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Impaired fertility in T-stock female mice after superovulation (open access)

Impaired fertility in T-stock female mice after superovulation

Superovulation of female mice with exogenous gonadotrophins is routinely used for increasing the number of eggs ovulated by each female in reproductive and developmental studies. We report an unusual effect of superovulation on fertilization in mice. In vivo matings of superovulated T-stock females with B6C3F1 males resulted in a 2-fold reduction (P<0.001) in the frequencies of fertilized eggs compared to control B6C3F1 matings. In addition, {approx}22 hr after mating only 15% of fertilized eggs recovered in T-stock females had reached the metaphase stage of the first cleavage division versus 87% in B6C3F1 females (P < 0.0001). Matings with T-stock males did not improve the reproductive performance of T-stock females. To investigate the possible cause(s) for the impaired fertilization and zygotic development, the experiments were repeated using in vitro fertilization. Under these conditions, the frequencies of fertilized eggs were not different in superovulated T-stock and B6C3F1 females (51.7% {+-} 6.0 and 64.5% {+-}3.8, P=0.10). There was a 7-fold increase in the frequencies of fertilized T-stock eggs that completed the first cell cycle of development after in vitro versus in vivo fertilization. These results rule out an intrinsic deficiency of the T-stock oocyte as the main reason for the impaired fertility after …
Date: December 5, 2003
Creator: Wyrobek, A J; Bishop, J B; Marchetti, F & Zudova, D
System: The UNT Digital Library
Hyperspectral Imaging of Functional Patterns for Disease Assessment and Treatment Monitoring (open access)

Hyperspectral Imaging of Functional Patterns for Disease Assessment and Treatment Monitoring

We have designed and built a six-band multi-spectral NIR imaging system used in clinical testing on cancer patients. From our layered tissue model, we create blood volume and blood oxygenation images for patient treatment monitoring.
Date: December 5, 2003
Creator: Hassan, Moinuddin; Hattery, David; Vogel, Abby; Chernomorkik, Victor; Demos, Stavros; Aleman, Karen et al.
System: The UNT Digital Library
A Quantitative Comparison of Numerical Methods for the Compressible Euler Equations: Fifth-order WENO and Piecewise-Linear Godunov (open access)

A Quantitative Comparison of Numerical Methods for the Compressible Euler Equations: Fifth-order WENO and Piecewise-Linear Godunov

A numerical study is undertaken comparing a fifth-order version of the weighted essentially non-oscillatory numerical (WENO5) method to a modern piecewise-linear, second-order, version of Godunov's (PLMDE) method for the compressible Euler Equations. A series of one-dimensional test problems are examined beginning with classical linear problems and ending with complex shock interactions. The problems considered are: (1) linear advection of a Gaussian pulse in density, (2) Sod's shock tube problem, (3) the ''peak'' shock tube problem, (4) a version of the Shu and Osher shock entropy wave interaction and (5) the Woodward and Colella interacting shock wave problem. For each problem and method, run times, density error norms and convergence rates are reported for each method as produced from a common code test-bed. The linear problem exhibits the advertised convergence rate for both methods as well as the expected large disparity in overall error levels; WENO5 has the smaller errors and an enormous advantage in overall efficiency (in accuracy per unit CPU time). For the nonlinear problems with discontinuities, however, we generally see both first-order self-convergence of error as compared to an exact solution, or when an analytic solution is not available, a converged solution generated on an extremely fine grid. …
Date: November 5, 2003
Creator: Greenough, J A & Rider, W J
System: The UNT Digital Library
The Confinement Problem in Lattice Gauge Theory (open access)

The Confinement Problem in Lattice Gauge Theory

I review investigations of the quark confinement mechanism that have been carried out in the framework of SU(N) lattice gauge theory. The special role of Z(N) center symmetry is emphasized.
Date: March 5, 2003
Creator: Greensite, J.
System: The UNT Digital Library
International Benchmarking and Conference on Women in Physics (open access)

International Benchmarking and Conference on Women in Physics

International benchmarking and conference on women in physics.
Date: February 5, 2003
Creator: Franz, Judy R.
System: The UNT Digital Library
Finding Text Information in the Ocean of Electronic Documents (open access)

Finding Text Information in the Ocean of Electronic Documents

Information management in natural resources has become an overwhelming task. A massive amount of electronic documents and data is now available for creating informed decisions. The problem is finding the relevant information to support the decision-making process. Determining gaps in knowledge in order to propose new studies or to determine which proposals to fund for maximum potential is a time-consuming and difficult task. Additionally, available data stores are increasing in complexity; they now may include not only text and numerical data, but also images, sounds, and video recordings. Information visualization specialists at Pacific Northwest National Laboratory (PNNL) have software tools for exploring electronic data stores and for discovering and exploiting relationships within data sets. These provide capabilities for unstructured text explorations, the use of data signatures (a compact format for the essence of a set of scientific data) for visualization (Wong et al 2000), visualizations for multiple query results (Havre et al. 2001), and others (http://www.pnl.gov/infoviz ). We will focus on IN-SPIRE, a MS Windows vision of PNNL’s SPIRE (Spatial Paradigm for Information Retrieval and Exploration). IN-SPIRE was developed to assist information analysts find and discover information in huge masses of text documents.
Date: February 5, 2003
Creator: Medvick, Patricia A. & Calapristi, Augustin J.
System: The UNT Digital Library
Electronic and magnetic properties of zincblende half-metal superlattices (open access)

Electronic and magnetic properties of zincblende half-metal superlattices

Zincblende half-metallic compounds such as CrAs, with large magnetic moments and high Curie temperatures, are promising materials for spintronic applications. They explore layered materials, consisting of alternating layers of zincblende half-metals, by first principles calculations, and find that superlattices of (CrAs){sub 1}(MnAs){sub 1} and (CrAs){sub 2}(MnAs){sub 2} are half-metallic with magnetic moments of 7.0{mu}{sub B} and 14.0{mu}{sub B} per unit cell, respectively. They discuss the nature of the bonding and half-metallicity in these materials and, based on the understanding acquired, develop a simple expression for the magnetic moment in such materials. They explore the range of lattice constants over which half-metallicity is manifested, and suggest corresponding substrates for growth in thin film form.
Date: November 5, 2003
Creator: Fong, C Y; Qian, M C; Pask, J; Yang, L H & Dag, S
System: The UNT Digital Library
ALS user meeting features 10th anniversary celebration (open access)

ALS user meeting features 10th anniversary celebration

The Advanced Light Source (ALS) saw first light on October 5, 1993, not quite to the day but close to 10 years before the 2003 ALS Users Association meeting, held October 6-8. Fittingly, the proceedings included retrospectives from two of the key players in the early history of the ALS, David Attwood and Jay Marx, and a display of photographs chronicling its construction and commissioning. Science highlights, highlights from young researchers, and posters constituted the meat of the program on Monday and Tuesday morning, while workshops took over Tuesday afternoon and all day Wednesday.
Date: December 5, 2003
Creator: Robinson, Art
System: The UNT Digital Library
Studies of the N=90 region: The decay of 154Eu to 154Gd (open access)

Studies of the N=90 region: The decay of 154Eu to 154Gd

The decay of {sup 154}Eu {yields} {sup 154}Gd has been studied by {gamma}-ray singles and {gamma}-{gamma} coincidence spectroscopy using an array of 20 Compton-suppressed Ge detectors. The primary goal of the work was to confirm or refute a large number of questionable features in the decay scheme: the outcome is the removal of 8 levels from the previously adopted scheme, with the result that a new type of collective band is revealed. Many weak decay branches for the decay are clarified. These results are critical for understanding the structure of {sup 154}Gd and the N = 90 isotones; and the improved completeness of the decay scheme contributes to the use of {sup 154}Eu as a metrological standard.
Date: December 5, 2003
Creator: Kulp, W. D.; Wood, J. L.; Krane, K. S.; Loats, J.; Schmelzenbach, P.; Stapels, C. J. et al.
System: The UNT Digital Library
Atomic resolution of lithium ions in LiCoO{sub 2} (open access)

Atomic resolution of lithium ions in LiCoO{sub 2}

LiCoO{sub 2} is the most common lithium storage material used as positive electrode in lithium rechargeable batteries. Ordering of lithium and vacancies has a profound effect on the physical properties of Li{sub x}CoO{sub 2} and the electrochemical performances of lithium batteries. An exit surface wave (ESW) phase image reconstructed from experimental images obtained on the LBNL One-Angstrom Microscope (OAM) shows all three types of atoms in LiCoO{sub 2}.
Date: June 5, 2003
Creator: Shao-Horn, Yang; Croguennec, Laurence; Delmas, Claude; Nelson, E. Chris & O'Keefe, Michael A.
System: The UNT Digital Library
Miscoding properties of 1,N{sup 6}-ethanoadenine, a DNA adduct derived from reaction with antitumor agent 1,3-bis(2-chloroethyl)-1-nitrosourea (open access)

Miscoding properties of 1,N{sup 6}-ethanoadenine, a DNA adduct derived from reaction with antitumor agent 1,3-bis(2-chloroethyl)-1-nitrosourea

1,N{sup 6}-Ethanoadenine (EA) is an exocyclic adduct formed from DNA reaction with the antitumor agent, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). To understand the role of this adduct in the mechanism of mutagenicity or carcinogenicity by BCNU, an oligonucleotide with a site-specific EA was synthesized using phosphoramidite chemistry. We now report the in vitro miscoding properties of EA in translesion DNA synthesis catalyzed by mammalian DNA polymerases (pols) {alpha}, {beta}, {eta} and {iota}. These data were also compared with those obtained for the structurally related exocyclic adduct, 1,N{sup 6}-ethenoadenine ({var_epsilon}A). Using a primer extension assay, both pols {alpha} and {beta} were primarily blocked by EA or {var_epsilon}A with very minor extension. Pol {eta} a member of the Y family of polymerases, was capable of catalyzing a significant amount of bypass across both adducts. Pol {eta} incorporated all four nucleotides opposite EA and {var_epsilon}A, but with differential preferences and mainly in an error-prone manner. Human pol {iota}, a paralog of human pol {eta}, was blocked by both adducts with a very small amount of synthesis past {var_epsilon}A. It incorporated C and, to a much lesser extent, T, opposite either adduct. In addition, the presence of an A adduct, e.g. {var_epsilon}A, could affect the specificity of …
Date: March 5, 2003
Creator: Hang, Bo; Guliaev, Anton B.; Chenna, Ahmed & Singer, B.
System: The UNT Digital Library
Efficient airflow design for cleanrooms improves business bottom lines (open access)

Efficient airflow design for cleanrooms improves business bottom lines

Based on a review of airflow design factors and in-situ energy measurements in ISO Cleanliness Class-5 cleanrooms, this paper addresses the importance of energy efficiency in airflow design and opportunities of cost savings in cleanroom practices. The paper discusses design factors that can long lastingly affect cleanroom system performance, and demonstrates benefits of energy efficient cleanroom design from viewpoints of environmental control and business operations. The paper suggests that a high performance cleanroom should not only be effective in contamination control, but also be efficient in energy and environmental performance. The paper also suggests that energy efficient design practice stands to bring in immediate capital cost savings and operation cost savings, and should be regarded by management as a strategy to improve business bottom lines.
Date: January 5, 2003
Creator: Xu, Tengfang
System: The UNT Digital Library
Mechanical Behavior and Fractography of 304 Stainless Steel with High Hydrogen Concentration (open access)

Mechanical Behavior and Fractography of 304 Stainless Steel with High Hydrogen Concentration

Hydrogen embrittlement of 304 stainless steel with different hydrogen concentrations has been investigated. An electrochemical technique was used to effectively charge the high level of hydrogen into 304 stainless steel in a short period of time. At 25 ppm of hydrogen, 304 stainless steel loses 10 percent of its original mechanical strength and 20 percent plasticity. Although the ductile feature dominates the fractography, the brittle crown area near the outer surface shows the intergranular rupture effected by hydrogen. At 60 ppm of hydrogen, 304 stainless steel loses 23 percent of its strength and 38 percent plasticity, where the brittle mode dominates the fracture of the materials. Experimental results show that hydrogen damage to the performance of 304 stainless steel is significant even at very low levels. The fractograph analysis indicates the high penetration ability of hydrogen in 304 stainless steel. This work also demonstrates the advantages of the electrochemical charging technique in the study of hydrogen embrittlement.
Date: February 5, 2003
Creator: Au, M.
System: The UNT Digital Library
Effects of Point Sources in Trench Disposal of Radioactive Waste (open access)

Effects of Point Sources in Trench Disposal of Radioactive Waste

At the U. S. Department of Energy Savannah River Site, disposal of radioactive wastes in shallow trenches was simulated with vadose zone models and decoupled aquifer models. The vadose zone models provided contaminant fluxes to the aquifer models.
Date: February 5, 2003
Creator: Collard, L.B.
System: The UNT Digital Library
Working out the kinks: Understanding the fall and rise of energy use in China (open access)

Working out the kinks: Understanding the fall and rise of energy use in China

The causes of the decline in China's energy consumption between 1996 and 2000 are analyzed.
Date: March 5, 2003
Creator: Fridley, David G.; Sinton, Jonathan E. & Lewis, Joanna I.
System: The UNT Digital Library
Introduction to heavy meson decays and CP asymmetries (open access)

Introduction to heavy meson decays and CP asymmetries

These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B decays. The third lecture concerns with theoretically clean CP violation measurements that may become possible in the future, and some developments toward a better understanding of nonleptonic B decays. The conclusions include a subjective best buy list for the near future.
Date: February 5, 2003
Creator: Ligeti, Zoltan
System: The UNT Digital Library
The CDF data handling system (open access)

The CDF data handling system

The Collider Detector at Fermilab (CDF) records proton-antiproton collisions at center of mass energy of 2.0 TeV at the Tevatron collider. A new collider run, Run II, of the Tevatron started in April 2001. Increased luminosity will result in about 1 PB of data recorded on tapes in the next two years. Currently the CDF experiment has about 260 TB of data stored on tapes. This amount includes raw and reconstructed data and their derivatives. The data storage and retrieval are managed by the CDF Data Handling (DH) system. This system has been designed to accommodate the increased demands of the Run II environment and has proven robust and reliable in providing reliable flow of data from the detector to the end user. This paper gives an overview of the CDF Run II Data Handling system which has evolved significantly over the course of this year. An outline of the future direction of the system is given.
Date: November 5, 2003
Creator: Litvintsev, Dmitry O.
System: The UNT Digital Library
Hash sorter - firmware implementation and an application for the Fermilab BTeV level 1 trigger system (open access)

Hash sorter - firmware implementation and an application for the Fermilab BTeV level 1 trigger system

A hardware hash sorter for the Fermilab BTeV Level 1 trigger system will be presented. The has sorter examines track-segment data before the data are sent to a system comprised of 2500 Level 1 processors, and rearranges the data into bins based on the slope of track segments. They have found that by using the rearranged data, processing time is significantly reduced allowing the total number of processors required for the Level 1 trigger system to be reduced. The hash sorter can be implemented in an FPGA that is already included as part of the design of the trigger system. Hash sorting has potential applications in a broad area in trigger and DAQ systems. It is a simple O(n) process and is suitable for FPGA implementation. Several implementation strategies will also be discussed in this document.
Date: November 5, 2003
Creator: al., Jinyuan Wu et
System: The UNT Digital Library
NON-DESTRUCTIVE IN SITU SOIL CARBON ANALYSIS: PRINCIPLE AND RESULTS. (open access)

NON-DESTRUCTIVE IN SITU SOIL CARBON ANALYSIS: PRINCIPLE AND RESULTS.

Global warming is promoted by anthropogenic CO{sub 2} emissions into the atmosphere, while at the same time it is partially mitigated by carbon sequestration by terrestrial ecosystems. However, improvement in the understanding and monitoring of below ground carbon processes is essential for evaluating strategies for carbon sequestration including quantification of carbon stores for credits. A system for non-destructive in situ carbon monitoring in soil, based on inelastic neutron scattering (INS), is described. The system can be operated in stationary or scanning mode and measures soil to depth of approximately 30 cm. There is a good agreement between results obtained from INS and standard chemical analysis of soil cores collected from the same study site.
Date: May 5, 2003
Creator: WIELOPOLSKI, L.; MITRA, S.; HENDREY, G.; ROGERS, H.; TORBERT, A. & PRIOR, S.
System: The UNT Digital Library
Introduction to heavy meson decays and CP asymmetries (open access)

Introduction to heavy meson decays and CP asymmetries

These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B decays. The third lecture concerns with theoretically clean CP violation measurements that may become possible in the future, and some developments toward a better understanding of nonleptonic B decays. The conclusions include a subjective best buy list for the near future.
Date: February 5, 2003
Creator: Ligeti, Zoltan
System: The UNT Digital Library
RF impedance measurements on the DARHT-II accelerator intercell assembly (open access)

RF impedance measurements on the DARHT-II accelerator intercell assembly

We report upon recent experimental measurements made of RF properties of the intercell assembly of the second axis accelerator[1] of Dual Axis Radiographic Hydrodynamic Test (DARHT) facility at LANL. The intercells provide both pumping and diagnostic access to the main DARHT-II beamline. Their design includes a pumping plenum separated from the main beam pipe by return current rods together with RF shielding provided by a copper-coated stainless steel mesh. Measurements using the twin lead technique (see Ref. [2]) at low frequencies (f < 200 MHz) suggest a constant value for the ratio h of the radial and azimuthal magnetic field components to which the transverse impedance is linearly related. We find that these results compare favorably to predictions from a simple analytic, lumped circuit model which includes the effects of the mesh and return current rods. We also present RF loop-to-loop frequency scans above beam pipe cutoff ({approx}600 MHz) showing the existence of many RF modes with relatively high Q's.
Date: May 5, 2003
Creator: Fawley, William M.; Eylon, Shmuel & Briggs, Richard
System: The UNT Digital Library
Study of indium and solder bumps for the BTeV Pixel Detector (open access)

Study of indium and solder bumps for the BTeV Pixel Detector

The pixel detector proposed for the BTeV experiment at the Fermilab Tevatron will use bump-bonding technology based on either Indium or Pb/Sn solder to connect the front-end readout chips to the silicon pixel sensors. We have studied the strength of the bumps by visual inspection of the bumps bonding silicon sensor modules to dummy chips made out of glass. The studies were done before and after thermal cycles, exposed to intense irradiation, and with the assemblies glued to a graphite substrate. We have also carried out studies on effects of temperature changes on both types of bump bonds by observing the responses of single-chip pixel detectors to an Sr{sup 90} source. We report the results from these studies and our plan to measure the effect of cryogenic temperatures on the bumps.
Date: November 5, 2003
Creator: al., Simon W Kwan et
System: The UNT Digital Library
Parametric Techniques for Extreme-Contracts, High-Energy Petawatt Pulses (open access)

Parametric Techniques for Extreme-Contracts, High-Energy Petawatt Pulses

Prepulses are of great concern in high-power lasers: if their intensity is sufficiently high, they can heat and/or destroy a target before the arrival of the main pulse. For ultrahigh peak power lasers, for which focused intensity can exceed 10{sup 21} W/cm{sup 2}, a contrast of at least 10{sup 8} is the minimum requirement to avoid preionization of solid targets. Conventional preamplification stages do not meet this requirement, primarily due to prepulse originating from regenerative amplification. Optical parametric amplification (OPA) is well-known to generate pulses with a prepulse contrast equal to the gain of the amplifier, but it does not remove pre-existing prepulses. In this paper we describe a novel technique for contrast enhancement in cascaded optical parametric amplifiers (COPA). Based on cascaded idler utilization, COPA represents a versatile technique with a potentially infinite prepulse contrast enhancement. We have experimentally demonstrated COPA, producing a prepulse contrast of 10{sup 8}, limited by the sensitivity of measurement. A simple modification of the front end of a petawatt-type laser that utilizes optical parametric chirped pulse amplification (OPCPA) can yield unprecedented levels of prepulse contrast.
Date: September 5, 2003
Creator: Jovanovic, I; Wattellier, B & Barty, C P J
System: The UNT Digital Library
Testing a Low-Influence Spindle Drive Motor (open access)

Testing a Low-Influence Spindle Drive Motor

Precision spindles used for diamond turning and other applications requiring low error motion generally require a drive system that ideally applies a pure torque to the rotating spindle. Frequently a frameless motor, that is, one without its own bearings, is directly coupled to the spindle to make a compact and simple system having high resonant frequencies. Although in addition to delivering drive torque, asymmetries in the motor cause it to generate disturbance loads (forces and moments) which influence the spindle error motion of the directly coupled system. This paper describes the tests and results for a particular frameless, brushless DC motor that was originally developed for military and space applications requiring very low torque ripple. Because the construction of the motor should also lead to very low disturbance loads, it was selected for use on a new diamond turning and grinding machine under developed at Lawrence Livermore National Laboratory. The level of influence for this motor-spindle combination is expected to be of order one nanometer for radial and axial error motion.
Date: November 5, 2003
Creator: Hale, L; Wulff, T & Sedgewick, J
System: The UNT Digital Library