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Optical Properties of Radio-Selected Narrow Line Seyfert 1 Galaxies (open access)

Optical Properties of Radio-Selected Narrow Line Seyfert 1 Galaxies

We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 galaxies (NLS1s). These objects are a subset of the First Bright Quasar Survey (FBQS) and were initially detected at 20 cm (flux density limit {approx} 1 mJy) in the VLA FIRST Survey. We run Spearman rank correlation tests on several sets of parameters and conclude that, except for their radio properties, radio-selected NLS1 galaxies do not exhibit significant differences from traditional NLS1 galaxies. Our results are also in agreement with previous studies suggesting that NLS1 galaxies have small black hole masses that are accreting very close to the Eddington rate. We have found 16 new radio-loud NLS1 galaxies, which increases the number of known radio-loud NLS1 galaxies by a factor of {approx} 5.
Date: January 5, 2006
Creator: Whalen, J.; Laurent-Muehleisen, S. A.; Moran, E. C. & Becker, R. H.
System: The UNT Digital Library
An Integrated Hydrologic Bayesian Multi-Model Combination Framework: Confronting Input, parameter and model structural uncertainty in Hydrologic Prediction (open access)

An Integrated Hydrologic Bayesian Multi-Model Combination Framework: Confronting Input, parameter and model structural uncertainty in Hydrologic Prediction

This paper presents a new technique--Integrated Bayesian Uncertainty Estimator (IBUNE) to account for the major uncertainties of hydrologic rainfall-runoff predictions explicitly. The uncertainties from the input (forcing) data--mainly the precipitation observations and from the model parameters are reduced through a Monte Carlo Markov Chain (MCMC) scheme named Shuffled Complex Evolution Metropolis (SCEM) algorithm which has been extended to include a precipitation error model. Afterwards, the Bayesian Model Averaging (BMA) scheme is employed to further improve the prediction skill and uncertainty estimation using multiple model output. A series of case studies using three rainfall-runoff models to predict the streamflow in the Leaf River basin, Mississippi are used to examine the necessity and usefulness of this technique. The results suggests that ignoring either input forcings error or model structural uncertainty will lead to unrealistic model simulations and their associated uncertainty bounds which does not consistently capture and represent the real-world behavior of the watershed.
Date: May 5, 2006
Creator: Ajami, N. K.; Duan, Q. & Sorooshian, S.
System: The UNT Digital Library
Results from the CDX-U Lithium Wall and NSTX Lithium Pallet Injection and Evaporation Experiments (open access)

Results from the CDX-U Lithium Wall and NSTX Lithium Pallet Injection and Evaporation Experiments

CDX-U has been operated with the vacuum vessel wall and limiter surfaces nearly completely coated with lithium, producing dramatic improvements to plasma performance. Discharges achieved global energy confinement times up to 6 ms, exceeding previous CDX-U results by a factor of 5, and ITER98P(y,1) scaling by 2-3. Lithium wall coatings up to 1000 {angstrom} thick were applied between discharges by electron-beam-induced evaporation of a lithium-filled limiter and vapor deposition from a resistively heated oven. The e-beam power was modest (1.6 kW) but it produced up to 60 MW/m2 power density in a 0.3 cm{sup 2} spot; the duration was up to 300 s. Convective transport of heat away from the beam spot was so effective that the entire lithium inventory (140 g) was heated to evaporation (400-500 C) and there was no observable hot spot on the lithium surface within the beam footprint. These results are promising for use of lithium plasma-facing components in reactor scale devices. Lithium coating has also been applied to NSTX carbon plasma-facing surfaces, to control the density rise during long-duration H-modes for non-inductive current sustainment. First, lithium pellets were injected into sequences of Ohmically heated helium plasmas in both center stack limiter (CSL) and lower …
Date: October 5, 2006
Creator: Majeski, R; Kugel, H; Bell, M; Bell, R; Beiersdorfer, P; Bush, C et al.
System: The UNT Digital Library
Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z~6 Quasars II: A Sample of 19 Quasars (open access)

Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z~6 Quasars II: A Sample of 19 Quasars

We study the evolution of the ionization state of the intergalactic medium (IGM) at the end of the reionization epoch using moderate resolution spectra of a sample of nineteen quasars at 5.74 < z{sub em} < 6.42 discovered in the Sloan Digital Sky Survey. Three methods are used to trace IGM properties: (a) the evolution of the Gunn-Peterson (GP) optical depth in the Ly{alpha}, {beta}, and {gamma} transitions; (b) the distribution of lengths of dark absorption gaps, and (c) the size of HII regions around luminous quasars. Using this large sample, we find that the evolution of the ionization state of the IGM accelerated at z > 5.7: the GP optical depth evolution changes from {tau}{sub GP}{sup eff} {approx} (1 + z){sup 4.3} to (1 + z){sup {approx}> 11}, and the average length of dark gaps with {tau} > 3.5 increases from < 10 to > 80 comoving Mpc. The dispersion of IGM properties along different lines of sight also increases rapidly, implying fluctuations by a factor of {approx}> 4 in the UV background at z > 6, when the mean free path of UV photons is comparable to the correlation length of the star forming galaxies that are thought …
Date: January 5, 2006
Creator: Fan, X; Strauss, M A; Becker, R H; White, R L; Gunn, J E; Knapp, G R et al.
System: The UNT Digital Library
Higher Curvature Effects in the ADD and RS Models (open access)

Higher Curvature Effects in the ADD and RS Models

Over the last few years several extra-dimensional models have been introduced in attempt to deal with the hierarchy problem. These models can lead to rather unique and spectacular signatures at Terascale colliders such as the LHC and ILC. The ADD and RS models, though quite distinct, have many common feature including a constant curvature bulk, localized Standard Model(SM) fields and the assumption of the validity of the EH action as a description of gravitational interactions.
Date: July 5, 2006
Creator: Rizzo, Thomas G.
System: The UNT Digital Library
Measurement of the Pseudoscalar Decay Constantf_D_s Using Charm-Tagged Events in e+e- Collisions atsqrt{s}=10.58 GeV (open access)

Measurement of the Pseudoscalar Decay Constantf_D_s Using Charm-Tagged Events in e+e- Collisions atsqrt{s}=10.58 GeV

Using 230.2 fb{sup -1} of e{sup +}e{sup -} annihilation data collected with the BABAR detector at and near the peak of the {Upsilon}(4S) resonance, 489 {+-} 55 events containing the pure leptonic decay D{sub s}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}} have been isolated in charm-tagged events. The ratio of partial widths {Lambda}(D{sub s}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}})/{Lambda}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) is measured to be 0.143 {+-} 0.018 {+-} 0.006 allowing a determination of the pseudoscalar decay constant f{sub D{sub 2}} = (283 {+-} 17 {+-} 7 {+-} 14) MeV. The errors are statistical, systematic, and from the D{sub s}{sup +} {yields} {phi}{pi}{sup +} branching ratio, respectively.
Date: September 5, 2006
Creator: Aubert, B.
System: The UNT Digital Library
North Korea: Leadership, Foreign Policy, Military, Decision Making (open access)

North Korea: Leadership, Foreign Policy, Military, Decision Making

None
Date: September 5, 2006
Creator: Kim, S. J.
System: The UNT Digital Library
Large-eddy simulation of very large kinetic and magnetic Reynolds number isotropic magnetohydrodynamic turbulence using a spectral subgrid model (open access)

Large-eddy simulation of very large kinetic and magnetic Reynolds number isotropic magnetohydrodynamic turbulence using a spectral subgrid model

A spectral subggrid-scale eddy viscosity and magnetic resisitivity model based on the eddy-damped quasi-normal Markovian (EDQNM) spectral kinetic and magnetic energy transfer presented in [12] is used in large-eddy simulation (LES) of large kinetic and magnetic Reynold number magneto-hydrodynamic (MHD) turbulence. The proposed model is assessed via a posteri tests on three-dimensional, incompressible, isotropic, non-helical, freely-decaying MHD turbulence at asymptotically large Reynolds numbers. Using LES with an initial condition characterized by an Alfv{acute e}n ratio of kinetic to magnetic energy {tau}{sub A} equal to unity, it is shown that at the kinetic energy spectrum E{sub K}(k) and magnetic energy spectrum E{sub M}(k) exhibit Kolmogorov -5/3 inertial subrange scalings in the LES, consistent with the EDQNM model.
Date: July 5, 2006
Creator: Gomez, T; Sagaut, P; Schilling, O & Zhou, Y
System: The UNT Digital Library
LSST Camera Optics (open access)

LSST Camera Optics

The Large Synoptic Survey Telescope (LSST) is a unique, three-mirror, modified Paul-Baker design with an 8.4m primary, a 3.4m secondary, and a 5.0m tertiary feeding a camera system that includes corrector optics to produce a 3.5 degree field of view with excellent image quality (<0.3 arcsecond 80% encircled diffracted energy) over the entire field from blue to near infra-red wavelengths. We describe the design of the LSST camera optics, consisting of three refractive lenses with diameters of 1.6m, 1.0m and 0.7m, along with a set of interchangeable, broad-band, interference filters with diameters of 0.75m. We also describe current plans for fabricating, coating, mounting and testing these lenses and filters.
Date: June 5, 2006
Creator: Olivier, S. S.; Seppala, L.; Gilmore, K.; Hale, L. & Whistler, W.
System: The UNT Digital Library
ACCUMULATION OF RADIOCESIUM BY MUSHROOMS IN THE ENVIRONMENT: A LITERATURE REVIEW AND IMAGE GALLERY (open access)

ACCUMULATION OF RADIOCESIUM BY MUSHROOMS IN THE ENVIRONMENT: A LITERATURE REVIEW AND IMAGE GALLERY

During the last 50 years, a large amount of information on radionuclide accumulators or 'sentinel-type' organisms in the environment has been published. Much of this work focused on the risks of food-chain transfer of radionuclides to higher organisms such as reindeer and man. However, until the 1980's and 1990's, there has been little published data on the radiocesium ({sup 134}Cs and {sup 137}Cs) accumulation by mushrooms. This presentation will consist of a review of the published data for {sup 134,137}Cs accumulation by mushrooms in nature. The review will consider the time of sampling, sample location characteristics, the radiocesium source term and other aspects that promote {sup 134,137}Cs uptake by mushrooms. This review will focus on published data for mushrooms that demonstrate a large propensity for use in the environmental biomonitoring of radiocesium contamination. It will also provide photographs and descriptions of habitats for many of these mushrooms to facilitate their collection for biomonitoring.
Date: November 5, 2006
Creator: Duff, M & Mary Ramsey, M
System: The UNT Digital Library
Multiaperture U BV RIzJHK Photometry of Galaxies in the Coma Cluster (open access)

Multiaperture U BV RIzJHK Photometry of Galaxies in the Coma Cluster

We present a set of UBV RIzJHKs photometry for 745 J +H band selected objects in a 22:5{prime} x 29:2{prime} region centered on the core of the Coma cluster. This includes 516 galaxies and is at least 80% complete to H = 16, with a spectroscopically complete sample of 111 cluster members (nearly all with morphological classification) for H < 14:5. For each object we present total Kron (1980) magnitudes and aperture photometry. As an example, we use these data to derive color-magnitude relations for Coma early-type galaxies, measure the intrinsic scatter of these relations and its dependence on galaxy mass, and address the issue of color gradients. We find that the color gradients are mild and that the intrinsic scatter about the color-magnitude relation is small ({approx} 0:05 mag in U-V and less than {approx} 0:03 in B-R, V-I, or J-K). There is no evidence that the intrinsic scatter varies with galaxy luminosity, suggesting that the cluster red sequence is established at early epochs over a range of {approx} 100 in stellar mass.
Date: December 5, 2006
Creator: Eisenhardt, P. R.; De Propris, R.; Gonzalez, A. H.; Stanford, S. A.; Dickinson, M. & Wang, M. C.
System: The UNT Digital Library
Progress on the Europium Neutron-Capture Study using DANCE (open access)

Progress on the Europium Neutron-Capture Study using DANCE

The accurate measurement of neutron-capture cross sections of the Eu isotopes is important for many reasons including nuclear astrophysics and nuclear diagnostics. Neutron capture excitation functions of {sup 151,153}Eu targets were measured recently using a 4{pi} {gamma}-ray calorimeter array DANCE located at the Los Alamos Neutron Science Center for E{sub n} = 0.1-100 keV. The progress on the data analysis efforts is given in the present paper. The {gamma}-ray multiplicity distributions for the Eu targets and Be backing are significantly different. The {gamma}-ray multiplicity distribution is found to be the same for different neutron energies for both {sup 151}Eu and {sup 153}Eu. The statistical simulation to model the {gamma}-ray decay cascade is summarized.
Date: September 5, 2006
Creator: Agvaanluvsan, U.; Becker, J. A.; Macri, R. A.; Parker, W.; Wilk, P.; Wu, C. Y. et al.
System: The UNT Digital Library
Measurements of |V_{cb}| and |V_{ub}| at BaBar (open access)

Measurements of |V_{cb}| and |V_{ub}| at BaBar

We report on new measurements of the Cabibbo-Kobayashi-Maskawa matrix elements |V{sub cb}| and |V{sub ub}| with inclusive and exclusive semileptonic B decays, highlighting the recent precision measurements with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.
Date: January 5, 2006
Creator: Godang, Romulus & U., /Mississippi
System: The UNT Digital Library
Potential Flammable Gas Explosion in the TRU Vent and Purge Machine (open access)

Potential Flammable Gas Explosion in the TRU Vent and Purge Machine

The objective of the analysis was to determine the failure of the Vent and Purge (V&P) Machine due to potential explosion in the Transuranic (TRU) drum during its venting and/or subsequent explosion in the V&P machine from the flammable gases (e.g., hydrogen and Volatile Organic Compounds [VOCs]) vented into the V&P machine from the TRU drum. The analysis considers: (a) increase in the pressure in the V&P cabinet from the original deflagration in the TRU drum including lid ejection, (b) pressure wave impact from TRU drum failure, and (c) secondary burns or deflagrations resulting from excess, unburned gases in the cabinet area. A variety of cases were considered that maximized the pressure produced in the V&P cabinet. Also, cases were analyzed that maximized the shock wave pressure in the cabinet from TRU drum failure. The calculations were performed for various initial drum pressures (e.g., 1.5 and 6 psig) for 55 gallon TRU drum. The calculated peak cabinet pressures ranged from 16 psig to 50 psig for various flammable gas compositions. The blast on top of cabinet and in outlet duct ranged from 50 psig to 63 psig and 12 psig to 16 psig, respectively, for various flammable gas compositions. The …
Date: April 5, 2006
Creator: Vincent, A
System: The UNT Digital Library
In vivo cellular visualization of the human retina using optical coherence tomography and adaptive optics (open access)

In vivo cellular visualization of the human retina using optical coherence tomography and adaptive optics

Optical coherence tomography (OCT) sees the human retina sharply with adaptive optics. In vivo cellular visualization of the human retina at micrometer-scale resolution is possible by enhancing Fourier-domain optical-coherence tomography with adaptive optics, which compensate for the eye's optical aberrations.
Date: January 5, 2006
Creator: Olivier, S. S.; Jones, S. M.; Chen, D. C.; Zawadzki, R. J.; Choi, S. S.; Laut, S. P. et al.
System: The UNT Digital Library
Development of a Low Loss, High Dielectric Strength Microwave Substrate (open access)

Development of a Low Loss, High Dielectric Strength Microwave Substrate

This work describes a comparison of two candidate materials for pulse forming line fabrication with respect to bulk dielectric breakdown, frequency response of relative permittivity and dielectric loss. One material is a commercially available microwave substrate material that can be procured in sheet form without a high voltage specification while the other is a newly developed material that also comes in sheet form that can also be cast between the electrodes.
Date: June 5, 2006
Creator: Sanders, D; Sampayan, S; Caporaso, G; Rhodes, M; Watson, J; Slenes, K et al.
System: The UNT Digital Library
Filtered cathodic arc deposition with ion-species-selectivebias (open access)

Filtered cathodic arc deposition with ion-species-selectivebias

A dual-cathode arc plasma source was combined with acomputer-controlled bias amplifier such as to synchronize substrate biaswith the pulsed production of plasma. In this way, bias can be applied ina material-selective way. The principle has been applied to the synthesismetal-doped diamond-like carbon films, where the bias was applied andadjusted when the carbon plasma was condensing, and the substrate was atground when the metal was incorporated. In doing so, excessive sputteringby too-energetic metal ions can be avoided while the sp3/sp2 ratio can beadjusted. It is shown that the resistivity of the film can be tuned bythis species-selective bias. The principle can be extended tomultiple-material plasma sources and complex materials
Date: October 5, 2006
Creator: Anders, Andre; Pasaja, Nitisak; Sansongsiri, Sakon & Lim, SunnieH.N.
System: The UNT Digital Library
Creation of hot radiation environments in laser-driven targets (open access)

Creation of hot radiation environments in laser-driven targets

None
Date: January 5, 2006
Creator: Hinkel, D. E.; Schneider, M. B.; Young, B. K.; Langdon, A. B.; Williams, E. A.; Rosen, M. D. et al.
System: The UNT Digital Library
Towards the NNLL Precision in the Decay $\bar B \rightarrow X_s \gamma$ (open access)

Towards the NNLL Precision in the Decay $\bar B \rightarrow X_s \gamma$

The present NLL prediction for the decay rate of the rare inclusive process {bar B} {yields} X{sub s}{gamma} has a large uncertainty due to the charm mass renormalization scheme ambiguity. We estimate that this uncertainty will be reduced by a factor of 2 at the NNLL level. This is a strong motivation for the on-going NNLL calculation, which will thus significantly increase the sensitivity of the observable {bar B} {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM. We also give a brief status report of the NNLL calculation.
Date: January 5, 2006
Creator: Asatrian, Hrachia M.; Hovhannisyan, Artyom; Poghosyan, Vahagn; Inst., /Yerevan Phys.; Greub, Christoph; U., /Bern et al.
System: The UNT Digital Library
A New HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring (open access)

A New HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring

At high currents and small bunch lengths beam line components in the PEP-II B-factory experience RF induced heating from higher order RF modes (HOMs) produced by scattered intense beam fields. A design for a passive HOM water cooled absorber for the PEP-II low energy ring is presented. This device is situated near HOM producing beamline components such as collimators and provide HOM damping for dipole and quadrupole modes without impacting beam impedance. We optimized the impedance characteristics of the device through the evaluation of absorber effectiveness for specific modes using scattering parameter and wakefield analysis. Operational results are presented and agree very well with the predicted effectiveness.
Date: September 5, 2006
Creator: Weathersby, Stephen; Kosovsky, Michael; Kurita, Nadine; Novokhatski, Alexander & Seeman, John
System: The UNT Digital Library
SDSS J1029+2623: A Gravitationally Lensed Quasar with an Image Separation of 22.5 Arcseconds (open access)

SDSS J1029+2623: A Gravitationally Lensed Quasar with an Image Separation of 22.5 Arcseconds

None
Date: December 5, 2006
Creator: Inada, N.; Oguri, M.; Morokuma, T.; Doi, M.; Yasuda, N.; Becker, R. H. et al.
System: The UNT Digital Library
Measurements of the Branching Fractions and CP Asymmetries of B -> D0_CP K Decays (open access)

Measurements of the Branching Fractions and CP Asymmetries of B -> D0_CP K Decays

We present a study of the decay B{sup -} {yields} D{sub (CP)}{sup 0} K{sup -} and its charge conjugate, where D{sub (CP)}{sup 0} is reconstructed in CP-even, CP-odd, and non-CP flavor eigenstates, based on a sample of 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. We measure the partial-rate charge asymmetries AC{sub CP{+-}} and the ratios R{sub CP{+-}} of the B {yields} D{sup 0} K decay branching fractions as measured in CP{+-} and non-CP D{sup 0} decays: A{sub CP+} = 0.35 {+-} 0.13(stat) {+-} 0.04(syst), A{sub CP-} = -0.06 {+-} 0.13(stat) {+-} 0.04(syst), R{sub CP+} = 0.90 {+-} 0.12(stat) {+-} 0.04(syst), R{sub CP-} = 0.86 {+-} 0.10(stat) {+-} 0.05(syst).
Date: January 5, 2006
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
System: The UNT Digital Library
Optics of the ILC Extraction Line for 2mrad Crossing Angle (open access)

Optics of the ILC Extraction Line for 2mrad Crossing Angle

The ILC extraction line for 2 mrad crossing angle is under development by the SLAC-BNL-UK-France task force collaboration. This report describes the progress in the 2 mrad optics design which includes the changes to the final focus doublet, the complete optics for the extraction diagnostics, and the changes to the sextupole and collimation systems. The results of disrupted beam tracking simulations are presented.
Date: January 5, 2006
Creator: Nosochkov, Y.; Moffeit, K.; Seryi, A.; Spencer, C.; Woods, M.; Angal-Kalinin, D. et al.
System: The UNT Digital Library
A Photon Free Method to Solve Radiation Transport Equations (open access)

A Photon Free Method to Solve Radiation Transport Equations

The multi-group discrete-ordinate equations of radiation transfer is solved for the first time by Newton's method. It is a photon free method because the photon variables are eliminated from the radiation equations to yield a N{sub group}XN{sub direction} smaller but equivalent system of equations. The smaller set of equations can be solved more efficiently than the original set of equations. Newton's method is more stable than the Semi-implicit Linear method currently used by conventional radiation codes.
Date: September 5, 2006
Creator: Chang, B.
System: The UNT Digital Library