Digital Commons Network^™

Patterns Of Threatened Vertebrates Based On Trophic Level, Diet, And Biogeography, Shaley A. Valentine

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Humans have indirectly and directly contributed to the extinction of over 500 species within the past 500 years, a rate far higher than we have seen in the past. The high extinction rate and the fact that 18% of vertebrates may become extinct within the next century have pushed Earth into a biodiversity crisis. Understanding what makes species more at risk of extinction is needed to protect Earth’s biodiversity.

Generally, it is expected that predators have greater extinction risk than omnivores and herbivores because predators are larger in body size, depend on other animal species for food, need large home …

Pharmacologically Induced Meiosis Apomeiosis Interconversions In Boechera, Arabidopsis And Vigna, Lei Gao

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Apomixis is a clonal propagation method that produces offspring identical to the mother plant. With this feature, superior traits could be maintained over generations. However, our knowledge about apomixis is limited. In this study, we analyzed several apomictic Boechera embryologically to learn the details of apomixis. Meanwhile, we designed chemical treatments to successfully induce sex in apomictic plants and apomixis in sexual plants. Our experiments suggest that sex and apomixis coexist in plants and that sexual and apomictic reproduction are switchable by treating with specific chemicals.

Invasive Phragmites Australis Management In Great Salt Lake Wetlands: Context Dependency And Scale Effects On Vegetation And Seed Banks, Christine B. Rohal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Invasive plants can outcompete native plants, replacing diverse plant communities with monocultures, which can negatively impact the whole ecosystem. One invasive plant, Phragmites australis, has invaded wetlands across North America. In Utah’s Great Salt Lake, it has greatly reduced the area of native plants that are important habitat for migratory birds. Here we describe experiments that assess multiple treatments for Phragmites removal and evaluate the return of native plants after Phragmites management. The treatments were applied to Phragmites patches at two scales (small 1/4-acre plots and large 3-acre plots) and across multiple sites to evaluate how patch size and …

Relationships Among Invasive Coqui Frogs, The Small Indian Mongoose And Rat Species In Hawaii, Shane A. Hill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-native species are increasing globally, and with this increase, it is likely that there will be new, unique relationships found among non-natives as well as additional impacts on native species. Rats and mongooses have been introduced to islands throughout the world where they impact native species, including birds, reptiles, and amphibians. The coqui frog was introduced to Hawaii in the 1980’s, where there were already abundant rat and mongoose populations. Previous research suggests that the high densities of coqui frogs may provide enough of a new food source for mongooses and rats that their populations would grow larger than they …

Integrated Management Of Billbugs (Coleoptera: Dryophthoridae) In Intermountain West Turfgrass, Madeleine M. Dupuy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Billbugs are a serious pest of turfgrass in the Intermountain West. Billbug larvae severely discolor and eventually kill turfgrass by feeding in stems, on roots, and on crowns of the plant. Billbugs are typically managed with preventive, calendar-based applications of insecticides. Most of our knowledge on the biology and management of billbugs comes from research in the eastern U.S, and little is known about billbug biology and best management practices in the Intermountain West. First, I examined the seasonal activity of billbug life stages in Intermountain West turfgrass and developed a predictive degree-day model to better time management strategies against …

Effect Of Tannin-Containing Legume Hays On Enteric Methane Emissions And Nitrogen Partitioning In Beef Cattle, Elizabeth K. Stewart

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cattle are responsible for greenhouse gas emissions such as carbon dioxide, methane and nitrous oxide. In particular, the cow-calf phase of production accounts for approximately 80 percent of the total beef production system greenhouse gas emissions. Tannins are chemical compounds found in certain forages and they have the potential to help reduce these negative environmental impacts. Thus, given that the cow-calf phase often relies on feeding hay, feeding tannin-containing hays may represent a significant mitigation practice.

With my MS program, I sought to explore whether tannin-containing hays fed to mother cows and heifers influence methane and nitrogen emissions relative to …

An Experimental Comparison Of Student Motivation Between Two Computational Thinking-Based Stem Activities: Vex-Based Automation And Robotics And A Quadcopter Activity, Cory J. Ortiz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to compare student motivation between two junior high level computational thinking based STEM curricular activities. These two activities were a newly developed quadcopter based curriculum and a VEX based curricular activity developed for Project Lead the Way’s Gateway to Technology – Automation and Robotics course. Student motivation was assessed using an assessment called My Class Activities which broke motivation into four constructs: interest, challenge, choice, and enjoyment.

This study assessed students in three schools in a northern Utah school district. Students were assessed after receiving each curriculum. Assessment responses were then coded and analyzed. …

Planning For Active Transportation In The Western United States: An Alternative Future For Cache Valley, Utah, Stephanie A. Tomlin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mobility in the western U.S. is defined primarily by the private automobile. Since the conclusion of WWII, the private automobile has become readily available to the public, and as a result, has heavily influenced the design of our modern cities in the west. In recent years the connections between high motor vehicle use and rising obesity rates, crumbling road infrastructure, and deteriorating air quality have caused city officials to reexamine the transportation systems of the west. One solution advocates, city officials, and planning professionals have begun examining is active transportation (walking, cycling, and public transit). Research suggests that a robust …

Engelmann Spruce Survival And Regeneration After An Epidemic Spruce Beetle Outbreak On The Markagunt Plateau In Southern Utah, Jessika M. Pettit

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bark beetle outbreaks are becoming more intense and severe when coupled with the effects of climate change. Engelmann spruce (Picea engelmannii) is one such species facing large-scale, epidemic spruce beetle outbreaks. Large-scale disturbances, such as beetle outbreaks, have major consequences for the future success of the ecosystem, thus highlighting the importance of understanding what promotes amplified outbreaks as well as their effects on future seedling establishment. Our research focused on two parts of a large-scale beetle outbreak: the mortality of spruce trees and the subsequent regeneration of seedlings. Our first study examined the timing of spruce mortality during …

Electron Flow And Management In Living Systems: Advancing Understanding Of Electron Transfer To Nitrogenase, Rhesa N. Ledbetter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen is a critical nutrient for growth and reproduction in living organisms. Although the Earth's atmosphere is composed of ~80% nitrogen gas (N₂), it is inaccessible to most living organisms in that form. Biological nitrogen fixation, however, can be performed by microbes that harbor the enzyme nitrogenase. This enzyme converts N₂ into bioavailable ammonia (NH₃) and accounts for at least half of the "fixed" nitrogen on the planet. The other major contributor to ammonia production is the industrial Haber-Bosch process. While the Haber-Bosch process has made significant advances in sustaining the global food supply through …

Biological Condition And Stressors Of Blm Wadeable Streams In Northeastern California And Northwestern Nevada, Nicole Cappuccio

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Taxpayer dollars can be used more efficiently by land management agencies to monitor streams if agency-wide monitoring protocols are adopted. To address this issue, the Bureau of Land Management (BLM) developed the National Aquatic Monitoring Framework (NAMF) to implement standardized assessments of stream condition and trend in the Western United States. As one of the first applications of the NAMF I sought to develop and apply an analytical framework to determine the biological condition of streams, extent of instream stressors and their impact on biological condition, and anthropogenic sources of stressors in Northeast California and Northwest Nevada over three years …

Quantifying Dominant Heat Fluxes In An Arctic Alaskan River With Mechanistic River Temperature Modeling, Tyler V. King

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Temperatures strongly affect physical, chemical, and biological processes in rivers and streams. The processes that influence river temperatures are known across most geographic regions, but the relative importance varies significantly. Little is known about what controls water temperature Arctic rivers, limiting our ability to understand the impacts of climate change. This dissertation addresses this knowledge gap by incorporating field measurements with river temperature modeling to estimate the relative importance of key factors that affect Arctic river temperatures. Results indicate that shortwave radiation (e.g., sunlight) and net longwave radiation are significant throughout an Arctic watershed in all flow conditions. In areas …

Investigations Into Factors Affecting The Wpd-Loop In The Protein Tyrosine Phosphatases Yoph And Ptp1b, Gwendolyn Moise

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The research in this dissertation documents connections between the primary amino acid sequence of proteins, the dynamics of proteins, and their catalytic function. This research project studied two proteins called protein-tyrosine phosphatases (PTPs): the human enzyme PTP1B, and the bacterial enzyme YopH. PTP1B is a human enzyme that down regulates the insulin receptor on the outer cellular membrane, and causes the insulin receptor to be less responsive to insulin. A deeper knowledge of how PTP1B is different from other human PTPs might be useful in designing drugs to increase insulin sensitivity in diabetics. Yersinia Pestis is the bacteria that caused …

Development And Optimization Of A Produced Water, Biofilm Based Microalgae Cultivation System For Biocrude Conversion With Hydrothermal Liquefaction, Benjamin L. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extraction of oil and gas in Utah’s Uintah Basin results in large quantities of wastewater, or produced water, with nutrients and residual organic chemical that represent a significant resource for producing energy-related and value-added products. Produced water was obtained as a biomass producing nutrient source from industries operating in Utah’s Uintah Basin. Within the Uintah Basin (defined as Uintah and Duchesne Counties within Utah) approximately 93 million barrels of water were produced in 2013 while only 11% of the water was disposed of through evaporation, with the national average at 2%. The rest is reinjected into the subsurface.

The goal …

The Culture Of Sexuality: Identification, Conceptualization, And Acculturation Processes Within Sexual Minority And Heterosexual Cultures, Joshua Glenn Parmenter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study aimed to provide insights into the experiences of lesbian, gay, bisexual, transgender, or queer/questioning (LGBTQ+) people within LGBTQ+ culture, and to explore how they disclose or conceal their sexual identities within different social environments. A qualitative study enabled me to become immersed within the stories of LGBTQ+ people, in order to better understand the construct and importance of LGBTQ+ culture. Through in-depth interviews and focus groups, 14 members of the LGBTQ+ community from around the nation volunteered to share their experiences with LGBTQ+ culture and their negotiation of identity within heterosexual culture.

From participants’ stories, key themes were …

Novel Methods To Produce Large Recombinant Spider Silk Proteins Via Polymerization, Nathan L. Hebert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spider silk has long been a subject of scientific research due to its remarkable mechanical properties. Until recently, there has been no way to effectively obtain spider silk except by harvesting it from individual spiders. With advances in technology, the genes that code for the individual spider silk proteins have been isolated and genetically engineered into other hosts to produce recombinant spider silk proteins (rSSp) of varying sizes, Larger rSSp have correspondingly greater mechanical properties in any resulting materials. Using current production methods, larger rSSp cannot be produced in commercially viable quantities while simultaneously being economically viable. The current production …

Effects Of Livestock Grazing Management Practices On Greater Sage-Grouse Nest And Female Survival, Seth J. Dettenmaier

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The decline in greater sage-grouse (Centrocercus urophasianus; sage-grouse) populations across western North America has been primarily attributed to loss and fragmentation of their sagebrush (Artemisia spp.) habitats. This habitat loss is largely the result of increased human activities, with grazing by domestic livestock as the most predominant land use across the sagebrush ecosystem in North America. The goal of my research was to increase our understanding of the effects of livestock on sage-grouse populations. I reviewed the peer-reviewed literature for all published studies that reported potential effects of grazing on grouse species worldwide. I found that there …

Development And Fitness Consequences Of Onshore Behavior Among Polar Bears In The Southern Beaufort Sea Subpopulation, Kate M. Lillie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Polar bears (Ursus maritimus) are experiencing rapid and substantial changes to their environment due to global climate change. Polar bears of the southern Beaufort Sea (SB) have historically spent most of the year on the sea ice. However, recent reports from Alaska indicate that the proportion of the SB subpopulation observed onshore during late summer and early fall has increased considerably. Previous research suggests that the number of polar bears onshore is linked to sea ice conditions and the availability of subsistence-harvested whale carcasses, which are referred to as bone piles. My objectives were to determine the development …

Development And Characterization Of Aqueous-Based Recombinant Spider Silk Protein Biomaterials With Investigations Into Potential Applications, Thomas I. Harris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spider silks are incredible natural materials that possess desirable combinations of strength, elasticity, weight, and robustness. Other properties such as biocompatibility and biodegradability further increase the worth of these materials. The possibility of farming spiders is impractical due to spiders’ natural behaviors. Modern biotechnologies have allowed for recombinant spider silk proteins (rSSps) to be produced without the use of spiders. However, the features responsible for spider silks impressive properties can cause difficulties with producing silk materials. A recently developed water-based and biomimetic solvation method has provided a solution to such difficulties and has also led to novel silk biomaterials. Most …

Enhancing Spider-Silk Protein Materials Through Continuous Electrospinning And Photo-Initiated Cross-Linking, Dan Gil

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spider-silk is known as one of the stronger natural materials, unfortunately it is impossible to farm spiders due to their territorial and cannibalistic nature. To address this issue, researchers have studied spider-silk to discover how it is produced in nature. From their results, spider-silk is composed of large sized proteins produced in two different cell types. Using this knowledge, researchers created transgenic organisms capable of producing spider-silk proteins in large quantities. Using these proteins, several groups have created fibers, films, hydrogels, and adhesives with robust and versatile properties.

Wet-spinning is a technique commonly used to create fibers from spider-silk proteins. …

Contextual Factors In The Identity Development Of Native American And Latinx Undergraduates In Stem Fields, Angela Marie Enno

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study includes two papers that aimed to provide insights into the experiences of high-achieving Latinx and Native American college students studying science. We wanted to better understand factors that influence these students’ ability to develop a sense of identity that weaves together their hoped-for careers as scientists as well as their cultural identities. We looked at how they feel about working with mentors in science fields who were like them in a variety of ways. We found that many students (especially those with a stronger sense of cultural identity) valued working with mentors who were similar to them in …

Chronic Migraines And Couples: A Grounded Theory Of Adaptation To Chronic Migraines For Patients And Their Partners, Douglas P. Mcphee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was completed to better understand and treat couples wherein one partner suffers from chronic migraines. I interviewed eight couples about their experiences in dealing with migraines as a patient, as a partner, and together. The interviews were transcribed and analyzed by a team of seven researchers. We developed a theory that can be used to understand how patients and their partners adapt to chronic migraines. The theory was grounded in the experiences of the patients and partners who were interviewed. We found that patients and partners alike dealt with burdens and costs associated with chronic migraines. Coping, healthcare, …

Biomass And Phycocyanin From Oil And Natural Gas Extraction Produced Water Utilizing A Cyanobacteria Dominated Rotating Algal Biofilm Reactor (Rabr), Jonathan L. Wood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The production of cyanobacterial biofilm biomass and phycocyanin from Rotating Algal Biofilm Reactors utilizing undiluted produced water from oil and natural gas extraction as a culture medium was investigated in this study. Produced water is the largest waste stream generated by the oil and natural gas industries and represents a large volume of non-potable water that may be available for algae culture with minimal impact on freshwater resources. Combining the use of produced wastewater as culture medium with the production of high value algal pigments, such as phycocyanin, may increase the economic viability of algae culture and wastewater purification. High …

Socioeconomic Status Influence On Mothers’ Interactions With Infants: Contributions To Early Infant Development, Krista L. Gurko

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Children from different socioeconomic backgrounds often have different long-term outcomes in terms of school, language, and emotional wellbeing. At this time, no reasons for these differences have been agreed upon by experts across disciplines. Parents with different personal characteristics and life situations use different types and amounts of interactions with their infants. The social interactions infants experience during their first year of life provide the start of their developmental path in the areas of language and executive control while also guiding their expectations for interactions with people around them.

This study used previously unpublished data from a sample of 79 …

Changing Delay Discounting: Identification And Evaluation Of Ecologically Valid Methods For Reducing Impulsive Choice, Jillian M. Rung

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Impulsivity takes many forms, one of which is termed impulsive choice. Impulsive choice entails preference for an outcome due to its immediacy relative to more optimal outcomes that take longer to come to fruition. For example, one may wish to have another serving of a decadent dessert after dinner—but doing so may undermine a longer-term goal of improved health and nutrition. If having the extra serving becomes a habit, the consequences of that choice compound and may lead to, for example, obesity. A high degree of impulsive choice such as this is indeed related to issues such as obesity, …

Comparative Pollination Efficacies Of Bees On Raspberry And The Management Of Osmia Lignaria For Late Blooming Crops, Corey J. Andrikopoulos

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Unlike other rosaceous fruit crops such as apple and cherry, commercial raspberry cultivars are largely self-fertile and can set fruit in the absence of pollinators. However, their floral morphology often prevents complete self-pollaintion. Incomplete pollination yields unmarketable small or crumbly fruits. Insect visitation is therefore essential to maximizing raspberry yield. Honey bees are typically used to pollinate commercial raspberry; however, escalating prices for hive rentals coupled with increasing acreage encourage evaluation of other manageable pollinators. Bumble bees (Bombus spp.) and several mason bees (Osmia spp.) are promising raspberry pollinators. Five bee species were evaluated and compared for their …

Using Anthropogenic Risks To Inform Salmonid Conservation At The Landscape Scale, Andrew W. Witt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The expansion and industrialization of humanity has caused many unforeseen consequences to the natural world. Due to the importance of freshwater for people, rivers have been particularly altered to meet human needs, often at the expense of the natural world. Supplying water for farms, industries, and cities has reshaped the natural state of rivers by altering river paths, chemistry, and species compositions. These changes have harmed many species that prospered before widespread human alterations, including the native trout and salmon of western North America. As human populations continue to grow, new threats will surface for rivers, and the trout and …

Understanding Plant Secondary Metabolites; Above And Below Ground, Andrea K. Clemensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plants naturally produce primary and secondary metabolites. Primary metabolites are directly involved with plant growth and metabolic function. Plant secondary metabolites (PSM) were once thought of as metabolic waste products, and more recently viewed as toxins to herbivores. However, ongoing research shows that PSM are beneficial to herbivores at low doses, and PSM aid plants by attracting pollinators, recovering from injury, protecting from ultraviolet radiation, increasing drought tolerance, and aid in defense against pathogens, diseases, and herbivores. Plant secondary metabolites also influence soil nutrient cycling, and can increase the sustainability of agroecosystems. Endophyte-infected tall fescue (Festuca arundinacea Schreb.), which …

Humans As Sensors: The Influence Of Extreme Heat Vulnerability Factors On Risk Perceptions Across The Contiguous United States, Forrest Scott Schoessow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extreme heat events are the deadliest natural hazard in the United States and will continue to get worse in the coming years due to the effects of climate change. As a result, more people will experience deadly heat conditions. This highlights the need for decision-makers to develop better strategies for preventing future losses. How badly individuals are affected by extreme heat depends on many circumstances, such as how high temperatures actually are, weather conditions, and location. For example, a dry 90 °F day in Phoenix is probably more tolerable than a humid 90 °F day in New Orleans for most …

A Deep Learning Approach To Recognizing Bees In Video Analysis Of Bee Traffic, Astha Tiwari

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Colony Collapse Disorder (CCD) has been a major threat to bee colonies around the world which affects vital human food crop pollination. The decline in bee population can have tragic consequences, for humans as well as the bees and the ecosystem. Bee health has been a cause of urgent concern for farmers and scientists around the world for at least a decade but a specific cause for the phenomenon has yet to be conclusively identified.

This work uses Artificial Intelligence and Computer Vision approaches to develop and analyze techniques to help in continuous monitoring of bee traffic which will further …