Physical Sciences and Mathematics Commons^™

Search For Neutral Baryon Resonances Below Pion Threshold, X Jiang, R Gilman, R Ransome, P Markowitz, T H. Chang, C C. Chang, Gerald Alvin Peterson

Gerald Alvin Peterson

The reaction p(e,e′π+)X0 was studied with two high-resolution magnetic spectrometers to search for narrow baryon resonances. A missing mass resolution of 2.0 MeV was achieved. A search for structures in the mass region of 0.97

Seasonal And Diurnal Variation Of Geomagnetic Activity: Revised Dst Versus External Drivers, L V.T Hakkinen, T I. Pulkkinen, R J. Pirjola, H Nevanlinna, E I. Tanskanen, Niescja E. Turner

Physics and Astronomy Faculty Research

Daily and seasonal variability of long time series of magnetometer data from Dst stations is examined. Each station separately shows a local minimum of horizontal magnetic component near 18 local time (LT) and weakest activity near 06 LT. The stations were found to have different baselines such that the average levels of activity differed by about 10 nT. This effect was corrected for by introducing a new “base method” for the elimination of the secular variation. This changed the seasonal variability of the Dst index by about 3 nT. The hemispheric differences between the annual variation (larger activity during local …

Asymptotic Optimality Of Likelihood Based Cross-Validation, Mark J. Van Der Laan, Sandrine Dudoit, Sunduz Keles

U.C. Berkeley Division of Biostatistics Working Paper Series

Likelihood-based cross-validation is a statistical tool for selecting a density estimate based on n i.i.d. observations from the true density among a collection of candidate density estimators. General examples are the selection of a model indexing a maximum likelihood estimator, and the selection of a bandwidth indexing a nonparametric (e.g. kernel) density estimator. In this article, we establish asymptotic optimality of a general class of likelihood based cross-validation procedures (as indexed by the type of sample splitting used, e.g. V-fold cross-validation), in the sense that the cross-validation selector performs asymptotically as well (w.r.t. to the Kullback-Leibler distance to the true …

Asymptotics Of Cross-Validated Risk Estimation In Estimator Selection And Performance Assessment, Sandrine Dudoit, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Risk estimation is an important statistical question for the purposes of selecting a good estimator (i.e., model selection) and assessing its performance (i.e., estimating generalization error). This article introduces a general framework for cross-validation and derives distributional properties of cross-validated risk estimators in the context of estimator selection and performance assessment. Arbitrary classes of estimators are considered, including density estimators and predictors for both continuous and polychotomous outcomes. Results are provided for general full data loss functions (e.g., absolute and squared error, indicator, negative log density). A broad definition of cross-validation is used in order to cover leave-one-out cross-validation, V-fold …

Comparative Standards For Intensive Livestock Operations In Canada, Mexico, And The United States, Jerry Speir, Marie-Ann Bowden, David E. Ervin, Jim Mcelfish, Rosario P. Espejo, Tim Whitehouse, Chantal L. Carpentier

Economics Faculty Publications and Presentations

Livestock farming has been transformed in the past twenty years from a business dominated by relatively small producers to one dominated by large facilities raising thousands of animals. A side effect of this development has been a new set of environmental concerns unique to this industry. While regulation of livestock agriculture has historically been a state/provincial and local matter, governments from the local to the federal level have found themselves grappling with the issues created by these new, concentrated facilities. This Report surveys the current environmental requirements for "intensive livestock operations" (ILOs) in the United States, Mexico and Canada. The …

Predator Odours As Reproductive Inhibitors For Norway Rats, Vera V. Voznessenskaya, Sergey V. Naidenko, Natalia Yu. Feoktistova, Georgy J. Krivomazov, Lowell A. Miller, Larry Clark

United States Department of Agriculture Wildlife Services: Staff Publications

We examined the influence of predator odor on reproductive output of Norway rats (Rattus norvegicus). Naive laboratory rats responded to predator chemical cues with reduced litter sire and skewed sex ratio. We found that exposure to predator urine had its greatest effect on implantation and maintenance of implantation when predator urine was applied to the bedding of rats during the first third of gestation. Based on the physical appearance of corpora lutea and uterine implantation scars, we found that the reduction in litter sire was due to resolution of the embryos during the early part of gestation. Subsequently, …

Chemomechanical Surface Patterning And Functionalization Of Silicon Surfaces Using An Atomic Force Microscope, Brent A. Wascaser, Michael J. Maughan, Travis L. Niederhauser, Matthew R. Linford, Robert C. Davis, Ian A. Mowat

Faculty Publications

Surface modification and patterning at the nanoscale is a frontier in science with significant possible applications in biomedical technology and nanoelectronics. Here we show that an atomic force microscope (AFM) can be employed to simultaneously pattern and functionalize hydrogen-terminated silicon (111) surfaces. The AFM probe was used to break Si-H and Si-Si bonds in the presence of reactive molecules, which covalently bonded to the scribed Si surface. Functionalized patches and patterned lines of molecules were produced. Linewidths down to 30 nm were made by varying the force at the tip

X-Ray Radiation From Nonlinear Thomson Scattering Of An Intense Femtosecond Laser On Relativistic Electrons In A Helium Plasma, K. Ta Phuoc, A. Rousse, M. Pittman, J.P. Rousseau, Victor Malka, S. Fritzler, Donald P. Umstadter, D. Hulin

Donald Umstadter Publications

We have generated x-ray radiation from the nonlinear Thomson scattering of a 30 fs/1.5 J laser beam on plasma electrons. A collimated x-ray radiation with a broad continuous spectrum peaked at 0.15 keV with a significant tail up to 2 keV has been observed. These characteristics are found to depend strongly on the laser strength parameter a₀. This radiative process is dominant for a₀ greater than unity at which point the relativistic scattering of the laser light originates from MeV energy electrons inside the plasma.

Water Current, Volume 35, No. 1, February 2003

Water Current Newsletter

Plans Taking Shape for Summer Tour; Geologists to Meet In Lincoln
Meet the Faculty
New Analytic Equipment Increases Water Sciences Lab Capabilities
Effects of Heavy Sedimentation on Rainwater Basin Wetland Hydrology
Students Get Their Feet Wet at Audubon Spring Creek Prairie
Water News Briefs
Free Water and Natural Resources Lectures Continue at UNL

Modern Spectral Climate Patterns In Rhythmically Deposited Argillites Of The Gowganda Formation (Early Proterozoic), Southern Ontario, Canada, Gary B. Hughes, Robert Giegengack, Haralambos N. Kritikos

Statistics

Rhythmically deposited argillites of the Gowganda Formation (ca. 2.0–2.5 Ga) probably formed in a glacial setting. Drop stones and layered sedimentary couplets in the rock presumably indicate formation in a lacustrine environment with repeating freeze–thaw cycles. It is plausible that temporal variations in the thickness of sedimentary layers are related to interannual climatic variability, e.g. average seasonal temperature could have influenced melting and the amount of sediment source material carried to the lake. A sequence of layer couplet thickness measurements was made from high-resolution digitized photographs taken at an outcrop in southern Ontario, Canada. The frequency spectrum of thickness measurements …

Hard X-Ray Polarimetry With The Ramaty High Energy Solar Spectroscopic Imager (Rhessi), Mark L. Mcconnell, David M. Smith, A G. Emslie, Robert P. Lin, James M. Ryan

Space Science Center

Although designed primarily as a hard X-ray imager and spectrometer, the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) is also capable of measuring the polarization of hard X-rays (20-100 keV) from solar flares. This capability arises from the inclusion of a small unobstructed Be scattering element that is strategically located within the cryostat that houses the array of nine germanium detectors. The Ge detectors are segmented, with both a front and rear active volume. Low energy photons (below about 100 keV) can reach a rear segment of a Ge detector only indirectly, by scattering. Low energy photons from the Sun …

Sontrac: An Imaging Spectrometer For Solar Neutrons, James M. Ryan, L Desorgher, E O. Fluckiger, John R. Macri, Mark L. Mcconnell, R S. Miller

Space Science Center

An instrument capable of unambiguously determining the energy and direction of incident neutrons has important applications in solar physics-as well as environmental monitoring and medical/radiological sciences. The SONTRAC (SOlar Neutron TRACking) instrument is designed to operate in the neutron energy range of 20-250 MeV. The measurement principle is based on non-relativistic double scatter of neutrons off ambient protons (n-p scattering) within a block of densely packed scintillating fibers. Using this double-scatter mode it is possible to uniquely determine neutron energy and direction on an event-by-event basis. A fully operational science model of such an instrument has been built using 300 …

Gray Whales Off Sakhalin Island, Russia: June – September 2001: A Joint U.S. – Russia Scientific Investigation, David W. Weller, Alexander M. Burdin, Amanda L. Bradford, Grigory A. Tsidulko, Yulia V. Ivashchenko, Robert L. Brownell Jr.

United States Department of Commerce: Staff Publications

Numerous species of marine mammals inhabit the Sea of Okhotsk. Two of the most endangered populations of large whales in the world; the Okhotsk Sea bowhead whale (Balaena mysticetus) and the western North Pacific (Okhotsk-Korean) gray whale are known to occur in this sea (Brownell et al., 1997; Clapham et al., 1999). Concerns regarding the status of these whale populations have been intensified by the onset of offshore oil and gas development programs in Okhotsk waters. Anthropogenic activities related to oil and gas exploration off the northeastern Sakhalin Island shelf include geophysical seismic surveying, drilling and production operations, …

Chemical Abundances In Broad Emission Line Regions: The "Nitrogen-Loud'' Quasi-Stellar Object Q0353-383, J. A. Baldwin, F. Hamann, K. T. Korista, Gary J. Ferland, M. Dietrich, C. Warner

Physics and Astronomy Faculty Publications

The intensity of the strong N V λ1240 line relative to C IV λ1549 or to He II λ1640 has been proposed as an indicator of the metallicity of quasi-stellar object (QSO) broad emission line regions, allowing abundance measurements in a large number of QSOs out to the highest redshifts. Previously, it had been shown that the (normally) much weaker lines N III] λ1750 and N IV] λ1486 could be used in the same way. The redshift 1.96 QSO 0353-383 has long been known to have N III] and N IV] lines that are far stronger relative to Lyα or …

Radial Velocity Survey Of Members And Candidate Members Of The Tw Hydrae Association, Guillermo Torres, Eike W. Guenther, Laurence A. Marschall, Ralph Neuhauser, David W. Latham, Robert P. Stefanik

Physics and Astronomy Faculty Publications

We report spectroscopic observations of stars belonging to the young nearby group known as the TW Hydrae association, as well as of a number of potential members of the association identified in kinematic and X-ray surveys. Multiple radial velocity measurements were obtained for each object, several of which turn out to be multiple systems. Orbital solutions are presented for three double-lined binaries, one singlelined binary, and a double-lined triple system, all with short periods. Effective temperatures and projected rotational velocities are presented for each visible object. None of the candidate members of the association in our sample are confirmed as …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 19, Number 4, February 2003, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

New Jersey Coastal Program Boundary, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

The boundary of a federally approved coastal program defines a geographic area that receives special planning and management attention through regulations, financial assistance, and technical support. Section 306(d)(2)(A) of the federal Coastal Zone Management Act provides the basis for determining the coastal boundary. In Section 304 of the act, the coastal zone refers to coastal waters (and the lands below them) and the adjacent shorelands, “strongly influenced by each other and in proximity to the shorelines of the several coastal states, including transitional and intertidal areas, salt marshes, wetlands, and beaches. The zone extends…seaward to the outer limit of State …

Climatic Influences On Riverine Nitrate Flux: Implications For Coastal Marine Eutrophication And Hypoxia, Dubravko Justic, R. Eugene Turner, Nancy N. Rabalais

Faculty Publications

The average nitrate flux of the lower Mississippi River increased 3.3-fold between 1954–1967 and 1983–2000. During the same time period, the average nitrate concentration increased 2.3-fold while the average discharge increased 40%. Partitioning of the observed trend in nitrate flux among the two flux components, nitrate concentration and discharge, revealed that about 80% of the observed increase in flux could be explained by the increase in nitrate concentration. This indicates that a historical increase in the anthropogenic nutrient inputs has had a far greater impact on the lower Mississippi River nitrate flux than a change in climate. The influence of …

The Cohomology Of The Steendrod Algebra And Representations Of The General Linear Groups, Nguyen H. V. Hu'ng

Mathematics Research Reports

Let Tr_k be the algebraic transfer that maps from the coinvariants of certain GL_k-representation to the cohomology of the Steenrod algebra. This transfer was defined by W. Singer as an algebraic version of the geometrical transfer tr_k : pi_*^S((B[doublestrike V]_k)_+) --> pi_*^S(S^0). It has been shown that the algebraic transfer is highly nontrivial, more precisely, that Tr_k is an isomorphism for k = 1, 2, 3 and that T_r = ⊕_k(Tr_k) is a homomorphism of algebras.

In this paper, we first recognize the phenomenon that if we start from any degree d, and apply Sq^0 repeatedly at most (k- 2) …

Physica: The Newsletter Of Utep’S Department Of Physics, Utep Department Of Physics

The Department of Physics

Electronic newsletter of the UTEP Department of Physics, February 2003.

Designing Radiotherapy Plans With Elastic Constraints And Interior Point Methods, Allen G. Holder

Mathematics Faculty Research

A new linear programming model used to aid in the design of radiotherapy plans is introduced. This model incorporates elastic constraints, and when solved with a path following interior point method, produces favorable plans. A sound mathematical analysis shows how to interpret the solution, and hence, the treatment planner receives meaningful knowledge about the radiotherapy plan being developed. Preliminary experiments are conducted.

A Comprehensive Review Of The Ecological And Human Social Effects Of Artificial Feeding And Baiting Of Wildlife, L. Dunkley, M.R.L. Cattet

Canadian Cooperative Wildlife Health Centre: Newsletters and Publications

In recent years, events within Canada and the United States have drawn attention to potential negative consequences of feeding and baiting wild animals, especially enhanced transmission of infectious diseases such as bovine tuberculosis and chronic wasting disease. This report was prepared to gather available science-based information on the ecological and human social effects of artificial feeding and baiting of wildlife into one readily accessible document. The contracting agencies, Parks Canada and Saskatchewan Environment, recognize that an objective review of existing literature may help to answer questions and concerns within and outside the agencies, and help to guide subsequent decision-making concerning …

Smart Growth And Land Acquisition Priorities: A Cursory Review, New England Environmental Finance Center

Smart Growth

It is well-known and generally accepted that all undeveloped land in New England cannot forever be protected from development; nor would this be a desirable goal, as continued economic development and population growth are near certainties. For these and other reasons, private land trusts and government agencies generally use explicit criteria to prioritize their land acquisition activities and prospects.

Tcp Over Wireless Links: Mechanisms And Implications, Sonia Fahmy, Venkatesh Prabhakar, Srinivas R. Avasarafa, Ossama M. Younis

Department of Computer Science Technical Reports

No abstract provided.

Physics Department News, February 2003, College Of Arts And Sciences

Physics Newsletter

Contents from Volume 2, Issue 1:

• A Word From the Present Chair
• A Word From the Past Chair
• What’s New at the University
• Faculty Highlights
• PhysTEC
• New Faculty
• Alumni News
• Alumni Achievement Awards
• Annual Student Awards
• Recent Graduates
• Recent Guests
• Department Roster
• Photo Gallery
• Feedback/Update Reply Form

Analysis Of Several Eta Model Severe Weather Indices And Variable In Forecasting Severe Weather Across The High Plains, David Thede, Aaron Johnson

United States Department of Commerce: Staff Publications

Forecasting the onset of severe convective weather across the High Plains can be difficult. Topography differences from one end of a county warning area to the other can differ up to 5,000 feet. These topographical differences are not well handled by numerical weather prediction models (NWP) primarily due to insufficient horizontal resolution. The inability of NWP to accurately represent topography impacts the model depiction of the location and depth of low level moisture, an important contributor to convective instability. Convective Available Potential Energy (CAPE ) is a measure of the amount of energy available for convection. The computation of CAPE …

Web Mining For Web Personalization, Magdalini Eirinaki, Michalis Vazirgiannis

Magdalini Eirinaki

Web personalization is the process of customizing a Web site to the needs of specific users, taking advantage of the knowledge acquired from the analysis of the user's navigational behavior (usage data) in correlation with other information collected in the Web context, namely, structure, content, and user profile data. Due to the explosive growth of the Web, the domain of Web personalization has gained great momentum both in the research and commercial areas. In this article we present a survey of the use of Web mining for Web personalization. More specifically, we introduce the modules that comprise a Web personalization …

A Report On Impact Of Data Compression On Energy Consumption Of Wireless- -Networked Handheld Devices, Rong Xu, Zhiyuan Li, Cheng Wang, Peifeng Ni

Department of Computer Science Technical Reports

No abstract provided.

Genetic Variation In The Midcontinental Population Of Sandhill Cranes, Grus Canadensis, Jessica L. Petersen, Richard Bischof, Gary L. Krapu, Allen L. Szalanski

Nebraska Game and Parks Commission: Staff Research Publications

Three subspecies of sandhill crane (Grus canadensis) are recognized in the Midcontinental population, the lesser (Grus c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Blood samples collected on the population's primary spring staging area in Nebraska, U.S.A., were used to resolve the genetic relationship among these subspecies. Phylogenetic analysis of 27 G. canadensis, by DNA sequencing of a 675 bp region of the mtDNA, supports the subspecies designations of G. c. canadensisand G. c. tabida. G. c. rowani individuals were intermediate with each of the other two …

Habitat Utilization By Bottlenose Dolphins (Tursiops Truncatus) In Biscayne Bay, Florida, Christine A. Hudak

HCNSO Student Theses and Dissertations

Bottlenose dolphins (Tursiops truncatus) exhibit variable distribution patterns, depending upon their geographic location. Habitat utilization patterns in Biscayne Bay, Florida, were examined using the Biscayne Bay Bottlenose Dolphin Photo-ID database obtained from the National Oceanic and Atmospheric Administration (NOAA) Southeast Fisheries Science Center (SEFSC) Miami Laboratory. Habitat coverages in Biscayne Bay were obtained from the Atlas of Marine Resources Version 1.3B CD and the Biscayne Bay National Park CD. Dolphin sightings were overlaid on the habitat coverages using GIS Arcview software.

The effects of habitat, season, behavior, zone (sectioned area of Biscayne Bay), and depth on patterns …