Noaman, N.

    2010-01-01T23:59:59.000Z

    In this paper a Maximum Power point (MPP) tracking algorithm is developed using dual-axis servomotor feedback tracking control system. An efficient and accurate servomotor system is used to increase the system efficiency and reduces the solar cell...

  4. Maximum Network Lifetime in Wireless Sensor Networks with Adjustable Sensing Ranges

    E-Print Network [OSTI]

    Wu, Jie

    1 Maximum Network Lifetime in Wireless Sensor Networks with Adjustable Sensing Ranges Mihaela problem in wireless sensor networks with adjustable sensing range. Communication and sensing consume Wireless sensor networks (WSNs) constitute the foundation of a broad range of applications related

  5. Parameterization of Maximum Wave Heights Forced by Hurricanes: Application to Corpus Christi, Texas

    E-Print Network [OSTI]

    Taylor, Sym 1978-

    2012-12-07T23:59:59.000Z

    sensitivity based on the investigation of several hurricane parameters. Also presented is the development of parameterized maximum significant wave height models. These are determined by incorporating three forms of an equivalent fetch into (1) dimensionless...

  6. A more efficient formulation for computation of the maximum loading points in electric power systems

    SciTech Connect (OSTI)

    Chiang, H.D. [Cornell Univ., Ithaca, NY (United States). School of Electrical Engineering; Jean-Jumeau, R. [Electricite d`Haita, Port-au-Prince (Haiti)

    1995-05-01T23:59:59.000Z

    This paper presents a more efficient formulation for computation of the maximum loading points. A distinguishing feature of the new formulation is that it is of dimension (n + 1), instead of the existing formulation of dimension (2n + 1), for n-dimensional load flow equations. This feature makes computation of the maximum loading points very inexpensive in comparison with those required in the existing formulation. A theoretical basis for the new formulation is provided. The new problem formulation is derived by using a simple reparameterization scheme and exploiting the special properties of the power flow model. Moreover, the proposed test function is shown to be monotonic in the vicinity of a maximum loading point. Therefore, it allows one to monitor the approach to maximum loading points during the solution search process. Simulation results on a 234-bus system are presented.

  7. Acoustic Space Dimensionality Selection and Combination using the Maximum Entropy Principle 

    E-Print Network [OSTI]

    Abdel-Haleem, Yasser H; Renals, Steve; Lawrence, Neil D

    2004-01-01T23:59:59.000Z

    In this paper we propose a discriminative approach to acoustic space dimensionality selection based on maximum entropy modelling. We form a set of constraints by composing the acoustic space with the space of phone classes, and use a continuous...

  8. An Analysis of Maximum Residential Energy Efficiency in Hot and Humid Climates 

    E-Print Network [OSTI]

    Malhotra, M.; Haberl, J. S.

    2006-01-01T23:59:59.000Z

    Systems in Hot and Humid Climates, Orlando, Florida, July 24-26, 2006 Methodology 1. Development of the Basecase Simulation Model 2. Analysis of Energy Saving Measures 3. Development of the Maximum Energy-Efficient House 4. Economic Analysis DOE-2 Input...AN ANALYSIS OF MAXIMUM RESIDENTIAL ENERGY EFFICIENCY IN HOT AND HUMID CLIMATES Mini Malhotra Graduate Research Assistant Jeff Haberl, Ph.D., P.E. Professor/Associate Director Energy Systems Laboratory, Texas A&M University College...

  9. ON THE PROBLEM OF UNIQUENESS FOR THE MAXIMUM STIRLING NUMBER(S) OF THE SECOND KIND

    E-Print Network [OSTI]

    Pomerance, Carl

    ON THE PROBLEM OF UNIQUENESS FOR THE MAXIMUM STIRLING NUMBER(S) OF THE SECOND KIND E. Rodney Say that an integer n is exceptional if the maximum Stirling number of the second kind S(n, k) occurs or equal to x is O(x3/5+ ), for any > 0. 1. Introduction Let S(n, k) be the Stirling number of the second

  10. A stochastic model for sediment yield using the Principle of Maximum Entropy

    E-Print Network [OSTI]

    Singh, V. P.; Krstanovic, P. F.

    WATER RESOURCES RESEARCH, VOL. 23, NO. 5, PAGES 781-793, MAY 1987 A Stochastic Model for Sediment Yield Using the Principle of Maximum Entropy V. P. SINGH AND P. F. KRSTANOVIC Department of Civil Engineering, Louisiana State University, Baton... Rouge The principle of maximum entropy was applied to derive a stochastic model for sediment yield from upland watersheds. By maximizing the conditional entropy subject to certain constraints, a probability distribution of sediment yield conditioned...

  11. arthritis forty-eight-week efficacy: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    poor localities influence the capacity for community efficacy. Through a multivariate analysis using 497 households in poor localities of Addis Ababa, we investigate how social...

  12. assessor-blind comparative efficacy: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    variations in poor localities influence the capacity for community efficacy. Through a multivariate analysis using 497 households in poor localities of Addis Ababa, we...

  13. Mechanisms of NDV-3 vaccine efficacy in MRSA skin versus invasive infection

    E-Print Network [OSTI]

    2014-01-01T23:59:59.000Z

    3 vaccine efficacy in MRSA skin versus invasive infectionFig. 1) and suppression of MRSA proliferation (Fig. 2). Eachseverity and suppression of MRSA bioluminescence (Figs. 1

  14. Heterogeneity-corrected vs -uncorrected critical structure maximum point doses in breast balloon brachytherapy

    SciTech Connect (OSTI)

    Kim, Leonard, E-mail: kimlh@umdnj.edu [Department of Radiation Oncology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (United States); Narra, Venkat; Yue, Ning [Department of Radiation Oncology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (United States)

    2013-07-01T23:59:59.000Z

    Recent studies have reported potentially clinically meaningful dose differences when heterogeneity correction is used in breast balloon brachytherapy. In this study, we report on the relationship between heterogeneity-corrected and -uncorrected doses for 2 commonly used plan evaluation metrics: maximum point dose to skin surface and maximum point dose to ribs. Maximum point doses to skin surface and ribs were calculated using TG-43 and Varian Acuros for 20 patients treated with breast balloon brachytherapy. The results were plotted against each other and fit with a zero-intercept line. Max skin dose (Acuros) = max skin dose (TG-43) ? 0.930 (R{sup 2} = 0.995). The average magnitude of difference from this relationship was 1.1% (max 2.8%). Max rib dose (Acuros) = max rib dose (TG-43) ? 0.955 (R{sup 2} = 0.9995). The average magnitude of difference from this relationship was 0.7% (max 1.6%). Heterogeneity-corrected maximum point doses to the skin surface and ribs were proportional to TG-43-calculated doses. The average deviation from proportionality was 1%. The proportional relationship suggests that a different metric other than maximum point dose may be needed to obtain a clinical advantage from heterogeneity correction. Alternatively, if maximum point dose continues to be used in recommended limits while incorporating heterogeneity correction, institutions without this capability may be able to accurately estimate these doses by use of a scaling factor.

  15. Sloan Digital Sky Survey Spectroscopic Lens Search. I. Discovery of Intermediate-Redshift Star-Forming Galaxies Behind Foreground Luminous Red Galaxies

    E-Print Network [OSTI]

    Adam S. Bolton; Scott Burles; David J. Schlegel; Daniel J. Eisenstein; J. Brinkmann

    2004-03-16T23:59:59.000Z

    We present a catalog of 49 spectroscopic strong gravitational lens candidates selected from a Sloan Digital Sky Survey sample of 50996 luminous red galaxies. Potentially lensed star-forming galaxies are detected through the presence of background oxygen and hydrogen nebular emission lines in the spectra of these massive foreground galaxies. This multiline selection eliminates the ambiguity of single-line identification and provides a very promising sample of candidate galaxy-galaxy lens systems at low to intermediate redshift, with foreground redshifts ranging from 0.16 to 0.49 and background redshifts from 0.25 to 0.81. Any lenses confirmed within our sample would be important new probes of early-type galaxy mass distributions, providing complementary constraints to those obtained from currently known lensed high-redshift quasars.

  16. LUMINOUS SUPERNOVA-LIKE UV/OPTICAL/INFRARED TRANSIENTS ASSOCIATED WITH ULTRA-LONG GAMMA-RAY BURSTS FROM METAL-POOR BLUE SUPERGIANTS

    SciTech Connect (OSTI)

    Kashiyama, Kazumi; Yajima, Hidenobu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Nakauchi, Daisuke; Nakamura, Takashi [Department of Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Suwa, Yudai, E-mail: kzk15@psu.edu [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-06-10T23:59:59.000Z

    Metal-poor massive stars typically end their lives as blue supergiants (BSGs). Gamma-ray bursts (GRBs) from such progenitors could have an ultra-long duration of relativistic jets. For example, Population III (Pop III) GRBs at z {approx} 10-20 might be observable as X-ray-rich events with a typical duration of T{sub 90} {approx} 10{sup 4}(1 + z) s. The recent GRB111209A at z = 0.677 has an ultra-long duration of T{sub 90} {approx} 2.5 Multiplication-Sign 10{sup 4} s and it has been suggested that its progenitor might have been a metal-poor BSG in the local universe. Here, we suggest that luminous UV/optical/infrared emission is associated with this new class of GRBs from metal-poor BSGs. Before the jet head breaks out of the progenitor envelope, the energy injected by the jet is stored in a hot plasma cocoon, which finally emerges and expands as a baryon-loaded fireball. We show that the photospheric emissions from the cocoon fireball could be intrinsically very bright (L{sub peak} {approx} 10{sup 42}-10{sup 44} erg s{sup -1}) in UV/optical bands ({epsilon}{sub peak} {approx} 10 eV) with a typical duration of {approx}100 days in the rest frame. Such cocoon emissions from Pop III GRBs might be detectable in infrared bands at {approx}years after Pop III GRBs at up to z {approx} 15 by upcoming facilities such as the James Webb Space Telescope. We also suggest that GRB111209A might have been rebrightening in UV/optical bands up to an AB magnitude of {approx}< 26. The cocoon emission from local metal-poor BSGs might have been observed previously as luminous supernovae without GRBs since they can be seen from the off-axis direction of the jet.

  17. V-ATPase-dependent luminal acidification is required for endocytic recycling of a yeast cell wall stress sensor, Wsc1p

    SciTech Connect (OSTI)

    Ueno, Kazuma; Saito, Mayu; Nagashima, Makiko; Kojima, Ai; Nishinoaki, Show [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan)] [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Toshima, Junko Y., E-mail: yama_jun@aoni.waseda.jp [Faculty of Science and Engineering, Waseda University, Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480 (Japan); Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Toshima, Jiro, E-mail: jtosiscb@rs.noda.tus.ac.jp [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan) [Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan); Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan)

    2014-01-10T23:59:59.000Z

    Highlights: •A targeted genome screen identified 5 gene groups affecting Wsc1p recycling. •V-ATPase-dependent luminal acidification is required for Wsc1p recycling. •Activity of V-ATPase might be required for cargo recognition by the retromer complex. -- Abstract: Wsc1p is a major cell wall sensor protein localized at the polarized cell surface. The localization of Wsc1p is maintained by endocytosis and recycling from endosomes back to the cell surface, but changes to the vacuole when cells are subjected to heat stress. Exploiting this unique property of Wsc1p, we screened for yeast single-gene deletion mutants exhibiting defects in Wsc1p trafficking. By expressing 3GFP-tagged Wsc1p in mutants with deleted genes whose function is related to intracellular trafficking, we identified 5 gene groups affecting Wsc1p trafficking, impaired respectively in endocytic internalization, multivesicular body sorting, the GARP complex, endosomal maturation/vacuolar fusion, and V-ATPase. Interestingly, deletion of the VPH1 gene, encoding the V{sub o} subunit of vacuolar-type H{sup +}-ATPase (V-ATPase), led to mis-localization of Wsc1p from the plasma membrane to the vacuole. In addition, disruption of other V-ATPase subunits (vma mutants) also caused defects of Wsc1p trafficking and vacuolar acidification similar to those seen in the vph1? mutant. Moreover, we found that deletion of the VPS26 gene, encoding a subunit of the retromer complex, also caused a defect in Wsc1p recycling and mis-localization of Wsc1p to the vacuole. These findings clarified the previously unidentified Wsc1p recycling pathway and requirement of V-ATPase-dependent luminal acidification for Wsc1p recycling.

  18. SN 2013ej in M74: A Luminous and Fast-declining Type II-P Supernova

    E-Print Network [OSTI]

    Huang, Fang; Zhang, Jujia; Brown, Peter J; Zampieri, Luca; Pumo, Maria Letizia; Zhang, Tianmeng; Chen, Juncheng; Mo, Jun; Zhao, Xulin

    2015-01-01T23:59:59.000Z

    We present extensive ultraviolet, optical, and near-infrared observations of the type IIP supernova (SN IIP) 2013ej in the nearby spiral galaxy M74. The multicolor light curves, spanning from $\\sim$ 8--185 days after explosion, show that it has a higher peak luminosity (i.e., M$_{V}$ $\\sim$$-$17.83 mag at maximum light), a faster post-peak decline, and a shorter plateau phase (i.e., $\\sim$ 50 days) compared to the normal type IIP SN 1999em. The mass of $^{56}$Ni is estimated as 0.02$\\pm$0.01 M$_{\\odot}$ from the radioactive tail of the bolometric light curve. The spectral evolution of SN 2013ej is similar to that of SN 2004et and SN 2007od, but shows a larger expansion velocity (i.e., $v_{Fe II} \\sim$ 4600 km s$^{-1}$ at t $\\sim$ 50 days) and broader line profiles. In the nebular phase, the emission of H$\\alpha$ line displays a double-peak structure, perhaps due to the asymmetric distribution of $^{56}$Ni produced in the explosion. With the constraints from the main observables such as bolometric light curve,...

  19. Period-luminosity and period-luminosity-colour relations for Mira variables at maximum light

    E-Print Network [OSTI]

    S. M. Kanbur; M. A. Hendry; D. Clarke

    1997-04-14T23:59:59.000Z

    In this paper we confirm the existence of period-luminosity (PL) and period-luminosity-colour (PLC) relations at maximum light for O and C Mira variables in the LMC. We demonstrate that in the J and H bands the maximum light PL relations have a significantly smaller dispersion than their counterparts at mean light, while the K band and bolometric PL relations have a dispersion comparable to that at mean light. In the J, H and K bands the fitted PL relations for the O Miras are found to have smaller dispersion than those for the C Miras, at both mean and maximum light, while the converse is true for the relations based on bolometric magnitudes. The inclusion of a non-zero log period term is found to be highly significant in all cases except that of the C Miras in the J band, for which the data are found to be consistent with having constant absolute magnitude. This suggests the possibility of employing C Miras as standard candles. We suggest both a theoretical justification for the existence of Mira PL relations at maximum light and a possible explanation of why these relations should have a smaller dispersion than at mean light. The existence of such maximum light relations offers the possibility of extending the range and improving the accuracy of the Mira distance scale to Galactic globular clusters and to other galaxies.

  20. HFIR Vessel Maximum Permissible Pressures for Operating Period 26 to 50 EFPY (100 MW)

    SciTech Connect (OSTI)

    Cheverton, R.D.; Inger, J.R.

    1999-01-01T23:59:59.000Z

    Extending the life of the HFIR pressure vessel from 26 to 50 EFPY (100 MW) requires an updated calculation of the maximum permissible pressure for a range in vessel operating temperatures (40-120 F). The maximum permissible pressure is calculated using the equal-potential method, which takes advantage of knowledge gained from periodic hydrostatic proof tests and uses the test conditions (pressure, temperature, and frequency) as input. The maximum permissible pressure decreases with increasing time between hydro tests but is increased each time a test is conducted. The minimum values that occur just prior to a test either increase or decrease with time, depending on the vessel temperature. The minimum value of these minimums is presently specified as the maximum permissible pressure. For three vessel temperatures of particular interest (80, 88, and 110 F) and a nominal time of 3.0 EFPY(100 MVV)between hydro tests, these pressures are 677, 753, and 850 psi. For the lowest temperature of interest (40 F), the maximum permissible pressure is 295 psi.

  1. A Highly Efficacious Lymphocyte Chemoattractant, Stromal Cell-derived Factor 1 (SDF-1)

    E-Print Network [OSTI]

    Springer, Timothy A.

    A Highly Efficacious Lymphocyte Chemoattractant, Stromal Cell-derived Factor 1 (SDF-1) By Conrad C-derived factor 1 (SDF-1). SDF-1 acts on lymphocytes and monocytes but not neutrophils in vitro and is both a highly efficacious and highly potent mononuclear cell attractant in vivo. In addition, SDF-1 induces

  2. Spectral Modeling of SNe Ia Near Maximum Light: Probing the Characteristics of Hydro Models

    E-Print Network [OSTI]

    E. Baron; S. Bongard; David Branch; Peter H. Hauschildt

    2006-03-03T23:59:59.000Z

    We have performed detailed NLTE spectral synthesis modeling of 2 types of 1-D hydro models: the very highly parameterized deflagration model W7, and two delayed detonation models. We find that overall both models do about equally well at fitting well observed SNe Ia near to maximum light. However, the Si II 6150 feature of W7 is systematically too fast, whereas for the delayed detonation models it is also somewhat too fast, but significantly better than that of W7. We find that a parameterized mixed model does the best job of reproducing the Si II 6150 line near maximum light and we study the differences in the models that lead to better fits to normal SNe Ia. We discuss what is required of a hydro model to fit the spectra of observed SNe Ia near maximum light.

  3. Fast singular value decomposition combined maximum entropy method for plasma tomography

    SciTech Connect (OSTI)

    Kim, Junghee; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701(Korea, Republic of)

    2006-02-15T23:59:59.000Z

    The maximum entropy method (MEM) is a widely used reconstruction algorithm in plasma physics. Drawbacks of the conventional MEM are its heavy time-consuming process and possible generation of noisy reconstruction results. In this article, a modified maximum entropy algorithm is described which speeds up the calculation and shows better noise handling capability. Similar to the rapid minimum Fisher information method, the modified maximum entropy algorithm uses simple matrix operations instead of treating a fully nonlinear problem. The preprocess for rapid tomographic calculation is based on the vector operations and the singular value decomposition (SVD). The initial guess of the sought-for emissivity is calculated by SVD and this helped reconstruction about ten times faster than the conventional MEM. Therefore, the developed fast MEM can be used for intershot tomographic analyses of fusion plasmas.

  4. Estimating the maximum potential revenue for grid connected electricity storage : arbitrage and regulation.

    SciTech Connect (OSTI)

    Byrne, Raymond Harry; Silva Monroy, Cesar Augusto.

    2012-12-01T23:59:59.000Z

    The valuation of an electricity storage device is based on the expected future cash ow generated by the device. Two potential sources of income for an electricity storage system are energy arbitrage and participation in the frequency regulation market. Energy arbitrage refers to purchasing (stor- ing) energy when electricity prices are low, and selling (discharging) energy when electricity prices are high. Frequency regulation is an ancillary service geared towards maintaining system frequency, and is typically procured by the independent system operator in some type of market. This paper outlines the calculations required to estimate the maximum potential revenue from participating in these two activities. First, a mathematical model is presented for the state of charge as a function of the storage device parameters and the quantities of electricity purchased/sold as well as the quantities o ered into the regulation market. Using this mathematical model, we present a linear programming optimization approach to calculating the maximum potential revenue from an elec- tricity storage device. The calculation of the maximum potential revenue is critical in developing an upper bound on the value of storage, as a benchmark for evaluating potential trading strate- gies, and a tool for capital nance risk assessment. Then, we use historical California Independent System Operator (CAISO) data from 2010-2011 to evaluate the maximum potential revenue from the Tehachapi wind energy storage project, an American Recovery and Reinvestment Act of 2009 (ARRA) energy storage demonstration project. We investigate the maximum potential revenue from two di erent scenarios: arbitrage only and arbitrage combined with the regulation market. Our analysis shows that participation in the regulation market produces four times the revenue compared to arbitrage in the CAISO market using 2010 and 2011 data. Then we evaluate several trading strategies to illustrate how they compare to the maximum potential revenue benchmark. We conclude with a sensitivity analysis with respect to key parameters.

  5. What is the maximum rate at which entropy of a string can increase?

    SciTech Connect (OSTI)

    Ropotenko, Kostyantyn [State Administration of Communications, Ministry of Transport and Communications of Ukraine 22, Khreschatyk, 01001, Kyiv (Ukraine)

    2009-03-15T23:59:59.000Z

    According to Susskind, a string falling toward a black hole spreads exponentially over the stretched horizon due to repulsive interactions of the string bits. In this paper such a string is modeled as a self-avoiding walk and the string entropy is found. It is shown that the rate at which information/entropy contained in the string spreads is the maximum rate allowed by quantum theory. The maximum rate at which the black hole entropy can increase when a string falls into a black hole is also discussed.

  6. Hydrodynamic Relaxation of an Electron Plasma to a Near-Maximum Entropy State

    SciTech Connect (OSTI)

    Rodgers, D. J.; Servidio, S.; Matthaeus, W. H.; Mitchell, T. B.; Aziz, T. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Montgomery, D. C. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States)

    2009-06-19T23:59:59.000Z

    Dynamical relaxation of a pure electron plasma in a Malmberg-Penning trap is studied, comparing experiments, numerical simulations and statistical theories of weakly dissipative two-dimensional (2D) turbulence. Simulations confirm that the dynamics are approximated well by a 2D hydrodynamic model. Statistical analysis favors a theoretical picture of relaxation to a near-maximum entropy state with constrained energy, circulation, and angular momentum. This provides evidence that 2D electron fluid relaxation in a turbulent regime is governed by principles of maximum entropy.

  7. Maximum-Entropy Closures for Kinetic Theories of Neuronal Network Dynamics

    SciTech Connect (OSTI)

    Rangan, Aaditya V.; Cai, David [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)

    2006-05-05T23:59:59.000Z

    We analyze (1+1)D kinetic equations for neuronal network dynamics, which are derived via an intuitive closure from a Boltzmann-like equation governing the evolution of a one-particle (i.e., one-neuron) probability density function. We demonstrate that this intuitive closure is a generalization of moment closures based on the maximum-entropy principle. By invoking maximum-entropy closures, we show how to systematically extend this kinetic theory to obtain higher-order (1+1)D kinetic equations and to include coupled networks of both excitatory and inhibitory neurons.

  8. Maximum Entropy Models of Shortest Path and Outbreak Distributions in Networks

    E-Print Network [OSTI]

    Bauckhage, Christian; Hadiji, Fabian

    2015-01-01T23:59:59.000Z

    Properties of networks are often characterized in terms of features such as node degree distributions, average path lengths, diameters, or clustering coefficients. Here, we study shortest path length distributions. On the one hand, average as well as maximum distances can be determined therefrom; on the other hand, they are closely related to the dynamics of network spreading processes. Because of the combinatorial nature of networks, we apply maximum entropy arguments to derive a general, physically plausible model. In particular, we establish the generalized Gamma distribution as a continuous characterization of shortest path length histograms of networks or arbitrary topology. Experimental evaluations corroborate our theoretical results.

  9. Measuring the Efficacy of Leaders to Assess Information and Make Decisions in a Crisis: The C-LEAD Scale

    E-Print Network [OSTI]

    Pittinsky, Todd L.

    2009-07-01T23:59:59.000Z

    Based on literature and expert interviews, we developed the Crisis Leader Efficacy in Assessing and Deciding scale (C-LEAD) to capture the efficacy of leaders to assess information and make decisions in a public health and ...

  10. NOAA Technical Memorandum NWS HYDRO 39 PROBABLE MAXIMUM PRECIPITATION FOR THE UPPER

    E-Print Network [OSTI]

    NOAA Technical Memorandum NWS HYDRO 39 PROBABLE MAXIMUM PRECIPITATION FOR THE UPPER DEERFIELD RIVER The Office of Hydrology (HYDRO) of the National Weather Service (NWS) develops procedures for making river agencies, and conducts pertinent research and development. NOAA Technical Memorandums in the NWS HYDRO

  11. Analysis and Optimization of Maximum Power Point Tracking Algorithms in the Presence of

    E-Print Network [OSTI]

    Odam, Kofi

    , Charles R. Sullivan, Senior Member, IEEE Abstract--This paper analyzes the effect of noise on sev- eral maximum power point tracking (MPPT) algorithms for photovoltaic systems. Noise is an essential of the signals, mitigating the noise. The effect of noise and other parameters on tracking performance

  12. Maximum Output Amplitude of Linear Systems for certain Input Constraints1

    E-Print Network [OSTI]

    Sontag, Eduardo

    of this input and calculates the maximum amplitude of the output. The solution of this problem is a necessary, Linear Sys- tems. 1 Introduction and Motivation Most practical control problems are dominated by hard bounds. Valves can only be operated between fully open and fully closed, pumps and compressors have

  13. Blind Equalization via Approximate Maximum Likelihood Source Seungjin CHOI x1 and Andrzej CICHOCKI y

    E-Print Network [OSTI]

    Choi, Seungjin

    Blind Equalization via Approximate Maximum Likelihood Source Separation Seungjin CHOI x1, RIKEN 2-1 Hirosawa, Wako-shi Saitama 351-0198, JAPAN Abstract Blind equalization of single input multiple output (SIMO) FIR channels can be refor- mulated as the problem of blind source separation

  14. Photothermoacoustic imaging of biological tissues: maximum depth characterization comparison of time and

    E-Print Network [OSTI]

    Mandelis, Andreas

    Photothermoacoustic imaging of biological tissues: maximum depth characterization comparison for Advanced Diffusion-Wave Technologies Department of Mechanical and Industrial Engineering 5 King's College induced in light-absorbing materials can be observed either as a transient signal in time domain

  15. Radiative Impacts on the Growth of Drops within Simulated Marine Stratocumulus. Part I: Maximum Solar Heating

    E-Print Network [OSTI]

    Harrington, Jerry Y.

    Radiative Impacts on the Growth of Drops within Simulated Marine Stratocumulus. Part I: Maximum Solar Heating CHRISTOPHER M. HARTMAN AND JERRY Y. HARRINGTON Department of Meteorology, The Pennsylvania November 2004) ABSTRACT The effects of solar heating and infrared cooling on the vapor depositional growth

  16. Maximum principle and bang-bang property of time optimal controls for Schrodinger type systems

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Maximum principle and bang-bang property of time optimal controls for Schr¨odinger type systems J conditions for the bang- bang property of optimal controls. The results are then applied to some systems-Bang property, Schr¨odinger equation 1 Introduction Time optimal control is a classical problem for linear

  17. Recursive maximum likelihood estimation for structural health monitoring: Kalman and particle filter implementations

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Recursive maximum likelihood estimation for structural health monitoring: Kalman and particle by a likelihood approach. In a first part the structural health monitoring problem is written in term of recursive al [6] in a more simple framework. Particle approximation for health monitoring was already proposed

  18. Maximum-Power-Point Tracking Method of Photovoltaic Power System Using Single Transducer

    E-Print Network [OSTI]

    Fujimoto, Hiroshi

    Maximum-Power-Point Tracking Method of Photovoltaic Power System Using Single Transducer Toshihiko) method of a photovoltaic power system with less transducer count. A unique feature of this method concern on an environmental issue since 1990's. Above all, a photovoltaic power generation system is one

  19. Design of wind farm layout for maximum wind energy capture Andrew Kusiak*, Zhe Song

    E-Print Network [OSTI]

    Kusiak, Andrew

    Design of wind farm layout for maximum wind energy capture Andrew Kusiak*, Zhe Song Intelligent Accepted 24 August 2009 Available online 22 September 2009 Keywords: Wind farm Wind turbine Layout design Optimization Evolutionary algorithms Operations research a b s t r a c t Wind is one of the most promising

  20. Electrical Estimation of Conditional Probability for Maximum-likelihood Based PMD Mitigation

    E-Print Network [OSTI]

    Zweck, John

    Xi, T¨ulay Adali, and John Zweck Department of Computer Science and Electrical Engineering UniversityElectrical Estimation of Conditional Probability for Maximum-likelihood Based PMD Mitigation Wenze probability density functions in the presence of both all-order PMD and ASE noise are estimated electronically

  1. Brayton Cycles: From the ...rst law, the maximum transfers for component SSSF control volumes are

    E-Print Network [OSTI]

    . For the simple reversible Brayton cycle of given pressure ratio rp $ (p2=p1) = (p3=p4) [compare Example 9.4, pp is higher than 1 r (2=7) . For the ideal regenerator, the thermal e¢ ciency approaches the Carnot-cycle eBrayton Cycles: From the ...rst law, the maximum transfers for component SSSF control volumes are w

  2. Maximum Likelihood Estimation of Mixture Densities for Binned and Truncated Multivariate

    E-Print Network [OSTI]

    Smyth, Padhraic

    Maximum Likelihood Estimation of Mixture Densities for Binned and Truncated Multivariate Data in data analysis and machine learning. This paper addresses the problem of fitting mixture densities to multivariate binned and truncated data. The EM approach proposed by McLachlan and Jones (1988

  3. EXTENSION OF THE MAXIMUM POWER REGION OF DOUBLY-SALIENT VARIABLE RELUCTANCE MOTORS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -Salient Variable Reluctance Motors (DSVRM) has been investigated and developed for variable-speed drives during, variable-frequency generators, wind wheels, machine tools, etc.). In these applications, it is generally necessary to operate in a regime of a high speed ux-weakening (zone of maximum constant power), for a better

  4. Hydrogen Molecules inside Fullerene C70: Quantum Dynamics, Energetics, Maximum Occupancy, And Comparison with C60

    E-Print Network [OSTI]

    Turro, Nicholas J.

    Hydrogen Molecules inside Fullerene C70: Quantum Dynamics, Energetics, Maximum Occupancy of Chemistry, New York UniVersity, New York, New York 10003, Department of Chemistry, Brown UniVersity, ProVidence, Rhode Island 02912, and Department of Chemistry, Columbia UniVersity, New York, New York 10027 Received

  5. Exact Maximum Likelihood estimator for the BL-GARCH model under elliptical distributed

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Exact Maximum Likelihood estimator for the BL-GARCH model under elliptical distributed innovations, Brisbane QLD 4001, Australia Abstract We are interested in the parametric class of Bilinear GARCH (BL-GARCH examine, in this paper, the BL-GARCH model in a general setting under some non-normal distributions. We

  6. Learning with MaximumEntropy Distributions \\Lambda Yishay Mansour Mariano Schain

    E-Print Network [OSTI]

    Mansour, Yishay

    Learning with Maximum­Entropy Distributions \\Lambda Yishay Mansour Mariano Schain Computer Science Dept. Tel­Aviv University fmansour,marianog@math.tau.ac.il Abstract We are interested in distributions which are de­ rived as a maximumentropy distribution given a set of constraints. More specifically, we

  7. A Global Maximum Power Point Tracking Method for PV Module Integrated Converters

    E-Print Network [OSTI]

    Liberzon, Daniel

    with large arrays of series-connected PV mod- ules connected to a central inverter. Figure 1(a) depicts, it is conceivable that these systems do not extract the maximum possible power from the PV array when individual PV to partial shading. In such systems, power electronics circuits are integrated directly with PV modules

  8. Department of Mechanical Engineering Spring 2013 Maximum Allowable Gasket Seating Surface Degradation

    E-Print Network [OSTI]

    Demirel, Melik C.

    Degradation Overview Westinghouse applies a conservative approach when evaluating degradation on a gasket evaluation. The team was tasked with collecting this data to determine when degradation endangers the pressure seal. Objectives The team's objectives were to determine the maximum degradation which the gasket

  9. Benefits of the International Residential Code's Maximum Solar heat Gain Coefficient Requirement for Windows

    E-Print Network [OSTI]

    Stone, G. A.; DeVito, E. M.; Nease, N. H.

    2002-01-01T23:59:59.000Z

    Texas adopted in its residential building energy code a maximum 0.40 solar heat gain coefficient (SHGC) for fenestration (e.g., windows, glazed doors and skylights)-a critical driver of cooling energy use, comfort and peak demand. An analysis...

  10. Bayesian Data and Channel Joint Maximum-Likelihood Based Error Correction in Wireless Sensor Networks

    E-Print Network [OSTI]

    Jagannatham, Aditya K.

    in wireless sensor networks (WSN). The proposed algo- rithm employs the temporal correlation of the narrowband Wireless Sensor Network (WSN), Likelihood, Sphere De- coder 1. INTRODUCTION Wireless Sensor Networks (WSNBayesian Data and Channel Joint Maximum-Likelihood Based Error Correction in Wireless Sensor

  11. Maximum-Lifetime Multi-Channel Routing in Wireless Sensor Networks

    E-Print Network [OSTI]

    Nasipuri, Asis

    Maximum-Lifetime Multi-Channel Routing in Wireless Sensor Networks Amitangshu Pal and Asis Nasipuri and routing problem in multi-channel wireless sensor networks for maximizing the worst case network lifetime solution for the problem. Keywords: Wireless sensor networks, multi-channel rout- ing, distributed

  12. The chronology of the Last Glacial Maximum and deglacial events in central Argentine Patagonia

    E-Print Network [OSTI]

    The chronology of the Last Glacial Maximum and deglacial events in central Argentine Patagonia and deglaciation in the Lago Pueyrredo´n valley of central Patagonia, 47.5 S, Argentina. The valley was a major and the onset of deglaciation occurred broadly synchronously throughout Patagonia. Deglaciation resulted

  13. Single-machine scheduling with periodic and exible periodic maintenance to minimize maximum tardiness

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    periods often appear in industry due to a machine breakdown (stochastic) or preventive maintenance of machine unavailability. However, in some cases (e.g. preventive maintenance), the maintenance of a machineSingle-machine scheduling with periodic and exible periodic maintenance to minimize maximum

  14. THE SECOND LAW OF THERMODYNAMICS AND THE GLOBAL CLIMATE SYSTEM: A REVIEW OF THE MAXIMUM

    E-Print Network [OSTI]

    Lorenz, Ralph D.

    to absorption of solar radiation in the climate system is found to be irrelevant to the maximized prop- erties from hot to cold places, thereby producing the kinetic energy of the fluid itself. His generalTHE SECOND LAW OF THERMODYNAMICS AND THE GLOBAL CLIMATE SYSTEM: A REVIEW OF THE MAXIMUM ENTROPY

  15. Hydraulic limits on maximum plant transpiration and the emergence of the safetyefficiency trade-off

    E-Print Network [OSTI]

    Jackson, Robert B.

    Hydraulic limits on maximum plant transpiration and the emergence of the safety­efficiency trade.12126 Key words: hydraulic limitation, safety­ efficiency trade-off, soil­plant­atmosphere model, trait hydraulics constrain ecosystem productivity by setting physical limits to water transport and hence carbon

  16. Performance of Photovoltaic Maximum Power Point Tracking Algorithms in the Presence of Noise

    E-Print Network [OSTI]

    Odam, Kofi

    Performance of Photovoltaic Maximum Power Point Tracking Algorithms in the Presence of Noise tracking (MPPT) algorithms for photovoltaic systems, including how noise affects both tracking speed-performance photovoltaic sys- tems. An intelligent controller adjusts the voltage, current, or impedance seen by a solar

  17. PHYSICAL REVIEW E 86, 041144 (2012) Efficiency at maximum power for classical particle transport

    E-Print Network [OSTI]

    Lindenberg, Katja

    2012-01-01T23:59:59.000Z

    PHYSICAL REVIEW E 86, 041144 (2012) Efficiency at maximum power for classical particle transport transport. DOI: 10.1103/PhysRevE.86.041144 PACS number(s): 05.70.Ln, 05.40.-a, 05.20.-y I. INTRODUCTION Over, operating between a hot and cold bath at temperatures T (1) and T (2) , respectively, possesses universal

  18. Optimization of stomatal conductance for maximum carbon gain under dynamic soil moisture

    E-Print Network [OSTI]

    Katul, Gabriel

    Optimization of stomatal conductance for maximum carbon gain under dynamic soil moisture Stefano Accepted 26 September 2013 Available online 9 October 2013 Keywords: Optimization Photosynthesis Soil moisture Stomatal conductance Transpiration a b s t r a c t Optimization theories explain a variety

  19. A Distributed Approach to Maximum Power Point Tracking for Photovoltaic Sub-Module Differential

    E-Print Network [OSTI]

    Liberzon, Daniel

    of the proposed distributed algorithm. I. INTRODUCTION IN photovoltaic (PV) energy systems, PV modules are often of the system, small size and low power ratings of the power electronics circuit components. Due1 A Distributed Approach to Maximum Power Point Tracking for Photovoltaic Sub-Module Differential

  20. An Analysis of the Maximum Drawdown Risk Malik Magdon-Ismail

    E-Print Network [OSTI]

    Magdon-Ismail, Malik

    Engineering Cairo University Giza, Egypt. amir@alumni.caltech.edu Introduction. The maximum cumulative loss to the Calmar ratio is the Sterling ratio, Sterling(T) = Return over [0,T ] MDD over [0,T ]-10% , and our discussion applies equally well to the Sterling ratio. 1 #12;primarily due to a lack of an analytical

  1. An Analysis of the Maximum Drawdown Risk Malik MagdonIsmail

    E-Print Network [OSTI]

    Magdon-Ismail, Malik

    Engineering Cairo University Giza, Egypt. amir@alumni.caltech.edu Introduction. The maximum cumulative loss is not prevalent 1 Similar to the Calmar ratio is the Sterling ratio, Sterling(T ) = Return over [0,T ] MDD over [0,T ]-10% , and our discussion applies equally well to the Sterling ratio. 1 #12; primarily due

  2. Extraction of Spectral Functions from Dyson-Schwinger Studies via the Maximum Entropy Method

    E-Print Network [OSTI]

    Dominik Nickel

    2006-07-20T23:59:59.000Z

    It is shown how to apply the Maximum Entropy Method (MEM) to numerical Dyson-Schwinger studies for the extraction of spectral functions of correlators from their corresponding Euclidean propagators. Differences to the application in lattice QCD are emphasized and, as an example, the spectral functions of massless quarks in cold and dense matter are presented.

  3. Parameters estimation for spatio-temporal maximum entropy distributions: application to neural spike trains

    E-Print Network [OSTI]

    Nasser, Hassan

    2014-01-01T23:59:59.000Z

    We propose a numerical method to learn Maximum Entropy (MaxEnt) distributions with spatio-temporal constraints from experimental spike trains. This is an extension of two papers [10] and [4] who proposed the estimation of parameters where only spatial constraints were taken into account. The extension we propose allows to properly handle memory effects in spike statistics, for large sized neural networks.

  4. Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensembles out of equilibrium Gavin E. Crooks*

    E-Print Network [OSTI]

    Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensembles out of equilibrium Gavin E at equilibrium? Here, we argue the most appropriate additional parameter is the nonequilibrium entropy of ways that the same system can be out of equilibrium. That the equilibrium entropy is maximized given

  5. Extraction of spectral functions from Dyson-Schwinger studies via the maximum entropy method

    SciTech Connect (OSTI)

    Nickel, Dominik [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)]. E-mail: dominik.nickel@physik.tu-darmstadt.de

    2007-08-15T23:59:59.000Z

    It is shown how to apply the Maximum Entropy Method (MEM) to numerical Dyson-Schwinger studies for the extraction of spectral functions of correlators from their corresponding Euclidean propagators. Differences to the application in lattice QCD are emphasized and, as an example, the spectral functions of massless quarks in cold and dense matter are presented.

  6. Lattice Field Theory with the Sign Problem and the Maximum Entropy Method

    E-Print Network [OSTI]

    Masahiro Imachi; Yasuhiko Shinno; Hiroshi Yoneyama

    2007-02-09T23:59:59.000Z

    Although numerical simulation in lattice field theory is one of the most effective tools to study non-perturbative properties of field theories, it faces serious obstacles coming from the sign problem in some theories such as finite density QCD and lattice field theory with the $\\theta$ term. We reconsider this problem from the point of view of the maximum entropy method.

  7. Relating maximum airway dilation and subsequent reconstriction to reactivity in human lungs

    E-Print Network [OSTI]

    Lutchen, Kenneth

    Relating maximum airway dilation and subsequent reconstriction to reactivity in human lungs Lauren in human lungs. J Appl Physiol 96: 1808­1814, 2004. First published February 6, 2004; 10.1152/japplphysiol reactivity in healthy lungs by prohibiting DI for an extended period. The present study had two goals. First

  8. Self-Leadership, Self-Efficacy, and Academic Performance in Undergraduate Students and Peer Mentors Lauren M Bouchard1

    E-Print Network [OSTI]

    Zhou, Yaoqi

    Self-Leadership, Self-Efficacy, and Academic Performance in Undergraduate Students and Peer Mentors of self-leadership and self-efficacy on the academic performance of students--specifically academic peer of self-leadership and self-efficacy as well as in general academic performance. Self-leadership

  9. SALTSTONE DISPOSAL FACILITY: DETERMINATION OF THE PROBABLE MAXIMUM WATER TABLE ELEVATION

    SciTech Connect (OSTI)

    Hiergesell, R

    2005-04-01T23:59:59.000Z

    A coverage depicting the configuration of the probable maximum water table elevation in the vicinity of the Saltstone Disposal Facility (SDF) was developed to support the Saltstone program. This coverage is needed to support the construction of saltstone vaults to assure that they remain above the maximum elevation of the water table during the Performance Assessment (PA) period of compliance. A previous investigation to calculate the historical high water table beneath the SDF (Cook, 1983) was built upon to incorporate new data that has since become available to refine that estimate and develop a coverage that could be extended to the perennial streams adjacent to the SDF. This investigation incorporated the method used in the Cook, 1983 report to develop an estimate of the probable maximum water table for a group of wells that either existed at one time at or near the SDF or which currently exist. Estimates of the probable maximum water table at these wells were used to construct 2D contour lines depicting this surface beneath the SDF and extend them to the nearby hydrologic boundaries at the perennial streams adjacent to the SDF. Although certain measures were implemented to assure that the contour lines depict a surface above which the water table will not rise, the exact elevation of this surface cannot be known with complete certainty. It is therefore recommended that the construction of saltstone vaults incorporate a vertical buffer of at least 5-feet between the base of the vaults and the depicted probable maximum water table elevation. This should provide assurance that the water table under the wet extreme climatic condition will never rise to intercept the base of a vault.

  10. ULTRALUMINOUS STAR-FORMING GALAXIES AND EXTREMELY LUMINOUS WARM MOLECULAR HYDROGEN EMISSION AT z = 2.16 IN THE PKS 1138-26 RADIO GALAXY PROTOCLUSTER

    SciTech Connect (OSTI)

    Ogle, P.; Davies, J. E.; Helou, G. [IPAC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); Appleton, P. N. [NHSC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); Bertincourt, B. [Department of Astronomy, Columbia University, 550 West 120th Street, New York, New York 10027 (United States); Seymour, N., E-mail: ogle@ipac.caltech.edu [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)

    2012-05-20T23:59:59.000Z

    A deep Spitzer Infrared Spectrograph map of the PKS 1138-26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including H{alpha}-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of {approx}500-1100 M{sub Sun} yr{sup -1} are estimated from the 7.7 {mu}m PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of H{alpha} is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H{sub 2} 0-0 S(3)) = 1.4 Multiplication-Sign 10{sup 44} erg s{sup -1} (3.7 Multiplication-Sign 10{sup 10} L{sub Sun }), {approx}20 times more luminous than any previously known H{sub 2} emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 Multiplication-Sign 10{sup 6}-2 Multiplication-Sign 10{sup 9} M{sub Sun} of T > 300 K molecular gas, which may be heated by the PKS 1138-26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H{sub 2} at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected.

  11. THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. III. IMPLICATIONS FOR GALAXY CLUSTERS AND THE FORMATION OF DWARF GALAXIES

    SciTech Connect (OSTI)

    Pfrommer, Christoph [Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Chang, Philip; Broderick, Avery E., E-mail: christoph.pfrommer@h-its.org, E-mail: aeb@cita.utoronto.ca, E-mail: pchang@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

    2012-06-10T23:59:59.000Z

    A subset of blazars are powerful TeV emitters, dominating the extragalactic component of the very high energy gamma-ray universe (E {approx}> 100 GeV). These TeV gamma rays generate ultrarelativistic electron-positron pairs via pair production with the extragalactic background light. While it has generally been assumed that the kinetic energy of these pairs cascades to GeV gamma rays via inverse Compton scattering, we have argued in Broderick et al. (Paper I in this series) that plasma beam instabilities are capable of dissipating the pairs' energy locally on timescales short in comparison to the inverse Compton cooling time, heating the intergalactic medium (IGM) with a rate that is independent of density. This dramatically increases the entropy of the IGM after redshift z {approx} 2, with a number of important implications for structure formation: (1) this suggests a scenario for the origin of the cool core (CC)/non-cool core (NCC) bimodality in galaxy clusters and groups. Early-forming galaxy groups are unaffected because they can efficiently radiate the additional entropy, developing a CC. However, late-forming groups do not have sufficient time to cool before the entropy is gravitationally reprocessed through successive mergers-counteracting cooling and potentially raising the core entropy further. This may result in a population of X-ray dim groups/clusters, consistent with X-ray stacking analyses of optically selected samples. Hence, blazar heating works differently than feedback by active galactic nuclei, which we show can balance radiative cooling but is unable to transform CC into NCC clusters on the buoyancy timescale due to the weak coupling between the mechanical energy to the cluster gas. (2) We predict a suppression of the Sunyaev-Zel'dovich (SZ) power spectrum template on angular scales smaller than 5' due to the globally reduced central pressure of groups and clusters forming after z {approx} 1. This allows for a larger rms amplitude of the density power spectrum, {sigma}{sub 8}, and may reconcile SZ-inferred values with those by other cosmological probes even after allowing for a contribution due to patchy reionization. (3) Our redshift-dependent entropy floor increases the characteristic halo mass below which dwarf galaxies cannot form by a factor of approximately 10 (50) at mean density (in voids) over that found in models that include photoionization alone. This prevents the formation of late-forming dwarf galaxies (z {approx}< 2) with masses ranging from 10{sup 10} to 10{sup 11} M{sub Sun} for redshifts z {approx} 2 to 0, respectively. This may help resolve the 'missing satellite problem' in the Milky Way of the low observed abundances of dwarf satellites compared to cold dark matter simulations and may bring the observed early star formation histories into agreement with galaxy formation models. At the same time, it explains the 'void phenomenon' by suppressing the formation of galaxies within existing dwarf halos of masses <3 Multiplication-Sign 10{sup 10} M{sub Sun} with a maximum circular velocity <60 km s{sup -1} for z {approx}< 2, hence reconciling the number of dwarfs in low-density regions in simulations and the paucity of those in observations.

  12. The Spatial Clustering of ROSAT All-Sky Survey AGN: I. The cross-correlation function with SDSS Luminous Red Galaxies

    E-Print Network [OSTI]

    Krumpe, Mirko; Coil, Alison L

    2010-01-01T23:59:59.000Z

    We investigate the clustering properties of ~1550 broad-line AGNs at =0.25 detected in the ROSAT All-Sky Survey (RASS) through their measured cross-correlation function (CCF) with ~46000 Luminous Red Galaxies (LRGs) in the Sloan Digital Sky Survey. By measuring the cross-correlation of our AGN sample with a larger tracer set of LRGs, we both minimize shot noise errors due to the relatively small AGN sample size and avoid systematic errors due to the spatially-varying Galactic absorption that would affect direct measurements of the auto-correlation function (ACF) of the AGN sample. The measured ACF correlation length for the total RASS-AGN sample (=1.5 x 10^(44) erg/s) is r_0=4.3^{+0.4}_{-0.5} h^(-1) Mpc and the slope \\gamma=1.7^{+0.1}_{-0.1}. Splitting the sample into low and high L_X samples at L_(0.5-10 keV)=10^(44) erg/s, we detect an X-ray luminosity-dependence of the clustering amplitude at the ~2.5 \\sigma level. The low L_X sample has r_0=3.3^{+0.6}_{-0.8} h^(-1) Mpc (\\gamma=1.7^{+0.4}_{-0.3}), which is...

  13. Radio galaxies in the 2SLAQ Luminous Red Galaxy survey: II. The stellar populations of radio-loud and radio-quiet LRGs

    E-Print Network [OSTI]

    Helen M. Johnston; Elaine M. Sadler; Russell Cannon; Scott M. Croom; Nicholas P. Ross; Donald P. Schneider

    2007-11-21T23:59:59.000Z

    We present an analysis of the optical spectra of a volume-limited sample of 375 radio galaxies at redshift 0.4radio-quiet sources from the same survey, we also investigate the effect on the galaxy of the presence of an active nucleus. The composite spectra, binned by redshift and radio luminosity, all require two components to describe them, which we interpret as an old and a younger population. We found no evolution with redshift of the age of the younger population in radio galaxies, nor were they different from the radio-quiet comparison sample. Similarly, there is no correlation with radio power, with the exception that the most powerful radio sources (P(1.4) > 10^26 W/Hz) have younger stars and stronger emission lines than the less powerful sources. This suggests that we have located the threshold in radio power where strong emission lines "switch on", at radio powers of around 10^26 W/Hz. Except for the very powerful radio galaxies, the presence of a currently-active radio AGN does not appear to be correlated with any change in the observed stellar population of a luminous red galaxy at z~0.5.

  14. Two temperature viscous accretion flows around rotating black holes: Description of under-fed systems to ultra-luminous X-ray sources

    E-Print Network [OSTI]

    S. R. Rajesh; Banibrata Mukhopadhyay

    2009-11-02T23:59:59.000Z

    We discuss two temperature accretion disk flows around rotating black holes. As we know that to explain observed hard X-rays the choice of Keplerian angular momentum profile is not unique, we consider the sub-Keplerian regime of the disk. Without any strict knowledge of the magnetic field structure, we assume the cooling mechanism is dominated by bremsstrahlung process. We show that in a range of Shakura-Sunyaev viscosity parameter $0.2\\gsim\\alpha\\gsim0.0005$, flow behavior varies widely, particularly by means of the size of disk, efficiency of cooling and corresponding temperatures of ions and electrons. We also show that the disk around a rotating black hole is hotter compared to that around a Schwarzschild black hole, rendering a larger difference between ion and electron temperatures in the former case. With all the theoretical solutions in hand, finally we reproduce the observed luminosities ($L$) of two extreme cases -- the under-fed AGNs and quasars (e.g. Sgr $A^*$) with $L\\gsim 10^{33}$ erg/sec to ultra-luminous X-ray sources with $L\\sim 10^{41}$ erg/sec, at different combinations of mass accretion rate, ratio of specific heats, Shakura-Sunyaev viscosity parameter and Kerr parameter, and conclude that Sgr $A^*$ may be an intermediate spinning black hole.

  15. Discovery of a nearby twin of SN1987A's nebula around the luminous blue variable HD168625: Was Sk--69 202 an LBV?

    E-Print Network [OSTI]

    Nathan Smith

    2006-11-16T23:59:59.000Z

    Spitzer images of the luminous blue variable (LBV) candidate HD168625 reveal the existence of a bipolar nebula several times larger than its previously-known equatorial dust torus. The outer nebula of HD168625 has a full extent of about 80 arcsec or 0.85 pc, and one of the lobes has a well-defined polar ring. The nebula is a near twin of the triple-ring system around SN1987A. Because of these polar rings, and accounting for stellar/progenitor luminosity, HD168625 is an even closer twin of SN1987A than the B supergiant Sher 25 in NGC3603. HD168625's nebula was probably ejected during a giant LBV eruption and not during a red supergiant phase, so its similarity to the nebula around SN1987A may open new possibilities for the creation of SN1987A's rings. Namely, the hypothesis that Sk-69 202 suffered an LBV-like eruption would avert the complete surrender of single star models for its bipolar nebula by offering an alternative to an unlikely binary merger scenario. It also hints that LBVs are the likely progenitors of some type II supernovae, and that HD168625's nebula is a good example of a pre-explosion environment.

  16. Discovery of diffuse radio emission at the center of the most X-ray-luminous cluster RX J1347.5-1145

    E-Print Network [OSTI]

    Gitti, Myriam; Domainko, Wilfried; Feretti, Luigina; Schindler, Sabine

    2007-01-01T23:59:59.000Z

    We report on new VLA radio observations of the distant cluster RX J1347.5-1145, which is the most luminous in X-rays. We aim at investigating the possible presence of diffuse and extended radio emission in this very peculiar system which shows both a massive cooling flow and merging signatures. New low resolution (~18 arcsec) VLA radio observations of this cluster are combined with higher resolution (~2 arcsec) data available in the VLA archive. We discover the presence of a diffuse and extended (~500 kpc) radio source centered on the cluster, unrelated to the radio emission of the central AGN. The properties of the radio source, in particular a) its occurrence at the center of a massive cooling flow cluster, b) its total size comparable to that of the cooling region, c) its agreement with the observational trend between radio luminosity and cooling flow power, indicate that RX J1347.5-1145 hosts a radio mini-halo. We suggest that the radio emission of this mini-halo, which is the most distant object of its c...

  17. Discovery of diffuse radio emission at the center of the most X-ray-luminous cluster RX J1347.5-1145

    E-Print Network [OSTI]

    Myriam Gitti; Chiara Ferrari; Wilfried Domainko; Luigina Feretti; Sabine Schindler

    2007-06-20T23:59:59.000Z

    We report on new VLA radio observations of the distant cluster RX J1347.5-1145, which is the most luminous in X-rays. We aim at investigating the possible presence of diffuse and extended radio emission in this very peculiar system which shows both a massive cooling flow and merging signatures. New low resolution (~18 arcsec) VLA radio observations of this cluster are combined with higher resolution (~2 arcsec) data available in the VLA archive. We discover the presence of a diffuse and extended (~500 kpc) radio source centered on the cluster, unrelated to the radio emission of the central AGN. The properties of the radio source, in particular a) its occurrence at the center of a massive cooling flow cluster, b) its total size comparable to that of the cooling region, c) its agreement with the observational trend between radio luminosity and cooling flow power, indicate that RX J1347.5-1145 hosts a radio mini-halo. We suggest that the radio emission of this mini-halo, which is the most distant object of its class discovered up to now, is due to electron re-acceleration triggered by the central cooling flow. However, we also note that the morphology of the diffuse radio emission shows an elongation coincident with the position of a hot subclump detected in X-rays, thus suggesting that additional energy for the electron re-acceleration might be provided by the submerger event.

  18. HAWK-I imaging of the X-ray luminous galaxy cluster XMMU J2235.3-2557: The red sequence at z=1.39

    E-Print Network [OSTI]

    C. Lidman; P. Rosati; M. Tanaka; V. Strazzullo; R. Demarco; C. Mullis; N. Ageorges; M. Kissler-Patig; M. G. Petr-Gotzens; F. Selman

    2008-08-20T23:59:59.000Z

    We use HAWK-I, the recently-commissioned near-IR imager on Yepun (VLT-UT4), to obtain wide-field, high-resolution images of the X-ray luminous galaxy cluster XMMU J2235.3-2557 in the J and Ks bands, and we use these images to build a colour-magnitude diagram of cluster galaxies. Galaxies in the core of the cluster form a tight red sequence with a mean J-Ks colour of 1.9 (Vega system). The intrinsic scatter in the colour of galaxies that lie on the red sequence is similar to that measured for galaxies on the red sequence of the Coma cluster. The slope and location of the red sequence can be modelled by passively evolving the red sequence of the Coma cluster backwards in time. Using simple stellar population (SSP) models, we find that galaxies in the core of XMMU J2235.3-2557 are, even at z=1.39, already 3 Gyr old, corresponding to a formation redshift of z ~ 4. Outside the core, the intrinsic scatter and the fraction of galaxies actively forming stars increase substantially. Using SSP models, we find that most of these galaxies will join the red sequence within 1.5 Gyr. The contrast between galaxies in the cluster core and galaxies in the cluster outskirts indicates that the red sequence of XMMU J2235.3-2557 is being built from the dense cluster core outwards.

  19. A CO-rich merger shaping a powerful and hyper-luminous infrared radio galaxy at z=2: the Dragonfly Galaxy

    E-Print Network [OSTI]

    Emonts, B H C; Stroe, A; Pentericci, L; Villar-Martin, M; Norris, R P; Miley, G; De Breuck, C; van Moorsel, G A; Lehnert, M D; Carilli, C L; Rottgering, H J A; Seymour, N; Sadler, E M; Ekers, R D; Drouart, G; Feain, I; Colina, L; Stevens, J; Holt, J

    2015-01-01T23:59:59.000Z

    In the low-redshift Universe, the most powerful radio sources are often associated with gas-rich galaxy mergers or interactions. We here present evidence for an advanced, gas-rich (`wet') merger associated with a powerful radio galaxy at a redshift of z~2. This radio galaxy, MRC 0152-209, is the most infrared-luminous high-redshift radio galaxy known in the southern hemisphere. Using the Australia Telescope Compact Array, we obtained high-resolution CO(1-0) data of cold molecular gas, which we complement with HST/WFPC2 imaging and WHT long-slit spectroscopy. We find that, while roughly M(H2) ~ 2 x 10$^{10}$ M$_{\\odot}$ of molecular gas coincides with the central host galaxy, another M(H2) ~ 3 x 10$^{10}$ M$_{\\odot}$ is spread across a total extent of ~60 kpc. Most of this widespread CO(1-0) appears to follow prominent tidal features visible in the rest-frame near-UV HST/WFPC2 imaging. Ly$\\alpha$ emission shows an excess over HeII, but a deficiency over L(IR), which is likely the result of photo-ionisation by ...

  20. ALMA detection of a disc-dominated [C II] emission line at z=4.6 in the luminous QSO J1554+1937

    E-Print Network [OSTI]

    Kimball, Amy E; Lonsdale, Carol J; Macquart, J-P

    2015-01-01T23:59:59.000Z

    We present observations and analysis of an unusual [C II] emission line in the very luminous QSO SDSS J155426.16+193703.0 at z~4.6. The line is extremely broad (FWHM 735 km/s) and seems to have a flat-topped or double-peaked line profile. A velocity map of the line shows a gradient across the source that indicates large-scale rotation of star-forming gas. Together, the velocity map and line profile suggest the presence of a massive rotating disc with a dynamical mass M_dyn > 5x10^10 M_sun. Using the assumption of a rotating disc origin, we employ an empirical relation between galaxy disc circular velocity and bulge velocity dispersion (sigma) to estimate that sigma > 310 km/s, subject to a correction for the unknown disc inclination. This result implies that this source is consistent with the local M--sigma relation, or offset at most by an order of magnitude in black hole mass. In contrast, the assumption of a bulge origin for the [C II] emission line would lead to a conclusion that the black hole is nearly ...

  1. ALMA DETECTION OF THE VIBRATIONALLY EXCITED HCN J = 4-3 EMISSION LINE IN THE AGN-HOSTING LUMINOUS INFRARED GALAXY IRAS 20551–4250

    SciTech Connect (OSTI)

    Imanishi, Masatoshi [Subaru Telescope, 650 North A'ohoku Place, Hilo, Hawaii, 96720 (United States); Nakanishi, Kouichiro, E-mail: masa.imanishi@nao.ac.jp [Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura 763-0355, Santiago de Chile (Chile)

    2013-10-01T23:59:59.000Z

    We present results from our ALMA Cycle 0 observations, at the frequencies around the HCN, HCO{sup +}, and HNC J = 4-3 transition lines, of the luminous infrared galaxy IRAS 20551–4250 at z = 0.043, which is known to host an energetically important obscured active galactic nucleus (AGN). In addition to the targeted HCN, HCO{sup +}, and HNC J = 4-3 emission lines, two additional strong emission lines are seen, which we attribute to H{sub 2}S and CH{sub 3}CN(+CCH). The HCN-to-HCO{sup +} J = 4-3 flux ratio (?0.7) is higher than in the other starburst-dominated galaxy (?0.2) observed in our ALMA Cycle 0 program. We tentatively (?5?) detected the vibrationally excited (v {sub 2} = 1) HCN J = 4-3 (l = 1f) emission line, which is important for testing an infrared radiative pumping scenario for HCN. This is the second detection of this molecular transition in external galaxies. The most likely reason for this detection is not only the high flux of this emission line, but also the small molecular line widths observed in this galaxy, suggesting that vibrational excitation of HCN may be relatively common in AGN-hosting galaxies.

  2. Efficacy of Misuse Detection in Adhoc Networks Dhanant Subhadrabandhu, Saswati Sarkar, and Farooq Anjum

    E-Print Network [OSTI]

    Sarkar, Saswati

    1 Efficacy of Misuse Detection in Adhoc Networks Dhanant Subhadrabandhu, Saswati Sarkar, and Farooq. Subhadrabandhu and S. Sarkar are at the department of Electrical and Systems Engineering at the University

  3. Three dimensional winds: A maximum cross-correlation application to elastic lidar data

    SciTech Connect (OSTI)

    Buttler, W.T.

    1996-05-01T23:59:59.000Z

    Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar (light detection and ranging) data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three-dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain-following winds in the Rio Grande valley.

  4. On the minimum and maximum mass of neutron stars and the delayed collapse

    E-Print Network [OSTI]

    Strobel, K; Strobel, Klaus; Weigel, Manfred K.

    2001-01-01T23:59:59.000Z

    The minimum and maximum mass of protoneutron stars and neutron stars are investigated. The hot dense matter is described by relativistic (including hyperons) and non-relativistic equations of state. We show that the minimum mass ($\\sim$ 0.88 - 1.28 $M_{\\sun}$) of a neutron star is determined by the earliest stage of its evolution and is nearly unaffected by the presence of hyperons. The maximum mass of a neutron star is limited by the protoneutron star or hot neutron star stage. Further we find that the delayed collapse of a neutron star into a black hole during deleptonization is not only possible for equations of state with softening components, as for instance, hyperons, meson condensates etc., but also for neutron stars with a pure nucleonic-leptonic equation of state.

  5. On the minimum and maximum mass of neutron stars and the delayed collapse

    E-Print Network [OSTI]

    Klaus Strobel; Manfred K. Weigel

    2000-12-14T23:59:59.000Z

    The minimum and maximum mass of protoneutron stars and neutron stars are investigated. The hot dense matter is described by relativistic (including hyperons) and non-relativistic equations of state. We show that the minimum mass ($\\sim$ 0.88 - 1.28 $M_{\\sun}$) of a neutron star is determined by the earliest stage of its evolution and is nearly unaffected by the presence of hyperons. The maximum mass of a neutron star is limited by the protoneutron star or hot neutron star stage. Further we find that the delayed collapse of a neutron star into a black hole during deleptonization is not only possible for equations of state with softening components, as for instance, hyperons, meson condensates etc., but also for neutron stars with a pure nucleonic-leptonic equation of state.

  6. Evaluation of Maximum Radionuclide Groundwater Concentrations for Basement Fill Model. Zion Station Restoration Project

    SciTech Connect (OSTI)

    Sullivan, Terry [Brookhaven National Lab. (BNL), Upton, NY (United States). Biological, Environmental, and Climate Sciences Dept.

    2014-12-02T23:59:59.000Z

    ZionSolutions is in the process of decommissioning the Zion Nuclear Power Plant in order to establish a new water treatment plant. There is some residual radioactive particles from the plant which need to be brought down to levels so an individual who receives water from the new treatment plant does not receive a radioactive dose in excess of 25 mrem/y?¹. The objectives of this report are: (a) To present a simplified conceptual model for release from the buildings with residual subsurface structures that can be used to provide an upper bound on contaminant concentrations in the fill material; (b) Provide maximum water concentrations and the corresponding amount of mass sorbed to the solid fill material that could occur in each building for use in dose assessment calculations; (c) Estimate the maximum concentration in a well located outside of the fill material; and (d) Perform a sensitivity analysis of key parameters.

  7. Maximum-Entropy Meshfree Method for Compressible and Near-Incompressible Elasticity

    SciTech Connect (OSTI)

    Ortiz, A; Puso, M A; Sukumar, N

    2009-09-04T23:59:59.000Z

    Numerical integration errors and volumetric locking in the near-incompressible limit are two outstanding issues in Galerkin-based meshfree computations. In this paper, we present a modified Gaussian integration scheme on background cells for meshfree methods that alleviates errors in numerical integration and ensures patch test satisfaction to machine precision. Secondly, a locking-free small-strain elasticity formulation for meshfree methods is proposed, which draws on developments in assumed strain methods and nodal integration techniques. In this study, maximum-entropy basis functions are used; however, the generality of our approach permits the use of any meshfree approximation. Various benchmark problems in two-dimensional compressible and near-incompressible small strain elasticity are presented to demonstrate the accuracy and optimal convergence in the energy norm of the maximum-entropy meshfree formulation.

  8. How multiplicity determines entropy and the derivation of the maximum entropy principle for complex systems

    E-Print Network [OSTI]

    Hanel, Rudolf; Gell-Mann, Murray

    2014-01-01T23:59:59.000Z

    The maximum entropy principle (MEP) is a method for obtaining the most likely distribution functions of observables from statistical systems, by maximizing entropy under constraints. The MEP has found hundreds of applications in ergodic and Markovian systems in statistical mechanics, information theory, and statistics. For several decades there exists an ongoing controversy whether the notion of the maximum entropy principle can be extended in a meaningful way to non-extensive, non-ergodic, and complex statistical systems and processes. In this paper we start by reviewing how Boltzmann-Gibbs-Shannon entropy is related to multiplicities of independent random processes. We then show how the relaxation of independence naturally leads to the most general entropies that are compatible with the first three Shannon-Khinchin axioms, the (c,d)-entropies. We demonstrate that the MEP is a perfectly consistent concept for non-ergodic and complex statistical systems if their relative entropy can be factored into a general...

  9. Exact computation of the Maximum Entropy Potential of spiking neural networks models

    E-Print Network [OSTI]

    Cofre, Rodrigo

    2014-01-01T23:59:59.000Z

    Understanding how stimuli and synaptic connectivity in uence the statistics of spike patterns in neural networks is a central question in computational neuroscience. Maximum Entropy approach has been successfully used to characterize the statistical response of simultaneously recorded spiking neurons responding to stimuli. But, in spite of good performance in terms of prediction, the ?tting parameters do not explain the underlying mechanistic causes of the observed correlations. On the other hand, mathematical models of spiking neurons (neuro-mimetic models) provide a probabilistic mapping between stimulus, network architecture and spike patterns in terms of conditional proba- bilities. In this paper we build an exact analytical mapping between neuro-mimetic and Maximum Entropy models.

  10. Maximum-entropy principle for static and dynamic high-field transport in semiconductors

    SciTech Connect (OSTI)

    Trovato, M. [Dipartimento di Matematica, Universita di Catania, Viale A. Doria, 95125 Catania (Italy); Reggiani, L. [Dipartimento di Ingegneria dell' Innovazione e Nanotechnology National Laboratory of CNR-INFM, Universita di Lecce, Via Arnesano s/n, 73100 Lecce (Italy)

    2006-06-15T23:59:59.000Z

    Within the maximum entropy principle we present a general theory able to provide, in a dynamical context, the macroscopic relevant variables for carrier transport under electric fields of arbitrary strength. For the macroscopic variables the linearized maximum entropy approach is developed including full-band effects within a total energy scheme. Under spatially homogeneous conditions, we construct a closed set of hydrodynamic equations for the small-signal (dynamic) response of the macroscopic variables. The coupling between the driving field and the energy dissipation is analyzed quantitatively by using an arbitrary number of moments of the distribution function. The theoretical approach is applied to n-Si at 300 K and is validated by comparing numerical calculations with ensemble Monte Carlo simulations and with experimental data.

  11. Hydrodynamic equations for electrons in graphene obtained from the maximum entropy principle

    SciTech Connect (OSTI)

    Barletti, Luigi, E-mail: luigi.barletti@unifi.it [Dipartimento di Matematica e Informatica “Ulisse Dini”, Università degli Studi di Firenze, Viale Morgagni 67/A, 50134 Firenze (Italy)

    2014-08-15T23:59:59.000Z

    The maximum entropy principle is applied to the formal derivation of isothermal, Euler-like equations for semiclassical fermions (electrons and holes) in graphene. After proving general mathematical properties of the equations so obtained, their asymptotic form corresponding to significant physical regimes is investigated. In particular, the diffusive regime, the Maxwell-Boltzmann regime (high temperature), the collimation regime and the degenerate gas limit (vanishing temperature) are considered.

  12. REMARKS ON THE MAXIMUM ENTROPY METHOD APPLIED TO FINITE TEMPERATURE LATTICE QCD.

    SciTech Connect (OSTI)

    UMEDA, T.; MATSUFURU, H.

    2005-07-25T23:59:59.000Z

    We make remarks on the Maximum Entropy Method (MEM) for studies of the spectral function of hadronic correlators in finite temperature lattice QCD. We discuss the virtues and subtlety of MEM in the cases that one does not have enough number of data points such as at finite temperature. Taking these points into account, we suggest several tests which one should examine to keep the reliability for the results, and also apply them using mock and lattice QCD data.

  13. Towards the application of the Maximum Entropy Method to finite temperature Upsilon Spectroscopy

    E-Print Network [OSTI]

    M. Oevers; C. Davies; J. Shigemitsu

    2000-09-22T23:59:59.000Z

    According to the Narnhofer Thirring Theorem interacting systems at finite temperature cannot be described by particles with a sharp dispersion law. It is therefore mandatory to develop new methods to extract particle masses at finite temperature. The Maximum Entropy method offers a path to obtain the spectral function of a particle correlation function directly. We have implemented the method and tested it with zero temperature Upsilon correlation functions obtained from an NRQCD simulation. Results for different smearing functions are discussed.

  14. Maximum entropy deconvolution of resonant inelastic x-ray scattering spectra

    E-Print Network [OSTI]

    J. Laverock; A. R. H. Preston; D. Newby Jr; K. E. Smith; S. B. Dugdale

    2012-02-10T23:59:59.000Z

    Resonant inelastic x-ray scattering (RIXS) has become a powerful tool in the study of the electronic structure of condensed matter. Although the linewidths of many RIXS features are narrow, the experimental broadening can often hamper the identification of spectral features. Here, we show that the Maximum Entropy technique can successfully be applied in the deconvolution of RIXS spectra, improving the interpretation of the loss features without a severe increase in the noise ratio.

  15. Remarks on the Maximum Entropy Method applied to finite temperature lattice QCD

    E-Print Network [OSTI]

    Takashi Umeda; Hideo Matsufuru

    2005-10-05T23:59:59.000Z

    We make remarks on the Maximum Entropy Method (MEM) for studies of the spectral function of hadronic correlators in finite temperature lattice QCD. We discuss the virtues and subtlety of MEM in the cases that one does not have enough number of data points such as at finite temperature. Taking these points into account, we suggest several tests which one should examine to keep the reliability for the results, and also apply them using mock and lattice QCD data.

  16. Where and how long ago was water in the western North Atlantic ventilated? Maximum entropy inversions of bottle data from WOCE line A20

    E-Print Network [OSTI]

    Holzer, Mark; Primeau, Francois W; Smethie, William M; Khatiwala, Samar

    2010-01-01T23:59:59.000Z

    Gull (1991), Bayesian maximum entropy image reconstruction,F. Primeau (2006), A maximum entropy approach to water massSouth- ern Ocean? A maximum entropy approach to global water

  17. Maximum Neutral Buoyancy Depth of Juvenile Chinook Salmon: Implications for Survival during Hydroturbine Passage

    SciTech Connect (OSTI)

    Pflugrath, Brett D.; Brown, Richard S.; Carlson, Thomas J.

    2012-03-01T23:59:59.000Z

    This study investigated the maximum depth at which juvenile Chinook salmon Oncorhynchus tshawytscha can acclimate by attaining neutral buoyancy. Depth of neutral buoyancy is dependent upon the volume of gas within the swim bladder, which greatly influences the occurrence of injuries to fish passing through hydroturbines. We used two methods to obtain maximum swim bladder volumes that were transformed into depth estimations - the increased excess mass test (IEMT) and the swim bladder rupture test (SBRT). In the IEMT, weights were surgically added to the fishes exterior, requiring the fish to increase swim bladder volume in order to remain neutrally buoyant. SBRT entailed removing and artificially increasing swim bladder volume through decompression. From these tests, we estimate the maximum acclimation depth for juvenile Chinook salmon is a median of 6.7m (range = 4.6-11.6 m). These findings have important implications to survival estimates, studies using tags, hydropower operations, and survival of juvenile salmon that pass through large Kaplan turbines typical of those found within the Columbia and Snake River hydropower system.

  18. A Survey of z>5.8 Quasars in the Sloan Digital Sky Survey I: Discovery of Three New Quasars and the Spatial Density of Luminous Quasars at z~6

    E-Print Network [OSTI]

    Xiaohui Fan; Vijay K. Narayanan; Robert H. Lupton; Michael A. Strauss; Gillian R. Knapp; Robert H. Becker; Richard L. White; Laura Pentericci; S. K. Leggett; Zoltan Haiman; James E. Gunn; Zeljko Ivezic; Donald P. Schneider

    2001-09-03T23:59:59.000Z

    We present the results from a survey of i-dropout objects selected from ~1550 deg^2 of multicolor imaging data from the Sloan Digital Sky Survey, to search for luminous quasars at z>5.8. Objects with i*-z*>2.2 and z* 0.90. The ARC 3.5m spectrum of the z=6.28 quasar shows that over a range of 300 A immediately blueward of the Ly alpha emission, the average transmitted flux is only 0.003 +/-0.020 times that of the continuum level, consistent with zero flux, and suggesting a tentative detection of the complete Gunn-Peterson trough. The existence of strong metal lines suggests early chemical enrichment in the quasar enviornment. The three new objects, together with the previously published z=5.8 quasar form a complete color-selected flux-limited sample at z>5.8. We estimate that at $z=6$, the comoving density of luminous quasars at M_1450 luminous quasars discussed in the paper have central black hole masses of several times 10^9 M_sun by the Eddington argument. Their observed space density provides a sensitive test of models of quasar and galaxy formation at high redshift. (Abridged)

  19. Blind Joint Maximum Likelihood Channel Estimation and Data Detection for Single-Input Multiple-Output Systems

    E-Print Network [OSTI]

    Chen, Sheng

    Blind Joint Maximum Likelihood Channel Estimation and Data Detection for Single-Input Multiple of Southampton, Southampton SO17 1BJ, U.K. Abstract--A blind adaptive scheme is proposed for joint maximum. A simulation example is used to demon- strate the effectiveness of this joint ML optimization scheme for blind

  20. On Maximum Available Feedback and PID Control -1 IEEE SMC UK&RI Applied Cybernetics Dr Richard Mitchell 2005

    E-Print Network [OSTI]

    Mitchell, Richard

    On Maximum Available Feedback and PID Control - 1 IEEE SMC UK&RI Applied Cybernetics © Dr Richard Mitchell 2005 ON MAXIMUM AVAILABLE FEEDBACK AND PID CONTROL Dr Richard Mitchell, Cybernetics, University frequencies A recent IEEE SMC Paper describes a robust PID controller whose phase is flat at key frequencies

  1. Abstract--The many different techniques for maximum power point tracking of photovoltaic arrays are discussed. The

    E-Print Network [OSTI]

    Chapman, Patrick

    Abstract--The many different techniques for maximum power point tracking of photovoltaic arrays on implementation. This manuscript should serve as a convenient reference for future work in photovoltaic power generation. Index Terms--maximum power point tracking, MPPT, photovoltaic, PV. I. INTRODUCTION RACKING

  2. BONA FIDE, STRONG-VARIABLE GALACTIC LUMINOUS BLUE VARIABLE STARS ARE FAST ROTATORS: DETECTION OF A HIGH ROTATIONAL VELOCITY IN HR CARINAE

    SciTech Connect (OSTI)

    Groh, J. H. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Damineli, A.; Moises, A. P.; Teodoro, M. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, 05508-090, Sao Paulo, SP (Brazil); Hillier, D. J. [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Barba, R. [Departamento de fisica, Universidad de La Serena, Benavente 980, La Serena (Chile); Fernandez-Lajus, E.; Gamen, R. C.; Solivella, G., E-mail: jgroh@mpifr-bonn.mpg.d [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, and Instituto de Astrofisica de La Plata (CCT La Plata-CONICET), Paseo del Bosque S/N, B1900FWA, La Plata (Argentina)

    2009-11-01T23:59:59.000Z

    We report optical observations of the luminous blue variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to Si IV lambdalambda4088-4116. To match their observed line profiles from 2009 May, a high rotational velocity of v{sub rot} approx = 150 +- 20 km s{sup -1} is needed (assuming an inclination angle of 30 deg.), implying that HR Car rotates at approx =0.88 +- 0.2 of its critical velocity for breakup (v{sub crit}). Our results suggest that fast rotation is typical in all strong-variable, bona fide galactic LBVs, which present S-Dor-type variability. Strong-variable LBVs are located in a well-defined region of the HR diagram during visual minimum (the 'LBV minimum instability strip'). We suggest this region corresponds to where v{sub crit} is reached. To the left of this strip, a forbidden zone with v{sub rot}/v{sub crit}>1 is present, explaining why no LBVs are detected in this zone. Since dormant/ex LBVs like P Cygni and HD 168625 have low v{sub rot}, we propose that LBVs can be separated into two groups: fast-rotating, strong-variable stars showing S-Dor cycles (such as AG Car and HR Car) and slow-rotating stars with much less variability (such as P Cygni and HD 168625). We speculate that supernova (SN) progenitors which had S-Dor cycles before exploding (such as in SN 2001ig, SN 2003bg, and SN 2005gj) could have been fast rotators. We suggest that the potential difficulty of fast-rotating Galactic LBVs to lose angular momentum is additional evidence that such stars could explode during the LBV phase.

  3. Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX J1347.5-1145

    E-Print Network [OSTI]

    Maruša Brada?; Tim Schrabback; Thomas Erben; Michael McCourt; Evan Million; Adam Mantz; Steve Allen; Roger Blandford; Aleksi Halkola; Hendrik Hildebrandt; Marco Lombardi; Phil Marshall; Peter Schneider; Tommaso Treu; Jean-Paul Kneib

    2008-03-27T23:59:59.000Z

    The galaxy cluster RX J1347-1145 is one of the most X-ray luminous and most massive clusters known. Its extreme mass makes it a prime target for studying issues addressing cluster formation and cosmology. In this paper we present new high-resolution HST/ACS and Chandra X-ray data. The high resolution and sensitivity of ACS enabled us to detect and quantify several new multiply imaged sources, we now use a total of eight for the strong lensing analysis. Combining this information with shape measurements of weak lensing sources in the central regions of the cluster, we derive a high-resolution, absolutely-calibrated mass map. This map provides the best available quantification of the total mass of the central part of the cluster to date. We compare the reconstructed mass with that inferred from the new Chandra X-ray data, and conclude that both mass estimates agree extremely well in the observed region, namely within 400 / h_70 kpc of the cluster center. In addition we study the major baryonic components (gas and stars) and hence derive the dark matter distribution in the center of the cluster. We find that the dark matter and baryons are both centered on the BCG within the uncertainties (alignment is better than <10 kpc). We measure the corresponding 1-D profiles and find that dark matter distribution is consistent with both NFW and cored profiles, indicating that a more extended radial analysis is needed to pinpoint the concentration parameter, and hence the inner slope of the dark matter profile.

  4. A population of massive, luminous galaxies hosting heavily dust-obscured gamma-ray bursts: Implications for the use of GRBs as tracers of cosmic star formation

    SciTech Connect (OSTI)

    Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Cenko, S. B.; Bloom, J. S.; Filippenko, A. V.; Morgan, A. N. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Hjorth, J.; Krühler, T.; Fynbo, J. P. U.; Milvang-Jensen, B. [Dark Cosmology Centre, Niels Bohr Institute, Copenhagen (Denmark); Fruchter, A.; Kalirai, J. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavík (Iceland); Prochaska, J. X. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Silverman, J. M., E-mail: dperley@astro.caltech.edu [Department of Astronomy, University of Texas, Austin, TX 78712 (United States)

    2013-12-01T23:59:59.000Z

    We present observations and analysis of the host galaxies of 23 heavily dust-obscured gamma-ray bursts (GRBs) observed by the Swift satellite during the years 2005-2009, representing all GRBs with an unambiguous host-frame extinction of A{sub V} > 1 mag from this period. Deep observations with Keck, Gemini, Very Large Telescope, Hubble Space Telescope, and Spitzer successfully detect the host galaxies and establish spectroscopic or photometric redshifts for all 23 events, enabling us to provide measurements of the intrinsic host star formation rates, stellar masses, and mean extinctions. Compared to the hosts of unobscured GRBs at similar redshifts, we find that the hosts of dust-obscured GRBs are (on average) more massive by about an order of magnitude and also more rapidly star forming and dust obscured. While this demonstrates that GRBs populate all types of star-forming galaxies, including the most massive, luminous systems at z ? 2, at redshifts below 1.5 the overall GRB population continues to show a highly significant aversion to massive galaxies and a preference for low-mass systems relative to what would be expected given a purely star-formation-rate-selected galaxy sample. This supports the notion that the GRB rate is strongly dependent on metallicity, and may suggest that the most massive galaxies in the universe underwent a transition in their chemical properties ?9 Gyr ago. We also conclude that, based on the absence of unobscured GRBs in massive galaxies and the absence of obscured GRBs in low-mass galaxies, the dust distributions of the lowest-mass and the highest-mass galaxies are relatively homogeneous, while intermediate-mass galaxies (?10{sup 9} M {sub ?}) have diverse internal properties.

  5. Regarding the Line-of-Sight Baryonic Acoustic Feature in the Sloan Digital Sky Survey and Baryon Oscillation Spectroscopic Survey Luminous Red Galaxy Samples

    E-Print Network [OSTI]

    Eyal A. Kazin; Michael R. Blanton; Roman Scoccimarro; Cameron K. McBride; Andreas A. Berlind

    2010-04-13T23:59:59.000Z

    We analyze the line-of-sight baryonic acoustic feature in the two-point correlation function {\\xi} of the Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) sample (0.16 < z < 0.47). By defining a narrow line-of-sight region, rp < 5.5 Mpc/h, where rp is the transverse separation component, we measure a strong excess of clustering at ~ 110 Mpc/h, as previously reported in the literature. We also test these results in an alternative coordinate system, by defining the line-of-sight as {\\theta} < 3{\\deg}, where {\\theta} is the opening angle. This clustering excess appears much stronger than the feature in the better-measured monopole. A fiducial {\\Lambda}CDM non-linear model in redshift-space predicts a much weaker signature. We use realistic mock catalogs to model the expected signal and noise. We find that the line-of-sight measurements can be explained well by our mocks as well as by a featureless {\\xi} = 0. We conclude that there is no convincing evidence that the strong clustering measurement is the line-of-sight baryonic acoustic feature. We also evaluate how detectable such a signal would be in the upcoming Baryon Oscillation Spectroscopic Survey LRG volume (BOSS). Mock LRG catalogs (z < 0.6) suggest that: (i) the narrow line- of-sight cylinder and cone defined above probably will not reveal a detectable acoustic feature in BOSS; (ii) a clustering measurement as high as that in the current sample can be ruled out (or confirmed) at a high confidence level using a BOSS-sized data set; and (iii) an analysis with wider angular cuts, which provide better signal-to-noise ratios, can nevertheless be used to compare line-of-sight and transverse distances, and thereby constrain the expansion rate H(z) and diameter distance DA(z).

  6. Triggered or Self-Regulated Star Formation within Intermediate Redshift Luminous Infrared Galaxies (I). Morphologies and Spatially Resolved Spectral Energy Distributions

    E-Print Network [OSTI]

    J. Melbourne; M. Ammons; S. A. Wright; A. Metevier; E. Steinbring; C. Max; D. C. Koo; J. E. Larkin; M. Barczys

    2008-01-07T23:59:59.000Z

    We imaged a set of 15 intermediate redshift (z~0.8) luminous infrared galaxies (LIRGs) with the Keck Laser Guide Star (LGS) AO facility. These galaxies were selected from the GOODS-S field, allowing us to combine the high spatial resolution HST optical (B, V, i, and z-bands) images with our near-infrared (K'-band) images to study the LIRG morphologies and spatially resolved spectral energy distributions (SEDs). Two thirds of the LIRGs are disk galaxies, with only one third showing some evidence for interactions, minor, or major mergers. In contrast with local LIRG disks (which are primarily barred systems), only 10% of the LIRG disks in our sample contain a prominent bar. While the optical bands tend to show significant point-like substructure, indicating distributed star formation, the AO K-band images tend to be smooth. The SEDs of the LIRGs are consistent with distributed dusty star formation, as exhibited by optical to IR colors redder than allowed by old stellar populations alone. This effect is most pronounced in the galaxy cores, possibly indicating central star formation. We also observed a set of 11 intermediate redshift comparison galaxies, selected to be non-ellipticals with apparent K-band magnitudes comparable to the LIRGs. The "normal" (non-LIRG) systems tended to have lower optical luminosity, lower stellar mass, and more irregular morphology than the LIRGs. Half of the "normal" galaxies have SEDs consistent with intermediate aged stellar populations and minimal dust. The other half show evidence for some dusty star formation, usually concentrated in their cores. Our work suggests that the LIRG disk galaxies are similar to large disk systems today, undergoing self regulated star formation, only at 10 - 20 times higher rates. (Abridged)

  7. Free kick instead of cross-validation in maximum-likelihood refinement of macromolecular crystal structures

    SciTech Connect (OSTI)

    Pražnikar, Jure [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia); University of Primorska, (Slovenia); Turk, Dušan, E-mail: dusan.turk@ijs.si [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia); Center of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, (Slovenia)

    2014-12-01T23:59:59.000Z

    The maximum-likelihood free-kick target, which calculates model error estimates from the work set and a randomly displaced model, proved superior in the accuracy and consistency of refinement of crystal structures compared with the maximum-likelihood cross-validation target, which calculates error estimates from the test set and the unperturbed model. The refinement of a molecular model is a computational procedure by which the atomic model is fitted to the diffraction data. The commonly used target in the refinement of macromolecular structures is the maximum-likelihood (ML) function, which relies on the assessment of model errors. The current ML functions rely on cross-validation. They utilize phase-error estimates that are calculated from a small fraction of diffraction data, called the test set, that are not used to fit the model. An approach has been developed that uses the work set to calculate the phase-error estimates in the ML refinement from simulating the model errors via the random displacement of atomic coordinates. It is called ML free-kick refinement as it uses the ML formulation of the target function and is based on the idea of freeing the model from the model bias imposed by the chemical energy restraints used in refinement. This approach for the calculation of error estimates is superior to the cross-validation approach: it reduces the phase error and increases the accuracy of molecular models, is more robust, provides clearer maps and may use a smaller portion of data for the test set for the calculation of R{sub free} or may leave it out completely.

  8. A New Maximum-Likelihood Change Estimator for Two-Pass SAR Coherent Change Detection.

    SciTech Connect (OSTI)

    Wahl, Daniel E.; Yocky, David A.; Jakowatz, Charles V,

    2014-09-01T23:59:59.000Z

    In this paper, we derive a new optimal change metric to be used in synthetic aperture RADAR (SAR) coherent change detection (CCD). Previous CCD methods tend to produce false alarm states (showing change when there is none) in areas of the image that have a low clutter-to-noise power ratio (CNR). The new estimator does not suffer from this shortcoming. It is a surprisingly simple expression, easy to implement, and is optimal in the maximum-likelihood (ML) sense. The estimator produces very impressive results on the CCD collects that we have tested.

  9. Dynamics of multi-modes maximum entangled coherent state over amplitude damping channel

    E-Print Network [OSTI]

    A. El Allati; Y. Hassouni; N. Metwally

    2012-02-18T23:59:59.000Z

    The dynamics of maximum entangled coherent state travels through an amplitude damping channel is investigated. For small values of the transmissivity rate the travelling state is very fragile to this noise channel, where it suffers from the phase flip error with high probability. The entanglement decays smoothly for larger values of the transmissivity rate and speedily for smaller values of this rate. As the number of modes increases, the travelling state over this noise channel loses its entanglement hastily. The odd and even states vanish at the same value of the field intensity.

  10. On Weyl channels being covariant with respect to the maximum commutative group of unitaries

    E-Print Network [OSTI]

    G. G. Amosov

    2006-08-10T23:59:59.000Z

    We investigate the Weyl channels being covariant with respect to the maximum commutative group of unitary operators. This class includes the quantum depolarizing channel and the "two-Pauli" channel as well. Then, we show that our estimation of the output entropy for a tensor product of the phase damping channel and the identity channel based upon the decreasing property of the relative entropy allows to prove the additivity conjecture for the minimal output entropy for the quantum depolarizing channel in any prime dimesnsion and for the "two Pauli" channel in the qubit case.

  11. A reliable, fast and low cost maximum power point tracker for photovoltaic applications

    SciTech Connect (OSTI)

    Enrique, J.M.; Andujar, J.M.; Bohorquez, M.A. [Departamento de Ingenieria Electronica, de Sistemas Informaticos y Automatica, Universidad de Huelva (Spain)

    2010-01-15T23:59:59.000Z

    This work presents a new maximum power point tracker system for photovoltaic applications. The developed system is an analog version of the ''P and O-oriented'' algorithm. It maintains its main advantages: simplicity, reliability and easy practical implementation, and avoids its main disadvantages: inaccurateness and relatively slow response. Additionally, the developed system can be implemented in a practical way at a low cost, which means an added value. The system also shows an excellent behavior for very fast variables in incident radiation levels. (author)

  12. Study on Two Optimization Problems: Line Cover and Maximum Genus Embedding

    E-Print Network [OSTI]

    Cao, Cheng

    2012-07-16T23:59:59.000Z

    programming duality. We de ne a new problem called Non-collinear Packing Problem (NPP) as the following: De nition B.1. Non-collinear Packing Problem Given a set P of n points on the Euclidean plane R2, nd a maximum subset S P of non-collinear points, i....e. any three points are not collinear. Before proving the duality between NPP and LCP, we need to show how to formulate both problems to linear programming. To formulate the form of linear pro- gramming for instances of LCP and NNP, we use a few...

  13. Application of Maximum Entropy Method to Lattice Field Theory with a Topological Term

    E-Print Network [OSTI]

    M. Imachi; Y. Shinno; H. Yoneyama

    2003-09-22T23:59:59.000Z

    In Monte Carlo simulation, lattice field theory with a $\\theta$ term suffers from the sign problem. This problem can be circumvented by Fourier-transforming the topological charge distribution $P(Q)$. Although this strategy works well for small lattice volume, effect of errors of $P(Q)$ becomes serious with increasing volume and prevents one from studying the phase structure. This is called flattening. As an alternative approach, we apply the maximum entropy method (MEM) to the Gaussian $P(Q)$. It is found that the flattening could be much improved by use of the MEM.

  14. Conditional maximum-entropy method for selecting prior distributions in Bayesian statistics

    E-Print Network [OSTI]

    Abe, Sumiyoshi

    2014-01-01T23:59:59.000Z

    The conditional maximum-entropy method (abbreviated here as C-MaxEnt) is formulated for selecting prior probability distributions in Bayesian statistics for parameter estimation. This method is inspired by a statistical-mechanical approach to systems governed by dynamics with largely-separated time scales and is based on three key concepts: conjugate pairs of variables, dimensionless integration measures with coarse-graining factors and partial maximization of the joint entropy. The method enables one to calculate a prior purely from a likelihood in a simple way. It is shown in particular how it not only yields Jeffreys's rules but also reveals new structures hidden behind them.

  15. Charmonium spectra at finite temperature from QCD sum rules with the maximum entropy method

    E-Print Network [OSTI]

    Philipp Gubler; Kenji Morita; Makoto Oka

    2011-08-30T23:59:59.000Z

    Charmonia spectral functions at finite temperature are studied using QCD sum rules in combination with the maximum entropy method. This approach enables us to directly obtain the spectral function from the sum rules, without having to introduce any specific assumption about its functional form. As a result, it is found that while J/psi and eta_c manifest themselves as significant peaks in the spectral function below the deconfinement temperature T_c, they quickly dissolve into the continuum and almost completely disappear at temperatures between 1.0 T_c and 1.1 T_c.

  16. Spectral density analysis of time correlation functions in lattice QCD using the maximum entropy method

    E-Print Network [OSTI]

    H. Rudolf Fiebig

    2002-10-31T23:59:59.000Z

    We study various aspects of extracting spectral information from time correlation functions of lattice QCD by means of Bayesian inference with an entropic prior, the maximum entropy method (MEM). Correlator functions of a heavy-light meson-meson system serve as a repository for lattice data with diverse statistical quality. Attention is given to spectral mass density functions, inferred from the data, and their dependence on the parameters of the MEM. We propose to employ simulated annealing, or cooling, to solve the Bayesian inference problem, and discuss practical issues of the approach.

  17. Maximum Entropy and the Stress Distribution in Soft Disk Packings Above Jamming

    E-Print Network [OSTI]

    Yegang Wu; S. Teitel

    2014-10-17T23:59:59.000Z

    We show that the maximum entropy hypothesis can successfully explain the distribution of stresses on compact clusters of particles within disordered mechanically stable packings of soft, isotropically stressed, frictionless disks above the jamming transition. We show that, in our two dimensional case, it becomes necessary to consider not only the stress but also the Maxwell-Cremona force-tile area, as a constraining variable that determines the stress distribution. The importance of the force-tile area was suggested by earlier computations on an idealized force-network ensemble.

  18. Spectral Functions, Maximum Entropy Method and Unconventional Methods in Lattice Field Theory

    E-Print Network [OSTI]

    Chris Allton; Danielle Blythe; Jonathan Clowser

    2002-04-26T23:59:59.000Z

    We present two unconventional methods of extracting information from hadronic 2-point functions produced by Monte Carlo simulations. The first is an extension of earlier work by Leinweber which combines a QCD Sum Rule approach with lattice data. The second uses the Maximum Entropy Method to invert the 2-point data to obtain estimates of the spectral function. The first approach is applied to QCD data, and the second method is applied to the Nambu--Jona-Lasinio model in (2+1)D. Both methods promise to augment the current approach where physical quantities are extracted by fitting to pure exponentials.

  19. On Weyl channels being covariant with respect to the maximum commutative group of unitaries

    SciTech Connect (OSTI)

    Amosov, Grigori G. [Department of Higher Mathematics, Moscow Institute of Physics and Technology, Dolgoprudny 141700 (Russian Federation)

    2007-01-15T23:59:59.000Z

    We investigate the Weyl channels being covariant with respect to the maximum commutative group of unitary operators. This class includes the quantum depolarizing channel and the 'two-Pauli' channel as well. Then, we show that our estimation of the output entropy for a tensor product of the phase damping channel and the identity channel based upon the decreasing property of the relative entropy allows to prove the additivity conjecture for the minimal output entropy for the quantum depolarizing channel in any prime dimension and for the two-Pauli channel in the qubit case.

  20. Maximum entropy analysis of hadron spectral functions and excited states in quenched lattice QCD

    E-Print Network [OSTI]

    CP-PACS Collaboration; :; S. Aoki; R. Burkhalter; M. Fukugita; S. Hashimoto; N. Ishizuka; Y. Iwasaki; K. Kanaya; T. Kaneko; Y. Kuramashi; M. Okawa; Y. Taniguchi; A. Ukawa; T. Yamazaki; T. Yoshié

    2001-10-16T23:59:59.000Z

    Employing the maximum entropy method we extract the spectral functions from meson correlators at four lattice spacings in quenched QCD with the Wilson quark action. We confirm that the masses and decay constants, obtained from the position and the area of peaks, agree well with the results from the conventional exponential fit. For the first excited state, we obtain $m_{\\pi_1} = 660(590)$ MeV, $m_{\\rho_1} = 1540(570)$ MeV, and $f_{\\rho_1} = 0.085(36)$ in the continuum limit.

  1. The ACT{sup 2} project: Demonstration of maximum energy efficiency in real buildings

    SciTech Connect (OSTI)

    Crawley, D.B. [Pacific Northwest Lab., Richland, WA (United States); Krieg, B.L. [Pacific Gas and Electric Co., San Ramon, CA (United States)

    1991-11-01T23:59:59.000Z

    A large US utility recently began a project to determine whether the use of new energy-efficient end-use technologies and systems would economically achieve substantial energy savings (perhaps as high as 75% over current practice). Using a field-based demonstration approach, the Advanced Customer Technology Test (ACT{sup 2}) for Maximum Energy Efficiency is providing information on the maximum energy savings possible when integrated packages of new high-efficiency end-use technologies are incorporated into commercial and residential buildings and industrial and agricultural processes. This paper details the underlying rationale, approach, results to date, and future plans for ACT{sup 2}. The ultimate goal is energy efficiency (doing more with less energy) rather than energy conservation (freezing in the dark). In this paper, we first explain why a major United States utility is committed to pursuing demand-side management so aggressively. Next, we discuss the approach the utility chose for conducting the ACT{sup 2} project. We then review results obtained to date from the project`s pilot demonstration site. Last, we describe other related demonstration projects being proposed by the utility.

  2. The ACT sup 2 project: Demonstration of maximum energy efficiency in real buildings

    SciTech Connect (OSTI)

    Crawley, D.B. (Pacific Northwest Lab., Richland, WA (United States)); Krieg, B.L. (Pacific Gas and Electric Co., San Ramon, CA (United States))

    1991-11-01T23:59:59.000Z

    A large US utility recently began a project to determine whether the use of new energy-efficient end-use technologies and systems would economically achieve substantial energy savings (perhaps as high as 75% over current practice). Using a field-based demonstration approach, the Advanced Customer Technology Test (ACT{sup 2}) for Maximum Energy Efficiency is providing information on the maximum energy savings possible when integrated packages of new high-efficiency end-use technologies are incorporated into commercial and residential buildings and industrial and agricultural processes. This paper details the underlying rationale, approach, results to date, and future plans for ACT{sup 2}. The ultimate goal is energy efficiency (doing more with less energy) rather than energy conservation (freezing in the dark). In this paper, we first explain why a major United States utility is committed to pursuing demand-side management so aggressively. Next, we discuss the approach the utility chose for conducting the ACT{sup 2} project. We then review results obtained to date from the project's pilot demonstration site. Last, we describe other related demonstration projects being proposed by the utility.

  3. Variable Selection for Modeling the Absolute Magnitude at Maximum of Type Ia Supernovae

    E-Print Network [OSTI]

    Uemura, Makoto; Kawabata, S; Ikeda, Shiro; Maeda, Keiichi

    2015-01-01T23:59:59.000Z

    We discuss what is an appropriate set of explanatory variables in order to predict the absolute magnitude at the maximum of Type Ia supernovae. In order to have a good prediction, the error for future data, which is called the "generalization error," should be small. We use cross-validation in order to control the generalization error and LASSO-type estimator in order to choose the set of variables. This approach can be used even in the case that the number of samples is smaller than the number of candidate variables. We studied the Berkeley supernova database with our approach. Candidates of the explanatory variables include normalized spectral data, variables about lines, and previously proposed flux-ratios, as well as the color and light-curve widths. As a result, we confirmed the past understanding about Type Ia supernova: i) The absolute magnitude at maximum depends on the color and light-curve width. ii) The light-curve width depends on the strength of Si II. Recent studies have suggested to add more va...

  4. Quantifying extrinsic noise in gene expression using the maximum entropy framework

    E-Print Network [OSTI]

    Purushottam D. Dixit

    2013-04-04T23:59:59.000Z

    We present a maximum entropy framework to separate intrinsic and extrinsic contributions to noisy gene expression solely from the profile of expression. We express the experimentally accessible probability distribution of the copy number of the gene product (mRNA or protein) by accounting for possible variations in extrinsic factors. The distribution of extrinsic factors is estimated using the maximum entropy principle. Our results show that extrinsic factors qualitatively and quantitatively affect the probability distribution of the gene product. We work out, in detail, the transcription of mRNA from a constitutively expressed promoter in {\\it E. coli}. We suggest that the variation in extrinsic factors may account for the observed {\\it wider than Poisson} distribution of mRNA copy numbers. We successfully test our framework on a numerical simulation of a simple gene expression scheme that accounts for the variation in extrinsic factors. We also make falsifiable predictions, some of which are tested on previous experiments in {\\it E. coli} while others need verification. Application of the current framework to more complex situations is also discussed.

  5. Quantum maximum-entropy principle for closed quantum hydrodynamic transport within a Wigner function formalism

    SciTech Connect (OSTI)

    Trovato, M. [Dipartimento di Matematica, Universita di Catania, Viale A. Doria, I-95125 Catania (Italy); Reggiani, L. [Dipartimento di Ingegneria dell' Innovazione and CNISM, Universita del Salento, Via Arnesano s/n, I-73100 Lecce (Italy)

    2011-12-15T23:59:59.000Z

    By introducing a quantum entropy functional of the reduced density matrix, the principle of quantum maximum entropy is asserted as fundamental principle of quantum statistical mechanics. Accordingly, we develop a comprehensive theoretical formalism to construct rigorously a closed quantum hydrodynamic transport within a Wigner function approach. The theoretical formalism is formulated in both thermodynamic equilibrium and nonequilibrium conditions, and the quantum contributions are obtained by only assuming that the Lagrange multipliers can be expanded in powers of ({h_bar}/2{pi}){sup 2}. In particular, by using an arbitrary number of moments, we prove that (1) on a macroscopic scale all nonlocal effects, compatible with the uncertainty principle, are imputable to high-order spatial derivatives, both of the numerical density n and of the effective temperature T; (2) the results available from the literature in the framework of both a quantum Boltzmann gas and a degenerate quantum Fermi gas are recovered as a particular case; (3) the statistics for the quantum Fermi and Bose gases at different levels of degeneracy are explicitly incorporated; (4) a set of relevant applications admitting exact analytical equations are explicitly given and discussed; (5) the quantum maximum entropy principle keeps full validity in the classical limit, when ({h_bar}/2{pi}){yields}0.

  6. Analysis to determine the maximum dimensions of flexible apertures in sensored security netting products.

    SciTech Connect (OSTI)

    Murton, Mark; Bouchier, Francis A.; vanDongen, Dale T.; Mack, Thomas Kimball; Cutler, Robert Paul; Ross, Michael P.

    2013-08-01T23:59:59.000Z

    Although technological advances provide new capabilities to increase the robustness of security systems, they also potentially introduce new vulnerabilities. New capability sometimes requires new performance requirements. This paper outlines an approach to establishing a key performance requirement for an emerging intrusion detection sensor: the sensored net. Throughout the security industry, the commonly adopted standard for maximum opening size through barriers is a requirement based on square inches-typically 96 square inches. Unlike standard rigid opening, the dimensions of a flexible aperture are not fixed, but variable and conformable. It is demonstrably simple for a human intruder to move through a 96-square-inch opening that is conformable to the human body. The longstanding 96-square-inch requirement itself, though firmly embedded in policy and best practice, lacks a documented empirical basis. This analysis concluded that the traditional 96-square-inch standard for openings is insufficient for flexible openings that are conformable to the human body. Instead, a circumference standard is recommended for these newer types of sensored barriers. The recommended maximum circumference for a flexible opening should be no more than 26 inches, as measured on the inside of the netting material.

  7. Bounds and phase diagram of efficiency at maximum power for tight-coupling molecular motors

    E-Print Network [OSTI]

    Z. C. Tu

    2013-02-08T23:59:59.000Z

    The efficiency at maximum power (EMP) for tight-coupling molecular motors is investigated within the framework of irreversible thermodynamics. It is found that the EMP depends merely on the constitutive relation between the thermodynamic current and force. The motors are classified into four generic types (linear, superlinear, sublinear, and mixed types) according to the characteristics of the constitutive relation, and then the corresponding ranges of the EMP for these four types of molecular motors are obtained. The exact bounds of the EMP are derived and expressed as the explicit functions of the free energy released by the fuel in each motor step. A phase diagram is constructed which clearly shows how the region where the parameters (the load distribution factor and the free energy released by the fuel in each motor step) are located can determine whether the value of the EMP is larger or smaller than 1/2. This phase diagram reveals that motors using ATP as fuel under physiological conditions can work at maximum power with higher efficiency ($>1/2$) for a small load distribution factor ($<0.1$).

  8. Comments on (super)luminality

    E-Print Network [OSTI]

    Claudia de Rham; Gregory Gabadadze; Andrew J. Tolley

    2011-07-22T23:59:59.000Z

    Recently, in an interesting work arXiv:1106.3972 a solution of the equations of motion of massive gravity was discussed, and it was shown that one of the fluctuations on that solution is superluminal. It was also stated that this rules out massive gravity. Here we find that the solution itself is rather unphysical. For this we show that there is another mode on the same background which grows and overcomes the background in an arbitrarily short period of time, that can be excited by a negligible cost in energy. This solution is triggered by the parameter governing the superluminality. Furthermore, we also show that the solution, if viewed as a perfect fluid, has no rest frame, or that the Lorentz transformation that is needed to boost to the rest frame is superluminal itself. The stress-tensor of this fluid has complex eigenvalues, and could not be obtained from any physically sensible matter. Moreover, for the same setup we find another background solution, fluctuations of which are all stable and subluminal. Based on these results, we conclude that the superluminality found in arXiv:1106.3972 is an artifact of using an inappropriate background, nevertheless, this solution represents an instructive example for understanding massive gravity. For instance, on this background the Boulware-Deser ghost is absent, even though this may naively appear not to be the case.

  9. Luminate LLC | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOf KilaueaInformation Other4Q07) WindLow VoltageGroup

  10. Combustion Process in a Spark Ignition Engine: Analysis of Cyclic Maximum Pressure and Peak Pressure Angle

    E-Print Network [OSTI]

    G. Litak; T. Kaminski; J. Czarnigowski; A. K. Sen; M. Wendeker

    2006-11-29T23:59:59.000Z

    In this paper we analyze the cycle-to-cycle variations of maximum pressure $p_{max}$ and peak pressure angle $\\alpha_{pmax}$ in a four-cylinder spark ignition engine. We examine the experimental time series of $p_{max}$ and $\\alpha_{pmax}$ for three different spark advance angles. Using standard statistical techniques such as return maps and histograms we show that depending on the spark advance angle, there are significant differences in the fluctuations of $p_{max}$ and $\\alpha_{pmax}$. We also calculate the multiscale entropy of the various time series to estimate the effect of randomness in these fluctuations. Finally, we explain how the information on both $p_{max}$ and $\\alpha_{pmax}$ can be used to develop optimal strategies for controlling the combustion process and improving engine performance.

  11. Predicting Whole Forest Structure, Primary Productivity, and Biomass Density From Maximum Tree Size and Resource Limitations

    E-Print Network [OSTI]

    Kempes, Christopher P; Dooris, William; West, Geoffrey B

    2015-01-01T23:59:59.000Z

    In the face of uncertain biological response to climate change and the many critiques concerning model complexity it is increasingly important to develop predictive mechanistic frameworks that capture the dominant features of ecological communities and their dependencies on environmental factors. This is particularly important for critical global processes such as biomass changes, carbon export, and biogenic climate feedback. Past efforts have successfully understood a broad spectrum of plant and community traits across a range of biological diversity and body size, including tree size distributions and maximum tree height, from mechanical, hydrodynamic, and resource constraints. Recently it was shown that global scaling relationships for net primary productivity are correlated with local meteorology and the overall biomass density within a forest. Along with previous efforts, this highlights the connection between widely observed allometric relationships and predictive ecology. An emerging goal of ecological...

  12. Role of ocean-atmosphere interactions in tropical cooling during the last glacial maximum

    SciTech Connect (OSTI)

    Bush, A.B.G. [Univ. of Alberta, Edmonton (Canada)] [Univ. of Alberta, Edmonton (Canada); Philander, S.G.H. [Princeton Univ., NJ (United States)] [Princeton Univ., NJ (United States)

    1998-02-27T23:59:59.000Z

    A simulation with a coupled atmosphere-ocean general circulation model configured for the Last Glacial Maximum delivered a tropical climate that is much cooler than that produced by atmosphere-only models. The main reason is a decrease in tropical sea surface temperatures, up to 6{degree}C in the western tropical Pacific, which occurs because of two processes. The trade winds induce equatorial upwelling and zonal advection of cold water that further intensify the trade winds, and an exchange of water occurs between the tropical and extratropical Pacific in which the poleward surface flow is balanced by equatorward flow of cold water in the thermocline. Simulated tropical temperature depressions are of the same magnitude as those that have been proposed from recent proxy data. 25 refs., 4 figs.

  13. Detailed analysis of an endoreversible fuel cell : Maximum power and optimal operating temperature determination

    E-Print Network [OSTI]

    A. Vaudrey; P. Baucour; F. Lanzetta; R. Glises

    2010-08-30T23:59:59.000Z

    Producing useful electrical work in consuming chemical energy, the fuel cell have to reject heat to its surrounding. However, as it occurs for any other type of engine, this thermal energy cannot be exchanged in an isothermal way in finite time through finite areas. As it was already done for various types of systems, we study the fuel cell within the finite time thermodynamics framework and define an endoreversible fuel cell. Considering different types of heat transfer laws, we obtain an optimal value of the operating temperature, corresponding to a maximum produced power. This analysis is a first step of a thermodynamical approach of design of thermal management devices, taking into account performances of the whole system.

  14. Detailed analysis of an endoreversible fuel cell : Maximum power and optimal operating temperature determination

    E-Print Network [OSTI]

    Vaudrey, A; Lanzetta, F; Glises, R

    2009-01-01T23:59:59.000Z

    Producing useful electrical work in consuming chemical energy, the fuel cell have to reject heat to its surrounding. However, as it occurs for any other type of engine, this thermal energy cannot be exchanged in an isothermal way in finite time through finite areas. As it was already done for various types of systems, we study the fuel cell within the finite time thermodynamics framework and define an endoreversible fuel cell. Considering different types of heat transfer laws, we obtain an optimal value of the operating temperature, corresponding to a maximum produced power. This analysis is a first step of a thermodynamical approach of design of thermal management devices, taking into account performances of the whole system.

  15. From Physics to Economics: An Econometric Example Using Maximum Relative Entropy

    E-Print Network [OSTI]

    Giffin, Adom

    2009-01-01T23:59:59.000Z

    Econophysics, is based on the premise that some ideas and methods from physics can be applied to economic situations. We intend to show in this paper how a physics concept such as entropy can be applied to an economic problem. In so doing, we demonstrate how information in the form of observable data and moment constraints are introduced into the method of Maximum relative Entropy (MrE). A general example of updating with data and moments is shown. Two specific econometric examples are solved in detail which can then be used as templates for real world problems. A numerical example is compared to a large deviation solution which illustrates some of the advantages of the MrE method.

  16. Bayesian and maximum entropy methods for fusion diagnostic measurements with compact neutron spectrometers

    SciTech Connect (OSTI)

    Reginatto, Marcel; Zimbal, Andreas [Physikalisch-Technische Bundesanstalt, 38116 Braunschweig (Germany)

    2008-02-15T23:59:59.000Z

    In applications of neutron spectrometry to fusion diagnostics, it is advantageous to use methods of data analysis which can extract information from the spectrum that is directly related to the parameters of interest that describe the plasma. We present here methods of data analysis which were developed with this goal in mind, and which were applied to spectrometric measurements made with an organic liquid scintillation detector (type NE213). In our approach, we combine Bayesian parameter estimation methods and unfolding methods based on the maximum entropy principle. This two-step method allows us to optimize the analysis of the data depending on the type of information that we want to extract from the measurements. To illustrate these methods, we analyze neutron measurements made at the PTB accelerator under controlled conditions, using accelerator-produced neutron beams. Although the methods have been chosen with a specific application in mind, they are general enough to be useful for many other types of measurements.

  17. Maximum Achievable Control Technology for New Industrial Boilers (released in AEO2005)

    Reports and Publications (EIA)

    2005-01-01T23:59:59.000Z

    As part of Clean Air Act 90 (CAAA90, the EPA on February 26, 2004, issued a final rulethe National Emission Standards for Hazardous Air Pollutants (NESHAP) to reduce emissions of hazardous air pollutants (HAPs) from industrial, commercial, and institutional boilers and process heaters. The rule requires industrial boilers and process heaters to meet limits on HAP emissions to comply with a Maximum Achievable Control Technology (MACT) floor level of control that is the minimum level such sources must meet to comply with the rule. The major HAPs to be reduced are hydrochloric acid, hydrofluoric acid, arsenic, beryllium, cadmium, and nickel. The EPA predicts that the boiler MACT rule will reduce those HAP emissions from existing sources by about 59,000 tons per year in 2005.

  18. Online Robot Dead Reckoning Localization Using Maximum Relative Entropy Optimization With Model Constraints

    SciTech Connect (OSTI)

    Urniezius, Renaldas [Kaunas University of Technology, Kaunas (Lithuania)

    2011-03-14T23:59:59.000Z

    The principle of Maximum relative Entropy optimization was analyzed for dead reckoning localization of a rigid body when observation data of two attached accelerometers was collected. Model constraints were derived from the relationships between the sensors. The experiment's results confirmed that accelerometers each axis' noise can be successfully filtered utilizing dependency between channels and the dependency between time series data. Dependency between channels was used for a priori calculation, and a posteriori distribution was derived utilizing dependency between time series data. There was revisited data of autocalibration experiment by removing the initial assumption that instantaneous rotation axis of a rigid body was known. Performance results confirmed that such an approach could be used for online dead reckoning localization.

  19. Azimuthal Anisotropy in Heavy Ion Collisions from the Maximum Entropy Method

    E-Print Network [OSTI]

    Pirner, Hans J

    2014-01-01T23:59:59.000Z

    We investigate the azimuthal anisotropy v2 of particle production in nucleus-nucleus collisions in the maximum entropy approach. This necessitates two new parameters delta and lambda2. The parameter delta describes the deformation of transverse configuration space and is related to the anisotropy of the overlap zone of the two nuclei. The parameter lambda2 defines the anisotropy of the particle distribution in momentum space. Assuming deformed flux tubes at the early stage of the collision we relate the momentum to the space asymmetry i.e. lambda2 to delta with the uncertainty relation. We compute the anisotropy v2 as a function of centrality, transverse momentum and rapidity using gluon-hadron duality. The general features of LHC data are reproduced.

  20. Source Function Determined from HBT Correlations by the Maximum Entropy Principle

    E-Print Network [OSTI]

    Wu Yuanfang; Ulrich Heinz

    1996-07-18T23:59:59.000Z

    We study the reconstruction of the source function in space-time directly from the measured HBT correlation function using the Maximum Entropy Principle. We find that the problem is ill-defined without at least one additional theoretical constraint as input. Using the requirement of a finite source lifetime for the latter we find a new Gaussian parametrization of the source function directly in terms of the measured HBT radius parameters and its lifetime, where the latter is a free parameter which is not directly measurable by HBT. We discuss the implications of our results for the remaining freedom in building source models consistent with a given set of measured HBT radius parameters.

  1. Spectral Analysis of Excited Nucleons in Lattice QCD with Maximum Entropy Method

    E-Print Network [OSTI]

    Kiyoshi Sasaki; Shoichi Sasaki; Tetsuo Hatsuda

    2005-07-12T23:59:59.000Z

    We study the mass spectra of excited baryons with the use of the lattice QCD simulations. We focus our attention on the problem of the level ordering between the positive-parity excited state N'(1440) (the Roper resonance) and the negative-parity excited state N^*(1535). Nearly perfect parity projection is accomplished by combining the quark propagators with periodic and anti-periodic boundary conditions in the temporal direction. Then we extract the spectral functions from the lattice data by utilizing the maximum entropy method. We observe that the masses of the N' and N^* states are close for wide range of the quark masses (M_pi=0.61-1.22 GeV), which is in contrast to the phenomenological prediction of the quark models. The role of the Wilson doublers in the baryonic spectral functions is also studied.

  2. A maximum-entropy approach to the adiabatic freezing of a supercooled liquid

    E-Print Network [OSTI]

    Santi Prestipino

    2013-04-29T23:59:59.000Z

    I employ the van der Waals theory of Baus and coworkers to analyze the fast, adiabatic decay of a supercooled liquid in a closed vessel with which the solidification process usually starts. By imposing a further constraint on either the system volume or pressure, I use the maximum-entropy method to quantify the fraction of liquid that is transformed into solid as a function of undercooling and of the amount of a foreign gas that could possibly be also present in the test tube. Upon looking at the implications of thermal and mechanical insulation for the energy cost of forming a solid droplet within the liquid, I identify one situation where the onset of solidification inevitably occurs near the wall in contact with the bath.

  3. Lyapunov exponent and natural invariant density determination of chaotic maps: An iterative maximum entropy ansatz

    E-Print Network [OSTI]

    Parthapratim Biswas; H. Shimoyama; L. R. Mead

    2009-10-23T23:59:59.000Z

    We apply the maximum entropy principle to construct the natural invariant density and Lyapunov exponent of one-dimensional chaotic maps. Using a novel function reconstruction technique that is based on the solution of Hausdorff moment problem via maximizing Shannon entropy, we estimate the invariant density and the Lyapunov exponent of nonlinear maps in one-dimension from a knowledge of finite number of moments. The accuracy and the stability of the algorithm are illustrated by comparing our results to a number of nonlinear maps for which the exact analytical results are available. Furthermore, we also consider a very complex example for which no exact analytical result for invariant density is available. A comparison of our results to those available in the literature is also discussed.

  4. Spectral function and excited states in lattice QCD with maximum entropy method

    E-Print Network [OSTI]

    CP-PACS Collaboration; :; T. Yamazaki; S. Aoki; R. Burkhalter; M. Fukugita; S. Hashimoto; N. Ishizuka; Y. Iwasaki; K. Kanaya; T. Kaneko; Y. Kuramashi; M. Okawa; Y. Taniguchi; A. Ukawa; T. Yoshié

    2001-05-29T23:59:59.000Z

    We apply the maximum entropy method to extract the spectral functions for pseudoscalar and vector mesons from hadron correlators previously calculated at four different lattice spacings in quenched QCD with the Wilson quark action. We determine masses and decay constants for the ground and excited states of the pseudoscalar and vector channels from position and area of peaks in the spectral functions. We obtain the results, $m_{\\pi_1} = 660(590)$ MeV and $m_{\\rho_1} = 1540(570)$ MeV for the masses of the first excited state masses, in the continuum limit of quenched QCD. We also find unphysical states which have infinite mass in the continuum limit, and argue that they are bound states of two doublers of the Wilson quark action. If the interpretation is correct, this is the first time that the state of doublers is identified in lattice QCD numerical simulations.

  5. Application of the Maximum Entropy Method to the (2+1)d Four-Fermion Model

    E-Print Network [OSTI]

    C. R. Allton; J. E. Clowser; S. J. Hands; J. B. Kogut; C. G. Strouthos

    2002-08-19T23:59:59.000Z

    We investigate spectral functions extracted using the Maximum Entropy Method from correlators measured in lattice simulations of the (2+1)-dimensional four-fermion model. This model is particularly interesting because it has both a chirally broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are only resonances. In the broken phase we study the elementary fermion, pion, sigma and massive pseudoscalar meson; our results confirm the Goldstone nature of the pi and permit an estimate of the meson binding energy. We have, however, seen no signal of sigma -> pi pi decay as the chiral limit is approached. In the symmetric phase we observe a resonance of non-zero width in qualitative agreement with analytic expectations; in addition the ultra-violet behaviour of the spectral functions is consistent with the large non-perturbative anomalous dimension for fermion composite operators expected in this model.

  6. Azimuthal Anisotropy in Heavy Ion Collisions from the Maximum Entropy Method

    E-Print Network [OSTI]

    Hans J. Pirner

    2014-05-09T23:59:59.000Z

    We investigate the azimuthal anisotropy v2 of particle production in nucleus-nucleus collisions in the maximum entropy approach. This necessitates two new parameters delta and lambda2. The parameter delta describes the deformation of transverse configuration space and is related to the anisotropy of the overlap zone of the two nuclei. The parameter lambda2 defines the anisotropy of the particle distribution in momentum space. Assuming deformed flux tubes at the early stage of the collision we relate the momentum to the space asymmetry i.e. lambda2 to delta with the uncertainty relation. We compute the anisotropy v2 as a function of centrality, transverse momentum and rapidity using gluon-hadron duality. The general features of LHC data are reproduced.

  7. CP$^{N-1}$ model with the theta term and maximum entropy method

    E-Print Network [OSTI]

    Masahiro Imachi; Yasuhiko Shinno; Hiroshi Yoneyama

    2004-09-25T23:59:59.000Z

    A $\\theta$ term in lattice field theory causes the sign problem in Monte Carlo simulations. This problem can be circumvented by Fourier-transforming the topological charge distribution $P(Q)$. This strategy, however, has a limitation, because errors of $P(Q)$ prevent one from calculating the partition function ${\\cal Z}(\\theta)$ properly for large volumes. This is called flattening. As an alternative approach to the Fourier method, we utilize the maximum entropy method (MEM) to calculate ${\\cal Z}(\\theta)$. We apply the MEM to Monte Carlo data of the CP$^3$ model. It is found that in the non-flattening case, the result of the MEM agrees with that of the Fourier transform, while in the flattening case, the MEM gives smooth ${\\cal Z}(\\theta)$.

  8. SN 2005ip: A luminous type IIn supernova emerging from a dense circumstellar medium as revealed by X-ray observations

    SciTech Connect (OSTI)

    Katsuda, Satoru [RIKEN (The Institute of Physical and Chemical Research) Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Nozawa, Takaya [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Pooley, David [Department of Physics, Sam Houston State University, Huntsville, TX 77341-2267 (United States); Immler, Stefan [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 2077 (United States)

    2014-01-10T23:59:59.000Z

    We report on the X-ray spectral evolution of the nearby Type IIn supernova (SN) 2005ip based on Chandra and Swift observations covering ?1-6 yr after explosion. X-ray spectra in all epochs are well fitted by a thermal emission model with kT ? 7 keV. The somewhat high temperature suggests that the X-ray emission mainly arises from the circumstellar medium (CSM) heated by the forward shock. We find that the spectra taken two to three years after the explosion are heavily absorbed (N {sub H} ? 5 × 10{sup 22} cm{sup –2}), but the absorption gradually decreases to the level of the Galactic absorption (N {sub H} ? 4 × 10{sup 20} cm{sup –2}) at the final epoch. This indicates that the SN went off in a dense CSM and that the forward shock has overtaken it. The intrinsic X-ray luminosity stays constant until the final epoch, when it drops by a factor of ?2. The intrinsic 0.2-10 keV luminosity during the plateau phase is measured to be ?1.5 × 10{sup 41} erg s{sup –1}, ranking SN 2005ip as one of the brightest X-ray SNe. Based on the column density, we derive a lower limit of a mass-loss rate to be M-dot ?1.5×10{sup ?2} (V{sub w} /100 km s{sup –1}) M {sub ?} yr{sup –1}, which roughly agrees with that inferred from the X-ray luminosity, M-dot ?2×10{sup ?2} (V{sub w} /100 km s{sup –1}) M {sub ?} yr{sup –1}, where V{sub w} is the circumstellar wind speed. Such a high mass-loss rate suggests that the progenitor star had eruptive mass ejections similar to a luminous blue variable star. The total mass ejected in the eruptive period is estimated to be ?15 M {sub ?}, indicating that the progenitor mass is ? 25 M {sub ?}.

  9. Is the friction angle the maximum slope of a free surface of a non cohesive material?

    E-Print Network [OSTI]

    A. Modaressi; P. Evesque

    2005-07-13T23:59:59.000Z

    Starting from a symmetric triangular pile with a horizontal basis and rotating the basis in the vertical plane, we have determined the evolution of the stress distribution as a function of the basis inclination using Finite Elements method with an elastic-perfectly plastic constitutive model, defined by its friction angle, without cohesion. It is found that when the yield function is the Drucker-Prager one, stress distribution satisfying equilibrium can be found even when one of the free-surface slopes is larger than the friction angle. This means that piles with a slope larger than the friction angle can be (at least) marginally stable and that slope rotation is not always a destabilising perturbation direction. On the contrary, it is found that the slope cannot overpass the friction angle when a Mohr-Coulomb yield function is used. Theoretical explanation of these facts is given which enlightens the role plaid by the intermediate principal stress in both cases of the Mohr-Coulomb criterion and of the Drucker-Prager one. It is then argued that the Mohr-Coulomb criterion assumes a spontaneous symmetry breaking, as soon as the two smallest principal stresses are different ; this is not physical most likely; so this criterion shall be replaced by a Drucker-Prager criterion in the vicinity of the equality, which leads to the previous anomalous behaviour ; so these numerical computations enlighten the avalanche process: they show that no dynamical angle larger than the static one is needed to understand avalanching. It is in agreement with previous experimental results. Furthermore, these results show that the maximum angle of repose can be modified using cyclic rotations; we propose a procedure that allows to achieve a maximum angle of repose to be equal to the friction angle .

  10. Thirty-Year Solid Waste Generation Maximum and Minimum Forecast for SRS

    SciTech Connect (OSTI)

    Thomas, L.C.

    1994-10-01T23:59:59.000Z

    This report is the third phase (Phase III) of the Thirty-Year Solid Waste Generation Forecast for Facilities at the Savannah River Site (SRS). Phase I of the forecast, Thirty-Year Solid Waste Generation Forecast for Facilities at SRS, forecasts the yearly quantities of low-level waste (LLW), hazardous waste, mixed waste, and transuranic (TRU) wastes generated over the next 30 years by operations, decontamination and decommissioning and environmental restoration (ER) activities at the Savannah River Site. The Phase II report, Thirty-Year Solid Waste Generation Forecast by Treatability Group (U), provides a 30-year forecast by waste treatability group for operations, decontamination and decommissioning, and ER activities. In addition, a 30-year forecast by waste stream has been provided for operations in Appendix A of the Phase II report. The solid wastes stored or generated at SRS must be treated and disposed of in accordance with federal, state, and local laws and regulations. To evaluate, select, and justify the use of promising treatment technologies and to evaluate the potential impact to the environment, the generic waste categories described in the Phase I report were divided into smaller classifications with similar physical, chemical, and radiological characteristics. These smaller classifications, defined within the Phase II report as treatability groups, can then be used in the Waste Management Environmental Impact Statement process to evaluate treatment options. The waste generation forecasts in the Phase II report includes existing waste inventories. Existing waste inventories, which include waste streams from continuing operations and stored wastes from discontinued operations, were not included in the Phase I report. Maximum and minimum forecasts serve as upper and lower boundaries for waste generation. This report provides the maximum and minimum forecast by waste treatability group for operation, decontamination and decommissioning, and ER activities.

  11. On Maximum Norm of Exterior Product and A Conjecture of C.N. Yang

    E-Print Network [OSTI]

    Zhilin Luo

    2015-01-08T23:59:59.000Z

    Let $V$ be a finite dimensional inner product space over $\\mathbb{R}$ with dimension $n$, where $n\\in \\mathbb{N}$, $\\wedge^{r}V$ be the exterior algebra of $V$, the problem is to find $\\max_{\\| \\xi \\| = 1, \\| \\eta \\| = 1}\\| \\xi \\wedge \\eta \\|$ where $k,l$ $\\in \\mathbb{N},$ $\\forall \\xi \\in \\wedge^{k}V, \\eta \\in \\wedge^{l}V.$ This is a problem suggested by the famous Nobel Prize Winner C.N. Yang. He solved this problem for $k\\leq 2$ in [1], and made the following \\textbf{conjecture} in [2] : If $n=2m$, $k=2r$, $l=2s$, then the maximum is achieved when $\\xi_{max} = \\frac{\\omega^{k}}{\\| \\omega^{k}\\|}, \\eta_{max} = \\frac{\\omega^{l}}{\\| \\omega^{l}\\|}$, where $ \\omega = \\Sigma_{i=1}^m e_{2i-1}\\wedge e_{2i}, $ and $\\{e_{k}\\}_{k=1}^{2m}$ is an orthonormal basis of V. From a physicist's point of view, this problem is just the dual version of the easier part of the well-known Beauzamy-Bombieri inequality for product of polynomials in many variables, which is discussed in [4]. Here the duality is referred as the well known Bose-Fermi correspondence, where we consider the skew-symmetric algebra(alternative forms) instead of the familiar symmetric algebra(polynomials in many variables) In this paper, for two cases we give estimations of the maximum of exterior products, and the Yang's conjecture is answered partially under some special cases.

  12. MADmap: A Massively Parallel Maximum-Likelihood Cosmic Microwave Background Map-Maker

    SciTech Connect (OSTI)

    Cantalupo, Christopher; Borrill, Julian; Jaffe, Andrew; Kisner, Theodore; Stompor, Radoslaw

    2009-06-09T23:59:59.000Z

    MADmap is a software application used to produce maximum-likelihood images of the sky from time-ordered data which include correlated noise, such as those gathered by Cosmic Microwave Background (CMB) experiments. It works efficiently on platforms ranging from small workstations to the most massively parallel supercomputers. Map-making is a critical step in the analysis of all CMB data sets, and the maximum-likelihood approach is the most accurate and widely applicable algorithm; however, it is a computationally challenging task. This challenge will only increase with the next generation of ground-based, balloon-borne and satellite CMB polarization experiments. The faintness of the B-mode signal that these experiments seek to measure requires them to gather enormous data sets. MADmap is already being run on up to O(1011) time samples, O(108) pixels and O(104) cores, with ongoing work to scale to the next generation of data sets and supercomputers. We describe MADmap's algorithm based around a preconditioned conjugate gradient solver, fast Fourier transforms and sparse matrix operations. We highlight MADmap's ability to address problems typically encountered in the analysis of realistic CMB data sets and describe its application to simulations of the Planck and EBEX experiments. The massively parallel and distributed implementation is detailed and scaling complexities are given for the resources required. MADmap is capable of analysing the largest data sets now being collected on computing resources currently available, and we argue that, given Moore's Law, MADmap will be capable of reducing the most massive projected data sets.

  13. Development of Best Practices for Shell Egg Disinfection Based upon Efficacy and Egg Quality

    E-Print Network [OSTI]

    Al-Ajeeli, Morouj N

    2013-12-04T23:59:59.000Z

    ; 2) assess the efficacy of chlorine, quaternary ammonium compounds (QAC), peracetic acid alone or in combination with ultraviolet (UV) light and hydrogen peroxide (H2O2) (3.5%) in combination with UV light as post-wash sanitizers against aerobic plate...

  14. ORIGINAL ARTICLE Enhanced therapeutic efficacy of IL-12, but not GM-CSF,

    E-Print Network [OSTI]

    Cai, Long

    ORIGINAL ARTICLE Enhanced therapeutic efficacy of IL-12, but not GM-CSF, expressing oncolytic herpes simplex virus for transgenic mouse derived prostate cancers S Varghese1,2 , SD Rabkin1,2 , R Liu1 and Harvard Medical School, Boston, MA, USA Replication competent oncolytic herpes simplex viruses (HSV

  15. Heat of the Moment: Characterizing the Efficacy of Thermal Camera-Based Attacks

    E-Print Network [OSTI]

    Heat of the Moment: Characterizing the Efficacy of Thermal Camera-Based Attacks Keaton Mowery UC to analyze the data. First, we present code recovery re- sults from human review of our test data set lock on an industrial safe, he found that body heat from the user transferred to the individual keys

  16. Efficacy-aware Business Process Modeling Matthias Lohrmann and Manfred Reichert

    E-Print Network [OSTI]

    Ulm, Universität

    Efficacy-aware Business Process Modeling Matthias Lohrmann and Manfred Reichert Ulm University. In business process design, business objective models can ful- fill the role of formal requirement definitions for progressive appli- cations like automated process optimization. Key words: Business Process Modeling

  17. We compared the efficacy of positive pressure ventilation (PPV) vs negative pressure ventilation (NPV) in providing

    E-Print Network [OSTI]

    Shadmehr, Reza

    the rationale for the use ofintermittent assisted ventilation is based on the premise that it alleviates muscleWe compared the efficacy of positive pressure ventilation (PPV) vs negative pressure ventilationEMG), minute ventilation (VE),tidal volume (VT), and end-tidal CO (etCOÃ during 15 minutes of PPV and NPV

  18. Young drivers and the efficacy of the Texas drug and alcohol driving awareness program

    E-Print Network [OSTI]

    Darnell, Richard

    2009-05-15T23:59:59.000Z

    The purpose of this study was to examine the efficacy of the Texas Drug and Alcohol Driving Awareness Program (TDADAP) in relation to alcohol-related offenses among young drivers. Participants in this study were students in pre-license programs...

  19. Comparison of the Efficacy of Popular Weight Loss Programs in Sedentary Overweight Women

    E-Print Network [OSTI]

    Baetge, Claire

    2014-08-06T23:59:59.000Z

    This study compared the efficacy of the Curves® Complete 90-day Challenge (CC), Weight Watchers® Points Plus (WW), Jenny Craig® At Home (JC), and Nutrisystem® Advance Select™ (NS) on weight loss, body composition and/or markers of health and fitness...

  20. Neuropharmacology and analgesia Comparative efficacy of 3 soluble epoxide hydrolase inhibitors

    E-Print Network [OSTI]

    Hammock, Bruce D.

    Neuropharmacology and analgesia Comparative efficacy of 3 soluble epoxide hydrolase inhibitors in rat neuropathic and inflammatory pain models Karen Wagner, Bora Inceoglu, Hua Dong, Jun Yang, Sung Hee Inflammatory pain Diabetic neuropathic pain Epoxygenated fatty acid a b s t r a c t Epoxy-fatty acids have been