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On the occasion of the inauguration of Balenciaga and His Legacy: Haute Couture from the Texas Fashion Collection (open access)

On the occasion of the inauguration of Balenciaga and His Legacy: Haute Couture from the Texas Fashion Collection

Article and gallery of photographs from the gala premiere for the "Balenciaga and His Legacy: Haute Couture from the Texas Fashion Collection" exhibit held at the Meadows Museum in Dallas.
Date: March 24, 2007
Creator: Adams, Sharon
System: The UNT Digital Library
The EAR-motif of the Cys2/His2-type Zinc Finger Protein Zat7 Plays a Key Role in the Defense Response of Arabidopsis to Salinity Stress (open access)

The EAR-motif of the Cys2/His2-type Zinc Finger Protein Zat7 Plays a Key Role in the Defense Response of Arabidopsis to Salinity Stress

Article reporting that transgenic Arabidopsis plants constitutively expressing the Cys2/His2 zinc finger protein Zat7 have suppressed growth and are more tolerant to salinity stress. Findings demonstrate that the EAR-domain of Cys2/His2-type zinc finger proteins plays a key role in the defense response of Arabidopsis to abiotic stresses.
Date: March 23, 2007
Creator: Ciftci-Yilmaz, Sultan; Morsy, Mustafa R.; Song, Luhua; Coutu, Alicia; Krizek, Beth A.; Lewis, Michael W. et al.
System: The UNT Digital Library
Proof of Principle Experiments That Demonstrate Utility of Cocktail Hohlraums for Indirect Drive Ignition (open access)

Proof of Principle Experiments That Demonstrate Utility of Cocktail Hohlraums for Indirect Drive Ignition

None
Date: March 7, 2007
Creator: Jones, O. S.; Schein, J.; Rosen, M.. D.; Suter, L. J.; Wallace, R. J.; Dewald, E. L. et al.
System: The UNT Digital Library
Wheat phytotoxicity from arsenic and cadmium separately and together in solution culture and in a calcareous soil (open access)

Wheat phytotoxicity from arsenic and cadmium separately and together in solution culture and in a calcareous soil

The toxicity effect of two deleterious elements of arsenic (As) and cadmium (Cd) (individually or in combination) on root elongation of wheat seedlings (Triticum aestivum, L.) were investigated both in hydroponics and in soils freshly spiked with the toxic elements. Median effective concentration (EC{sub 50}) and non-observed effect concentration (NOEC) were used to investigate the toxic thresholds and potencies of the two elements. The EC{sub 50} for As was 0.97 {mu}M in hydroponics and 196 mg {center_dot} kg{sup -1} in soil, and 4.32 {mu}M and 449 mg {center_dot} kg{sup -1} for Cd, respectively. Toxic unit (TU) and additive index (AI) concepts were introduced to determine the combined outcomes, and different behaviors were obtained: synergism in solution culture (EC{sub 50mix} = 0.36 TU{sub mix} and AI: 1.76) and antagonism in soil experiments (EC{sub 50mix} = 1.49 TU{sub mix} and AI: -0.33). Furthermore, the data of soil bioavailable As and Cd can not explain the discrepancy between the results derived from soil and hydroponics experiments.
Date: March 5, 2007
Creator: Cao, Q.; Hu, Q.; Khan, S.; Wang, Z.; Lin, A.; Du, X. et al.
System: The UNT Digital Library
Dose, exposure time, and resolution in Serial X-ray Crystallography (open access)

Dose, exposure time, and resolution in Serial X-ray Crystallography

Using detailed simulation and analytical models, the exposure time is estimated for serial crystallography, where hydrated laser-aligned proteins are sprayed across a continuous synchrotron beam. The resolution of X-ray diffraction microscopy is limited by the maximum dose that can be delivered prior to sample damage. In the proposed Serial Crystallography method, the damage problem is addressed by distributing the total dose over many identical hydrated macromolecules running continuously in a single-file train across a continuous X-ray beam, and resolution is then limited only by the available fluxes of molecules and X-rays. Orientation of the diffracting molecules is achieved by laser alignment. We evaluate the incident X-ray fluence (energy/area) required to obtain a given resolution from (1) an analytical model, giving the count rate at the maximum scattering angle for a model protein, (2) explicit simulation of diffraction patterns for a GroEL-GroES protein complex, and (3) the frequency cut off of the transfer function following iterative solution of the phase problem, and reconstruction of a density map in the projection approximation. These calculations include counting shot noise and multiple starts of the phasing algorithm. The results indicate the number of proteins needed within the beam at any instant for a given …
Date: March 22, 2007
Creator: Starodub, D.; Rez, P.; Hembree, G.; Howells, M.; Shapiro, D.; Chapman, H. N. et al.
System: The UNT Digital Library
FEL Design Studies at LBNL: Activities and Plans (open access)

FEL Design Studies at LBNL: Activities and Plans

LBNL staff are currently pursuing R&D for future x-ray FELs, and participate in two FEL construction projects. Our strategy is to address the most fundamental challenges, which are the cost-drivers and performance limitations of FEL facilities. An internally funded R&D program is aimed at investigating accelerator physics and technologies in three key areas: (1) Theoretical study, modeling, and experimental development of low emittance, high quantum efficiency cathodes; (2) Design studies of electron beam delivery systems, including emittance manipulations, high-resolution modeling of 6-D phase space, and low-emittance beam transport; and (3) Design studies of optical manipulations of electron beams for seeded and SASE FELs, providing short x-ray pulses of variable duration, synchronous with the seed and pump laser sources, and also long transform-limited pulses with a narrow bandwidth. Design studies of means for production of attosecond x-ray pulses at various wavelengths. We are collaborators in the FERMI{at}Elettra seeded FEL facility under construction at Sincrotrone Trieste, Italy, participating in accelerator design and FEL physics studies, and mechanical and electrical engineering. We are participating in the LCLS project at SLAC, implementing our design of stabilized timing and synchronization systems. Here we outline our long-term objectives, and current activities.
Date: March 1, 2007
Creator: Corlett, John N.; Fawley, W.; Lidia, S.; Padmore, H.; Penn, G.; Pogorelov, I. et al.
System: The UNT Digital Library
Recent results from the Berkeley 0.3-NA microfield exposure tool (open access)

Recent results from the Berkeley 0.3-NA microfield exposure tool

Operating as a SEMATECH resist test center, the Berkeley 0.3-NA EUV microfield exposure tool continues to play a crucial role in the advancement of EUV resists and masks. Here we present recent resist-characterization results from the tool as well as tool-characterization data. In particular we present lithographic-based aberration measurements demonstrating the long-term stability of the tool. We also describe a recent upgrade to the tool which involved redesign of the programmable coherence illuminator to provide improved field uniformity as well as a programmable field size.
Date: March 1, 2007
Creator: Naulleau, Patrick; Anderson, Christopher N.; Dean, Kim; Denham, Paul; Goldberg, Kenneth A.; Hoef, Brian et al.
System: The UNT Digital Library
K(alpha) X-ray Emission Spectra from Highly Charged Fe Ions in EBIT (open access)

K(alpha) X-ray Emission Spectra from Highly Charged Fe Ions in EBIT

A detailed spectral model has been developed for the computer simulation of the 2p {yields} 1s K{alpha} X-ray emission from highly charged Fe ions in the Electron Beam Ion Trap (EBIT). The spectral features of interest occur in the range from 1.84 {angstrom} to 1.94 {angstrom}. The fundamental radiative emission processes associated with radiationless electron capture or dielectronic recombination, inner-shell electron collisional excitation, and inner-shell electron collisional ionization are taken in account. For comparison, spectral observations and simulations for high-temperature magnetic-fusion (Tokamak) plasmas are reviewed. In these plasmas, small departures from steady-state corona-model charge-state distributions can occur due to ion transport processes, while the assumption of equilibrium (Maxwellian) electron energy distributions is expected to be valid. Our investigations for EBIT have been directed at the identification of spectral features that can serve as diagnostics of extreme non-equilibrium or transient-ionization conditions, and allowance has been made for general (non-Maxwellian) electron energy distributions. For the precise interpretation of the high-resolution X-ray observations, which may involve the analysis of blended spectral features composed of many lines, it has been necessary to take into account the multitude of individual fine-structure components of the K{alpha} radiative transitions in the ions from Fe XVIII to Fe …
Date: March 29, 2007
Creator: Jacobs, V & Beiersdorfer, P
System: The UNT Digital Library
MiniBooNE (open access)

MiniBooNE

MiniBooNE is a short baseline neutrino experiment designed to confirm or refute the LSND observed excess of electron anti neutrinos in a muon anti neutrino beam. The experimental setup, data samples, and oscillation fit method are discussed. Although the result was not public at the time of the talk, MiniBooNE has since published results, which are discussed briefly as well.
Date: March 1, 2007
Creator: Mahn, Kendall Brianna Mcconnel
System: The UNT Digital Library
Theory Challenges of the Accelerating Universe (open access)

Theory Challenges of the Accelerating Universe

The accelerating expansion of the universe presents an exciting, fundamental challenge to the standard models of particle physics and cosmology. I highlight some of the outstanding challenges in both developing theoretical models and interpreting without bias the observational results from precision cosmology experiments in the next decade that will return data to help reveal the nature of the new physics. Examples given focus on distinguishing a new component of energy from a new law of gravity, and the effect of early dark energy on baryon acoustic oscillations.
Date: March 5, 2007
Creator: Linder, Eric V.
System: The UNT Digital Library
A Three-Year Study of Ichyoplankton in Coastal Plains Reaches of the Savannah River Site and its Tributaries (open access)

A Three-Year Study of Ichyoplankton in Coastal Plains Reaches of the Savannah River Site and its Tributaries

Altering flow regimes of rivers has large effects on native floras and faunas because native species are adapted to the natural flow regime, many species require lateral connectivity with floodplain habitat for feeding or spawning, and the change in regime often makes it possible for invasive species to replace natives (Bunn & Arthington 2002). Floodplain backwaters, both permanent and temporary, are nursery areas for age 0+ fish and stable isotope studies indicate that much of the productivity that supports fish larvae is autochthonous to these habitats (Herwig et al. 2004). Limiting access by fish to floodplain habitat for feeding, spawning and nursery habitat is one of the problems noted with dams that regulate flow in rivers and is considered to be important as an argument to remove dams and other flow regulating structures from rivers (Shuman 1995; Bednarek 2001). While there have been a number of studies in the literature about the use of floodplain habitat for fish reproduction (Copp 1989; Killgore & Baker 1996; Humphries, et al. 1999; Humphries and Lake 2000; Crain et al. 2004; King 2004) there have been only a few studies that examined this aspect of stream ecology in more than a cursory way. The …
Date: March 5, 2007
Creator: Martin, D.
System: The UNT Digital Library
Segue between Favorable and Unfavorable Solvation (open access)

Segue between Favorable and Unfavorable Solvation

Solvation of small and large clusters are studied by simulation, considering a range of solvent-solute attractive energy strengths. Over a wide range of conditions, both for solvation in the Lennard-Jones liquid and in the SPC model of water, it is shown that the mean solvent density varies linearly with changes in solvent-solute adhesion or attractive energy strength. This behavior is understood from the perspective of Weeks theory of solvation [Ann. Rev. Phys. Chem. 2002, 53, 533] and supports theories based upon that perspective.
Date: March 21, 2007
Creator: Maibaum, Lutz & Chandler, David
System: The UNT Digital Library
Confinement and Local Transport in the National Spherical Torus Experiment NSTX (open access)

Confinement and Local Transport in the National Spherical Torus Experiment NSTX

NSTX operates at low aspect ratio (R/a~1.3) and high beta (up to 40%), allowing tests of global confinement and local transport properties that have been established from higher aspect ratio devices. NSTX plasmas are heated by up to 7 MW of deuterium neutral beams with preferential electron heating as expected for ITER. Confinement scaling studies indicate a strong ΒΤ dependence, with a current dependence that is weaker than that observed at higher aspect ratio. Dimensionless scaling experiments indicate a strong increase of confinement with decreasing collisionality and a weak degradation with beta. The increase of confinement with ΒΤ is due to reduced transport in the electron channel, while the improvement with plasma current is due to reduced transport in the ion channel related to the decrease in the neoclassical transport level. Improved electron confinement has been observed in plasmas with strong reversed magnetic shear, showing the existence of an electron internal transport barrier (eITB). The development of the eITB may be associated with a reduction in the growth of microtearing modes in the plasma core. Perturbative studies show that while L-mode plasmas with reversed magnetic shear and an eITB exhibit slow changes of LΤe across the profile after the pellet …
Date: March 15, 2007
Creator: Kaye, S. M.; Stutman, D.; Tritz, K.; Yuh, H.; Bell, M. G.; Bell, R. E. et al.
System: The UNT Digital Library
Book Review Geostatistical Analysis of Compositional Data (open access)

Book Review Geostatistical Analysis of Compositional Data

Compositional data are represented as vector variables with individual vector components ranging between zero and a positive maximum value representing a constant sum constraint, usually unity (or 100 percent). The earth sciences are flooded with spatial distributions of compositional data, such as concentrations of major ion constituents in natural waters (e.g. mole, mass, or volume fractions), mineral percentages, ore grades, or proportions of mutually exclusive categories (e.g. a water-oil-rock system). While geostatistical techniques have become popular in earth science applications since the 1970s, very little attention has been paid to the unique mathematical properties of geostatistical formulations involving compositional variables. The book 'Geostatistical Analysis of Compositional Data' by Vera Pawlowsky-Glahn and Ricardo Olea (Oxford University Press, 2004), unlike any previous book on geostatistics, directly confronts the mathematical difficulties inherent to applying geostatistics to compositional variables. The book righteously justifies itself with prodigious referencing to previous work addressing nonsensical ranges of estimated values and error, spurious correlation, and singular cross-covariance matrices.
Date: March 26, 2007
Creator: Carle, S F
System: The UNT Digital Library
Eclipsing binary stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample (open access)

Eclipsing binary stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample

We present a new sample of 4634 eclipsing binary stars in the Large Magellanic Cloud (LMC), expanding on a previous sample of 611 objects and a new sample of 1509 eclipsing binary stars in the Small Magellanic Cloud (SMC), that were identified in the light curve database of the MACHO project. We perform a cross correlation with the OGLE-II LMC sample, finding 1236 matches. A cross correlation with the OGLE-II SMC sample finds 698 matches. We then compare the LMC subsamples corresponding to center and the periphery of the LMC and find only minor differences between the two populations. These samples are sufficiently large and complete that statistical studies of the binary star populations are possible.
Date: March 29, 2007
Creator: Faccioli, L.; Alcock, C.; Cook, K.; Prochter, G.; Protopapas, P. & Syphers, D.
System: The UNT Digital Library
Linear Multifrequency-Grey Acceleration Recast for Preconditioned Krylov Iterations (open access)

Linear Multifrequency-Grey Acceleration Recast for Preconditioned Krylov Iterations

None
Date: March 19, 2007
Creator: Morel, J E; Yang, T B & Warsa, J S
System: The UNT Digital Library
InN Nanorods Grown on Different Planes of Al2O3 (open access)

InN Nanorods Grown on Different Planes of Al2O3

None
Date: March 10, 2007
Creator: Liliental-Weber, Z.; Park, H.J.; Mangum, J.; Anderson, T. & Kryliouk, O.
System: The UNT Digital Library
Non-destructive Identification of Individual Leukemia Cells by Optical Trapping Raman Spectroscopy (open access)

Non-destructive Identification of Individual Leukemia Cells by Optical Trapping Raman Spectroscopy

Currently, a combination of technologies is typically required to assess the malignancy of cancer cells. These methods often lack the specificity and sensitivity necessary for early, accurate diagnosis. Here we demonstrate using clinical samples the application of laser trapping Raman spectroscopy as a novel approach that provides intrinsic biochemical markers for the noninvasive detection of individual cancer cells. The Raman spectra of live, hematopoietic cells provide reliable molecular fingerprints that reflect their biochemical composition and biology. Populations of normal T and B lymphocytes from four healthy individuals, and cells from three leukemia patients were analyzed, and multiple intrinsic Raman markers associated with DNA and protein vibrational modes have been identified that exhibit excellent discriminating power for cancer cell identification. A combination of two multivariate statistical methods, principal component analysis (PCA) and linear discriminant analysis (LDA), was used to confirm the significance of these markers for identifying cancer cells and classifying the data. The results indicate that, on average, 95% of the normal cells and 90% of the patient cells were accurately classified into their respective cell types. We also provide evidence that these markers are unique to cancer cells and not purely a function of differences in their cellular activation.
Date: March 5, 2007
Creator: Chan, J W; Taylor, D S; Lane, S; Zwerdling, T; Tuscano, J & Huser, T
System: The UNT Digital Library
Coupled Reservoir-Geomechanical Analysis of the Potential for Tensile and Shear Failure Associated With CO2 Injection in Multilayered Reservoir-Caprock Systems (open access)

Coupled Reservoir-Geomechanical Analysis of the Potential for Tensile and Shear Failure Associated With CO2 Injection in Multilayered Reservoir-Caprock Systems

Coupled reservoir-geomechanical simulations were conductedto study the potential for tensile and shear failure e.g., tensilefracturing and shear slip along pre-existing fractures associated withunderground CO2 injection in a multilayered geological system. Thisfailure analysis aimed to study factors affecting the potential forbreaching a geological CO2 storage system and to study methods forestimating the maximum CO2 injection pressure that could be sustainedwithout causing such a breach. We pay special attention to geomechanicalstress changes resulting from upward migration of the CO2 and how theinitial stress regime affects the potential for inducing failure. Weconclude that it is essential to have an accurate estimate of thethree-dimensional in situ stress field to support the design andperformance assessment of a geological CO2 injection operation. Moreover,we also conclude that it is important to consider mechanical stresschanges that might occur outside the region of increased reservoir fluidpressure (e.g., in the overburden rock) between the CO2-injectionreservoir and the ground surface.
Date: March 27, 2007
Creator: Rutqvist, J.; Birkholzer, J. T. & Tsang, C.-F.
System: The UNT Digital Library
A Multigroup diffusion Solver Using Pseudo Transient Continuation for a Radiaiton-Hydrodynamic Code with Patch-Based AMR (open access)

A Multigroup diffusion Solver Using Pseudo Transient Continuation for a Radiaiton-Hydrodynamic Code with Patch-Based AMR

We present a scheme to solve the nonlinear multigroup radiation diffusion (MGD) equations. The method is incorporated into a massively parallel, multidimensional, Eulerian radiation-hydrodynamic code with adaptive mesh refinement (AMR). The patch-based AMR algorithm refines in both space and time creating a hierarchy of levels, coarsest to finest. The physics modules are time-advanced using operator splitting. On each level, separate 'level-solve' packages advance the modules. Our multigroup level-solve adapts an implicit procedure which leads to a two-step iterative scheme that alternates between elliptic solves for each group with intra-cell group coupling. For robustness, we introduce pseudo transient continuation ({Psi}tc). We analyze the magnitude of the {Psi}tc parameter to ensure positivity of the resulting linear system, diagonal dominance and convergence of the two-step scheme. For AMR, a level defines a subdomain for refinement. For diffusive processes such as MGD, the refined level uses Dirichet boundary data at the coarse-fine interface and the data is derived from the coarse level solution. After advancing on the fine level, an additional procedure, the sync-solve (SS), is required in order to enforce conservation. The MGD SS reduces to an elliptic solve on a combined grid for a system of G equations, where G is the …
Date: March 2, 2007
Creator: Shestakov, A I & Offner, S R
System: The UNT Digital Library
Organic carbon distribution, speciation, and elementalcorrelations within soil microaggregates: applications of STXM and NEXAFSspectroscopy (open access)

Organic carbon distribution, speciation, and elementalcorrelations within soil microaggregates: applications of STXM and NEXAFSspectroscopy

Soils contain the largest inventory of organic carbon on the Earth's surface. Therefore, it is important to understand how soil organic carbon (SOC) is distributed in soils. This study directly measured SOC distributions within soil microaggregates and its associations with major soil elements from three soil groups (Phaeozem, Cambisol, and Ultisol), using scanning transmission X-ray microscopy (STXM) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at a spatial resolution of 30 nm. Unlike previous studies, small intact soil microaggregates were examined directly in order to avoid preparatory procedures that might alter C speciation. We found that SOC exists as distinct particles (tens to hundreds of nm) and as ubiquitous thin coatings on clay minerals and iron-oxides coatings. The distinct SOC particles have higher fractions of aromatic C than the coatings. NEXAFS spectra of the C coatings within individual microaggregates were relatively similar. In the Phaeozem soil, the pervasive spectral features were those of phenolic and carboxylic C, while in the Cambisol soil the most common spectral feature was the carboxyl peak. The Ultisol soil displayed a diffuse distribution of aromatic, phenolic, and carboxylic C peaks over all surfaces. In general, a wide range of C functional groups coexist within individual …
Date: March 15, 2007
Creator: Wan, Jiamin; Tyliszczak, Tolek & Tokunaga, Tetsu K.
System: The UNT Digital Library
The Life-cycle of Operons (open access)

The Life-cycle of Operons

Operons are a major feature of all prokaryotic genomes, buthow and why operon structures vary is not well understood. To elucidatethe life-cycle of operons, we compared gene order between Escherichiacoli K12 and its relatives and identified the recently formed anddestroyed operons in E. coli. This allowed us to determine how operonsform, how they become closely spaced, and how they die. Our findingssuggest that operon evolution may be driven by selection on geneexpression patterns. First, both operon creation and operon destructionlead to large changes in gene expression patterns. For example, theremoval of lysA and ruvA from ancestral operons that contained essentialgenes allowed their expression to respond to lysine levels and DNAdamage, respectively. Second, some operons have undergone acceleratedevolution, with multiple new genes being added during a brief period.Third, although genes within operons are usually closely spaced becauseof a neutral bias toward deletion and because of selection against largeoverlaps, genes in highly expressed operons tend to be widely spacedbecause of regulatory fine-tuning by intervening sequences. Althoughoperon evolution may be adaptive, it need not be optimal: new operonsoften comprise functionally unrelated genes that were already inproximity before the operon formed.
Date: March 15, 2007
Creator: Price, Morgan N.; Arkin, Adam P. & Alm, Eric J.
System: The UNT Digital Library
Flashing Slurry Releases (open access)

Flashing Slurry Releases

The Hanford K Basin Closure Project involves the retrieval, transfer and processing of radioactive contaminated slurries containing partially corroded spent nuclear fuel from the K Basin spent fuel pools. The spent fuel is primarily metallic fuel from the operation of the Hanford reactors. The Sludge Treatment Project is being designed to treat and package this material in preparation for ultimate disposal. The processing of the contaminated slurries includes further corrosion of the remaining uncorroded uranium metal in a large heated vessel to form a more stable metal oxide for packaging and storage.
Date: March 14, 2007
Creator: Schmitt, Bruce E. & Young, Jonathan
System: The UNT Digital Library
A qualitative assessment of microclimatic perturbations in atunnel (open access)

A qualitative assessment of microclimatic perturbations in atunnel

Understanding microclimate dynamics in tunnels is importantfor designing and maintaining underground facilities. For example, in thegeological disposal of radioactive materials, condensation of vaporshould be minimized as it can accelerate waste package corrosion andradionuclide release. While microclimate dynamics are known to bedominated by the advection of heat and moisture, additional factors mayalso be important, such as the presence of fractures or faults. Wepresent a relatively inexpensive method to assess microclimaticperturbations within a tunnel. By combining standard temperature andrelative humidity sensors with low-cost sensors designed to detectchanges in condensation, we monitored microclimate dynamics along atunnel at the proposed geological repository at Yucca Mountain, Nevada.We observed significant differences in the pattern of condensation in afaulted zone relative to that of a nonfaulted zone, suggesting that themicroclimate dynamics of excavated cavities in fractured, partiallysaturated rocks can be highly complex.
Date: March 1, 2007
Creator: Salve, R. & Kowalsky, M. B.
System: The UNT Digital Library