Lake Moomaw, a 1,024-ha flood control reservoir in Bath and Allegheny counties, Virginia contains a migratory population of smallmouth bass that congregate in the headwaters of the reservoir during the spring spawning period, where they are vulnerable to a shore-based, harvest-oriented fishery. The extent of this fishery and resulting effects on the small mouth bass population were analyzed by means of a creel survey in the headwaters area during the spring spawning seasons of 1995 and 1996. Effort, catch, and harvest, as well as user characteristics and motivations data were obtained from direct interviews with anglers using this area. Estimates for 1995 indicated extensive fishing pressure per ha, with 1,167 angler hours per ha spent fishing for smallmouth bass in the headwaters, while in 1996 almost 1,400 angler hours per ha were spent in this area. Catch and harvest rates were relatively low and sustainable during both years, with 124 small mouth bass caught and 82 harvested in 1995, while 318 small mouth bass were caught and 222 harvested in 1996. An extensive capture-recapture study yielded estimates of exploitation rates for small mouth bass in the reservoir of 12- 15% annually. Exploitation of the whole-lake population occurring in the spring headwaters fishery was estimated at 4-6%, while the exploitation rate on the subset of the population using the headwaters during the spring was 11-14%. Analysis of movements of snlallmouth bass in the reservoir using ultrasonic telemetry and dart tag recaptures indicated that the subset of the population using the headwaters was mainly drawn from the upper and middle portions of the reservoir, and that significant amounts of spawning occurred in the lower section of the reservoir as well. Areas used by smallmouth bass for reproduction were documented with summer and fall electrofishing to determine relative abundance of young-of-the-year smallmouth bass in the reservoir, and showed spawning to take place throughout the reservoir. Densities of young-of-the-year shifted as fall progressed, with highest densities in the middle portion of the reservoir in early fall, indicating that reproductive inputs from the headwaters were realized in the lake as fall progressed. The headwaters fishery is a high-profile activity which, during 1995-96, had a low and sustainable impact on the Lake Moomaw smallmouth bass population. / Master of Science

Certaines études suggèrent que des pigeons estiment la durée d’un stimulus en ignorant les moments pendant lesquels le stimulus disparaît. (Cabeza de Vaca, Brown & Hemmes, 1994). Plusieurs recherches dénotent une dégradation de l’information temporelle accumulée avant l'interruption. L’expérience 1 de la présente étude vérifie si l’information temporelle accumulée avant l’interruption se dégrade dans une tâche de production temporelle. Les expériences 2-3 vérifient s’il y a partage des ressources attentionnelles avant l’interruption entre l’attente de celle-ci et la production temporelle. Dans ces expériences, les participants produisent, au rythme d’un son, un intervalle temporel, cessent de traiter le temps lorsque le son s'arrête et recommencent à traiter celui-ci lorsqu’il revient. Dans l’expérience 3, des essais sans interruption sont introduits. Les résultats suggèrent que les humains interrompent l’accumulation sans qu’il y ait dégradation de l'information temporelle et partagent leurs ressources attentionnelles créant un allongement des intervalles produits en fonction de la durée précédant l'interruption.

Le but de la présente recherche est d'étudier l'influence du stress sur le sommeil chez des personnes qui dorment bien et qui souffrent d'insomnie. L'échantillon se compose de 27 bons dormeurs, 22 insomniaques n'utilisant pas de médicaments pour dormir et 18 insomniaques en faisant l'usage. Les résultats indiquent que les insomniaques perçoivent le stress comme étant plus difficile à prévoir et à contrôler que les bons dormeurs et ils en sont plus envahis que ces derniers. De plus, l'intensité des événements négatifs vécus durant la dernière année, l'impact du stress quotidien ainsi que l'état d'activation somatique et cognitive au coucher sont aussi plus élevés chez les insomniaques que chez les bons dormeurs. Aucune différence n'est toutefois observée entre les deux groupes d'insomniaques pour l'ensemble des variables associées au stress. Deux variables, soit l'impact du stress quotidien ainsi que les stratégies de gestion du stress orientées vers l'émotion, prédisent mieux l'état d'activation au coucher. La perception du stress est pour sa part le meilleur prédicteur de la qualité du sommeil. L'efficacité du sommeil est significativement reliée à une seule variable, soit l'impact du stress quotidien.

La présente recherche étudie les stratégies de contrôle de pensées, particulièrement l'évitement chez les gens souffrant d'insomnie. Les participants sont soumis à une procédure d'évaluation incluant des entrevues et des questionnaires portant sur l'anxiété, l'insomnie et les stratégies de contrôle de pensées. Cinquante personnes forment les groupes de bons dormeurs (n=20), d'insomniaques (n=14) et d'insomniaques souffrant de trouble d'anxiété généralisée (TAG) en comorbidité (n=16). Les résultats démontrent que les insomniaques TAG ont une activité cognitive plus importante à l'heure du coucher que les insomniaques sans TAG. Ces derniers ont une activité cognitive plus intense que les bons dormeurs. Les bons dormeurs évaluent leurs stratégies comme étant plus efficaces que les deux autres groupes. Enfin, les résultats suggèrent que l'utilisation de l'évitement est une dimension à considérer davantage chez les insomniaques TAG. Les particularités retrouvées chez les gens souffrant d'insomnie avec ou sans TAG en comorbidité, sur le plan cognitif, devraient être prises en considération dans l'évaluation et le traitement de l'insomnie.

Plusieurs chercheurs indiquent que le déficit d'inhibition est central à la symptomatologie de la schizophrénie. Toutefois, la nature exacte de ce déficit n'est pas précisée. Ce mémoire utilise un paradigme d'amorçage négatif (AN) pour évaluer séparément les capacités d'inhibition de l'identité et de la localisation des distracteurs. Des patients schizophrènes et leurs contrôles ont complété l'épreuve. Les résultats obtenus montrent un déficit d'inhibition de la localisation des distracteurs chez les patients. On observe un effet d'amorçage négatif dans la condition spatiale et l'absence d'effet d'AN dans la condition d'identité pour les sujets contrôles. Nous proposons, à la suite d'une analyse de 1 'expérimentation, que les processus d'inhibition impliqués dans l'AN sont utilisés de façon stratégique. Il semble que cet effet est suscité par les caractéristiques des stimuli uniquement lorsqu'ils sont nécessaires à la réussite de la tâche.

De nombreuses différences existent chez les patients diabétiques quant au type de diabète (type 1 et 2) et au niveau de l’adaptation psychosociale qu’ils manifestent. Le but de cette recherche est d’évaluer la stabilité du MCP-D en comparant la solution de profil des patients diabétiques de type 2 à celle des patients diabétiques de type 1. La stabilité des profils a été évaluée auprès de 168 patients diabétiques, soit 82 de type 1 et 86 de type 2. Les résultats des analyses sur l’appartenance des patients diabétiques aux profils du MCP-D ont démontré que 83% des patients diabétiques de type 1 et 80 % de type 2 ont été assignés à l’un des 3 profils, ce qui permet d’inférer que la solution de profil est relativement stable pour les 2 types de diabète. De plus, aucune différence significative n’a été relevée entre la proportion de patients diabétiques de type 1 et 2 classés dans les profils. La validation externe des profils, utilisant des mesures psychologiques générales et spécifiques et d’autres liées aux activités d’autogestion, démontre que les patients diabétiques de type 1, lorsque assignés à un profil particulier, possèdent les mêmes caractéristiques que ceux de type 2 classés dans le même profil. De plus, les variables socio-démographiques, reliées à l’histoire médicale et la désirabilité sociale ne semble pas être des substitut aux variables psychosociales du MCP-D. La poursuite de la validation a permis de conclure que les 3 profils du MCP-D sont stables pour les différentes maladies que constitue le diabète de type 1 et de type 2 et pourrait donner lieu à des implications cliniques significatives pour le traitement des patients diabétiques.

With increased use of pallets constructed utilizing structural panel decks, there is a need for a standardized, reliability-based design system, PDS-PANEL, to assist in the design and manufacture of panel-deck pallets. The primary objective of this research was to develop finite element models which predict the static bending behavior of pallets with at least one panel deck. stringer and block pallets were modeled using plate elements to simulate deck behavior and were validated by comparing predicted deflections to experimentally measured deflections. Differences were considerably less than the allowable 15 percent for both stringer and block models. Sensitivity studies conducted with these models provided a rational basis to simplify models for use in the existing PDS-PANEL program developed at Virginia Polytechnic Institute & State University. Simplified models were required to have solution times of less than 2 minutes on a 286 type or more powerful personal computer (PC). / Ph. D.

Laboratory and field experiments were conducted with six populations of Chironomus riparius to test for variation among the populations in life history parameters such as growth. mortality and/or reproductive rates. Egg masses of C. riparius from five field populations and one laboratory population were obtained and used to initiate laboratory cultures for experimentation. Environmental effects on life history variations could be ruled out because experiments were conducted with larvae that had been reared in the laboratory for several generations under identical conditions. Populations were compared under a variety of experimental conditions to test whether they would respond similarly, if genetically similar. or differently, if their genotypes were different. The populations were subjected to a variety of experimental conditions in the laboratory in which temperature and food quality were manipulated. The population collected from Strouble''s Creek. Virginia demonstrated a pattern of high growth rate and low mortality rate. While the population collected from the final clarifier at the Madison, Wisconsin sewage treatment plant showed a pattern of low growth rate and high mortality rate. When several populations were transplanted into a high chlorine environment at the Blacksburg, Virginia sewage treatment plant, the population that had been previously exposed to the chlorine showed a significantly lower mortality rate than the other populations. A series of toxicity tests revealed different sensitivities among several populations to an experimental pesticide. Differences among populations were also found in numbers of egg masses produced, numbers of eggs per egg mass, length of time until the onset of adult emergence, and the overall length of the emergence period. The results of this study show the importance of genetic differences among populations of C. riparius. Many commonly measured life history parameters that are usually assumed to vary primarily from differences in environment have been shown to vary as well from underlying genetic differences between populations. The role of genetics should be assessed, whenever possible. in studies where comparisons between populations of aquatic insects are made, in order to determine the degree to which genetics and environmental variables contribute to observed population differences. / Ph. D.

Within this Book is a glimpse of the world that was brought forth from my thesis work. When beginning to find the place of the thesis work, I assumed that I should be making an architectural construction at the scale of building, the scale in which I then believed architecture existed. Knowing that I wanted to find a way of making where I could physically construct every thing I was to make in a careful architectural manner, I hoped that this consideration would lend itself to the design of a building (the kind that people can physically inhabit). What I found was that the building I am making is of a different sort of inhabiting, and that I have been able, through making, to hone my tools. With these I can come to a site(situation), and begin to make decisions that are in the world of architecture. The textile article, one made of woven fibre, is continually referenced throughout this thesis. Being assured of the very close connection between fabric and building (Oxford English Dictionary definition), A Building as being a Fabric, I have explored the literal physical kinds of connections to which fabric lends itself. Fabric items (those made with fibre) engage the world of the temporary connection (a button, a tied closure), because of this, the exploration of temporary construction was naturally a part of this thesis. Finding that though physically temporary, the connection between a site and its construction, can have a presence that has more permanence in its temporal quality than if it were to have a more physical permanence. During the making of each thing, it became clear to me that the woven must have limits; there is a beginning and a completion (Looms have a frame for construction with particular dimensional limits). What is that beginning and completion in each of the thesis projects, what is the construction? In order to have a metaphorical and physical understanding for myself it has been necessary to bring back that question into the realm of the textile and fabric article. What do you do with fabric? It is sewn into particular constructions. This particularity has the beginnings and completions to transform fabric into made things. The woven stuff can go on forever but it takes decision and an idea to take the material into a physical realization. It occurred to me that when one uses material in any form to create a construction, there are particular decisions made that have to stop the woven thing and bind it so that it can be made into something in particular. It seems that within the world of architecture it is important to know when to stop an action and when to make a decision, not letting something default into indistinguishablity. / Master of Architecture

Initial formal studies of three dimensional cubic objects and their affects on space and light lead to the design of complex living arrangements that take the form of apartments. Rooms within the building volumes develop interdependent relationships that blur the distinction between inside and outside space and emphasis the private and public aspects of a clustered arrangement of buildings. / Master of Architecture