Numerous properties of Yucca schidigera and Quillaja saponaria have been studied with respect to the saponins in the plant. These saponins are present in the extract as well and have been utilized commercially in the food and cosmetic industry for various products. Saponins have detergent-like properties in the presence of water. The detergent-like behavior of saponins plays a major role in their membranolytic properties. In addition, emulsification effects on fat which are characteristic of surfactant-type substances, may occur as well. Three studies were conducted using adult roosters, growing broiler chicks, and growing Japanese quail. Various effects of supplementing Yucca schidigera in the diets of these birds were studied such as: growth performance, overall health, and nutrient availability. An additional experiment was conducted comparing effects of Quillaja saponaria and Yucca schidigera extracts on body weight and fat digestibility in adult roosters. Addition of Yucca schidigera extract to high fat diets (tallow-based) increased lipid excretion in roosters, broilers, and quail. In roosters, dose of yucca extract affected excretion of lipid but no dose effects were seen in broilers or quail. Fat digestibility was not significantly affected by addition of saponins to the diet of adult roosters. However, fat digestibility was reduced in broilers and quail consuming a high fat diet. In general, level of dietary fat seemed to play a role in the effects of Yucca schidigera supplementation in growing birds. Addition of Yucca schidigera to high fat diets resulted in decreased plasma levels of vitamin A and E in broiler chicks. / Graduation date: 2000

The development of assays for stress in marine fishes is vital for studying the impacts of bycatch in fisheries and for determining the health of fish being cultured or used in research. This research developed behavioral and physiological assays for stress in juvenile sablefish, Anoplopoma fimbria, a species that comprises a valuable North Pacific fishery and is often a substantial part of incidental discard. The effects of conditions, intrinsic or extrinsic to the fish, on the variability of the stress response were also investigated. A moderate stress of 15 minutes in air was used to elicit an acute stress response. Behavioral responses and physiological values were evaluated at 1, 5, and 24 hours after the 15 minute air stress, and were compared with control fish that received only a minimal air stress. In the first series of experiments, behavioral patterns and changes in behavior over time of stressed and control fish were determined, and the protocols and time course for measuring behavioral effects of stress were established. In the second series of experiments, physiological assays were added to the behavioral protocols developed during the first series of experiments. The behavioral assays included activity levels, swimming speed at capture, and appetitive behavioral patterns in response to a chemical food stimulus (squid extract), and to a visual food stimulus (squid without odor). These behaviors are ecologically relevant in terms of performance and survival. All of these behaviors were sensitive to stress. In general, behavioral responses were depressed by stress at 1 hour, followed by recovery to control levels by 5 hours. However, the intensity of behavioral responses was affected by feeding history (1 or 5 days of food deprivation) and group influence (recovering alone or in visual contact with 3 conspecifics), which therefore affected the ability of the behavioral responses to assess stress. The behavioral assays were less capable of detecting differences between stressed and control fish when the responses of control fish were depressed as a consequence ofbeing fed the day before. Visual contact with conspecifics facilitated recovery of activity in stressed fish, but therefore also resulted in apparent activity responses to chemical food stimulus that were more likely attributable to activity increases of conspecifics than to appetitive behavior. The focus of attention of isolated fish on activity of conspecifics often interfered with visual detection of food. The physiological assays included plasma concentrations of cortisol, glucose, and lactate, all of which proved to be sensitive measures of stress in sablefish. These parameters were elevated by stress at 1 hour, followed by a decreasing trend to 5 and 24 hours. The physiological assays were affected by feeding history, and an effect of group influence was also indicated. Cortisol and lactate levels in stressed fish fed the day before recovered faster than for stressed fish that were deprived of food for 5 days. Glucose levels in stressed fish fed the day before were not elevated above controls. These results suggested an alleviating effect of feeding on the biochemical stress response. At 5 hours, cortisol and glucose were elevated above baseline levels in both solitary stressed fish and in stressed fish influenced by a group, but also for controls influenced by a group, suggesting an exacerbating effect of isolated fish being in visual contact with groups. There were critical cortisol, glucose and lactate thresholds (180 ng/ml, 140 mg/dl, and 175 mg/dl, respectively) above which no appetitive behavioral responses occurred. These clear demarcation levels are extremely valuable for linking behavioral and physiological responses. These results indicate that behavioral and physiological assays are sensitive indicators of stress in sablefish, although the magnitude, time courses, and correlation of responses may be affected by factors intrinsic and extrinsic to the fish that may vary before and during recovery. There was a correspondence between behavioral and physiological indications of stress shortly after the stressor had been removed and levels of stress were still severe. However, there was a temporal discrepancy after partial recovery had occurred, at which time recovery of physiological norms had not yet been established although behavioral responses had recovered. While behavioral patterns may readjust quickly, the persistence of an energetic load during recovery from stress, as indicated by continued physiological perturbations, may compromise ability to respond to additional stressors. / Graduation date: 2001

Exposure to moderately high levels of ionizing radiation (<20 Gy) has in some instances shown a hormetic effect in numerous vegetable-type crops. Past experiments performed in outdoor cultivars have shown a somewhat unpredictable increase in growth rate with a higher overall yield in a specified time when the seeds are exposed to ionizing radiation prior to germination. This experiment has attempted to eliminate potentially confounding variables in the growth of a legume utilizing an Environmental Protection Agency controlled green house. The experiment was a completely randomized block design with six blocks and seven treatment groups. Each treatment group of pinto beans (Phaseolus vulgaris L.) were exposed to ������Co radiation, given doses of 5-20 Gy, planted and grown for 40 days. Due to the symbiotic relationship with rhizobium bacteria within a seed, the expected result was a lowered nitrogen fixation capacity as bacteria concentration was reduced due to sterilization by the high energy gamma, yielding a smaller plant mass. The predicted trend in reduction would be described by the linear no-threshold model. A statistically significant increase in overall plant mass occurred in the 5 Gy treatment group, with a subsequent linear trend in mass reduction at treatment levels of 7.5, 10, 12.5 and 15 Gy. The overall quality and plant mass decreased markedly at a treatment level of 20 Gy. Additional possible contributions to plant differences in growth within a green house were light intensity, temperature, CO��� level and soil water retention. The complete randomized block design attempts to remove these as potentially confounding variables. / Graduation date: 1999

In an experimental field study, populations of gray-tailed voles (Microtus canicaudus) were exposed to a commercial formulation of vinclozolin, a fungicide effective for disease control on ornamental plants, turf grasses, and fruits and vegetables. Vinclozolin has been shown in laboratory experiments to behave as an androgen antagonist, impairing the reproductive development in males of several species of mammals when exposed in utero. However, when applied to grassland habitat containing populations of gray-tailed voles, no biologically significant impairment was observed in reproductive development of male voles whose mothers were exposed to the treatment while the young were in utero. Reproductive organs were sufficiently developed to result in high reproductive rates and juvenile recruitment in the field with no effects on population growth or demography. Under the conditions of this study, one standard application of Curalan[copyright] fungicide had no measurable reproductive or demographic consequences on gray-tailed voles. However, the results suggest that higher application rates or several successive applications may have negative impacts on reproductive development and demography of wild vole populations. / Graduation date: 1999

Graduation date: 1999

As Si MOS approaches its maximum limits in speed and bandwidth, new devices are desired to meet the needs of high speed communications and signal processing. A device that exhibits superior performance to Si MOS, BJT, and GaAs technology is the HEMT (high electron mobility transistor). The HEMT offers superior transconductance, mobility, speed, and noise performance compared to Si MOS, BJT, and standard GaAs technology. The high performance is a result of improved channel mobility due to a heterojunction. At the heterointerface, the majority carriers are confined to a very thin sheet forming what has been termed a 2DEG (two dimensional electron gas). The purpose of this thesis is to demonstrate the suitability of Honeywell's delta-doped self-aligned complimentary HIGFET process for the realization of high speed analog circuits. An operational amplifier and switched-capacitor circuit are presented. The operational amplifier has been fabricated at Honeywell and preliminary tests have been performed on the op-amp which are also presented. / Graduation date: 1998

Graduation date: 1997

Graduation date: 1997

Graduation date: 1996

Four experiments were carried out with broiler chicks from day-old to three or four weeks of age to assess the effects of nitrates and nitrites from calcium, potassium, and sodium salts in the drinking water of broilers on growth, body weights, feed utilization, blood chemistries, liver tissues, and lipid oxidation of breast and thigh tissues. Body weights were lower (P<.05) among chicks consuming calcium nitrate than those of chicks consuming sodium nitrate or the control. Chicks consuming calcium nitrate (Ca(NO���)���) at 1000 ppm had lower (P<.05) body weights than those drinking Ca(NO���)��� at 0, 50, or 200 ppm. Broilers receiving 1000 ppm of calcium nitrite (Ca(NO���)���) had depressed body weights when compared to chicks consuming 0, 50, or 200 ppm of Ca(NO���)���. Consumption of sodium nitrate (NaNO���) at 2033 ppm reduced (P<.05) broiler weights in comparison to broilers ingesting 0, 111, or 427 ppm of NaNO���. Feed utilization was less efficient (P<.05) by chicks ingesting Ca(NO���)��� and calcium, potassium, or sodium salts of nitrite when compared with the control. / Graduation date: 1996