Qcd physics: measurement of the cross section for prompt diphoton production in p anti-p collisions at s**(1/2) = 1.96 tev (open access)

Qcd physics: measurement of the cross section for prompt diphoton production in p anti-p collisions at s**(1/2) = 1.96 tev

We report a measurement of the rate of prompt diphoton production in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample of 207 pb{sup -1} collected with the upgraded Collider Detector at Fermilab (CDF II). The background from non-prompt sources is determined using a statistical method based on differences in the electromagnetic showers. The cross section is measured as a function of the diphoton mass, the transverse momentum of the diphoton system, and the azimuthal angle between the two photons and is found to be consistent with perturbative QCD predictions.
Date: June 13, 2005
Creator: Acosta, D.
Object Type: Report
System: The UNT Digital Library
Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at {radical}(s{sub NN})=130 GeV (open access)

Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at {radical}(s{sub NN})=130 GeV

Mid-rapidity transverse mass spectra and multiplicity densities of charged and neutral kaons are reported for Au+Au collisions at {radical}s{sub NN}=130 GeV at RHIC. The spectra are exponential in transverse mass, with an inverse slope of about 280 MeV in central collisions. The multiplicity densities for these particles scale with the negative hadron pseudo-rapidity density. The charged kaon to pion ratios are K{sup +}/{pi}{sup -} = 0.161 {+-} 0.002(stat) {+-} 0.024(syst) and K{sup -}/{pi}{sup -} = 0.146 {+-} 0.002(stat) {+-} 0.022(syst) for the most central collisions. The K{sup +}/{pi}{sup -} ratio is lower than the same ratio observed at the SPS while the K{sup -}/{pi}{sup -} is higher than the SPS result. Both ratios are enhanced by about 50% relative to p+p and {bar p}+p collision data at similar energies.
Date: June 13, 2002
Creator: Adler, C.; Ahammed, Z.; Allgower, C.; Amonett, J.; Anderson, B. D.; Anderson, M. et al.
Object Type: Article
System: The UNT Digital Library
Mapping cis-Regulatory Domains in the Human Genome UsingMulti-Species Conservation of Synteny (open access)

Mapping cis-Regulatory Domains in the Human Genome UsingMulti-Species Conservation of Synteny

Our inability to associate distant regulatory elements with the genes that they regulate has largely precluded their examination for sequence alterations contributing to human disease. One major obstacle is the large genomic space surrounding targeted genes in which such elements could potentially reside. In order to delineate gene regulatory boundaries we used whole-genome human-mouse-chicken (HMC) and human-mouse-frog (HMF) multiple alignments to compile conserved blocks of synteny (CBS), under the hypothesis that these blocks have been kept intact throughout evolution at least in part by the requirement of regulatory elements to stay linked to the genes that they regulate. A total of 2,116 and 1,942 CBS>200 kb were assembled for HMC and HMF respectively, encompassing 1.53 and 0.86 Gb of human sequence. To support the existence of complex long-range regulatory domains within these CBS we analyzed the prevalence and distribution of chromosomal aberrations leading to position effects (disruption of a genes regulatory environment), observing a clear bias not only for mapping onto CBS but also for longer CBS size. Our results provide a genome wide data set characterizing the regulatory domains of genes and the conserved regulatory elements within them.
Date: June 13, 2005
Creator: Ahituv, Nadav; Prabhakar, Shyam; Poulin, Francis; Rubin, EdwardM. & Couronne, Olivier
Object Type: Article
System: The UNT Digital Library
Measurements of the asymmetric, dynamic sheath around a pulse biased sphere immersed in flowing metal plasma (open access)

Measurements of the asymmetric, dynamic sheath around a pulse biased sphere immersed in flowing metal plasma

A long-probe technique was utilized to record the expansion and retreat of the dynamic sheath around a spherical substrate immersed in pulsed cathode arc metal plasma. Positively biased, long cylindrical probes were placed on the side and downstream of a negatively pulsed biased stainless steel sphere of 1" (25.4 mm) diameter. The amplitude and width of the negative high voltage pulses (HVP) were 2 kV, 5 kV, 10 kV, and 2 mu s, 4 mu s, 10 mu s, respectively. The variation of the probe (electron) current during the HVP is a direct measure for the sheath expansion and retreat. Maximum sheath sizes were determined for the different parameters of the HVP. The expected rarefaction zone behind the biased sphere (wake) due to the fast plasma flow was clearly established and quantified.
Date: June 13, 2008
Creator: Anders, Andre; Wu, Hongchen & Anders, Andre
Object Type: Article
System: The UNT Digital Library
Radioactive Tank Waste from the Past Production of Nuclear Weapons: Background and Issues for Congress (open access)

Radioactive Tank Waste from the Past Production of Nuclear Weapons: Background and Issues for Congress

How to safely dispose of wastes from producing nuclear weapons has been an ongoing issue. The most radioactive portion of these wastes is stored in underground tanks at Department of Energy (DOE) sites in Idaho, South Carolina, and Washington State. There have been concerns about soil and groundwater contamination from some of the tanks that have leaked. This report provides background information on the disposal of radioactive tank waste, analyzes waste disposal authority in P.L. 108-375, and examines potential implications for environmental cleanup.
Date: June 13, 2006
Creator: Andrews, Anthony & Bearden, David M.
Object Type: Report
System: The UNT Digital Library
Measurement of the Auger Recombination Rate in p-type 0.54-eV GaInAsSb by Time-Resolved Photoluminescence (open access)

Measurement of the Auger Recombination Rate in p-type 0.54-eV GaInAsSb by Time-Resolved Photoluminescence

Auger recombination in p-type GaSb, InAs and their alloys is enhanced due to the proximity of the bandgap energy and the energy separation to the spin split-off valence band. This can affect the device performance even at moderate doping concentration. They report electron lifetime measurements in a p-type 0.54-eV GaInAsSb alloy, commonly used in a variety of infrared devices. They have studied a series of double-capped heterostructures with varied thicknesses and doping levels, grown by organometallic vapor phase epitaxy on GaSb substrates. The Auger coefficient value of 2.3 x 10{sup -28} cm{sup 6}/s is determined by analyzing the photoluminescence decay constants with a systematic separation of different recombination mechanisms.
Date: June 13, 2003
Creator: Anikeev, S.; Donetsky, D.; Belenky, G.; Luryi, S.; Wang, C.A.; Borrego, J.M. et al.
Object Type: Report
System: The UNT Digital Library
Search for the Decay B+ to Kbar*0(892) K+ (open access)

Search for the Decay B+ to Kbar*0(892) K+

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Date: June 13, 2007
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Multi-century Changes to Global Climate and Carbon Cycle: Results from a Coupled Climate and Carbon Cycle Model (open access)

Multi-century Changes to Global Climate and Carbon Cycle: Results from a Coupled Climate and Carbon Cycle Model

In this paper, we use a coupled climate and carbon cycle model to investigate the global climate and carbon cycle changes out to year 2300 that would occur if CO2 emissions from all the currently estimated fossil fuel resources were released to the atmosphere. By year 2300, the global climate warms by about 8 K and atmospheric CO2 reaches 1423 ppmv. In our simulation, the prescribed cumulative emission since pre-industrial period is about 5400 Gt-C by the end of 23rd century. At year 2300, nearly 45 % of cumulative emissions remain in the atmosphere. In our simulations both soils and living biomass are net carbon sinks throughout the simulation. Despite having relatively low climate sensitivity and strong carbon uptake by the land biosphere, our model projections suggest severe long-term consequences for global climate if all the fossil-fuel carbon is ultimately released to the atmosphere.
Date: June 13, 2005
Creator: Bala, G.; Caldeira, K.; Mirin, A.; Wickett, M. & Delire, C.
Object Type: Article
System: The UNT Digital Library
Automobile and Light Truck Fuel Economy: Is CAFE Up to Standards? (open access)

Automobile and Light Truck Fuel Economy: Is CAFE Up to Standards?

One of the least controversial provisions of the Energy Policy and Conservation Act of 1975 (P.L. 94-163) established corporate average fuel economy (CAFE) standards for new passenger cars. This report presents a brief background and analysis regarding the price of crude oil that brought into sharp focus the fuel inefficiency of U.S. automobiles. The report also discusses the previous issues and the most recent developments regarding CAFE.
Date: June 13, 2002
Creator: Bamberger, Robert L.
Object Type: Report
System: The UNT Digital Library
Energy Policy: The Continuing Debate (open access)

Energy Policy: The Continuing Debate

On April 11, 2003, the House passed comprehensive energy legislation, H.R. 6 (247-175).Action on comprehensive energy legislation is in progress in the Senate. The Senate Energy and Natural Resources Committee began markup of a comprehensive energy bill on April 7, 2003, agreeing by week’s end to provisions regarding hydrogen, hydroelectric relicensing, nuclear and renewable energy. On April 11, 2003, Chairman Domenici pulled a controversial section on climate change from the bill and indicated it would be addressed later.
Date: June 13, 2003
Creator: Bamberger, Robert L.
Object Type: Report
System: The UNT Digital Library
Laser Safety Inspection Criteria (open access)

Laser Safety Inspection Criteria

A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility …
Date: June 13, 2005
Creator: Barat, K.
Object Type: Article
System: The UNT Digital Library
Radiative b to d Penguins (open access)

Radiative b to d Penguins

This article gives an overview of the recent searches and measurements of b {yields} d penguin transitions with the BaBar experiment. The branching fraction of these decays in the Standard Model (SM) is expected to be a factor of 10 or more lower than the corresponding b {yields} s penguin transitions, but a deviation from the SM prediction would be an equally striking sign of new physics. The exclusive decay B {yields} {pi}{ell}{ell} is searched by BaBar with no excess over the background found. The BaBar measurement of B {yields} ({rho}, {omega}){gamma} provides the first evidence of B{sup +} {yields} {rho}{sup +}{gamma}, {sup c} is in good agreement with the previous Belle results and provides a measurement of |V{sub td}/V{sub ts}| independent of the one from Bs mixing. No deviation from the SM is found.
Date: June 13, 2007
Creator: Bechtle, P.
Object Type: Article
System: The UNT Digital Library
Physics Results from the National Spherical Torus Experiment (open access)

Physics Results from the National Spherical Torus Experiment

The National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory is designed for studying toroidal plasma confinement at very low aspect-ratio, A = R/a = 0.85m/0.68m {approximately} 1.25, with cross-section elongation up to 2.2 and triangularity up to 0.5, for plasma currents up to 1 MA and vacuum toroidal magnetic fields up to 0.6 T on axis. Conducting plates are installed close to the plasma on the outboard side to stabilize kink modes. This should permit operation with toroidal-{beta} approaching 40% [1]. The plasmas will be heated by up to 6 MW High-Harmonic Fast Waves (HHFW) at a frequency 30 MHz and by 5 MW of 80 keV deuterium Neutral Beam Injection. Inductive plasma startup can be supplemented by the process of Coaxial Helicity Injection (CHI).
Date: June 13, 2000
Creator: Bell, M. G.
Object Type: Article
System: The UNT Digital Library
Physics results from the National Spherical Torus Experiment (open access)

Physics results from the National Spherical Torus Experiment

The National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory is designed for studying toroidal plasma confinement at very low aspect-ratio, A=R/a = 0.85m/0.68m {approximately} 1.25, with cross-section elongation up to 2.2 and triangularity up to 0.5, for plasma currents up to 1 MA and vacuum toroidal magnetic fields up to 0.6 T on axis. Conducting plates are installed close to the plasma on the outboard side to stabilize kink modes. This should permit operation with toroidal-{beta} approaching 40%. The plasmas will be heated by up to 6 MW High-Harmonic Fast Waves (HHFW) at a frequency 30 MHz and by 5 MW of 80 keV deuterium Neutral Beam Injection. Inductive plasma startup can be supplemented by the process of Coaxial Helicity Injection (CHI).
Date: June 13, 2000
Creator: Bell, M.G.
Object Type: Report
System: The UNT Digital Library
The MESERAN Method: Rapid Quantification of Non-Volatile Organic Residue (NVOR) (open access)

The MESERAN Method: Rapid Quantification of Non-Volatile Organic Residue (NVOR)

The precision analytical technique known as MESERAN Analysis permits quantitative measurement of the level of preexisting nonvolatile organic residue (NVOR) on a substrate from <1 nanogram (ng)/cm{sup 2} to > 100 micrograms ({micro}g)/cm{sup 2} in 2 minutes. MESERAN Analysis is also applicable to determining NVOR in solvents and solvent extracts. The MESERAN method is able to quantify organic contamination levels down to and below 1 ng by depositing as little as 10 microliters ({micro}L) of solvent containing a known amount of contamination on a clean substrate, allowing it to evaporate, and measuring the evaporated residue. The method will be described in detail and NVOR measurements determined from MESERAN data will be presented.
Date: June 13, 2002
Creator: Benkovich, M.G.
Object Type: Article
System: The UNT Digital Library
Stability of High-Level Waste Forms (open access)

Stability of High-Level Waste Forms

The objective of the proposed effort is to use a new approach to develop solution models of complex waste glass systems and spent fuel that are predictive with regard to composition, phase separation, and volatility. The effort will also yield thermodynamic values for waste components that are fundamentally required for corrosion models used to predict the leaching/corrosion behavior for waste glass and spent fuel material. This basic information and understanding of chemical behavior can subsequently be used directly in computational models of leaching and transport in geologic media, in designing and engineering waste forms and barrier systems, and in prediction of chemical interactions.
Date: June 13, 2003
Creator: Besmann, Theodore M. & Vienna, John D.
Object Type: Report
System: The UNT Digital Library
Libya: Background and U.S. Relations (open access)

Libya: Background and U.S. Relations

On May 15, 2006, the Bush Administration announced its intention to restore full diplomatic relations with Libya and to rescind Libya's listing as a state sponsor of terrorism and a country not fully cooperating with U.S. counterterrorism efforts. The announcements mark the culmination of a period of improvement and rapprochement in U.S.-Libyan relations that begin in December 2003. Observers expect that these changes will usher in a new era in the U.S.-Libyan relationship, which has been strained and hostile for much of the last 35 years. This report provides background information on Libya and U.S.-Libyan relations; profile Libyan leader Muammar Al Qadhafi; discusses Libya's political and economic reform efforts; and reviews current issues of potential congressional interest.
Date: June 13, 2006
Creator: Blanchard, Christopher M.
Object Type: Report
System: The UNT Digital Library
Libya: Background and U.S. Relations (open access)

Libya: Background and U.S. Relations

This report provides background information on Libya and U.S.-Libyan relations; profiles Libyan leader Muammar al Qadhafi; discusses Libya’s political and economic reform efforts; and reviews current issues of potential congressional interest.
Date: June 13, 2006
Creator: Blanchard, Christopher M.
Object Type: Report
System: The UNT Digital Library
Statement of Basis/Proposed Plan for the P-Area Burning Rubble Pit (131-P) (open access)

Statement of Basis/Proposed Plan for the P-Area Burning Rubble Pit (131-P)

The Statement of Basis/Proposed Plan (SB/PP) is being issued by the United States Department of Energy (USDOE), which functions as the lead agency for Savannah River Site (SRS) remedial activities, with concurrence by the United States Environmental Protection Agency (USEPA) and the South Carolina Department of Health and Environmental Control (SCDHEC). The purpose of this SB/PP is to describe the preferred remedial alternatives for the P-Area Burning/Rubble Pit (131-P) (PBRP) Operable Unit (OU) and to provide for public involvement in the decision-making process.
Date: June 13, 2002
Creator: Bland, T.
Object Type: Report
System: The UNT Digital Library
Development and Characterization of a Single Line of Sight Framing Camera (open access)

Development and Characterization of a Single Line of Sight Framing Camera

We present initial characterization data from a new single line of sight (SLOS) x-ray framing camera. The instrument uses an image dissecting structure inside an electron optic tube to produce up to four simultaneous DC images from a single image incident on the cathode and a microchannel plate based device to provide the temporal gating of those images. A series of gated images have been obtained using a short pulse UV laser source, and the spatial resolution of those images is compared to those obtained using a more traditional MCP based system.
Date: June 13, 2000
Creator: Bradley, D K; Bell, P M; Dymoke-Bradshaw, A K L; Hares, J D; Bahr, R E & Smalyuk, V A
Object Type: Article
System: The UNT Digital Library
Photometric Redshifts in the IRAC Shallow Survey (open access)

Photometric Redshifts in the IRAC Shallow Survey

Accurate photometric redshifts are calculated for nearly 200,000 galaxies to a 4.5 micron flux limit of {approx} 13 {micro}Jy in the 8.5 deg{sup 2} Spitzer/IRAC Shallow survey. Using a hybrid photometric redshift algorithm incorporating both neural-net and template-fitting techniques, calibrated with over 15,000 spectroscopic redshifts, a redshift accuracy of {sigma} = 0.06 (1+z) is achieved for 95% of galaxies at 0 < z < 1.5. The accuracy is {sigma} = 0.12 (1 + z) for 95% of AGN at 0 < z < 3. Redshift probability functions, central to several ongoing studies of the galaxy population, are computed for the full sample. We demonstrate that these functions accurately represent the true redshift probability density, allowing the calculation of valid confidence intervals for all objects. These probability functions have already been used to successfully identify a population of Spitzer-selected high redshift (z > 1) galaxy clusters. We present one such spectroscopically confirmed cluster at <z> = 1.24, ISCS J1434.2+3426. Finally, we present a measurement of the 4.5 {micro}m-selected galaxy redshift distribution.
Date: June 13, 2006
Creator: Brodwin, M.; Brown, M.; Ashby, M.; Bian, C.; Brand, K.; Dey, A. et al.
Object Type: Article
System: The UNT Digital Library
A brief review of the intensity of lines 3C and 3D in neon-like Fe XVII (open access)

A brief review of the intensity of lines 3C and 3D in neon-like Fe XVII

X-ray emission from neon-like Fe XVII has been measured with high-resolution spectrometers from laboratory or celestial sources for nearly seven decades. Two of the strongest lines regularly identified in these spectra are the {sup 1}P{sub 1} {yields} {sup 1}S{sub 0} resonance, and {sup 3}D{sub 1} {yields} {sup 1}S{sub 0} intercombination line, known as 3C and 3D, respectively. This paper gives a brief overview of measurements of the intensities of the lines 3C and 3D from laboratory and celestial sources, and their comparison to model calculations, with an emphasis on measurements completed using an electron beam ion trap. It includes a discussion of the measured absolute cross sections compared to results from modern atomic theory calculations, as well as the diagnostic utility of the relative intensity, R = I{sub 3C}/I{sub 3D}, as it applies to the interpretation of spectra measured from the Sun and extra-Solar sources.
Date: June 13, 2007
Creator: Brown, G V
Object Type: Article
System: The UNT Digital Library
Fishery, Aquaculture, and Marine Mammal Legislation in the 107th Congress (open access)

Fishery, Aquaculture, and Marine Mammal Legislation in the 107th Congress

This report presents the information related to the fishery, aquaculture, and marine mammal legislation enacted by the 107th congress
Date: June 13, 2002
Creator: Buck, Eugene H.
Object Type: Report
System: The UNT Digital Library
Fishery, Aquaculture, and Marine Mammal Legislation in the 110th Congress (open access)

Fishery, Aquaculture, and Marine Mammal Legislation in the 110th Congress

Aquaculture — the farming of fish, shellfish, and other aquatic animals and plants in a controlled environment — is expanding rapidly abroad, with more modest advances in the United States. This report discusses the federal laws and regulations that guide the management of resources in open ocean and near-shore coastal areas.
Date: June 13, 2008
Creator: Buck, Eugene H.
Object Type: Report
System: The UNT Digital Library