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Nonlinear Statistical Signal Processing: A Particle Filtering Approach

Description: A introduction to particle filtering is discussed starting with an overview of Bayesian inference from batch to sequential processors. Once the evolving Bayesian paradigm is established, simulation-based methods using sampling theory and Monte Carlo realizations are discussed. Here the usual limitations of nonlinear approximations and non-gaussian processes prevalent in classical nonlinear processing algorithms (e.g. Kalman filters) are no longer a restriction to perform Bayesian inference. It … more
Date: September 19, 2007
Creator: Candy, J
Partner: UNT Libraries Government Documents Department
open access

STRANGENESS PRODUCTION AS A FUNCTION OF SYSTEM SIZE AND ENERGY OF RHIC.

Description: In this paper we report on strangeness measurements in p+p, Au+Au and Cu+Cu collisions at different energies in the STAR detector at RHIC. We will focus on two momentum regions in particular: Firstly we look at strangeness enhancement in A+A collisions with respect to p+p. These yields are dominated by low transverse momentum. We compare the enhancements from Au+Au and Cu+Cu data at {radical}s{sub NN} = 200 GeV with Pb+Pb data at {radical}s{sub NN} = 17.2 GeV and find that the enhancement does … more
Date: July 19, 2007
Creator: LAMONT,M.
Partner: UNT Libraries Government Documents Department
open access

Electron Beam Lifetime in SPEAR3: Measurement and Simulation

Description: In this paper we report on electron beam lifetime measurements as a function of scraper position, RF voltage and bunch fill pattern in SPEAR3. We then outline development of an empirical, macroscopic model using the beam-loss rate equation. By identifying the dependence of loss coefficients on accelerator and beam parameters, a numerically-integrating simulator can be constructed to compute beam decay with time. In a companion paper, the simulator is used to train a parametric, non-linear dynam… more
Date: December 19, 2007
Creator: Corbett, J.; Huang, X.; Lee, M. & Lui, P.
Partner: UNT Libraries Government Documents Department
open access

Fabrication of Pillar-Structured Thermal Neutron Detectors

Description: Pillar detector is an innovative solid state device structure that leverages advanced semiconductor fabrication technology to produce a device for thermal neutron detection. State-of-the-art thermal neutron detectors have shortcomings in achieving simultaneously high efficiency, low operating voltage while maintaining adequate fieldability performance. By using a 3-dimensional silicon PIN diode pillar array filled with isotopic boron 10, ({sup 10}B) a high efficiency device is theoretically pos… more
Date: November 19, 2007
Creator: Nikolic, R. J.; Conway, A. M.; Reinhardt, C. E.; Graff, R. T.; Wang, T. F.; Deo, N. et al.
Partner: UNT Libraries Government Documents Department
open access

Application of the TraPPE force field to predicting isothermal pressure-volume curves at high pressures and high temperatures

Description: Knowledge of the thermophysical properties of materials at extreme pressure and temperature conditions is essential for improving our understanding of many planetary and detonation processes. Significant gaps in what is known about the behavior of materials at high density and high temperature exist, largely due to the limitations and dangers of performing experiments at the necessary extreme conditions. Modeling these systems through the use of equations of state and particle-based simulation … more
Date: May 19, 2006
Creator: Eggimann, B L; Siepmann, J I & Fried, L E
Partner: UNT Libraries Government Documents Department
open access

Effects of Chromium(VI) and Chromium(III) on Desulfovibrio vulgaris Cells

Description: Desulfovibrio vulgaris ATCC 29579 is a well studied sulfate reducer that has known capabilities of reducing heavy metals and radionuclides, like chromium and uranium. Cultures grown in a defined medium (i.e. LS4D) had a lag period of approximately 40 h when exposed to 50 μMof Cr(VI). Substrate analysis revealed that although chromium is reduced within the first 5 h, growth does not resume for another 35 h. During this time, small amounts of lactate are still utilized but the reduction of sulfat… more
Date: April 19, 2007
Creator: Clark, M.E.; Klonowska, A.; Thieman, S.B.; Giles, B.; Wall, J.D. & Fields, and M.W.
Partner: UNT Libraries Government Documents Department
open access

Empirical evidence for a recent slowdown in irrigation-induced cooling

Description: Understanding the influence of past land use changes on climate is needed to improve regional projections of future climate change and inform debates about the tradeoffs associated with land use decisions. The effects of rapid expansion of irrigated area in the 20th century has remained unclear relative to other land use changes, such as urbanization, that affected a similar total land area. Using spatial and temporal variations in temperature and irrigation extent observed in California, we sh… more
Date: January 19, 2007
Creator: Bonfils, C & Lobell, D
Partner: UNT Libraries Government Documents Department
open access

Birth of Massive Black Hole Binaries

Description: If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BH… more
Date: November 19, 2007
Creator: Colpi, M.; Dotti, M.; Mayer, L. & Kazantzidis, S.
Partner: UNT Libraries Government Documents Department
open access

New cubic phase of lithium nitride to 200 GPa

Description: We present a new cubic ({gamma}) Li{sub 3}N phase discovered above 40({+-}5) GPa. Structure and electronic bands are examined at high pressure with synchrotron x-ray diffraction and inelastic x-ray scattering in a diamond anvil cell, and also with first-principles calculations. We observe a dramatic band-gap widening and volume collapse at the phase transition. {gamma}-Li{sub 3}N remains extremely stable and ionic to 200 GPa, with predicted metallization near 8 TPa. The high structural stabilit… more
Date: July 19, 2005
Creator: Lazicki, A.; Maddox, B.; Evans, W.; Yoo, C. S.; McMahan, A. K.; Pickett, W. E. et al.
Partner: UNT Libraries Government Documents Department
open access

GENERATION OF SUBPICOSECOND X-RAY PULSES IN STORAGE RINGS

Description: Supicosecond x-ray pulses are routinely produced at ALS,BESSY and SLS with slicing technique and used in pump-probe experimentswith controlled delay between laser pump pulses and x-ray probe pulses.New development aiming for a production of a subpicosecond x-ray pulsesusing rf orbit deflection technique is under way at APS. Both techniqueswill be reviewed here.
Date: June 19, 2007
Creator: Zholents, Alexander A.
Partner: UNT Libraries Government Documents Department
open access

Performance and Accuracy of LAPACK's Symmetric TridiagonalEigensolvers

Description: We compare four algorithms from the latest LAPACK 3.1 release for computing eigenpairs of a symmetric tridiagonal matrix. These include QR iteration, bisection and inverse iteration (BI), the Divide-and-Conquer method (DC), and the method of Multiple Relatively Robust Representations (MR). Our evaluation considers speed and accuracy when computing all eigenpairs, and additionally subset computations. Using a variety of carefully selected test problems, our study includes a variety of today's co… more
Date: April 19, 2007
Creator: Demmel, Jim W.; Marques, Osni A.; Parlett, Beresford N. & Vomel, Christof
Partner: UNT Libraries Government Documents Department
open access

Investigation of Charge Transport Properties of CdZnTe Detectors with Synchrotron X-ray Radiation

Description: Various internal defects, such as Te inclusions, twin boundaries, dislocation, etc., are prevalent in as-grown CdZnTe (CZT) crystals, which affect the charge transport properties of CZT crystals and, therefore, worsen the performance of CZT detectors. In order to develop high quality CZT detectors, it is imperative to clarify the effects of internal defects on the charge transport properties of CZT. Simple flood illumination with nuclear radiation source cannot reveal the nature of highly local… more
Date: October 19, 2008
Creator: Yang, G.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Hossain, A. & James, R. B.
Partner: UNT Libraries Government Documents Department
open access

An optimal point spread function subtraction algorithm for high-contrast imaging: a demonstration with angular differential imaging

Description: Direct imaging of exoplanets is limited by bright quasi-static speckles in the point spread function (PSF) of the central star. This limitation can be reduced by subtraction of reference PSF images. We have developed an algorithm to construct an optimal reference PSF image from an arbitrary set of reference images. This image is built as a linear combination of all available images and is optimized independently inside multiple subsections of the image to ensure that the absolute minimum residu… more
Date: September 19, 2006
Creator: Lafreniere, D; Marois, C; Doyon, R; Artigau, E & Nadeau, D
Partner: UNT Libraries Government Documents Department
open access

A comparison of DNA damage probes in two HMEC lines with X-irradiation

Description: In this study, we investigated {gamma}H2AX{sup ser139} and 53BP1{sup ser25}, DNA damage pathway markers, to observe responses to radiation insult. Two Human Mammary Epithelial Cell (HMEC) lines were utilized to research the role of immortalization in DNA damage marker expression, HMEC HMT-3522 (S1) with an infinite lifespan, and a subtype of HMEC 184 (184V) with a finite lifespan. Cells were irradiated with 50 cGy X-rays, fixed with 4% paraformaldehyde after 1 hour repair at 37 C, and processed… more
Date: January 19, 2007
Creator: Wisnewski, Christy L.; Bjornstad, Kathleen A.; Rosen, ChristoperJ.; Chang, Polly Y. & Blakely, Eleanor A.
Partner: UNT Libraries Government Documents Department
open access

Dynamics of Converging Laser-Created Plasmas in Semi-Cylindrical Cavities Studied using Soft X-Ray Laser Interferometry

Description: The evolution of dense aluminum and carbon plasmas produced by laser irradiation of 500 {micro}m diameter semi-cylindrical targets was studied using soft x-ray laser interferometry. Plasmas created heating the cavity walls with 120 picosecond duration optical laser pulses of {approx} 1 x 10{sup 12} W cm{sup -2} peak intensity were observed to expand and converge on axis to form a localized high density plasma region. Electron density maps were measured using a 46.9 nm wavelength tabletop capill… more
Date: September 19, 2007
Creator: Purvis, M. A.; Grava, J.; Filevich, J.; Marconi, M.; Dunn, J.; Moon, S. J. et al.
Partner: UNT Libraries Government Documents Department
open access

CARBON NANOMATERIALS AS CATALYSTS FOR HYDROGEN UPTAKE AND RELEASE IN NAALH4

Description: A synergistic approach involving experiment and first-principles theory not only shows that carbon nanostructures can be used as catalysts for hydrogen uptake and release in complex metal hydrides such as sodium alanate, NaAlH{sub 4}, but also provides an unambiguous understanding of how the catalysts work. The stability of NaAlH{sub 4} originates from the charge transfer from Na to the AlH{sub 4} moiety, resulting in an ionic bond between Na{sup +} and AlH{sub 4}{sup -} and a covalent bond bet… more
Date: June 19, 2008
Creator: Berseth, P; Ragaiy Zidan, R & Andrew Harter, A
Partner: UNT Libraries Government Documents Department
open access

Plasma Interactions in Laser Irradiated Semi-Cylindrical Cavities Studied with Soft X-Ray Interferometry Using a Capillary Discharge Laser

Description: Soft x-ray interferometry was used to measure the evolution of dense converging plasmas created by laser irradiation of 500 {micro}m diameter semi-cylindrical carbon targets. Optical laser pulses with an intensity of {approx} 1 x 10{sup 12} W cm{sup -2} and 120 ps duration were used to heat the surface of the cavities. The dense plasma formed expands from the walls converging slightly off the semi-cylinder's axis, giving rise to a bright localized high density plasma region. A sequence of elect… more
Date: September 19, 2007
Creator: Purvis, M. A.; Grava, J.; Filevich, J.; Marconi, M.; Rocca, J. J.; Moon, S. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Epigenetic reversion of breast carcinoma phenotype is accompanied by DNA sequestration

Description: The importance of microenvironment and context in regulation of tissue-specific genes is finally well established. DNA exposure to, or sequestration from, nucleases can be used to detect differences in higher order chromatin structure in intact cells without disturbing cellular or tissue architecture. To investigate the relationship between chromatin organization and tumor phenotype, we utilized an established 3-D assay where normal and malignant human breast cells can be easily distinguished b… more
Date: July 19, 2006
Creator: Sandal, Tone; Valyi-Nagy, Klara; Spencer, Virginia A.; Folberg,Robert; Bissell, Mina J. & Maniotis, Andrew J.
Partner: UNT Libraries Government Documents Department
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