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Articles 871 - 900 of 1876
Full-Text Articles in Physical Sciences and Mathematics
Nekton Utilization Of Intertidal Fringing Salt Marsh And Revetment Hardened Shorelines, Robert A. Carroll
Nekton Utilization Of Intertidal Fringing Salt Marsh And Revetment Hardened Shorelines, Robert A. Carroll
Dissertations, Theses, and Masters Projects
No abstract provided.
Temporal And Spatial Variation In Reproductive Output Of The Veined Rapa Whelk (Rapana Venosa) In The Chesapeake Bay, Catherine C. Ware
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.
Diet Composition Of Young-Of-The-Year Bluefish, Pomatomus Saltatrix, In The Lower Chesapeake Bay And Virginia's Coastal Ocean, James Gartland
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.
An Evaluation Of Closed Area Boundaries Of The Sea Scallop Stock In The Middle Atlantic Bight, John David Lange
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.
Estimating Commercial Scallop Dredge Efficiency Through Vessel Tracking, Catch Data, And Depletion Models, Todd Gedamke
Estimating Commercial Scallop Dredge Efficiency Through Vessel Tracking, Catch Data, And Depletion Models, Todd Gedamke
Dissertations, Theses, and Masters Projects
No abstract provided.
Coastal Zone Landscape Classification Using Remote Sensing And Model Development, Kevin R. Slocum
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 …
The Ground State Of Two-Dimensional Hubbard-Like Models, Eric Christopher Allman
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 …
Adaptive And Secured Resource Management In Distributed And Internet Systems, Li Xiao
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 …
Simulation Techniques In An Artificial Society Model, Barry Glenn Lawson
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 …
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, …
Aggregate Matrix-Analytic Techniques And Their Applications, Alma Riska
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 …
Simulation And Numerical Solution Of Stochastic Petri Nets With Discrete And Continuous Timing, Robert Linzey Jones Iii
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 …
A Numerical Simulation And Statistical Modeling Of High Intensity Radiated Fields Experiment Data, Laura Smith
A Numerical Simulation And Statistical Modeling Of High Intensity Radiated Fields Experiment Data, Laura Smith
Dissertations, Theses, and Masters Projects
No abstract provided.
Algorithms For Operations On Probability Distributions In A Computer Algebra System, Diane Lynn Evans
Algorithms For Operations On Probability Distributions In A Computer Algebra System, Diane Lynn Evans
Dissertations, Theses, and Masters Projects
In mathematics and statistics, the desire to eliminate mathematical tedium and facilitate exploration has lead to computer algebra systems. These computer algebra systems allow students and researchers to perform more of their work at a conceptual level. The design of generic algorithms for tedious computations allows modelers to push current modeling boundaries outward more quickly.;Probability theory, with its many theorems and symbolic manipulations of random variables is a discipline in which automation of certain processes is highly practical, functional, and efficient. There are many existing statistical software packages, such as SPSS, SAS, and S-Plus, that have numeric tools for statistical …
Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin
Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin
Dissertations, Theses, and Masters Projects
The interactive effects of humic acids (HAs) and salinity on the bioavailability and toxicity of the pesticides chlorpyrifos and 4,4'-dichlorodiphenyltrichloroethane (DDT) were investigated. The effects of various HAs on the toxicity of chlorpyrifos were initially assessed with the chronic MicrotoxRTM test. Environmentally relevant concentrations of Aldrich, Peat, Leonardite and Suwannee River HAs had no significant effect on the toxicity of either chlorpyrifos or copper (Cu), the test's positive control. as reductions in contaminant toxicity had previously been reported for some contaminants by HAs, it appeared that salinity might be a mitigating factor. Thus salinity effects were further investigated with Aldrich …
Molecular Characterization Of Cultured Perkinsus Marinus Isolates, Gwynne D. Brown
Molecular Characterization Of Cultured Perkinsus Marinus Isolates, Gwynne D. Brown
Dissertations, Theses, and Masters Projects
Perkinsus marinus is the causative agent of the oyster disease Dermo in the eastern oyster, Crassostrea virginica. In vitro propagation of the parasite has led to the establishment of multiple isolates by several investigators. Little work, however, has been done to characterize different isolates. In this study multiple isolates were examined for genetic and biochemical diversity. at two loci, the ITS region and the ATAN region, there was as much intra-isolate genetic variation among DNA sequences of some isolates as there was inter-isolate variation. Variation was also observed at a third loci, a subtilisin-like serine protease gene. This is the …
Use Of Pop-Up Satellite Tag Technology To Estimate Survival Of Blue Marlin (Makaira Nigricans) Released From Pelagic Longline Gear, David Kerstetter
Use Of Pop-Up Satellite Tag Technology To Estimate Survival Of Blue Marlin (Makaira Nigricans) Released From Pelagic Longline Gear, David Kerstetter
Dissertations, Theses, and Masters Projects
No abstract provided.
Spatial And Temporal Variability Of Physical And Biological Mixing In The York River Subestuary, Tara A. Kniskern
Spatial And Temporal Variability Of Physical And Biological Mixing In The York River Subestuary, Tara A. Kniskern
Dissertations, Theses, and Masters Projects
No abstract provided.
The Impact Of Marine Reserves On Exploited Species With Complex Life Histories: A Modeling Study Using The Caribbean Spiny Lobster In Exuma Sound, Bahamas, William T. Stockhausen
The Impact Of Marine Reserves On Exploited Species With Complex Life Histories: A Modeling Study Using The Caribbean Spiny Lobster In Exuma Sound, Bahamas, William T. Stockhausen
Dissertations, Theses, and Masters Projects
Most benthic invertebrates and reef-associated fish undergo a dispersive, planktonic larval stage prior to settlement and metamorphosis into the juvenile and adult stages. In some species, settlement may be decoupled from adult abundance at local spatial scales if hydrodynamic conditions or larval behavior do not promote local retention. Similarly, spatial variability in postsettlement mortality or secondary dispersal by juveniles and adults may decouple spatial patterns of adult abundance from those of settlement. as a consequence, spatial patterns of settlement and adult abundance may be functionally related in a complex fashion. Whether biotic/environmental factors control spatial patterns of abundance may have …
Phenomenology Of The Su(2)(L) X Su(2)(I) X U(1)(Y) X U(1)(Y') Model, Shuquan Nie
Phenomenology Of The Su(2)(L) X Su(2)(I) X U(1)(Y) X U(1)(Y') Model, Shuquan Nie
Dissertations, Theses, and Masters Projects
We consider the effective low-energy SU(2) L x SU(2)I x U(1)Y x U(1)Y' model, which is based on the E6 grand unification theory. SU(2)I is a subgroup of SU(3) R and commutes with the electric charge operator.;Higgs bosons in the Standard Model and two-Higgs doublet models are reviewed and studied first. The flavor-changing neutral currents and their effects on the anomalous magnetic moment of the muon are discussed. Bounds on masses of Higgs bosons are obtained by requiring that the vacuum is stable and perturbation theory is valid up to a large scale. We introduce Higgs multiplets including two neutral …
Sub-Pixel Techniques To Improve Spatial Resolution, Mark Robert Idema
Sub-Pixel Techniques To Improve Spatial Resolution, Mark Robert Idema
Dissertations, Theses, and Masters Projects
Image acquisition using a scene sampling device generally results in a loss of fidelity in the acquired image, particularly if the scene contains high frequency features. Acquired images are also degraded by the blurring effects of acquisition filtering, image reconstruction, and additive noise effects. to compensate for these degradations, a digital restoration filter that attempts to partially eliminate the blurring while avoiding amplification of the noise effects is needed. In addition, to compensate for undersampling, a subpixel technique known as microscanning is required. This dissertation provides research into the spatial resolution enhancement of digital images based on subpixel techniques that …
Preparation And Characterization Of Molecular Imprinting Polymer With (S)-Naproxen, Yue Hu
Preparation And Characterization Of Molecular Imprinting Polymer With (S)-Naproxen, Yue Hu
Dissertations, Theses, and Masters Projects
No abstract provided.
Heat Shock Protein (Hsp70) Response In The Eastern Oyster, Crassostrea Virginica, Exposed To Various Contaminants (Pahs, Pcbs And Cadmium), Luis A. Cruz Rodriguez
Heat Shock Protein (Hsp70) Response In The Eastern Oyster, Crassostrea Virginica, Exposed To Various Contaminants (Pahs, Pcbs And Cadmium), Luis A. Cruz Rodriguez
Dissertations, Theses, and Masters Projects
The stress protein response has been proposed as a general indicator of exposure to stress as their expression might integrate overall biological impact and interactions among multiple stressors. as a marker of contaminant effects, a major advantage is the premise of higher sensitivity over other indices such as condition index, scope for growth and survival. Laboratory exposure to suspended field contaminated sediments (SFCS) elicited a stress protein response (HSP70) in the eastern oyster, ( Crassostrea virginica). The stress response probably resulted from the combined effect of various contaminants including PAHs, metals and PCBs. Exposure to 1--2g suspended clay particles spiked …
Application Of The Genetic Algorithm To An Ecological Simulation, William J. Seufzer
Application Of The Genetic Algorithm To An Ecological Simulation, William J. Seufzer
Dissertations, Theses, and Masters Projects
A computational framework is built and demonstrated which is capable of testing plant growth strategies. The framework consists of Vgrass, a carbon based simulation model of a single Zostera marina plant, and the genetic algorithm (GA). Vgrass is based on published seagrass models, published photosynthetic data, and general plant physiology information. The model grows individual leaves whose initiation times are based on degree-day intervals. Leaf size is computed and combined with shoot density to compute population self shading. Leaf length is an emergent property since leaf growth is limited by light attenuation caused by self shading. The model is able …
Vitellogenin -- A Biomarker Of Exposure To Environmental Estrogens For Mummichog (Fundulus Heteroclitus) From A Creosote-Contaminated Site?, Sara Mirabilio
Vitellogenin -- A Biomarker Of Exposure To Environmental Estrogens For Mummichog (Fundulus Heteroclitus) From A Creosote-Contaminated Site?, Sara Mirabilio
Dissertations, Theses, and Masters Projects
Vitellogenin (VTG) is widely used as a biomarker for environmental estrogens and reproductive disruption in fish. Vitellogenesis is the process by which yolk is formed. The endpoint is most sensitive in male fish where vitellogenesis is an abnormal process. Research examining effects of environmental mixtures of chemicals (e.g. creosote) on vitellogenesis is limited. This study examines plasma VTG expression in both male and female mummichog, Fundulus heteroclitus, collected from a creosote-contaminated site and two reference sites in lower Chesapeake Bay, USA, and in wild-caught male reference fish exposed in the laboratory to creosote-contaminated sediment. Further, this study uses tissue somatic …
Growth Patterns Of Three Species Of Catfish (Ictaluridae) From Three Virginia Tributaries Of The Chesapeake Bay, William J. Connelly
Growth Patterns Of Three Species Of Catfish (Ictaluridae) From Three Virginia Tributaries Of The Chesapeake Bay, William J. Connelly
Dissertations, Theses, and Masters Projects
No abstract provided.
Assessment Of Development Impacts On Coastal Zone: Integrated Approach, Northampton County, Eastern Shore, Virginia, Sarunas Zableckis
Assessment Of Development Impacts On Coastal Zone: Integrated Approach, Northampton County, Eastern Shore, Virginia, Sarunas Zableckis
Dissertations, Theses, and Masters Projects
No abstract provided.
Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, John R. Foster
Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, John R. Foster
Dissertations, Theses, and Masters Projects
No abstract provided.
Nursery Delineation, Habitat Utilization, Movements, And Migration Of Juvenile Carcharhinus Plumbeus In Chesapeake Bay, Virginia, United States Of America, R. Dean. Grubbs
Dissertations, Theses, and Masters Projects
Chesapeake Bay is possibly the largest summer nursery for Carcharhinus plumbeus in the western Atlantic. Longline sampling conducted from 1990--1999 was used to delineate this nursery spatially and temporally. Catch data from 83 longline stations sampled throughout the Virginia Chesapeake Bay were analyzed as a function of nine physical and environmental variables to delineate this nursery spatially. Tree-based models determined which variables best discriminated between stations with high and low catches and indicated that complex distribution patterns could be adequately modeled with few variables. The highest abundance of juvenile sharks was predicted where salinity was greater than 20.5 and depth …
A Study Of The Secondary Turbidity Maximum In The York River Estuary, Virginia, Jing Lin
A Study Of The Secondary Turbidity Maximum In The York River Estuary, Virginia, Jing Lin
Dissertations, Theses, and Masters Projects
A two-year period of monthly slack water survey results suggest that in addition to the classical estuary turbidity maximum (ETM), a second peak of bottom total suspended sediments (TSS) concentration, or a secondary turbidity maximum (STM), often exists in the mid-York Estuary. This STM, detected from majority of the slack water surveys, moves back and forth in the region of about 20--40 km from the York River mouth. Moreover, the distribution of potential energy anomaly indicates that the STM may be related to the stratification patterns of the water column. A mathematical analysis suggests that four processes may be important …