Aviation Safety: FAA Has An Opportunity to Enhance Safety and Improve Oversight of Initial Pilot Training (open access)

Aviation Safety: FAA Has An Opportunity to Enhance Safety and Improve Oversight of Initial Pilot Training

A statement of record issued by the Government Accountability Office with an abstract that begins "FAA’s pilot training requirements for certification of commercial pilots are not aligned with airline operations or emphasize skills that airlines consider important for greater aviation safety."
Date: March 20, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Internal Revenue Service: Interim Results of 2012 Tax Filing Season and Summary of the Fiscal Year 2013 Budget Request (open access)

Internal Revenue Service: Interim Results of 2012 Tax Filing Season and Summary of the Fiscal Year 2013 Budget Request

A letter report issued by the Government Accountability Office with an abstract that begins "In summary, so far this filing season, IRS"
Date: March 20, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Modernizing SSA Disability Programs: Preliminary Observations on Updates of Medical and Occupational Criteria (open access)

Modernizing SSA Disability Programs: Preliminary Observations on Updates of Medical and Occupational Criteria

Testimony issued by the Government Accountability Office with an abstract that begins "The Social Security Administration (SSA) has made several changes to improve the process it uses for updating its medical criteria, but continues to face challenges ensuring timely updates. SSA’s medical criteria for adults are in the form of listings of medical conditions and impairments organized under 14 body systems, which SSA periodically updates. To help ensure timely, periodic updates of a body system’s listings, SSA is moving away from comprehensively revising a body system’s listings toward a more targeted approach, wherein SSA selects for revision those impairment listings most in need of change. To date, SSA has completed comprehensive revisions of listings for 8 of the 14 body systems and now is in the process of reviewing them to determine whether and which targeted revisions are appropriate. In 2010, the SSA Commissioner set a 5-year cycle time for updating listings for each body system, replacing the agency’s prior practice of setting expiration dates for listings that ranged from 3 to 8 years and then frequently extending them. To further increase the timeliness and accuracy of decisions, SSA has sought recommendations from the Institute of Medicine and has acted …
Date: March 20, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Joint Strike Fighter: Restructuring Added Resources and Reduced Risk, but Concurrency Is Still a Major Concern (open access)

Joint Strike Fighter: Restructuring Added Resources and Reduced Risk, but Concurrency Is Still a Major Concern

Testimony issued by the Government Accountability Office with an abstract that begins ""
Date: March 20, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Managing Preparedness Grants and Assessing National Capabilities: Continuing Challenges Impede FEMA's Progress (open access)

Managing Preparedness Grants and Assessing National Capabilities: Continuing Challenges Impede FEMA's Progress

Testimony issued by the Government Accountability Office with an abstract that begins ""
Date: March 20, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Chromium isotopes as indicators of hexavalent chromium reduction (open access)

Chromium isotopes as indicators of hexavalent chromium reduction

This is the final report for a university research project which advanced development of a new technology for identifying chemical reduction of hexavalent chromium contamination in groundwater systems. Reduction renders mobile and toxic hexavalent chromium immobile and less toxic. The new method uses stable isotope ratio measurements, which are made using multicollector ICP-mass spectrometry. The main objectives of this project were completed during the project period and two peer-reviewed articles were published to disseminate the information gained.
Date: March 20, 2012
Creator: Johnson, Thomas M.
Object Type: Report
System: The UNT Digital Library
W+n-Jet Predictions With MC@NLO in Sherpa (open access)

W+n-Jet Predictions With MC@NLO in Sherpa

Results for the production of W-bosons in conjunction with up to three jets including parton shower corrections are presented and compared to recent LHC data. These results consistently incorporate the full next-to leading order QCD corrections through the MC{at}NLO method, as implemented in the SHERPA event generator, with the virtual corrections obtained from the BLACKHAT library.
Date: March 20, 2012
Creator: Hoeche, Stefan; Krauss, Frank; Schonherr, Marek & Siegert, Frank
Object Type: Article
System: The UNT Digital Library
Study of CP violation in Dalitz-plot analyses of B0 to K K-KS, B to K K-K , and B to KSKSK (open access)

Study of CP violation in Dalitz-plot analyses of B0 to K K-KS, B to K K-K , and B to KSKSK

We perform amplitude analyses of the decays B{sup 0} {yields} K{sup +}K{sup -}K{sub s}{sup 0}, B{sup +} {yields} K{sup +}K{sup -}K{sup +}, and B{sup +} {yields}, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470 x 10{sup 6} B{bar B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B{sup +} {yields} K{sup +}K{sup -}K{sup +}, we find a direct CP asymmetry in B{sup +} {yields} {phi}(1020)K{sup +} of A{sub CP} = (12.8 {+-} 4.4 {+-} 1.3)%, which differs from zero by 2.8{sigma}. For B{sup 0} {yields} K{sup +}K{sup -}K{sub s}{sup 0}, we measure the CP-violating phase {beta}{sub eff} ({phi}(1020)K{sub s}{sup 0}) = (21 {+-} 6 {+-} 2){sup o}. For B{sup +} {yields} K{sub s}{sup 0}K{sub s}{sup 0}K{sup +}, we measure an overall direct CP asymmetry of A{sub CP} = (4{sub -5}{sup +4} {+-} 2)%. We also perform an angular-moment analysis of the three channels, and determine that the f{sub X}(1500) state can be described well by the sum of the resonances f{sub 0}(1500), f{prime}{sub 2}(1525), and f{sub 0}(1710).
Date: March 20, 2012
Creator: Lees, J.P.
Object Type: Article
System: The UNT Digital Library
Hiding a Heavy Higgs Boson at the 7 TeV LHC (open access)

Hiding a Heavy Higgs Boson at the 7 TeV LHC

A heavy Standard Model Higgs boson is not only disfavored by electroweak precision observables but is also excluded by direct searches at the 7 TeV LHC for a wide range of masses. Here, we examine scenarios where a heavy Higgs boson can be made consistent with both the indirect constraints and the direct null searches by adding only one new particle beyond the Standard Model. This new particle should be a weak multiplet in order to have additional contributions to the oblique parameters. If it is a color singlet, we find that a heavy Higgs with an intermediate mass of 200-300 GeV can decay into the new states, suppressing the branching ratios for the standard model modes, and thus hiding a heavy Higgs at the LHC. If the new particle is also charged under QCD, the Higgs production cross section from gluon fusion can be reduced significantly due to the new colored particle one-loop contribution. Current collider constraints on the new particles allow for viable parameter space to exist in order to hide a heavy Higgs boson. We categorize the general signatures of these new particles, identify favored regions of their parameter space and point out that discovering or excluding …
Date: March 20, 2012
Creator: Bai, Yang; Fan, JiJi & Hewett, JoAnne L.
Object Type: Article
System: The UNT Digital Library
The HARNESS Workbench: Unified and Adaptive Access to Diverse HPC Platforms (open access)

The HARNESS Workbench: Unified and Adaptive Access to Diverse HPC Platforms

The primary goal of the Harness WorkBench (HWB) project is to investigate innovative software environments that will help enhance the overall productivity of applications science on diverse HPC platforms. Two complementary frameworks were designed: one, a virtualized command toolkit for application building, deployment, and execution, that provides a common view across diverse HPC systems, in particular the DOE leadership computing platforms (Cray, IBM, SGI, and clusters); and two, a unified runtime environment that consolidates access to runtime services via an adaptive framework for execution-time and post processing activities. A prototype of the first was developed based on the concept of a 'system-call virtual machine' (SCVM), to enhance portability of the HPC application deployment process across heterogeneous high-end machines. The SCVM approach to portable builds is based on the insertion of toolkit-interpretable directives into original application build scripts. Modifications resulting from these directives preserve the semantics of the original build instruction flow. The execution of the build script is controlled by our toolkit that intercepts build script commands in a manner transparent to the end-user. We have applied this approach to a scientific production code (Gamess-US) on the Cray-XT5 machine. The second facet, termed Unibus, aims to facilitate provisioning and aggregation …
Date: March 20, 2012
Creator: Sunderam, Vaidy S.
Object Type: Report
System: The UNT Digital Library
Enhancing trappable antiproton populations through deceleration and frictional cooling (open access)

Enhancing trappable antiproton populations through deceleration and frictional cooling

CERN currently delivers antiprotons for trapping experiments with the Antiproton Decelerator (AD), which slows the antiprotons down to about 5 MeV.This energy is currently too high for direct trapping, and thick foils are used to slow down the beam to energies which can be trapped.To allow further deceleration to $\sim 100 \;\mbox{keV}$, CERN is initiating the construction of ELENA,consisting of a ring which will combine RF deceleration and electron cooling capabilities. We describe a simple frictionalcooling scheme that can serve to provide significantly improved trapping efficiency, either directly from the AD or first usinga standard deceleration mechanism (induction linac or RFQ). This scheme could be implemented in a short time.The device itself is short in length, uses accessible voltages, and at reasonable cost could serve in the interim beforeELENA becomes operational, or possibly in lieu of ELENA for some experiments. Simple theory and simulations provide a preliminary assessment of theconcept and its strengths and limitations, and highlight important areas for experimental studies, in particular to pin down the level of multiplescattering for low-energy antiprotons. We show that the frictional cooling scheme can provide a similar energy spectrum to that of ELENA,but with higher transverse emittances.
Date: March 20, 2012
Creator: Zolotorev, Max; Sessler, Andrew; Penn, Gregory; Wurtele, Jonathan S. & Charman, Andrew E.
Object Type: Article
System: The UNT Digital Library
RIMS Analysis of Ion Induced Fragmentation of Molecules Sputtered from an Enriched U3O8 Matrix (open access)

RIMS Analysis of Ion Induced Fragmentation of Molecules Sputtered from an Enriched U3O8 Matrix

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Date: March 20, 2012
Creator: Willingham, D.; Savina, M. R.; Knight, K. B.; Pellin, M. J. & Hutcheon, I. D.
Object Type: Article
System: The UNT Digital Library
2011 Annual Summary Report for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada National Security Site, Nye County, Nevada: Review of the Performance Assessments and Composite Analyses (open access)

2011 Annual Summary Report for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada National Security Site, Nye County, Nevada: Review of the Performance Assessments and Composite Analyses

The Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site (National Security Technologies, LLC, 2007a) requires an annual review to assess the adequacy of the Performance Assessments (PAs) and Composite Analyses (CAs), with the results submitted annually to U.S. Department of Energy (DOE) Office of Environmental Management. The Disposal Authorization Statements for the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) also require that such reviews be made and that secondary or minor unresolved issues be tracked and addressed as part of the maintenance plan (DOE, 1999a; 2000). The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office performed an annual review of the Area 3 and Area 5 RWMS PAs and CAs for fiscal year (FY) 2011. This annual summary report presents data and conclusions from the FY 2011 review, and determines the adequacy of the PAs and CAs. Operational factors (e.g., waste forms and containers, facility design, and waste receipts), closure plans, monitoring results, and research and development (R and D) activities were reviewed to determine the adequacy of the PAs. Likewise, the environmental restoration activities at the …
Date: March 20, 2012
Creator: NSTec Environmental Management
Object Type: Report
System: The UNT Digital Library
APPLICATION OF COLUMN EXTRACTION METHOD FOR IMPURITIES ANALYSIS ON HB-LINE PLUTONIUM OXIDE IN SUPPORT OF MOX FEED PRODUCT SPECIFICATIONS (open access)

APPLICATION OF COLUMN EXTRACTION METHOD FOR IMPURITIES ANALYSIS ON HB-LINE PLUTONIUM OXIDE IN SUPPORT OF MOX FEED PRODUCT SPECIFICATIONS

The current mission at H-Canyon involves the dissolution of an Alternate Feedstocks 2 (AFS-2) inventory that contains plutonium metal. Once dissolved, HB-Line is tasked with purifying the plutonium solution via anion exchange, precipitating the Pu as oxalate, and calcining to form plutonium oxide (PuO{sub 2}). The PuO{sub 2} will provide feed product for the Mixed Oxide (MOX) Fuel Fabrication Facility, and the anion exchange raffinate will be transferred to H-Canyon. The results presented in this report document the potential success of the RE resin column extraction application on highly concentrated Pu samples to meet MOX feed product specifications. The original 'Hearts Cut' sample required a 10000x dilution to limit instrument drift on the ICP-MS method. The instrument dilution factors improved to 125x and 250x for the sample raffinate and sample eluent, respectively. As noted in the introduction, the significantly lower dilutions help to drop the total MRL for the analyte. Although the spike recoveries were half of expected in the eluent for several key elements, they were between 94-98% after Nd tracer correction. It is seen that the lower ICD limit requirements for the rare earths are attainable because of less dilution. Especially important is the extremely low Ga limit …
Date: March 20, 2012
Creator: Jones, M.; Diprete, D. & Wiedenman, B.
Object Type: Report
System: The UNT Digital Library
Federal Radiological Monitoring and Assessment Center Health and Safety Manual (open access)

Federal Radiological Monitoring and Assessment Center Health and Safety Manual

This manual is a tool to provide information to all responders and emergency planners and is suggested as a starting point for all organizations that provide personnel/assets for radiological emergency response. It defines the safety requirements for the protection of all emergency responders. The intent is to comply with appropriate regulations or provide an equal level of protection when the situation makes it necessary to deviate. In the event a situation arises which is not addressed in the manual, an appropriate management-level expert will define alternate requirements based on the specifics of the emergency situation. This manual is not intended to pertain to the general public.
Date: March 20, 2012
Creator: Group, FRMAC Health and Safety Working
Object Type: Report
System: The UNT Digital Library
Measurement of Hadronic Event Shapes and Jet Substructure in Proton-Proton Collisions at 7.0 TeV Center-of-Mass Energy with the ATLAS Detector at the Large Hadron Collider (open access)

Measurement of Hadronic Event Shapes and Jet Substructure in Proton-Proton Collisions at 7.0 TeV Center-of-Mass Energy with the ATLAS Detector at the Large Hadron Collider

This thesis presents the first measurement of 6 hadronic event shapes in proton-proton collisions at a center-of-mass energy of {radical}s = 7 TeV using the ATLAS detector at the Large Hadron Collider. Results are presented at the particle-level, permitting comparisons to multiple Monte Carlo event generator tools. Numerous tools and techniques that enable detailed analysis of the hadronic final state at high luminosity are described. The approaches presented utilize the dual strengths of the ATLAS calorimeter and tracking systems to provide high resolution and robust measurements of the hadronic jets that constitute both a background and a signal throughout ATLAS physics analyses. The study of the hadronic final state is then extended to jet substructure, where the energy flow and topology within individual jets is studied at the detector level and techniques for estimating systematic uncertainties for such measurements are commissioned in the first data. These first substructure measurements in ATLAS include the jet mass and sub-jet multiplicity as well as those concerned with multi-body hadronic decays and color flow within jets. Finally, the first boosted hadronic object observed at the LHC - the decay of the top quark to a single jet - is presented.
Date: March 20, 2012
Creator: Miller, David Wilkins
Object Type: Report
System: The UNT Digital Library
ENDF/B-VII.1 versus ENDF/B-VII.0: What's Different? (open access)

ENDF/B-VII.1 versus ENDF/B-VII.0: What's Different?

Recently the new ENDF/B-VII.1 library was released; this completely replaces the earlier ENDF/B-VII.0 library. One of the first questions we ask about a new library is: What's Different? Here I attempt to at least partially answer this question. I present results in both tabulated form (so you can quickly determine if any evaluations of interest to you have changed), and graphic form (so that you can see how much evaluations have changed and in what energy ranges). For the table I have compared what I refer to as the ENDF neutron data, namely MF=1 through 6. Here I did a character-by-character comparison of the same sections (MF/MT) that appear I both ENDF/B-VII.0 and VII.1; here I found differences in 170 evaluations. For the plots I have only compared the total cross sections for all evaluations that are common to both libraries, and I found that of the 423 evaluations in ENDF/B-VII.1, 120 of these have total cross sections that differ by 1% or more from the evaluation of the same isotope in ENDF/B-VII.0. This should be considered only a preliminary comparison; obviously there can be more subtle important differences that do not effect of total cross sections. Here I present …
Date: March 20, 2012
Creator: Cullen, D E
Object Type: Report
System: The UNT Digital Library
Initiation and Detonation Physics on Millimeter Scales (open access)

Initiation and Detonation Physics on Millimeter Scales

The LLNL Detonation Science Project has a major interest in understanding the physics of detonation on a millimeter scale. This report summarizes the rate stick experiment results of two high explosives. The GO/NO-GO threshold between varying diameters of ultra-fine TATB (ufTATB) and LX-16 were recorded on an electronic streak camera and analyzed. This report summarizes the failure diameters of rate sticks for ufTATB and LX-16. Failure diameter for the ufTATB explosive, with densities at 1.80 g/cc, begin at 2.34 mm (not maintaining detonation velocity over the entire length of the rate stick). ufTATB rate sticks at the larger 3.18 mm diameter maintain a constant detonation velocity over the complete length. The PETN based and LLNL developed explosive, LX-16, with densities at 1.7 g/cc, shows detonation failure between 0.318 mm and 0.365 mm. Additional tests would be required to narrow this failure diameter further. Many of the tested rate sticks were machined using a femtosecond laser focused into a firing tank - in case of accidental detonation.
Date: March 20, 2012
Creator: Philllips, D F; Benterou, J J & May, C A
Object Type: Report
System: The UNT Digital Library
Ultracoatings: Enabling Energy and Power Solutions in High Contact Stress Environments through next-generation Nanocoatings Final Technical Report (open access)

Ultracoatings: Enabling Energy and Power Solutions in High Contact Stress Environments through next-generation Nanocoatings Final Technical Report

A review of current commercially available, industrial-grade, low friction coatings will show that interfacial contact pressures nearing 1GPa ({approx}150ksi) inherently limit surface engineering solutions like WC, TiN, TiAlN, and so forth. Extremely hard coatings, then, are often pursued as the principle path, although they too are not without significant limitations. A majority of these compounds are inherently brittle in nature or may not pair well with their mating substrate. In either case, their durability in high contact stress environments is compromised. In parallel to thin film coatings, many conventional surface treatments do not yield an interface hard enough to withstand extreme stresses under load. New research into advanced, nanocomposite materials like (Ti, Zr)B2 shows great promise. Bulk compacts of this compound have demonstrated an order of magnitude better wear resistance than current offerings, notably materials like tungsten carbide. At a laboratory level, the (Ti,Zr)B2 nanocomposite material exhibited abrasive and erosive wear resistance nearly ten times better than existing mixed-phase boride systems. In ASTM abrasion and erosion testing, these new compositions exhibit wear resistance superior to other known advanced materials such as RocTec 500 and 'Borazon' cubic boron nitride. Many significant challenges exist for mass production of (Ti, Zr)B2, one of …
Date: March 20, 2012
Creator: Higdon, Clifton B., III
Object Type: Report
System: The UNT Digital Library
Asynchronous Checkpoint Migration with MRNet in the Scalable Checkpoint / Restart Library (open access)

Asynchronous Checkpoint Migration with MRNet in the Scalable Checkpoint / Restart Library

Applications running on today's supercomputers tolerate failures by periodically saving their state in checkpoint files on stable storage, such as a parallel file system. Although this approach is simple, the overhead of writing the checkpoints can be prohibitive, especially for large-scale jobs. In this paper, we present initial results of an enhancement to our Scalable Checkpoint/Restart Library (SCR). We employ MRNet, a tree-based overlay network library, to transfer checkpoints from the compute nodes to the parallel file system asynchronously. This enhancement increases application efficiency by removing the need for an application to block while checkpoints are transferred to the parallel file system. We show that the integration of SCR with MRNet can reduce the time spent in I/O operations by as much as 15x. However, our experiments exposed new scalability issues with our initial implementation. We discuss the sources of the scalability problems and our plans to address them.
Date: March 20, 2012
Creator: Mohror, K.; Moody, A. & de Supinski, B. R.
Object Type: Article
System: The UNT Digital Library
Direct Detection of Sub-GeV Dark Matter (open access)

Direct Detection of Sub-GeV Dark Matter

Direct detection strategies are proposed for dark matter particles with MeV to GeV mass. In this largely unexplored mass range, dark matter scattering with electrons can cause single-electron ionization signals, which are detectable with current technology. Ultraviolet photons, individual ions, and heat are interesting alternative signals. Focusing on ionization, we calculate the expected dark matter scattering rates and estimate the sensitivity of possible experiments. Backgrounds that may be relevant are discussed. Theoretically interesting models can be probed with existing technologies, and may even be within reach using ongoing direct detection experiments. Significant improvements in sensitivity should be possible with dedicated experiments, opening up a window to new regions in dark matter parameter space.
Date: March 20, 2012
Creator: Essig, Rouven; Mardon, Jeremy & Volansky, Tomer
Object Type: Article
System: The UNT Digital Library
Scalla: Structured Cluster Architecture for Low Latency Access (open access)

Scalla: Structured Cluster Architecture for Low Latency Access

Scalla is a distributed low-latency file access system that incorporates novel techniques that minimize latency and maximize scalability over a large distributed system with a distributed namespace. Scalla's techniques have shown to be effective in nearly a decade of service for the high-energy physics community using commodity hardware and interconnects. We describe the two components used in Scalla that are instrumental in its ability to provide low-latency, fault-tolerant name resolution and load distribution, and enable its use as a high-throughput, low-latency communication layer in the Qserv system, the Large Synoptic Survey Telescope's (LSST's) prototype astronomical query system. Scalla arguably exceeded its three main design objectives: low latency, scaling, and recoverability. In retrospect, these objectives were met using a simple but effective design. Low latency was met by uniformly using linear or constant time algorithms in all high-use paths, avoiding locks whenever possible, and using compact data structures to maximize the memory caching efficiency. Scaling was achieved by architecting the system as a 64-ary tree. Nodes can be added easily and as the number of nodes increases, search performance increases at an exponential rate. Recoverability is inherent in that no permanent state information is maintained and whatever state information is needed …
Date: March 20, 2012
Creator: Hanushevsky, Andrew & Wang, Daniel L.
Object Type: Article
System: The UNT Digital Library
Free MHD Shear Layers In The Presence Of Rotation And Magnetic Field (open access)

Free MHD Shear Layers In The Presence Of Rotation And Magnetic Field

We present an experimental and numerical study of hydrodynamic and magnetohydrodynamic free shear layers and their stability. We first examine the experimental measurement of globally unstable hydrodynamic shear layers in the presence of rotation, and their range of instability. These are compared to numerical simulations, which are used to explain the modification of the shear layer and thus the critical Rossby number for stability. Magnetic fields are then applied to these scenarios, and globally unstable magnetohydrodynamic shear layers generated. These too are compared to numerical simulations, showing behavior consistent with the hydrodynamic case and previously reported measurements.
Date: March 20, 2012
Creator: Spence, E. J.; Roach, A. H.; Edlund, E. M.; Sloboda, P. & Ji, H.
Object Type: Report
System: The UNT Digital Library
Hadronic form factor models and spectroscopy within the gauge/gravity correspondence (open access)

Hadronic form factor models and spectroscopy within the gauge/gravity correspondence

We show that the nonperturbative light-front dynamics of relativistic hadronic bound states has a dual semiclassical gravity description on a higher dimensional warped AdS space in the limit of zero quark masses. This mapping of AdS gravity theory to the boundary quantum field theory, quantized at fixed light-front time, allows one to establish a precise relation between holographic wave functions in AdS space and the light-front wavefunctions describing the internal structure of hadrons. The resulting AdS/QCD model gives a remarkably good accounting of the spectrum, elastic and transition form factors of the light-quark hadrons in terms of one parameter, the QCD gap scale. The light-front holographic approach described here thus provides a frame-independent first approximation to the light-front Hamiltonian problem for QCD. This article is based on lectures at the Niccolo Cabeo International School of Hadronic Physics, Ferrara, Italy, May 2011.
Date: March 20, 2012
Creator: de Teramond, Guy F.; U., /Costa Rica & Brodsky, Stanley J.
Object Type: Article
System: The UNT Digital Library