A 3.5 gram quantity of β-(1→4)-glucan cellobiohydrolase C was purified from a commercial Trichoderma viride culture filtrate preparation, Meicelase P. Compared to the A and B forms, the C form of the cellobiohydrolase is present in the crude enzyme preparation in greater quantity and has a higher affinity for microcrystalline cellulose at pH 5. The C form was separated from the other forms by adsorption on a cellulose column, Following elution from the column, the cellobiohydrolase C was separated from other cellulose-adsorbed proteins by a batch separation on DEAE-Sephadex. The cellobiohydrolase C bound to the anion exchange at pH 5.0 is homogeneous by disc gel electrophoresis and identical to the "C₁" enzymes, F-II cellulase and hydrocellulase C, purified previously in this laboratory. Purified cellobiohydrolase C has an E₂₈₀^1% = 14.2and degrades both microcrystalline and phosphoric acid-swollen cellulose to cellobiose at the rates of 213 and 738 nmoles minute⁻¹ mg protein⁻¹, respectively. The cellobiohydrolase C contains 30.0, 5,5, 2,7 and 3.9 moles of mannose, glucose, galactose and glucosamine, respectively, per mole of enzyme (molecular weight 55,000). Methylation analysis of cellobiohydrolase glycopeptides indicates an average carbohydrate chain length of two residues. Consistent with the idea of several short carbohydrate chains is the release by alkaline borohydride treatment of cellobiohydrolase C of 89% of the neutral carbohydrate which is bound through an average of 19.4 0-glycosidic linkages to serine and threonine per molecule of enzyme, Glucosamine was not released from the protein by alkaline treatment suggesting a 4'-N-(2-acetamido-2-deoxy)-β-D-glucopyranosyl-L-asparagine linkage, Such an N-glycosidic linkage is consistent with the results of fractionation of the cellobiohydrolase glycopeptides by high voltage paper electrophoresis, filtration and paper chromatography which demonstrated that the glucosamine residues and the majority of the neutral carbohydrate are bound in different oligosaccharide chains. Only half of the glucosamine residues were destroyed by periodate oxidation pointing to the possible existence of both substituted di-N-acetylchitobiose units such as those found in other glycoproteins and unsubstituted single residues of glucosamine bound to the asparagine residues. Analysis of alkaline borohydride-released carbohydrate by high pressure liquid chromatography demonstrated that an average enzyme molecule contains 10,9 mono-, 2,0 di-, 4.9 tri-, and 1.2 tetra- and 0.4 pentasaccharide chains, The base stability of the linkages between the neutral monosaccharide residues in the chains and the destruction of all neutral carbohydrate periodate suggests that the (1→2) linkage is present but does not rule out the (1→6) linkage. Action of α-mannosidase indicates that at least some oligosaccharide chains contain α-mannose as the terminal residue, / Ph. D.

The assessment of the Virginia State Board of Education's 1973 Procedure for Adjusting Grievances mandated for use in all Virginia public school divisions reflects that school superintendents perceive the provisions relating to the workability of the procedure and its communicative implications in a more critical manner than do secondary school principals, elementary school principals or local education association presidents. No other relationships to commonly selected school division and respondent characteristics were found to exist. The three related factor groupings identified for comparison of significance of difference were: (1) panel requirements; (2) communicative implications; and (3) preliminary steps. On each factor group significant differences were found to exist between the perceptions of superintendents and the perceptions of secondary principals, elementary principals and local education association presidents collectively. The study provides means on perceptions of workability and communicative implications by respondent group for each selected significant provision or condition of the grievance procedure. The study provides a complete listing of all comments or statements offered by respondents relative to perceived restrictions of workability and/or communicative implications by individual provision or condition. / Ed. D.

The study was conducted to determine congruence in the role of principals of vocational-technical centers in Virginia as perceived by principals, superintendents, and teachers. Twenty-three out of the 24 vocational-technical centers in the state were included in the study. There were 23 superintendents, 23 principals, and 65 teachers from a 20 percent sample who provided usable returns. Design and method of research. A list of 78 items believed to be the functions of principals of vocational-technical centers was developed from the literature and subjected to a jury of experts. Forty-eight items were included in the final instrument which utilized a Likert-type scale to measure perceptions of the respondents. The mail questionnaire technique was used. Analysis of data. Means and standard deviations were obtained on each item for each of the three subgroups. Factor analysis of the items resulted in the identification of six factors underlying the 48 functions. A z-test was used to determine the differences between the sample of teachers, and the principals and superintendents on each factor. Conclusions 1. Principals and their superintendents have congruent perceptions of the role.of principals of vocational-technical centers in Virginia. 2. Teachers view the role of principals differently than do superintendents and principals. 3. Perception of the role of principals of vocational-technical centers by superintendents, principals, and teachers is not related to the size of the vocational-technical center; sex of staff members; years of formal education of staff members; years of experience as a vocational teacher; years of experience as an administrator of vocational programs; nor the years of work experience (in fields other than education) by staff members. 4. The 48 items in the research instrument constituted definite functions of principals of vocational-technical centers in Virginia. Recommendations 1. Present and prospective principals should be trained to perform the functions identified in the study. 2. Present and prospective staff personnel in role-defining groups should be made cognizant of the functions of the principal which were identified. 3. Teachers and administrators in vocational-technical centers should review the functions of the principal to locate and resolve any incongruences of perception which may prevail. 4. Studies should be conducted to determine specifically the research competencies needed by principals. 5. Research should be conducted to determine the functions of principals of vocational-technical centers which are common to other positions in vocational education. / Ph. D.

This dissertation examines the quality control situation where lots are either accepted or rejected on the basis of a single sample which is randomly selected from the lot. Judgment regarding the quality of an item is based on defined attributes which either conform to or deviate from prescribed standards. Traditionally, it has been assumed that no errors are introduced into the inspection process. While such as assumption eases the computational procedures involved in the evaluation of sampling schemes, it ignores considerable evidence that most inspection operations are error prone. This research investigates the statistical and economical considerations which may be involved in an inspection process subject to such inaccuracies. In the context of this research errors are introduced into the process when an item is erroneously classified as either good or bad. Good items classified as bad items are referred to as type I errors; conversely, bad items classified as good items are referred to as type II errors. Performance measures have been identified that are meaningful in establishing trend data from which to draw inferences concerning the effects of inspection errors. The purely statistical quality model is first evaluated for both the error free and error prone situations. The formulas for the average outgoing quality, AOQ, average total inspection, ATI, and the probability of accepting a lot, P_a are established for both situations of interest. For the error prone situation, a new probability mass function is defined which describes the conditional distribution governing the occurrence of observed defectives in a sample given the actual number of defectives in a sample. Other pertinent distributional considerations are developed and discussed. Typical numerical examples are used to illustrate the effects of both type I and type II errors which may occur either alone or in combination. The second part of this dissertation assumes that many quality schemes originate within the structure of an economic framework; in such cases the inspection criteria should appropriately be based on economic criteria. An economic based quality control model is formulated that is applicable to either the error free environment or the error prone environment. For the purpose of this research it is assumed that the prior distribution of defectives in a lot before the sample is formed is either described by a mixed binomial distribution or a Polya distribution. The distributional considerations pertinent to the model are fully developed within the text. Several numerical examples are evaluated to illustrate the selection of optimal sampling plans for inspection schemes subject to inaccuracies. The expected cost penalty incurred when using an optimal plan designed for an error free environment when errors actually exist was also investigated. Considerable data are presented which permits one to draw inferences pertaining to the importance of the assumed distribution. The data were presented in numerous tables and figures to aid in establishing the significant trends from which the consequences of inspection errors could be inferred. / Ph. D.

A series of experiments was conducted to assess the physiological effects of dietary PCB (Aroclor 1254) ingestion in white mice (Mus musculus) and in laboratory-reared white-footed mice (Peromyscus leucopus), and to determine if these effects were aggravated by group-caging or feed restriction. The underlying hypothesis was that PCBs may have different physiological effects, dependent on the nutritional status of the animal and the density of the population of which it is a member. The physiological characteristics examined were various organ weights, plasma corticoid levels, testicular spermatozoan reserves (right testis only) and hepatic microsomal enzyme activity. Pentobarbital- induced sleeping times were used as an index of enzyme activity. A competitive protein binding assay was used for determining plasma corticoid levels. PCBs (200 and 1000 ppm) in the diet of male white mice for 2 weeks significantly increased liver weights and decreased pentobarbital-induced sleeping times, whereas 100 ppm or below had no such effect in either male or female white mice. Male white-footed mice fed PCBs (100, 200 or 400 ppm) for 2 weeks and female white-footed mice fed PCBs (25, 36, 100 or 143 ppm) for 3 weeks exhibited greater liver weights and shorter sleeping times than control mice at all PCB levels. A significant PCB x Diet interaction effect was observed on liver weights and sleeping times in white mice. PCB feeding resulted in a greater increase in liver weights and a greater reduction in sleep times in feed-restricted than ad libitum fed mice. Plasma corticoid levels of white mice were significantly elevated by PCB-ingestion, group-caging and restrictive-feeding. In addition, significant PCB x Diet and PCB x Caging interaction effects were observed on corticoid levels. The PCB-induced increase in plasma corticoid levels was greater in grouped than in singly caged mice and in feed-restricted than ad libitum fed mice. Conversely, plasma corticoid levels were reduced in PCB-fed white-footed mice. PCB feeding did not significantly affect body weights, feed consumption or female reproductive organ weights. In addition, the proportion of white-footed mice exhibiting estrus as judged by vaginal smears was not altered by PCB feeding. In general the weight of the male reproductive organs were not affected by PCB ingestion. Testicular spermatozoa were significantly reduced by PCBs and grouping, whereas feed restriction did not affect spermatozoan counts. It was hypothesized that PCBs disrupted the spermatogenic cycle via reduction in androgen and/or gonadotrophin levels. No interactions were observed between PCBs and Diet or PCBs and Caging on any of the reproductive characteristics examined in either species. In summary, PCB ingestion resulted in the induction of hepatic microsomal enzymes of both white mice and white-footed mice, and in the mobilization of corticosteroids from the adrenals of white mice. These effects were intensified in white mice subjected simultaneously to either increased density or feed restriction. It was concluded that animals subjected to overcrowding or inanition are more susceptible to the toxicological effects of PCBs than are normal, healthy animals. / Ph. D.

The objectives of this study were to study whether a certain type marriage contract would be used if legal and available; to study the relationship between acceptance of a marriage contract and demographical characteristics of subjects; and to study which clauses in a marriage contracts would be most likely to be used. Two groups were surveyed: college students and respondents to a newspaper article. A marriage contract, consisting of ten clauses, was described for the subjects, who were then requested to complete an accompanying questionnaire that asked if they would use the contract; whether they thought the contract should be available for others; and whether they thought their fiancees or spouses would use the contract. In addition to these questions, the subjects were asked to designate, on a Likert-type scale, whether they would or would not use each of the ten clauses. Approximately 40 per cent of the college students and 50 percent of the newspaper respondents said they would use the contract described. Eighty per cent of the college students and 66 per cent of the newspaper respondents said they would like to see the contract available for others. Thirty per cent of the college students and 32 per cent of the newspaper respondents thought their spouses or fiancees would use the contract. The most popular clauses were those that dealt with traditional tasks within the marital dyad, while the least popular clauses dealt with innovative tasks, i.e., tasks not typically dealt with within the marital dyad. / M.S.

The purpose of this study was to determine the effects of years of trade experience, years of teaching experience, and semester credit hours of professional education on the classroom teaching performance of public secondary vocational industrial education instructors. A related problem of the study was to determine the differences in the ratings given by the five groups of raters chosen to evaluate the classroom teaching performance of instructors selected for the study. Ratings were given by (1) school administrators, (2) supervisors, (3) teacher-peers, (4) teachers on a self-rating, and (5) students. Dimensions which separated the groups of raters were named as well as factors emphasized by each. The following hypotheses were used to test the effects of these variables: Hypothesis I. Those instructors having low trade experience will receive lower classroom teaching performance ratings than those instructors having high trade experience. Hypothesis II. Those instructors having low teaching experience will receive lower classroom teaching performance ratings than those instructors having high teaching performance. Hypothesis III. Those instructors having low levels of professional education will receive lower classroom teaching performance ratings than those instructors having high levels of professional education. Hypothesis IV. There will be significant differences in the mean performance ratings of instructors as given by school administrators, supervisors, teacher-peers, teachers on a self-rating, and students. A stratified random sample of 72 instructors, based upon low and high levels of the 3 independent variables, were selected from among a population of 453 instructors of vocational industrial education in Virginia. Performance ratings were obtained on each of the 72 instructors by mail survey, using performance ratings developed for the study. A total of 406 of the 432 ratings mailed were returned (94 percent). The study used four statistical analyses to test the hypotheses and assess the findings of the study: multivariate analysis of variance (MANOVA), chi-square, stepwise discriminant analysis, and factor analysis. All hypotheses were tested at the .05 level. On the basis of these analyses the following conclusions were drawn: 1. Classroom teaching performance of vocational industrial education instructors is not significantly influenced by varying levels of trade experience, teaching experience, and professional education when ratings by the five groups are analyzed together. 2. Increased trade experience does significantly affect classroom teaching performance when rated by supervisors. 3. Classroom teaching performance significantly influenced by the interaction effects of high trade experience and hours of education when rated by supervisors. 4. Increased trade experience does significantly influence the classroom teaching performance of vocational industrial education instructors when rated by instructors on a self-rating. 5. Classroom teaching performance of vocational industrial education instructors is significantly affected by levels of professional education when rated by instructors on a self-rating. 6. Instructors with high levels of professional education also have high levels of vocational industrial education. 7. There are no significant differences in the performance ratings of school administrators, supervisors, teacher-peers, teachers on a self rating, and students. 8. Three dimensions identified as "Teaching Proficiency," "Instructor's Ability to Promote Learning," and "Relationship to Educational Surroundings" separate the performance ratings of the five groups. 9. Administrators, supervisors, and teacher-peers rate similarly when evaluating vocational industrial education instructors. Teachers (self-rating) and students rate differently from the other groups and from each other. 10. Performance evaluation factors can be identified which are common to certain groups and to group clusters. / Ed. D.

Ph. D.

Public utility regulation in the United States is carried out primarily by independent regulatory commissions. Though created to deal with problems which the courts and legislature had previously been at a loss to solve, the commission form of regulation has not been very successful. Students of regulation are in general agreement that commissions have failed to implement policies which serve the public interest, though the explanations for that failure are quite varied. By using time series data collected from the Virginia State Corporation Commission, it was possible to test the usefulness of several leading theories of regulatory behavior. The theories can be categorized primarily as either traditional or political economic--bureaucratic. The traditional theory and Stigler's captured bureaucracy theory were most consistent with the data. However, few implications could be drawn from the analysis which could be used to prescribe policy changes for improved commission performance. While all of the theories proved useful in explaining certain observed phenomena, they all suffered from serious shortcomings. None was useful as a general tool to describe behavior, and none was valuable for predicting agency behavior regarding a particular issue. The primary decision variable suggested by all of the theories is the budget of the agency. It was concluded that this measure is too narrow, whether we are dealing with a traditional theory, where budget is a measure of agency vitality, or a bureaucratic theory, where budget serves as the primary argument in the regulator's utility function. Rather, it is necessary to include other measures of both vitality and utility if one is to have a workable theory. The primary weakness of all of the theories is the failure to include the decision calculus of the agency's sponsor, and other interested groups, into the explanation of agency behavior. We conclude that if we are to construct a theory which is able to explain more than piecemeal the behavior of regulatory agencies, or in any way predict that behavior with respect to specific issues, such a theory must include interactions between the agency and all interested parties. / Ph. D.

A study to determine the effects of a new curriculum model for the biological sciences based on practical application of material, student research, and professional activities, all designed to promote student interest and involvement in course content, was initiated as a supplement to an existing introductory agronomy course during the Fall Quarter, 1973, at Virginia Polytechnic Institute and State University. Based on a pilot program established by the researcher at another institution, the treatment included investigation of research procedures, student utilization of the greenhouse and advanced research equipment, implementation of experimental designs, sampling techniques, and seminars. It was hypothesized that students exposed to the model would have better grades, higher class attendance, and improved attitudes toward the course and toward the agriculture profession than students who were not exposed to the model. Attitudes were determined by answers given on an attitude questionnaire which was developed by the researcher. Differences in attitudes, grades, and attendance between the two groups were analyzed for significance by a multivariate ANOVA. Results of this ANOVA showed that no significant differences existed at the .05 level for grades, attendance, and attitudes between the two groups. A factor analysis of the questionnaire indicated that various attitudes were tested, rather than a single attitude. However, resultant scores for five general attitudes believed to be determined by the questionnaire indicated that no differences in attitudes existed between the two groups. As a result of this study, it was concluded that the model, as implemented, had no effect on grades, class attendance, or attitudes. However, experience gained as a result of this study led to several major recommendations for refinements which would improve the validity and reliability of future, similar studies. / Ed. D.