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Progress in Horizontal and Slant-Path Imaging Speckle Imaging (open access)

Progress in Horizontal and Slant-Path Imaging Speckle Imaging

The difficulty in terrestrial imaging over long horizontal or slant paths is that atmospheric aberrations and distortions reduce the resolution and contrast in images recorded at high resolution. This paper will describe the problem of horizontal-path imaging, briefly cover various methods for imaging over horizontal paths and then describe the speckle imaging method actively being pursued at LLNL. We will review some closer range (1-3 km range) imagery of people we have already published, as well as show new results of vehicles we have obtained over longer slant-range paths greater than 20 km.
Date: January 30, 2003
Creator: Carrano, C J
System: The UNT Digital Library
Spatial Coherence of Synchrotron Radiation (open access)

Spatial Coherence of Synchrotron Radiation

Synchrotron Radiation (SR) has been widely used since the 80's as a tool for many applications of UV, soft X rays and hard X rays in condensed matter physics, chemistry and biology. The evolution of SR sources towards higher brightness has led to the design of low-emittance electron storage rings (emittance is the product of beam size and divergence), and the development of special source magnetic structures, as undulators. This means that more and more photons are available on a narrow bandwidth and on a small collimated beam; in other words there is the possibility of getting a high power in a coherent beam. In most applications, a monochromator is used, and the temporal coherence of the light is given by the monochromator bandwidth. With smaller and smaller sources, even without the use of collimators, the spatial coherence of the light has become appreciable, first in the UV and soft X ray range, and then also with hard X rays. This has made possible new or improved experiments in interferometry, microscopy, holography, correlation spectroscopy, etc. In view of these recent possibilities and applications, it is useful to review some basic concepts about spatial coherence of SR, and its measurement and …
Date: October 30, 2003
Creator: Marchesini, S & Coisson, R
System: The UNT Digital Library
Impact of Neutrino Oscillation Measurements on Theory (open access)

Impact of Neutrino Oscillation Measurements on Theory

Neutrino oscillation data had been a big surprise to theorists, and indeed they have ongoing impact on theory. I review what the impact has been, and what measurements will have critical impact on theory in the future.
Date: November 30, 2003
Creator: Murayama, Hitoshi
System: The UNT Digital Library
High current heavy ion beams in the electrostatic plasmalens (open access)

High current heavy ion beams in the electrostatic plasmalens

We describe applications of the electrostatic plasma lens for manipulating and focusing moderate energy, high current, broad, heavy ion beams. Use of a plasma lens in this way has been successfully demonstrated in a series of experiments carried out collaboratively between IP NASU (Kiev) and LBNL (Berkeley) in recent years. Here we briefly review the plasma lens fundamentals, peculiarities of focusing heavy ion beams, and summarize some recent developments (experiments, computer simulations, theory). We show that there is a very narrow range of low magnetic field for which the optical properties of the lens improve markedly. This opens up some attractive possibilities for the development of a new-generation compact lens based on permanent magnets. Preliminary experimental results obtained at Kiev and Berkeley on the operation of a permanent magnet plasma lens for manipulating wide aperture high-current heavy ion beams are presented and summarized.
Date: September 30, 2003
Creator: Goncharov, A.A. & Brown, I.G.
System: The UNT Digital Library
An evaluation of the active fracture concept with modelingunsaturated flow and transport in a fractured meter-sized block ofrock (open access)

An evaluation of the active fracture concept with modelingunsaturated flow and transport in a fractured meter-sized block ofrock

Numerical simulation is an effective and economical tool for optimally designing laboratory experiments and deriving practical experimental conditions. We executed a detailed numerical simulation study to examine the active fracture concept (AFC, Liu et al., 1998) using a cubic meter-sized block model. The numerical simulations for this study were performed by applying various experimental conditions, including different bottom flow boundaries, varying injection rates, and different fracture-matrix interaction (by increasing absolute matrix permeability at the fracture matrix boundary) for a larger fracture interaction under transient or balanced-state flow regimes. Two conceptual block models were developed based on different numerical approaches: a two-dimensional discrete-fracture-network model (DFNM) and a one-dimensional dual continuum model (DCM). The DFNM was used as a surrogate for a natural block to produce synthetic breakthrough curves of water and tracer concentration under transient or balanced-state conditions. The DCM is the approach typically used for the Yucca Mountain Project because of its computational efficiency. The AFC was incorporated into the DCM to capture heterogeneous flow patterns that occur in unsaturated fractured rocks. The simulation results from the DCM were compared with the results from the DFNM to determine whether the DCM could predict the water flow and tracer transport observed …
Date: May 30, 2003
Creator: Seol, Yongkoo; Kneafsey, Timothy J. & Ito, Kazumasa
System: The UNT Digital Library
Electron microscopy of biological macromolecules: Bridging the gapbetween what physics allows and what we currently can get (open access)

Electron microscopy of biological macromolecules: Bridging the gapbetween what physics allows and what we currently can get

The resolution achieved in low-dose electron microscopy of biological macromolecules is significantly worse than what can be obtained on the same microscopes with more robust specimens. When two-dimensional crystals are used, it is also apparent that the high-resolution image contrast is much less than what it could be if the images were perfect. Since specimen charging is one factor that might limit the contrast and resolution achieved with biological specimens, we have investigated the use of holey support films that have been coated with a metallic film before depositing specimens onto a thin carbon film that is suspended over the holes. Monolayer crystals of paraffin (C44H90) are used as a test specimen for this work because of the relative ease in imaging Bragg spacings at {approx}0.4 nm resolution, the relative ease of measuring the contrast in these images, and the similar degree of radiation sensitivity of these crystals when compared to biological macromolecules. A metallic coating on the surrounding support film does, indeed, produce a significant improvement in the high-resolution contrast for a small fraction of the images. The majority of images show little obvious improvement, however, and even the coated area of the support film continues to show a …
Date: April 30, 2003
Creator: Typke, Dieter; Downing, Kenneth H. & Glaeser, Robert M.
System: The UNT Digital Library
Comparative genomic analysis as a tool for biologicaldiscovery (open access)

Comparative genomic analysis as a tool for biologicaldiscovery

Biology is a discipline rooted in comparisons. Comparative physiology has assembled a detailed catalogue of the biological similarities and differences between species, revealing insights into how life has adapted to fill a wide-range of environmental niches. For example, the oxygen and carbon dioxide carrying capacity of vertebrate has evolved to provide strong advantages for species respiring at sea level, at high elevation or within water. Comparative- anatomy, -biochemistry, -pharmacology, -immunology and -cell biology have provided the fundamental paradigms from which each discipline has grown.
Date: March 30, 2003
Creator: Nobrega, Marcelo A. & Pennacchio, Len A.
System: The UNT Digital Library
Insights from Human/Mouse genome comparisons (open access)

Insights from Human/Mouse genome comparisons

Large-scale public genomic sequencing efforts have provided a wealth of vertebrate sequence data poised to provide insights into mammalian biology. These include deep genomic sequence coverage of human, mouse, rat, zebrafish, and two pufferfish (Fugu rubripes and Tetraodon nigroviridis) (Aparicio et al. 2002; Lander et al. 2001; Venter et al. 2001; Waterston et al. 2002). In addition, a high-priority has been placed on determining the genomic sequence of chimpanzee, dog, cow, frog, and chicken (Boguski 2002). While only recently available, whole genome sequence data have provided the unique opportunity to globally compare complete genome contents. Furthermore, the shared evolutionary ancestry of vertebrate species has allowed the development of comparative genomic approaches to identify ancient conserved sequences with functionality. Accordingly, this review focuses on the initial comparison of available mammalian genomes and describes various insights derived from such analysis.
Date: March 30, 2003
Creator: Pennacchio, Len A.
System: The UNT Digital Library
Twenty-second Fungal Genetics Conference - Asilomar, 2003 (open access)

Twenty-second Fungal Genetics Conference - Asilomar, 2003

The purpose of the Twenty Second Fungal Genetics Conference is to bring together scientists and students who are interested in genetic approaches to studying the biology of filamentous fungi. It is intended to stimulate thinking and discussion in an atmosphere that supports interactions between scientists at different levels and in different disciplines. Topics range from the basic to the applied. Filamentous fungi impact human affairs in many ways. In the environment they are the most important agents of decay and nutrient turnover. They are used extensively in the food industry for the production of food enzymes such as pectinase and food additives such as citric acid. They are used in the production of fermented foods such as alcoholic drinks, bread, cheese, and soy sauce. More than a dozen species of mushrooms are used as foods directly. Many of our most important antibiotics, such as penicillin, cyclosporin, and lovastatin, come from fungi. Fungi also have many negative impacts on human health and economics. Fungi are serious pathogens in immuno-compromised patients. Fungi are the single largest group of plant pathogens and thus a serious limit on crop productivity throughout the world. Many fungi are allergenic, and mold contamination of residences and commercial …
Date: June 30, 2003
Creator: Walton, Jonathan D.
System: The UNT Digital Library
Apolipoprotein AIF gene variant S347 is associated with increased risk of coronary heart disease and lower apolipoprotein AIV plasma concentrations (open access)

Apolipoprotein AIF gene variant S347 is associated with increased risk of coronary heart disease and lower apolipoprotein AIV plasma concentrations

The impact of common variants in the apolipoprotein gene cluster (APOC3-A4-A5) on prospective CHD risk was examined in healthy UK men. Of the 2808 men followed over nine years, 187 had a clinically defined CHD event. Examination of 9 single nucleotide polymorphisms (SNPs) in this group revealed that homozygotes for APOA4 S347 had significantly increased risk of CHD [Hazard ratio (HR) of 2.07 (95%CI 1.04-4.12)] while men homozygous for APOC3 1100T were protected (HR 0.28 (95%CI 0.09-0.87)). In stepwise multiple regression analysis, after entering all the variants and adjusting for established risk factors APOA4 T347S alone remained in the model. Using nine-SNP haplotype analysis, highest risk-estimate haplotypes carried APOA4 S347 and rare alleles of the two flanking intergenic markers. The protective effect of APOC31100T could be explained by negative linkage disequilibrium with these alleles. To determine the association of APOA4 T347S with apoAIVlevels, the relationship was examined in over 1600 healthy young European men and women. S347 homozygotes had significantly lower apoAIV plasma levels (13.48 + 0.6mg/dl) compared to carriers of the T347 allele (14.85 + 0.12 mg/dl) (p=0.025). These results demonstrate that genetic variation in and around APOA4, independent of effects of TG, is associated with risk of CHD …
Date: January 30, 2003
Creator: Wong, Wai-man R.; Hawe, Emma; Li, Lai K.; Miller, George J.; Nicaud, Viviane; Pennacchio, Len A. et al.
System: The UNT Digital Library
An integral-equation theory for a self-interacting polymer adsorbed at an interface (open access)

An integral-equation theory for a self-interacting polymer adsorbed at an interface

None
Date: January 30, 2003
Creator: Cai, Jun & Prausnitz, J.M.
System: The UNT Digital Library
Molecular thermodynamics for some applications in biotechnology (open access)

Molecular thermodynamics for some applications in biotechnology

None
Date: January 30, 2003
Creator: Prausnitz, John M.
System: The UNT Digital Library
Bioactive glass coatings for orthopedic metallic implants (open access)

Bioactive glass coatings for orthopedic metallic implants

The objective of this work is to develop bioactive glass coatings for metallic orthopedic implants. A new family of glasses in the SiO2-Na2O-K2O-CaO-MgO-P2O5 system has been synthesized and characterized. The glass properties (thermal expansion, softening and transformation temperatures, density and hardness) are in line with the predictions of established empirical models. The optimized firing conditions to fabricate coatings on Ti-based and Co-Cr alloys have been determined and related to the glass properties and the interfacial reactions. Excellent adhesion to alloys has been achieved through the formation of 100-200 nm thick interfacial layers (Ti5Si3 on Ti-based alloys and CrOx on Co-Cr). Finally, glass coatings, approximately 100 mu m thick, have been fabricated onto commercial Ti alloy-based dental implants.
Date: June 30, 2003
Creator: Lopez-Esteban, Sonia; Saiz, Eduardo; Fujino, Sigheru; Oku, Takeo; Suganuma, Katsuaki & Tomsia, Antoni P.
System: The UNT Digital Library
Assessing I-Grid(TM) web-based monitoring for power quality and reliability benchmarking (open access)

Assessing I-Grid(TM) web-based monitoring for power quality and reliability benchmarking

This paper presents preliminary findings from DOEs pilot program. The results show how a web-based monitoring system can form the basis for aggregation of data and correlation and benchmarking across broad geographical lines. A longer report describes additional findings from the pilot, including impacts of power quality and reliability on customers operations [Divan, Brumsickle, Eto 2003].
Date: April 30, 2003
Creator: Divan, Deepak; Brumsickle, William & Eto, Joseph
System: The UNT Digital Library
Quantum interferometry in rho{sup 0} production in ultra-peripheral heavy ion collisions (open access)

Quantum interferometry in rho{sup 0} production in ultra-peripheral heavy ion collisions

In {rho}{sup 0} photoproduction in ultra-peripheral heavy ion collisions, either ion can be the photon emitter or the target. The two possibilities are indistinguishable, and they should be able to interfere, reducing {rho}{sup 0} production at low transverse momentum, p{sub T} < {h_bar}/<b>, where <b> is the median impact parameter. The two {rho}{sup 0} production points are separated by <b> {approx} 18-46 fm, while the {rho}{sup 0} decay before travelling 1 fm. The two decay points are well separated in spacetime, so the decays proceed independently and any interference must involve the final state {pi}{sup +}{pi}{sup -}. This requires a non-local wave function.
Date: December 30, 2003
Creator: Klein, Spencer R.
System: The UNT Digital Library
An overview of SuperLU: Algorithms, implementation, and userinterface (open access)

An overview of SuperLU: Algorithms, implementation, and userinterface

We give an overview of the algorithms, design philosophy,and implementation techniques in the software SuperLU, for solving sparseunsymmetric linear systems. In particular, we highlight the differencesbetween the sequential SuperLU (including its multithreaded extension)and parallel SuperLU_DIST. These include the numerical pivoting strategy,the ordering strategy for preserving sparsity, the ordering in which theupdating tasks are performed, the numerical kernel, and theparallelization strategy. Because of the scalability concern, theparallel code is drastically different from the sequential one. Wedescribe the user interfaces ofthe libraries, and illustrate how to usethe libraries most efficiently depending on some matrix characteristics.Finally, we give some examples of how the solver has been used inlarge-scale scientific applications, and the performance.
Date: September 30, 2003
Creator: Li, Xiaoye S.
System: The UNT Digital Library
Multi-strange baryon production in Au+Au collisions at {radical}s{sub NN} = 130 GeV (open access)

Multi-strange baryon production in Au+Au collisions at {radical}s{sub NN} = 130 GeV

The transverse mass spectra and mid-rapidity yields for {Xi}s and {Omega}s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to {pi}, K, p and {lambda}s.
Date: July 30, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Impurity distribution in Al{sub 2}O{sub 3} formed on FeCrAl alloy (open access)

Impurity distribution in Al{sub 2}O{sub 3} formed on FeCrAl alloy

None
Date: January 30, 2003
Creator: Hou, Peggy Y.; Zhang, X. F. & Cannon, R. M.
System: The UNT Digital Library
The New York Transmission Congestion Contract Market: Is It Truly Working Efficiently? (open access)

The New York Transmission Congestion Contract Market: Is It Truly Working Efficiently?

None
Date: June 30, 2003
Creator: Bartholomew, Emily S.; Siddiqui, Afzal S.; Marnay, Chris & Oren, Shmuel S.
System: The UNT Digital Library
Analyzing occupancy profiles from a lighting controls field study (open access)

Analyzing occupancy profiles from a lighting controls field study

Despite a number of published studies on the effectiveness of lighting controls in buildings, only one US study examines the occupancy patterns of building occupants. Occupancy profiles allow one to determine, for example, the probability that an office is occupied for each hour of the workday. Occupancy profiles are useful for many purposes including: (1) predicting the effectiveness of occupancy sensors for reducing peak demand, (2) evaluating the impact of human activity on building lighting and other electric loads and (3) providing lighting equipment manufacturers with detailed lighting operation data to help evaluate the impact of advanced lighting controls on equipment life. In this paper, we examine the occupancy profiles for 35 single person offices at a large office building in San Francisco and analyze the data to obtain average occupancy as a function of time of day. In addition, we analyzed the data to identify how the use of occupancy sensors may affect switching cycles and lamp life.
Date: April 30, 2003
Creator: Rubinstein, Francis; Colak, Nesrin; Jennings, Judith & Neils, Danielle
System: The UNT Digital Library
Searches at the Run II Tevatron Collider (open access)

Searches at the Run II Tevatron Collider

Some initial results based on 40-90 pb{sup -1} of integrated luminosity from Run II are presented for searches for new phenomena beyond the Standard Model, conducted at the upgraded Tevatron CDF and D0 experiments.
Date: September 30, 2003
Creator: Groer, Leslie Stevan
System: The UNT Digital Library
Lattice QCD production on commodity clusters at Fermilab (open access)

Lattice QCD production on commodity clusters at Fermilab

We describe the construction and results to date of Fermilab's three Myrinet-networked lattice QCD production clusters (an 80-node dual Pentium III cluster, a 48-node dual Xeon cluster, and a 128-node dual Xeon cluster). We examine a number of aspects of performance of the MILC lattice QCD code running on these clusters.
Date: September 30, 2003
Creator: Holmgren, D.; Singh, A.; Mackenzie, P.; Simone, J. & Gottlieb, Steven
System: The UNT Digital Library
Terabyte IDE RAID-5 Disk Arrays (open access)

Terabyte IDE RAID-5 Disk Arrays

High energy physics experiments are currently recording large amounts of data and in a few years will be recording prodigious quantities of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that exploit recent developments in commodity hardware. We report on tests of redundant arrays of integrated drive electronics (IDE) disk drives for use in offline high energy physics data analysis. IDE redundant array of inexpensive disks (RAID) prices now are less than the cost per terabyte of million-dollar tape robots! The arrays can be scaled to sizes affordable to institutions without robots and used when fast random access at low cost is important.
Date: September 30, 2003
Creator: al., David A. Sanders et
System: The UNT Digital Library
Testing V-A in top decay at CDF at squareroot s = 1.8 TeV (open access)

Testing V-A in top decay at CDF at squareroot s = 1.8 TeV

The structure of the tbW vertex can be probed by measuring the polarization of the W in t {yields} W + b {yields} l + v + b. The invariant mass of the lepton and b quark measures the W decay angle which in turn allows a comparison with polarizations expected from a V-A and V+A tbW vertex. We measure the fraction by rate of Ws produced with a V+A coupling in lieu of the Standard Model V-A to be f{sub V+A} = -0.21{sub -0.24}{sup +0.42}(stat) {+-} 0.21(sys). We assign a limit of f{sub V+A} < 0.80 {at} 95% CL. By combining this result with a complementary observable in the same data, we assign a limit of f{sub V+A} < 0.61 {at} 95% CL. From this CDF Run I preliminary result, we find no evidence for a non-standard Model tbW vertex.
Date: September 30, 2003
Creator: Kilminster, B.
System: The UNT Digital Library