Call number: LD2668 .T4 1979 M37 / Master of Science

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

published_or_final_version / Community Medicine / Doctoral / Doctor of Philosophy

Movies, songs, conferences, video streams and other multimedia services are spreading in everybody’s life, needs and work. Different types of audio and video codecs of various qualities appear to be used for different purposes. However, each codec can be suitable for a special usage, as for example a codec that can be use for high quality film may not be suitable for streaming it into network. The main purpose of this thesis is to compare the performance of different codecs in one particular scenario and indicate which codec performance is the best. The thesis work includes the investigation of several codec aspects (audio and video) and problems related to choosing a multimedia codec (coder/decoder) suitable for large-scale multimedia distribution over the Internet. More specifically, the work focuses on various features of modern media codecs, compares them and finds the best application for each of them. Furthermore, the thesis provides an overview of available research results related to this work and codec comparison tables for codecs and their features. Additionally, as part of this work, a testbed was developed to measure the performance of codecs when used to stream media over a network. The testbed enabled the collection of various QoS parameters, such as bandwidth usage and burst, size for each codec considered in this thesis. / Address: Minervavägen 22A, Room 2, 371 41 Karlskrona, sweden. Cel: +46706456674

A four-chamber indirect calorimeter was constructed to evaluate energy utilization by laying hens as affected by dietary energy, protein and amino acid levels and by housing temperature. Heat production was measured by indirect calorimetry and metabolizable energy was determined for each diet. Net energetic efficiency was calculated as the slope of the regression of energy balance (metabolizable energy intake - heat production) on metabolizable energy intake. Hens fed diets formulated without protein specifications to provide amino acid levels equivalent to those provided by 14.5 or 16% protein, had higher (P < .05) net energetic efficiencies than hens fed diets formulated with specified protein levels. Addition of 3% animal fat to the higher (16% protein) amino acid diets produced the greatest increases (P < .05) in net efficiency, but decreased (P < .05) efficiency in the lower (14.5% protein) amino acid diet formulated without a protein specification. Metabolizable energy available for production was improved (P < .05) with animal fat additions to all but the diet formulated to the higher (16% protein) amino acid levels. Animal fat, cottonseed oil, corn oil, cod liver oil and safflower oil were used to determine effects of fat source on energy utilization by laying hens at 21.1 C. Higher net efficiencies were obtained for the cottonseed and safflower oil diets (99.1 and 99.8%, respectively) than for the basal diet (90.6%) or the other fat sources (cod liver oil = 86.0%, corn oil = 87.3%, animal fat = 91.1%). Full vs. meal (two 1-hr periods daily) feeding and total sulfur amino acid deficiency effects on energy utilization were evaluated. Meal feeding reduced (P < .05) metabolizable energy available for production while increasing (P < .05) maintenance metabolizable energy requirements. Feeding regime did not reverse the decline (P < .05) in net efficiency (89.2-89.7 to 81.7-82.6%) observed with total sulfur amino acid deficiency. Hens were fed either 7% animal fat or 7% corn oil and maintained at 10, 21.1 and 32.2 C to study effects of fat source and temperature on energy utilization. From 10 to 32.2 C, net energetic efficiency increased from 87.6 to 92.6% with animal fat. Corn oil showed the highest net efficiency (93.9%) at 10 C, while animal fat was highest (92.6%) at 32.2 C. Hens fed animal fat required the most (P < .05) maintenance metabolizable energy and had the highest (P < .05) fasting heat productions at each temperature.

Ultra-wideband (UWB) communications has emerged as a promising technology for high data rate wireless personal area networks (WPANs). Several proposals for UWB-based WPANs have been made. One widely popular proposal is based on multi-channel OFDM. This proposal was recently standardized by European Computer Manufacturers Association (ECMA). In this dissertation, we address several important aspects that impact the performance of OFDM-based UWB systems. First, we propose an interference management distributed reservation protocol (IMDRP) for these communications. IM-DRP aims at reducing interference between uncooperative beacon groups that operate simultaneously over the same area. We then integrate IM-DRP into the design of a rate adaptation strategy that exploits the multi-rate capability of OFDM-based UWB systems. Besides maintaining a target packet error rate, our proposed strategy attempts to reduce the required reservation time over a link, hence allowing more links to be concurrently activated. Second, we propose a novel overhearing-aware joint routing and rate selection (ORRS) scheme. For a given source-destination pair, ORRS aims at selecting a path and its transmission rates that achieve the minimum channel reservation time, leading to low blocking rate for prospective reservations and high network throughput. At the same time, ORRS takes advantage of packet overhearing, a typical characteristic of broadcast communications. Finally, we propose a novel resource utilization mechanism (RUM) for improving the throughput in multi-rate UWB-based WPANs. RUM exploits opportunistic-relaying and time-spreading techniques to improve link reliability and increase the transmission rate, and hence network throughput. Simulation results indicate that our proposed protocols and schemes achieve significant throughput improvement compared with other protocols.

The objectives of this study were to investigate the hypotheses that: (1) Job satisfaction is related to medical specialty, the physician's nationality, and length of tenure. (2) The physician's attitude toward the Drug Utilization Review (DUR) program is related to medical specialty, the place of residency training, length of tenure, and job satisfaction. (3) The quality of drug prescribing is related to medical specialty, the place of residency training, length of tenure, job satisfaction, and the physician's attitude toward the DUR program. The results indicated a significant relationship between the physician's nationality and job satisfaction (P = 0.001), and between job satisfaction and the physician's attitude toward the DUR program (P 0.001). Medical specialty was a strong independent predictor of the quality of drug prescribing (P = 0.002). However, the other independent variables of the locale of residency training, length of tenure, job satisfaction, and the physician's attitude toward the DUR program were not related to drug prescribing.

A nursing concern for patients with chronic obstructive airway disease (COAD) is to assist the patient/family in improving adaptation strategies and self-care abilities. Identification of emotional and behavioral characteristics impacting on symptoms and life quality may predict individuals at risk for greater utilization of health care resources. The purpose of this descriptive study was to apply Traver's Prediction Formula for Emergent Use to a more general COAD population to determine if the formula would accurately predict those subjects who have high versus low emergent use of institutional health care resources. Fifty subjects with a range of COAD severity were studied. Subjects completed instruments which measured symptoms and life quality: the Bronchitis-Emphysema Symptom Checklist and the Sickness-Impact Profile. Findings demonstrated Traver's Formula predicted low emergent subjects with 76 percent accuracy, high emergent subjects with 53 percent accuracy and predicted the overall emergent status of subjects with 67 percent accuracy.

This study was undertaken to assess factors contributing to difference in nutritional status of patients at high risk for malnutrition. Twenty-five patients hospitalized for treatment of cancer and other disorders and for surgery were assessed using anthropometric, biochemical and dietary measures.Significant malnutrition was found. Males, as compared with females, had lower percent triceps skinfold, percent weight-for-height, percent hemoglobin, decreased appetites and total iron binding capacity. Mean total iron binding capacity for males was 62 percent of normal suggesting acute malnutrition similar to kwashiorkor. Cancer patients had lower total lymphocyte counts than those with other diagnosis. Patients hospitalized more than 23 days showed evidence of marasmus, with lower percent mid-arm muscle circumference, percent hematocrit, percent hemoglobin and a tendency for decreased weight/height than those hospitalized for a short time. Compared with patients with good appetites, those experiencing poor appetites had increased caloric and protein needs but lower protein intake compared to needs and lower creatinine-height-index.Five subjects with decreased weight/height had lower total iron binding capacity. The mean was 61 percent of normal indication severe depletion. The mid-arm muscle circumference was 82 percent of normal suggesting acute malnutrition imposed upon compromised somatic protein stores. Nine subjects showed evidence of frank kwashiorkor, three other subjects experienced marasmic-kwashiokor indication acute malnutrition imposed upon chronic malnutrition.In conclusion, this study suggests several characteristic features of hospitalized patients at risk for malnutrition: hospitalization for over three weeks, inadequate caloric and protein intake relation to need and anorexia. These patients are candidates for nutritional assessment and support.

The purpose of this investigation is to attempt to learn something of the biochemical ecology of volatile substances produced by actinomycetes.