Digital Commons Network^™

On The Unique Tree Representation Of Graphs, Beverly Jamison

Computer Science Theses & Dissertations

This dissertation investigates classes of graphs which admit tree representations unique up to isomorphism. The definitions of these classes are based on local properties of P₄'s, A template structure theorem is given which illustrates the nature of the local properties. The template theorem is instantiated for three different classes of graphs. Properties specific to each of the classes are used to produce a tree representation which can be used for graph computations, such as efficient resolution of graph isomorphism. Linear time algorithms for the recognition of three classes of graphs and for the construction of their tree representations …

The Remipedia (Crustacea): A Study Of Their Reproduction And Ecology, Jill Yager

Biological Sciences Theses & Dissertations

Remipedes are an unusual group of troglobitic crustaceans that live exclusively in anchialine caves. Since their discovery in 1979, nine species have been described, seven of which are found in caves in the West Indies, one from the Yucatan peninsula of Mexico and one from the Canary Islands. Most of what is known about these animals has come mainly from taxonomic descriptions. Little has been published about their reproductive biology or ecology. The objectives of this dissertation were to investigate the reproductive biology and ecology of the remipedes inhabiting Sagittarius Cave on Grand Bahama Island, Bahamas.

Sagittarius Cave was chosen …

Microwell Based Competitive Enzyme Immunoassay For Quantifying Serum Triiodothyronine And Thyroxine Levels, Yiwen Yang

Chemistry & Biochemistry Theses & Dissertations

A microwell based competitive enzyme immunoassay for determination of total thyroxine and triiodothyronine in human serum was developed with use of horseradish peroxidase conjugate. The assay, which can be performed in only 1.5 hours at room temperature, involves simultaneous incubation of T₃- or T₄- HRPO conjugate and serum sample in anti-T₃ or anti-T₄ gamma globulin fraction coated polystyrene microwells.

Isolation of anti-T₃ and anti-T₄ gamma globulin fractions were accomplished from whole antiserum by using DEAE-cellulose chromatograph. A carbodiimide coupling method was described to prepare the T₄- and T₃-HRPO …

Mathematical Models Of Prevascular Tumor Growth By Diffusion, Sophia A. Maggelakis

Mathematics & Statistics Theses & Dissertations

A study of several complementary mathematical models that describe the early, prevascular stages of solid tumor growth by diffusion under various simplifying assumptions is presented. The advantage of these models is that their degree of complexity is relatively low, which ensures fairly straightforward comparisons with experimental or clinical data (as it becomes available), yet they are mathematically sophisticated enough to capture the main biological phenomena of interest.

The tumor growth and cell proliferation rate are assumed to depend on the local concentrations of nutrients and inhibitory factors. The effects of geometry and spatially non-uniform inhibitor production and non-uniform nutrient consumption …

A Comparison Of The Academic Achievement Of Urban Second-Grade Pupils With Different Forms Of Public Preschool Experience, Elva Williams Hunt

Theses and Dissertations in Urban Services - Urban Education

Assessment of the potential value of the preschool experience has prompted urban educators to consider the advantages of preschool service delivery by the public schools. Urban policy makers ponder whether or not advocacy for preschool education should include advocacy of the provider. This study addressed the provision of preschool service for students from urban low-income families.

The grade placement of students born in three consecutive years was observed to determine their progress during the first three years of public schooling. Students were categorized with regard to their participation in preschool: some had attended a public school system preschool, First Step; …

The Temporal And Spatial Distribution Of Blue Crab Larvae On The Mid-Atlantic Bight Adjacent To The Chesapeake Bay, 1982-1983, Lyle Michael Varnell

OES Theses and Dissertations

Recruitment processes are important information for the management of commercially and recreationally exploited marine species. Recruitment processes of the Chesapeake Bay's most important commercial and recreational species, the blue crab, are unknown, due in part to the lack of knowledge of the processes directly preceeding recruitment.

The present study was undertaken to investigate and explain the movement and developmental patterns of blue crab larvae while offshore. Interannual and intraseasonal variations of these patterns were also examined.

Sampling occurred from May to November during 1982 and 1983. Larvae were collected at three depths (neuston layer (upper 10 cm), one meter and …

Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth

OES Theses and Dissertations

The biomass distribution of the three main size components of the phytoplankton (net, nano, and picoplankton) was examined in the lower Chesapeake Bay. Work was done at two stations during the spring and neap tidal cycles when freshwater flow into the bay was at its seasonal minimum and maximum. Emphasis was placed on how the picoplankton ( < 2.0 μm, > 0.2 μm) reacted during the sampling period.

Picoplankton made up approximately 13% of the total biomass, during the observed time period, at the more oceanic station. The picoplankton fraction contributed up to 16% of the total biomass at the estuarine station. From this …

Explicit And Implicit Calculations Of Turbulent Cavity Flows With And Without Yaw Angle, Guan-Wei Yen

Mechanical & Aerospace Engineering Theses & Dissertations

Computations have been performed to simulate turbulent supersonic flows past three-dimensional deep cavities with and without yaw. Simulation of these self-sustained oscillatory flows have been generated through time accurate solutions of the Reynolds averaged complete Navier-Stokes equations using two different schemes: (1) MacCormack, finite-difference, (2) implicit, upwind, finite-volume schemes. The second scheme, which is approximately 30% faster, is found to produce better time accurate results. The Reynolds stresses have been modeled, using the Baldwin-Lomax algebraic turbulence model with certain modifications. The computational results include instantaneous and time averaged flow properties everywhere in the computational domain. Time series analyses have been …

Self-Concept And Its Relationship To Achievement In Minority Preschool Children, Larry Lennard Lindsey

Psychology Theses & Dissertations

The purpose of the present study was to examine the relationship between self-concept, self-esteem, demographic information, and racial preference to achievement in minority preschool children. The subjects were 56 minority preschool students from a Head Start program in Newport News, Virginia. The subjects were assessed using four different instruments. The instruments were the Joseph Preschool & Primary Self- Concept Screening Test (JPPSST), the Behavioral Academic Self-Esteem Test (BASE), the Preschool Racial Attitudes Measure (PRAM), and the Woodcock-Johnson Psycho-Educational Battery. The JPPSST, PRAM, and Woodcock-Johnson were administered to the subjects by an examiner. The Woodcock-Johnson assessed achievement in two separate areas: …

A Comparative Analysis Of Selected Adolescent Fears, Martina Griffith Meyer

Psychology Theses & Dissertations

The subject of adolescent fears troubling today's generation was studied with the question of specific fears and methods of questioning. It was hypothesized that direct, close-ended questions related to the fear of nuclear war and the fear of failure would elicit responses of greater fear than would indirect, open-ended questions about the future. It was also hypothesized that there would be sex differences in fearfulness of nuclear war with females indicating more fear. It was also expected that there would be developmental differences with 8th-grade subjects more fearful of nuclear war than 12th-grade subjects, and with the older subjects more …

Essays For Undergraduate Liberal Arts Education, Hugo G. Walter

Institute for the Humanities Theses

The purpose of this creative project is to develop an anthology of significant essays for undergraduate liberal arts education. Each essay is preceded by an introduction about the author and the importance of his work. Each essay will encourage the student to think actively and consistently about ideas and issues and to develop a greater sensitivity for and understanding of the world around him.

I have chosen the following twenty-five authors from the nineteenth and twentieth century for this anthology: Henry Thoreau, Henry Adams, Mark Twain, John Stuart Mill, Leo Tolstoy, Friedrich Nietzsche, Susan Anthony, William James, Bertrand Russell, Jane …

Person Perception As A Function Of Sex And Age, Leslie Borland

Psychology Theses & Dissertations

This experiment was designed to explore the effects of sex and age on impressions. The 228 volunteers ranged in age from 18 to 87 years. Subjects were asked to report impressions, using the PPQ, about fictitious targets who were systematically varied according to sex and age. A 2 (Sex of Subject) x 3 (Age of Subject) x 2 (set of Target) x 2 (Age of Target) ANOVA was performed on ratings of likability, adjustment, femininity, masculinity, and androgyny. Older subjects received and gave the highest ratings. Middle-aged subjects gave lower ratings to all targets, but discriminated least. Young subjects were …

Virginia Woolf's Keen Sensitivity To War: Its Roots And Its Impact On Her Fiction, Jane Hamovit Lauter

English Theses & Dissertations

Virginia Woolf saw the nightmare of war as a form of madness which posed a threat not only to individual human life, but to art and culture as well. Her many tragic personal experiences with death together with the fact that she lived through World War I and the beginning of World War II, caused in her a keen sensitivity to the transitory nature of life. Because Woolf saw militarism and the violence of war as blindly chauvinistic and utterly wasteful, war became for her a source of anger and contempt as well as fear.

Woolf's response to war had …

The Composition And Concentrations Of Cyanobacteria In The North Landing River, Virginia And Upper Currituck Sound, North Carolina, Sonja E. Midgette

Biological Sciences Theses & Dissertations

A 12 month study of cyanobacteria composition and concentrations in the North Landing River and upper Currituck Sound was conducted from March 1986 to February 1987. Epifluorescence microscopy and the fluorochrome proflavin were used to determine cell concentrations and vertical, station to station and seasonal distribution of these cells. Cyanobacterial assemblage patterns were coupled with pH, temperature, salinity and water transparency readings.

Cyanobacteria were found to be a persistent and prolific phytoplankton component of both the river and upper sound. For a comparison of vertical distribution for each station, an analysis of variance for. two groups of equal size was …

Best Approximation With Geometric Constraints, Yuesheng Xu

Mathematics & Statistics Theses & Dissertations

This is a study of best approximation with certain geometric constraints. Two major problem areas are considered: best L_p approximation to a function in L_p (0,1) by convex functions, (m, n)-convex functions, (m, n)-convex functions and (m, n)-convex splines, for 1 < p < ∞ , and best uniform approximation to a continuous function by convex functions, quasi-convex functions and piecewise monotone functions.

Spatiality In Ulysses And Cubism, Lingchei Chen

English Theses & Dissertations

The paper is a study of James Joyce's Ulysses and Cubism in modern art. Both forms, as the paper presents, use similar techniques to establish multidimensionality in the work of art. In a spatial novel like Ulysses, because of its techniques, the reader is allowed to experience exactly what the characters experience as Joyce presents every aspect of the Dublin life simultaneously. A Cubist painting does the same. As the Cubist painter captures every side of the object and simultaneously presents these different views on the canvas, the spectator is therefore able to apprehend the object from every possible angle, …

Evaluation Of Equilibrium Turbulence For A Hypersonic Boundary Layer At Nonadiabatic Wall Conditions, Cindy W. Albertson

Mechanical & Aerospace Engineering Theses & Dissertations

This paper presents an experimental study to characterize the compressible turbulent boundary layer produced along a flat plate in the NASA Langley 8-Foot High Temperature Tunnel and determine the test conditions necessary to achieve equilibrium turbulence. In addition, the present study extends the data base for equilibrium compressible turbulent boundary layers over quasi-isothermal walls which are far from the adiabatic wall temperature. The measurements consist of pilot pressure, static pressure, and total temperature distributions in the boundary layer. A flat plate measuring 9.7 feet long and 4.3, feet wide was used for the study to provide a naturally turbulent boundary …

The Geomorphology And Surficial Geology Of The West Flank Of The Blue Ridge, Sherando Area, Virginia, Derek Weston Ryter

OES Theses and Dissertations

The west flank of the Blue Ridge near Sherando, Virginia (Augusta County) consists of many landforms including talus slopes, bedrock cliffs, boulder streams, colluvial slopes, residual knobs, and debris fans. The purpose of this study is to describe the geomorphic history of the area by understanding the spatial and temporal relationships between landforms on the hillslopes.

Boulder streams (maximum 30 m wide, 400 m long, 6.1 m thick) exhibit a gently dipping imbricated fabric and basal shear stresses of 0.1 to 0.4 bars.

Debris fans in Group L (lower) and Group U (upper) are distinguished by topographic position, degree of …

Determinations Of Molecular Weight And Molecular Weight Distribution Of High Polymers By The Rheological Properties, Joan Y. Z. Huang

Mechanical & Aerospace Engineering Theses & Dissertations

Several methods are reviewed by which the molecular weight (MW) and molecular weight distribution (MWD) of polymeric material were determined from the rheological properties. A poly (arylene ether) polymer with six different molecular weights was used in this investigation. Experimentally measured MW and MWD were conducted by GPC/LALLS (Gel Permeation Chromatography/Low Angle Laser Light Scattering), and the rheological properties of the melts were measured by a Rheometric System Four rheometer. It was found that qualitative information of the MW and MWD of these polymers could be derived from the viscoelastic properties, with the methods proposed by Zeichner and Pate1, and …

Investigating The Method Of Structural Topological Variations For Sensitivity Analysis And Design Optimization, Niki A. Mehta

Mechanical & Aerospace Engineering Theses & Dissertations

The method of structural topological variations is a newly developed technique for analysis of frame structures. It provides a novel method that completely avoids formulating and solving simultaneous equations, required in the finite element displacement method. The principal objective of this thesis is to investigate the method of topological variations as a possible design tool and study its applicability in the sensitivity analysis and in the process of design optimization.

A computer code was developed for this method to obtain its comparative performance against the finite element displacement method. For analysis of large structures involving frequent local modifications, the method …

Global/Local Stress Analysis Of Composite Structures, Jonathan B. Ransom

Mechanical & Aerospace Engineering Theses & Dissertations

A method for performing a global/local stress analysis is described and its capabilities are demonstrated. The method employs spline interpolation functions which satisfy the linear plate bending equation to determine displacements and rotations from a global model which are used as "boundary conditions" for the local model. Then, the local model is analyzed independent of the global model of the structure. This approach can be used to determine local, detailed stress states for specific structural regions using independent, refined local models which exploit information from less-refined global models. The method presented is not restricted to having a priori knowledge of …

Mounting Sex Pheromone: A Novel Pheromone Responsible For Mate Recognition In The Ixodidae, Jgc Hamilton

Theses and Dissertations in Biomedical Sciences

Cholesterol oleate was demonstrated to be the cuticular contact sex pheromone of Dermacentor variabilis. This pheromone which has been termed the Mounting Sex Pheromone (MSP) was also demonstrated to be present on the surface of D. andersoni, Amblyomma maculatum and A. americanum. This contact sex pheromone enables males excited and attracted by 2,6-dichlorophenol to identify the female as a potential mating partner. The MSP is the second in the series of three sex pheromones guiding the hierarchy of behavioral responses which constitute tick courtship behavior. Tests with D. variabilis and D. andersoni showed that this pheromone …

Software Reliability Models, Syed Afzal Hossain

Mathematics & Statistics Theses & Dissertations

The problem considered here is the building of Non-homogeneous Poisson Process (NHPP) model. Currently existing popular NHPP process models like Goel-Okumoto (G-O) and Yamada et al models suffer from the drawback that the probability density function of the inter-failure times is an improper density function. This is because the event no failure in (0, oo] is allowed in these models. In real life situations we cannot draw sample(s) from such a population and also none of the moments of inter-failure times exist. Therefore, these models are unsuitable for modelling real software error data. On the other hand if the density …

Identification And Ranking Of Stressors In Nuclear Medicine Technology, Scott R. Sechrist

Community & Environmental Health Theses & Dissertations

The purpose of this study was to identify the most significant stressors in the field of nuclear medicine technology. A sample of convenience of 25 nuclear medicine technologists was used to generate a list of 35 stressors specific to the occupation. Sixty-three randomly selected nuclear medicine technologists responded to a mailed questionnaire which asked the technologist to assess the relative stressfulness of each of the 35 items on a scale of "0 to 1000". Data from the 59 valid responses indicated that equipment malfunctions, add on exams, uncooperative physicians, lack of staff, and uncooperative patients were the most significant stressors …

Simultaneous Determination Of 3-Methoxy-4-Hydroxyphenyl-Glycol, Homovanillic Acid, And 5-Hydroxyindoleacetic Acid In Plasma By High Performance Liquid Chromatography, Yung-Te Tseng

Chemistry & Biochemistry Theses & Dissertations

A rapid, reliable, and sensitive method for simultaneous determination of 3-methoxy-4-hydroxyphenylglycol (MHPG), Homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5- HIAA) in plasma is described. The method is based on high performance liquid chromatography with electrochemical detection. Samples were filtered with Amicon Centrifree micropartition systems and extracted with organic solvent before chromatography. Chromatographic separation of sample components was achieved isocratically in a C18 reverse-phase column. Quantitation was performed by measuring the peak height ratios of the sample components to an internal standard. Analytical recoveries ranged from 50.78 (SD 4.2%) to 67.94 (SD 3.28). Within-run coefficient of variations (CVs) ranged from 3.78 …

Nuclear Fragmentation Energy And Momentum Transfer Distributions In Relativistic Heavy-Ion Collisions, Ferdous Khan

Physics Theses & Dissertations

An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

Hemispheric Effects Of Response Hand And Concurrent Auditory And Visual Information Processing On Task Performance, Paula J. Guerette

Psychology Theses & Dissertations

Previous research (cf. Wickens, Mountford & Schreiner, 1981; Wickens & Sandry, 1982) has suggested that performance is facilitated by maintaining "integrity" between the hemisphere of information input, processing, and motor response. This task-hemispheric integrity has been found to exist during concurrent performance of verbal and spatial tasks, both of which are presented in a visual modality. The present study sought to examine whether task-hemispheric integrity exists during concurrent performance of a verbal and a spatial task when the verbal task is presented in an auditory modality and the spatial task(s) are presented in a visual modality. Fifty-six individuals (28M, 28F) …

Motivation And Job Satisfaction Of Direct Care Mental Health Practitioners In A Residential Treatment Center, Joann Zitt

Community & Environmental Health Theses & Dissertations

The purpose of this study was to determine the general Job satisfaction level of direct care mental health employees and to determine any significant differences in Job satisfaction levels between fulltime and part-time employees. The sample consisted of 60 direct care mental health employees In a residential treatment center in Virginia. There were 28 respondents for a 47% response rate.

The 20 item Minnesota Satisfaction Questionnaire (Short Form> and a demographic questionnaire were the survey instruments used. Respondents were satisfied with 13 Instrument items and undecided about seven of the items. Statistically significant differences occurred in relation to demographic variables …

Health Status And Perceived Health Care Needs Of Female Veterans Of The Armed Services, Nancy Einstein Camp

Community & Environmental Health Theses & Dissertations

The purpose of this study was to assess the occurrence of genderspecific health problems within the female veteran population of Tidewater, Virginia. A secondary purpose was to determine the perceived quality of care which the Veterans Administration delivers. The study was accomplished by receiving 149 mailed questionnaires regarding health status and health care received from the Veterans Administration. Chi square was utilized to determine significant differences between branch of service served and heal th status. Army veterans had significantly higher incidences of heart disease, diabetes and stomach ulcers. Among the other branches of service (Air Force. Navy, Marines, Coast Guard), …

Factors Determining Peripheral Vascular Disease Clients' Intent To Adhere To Prescribed Behaviors, Gretchen Grahn Hitchcock

Ellmer School of Nursing Theses & Dissertations

Motivation of clients with Peripheral Vascular Disease (PVD) to adhere to Recommended risk-reducing behaviors (RRB’s) was explored. The sample (n =30) was comprised of clients in a vascular physician group’s practice with a medical diagnosis of PVD. A nonexperimental, descriptive design was utilized to investigate how much variation in adherence to RRB’s by PVD clients could be accounted for by the client’s perceived effectiveness of a RRB and the client’s perceived difficulty in adhering to a RRB. A self-administered three part instrument, a demographic data form, and a self-administered qualitative data form were utilized to collect the data. Regression analysis …