Digital Commons Network^™

Understanding The Success And Failure Of Oyster Populations: Climatic Cycles And Perkinsus Marinus, Thomas M. Soniat, John M. Klinck, Eric N. Powell, Eileen E. Hofmann

CCPO Publications

Perkinsus (=Dermocystidium) marinus is a major cause of mortality in eastern oysters. Crassostrea virginica. Because initiation of infection and progression of disease are favored by high temperature and high salinity, we hypothesized that climatic cycles influence cycles of disease. Analyses of a 10-y time series of disease prevalence and intensity, chlorophyll a, suspended sediments, water temperature and salinity from a Louisiana site, using a wavelet technique, show a teleconnection between the El Nino-Southern Oscillation (ENSO) and oyster disease in the northern Gulf of Mexico. Salinity increases precede increased disease prevalence by several months. The changes in salinity that trigger changes …

A Comparison Of Global Estimates Of Marine Primary Production From Ocean Color, Mary-Elena Carr, Marjorie A. M. Friedrichs, Marjorie Schmeltz, Maki Noguchi Aita, David Antoine, Kevin R. Arrigo, Ichio Asanuma, Oliver Aumont, Richard Barber, Michael Behrenfeld

CCPO Publications

The third primary production algorithm round robin (PPARR3) compares output from 24 models that estimate depth-integrated primary production from satellite measurements of ocean color, as well as seven general circulation models (GCMs) coupled with ecosystem or biogeochemical models. Here we compare the global primary production fields corresponding to eight months of 1998 and 1999 as estimated from common input fields of photosynthetically-available radiation (PAR), sea-surface temperature (SST), mixed-layer depth, and chlorophyll concentration. We also quantify the sensitivity of the ocean-color-based models to perturbations in their input variables. The pair-wise correlation between ocean-color models was used to cluster them into groups …

Pelagic Functional Group Modeling: Progress, Challenges And Prospects, Raleigh R. Hood, Edward A. Laws, Robert A. Armstrong, Nicholas R. Bates, Christopher W. Brown, Craig A. Carlson, Fei Chai, Scott C. Doney, Paul G. Falkowski, Richard A. Feely, Marjorie A. M. Friedrichs

CCPO Publications

In this paper, we review the state of the art and major challenges in current efforts to incorporate biogeochemical functional groups into models that can be applied on basin-wide and global scales, with an emphasis on models that might ultimately be used to predict how biogeochemical cycles in the ocean will respond to global warming. We define the term "biogeochemical functional group" to refer to groups of organisms that mediate specific chemical reactions in the ocean. Thus, according to this definition, "functional groups" have no phylogenetic meaning-these are composed of many different species with common biogeochemical functions.

Substantial progress has …

Transport Of Antarctic Krill (Euphausia Superba) Across The Scotia Sea. Part Ii: Krill Growth And Survival, Bettina A. Fach, Eileen E. Hofmann, Eugene J. Murphy

CCPO Publications

A time-dependent, size-structured, physiologically based krill growth model was used in conjunction with a circulation model to test the hypothesis that Antarctic krill (Euphausia superba) populations at South Georgia are sustained by import of individuals from upstream regions. Surface phytoplankton concentrations along the simulated drifter trajectories were extracted from historical Coastal Zone Color Scanner (CZCS) measurements and sea ice biota concentrations were calculated from sea ice concentration and extent extracted along drifter trajectories from Special Sensor Microwave/ Imager measurements. As additional food sources, a time series of heterotrophic food was constructed from historical data, and time series of …

Gis And 3d Analysis Applied To Sea Turtle Mortalities And Navigation Channel Dredging, Bradley A. Shellito, Keith B. Lockwood

Virginia Journal of Science

Between 2000 and 2003 there were an increased number of documented sea turtle mortalities related to hopper dredging in the channels of the Chesapeake Bay. A pilot study was undertaken to create a bathymetric surface and three-dimensional model of the Cape Henry Channel using Geographic Information Systems (GIS) as a visualization tool to examine sea turtle mortalities in relation to the dredging. In Fall 2003, the US Army Corps of Engineers dredged the Thimble Shoals Federal Navigation Channel, and a more refined model was developed using this data. This project examines the growing concerns over sea turtle mortality rates and …

Vertical Distribution Of Decapod Larvae In The Entrance Of An Equatorward Facing Bay Of Central Chile: Implications For Transport, Beatriz Yannicelli, Leonardo R. Castro, Arnoldo Valle-Levinson, Larry Atkinson, Dante Figueroa

CCPO Publications

Two short biophysical surveys were carried out in order to assess how the decapod crustacean larvae vertical distribution and circulation patterns in an equatorward facing embayment (Gulf of Arauco, 37° S; 73° W) influenced larval transport into and out of the Gulf. The embayment is located at the upwelling area of south central Chile and features a deep (60 m) and a shallow (25 m) pathway of communication with the adjacent coastal ocean. Profiles of zooplankton, temperature, salinity, dissolved oxygen and current velocity were measured during a 22-h period at the shallow entrance to the gulf. In addition, three zooplankton …

A Fast Parallelized Computational Approach Based On Sparse Lu Factorization For Predictions Of Spatial And Time-Dependent Currents And Voltages In Full-Body Biomodels, Ashutosh Mishra, Ravindra P. Joshi, Karl H. Schoenbach, C. D. Clark Iii

Electrical & Computer Engineering Faculty Publications

Realistic and accurate numerical simulations of electrostimulation of tissues and full-body biomodels have been developed and implemented. Typically, whole-body systems are very complex and consist of a multitude of tissues, organs, and subcomponents with diverse properties. From an electrical standpoint, these can be characterized in terms of separate conductivities and permittivities. Accuracy demands good spatial resolution; thus, the overall tissue/animal models need to be discretized into a fine-grained mesh. This can lead to a large number of grid points (especially for a three-dimensional entity) and can place prohibitive requirements of memory storage and execution times on computing machines. Here, the …

2006 Best Student Paper Awards

Virginia Journal of Science

The recipients of the 2006 Best Student Paper Awards are listed, Virginia Academy of Sciences.

Vehicular Based Drug Box Temperature Control Study, Jonora Mejia

OTS Master's Level Projects & Papers

The following hypothesis was used as the basis of this study: 1. Temperatures of the prehospital drug boxes will remain in an acceptable range when stored in a compartment insulated with rigid, solid foam.

Bogidiella Indica, A New Species Of Subterranean Amphipod Crustacean (Bogidiellidae) From Wells In Southeastern India, With Remarks On The Biogeographic Importance Of Recently Discovered Bogidiellids On The Indian Subcontinent, John R. Holsinger, Y. Ranga Reddy, Mohammed Messouli

Biological Sciences Faculty Publications

Bogidiella indica, new species, is described from three water wells in southeastern India, including a bore-well on the campus of Acharya Nagarjuna University in Nagarjunanagar, a water well in Guntur town, and an agricultural well in the Godavari and Krishna Basin, all in the state of Andhra Pradesh, India. The new species is assigned to the genus Bogidiella Hertzog and to a newly designated species group within the genus. Despite the near circum-global distribution of the family Bogidiellidae, only a single, partially intact specimen of a bogidiellid had been collected from the Indian subcontinent prior to the discovery of specimens …

Open-Ocean Carbon Monoxide Photoproduction, Aron Stubbins, Günther Uher, Cliff S. Law, Kenneth Mopper, Carol Robinson, Robert C. Upstill-Goddard

Chemistry & Biochemistry Faculty Publications

Sunlight-initiated photolysis of chromophoric dissolved organic matter (CDOM) is the dominant source of carbon monoxide (CO) in the open-ocean. A modelling study was conducted to constrain this source. Spectral solar irradiance was obtained from two models (GCSOLAR and SMARTS2). Water-column CDOM and total light absorption were modelled using spectra collected along a Meridional transect of the Atlantic ocean using a 200-cm pathlength liquid waveguide UV-visible spectrophotometer. Apparent quantum yields for the production of CO (AQY_CO) from CDOM were obtained from a parameterisation describing the relationship between CDOM light absorption coefficient and AQY_CO and the CDOM spectra collected. …

Effects Of Salinity Changes On The Photodegradation And Ultraviolet-Visible Absorbance Of Terrestrial Dissolved Organic Matter, E. C. Minor, J. Pothen, B. J. Dalzell, H. Abdulla, K. Mopper

Chemistry & Biochemistry Faculty Publications

We performed laboratory studies to determine the effects of salinity on the photodegradation of dissolved organic matter (DOM) from the Great Dismal Swamp, Virginia, an important source of terrestrial DOM to the lower Chesapeake Bay. Samples were created by mixing Great Dismal Swamp water (ionic strength approximate to 0 mol L^-1) with modified artificial seawater solutions of differing salinities while keeping the final dissolved organic carbon (DOC) concentration constant. These samples were then irradiated for 24 h in a light box providing ultraviolet (UV) light similar to that of natural sunlight. Light absorbance and DOC concentrations decreased after …

2-Aminoethoxydiphenyl Borate As A Prototype Drug For A Group Of Structurally Related Calcium Channel Blockers In Human Platelets, Yuliya Dobrydneva, Christopher J. Abelt, Beth Dovel, Celina M. Thadigiri, Roy L. Williams, Peter F. Blackmore

Chemistry & Biochemistry Faculty Publications

We have synthesized a series of 2-aminoethoxydiphenyl borate (2-APB, 2,2-diphenyl-1,3,2-oxazaborolidine) analogs and tested their ability to inhibit thrombin-induced Ca²⁺ influx in human platelets. The analogs were either synthesized by adding various substituents to the oxazaborolidine ring (methyl, dimethyl, tert-butyl, phenyl, methyl phenyl, and pyridyl) or increasing the size of the oxazaborolidine ring to seven- and nine-membered rings. NMR analysis of the boron-containing analogs suggests that each of them exist as a ring structure through the formation of an N -> B coordinate bond (except for the hexyl analog). The possibility that these boron-containing compounds formed dimers was also …

Improving Group Work: Voices Of Students, Brian K. Payne, Elizabeth Monk-Turner, Donald Smith, Melvina Sumter

Sociology & Criminal Justice Faculty Publications

Group work is increasingly being used in a variety of college courses. A number of strengths have driven the increase in the use of this form of collaborative learning. Still, a number of problems potentially limit the use of group projects. In this study, we report on research in which we examined how students recommended changing group projects. Results are categorized into student-centered themes and faculty-centered themes. Implications are provided.

Oral Cancer Prevalence In Virginia, Karin C. Loftin, Michele Darby, Stacey Plichta, Sophie Thompson, Shreeram Kumar, Louis Abbey

Dental Hygiene Faculty Publications

Purpose. Oral and pharyngeal cancer affects 30,000 Americans a year and kills one fourth of those diagnosed. The primary risk factors for oral cancer are past or present cigarette and tobacco usage, and alcohol consumption in conjunction with tobacco use. Even though the prevalence of oral cancer is relatively low in the younger age groups, this group is most likely to benefit from intervention programs designed to change risky behavior such as smoking, and to prevent oral cancer in the later years. The goal of the study was to identify high-risk target areas for an oral cancer prevention program in …

Distribution And Status Of The Southern Bog Lemming, Synaptomys Cooperi, In Southeastern Virginia, Robert K. Rose

Virginia Journal of Science

The Dismal Swamp subspecies of the Southern bog lemming, Synaptomys cooperi helaletes, was named based on specimens collected during the 1895-1898 biological surveys conducted in the Dismal Swamp by the US Department of Agriculture. Unknown in the 20th Century until re-discovered in 1980, this small boreal rodent was believed to be restricted to the Great Dismal Swamp of Virginia and North Carolina where the cool damp conditions had permitted it to survive during the Holocene. However, field studies conducted since 1980 have revealed southern bog lemmings to be widespread throughout southeastern Virginia, with populations encompassing an area of more …

Geeks At Play: Doing Masculinity In An Online Gaming Site, Natasha Chen Christensen

Reconstruction: Studies in Contemporary Culture

This paper uses data taken from chat logs within a first person shooter game, Quake Online, in order to explore the performance of gender online. Previous research has shown how physicality is given a position of importance in institutions where masculinity is developed and reproduced such as sports and war; cyberspace offers the opportunity of divorcing the performance of masculinity from the body. Researchers of gender in cyberspace are divided into two perspectives about the effect of the absence of a physical body on the performance of gender: One camp believes that without the constraints of the body, gender in …

Imagined Cities, Real Futures: Simcity And The Co-Production Of Urban Dystopias, Samuel Gerald Collins

Reconstruction: Studies in Contemporary Culture

While the author of this chapter agrees with anthropologists who reject an urban studies predicated on postmodern surfaces and insist that we analyze cities in regional, national and global contexts of political economy, he nevertheless suggests that the urban imaginary has never been so important: Movies, television and music have proven all too useful in the continued vilification of an urban underclass. In 2001, in order to explore the role media might play in the structuring and delimitating of the ways we think about cities, Collins assigned SimCity, a computer simulation game combining models of urban development with cellular automata, …

Allegorical Reductions And Social Reconstructions: An Introduction To Games, Gamers, And Gaming Cultures, Matthew Wolf-Meyer, Davin Heckman

Reconstruction: Studies in Contemporary Culture

[First paragraph]

Games have become a central metaphor in representations of society, and most people are familiar enough with Lewis Carroll's Alice to know that when she passes through the looking glass she finds herself embroiled in a game a Chess which is also much more (Carroll 1992 [1897]). This strange game of Chess is simultaneously a simulation and an enactment of social life in Wonderland, and Carroll plots out Alice 's narrative path as a series of tactical Chess moves, which can be understood as both an attempt to win the game and to navigate through Wonderland and her …

When A Killer Body Isn’T Enough: Cross-Gender Identification In Action-Adventure Video Games, Marc Ouellette

Reconstruction: Studies in Contemporary Culture

While sports games try to recreate the atmosphere of a stadium or of television broadcasts of games, role-playing and action-adventure games attempt to duplicate cinematography through animation. For Tomb Raider, the virtual reality created by the cinematic animation of the game produces an environment for male-to-female cross-gender identification, a topic that has received little critical attention. The sense of identification intended in this chapter comes from psychoanalysts Jean Laplanche and Jean-Baptiste Pontalis, who describe identification as a psychological process in which a subject assimilates an aspect, a property, a characteristic of another and transforms himself [or herself] totally or partially …

Angela Johnson: Award-Winning Novels And The Search For Self, Kaavonia M. Hinton-Johnson, Angela Johnson

Teaching & Learning Faculty Publications

It was over a decade ago when Rudine Sims Bishop (1992) prophetically dubbed Angela Johnson as possibly one of "the most prominent AfricanAmerican literary artists of the next generation" (616). At the time she had four picture books to her credit, but the following year she would publish her debut young adult novel, Toning the Sweep. From there, a number of other award-winners would follow and the total of young adult books would increase to eleven and counting. To date, Johnson has three Coretta Scott King Awards, a Michael L. Printz award, and the "Genius Grant" on her list of …

Body Matters In Massively Multiplayer Online Role-Playing Games, C. Jason Smith

Reconstruction: Studies in Contemporary Culture

The virtual body is already here. Though not as “seamless” as the virtual body envisioned in cyberpunk literature and made popular in films like The Lawnmower Man (1992), hundreds of thousands of people in over 114 countries (“Visitor Center”) daily log into massively multiplayer online role-playing games like Everquest, Ultima Online, Anarchy Online, and Earth and Beyond. These massively multi-player online role-playing games (MMORPGs or MMOs for short) [1] combine the extensive rule systems of traditional role-playing games (or RPGs) such as Advanced Dungeons & Dragons with computer graphic technology and online chat. In these computer …

Predictors Of Paternal Involvement In Childcare In Dual-Earner Families With Young Children, Julie N. Jacobs, Michelle L. Kelley

Psychology Faculty Publications

Dual-earner parents (N = 119) of preschool children enrolled in licensed childcare centers completed anonymous questionnaires that examined work and family variables as related to paternal involvement in three areas: engagement (i.e., one-on-one interaction with the child), responsibility (i.e., taking care of the child’s needs), and accessibility (i.e., being available to the child without directly interacting). Paternal responsibility was predicted by beliefs about fathering and structural variables (e.g., hours fathers and mothers worked). The percentage of time fathers spent as their child’s primary caregiver was predicted by structural variables (e.g., mothers’ work hours) and belief variables (e.g., men’s beliefs about …

Rf-Generated Ambient-Afterglow Plasma, Shariff Shakir, Bijan Pashaie, Shirshak K. Dhali

Electrical & Computer Engineering Faculty Publications

Atmospheric pressure plasmas have gained importance due to their potential application in polymer surface treatment, surface cleaning of metals, thin film deposition, and destruction of biological hazards. In this paper a radio-frequency driven atmospheric pressure afterglow plasma source in argon and helium is discussed. The light intensity measurement shows that the radio-frequency discharge is continuous in time unlike the intermittent nature of a low frequency dielectric-barrier discharge. The discharge, under ambient conditions, can be generated in argon, helium, and nitrogen. Spectroscopic measurements show that metastables are capable of producing oxygen atoms and other excited species. The argon afterglow, in particular, …

Dynamics Of An Atmospheric Pressure Plasma Plume Generated By Submicrosecond Voltage Pulses, Xinpei Lu, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

Nonequilibrium plasmas driven by submicrosecond high voltage pulses have been proven to produce high-energy electrons, which in turn lead to enhanced ionization and excitations. Here, we describe a device capable of launching a cold plasma plume in the surrounding air. This device, "the plasma pencil," is driven by few hundred nanosecond wide pulses at repetition rates of a few kilohertz. Correlation between current-voltage characteristics and fast photography shows that the plasma plume is in fact a small bulletlike volume of plasma traveling at unusually high velocities. A model based on photoionization is used to explain the propagation kinetics of the …

Tick Pheromones And Their Use In Tick Control, Daniel E. Sonenshine

Biological Sciences Faculty Publications

Tick pheromones that regulate assembly, attraction/aggregation/attachment, and mating behavior have been described. Most of the compounds regulating these behaviors are purines, substituted phenols, or cholesteryl esters. Other pheromonal compounds include organic acids, hematin, or ecdysteroids. Novel devices have been developed that combine the specific compounds comprising these pheromones with an acaricide. When applied to tick-infested vegetation or directly to the body surfaces of livestock or companion animals, these devices are effective for tick control. This review summarizes the current state of knowledge of tick pheromones. In addition, this review also presents examples illustrating how devices using tick pheromones can offer …

The Adaptive Value Of Aggregation Among Juvenile Caribbean Spiny Lobster: An Evaluation Using Individual-Based Modeling, Thomas W. Dolan Iii, Mark J. Butler Iv

Biological Sciences Faculty Publications

Ontogenetic changes in gregariousness by pre-reproductive animals, like that observed in juvenile Caribbean spiny lobsters (Panulirus argus), may be adaptive and reflect size-specific changes in the effectiveness of aggregation in promoting survival. Alternatively, aggregation may simply result from changes in the distribution or availability of suitable habitat structure, or from other behaviors that enhance survival. There are currently two hypotheses explaining the potential benefits of gregarious behavior in juvenile spiny lobsters, both of which focus on increasing survivorship by reducing predation pressure: the group benefit hypothesis and the guide hypothesis. The group benefit hypothesis argues that aggregations of …

An Examination Of Differences Between Occupational-Technical Student And Transfer Student Engagement At Small Community Colleges In Virginia, Janet T. Laughlin

Educational Leadership & Workforce Development Theses & Dissertations

This study examined the differences in levels of student engagement between occupational-technical students and transfer students in an attempt to gain insight into why so many students fail to attain their educational goals. Students' engagement or involvement with their educational institution and program of study is considered a major contributor to persistence and graduation. Research on student engagement as it relates to persisters and leavers includes the five student engagement variables benchmarked by the Community College Survey of Student Engagement (CCSSE): (a) active and collaborative learning, (b) student effort, (c) academic challenge, (d) student-faculty interaction, and (e) support for learners. …

Structure-Function Studies Of The Camp-Dependent Protein Kinase In Vitro And In Intact Cells, Gary Z. Morris

Theses and Dissertations in Biomedical Sciences

There are 518 protein kinase genes in the human genome; this constitutes about 1.7% of all human genes. The cAMP-dependent protein kinase (PKA) serves as the prototypic model for the study of kinases because it contains a conserved catalytic core shared with all eukaryotic kinases, it is the simplest kinase, and it is one of the best-characterized serine/threonine kinases. PKA is ubiquitous in mammals and regulates multiple physiological mechanisms such as the cell cycle, apoptosis, cell motility, energy metabolism, and gene transcription through a well-defined intracellular signaling pathway. While PKA clearly has a central physiological role it is still unclear …

Development Of Single Nanoparticle Optical Assays For Imaging Single Living Cells, William John Brownlow

Chemistry & Biochemistry Theses & Dissertations

Multi-drug resistance (MDR) has been reported in both prokaryotes and eukaryotes; the pathogenic gram-negative bacteria Pseudomonas aeruginosa can extrude a variety of structurally and functionally diverse substrates via a number of membrane transport systems leading to MDR. We have developed a novel nanoparticle assay to characterize both the membrane transport system composed of the MexAB-OprM efflux pump and the membrane permeability induced by antibiotics. Gold (Au) and silver (Ag) nanoparticles were investigated for use as probes to explore membrane transport in P. aeruginosa.

The surface plasmon absorption (color) of Au nanoparticle solutions was found to change in the presence …