Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

published_or_final_version / Zoology / Master / Master of Philosophy

Enteric pathogens in pool water can be unintentionally ingested during swimming, increasing the risk of Acute Gastrointestinal Illness. Swimmer activities and behaviors influence pool water ingestion rates, and can be quantified for use in risk assessment. Enteric infection risk estimates help identify data gaps, areas to focus resources, and research needs. Primary objectives of this study were to develop electronic, self-administered "exposure" and "pool operations" questionnaires; to gather swimmer behavior and activity data for use in risk assessment; and to estimate Cryptosporidium parvum infection risk in swimmers. Results were used to identify data gaps and future research needs relative to treated recreational water. To achieve these objectives, 126 swimmers were recruited at four pool sites in Tucson, Arizona, video-taped, and asked to complete a post-swim questionnaire. Forty-six of the 126 swimmers submitted a 24 hr post-swim urine sample for quantifying pool water ingestion. Head submersion frequency and duration and splashes to the face were observed and quantified in video analysis, and activities and behaviors were reported on the exposure questionnaire. Variable data were analyzed for associations with pool water ingestion estimated by urinalysis. Results indicate questionnaires can be self-administered electronically; the exposure questionnaire can be used to estimate ingestion magnitude in place of urinalysis; leisure swimming activities (diving, playing, splashing, wading, sitting) and frequency of face splashes are ingestion exposure factors; and that Cryptosporidium infection risk is greatest among leisure swimmers. Other activities observed and suspected of having associations with ingestion were short submersion durations (<1 sec), and spitting and spouting water. More research and resources focused on improving treated recreational water environments and reducing risks among swimmers are needed. Developing an indicator organism test representative of Cryptosporidium, a monitoring program for treated recreational water, education aimed at leisure swimmer, and routine engineering and administrative controls are recommended. Swimming is a unique activity that can be enjoyed by people of all ages and abilities. Controlling hazards in pool environments reduces Recreational Waterborne Illness risks associated with pool water ingestion and improves the health and safety of swimmers.

Rats are nocturnal animals, their ingestive behaviours show circadian rhythms and the suprachiasmatic nuclei (SCN) of the hypothalamus are the primary pacemaker of these rhythms. Serotonin (5-HT) is one of the most abundant neurotransmitter in the SCN and it is involved in the regulation of ingestive behaviour. In this study, we compared food and water intakes of male adult Wistar rats infused during 7 days with serotonin (2.5 nmol/24h) or artificial cerebrospinal fluid (CSF) in the SCN in a three-way selection of macronutrients. Within 5-HT infusion, nocturnal and diurnal water intakes, and the nocturnal caloric intake from the protein diet were significantly lower than those of the CSF infused group. Decrease in water consumption was most significant in the early and middle dark phases. Besides, increased diurnal energy intake and decreased nocturnal energy intake were observed during 5-HT and CSF infusion. In conclusion, this first chronic and continuous infusion work on 5-HT in the SCN specifically disrupted the circadian rhythmicities in water and protein consumptions.

Dietary selection involves the process of relating the postingestional consequences of eating a food to its sensory characteristics. Diet texture, the most plausible sensory characteristic affecting ingestion, may play an important role in the control of food selection. In this study, we compared the circadian rhythmicity of protein- and carbohydrate-rich diet ingestion of adult male Wistar rats presented with diets in different textural forms (high-protein powder and high-carbohydrate granular (HPP-HCG) diets vs. high-protein granular and high-carbohydrate powder (HPG-HCP) diets) during 15 days. Rats fed HPP-HCG diets selected significantly less protein (kcal) vs. rats fed HPG-HCP diets, during the 24 h, 12 h dark phase and the 4 h early and late dark phases. Carbohydrate intakes of the two dietary groups were not significantly different. Total caloric intake for HPG-HCP group was significantly higher than that of HPP-HCG group during the 24 h and 12 h dark phase. In conclusion, macronutrient-rich diets presented in different textural forms alter the circadian rhythmicity of protein-rich diet ingestion and total energy intake.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [91]-108).

Thesis (M. Communication Pathology)--University of Pretoria, 2000. / Summary in English and Afrikaans. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1982.

Thesis (M.S.)--University of Michigan, 1982.