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Articles 1 - 30 of 47
Full-Text Articles in Physical Sciences and Mathematics
Survival In An Urbanized Landscape: Radio-Tracking Fledgling Eastern Bluebirds (Sialia Sialis) On Golf Courses, Allyson Kathleen Jackson
Survival In An Urbanized Landscape: Radio-Tracking Fledgling Eastern Bluebirds (Sialia Sialis) On Golf Courses, Allyson Kathleen Jackson
Dissertations, Theses, and Masters Projects
No abstract provided.
A Measurement Of The Neutron Electric Form Factor At Very Large Momentum Transfer Using Polarized Electrons Scattering From A Polarized Helium-3 Target, Aidan Michael Kelleher
A Measurement Of The Neutron Electric Form Factor At Very Large Momentum Transfer Using Polarized Electrons Scattering From A Polarized Helium-3 Target, Aidan Michael Kelleher
Dissertations, Theses, and Masters Projects
Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q2 and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized 3He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. GEn was measured …
Copepod Carcasses, Mortality And Population Dynamics In The Tributaries Of The Lower Chesapeake Bay, David Thomas. Elliott
Copepod Carcasses, Mortality And Population Dynamics In The Tributaries Of The Lower Chesapeake Bay, David Thomas. Elliott
Dissertations, Theses, and Masters Projects
Several studies have documented the occurrence of substantial numbers of zooplankton carcasses in marine field samples. However, the potential effect of carcasses on conclusions resting on zooplankton abundance estimates, and the reasons for carcass occurrence have been largely disregarded. Many field studies do not account for the presence of carcasses in their sampling methodology. Zooplankton carcasses in situ are significant for several reasons. as concentrated particles of organic matter in the water column, zooplankton carcasses can be important vehicles for organic matter transport and hotspots of microbial abundance and activity. If dead animals are treated alive, carcasses could bias the …
Habitat Complexity And Habitat Function Of Native (Crassostrea Virginica) And Non-Native (C. Ariakensis) Oysters In The Chesapeake Bay Region, Heather D. Harwell
Habitat Complexity And Habitat Function Of Native (Crassostrea Virginica) And Non-Native (C. Ariakensis) Oysters In The Chesapeake Bay Region, Heather D. Harwell
Dissertations, Theses, and Masters Projects
Complex oyster reefs created by the Eastern oyster, Crassostrea virginica, though once prominent features of the Chesapeake Bay region, have become relatively scarce in comparison to historic descriptions. This decline, caused by a combination of overfishing, disease, habitat destruction and pollution, this decline continues despite substantial restoration efforts that have spanned decades. In response to this decline, the states of Virginia and Maryland considered the intentional introduction of the non-native Suminoe oyster, C. ariakensis. Previous studies questioned the reef-building capability of this Crassostrea species, which may affect its habitat function. Through a combination of field and mesocosm studies, I examined …
Characterization And Deposition Of Aerosol Organic Matter In The Eastern United States, Andrew S. Wozniak
Characterization And Deposition Of Aerosol Organic Matter In The Eastern United States, Andrew S. Wozniak
Dissertations, Theses, and Masters Projects
Aerosol organic carbon (OC) was characterized in two eastern United States watersheds to investigate the potential importance of aerosol OC in watershed OC budgets and cycling. Fluxes of 1.7 and 2.1 mg aerosol OC m-2 d-1 were measured for aerosol samples in Harcum, VA and Millbrook, NY, respectively. Scaled to the area of nearby watersheds (York River watershed, VA and Hudson River watershed, NY) these fluxes are similar in magnitude or greater than the magnitude of riverine OC exported by corresponding rivers indicating that aerosols must be taken into account when thinking about biogeochemical exchanges between the atmospheric, terrestrial, and …
Applications Of Pattern Classification To Time-Domain Signals, Crystal Ann Bertoncini
Applications Of Pattern Classification To Time-Domain Signals, Crystal Ann Bertoncini
Dissertations, Theses, and Masters Projects
Many different kinds of physics are used in sensors that produce time-domain signals, such as ultrasonics, acoustics, seismology, and electromagnetics. The waveforms generated by these sensors are used to measure events or detect flaws in applications ranging from industrial to medical and defense-related domains. Interpreting the signals is challenging because of the complicated physics of the interaction of the fields with the materials and structures under study. often the method of interpreting the signal varies by the application, but automatic detection of events in signals is always useful in order to attain results quickly with less human error. One method …
Adaptive Learning And Cryptography, David Goldenberg
Adaptive Learning And Cryptography, David Goldenberg
Dissertations, Theses, and Masters Projects
Significant links exist between cryptography and computational learning theory. Cryptographic functions are the usual method of demonstrating significant intractability results in computational learning theory as they can demonstrate that certain problems are hard in a representation independent sense. On the other hand, hard learning problems have been used to create efficient cryptographic protocols such as authentication schemes, pseudo-random permutations and functions, and even public key encryption schemes.;Learning theory / coding theory also impacts cryptography in that it enables cryptographic primitives to deal with the issues of noise or bias in their inputs. Several different constructions of "fuzzy" primitives exist, a …
The Logarithmic Method And The Solution To The Tp2-Completion Problem, Shahla Nasserasr
The Logarithmic Method And The Solution To The Tp2-Completion Problem, Shahla Nasserasr
Dissertations, Theses, and Masters Projects
A matrix is called TP2 if all 1-by-1 and 2-by-2 minors are positive. A partial matrix is one with some of its entries specified, while the remaining, unspecified, entries are free to be chosen. A TP2-completion, of a partial matrix T , is a choice of values for the unspecified entries of T so that the resulting matrix is TP2. The TP2-completion problem asks which partial matrices have a TP2-completion. A complete solution is given here. It is shown that the Bruhat partial order on permutations is the inverse of a certain natural partial order induced by TP2 matrices and …
Advancements In Dual-Pump Broadband Cars For Supersonic Combustion Measurements, Sarah Augusta. Tedder
Advancements In Dual-Pump Broadband Cars For Supersonic Combustion Measurements, Sarah Augusta. Tedder
Dissertations, Theses, and Masters Projects
Space- and time-resolved measurements of temperature and species mole fractions of nitrogen, oxygen, and hydrogen were obtained with a dual-pump coherent anti-Stokes Raman spectroscopy (CARS) system in hydrogen-fueled supersonic combustion free jet flows. These measurements were taken to provide time-resolved fluid properties of turbulent supersonic combustion for use in the creation and verification of computational fluid dynamic (CFD) models. CFD models of turbulent supersonic combustion flow currently facilitate the design of air- breathing supersonic combustion ramjet (scramjet) engines. Measurements were made in supersonic axi-symmetric free jets of two scales. First, the measurement system was tested in a laboratory environment using …
Enhancing Web Browsing Security, Chuan Yue
Enhancing Web Browsing Security, Chuan Yue
Dissertations, Theses, and Masters Projects
Web browsing has become an integral part of our lives, and we use browsers to perform many important activities almost everyday and everywhere. However, due to the vulnerabilities in Web browsers and Web applications and also due to Web users' lack of security knowledge, browser-based attacks are rampant over the Internet and have caused substantial damage to both Web users and service providers. Enhancing Web browsing security is therefore of great need and importance.;This dissertation concentrates on enhancing the Web browsing security through exploring and experimenting with new approaches and software systems. Specifically, we have systematically studied four challenging Web …
Integrating Space-And Time-Scales Of Sediment-Transport For Poverty Bay, New Zealand, Aaron J. Bever
Integrating Space-And Time-Scales Of Sediment-Transport For Poverty Bay, New Zealand, Aaron J. Bever
Dissertations, Theses, and Masters Projects
Poverty Bay is a small embayment located in the middle of the Waipaoa River Sedimentary Dispersal System (WSS) on the eastern coast of the north island of New Zealand. Within this dispersal system, a large multidisciplinary study was focused on determining the sediment routing from the source within the headwaters to the locations of sediment accumulation on the continental shelf and slope. Poverty Bay acts as the land to sea transition area in the WSS, and as such significantly modifies the fluvial sedimentary signal before it is exported to the continental shelf. Until this study, little hydrodynamic or sediment-transport work …
Observations Of Storm Morphodynamics Using Coastal Lidar And Radar Imaging System (Claris): Importance Of Wave Refraction And Dissipation Over Complex Surf-Zone Morphology At A Shoreline Erosional Hotspot, Katherine L. Brodie
Dissertations, Theses, and Masters Projects
Elevated water levels and large waves during storms cause beach erosion, overwash, and coastal flooding, particularly along barrier island coastlines. While predictions of storm tracks have greatly improved over the last decade, predictions of maximum water levels and variations in the extent of damage along a coastline need improvement. In particular, physics based models still cannot explain why some regions along a relatively straight coastline may experience significant erosion and overwash during a storm, while nearby locations remain seemingly unchanged. Correct predictions of both the timing of erosion and variations in the magnitude of erosion along the coast will be …
Incorporating Industry Based Dredge Surveys Into The Assessment Of Sea Scallops, Placopecten Magellanicus, David B. Rudders
Incorporating Industry Based Dredge Surveys Into The Assessment Of Sea Scallops, Placopecten Magellanicus, David B. Rudders
Dissertations, Theses, and Masters Projects
Cooperative research utilizing industry vessels represents a viable approach to acquire the data necessary to meet the increasing needs associated with the modern management of marine resources. This dissertation addresses a variety of topics associated with the integration of commercial vessels into the stock assessment of the sea scallop, Placopecten magellanicus. In this study we evaluate the efficacy of utilizing industry vessels with respect to topics that range from rotational closed area survey design, sampling gear evaluation as well as an experiment that broadens the scale of the traditional use of industry vessels in this fishery and provides data to …
The Role Of Copepods And Heterotrophic Dinoflagellates In The Production Of Dissolved Organic Matter And Inorganic Nutrients, Grace Kathleen Saba
The Role Of Copepods And Heterotrophic Dinoflagellates In The Production Of Dissolved Organic Matter And Inorganic Nutrients, Grace Kathleen Saba
Dissertations, Theses, and Masters Projects
Zooplankton play a key role in the cycling of dissolved organic matter (DOM) and inorganic nutrients. The factors that affect these processes, however, are not fully understood. I measured the effects of various diets on DOM and inorganic nutrient production by the copepod Acartia tonsa and the heterotrophic dinoflagellate Oxyrrhis marina, and explored the mechanisms of nutrient release from copepods. Copepods feeding on a mixed diet, the preferred diet of most copepods, had significantly lower dissolved organic carbon (DOC), ammonium (NH4+), and total dissolved nitrogen (TDN) release rates compared to feeding on a carnivorous or herbivorous diet. Thus, copepod feeding …
Accounting For Undesirable Outputs In Productivity Measurements: Application To The California-Oregon Drift Gillnet Fishery, Tara L. Scott
Accounting For Undesirable Outputs In Productivity Measurements: Application To The California-Oregon Drift Gillnet Fishery, Tara L. Scott
Dissertations, Theses, and Masters Projects
Many production activities typically produce undesirable outputs, e.g., the production of the pollutant sulfur dioxide in the generation of electricity. Traditional economic metrics may overstate the efficiency and productivity of these production activities by failing to account for the undesirable outputs. These omissions can lead to conclusions that are biased against resource conservation and protection. Many fisheries capture their target species concomitantly with undesirable outputs such as bycatch of juvenile fish, marine mammals, sea birds, and sea turtles. One such fishery is the California-Oregon (CA/OR) drift gillnet fishery (DGNF), which incidentally takes protected species, such as sea turtles and marine …
Bioavailability Of Biosolids- And Consumer Product-Associated Polybrominated Diphenyl Ether (Pbde) Flame Retardants To Terrestrial Invertebrates, Michael O. Gaylor
Bioavailability Of Biosolids- And Consumer Product-Associated Polybrominated Diphenyl Ether (Pbde) Flame Retardants To Terrestrial Invertebrates, Michael O. Gaylor
Dissertations, Theses, and Masters Projects
The primary objectives of this research were therefore to evaluate polybrominated diphenyl ether (PBDE) bioavailability to ecologically distinct soil invertebrates exposed to Penta-BDE-treated consumer polyurethane foam (PUF) products and biosolid products with incurred PBDEs. In laboratory bioassays, earthworms (Eisenia fetida) bioaccumulated SigmaPBDEs (47+99+100+183) up to 11,000 mug/kg lipid after 28 days from a mixture of artificial soil and anaerobically-digested sludge biosolid (ADB). Earthworms also bioaccumulated SigmaPBDEs (47+99+100+153+154+183) up to 13,500 and 838,000 mug/kg lipid after 28 d from a mixture of artificial soil and composted sludge biosolid (CB) and Penta-BDE-spiked artificial soil (SAS), respectively. No previous lab studies on bioaccumulation …
Persistent Organic Pollutants(Pops) As Tracers Of Environmental Change And Antarctic Seabird Ecology, Heidi N. C. Geisz
Persistent Organic Pollutants(Pops) As Tracers Of Environmental Change And Antarctic Seabird Ecology, Heidi N. C. Geisz
Dissertations, Theses, and Masters Projects
Antarctic seabirds including Adelie penguins (Pygoscelis adeliae), south polar skuas (Catharacta maccormicki), southern giant petrels (Macronectes gigantus) are high trophic level predators that accumulate persistent organic pollutants (POPs) present in the food webs in which they forage. Little is known about the levels of POPs in some Antarctic organisms (e.g. southern giant petrels), as well as the long-term trends of POPs in the Antarctic ecosystem. Samples from all three seabird species were collected post mortem, including eggs, from the Western Antarctic Peninsula (WAP) and in the Ross Sea throughout the austral summer breeding seasons of 2004--2006. The samples were analyzed …
Spatial And Temporal Patterns In Erosional And Depositional Processes: Physical And Biological Controls In The York River, Chesapeake Bay, Virginia, Cielomar Rodríguez-Calderon
Spatial And Temporal Patterns In Erosional And Depositional Processes: Physical And Biological Controls In The York River, Chesapeake Bay, Virginia, Cielomar Rodríguez-Calderon
Dissertations, Theses, and Masters Projects
No abstract provided.
Assessing The Functional Status Of Created Wetlands In Eastern Virginia Via A Soil And Vegetative Developmental Trajectory, Sara Elizabeth Kreisel
Assessing The Functional Status Of Created Wetlands In Eastern Virginia Via A Soil And Vegetative Developmental Trajectory, Sara Elizabeth Kreisel
Dissertations, Theses, and Masters Projects
No abstract provided.
"You Have No Boss Here To Work For": Women And Labor In Chesapeake Bay Fishing Communities, Elizabeth Marie O'Grady
"You Have No Boss Here To Work For": Women And Labor In Chesapeake Bay Fishing Communities, Elizabeth Marie O'Grady
Dissertations, Theses, and Masters Projects
No abstract provided.
Processing And Conversion Of Algae To Bioethanol, Sara Katherine Kampfe
Processing And Conversion Of Algae To Bioethanol, Sara Katherine Kampfe
Dissertations, Theses, and Masters Projects
No abstract provided.
Effects Of Habitat Quality On Secondary Production In Shallow Estuarine Waters And The Consequences For The Benthic-Pelagic Food Web, David James Gillett
Effects Of Habitat Quality On Secondary Production In Shallow Estuarine Waters And The Consequences For The Benthic-Pelagic Food Web, David James Gillett
Dissertations, Theses, and Masters Projects
Anthropogenic degradation of coastal and estuarine habitats is an ongoing problem facing scientists, natural resource mangers, and the general public. Decreases in habitat quality produce relatively predictable changes in the structure and composition of macrobenthic communities and it has traditionally been assumed that the ecosystem functions of the community change as well. In Chesapeake Bay, the most pervasive cause for the degradation of benthic habitats is the excessive inputs of nutrients that lead to eutrophication and the accumulation of organic matter in the system. Working within this framework, a study was conducted investigating changes in macrobenthic (i.e., secondary) production along …
The Life History Of Longnose Gar, Lepisosteus Osseus, An Apex Predator In The Tidal Waters Of Virginia, Patrick E. Mcgrath
The Life History Of Longnose Gar, Lepisosteus Osseus, An Apex Predator In The Tidal Waters Of Virginia, Patrick E. Mcgrath
Dissertations, Theses, and Masters Projects
Longnose gar (Lepisosteus osseus) inhabit all of the major tributaries of Chesapeake Bay in Virginia, extending from fresh to estuarine waters. Literature concerning longnose gar from tidal environments is limited and this is study concerns important aspects of the life history (e.g., growth, reproduction, dimorphism, movements, and diet). Age, growth, and reproduction are important life history aspects for understanding the biology of fishes and may be affected by the environment in which an individual lives. This study found no differences in the age, growth, and fecundity parameters between longnose gar from tidal portions of Chesapeake Bay tributaries and previous studies …
Alternative Substrates As A Native Oyster (Crassostrea Virginica) Reef Restoration Strategy In Chesapeake Bay, Russell Paul Burke
Alternative Substrates As A Native Oyster (Crassostrea Virginica) Reef Restoration Strategy In Chesapeake Bay, Russell Paul Burke
Dissertations, Theses, and Masters Projects
Oyster shell for native oyster reef restoration is scarce in Chesapeake Bay and other estuaries (Chapter 1). Consequently, alternative substrates merit consideration in oyster restoration. This dissertation examines the suitability of shell alternatives, including granite, concrete, limestone marl, concrete modules and reefballs with reef surveys and experiments in the Rappahannock and Lynnhaven Rivers of Chesapeake Bay. Oyster recruitment, growth, survival, density, biomass, condition, and disease stress, as well as reef accretion and persistence, were measured. In the Lynnhaven River, intertidal riprap had a mean density of 978 oysters m-2 (165 g AFDM m-2) and peak densities > 2000 oysters m-2 (Chapter …
Towards Secure Message Systems, Mengjun Xie
Towards Secure Message Systems, Mengjun Xie
Dissertations, Theses, and Masters Projects
Message systems, which transfer information from sender to recipient via communication networks, are indispensable to our modern society. The enormous user base of message systems and their critical role in information delivery make it the top priority to secure message systems. This dissertation focuses on securing the two most representative and dominant messages systems---e-mail and instant messaging (IM)---from two complementary aspects: defending against unwanted messages and ensuring reliable delivery of wanted messages.;To curtail unwanted messages and protect e-mail and instant messaging users, this dissertation proposes two mechanisms DBSpam and HoneyIM, which can effectively thwart e-mail spam laundering and foil malicious …
Application Of Information Theory And Statistical Learning To Anomaly Detection, Steven Gianvecchio
Application Of Information Theory And Statistical Learning To Anomaly Detection, Steven Gianvecchio
Dissertations, Theses, and Masters Projects
In today's highly networked world, computer intrusions and other attacks area constant threat. The detection of such attacks, especially attacks that are new or previously unknown, is important to secure networks and computers. A major focus of current research efforts in this area is on anomaly detection.;In this dissertation, we explore applications of information theory and statistical learning to anomaly detection. Specifically, we look at two difficult detection problems in network and system security, (1) detecting covert channels, and (2) determining if a user is a human or bot. We link both of these problems to entropy, a measure of …
Comparison Of Full-Wave And Ray-Tracing Analysis Of Mode Conversion In Plasmas, Yanli Xiao
Comparison Of Full-Wave And Ray-Tracing Analysis Of Mode Conversion In Plasmas, Yanli Xiao
Dissertations, Theses, and Masters Projects
This dissertation reports on the first direct comparison between the results of ray-based and full-wave calculations for mode conversion in plasma. This study was motivated by the modular method originally developed by Ye and Kaufman to treat a magnetosonic wave crossing a cold minority-ion gyroresonance layer. We start with the cold plasma fluid model and introduce a system of evolution equations for electrons and two ion species: deuterium and hydrogen. We first study this system of equations for uniform plasma by Fourier methods, which gives the dispersion relations. We discuss how the traditional approach---which eliminates all other dynamical variables in …
Quantum Information Dynamics, Jeffrey Yepez
Quantum Information Dynamics, Jeffrey Yepez
Dissertations, Theses, and Masters Projects
Presented is a study of quantum entanglement from the perspective of the theory of quantum information dynamics. We consider pairwise entanglement and present an analytical development using joint ladder operators, the sum of two single-particle fermionic ladder operators. This approach allows us to write down analytical representations of quantum algorithms and to explore quantum entanglement as it is manifested in a system of qubits.;We present a topological representation of quantum logic that views entangled qubit spacetime histories (or qubit world lines) as a generalized braid, referred to as a super-braid. The crossing of world lines may be either classical or …
Optical Control Of Ultrafast Spin -Wave Relaxation By Magnetic Anisotropy In A Ferromagnet, Kevin James Smith
Optical Control Of Ultrafast Spin -Wave Relaxation By Magnetic Anisotropy In A Ferromagnet, Kevin James Smith
Dissertations, Theses, and Masters Projects
This thesis presents an investigation of the damping of spin waves in ferromagnetic Au(3 nm)/Ni(10 nm)/MgO(001) thin films using the time-resolved Magneto-optical Kerr Effect (TR-MOKE) and ferromagnetic resonance (FMR) techniques. In the optical measurements, a 150 fs, 800 nm laser beam pulse is split into pump and probe components. The pump pulse, containing most of the beam energy, thermally excites coherent spin precession. The weaker probe pulse, time-delayed by a variable beam path, captures the magnetization dynamics via the polar MOKE effect, and oscillations are observed as a function of external field amplitude and direction. The extracted precession frequency is …
Secure And Efficient Data Extraction For Ubiquitous Computing Applications, Chiu Chiang Tan
Secure And Efficient Data Extraction For Ubiquitous Computing Applications, Chiu Chiang Tan
Dissertations, Theses, and Masters Projects
Ubiquitous computing creates a world where computers have blended seamlessly into our physical environment. In this world, a "computer" is no longer a monitor-and-keyboard setup, but everyday objects such as our clothing and furniture. Unlike current computer systems, most ubiquitous computing systems are built using small, embedded devices with limited computational, storage and communication abilities. A common requirement for many ubiquitous computing applications is to utilize the data from these small devices to perform more complex tasks. For critical applications such as healthcare or medical related applications, there is a need to ensure that only authorized users have timely access …