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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Survival of Vibrio vulnificus and Escherichia coli in artificially and naturally infected oyster (Crassostrea virginica) tissues during storage in spray- and immersion-type live holding systems

Colby, Jhung-Won 19 June 2006 (has links)
Live holding systems are used as temporary storage facilities for shellfish. The potential for mishandling of shellfish stored in these systems is high. The objective of the project was to examine the effects of storing oysters in a spray and an immersion systems on the survival of Escherichia coli and Vibrio vulnificus within the oysters. The effects of physiological stress imposed on oysters, as a result of interstate shipping, were examined by monitoring the level of E. coli in these oysters during storage in a spray tank. The survival rates of naturally-present E. coli and V. vulnificus in oysters were also observed. The research examined the distribution of artificially- and naturally-present V. vulnificus in oyster tissues during storage in an immersion system. There was no significant difference (p = 0.12) in the artificially-inoculated bacterial population of oysters after 120 hr of storage in a spray live holding tank. The level of E. coli in oysters which were subject to physiological stress did not change significantly (p = 0.30) after 96 hr in the spray tank. Naturally-present E. coli and V. vulnificus in oysters at harvest persisted during the 72 hr storage in the spray tank. V. vulnificus was loosely associated with mucus on the surfaces of the adductor and the mantle tissues in artificially-inoculated oysters. As a result, the bacterial level was reduced on these surfaces during the 72 hr of depuration. V. vulnificus on the gills and the digestive system of artificially-inoculated oysters may become entrapped in cilia and mucus. There was no significant reduction in the bacterial population on the gills (p = 0.11) and on the digestive system (p =0.21). There was no significant difference in the population of V. vulnificus in the adductor muscle (p = 0.37), the mantle (p = 0.16), the gills (p = 0.5), and the digestive system (p = 0.5) of summer oysters naturally-infected with the bacterium. It seems unlikely that depuration of V. vulnificus from oysters naturally harboring the bacterium may be effective. / Ph. D.
412

The relationship of social support, emotional expression, and health status: a LISREL analysis of conceptual models

Putnam, Dana Evan 07 June 2006 (has links)
The present study investigated the relationship between hostility, self concealment, social support, stress, and health. A path model was proposed, evaluated, and modified using the linear structural relations (LISREL) method of latent variable path analysis. Subjects were 402 undergraduate psychology students at Virginia Polytechnic Institute and State University. All subjects completed self-report measures initially and 293 subjects completed mailed follow-up measures of health status one semester later. Health care utilization data was obtained from the Student Health Services. Results indicated that social support had strong direct effects, but relatively weak indirect effects on health. Whereas, hostility and self-concealment were found to have indirect effects, but not direct effects, on health. Hostility affected health via effects on social support, stress, and self-concealment. Self-concealment affected health via its effect on stress, and stress directly affected health. These findings suggest that emotional expression has an important influence on the relationship between social support, stress, and health. / Ph. D.
413

An evaluation of sensory comfort components of survey questionnaires used for indoor environment problems in buildings

Hart-Schubert, Patrice 07 October 2005 (has links)
The efficacy of indoor environment evaluation is, in part, a function of the reliability and validity of the different measures used. This thesis presents results of a study, conducted in a building without known problems, which compares the reliability and validity of sensory comfort components from three well-known survey questionnaires. A review of literature reveals that sensory comfort theory draws upon many disciplines including, hedonics, psychometrics, and olfaction theory. The fundamental domains thermal, air quality, lighting, and acoustics and their dimensions are identified. The conceptual model integrates these theories underlying human response to sensory comfort. The research questions involved in the selection of survey questionnaires are explored by examining sixteen indoor environment survey questionnaires. A meta-evaluation reveals that these questionnaires have three major functions, proactive, reactive, and re-evaluative studies. Finally, the methods used to analyze survey questionnaires for reliability and validity are examined. An analysis of variance shows that the order in which questions were presented did not affect responses. The reliability of the measures tested ranged from poor to good. Examination of content and face validity by expert and untrained judges demonstrates inconsistencies in common or accepted meanings of the measures considered in evaluating the indoor environment. Analysis of construct validity indicates that not all survey questionnaire variables were categorized under their expected dimensions. Contrary to advice found in the literature, this thesis suggests that the practice of combining items from different questionnaires is problematic. Finally, in buildings with known problems we can expect a relatively high degree of reliability and validity. However, the utility of such questionnaires in inventorying and assessing buildings without known problems will prove to be questionable. / Master of Urban and Regional Planning
414

Effects of holding tank odor control chemicals on aerobic wastewater treatment

McDaniel, Charles Russell 08 September 2012 (has links)
Three odor control chemicals and formaldehyde were tested for detrimental affects on activated sludge using bench-scale bioreactors. Slug fed and continuous flow bioreactors were monitored for changes in suspended solids, specific oxygen uptake rate, sludge settling and compaction, and effluent COD. The biodegradability of dyes and the generation of foam was also measured. Formaldehyde and the formaldehyde-based odor control chemical "Aqua-Kem" damaged the ability of activated sludge to treat wastewater. They resulted in deceased suspended solids concentrations and increased effluent COD. Formaldehyde hinders the utilization of normal wastewater substrate by activated sludge. The dye in "Aqua-Kem" is not biodegradable, and surfactants in the chemical generate foam. / Master of Science
415

The synthesis of 10-(4-hydroxymethylphenyl)-1,2-Benzanthracene

Lewis, Claude Irenius January 1959 (has links)
A. The alcohol, 10-(4’-hydroxymethylphenyl)-1,2-benzanthracene, was prepared by the reduction or 10-(4’-carboxyphenyl)- 1,2- benzanthracene. The structure or the alcohol was proven by: (1) Ultraviolet spectra (2) Infrared spectra (3) Elementary analysis (4) Preparation or the benzoate B. The preparation of the Grignard reagent of 10-(4’-bromophenyl)-1,2-benzanthracene was unsuccessful. An explanation of this anomaly was not discovered. C. The Grignard reagent or 2-(1-naphthylmethyl)-chloro-benzene was prepared by the use or tetrahydrofuran and "entrainment" with methyl iodide. / M.S.
416

CRT anti-glare treatments, image quality, and human performance

Hunter, Marc W. January 1988 (has links)
This dissertation was a two-phase effort. Phase I investigated the physical image quality of 16 mesh, etched, and quarterwave antireflection filters for varying levels of filter transmissivity. Three levels of ambient lighting and two levels of monochrome CRT resolution were combined factorially with the filters. In addition, user measures of readability, legibility, and perceived image quality were obtained for these same filter and environmental conditions. Quantitative models were developed to predict the performance and subjective data based on signal and noise measures derived from the physical measurements. Phase II examined the effects of a wide range of filter transmissions and diffuse illuminance on measured image quality and the same user measures as in Phase I. Phase I showed that while none of the glare filters yielded improved readability or legibility over a baseline condition, the etched and low transmission filters were notable for their degradation of human performance. Mesh and quarterwave filters were found to improve perceived image quality when a specular glare source was present. Modeling was minimally successful for the reading and legibility tasks, but yielded good fit models for perceived image quality. Phase II showed that when even extreme losses in display contrast occurred, users were capable of good reading and legibility performance. Perceived image quality was inversely related to illuminance level. Prediction of performance by image quality metrics was generally not too successful. It was concluded that in office-type environments, mesh or quarterwave filters can be used to improve perceived image quality when specular glare sources are present, but that no anti-glare filters yielded enhanced short-term readability or legibility over a baseline. Etched filters were not recommended. Measures of physical image quality proved to be good predictors of perceived image quality, but not of timed measures of readability or legibility. Under moderate lighting conditions, monochrome CRTs should be fitted with fairly high transmission filters as it was found the contrast enhancement offered by low transmission filters had negligible effects on performance. Finally, consistent and repeatable findings of degraded legibility for high luminance contrast levels (low illuminance) generated questions as to the existing standards regarding maximum contrast requirements for CRT use. / Ph. D.
417

The effects of moderate exercise on dietary intake, iron status, and cardiovascular endurance of 56- to 67-year-old women

Woo, Violet Ryo-Hwa 12 March 2009 (has links)
The purpose of this study was to determine the effects of moderate exercise on iron status, dietary intake and cardiovascular fitness in 56- to 67-year-old women. Women 56- to 67-years-old were randomly assigned to two groups: exercise (n=8) or non-exercise (n=9) groups. Women in the exercise group cycled on an ergometer three days/week, 30 minutes/session at 70-75% maximal heart rate for 10 consecutive weeks. At weeks 0 and 11, submaximal treadmill stress tests were obtained to determine cardiovascular fitness level. Venous blood samples were also obtained at weeks 0 and 11 to determine serum ferritin, transferrin saturation, serum iron, total iron-binding capacity, hematocrit and hemoglobin concentrations. Three-day dietary and activity records were obtained from each subject at weeks 0 and 10. Using paired t-tests for statistical analysis, the data indicated a significant increase in time to reach 70% maximum heart rate (p<0.001), a significant decrease in average heart rate/grade (p<0.05) and a significant increase in hemoglobin concentrations (p<0.01) in the exercise group at week 11. Student t-tests indicated significant differences between the groups in hemoglobin concentration at week 0 (p<0.005) and hematocrit concentration at weeks 0 and 11 (p<0.05). The exercise group had significantly lower vitamin C and monounsaturated fatty acid intake than the non-exercise group at week 0 (p<0.05). No other significant differences in nutrient intakes were observed between or within the two groups. Caloric intakes varied widely between the two groups, ranging from 1223.0 ± 248.4 to 1533.3 ± 480.8 kcal at weeks 0 and 10 in the exercise group; 1270.1 ± 376.3 to 1348.7 ± 334.8 kcal in the non-exercise group. Intakes of zinc were less than 70% of the 1989 RDA in both groups, ranging from 56.9 ± 14.6 to 66.6 ± 16.3 percent. The results indicate that moderate exercise does not significantly change the dietary intake and all parameters of iron status but enhances the cardiovascular fitness level in 56- to 67-year-old women. / Master of Science
418

Health Disparities in Timely Goals of Care Discussions and Hospitalizations Due to Infections in Nursing Home Residents

Kang, Jung A. January 2024 (has links)
This dissertation investigates the effectiveness of and disparities in timely goals of care (TGOC) discussions in nursing homes (NHs), as well as hospitalizations due to infections. Chapter One provided an overview of the dissertation, including its aims and conceptual frameworks. Chapter Two is a systematic review of the current evidence concerning the timing of goals of care discussions in NHs and their impact on end-of-life outcomes. Chapter Three examines the differences in TGOC discussions in NHs for Black. Chapter Four analyzes the association between TGOC discussions and hospitalizations due to infections. Finally, Chapter Five synthesizes all findings. Key findings demonstrate that while effective TGOC discussions are associated with reduced hospitalizations due to infections in NH residents, significant racial and ethnic disparities exist, particularly among NHs with higher proportions of Black residents and those located in socioeconomically disadvantaged areas. These findings highlight the need for improved TGOC practices and targeted interventions to address systemic barriers and ensure equitable end-of-life care.
419

Environmental health management of Trinidad carnival : challenges and implications for cultural tourism development

Bedeau, Koren 01 October 2003 (has links)
No description available.
420

Hygiene and nutritional content of the National School Nutrition Programme in Bloemfontein, South Africa

Nhlapo, Nthabiseng January 2013 (has links)
Thesis (M. Tech. (Environmental Health)) -- Central University of technology, Free State, 2013 / Malnutrition and concomitant infections are major contributing factors to child morbidity and mortality in developing countries such as South Africa. Globally, children benefiting from school feeding programmes are generally from communities with low socio-economic statuses. The meals provided through feeding schemes, such as the National School Nutrition Programme (NSNP) in South Africa, are aimed at significantly supplementing the beneficiaries’ daily energy and nutrient requirements. The possible nutrient deficiency of meals provided through such programmes compromises the nutritional well-being of children, promotes malnutrition and renders children more susceptible to infectious diseases. Furthermore, illness, particularly caused by diarrhoeal and infectious diseases, is a major factor contributing to child malnutrition as the human body is unable to efficiently digest foods and absorb nutrients during illness. Therefore, the microbiological safety of the foods served to children via feeding schemes is essential. In an effort to contribute towards the safety and wholesomeness of foodstuffs served through the NSNP, the present study was conducted with a view to assess the nutritional quality and safety of the foodstuffs. The knowledge, attitudes and practises (KAP) of food handlers and NSNP representatives/committee members at the schools were also investigated in order to assess origins of potential food contamination. Data collected via nutritional analyses of meals served to school children were compared to the nutrient-based standards set by the United Kingdom as guidelines for an average school lunch. The carbohydrate, energy, calcium and zinc contents of the school meals were below the standards, the majority of the meals met the protein and iron standards and all meals complied with the standards for lipid and vitamin C contents. During the microbiological analysis study, preparation surfaces yielded higher counts of all detected organisms (total coliforms, Escherichia coli, Staphylococcus aureus and yeasts and moulds) compared to the hands of food handlers. Therefore possible sources of contamination may be foodstuffs, animal pests and environmental elements such as dust. However, significant differences of surface microbial counts could not be established (P > 0.05) and thus cross-contamination may have resulted among surfaces, possibly augmented by shortfalls in cleaning regimes. The majority of the participants of the questionnaire survey reportedly washed their hands and cleaned all surfaces several times during the day with water and detergent. In addition, a disinfectant was used by some of the food preparers during cleaning. Furthermore, participants stated that their aprons were washed daily. These claims were in agreement with the findings of the surface microbial study with regards to the hands, however, they did not match the findings of the preparation surfaces which contained the highest counts of total coliforms, E. coli and S. aureus of the three surfaces analysed, and aprons responsible for the highest yeast and mould counts. Improper storage and food preparation methods, such as the application of high temperatures, excessive exposure to UV light and oxygen, and high moisture conditions, may result in the deterioration of nutrients. Storage conditions which may permit pest infestation may also increase the risk of food-related illnesses and risk could be further elevated by application of improper cleaning and sanitation practices. In order for the NSNP to operate effectively, it is essential that the national and provincial Departments of Basic Education, which are responsible for the overall administration of the NSNP, and schools’ personnel function in an integrated manner through support structures and effective communication. Infrastructural limitations (lack of proper kitchen facilities and ventilation) and shortage of resources while administering the NSNP were the main challenges observed during the present study. Due to these hurdles, adhering to food safety practices and maintaining nutritional quality of foods may be a challenge. Continuous training in personal and general hygiene is also a necessity in preserving food safety. Furthermore, nutritional quality of foodstuffs may be preserved through proper storage practices and application of preparation methods which minimize loss of nutrients.

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