Digital Commons Network^™

Explosive Vapor Generation And Sampling In Conjunction With Ion Mobility Spectrometry, Saeed H. Almeer

Chemistry & Biochemistry Theses & Dissertations

The primary objective of this research is to develop an inexpensive and reliable method to generate vapor pulses of explosives using 2,4,6-trinitrotoluene TNTl for proof of concept. A secondary objective is to demonstrate the use of the vapor generator in various applications keeping in mind potential field scenarios involving explosives. A vapor generator/collector system was developed which gives reproducible pulses of TNT vapors at nanogram levels. The use of this technology was demonstrated in evaluating different surfaces for vapor adsorption of TNT in conjunction with ion mobility spectrometry as the primary analytical tool. Of the materials examined, Teflon was by …

(A Note On)(2) The Shape Of The Erythrocyte, J. A. Adam

Mathematics & Statistics Faculty Publications

A note on the shape of the red blood cell is revisited, utilizing variational calculus to to find an extremum for the surface area of such a cell, using the volume as a constraint. A fairly significant error in the value of the volume is corrected, and the note concludes with a discussion of measures of cell shape (such as the sphericity index) which are more appropriate than the dimensional surface area to volume ratio.

Effect Of Sampling Errors On Estimates Of Recruitment And Fishing Mortality From Separable Virtual Population Analysis, Emmanis Dorval

Biological Sciences Theses & Dissertations

Separable virtual population analysis (SVPA) models provide estimates of historical recruitment and fishing mortality from analyzing catch data based on the separability of fishing mortality into age specific-gear selection and yearly mortality. These models assume that the catch is randomly sampled and that sampling error is a random variable with constant variance and mean equal to zero. These models do not account for sampling measurement errors that occur when the catch partitioned by age is not measured on every sampling unit without error, and spatio-temporal errors that occur when the observed catch is not representative of the harvested population throughout …

Thin-Layer Prestressed Composite Ferroelectric Driver And Sensor Characterization With Application To Separation Flow Control, Karla M. Mossi

Mechanical & Aerospace Engineering Theses & Dissertations

Experiments were conducted in two different stages--general piezoelectric actuator characterization and flow separation control applications. The characterization of the piezoelectric devices was performed in several stages, due to the many variables that affect performance. The first stage of the characterization consisted of tests conducted on 13 different THUNDER^TM (thin-layer composite unimorph ferroelectric driver and sensor) configurations. These configurations consisted of a combination of 1, 3, 5, 7, and 9 layers of 25μ thick aluminum as backing material, with and without a top layer of 25μ aluminum. All of these configurations used the same piezoelectric ceramic wafer (PZT-5A) with dimensions …

Reaction-Diffusion Models Of Cancer Dispersion, Kim Yvette Ward

Mathematics & Statistics Theses & Dissertations

The phenomenological modeling of the spatial distribution and temporal evolution of one-dimensional models of cancer dispersion are studied. The models discussed pertain primarily to the transition of a tumor from an initial neoplasm to the dormant avascular state, i.e. just prior to the vascular state, whenever that may occur. Initiating the study is the mathematical analysis of a reaction-diffusion model describing the interaction between cancer cells, normal cells and growth inhibitor. The model leads to several predictions, some of which are supported by experimental data and clinical observations $\lbrack25\rbrack$. We will examine the effects of additional terms on these characteristics. …

Pressure-Induced Intracellular Signaling In Isolated Arteries, Victor A. Miriel

Theses and Dissertations in Biomedical Sciences

The ability of cells to respond to mechanical stimuli has been studied through a variety of techniques in numerous cell types. The cells of the vascular wall have adapted to specific mechanical stresses through the activation of intracellular signaling pathways which result in cell-specific responses such as hypertrophy, hyperplasia, proliferation, and migration. Vascular smooth muscle of the arteries have been shown to be sensitive to mechanical stimuli such as stretch, and pressure.

This study attempts to add to the current knowledge of mechanotransduction by utilizing the isolated artery preparation. This preparation allows for the study of vascular smooth muscle signal …

The Role Of Glycoconjugates In Mediating Human Fertilization And Induction Of Fetomaternal Tolerance, Manish S. Patankar

Theses and Dissertations in Biomedical Sciences

Using the hemizona assay (HZA), a in vitro sperm-egg binding assay, we show that specific glycoconjugates known to inhibit immune cell interactions mediated by the selectins, potently block human sperm-egg binding. The selectin ligand sialyl Lewis^x inhibits sperm binding in the HZA by 60% at a concentration of 1 mg/ml. Our data indicates that glycodelin-A, a endometrial glycoprotein known to block sperm-egg binding in the HZA at low concentrations expresses unusual fucosylated lacdiNAc type glycans. The fucosylated lacdiNAc type sugars have been previously shown to be 15-20 fold more potent ligands of E-selectin. Glycodelin-S a seminal plasma glycoform of …

Machiavellianism Achievement And Gender Roles, Kathleen M. Gibson

Psychology Theses & Dissertations

The focus of the current study was to find a relationship between Machiavellianism and achievement motivation. Gender, gender-role orientation, and college major were also introduced as variables. Two-hundred and forty university students majoring in either business or psychology completed various self-report measures. Results based on correlations and an analysis of variance produced the following results: Women of both majors had higher Machiavellian scores than males of both majors; business majors had a higher desire to work hard and were more competitive than psychology majors (especially males); scores on the Machiavellian scale positively correlated with competitiveness for females. For males, Machiavellianism …

Developmental And Hormonal Regulation Of The Expression Of Cytosolic Phospholipase A2 Protein Levels In Baboon Placenta, Kathleen Elizabeth Dunstan

Chemistry & Biochemistry Theses & Dissertations

Cytosolic phospholipase A₂ ( cPLA₂) specifically catalyzes the release of arachidonate from membrane phospholipids, thus initiating synthesis of prostaglandins, thromboxanes, and other eicosanoids. The human and nonhuman primate placenta actively synthesize high levels of eicosanoids which play both an autocrine and paracrine role in placental function. Previous studies in Dr. Miriam D. Rosenthal's laboratory have shown that cPLA₂ mRNA levels are developmentally regulated. The present study was designed to determine whether placental cPLA₂ protein levels increased during gestation. Since the marked increases in estrogen levels during normal pregnancy have been shown to enhance morphological and …

The Influence Of An Early Childhood Program On The Academic Achievement, Attendance, And Attitudes Of Urban At-Risk Students, Daisy Mccray Murphy

Theses and Dissertations in Urban Services - Urban Education

The purpose of this study was to examine the influence of an early childhood preschool program on the achievement, attendance, and attitudes of at-risk students in an urban Southeastern school division in Virginia. The study compared two groups of Title I eligible four-year-olds, those who participated (n = 88) and those who did not non-participate (n = 54), in a preschool program. A review of the literature revealed that early intervention efforts have addressed the school success dilemma for at-risk students with varying degrees of effectiveness. Increased attention toward the implementation of developmentally appropriate learning environments have afforded at-risk students …

Environmental Variability Effects On Marine Fisheries: Four Case Histories, Eileen E. Hofmann, T. M. Powell

CCPO Publications

The changing nature of marine fisheries requires management approaches that recognize and include ecosystem and environmental effects. Therefore, we review some examples of exploited fishery stocks in which environmental control is a major contributor to structuring the abundance and distribution of the stock. Four examples, taken from studies of northern cod (Gadus morhua), cod and haddock (Melanogrammus aeglefinus) larvae, the eastern oyster (Crassostrea virginica), and Antarctic krill (Euphausia superba), are given that clearly illustrate environmental control on the fishery. From these examples, we argue that future management strategies for exploited fisheries must include effects of environmental variability. In particular, management …

Circulation, Vol. 5, No. 2, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Winter 1998 issue of CCPO Circulation featuring article "Coastal Oceanographic Research Experiences in Chile"

Type I Camp-Dependent Protein Kinase Delays Apoptosis In Human Neutrophils At A Site Upstream Of Caspase-3, Lav K. Parvathenani, E. Stephen Buescher, Enrique Chacon-Cruz, Stephen J. Beebe

Bioelectrics Publications

Current data suggest that apoptosis controls neutrophil numbers in tissues. We analyzed roles for and the sites of action for the cAMP-dependent protein kinases (cAPKs) in apoptosis induced in human neutrophils by in vitro storage, cycloheximide (CHX) exposure, and anti-Fas exposure. Treatment with 8-chlorophenylthio-cAMP (8-CPT-cAMP) prolonged the time required for 50% of the cells to exhibit apoptotic morphology (t 50) from 16.3 to 41.8 h (in vitro culture), from 2.4 to 7.8 h (CHX), and from 4.8 to 6.5 h (anti-Fas). CHX ± 8-CPT-cAMP did not significantly alter resting intracellular calcium levels and H-89, a selective inhibitor of cAPK, had …

Ecology Of The Eastern Cottonmouth (Agkistrodon P. Piscivorus) At Back Bay National Wildlife Refuge: A Comparative Study Of Natural And Anthropogenic Marsh Habitats, Chad Lee Cross

Biological Sciences Theses & Dissertations

Mark-recapture sampling and radiotelemetry were used to investigate populations of the eastern cottonmouth, Agkistrodon p. piscivorus, in both natural and anthropogenic marsh habitats at Back Bay National Wildlife Refuge (BBNWR), Virginia Beach, Virginia from autumn 1995 to late spring 1998. Mark-recapture subjects were captured, marked by ventral scale-clipping, and released back into the population. A modified Schnabel Census estimator was used to estimate population sizes and corresponding densities in both marsh systems based on a total of 244 captures of 222 individuals. Most snakes were found >0.05 in from water, but it was apparent that proximity to water played …

Age, Growth, And Mortality Of Black Drum, Pogonias Cromis, In The Chesapeake Bay Region, Cynthia M. Jones, Brian Wells

OES Faculty Publications

We used otolith ageing to describe the population dynamics of black drum, Pogonias cromis, collected over a three-year period from the Chesapeake Bay region's commercial and recreational fisheries. Black drum average age, total length, and weight were 26 years, 109.5 cm, and 22.1 kg respectively. The oldest fish was 59 years and fish older than 50 years were present in the catch from 1990 to 1992. Growth in length slowed by age 20, whereas growth in weight did not slow until age 45. A von Bertalanffy growth function was fitted to our data (L(infinity) = 117.3 cm, …

The Biogeochemical Cycling Of Dissolved Organic Nitrogen In Estuarine Sediments, David J. Burdige, Shilong Zheng

OES Faculty Publications

Benthic fluxes and pore-water profiles of dissolved organic nitrogen and carbon (DON and DOC, respectively) were determined in seasonal studies at contrasting sites in Chesapeake Bay. Pore-water dissolved organic matter (DOM) concentrations were elevated over bottom-water values, generally increased with depth, and ranged from 15 to similar to 160 μM for DON and ~200-2000 μM for DOC. Pore-water DOM concentrations and the C:N ratio of this material showed spatial (depth) and temporal changes that varied among the sites studied. These trends appeared to be related to differences in the types of sediment organic matter (SOM) undergoing remineralization, as well as …

Iron In Ice Cores From Law Dome, East Antarctica: Implications For Past Deposition Of Aerosol Iron, R. Edwards, Peter N. Sedwick, Vin Morgan, C. F. Boutron, S. Hong

OES Faculty Publications

Total-dissolvable iron has been measured in sections of three ice cores from Law Dome, East Antarctica, and the results used to calculate atmospheric iron deposition over this region during the late Holocene and to provide a preliminary est. of aerosol iron deposition during the Last Glacial Maximum (LGM). Ice-core sections dating from 56-2730 BP (late Holocene) and ∼18 000 BP (LGM) were decontaminated using trace-metal clean techniques, and total-dissolvable iron was determined in the acidified meltwaters by flow-injection analysis. Our results suggest that the atmospheric iron flux onto the Law Dome region has varied significantly over time-scales ranging from seasonal …

A Geochemical Study Of Marine Sediments From The Mac. Robertson Shelf, East Antarctica: Initial Results And Palaeoenvironmental Implications, Peter N. Sedwick, P. T. Harris, L. G. Robertson, G. M. Mcmurtry, M. D. Cremer, P. Robinson

OES Faculty Publications

Sediments from the Antarctic continental margin may provide detailed palaeoenvironmental records for Antarctic shelf waters during the late Quaternary. Here we present results from a palaeoenvironmental study of two sediment cores recovered from the continental shelf off Mac. Robertson Land, East Antarctica. These gravity cores were collected approximately 90 km apart from locations on the inner and outer shelf. Both cores are apparently undisturbed sequences of diatom ooze mixed with fine, quartz-rich sand. Core stratigraphies have been established from radiocarbon analyses of bulk organic carbon. Down-core geochemical determinations include the lithogenic components Al and Fe, biogenic components opal and organic …

Trace Element Signatures In Otoliths Record Natal River Of Juvenile American Shad (Alosa Sapidissima), Simon R. Thorrold, Cynthia M. Jones, Steven E. Campana, James W. Mclaren, Joseph W. H. Lam

OES Faculty Publications

The elemental composition of fish otoliths may represent a permanent record of the environmental conditions an individual has experienced as trace elements, incorporated into the growing surface of the otolith, reflect the physical and chemical characteristics of the ambient water. We tested the utility of trace element signatures in otoliths as natural tags of the river of origin of juvenile American shad (Alosa sapidissima) collected from the Connecticut, Hudson and Delaware Rivers in August and October 1994. Four elements (K, Mn, Sr, and Ba) showed significant variability among sites within rivers in August, although only Mg showed a …

Mesozooplankton Distribution And Abundance In The Pagan River: A Nutrient Enriched Subestuary Of The James River, Virginia, Lillian N. Davis, Harold G. Marshall

Biological Sciences Faculty Publications

The mesozooplankton in the Pagan River was dominated by calanoid copepods, with abundance peaks occurring during late winter-early spring and from late summer into early fall. This included spring, summer, and fall abundance maxima. The total mean abundance of the mesozooplankton was 3,008/m³.

Understanding The Success And Failure Of Oyster Populations: The Importance Of Sampled Variables And Sample Timing, Thomas M. Soniat, Eric N. Powell, Eileen E. Hofmann, John M. Klinck

CCPO Publications

One of the primary obstacles to understanding why some oyster populations are successful and others are not is the complex interaction of environmental variables with oyster physiology and with such population variables as the rates of recruitment and juvenile mortality. A numerical model is useful in investigating how population structure originates out of this complexity. We have monitored a suite of environmental conditions over an environmental gradient to document the importance of short time-scale variations in such variables as food supply, turbidity, and salinity. Then, using a coupled oyster disease population dynamics model, we examine the need for short rime-scale …

Seasonal Patterns Of Nitrogen Fixation In Termites, A. D. Curtis, D. A. Waller

Biological Sciences Faculty Publications

Summary

1. Termite nitrogenase activity was highest in autumn and spring (≈ 3 µg N₂ fixed termite fresh mass (g)^–1 day^–1) and lowest in winter and summer (≈ 0·8 µg N₂ fixed termite fresh mass (g)^–1 day^–1).

2. The nitrogenase activity of worker termites was significantly higher than all other castes (1·58 ± 0·27 µg N₂ fixed termite fresh mass (g)^–1 day^–1).

3. Worker termites constituted the largest proportion of all the castes throughout the study period (≈ 90%).

4. The localized input of fixed nitrogen by termites …

Phytoplankton Composition Within The Tidal Freshwater Region Of The James River, Virginia, Harold G. Marshall, Lubomira Burchardt

Biological Sciences Faculty Publications

Based on a 10.5 year data set, 271 taxa were identified at a single tidal freshwater station in the James River. The mean monthly concentrations of major algal categories, total biomass and productivity are given. Diatom maxima were associated with peak periods of river discharge, with chlorophytes, cyanobacteria, and autotrophic picoplankton abundance and productivity greater during reduced river flow and more stable water conditions.

Grandparents Today: A Demographic Profile, Maximiliane E. Szinovacz

Sociology & Criminal Justice Faculty Publications

This article presents a demographic profile of grandparents, using the National Survey of Families and Households. Specific dimensions of grandparenthood addressed include grandparents' survival, the timing of grandparenthood, grandparents' involvement in other roles, surrogate parenting, and stepgrandparents. The data indicate considerable heterogeneity among grandparents of different genders and races or ethnicities. They also suggest modifications in previous descriptions of modern grandparenthood.

Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord Gale, Jerry L. Pitt

Civil & Environmental Engineering Faculty Publications

The toxicity of common compounds of lead, cadmium and zinc was evaluated in waters similar to that found in the world's largest lead producing area in Missouri. Static, acute toxicity tests were performed using fathead minnows (Pimephales promelas) and water fleas (Daphnia magna) respectively. Test organisms were subjected to varying amounts of sulfide, carbonate, chloride and sulfate salts of lead, zinc and cadmium mixed in hard, alkaline waters typical to this region. Median lethal concentrations were calculated using nominal versus measured metal concentrations. Measured metal concentrations included four different metal fractionation (extraction/filtration) techniques at different pH …

Cladistic Analysis Of 37 Mediterranean Bogidiellidae (Amphipoda), Including Bogidiella Arista, New Species, From Turkey, Stefan Koenemann, Ronald Vonk, Frederick R. Schram

Biological Sciences Faculty Publications

A new subterranean amphipod species, Bogidiella (Medigidiella) arista, found in the mesopsam mic ground waters of southern Anatolia, Turkey, is described, together with Bogidiella (Bogidiella) calicali Karaman, the latter being recorded for the first time in the eastern Mediterranean. A cladistic analysis of 37 Mediterranean species of the family Bogidiellidae is performed, using 4 species from the Canary Islands as an outgroup. Alternatively, 2 cladistic software packages, PAUP 3.1.1 and HENNIG86, are employed to calculate consensus trees of minimal length. The resulting trees show more or less identical robust clades, characterizing a central, a central-eastern, …

Creating A Canonical Scientific And Technical Information Classification System For Ncstrl+, Melissa E. Tiffany, Michael L. Nelson

Computer Science Faculty Publications

The purpose of this paper is to describe the new subject classification system for the NCSTRL+ project. NCSTRL+ is a canonical digital library (DL) based on the Networked Computer Science Technical Report Library (NCSTRL). The current NCSTRL+ classification system uses the NASA Scientific and Technical (STI) subject classifications, which has a bias towards the aerospace, aeronautics, and engineering disciplines. Examination of other scientific and technical information classification systems showed similar discipline-centric weaknesses. Traditional, library-oriented classification systems represented all disciplines, but were too generalized to serve the needs of a scientific and technically oriented digital library. Lack of a suitable existing …

Non-Volatile Dissolved Organic Iodine In Marine Water, Xianhao Cheng

OES Theses and Dissertations

An analytical scheme for the determination of marine DOI has been established. The concentration of DOI is estimated as total iodine (TI) minus total inorganic iodine (TII). The concentration of total iodine is determined as [special characters omitted] after DOI has been oxidized to inorganic iodine quantitatively by intensive UV-irradiation and all the inorganic iodine in the samples had been converted to [special characters omitted] by the addition of NaClO.

Production of DOI in seawater can be via both non-phytoplankton and phytoplankton related processes. In the former, iodide is converted to DOI. In the latter, most likely, iodate is converted …

Tidally Driven Residual Circulation In Shallow Estuaries With Lateral Depth Variation, Chunyan Li, James O'Donnell

CCPO Publications

Tidally driven residual circulation in shallow estuaries with lateral depth variation has been studied analytically using a two-dimensional, depth-averaged model. The solution is presented for a v-shaped channel. Exchange flow is found to be correlated with the topography. The magnitude of this exchange flow depends mainly on four parameters: the ratio between the minimum depth on the shoal and the maximum depth in the channel, the ratio between the tidal amplitude at the mouth and the mean depth, the ratio between the length of the estuary and the tidal wave length, and the ratio between the tidal timescale and the …

Vertical Profiles Of Bromoform In Snow, Sea Ice, And Seawater In The Canadian Arctic, William T. Sturges, Glenn F. Cota, Paul T. Buckley

CCPO Publications

Bromoform (CHBr₃) was measured in vertical profiles from the snow surface through the snowpack, sea ice, and water column to the seafloor at Resolute Bay, Canada, in the sprig of 1992. Elevated concentrations of bromoform were observed in both the ice (32-266 ng L^-1 by liquid water volume) and seawater (~ 20 ng L^-1 ) at the ice-water interface, associated with bromoform emission from ice microalgae. A surprising finding was a second horizon of high bromoform concentrations (336-367 ng L^-1) in sea ice at the snow-ice interface. Chlorophyll and salinity were also elevated in …