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Articles 1 - 30 of 36
Full-Text Articles in Physical Sciences and Mathematics
Habitat Utilization And Salinity Tolerance Of The Sandbar Shark, Carcharhinus Plumbeus, In Virginia, Leonard Pace
Habitat Utilization And Salinity Tolerance Of The Sandbar Shark, Carcharhinus Plumbeus, In Virginia, Leonard Pace
Dissertations, Theses, and Masters Projects
No abstract provided.
The Influence Of Predation On The Nesting Ecology Of Diamondback Terrapins (Malaclemys Terrapin) In The Lower Chesapeake Bay, Victoria Ann Ruzicka
The Influence Of Predation On The Nesting Ecology Of Diamondback Terrapins (Malaclemys Terrapin) In The Lower Chesapeake Bay, Victoria Ann Ruzicka
Dissertations, Theses, and Masters Projects
No abstract provided.
Novel Derivatizing Agents For The Determination Of Methylmercury By Gas Chromatography Using Electron Capture Detection, Crystal Marie Irwin
Novel Derivatizing Agents For The Determination Of Methylmercury By Gas Chromatography Using Electron Capture Detection, Crystal Marie Irwin
Dissertations, Theses, and Masters Projects
No abstract provided.
Size-Selectivity Of The Commercial Sea Scallop (Placopecten Magellanicus) Dredge: Evaluation The Performance Of The New Bedford Style Dredge Configured With 4-Inch Rings And A 10-Inch Twine Top Using The Select Model, Noelle Yochum
Dissertations, Theses, and Masters Projects
A size-selectivity curve was constructed to characterize the performance of the New Bedford style Atlantic sea scallop (Placopecten magellanicus) dredge when it is configured to meet the requirements of Amendment #10 to the Sea Scallop Fishery Management Plan. The curve was generated using the SELECT model on catch-at-length data, obtained by simultaneously towing a New Bedford style dredge and a non-selective National Marine Fisheries Service sea scallop survey dredge from commercial scallop vessels. Data were collected during three cruises in the Northwest Atlantic between 2005 and 2006. One cruise was completed in Georges Bank (Groundfish Closed Area II) and two …
Peroxynitrite Oxidation Of Aromatic Thiols: Characterization Of The Products Formed Through Oxidation Of Thionitrobenzoic Acid And Thionitropyridine By Peroxynitrite, Catherine Balchunas Mall
Peroxynitrite Oxidation Of Aromatic Thiols: Characterization Of The Products Formed Through Oxidation Of Thionitrobenzoic Acid And Thionitropyridine By Peroxynitrite, Catherine Balchunas Mall
Dissertations, Theses, and Masters Projects
No abstract provided.
Migratory And Spawning Behavior Of American Shad In The James River, Virginia, Aaron W. Aunins
Migratory And Spawning Behavior Of American Shad In The James River, Virginia, Aaron W. Aunins
Dissertations, Theses, and Masters Projects
No abstract provided.
Measurement Of Electroweak Asymmetries In Vector Electron Positron Scattering At 0.1 Less Than Q(2) Less Than 0.4 (Gev/C)(2), Jeffery A. Secrest
Measurement Of Electroweak Asymmetries In Vector Electron Positron Scattering At 0.1 Less Than Q(2) Less Than 0.4 (Gev/C)(2), Jeffery A. Secrest
Dissertations, Theses, and Masters Projects
This work is based on the first engineering run of the G 0 experiment from October 2002 though January 2003 in Hall C at Jefferson Lab. The G0 experiment will be the first to measure the weak neutral form factors: GEZ( Q2), GMZ( Q2) and GAe( Q2) and to extract the proton's strange form factors: GEs(Q2) and GMs(Q 2) via a Rosenbluth separation over a range of Q 2 (0.1--1.0 (GeV/c)2). This will require four sets of measurements: forward angle measurements with a proton target, and three sets of backward angle measurements with a hydrogen and deuterium target. The measurements …
Spectroscopy, Production And Decays Of Pentaquarks, Herry Kwee
Spectroscopy, Production And Decays Of Pentaquarks, Herry Kwee
Dissertations, Theses, and Masters Projects
An extensive study of the production, decay and spectroscopy of pentaquarks has been done in this dissertation. at the time of this writing, the existence of the pentaquark has not been conclusively established. New experimental results for the pentaquark will come in the months ahead. A brief review of the current experimental status of the pentaquark is given in the Introduction. The pentaquark states are analyzed using the constituent quark model with the lowest-lying pentaquark multiplet shown to be an antidecuplet. The mass splittings within the antidecuplet emerge from spin-color and spin-flavor interactions between constituents and from hidden strangeness in …
Physiological Consequences Of High Water Flow On The Coral Montastrea Annularis (Ellis And Solander, 1786), Lawrence W. Carpenter
Physiological Consequences Of High Water Flow On The Coral Montastrea Annularis (Ellis And Solander, 1786), Lawrence W. Carpenter
Dissertations, Theses, and Masters Projects
Water-flow is a vital component to the life histories of sessile marine invertebrates and essential to the structure and function of coral reefs. Recent studies have identified water-flow as an asset in the resistance to and recovery from short-term bleaching events of high irradiance and thermal increases. to determine whether the benefits of water-flow scale from the landscape level down to the flow patterns experienced over individual polyps and to quantify potential metabolic consequences, three studies were performed on Montastrea annularis (Ellis and Solander, 1786), using in situ heated bleaching flow-chambers during two saturation missions at the Aquarius underwater laboratory. …
Incorporating Space Into Stock Assessments Of Marine Species, John F. Walter
Incorporating Space Into Stock Assessments Of Marine Species, John F. Walter
Dissertations, Theses, and Masters Projects
Spatial management of marine resources requires population dynamic parameters in much greater spatial detail than traditional stock assessments provide. This dissertation presents a suite of methods to improve the spatial prediction of population abundance, fishing and natural mortality and to make greater use of commercial catch data. The main objectives of this dissertation are to determine the efficacy of using the vast amount of data collected by on-board observers on commercial vessels in model-based estimation of abundance and to use the spatial autocorrelation to improve resource mapping and abundance estimation. The first paper presents a methodology for improving variogram estimation …
Linking Land To Ocean: Flux And Fate Of Water And Sediment From The Yangtze River To The East China Sea, Kehui Xu
Dissertations, Theses, and Masters Projects
Although precipitation and runoff for the entire Yangtze River watershed have changed little since 1950, the increase of runoff in Yangtze southern sub-basin has been much larger than that of precipitation, reflecting decreased temperatures and evapotranspiration, In contrast, the marked decreases in runoff in northern Yangtze have been due mainly to increased water consumption. Since the 1980s, the Yangtze sediment load has declined dramatically, and 2004 loads at Yichang (just below the Three Gorges Dam - TGD) and Datong (lower stream) were only 12% and 33% of those in the 1950s and 60s, reflecting precipitation decline, landuse change, and most …
Sources And Composition Of Particulate Organic Matter In The Sacramento-San Joaquin River Delta, California, Vicki Pilon
Sources And Composition Of Particulate Organic Matter In The Sacramento-San Joaquin River Delta, California, Vicki Pilon
Dissertations, Theses, and Masters Projects
Determining organic matter sources and their availability to higher organisms is essential to better understanding the link between organic matter (OM) dynamics and secondary production, particularly in highly-disturbed river-delta systems. The San Francisco Bay and its associated Delta, is one of the most modified aquatic systems, and is the focus of an ongoing restoration effort. Particulate organic matter (POM) and surficial sediments were collected in the Sacramento-San Joaquin River Delta, CA to document temporal and spatial variations in biochemical, (total protein, carbohydrate and lipid), lipid biomarker, and total hydrolysable amino acid (THAA) composition. Sources, composition and nutritional quality of OM …
Sediment Biogeochemistry Of Northern Cascadia Margin Shallow Gas Hydrate Systems, John W. Pohlman
Sediment Biogeochemistry Of Northern Cascadia Margin Shallow Gas Hydrate Systems, John W. Pohlman
Dissertations, Theses, and Masters Projects
Methane contained in gas hydrate is a significant component of the global organic carbon inventory. Describing the methane sources supporting these systems and the mechanisms that control the distribution of methane in marine sediments are critical elements in evaluating the resource potential, climate change implications and geologic hazards associated with gas hydrate. The northern Cascadia margin (offshore Vancouver Island, Canada) is a convergent margin with gas hydrate-bearing cold seeps composed of both thermogenic (Barkley Canyon) and microbial (Bullseye vent) gas sources. Gas hydrate and sediment cores were collected from each of these settings to examine the sources that sustain the …
Physical Processes Behind Delta Propagation And Flood Layer Dynamics, Po River, Italy, Aaron J. Bever
Physical Processes Behind Delta Propagation And Flood Layer Dynamics, Po River, Italy, Aaron J. Bever
Dissertations, Theses, and Masters Projects
Rivers discharge around 20 billion tonnes of sediment to the coastal ocean each year (Milliman and Syvitski, 1992). Many supply dominated rivers possess large subareal and subaqueous deltas, whose growth depends on the physical processes controlling sediment deposition or removal. There has yet to be a complete understanding of how short term processes such as settling from buoyant plumes, wave/current resuspension, and transport by currents and gravity flows, interact to produce the depositional products that develop over varying timescales. The Po River in Northern Italy forms a substantial delta in the Adriatic Sea. It has five distributary mouths, and is …
Optical Characterization Of Ferromagnetic Heterostructure *Interfaces And Thin Films, Haibin Zhao
Optical Characterization Of Ferromagnetic Heterostructure *Interfaces And Thin Films, Haibin Zhao
Dissertations, Theses, and Masters Projects
This thesis presents optical characterizations of interfaces in ferromagnetic heterostructures and thin films used for spin polarized electronic devices. In these experiments, femtosecond laser spectroscopies are exploited to investigate the interface magnetization reversal, spin precession, and band offset, which are crucial in determining the performances of spintronic devices.;First, magnetization-induced second-harmonic-generation (MSHG) is applied to study interface magnetism in a hybrid structure containing a noncentrosymmetric semiconductor---Fe/AlGaAs. The reversal process of Fe interface layer magnetization is compared with the bulk magnetization reversal. In Fe/AlGaAs (001), the interface magnetization is found to be decoupled from the bulk magnetization based on the different switching …
The Effect Of Workload Dependence In Systems: Experimental Evaluation, Analytic Models, And Policy Development, Qi Zhang
Dissertations, Theses, and Masters Projects
This dissertation presents an analysis of performance effects of burstiness (formalized by the autocorrelation function) in multi-tiered systems via a 3-pronged approach, i.e., experimental measurements, analytic models, and policy development. This analysis considers (a) systems with finite buffers (e.g., systems with admission control that effectively operate as closed systems) and (b) systems with infinite buffers (i.e., systems that operate as open systems).;For multi-tiered systems with a finite buffer size, experimental measurements show that if autocorrelation exists in any of the tiers in a multi-tiered system, then autocorrelation propagates to all tiers of the system. The presence of autocorrelated flows in …
Development Of Generalized Index-Removal Models, With Particular Attention To Catchability Issues, Thomas F. Ihde
Development Of Generalized Index-Removal Models, With Particular Attention To Catchability Issues, Thomas F. Ihde
Dissertations, Theses, and Masters Projects
The index-removal method estimates abundance, exploitation and catchability coefficient, given surveys conducted before and after a known removal. The method assumes a closed population between surveys. Index-removal has seldom been applied due to its strong assumption of constant survey catchabilities. This work generalizes the method to allow multiple years of data to be incorporated, and the assumptions of the original model to be relaxed. If catchability is constant across years, precision can be improved by analyzing multi-year data simultaneously. Two multiple-year models were developed: the first, 1qIR, assumes constant catchability within and among years; the second, 2qIR, allows catchability to …
Development Of An Unstructured Grid, Finite Volume Eutrophication Model For The Shallow Water Coastal Bay: Application In The Lynnhaven River Inlet System, Yuepeng Li
Dissertations, Theses, and Masters Projects
The shallow water region is an important portion of the estuarine and coastal waters, since it encompasses the entire land-water margin as the buffer zone and supports one of the most productive ecosystems. When light can penetrate to the sediment, it triggers the benthic microalgae community to perform photosynthesis, resulting in a benthic-pelagic exchange flux different from that of the deeper water. This study utilized the laboratory-measured benthic flux, and a suite of well-calibrated numerical models to examine the eutrophication process in the Lynnhaven River Inlet system with special emphasis on: the role played by benthic microalgae, and nutrient budgets …
Diel And Site-Specific Feeding Of Young Striped Bass In A Heterogeneous Nursery Habitat, Sarah C. Muffelman
Diel And Site-Specific Feeding Of Young Striped Bass In A Heterogeneous Nursery Habitat, Sarah C. Muffelman
Dissertations, Theses, and Masters Projects
The Chesapeake Bay spawning stock of striped bass, Morone saxatilis, is considered one of the largest sources of juvenile production along the Atlantic coast and exhibits a high degree of interannual recruitment variability. Year class strength is judged by near-shore seine surveys that cover major tributaries of Chesapeake Bay and survey results are incorporated into annual stock assessments. In these surveys, the contribution of the Rappahannock River (Virginia) to total production is significant. In this system, abundance of juveniles is highest at a single seine site, suggesting that juvenile production may be related to habitat heterogeneity and food availability. To …
A Molecular Technique For Specific Identification Of Western Atlantic Ocean Scombrids And An Analysis Of A Larval Scombrid Assemblage Off The Kona Coast Of Hawaii, Melissa A. Paine
A Molecular Technique For Specific Identification Of Western Atlantic Ocean Scombrids And An Analysis Of A Larval Scombrid Assemblage Off The Kona Coast Of Hawaii, Melissa A. Paine
Dissertations, Theses, and Masters Projects
No abstract provided.
Ultrafast Laser Spectroscopy Of Half -Metallic Chromium Dioxide, Hailong Huang
Ultrafast Laser Spectroscopy Of Half -Metallic Chromium Dioxide, Hailong Huang
Dissertations, Theses, and Masters Projects
This thesis presents ultrafast laser pump-probe differential transmission experiments on epitaxial CrO2 (110). The experiments were conducted at the wavelengths of 600 nm, 800 nm and 1200 nm, corresponding to the transition energies of 2 eV, 1.5 eV and 1 eV respectively. The wavelength dependent results, comparing with linear optical absorption, revealed the electronic structure of the material. The experimental results also showed polarization dependence of the probe beams. This is attributed to the electronic orbital anisotropy.;Temperature dependence was observed in the pump-probe experiments. The ultrafast transmission data show similar temperature dependence as ultrafast MOKE (Magneto-Optical Kerr Effect) data. A …
Passive Available Bandwidth: Applying Self -Induced Congestion Analysis Of Application-Generated Traffic, Marcia Zangrilli Bryan
Passive Available Bandwidth: Applying Self -Induced Congestion Analysis Of Application-Generated Traffic, Marcia Zangrilli Bryan
Dissertations, Theses, and Masters Projects
Monitoring end-to-end available bandwidth is critical in helping applications and users efficiently use network resources. Because the performance of distributed systems is intrinsically linked to the performance of the network, applications that have knowledge of the available bandwidth can adapt to changing network conditions and optimize their performance. A well-designed available bandwidth tool should be easily deployable and non-intrusive. While several tools have been created to actively measure the end-to-end available bandwidth of a network path, they require instrumentation at both ends of the path, and the traffic injected by these tools may affect the performance of other applications on …
Developing A Stock Assessment For The Barndoor Skate (Dipturus Laevis) In The Northeast United States, Todd Gedamke
Developing A Stock Assessment For The Barndoor Skate (Dipturus Laevis) In The Northeast United States, Todd Gedamke
Dissertations, Theses, and Masters Projects
The barndoor skate Dipturus laevis is one of seven species in the United States Northwest Atlantic skate complex. The species received little attention until a recent article published in Science reported that the barndoor skate might be on the brink of extinction. In this study, we address not only the virtual lack of information on the life history of the species, but also develop methodologies to assist in the assessment of the barndoor skate population. to investigate the life history of the species, data were collected from 2,310 specimens caught during commercial sea scallop dredging in the southern section of …
Disposition Of Wastewater-Associated Polybrominated Diphenyl Ethers In A Freshwater Receiving Stream, Mark Joseph La Guardia
Disposition Of Wastewater-Associated Polybrominated Diphenyl Ethers In A Freshwater Receiving Stream, Mark Joseph La Guardia
Dissertations, Theses, and Masters Projects
No abstract provided.
Studies In Cpt Violation And 331 Models, David L. Anderson
Studies In Cpt Violation And 331 Models, David L. Anderson
Dissertations, Theses, and Masters Projects
The Standard Model of particles and fields has been around for about 30 years, and has been remarkably successful. However, it is widely believed to be incomplete, and theorists have studied various extensions to the model. These extensions can take many forms. An example of this is the framework Colladay and Kostelecky have proposed for studying Lorentz and CPT violation in a natural extension of the Standard Model. We determined the first bounds on the parameters in the Higgs sector. The bounds on the CPT---even asymmetric coefficients arise from the one-loop contributions to the photon propagator, those from the CPT---even …
Carbon Nanosheets And Carbon Nanotubes By Rf Pecvd, Mingyao Zhu
Carbon Nanosheets And Carbon Nanotubes By Rf Pecvd, Mingyao Zhu
Dissertations, Theses, and Masters Projects
A planar antenna RF plasma enhanced chemical vapor deposition apparatus was built for carbon nanostructure syntheses. When operated in inductive and capacitive plasma discharging modes, two carbon nanostructures, carbon nanotube (CNT) and carbon nanosheet (CNS), were synthesized, respectively.;A nanosphere lithography method was developed and used to prepare catalyst patterns for CNT growth. Using capacitively coupled C2H2/NH 3 plasma, randomly oriented CNT were synthesized on Ni dot patterned Si substrates. Aligned CNT arrays were grown on SiO2 coated Si substrates, using both C2H2/NH3 and CH 4/H2 capacitive plasmas.;When operated in inductive coupling mode, CNS were successfully deposited on a variety of …
Automated Peak Identification For Time -Of -Flight Mass Spectroscopy, Haijian Chen
Automated Peak Identification For Time -Of -Flight Mass Spectroscopy, Haijian Chen
Dissertations, Theses, and Masters Projects
The high throughput capabilities of protein mass fingerprints measurements have made mass spectrometry one of the standard tools for proteomic research, such as biomarker discovery. However, the analysis of large raw data sets produced by the time-of-flight (TOF) spectrometers creates a bottleneck in the discovery process. One specific challenge is the preprocessing and identification of mass peaks corresponding to important biological molecules. The accuracy of mass assignment is another limitation when comparing mass fingerprints with databases.;We have developed an automated peak picking algorithm based on a maximum likelihood approach that effectively and efficiently detects peaks in a time-of-flight secondary ion …
Internal Magnetic Field Distribution Of A Type Ii High Tc Superconductor With Non-Conducting Inclusions, Yuxin Dai
Dissertations, Theses, and Masters Projects
The internal magnetic field distributions for a type II superconductor (a single crystal YBa2Cu3O7-delta ) with large normal inclusions (YBa2Cu3O 7-delta) are studied. A model based on the London Equations has been successfully developed and applied to the interpretation of the pSR data on this system. In our model, these inclusions are assumed to be cylindrical in shape and infinite in length. Therefore, this model should be especially appropriate for the prediction of field distributions in single crystal superconductors in which columnar defects have been purposely introduced to enhance pinning.;muSR experiments on a large single-crystal sample of YBa2C u3O7-delta with …
Time-Resolved Magneto-Optical Imaging Of Superconducting Ybco Thin Films In The High-Frequency Ac Current Regime, Alexander Frey
Time-Resolved Magneto-Optical Imaging Of Superconducting Ybco Thin Films In The High-Frequency Ac Current Regime, Alexander Frey
Dissertations, Theses, and Masters Projects
No abstract provided.
Community Structure And Biogeography Of Mussel Bed Communities At Pacific Hydrothermal Vents: Lau And North Fiji Back-Arc Basins, 32° S---East Pacific Rise, And 38° S---Pacific Antarctic Ridge, Elizabeth Anne Blake
Community Structure And Biogeography Of Mussel Bed Communities At Pacific Hydrothermal Vents: Lau And North Fiji Back-Arc Basins, 32° S---East Pacific Rise, And 38° S---Pacific Antarctic Ridge, Elizabeth Anne Blake
Dissertations, Theses, and Masters Projects
No abstract provided.