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2002

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Articles 3301 - 3330 of 3435

Full-Text Articles in Physical Sciences and Mathematics

My Library At Virginia Commonwealth University: Third Year Evaluation, Jimmy Ghaphery Jan 2002

My Library At Virginia Commonwealth University: Third Year Evaluation, Jimmy Ghaphery

VCU Libraries Faculty and Staff Publications

My Library is a personalization tool that allows the library user to consolidate frequently used library resources and services. Since 1998, My Library has been available as a web page to users of the Virginia Commonwealth University Libraries. An evaluation of My Library use at Virginia Commonwealth University (VCU) was completed and published in 2000. This article reports on a follow up study that took place between March 2000 and December 2001. The article also discusses the value of My Library as a teaching tool at VCU.

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Effects Of Urbanization And Land Use On Pah Accumulation In Wetland Sediments, Kimani L. Kimbrough Jan 2002

Effects Of Urbanization And Land Use On Pah Accumulation In Wetland Sediments, Kimani L. Kimbrough

Dissertations, Theses, and Masters Projects

The relationship between wetland polycyclic aromatic hydrocarbon (PAH) concentrations and adjacent land use was assessed using surface sediments, sediment cores and global information systems (GIS) in the Elizabeth River, Virginia, an urbanized subestuary of the Chesapeake Bay. Wetlands adjacent to parking lots and petroleum industrial sites exhibited the highest PAH concentrations of all land uses in surfaces sediment and historically. Automobile and coal are the dominant sources of PAHs in wetland sediments historically as determined by relative concentration, fingerprinting and source specific compounds. An analysis of variance (ANOVA) test used to compare sixteen surface sediment sites based on land use …

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Organic Matter Cycling In The York River Estuary, Virginia: An Analysis Of Potential Sources And Sinks, Leigh Mccallister Jan 2002

Organic Matter Cycling In The York River Estuary, Virginia: An Analysis Of Potential Sources And Sinks, Leigh Mccallister

Dissertations, Theses, and Masters Projects

A study of the organic matter (OM) sources and biogeochemical and physicochemical sinks was undertaken in the York River estuary, Virginia. The reactivity of dissolved organic carbon (DOC) was enhanced from ∼25--68% by the combined effects of exposure to natural sunlight and bacterial decomposition. In contrast, sunlight exposure decreased the bioreactivity of DOC in the higher salinity lower York by a factor of five. The combined effects of photochemical and bacterial processing were found to modify both the bioavailability and metabolic fate of OM (e.g. respiration vs. biomass). Stable isotopic (delta13C, delta15N) and radiocarbon (Delta14C) values of bacterial nucleic acids …

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Genetic Stock Structure Of The Sailfish, Istiophorus Platypterus, Based On Nuclear And Mitochondrial Dna, Jan Renee Mcdowell Jan 2002

Genetic Stock Structure Of The Sailfish, Istiophorus Platypterus, Based On Nuclear And Mitochondrial Dna, Jan Renee Mcdowell

Dissertations, Theses, and Masters Projects

The results of life history studies involving the sailfish, Istiophorus platypterus, from the Atlantic, Pacific, and Indian oceans were reviewed. Results of studies agree on several aspects of sailfish biology; sailfish exhibit opportunistic feeding behavior, follow the 28??C isotherm, spawn in summer mature at approximately age 3, and are the least migratory of the billfishes. However, results are in conflict concerning sex ratio and whether sailfish are single or multiple spawners. Although many researchers have reported that sailfish are sexually dimorphic, their fragile otoliths make them difficult to age, aging studies have not been validated, and sexual dimorphism has not …

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Fate Of Organic Compounds Associated With Extractable And Bound Phases Of Estuarine Sediments Deposited Under Varying Depositional Regimes, Krisa Murray Arzayus Jan 2002

Fate Of Organic Compounds Associated With Extractable And Bound Phases Of Estuarine Sediments Deposited Under Varying Depositional Regimes, Krisa Murray Arzayus

Dissertations, Theses, and Masters Projects

Surficial sediments and sediment cores were collected from two distinct depositional regimes of the York River subestuary of Chesapeake Bay to document seasonal inputs, spatial variability, and longer-term (>40 years) fate of total organic carbon (TOC), lipid biomarker compounds and polycyclic aromatic hydrocarbons (PAHs). These regimes included biological mixing in the lower York and episodic mixing at the mid river site. Compounds were selected to represent a range of chemical reactivities, biological and anthropogenic sources, and modes of entry to the environment. The depositional environments were characterized with a suite of analytical tools: x-radiographs, Eh, 210Pb and 137Cs, total …

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Effects Of Habitat Fragmentation On The Utilization Of Eelgrass (Zostera Marina) By Mobile Epifauna And Macrofauna, Scott R. Marion Jan 2002

Effects Of Habitat Fragmentation On The Utilization Of Eelgrass (Zostera Marina) By Mobile Epifauna And Macrofauna, Scott R. Marion

Dissertations, Theses, and Masters Projects

The threat to biodiversity posed by increasing rates of anthropogenic habitat fragmentation necessitates an understanding of the consequences of spatial pattern for natural communities. Reduction of patch size, loss of habitat, changes in the quantity and proportion of habitat edge, and reduced connectivity among habitats can all shape ecological processes and faunal behavior. Seagrass habitats provide a natural model system for examining spatial inf1uences on marine fauna, but separating the effects of habitat structure, environmental conditions, and spatial pattern is difficult because shoot density, percent cover, and hydrodynamic regime often co-vary with patch size. This study used experimentally manipulated seagrass …

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Comparison Of The Fate Of Dissolved Organic Matter In Two Coastal Systems: Hog Island Bay, Va (Usa) And Plum Island Sound, Ma (Usa), Tami L. Lunsford Jan 2002

Comparison Of The Fate Of Dissolved Organic Matter In Two Coastal Systems: Hog Island Bay, Va (Usa) And Plum Island Sound, Ma (Usa), Tami L. Lunsford

Dissertations, Theses, and Masters Projects

No abstract provided.

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The Development Of A Water Quality Model In Baltimore Harbor, Back River, And The Adjacent Upper Chesapeake Bay, Hui Liu Jan 2002

The Development Of A Water Quality Model In Baltimore Harbor, Back River, And The Adjacent Upper Chesapeake Bay, Hui Liu

Dissertations, Theses, and Masters Projects

No abstract provided.

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Distribution, Fluxes, And Bacterial Utilization Of Different Molecular Weight Fractions Of Dissolved Organic Matter In The York River Estuary, Carol J. Pollard Jan 2002

Distribution, Fluxes, And Bacterial Utilization Of Different Molecular Weight Fractions Of Dissolved Organic Matter In The York River Estuary, Carol J. Pollard

Dissertations, Theses, and Masters Projects

No abstract provided.

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Nekton Utilization Of Intertidal Fringing Salt Marsh And Revetment Hardened Shorelines, Robert A. Carroll Jan 2002

Nekton Utilization Of Intertidal Fringing Salt Marsh And Revetment Hardened Shorelines, Robert A. Carroll

Dissertations, Theses, and Masters Projects

No abstract provided.

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Temporal And Spatial Variation In Reproductive Output Of The Veined Rapa Whelk (Rapana Venosa) In The Chesapeake Bay, Catherine C. Ware Jan 2002

Temporal And Spatial Variation In Reproductive Output Of The Veined Rapa Whelk (Rapana Venosa) In The Chesapeake Bay, Catherine C. Ware

Dissertations, Theses, and Masters Projects

No abstract provided.

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Diet Composition Of Young-Of-The-Year Bluefish, Pomatomus Saltatrix, In The Lower Chesapeake Bay And Virginia's Coastal Ocean, James Gartland Jan 2002

Diet Composition Of Young-Of-The-Year Bluefish, Pomatomus Saltatrix, In The Lower Chesapeake Bay And Virginia's Coastal Ocean, James Gartland

Dissertations, Theses, and Masters Projects

No abstract provided.

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An Evaluation Of Closed Area Boundaries Of The Sea Scallop Stock In The Middle Atlantic Bight, John David Lange Jan 2002

An Evaluation Of Closed Area Boundaries Of The Sea Scallop Stock In The Middle Atlantic Bight, John David Lange

Dissertations, Theses, and Masters Projects

No abstract provided.

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Estimating Commercial Scallop Dredge Efficiency Through Vessel Tracking, Catch Data, And Depletion Models, Todd Gedamke Jan 2002

Estimating Commercial Scallop Dredge Efficiency Through Vessel Tracking, Catch Data, And Depletion Models, Todd Gedamke

Dissertations, Theses, and Masters Projects

No abstract provided.

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Agmaps Land Manager Cd-Rom For The Frankland-Gordon Area, Tim D. Overheu, Angela Stuart-Street, Ron Master Jan 2002

Agmaps Land Manager Cd-Rom For The Frankland-Gordon Area, Tim D. Overheu, Angela Stuart-Street, Ron Master

Agmaps

This CD-ROM contains land resource maps and land management information relevant to the Frankland-Gordon area (Catchment Appraisal). It was produced by the Department of Agriculture. Also included on the CD is technical information which may now be out of date.

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Agmaps Land Profiler Cd-Rom For The Peel Region. Shires Of Boddington, Kwinana, Mandurah, Murray, Rockingham And Serpentine-Jarrahdale, Dennis Van Gool, Peter J. Tille, Ian Kininmonth, Philip M. Goulding Jan 2002

Agmaps Land Profiler Cd-Rom For The Peel Region. Shires Of Boddington, Kwinana, Mandurah, Murray, Rockingham And Serpentine-Jarrahdale, Dennis Van Gool, Peter J. Tille, Ian Kininmonth, Philip M. Goulding

Agmaps

This CD-ROM contains land resource maps and land management information for the Peel region. Shires of Boddington, Kwinana, Mandurah, Murray, Rockingham and Serpentine-Jarrahdale. It was produced by the Department of Agriculture Western Australia. Also included on the CD is technical information which may now be out of date.

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Coastal Zone Landscape Classification Using Remote Sensing And Model Development, Kevin R. Slocum Jan 2002

Coastal Zone Landscape Classification Using Remote Sensing And Model Development, Kevin R. Slocum

Dissertations, Theses, and Masters Projects

Coastal zone landscape characterization and empirical model development were evaluated using multi-spectral airborne imagery. Collectively, four projects are described that address monitoring and classification issues common to the resource management community. Chapter 1 discusses opportunities for remote sensing. Chapter 2 examines spectral and spatial image resolution requirements, as well as training sample selection methods required for accurate landscape classification. Classification accuracy derived from 25nm imagery with 4m pixel sizes outperformed 70nm imagery with 1m pixel sizes. Eight natural and five cultural landscape features were tested for classification accuracy. Chapter 3 investigated the ability to characterize 1m multispectral imagery into rank-ordered …

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The Ground State Of Two-Dimensional Hubbard-Like Models, Eric Christopher Allman Jan 2002

The Ground State Of Two-Dimensional Hubbard-Like Models, Eric Christopher Allman

Dissertations, Theses, and Masters Projects

We present results from a constrained path Monte Carlo (CPMC) study of a modified two-dimensional Hubbard model. We include more general forms of the band structure and electron interaction in order to examine their effects on ground-state properties, such as electron pairing correlations. Both next-nearest neighbor hopping, t', and third-nearest neighbor hopping, t″, are introduced in the Hamiltonian. A nearest neighbor interaction of strength V is also included. We carry out CPMC calculations on system sizes up to 16 x 16, at various electron fillings, to investigate the ground state of the model for different values of these parameters. For …

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Adaptive And Secured Resource Management In Distributed And Internet Systems, Li Xiao Jan 2002

Adaptive And Secured Resource Management In Distributed And Internet Systems, Li Xiao

Dissertations, Theses, and Masters Projects

The effectiveness of computer system resource management has been always determined by two major factors: (1) workload demands and management objectives, (2) the updates of the computer technology. These two factors are dynamically changing, and resource management systems must be timely adaptive to the changes. This dissertation attempts to address several important and related resource management issues.;We first study memory system utilization in centralized servers by improving memory performance of sorting algorithms, which provides fundamental understanding on memory system organizations and its performance optimizations for data-intensive workloads. to reduce different types of cache misses, we restructure the mergesort and quicksort …

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Simulation Techniques In An Artificial Society Model, Barry Glenn Lawson Jan 2002

Simulation Techniques In An Artificial Society Model, Barry Glenn Lawson

Dissertations, Theses, and Masters Projects

"Artificial society" refers to a generic class of agent-based simulation models used to discover global social structures and collective behavior produced by simple local rules and interaction mechanisms. Artificial society models are applicable in a variety of disciplines, including the modeling of chemical and biological processes, natural phenomena, and complex adaptive systems. We focus on the underlying simulation techniques used in artificial society discrete-event simulation models, including model time evolution and computational performance.;Although for some applications synchronous time evolution is the correct modeling approach, many other applications are better represented using asynchronous time evolution. We claim that asynchronous time evolution …

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Effects Of Longitudinal Disorder On The Magnetic Field Distribution In Bismuth Strontium Calcium Copper Oxide, Xuewen Wan Jan 2002

Effects Of Longitudinal Disorder On The Magnetic Field Distribution In Bismuth Strontium Calcium Copper Oxide, Xuewen Wan

Dissertations, Theses, and Masters Projects

Transverse Field muon spin relaxation (TF-muSR) experiments were performed in external magnetic fields 1.0, 2.7, 3.0, 4.5, 5.5, 6.0 and 7.0 T along the Bi2212 crystalline c-axis. For the first time, the heterodyned fitting analysis technique shows that the field profiles on the ab basal planes of single crystal Bi2212 are symmetric in all experimental fields 1.0--7.0 T and at all experimental temperatures 2.0-90.0 K. The muon spin relaxation rates due to the mixed state of Bi2212 were found to increase linearly from 0 mus-1 at the transition temperature, 90.0 K, to about 1.0 mus -1 at the lowest temperature, …

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Aggregate Matrix-Analytic Techniques And Their Applications, Alma Riska Jan 2002

Aggregate Matrix-Analytic Techniques And Their Applications, Alma Riska

Dissertations, Theses, and Masters Projects

The complexity of computer systems affects the complexity of modeling techniques that can be used for their performance analysis. In this dissertation, we develop a set of techniques that are based on tractable analytic models and enable efficient performance analysis of computer systems. Our approach is three pronged: first, we propose new techniques to parameterize measurement data with Markovian-based stochastic processes that can be further used as input into queueing systems; second, we propose new methods to efficiently solve complex queueing models; and third, we use the proposed methods to evaluate the performance of clustered Web servers and propose new …

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Simulation And Numerical Solution Of Stochastic Petri Nets With Discrete And Continuous Timing, Robert Linzey Jones Iii Jan 2002

Simulation And Numerical Solution Of Stochastic Petri Nets With Discrete And Continuous Timing, Robert Linzey Jones Iii

Dissertations, Theses, and Masters Projects

We introduce a novel stochastic Petri net formalism where discrete and continuous phase-type firing delays can appear in the same model. By capturing deterministic and generally random behavior in discrete or continuous time, as appropriate, the formalism affords higher modeling fidelity and efficiencies to use in practice. We formally specify the underlying stochastic process as a general state space Markov chain and show that it is regenerative, thus amenable to renewal theory techniques to obtain steady-state solutions. We present two steady-state analysis methods depending on the class of problem: one using exact numerical techniques, the other using simulation. Although regenerative …

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A Study Of The Influences Of Computer Interfaces And Training Approaches On End User Training Outcomes, Raj Gururajan Jan 2002

A Study Of The Influences Of Computer Interfaces And Training Approaches On End User Training Outcomes, Raj Gururajan

Theses: Doctorates and Masters

Effective and efficient training is a key factor in determining the success of end user computing (EUC) in organisations. This study examines the influences of two application interfaces, namely icons and menus, on training outcomes. The training outcomes are measured in terms of effectiveness, efficiency and perceived ease of use. Effectiveness includes the keystrokes used to accomplish tasks, the accuracy of correct keystrokes, backtracks and errors committed. Efficiency includes the time taken to accomplish the given tasks. Perceived ease of use rates the ease of the training environment including training materials, operating system, application software and associated resources provided to …

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Environment-Based Education: Policy, Practice, And Place, Eric N. Wickwire Jan 2002

Environment-Based Education: Policy, Practice, And Place, Eric N. Wickwire

All Master's Theses

The policies of the environment-based education movement are benefiting teachers and students participating in several model programs operating in the United States. Place-centered learning enhances the interdisciplinary practice of Essential Academic Learning Requirements, and actively engages students in local issues. The study of cultural landscapes encourages a sense of place within the Lower Columbia River Gorge, and fosters student connections with the Dalles Mountain Ranch. Policy recommendations are made for environment-based learning in Washington State's public schools. An example place-centered curriculum is outlined for practice at the Dalles Mountain Ranch, and a residential environmental learning center is proposed in the …

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Variation In The Position Of The Upwelling Front On The Oregon Shelf, Jay A. Austin, John A. Barth Jan 2002

Variation In The Position Of The Upwelling Front On The Oregon Shelf, Jay A. Austin, John A. Barth

CCPO Publications

As part of an experiment to study wind-driven coastal circulation, 17 hydrographic surveys of the middle to inner shelf region off the coast of Newport, OR (44.65°N, from roughly the 90 m isobath to the 10 m isobath) were performed during Summer 1999 with a small, towed, undulating vehicle. The cross-shelf survey data were combined with data from several other surveys at the same latitude to study the relationship between upwelling intensity and wind stress field. A measure of upwelling intensity based on the position of the permanent pycnocline is developed. This measure is designed so as to be insensitive …

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Estimating The Mean Ocean-Bay Exchange Rate Of The Chesapeake Bay, Jay A. Austin Jan 2002

Estimating The Mean Ocean-Bay Exchange Rate Of The Chesapeake Bay, Jay A. Austin

CCPO Publications

A model of the salt balance in the Chesapeake Bay is discussed, which takes into account only time-dependent riverine input and mean ocean-bay exchange. Estimates of (spatial) mean bay salinity are made using two different data sources: a 16 year record of surveys taken by the Environmental Protection Agency's Chesapeake Bay Program, and a 10 year record of hydrographic sections taken in the lower bay by the Center for Coastal Physical Oceanography at Old Dominion University. Using United States Geological Survey river flow data to force the model, both data sets are consistent with this simple model and both imply …

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The Northeast Pacific Globec Program: Coastal Gulf Of Alaska, Thomas J. Weingartner, Kenneth Coyle, Bruce Finney, Russell Hopcroft, Terry Whitledge, Richard Brodeur, Michael Dagg, Edward Farley, Dale Haidvogel, Thomas Royer Jan 2002

The Northeast Pacific Globec Program: Coastal Gulf Of Alaska, Thomas J. Weingartner, Kenneth Coyle, Bruce Finney, Russell Hopcroft, Terry Whitledge, Richard Brodeur, Michael Dagg, Edward Farley, Dale Haidvogel, Thomas Royer

CCPO Publications

(First Paragraph) The Gulf of Alaska (GOA) continental shelf encompasses approximately 370,000 km2, or about 13% of the U.S. continental shell and supports a rich and diverse marine ecosystem including some of the largest commercial fisheries in the U.S. Exclusive Economic Zone. Of particular economic importance is the salmon fishery, which was worth on the order of $170 million (landed value) in 2000 accrued from a catch of over 100 million fish. However, there is considerable variability on both interannual and longer time scales in harvest and recruitment success to this and other GOA fisheries. Of recent interest …

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Spatial And Temporal Patterns Of Eastern White Pine Regeneration In The Northwestern Ohio Oak Stand, Scott R. Abella, Neil W. Macdonald Jan 2002

Spatial And Temporal Patterns Of Eastern White Pine Regeneration In The Northwestern Ohio Oak Stand, Scott R. Abella, Neil W. Macdonald

Public Policy and Leadership Faculty Publications

Eastern white pine (Pinus strobus L.) was often associated with oaks (Quercus spp.) on upland sites in presettlement forests of the upper Great Lakes region, but widespread logging and subsequent fires in the late 1800s converted these upland sites to fire-tolerant oak forests. Although white pine regeneration is occurring in these second-growth oak forests, white pine regeneration patterns in oak forests of the Great Lakes region are not well documented. We examined white pine regeneration in the southern Great Lakes region in an oak stand within the Oak Openings region of northwestern Ohio, where white pine plantations established in the …

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Creating A User Friendly Website For The Boys & Girls Clubs Of Black Hawk County, Kimberly M. Carter Jan 2002

Creating A User Friendly Website For The Boys & Girls Clubs Of Black Hawk County, Kimberly M. Carter

Graduate Research Papers

Website design can be overwhelming for many viewers. Many times viewers discontinue using sites, because it.is not easy to navigate through the site. In creating the website for the Boys & Girls Clubs of Black Hawk County, user-friendliness was the focal point of the project. The Chief Professional Officer along with the staff at the Boys & Girls Clubs assisted with the development of a website by providing information that was to be included on the site. To ensure a professional look the designer relied on the four basic principles of design: contrast, repetition, alignment, and proximity. The design simplicity …

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