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2003

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Full-Text Articles in Physical Sciences and Mathematics

Влияние На Окружающую Среду Технологии Непрерывного Литья, Marian Mazur, Marek Bogacki, Robert Oleniacz, Agnieszka Łopata Dec 2003

Влияние На Окружающую Среду Технологии Непрерывного Литья, Marian Mazur, Marek Bogacki, Robert Oleniacz, Agnieszka Łopata

Robert Oleniacz

This 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 ...


Problems With The Dartmouth Wireless Snmp Data Collection, Tristan Henderson, David Kotz Dec 2003

Problems With The Dartmouth Wireless Snmp Data Collection, Tristan Henderson, David Kotz

Open Dartmouth: Peer-reviewed articles by Dartmouth faculty

The original Dartmouth wireless network study used SNMP to query the college's Cisco 802.11b access points. The perl scripts that performed the SNMP queries suffered from some problems, in that they queried inappropriate SNMP values, or misunderstood the meaning of other values. This data was also used in a subsequent analysis. The same scripts were used to collect data for a subsequent study of another wireless network. This document outlines these problems and indicates which of the data collected by the original scripts may be invalid.


Pion-Kaon Correlations In Central Au+Au Collisions At √SNn=130 Gev, Star Collaboration, T.D. Gutierrez Dec 2003

Pion-Kaon Correlations In Central Au+Au Collisions At √SNn=130 Gev, Star Collaboration, T.D. Gutierrez

Physics

Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at √sNN=130  GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.


Traveling Waves In Rotating Rayleigh-Bénard Convection: Analysis Of Modes And Mean Flow, Janet Scheel, M. Paul, P. Fishcer Dec 2003

Traveling Waves In Rotating Rayleigh-Bénard Convection: Analysis Of Modes And Mean Flow, Janet Scheel, M. Paul, P. Fishcer

Janet D. Scheel

Numerical simulations of the Boussinesq equations with rotation for realistic no-slip boundary conditions and a finite annular domain are presented. These simulations reproduce traveling waves observed experimentally. Traveling waves are studied near threshhold by using the complex Ginzburg-Landau equation (CGLE): a mode analysis enables the CGLE coefficients to be determined. The CGLE coefficients are compared with previous experimental and theoretical results. Mean flows are also computed and found to be more significant as the Prandtl number decreases (from σ=6.4 to σ=1). In addition, the mean flow around the outer radius of the annulus appears to be correlated ...


Anomaly In Conformal Quantum Mechanics: From Molecular Physics To Black Holes, Horacio E. Camblong Dec 2003

Anomaly In Conformal Quantum Mechanics: From Molecular Physics To Black Holes, Horacio E. Camblong

Physics and Astronomy

A number of physical systems exhibit a particular form of asymptotic conformal invariance: within a particular domain of distances, they are characterized by a long-range conformal interaction (inverse square potential), the apparent absence of dimensional scales, and an SO(2,1) symmetry algebra. Examples from molecular physics to black holes are provided and discussed within a unified treatment. When such systems are physically realized in the appropriate strong-coupling regime, the occurrence of quantum symmetry breaking is possible. This anomaly is revealed by the failure of the symmetry generators to close the algebra in a manner shown to be independent of ...


Final Report: An Assessment To Determine The Most Suitable Location And Design For The Development Of A City-Run, Boat Sewage Pumpout Facility To Service Commercial And Recreational Vessels That Utilize The Waters Within The Jurisdiction Of The City Of Boston, Urban Harbors Institute, University Of Massachusetts Boston Dec 2003

Final Report: An Assessment To Determine The Most Suitable Location And Design For The Development Of A City-Run, Boat Sewage Pumpout Facility To Service Commercial And Recreational Vessels That Utilize The Waters Within The Jurisdiction Of The City Of Boston, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

This report presents the findings of a site and equipment feasibility study, as well as, a permit overview for the installation of a vessel sewage pumpout system for servicing commercial and recreational vessels in the City of Boston. As part of the analysis, we reviewed a number of sites located within the City of Boston’s jurisdiction in Boston Harbor. We contacted facilities that have made recent investments in commercial grade pumpouts to learn more about the available technology. In analyzing the permit process, we reviewed local zoning requirements and had conversations with relevant City and state officials.

The project ...


Collaborative Research: Origins Of Cods On Georges Bank: Contributions Of Early Developmental Stages For The Scotian Shelf, David W. Townsend, Irv Kornfield, Linda Kling Dec 2003

Collaborative Research: Origins Of Cods On Georges Bank: Contributions Of Early Developmental Stages For The Scotian Shelf, David W. Townsend, Irv Kornfield, Linda Kling

University of Maine Office of Research Administration: Grant Reports

Recent work in the Georges Bank-Gulf of Maine area has documented significant, and apparently episodic, fluxes of Scotian Shelf Water (SSW) from the Nova Scotian continental shelf to Georges Bank. SSW is a relatively cold and fresh water mass with a significant component from the St. Lawrence River, and is commonly identifiable with temperature-salinity analyses of hydrographic data and in satellite images of sea surface temperature. One such flux episode was observed last March (1997) in satellite imagery and from shipboard hydrographic sampling on Georges Bank. Qualitative at-sea analyses of ichthyoplankton sampled on the March cruise revealed a remarkably tight ...


Macrocyclic Antibiotics As Separation Agents, Daniel W. Armstrong Dec 2003

Macrocyclic Antibiotics As Separation Agents, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Macrocyclic antibiotics having ring structures with at least 10 members act as separation agents in crystallization, precipitation, filtration, electrophoresis, and chromatography. The macrocyclic antibiotics include ansamacrolides, macrolides, macrocyclic peptides, polyenes and derivatives thereof. The process has been found to be especially advantageous for separation of optical isomers by electrophoresis and chromatography.


A Review Of Color Vision In White-Tailed Deer, Kurt C. Vercauteren, Michael J. Pipas Dec 2003

A Review Of Color Vision In White-Tailed Deer, Kurt C. Vercauteren, Michael J. Pipas

USDA National Wildlife Research Center - Staff Publications

A better understanding of the color vision abilities of white-tailed deer (Odocoileus virginianus) helps to determine how these animals interpret their environment. We review and summarize the literature related to the color vision abilities of white-tailed deer. Physiological measurements using advanced techniques such as molecular genetics, electroretinography, and electron microscopy have demonstrated conclusively that whitetailed deer possess the anatomical requisites for color vision. Operant conditioning techniques employed in pen studies using trained cervids confirm that deer see color. The eyes of white-tailed deer are characterized by 3 classes of photopigments: a short-wavelengthsensitive cone mechanism, a middle-wavelength-sensitive cone mechanism, and a ...


Coyote (Canis Latrans), Marc Bekoff, Eric M. Gese Dec 2003

Coyote (Canis Latrans), Marc Bekoff, Eric M. Gese

USDA National Wildlife Research Center - Staff Publications

Coyotes


Live Capture Of Denning Mammals Using An Improved Box-Trap Enclosure: Kit Foxes As A Test Case, Adam J. Kozlowski, Tim J. Bennett, Eric M. Gese, Wendy M. Arjo Dec 2003

Live Capture Of Denning Mammals Using An Improved Box-Trap Enclosure: Kit Foxes As A Test Case, Adam J. Kozlowski, Tim J. Bennett, Eric M. Gese, Wendy M. Arjo

USDA National Wildlife Research Center - Staff Publications

The ability to capture and recapture animals efficiently is ,In integral part of many wildlife studies. For many species of small terrestrial carnivores, the baited box trap has been a staple of live-capture trapping efforts. Combined with an enclosure, the box trap is especially effective on species with a den or refuge that can be encircled. However, increased trapping success of these enclosure designs often is offset by increased cost, labor, and awkwardness of transporting and establishing the enclosure trap. We describe a new enclosure design, the tunnel trap, which improves on the mobility and effectiveness of previous enclosure designs ...


On Analytical Methods And Inferences For 2 X 2 Contingency Table Data Using Wildlife Examples, Richard M. Engeman, George D. Swanson Dec 2003

On Analytical Methods And Inferences For 2 X 2 Contingency Table Data Using Wildlife Examples, Richard M. Engeman, George D. Swanson

USDA National Wildlife Research Center - Staff Publications

The 2 X 2 contingency table is common analytical method for wildlife studies, but inappropriate analyses and inferences are not uncommon. Issues of concern are presented for selecting the appropriate test for analyzing these data sets. These include the choice of test relative to experimental or sampling design and breadth of intended inferences, the careful statement of hypotheses, and analyses with small sample sizes. Examples from the wildlife literature are used to reinforce the statistical concepts.


Diffusion And Drift In Terahertz Emission At Gaas Surfaces, James Heyman, N Coates, A Reinhardt, G Strasser Dec 2003

Diffusion And Drift In Terahertz Emission At Gaas Surfaces, James Heyman, N Coates, A Reinhardt, G Strasser

James Heyman

No abstract provided.


Lewis And Clark And The Geology Of Nebraska And Parts Of Adjacent States, Robert F. Diffendal, Anne P. Diffendal Dec 2003

Lewis And Clark And The Geology Of Nebraska And Parts Of Adjacent States, Robert F. Diffendal, Anne P. Diffendal

Papers in Natural Resources

Meriwether Lewis and William Clark undertook their journey with the Corps of Discovery in 1804–1806 in order to explore the area that the United States had purchased from France in 1803. Then known as Louisiana, this region included almost everything west of the Mississippi to the continental divide (illustrated below). In order to find the best route across the continent, President Thomas Jefferson charged Lewis to follow the Missouri River to its headwaters and then locate rivers flowing down the west side of the Rocky Mountains to the Columbia River and into the Pacific Ocean. Jefferson's written instructions ...


Robust Likelihood-Based Analysis Of Multivariate Data With Missing Values, Rod Little, An Hyonggin Dec 2003

Robust Likelihood-Based Analysis Of Multivariate Data With Missing Values, Rod Little, An Hyonggin

The University of Michigan Department of Biostatistics Working Paper Series

The model-based approach to inference from multivariate data with missing values is reviewed. Regression prediction is most useful when the covariates are predictive of the missing values and the probability of being missing, and in these circumstances predictions are particularly sensitive to model misspecification. The use of penalized splines of the propensity score is proposed to yield robust model-based inference under the missing at random (MAR) assumption, assuming monotone missing data. Simulation comparisons with other methods suggest that the method works well in a wide range of populations, with little loss of efficiency relative to parametric models when the latter ...


Projectile-Shape Dependence Of Impact Craters In Loose Granular Media, K. A. Newhall Dec 2003

Projectile-Shape Dependence Of Impact Craters In Loose Granular Media, K. A. Newhall

Department of Physics Papers

We report on the penetration of cylindrical projectiles dropped from rest into a dry, noncohesive granular medium. The cylinder length, diameter, density, and tip shape are all explicitly varied. For deep penetrations, as compared to the cylinder diameter, the data collapse onto a single scaling law that varies as the 1/3 power of the total drop distance, the 1/2 power of cylinder length, and the 1/6 power of cylinder diameter. For shallow penetrations, the projectile shape plays a crucial role with sharper objects penetrating deeper.


Three-Pion Hanbury Brown–Twiss Correlations In Relativistic Heavy-Ion Collisions From The Star Experiment, Star Collaboration, T.D. Gutierrez Dec 2003

Three-Pion Hanbury Brown–Twiss Correlations In Relativistic Heavy-Ion Collisions From The Star Experiment, Star Collaboration, T.D. Gutierrez

Physics

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at √sNN=130   GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.


Resonant Emergence Of Global And Local Spatiotemporal Order In A Nonlinear Field Model, Marcelo Gleiser, Rafael C. Howell Dec 2003

Resonant Emergence Of Global And Local Spatiotemporal Order In A Nonlinear Field Model, Marcelo Gleiser, Rafael C. Howell

Open Dartmouth: Peer-reviewed articles by Dartmouth faculty

We investigate the nonequilibrium evolution of a scalar field in (2+1) dimensions. The field is set in a double-well potential in contact (open) or not (closed) with a heat bath. For closed systems, we observe the synchronized emergence of coherent spatiotemporal configurations, identified with oscillons. This initial global ordering degenerates into localized order until all oscillons disappear. We show that the synchronization is driven by resonant parametric oscillations of the field’s zero mode and that local ordering is only possible outside equipartition. None of these orderings occur for open systems.


Fundamental And Magnetic-Hardening Studies Of Rare-Earth And Nanocomposite Magnets, David J. Sellmyer, George C. Hadjipanayis Dec 2003

Fundamental And Magnetic-Hardening Studies Of Rare-Earth And Nanocomposite Magnets, David J. Sellmyer, George C. Hadjipanayis

David Sellmyer Publications

In this project we study new nanocrystalline and nanocomposite structures that have high potential for permanent-magnet development. These materials, which can be synthesized to have either very high or intermediate coercivities, have many applications in electric power, transportation, and information-storage industries. There is great interest in further development of understanding and application of these materials. Following are brief discussions of recent research highlights for the present grant.


Uncertainty And The Value Of Diagnostic Information With Application To Axillary Lymph Node Dissection In Breast Cancer, Giovanni Parmigiani Dec 2003

Uncertainty And The Value Of Diagnostic Information With Application To Axillary Lymph Node Dissection In Breast Cancer, Giovanni Parmigiani

Johns Hopkins University, Dept. of Biostatistics Working Papers

In clinical decision making, it is common to ask whether, and how much, a diagnostic procedure is contributing to subsequent treatment decisions. Statistically, quantification of the value of the information provided by a diagnostic procedure can be carried out using decision trees with multiple decision points, representing both the diagnostic test and the subsequent treatments that may depend on the test's results. This article investigates probabilistic sensitivity analysis approaches for exploring and communicating parameter uncertainty in such decision trees. Complexities arise because uncertainty about a model's inputs determines uncertainty about optimal decisions at all decision nodes of a ...


Marginalized Transition Models For Longitudinal Binary Data With Ignorable And Nonignorable Dropout, Brenda F. Kurland, Patrick J. Heagerty Dec 2003

Marginalized Transition Models For Longitudinal Binary Data With Ignorable And Nonignorable Dropout, Brenda F. Kurland, Patrick J. Heagerty

UW Biostatistics Working Paper Series

We extend the marginalized transition model of Heagerty (2002) to accommodate nonignorable monotone dropout. Using a selection model, weakly identified dropout parameters are held constant and their effects evaluated through sensitivity analysis. For data missing at random (MAR), efficiency of inverse probability of censoring weighted generalized estimating equations (IPCW-GEE) is as low as 40% compared to a likelihood-based marginalized transition model (MTM) with comparable modeling burden. MTM and IPCW-GEE regression parameters both display misspecification bias for MAR and nonignorable missing data, and both reduce bias noticeably by improving model fit


Self-Aligned Mechanical Attachment Of Carbon Nanotubes To Silicon Dioxide Structures By Selective Silicon Dioxide Chemical-Vapor Deposition, Jed D. Whittaker, Ghaleb A. Husseini, Matthew A. Linford, Robert C. Davis, Markus Brink Dec 2003

Self-Aligned Mechanical Attachment Of Carbon Nanotubes To Silicon Dioxide Structures By Selective Silicon Dioxide Chemical-Vapor Deposition, Jed D. Whittaker, Ghaleb A. Husseini, Matthew A. Linford, Robert C. Davis, Markus Brink

Faculty Publications

A self-aligned thin-film deposition technique was developed to mechanically attach carbon nanotubes to surfaces for the fabrication of structurally robust nanotube-based nanomechanical devices. Single-walled carbon nanotubes were grown by thermal chemical-vapor deposition (CVD) across 150-nm-wide SiO2 trenches. The nanotubes were mechanically attached to the trench tops by selective silicon tetraacetate-based SiO2 CVD. No film was deposited on the nanotubes where they were suspended across the trenches.


Ion Cyclotron Waves In The High Altitude Cusp: Cluster Observations At Varying Spacecraft Separations, K. Nykyri, P. J. Cargill, E. A. Lucek, T. S. Horbury, A. Balogh, B. Lavraud, I. Dandouras, H. Reme Dec 2003

Ion Cyclotron Waves In The High Altitude Cusp: Cluster Observations At Varying Spacecraft Separations, K. Nykyri, P. J. Cargill, E. A. Lucek, T. S. Horbury, A. Balogh, B. Lavraud, I. Dandouras, H. Reme

Publications

We have analysed high-resolution Cluster magnetic field data during three high-altitude cusp crossings in 2001 and 2002. The Cluster separations for these crossings varied between 100 and 600 km and therefore provided an unique opportunity to study wave properties at different length scales. In the cusp Cluster sees frequent intervals of magnetic field fluctuations with clear peaks in power close to the local ion cyclotron frequency, and both left- and right-handed polarisations. At large separations the power seen at different spacecraft can differ by orders of magnitude. For smaller separations, the power seen at the four spacecraft agrees better but ...


Search For High-Energy Gamma Rays From An X-Ray-Selected Blazar Sample, P. T. Reynolds, Et. Al. Dec 2003

Search For High-Energy Gamma Rays From An X-Ray-Selected Blazar Sample, P. T. Reynolds, Et. Al.

Physical Sciences Publications

Our understanding of blazars has been greatly increased in recent years by extensive multiwavelength observations, particularly in the radio, X-ray, and gamma-ray regions. Over the past decade the Whipple 10 m telescope has contributed to this with the detection of five BL Lacertae objects at very high gamma-ray energies. The combination of multiwavelength data has shown that blazars follow a well-defined sequence in terms of their broadband spectral properties. Together with providing constraints on emission models, this information has yielded a means by which potential sources of TeV emission may be identified and predictions made as to their possible gamma-ray ...


Marginal Modeling Of Multilevel Binary Data With Time-Varying Covariates, Diana Miglioretti, Patrick Heagerty Dec 2003

Marginal Modeling Of Multilevel Binary Data With Time-Varying Covariates, Diana Miglioretti, Patrick Heagerty

UW Biostatistics Working Paper Series

We propose and compare two approaches for regression analysis of multilevel binary data when clusters are not necessarily nested: a GEE method that relies on a working independence assumption coupled with a three-step method for obtaining empirical standard errors; and a likelihood-based method implemented using Bayesian computational techniques. Implications of time-varying endogenous covariates are addressed. The methods are illustrated using data from the Breast Cancer Surveillance Consortium to estimate mammography accuracy from a repeatedly screened population.


Survival Model Predictive Accuracy And Roc Curves, Patrick Heagerty, Yingye Zheng Dec 2003

Survival Model Predictive Accuracy And Roc Curves, Patrick Heagerty, Yingye Zheng

UW Biostatistics Working Paper Series

The predictive accuracy of a survival model can be summarized using extensions of the proportion of variation explained by the model, or R^2, commonly used for continuous response models, or using extensions of sensitivity and specificity which are commonly used for binary response models.

In this manuscript we propose new time-dependent accuracy summaries based on time-specific versions of sensitivity and specificity calculated over risk sets. We connect the accuracy summaries to a previously proposed global concordance measure which is a variant of Kendall's tau. In addition, we show how standard Cox regression output can be used to obtain ...


Semiparametric Estimation Of Time-Dependent: Roc Curves For Longitudinal Marker Data, Yingye Zheng, Patrick Heagerty Dec 2003

Semiparametric Estimation Of Time-Dependent: Roc Curves For Longitudinal Marker Data, Yingye Zheng, Patrick Heagerty

UW Biostatistics Working Paper Series

One approach to evaluating the strength of association between a longitudinal marker process and a key clinical event time is through predictive regression methods such as a time-dependent covariate hazard model. For example, a time-varying covariate Cox model specifies the instantaneous risk of the event as a function of the time-varying marker and additional covariates. In this manuscript we explore a second complementary approach which characterizes the distribution of the marker as a function of both the measurement time and the ultimate event time. Our goal is to flexibly extend the standard diagnostic accuracy concepts of sensitivity and specificity to ...


Partly Conditional Survival Models For Longitudinal Data, Yingye Zheng, Patrick Heagerty Dec 2003

Partly Conditional Survival Models For Longitudinal Data, Yingye Zheng, Patrick Heagerty

UW Biostatistics Working Paper Series

It is common in longitudinal studies to collect information on the time until a key clinical event, such as death, and to measure markers of patient health at multiple follow-up times. One approach to the joint analysis of survival and repeated measures data adopts a time-varying covariate regression model for the event time hazard. Using this standard approach the instantaneous risk of death at time t is specified as a possibly semi-parametric function of covariate information that has accrued through time t. In this manuscript we decouple the time scale for modeling the hazard from the time scale for accrual ...


Swine Waste Demonstration And Training Project, C. V. Maxwell, K. Vandevender, K. P. Coffey, P. A. Moore, I. Chaubey, D. R. Smith Dec 2003

Swine Waste Demonstration And Training Project, C. V. Maxwell, K. Vandevender, K. P. Coffey, P. A. Moore, I. Chaubey, D. R. Smith

Technical Reports

No abstract provided.


Breaking Of Thunderstorm-Generated Gravity Waves As A Source Of Short-Period Ducted Waves At Mesopause Altitudes, Jonathan B. Snively, Victor P. Pasko Dec 2003

Breaking Of Thunderstorm-Generated Gravity Waves As A Source Of Short-Period Ducted Waves At Mesopause Altitudes, Jonathan B. Snively, Victor P. Pasko

Publications

Numerical simulation results indicate that the breaking of atmospheric gravity waves generated by tropospheric convection can excite short-period secondary waves, which are trapped in the lower thermospheric duct and which closely resemble quasi-monochromatic structures commonly observed in airglow imaging experiments.