Ph. D.

The purpose of the study was to analyze the level of understanding of farm management principles possessed by vocational agriculture instructors of young farmer programs in the State of Virginia. Specific objectives of the study were (1) to assess the level of understanding of farm management principles possessed by vocational agriculture instructors of Virginia young farmer programs, (2) to measure the relationship between variables of instructors and their level of understanding of farm management principles, (3) to determine the ranking of importance of twenty-one farm management instructional units, and (4) to determine the proportion of time allowed for farm management instruction in relation to the total time of instruction within young farmer programs. A 72 percent usable response was realized from the randomly selected sample which constituted data input for the study. Data collection instruments included a questionnaire developed by the researcher and the "management" section of The Agribusiness Achievement Test. The data collection procedure consisted of administering the questionnaire and test instrument to part of the sample subjects during the 1977 Virginia Young Farmers' Convention and mailing packets of data collection material to sample subjects who did not provide data during the Convention. Analysis of the data was accomplished using the following statistics: descriptive statistics, a one-way analysis of variance (ANOVA) to test null hypotheses for significance, and a stepwise inclusion multiple regression to determine which variables of the instructors were most related to their level of understanding of farm management principles. Of seven null hypotheses tested at the .05 alpha level, only one was rejected. The rejected null hypothesis was that there would be no difference in the level of understanding of farm management principles possessed by vocational agriculture instructors who have taken zero through 6.4 quarter hour credits, 6.5 through 12.4 quarter hour credits, or more than 12.5 quarter hour credits of business courses. However, the difference between the test means occurred between the 6.5 through 12.4 quarter hour credits group and the 12.5 or more quarter hour credits group. Years of teaching pre-secondary vocational agriculture and age of instructor, a negative predictor, were independent variables most related to the vocational agriculture instructors' level of understanding of farm management principles. Both of these variables were significant at the .05 alpha level. In ranking the importance of twenty-one farm management instructional units, Virginia vocational agriculture instructors identified financial topics as being the most important aspects of farm management instruction. Approximately a quarter of the time allowed for instruction within young farmer programs was devoted to teaching farm management. Recommendations generated from the findings of the study were (1) further studies should be conducted to assess what level of competence should be possessed by vocational agriculture instructors who teach young farmers, (2) advise prospective vocational agriculture instructors of young farmers to enroll in business courses, (3) conduct a study to determine the extent to which the twenty-one farm management instructional units are being taught in Virginia young farmer programs, (4) conduct a study to determine the importance of farm management instruction units as perceived by young farmer program participants, and (5) replicate this study in other states and compare results with those of this study. / Ed. D.

The task was to develop an evaluative tool that could be used to assess the existing status of intramural programs at private, two-year, co-educational and residential institutions. The researcher contacted various intramural directors and several officers of the National Junior College Athletic Association requesting endorsement of the study. The researcher then reviewed the literature pertaining to intramural evaluation and concluded that there was a need for a study of this nature. Private, residential, co-educational, two-year colleges that were located within the geographic confines of Region X of the National Junior College Athletic Association were asked to participate in the study. Region X includes North Carolina, South Carolina, Virginia and a portion of West Virginia. Components from the studies found in the review of literature were used to develop an interview questionnaire. The researcher then interviewed the intramural directors of the twelve participating colleges. The results of the interviews and the components of the review of literature were used to develop a model for evaluating college intramural programs. The model was forwarded to the intramural director of each participating institution accompanied by a request for appraisal. Two members of the researcher's doctoral committee recommended three individuals who were responsible for the direction of intramural programs at two-year institutions that did not meet the limits of the study. These persons also received a copy of the model and a request for appraisal. All of the individuals reviewing the model agreed that it was useful. Eight directors stated that they would use the model in their programs, and the remaining seven directors indicated that they would use portions of the model in their programs. The researcher recommended that: 1. The instrument be used to evaluate private, two-year, residential, co-educational colleges that are located outside of the geographic confines of The National Junior College Athletic Association. 2. The model be applied to four-year colleges with enrollments that are similar to those of the colleges participating in the study and that would meet the remaining limits of the study. 3. The instrument be forwarded to a random sampling of community college intramural directors with a request for the revisions that would make it applicable to this type of institution. 4. The instrument be forwarded to a random sampling of four-year college and university intramural directors with a request for the revisions that would make it applicable to this type of institution. 5. The instrument be submitted to the National Intramural and Recreational Sports Association for endorsement. / Ed. D.

Following a brief introduction to cellular automata, the formal notion of tessellation automata is advanced and a cellular computer using them is described. Potentially, this computer has the ability to do self-diagnosis and self-reconfiguration for internal faults without external assistance. Next, computational equivalence of Turing Machines and tessellation automata is demonstrated. This shows the powerful nature of tessellation automata. Following this, the existence of cyclic patterns with unique subpatterns is proven. These results are relied upon heavily for the remainder of this dissertation. Results which find the relation between growth rate and neighborhood index are then obtained and a solution to the synthesis problem is found. This demonstrates the existence of a local transformation whereby a given configuration can be generated from a single seed in the automaton. Next, results for single perturbations of the automaton are given and fall into two classes; restoration of equilibrium configurations and self-diagnosis. Restoration results demonstrate the existence of configurations which will immediately restore themselves following any single perturbation. Results obtained for self-diagnosis show that any single perturbation of certain configurations will be detected and the perturbed cell will be identified by its neighbors. Of particular interest is a result demonstrating the construction of a homomorphic self-diagnosing automaton for any given finite-state machine. Implications of the results obtained are discussed and some open problems are considered. / Ph. D.

The study was the first statewide study of risk management practices in the public school divisions of Virginia. The purposes of the study were to (1) examine the risk management practices of the public school divisions of Virginia, (2) probe the relationship between school division size and risk management practices in the public school divisions of Virginia, (3) probe the relationship between school division expenditure per pupil and risk management practices in the public school divisions of Virginia, (4) examine the roles of the Virginia State Department of Education and the State Commission of Insurance in assisting the public school divisions in the administration of the risk management program, (5) identify the legal mandatory requirements for insurance provisions in the public school divisions of Virginia, and (6) make recommendations for the improvement of the risk management program in the public school divisions of Virginia. The legal mandatory requirements for insurance provisions were identified. Criteria for effective risk management were developed, validated by a panel of experts and those accepted used as the bases for developing a questionnaire which also included information items designed to yield information for the improvement of risk management practices. School divisions were classified by size and expenditure per pupil and a questionnaire sent to all 129 operating public school divisions in Virginia. Responses from 104 school divisions indicated that sound policies and practices were followed in these areas: (1) risk management responsibility, (2) knowledge of the legal requirements for insurance, (3) establishment of risk management policy, (4) risk management program review, (5) property appraisal, (6) record keeping, (7) loss reporting, (8) property protection and safety, and (9) insurance coverage. Questionable risk management practices were reported in the following areas: (1) fire, safety, and hazard inspections, (2) programs for loss prevention and safety, (3) risk analysis, (4) selection of insurance companies, and (5) economies in purchasing insurance. School divisions performed risk management administration and record keeping functions effectively but were less effective in insurance practices and loss prevention and safety functions. Large school divisions were more effective in performing risk management practices than medium-size or small divisions. Medium size divisions were more effective than small divisions in performing risk management practices. Above average expenditure divisions were more effective in performing risk management practices than average or below average expenditure divisions. Below average expenditure divisions were slightly more effective in performing risk management practices than average expenditure divisions. The State Department of Education and the State Insurance Commission were reported to be of little assistance in the administration of the risk management program. Results of the data related to the criteria and information items were used as a basis for making recommendations to the State Department of Education, the State Insurance Commission, the State Legislature, and local school divisions. / Ed. D.

The direct decay induced ⁸²Br (or ⁸⁰Br) labelling by exposing the solid substrate molecules, such as deoxyuridine, L-tyrosine, guanosine, deoxycytodine, phenylalanine and acetic acid, to gaseous CF₃^82mBr (or CF₃^80mBr) was studied. The radiochemical yields of the brominated products are relatively small and range from 1% in the case of bromo-deoxyuridine to 11% for bromoacetic acid. The modification of this technique by adding Cl₂ gas to the reaction mixture improves the yields in several cases drastically (up to 80% for bromo-guanosine and bromo-L-tyrosine). Similar improvement can be achieved by exposing crystalline KBrO₃ for some time to CF₃^82mBr (or CF₃^80mBr) and dissolving subsequently the KBrO₃ in an acidic solution of the substrate. The radiochemical yields of ⁸⁰Br-5-bromodeoxyuridine and ⁸⁰Br-bromoacetic acid obtained by employing various modifications of the direct decay induced ⁸⁰Br labelling method which exposes substrate molecules to gaseous CF₃^80mBr are reported. The results indicate a drastic improvement of the amount of Br incorporated into these products if the labelling is accomplished by applying the “CF₃^80mBr-KBrO₃” gas exposure technique to induce a ⁸⁰Br for I exchange in the corresponding (inactive) iodo derivatives. The effect of several experimental conditions, such as the labelling time, the pH of the labelling medium, and the concentration of the substrate solutions, on the efficiency of the ⁸⁰Br incorporation via the “CF₃^80mBr-KBrO₃” gas exposure method resulting in carrier free radiobrominated compounds was investigated by using two model compounds, L-tyrosine and guanosine. The ⁸⁰Br labelling proceeds very rapidly in the case of the L-tyrosine and is fairly independent of “labelling time" and substrate concentration as long as a certain minimum amount of L-tyrosine is used. This is in contrast to the guanosine system where rapid secondary reactions reduce the initially high yields of ⁸⁰Br-guanosine at extended "labelling times” and where larger amounts of substrate are needed to produce optium yields. The chemical stability of ⁸⁰Br-guanosine and ⁸⁰Br-tyrosine was established by studying the dependence of the radiochemical yield on “labelling time” ( CF₃^80mBr-KBrO₃ gas exposure method ) and “post-labelling time” ( CF₃^80mBr-Cl₂ gas exposure method ). A radiochemical yield-time index is proposed to summarize the radiochemical yield dependence on “labelling” and “post-labelling” times in these two modified gas exposure labellings. It is hoped that this index will be helpful in making a priori judgements on the applicability of these labelled biomolecules for nuclear medical studies. Some preliminary mechanistic studies were carried out by using different reactants and model compound aniline. The proposed mechanism for both the direct excitation labelling and the CF₃^80mBr-KBrO₃ gas exposure method is electrophilic. / Ph. D.

Spills of toxic materials into bodies of water receiving industrial waste discharges can be prevented only if frequent or continuous assessments of wastewater quality can be made. Currently available methods can automatically measure individual physical or chemical waste components, but cannot assess toxicity caused by the interaction of components or the presence of an unsuspected material. Aquatic organisms, on the other hand, respond to their total environment and in this way integrate the effects of all the various chemical and physical waste parameters. The objectives of this study were to evaluate the possibility of using the continuously and automatically recorded physiological and/or behavioral responses of aquatic organisms to monitor the toxicity of industrial waste effluents. The requirements for this type of biological monitoring system and the suitability of various types of organismal responses for use in this manner were reviewed. This was followed by an evaluation of a method which used the computer-monitored ventilatory patterns of 12 bluegills (Lepomis macrochirus Rafinesque) to monitor the toxicity of an industrial waste effluent as it flowed into a river. No known toxic spills occurred in the effluent during any experiment, but a short-term exposure to acetone added to the effluent waste caused responses from the fish at concentrations which peaked near the 96 hour LC50 level. Some responses were also noted when no known toxicant was present; these are related to environmental disturbances and system design problems. Recommendations are made for the design of future biological monitoring units similar to the one tested, and the economic costs of using one of these new systems are discussed. / Ph. D.

Relationships between nontaxonomic aufwuchs community structure and functions were examined over a variety of environmental or physiological conditions in model streams to ascertain any direct relationships or covariance between indices of structure (dry weight, ash free dry weight, adenosine triphosphate and chlorophyll a) and function (primary productivity and assimilatory sulfate reduction). In eleven experiments, individual streams were treated with potential"enrichments" of sucrose, dextrose, ammonium nitrate, potassium dihydrogen phosphate, and toxicants including copper sulfate, potassium dichromate and chlorine, in order to elicit responses by the aufwuchs communities that accumulated on artificial substrates. The carbon-14 method was adapted and refined using a chamber for measurements of primary productivity in lotic systems. Assimilatory (sulfur-35) sulfate reduction was investigated as a method for estimating net microbial production rates. The ability of indices or ratios of structural and functional values to reduce variability and identify perturbed model streams relative to untreated streams was evaluated. In laboratory studies, assimilatory sulfate reduction closely followed growth rates in batch cultures of algae (Stigeoclonium sp., Navicula pelliculosa and Oscillatoria tenuis), bacteria (Pseudomonas flurescens, Enterobacter aerogenes and Bacillus subtilis) and fungi (Penicillium clavigerum, Mucor hiemalis and Coprinus patouillardii). Linear uptake kinetics of sulfur-35 sulfate during a six hour incubation period indicated that the process was active or energy mediated. Patterns of algal sulfate assimilation closely paralleled those for primary productivity. Bacterial and fungal sulfate assimilation rates were generally lower in the light than in the dark although the differences were not statistically significant. Observed rates of assimilatory sulfate reduction by cultures of algae, bacteria and fungi were affected by concentrations of organic carbon (glucose) in the media; at concentrations of glucose greater than 5 mg l⁻¹, dark sulfate uptake by algae was 77-98% of light uptake rates, and at glucose concentrations greater than 50 mg l⁻¹, bacterial and fungal sulfate assimilation rates did not increase proportionately with increasing glucose concentrations. The concentration of organic sulfur as as cysteine and methionine, that caused a decrease in the rates of sulfate assimilation, was between 10 and 100 S l⁻¹ for both the cultures and mixed populations in microcosms. No extracellular sulfur-containing products were found to be excreted by mixed populations in microcosms, and no"luxury" consumption of sulfur was observed. The use of assimilatory sulfate reduction rates to estimate net microbial productivity in aerobic systems was supported by the results from investigations with the cultures and microcosms. A reduction in accumulated matter (as indicated by dry weight, ash-free dry weight and ATP) and chlorophyll a on artificial substrates occurred in toxicant (copper, dichromate and chlorine) treated streams. Photosynthesis (carbon fixation) was most sensitive to the copper treatment and assimilatory sulfate reduction was affected most often by dichromate. The disaccharide, sucrose, significantly increased accumulated matter on substrates, but dextrose did not elicit similar responses. Phosphate and ammonium nitrate additions did not cause significant increases in aufwuchs production and were not considered to be limiting in this system. Net microbial productivity of aufwuchs and primary productivity were estimated by assimilatory sulfate reduction and carbon-14 fixation, respectively, with heterotrophic productivity being the difference. Overall, the reduced carbon compounds (sugar) and the toxicants resulted in stream aufwuchs communities dominated by heterotrophs. Indices used for condensation of information in the model stream experiments were generally unsuccessful in discerning perturbations. From all of the model stream experiments, measurements of functional parameters or indices calculated from functional measurements were significantly less variable than structural measurements or structurally based indices The perturbations or treatments did not reduce variability in the nontaxonomic structural and functional aspects measured. Direct correlations were found between: 1) dry weight and ash-free dry weight, 2) ash-free dry weight and assimilatory sulfate reduction, 3) ash-free dry weight and chlorophyll a, 4) chlorophyll a and assimilatory sulfate reduction, 5) chlorophyll a and primary productivity, 6) primary productivity and assimilatory sulfate reduction, and 7) and primary productivity and net microbial productivity. Field investigations of aufwuchs communities in the vicinity of a fossil-fueled power plant on the New River, Virginia, were inconclusive Variability in measurements overshadowed any differences in nontaxonomic structural and functional aspects that might have been attributed to an intermittently chlorinated thermal effluent. / Ph. D.

The purpose of this study was to investigate the relative effectiveness of three categories of variables--sociodemographic, personality, and social support system--in predicting persistence in Adult Basic Education. A particular emphasis was focused upon social support variables and the extent of their capacity to improve the level of prediction success which could be achieved by the other two categories of variables. This study was also concerned with identifying that combination of variables from all three categories which enabled the best possible prediction of persistence. The sample population for this study included 163 adult students enrolled in GED preparatory classes in three urban Virginia school districts. These students all attended classes two nights a week for a total of 5-6 hours. Sociodemographic data pertaining to age, race, sex, employment status, and time since last school attendance, were collected by means of a short questionnaire. Personality measures were acquired relating to self-confidence, achievement need, and affiliation need through use of the appropriate subscales of the Adjective Check List developed by Gough and Heilbrun (1952). Selections of particular sociodemographic and personality variables were based on their frequent inclusion in past studies of Adult Basic Education persistence and participation. This assured meaningful comparisons of the prediction effectiveness of these variables with that of the social support variables emphasized in the present study. Social support data were obtained pertaining to family, work, and church environments through use of selected subscales of the Social Climate Scales designed by Moos (1974). Composite measures were computed, consisting of the average of subscale scores pertaining to each environment area. A series of multiple linear regressions were performed to determine the order of best prediction among various combinations of variables and variable categories. The composite social support (environment average) variables proved poor predictors, a fact which raised doubts about the meaningfulness of the averaging procedure used to derive them. Selected individual subscales of the Social Climate Scales, by contrast, were better predictors of persistence than any of the sociodemographic and personality variables employed in the study. This was particularly true of the group environment subscales used to measure church leader support and member expressiveness. Despite the relative prediction effectiveness of some social support measures as compared to other variables, it should be noted that none of the predictor variables or variable categories employed in this study explained a substantial portion of persistence variance. The results of the study are thus of questionable practical value for Adult Basic Education teachers and administrators. They do, however, suggest some directions for future research. It is recommended that researchers continue to investigate social support systems of Adult Basic Education students. Social support measures are, on the whole, probably as effective predictors of ABE persistence as sociodemographic and personality measures, two categories of variables more frequently focused upon in previous studies. At the same time, many environmental factors can be addressed more directly and effectively by ABE practitioners than relatively fixed sociodemographic and personality characteristics. / Ed. D.

The purpose of this study was to investigate the development of the Conference on College Composition and Communication from 1949 through 1975 as a vehicle for the continuing professional education of its members and for the professionalization of the field of college composition teaching. A number of research questions were formulated to guide the investigation. These questions concerned (1) the circumstances under which the organization was founded, (2) its responses to educational movements and social forces, (3) its developing conception of its continuing education function, (4) its conception of and efforts toward professionalization, and (5) its relationship with its parent, the National Council of Teachers of English. The chief sources of information for this study included College Composition and Communication, the official journal of the organization; the programs for the annual conferences; correspondence, minutes, and reports housed in the headquarters of the National Council of Teachers of English in Urbana, Illinois; and a series of interviews with former officers of CCCC conducted in person, by telephone, and through the mail. In addition, some former officers lent materials from their personal files. Using the historical method, the study identified four distinct periods in the history of the organization: 1949-1954, during which the members came together to seek a new professional identity and to found a new organization; 1955-1958, which was characterized primarily by phenomenal growth in membership and expansion of activities; 1959-1967, during which CCCC conducted an inward search for new directions and emerged as a more mature and confident organization; and 1968-1975, a period in which CCCC's activities were marked particularly by a greatly increased concern for social justice. The researcher concluded that CCCC had become the major national forum for the continuing education of college composition teachers. It played a vital role in this process, primarily through its annual conferences and its quarterly journal. The format of the earliest conferences emphasized the workshop/discussion method. However, as the size of the meetings and the body of knowledge about the discipline of writing grew, conference topics evolved from general discussions of problems to the dissemination of more specialized research and theory depending on the leadership of a few persons. The journal evolved from little more than a pamphlet, printing reports of the conference sessions and a few articles on what specific colleges were doing in their freshman writing programs, to a widely recognized professional journal which has provided the major outlet for important research and theory development of many of the outstanding language scholars in the country. In addition, the organization also did much to further the professionalization of college composition teaching, particularly in the areas of developing a knowledge base for the profession, developing skills in applying that knowledge, and strengthening the control of composition teachers over the practice of their own profession. It was also observed, however, that the professionalization process might be speeded if CCCC could encourage more research in the teaching of composition, exert more control over access to the profession, and establish a code of ethics for the practice of the profession. It was further suggested that some of the actions resulting from the organization's overwhelming concern for social justice during the late 1960's and early 1970's might have weakened the effects of its other efforts to professionalize the field of college composition teaching. / Doctor of Education