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Articles 1 - 30 of 45
Full-Text Articles in Physical Sciences and Mathematics
Predicting Future Shoreline Condition Based On Land Use Trends, Logistic Regression, And Fuzzy Logic, Lynne M. Dingerson
Predicting Future Shoreline Condition Based On Land Use Trends, Logistic Regression, And Fuzzy Logic, Lynne M. Dingerson
Dissertations, Theses, and Masters Projects
The lower Chesapeake Bay and adjacent coastal waters serve as the primary summer nursery areas for juvenile sandbar sharks (Carcharhinus plumbeus) in the Northwest Atlantic Ocean. The large population of juvenile sandbar sharks in this ecosystem benefits from increased food availability that fuels rapid growth and from limited exposure to large shark predators. Juvenile growth and survival is the most critical life history stage for sandbar sharks, and juvenile nursery grounds will continue to play an important role in the slow recovery of this stock from severe population declines due to overfishing. The goal of this study was to assess …
Planar Oxides As A Novel Approach To Metal Ion Sorption Studies: From The Lab To The Field, Christine F. Conrad
Planar Oxides As A Novel Approach To Metal Ion Sorption Studies: From The Lab To The Field, Christine F. Conrad
Dissertations, Theses, and Masters Projects
The purpose of this work is to investigate the use of planar oxides as tools for metal ion sorption studies that can be used in both laboratory and field settings. to do this, a three-step approach was used. In the first step, the reactivities of the planar gamma-Al2O3 surfaces relative to pure phase gamma alumina was investigated through Pb(II) sorption studies. The relative quantitative uptake of Pb(II) on the planar gamma alumina was found to be comparable to that on the bulk. XAS analysis showed that the coordination geometry and local binding environment of the Pb(II) complexes were similar on …
Effects Of Salinity And Nitrogen On The Distribution And Growth Of Phragmites Australis Along The Rappahannock River, Carmen Rebekah Packett
Effects Of Salinity And Nitrogen On The Distribution And Growth Of Phragmites Australis Along The Rappahannock River, Carmen Rebekah Packett
Dissertations, Theses, and Masters Projects
No abstract provided.
Synthesis And Characterization Of Hydrogen-Rich Polyimide Materials For Radiation Shielding, Sha Yang
Synthesis And Characterization Of Hydrogen-Rich Polyimide Materials For Radiation Shielding, Sha Yang
Dissertations, Theses, and Masters Projects
No abstract provided.
Effects Of Human Disturbance On The Breeding Success Of Eastern Bluebirds (Sialia Sialis), Caitlin Rebecca Kight
Effects Of Human Disturbance On The Breeding Success Of Eastern Bluebirds (Sialia Sialis), Caitlin Rebecca Kight
Dissertations, Theses, and Masters Projects
No abstract provided.
Eye Pathologies Found In Several Decapod Crustaceans, Andrea M. Maniscalco
Eye Pathologies Found In Several Decapod Crustaceans, Andrea M. Maniscalco
Dissertations, Theses, and Masters Projects
No abstract provided.
Application Of Survival Analysis Methods To Pulsed Exposures: Exposure Duration, Latent Mortality, Recovery Time, And The Underlying Theory Of Survival Distribution Models, Yuan Zhao
Dissertations, Theses, and Masters Projects
Ecotoxicologists adopted median lethal concentration (LC50) methods from mammalian toxicology. This conventional LC50 approach has shortcomings. Fixing the exposure duration and selecting the 50% mortality level result in loss of ecologically relevant information generated at all other times. It also ignores latent mortality that can manifest after exposure ends. as a result, it cannot adequately predict pulsed exposure effects in which concentration, duration, and frequency of pulses change through time. The underlying theory of the dose-response models used to calculate LC50 values, stochastic versus individual effective dose (IED) theory, has not been tested rigorously either. In this study, the effects …
Sources Of Sedimentary Organic Matter In The Mississippi River And Adjacent Gulf Of Mexico, Elizabeth J. Waterson
Sources Of Sedimentary Organic Matter In The Mississippi River And Adjacent Gulf Of Mexico, Elizabeth J. Waterson
Dissertations, Theses, and Masters Projects
The development of accurate carbon budgets, as well as global climate models with predictive capabilities, requires an understanding of the delivery and fate of terrigenous carbon in the environment. Understanding the extent to which estuarine and continental shelf processes alter carbon transfer between marine and terrestrial systems, including estimates of organic matter accumulation in coastal sediments, is poorly known. Organic carbon and nutrients exported to the adjacent Gulf of Mexico by the Mississippi River are influenced by biological and physical processes including remineralization, hydrodynamic sorting, seabed mixing and bioturbation, and burial. These complex processes make it difficult to know the …
Monte Carlo Simulations Of Ferroelectric Crystal Growth And Molecular Electronic Structure Of Atoms And Molecules, Malliga Suewattana
Monte Carlo Simulations Of Ferroelectric Crystal Growth And Molecular Electronic Structure Of Atoms And Molecules, Malliga Suewattana
Dissertations, Theses, and Masters Projects
In this thesis, we explore two stochastic techniques to study properties of materials in realistic systems. Specifically, the kinetic Monte Carlo (KMC) method is utilized to study the crystal growth process of ferroelectric materials and the quantum Monte Carlo (QMC) approach is used to investigate the ground state properties of atoms and molecules.;In the growth simulations, we study the growth rates and chemical ordering of ferroelectric alloys using an electrostatic model with long-range Coulomb interactions. Crystal growth is characterized by thermodynamic processes involving adsorption and evaporation, with solid-on-solid restrictions and excluding diffusion. A KMC algorithm is formulated to simulate this …
Distinguishing Sediment Transport Modes To The Outer-Shelf Off The Waiapu River, New Zealand, Lisa D. Addington
Distinguishing Sediment Transport Modes To The Outer-Shelf Off The Waiapu River, New Zealand, Lisa D. Addington
Dissertations, Theses, and Masters Projects
No abstract provided.
Hypoxia In Shallow Coastal Waters: A Case Study In Onancock Creek, Virginia, Taiping Wang
Hypoxia In Shallow Coastal Waters: A Case Study In Onancock Creek, Virginia, Taiping Wang
Dissertations, Theses, and Masters Projects
No abstract provided.
Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder
Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder
Dissertations, Theses, and Masters Projects
No abstract provided.
Reproductive Attributes Of Polynoid Polychaetes From Hydrothermal Vents On The East Pacific Rise, Jessica Lynn Wallace
Reproductive Attributes Of Polynoid Polychaetes From Hydrothermal Vents On The East Pacific Rise, Jessica Lynn Wallace
Dissertations, Theses, and Masters Projects
No abstract provided.
Iron And Carbon Limitation Of Prokaryotic Growth In The Ocean, Jacques L. Oliver
Iron And Carbon Limitation Of Prokaryotic Growth In The Ocean, Jacques L. Oliver
Dissertations, Theses, and Masters Projects
Studies were undertaken to examine the roles of iron and carbon in modulating prokaryotic growth in the ocean. The context of the first study was an open-open iron fertilization experiment in the high nutrient, low chlorophyll (HNLC) regime in the Southern Ocean. The context of the second study was the oligotrophic, iron-replete, and organic carbon-limited northwest Sargasso Sea. Experimental sea water cultures were amended with an iron chelator, desferrioxamine B (DFOB), and other nutrients to examine the effects of iron and carbon limitation on growth. In the first study prokaryotic abundance, carbon production, and growth rate increased in response to …
The Interaction Between Stratification, Circulation, And Sediment Transport In A Partially-Mixed Estuary, Malcolm E. Scully
The Interaction Between Stratification, Circulation, And Sediment Transport In A Partially-Mixed Estuary, Malcolm E. Scully
Dissertations, Theses, and Masters Projects
Detailed field observations from the York River estuary, Virginia are used to examine the processes governing vertical density stratification and to evaluate the importance of spatial and temporal variations in turbulent mixing on estuarine dynamics and sediment transport. Contrary to previous findings that suggest wind stress acts predominantly as a source of energy to mix away stratification, this study demonstrates that the wind can play a more important role in "straining" the along-channel estuarine density gradient. as a result, down-estuary winds enhance the tidally-averaged vertical shear, which interacts with the along-channel density gradient to increase stratification. Conversely, up-estuary winds tend …
Transfer Of Essential Fatty Acids By Marine Plankton, Adriana J. Veloza
Transfer Of Essential Fatty Acids By Marine Plankton, Adriana J. Veloza
Dissertations, Theses, and Masters Projects
Long chain n-3 polyunsaturated fatty acids (LCn-3 PUFAs) such as EPA and DHA are important biomolecules regulating production in marine ecosystems. This study examined how the interaction at the phytoplankton-zooplankton interface affected the transfer of LCn-3 PUFAs to higher trophic levels. Heterotrophic dinoflagellates contained higher levels of EPA and DHA than their algal prey, suggesting heterotrophic dinoflagellates enhanced the nutritional value of poor quality algae and subsequent transfer to the next trophic level. Formation of EPA and DHA in the dinoflagellates appears to be achieved by the elongation and desaturation of shorter fatty acid chains rather than through de novo …
Estimation Of Annual And Semi-Annual Survival Of Adult Female Blue Crabs And Assessment Of The Effectiveness Of The Virginia Blue Crab Sanctuary Using Tag-Return Methodology, Debra M. Lambert
Dissertations, Theses, and Masters Projects
The blue crab fishery is the most valuable commercial fishery in Chesapeake Bay. The Chesapeake Bay stock recently experienced a period of overfishing, which has resulted in below average abundances, and the spawning stock has experienced an 84 % decline in biomass relative to levels in the late 1980s. The status of the stock is determined by comparing current estimates of mortality to biological reference points. Given the current focus on blue crab conservation, there is a need to obtain reliable, empirical estimates of survival to compare to the biological reference points. A tagging program was initiated on the terminally-molted, …
Site Fidelity, Home Range, And Daily Movements Of White Perch, Morone Americana, And Striped Bass, Morone Saxatilis, In Two Small Tributaries Of The York River, Virginia, Patrick E. Mcgrath
Site Fidelity, Home Range, And Daily Movements Of White Perch, Morone Americana, And Striped Bass, Morone Saxatilis, In Two Small Tributaries Of The York River, Virginia, Patrick E. Mcgrath
Dissertations, Theses, and Masters Projects
Striped bass (Morone saxatilis) and white perch (M. americana) are two common species residing within Chesapeake Bay and its tributaries. These congeners are both commercially and recreationally important species. White perch are permanent residents in the Bay, while striped bass are only residents during the first few years of their life. During these initial years, striped bass co-occur with white perch. There is very little known about white perch and resident striped bass site fidelity and home range. This acoustic tagging study aims to examine site fidelity and home range of both species and determine if there is any spatial …
Meiofauna Abundance And Distribution In Chesapeake Bay: Relationships With Environmental Stressors, Sediment Toxicity And Macrofauna, William J. Metcalfe
Meiofauna Abundance And Distribution In Chesapeake Bay: Relationships With Environmental Stressors, Sediment Toxicity And Macrofauna, William J. Metcalfe
Dissertations, Theses, and Masters Projects
Macrofauna-based biocriteria to assess impairment in aquatic communities are well-developed and have been widely accepted as useful for coastal monitoring programs worldwide. Meiofauna-based methods are not as well developed, but meiofauna are intimately associated with sediments through their life cycles and are functionally important. Thus, an understanding of meiofauna relationships with environmental quality is also important. Relationships between the abundance and composition of major meiofauna taxa for two shallow water habitat types (protected, with muddy sediment; exposed, with sandy sediment) were investigated along gradients associated with changing land use, sediment contamination and environmental stressors in Chesapeake Bay. Principal component analysis …
Influence Of Environmental Factors On The Seed Ecology Of Vallisneria Americana, Jessie J. Campbell
Influence Of Environmental Factors On The Seed Ecology Of Vallisneria Americana, Jessie J. Campbell
Dissertations, Theses, and Masters Projects
Environmental conditions may positively or negatively influence production, reproduction, and restoration of submerged aquatic vegetation (SAV). As SAV populations decline, it is important to understand the potential impacts of the environment on the natural processes of reproduction. The objectives of this study are to provide fundamental information on sexual reproduction in a dominant species of freshwater SAV, Vallisneria americana, in the Chesapeake Bay observe the changes in environmental conditions in an established V. americana bed over an entire growing season (April-October), quantify the effects of similar environmental conditions on V. americana seed germination under controlled laboratory conditions, and finally to …
Modifications Of Spacetime And Particle Physics Beyond The Standard Model, Justin M. Conroy
Modifications Of Spacetime And Particle Physics Beyond The Standard Model, Justin M. Conroy
Dissertations, Theses, and Masters Projects
In this dissertation we consider spacetime modifications that result in new physics beyond the standard model. We investigate various collider implications of a particular Lorentz-conserving formulation of QED in which spacetime coordinates are noncommuting. We also consider collider implications of Universal Extra Dimensions. Specifically, we address the possible formation of bound states involving the first quark KK-modes, i.e. KK-quarkonium. In addition, we consider the use of boundary conditions in extra dimensions to break gauge symmetries in unified theories. These boundary conditions can be related to a boundary Higgs sector that decouples from the theory. This technique of "Higgsless" symmetry breaking …
Photochemical Modification Of Polyethylene Terephthalate Surface, Zhengmao Zhu
Photochemical Modification Of Polyethylene Terephthalate Surface, Zhengmao Zhu
Dissertations, Theses, and Masters Projects
The prospect of obtaining desired surface-mediated characteristics while retaining bulk-mediated physical properties and avoiding potential environmental issues with wet chemical technology lends considerable appeal to photochemical approaches to surface modification.;We undertook a combined experimental and computational approach to investigate the effect of deep UV irradiation on the polyethylene terephthalate (PET) surface. its response to 172 nm UV from a xenon examiner lamp in the absence of oxygen was characterized with X-ray Photoelectron Spectroscopy (XPS), Time of Flight/Secondary Ion Mass Spectrometry (ToF/SIMS), transmission infrared spectroscopy (IR), and Atomic Force Microscopy (AFM). The surface chemistry details suggested that the primary photochemical reactions …
Bi(Iii) Initiated Cyclization Reactions And Iodonium Fragmentation Kinetics, Yajing Lian
Bi(Iii) Initiated Cyclization Reactions And Iodonium Fragmentation Kinetics, Yajing Lian
Dissertations, Theses, and Masters Projects
No abstract provided.
Factory: A N Object-Oriented Parallel Programming Substrate For Deep Multiprocessors, Scott Arthur Schneider
Factory: A N Object-Oriented Parallel Programming Substrate For Deep Multiprocessors, Scott Arthur Schneider
Dissertations, Theses, and Masters Projects
No abstract provided.
Description And Evaluation Of The United States Coastal Pelagic Longline Fishery Interactions With Target And Non-Target Species In The Western North Atlantic, David. Kerstetter
Description And Evaluation Of The United States Coastal Pelagic Longline Fishery Interactions With Target And Non-Target Species In The Western North Atlantic, David. Kerstetter
Dissertations, Theses, and Masters Projects
Eighty-five monitored sets were used to investigate the interactions of pelagic fishes with commercial pelagic longline gear in the western North Atlantic during the fall mixed species fishery north of Cape Hatteras, North Carolina, and the spring swordfish fishery in the southern Gulf of Mexico and northern Caribbean Sea. This dissertation incorporates four components: (1) direct analyses of longline gear behavior using small time-depth recorders, (2) comparisons of catch rates and mortality of all species caught on size 16/0 non-offset circle and size 9/0 straight-shank J-style hooks, including analyses of time-of-capture utilizing electronic hook time recorders, (3) an evaluation of …
Simulation Of Turbidity Maximums In The York River, Virginia, Jae-Il Kwon
Simulation Of Turbidity Maximums In The York River, Virginia, Jae-Il Kwon
Dissertations, Theses, and Masters Projects
Two of the most important processes in cohesive sediment transport, erosion rate and settling velocity, were the focus of this study. Settling velocities were estimated by the Owen tube method and the acoustic Doppler velocimeter (ADV) method. A novel erosion model, namely a constant erosion rate model, was implemented in a three-dimensional hydrodynamic eutrophication model (HEM-3D) to simulate the turbidity maximums in the York River system, Virginia. Two one-month periods of model simulations were conducted to mimic typical dry (November--December, 2001) and wet (March--April, 2002) seasons. In order to have enough data to verify the model, four slack water surveys …
Tidal Wetland Contributions To Fecal Coliform Loads In Shellfish Growing Waters By Analysis Of Model Prediction Discrepancy, Jie. Huang
Dissertations, Theses, and Masters Projects
Fecal contamination in estuaries has become an increasing concern worldwide. The use of wetlands for wastewater treatment has expanded due to their natural ability to improve water quality by removing suspended sediments, nutrients, and fecal bacteria. In general, most of the removal occurs through deposition and accumulation in the wetland substrate. This would suggest that wetlands are effective filters for fecal coliform transported from terrestrial environments to surface waters. It has also been hypothesized, however, that wetlands may be an intermittent source of fecal coliform in tidal systems as a result of wildlife deposition and /or accumulation from terrestrial sources. …
Investigation Of The Life History Of The Cownose Ray, Rhinoptera Bonasus (Mitchill 1815), Donna S. Grusha
Investigation Of The Life History Of The Cownose Ray, Rhinoptera Bonasus (Mitchill 1815), Donna S. Grusha
Dissertations, Theses, and Masters Projects
No abstract provided.
A Molecular Phylogeny Of The Echeneoidea (Perciformes: Carangoidei) And An Investigation Of Population Structuring Within The Echeneidae, Kurtis N. Gray
A Molecular Phylogeny Of The Echeneoidea (Perciformes: Carangoidei) And An Investigation Of Population Structuring Within The Echeneidae, Kurtis N. Gray
Dissertations, Theses, and Masters Projects
No abstract provided.
Nursery Delineation, Movement Patterns, And Migration Of The Sandbar Shark, Carcharhinus Plumbeus, In The Eastern Shore Of Virginia Coastal Bays And Lagoons, Christina L. Conrath
Nursery Delineation, Movement Patterns, And Migration Of The Sandbar Shark, Carcharhinus Plumbeus, In The Eastern Shore Of Virginia Coastal Bays And Lagoons, Christina L. Conrath
Dissertations, Theses, and Masters Projects
The identification and delineation of nursery areas and areas of aggregation of north Atlantic sharks has been identified as an important information need for future management efforts. The objectives of this project were to use a fishery-independent method to study the overwintering area of juvenile sandbar sharks, to spatially delineate the Eastern Shore nursery area, and to examine movement patterns and space use within this nursery area. Data from 21 satellite transmitters attached to large juvenile sandbar sharks revealed that these sharks primarily occurred off the outer banks of North Carolina, at deeper depths and colder water temperatures during the …