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2003

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Articles 1951 - 1980 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Novel Pharmacophore Based Methods Reveal Gossypol As A Reverse Transcriptase Inhibitor, Paul A. Keller, C. Birch, S. P. Leach, D. Tyssen, R. Griffith Mar 2003

Novel Pharmacophore Based Methods Reveal Gossypol As A Reverse Transcriptase Inhibitor, Paul A. Keller, C. Birch, S. P. Leach, D. Tyssen, R. Griffith

Faculty of Science - Papers (Archive)

In a program to identify new structural entities for the inhibition of the HIV-1 reverse transcriptase (RT) enzyme via database searching, a series of RT pharmacophores were developed. By utilising a novel filtering technique, the National Cancer Institute database of compounds was scanned producing 15 compounds to be screened for activity. A notable inclusion was a series of gossypol derivatives. The testing of a series of compounds revealed the parent compound gossypol to be an HIV-1 reverse transcriptase inhibitor. These results suggest that at least part of its anti-HIV activity is due to gossypol targeting the non-nucleoside inhibitor binding pocket …


Self-Configuring Clusters, Data Aggregation And Authentication In Microsensor Networks, Maleq Khan, Bharat Bhargava, Leszek Lilien Mar 2003

Self-Configuring Clusters, Data Aggregation And Authentication In Microsensor Networks, Maleq Khan, Bharat Bhargava, Leszek Lilien

Department of Computer Science Technical Reports

No abstract provided.


Protection Of Application Service Hosting Platforms: An Operating System Perspective, Xuxian Jiang, Dongyan Xu Mar 2003

Protection Of Application Service Hosting Platforms: An Operating System Perspective, Xuxian Jiang, Dongyan Xu

Department of Computer Science Technical Reports

No abstract provided.


Stochastic Differential Systems With Memory (Spring School On Stochastic Delay Differential Equations), Salah-Eldin A. Mohammed Mar 2003

Stochastic Differential Systems With Memory (Spring School On Stochastic Delay Differential Equations), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

No abstract provided.


Arts And Sciences Newsletter, Volume 6, Issue 5, Pt. 2, College Of Arts & Sciences Mar 2003

Arts And Sciences Newsletter, Volume 6, Issue 5, Pt. 2, College Of Arts & Sciences

Arts and Sciences Newsletters

No abstract provided.


Dynamic Trust Production Based On Based On Interaction Sequence, Yuhui Zhong, Yi Lu, Bharat Bhargava Mar 2003

Dynamic Trust Production Based On Based On Interaction Sequence, Yuhui Zhong, Yi Lu, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.


X-Ray Spectral Diagnostics Of Neon Photoionization Experiments On The Z-Machine, David H. Cohen, J. J. Macfarlane, J. E. Bailey, D. A. Liedahl Mar 2003

X-Ray Spectral Diagnostics Of Neon Photoionization Experiments On The Z-Machine, David H. Cohen, J. J. Macfarlane, J. E. Bailey, D. A. Liedahl

Physics & Astronomy Faculty Works

We report on an initial spectroscopic study of low-density, x-ray photoionized neon with x-ray spectroscopy. These experiments, carried out on the Z-machine at Sandia, are optimized to produce a gradient-free, collisionless plasma, and to explore issues related to the rapid x-ray photoionization of relatively cold, low-density plasmas. The initial experiments used time-integrated absorption spectroscopy, backlit by the pinch radiation, to determine the ionization balance in the gas cell. Future experiments will use time-resolved spectroscopy in both absorption and emission. The emission spectra are expected to be similar to those seen from photoionized astrophysical sources, such as x-ray binaries. Indeed, in …


Disorder-Induced Rounding Of Certain Quantum Phase Transitions, Thomas Vojta Mar 2003

Disorder-Induced Rounding Of Certain Quantum Phase Transitions, Thomas Vojta

Physics Faculty Research & Creative Works

We study the influence of quenched disorder on quantum phase transitions in systems with overdamped dynamics. For Ising order-parameter symmetry disorder destroys the sharp phase transition by rounding because a static order parameter can develop on rare spatial regions. This leads to an exponential dependence of the order parameter on the coupling constant. At finite temperatures the static order on the rare regions is destroyed. This restores the phase transition and leads to a double exponential relation between critical temperature and coupling strength. We discuss the behavior based on Lifshitz-tail arguments and illustrate the results by simulations of a model …


X-Ray Emission Line Profile Modeling Of Hot Stars, Roban Hultman Kramer , '03, Stephanie Korinne Tonnesen , '03, David H. Cohen, S. P. Owocki, A. Ud-Doula, J. J. Macfarlane Mar 2003

X-Ray Emission Line Profile Modeling Of Hot Stars, Roban Hultman Kramer , '03, Stephanie Korinne Tonnesen , '03, David H. Cohen, S. P. Owocki, A. Ud-Doula, J. J. Macfarlane

Physics & Astronomy Faculty Works

The launch of high-spectral-resolution x-ray telescopes (Chandra, XMM) has provided a host of new spectralline diagnostics for the astrophysics community. In this paper we discuss Doppler-broadened emission line profiles from highly supersonic outflows of massive stars. These outflows, or winds, are driven by radiation pressure and carry a tremendous amount of kinetic energy, which can be converted to x rays by shock-heating even a small fraction of the wind plasma. The unshocked, cold wind is a source of continuum opacity to the x rays generated in the shock-heated portion of the wind. Thus the emergent line profiles are affected by …


Biology And Ecologyof Epigean Crayfish That Inhabit Everglades Environments Procambarus Alleni (Faxon) And Procambarus Fallax (Hagen), Peggy G. Vanarman Mar 2003

Biology And Ecologyof Epigean Crayfish That Inhabit Everglades Environments Procambarus Alleni (Faxon) And Procambarus Fallax (Hagen), Peggy G. Vanarman

HCNSO Student Theses and Dissertations

Two species of epigean crayfish, Procambarus alleni (the Everglades crayfish) and Procambarus fallax (slough crayfish), may be keystone species that inhabit wetlands in south Florida and the Everglades. Recent field studies showed that although these two species occur in sympatric and syntopic distribution, Everglades crayfish prefer shallow water and short hydroperiod conditions, whereas slough crayfish prefer areas that are more permanently flooded (Hendrix 2000). Slough crayfish have invaded some areas within the range occupied by Everglades crayfish, and may be the more successful competitor. Because of their critical role throughout the trophic structure of Everglades wetlands, shifts in relative abundance …


The Prairie Naturalist Volume 35, No.1 March 2003 Mar 2003

The Prairie Naturalist Volume 35, No.1 March 2003

The Prairie Naturalist

PATTERNS OF IMPALING IN A MIGRATORY POPULATION OF THE LOGGERHEAD SHRIKE ▪ J. D. Esely and E. K. Bollinger

COMPARISON OF FEEDING IN TWO PHENOLOGICALLY DISTINCT GRASSHOPPERS ▪ K. J. Haynes

DISTRIBUTION AND TRENDS OF BANDED CANADA GEESE IN SOUTH DAKOTA ▪ J. S. Gleason, J. A. Jenks, and P. W. Mammenga

FLORISTIC ASSESSMENT OF SAND PRAIRIES AND SEDGE MEADOWS, LEE COUNTY, ILLINOIS ▪ W. C. Handel, L. R. Phillippe, and J. E. Ebinger

POULT PROTECTION BY MERRIAM'S TURKEY FEMALES TOWARDS A NORTHERN GOSHAWK ▪ C. P. Lehman

ADDITIONAL ECTOPARASITIC RECORDS OF BATS FROM KANSAS ▪ D. W. Sparks, K. …


Arts And Sciences Newsletter, Volume 6, Issue 5, College Of Arts & Sciences Mar 2003

Arts And Sciences Newsletter, Volume 6, Issue 5, College Of Arts & Sciences

Arts and Sciences Newsletters

No abstract provided.


Farm Management Practice For The Prevention Of Soil Erosion In The Canarvon Horticulture Area, David Parr Mar 2003

Farm Management Practice For The Prevention Of Soil Erosion In The Canarvon Horticulture Area, David Parr

Horticulture research reports

Lower Gascoyne Management Strategy

The Carnarvon horticultural area has suffered considerable erosion damage following flooding of the Gascoyne River.

The purpose of this report is to describe the factors that contribute to soil erosion in the Carnarvon horticultural area (Section 1) and provide guidelines for soil management (Sections 2 and 3) which will assist farmers, local government planners and government bodies with responsibility for resource protection and conservation.

The report:

  • Provides detailed information on soil management for intensive irrigated cropping
  • Details cropping alternatives to better manage the soil erosion risk
  • Identifies appropriate plants for soil stabilisation in a range of …


Water-Quality Assessment Of The Central Nebraska Basins-— Enering A New Decade, Ronald B. Zelt, Jill D. Frankforter Mar 2003

Water-Quality Assessment Of The Central Nebraska Basins-— Enering A New Decade, Ronald B. Zelt, Jill D. Frankforter

United States Geological Survey: Publications

In 2001, the U.S. Geological Survey’s (USGS) National Water- Quality Assessment (NAWQA) Program began its second decade of intensive water-quality assessments (Cycle II). NAWQA scientists plan to revisit 42 major river-basin and aquifer systems (called study units) that were assessed in the first decade (Gilliom and others, 2001).


The Probe, Issue 227 – March/April 2003 Mar 2003

The Probe, Issue 227 – March/April 2003

The Probe: Newsletter of the National Animal Damage Control Association


• High-Tech Wolf Trapping -- Dexter K. Oliver
• The Wildlife Management Institute's booklet, Feeding Wildlife... Just Say No!, is back in stock.
• Owl Next Boxes & Rodent Control -- Robert H. Schmidt
• The terms of office for all the current NADCA officers and directors expires this year and an election must be called. NADCA president, Mike Conover, is asking for nominations to fill these positions.
• Call for Papers: 21st Vertebrate Pest Conference
• Britain Considers Eradicating Ruddy Duck Population: The British government is considering wiping out one species of duck to save another. The government and …


Dynamics Of Adsorbed Poly(Methyl Acrylate) And Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Wuu-Yung Lin, Crystal E. Porter Mar 2003

Dynamics Of Adsorbed Poly(Methyl Acrylate) And Poly(Methyl Methacrylate) On Silica, Frank D. Blum, Wuu-Yung Lin, Crystal E. Porter

Chemistry Faculty Research & Creative Works

Deuterium NMR and modulated differential scanning calorimetry (MDSC) were used to probe the behavior of ultrathin adsorbed poly(methyl acrylate) (PMA). The spectra for the bulk methyl-labeled PMA-d3 were consistent with the motions of the polymer segments being spatially homogeneous. For the polymers adsorbed on silica, multicomponent line shapes were observed. The segmental mobility of the surface polymers increased with increased adsorbed amounts. In contrast to the behavior of the polymers in bulk, the adsorbed lower-molecular-mass PMA-d3 was less mobile than the adsorbed high-molecular-mass polymer. The presence of a polymer overlayer was sufficient to suppress the enhanced mobility of the more-mobile …


Plasma-Etching-Enhanced Deep Centers In N-Gan Grown By Metalorganic Chemical-Vapor Deposition, Z-Q. Fang, David C. Look, X. L. Wang, J. Han, F. A. Khan, I. Adesida Mar 2003

Plasma-Etching-Enhanced Deep Centers In N-Gan Grown By Metalorganic Chemical-Vapor Deposition, Z-Q. Fang, David C. Look, X. L. Wang, J. Han, F. A. Khan, I. Adesida

Physics Faculty Publications

By using deep-level transient spectroscopy (DLTS), deep centers have been characterized in unintentionally doped n-GaN samples grown by metalorganic chemical-vapor deposition and subjected to inductively coupled plasma reactive ion etching. At least six DLTS traps exist in the control sample: A1 (∼0.90 eV), Ax (∼0.72 eV), B (0.61 eV), C1 (0.44 eV), D (0.25 eV), and E1 (0.17 eV), with B dominant. Then, as the etching bias-voltage increases from −50 to −150 V, trap D increases strongly and becomes dominant, while traps A1, C (0.34 eV), and E1 increase at a slower …


Wariness Of Coyotes To Camera Traps Relative To Social Status And Territory Boundaries, E.S. Sequin, Michael M. Jaeger, Peter F. Brussard, Reginald H. Barrett Mar 2003

Wariness Of Coyotes To Camera Traps Relative To Social Status And Territory Boundaries, E.S. Sequin, Michael M. Jaeger, Peter F. Brussard, Reginald H. Barrett

United States Department of Agriculture Wildlife Services: Staff Publications

The primary objective of this study was to develop a better understanding of coyote (Canis latrans) wariness particularly as it related to social status. We determined that territory status (controlling alpha, resident beta, or nonterritorial transient) affected vulnerability to photo-capture by infrared-triggered camera systems. All coyotes were wary of cameras, leading to relatively low numbers of photo-captures, most of which occurred at night. Alphas were significantly underrepresented in photographs and were never photo-captured inside their awn territories. Betas were photographed inside and outside their territories, whereas transients were most often photographed on edges of territories. Both alphas and …


Role Of The Tunneling Ray In Near-Critical-Angle Scattering By A Dielectric Sphere, James A. Lock Mar 2003

Role Of The Tunneling Ray In Near-Critical-Angle Scattering By A Dielectric Sphere, James A. Lock

Physics Faculty Publications

The scattering far zone for light transmitted through a sphere following p - 1 internal reflections by a family of near-grazing incident rays is subdivided into a lit region and a shadow region. The sharpness of the ray theory transition between the lit and the shadow regions is smoothed in wave theory by radiation shed by electromagnetic surface waves. It is shown that when higher-order terms in the physical optics approximation to the phase of the partial-wave scattering amplitudes are included, the transition between the lit and the shadow regions becomes a two-ray-to-zero-ray transition, called a superweak caustic in analogy …


High-Resolution Near-Field Raman Microscopy Of Single-Walled Carbon Nanotubes, Achim Hartschuh, X. Sunney Xie, Lukas Novotny, Erik J. Sánchez Mar 2003

High-Resolution Near-Field Raman Microscopy Of Single-Walled Carbon Nanotubes, Achim Hartschuh, X. Sunney Xie, Lukas Novotny, Erik J. Sánchez

Physics Faculty Publications and Presentations

We present near-field Raman spectroscopy and imaging of single isolated single-walled carbon nanotubes with a spatial resolution of approximately 25 nm. The near-field origin of the image contrast is confirmed by the measured dependence of the Raman scattering signal on tip-sample distance and the unique polarization properties. The method is used to study local variations in the Raman spectrum along a single single-walled carbon nanotube.


The Physical Interactions Between Hipco Swnts And Semi-Conjugated Polymers, Sinead Keogh, Theresa Hedderman, A. Maguire, M. G. Ruther, Elizabeth Gregan, Gordon Chambers, Hugh Byrne Mar 2003

The Physical Interactions Between Hipco Swnts And Semi-Conjugated Polymers, Sinead Keogh, Theresa Hedderman, A. Maguire, M. G. Ruther, Elizabeth Gregan, Gordon Chambers, Hugh Byrne

Conference papers

Hybrid systems of the conjugated organic polymer poly (p-phenylene vinylene-co-2,5- dioctyloxy -m-phenylene vinylene) (PmPV) and HiPco SWNT are explored using spectroscopic and thermal techniques to determine specific interactions. Vibrational spectroscopy indicates a weak interaction and this is further elucidated using Differential-Scanning Calorimetry and Temperature Dependent Raman pectroscopy. Two distinct transitions in region of -60C and + 60C are investigated.


Implementing An Information Retrieval And Visualization Framework For Heterogeneous Data Types, Andrew J. Kowalchuk Mar 2003

Implementing An Information Retrieval And Visualization Framework For Heterogeneous Data Types, Andrew J. Kowalchuk

Theses and Dissertations

In today's information focused world, there is no lack of entities focused on information gathering. However, there is still a widespread epidemic of information starvation in the Department of Defense (DoD). This starvation is attributed to the lack of interoperability between information gatherers and information consumers. To alleviate this problem, the DoD has put forth a vision of a Joint Battlespace Infosphere (JBI). This research proposes a framework for sharing and finding resources in a JBI. The framework uses an extensible metadata specification, agent technology, and the Control of Agent Based Systems (CoABS). It provides several tools for publication and …


Using Sequence Analysis To Perform Application-Based Anomaly Detection Within An Artificial Immune System Framework, Larissa A. O'Brien Mar 2003

Using Sequence Analysis To Perform Application-Based Anomaly Detection Within An Artificial Immune System Framework, Larissa A. O'Brien

Theses and Dissertations

The Air Force and other Department of Defense (DoD) computer systems typically rely on traditional signature-based network IDSs to detect various types of attempted or successful attacks. Signature-based methods are limited to detecting known attacks or similar variants; anomaly-based systems, by contrast, alert on behaviors previously unseen. The development of an effective anomaly-detecting, application based IDS would increase the Air Force's ability to ward off attacks that are not detected by signature-based network IDSs, thus strengthening the layered defenses necessary to acquire and maintain safe, secure communication capability. This system follows the Artificial Immune System (AIS) framework, which relies on …


Adjusting Sensing Range To Maximize Throughput On Ad-Hoc Multi-Hop Wireless Networks, Christopher K. Roberts Mar 2003

Adjusting Sensing Range To Maximize Throughput On Ad-Hoc Multi-Hop Wireless Networks, Christopher K. Roberts

Theses and Dissertations

The use of ad-hoc wireless networks is becoming common within the United States Air Force. Such networks are able to be implemented where traditional wired networks are either impractical or too expensive. As the miniaturization of communication devices continues, it is becoming increasingly common for mobile devices to communicate directly with each other, eliminating the need for center access points. Such a network is referred to as a multi-hop ad-hoc network, or simply a multi-hop network. Most multi-hop network protocols use some form of carrier sensing to determine if the wireless channel is in use. A large sensing range can …


The Effect Of Interactivity And Instructional Exposure On Learning Effectiveness And Knowledge Retention: A Comparative Study Of Two U.S. Air Force Computer-Based Training (Cbt) Courses For Network User Licensing, Matthew J. Imperial Mar 2003

The Effect Of Interactivity And Instructional Exposure On Learning Effectiveness And Knowledge Retention: A Comparative Study Of Two U.S. Air Force Computer-Based Training (Cbt) Courses For Network User Licensing, Matthew J. Imperial

Theses and Dissertations

The United States Air Force (USAF) currently employs the use of computer-based training (CET) across a host of requirements. One such requirement is in the Information Assurance (IA) arena and involves the training/licensing of over one-million computer network end-users. USAF use of CETs has been shown to possess a potential for substantial fiscal savings. However, studies investigating the learning outcomes of learning effectiveness (initial learning) and knowledge retention (sustained learning) associated with USAF CETs are lacking.


Data Mining Atmospheric/Oceanic Parameters In The Design Of A Long-Range Nephelometric Forecast Tool, Richard F. Benz Mar 2003

Data Mining Atmospheric/Oceanic Parameters In The Design Of A Long-Range Nephelometric Forecast Tool, Richard F. Benz

Theses and Dissertations

The Department of Defense calls for long-range forecasts to aid in the planning of operations. The goal of this research was to explore the feasibility of predicting, one month in advance, the total monthly cloud cover over the country of Afghanistan. In an attempt to reach this goal, the following objectives were achieved: (1) climatological synoptic study of Afghanistan; (2) survey of Real Time Nephanalysis, outgoing longwave radiation (OLR), and surface observational data; (3) examination of teleconnection indices and sea surface temperatures; (4) standard statistical analysis for prediction; and (5) classification tree analysis (CART), In addition, due to current world …


Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr. Mar 2003

Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr.

Theses and Dissertations

Modern semiconductor devices are principally made using the element silicon. In recent years, silicon carbide (SiC), with its wide band-gap, high thermal conductivity, and radiation resistance, has shown prospects as a semiconductor material for use in high temperature and radiation environments such as jet engines and satellites. A limiting factor in the performance of many SiC semiconductor components is the presence of lattice defects formed at oxide dielectric junctions during processing. Recent theoretical work has used small quantum mechanical systems embedded in larger molecular mechanics structures to attempt to better understand SiC surfaces and bulk materials and their oxidation. This …


Shortest Path Problems In A Stochastic And Dynamic Environment, Jae Il Cho Mar 2003

Shortest Path Problems In A Stochastic And Dynamic Environment, Jae Il Cho

Theses and Dissertations

In this research, we consider stochastic and dynamic transportation network problems. Particularly, we develop a variety of algorithms to solve the expected shortest path problem in addition to techniques for computing the total travel time distribution along a path in the network. First, we develop an algorithm for solving an independent expected shortest path problem. Next, we incorporate the inherent dependencies along successive links in two distinct ways to find the expected shortest path. Since the dependent expected shortest path problem cannot be solved with traditional deterministic approaches, we develop a heuristic based on the K-shortest path algorithm for this …


Hillslope Nutrient Dynamics Following Upland Riparian Vegetation Disturbance, J. Alan Yeakley, David C. Coleman, Bruce L. Haines, Brian D. Kloeppel, Judy L. Meyer, Wayne T. Swank, Barry W. Argo, James M. Deal, Sharon F. Taylor Mar 2003

Hillslope Nutrient Dynamics Following Upland Riparian Vegetation Disturbance, J. Alan Yeakley, David C. Coleman, Bruce L. Haines, Brian D. Kloeppel, Judy L. Meyer, Wayne T. Swank, Barry W. Argo, James M. Deal, Sharon F. Taylor

Environmental Science and Management Faculty Publications and Presentations

We investigated the effects of removing near-stream Rhododendron and of the natural blowdown of canopy trees on nutrient export to streams in the southern Appalachians. Transects were instrumented on adjacent hillslopes in a first-order watershed at the Coweeta Hydrologic Laboratory (35°03′N, 83°25′W). Dissolved organic carbon (DOC), K+, Na+, Ca2+, Mg2+, NO3-- -N, NH4+ -N, PO43---P, and SO42- were measured for 2 years prior to disturbance. In August 1995, riparian Rhododendron on one hillslope was cut, removing 30% of total woody biomass. In October …


Synthesis Of (+)-Decarestrictine L, Julie Lukesh, William Donaldson Mar 2003

Synthesis Of (+)-Decarestrictine L, Julie Lukesh, William Donaldson

Chemistry Faculty Research and Publications

A synthesis of (+)-decarestrictine L 1, a cholesterol biosynthesis inhibitory metabolite isolated from Penicillium simplicissimum, is described. Beginning from tri-O-acetyl- -glucal, alkylation with trimethylaluminum introduced the axial methyl group at C-2 in a stereoselective fashion. Chain extension at the C-6 carbon was accomplished by generation of the primary tosylate, followed by displacement with cyanide anion. The synthesis of (+)-1 was completed in 13 steps and 6.3% overall yield.