Digital Commons Network^™

Growth Implant Timing And Effectiveness In Beef Cattle, Herschel Brad Jones

Theses and Dissertations

One hundred crossbred beef steers were used in two experiments to evaluate effects of growth implants on performance. Steers were implanted either at 3.5 months and weaning (CALF); at weaning (WEAN); or not implanted (NONE). In Experiment 1 implanted steers weighed more at weaning (P = 0.01), and had a higher ADG for the entire trial compared to non-implanted steers (P = 0.03). In Experiment 2, at 80 d post wean, implanted steers outweighed NONE (P = 0.09). Overall ADG (P = 0.01) was greater for cattle that were implanted. In the feedlot the CALF group had the lowest ADG …

Habitat Use Of Shovelnose Sturgeon Scaphirhynchus Platorynchus In The Lower Mississippi River, Patrick Thomas Kroboth

Theses and Dissertations

The habitat requirements of shovelnose sturgeon populations are unknown for the lower Mississippi River. Active acoustic telemetry was used to measure temporal variation in habitat use of shovelnose sturgeon and preference for depth, surface current velocity, and riverbed rugosity and slope by the population and within sandbar microhabitats. Shovelnose sturgeon occupied habitats differently throughout the year; and, within habitats, areas of moderate depth and surface current velocity and smooth riverbed were preferred. Within sandbars, environmental conditions did not differ from the surrounding environment, yet frequent aggregations of individuals in the lower portion of sandbars often in close proximity suggest habitat …

Evaluation Of Herbicide Formulation And Spray Nozzle Selection On Physical Spray Drift, Jasper Lewis Cobb

Theses and Dissertations

New transgenic crops are currently being developed which will be tolerant to dicamba and 2,4-D herbicides. This technology could greatly benefit producers who are impacted by weed species that have developed resistance to other herbicides, like glyphosate-resistant Palmer Amaranth. Adoption of this new technology is likely to be rapid and widespread which will lead to an increase in the amount of dicamba and 2,4-D applied each season. It is well-documented that these herbicides are very injurious to soybeans, cotton, tomatoes, and most other broadleaf crops, and their increased use brings along increased chances of physical spray drift onto susceptible crops. …

Examining Hepatic Steroid Inactivation And Luteal Function Throughout Bovine Pregnancy, Caitlin G. Hart

Theses and Dissertations

The objective of this study was to examine hepatic steroid inactivation and luteal function throughout bovine gestation. In pregnant beef cows, cytochrome P450 3A activity decreased from mid- to late-gestation, while progesterone concentrations tended to increase from mid- to late-gestation. Uridine diphosphate-glucuronosyltransferase activity per kg of body weight was increased in pregnant vs non-pregnant dairy cows. Total corpus luteum (CL) blood perfusion tended to be increased in pregnant vs non-pregnant dairy cows. Hepatic portal blood flow per kg of body weight was increased in pregnant vs non-pregnant dairy cows. Hepatic steroid inactivating enzyme activity, CL blood perfusion, and portal blood …

Identification Of The Infection Route Of A Fusarium Seed Pathogen Into Non-Dormant Bromus Tectorum Seeds, Janalynn Franke

Theses and Dissertations

The genus Fusarium has a wide host range and causes many different forms of plant disease. These include seed rot and seedling blight diseases of cultivated plants. The Fusarium-caused diseases of wild plants are less well-known. In this study we examined Fusarium sp. n-caused disease development on non-dormant seeds of the important rangeland weed Bromus tectorum as part of broader studies of the phenomenon of stand failure or ‘die-off’ in this annual grass. We previously isolated an undescribed species in the Fusarium tricinctum species complex from die-off soils and showed that it is pathogenic on seeds. It can cause high …

The Role Of Ceramides In Mediating Endotoxin-Induced Mitochondrial Disruption, Melissa Ellen Hansen

Theses and Dissertations

Ceramides are sphingolipids that serve as important second messengers in an increasing number of stress-induced pathways. Ceramide has long been known to affect the mitochondria, altering both morphology and physiology. Lipopolysaccharide (LPS) is a prevalent circulating inflammatory agent in obesity, potentially mediating some of the pathologies associated with weight gain. Given previous findings of TLR4-mediated ceramide accrual and ceramide-mediated mitochondrial disruption, we questioned whether ceramide is necessary for LPS-induced mitochondrial disruption. We found that LPS treatment increased gene transcript levels of ceramide synthesis enzymes and mitochondrial fission proteins and increased ceramide content in cultured myotubes and in mouse tissue. Mitochondrial …

Replication And Knowledge Production In Empirical Software Engineering Research, Jonathan L. Krein

Theses and Dissertations

Although replication is considered an indispensable part of the scientific method in software engineering, few replication studies are published each year. The rate of replication, however, is not surprising given that replication theory in software engineering is immature. Not only are replication taxonomies varied and difficult to reconcile, but opinions on the role of replication contradict. In general, we have no clear sense of how to build knowledge via replication, particularly given the practical realities of our research field. Consequently, most replications in software engineering yield little useful information. In particular, the vast majority of external replications (i.e., replications performed …

Microchip Thermal Gradient Gas Chromatography, Anzi Wang

Theses and Dissertations

Although the airbath oven is a reliable heating method for gas chromatography (GC), resistive heating is needed for higher analytical throughput and on-site chemical analysis because of size, heating rate and power requirements. In the last thirty years, a variety of resistive heating methods were developed and implemented for both benchtop and portable GC systems. Although fast heating rates and low power consumption have been achieved, losses in column efficiency and resolution, complex construction processes and difficulties experienced in recovering damaged columns have also become problematic for routine use of resistively heated columns. To solve these problems, a new resistively …

Cheatgrass Die-Off Phenomena: What Are The Short And Long Term Recovery Factors Of Bromus Tectorum Stand Failure?, Joshua Alan Nicholson

Theses and Dissertations

Observations of Bromus tectorum L. (cheatgrass or downy brome) monocultures have shown that populations are susceptible to stand die-off or replacement failures. Die-offs, where the seed bank from the previous year fails to emerge, occurs in cheatgrass stands and it is unclear the trigger or cause. The fungus Fusarium has been identified in plant and seed samples from die-offs and may drive die-off activity through pathogenicity. Die-off recovery may take several years but cheatgrass populations eventually reestablish. The purpose of our study was to determine whether Fusarium is a potential player in a die-off, and understand how die-offs recover after …

Framework To Implement Authentication, Authorization And Secure Communications In A Multiuser Collaborative Cax Environment, Francis Mensah

Theses and Dissertations

Computer Aided Design (CAD) applications have historically been based on a single user per application architecture. Although this architecture is still popular to date, it does have several drawbacks. First of all the single user CAD architecture inhibits a concurrent engineering design process where several designers can work on the same model simultaneously. This limitation introduces time inefficiency especially when a project involves geographically dispersed designers. A solution to these drawbacks could be a transition from the traditional single user CAD architecture to a multiuser collaborative architecture. Advances in computer networking technologies, especially relating to the Internet, have provided the …

Fuel Response To Mechanical Mastication Of Pinyon-Juniper Woodlands In Utah, Alan Wyatt Shakespear

Theses and Dissertations

Pinyon-juniper woodland encroachment threatens ecosystem function and diversity on sagebrush steppe. Decreased fire frequency likely favors proliferation of pinyon-juniper woodlands and subsequent decline in desirable understory species. Increased tree cover produces hazardous canopy fuel loads that contribute to severe crown fires and threaten life and property at the wildland-urban-interface. Mechanical mastication converts large canopy fuels into small woody debris, altering wildfire dynamics from a potential crown fire to a more controllable surface fire. We measured fuel loading and cover on untreated, masticated, and masticated + burned treatments on 30-m transects within 30 X 33-m subplots, representing 45 different sites throughout …

Fire And Ungulate Herbivory Differentially Affect The Sexual Reproduction Of Generalist And Specialist Pollinated Plants, Andrew Hollis Lybbert

Theses and Dissertations

Currently the size and frequency of wildfires are increasing at a global scale, including arid ecosystems that exhibit great sensitivity to disturbance. Fire effects on plant pollination and reproductive success in deserts are largely unknown. Plant dependence on animal pollinators for reproduction can increase the risk of reproductive failure if pollination services are hindered or lost. Species that depend on few taxonomically related pollinator species are expected to be most negatively affected by disturbances that disrupt pollination interactions. To assess fire and isolation effects on reproductive success in desert plant communities, and how wildfire influences the pollination success of generalist …

The Bioluminescence Heterozygous Genome Assembler, Jared Calvin Price

Theses and Dissertations

High-throughput DNA sequencing technologies are currently revolutionizing the fields of biology and medicine by elucidating the structure and function of the components of life. Modern DNA sequencing machines typically produce relatively short reads of DNA which are then assembled by software in an attempt to produce a representation of the entire genome. Due to the complex structure of all but the smallest genomes, especially the abundant presence of exact or almost exact repeats, all genome assemblers introduce errors into the final sequence and output a relatively large set of contigs instead of full-length chromosomes (a contig is a DNA sequence …

A Desk Study Of The Education Policy Implications Of Using Data From Multiple Sources: Example Of Primary School Teacher Supply And Demand In Malawi, Moses Khombe

Theses and Dissertations

Malawi, as a country with very limited resources, needs to have educational policies in place to maximize effectiveness of the public education system. Policymakers depend on accurate data, but variations in data between sources leaves policymakers uncertain as they attempt to craft policies to address the growing educational crisis in Malawi. A desk study was performed to evaluate the policy implications of employing data from multiple sources using primary school teacher supply and demand in Malawi as an illustration. This study examined one national organization, Malawi's Ministry of Education, Science, and Technology (MoEST); three international aid and assistance organizations (IAAOs), …

Orientalism And "Authentic Homosexual": How "The Closet" Reinforces Hegemonic Knowledge And Binary Logic, Contributing To The Invisibility Of Non-Conforming Gender And Sexual Identities, Michelle Bonapace-Potvin

Theses and Dissertations

The critique of Orientalism's binary logic finds a complementary analysis in the questioning of static sexual and gender categories. There is already significant research that points to these intersectional critiques—for instance, Joseph Massad's Desiring Arabs and Jasbir K. Puar’s Terrorist Assemblages: Homonationalism in Queer Times. In this paper, I will use analyses of Orientalism to review the ways in which hegemonic knowledge and binary logic contribute to the invisibility of non- conforming gender and sexual identities. In other words, I will use the language and lens of critiques of Orientalism to observe, analyze, and comment on the current politics of …

Psychometrics And Test-Enhanced Learning In A Patient-Centered Learning Curriculum, Syed Haris Ali

Theses and Dissertations

Validity and reliability of scores obtained on Multiple-choice questions (MCQs), as well as the benefits of test-enhanced learning, have been of interest to medical educator scholars. Presented in this dissertation are four composite studies on these themes. The following hypotheses were tested:

1. Increased MCQ distractor functioning increases the validity and reliability of obtained scores.

2. Correction of item writing flaws (along with enhancement of tested cognitive level) and replacement or removal of non-functioning distractors equally improves psychometric characteristics of MCQs.

3. Repeated testing via free-response items enhances the retention of knowledge of human anatomy, compared with repeated or once-testing …

Synthesis And Characterization Of Complex Molecular Assemblies On Surfaces, Nitesh Madaan

Theses and Dissertations

The research presented in this dissertation is focused on the construction of complex molecular structures on planar gold and silicon dioxide surfaces using a variety of surface modification techniques, along with thorough surface characterization at each modification step. The dissertation is structured into six separate chapters. In Chapter 1, an introduction to the importance and implications of molecular level surface modification, commonly employed surface modification methods, and available surface characterization techniques is presented. Chapter 2 shows applications of novel methodologies for the functionalization of gold surfaces using alkane dithiol self-assembled monolayers and thiol-ene click chemistry. The resulting functionalized gold substrates …

Chaperone-Mediated Folding And Assembly Of Β-Propeller Proteins Into Cellular Signaling Complexes, Rebecca L. Plimpton

Theses and Dissertations

G protein signaling depends on the ability of the individual subunits of the G protein heterotrimer to assemble into a functional complex. Formation of the G protein βγ (Gβγ) dimer is particularly challenging because it is an obligate dimer in which the individual subunits are unstable on their own. Recent studies have revealed an intricate chaperone system that brings the Gβ and Gγ subunits together. This system includes the cytosolic chaperonin containing TCP-1 (CCT) and a co-chaperone phosducin-like protein 1 (PhLP1). Two key intermediates in the Gβγ assembly process, the Gβ-CCT and the PhLP1-Gβ-CCT complexes, were isolated and their structures …

A Study Of The American Black Bear (Ursus Americanus) In Utah: An Analysis Of The Post-Denning Activities And Bear-Human Conflict, Julie Ann Miller

Theses and Dissertations

This study examined two different aspects of black bear (Ursus americanus) ecology in Utah. First, we determined the post-denning behaviors of female black bears in order to help management agencies protect bears from human disturbances as well as set spring hunts that minimize the taking of females with dependent young. We looked at the timing of den emergence (X = 25 March), the number of days at the den site post emergence (X = 11 days), and departure (X = 8 April) for female black bears in Utah from 2011—2013. We also analyzed the effects of cohort (lone …

Generality Of The Terminal Investment Hypothesis: Effects Of Extrinsic Mortality And Resource Availability On Age-Related Reproductive Investment, Allystair Jones

Theses and Dissertations

A central question in life history theory is, what combination of traits and behaviors will lead to the highest reproductive success throughout a lifetime. The trade-off between current and future reproduction is central to the lifetime reproductive success of an organism. If there is a cost to reproduction, then allocation of energy to current reproduction will come at a cost to future reproduction. We expect young individuals to favor future reproduction over current reproduction and that balance shifts to current reproduction as they age (i.e. terminal investment hypothesis). However, how this transition from an emphasis on future reproduction to emphasis …

Understanding The Diversification Of Central American Freshwater Fishes Using Comparative Phylogeography And Species Delimitation, Justin C. Bagley

Theses and Dissertations

Phylogeography and molecular phylogenetics have proven remarkably useful for understanding the patterns and processes influencing historical diversification of biotic lineages at and below the species level, as well as delimiting morphologically cryptic species. In this dissertation, I used an integrative approach coupling comparative phylogeography and coalescent-based species delimitation to improve our understanding of the biogeography and species limits of Central American freshwater fishes. In Chapter 1, I conducted a literature review of the contributions of phylogeography to understanding the origins and maintenance of lower Central American biodiversity, in light of the geological and ecological setting. I highlighted emerging phylogeographic patterns, …

The Word Problem Factor: Assessing The Ability Of Utah High School Career And Technical Education Students To Do The Math Involved In Formulating And Calculating Energy Cost Factors, Kristen Bentley

Theses and Dissertations

Much research has been done showing the difficulty people have with word problems. This has been shown to be true for many types of word problems and for different demographics. Questions have remained unanswered regarding the reasons for this difficulty. It has been unclear if the word problems were hard because the people had forgotten or had not yet learned how to do the math calculations involved or for some other reason. This study deals with high school students who are currently in a high school level math class. They were given an assessment involving word problems and number-only problems. …

Spatial Heterogeneity Of Ecosystem Metabolism In A Shallow Wetland, Daniel Riley Rackliffe

Theses and Dissertations

Spatial heterogeneity in ecosystem metabolism may play a critical role in determining ecosystem functions. Variation in ecosystem metabolism between macrophyte patches in shallow wetlands at the extremes of freshwater habitats has not been investigated. We estimated ecosystem metabolism in mesocosms containing different macrophytes using 24-hour oxygen curves to test our hypotheses: (1) net aquatic production (NAP) during spring and summer would be similar among algal patches (metaphyton and Chara), (2) NAP in algal patches would be greater than patches dominated by the vascular plant Potamogeton foliosus, (3) heterotrophy and anaerobiosis would be greatest in patches dominated by Lemna, and (4) …

A Molecular Phylogeny Of Lampyridae With Insight Into Visual And Bioluminescent Evolution, Gavin Jon Martin

Theses and Dissertations

Fireflies are some of the most captivating organisms on the planet. Because of this, they have a rich history of study, especially concerning their bioluminescent and visual behavior. Among insects, opsin copy number variation has been shown to be quite diverse. However, within the beetles, very little work on opsins has been conducted. Here we look at the visual system of fireflies (Coleoptera: Lampyridae), which offer an elegant system in which to study visual evolution as it relates to their behavior and broader ecology. They are the best-known case of a terrestrial organism that communicates through the use bioluminescence. The …

The Effects Of Nebulized Saline Treatments On Diphthongal Vowel Production On Female Subjects With Sjögren's Syndrome, Keri Lynn Perry

Theses and Dissertations

The purpose of this study was to analyze and quantify the effects of a nebulized saline treatment on speech production in eight females with Primary Sjögren's Syndrome (SS). The duration, formant frequency onset and offset, and slope were measured to determine the quality of participants' production of diphthongal American English vowels. Acoustic data were examined before treatment began, immediately following treatment, and during a one-week follow-up to determine the effects of a laryngeal hydration program that used nebulized saline to increase hydration of structures in the vocal tract. The vowels produced during the initial baseline condition were acoustically relatively similar …

Microvascular Function In Metabolically Healthy Groups Differing In Bmi And Waist Circumference, Nathan R. Earl

Theses and Dissertations

BACKGROUND: Microvascular dysfunction (MD: impaired performance of blood flow, tissue perfusion, blood pressure, etc.) is one of the earliest stages in the progression of various chronic diseases. OBJECTIVE: The aim of this study was to determine if a difference in microvascular function existed between two metabolically healthy groups that differed in BMI and waist circumference. DESIGN: This study employed a causal comparative design, with two groups: I) normal weight (n =14, BMI 28 kg/m2). METHODS: Microvascular function was assessed by measuring skin blood flow (SkBF) using laser Doppler flowmetry during postocclusive reactive hyperemia (PORH). The area under the SkBF time …

Studies Of Phou In Escherichia Coli: Metal Binding, Dimerization,Protein/Protein Interactions, And A Signaling Complex Model, Stewart G. Gardner

Theses and Dissertations

Phosphate is an essential nutrient for all forms of life. Escherichia coli has a PhoR/PhoB two component regulatory system that controls the expression of various genes whose products allow the cell to thrive in low phosphate environments. The signaling mechanism of the PhoR/PhoB system has been studied and the phosphorylation cascade that controls gene expression is well understood. What is still unknown is how PhoR senses the phosphate level of the environment. The PstS, PstC, PstA, PstB, and PhoU proteins play a role in this signal sensing. This work confirms the hypothesis that the PstSCAB complex senses the environmental phosphate …

Variation In Resource Utilization And Cost Of Reproduction For Two Burying Beetle Species, Peter J. Meyers

Theses and Dissertations

The cost of reproduction hypothesis suggests that allocation into current reproduction constrains future reproduction. How organisms accrue reproductive costs may differ between species and with varying levels of resource quality. Burying beetles are model organisms for testing for the cost of reproduction because of their unique natural history; beetles utilize small vertebrate carcasses for reproduction and they and their offspring feed exclusively on these discrete resources. Burying beetles also can utilize a large range of carcass sizes for reproduction. We tested for the cost of reproduction in two species of burying beetles, Nicrophorus marginatus and Nicrophorus guttula found in Central …

Alcohol Modulation Of Dopamine Release, Nathan Dan Schilaty

Theses and Dissertations

The mesolimbic dopamine (DA) system projects from the ventral tegmental area (VTA) to structures associated with the limbic system, primarily the nucleus accumbens (NAc). This system has been implicated in the rewarding effects of drugs of abuse. Many drugs of abuse act in the VTA, the NAc, or both. Dopamine neurons in the VTA that project to the NAc, and the GABA neurons that inhibit DA neurons locally in the VTA or project to the NAc, play an important role in mediating addiction to various drugs of abuse, in particular alcohol. There is a growing body of evidence of co-dependence …

The Impacts Of Feral Horses On The Use Of Water By Pronghorn On The Sheldon National Wildlife Refuge, Nevada, Amy Marie Gooch

Theses and Dissertations

Feral horses occupy 31.6 million acres throughout western North America. Feral horses share similar habitats with a wide range of animal species, including pronghorn. Since horses are larger and often more aggressive than other animals of this region, they are generally socially dominant over all other native ungulate species. Pronghorn share water sources with horses in areas where both occur. In situations where horses exclude pronghorn from water, pronghorn fitness may be impaired, especially during the hottest months of the year when water is limited. The purpose of this study was to investigate interference competition between pronghorn and feral horses …