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Ecology Of The Early Life History Of The Caribbean Spiny Lobster, Panulirus Argus: Recruitment, Predation, And Habitat Requirements, Charles A. Acosta

Biological Sciences Theses & Dissertations

Recruitment variability of the early life history stages of marine benthic organisms can have profound consequences on population dynamics. I studied factors affecting recruitment success of postlarvae and early juveniles of the Caribbean spiny lobster. I examined patterns in postlarval supply, investigated wind forcing as a potential transport mechanism for recruiting postlarvae, and quantified predation on postlarvae in south Florida, USA. In an eight-year time series, spiny lobster postlarval supply occurred year-round between the new and first quarter lunar phases. The major annual peak occurred around March corresponding to spawning activity ten months earlier, and a smaller non-seasonal peak occurred …

Active And Passive Settling By Marine Benthic Nematodes, Rodney Duane Bertelsen

Biological Sciences Theses & Dissertations

This study investigates whether active processes participate in the settlement of marine benthic nematodes. The settling rates of three estuarine benthic nematode taxa were examined in a linear flume using two treatments defined by the type of sediment bed placed in the flume. One treatment bed contained sediments rendered "unattractive" by boiling. The other treatment bed contained unaltered "attractive" sediment. Preliminary still water choice experiments confirmed the attractive and unattractive properties of these sediment treatments with each taxon. Recolonization trays placed in the field confirmed that each taxon did disperse in the water column. One taxon (Theristus sp?) exhibited significantly …

Microzooplankton Dynamics In Lower Chesapeake Bay And Its Major Tributaries, Gyung Soo Park

Biological Sciences Theses & Dissertations

This study identified the temporal and spatial variability of microzooplankton density and biomass at 14 stations located within Chesapeake Bay and four rivers. Microzooplankton are defined as those heterotrophic organisms which range from 20 to 200 $\mu$m in size, and in this study were mainly composed of copepod nauplii, rotifers, and ciliates. Ciliates were the most abundant microzooplankton, comprising more than 90% of the total density, with copepod nauplii representing approximately 50% of the total microzooplankton biomass (carbon content). Rotifers contributed less than 5% for both density and biomass of the total microzooplankton.

Maximum ciliate abundance occurred from spring to …

Development Of Solid Phase Microextraction Methods For Contraband Drugs, Vangielynn Cruz Tersol

Chemistry & Biochemistry Theses & Dissertations

The objective of this study is to develop analytical methods for studying contraband drugs at nanogram levels and to demonstrate the utility of the methods. A method which combines solid phase microextraction with ion mobility spectrometry (SPME-IMS) was developed. The SPME-IMS method was used as a rapid screening tool in studying the chemistry of cocaine HCI, heroin HCI, and heroin freebase on surfaces. The total time for sample preparation, reaction, and analysis is approximately seven minutes. Another method that was developed is one that combines solid phase microextraction with gas chromatography (SPME-GC) for the quantitative analysis of cocaine freebase and …

Galaxie, Sarah Ann Livingston

English Theses & Dissertations

This collection of poems primarily features play of language, image, and voice. A postmodern juxtaposition of ancient figures and contemporary ideas, as well as a blurring of the line between autobiography and fiction, revises familiar stories. My goal is to seek what is surprising, daring-a strength of voice combining with a sometimes casual tone which hints towards deeper circumstances. Most specifically, my work exists within a fictional landscape which allows the creation of "a safe space." The gesture of the poem stops everything, commentates on what is suspended and the suspension itself.

Cγ- And Cα-Subunits Provide The Specificity For Camp/Pka Function, Wei Qing Zhang

Theses and Dissertations in Biomedical Sciences

The Cα and Cγ of the cAMP-dependent protein kinase (PKA) are two highly homologous (83% amino acid identity), yet functionally distinct isozymes in vitro for substrate and pseudosubstrate specificity, and in intact cells for cell phenotypes (Beebe, 1992).

To determine the molecular mechanisms underlying the distinct functions in cell phenotypes, in vitro experiments were designed to make a detailed comparison of Cγ and Cα for substrate and pseudosubstrate specificity. To this end, Cγ and Cα were expressed m mammalian cells, bacteria and Sf9 insect cells using baculovirus. Abundant expression of active enzyme was cell system specific. Cγ and Cα expressed …

Influence Of Physics On The Distribution Of Ichthyoplankton Across The Chesapeake Bay Plume, Christian S. Reiss

OES Theses and Dissertations

Most marine fish have retained pelagic larval stages that are spawned away from juvenile habitats. Physical and biological processes on a number of scales may affect larval survival. Mesoscale features like estuarine or riverine plumes and fronts are thought to affect larval survival by transporting larvae to juvenile habitats or by retaining larvae in favorable developmental habitats. It is likely that these features are major contributors in the regulation of shelf-spawned estuarine-dependent taxa.

This study examined how physical oceanographic features affected the spatial distribution of ichthyoplankton across the Chesapeake Bay Plume. Larval surveys were conducted across the shelf and within …

Conditioned Response To Ethanol As Indicated By Spontaneous Motor Activity, Tevfik Alici

Psychology Theses & Dissertations

A group of rats were given 1.6 g/kg intraperitoneal (IP) injections of either saline or ethanol on 16 successive conditioning days (CD's). During each two-day period of the 16-day sequence, the rats received saline on one day in a specifically "saline-paired" environment and ethanol on the next day in an "ethanol-paired" environment. Visual, olfactory, auditory, and tactile manipulations were utilized to create these two different environments. In order to determine the conditioned response to ethanol, rats were given saline in "ethanol-paired" environments at the end of the 16-day sequence. SMA on this day was compared to that of the previous …

The Measurement Of Mood Variation Over Time And Its Relation To Career Decision-Making Self-Efficacy In Young Adolescents, William Thomas Pinkston

Theses and Dissertations in Urban Services - Urban Education

Variation in mood states over time and the relationship between mood states and career decision making self-efficacy in young adolescents were investigated using the Profile of Mood States (POMS), the Multiple Affect Adjective Check List - Revised (MAACL-R), the Rotter's IE locus of control test, and the Career Planning Confidence Scale (CPCS). These tests were administered twice a week for six weeks. A correlational analysis was performed. The results showed a higher correlation between mood state measures as the subjects' moods varied over time than between either mood measure and locus of control which did not covary with either of …

Input Design For Systems Under Identification Using Indirect And Direct Methods, Marco P. Schoen

Mechanical & Aerospace Engineering Theses & Dissertations

The motivation for system identification can be manifold. In this work, the provocation to identify unknown system characteristics is derived from the control engineering point of view. That is, one intends to design a control strategy based on the identified system properties. The used system identification methods are the Open-Loop Kalman filter System Identification method (OKID) and the Closed-Loop System Identification method (CLID). It is shown that the quantitative largest error of the system identification is given by its model representation, that is the attempt to describe a system with model parameters which poses a linear relationship with the input/output …

Laureate, 1997, Old Dominion University

Yearbooks

1997 yearbook of Old Dominion University

Abnormalities In Post-Translational Processing Of Platelet Rap 1b In Niddm: A Possible Cause Of Platelet Hyperactivity And Cardiovascular Disease In Diabetes, Elizabeth Ann Hall

Theses and Dissertations in Biomedical Sciences

Post-translational processing is critical for the appropriate subcellular localization and function of platelet G-proteins. The majority of the platelet responses to agonists are mediated through specific receptor/G-protein complexes. Therefore, G-protein activity is central to "normal" platelet activity (i.e. aggregation). We have shown that Simvastatin, the in vivo inhibitor of HMG CoA Reductase and therefore isoprenoid synthesis, inhibits the post-translational processing of specific platelet G-proteins and alters platelet responses to agonists. These results show the importance of post-translational processing of G-proteins to platelet activity. Altered post-translational processing of specific G-proteins may explain platelet hyperactivity and the increased incidence of cardiovascular disease …

Modeling Plankton Community Structure Under Environmental Forcing On The Southeastern United States Continental Shelf, Andrew Glenn Edward Haskell

OES Theses and Dissertations

A system of coupled ordinary differential equations was developed to investigate the time-dependent behavior of phytoplankton, copepod, and doliolid populations associated with upwelling features on the outer southeastern U.S. continental shelf. Model equations describe the interactions of nitrate, ammonium, two phytoplankton size fractions, five copepod developmental stages, doliolids, and a detrital pool. Model dynamics are based primarily upon data obtained from field and laboratory experiments made for southeastern U.S. continental shelf plankton populations. Numerous simulations were performed to investigate the effects of environmental variability on the temporal distribution of the structure of resident plankton populations. Variations on a reference simulation, …

Distribution Of Free Marine Viruses Of Lower Chesapeake Bay And Their Effects On Life-History Parameters Of The Estuarine Copepod Acartia Tonsa Dana, Lisa A. Drake

OES Theses and Dissertations

Naturally occurring viruses are very abundant in fresh, estuarine, and marine waters, with densities on the order of 10⁵-10⁸ viruses ml^-1. Research has focused on virus effects on bacteria, cyanobacteria, and phytoplankton, as well as mechanisms of virus production and decay. However, little is known about the distribution of viruses in benthic environments or virus effects on organisms in higher trophic levels.

To determine the distribution of virus-like particles (VLPs) and bacteria in the lower Chesapeake Bay, vertical profiles of VLPs and bacteria were determined through the water column and 15-25 cm into the sediment …

Fluxes Of Copper-Complexing Ligands From Estuarine Sediments, Stephen A. Skrabal, John R. Donat, David J. Burdige

OES Faculty Publications

Most studies of the organic complexation of Cu in natural waters have focused on distributions and processes in the water column, where a significant fraction of Cu-complexing ligands may be biologically produced. We present direct evidence for a flux of Cu-complexing ligands from estuarine sediments, demonstrating that sediments are a significant, yet previously unrecognized source of the ligands. Fluxes of Cu-complexing ligands from Chesapeake Bay sediments range from 300 to 1,200 nmol m^-2 d^-1, exceeding fluxes of total dissolved Cu by 3->40-fold, suggesting that any Cu fluxing from the sediments is likely to be organically complexed. …

Yield-Per-Recruit Analysis And Management Strategies For Atlantic Croaker, Micropogonias Undulatus, In The Middle Atlantic Bight, Luiz R. Barbieri, Mark E. Chittenden, Cynthia M. Jones

OES Faculty Publications

The effect of different fishing mortality (F) and natural mortality (M), and age at first capture (t(c)) on yield-per-recruit of Atlantic croaker, Micropogonias undulatus, in the lower Chesapeake Bay and North Carolina were evaluated with the Beverton-Holt model. Independent of the level of M (0.20-0.35) or F (0.01-2.0) used in simulations, yield-per-recruit values for Chesapeake Bay were consistently higher at t((c)) = 1 and decreased continuously with increases in t(c) (2-5). Although maximum yield-per-recruit always occurred at the maximum level off (F=2.0), marginal increases in yield beyond F = 0.50-0.75 were negligible. Current F (F(CUR)) is estimated to be …

Age And Growth Of Larval And Juvenile Atlantic Croaker, Micropogonias Undulatus, From The Middle Atlantic Bight And Estuarine Waters Of Virginia, Stephen W. Nixon, Cynthia M. Jones

OES Faculty Publications

Sagittal otoliths were used to determine age and growth of 605 larval and juvenile Atlantic croaker, Micropogonias undulatus, collected in the Middle Atlantic Bight and estuarine waters of Virginia. This study is the first to use age-based analysis for young Atlantic croaker collected in this region. A Laird-Gompertz model (r2=0.95) was used to describe the growth of Atlantic croaker up to 65 mm standard length (SL) and 142 days (t): SL((t)) = 2.657 exp (4.656 [1-exp (-0.0081t)]); where SL((t)) = standard length at day t. Spatial and temporal patterns in the size and age of Atlantic croaker showed a …

Response Of Otolith Microchemistry To Environmental Variations Experienced By Larval And Juvenile Atlantic Croaker (Micropogonias Undulatus), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana

OES Faculty Publications

Minor and trace elements incorporated into otoliths during growth may permanently record environmental conditions experienced by fishes. To determine the validity of this approach, we used laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to assay sectioned otoliths from juvenile Atlantic croaker (Micropogonias undulatus) collected from each of three sites in the Neuse River, North Carolina, and the Elizabeth River, Virginia. Elemental concentrations at the center of the otoliths did not differ between locations, although both Mg : Ca and Ba : Ca were significantly higher at the edge of otoliths from the Neuse River than from the …

Destruction Of Chloropigments In Copepod Guts, A. B. Bochdansky, D. Deibel

OES Faculty Publications

In a recent account regarding the destruction of chloropigments within the guts of copepods, Head & Harris (1996) (H&H) presented valuable data on pigment destruction in copepods. However, in one of their main conclusions, the authors invoked 2 enzyme pools to explain the pattern of pigment destruction: one directly derived from copepods, the other one produced by the ingested algae. If this conclusion is correct, it would have tremendous impact on the interpretation of data collected by the gut pigment technique. Estimating ingestion rates of copepods in the field would be very difficult, if not impossible, if pigment destruction was …

Detection Of Harmful Algal Blooms Using Photopigments And Absorption Signatures: A Case Study Of The Florida Red Tide Dinoflagellate, Gymnodinium Breve, David F. Millie, Oscar M. Schofield, Gary J. Kirkpatrick, Geir Johnson, Patricia A. Tester, Btyan T. Vintard

OES Faculty Publications

The utility of photopigments and absorption signatures to detect and enumerate the red tide dinoflagellate, Gymnodinium breve, was evaluated in laboratory cultures and in natural assemblages. The carotenoid, gyroxanthindiester, was an adequate biomarker for G. breve biomass; water‐column concentrations corresponded with cell standing crops and chlorophyll a concentrations during bloom events in Sarasota Bay, Florida. Unlike other carotenoids, the relative abundance of gyroxanthin‐diester did not change throughout a range of physiological states in culture and the gyroxanthin‐diester: chlorophyll a ratio exhibited little variability in a natural assemblage during bloom senescence. Stepwise discriminant analysis indicated that wavelengths indicative of in vivo …

Regulation Of Algal Blooms In Antarctic Shelf Waters By The Release Of Iron From Melting Sea Ice, Peter N. Sedwick, Giacomo R. Ditullio

OES Faculty Publications

During summer 1995-96, we measured iron in the water column and conducted iron-enrichment bottle-incubation experiments at a station in the central Ross Sea (76°30'S, 170°40'W), first, in the presence of melting sea ice, and 17 days later, in ice-free conditions. We observed a striking temporal change in mixed-layer dissolved iron concentrations at this station, from 0.72-2.3 nM with sea ice present, to 0.16-0.17 nM in ice-free conditions. These changes were accompanied doubling of algal (diatom) biomass. Our incubation experiments suggest that conditions were iron-replete in the presence of sea ice, and iron-deficient in the absence of sea ice. We surmise …

A Modeling Study Of The Effects Of Size- And Depth-Dependent Predation On Larval Survival, Margaret M. Dekshenieks, Eileen E. Hofmann, John M. Klinck, Eric N. Powell

CCPO Publications

The form of the predation pressure experienced by larval stages of marine invertebrates is largely unknown. However, it is believed that the type, timing and rate of larval predation are critical in determining recruitment to adult populations. In this study, a time and depth-dependent model of the growth and behavior of larvae of the Eastern oyster, Crassostrea virginica, was used to investigate the effects of different forms of size-and depth-dependent predation on larval survivorship. The simulated larval survival for a cohort experiencing size-dependent predation showed that the greatest percent of the cohort survived to competent settlement size when the …

A Study To Determine The Differences In Undergraduate Technology Education Teacher Preparation Curricula In Virginia, Cecil Stanley Burgett

OTS Master's Level Projects & Papers

These goals were analyzed to detect the specific variances among the four technology education certification programs in Virginia: 1. How are the Virginia technology education teacher preparation programs accredited? 2. What is the pedagogical curriculum in undergraduate technology education teacher preparation at each university? 3. What is the technical content of the four Virginia undergraduate technology education teacher preparation programs? 4. What are the field experiences of the four Virginia undergraduate technology education teacher preparation programs? 5. What are the general education requirements of each program?

Drug Prevention Programs Used By Hampton And Newport News School Districts, Charles E. Casey

OTS Master's Level Projects & Papers

Although each school district's drug prevention program operates as a separate entity from the next one, managers might operate their programs more efficiently if information is discovered that could improve them During this study, the researcher would: 1. Identify major differences between the Newport News and the Hampton City Schools Drug Prevention Programs; 2. Determine by comparison if the two drug prevention programs are effective as used or can be improved; 3. Determine if there is a direct correlation between drug usage and a drop in grades; 4. Assess whether each drug prevention program is designed to prevent drug usage …

A Study On The Feasibility Of Implementing Advanced Placement Courses In The Field Of Technology Education, Donald S. Luebbecke, Mark A. Mcgrath

OTS Master's Level Projects & Papers

This study was developed with three goals in mind: 1. To determine the opinions of state supervisors/directors of Technology Education concerning the establishment of an AP program for Technology Education; 2. To request recommendations or nominations for AP credit content areas applicable to Technology Education from state supervisors/directors; 3. To determine the procedures to be followed by the Technology Education profession and The College Board to establish and implement a Technology Education AP program.

A Study To Determine The Demographics And Personal Reasons Students Choose To Take, Robin Marsh Simmons

OTS Master's Level Projects & Papers

The following goals were established to guide the research: 1) Assess the demographics of students choosing to take computer mediated course; 2) Determine the personal reasons students choose virtual classrooms over traditional classrooms.

Problems With The Interpretation Of Mark-Release-Recapture Data In Subterranean Termites (Isoptera: Rhinotermitidae), Anthony D. Curtis, Deborah A. Waller

Biological Sciences Faculty Publications

The Lincoln index (Peterson method) is frequently used to estimate animal population size in mark-release-recapture studies. We tested the accuracy of this method to estimate termite colony size using logs infested with termites that were maintained in the laboratory. Termites were fed paper towels dyed either with 0.05% or 0.1% (w/w) of the dye marker Nile blue and released into their host logs in the laboratory. Following recapture a week later, estimates of termite population size for termites dyed with 0.05% Nile blue, and were approximately 3 times greater for termites dyed with 0.1% Nile blue. Concentrations of 0.1% Nile …

Seasonal Abundance Of Autotrophic Picoplankton In The Pagan River, A Nutrient Enriched Subestuary Of The James River, Virginia, Lillian N. Davis, Karen A. Phillips, Harold G. Marshall

Biological Sciences Faculty Publications

Autotrophic picoplankton had average monthly concentrations of 73.5 X 10⁶ cells/L in the Pagan River, with summer-early fall maxima of 10⁸ cells/L. The abundance peaks increased with rising water temperatures, declining to their least abundance in mid-winter (10⁵ cells/L).

A Quantitative Study Of Diet In Three Species Of Rodents In Natural And Irrigated Savanna Fields, Safianu Rabiu, Robert K. Rose

Biological Sciences Faculty Publications

During July, 1990 - June, 1992 we collected stomach contents of necropsied rodents that totalled 494 Arvicanthis niloticus (Desmarest, 1822), 356 Mastomys natalensis (Smith, 1834) and 273 Tatera valida (Wroughton, 1906) from natural, savanna fields in Nigeria, and 528 Arvicanthis and 367 Mastomys from nearby irrigated fields, where Tatera was never trapped. The materials were processed and microscopically analyzed to determine patterns of diet selection. Sites were sampled for vegetative cover and rodent food resources. More than 90% of the stomach materials could be identified to one of four categories: dicots (vegetative), monocots (vegetative), seeds, and insects. Seeds constituted approximately …

The Drosophila Melanogaster Rad54 Homolog, Dmrad54, Is Involved In The Repair Of Radiation Damage And Recombination, Rolf Kooistra, José B. M. Zonneveld, Anja De Jong, Jan C. J. Eeken, Chris J. Osgood, Jean-Marie Buerstedde, Paul H. M. Lohman, Albert Pastink

Biological Sciences Faculty Publications

The RAD54 gene of Saccharomyces cerevisiae plays a crucial role in recombinational repair of double-strand breaks in DNA. Here the isolation and functional characterization of the RAD54 homolog of the fruit fly Drosophila melanogaster, DmRAD54, are described. The putative Dmrad54 protein displays 46 to 57% identity to its homologs from yeast and mammals. DmRAD54 RNA was detected at all stages of fly development, but an increased level was observed in early embryos and ovarian tissue. To determine the function of DmRAD54, a null mutant was isolated by random mutagenesis. DmRAD54-deficient flies develop normally, but the females …