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Articles 751 - 780 of 1876
Full-Text Articles in Physical Sciences and Mathematics
Characteristics Of Vesicomyid Clams And Their Environment At The Blake Ridge Cold Seep, Taylor Perrine Heyl
Characteristics Of Vesicomyid Clams And Their Environment At The Blake Ridge Cold Seep, Taylor Perrine Heyl
Dissertations, Theses, and Masters Projects
No abstract provided.
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.
Markov Chain Modeling For Multi-Server Clusters, Zhili Hua
Markov Chain Modeling For Multi-Server Clusters, Zhili Hua
Dissertations, Theses, and Masters Projects
No abstract provided.
Data Broadcast Scheduling: Models, Algorithms, And Analysis, Aaron Thomas Hawkins
Data Broadcast Scheduling: Models, Algorithms, And Analysis, Aaron Thomas Hawkins
Dissertations, Theses, and Masters Projects
Inherent in the field of data broadcasting is a communication problem in which a server is to transmit a subset of data items in response to requests received from clients. The intent of the server is to optimize metrics quantifying the quality of service the system provides. This method of data dissemination has proved to be an efficient means of delivering information in asymmetric environments demanding massive scalability. of critical importance in such a system is the algorithm used by the server to construct a schedule of item broadcasts.;Due to the real-time nature of this problem, performances of heuristics designed …
Nuclear Magnetic Resonance Studies Of Relaxor Ferroelectrics, William J. Brouwer
Nuclear Magnetic Resonance Studies Of Relaxor Ferroelectrics, William J. Brouwer
Dissertations, Theses, and Masters Projects
This work is devoted to the study of local order in the ferroelectric PbSc1/2Ta1/2O3 (PST) and relaxor ferroelectric solid solutions (1-x)PbSC2/3W1/3O3-(x)PbTiO 3 (PSW-PT), (1x)PbSC2/3W1/3O3-(x)PbZrO 3 (PSW-PZ). Novel Magic Angle Spinning (MAS) Solid State Nuclear Magnetic Resonance (SS-NMR) experiments, including Multiple Quantum MAS (MQMAS) and Double Quantum Filtered Satellite Transition (DQF-STMAS), have been performed on these materials. A gamma function model is proposed for the distribution of quadrupole coupling constants, based on the Poissonian nature of atomic displacements. Moments for distributions may be subsequently extracted through agreement between experimental spectra and simulations implemented in novel programs. Simple crystal compound scandium oxide …
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 …
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.
Evaluating Restored Oyster Reefs In Chesapeake Bay: How Habitat Structure Influences Ecological Function, Janet A. Nestlerode
Evaluating Restored Oyster Reefs In Chesapeake Bay: How Habitat Structure Influences Ecological Function, Janet A. Nestlerode
Dissertations, Theses, and Masters Projects
A shortage of shell resources for restoring reefs of the Eastern oyster, Crassostrea virginica, has led to widespread use of substitute materials. The effectiveness of such alternative substrates as habitat for reef-associated fauna other than oysters is largely unresolved. I investigated the habitat value of oyster shell, surf clam (Spisula solidissima) shell, and pelletized coal ash reefs for benthic and nektonic communities. Oyster recruitment, survival, and growth were monitored on reefs of oyster and surf clam shell near the mouth of Chesapeake Bay and York River, USA. Oyster shell supported greater oyster growth and survival and offered the highest degree …
Complex Inner Shelf Environments: Observations And Modeling Of Morphodynamics And Scour Processes, Arthur C. Trembanis
Complex Inner Shelf Environments: Observations And Modeling Of Morphodynamics And Scour Processes, Arthur C. Trembanis
Dissertations, Theses, and Masters Projects
The inner continental shelf is a complex environmental system marked by sharp variations in bed roughness. Such heterogeneous systems account for 80% of the non-rocky inner shelves worldwide. Interactions among forces (waves, tides, turbulence, and bioturbation) and roughness elements (bed forms, rocks, and anthropogenic objects) exert major controls on sedimentary processes. This study attempts to advance the knowledge and understanding of the morphodynamics of the inner shelf. This study investigates scour and morphodynamic processes at Tairua, New Zealand; Cedar Island, Virginia; Indian Rocks Beach, Florida; and Beaufort Inlet, North Carolina. Using data from the field, the study develops new conceptual …
Pathobiology Of Mycobacteria In Striped Bass (Morone Saxatilis), David T. Gauthier
Pathobiology Of Mycobacteria In Striped Bass (Morone Saxatilis), David T. Gauthier
Dissertations, Theses, and Masters Projects
Striped bass (Morone saxatilis) in Chesapeake Bay, USA, are experiencing an epizootic of mycobacteriosis. This disease, caused by bacteria in the genus Mycobacterium, causes granulomatous lesions of the skin and viscera. Diseased fish are often emaciated, and fish with skin lesions may be significantly disfigured. The overall goal of this work was to examine aspects of the pathobiology of mycobacteria in striped bass via laboratory exposure studies and cellular assays. Striped bass were injected intraperitoneally with a sublethal dose of Mycobacterium marinum, M. shottsii, or M. gordonae and sampled for histology and bacteriology at regular intervals to 45 weeks post-injection …
On Certain Sets Of Matrices: Euclidean Squared Distance Matrices, Ray-Nonsingular Matrices And Matrices Generated By Reflections, Thomas W. Milligan
On Certain Sets Of Matrices: Euclidean Squared Distance Matrices, Ray-Nonsingular Matrices And Matrices Generated By Reflections, Thomas W. Milligan
Dissertations, Theses, and Masters Projects
In this dissertation, we study three different sets of matrices. First, we consider Euclidean distance squared matrices. Given n points in Euclidean space, we construct an n x n Euclidean squared distance matrix by assigning to each entry the square of the pairwise interpoint Euclidean distance. The study of distance matrices is useful in computational chemistry and structural molecular biology. The purpose of the first part of the thesis is to better understand this set of matrices and its different characterizations so that a number of open problems might be answered and known results improved. We look at geometrical properties …
Measurement Of The Branching Fraction For Neutral Kaon(Long) Decaying To Muon-Electron-Positron, Andrew J. Norman
Measurement Of The Branching Fraction For Neutral Kaon(Long) Decaying To Muon-Electron-Positron, Andrew J. Norman
Dissertations, Theses, and Masters Projects
This dissertation describes the measurement of the decay of the long lived neutral kaon into two muons and two electrons. The measurement was performed using the data taken during experiment E871 which was performed on the B5 beamline at the Alternating Gradient Synchrotron (AGS) of the Brookhaven National Laboratory (BNL). The branching ratio B( K0L → mu+mu-e +e-) is sensitive to the absorptive portion of the long distance amplitude for decays of the form K0L → ℓ+ℓ- and can be used to properly extract the short distance weak interaction amplitudes from the dileptonic events.;Measurement of K0L → mu+mu-e +e- additionally …
Dynamic Adaptation To Cpu And Memory Load In Scientific Applications, Richard Tran Mills
Dynamic Adaptation To Cpu And Memory Load In Scientific Applications, Richard Tran Mills
Dissertations, Theses, and Masters Projects
As commodity computers and networking technologies have become faster and more affordable, fairly capable machines have become nearly ubiquitous while the effective "distance" between them has decreased as network connectivity and capacity has multiplied. There is considerable interest in developing means to readily access such vast amounts of computing power to solve scientific problems, but the complexity of these modern computing environments pose problems for conventional computer codes designed to run on a static, homogeneous set of resources. One source of problems is the heterogeneity that is naturally present in these settings. More problematic is the competition that arises between …
An Economic Assessment Of Reducing Incidental Capture Of Sea Turtles In The Northwest Atlantic Pelagic Longline Fishery, Tara L. Scott
An Economic Assessment Of Reducing Incidental Capture Of Sea Turtles In The Northwest Atlantic Pelagic Longline Fishery, Tara L. Scott
Dissertations, Theses, and Masters Projects
No abstract provided.
Status And Demographic Analysis Of The Dusky Shark, Carcharhinus Obscurus, In The Northwest Atlantic, Jason G. Romine
Status And Demographic Analysis Of The Dusky Shark, Carcharhinus Obscurus, In The Northwest Atlantic, Jason G. Romine
Dissertations, Theses, and Masters Projects
No abstract provided.
Synthesis And Characterization Of Polyimide Residuum, Friable Balloons, Microspheres And Foams, Erik Saul Weiser
Synthesis And Characterization Of Polyimide Residuum, Friable Balloons, Microspheres And Foams, Erik Saul Weiser
Dissertations, Theses, and Masters Projects
In order to meet requirements of future NASA systems for advanced polymeric cellular materials, research was undertaken to develop the next generation of polyimide foams which could be utilized as a reusable structural insulation on future Reusable Launch Vehicle (RLV) Programs. This research activity focused on developing polyimide foam and foam structures which were made using monomeric solutions or salt solutions formed from the reaction of a dianhydride and diamine dissolved in a mixture of foaming agents and alkyl alcohols. This process produced a precursor solid residuum which could then be manufactured into foams, friable balloons and microspheres. Polyimide foams …
Survival And Habitat Preferences Of White Marlin (Tetrapturus Albidus) Released From The Western North Atlantic Recreational Fishery, Andrij Z. Horodysky
Survival And Habitat Preferences Of White Marlin (Tetrapturus Albidus) Released From The Western North Atlantic Recreational Fishery, Andrij Z. Horodysky
Dissertations, Theses, and Masters Projects
No abstract provided.
Control Of Integrable Hamiltonian Systems And Degenerate Bifurcations, Christopher W. Kulp
Control Of Integrable Hamiltonian Systems And Degenerate Bifurcations, Christopher W. Kulp
Dissertations, Theses, and Masters Projects
In this dissertation, we study the control of near-integrable systems. A near-integrable system is one whose phase space has a similar structure to an integrable system during short time periods and for some parameter regime. We begin by studying the control of integrable Hamiltonian systems. The controller targets an exact solution to the integrable system using dissipative and conservative terms. We find that a Takens-Bogdanov bifurcation occurs in the limit of no dissipative control. The presence of a Takens-Bogdanov bifurcation implies that the control is highly susceptible to noise. We illustrate our results using a two- and four-dimensional integrable systems …
Characterization Of Transient Behaviors In A Colliding Pulse Mode-Locked (Cpm) Laser, Wei Yang
Characterization Of Transient Behaviors In A Colliding Pulse Mode-Locked (Cpm) Laser, Wei Yang
Dissertations, Theses, and Masters Projects
A colliding pulse mode-locked (CPM) laser achieves sub-picosecond operation by synchronizing two counter-propagating pulse trains to form a standing wave in a thin absorber jet. When properly aligned, these lasers maintain mode-locking for more than 100 seconds (1010 pulses), but eventually cease mode-locking for short periods of time. This thesis examines the characteristics of these transient events, when CPM mode-locking ceases (dropout) and when it resumes (dropin). The dropout is an apparently rapid event, typically lasting no longer than 5 microseconds or less than 500 pulses. The dropin takes significantly longer time, often has structure, and has a clear power …
Dual Energy Scanning Beam X -Radiography, Randolph Frank Wojcik
Dual Energy Scanning Beam X -Radiography, Randolph Frank Wojcik
Dissertations, Theses, and Masters Projects
Dual energy X-radiography is a method first developed in the mid-1970's by which one uses the information contained in the energy spectrum of the transmitted X-ray flux through an object. With this information one can distinguish the types of materials present in a radiograph and thus allow a computer to subtract them from the image enhancing the contrast of the remaining materials. Using this method, one can see details, which would have been hidden by overlying structures of other materials such as seen in radiographs of parts, made up of mixtures of metals and composites. There is also great interest …
Bird Conservation Value Of Golf Courses, Joshua Elliott Leclerc
Bird Conservation Value Of Golf Courses, Joshua Elliott Leclerc
Dissertations, Theses, and Masters Projects
No abstract provided.
A Study Of The Eastern Oyster, Crassostrea Virginica: (1) Dermo Tolerance, Survival, Growth, Condition And Hsp70 Expression In Different Geographic Stocks; (2) Heat Tolerance And Effects Of Sublethal Heat Shock On Survival And Hsp70 Expression Of Infected And Uninfected Oysters, Vincent G. Encomio
Dissertations, Theses, and Masters Projects
The diseases Dermo and MSX have devastated Chesapeake Bay populations of the eastern oyster, Crassostrea virginica. The protozoan Perkinsus marinus, which causes Dermo, is particularly problematic since it persists over a wide range of salinities and temperatures. An objective of this dissertation was to determine whether specific wild oyster stocks had developed natural resistance to Dermo and if several parameters (survival, growth, condition and energy reserves) were associated with resistance. Another objective was to characterize heat shock protein (hsp70) expression in the eastern oyster. Heat shock proteins such as hsp70 protect organisms from thermal stress and other stressors, and this …
Natural Dermo Resistance And Related Defense Mechanisms In Eastern Oysters, Crassostrea Virginica, With Implications For Restoration, Shawn Michael Stickler
Natural Dermo Resistance And Related Defense Mechanisms In Eastern Oysters, Crassostrea Virginica, With Implications For Restoration, Shawn Michael Stickler
Dissertations, Theses, and Masters Projects
American oyster (Crassostrea virginica) stocks on the East Coast in general, and in Chesapeake Bay in particular, have been in decline over the past half-century in large part due to Dermo disease, caused by the protist parasite Perkinsus marinus. Efforts to restore oysters for their ecological and economic value have centered on the development and use of hatchery-based seed selectively bred for disease resistance. Selective breeding could benefit from the incorporation of oysters from wild stocks that have developed "natural Dermo resistance", but few such stocks have been identified and verified. This dissertation describes reciprocal common-garden experiments carried out at …
Vegetation Dynamics Of A Tidal Freshwater Marsh: Long-Term And Inter-Annual Variability And Their Relationship To Salinity, Sarah B. Davies
Vegetation Dynamics Of A Tidal Freshwater Marsh: Long-Term And Inter-Annual Variability And Their Relationship To Salinity, Sarah B. Davies
Dissertations, Theses, and Masters Projects
No abstract provided.
Reproductive Biology Of American Shad, Alosa Sapidissima, In The Mattaponi River, Aaron Reid Hyle
Reproductive Biology Of American Shad, Alosa Sapidissima, In The Mattaponi River, Aaron Reid Hyle
Dissertations, Theses, and Masters Projects
No abstract provided.
Metapopulation Dynamics, Habitat Quality, And Spatial Scale: Variation In Reproductive Output Of The Baltic Clam, Macoma Balthica, In Shallow Systems Of The Chesapeake Bay, Kristen Adams Delano
Metapopulation Dynamics, Habitat Quality, And Spatial Scale: Variation In Reproductive Output Of The Baltic Clam, Macoma Balthica, In Shallow Systems Of The Chesapeake Bay, Kristen Adams Delano
Dissertations, Theses, and Masters Projects
No abstract provided.
Parasitism In Deep-Sea Chemosynthetic Mussels: Parasitism In Bathymodiolus Mussels From Deep-Sea Seep And Hydrothermal Vents, Megan E. Ward
Parasitism In Deep-Sea Chemosynthetic Mussels: Parasitism In Bathymodiolus Mussels From Deep-Sea Seep And Hydrothermal Vents, Megan E. Ward
Dissertations, Theses, and Masters Projects
No abstract provided.
Assessing Anthropogenic And Natural Impacts On Ghost Crab ( Ocypode Quadrata) Populations At Cape Hatteras National Seashore, North Carolina, Cynthia B. Landry
Assessing Anthropogenic And Natural Impacts On Ghost Crab ( Ocypode Quadrata) Populations At Cape Hatteras National Seashore, North Carolina, Cynthia B. Landry
Dissertations, Theses, and Masters Projects
No abstract provided.
Ichthyofaunal And Dietary Analysis Of Sympatric Piscivores In A Chesapeake Bay Littoral Zone: Including Bioenergetic Models Of Growth And Diel Temperature Sanctuary Use, Christian Harding Hager
Ichthyofaunal And Dietary Analysis Of Sympatric Piscivores In A Chesapeake Bay Littoral Zone: Including Bioenergetic Models Of Growth And Diel Temperature Sanctuary Use, Christian Harding Hager
Dissertations, Theses, and Masters Projects
The first section of this dissertation describes the ichthyofaunal community of a mesohaline Chesapeake Bay April--November. Fish assemblages were sampled using two seine gears, a small seine that sampled 352 m 2 and a 914m haul-seine that sampled 144,473 m2. The small seine collected 32 finfish species. The larger gear captured 31 finfish species, including 17 that were not sampled by small gear. Sampled diversity was greater but density estimates were similar to those determined previously by other investigators using flume-net, drop-ring, and otter trawl techniques. Nocturnal abundance of larger fishes far exceeded daylight. Fish abundance and size distribution varied …