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A Different Look at Dark Energy and the Time Variation of Fundamental Constants (open access)

A Different Look at Dark Energy and the Time Variation of Fundamental Constants

This paper makes the simple observation that a fundamental length, or cutoff, in the context of Friedmann-Lemaitre-Robertson-Walker (FRW) cosmology implies very different things than for a static universe. It is argued that it is reasonable to assume that this cutoff is implemented by fixing the number of quantum degrees of freedom per co-moving volume (as opposed to a Planck volume) and the relationship of the vacuum-energy of all of the fields in the theory to the cosmological constant (or dark energy) is re-examined. The restrictions that need to be satisfied by a generic theory to avoid conflicts with current experiments are discussed, and it is shown that in any theory satisfying these constraints knowing the difference between w and minus one allows one to predict w. It is argued that this is a robust result and if this prediction fails the idea of a fundamental cutoff of the type being discussed can be ruled out. Finally, it is observed that, within the context of a specific theory, a co-moving cutoff implies a predictable time variation of fundamental constants. This is accompanied by a general discussion of why this is so, what are the strongest phenomenological limits upon this predicted variation, …
Date: February 7, 2011
Creator: Weinstein, Marvin
Object Type: Article
System: The UNT Digital Library
Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons (open access)

Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons

We show that the unmeasured distribution of linearly polarized gluons inside unpolarized hadrons can be directly probed in jet or heavy quark pair production both in electron-hadron and hadron-hadron collisions. We present expressions for the simplest cos 2{phi} asymmetries and estimate their maximal value in the particular case of electron-hadron collisions. Measurements of the linearly polarized gluon distribution in the proton should be feasible in future EIC or LHeC experiments.
Date: February 7, 2011
Creator: Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J. & Pisano, Cristian
Object Type: Article
System: The UNT Digital Library
Study of \Bpilnu and \Brholnu decays and determination of \Vub at \babar (open access)

Study of \Bpilnu and \Brholnu decays and determination of \Vub at \babar

The authors report a measurement of the branching fractions for B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} and B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu} decays using charged and neutral B decays with isospin constraints. They find {beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.41 {+-} 0.05 {+-} 0.07) x 10{sup -4}, and {beta}(B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}) = (1.75 {+-} 0.15 {+-} 0.27) x 10{sup -4}, where the first error is statistical and the second is systematic. They measure {Delta}{beta}/{Delta}q{sup 2}, with 6 q{sup 2} bins for B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} and 3 q{sup 2} bins for B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}, and compare the distributions in data with theoretical predictions for the form factors. They use these branching fractions and form-factor calculations to determine |V{sub ub}|. Based on a combined fit to the FNAL/MILC lattice QCD calculation and data over the full q{sup 2} range, they find |V{sub ub}| = (2.95 {+-} 0.31) x 10{sup -3}.
Date: February 7, 2011
Creator: Wulsin, H.Wells
Object Type: Article
System: The UNT Digital Library
Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction (open access)

Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction

None
Date: February 7, 2011
Creator: Lu, T; Plomer, M; Luo, Z; Sarathy, S M; Pitz, W J; Som, S et al.
Object Type: Article
System: The UNT Digital Library
Data Summary Report for teh Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington (open access)

Data Summary Report for teh Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington

This data summary report summarizes the investigation results to evaluate the nature and distribution of Hanford Site-related contaminants present in the Columbia River. As detailed in DOE/RL-2008-11, more than 2,000 environmental samples were collected from the Columbia River between 2008 and 2010. These samples consisted of island soil, sediment, surface water, groundwater upwelling (pore water, surface water, and sediment), and fish tissue.
Date: February 7, 2011
Creator: Hulstrom, L.
Object Type: Report
System: The UNT Digital Library
Naturalness from Runaways in Direct Mediation (open access)

Naturalness from Runaways in Direct Mediation

Postulating that the NMSSM singlet is a meson of a microscopic confining theory opens up new model-building possibilities. Based on this, we construct calculable models of direct mediation that solve the {mu}/B{mu} problem and simultaneously lead to realistic phenomenology. The singlet that couples to the Higgs fields develops a runaway produced by soft interactions, then stabilized by a small superpotential perturbation. The mechanism is first realized in an O'Raifeartaigh model of direct gauge mediation with metastable supersymmetry breaking. Focusing then on the microscopic theory, we argue that super QCD with massless and massive flavors in the free magnetic phase gives rise to this dynamics in the infrared. A deformation of the SQCD superpotential leads to large spontaneous R-symmetry breaking, gaugino masses naturally at the scale of the Higgs mass parameters, and absence of CP violating phases.
Date: February 7, 2011
Creator: Schafer-Nameki, Sakura; Tamarit, Carlos & Torroba, Gonzalo
Object Type: Article
System: The UNT Digital Library
Efficiency of the LIFE Laser - Response to a Request for Information from the National Research Council (open access)

Efficiency of the LIFE Laser - Response to a Request for Information from the National Research Council

None
Date: February 7, 2011
Creator: Deri, R. J.; Erlandson, A. C. & Bayramian, A. J.
Object Type: Report
System: The UNT Digital Library
[Funeral Program for Lynda Loyace Cooper-Waith, February 7, 2011] (open access)

[Funeral Program for Lynda Loyace Cooper-Waith, February 7, 2011]

Funeral program for Lynda Loyace Cooper-Waith, born May 21, 1949 and died January 30, 2011. The funeral was held February 7, 2011 at Calvary Baptist Church, officiated by Kevin Nelson. Funeral arrangements were made through Carter-Taylor-Williams Mortuary, and she was buried in Fort Sam Houston Cemetery near San Antonio, Texas.
Date: February 7, 2011
Creator: unknown
Object Type: Pamphlet
System: The Portal to Texas History
Sweetwater Reporter (Sweetwater, Tex.), Vol. 113, No. 073, Ed. 1 Monday, February 7, 2011 (open access)

Sweetwater Reporter (Sweetwater, Tex.), Vol. 113, No. 073, Ed. 1 Monday, February 7, 2011

Daily newspaper from Sweetwater, Texas that includes local, state, and national news along with advertising.
Date: February 7, 2011
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors (open access)

Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors

We study the reactions e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sup (/)} in the single-tag mode and measure the {gamma}{gamma}* {yields} {eta}{sup (/)} transition form factors in the momentum transfer range from 4 to 40 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.
Date: February 7, 2011
Creator: del Amo Sanchez et al, P.
Object Type: Article
System: The UNT Digital Library
Solid state NMR method development and studies of biological and biomimetic nanocomposites (open access)

Solid state NMR method development and studies of biological and biomimetic nanocomposites

This thesis describes application and development of advanced solid-state nuclear magnetic resonance techniques for complex materials, in particular organic-inorganic nanocomposites and thermoelectric tellurides. The apatite-collagen interface, essential for understanding the biomineralization process in bone and engineering the interface for controlled bio-mimetic synthesis and optimized mechanical properties, is buried within the nanocomposite of bone. We used multinuclear solid-state NMR to study the composition and structure of the interface. Citrate has been identified as the main organic molecule strongly bound to the apatite surface with a density of 1/(2 nm){sup 2}, covering 1/6 of the total surface area in bovine bone. Citrate provides more carboxylate groups, one of the key functional groups found to affect apatite nucleation and growth, than all the non-collagenous proteins all together in bone; thus we propose that citrate stabilizes apatite crystals at a very small thickness of {approx}3 nm (4 unit cells) to increase bone fracture tolerance. The hypothesis has been confirmed in vitro by adding citrate in the bio-mimetic synthesis of polymerhydroxyapatite nanocomposites. The results have shown that the size of hydroxyapatite nanocrystals decreases as increasing citrate concentration. With citrate concentrations comparable to that in body fluids, similar-sized nanocrystals as in bone have been produced. Besides …
Date: February 7, 2011
Creator: Hu, Yanyan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Physics of the Gas Attenuator for the Linac Coherent Light Source (LCLS) (open access)

The Physics of the Gas Attenuator for the Linac Coherent Light Source (LCLS)

A systematic assessment of a variety of physics issues affecting the performance of the LCLS X-ray beam attenuator is presented. Detailed analysis of the gas flow in the gas attenuator and in the apertures is performed. A lot of attention is directed towards the gas ionization and heating by intense X-ray pulses. The role of these phenomena in possible deviations of the attenuation coefficient from its 'dialed in' value is evaluated and found small in most cases. Other sources of systematic and statistical errors are also discussed. The regimes where the errors may reach a few percent correspond to the lower X-ray energies (less than 2 keV) and highest beam intensities. Other effects discussed include chemical interaction of the gas with apertures, shock formation in the transonic flow in the apertures of the attenuator, generation of electromagnetic wakes in the gas, and head-to-tail variation of the attenuation caused by the ionization of gas or solid. Possible experimental tests of the consistency of the physics assumptions used in the concept of the gas attenuator are discussed. Interaction of X-rays with the solid attenuator (that will be used at higher X-ray energies, from 2.5 to 8 keV) is considered and thermo-mechanical effects …
Date: February 7, 2011
Creator: Ryutov, D. D.; Bionta, R. M.; Hau-Riege, S. P.; Kishiyama, K. I.; McMahon, D.; Roeben, M. D. et al.
Object Type: Report
System: The UNT Digital Library
Charm Spectroscopy from B Factories (open access)

Charm Spectroscopy from B Factories

A brief review of the excited D{sub s} and D mesons is presented. A precision measurement of the D{sub s1}(2536) mass and width parameters is reported by BABAR. Finally, a recent BABAR study of the D{pi} and D*{pi} final states shows first observations of the radial excitations of the D{sup 0}, D*{sup 0}, and D*{sup +}, as well as the L = 2 excited states of the D{sup 0} and D{sup +}, where L is the orbital angular momentum of the quarks.
Date: February 7, 2011
Creator: Benitez, J.
Object Type: Article
System: The UNT Digital Library
Small Column Ion Exchange Design and Safety Strategy (open access)

Small Column Ion Exchange Design and Safety Strategy

Small Column Ion Exchange (SCIX) is a transformational technology originally developed by the Department of Energy (DOE) Environmental Management (EM-30) office and is now being deployed at the Savannah River Site (SRS) to significantly increase overall salt processing capacity and accelerate the Liquid Waste System life-cycle. The process combines strontium and actinide removal using Monosodium Titanate (MST), Rotary Microfiltration, and cesium removal using Crystalline Silicotitanate (CST, specifically UOP IONSIV{reg_sign}IE-911 ion exchanger) to create a low level waste stream to be disposed in grout and a high level waste stream to be vitrified. The process also includes preparation of the streams for disposal, e.g., grinding of the loaded CST material. These waste processing components are technically mature and flowsheet integration studies are being performed including glass formulations studies, application specific thermal modeling, and mixing studies. The deployment program includes design and fabrication of the Rotary Microfilter (RMF) assembly, ion-exchange columns (IXCs), and grinder module, utilizing an integrated system safety design approach. The design concept is to install the process inside an existing waste tank, Tank 41H. The process consists of a feed pump with a set of four RMFs, two IXCs, a media grinder, three Submersible Mixer Pumps (SMPs), and all …
Date: February 7, 2011
Creator: Huff, T.; Rios-Armstrong, M.; Edwards, R. & Herman, D.
Object Type: Article
System: The UNT Digital Library
A 10,000 groove/mm multilayer coated grating for EUV spectroscopy (open access)

A 10,000 groove/mm multilayer coated grating for EUV spectroscopy

Ultra-high spectral resolution in the EUV and soft x-ray energy ranges requires the use of very high line density gratings with optimal design resulting in use of a Blazed Multilayer Grating (BMG) structure. Here we demonstrate the production of near-atomically perfect Si blazed substrates with an ultra-high groove density (10,000 l/mm) together with the measured and theoretical performance of an Al/Zr multilayer coating on the grating. A 1st order absolute efficiency of 13percent and 24.6percent was achieved at incidence angles of 11o and 36o respectively. Cross-sectional TEM shows the effect of smoothing caused by the surface mobility of deposited atoms and we correlate this effect with a reduction in peak diffraction efficiency. This work shows the high performance that can be achieved with BMGs based on small-period anisotropic etched Si substrates, but also the constraints imposed by the surface mobility of deposited species.
Date: February 7, 2011
Creator: Voronov, Dmytro; Anderson, Erik; Cambie, Rossana; Cabrini, Stefano; Dhuey, Scott; Goray, Leonid et al.
Object Type: Article
System: The UNT Digital Library
Trapped Electron Mode Turbulence Driven Intrinsic Rotation in Tokamak Plasmas (open access)

Trapped Electron Mode Turbulence Driven Intrinsic Rotation in Tokamak Plasmas

Recent progress from global gyrokinetic simulations in understanding the origin of intrinsic rotation in toroidal plasmas is reported with emphasis on electron thermal transport dominated regimes. The turbulence driven intrinsic torque associated with nonlinear residual stress generation by the fluctuation intensity and the intensity gradient in the presence of zonal flow shear induced asymmetry in the parallel wavenumber spectrum is shown to scale close to linearly with plasma gradients and the inverse of the plasma current. These results qualitatively reproduce empirical scalings of intrinsic rotation observed in various experiments. The origin of current scaling is found to be due to enhanced kll symmetry breaking induced by the increased radial variation of the safety factor as the current decreases. The physics origin for the linear dependence of intrinsic torque on pressure gradient is that both turbulence intensity and the zonal flow shear, which are two key ingredients for driving residual stress, increase with the strength of turbulence drive, which is R0/LTe and R0/Lne for the trapped electron mode. __________________________________________________
Date: February 7, 2011
Creator: W. X. Wang, T. S. Hahm, S. Ethier, and L.E. Zakharov
Object Type: Report
System: The UNT Digital Library
Design of Flexure-based Precision Transmission Mechanisms using Screw Theory (open access)

Design of Flexure-based Precision Transmission Mechanisms using Screw Theory

This paper enables the synthesis of flexure-based transmission mechanisms that possess multiple decoupled inputs and outputs of any type (e.g. rotations, translations, and/or screw motions), which are linked by designer-specified transmission ratios. A comprehensive library of geometric shapes is utilized from which every feasible concept that possesses the desired transmission characteristics may be rapidly conceptualized and compared before an optimal concept is selected. These geometric shapes represent the rigorous mathematics of screw theory and uniquely link a body's desired motions to the flexible constraints that enable those motions. This paper's impact is most significant to the design of nano-positioners, microscopy stages, optical mounts, and sensors. A flexure-based microscopy stage was designed, fabricated, and tested to demonstrate the utility of the theory.
Date: February 7, 2011
Creator: Hopkins, J B & Panas, R M
Object Type: Article
System: The UNT Digital Library
Oral History Interview with J. B. Young, February 7, 2011 transcript

Oral History Interview with J. B. Young, February 7, 2011

The National Museum of the Pacific War presents an oral interview with Reverend J.B. Young. Young enlisted in the Army Air Corps in December 1936. He became a cook and then was trained as an airplane mechanic. Young was sent to Hickam Field in Hawaii to serve as a crew chief on a B-17. He describes the attack on 7 December and how he taxied his plane out of danger and the patrols that they flew in the immediate aftermath. Young was then sent to New Caledonia where his plane flew photo reconnaissance missions for three months. They traveled to Australia and flew missions against Rabaul and Japanese ships in the Coral Sea. Young describes some notable incidents from this time. He returned to the US after 66 missions and remained there until the end of the war. Young retired from the Air Force in 1959.
Date: February 7, 2011
Creator: Young, J. B.
Object Type: Sound
System: The Portal to Texas History
A computational study of x-ray emission from high-Z x-ray sources on the National Ignition Facility laser (open access)

A computational study of x-ray emission from high-Z x-ray sources on the National Ignition Facility laser

None
Date: February 7, 2011
Creator: Colvin, J. D.; Fournier, K. B.; Kane, J.; Langer, S.; May, M. J. & Scott, H. A.
Object Type: Article
System: The UNT Digital Library
Photon Beamlines and Diagnostics at LCLS (open access)

Photon Beamlines and Diagnostics at LCLS

The Linac Coherent Light Source (LCLS) is the first hard-x-ray free electron laser in operation. The turn-on of LCLS was rapid and operation has been reliable. Performance has exceeded the design parameters in several areas. The photon energy output covers a range from 480 eV to over 9 keV; the pulse energy is typically 2-3 mJ, with a maximum of 4 mJ at 2 keV. Electron pulse lengths can be varied from 500 fs to shorter than 10 fs. A low-charge option at 20 pC is being explored, which delivers pulses shorter than 10 fs with a reduced pulse energy, typically around 0.2 mJ. On-demand, single-shot and multi-shot modes up to 60 Hz (planned is 120 Hz) can be made available. The photon diagnostics built for LCLS have been commissioned and provide measurements of various properties of the FEL beam, such as pulse energy, beam size and position, wavelength, and allows for intensity attenuation over the entire wavelength range. The two soft x-ray instruments, the Atomic Molecular and Optics (AMO) and Soft X-ray Material Science (SXR) stations, are fully operational and completed their second user run in mid September 2010. The third user run is scheduled from October to December …
Date: February 7, 2011
Creator: Moeller, S.; Arthur, J.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Edstrom, S. et al.
Object Type: Article
System: The UNT Digital Library
Oral History Interview with J. B. Young, February 7, 2011 (open access)

Oral History Interview with J. B. Young, February 7, 2011

The National Museum of the Pacific War presents an oral interview with Reverend J.B. Young. Young enlisted in the Army Air Corps in December 1936. He became a cook and then was trained as an airplane mechanic. Young was sent to Hickam Field in Hawaii to serve as a crew chief on a B-17. He describes the attack on 7 December and how he taxied his plane out of danger and the patrols that they flew in the immediate aftermath. Young was then sent to New Caledonia where his plane flew photo reconnaissance missions for three months. They traveled to Australia and flew missions against Rabaul and Japanese ships in the Coral Sea. Young describes some notable incidents from this time. He returned to the US after 66 missions and remained there until the end of the war. Young retired from the Air Force in 1959.
Date: February 7, 2011
Creator: Young, J. B.
Object Type: Text
System: The Portal to Texas History
The Express-Star (Chickasha, Okla.), Ed. 1 Monday, February 7, 2011 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Monday, February 7, 2011

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: February 7, 2011
Creator: Wray, Kelly
Object Type: Newspaper
System: The Gateway to Oklahoma History
Journal of the House of Representatives of Texas: 82nd Legislature, Regular Session, Monday, February 7, 2011 (open access)

Journal of the House of Representatives of Texas: 82nd Legislature, Regular Session, Monday, February 7, 2011

Proceedings of the House of Representatives of Texas for the #th day of the {{{type}}} session of the 82nd Legislature documenting legislation, reports, discussions, votes, and points-of-order.
Date: February 7, 2011
Creator: Texas. Legislature. House of Representatives.
Object Type: Legislative Document
System: The Portal to Texas History
Federal Register, Volume 76, Number 25, February 7, 2011, Pages 6523-6686 (open access)

Federal Register, Volume 76, Number 25, February 7, 2011, Pages 6523-6686

Daily publication of the U.S. Office of the Federal Register contains rules and regulations, proposed legislation and rule changes, and other notices, including "Presidential proclamations and Executive Orders, Federal agency documents having general applicability and legal effect, documents required to be published by act of Congress, and other Federal agency documents of public interest" (p. ii). Table of Contents starts on page iii.
Date: February 7, 2011
Creator: United States. Office of the Federal Register.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library