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Environmental Influences On Tree-Driven Karst Bedrock Physical Weathering, Cole Robert Jimerson

Graduate Theses and Dissertations

The role of tree roots as stressors that contribute to physical weathering processes and thus soil generation remains an open question in critical zone science. While evidence suggests roots may be able to damage rock by accessing pre-existing fractures, where they can expand due to water uptake or generate forces on rock in response to wind gusts, these processes have not been investigated in temperate karst regions until now. I monitored forces at the root-rock interface for an American elm and Hackberry tree between September 2019 and May 2020. I used piezoelectric force sensors to determine if differences in species, …

The Conservation And Population Ecology Of The Imperiled Crawfish Frog (Lithobates Areolatus) In Human-Altered Landscapes, Chelsea Shannon Kross

Graduate Theses and Dissertations

The Crawfish Frog (Lithobates areolatus) is an imperiled amphibian currently experiencing severe declines across its range. As a species with unique habitat requirements that is threatened by habitat loss, understanding their status across the landscape and how they respond to environmental stressors is key to developing effective conservation strategies that maintain and expand viable populations. We used a combination of observational, experimental, and theoretical approaches to understand the status of Crawfish Frog populations in Northwest Arkansas (NWA), their individual and population-level response to human-induced changes in vegetation surrounding breeding wetlands, and the effects of fire management on larval development within …

A Study Of The Thermodynamics Of Small Systems And Phase Transition In Bulk Square Well-Hard Disk Binary Mixture, Gulce Kalyoncu

Graduate Theses and Dissertations

Under the umbrella of statistical mechanics and particle-based simulations, two distinct problems have been discussed in this study. The first part included systems of finite clusters of three and 13 particles, where the particles are interacting via Lennard Jones potential. A machine learning technique, Diffusion Maps (DMap), has been employed to the large datasets of thermodynamically small systems from Monte Carlo simulations in order to identify the structural and energetic changes in these systems. DMap suggests at most three dimensions are required to describe and identify the systems with 9 (N = 3) and 39 (N = 13) dimensions. At …

Drinking To Cope: Effects Of Anxiety On Generation Of Self-Regulation Strategies, Lauren Hurd

Graduate Theses and Dissertations

This study sought to utilize motivational and self-regulatory processes, specifically the principle of emotional transfer (PET), to elucidate mechanisms underlying the transition from casual alcohol use to dependence in young adults with elevated anxiety. Utilizing a script-driven imagery procedure, the proposed study examined the effects of manipulated state anxiety on 1) the amount, content, and commitment to freely generated anxiety reduction strategies, and 2) the level of craving for alcohol. Young adult college students (N = 69; ages 18-24; 76.8% women) were randomly assigned to either the high (n = 35) or low (n = 34) anxiety condition. After script …

Genetics Of Physiological Traits Associated With Drought Tolerance In Soybean (Glycine Max), Sumandeep Kaur Bazzer

Graduate Theses and Dissertations

Soybean (Glycine max L.) is one of the major row crops in the United States, and its production is often limited by drought stress. Physiological traits from exotic germplasm that confer drought tolerance may be useful in improving commercial soybean production. For example, carbon isotope ratio (δ13C) is positively correlated with water use efficiency (WUE), and nitrogen isotope ratio (δ15N) is negatively correlated with N2 fixation; canopy temperature (CT) is an indicator for genetic variation in transpiration and stomatal conductance. Therefore, the objectives of this research were to identify the genomic regions associated with: (1) δ13C and δ15N using a …

A Macroevolutionary View On Extinction In Aves, Chiroptera, And Odonata, Peter Hasik

Graduate Theses and Dissertations

A central goal of conservation biology is to identify and understand the factors that lead to extinction. The Earth is currently undergoing a 6th mass extinction event, in large part because of human activity. In the last century, rates of extinction have increased anywhere from 8-100 times the background rate of 2 extinctions per 10,000 species every 100 years. However, there remains a debate over whether certain species are predisposed to a higher extinction risk. In particular, it is not known if the macroevolutionary history of a lineage is a major contributor to the probability of extinction, nor is it …

Children's Use Of Accent As A Cue For Cooperative Potential, Rachel Stevens

Graduate Theses and Dissertations

In recent years, several studies have shown that 5- and 6-year-old children make social judgments based on accent, consistently displaying a social preference for individuals who speak with a native accent. One theory hypothesizes that this preference to favor individuals who speak like us stems from our evolutionary history, during which accent and other language variations would have been strong, salient cues to group membership, and thus, cues to ones likelihood of cooperative behavior. The current study aimed to test this theory by determining if 5- and 6-year-old children use accent to make judgments about an individual’s cooperative potential. Participants …

Long-Term Impact Of Child-Centered Play Therapy On Academic Achievement: A Longitudinal Examination Of Academic Success In At-Risk Elementary School Students, Brittany D. Massengale

Graduate Theses and Dissertations

This study examined the long-term impact of child-centered play therapy (CCPT) implemented through Primary Project on at-risk second-grade elementary school students. The qualifying group received ten 30-minute play therapy sessions during one academic semester during their second-grade year. In a longitudinal analysis for academic growth, MAP testing was used to determine if there was a long-term impact on both the third grade and fourth-grade years for the original qualifying students. The findings reveal implications for identification of and interventions for at-risk elementary students and CCPT as an intervention for academic achievement; specifically, reading and mathematics scores. Recommendations for future research …

Phenotypic And Genotypic Studies In The Peach [Prunus Persica (L.) Batsch] And Muscadine Grape (Vitis Rotundifolia Michx.), Jennifer Anne Lewter

Graduate Theses and Dissertations

Peach: Peaches [Prunus persica (L.) Batsch] are routinely chilled to increase shelf-life. Exposure to temperatures of 5° C for two weeks can induce chilling injury (CI) symptoms, including flesh mealiness (or wooliness) and a lack of juiciness. Phenotypic data were collected on seven biparental F1 peach populations maintained at the University of Arkansas Fruit Research Station. A genome wide association study (GWAS) was performed using TASSEL 5 which identified four quantitative trait loci (QTLs) associated with expressible juice, four QTLs for mealiness, five QTLs for soluble solids, and three QTLs for fruit weight. Exploiting these genetic markers could help breeders …

Relationship Between University Student Characteristics And Water Conservation Behaviors, Matthew A. Wise

Graduate Theses and Dissertations

Water over-consumption is a critical issue due to it being a mismanaged, and virtually finite, natural resource. In order to convey this information to the public and promote change, it is important to understand the public’s current attitude towards the topic in order to develop more targeted teaching approaches. The purpose of this study was to determine college-age students’ perceptions about water resource usage, their personal levels of active engagement in water conservation, and if any differences existed between agriculture students and non-agriculture students. This study utilized an online quantitative survey, guided by the Theory of Planned Behavior, which was …

Ensemble And Single Particle Studies Of Cation Exchange In Cuins2/Zns Qds And Their Application In Super-Resolution Imaging, Anh Tue Nguyen

Graduate Theses and Dissertations

Colloidal quantum dots (QDs) have great potential in many applications such as bioimaging, light emitting diodes, solar cells and lasers. However, a great number of studies have been focused on Cd based (II-VI) and Pb (IV-VI) based materials which are not suitable for mass production. Therefore, alternative types of QD containing less toxic materials have been introduced, including CuInS2 QDs. This I-III-VI semiconductor nanocrystals also attract lots of attention due to their large Stock shift, long fluorescence lifetime and high defect tolerance, making them attractive emitters for applications in bioimaging, photovoltaics and light emitting diodes.

In the first project, we …

Heat And Mass Transfer In Parboiled Rice During Heating With 915 Mhz Microwave Energy And Impacts On Milled Rice Properties, Deandrae L.W. Smith

Graduate Theses and Dissertations

Microwave (MW) heating offers an energy-efficient, fast method to dry high moisture content (MC) parboiled rice to safe storage MC. However, there is limited research that describes the fundamentals of heat and mass transport in rice kernels exposed to MW energy at 915 MHz, the most promising heating frequency for industrialized processing. This information is vital to explain the implications of MW technology on dried rice quality. The overall objective of this study was to develop a microwave heating technology that can sufficiently dry high MC parboiled rough rice kernels in one pass using a 915-MHz industrial microwave system. An …

Nutritional Strategies For Feeding Broiler Breeders On Hen And Progeny Performance, Antonio Beitia

Graduate Theses and Dissertations

Over the last 60 plus years, broiler breeders have been under an incredible amount of genetic pressure. This genetic pressure comes from the continually increasing consumer demand for poultry products. The objective of this dissertation is to understand the effects of different nutritional and management practices on broiler breeder’s performance. The first series of experiments investigate the impact of broilerization on hen and early progeny performance. Broilerization is a process only used by genetic companies. The results from these experiments showed the adverse effects of broilerization on chick quality and hen performance. Follow up trials were performed to determine the …

Metatranscriptomics Analysis Of Ileum Microbial Communities In Necrotic Enteritis Chickens, Ruchita Uttarwar

Graduate Theses and Dissertations

Necrotic enteritis (NE) is a recognized multifactorial disease that causes an annual loss of $6 billion to the poultry industry. Thus, it has become essential to carry a comprehensive study of the composition of chicken gut which hosts this disease. The objective of this research is to measure the changes occurring in microbiome inside intestinal ilium of NE affected broilers which were treated with tributyrin supplement. This supplement is an anti-inflammatory metabolite that stabilizes intestinal integrity. The experimental design consisted of two challenge groups (No -Challenge, Clostridium Perfringens (CP) - Challenge) and one treatment group (tributyrin). To our knowledge, this …

New Flesh Cinema: Japanese Cyberpunk-Body Horror And Cinema As Catharsis In The Age Of Technology, Sarah Henry

Graduate Theses and Dissertations

This thesis provides a critical analysis of a specific group of films that combine the subgenres of cyberpunk and body horror which I call New Flesh Cinema. Films of this subgenre counter fears and anxieties of technological advancements by re-imagining the rise of technology and its societal effects as a transitional process through the illustration of literal and visceral depictions of the necessary alterations people will have to undergo in order to transition successfully into the new world. To contradict apocalyptic fears of advancing technology, these films offer a vision of a “New Flesh.” I argue the films share three …

Developing A High-Throughput Method To Screen Soybean Germplasm For Hypoxia Tolerance In Hydroponic Systems, Derrick Harrison

Graduate Theses and Dissertations

Soybean [Glycine max (Merr.)], the second most planted crop in the United States, is sensitive to field flooding due to depletion of oxygen and accumulation of CO2 in the rhizosphere. There is a need to breed cultivars that are adapted to areas prone to flooding, but field evaluations in the U.S. are limited because of time (one generation per year) and availability of resources (impermeable soils, irrigation, equipment to build levees). The purpose of this study was to develop and execute a protocol of germplasm screening for hypoxia tolerance using hydroponics in a controlled greenhouse environment. Germination rates and vigor …

Effect Of The Prospect Of Transport On Captive Tiger Behavior And Fecal Cortisol In Naïve And Experienced Tigers, Callan Lichtenwalter

Graduate Theses and Dissertations

With close to 5,000 captive tigers in the United States, it is vital to ensure that these tigers are receiving adequate welfare whether they are in an accredited facility, or privately owned. The goal of this study was to assess whether captive tigers at a rescue facility with experience being transported outside of the facility would respond differently to the presentation of their transport vehicle than their naïve counterparts who had only been transported within the facility. The behavior of 5 naïve and 7 experienced tigers (n = 12) located at Turpentine Creek Wildlife Refuge in Eureka Springs, Arkansas was …

The Effects Of Excess Dietary Sulfur Using Supplemental Sodium Sulfate On Beef Steer, Heifer, And Progeny Productive And Physiological Responses, Jamie Hawley

Graduate Theses and Dissertations

For studies 1 through 3, 20 steers of predominantly Angus breeding, were stratified by body weight (279 ± 13.2 kg), assigned randomly to 6 paddocks, and fed a low S ground corn and soybean meal supplement that did not contain any byproduct feeds (0.31% total dietary S; LS) or LS supplement with an additional 0.25% S provided from sodium sulfate (Na2SO4; 0.58% total dietary S; HS) for a 114-d growing phase. Steers were moved to feedlot (373 ± 0.2 kg), remained on prior dietary S treatments, and fed corn and soybean meal diets (0.19 and 0.42% total dietary S; LS …

Investigation Of The Role Of Heparin-Binding Pocket In Amyloid Fibrils Formation Of Fgf-1, I Gusti Ayu Agung Septiari

Graduate Theses and Dissertations

Human acidic fibroblast growth factor (aFGF/hFGF-1) is one of the promising molecules to be investigated to generate an in-depth understanding of the pathological mechanism of Alzheimer's disease (AD) neurodegenerative disorder characterized by the presence of amyloid fibrils. Some in vivo and human brain tissue studies proved the correlation of high-level expression of FGF-1-induced neuroinflammation and the occurrence of AD. The presence of amyloid fibrils as a hallmark of AD can be related to the generic property of the proteins to form amyloid fibrils; High level of FGF-1, in this case, may contribute to the formation of amyloid fibrils. As a …

Phenotypic Switching Of Bacterial Cells In Extreme Environments, Sudip Nepal

Graduate Theses and Dissertations

A large number of terrestrial microbial lives thrive in extremes of environmental conditions, including extremes of pressure, temperature, salinity, pH, and a combination of them. For example, all the marine biomass thrive at high hydrostatic pressure depending on depth. The temperature in the ocean can be very high near the hydrothermal vents and salinity and pH depends on the composition of salt in the surrounding areas. On the surface, hot springs, lakes and geysers provide high temperature conditions, while many places are permafrost regions with subzero temperatures. There is an emerging body of work on the viability, genomics, and metagenomics …

Remote Sensing And Gis Study Of Hazards And Risks In East Africa, Hafid Nanis

Graduate Theses and Dissertations

East Africa encompasses numerous developing countries and involves one of the most active continental rifts on Earth; namely, the East African Rift System. This region is prone to diverse geohazards due to its geographical location at the plate boundary. Several damaging events had happened across the region and more are predicted to occur in the near future. Therefore, it is crucial to investigate, assess, and forecast natural hazards and potential risks in the region. In this dissertation, remote sensing and Geographic Information System (GIS) were employed to conduct three independent studies focused on assessing geohazards in east Africa. Each study …

Correlation Analyses Among Soil, Plant, And Environmental Variables And Greenhouse Gas Emissions From Furrow-Irrigated Rice On A Silt-Loam Soil, Diego Della Lunga

Graduate Theses and Dissertations

Alternative water management practices for rice (Oryza sativa) production have been developed for water conservation purposes, such as the relatively new furrow-irrigated rice production system, which results in spatially variable volumetric water content (VWC), temperature, and oxidation-reduction (redox) potential. No research has been conducted to relate greenhouse gas (GHG) production to soil and plant properties or environmental factors under furrow-irrigated rice. The objective of this field study was to evaluate correlations between methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes and emissions and global warming potential (GWP) and near-surface soil properties and environmental factors over two growing seasons …

Introducing An Indigenous Non-Toxigenic Aspergillus Flavus Strain Isolated From Iraqi Corn Grains As A Bio-Control Agent To Reduce Aflatoxin Contamination In Corn Grains, Ali Almatakeez

Graduate Theses and Dissertations

Mycotoxin contamination of cereal crops, such as maize and sorghum, is a global concern because of the potential health effects on humans and animals. Although substantial research has been conducting regarding mycotoxin prevention and mitigation, little information is available about the association of mycotoxin-producing fungi with corn and sorghum grain in Iraq. Identifying and refining indigenous atoxigenic strains to reduce mycotoxin contamination of maize and sorghum has the potential to enhance the nutritional value of these grains while reducing economic losses. However, to our knowledge, this tactic has not yet been adopted by agricultural authorities and farmers in Iraq. To …

Far-Right Extremism In America: A Geospatial Analysis Of Incident Distribution, Meredith Leann Lerma

Graduate Theses and Dissertations

There has been little empirical research on the spatial relationship of violent far-right extremism. Previous studies have only focused on portions of far-right violent incidents, such as homicides, or amalgamated all far-right extremist activity, including legal incidents. This study uses data from the Extremist Crime Database (ECDB) and Southern Poverty Law Center (SPLC) in a temporal frame of 2000 to 2018 to test the relationship of violent incidents against geographic and social factors. The goal is to explore the relationships between macro-level factors and violent far-right extremist incident. The research determines that the presence of hate groups, higher immigrant populations, …

The Emotional Toil Of Paying For College: Lower Socioeconomic Status White Women’S College Experiences, 1880-1920, Heidi A. Jaeckle

Graduate Theses and Dissertations

Typically historical inquiries in higher education have been centered on privileged individuals from wealthier backgrounds who had the opportunity of attending primarily prestigious institutions. The experiences of college women from lower to middle class socioeconomic backgrounds have been for the most part ignored. This dissertation explores how socioeconomic backgrounds shaped the experiences of college women from the late nineteenth century to the early twentieth century, focusing on lower class students. With no universal financial aid program, the majority of these women were from families who could afford to pay tuition. Women from lower socioeconomic backgrounds did attend college, but their …

Structural Analysis Of The Multifunctional Spoiie Regulatory Protein Of Clostridioides Difficile., Blythe Emily Bunkers

Graduate Theses and Dissertations

Clostridioides (formally Clostridium) difficile is a medically relevant pathogen pertinent to infectious disease research. C. difficile is distinctly known for its ability to produce two toxins, enterotoxin A and cytotoxin B, and the propensity to colonize the mammalian gastrointestinal tract. It is known that metabolism is tightly correlated with sporulation in endospore producers such as C. difficile, but an interesting and novel regulatory relationship found by the Ivey lab has yet to be understood. The relationship explored in this study is observed between the sporulation factor, SpoIIE, which represses expression of an ABC peptide transporter, app. In this study, two …

Measuring Sexual Excitation And Sexual Inhibition In A Dutch-Speaking Sample, Malachi Willis

Graduate Theses and Dissertations

Background: Individual differences in sexual excitation and sexual inhibition are important predictors of sexual functioning. Psychometric instruments for these aspects of sexual response were originally developed separately for men (Sexual Inhibition /Sexual Excitation Scales [SIS/SES]) and women (Sexual Excitation/Sexual Inhibition Inventory for Women [SESII-W]). These measures were then adapted to function similarly in samples comprising both men and women (Sexual Inhibition/Sexual Excitation Scales-Short Form [SIS/SES-SF] and Sexual Excitation/Sexual Inhibition Inventory for Women and Men [SESII-W/M], respectively). No published study to our knowledge has administered the SIS/SES and SESII-W/M questionnaires to a sample of both women and men. In the present …

Earthworm Dynamics In Tallgrass Prairies In The Ozark Highlands Region Of Northwest Arkansas, Carlee Hensley

Graduate Theses and Dissertations

Tallgrass prairie was a historic and is presently a unique and endangered natural ecosystem throughout the Ozark Highlands region in the mid-southern United States. Tallgrass prairies have been disturbed for agricultural production and/or urban expansion; thus, as a result, efforts have been undertaken to reclaim areas previously used for agricultural production to mitigate the loss of tallgrass prairies. Limited research exists on earthworm dynamics in mounded tallgrass prairies or prairie restorations, particularly in the Ozark Highlands region of northwest Arkansas. The objectives of this study were to i) evaluate the effects of soil moisture regime (SMR; aquic and udic), landscape …

Effects Of Terrestrial Weathering On Rare Earth Element Concentrations And Sulfur Isotopic Signatures Of Carbonaceous And Ordinary Chondrites, Ruby Virginia Patterson

Graduate Theses and Dissertations

Understanding the effects of weathering of chondrites is essential to gaining accurate and useful information about the formation of our solar system, as well as a more detailed account of the mobilization of chondritic compounds when they encounter terrestrial conditions. Elemental concentrations and stable isotope analyses of chondrites, considered to be the most primordial material in the solar system, are two tools which help unlock the weathering patterns of these specimens when they enter the earth system. However, it is not currently known exactly how time spent in the field alters rare earth element (REE) concentration or δ34S signatures within …

Genetic Architecture Of Salt And Drought Tolerance In Cowpea, Waltram Second Ravelombola

Graduate Theses and Dissertations

Cowpea [Vigna unguiculata (L.) Walp.] is a diploid and nutrient-dense legume species. It provides affordable source of protein to human. Cowpea cultivation is prevalent in Africa, Asia, the western and southern U.S., and Central and South America. However, earlier reports have shown that drought and salt stress can be devastating to cowpea production. The objectives of this study were to screen for salt and drought tolerance in cowpea and to identify molecular markers associated with these traits. Simple methodologies to screen for drought (Chapter 2) and salt tolerance were developed (Chapter 3). Results suggested that: 1) a total of 14, …