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Full-Text Articles in Life Sciences

Gregarious Behavior In Large Mammals: Modeling, Methodology, And Application, Thomas L. Morton May 1993

Gregarious Behavior In Large Mammals: Modeling, Methodology, And Application, Thomas L. Morton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Gregarious behavior of ungulates was considered in four ways. The first concern was W. D. Hamilton's hypothesis that a simple movement rule could reduce predation risk and encourage grouping behavior. Simulations showed little effect of this nearest-neighbor rule on predation risk. Similar, more complicated rules reduced predation risk by up to two thirds.

The second focus was on the accuracy of ground observers in diagramming individual animal locations in small herds of elk. A remotely controlled airplane was used to photograph the herds from above. A substantial distance discrepancy was found between "true" and "observed" animal locations. This discrepancy increased …


Effects Of Elevated Co2 On Crop Growth Rates, Radiation Absorption, Canopy Quantum Yield, Canopy Carbon Use Efficiency, And Root Respiration Of Wheat, Oscar A. Monje May 1993

Effects Of Elevated Co2 On Crop Growth Rates, Radiation Absorption, Canopy Quantum Yield, Canopy Carbon Use Efficiency, And Root Respiration Of Wheat, Oscar A. Monje

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat canopies were grown at either 330 or 1200 μmol mol-1 CO2 in sealed controlled environments, where carbon fluxes and radiation interception were continuously and nondestructively measured during their life cycles. The effects of elevated CO2 on daily growth rates, canopy quantum yield, canopy and root carbon use efficiencies, and final dry mass were calculated from carbon flux measurements in an open gas exchange system. Dry biomass at harvest was predicted from the gas exchange data to within ± 8%. The greatest effect of elevated CO2 occurred in the first 15d after emergence; however, several physiological …


Resource Partitioning Among Brown Bears At Brooks River In Katmai National Park And Preserve, Alaska, Tamara L. Olson May 1993

Resource Partitioning Among Brown Bears At Brooks River In Katmai National Park And Preserve, Alaska, Tamara L. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A quantitative study of the behavior of brown bears (Ursus arctos) was undertaken in areas of different human activity at Brooks River in Katmai National Park and Preserve, 1988-1990. The research was conducted to determine whether the activity of any particular classes of bears using the river were differentially affected by human activity, activity of conspecifics, or availability of salmon. Approximately 1643 hours of systematic observation were recorded, 781 between June 26 and July 29 and 862 hours between August 26 and October 12 of all three years. Comparisons of fish capture rates by bears and distributions of …


Characterization Of A Dexamethasone-Immunosuppressed C57bl/6n Mouse Model For Chronic Cryptosporidiosis, Edward G. Martin May 1993

Characterization Of A Dexamethasone-Immunosuppressed C57bl/6n Mouse Model For Chronic Cryptosporidiosis, Edward G. Martin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cryptosporidium parvum is a coccidian protozoan that colonizes epithelial cells lining respiratory and digestive tracts of animals and humans. Cryptosporidiosis is a well-recognized zoonotic disease infecting primarily neonates and immunocompromised hosts, including human immunodeficiency virus-infected patients. Clinical disease is manifested as a chronic diarrheal illness that is self-limiting in immunocompetent hosts and prolonged and often life-threatening in hosts with compromised immune systems. The lack of a suitable small animal model for screening anti-cryptosporidial drugs and for examining the pathogenicity and immunobiology of chronic cryptosporidosis was the impetus for this research effort.

The objectives of the present study were three-fold: to …


Effects Of Rumen-Protected Amino Acids On Production In Holstein Cows, David Paul Dawson May 1993

Effects Of Rumen-Protected Amino Acids On Production In Holstein Cows, David Paul Dawson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Six nonlactating Holstein cows fitted with rumen and duodenal cannula were used to determine the efficacy of pH sensitive fatty acid polymer encapsulation as a means protecting amino acids from rumen fermentation and as a post-ruminal amino acid delivery system. The cows were arranged in a 2 X 2 factorial in a Latin Square design. Treatments were 1) the basal ration, and 2) basal ration plus rumen-protected lysine, methionine, and threonine at 10 g each per day.

Rumen parameters measured were pH, ammonia, volatile fatty acids, protozoa, liquid, and dry matter rate of passage, total viable bacteria, and viable cellulolytic …


Treatment Of Low Quality Forages By Hydrogen Peroxide And(Or) Anhydrous Ammonia And Their Utilization In Ruminant Nutrition, Mohammed Diouri May 1993

Treatment Of Low Quality Forages By Hydrogen Peroxide And(Or) Anhydrous Ammonia And Their Utilization In Ruminant Nutrition, Mohammed Diouri

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three experiments were conducted to evaluate low quality forages treatment by anhydrous ammonia (NH3) and(or) hydrogen peroxide (H2O2).

In experiment I, a control and three treatments of barley straw were compared: NH3, NH3 after rehydration of the straw with water (NH3+H2O), and NH3 after rehydration with a H2O2 solution (NH3+H2O2). Forages were fed, with a supplement, at two levels of intake (ad libitum and 75% of ad lib.). Treatments were administered in a split-plot in a Latin …


Effect Of Salinity (Nacl) On Germination, Growth, Ion Accumulation, And Protein Synthesis In Alfalfa (Medicago Sativa L.), Thamir S. Al-Niemi May 1993

Effect Of Salinity (Nacl) On Germination, Growth, Ion Accumulation, And Protein Synthesis In Alfalfa (Medicago Sativa L.), Thamir S. Al-Niemi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

To study the effect of NaCl stress on gene expression in alfalfa (Medicago sativa L.), greenhouse and laboratory experiments were conducted with 22 cultivars during germination and post-germination growth. The ability of alfalfa cultivars to germinate at the different NaCl concentrations was not related to their postgermination performance (salt tolerance) under those conditions.

Genetic effects were evident for Na and Cl ion uptake and accumulation in alfalfa shoots and roots. The strategies of alfalfa cultivars to cope with NaCl stress includes exclusion of Na from shoots and Cl from roots or from the whole plant depending on cultivar and …


Fat Content Of American Kestrels (Falco Sparverius) And Sharp-Shinned Hawks (Accipiter Striatus) Estimated By Total Body Electrical Conductivity, Shari M. Harden May 1993

Fat Content Of American Kestrels (Falco Sparverius) And Sharp-Shinned Hawks (Accipiter Striatus) Estimated By Total Body Electrical Conductivity, Shari M. Harden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Total body electrical conductivity (TOBEC) is a noninvasive method for the estimation of lean mass in live subjects. Lipid content can be calculated from the body mass measured and the lean mass estimated from TOBEC. I used live American Kestrels (Falco sparverius) to study the accuracy of this method. TOBEC measurements were compared to actual body content determined by Soxhlet fat extraction using petroleum ether as the solvent. TOBEC estimated 73.7% of the variation in lean mass in a sample of 21 kestrels. The use of restraining devices (Vetrap and cardboard cylinders) altered the TOBEC measurement but only …


Influence Of Microphytic Crusts On Selected Soil Physical And Hydrologic Properties In The Hartnet Draw, Capitol Reef National Park, Utah., John Dana Williams May 1993

Influence Of Microphytic Crusts On Selected Soil Physical And Hydrologic Properties In The Hartnet Draw, Capitol Reef National Park, Utah., John Dana Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microphytic crust influences on selected physical and hydrologic soil properties were examined at one location in Capitol Reef National Park, Utah. Designed experiments were conducted in a sandy loam soil where microphytic crusts were present without the concomitant development of confounding physical or chemical soil conditions. Three treatments were used for all experiments: control, chemically killed (microphytes killed but left in place), and scalped (microphytic crusts mechanically removed).

A portable wind tunnel was used to deter-nine if microphytic crusts contribute to soil stability and reduce the erosive effect of wind. Significantly lower threshold friction velocity and greater wind-entrained material were …


Anaerobic Treatment Of Whey Permeate Using Upflow Sludge Blanket Bioreactors, Seokhwan Hwang May 1993

Anaerobic Treatment Of Whey Permeate Using Upflow Sludge Blanket Bioreactors, Seokhwan Hwang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Whey permeate was anaerobically digested in laboratory scale upflow anaerobic sludge blanket reactors. Nine hydraulic retention times between 5 and 0.2 days were examined with a fixed influent concentration of 10.6 ± 0.2 g COD/L.

Chemical oxygen demand removal efficiency ranged from 99.0 to 18.9% and maximum production rate of methane gas was 2.67 L/L/day at a hydraulic loading rate of 12.97 kg COD/m3/day. About 70% of the chemical oxygen demand removed was converted to methane.

Both the nonlinear least square method with 95% confidence interval and linear regression were used to evaluate kinetic coefficients. The maximum substrate …


The Impact Of Nutrition Education On Dietary Behavior And Iron Status In Participants Of The Supplemental Food Program For Women, Infants And Children, And The Expanded Food And Nutrition Education Program, Nedra K. Christensen May 1993

The Impact Of Nutrition Education On Dietary Behavior And Iron Status In Participants Of The Supplemental Food Program For Women, Infants And Children, And The Expanded Food And Nutrition Education Program, Nedra K. Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was conducted to determine the impact of nutrition education on participants of the Supplemental Food Program for Women, Infants and Children (WIC) and the Expanded Food and Nutrition Education Program (EFNEP). The specific objectives were to: 1) determine the impact of participation in EFNEP on iron status as assessed by hematocrit (hct) and ferritin levels; 2) determine the effect of nutrition knowledge on hct and ferritin values; and 3) determine the effect dietary behavior has on hct and ferritin levels for both WIC and EFNEP participants.

Each study participant completed a 24-hour dietary recall record plus food frequency …


Influence Of The Ruminant Digestive Process On The Germinability Of Range Forage Species, Mohammed S. Al-Mashikhi May 1993

Influence Of The Ruminant Digestive Process On The Germinability Of Range Forage Species, Mohammed S. Al-Mashikhi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ingestion and dispersal of seeds of desirable species by domestic livestock is potentially important as a range improvement practice, but the passage of seed by livestock has only been studied in a fragmented way, particularly for species adapted to rangelands of western North America. The objectives of this research were to examine the effects of different periods of exposure to in vitro and in vivo digestion processes in cattle on the germinability of several grass species, and determine if the in vitro incubation technique is a good predictor of seed fate following passage through the ruminant digestive tract.

Seeds of …


Competitive Interaction Between Crested Wheatgrasses And Cheatgrass, Mark G. Francis May 1993

Competitive Interaction Between Crested Wheatgrasses And Cheatgrass, Mark G. Francis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Current revegetation practices in the lntermountain West include the use of Nordan (Agropyron desertorum) and Hycrest (A. cristatum x desertorum) crested wheatgrass on rangeland susceptible to cheatgrass (Bromus tectorum) invasion, although little quantitative data exists that compares their competitive abilities. We evaluated both the competitive ability of Hycrest and Nordan in two-species mixtures with cheatgrass, and evaluated seedling establishment characteristics for all three species in a greenhouse study. Linear and nonlinear models were developed for a range of densities for each species to predict median above-ground biomass and tiller numbers. In both experiments, increasing …


Effects Of Water Stress Preconditioning On Plant Water Relations And Transplant Survival Of Artemisia Cana And Agropyron Intermedium, Jerriann Ernstsen May 1993

Effects Of Water Stress Preconditioning On Plant Water Relations And Transplant Survival Of Artemisia Cana And Agropyron Intermedium, Jerriann Ernstsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Typically, dormant seedlings are transplanted when revegetating nonirrigated disturbed lands in order to prevent transplant shock triggered by water stress. Since dormant seedlings have to be used, this limits the duration of the transplant season. It may be possible to increase this limited season by inducing acclimation responses that would increase drought tolerance. Preconditioning actively growing seedlings to water stress prior to transplanting could induce acclimation responses such as solute accumulation and/or stomatal modulation.

Under greenhouse conditions, A. cana and A. intermedium seedlings were subjected to three water stress preconditioning treatments: a well watered control, one dry-down cycle, and three …


Postbreeding Ecology Of Adult Male Northern Pintails And Cinnamon Teal Near Great Salt Lake, Utah, Robert R. Cox Jr. May 1993

Postbreeding Ecology Of Adult Male Northern Pintails And Cinnamon Teal Near Great Salt Lake, Utah, Robert R. Cox Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I studied nutrient reserves, digestive organs, molt intensity, diets, and seasonal changes in food resources available to postbreeding adult male Northern Pintails (Anas acuta) and Cinnamon Teal (Anas cyanoptera) in marshes near Great Salt Lake, Utah. Total lipid and protein reserves of Northern Pintails were lower during the flightless period than before or after. For Cinnamon Teal, total protein was lowest during the flightless period, and total lipid showed a similar trend. Total mineral did not differ among plumage classes in either species. Use of nutrient reserves in these species may be an endogenous rhythm in …


A Study Of Factors Controlling Physical Properties Of Mozzarella Cheese And The Manufacture Of A Reduced Fat Mozzarella Cheese, Richard Kevin Merrill May 1993

A Study Of Factors Controlling Physical Properties Of Mozzarella Cheese And The Manufacture Of A Reduced Fat Mozzarella Cheese, Richard Kevin Merrill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Variables affecting the physical properties of Mozzarella cheese were investigated. The effects of various milk-clotting enzymes were examined. The type of milk coagulating enzyme used played a significant role in determining physical properties of direct acid Mozzarella cheese. Cook color was not affected by enzyme type, but melt and stretch were significantly affected.

Proteolytic nature of starter cultures was reviewed and recommendation s were give n. Cheese made with proteinase-deficient strains had more stretch after holding for 14 and 28 d than cheese made with non-deficient strains. Cheese made with pairs or single strains of L. helveticus had the same …


Sensory And Functional Properties Of Wheat Stored Under Home Conditions, Marilyn M. Shumway May 1993

Sensory And Functional Properties Of Wheat Stored Under Home Conditions, Marilyn M. Shumway

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Samples of wheat that had been stored in homes up to 48 years were collected with information about age and storage conditions. Germination, weight per bushel, protein, moisture, grade, and aroma were investigated. Volumes of gluten balls and bread made from ground whole wheat samples were measured. Sensory attributes of bread were evaluated by Quantitative Descriptive Analysis (QDA) for eight flavor and seven texture characteristics. Because of the tremendous variation in samples, generalizations on cause and effect are difficult to make. No one criterion was a perfect indicator of quality. A high percentage of germination was one of the better …


Formation Of Polycyclic Aromatic Hydrocarbons On The Surfaces Of Ultra-High Temperature Treated Meat, Michelle T. Foote May 1993

Formation Of Polycyclic Aromatic Hydrocarbons On The Surfaces Of Ultra-High Temperature Treated Meat, Michelle T. Foote

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of ultra-high temperature (UHT) on production of polycyclic aromatic hydrocarbons (PAHs) on the surface of beef steaks was determined. Beef steaks were treated with five treatments, raw, UHT, UHT/grill marks, UHT/grill marks/microwave, and charcoal grilled. Four PAHs, benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and benzo[k]fluoranthene, were quantified. High performance liquid chromatography (HPLC) and gas chromatography (GC) were used to purify and analyze the PAH extracts, respectively. Levels of PAH found on charcoal-grilled steaks were higher than those observed in the literature. A balanced incomplete block design was used to analyze the data. There were no significant differences among the treatments in …