The purpose of this research was to characterize the antibody-mediated inhibition of horseradish peroxidase activity. Inhibition of enzyme activity was determined when alternate substrates were used. Typical biphasic patterns of inhibition were observed with each of five electron donors and three hydroperoxides. In no case was inhibition complete (100%). Inhibition assays with varied substrate concentrations revealed a dependence of anticatalytic activity upon the hydroperoxide concentration. Increased hydroperoxide concentration elevated inhibition levels. Inhibition is not dependent upon the electron donor concentration. The dependence of inhibition levels on hydroperoxide concentration suggests that antibody may make the horseradish peroxidase basic isoenzyme more susceptible to peroxide inactivation. Kinetic data show increased enzyme affinity for hydrogen peroxide in the presence of antibody. In addition, acidic peroxidases that are less susceptible to peroxide are poorly inhibited by antibasic horseradish peroxidase. Spectrophotometric experiments with an electron donor analogue indicated that antibody does not inhibit horseradish peroxidase activity by preventing electron donor binding. Inhibitory antibody binding sites could not be determined because fragments of the enzyme capable of binding inhibitory antibody could not be produced. Antisera prepared against acidic horseradish peroxidase isoenzymes were used in immunological procedures (precipitation, anticatalytic assays) to assess the homology of horseradish, radish and turnip peroxidases. Acidic horseradish peroxidases with similar physicochemical properties are distinguishable by immunological methods. Interspecies relationships are stronger among acidic peroxidases than relationships between acidic and basic horseradish isoenzymes. These results support an evolutionary conservation of acidic isoenzymes and suggest that each isoenzyme group catalyzes specialized plant functions. / M.S.

In the past few years, great strides have been made toward simplification and improvement of the classical methods of the design of circular tanks. The need for a fast and efficient method by which engineers may determine the "indeterminate" stresses that exist in the walls and floors of circular tanks, of steel and concrete, has long been recognized. A simplified approach to the problem, which has been used by engineers for many years, merely employs the basic history of liquid pressure on the walls of pipes of large diameter. However, the use of this theory results in great waste of structural material. The advent of modern methods of placing reinforce concrete and the use of large, shallow settling tanks, has necessitated a more thorough investigation of the stress distribution both in tension and in bending, which exists in the tank wall, through the continuity between floor and wall. Credit for the introduction of a more rigorous analysis of the stresses in circular concrete tanks may be given to Mr. George S. Salter (1), whose theory has become quite popular since 1940, although the U.S. Navy (2) published charts and tables of tank stress distribution as early as 1924. A few existing theories will be discussed in Section II. Although there have been very few failures of tank structures, a more thorough study of tank design is still needed by the engineering profession. It is hoped that this thesis may, to some extent, contribute to forming a basis for future improvement and simplification of the popular methods of tank design. / Master of Science

The biology of Anisota senatoria J. E. Smith (Lepidoptera: Saturniidae) was examined through ecological studies of within-tree distribution and dispersion, and the influence of a tree growth regulator on development and survival. Biological characteristics examined egg mass size and development, pheromone attraction, response to blacklight traps, adult emergence, laboratory development, pupal mortality and comparison of first versus second generation development time, fecundity and amount of infestation. Within-tree distribution of life stages showed significant differences between low (1.7-3.6 min height), middle (3.7-5.5 m) and high (5.6-7.6 m) strata. Dispersion indices generated from Taylor’s power law showed aggregation was greatest among early instars, followed by third instars and late instars. A fixed level precision sampling plan was developed based on the number of eggs and early instars present in low strata. The tree growth regulator paclobutrazol significantly reduced Q. Phellos L., willow oak, growth, especially one and two years posttreatment. One year posttreatment, paclobutrazol treatments significantly slowed development and decreased survival of early instars, but the opposite relationship was found with late instars. Behavior studies showed that increased A. senatoria survival occurred with increased group size. Laboratory and field experiments revealed critical group sizes for survival of 1-3 larvae and between 25-50 larvae. Anisota senatoria defoliation impact and frass were measured. Growth and root starch were significantly reduced with increased defoliation in Quercus palustris Muench., pin oak, but Q. phellos root starch was not reduced. Reduction in starch content in Q. palustris may have been related to additional stress factors. Landscape fabrics were a reliable sampling method for frass. Frass was used as a method for differentiating larval instars and predicted defoliatioonf Q. palustris. An integrated pest management (IPM) program was developed that included information on native parasites, host plant preference, a citizen survey, and aesthetic indicators. Four egg parasite species including an Aprostocetus new species, five larval parasites and eight hyperparasites were collected. Host plant preference experiments indicated that Q. alba L., white oak, was least preferred by A. senatoria. A citizen survey provided a framework for designing an IPM program. Monitoring and establishing an aesthetic injury level of 25% defoliation decreased pesticide volume without an attendant increase in damage. The number of egg masses (threshold) that caused 25% defoliation ranged from one to nine. / Ph. D.

Successful management of conversations can bind human beings together in linguistic communication. Learning how to manage conversations in a second language is as important as learning the language’s grammatical structures. Among the conversational management strategies commonly employed is the use of pauses to buy time keeping conversational channels open, organize thoughts, or search for a suitable response. This study described and compared these pauses, called wait-time, as they were used with other conversational management strategies by first- and second-year students and by third-year students engaged in conversations in three different conversational settings: a teacher-controlled conversation setting, a student-controlled planning setting, both in Spanish; and a researcher-controlled setting in English to compare and contrast patterns of interaction in the target language and English. Audio recordings made during the 1986 Virginia Tech Foreign Language Camps were transcribed and coded using a listing of conversational management strategies by Kramsch (1981) and the Observational System for Instructional Analysis IV (OSIA IV) developed by Hough (1980). The following results were obtained from the study: (a) two kinds of wait-time are present in conversations: inter-speaker (2.41 seconds mean duration) and intra-speaker (1 .57 seconds mean duration); (b) speakers pause more frequently and for shorter periods of time within their own utterances than they do between the utterances of different speakers; (c) advanced Spanish students accord each other longer pauses between utterances than first- and second-year students; and (d) conversational management strategies of taking the floor, linking to previous points and reactive listening were used most as participants gave and asked for information. / Ed. D.

Mon projet de recherche s'est articulé autour de l'expérience de la marche comme état d'être et de la motricité du corps en lien avec l'activité physique. Je donne un caractère artistique à la marche par l'intermédiaire de la photographie, du dessin, de l'univers vidéographique et sonore. J'évoque les sensations que génère la relation entre la psyché et la corporalité dans l'acte de marcher par une poésie d'images en mouvements. Le mémoire est rédigé en trois chapitres chacun d'eux faisant référence à une étape accomplie: l'étape préparatoire, l'étape de réalisation et l'étape du retour au calme. Je suis partie le sac au dos, des ailes aux semelles, l'horizon au fond des yeux afin de marcher, dessiner et écrire pour visionner les différentes étapes d'un voyage rituel comme pourrait le faire un navigateur regardant par les hublots de son navire.

The purpose of this study was to learn about mentoring relationships in a principal preparation program, the contexts in which they developed, and the influence of personality traits on relationships. Relationships between four pairs of mentors and proteges were described using data collected with a questionnaire, a semantic differential, the FIRO-B (Fundamental Interpersonal Relations Orientation), and in-depth interviews. Analyses of data identified variables associated with mentor-protege relationships and their influence on relationships. The variables that played a role in the formation of relationships were age, gender, experience, proximity, school division support, program design, time, and family support. The semantic differential proved to be an indicator of relationships while FIRO-B was inconclusive. This study should be beneficial to mentors, proteges, and others interested in learning more about mentoring relationships in educational administration. / Ed. D.

Rail vehicle designers and analysts can benefit from the results of vehicle parameter estimation. Using this technique, they can determine the effects of suspension design decisions, and they can reduce the amount of on-track testing required to qualify new designs for service. This work addresses two major issues: the determination of parameter identifiability and the estimation of rail vehicle parameters from laboratory tests. Usually, the identifiability issue should be addressed first since identifiability determines the number of independent parameters that can be estimated. The general issues of identifiability and parameter estimation are discussed. Two identifiability tests are explored in-depth, as is a Bayesian least-squares parameter estimation method. Laboratory tests from a lightweight intermodal rail vehicle with single-axle trucks provided the data for the parameter estimation. The test setup and a simple vehicle mathematical model provided the structure for the identifiability determination. This work shows that identifiability and estimation issues closely interact. Even if a system is not identifiable, the Bayesian estimation method can return results. Thus, the Bayesian method can instill false confidence in the validity of the estimation results. Estimation of experimental data with a linear model provided values within one percent for the mass and damped natural frequency, and ten percent for the peak amplitude. Excellent agreement with the experimental data was obtained for frequencies above the resonant peak and for very low frequencies. Error at frequencies slightly below the resonant peak, however, indicated the vehicle contained significant nonlinearities. To achieve closer agreement between model response and test response at these frequencies, a nonlinear vehicle model is needed. / Master of Science

The strategic importance of the adoption of innovative processing technologies was analyzed for building products businesses. This study examined the two components of wood building products businesses: the structural panel industry and the softwood Iumber industry. To ensure that the relevance of adopting of innovative processing technologies was examined within an accurate contextual environment, additional important strategies and performance were also measured. A mail survey of the seventy-five largest North American producers of these two products provided the primary data necessary to investigate the strategic importance of process technology adoption, forward vertical integration, relative market share, grade sector focus, and investment intensity on firm performance as measured by profitability surrogates and changes in relative market share. This survey collected direct measures of the proportion of 1987 production produced by respondent firms that used controlled distribution channels and each of twentythree processes indicative of innovative technologies in the manufacture of building products. Information concerning the other strategic and performance factors was collected from secondary data sources. Results indicate that the adoption of innovative processing technologies has a positive impact on firm profitability. Investment intensity and grade sector focus also contributed to superior profitability. Forward vertical integration, and relative market share had no impact in differences between performance levels for the firms studied. Technologies were examined for underlying dimensions that group different process technologies together. Firms were clustered according to their level of adoption of innovative processing technologies and these clusters were then described according to a variety of firm-dependent characteristics, strategies, and performance measures. A strategy-performance model was developed for standardized, industrial product-markets and empirically tested using the data collected for the building products industry as an industry representative of this type of competitive environment. / Ph. D.