Measurement of the production fraction times branching fraction $\boldsymbol{ f(b\to\Lambda_{b})\cdot \mathcal{B}(\Lambda_{b}\to J/\psi \Lambda)}$ (open access)

Measurement of the production fraction times branching fraction $\boldsymbol{ f(b\to\Lambda_{b})\cdot \mathcal{B}(\Lambda_{b}\to J/\psi \Lambda)}$

The {Lambda}{sub b}(udb) baryon is observed in the decay {Lambda}{sub b} {yields} J/{psi}{Lambda} using 6.1 fb{sup -1} of p{bar p} collisions collected with the D0 detector at {radical}s = 1.96 TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay B{sup 0} {yields} J/{psi}K{sub s}{sup 0} is measured to be 0.345 {+-} 0.034 (stat.) {+-} 0.033 (syst.) {+-} 0.003 (PDG). Using the world average value of f(b {yields} B{sup 0}) {center_dot} {Beta}(B{sup 0} {yields} J/{psi}K{sub s}{sup 0}) = (1.74 {+-} 0.08) x 10{sup -5}, they obtain f(b {yields} {Lambda}{sub b}) {center_dot} {Beta}({Lambda}{sub b} {yields} J/{psi}{Lambda}) = (6.01 {+-} 0.60 (stat.) {+-} 0.58 (syst.) {+-} 0.28 (PDG)) x 10{sup -5}. This measurement represents an improvement in precision by about a factor of three with respect to the current world average.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the $t\bar{t}$ production cross section using dilepton events in $p\bar{p}$ collisions (open access)

Measurement of the $t\bar{t}$ production cross section using dilepton events in $p\bar{p}$ collisions

We present a measurement of the t{bar t} production cross section {sigma}{sub t{bar t}} in p{bar p} collisions at {radical}s = 1.96 TeV using 5.4 fb{sup -1} of integrated luminosity collected with the D0 detector. We consider final states with at least two jets and two leptons (ee, e{mu}, {mu}{mu}), and events with one jet for the the e{mu} final state as well. The measured cross section is {sigma}{sub t{bar t}} = 7.36{sub -0.79}{sup +0.90} (stat + syst) pb. This result combined with the cross section measurement in the lepton + jets final state yields {sigma}{sub t{bar t}} = 7.56{sub -0.56}{sup +0.63}(stat + syst) pb, which agrees with the standard model expectation. The relative precision of 8% of this measurement is comparable to the latest theoretical calculations.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Model-independent measurement of $\boldsymbol{t}$-channel single top quark production in $\boldsymbol{p\bar{p}}$ collisions at $\boldsymbol{\sqrt{s}=1.96}$ TeV (open access)

Model-independent measurement of $\boldsymbol{t}$-channel single top quark production in $\boldsymbol{p\bar{p}}$ collisions at $\boldsymbol{\sqrt{s}=1.96}$ TeV

We present a model-independent measurement of t-channel electroweak production of single top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. Using 5.4 fb{sup -1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider, and selecting events containing an isolated electron or muon, missing transverse energy and one or two jets originating from the fragmentation of b quarks, we measure a cross section {sigma}(p{bar p} {yields} tqb + X) = 2.90 {+-} 0.59 (stat + syst) pb for a top quark mass of 172.5 GeV. The probability of the background to fluctuate and produce a signal as large as the one observed is 1.6 x 10{sup -8}, corresponding to a significance of 5.5 standard deviations.
Date: May 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Taming transport in InN (open access)

Taming transport in InN

The large electron affinity of InN, close to 6 eV and the largest of any III-V semiconductor, creates a strong driving force for native donor formation, both in the bulk and at surfaces and interfaces. Moreover, all InN surfaces, regardless of crystal orientation or doping, have been observed to have a surface accumulation layer of electrons, which interferes with standard electrical measurements. For these reasons, until recently, it was uncertain whether or not compensation by donor defects would prevent “real” p-type activity (i.e. existence of sufficiently shallow acceptors and mobile holes). A coordinated experimental approach using a combination of electrical (Hall effect) and electrothermal (Seebeck coefficient) measurements will be described that allows definitive evaluation of carrier transport in InN. In Mg-doped InN films, the sensitivity of thermopower to bulk hole conduction, combined with modeling of the parallel conducting layers (surface/bulk/interface), enables quantitative measurement of the free hole concentration and mobility. In undoped (n-type) material, combined Hall and thermopower measurements, along with a considering of the scattering mechanisms, leads to a quantitative understanding of the crucial role of charged line defects in limiting electron transport.
Date: May 29, 2011
Creator: Ager, Joel W., III & Miller, Nate R.
Object Type: Article
System: The UNT Digital Library
Biological Interactions and Dynamics Science Theme Advisory Panel (BID-STAP) (open access)

Biological Interactions and Dynamics Science Theme Advisory Panel (BID-STAP)

This report contains the charge to the panel, the panel's discussions and panel recommendations.
Date: May 1, 2011
Creator: Ahring, Birgitte K.; Baliga, Nitin S.; Frederickson, James R.; Kaplan, Samuel; Pakrasi, Himadri B.; Pounds, Joel G. et al.
Object Type: Report
System: The UNT Digital Library
Using Cool Roofs to Reduce Energy Use, Greenhouse Gas Emissions, and Urban Heat-island Effects: Findings from an India Experiment (open access)

Using Cool Roofs to Reduce Energy Use, Greenhouse Gas Emissions, and Urban Heat-island Effects: Findings from an India Experiment

Cool roofs, cool pavements, and urban vegetation reduce energy use in buildings, lower local air pollutant concentrations, and decrease greenhouse gas emissions from urban areas. This report summarizes the results of a detailed monitoring project in India and related simulations of meteorology and air quality in three developing countries. The field results quantified direct energy savings from installation of cool roofs on individual commercial buildings. The measured annual energy savings potential from roof-whitening of previously black roofs ranged from 20-22 kWh/m2 of roof area, corresponding to an air-conditioning energy use reduction of 14-26% in commercial buildings. The study estimated that typical annual savings of 13-14 kWh/m2 of roof area could be achieved by applying white coating to uncoated concrete roofs on commercial buildings in the Metropolitan Hyderabad region, corresponding to cooling energy savings of 10-19%. With the assumption of an annual increase of 100,000 square meters of new roof construction for the next 10 years in the Metropolitan Hyderabad region, the annual cooling energy savings due to whitening concrete roof would be 13-14 GWh of electricity in year ten alone, with cumulative 10-year cooling energy savings of 73-79 GWh for the region. The estimated savings for the entire country would …
Date: May 25, 2011
Creator: Akbari, Hashem; Xu, Tengfang; Taha, Haider; Wray, Craig; Sathaye, Jayant; Garg, Vishal et al.
Object Type: Report
System: The UNT Digital Library
A Regional Seismic Array of Three-Component Stations in Central Saudi Arabia (open access)

A Regional Seismic Array of Three-Component Stations in Central Saudi Arabia

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Date: May 4, 2011
Creator: Al-Amri, A.; Harris, D.; Fnais, M.; Rodgers, A. & Hemaida, M.
Object Type: Article
System: The UNT Digital Library
Development of a micro flow-through cell for high field NMR spectroscopy. (open access)

Development of a micro flow-through cell for high field NMR spectroscopy.

A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.
Date: May 1, 2011
Creator: Alam, Todd Michael & McIntyre, Sarah K.
Object Type: Report
System: The UNT Digital Library
CdTe Feedstock Development and Validation: Cooperative Research and Development Final Report, CRADA Number CRD-08-00280 (open access)

CdTe Feedstock Development and Validation: Cooperative Research and Development Final Report, CRADA Number CRD-08-00280

The goal of this work was to evaluate different CdTe feedstock formulations (feedstock provided by Redlen) to determine if they would significantly improve CdTe performance with ancillary benefits associated with whether changes in feedstock would affect CdTe cell processing and possibly reliability of cells. Feedstock also included attempts to intentionally dope the CdTe with pre-selected elements.
Date: May 1, 2011
Creator: Albin, D.
Object Type: Report
System: The UNT Digital Library
CP Violation in D0-D0bar Mixing and Electric Dipole Moments in SUSY Alignment Models (open access)

CP Violation in D0-D0bar Mixing and Electric Dipole Moments in SUSY Alignment Models

We report on a study of CP Violation in D{sup 0}-{bar D}{sup 0} mixing and Electric Dipole Moments in the framework of supersymmetric alignment models. Both classes of observables are strongly suppressed in the Standard Model and highly sensitive to new sources of flavor and CP violation that can be present in models of New Physics. Supersymmetric alignment models generically predict large non-standard effects in D{sup 0}-{bar D}{sup 0} mixing and we show that visible CP violation in D{sup 0}-{bar D}{sup 0} mixing implies lower bounds for the EDMs of hadronic systems, like the neutron EDM and the mercury EDM, in the reach of future experimental sensitivities. We also give updated constraints on the mass insertions of the Minimal Supersymmetric Standard Model using the current data on D{sup 0}-{bar D}{sup 0} mixing.
Date: May 1, 2011
Creator: Altmannshofer, Wolfgang
Object Type: Article
System: The UNT Digital Library
Advanced High-Speed Framing Camera Development for Fast, Visible Imaging Experiments (open access)

Advanced High-Speed Framing Camera Development for Fast, Visible Imaging Experiments

The advances in high-voltage switching developed in this project allow a camera user to rapidly vary the number of output frames from 1 to 25. A high-voltage, variable-amplitude pulse train shifts the deflection location to the new frame location during the interlude between frames, making multiple frame counts and locations possible. The final deflection circuit deflects to five different frame positions per axis, including the center position, making for a total of 25 frames. To create the preset voltages, electronically adjustable {+-}500 V power supplies were chosen. Digital-to-analog converters provide digital control of the supplies. The power supplies are clamped to {+-}400 V so as not to exceed the voltage ratings of the transistors. A field-programmable gated array (FPGA) receives the trigger signal and calculates the combination of plate voltages for each frame. The interframe time and number of frames are specified by the user, but are limited by the camera electronics. The variable-frame circuit shifts the plate voltages of the first frame to those of the second frame during the user-specified interframe time. Designed around an electrostatic image tube, a framing camera images the light present during each frame (at the photocathode) onto the tube’s phosphor. The phosphor persistence …
Date: May 11, 2011
Creator: Amy Lewis, Stuart Baker, Brian Cox, Abel Diaz, David Glass, Matthew Martin
Object Type: Article
System: The UNT Digital Library
Novel Insights into the Diversity of Catabolic Metabolism from Ten Haloarchaeal Genomes (open access)

Novel Insights into the Diversity of Catabolic Metabolism from Ten Haloarchaeal Genomes

The extremely halophilic archaea are present worldwide in saline environments and have important biotechnological applications. Ten complete genomes of haloarchaea are now available, providing an opportunity for comparative analysis. We report here the comparative analysis of five newly sequenced haloarchaeal genomes with five previously published ones. Whole genome trees based on protein sequences provide strong support for deep relationships between the ten organisms. Using a soft clustering approach, we identified 887 protein clusters present in all halophiles. Of these core clusters, 112 are not found in any other archaea and therefore constitute the haloarchaeal signature. Four of the halophiles were isolated from water, and four were isolated from soil or sediment. Although there are few habitat-specific clusters, the soil/sediment halophiles tend to have greater capacity for polysaccharide degradation, siderophore synthesis, and cell wall modification. Halorhabdus utahensis and Haloterrigena turkmenica encode over forty glycosyl hydrolases each, and may be capable of breaking down naturally occurring complex carbohydrates. H. utahensis is specialized for growth on carbohydrates and has few amino acid degradation pathways. It uses the non-oxidative pentose phosphate pathway instead of the oxidative pathway, giving it more flexibility in the metabolism of pentoses. These new genomes expand our understanding of haloarchaeal …
Date: May 3, 2011
Creator: Anderson, Iain; Scheuner, Carmen; Goker, Markus; Mavromatis, Kostas; Hooper, Sean D.; Porat, Iris et al.
Object Type: Article
System: The UNT Digital Library
Nuclear Power Plant Design and Seismic Safety Considerations (open access)

Nuclear Power Plant Design and Seismic Safety Considerations

This report presents some of the general design concepts of operating nuclear power plants in order to discuss design considerations for seismic events. This report does not attempt to conclude whether one design is inherently safer or less safe than another plant. Nor does it attempt to conclude whether operating nuclear power plants are at any greater or lesser risk from earthquakes given recent updates to seismic data and seismic hazard maps.
Date: May 2, 2011
Creator: Andrews, Anthony
Object Type: Report
System: The UNT Digital Library
Assessment of the Economic Potential of Microgrids for Reactive Power Supply (open access)

Assessment of the Economic Potential of Microgrids for Reactive Power Supply

As power generation from variable distributed energy resources (DER) grows, energy flows in the network are changing, increasing the requirements for ancillary services, including voltage support. With the appropriate power converter, DER can provide ancillary services such as frequency control and voltage support. This paper outlines the economic potential of DERs coordinated in a microgrid to provide reactive power and voltage support at its point of common coupling. The DER Customer Adoption Model assesses the costs of providing reactive power, given local utility rules. Depending on the installed DER, the cost minimizing solution for supplying reactive power locally is chosen. Costs include the variable cost of the additional losses and the investment cost of appropriately over-sizing converters or purchasing capacitors. A case study of a large health care building in San Francisco is used to evaluate different revenue possibilities of creating an incentive for microgrids to provide reactive power.
Date: May 1, 2011
Creator: Appen, Jan von; Marnay, Chris; Stadler, Michael; Momber, Ilan; Klapp, David & Scheven, Alexander von
Object Type: Article
System: The UNT Digital Library
U.S.-EU Cooperation Against Terrorism (open access)

U.S.-EU Cooperation Against Terrorism

The September 11, 2001, terrorist attacks gave new momentum to European Union (EU) initiatives to combat terrorism and improve police, judicial, and intelligence cooperation among its member states. Since the 2001 attacks, the EU has sought to speed up its efforts to harmonize national laws and bring down barriers among member states' law enforcement authorities so that information can be meaningfully shared and suspects apprehended expeditiously. Among other steps, the EU has established a common definition of terrorism and a common list of terrorist groups, an EU arrest warrant, enhanced tools to stem terrorist financing, and new measures to strengthen external EU border controls and improve aviation security.
Date: May 2, 2011
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
The European Union: Questions and Answers (open access)

The European Union: Questions and Answers

This report provides a brief overview of the European Union (EU), an economic and political partnership between 27 sovereign member states. The report describes the formation of the EU, the three main institutions of the EU, and the EU's relationship with the United States.
Date: May 4, 2011
Creator: Archick, Kristin & Mix, Derek E.
Object Type: Report
System: The UNT Digital Library
Morocco: Current Issues (open access)

Morocco: Current Issues

This report discusses the current political and foreign policy status of Morocco, especially with regard to its relationship with the United States and its struggles combating terrorism.
Date: May 27, 2011
Creator: Arieff, Alexis
Object Type: Report
System: The UNT Digital Library
U.S. Foreign Assistance to Sub-Saharan Africa: The FY2012 Request (open access)

U.S. Foreign Assistance to Sub-Saharan Africa: The FY2012 Request

Sub-Saharan Africa, the world's poorest region, receives over a quarter of all U.S. bilateral foreign assistance. Aid to Africa more than quadrupled over the past decade, primarily due to sizable increases in global health spending during the Bush Administration and more measured increases in development, economic, and security assistance. The Obama Administration's FY2012 bilateral Africa aid budget request, at $7.8 billion, represents an increase of roughly 10% compared to FY2010, albeit at a more restrained growth rate than in previous years (see "The FY2012 Request by the Numbers"). FY2011 enacted levels are not yet available by region. The proposed increases are concentrated in the areas of health, governance, and agriculture.
Date: May 20, 2011
Creator: Arieff, Alexis; Cook, Nicolas; Salaam-Blyther, Tiaji; Kendall, Alexandra E.; Tarnoff, Curt & Ho, Melissa D.
Object Type: Report
System: The UNT Digital Library
Summary for Policy Makers: Intergovernmental Panel on Climate Change Special Report Renewable Energy Sources (SRREN) (open access)

Summary for Policy Makers: Intergovernmental Panel on Climate Change Special Report Renewable Energy Sources (SRREN)

The Working Group III Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) presents an assessment of the literature on the scientific, technological, environmental, economic and social aspects of the contribution of six renewable energy (RE) sources to the mitigation of climate change. It is intended to provide policy relevant information to governments, intergovernmental processes and other interested parties. This Summary for Policymakers provides an overview of the SRREN, summarizing the essential findings. The SRREN consists of 11 chapters. Chapter 1 sets the context for RE and climate change; Chapters 2 through 7 provide information on six RE technologies, and Chapters 8 through 11 address integrative issues.
Date: May 8, 2011
Creator: Arvizu, Dan; Bruckner, Thomas; Christensen, John; Devernay, Jean-Michel; Faaij , Andre; Fischedick, Manfred et al.
Object Type: Article
System: The UNT Digital Library
Opportunities for Drell-Yan Physics at RHIC (open access)

Opportunities for Drell-Yan Physics at RHIC

Drell-Yan (DY) physics gives the unique opportunity to study the parton structure of nucleons in an experimentally and theoretically clean way. With the availability of polarized proton-proton collisions and asymmetric d+Au collisions at the Relativistic Heavy Ion Collider (RHIC), we have the basic (and unique in the world) tools to address several fundamental questions in QCD, including the expected gluon saturation at low partonic momenta and the universality of transverse momentum dependent parton distribution functions. A Drell-Yan program at RHIC is tied closely to the core physics questions of a possible future electron-ion collider, eRHIC. The more than 80 participants of this workshop focused on recent progress in these areas by both theory and experiment, trying to address imminent questions for the near and mid-term future.
Date: May 24, 2011
Creator: Aschenauer, E.; Bland, L.; Crawford, H.; Goto, Y.; Eyser, O.; Kang, Z. et al.
Object Type: Report
System: The UNT Digital Library
The Debt Limit: History and Recent Increases (open access)

The Debt Limit: History and Recent Increases

This report gives an overview of the federal debt limit, its history, and recent increases
Date: May 10, 2011
Creator: Austin, D. Andrew
Object Type: Report
System: The UNT Digital Library
Overview of the Federal Debt (open access)

Overview of the Federal Debt

The size of current and projected federal deficits and the accumulation of federal debt are central to current congressional deliberations regarding fiscal reforms. This report provides a broad overview of the federal debt, annual budget deficits, and debt service costs. Federal debt is the accumulated sum of unrepaid borrowing by the federal government over time. The total federal debt consists of debt held by the public and intragovernmental debt. Debt owed to the public represents borrowing from entities other than the federal government, and includes borrowing from state and local governments, foreign governments and investors, the Federal Reserve System, and foreign central banks, as well as private investors in the United States.
Date: May 22, 2011
Creator: Austin, D. Andrew
Object Type: Report
System: The UNT Digital Library
The Debt Limit: History and Recent Increases (open access)

The Debt Limit: History and Recent Increases

This report discusses how the total debt of the federal government can increase, an historical overview of debt limits, and how the current economic slowdown has led to higher deficits and thereby a series of debt limit increases, as well as legislation related to these increases.
Date: May 2, 2011
Creator: Austin, D. Andrew & Levit, Mindy R.
Object Type: Report
System: The UNT Digital Library
The Debt Limit: History and Recent Increases (open access)

The Debt Limit: History and Recent Increases

This report discusses how the total debt of the federal government can increase, an historical overview of debt limits, and how the current economic slowdown has led to higher deficits and thereby a series of debt limit increases, as well as legislation related to these increases.
Date: May 16, 2011
Creator: Austin, D. Andrew & Levit, Mindy R.
Object Type: Report
System: The UNT Digital Library