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2003

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Articles 1141 - 1170 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Threshold Electrodisintegration Of 3he, R S. Hicks, A Hotta, S Churchwell, X Jiang, Gerald Alvin Peterson, J Shaw, B Asavapibhop, M C. Berisso, P E. Bosted, K Burchesky, R A. Miskimen, S E. Rock Jun 2003

Threshold Electrodisintegration Of 3he, R S. Hicks, A Hotta, S Churchwell, X Jiang, Gerald Alvin Peterson, J Shaw, B Asavapibhop, M C. Berisso, P E. Bosted, K Burchesky, R A. Miskimen, S E. Rock

Gerald Alvin Peterson

Cross sections were measured for the near-threshold electrodisintegration of 3He at momentum transfer values of q=2.4, 4.4, and 4.7fm-1. From these and prior measurements the transverse and longitudinal response functions RT and RL were deduced. Comparisons are made against previously published and new nonrelativistic A=3 calculations using the best available nucleon-nucleon NN potentials. In general, for q<2fm-1 these calculations accurately predict the threshold electrodisintegration of 3He. Agreement at increasing q demands consideration of two-body terms, but discrepancies still appear at the highest momentum transfers probed, perhaps due to the neglect of relativistic dynamics, or to the underestimation of high-momentum wave-function components.


Organization Of The Devils Hole Workshop, Irene Farnham Jun 2003

Organization Of The Devils Hole Workshop, Irene Farnham

Publications (YM)

The Harry Reid Center for Environmental Studies (HRC) at the University of Nevada, Las Vegas (UNLV) was tasked to organize the Devils Hole Workshop in Furnace Creek Death Valley, CA on May 21 – 23, 2003. This Conference is designed to report current research results and to bring the scientific community, as well as the general public, up to date on research relevant to the Death Valley Regional Flow System (DVRFS). The Devils Hole Workshop is beneficial to the DOE because it provides the opportunity to DOE technical task leaders and Bechtel SAIC (BSC) representatives to present the research currently …


On Using Fast Exponentiation Algorithm In Pdas (Or: How Secure Is The Discrete Logarithm Problem Assumption In Pdas?) , Willy Susilo, Jianyong Huang, Jennifer Seberry Jun 2003

On Using Fast Exponentiation Algorithm In Pdas (Or: How Secure Is The Discrete Logarithm Problem Assumption In Pdas?) , Willy Susilo, Jianyong Huang, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Personal Digital Assistants (PDAs) are the miniature of normal size PCs, with a very limited computational power. In this paper, we investigate the security of PDAs when they are used to perform some cryptographic applications. In our context, we investigate the computation y = g' (mod p), for a prime p, which is believed to be secure in the sense of the Discrete Logarithm Problem (DLP) assumption. To be more precise, knowing only p, g and y, it is hard to derive x. We note that this computation is the most important operation in most cryptographic algorithms. However, due to …


Iteration Methods For Approximating The Lowest Order Energy Eigenstate Of A Given Symmetry For One- And Two-Dimensional Systems, Chad Everett Junkermeier Jun 2003

Iteration Methods For Approximating The Lowest Order Energy Eigenstate Of A Given Symmetry For One- And Two-Dimensional Systems, Chad Everett Junkermeier

Theses and Dissertations

Using the idea that a quantum mechanical system drops to its ground state as its temperature goes to absolute zero several operators are devised to enable the approximation of the lowest order energy eigenstate of a given symmetry; as well as an approximation to the energy eigenvalue of the same order.


Some Issues On Time Varying Risk Premium In Arch-M Model., Samarjit Das Dr. Jun 2003

Some Issues On Time Varying Risk Premium In Arch-M Model., Samarjit Das Dr.

Doctoral Theses

Since the 1970's it has been observed in many economies that financial and macroeconomic variables like equity prices, treasury bill rates and exchange rates have become more and more volatile in nature. This may be due tumor flexible monetary policies pursued in these countries as well as due to their increasing exposure towards various international developments. Accordingly, economic agents are facing increasingly more and more risky environment. Re- searchers as well as professional economists in the area of capital and business finance have, therefore, been increasingly attracted in recent years towards studying the effect of risk and uncertainty on asset …


Methyl And T-Butyl Group Reorientation In Planar Aromatic Solids: Low-Frequency Nuclear Magnetic Resonance Relaxometry And X-Ray Diffraction, Peter A. Beckmann, Carylon Buser, Kathleen Gullifer, Frank B. Mallory, Clelia W. Mallory, Gene M. Rossi, Arnold L. Rheingold Jun 2003

Methyl And T-Butyl Group Reorientation In Planar Aromatic Solids: Low-Frequency Nuclear Magnetic Resonance Relaxometry And X-Ray Diffraction, Peter A. Beckmann, Carylon Buser, Kathleen Gullifer, Frank B. Mallory, Clelia W. Mallory, Gene M. Rossi, Arnold L. Rheingold

Chemistry Faculty Research and Scholarship

We have synthesized 3-t-butylchrysene and measured the Larmor frequency omega/2pi (= 8.50, 22.5, and 53.0 MHz) and temperature T (110-310 K) dependence of the proton spin-lattice relaxation rate R in the polycrystalline solid [low-frequency solid state nuclear magnetic resonance (NMR) relaxometry]. We have also determined the molecular and crystal structure in a single crystal of 3-t-butylchrysene using x-ray diffraction, which indicates the presence of a unique t-butyl group environment. The spin-1/2 protons relax as a result of the spin-spin dipolar interactions being modulated by the superimposed reorientation of the t-butyl groups and their constituent methyl groups. The reorientation is successfully …


Open Problems From Cccg 2002, Erik D. Demaine, Joseph O'Rourke Jun 2003

Open Problems From Cccg 2002, Erik D. Demaine, Joseph O'Rourke

Computer Science: Faculty Publications

No abstract provided.


Radio Polarization Of The Young High-Magnetic-Field Pulsar Psr J1119-6127, Fronefield Crawford, Nathan C. Keim Jun 2003

Radio Polarization Of The Young High-Magnetic-Field Pulsar Psr J1119-6127, Fronefield Crawford, Nathan C. Keim

Physics

We have investigated the radio polarization properties of PSR J1119-6127, a recently discovered young radio pulsar with a large magnetic field. Using pulsar-gated radio imaging data taken at a center frequency of 2496 MHz with the Australia Telescope Compact Array, we have determined a rotation measure for the pulsar of +842 +/- 23 rad m^-2. These data, combined with archival polarimetry data taken at a center frequency of 1366 MHz with the Parkes telescope, were used to determine the polarization characteristics of PSR J1119-6127 at both frequencies. The pulsar has a fractional linear polarization of ~75% and ~55% at 1366 …


Maximization By Parts In Likelihood Inference, Peter Xuekun Song, Yanqin Fan, Jack Kalbfleisch Jun 2003

Maximization By Parts In Likelihood Inference, Peter Xuekun Song, Yanqin Fan, Jack Kalbfleisch

The University of Michigan Department of Biostatistics Working Paper Series

This paper presents and examines a new algorithm for solving a score equation for the maximum likelyhood estimate in certain problems of practical interest. The method circumvents the need to compute second order derivaties of the full likelihood function. It exploits the structure of certain models that yield a natural decomposition of a very complicated likelihood function. In this decomposition, the first part is a log likelihood from a simply analyzed model and the second part is used to update estimates from the first. Convergence properties of this fixed point algorithm are examined and asymptotics are derived for estimators obtained …


Inelastic Neutron Scattering Signal From Deconfined Spinons In A Fractionalized Antiferromagnet, Courtney Lannert, Matthew P.A. Fisher Jun 2003

Inelastic Neutron Scattering Signal From Deconfined Spinons In A Fractionalized Antiferromagnet, Courtney Lannert, Matthew P.A. Fisher

Physics: Faculty Publications

We calculate the contribution of deconfined spinons to inelastic neutron scattering (INS) in the fractionalized antiferromagnet (AF*), introduced elsewhere. We find that the presence of free spin-1/2 charge-less excitations leads to a continuum INS signal above the Néel gap. This signal is found above and in addition to the usual spin-1 magnon signal, which to lowest order is the same as in the more conventional confined antiferromagnet. We calculate the relative weights of these two signals and find that the spinons contribute to the longitudinal response, where the magnon signal is absent to lowest order. Possible higher-order effects of interactions …


Review Of Irwin M. Brodo, Sylvia Duran Sharnoff, Stephen Sharnoff: Lichens Of North America, Lynn Margulis Jun 2003

Review Of Irwin M. Brodo, Sylvia Duran Sharnoff, Stephen Sharnoff: Lichens Of North America, Lynn Margulis

Lynn Margulis (1938 - 2011)

No abstract provided.


Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Annual Progress Report (May 2002 – May 2003), Ajit K. Roy, Brendan O'Toole Jun 2003

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Annual Progress Report (May 2002 – May 2003), Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

As indicated in the original proposal, the primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate target materials for applications in spallationneutron- target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including Alloy HT-9, Alloy EP 823 and Type 422 stainless steel. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these materials are being evaluated in aqueous environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. …


Use Of Positron Annihilation Spectroscopy For Stress-Strain Measurements: Annual Progress Report (May 2002 – May 2003), Ajit K. Roy Jun 2003

Use Of Positron Annihilation Spectroscopy For Stress-Strain Measurements: Annual Progress Report (May 2002 – May 2003), Ajit K. Roy

Transmutation Sciences Materials (TRP)

The purpose of this collaborative research project involving the University of Nevada Las Vegas (UNLV) and Idaho State University (ISU) to evaluate the feasibility of determining residual stresses of welded, bent (three-point-bend), and cold-worked engineering materials using a new non-destructive technique based on positron annihilation spectroscopy. The proposed technique is the use γ-rays from a small MeV electron Linear accelerator (LINAC) to generate positrons inside the sample via pair production. This method can be used for materials characterization and investigation of defects in thick samples, which could not be accomplished by conventional positron technique or other non-destructive methods. The data …


Minimal Graphs In R3 Over Convex Domains, Michael Dorff Jun 2003

Minimal Graphs In R3 Over Convex Domains, Michael Dorff

Faculty Publications

Krust established that all conjugate and associate surfaces of a minimal graph over a convex domain are also graphs. Using a convolution theorem from the theory of harmonic univalent mappings, we generalize Krust's theorem to include the family of convolution surfaces which are generated by taking the Hadamard product or convolution of mappings. Since this convolution involves convex univalent analytic mappings, this family of convolution surfaces is much larger than just the family of associated surfaces. Also, this generalization guarantees that all the resulting surfaces are over close-toconvex domains. In particular, all the associate surfaces and certain Goursat transformation surfaces …


The Topology Of Hyperbolic Attractors On Compact Surfaces, Todd L. Fisher Jun 2003

The Topology Of Hyperbolic Attractors On Compact Surfaces, Todd L. Fisher

Faculty Publications

Suppose M is a compact surface and M is a nontrivial mixing hyperbolic attractor for some f 2 Diff(M). We show that if is a hyperbolic set for some g 2 Diff(M), then is a nontrivial mixing hyperbolic attractor or repeller for g.


History, Geology And Water In The Lower Platte River Valley In Eastern Nebraska, Dave Gosselin, Marv Carlson, Matt Joeckel Jun 2003

History, Geology And Water In The Lower Platte River Valley In Eastern Nebraska, Dave Gosselin, Marv Carlson, Matt Joeckel

Conservation and Survey Division

No abstract provided.


Application Of A Photopolymer Material In Speckle Pattern Shearing Interferometry, Emilia Mihaylova, Izabela Naydenova, Suzanne Martin, Vincent Toal Jun 2003

Application Of A Photopolymer Material In Speckle Pattern Shearing Interferometry, Emilia Mihaylova, Izabela Naydenova, Suzanne Martin, Vincent Toal

Conference Papers

A new application of a photopolymer diffractive optical element in electronic speckle pattern shearing interferometer (ESPSI) is presented. In the first stage a holographic grating is recorded using an acrylamide based photopolymer material. Since the polymerisation process occurs during recording, the holograms are produced without any development or processing. In the second stage the holographic grating is used to produce the two sheared images in an ESPSI configuration. A ground glass screen following the grating serves the purpose of eliminating unwanted diffraction orders. The distance between the grating and the ground glass can be used to control the amount of …


Assessment Of Ecological Effects Of The Implementation Of Continuous Casting Of Steel, Marian Mazur, Marek Bogacki, Robert Oleniacz, Agnieszka Łopata Jun 2003

Assessment Of Ecological Effects Of The Implementation Of Continuous Casting Of Steel, Marian Mazur, Marek Bogacki, Robert Oleniacz, Agnieszka Łopata

Robert Oleniacz

The article presents a complex analysis of the impact of the technology of continuous casting of steel (CCS) on the rate of the air pollutant emissions from one of the Polish steel and iron plants. The emission sources occurring in the production process have been identified and their rate has been determined. The implementation of CCS has brought about significant changes in the production cycle of the steel plant and it also has caused an increase of the production effectiveness of steel products. The calculated environment effects have shown a considerable emission decrease of all pollutants in the scale of …


An Activity Theory Framework For Computer Interface Design, E. Gould, I. Verenikina Jun 2003

An Activity Theory Framework For Computer Interface Design, E. Gould, I. Verenikina

Faculty of Informatics - Papers (Archive)

Computer interface design has the primary purpose of assisting information technology users in their professional activities. In order to accomplish this, users need to be able to work 'through the interface' to complete the tasks which achieve the goals associated with an activity. Although this is the conceptual province of psychology, very little use has been made of psychology in practical interface design. The attempts that have been made appear to have suffered from a lack of connection to real life problems which has been attributed to their foundations in the information processing structure of cognitive psychology. We elaborate an …


Nanoscale Polarization Manipulation And Conductance Switching In Ultrathin Films Of A Ferroelectric Copolymer, Hongwei Qu, Wei Yao, T. Garcia, Jiandi Zhang, A.V. Sorokin, Stephen Ducharme, Peter A. Dowben, V.M. Fridkin Jun 2003

Nanoscale Polarization Manipulation And Conductance Switching In Ultrathin Films Of A Ferroelectric Copolymer, Hongwei Qu, Wei Yao, T. Garcia, Jiandi Zhang, A.V. Sorokin, Stephen Ducharme, Peter A. Dowben, V.M. Fridkin

Peter Dowben Publications

We report the direct observation of induced molecular reorientation on a ferroelectric copolymer with a scanning tunneling microscope (STM). Ultrathin copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%) revealed a quasihexagonal close-packing structure with long-range polymer chain ordering. By flipping the polarity of the STM tip bias voltage, a reversal of local polarization was observed through an apparent lattice shift and was accompanied by an asymmetric ‘‘diode-like’’ character in tunneling current I(V). These results clearly demonstrated conductance switching behavior on nanoscale with local polarization reversal. © 2003 American Institute of Physics.


Phase Ii: Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Randy Clarksean, Darrell Pepper Jun 2003

Phase Ii: Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Randy Clarksean, Darrell Pepper

Fuels Campaign (TRP)

This research report develops a model to analyze the transport of americium from the melt to the vapor phase above the crucible. The model considers mass transport in the melt, vaporization at the surface, and transport through the vapor phase. The greatest problem with the model is the uncertainty of the thermodynamic properties of the proposed ternary alloy. The details of the model and the specific quantities needed for the physical properties will be discussed.


Progressing Towards Governance For Sustainability At Parkfield School: Making Connections Through Dialogical Design, Sandra Wooltorton, Alan Kidd Jun 2003

Progressing Towards Governance For Sustainability At Parkfield School: Making Connections Through Dialogical Design, Sandra Wooltorton, Alan Kidd

Sandra Wooltorton

No abstract provided.


Source Of Tiny Wiggles In Chron C5: A Comparison Of Sedimentary Relative Intensity And Marine Magnetic Anomalies, Julie A. Bowles, Lisa Tauxe, Jeffrey S. Gee, David Mcmillan, Steve Cande Jun 2003

Source Of Tiny Wiggles In Chron C5: A Comparison Of Sedimentary Relative Intensity And Marine Magnetic Anomalies, Julie A. Bowles, Lisa Tauxe, Jeffrey S. Gee, David Mcmillan, Steve Cande

Geosciences Faculty Articles

In addition to the well-established pattern of polarity reversals, short-wavelength fluctuations are often present in both sea-surface data ("tiny wiggles") and near-bottom anomaly data. While a high degree of correlation between different geographical regions suggests a geomagnetic origin for some of these wiggles, anomaly data alone cannot uniquely determine whether they represent short reversals or paleointensity variations. Independent evidence from another geomagnetic recording medium such as deep-sea sediments is required to determine the true nature of the tiny wiggles. We present such independent evidence in the form of sedimentary relative paleointensity from Chron C5. We make the first comparison between …


Phytoplankton Response To Intrusions Of Slope Water On The West Florida Shelf: Models And Observations, John J. Walsh, Robert H. Weisberg, Dwight A. Dieterle, Ruoying He, Brian P. Darrow, Jason K. Jolliff, Kristen M. Lester, Gabriel A. Vargo, Gary J. Kirkpatrick, Kent A. Fanning, Tracey Sutton, Ann E. Jochens, Douglas C. Biggs, Bisman Nababan, Chuanmin Hu, Frank E. Muller-Karger Jun 2003

Phytoplankton Response To Intrusions Of Slope Water On The West Florida Shelf: Models And Observations, John J. Walsh, Robert H. Weisberg, Dwight A. Dieterle, Ruoying He, Brian P. Darrow, Jason K. Jolliff, Kristen M. Lester, Gabriel A. Vargo, Gary J. Kirkpatrick, Kent A. Fanning, Tracey Sutton, Ann E. Jochens, Douglas C. Biggs, Bisman Nababan, Chuanmin Hu, Frank E. Muller-Karger

Marine & Environmental Sciences Faculty Articles

Previous hypotheses had suggested that upwelled intrusions of nutrient-rich Gulf of Mexico slope water onto the West Florida Shelf (WFS) led to formation of red tides of Karenia brevis. However, coupled biophysical models of (1) wind- and buoyancy-driven circulation, (2) three phytoplankton groups (diatoms, K. brevis, and microflagellates), (3) these slope water supplies of nitrate and silicate, and (4) selective grazing stress by copepods and protozoans found that diatoms won in one 1998 case of no light limitation by colored dissolved organic matter (CDOM). The diatoms lost to K. brevis during another CDOM case of the models. In …


A Generative Programming Framework For Adaptive Middleware, Venkita Subramonian, Christopher Gill Jun 2003

A Generative Programming Framework For Adaptive Middleware, Venkita Subramonian, Christopher Gill

All Computer Science and Engineering Research

Historically, many distributed real-time and embedded (DRE) systems were developed manually from scratch, leading to stove-piped solutions that while correct in both functional and QoS properties were very expensive to develop and difficult to maintain and extend. First-generation middleware technologies such as CORBA 2.x [1], XML [2], and SOAP [3], served to shield application developers from low-level platform details, thus raising the level of abstraction at which distributed systems are developed and supporting reuse of infrastructure to amortize development costs over the lifetime of a system. However, interdependencies between services and object interfaces resulting from these programming models significantly limited …


Design Considerations For Efficient And Effective Microarray Studies, M. Kathleen Kerr Jun 2003

Design Considerations For Efficient And Effective Microarray Studies, M. Kathleen Kerr

UW Biostatistics Working Paper Series

This paper describes the theoretical and practical issues in experimental design for gene expression microarrays. Specifically, this paper (1) discusses the basic principles of design (randomization, replication, and blocking) as they pertain to microarrays, and (2) provides some general guidelines for statisticians designing microarray studies.


Slides: A Water Manager's Perspective: A View From The Field, Jeffrey Kightlinger Jun 2003

Slides: A Water Manager's Perspective: A View From The Field, Jeffrey Kightlinger

Water, Climate and Uncertainty: Implications for Western Water Law, Policy, and Management (Summer Conference, June 11-13)

Presenter: Jeffrey Kightlinger, General Counsel, Metropolitan Water District of Southern California (MWD)

21 slides


Slides: Final Panel Questions, Doug Kenney Jun 2003

Slides: Final Panel Questions, Doug Kenney

Water, Climate and Uncertainty: Implications for Western Water Law, Policy, and Management (Summer Conference, June 11-13)

Presenter and Moderator: Doug Kenney, Natural Resources Law Center

1 slide


Conference Summary: Water, Climate And Uncertainty: Implications For Western Water Law, Policy, And Management, Steve Bailey Jun 2003

Conference Summary: Water, Climate And Uncertainty: Implications For Western Water Law, Policy, And Management, Steve Bailey

Water, Climate and Uncertainty: Implications for Western Water Law, Policy, and Management (Summer Conference, June 11-13)

7 pages.

"Steve Bailey, National Center for Atmospheric Research"


Either/Or? Will Climate Change Force A Choice Between Salmon And Electricity In The Northwest?, John M. Volkman Jun 2003

Either/Or? Will Climate Change Force A Choice Between Salmon And Electricity In The Northwest?, John M. Volkman

Water, Climate and Uncertainty: Implications for Western Water Law, Policy, and Management (Summer Conference, June 11-13)

12 pages and 16 slides

Includes bibliographical references

"John M. Volkman, Partner, Stoel Rives LLP, Portland, Oregon"