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A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Information on livestock operations, particularly what kind of livestock operations are practiced in the Somali central rangelands, and how these operations differ for different herders in different vegetation types and farming systems, could serve as a major tool in making management decisions. This study provides a detailed description of range livestock operations in the Somali Central Rangelands. It also answers some important management questions.

Range livestock operations were inventoried through personal interviews with the owners and herders. Data are supplemented by previous nation-wide and regional survey statistics. Herd productivity data which include herd structures, age, age-related sales, slaughters, gifts, and …

The Effects Of Disease, Prey Fluctuation, And Clear-Cutting On American Marten In Newfoundland, Canada, Richard J. Fredrickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Individual variation in survival and behavior of American marten (Martes americana) was studied in relation to disease, prey fluctuation, and clear-cutting from 10 January 1986 through 20 August 1987 in Newfoundland, Canada. Thirty-seven of forty marten captured on the study area were telemetered and monitored for part or all of the study.

Marten mortality was concentrated in two intervals, fall 1986 and late winter 1987. Mortality during fall 1986 was attributable to encephalitis, while marten deaths during late winter 1987 resulted from predation and starvation attributable to the prey decline. Nonsuppurative encephalitis was first detected 7 October 1986; …

Substrate Concentration, Calcium Concentration And Κ-Casein Hydrolysis In Milk Coagulation, Fenjin He

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Milk coagulation consists of four overlapping phases: enzymic hydrolysis, micelle aggregation, gelation and syneresis. The objectives of this study were to determine the effects of added CaCl₂ on milk coagulation and the relationship between enzymic hydrolysis and micelle aggregation with substrate at different concentrations.

Addition of CaCl₂ to milk is widely practiced in industry and in laboratories. This changes calcium concentration, pH and ionic strength. It is impossible to separate these three variables and investigate each one independently.

Addition of low levels of CaCl₂ shortens coagulation time and increases curd firming rate. Low levels of CaCl_{2 …}

Irrigation Management Considering Soil Variability And Climatic Uncertainty, Dani Or

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The increase in multipurpose use of water resources, dwindling xii water supplies, and a decline in the economic viability of many agricultural operations make efficient irrigation management imperative. Soil variability and climatic uncertainty are major obstacles to efficient irrigation management due to a lack of reliable information for decision making. This study was aimed at identifying sources of uncertainty and examining methods for reducing the effects of uncertainty on irrigation scheduling schemes.

A method for spatial-temporal estimation that combines spatial information from few measurements with a physically based model of the system dynamics is proposed. The spatial phase of the …

Reaction Time In Elderly Subjects: The Effects Of Practice On Two Different Reaction Time Tasks, Dawn Marie Birk

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The reaction time of four groups of elderly human subjects were examined to determine the effects of stimulus presentation and task practice. Each group practiced different tasks, each requiring a response when more than one alternative was available. Two tasks involved making responses based on either visually or auditorily presented stimuli only. One task required decisions to be made on the basis of both auditory and visual stimuli. The fourth group acted as a comparison group and did not practice a reaction-time task; although they did perform a task on the computer and their reaction times were measured. Before and …

Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Root exploitation of enriched soil microsites was examined for the tussock grasses Agropyron desertorum and Agropyron spicatum and the shrub Artemisia tridentata. Two mechanisms of exploitation of the microsites were examined: root proliferation and changes in nutrient uptake capacity. One day after nutrient solution was applied to small soil patches, the mean relative growth rate of Agropyron desertorum roots in enriched patches was two to four times greater than for roots of the same plants in soil patches treated with distilled water. This rapid and striking root proliferation occurred in response to N-P-K enrichment as well as to P or …

Modeling Forest Dynamics Based On Stand Level Resource Allocation, Geoffrey Candler Poole

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An ecologically based model of forest succession is presented. In the model, trees compete for a share of limited growth resources available from their environment. Competition is reflected by each tree's effect on the resource pool and is not explicitly modeled. Model parameters were fit to field data from subalpine forests of the Rocky Mountains. A technique for estimating model parameters from understory-tolerance rankings and silvical characteristics of each species is also presented. The model's output was consistent with our current understanding of forest dynamics. Emergent properties of the model also mimicked natural processes such as self-thinning, release, and maximum …

Using Computer Imaging To Assess Visual Impacts Of Forest Insect And Disease Pests, Daniel Rabin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest insect and disease pests alter the appearance of trees, thereby impacting visual resources. Because of the complexity of most forest landscapes, the degree of visual impact of pest-infested forest stands is difficult to quantify.

This paper describes a method of measuring visual impacts of pest-infested forest stands. Photographs of healthy Ponderosa pine trees were entered into a computer video-image-processing system. Using this system, images of trees were altered to simulate different degrees of infestation by limb rust, a forest pathogen.

The altered and unaltered images were shown to groups of observers who rated the scenes in terms of "scenic …

Management, Foraging Behavior, Diet Composition And Forage Quality Of Free-Ranging But Herded Camels In Ceeldheer District, Central Somalia, Ahmed A. Elmi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In Somalia, camel (Camelus dromedarius) survivability and milk production has been higher than for other domestic livestock and contributes substantially to the subsistence of Somali pastoralists. The objective of this research was to study management, foraging behavior and nutrition of camels in their natural habitat to determine how production continues under seasonal nutritional stress.

Management systems of Ceeldheer pastoralists are based on available natural pasture and water. The natural rotation grazing system maintained an ecological equilibrium in the District.

Pastoralists manipulate their herds to suit existing environmental conditions, family needs and labor availability for herding. In herd management, …

The Effects Of A Direct Instruction Program In Fractions On Academic And Mathematics Self-Concept, William H. Lowry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The study investigated the effect of a videodisc-based, teacher-controlled, direct instruction-based program in fractions content, on self-concept. Self-concept was operationally defined as scores on a slightly modified version of Marsh's Self-Description Questionnaire (Marsh, 1988). A quasi-experimental, nonequivalent control group design was used to compare the self-report self-concept of two groups of upper elementary students (N = 337). The treatment group (n = 171) received instruction in fractions via the teacher-directed, videodisc-based, Mastering Fractions program (Systems Impact, 1986a). The control group (n = 166) received their normal grade four or grade five mathematics program, but did not include common fractions.

Differences …

Groundwater Flow Systems And Thermal Regimes Near Cooling Igneous Plutons: Influence Of Surface Topography, Mark U. Birch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Previous studies of cooling igneous plutons did not consider the possible influence of sloping surface topography. Topographically-driven fluids in high relief terrain, however, are thought to interact with deep buoyancy-driven fluids to produce large lateral-flow systems up to 5 km long and 20 km long in silicic and andesitic volcanic terrain, respectively. In this study, a quantitative investigation of the interaction of topographically-driven and buoyancy-driven fluid flow is conducted through the use of a finite element numerical model to simulate the fluid flow and thermal regimes associated with a cooling igneous pluton in the presence of significant topographic relief. The …

Chemical Evaluation And Biological Vitamin A Activity Of The Major Carotenoids In The Hybrid Carrot Beta Iii, Cynthia M. Schweitzer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Genetically enhanced high-carotene Beta III hybrid carrot was compared to a commercial carrot cultivar, Nantes Coreless, for carotene content and macronutrient composition. Beta III contained more than twice the total carotene content of Nantes Coreless, with α-carotene/β-carotene ratios higher in Beta III. Total solids from protein, lipids, and carbohydrate were greater in Beta III than in Nantes Coreless. Beta III contained about five times the amount of sucrose and one-fifth the amount of glucose and fructose than Nantes Coreless or reported literature values.

Comparison of the bioavailability of carotenes in Beta III and Nantes Coreless to purified β-carotene and retinyl …

Footwall Deformation And Structural Analysis Of The Footwall Of The Willard Thrust Fault, Northern Wasatch Range, Utah, Douglas Scott Neves

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Deformation mechanisms in the footwall of the Willard thrust fault, northern Wasatch Range, Utah, change from dominantly plastic to dominantly cataclastic (both microscopically and macroscopically) in the Ophir Formation and Maxfield Limestone before the thrust begins to ramp laterally upsection southward, just to the north of the North Ogden Canyon field area. This transition in compressional deformation style and mechanism is located within a lateral distance of 3.2-kilometers along the 22-kilometer long trace of the thrust fault.

Between Willard Canyon and North Ogden Canyon penetrative deformation is localized within 200 meters of the thrust surface and is characterized by transposed …

Origin And Evolution Of Dolostone In The Middle Cambrian Langston Formation, Northern Utah, Mark C. Hall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Six major generations of dolomite are present within the Cambrian Langston Formation in the Wellsville Mountains and Bear River Range of northern Utah. Identification of dolomite generations and delineation of their relative sequences are based on normal light petrography, cathodoluminescence, staining, chemistry, inferred burial history, and deformation features. The earliest stage is believed to be Middle to Late Cambrian in age. The presence of dolomite rhombs and dolomitized echinoid fragments and peloids suggests that this stage probably formed under sabkha reflux conditions. Extensive nonferroan, polymodal, nonplanar ("xenotopic") dolomite formed next under confined mixing zone conditions. A succeeding generation of pervasive …

Incremental Returns To Cattle Feeding From Alternative Feedlot Practices, Ibrahim R. Hani

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The main goals of this study are to: 1) identify the influence of various breeds, feeds, and hormone additives on the final weight or the rate of gain of feeder cattle; 2) determine the physical relationships among breeds, feeds, hormone additives, and other variables; and 3) estimate the costs and benefits associated with alternative feed and/or hormone additives and other variables to determine whether the benefits of using different breeds, feeds, and hormone additives exceed the costs. The linear mode l was initially chosen and showed that Rumensin additive and Angus and Simmental cross breeds were not significant on the …

An Assessment Of Thematic Mapper Satellite Data For Classifying Conifer Types In Northern Utah, Madeline R. Mazurski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Land-cover identification and mapping are an integral part of natural resource planning and management. Satellite imagery provides a way to obtain land cover information, particularly for large tracts of land such as those administered by federal and state agencies.

This study assesses the usefulness of the Brightness/Greenness Transformation of Landsat Thematic Mapper data for differentiating conifer forest types in northern Utah. Satellite data for the Logan Ranger District of the Wasatch-Cache National Forest were classified into 27 vegetation classes. Of these, nine were determined to be conifer classes and were used in subsequent analyses. Ten sites of each conifer class …

Density-Dependent Convective Flow In Closed Basins, Kim L. Mccleary

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Great Basin is a region of the Basin and Range Physiographic Province, which is completely isolated hydrologically from the sea. All precipitation that falls within the Great Basin is lost from the land surface or from the surface of closed inland lakes through evapotranspiration. Playas are often found at the base of these undrained basins. This study focuses on subsurface groundwater flow patterns in closed basins. Because all discharge from the basins occurs via evapotranspiration on and near the playa, the water table of the aquifer beneath the playa is often just below the ground surface. Fluctuations of the …

Probability Of Discrete Failures, Weibull Distribution, Mary Jo Hansen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The intent of this research and these is to describe the development of a series of charts and tables that provide the individual and cumulative probabilities of failure applying to the Weibull statistical distribution. The mathematical relationships are developed and the computer programs are described for deterministic and Monte Carlo models that compute and verify the results. Charts and tables reflecting the probabilities of failure for a selected set of parameters of the Weibull distribution functions are provided.

A Study Of Denitrosation Of N-Nitroso Compounds By Irradiation With Long-Wavelength Uv Light, Zhenyu J. Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

N-Nitrosamines and N-nitrosamides have been reported to be mutagenic. N-Nitrosamides are direct mutagens that need no activation to be mutagenic, whereas N-nitrosamines need to be enzymatically activated to exert their mutagenicity. Oxidative demethylation of nitrosamines is a commonly accepted activation mechanism. Another pathway of nitroso compounds, denitrosation, has recently been proposed. The mechanism of denitrosation, however, is still unknown.

The purpose of this study was to use a photo -reaction model to explore the possible denitrosation mechanism of N-nitroso compounds. An N-nitrosamine, N-nitrosomorpholi ne (NMOR), and an N-nitrosamide, N-methyl-N'-nitrosoguanidine (MMNG), were irradiated with long-wavelength UV light in the presence of …

Neuroanatomical Asymmetry, Handedness, And Family History Of Handedness: A Study Of The Markers Of Structural And Functional Lateralization, Steven A. Lifson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study investigated the associations between (1) handedness (demonstrated preference of one hand for the performance of most unimanual tasks) and neuroanatomical asymmetry (measurable differences in width between the cerebral hemispheres) and (2) familial history of handedness (the presence of a left-handed sibling or parent of a right-handed subject) as an intervening factor in the relation between handedness and neuroanatomical asymmetry. Width measurements of the brain were derived from computerized tomographic (CT) films and grouped in to categories by hand preference (measured by the Edinburgh Handedness Inventory) and family history. The measurements of right (n=68), right with left-handed relatives (n=24), …

An Apple Rest Model For Mild Winter Conditions, Jose Ignacio Del Real Laborde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two areas of research are reported: an experiment on the effects of warm temperature prestratification treatments on seed dormancy and a new chill unit model.

Crabapple seeds (Malus sargentii Rehd.) were allowed to imbibe water and were given warm pretreatments at temperatures of 16, 20, 24 and 28C for periods of 3, 10, 20 or 30 days before cold stratification at 4C for 20, 40, 60, 80 or 100 days. Pretreatments resulted in increased chilling requirements for seedling emergence. A short chilling period (20 days) also altered the leaf area, shoot length, internodal length and root/shoot ratio of the …

Soil Temperature Influence On Water Use And Yield Under Variable Irrigation, Jon M. Wraith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The need for efficient use of water resources has increased the importance of optimum soil water usage in agricultural systems. Soil temperature has been shown to be important in influencing the early development of many plant species. Many agricultural regions have suboptimal soil temperature regimes for plant growth, and some cultural practices have been shown to reduce near-surface soil temperatures. The seasonal influence of soil temperature on soil water extraction and aboveground and belowground plant growth under variable irrigation was investigated at the USU Greenville Farm in Logan, UT. Soil surface mulches and buried heat cables were used to modify …

Comparison Of Bootstrap With Other Tests For Several Distributions, Yu-Yu Wong

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper discusses results of a computer simulation to investigate several different tests when sampling several distributions. The hypothesis H₀: μ=0 was tested against H₀: μ≠0, using the usual t-test, trimmed t-test, the Jackkinfe, the Bootstrap and signed-rank test. The p-values and empirical power show that the Bootstrap is as good as the t-test. The Jackknife procedure is too liberal, always obtaining small p-values. The signed-rank is a fairly good test if the data follows the Cauchy Distribution.

Maternal, Obstetric, And Neonatal Correlates Of Short-Term Neurodevelopmental Outcome In Newborn Infants With Intraventricular Hemorrhage, Richard Elghammer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The attempt to identify risk factors or correlates of intraventricular hemorrhage (IVH) has been constrained by conflicting research findings, changing hypotheses about the etiology of IVH, and by the exceedingly complex nature of this neurological disorder. In addition, few studies have investigated the possibility that antenatal factors might predispose the infant to IVH. Thus, research aimed at identifying IVH correlates from all time periods in which stress could occur to the neonate needs to be undertaken. This study was conducted for the purpose of identifying and quantifying correlates of IVH by constructing an interactive statistical model to predict the occurrence, …

1-Acyldihydropyridones As Synthetic Intermediates, Michael Andrew Foley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The most efficient and stereoselective total synthesis of (+/-)- lausbine II to date has been achieved. The key steps in this are the copper-mediated conjugate addition reaction of the Grignard reagent of 1-bromo-4-chlorobutane to a dihydropyridone and a stereoselective reduction of a quinolizidinone.

Methodology has been developed for the convenient synthesis of 1-acyl-2-substituted-1,2,5,6-tetrahydropyridines. This was accomplished by adding novel alkylzinc iodides to the 1-acyliminium ion derived from N-phenoxycarbonyl-4-methoxy-1,2,3,4-tetrahydropyridine.

Petrology Of Passive Margin-Epeiric Sea Sediments: The Garden City Formation, North-Central Utah, Susan K. Morgan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Lower Ordovician Garden City Formation is part of the thick sequence of Lower Paleozoic limestones, dolostones, and minor siliciclastic sedimentary rocks of the western United States. The carbonate rocks were formed predominantly by shallow water deposition in tropical, passive-margin epeiric seas.

The Garden City Formation is composed of nine lithotypes which represent the various environments. The formation is a storm-influenced transgressive sequence which may be divided into innershelf shallow subtidal and outer-shelf deep subtidal environments separated by a skeletal accumulation. The skeletal accumulation, formed by storm initiation, was a submerged topographic high, below normal wave base. The inner shelf …

Shadow Pattern Simulator, Roberto A. Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper describes an interactive computer program that can be used as a design tool in assessing the shading effects of trees in relation to buildings. The program determines the area and position of the shadow cast by a tree or group of trees on a surface of a building which can have any orientation. The program outputs numerical and graphical hourly results at any time of the day, for any day of the year, at any location on the earth, for any relative positioning between the tree and building, and estimates percent irradiation reductions on building surfaces resulting from …

Insulation Of Small Open Economies In The Presence Of External Disturbances Under Alternative Exchange Rate Systems, Hamid Reza Azad

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study analyzes the determination of the exchange rate system in a small economy when external real and monetary disturbances occur. Choice of exchange rate policy is investigated using a model assuming rational expectations and a loss function expressing the squared deviations of the small country output from desired output. The distinguishing feature of the analysis is the emphasis on real as well as monetary disturbances which originate abroad but are a source of domestic output variation. the link between foreign monetary and real disturbances and variance in output is traced using the thoretical model and the loss function assumed. …

Structure-Activity Relationships Of Retinoids In Developmental Toxicology, W. Brian Howard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The teratogenic potency of retinoid analogs was determined in Syrian hamsters and compared to the teratogenic potency of all-trans-retinoic acid (all-trans-RA, ED₅₀ = 10.5 mg/kg). A total of 15 analogs having variations in the cyclohexene ring were evaluated following various amounts of single oral doses on day 8 of gestation. Retinoids containing a five- or six-membered ring were as teratogenic as all-trans-RA, provided they had sufficient lipophilic substituents on the ring. The same pattern emerged for retinoids that had six-membered aromatic ring substitution for the natural cyclohexene ring of vitamin A. Incorporation of a supplementary …

Interactions Of Vanadium Compounds With Reducing Equivalents: Evidence Of Free Radical Involvement And Possible Mechanisms Of Toxicity, Randal J. Keller

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Vanadium compounds have been reported to cause numerous toxicological effects including NAD(P)H oxidation and lipid peroxidation. The purpose of this thesis is to determine the active form of vanadium in causing these effects, and to determine any possible free radical involvement in these processes. Vanadium-stimulated oxidation of NADH was studied spectrophotometrically and by electron spin resonance spectroscopy. In 25 mM sodium phosphate buffer at pH 7. 4, vanadyl, (V(IV)), is slightly more effective in stimulating NADH oxidation than was vanadate (V(V)). Addition of a superoxide generating system, xanthine/xanthine oxidase, results in a marked increase in NADH oxidation by vanadyl, and …