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Mexico’s Drug Trafficking Organizations: Source and Scope of the Violence
This report details drug trafficking in Mexico and how it has altered. It also delves into the violence of the drug organizations, and depicts possible ways to reduce the violence.
Date:
April 15, 2013
Creator:
Beittel, June S.
Object Type:
Report
System:
The UNT Digital Library
Government Shutdown: Operations of the Department of Defense During a Lapse in Appropriations
This report provides an overview of guidelines that have governed planning for Department of Defense (DOD) operations over the last 30 years in the event of a funding lapse. It also discusses the implications of the guidelines for a possible impending shutdown and briefly reviews what is known about current DOD planning for a shutdown.
Date:
October 15, 2013
Creator:
Belasco, Amy & Towell, Pat
Object Type:
Report
System:
The UNT Digital Library
Holocaust-Era Insurance Claims: Background and Proposed Legislation
This report aims to inform consideration of H.R. 890 and S. 466 and possible alternatives by providing; background on Holocaust-era compensation and restitution issues; an overview of ICHEIC, including criticism and support of its claims process and Administration policy on ICHEIC; and an overview of litigation on Holocaust-era insurance claims and the proposed legislation.
Date:
June 15, 2012
Creator:
Belkin, Paul; Ruane, Kathleen Ann & Webel, Baird
Object Type:
Report
System:
The UNT Digital Library
Newsletter of Texas State Representative Cecil Bell, Jr.: October 2013
Newsletter of Cecil Bell, Jr. for his constituents in district 3 discussing news, activities, and various updates related to work in the Texas legislature. It focuses on an upcoming Texas Constitutional Amendment Election.
Date:
October 15, 2015
Creator:
Bell, Cecil Ivan, Jr.
Object Type:
Journal/Magazine/Newsletter
System:
The Portal to Texas History
Genetic manipulation of the obligate chemolithoautotrophic bacterium Thiobacillus denitrificans
Chemolithoautotrophic bacteria can be of industrial and environmental importance, but they present a challenge for systems biology studies, as their central metabolism deviates from that of model organisms and there is a much less extensive experimental basis for their gene annotation than for typical organoheterotrophs. For microbes with sequenced genomes but unconventional metabolism, the ability to create knockout mutations can be a powerful tool for functional genomics and thereby render an organism more amenable to systems biology approaches. In this chapter, we describe a genetic system for Thiobacillus denitrificans, with which insertion mutations can be introduced by homologous recombination and complemented in trans. Insertion mutations are generated by in vitro transposition, the mutated genes are amplified by the PCR, and the amplicons are introduced into T. denitrificans by electroporation. Use of a complementation vector, pTL2, based on the IncP plasmid pRR10 is also addressed.
Date:
July 15, 2011
Creator:
Beller, H.R.; Legler, T.C. & Kane, S.R.
Object Type:
Article
System:
The UNT Digital Library
Navajo-Hopi Land Commission Renewable Energy Development Project (NREP)
The Navajo Hopi Land Commission Office (NHLCO), a Navajo Nation executive branch agency has conducted activities to determine capacity-building, institution-building, outreach and management activities to initiate the development of large-scale renewable energy - 100 megawatt (MW) or larger - generating projects on land in Northwestern New Mexico in the first year of a multi-year program. The Navajo Hopi Land Commission Renewable Energy Development Project (NREP) is a one year program that will develop and market a strategic business plan; form multi-agency and public-private project partnerships; compile site-specific solar, wind and infrastructure data; and develop and use project communication and marketing tools to support outreach efforts targeting the public, vendors, investors and government audiences.
Date:
May 15, 2012
Creator:
Benally, Thomas
Object Type:
Report
System:
The UNT Digital Library
Measurement of the D_s Decay Constant f_Ds and Observation of New Charm Resonances Decaying to D^(*)\pi
The absolute branching fractions for the decays D{sub s}{sup -} {yields} {ell}{sup -}{bar {nu}}{sub {ell}} ({ell} = e, {mu}, or {tau}) are measured using a data sample corresponding to an integrated luminosity of 521 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEPII e{sup +}e{sup -} collider at SLAC. The number of D{sub s}{sup -} mesons is determined by reconstructing the recoiling system DKX{gamma} in events of the type e{sup +}e{sup -} {yields} DKXD*{sub s}{sup -}, where D*{sub s}{sup -} {yields} D{sub s}{sup -} {gamma} and X represents additional pions from fragmentation. The D{sub s}{sup -} {yields} {ell}{sup -}{nu}{sub {ell}} events are detected by full or partial reconstruction of the recoiling system DKX{gamma}{ell}. The following results are obtained: {Beta}(D{sub s}{sup -} {yields} {mu}{sup -}{nu}) = (6.02 {+-} 0.38 {+-} 0.34) x 10{sup -3}, {Beta}(D{sub s}{sup -} {yields} {tau}{sup -}{nu}) = (5.00 {+-} 0.35 {+-} 0.49) x 10{sup -2}, and B(D{sub s}{sup -} {yields} e{sup -}{nu}) < 2.8 x 10{sup -4} at 90% C.L., where the first uncertainty is statistical and the second is systematic. The branching fraction measurements are combined to determine the D{sub s}{sup -} decay constant f{sub D{sub s}} …
Date:
March 15, 2012
Creator:
Benitez, Jose
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
NLO Jet Physics with BlackHat
We present several results obtained using the BLACKHAT next-to-leading order QCD program library, in conjunction with SHERPA. In particular, we present distributions for vector boson plus 1,2,3-jet production at the Tevatron and at the asymptotic running energy of the Large Hadron Collider, including new Z + 3-jet distributions. The Z + 2-jet predictions for the second-jet P{sub T} distribution are compared to CDF data. We present the jet-emission probability at NLO in W + 2-jet events at the LHC, where the tagging jets are taken to be the ones furthest apart in pseudorapidity. We analyze further the large left-handed W{sup {+-}} polarization, identified in our previous study, for W bosons produced at high P{sub T} at the LHC.
Date:
February 15, 2010
Creator:
Berger, C. F.; Bern, Z.; Dixon, L. J.; Cordero, F. Febres; Forde, D.; Gleisberg, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Review of the Oak Ridge National Laboratory (ORNL) neutronic calculations regarding the conversion of the high flux isotope reactor (HFIR) to the use of low enriched uranium (LEU) fuel
None
Date:
January 15, 2013
Creator:
Bergeron, A. (Nuclear Engineering Division)
Object Type:
Report
System:
The UNT Digital Library
Simplifying Multi-loop Integrands of Gauge Theory and Gravity Amplitudes
We use the duality between color and kinematics to simplify the construction of the complete four-loop four-point amplitude of N = 4 super-Yang-Mills theory, including the nonplanar contributions. The duality completely determines the amplitude's integrand in terms of just two planar graphs. The existence of a manifestly dual gauge-theory amplitude trivializes the construction of the corresponding N = 8 supergravity integrand, whose graph numerators are double copies (squares) of the N = 4 super-Yang-Mills numerators. The success of this procedure provides further nontrivial evidence that the duality and double-copy properties hold at loop level. The new form of the four-loop four-point supergravity amplitude makes manifest the same ultraviolet power counting as the corresponding N = 4 super-Yang-Mills amplitude. We determine the amplitude's ultraviolet pole in the critical dimension of D = 11/2, the same dimension as for N = 4 super-Yang-Mills theory. Strikingly, exactly the same combination of vacuum integrals (after simplification) describes the ultraviolet divergence of N = 8 supergravity as the subleading-in-1/N{sub c}{sup 2} single-trace divergence in N = 4 super-Yang-Mills theory.
Date:
February 15, 2012
Creator:
Bern, Z.; Carrasco, J.J.M.; Dixon, L.J.; Johansson, H. & Roiban, R.
Object Type:
Article
System:
The UNT Digital Library
NLO Vector Boson Production With Light Jets
In this contribution we present recent progress in the computation of next-to-leading order (NLO) QCD corrections for the production of an electroweak vector boson in association with jets at hadron colliders. We focus on results obtained using the virtual matrix element library BlackHat in conjunction with SHERPA, focusing on results relevant to understanding the background to top production. The production of a vector boson in association with several jets at the Large Hadron Collider (LHC) is an important background for other Standard Model processes as well as new physics signals. In particular, the production of a W boson in association with many jets is an important background for processes involving one or more top quarks. Precise predictions for the backgrounds are crucial to measurement of top-quark processes. Vector boson production in association with multiple jets is also a very important background for many SUSY searches, as it mimics the signatures of many typical decay chains. Here we will discuss how polarization information can be used as an additional handle to differentiate top pair production from 'prompt' W-boson production. More generally, ratios of observables, for example for events containing a W boson versus those containing a Z boson, are expected to …
Date:
February 15, 2012
Creator:
Bern, Z.; Diana, G.; Dixon, L.J.; Febres Cordero, F.; Forde, D.; Gleisberg, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Orbitronics: the Intrinsic Orbital Hall Effect in p-Doped Silicon
The spin Hall effect depends crucially on the intrinsic spin-orbit coupling of the energy band. Because of the smaller spin-orbit coupling in silicon, the spin Hall effect is expected to be much reduced. We show that the electric field in p-doped silicon can induce a dissipationless orbital current in a fashion reminiscent of the spin Hall effect. The vertex correction due to impurity scattering vanishes and the effect is therefore robust against disorder. The orbital Hall effect can lead to the accumulation of local orbital momentum at the edge of the sample, and can be detected by the Kerr effect.
Date:
January 15, 2010
Creator:
Bernevig, B.Andrei; Hughes, Taylor L.; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type:
Article
System:
The UNT Digital Library
Maxwell Equation for the Coupled Spin-Charge Wave Propagation
We show that the dissipationless spin current in the ground state of the Rashba model gives rise to a reactive coupling between the spin and charge propagation, which is formally identical to the coupling between the electric and the magnetic fields in the 2 + 1 dimensional Maxwell equation. This analogy leads to a remarkable prediction that a density packet can spontaneously split into two counter propagation packets, each carrying the opposite spins. In a certain parameter regime, the coupled spin and charge wave propagates like a transverse 'photon'. We propose both optical and purely electronic experiments to detect this effect.
Date:
January 15, 2010
Creator:
Bernevig, B.Andrei; Yu, Xiaowei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type:
Article
System:
The UNT Digital Library
Intrinsic Spin-Hall Effect in n-Doped Bulk GaAs
We show that the bulk Dresselhauss (k{sup 3}) spin-orbit coupling term leads to an intrinsic spin-Hall effect in n-doped bulk GaAs, but without the appearance of uniform magnetization. The spin-Hall effect in strained and unstrained bulk GaAs has been recently observed experimentally by Kato et. al. [1]. We show that the experimental result is quantitatively consistent with the intrinsic spin-Hall effect due to the Dresselhauss term, when lifetime broadening is taken into account. On the other hand, extrinsic contribution to the spin-Hall effect is several orders of magnitude smaller than the observed effect.
Date:
January 15, 2010
Creator:
Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type:
Report
System:
The UNT Digital Library
Intrinsic Spin Hall Effect in the Two Dimensional Hole Gas
We show that two types of spin-orbit coupling in the 2 dimensional hole gas (2DHG), with and without inversion symmetry breaking, contribute to the intrinsic spin Hall effect. Furthermore, the vertex correction due to impurity scattering vanishes in both cases, in sharp contrast to the case of usual Rashba coupling in the electron band. Recently, the spin Hall effect in a hole doped GaAs semiconductor has been observed experimentally by Wunderlich et al. From the fact that the life time broadening is smaller than the spin splitting, and the fact impurity vertex corrections vanish in this system, we argue that the observed spin Hall effect should be in the intrinsic regime.
Date:
January 15, 2010
Creator:
Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type:
Article
System:
The UNT Digital Library
Quantum Spin Hall Effect
The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2 e/4{pi}. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.
Date:
January 15, 2010
Creator:
Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type:
Article
System:
The UNT Digital Library
Spin Splitting and Spin Current in Strained Bulk Semiconductors
We present a theory for two recent experiments in bulk strained semiconductors and show that a new, previously overlooked, strain spin-orbit coupling term may play a fundamental role. We propose simple experiments that could clarify the origin of strain-induced spin-orbit coupling terms in inversion asymmetric semiconductors. We predict that a uniform magnetization parallel to the electric field will be induced in the samples studied in for specific directions of the applied electric field. We also propose special geometries to detect spin currents in strained semiconductors.
Date:
January 15, 2010
Creator:
Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type:
Article
System:
The UNT Digital Library
Final Report
The year 2008 resulted in 99 scans that were funded through NIH agencies. An additional 43 MRI scans were funded by industry. Over 250 scans were acquired by various investigators as �pilot� data to be used for future grant applications. While these numbers are modest in comparison to most busy research MRI Centers, they are in line with that of a newly established MRI research facility. The initial 12-18 months of operation were primarily dedicated to establishing new IRB approved research studies, and acquiring pilot data for future grant applications. During the year 2009 the MRI Center continued to show positive growth with respect to funded studies and the number of scan sessions. The number of NIH sponsored scans increased to 242 and the number of industry funded studies climbed to 81. This more than doubled our numbers of funded scans over the previous year. In addition, 398 scans were acquired as pilot data; most of which were fMRI�s. The MRI Center continued to expand with additional researchers who were interested in probing the brain�s response to chronic pain. Other studies looked at regions of brain activation in patients with impulsivity disorders; including smokers. A large majority of the imaging …
Date:
August 15, 2013
Creator:
Bernstein, Ira Mark
Object Type:
Text
System:
The UNT Digital Library
Bounds and self-consistent estimates for elastic constants of polycrystals of hcp solid He{sup 4}
Recent advances in methods for computing both Hashin-Shtrikman bounds and related selfconsistent (or CPA) estimates of elastic constants for polycrystals composed of randomly oriented crystals can be applied successfully to hexagonal close packed solid He{sup 4}. In particular, since the shear modulus C{sub 44} of hexagonal close-packed solid He is known to undergo large temperature variations when 20 mK {<=}#20; T {<=}#20; 200 mK, bounds and estimates computed with this class of effective medium methods, while using C{sub 44} {r_arrow} 0 as a proxy for melting, are found to be both qualitatively and quantitatively very similar to prior results obtained using Monte Carlo methods. Hashin- Shtrikman bounds provide significantly tighter constraints on the polycrystal behavior than do the traditional Voigt and Reuss bounds.
Date:
February 15, 2012
Creator:
Berryman, J. G.
Object Type:
Article
System:
The UNT Digital Library
Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry
For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI earth system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous …
Date:
May 15, 2010
Creator:
Berryman, J.G.
Object Type:
Article
System:
The UNT Digital Library
Fast Beam-Based BPM Calibration
The Alignment Diagnostic System (ADS) of the LCLS undulator system indicates that the 33 undulator quadrupoles have extremely high position stability over many weeks. However, beam trajectory straightness and lasing efficiency degrade more quickly than this. A lengthy Beam Based Alignment (BBA) procedure must be executed every two to four weeks to re-optimize the X-ray beam parameters. The undulator system includes RF cavity Beam Position Monitors (RFBPMs), several of which are utilized by an automatic feedback system to align the incoming electron-beam trajectory to the undulator axis. The beam trajectory straightness degradation has been traced to electronic drifts of the gain and offset of the BPMs used in the beam feedback system. To quickly recover the trajectory straightness, we have developed a fast beam-based procedure to recalibrate the BPMs. This procedure takes advantage of the high-precision monitoring capability of the ADS, which allows highly repeatable positioning of undulator quadrupoles. This report describes the ADS, the position stability of the LCLS undulator quadrupoles, and some results of the new recovery procedure.
Date:
October 15, 2012
Creator:
Bertsche, K.; Loos, H.; Nuhn, H. D. & Peters, F.
Object Type:
Article
System:
The UNT Digital Library
CRS Issue Statement on Intelligence Policy
This report contains the distinction between foreign and law enforcement intelligence that remain important when civil liberties and privacy rights of U.S. persons are involved.
Date:
January 15, 2010
Creator:
Best, Richard A., Jr.
Object Type:
Report
System:
The UNT Digital Library
Intelligence, Surveillance, and Reconnaissance (ISR) Acquisition: Issues for Congress
This report discusses Congressional issues regarding Intelligence, Surveillance, and Reconnaissance (ISR) systems, which are integral components of both national policymaking and military operations, including counterterrorism operations. ISR systems are costly and complicated, and the relationships among organizations responsible for designing and operating these systems are equally complicated.
Date:
June 15, 2010
Creator:
Best, Richard A., Jr.
Object Type:
Report
System:
The UNT Digital Library
The National Counterterrorism Center (NCTC)--Responsibilities and Potential Congressional Concerns
This report looks at inadequacies present in the National Counterterrorism Center (NCTC) which prevent the Center from adequately performing its duty. These inadequacies include issues with agency organization, lack of resources, and a focus on threats from Yemen over domestic threats.
Date:
January 15, 2010
Creator:
Best, Richard A., Jr.
Object Type:
Report
System:
The UNT Digital Library