Digital Commons Network^™

Economic And Ecosystem Impacts Of Gm Maize In South Africa, Kristiina Ala-Kokko

Graduate Theses and Dissertations

White maize in South Africa is the only staple crop produced on a widespread commercial basis for direct human consumption using genetically modified (GM) cultivars. Using a combined economic and environmental approach, we estimate the total welfare benefits attributable to GM white maize in South Africa for 2001-2018 are $694.7 million. Food security benefits attributable to GM white maize in South Africa also manifest through an average of 4.6 million additional white maize rations annually. To achieve these additional annual rations using conventional hybrid maize, the additional land required would range from 1,088 hectares in 2001 to 217,788 hectares in …

Resistance Screening And Association Mapping For Resistance To The Downy Mildew Pathogen Of Spinach, Dotun Olaoye

Graduate Theses and Dissertations

Spinach is an important cool leafy vegetable cultivated around the world, with large scale production in California and Arizona in the U.S. Spinach is a highly nutritious vegetable beneficial in the human diet. Spinach is affected by a number of biotic stressors. Downy mildew, caused by the oomycete pathogen Peronospora effusa, is a major threat to spinach as it affects the leaf quality and impacts the economic value of spinach. Several efforts have led to the development of resistant genotypes/cultivars to this pathogen. However, few studies have examined the genetics of resistance to the downy mildew pathogen in detail. This …

Optimization Of Broken Rice Consumption Through Understanding The Confluence Of Sensory And Economic Preferences, Matthew Greer Richardson

Graduate Theses and Dissertations

The authors were perplexed by the seeming dichotomy between the majority 70% of Haitian consumers being chronically food insecure, but still preferring to pay premium international market prices for long-grain rice that constitutes 30% of the calories in this poorest nation in the Western Hemisphere. The aim of this study was to determine the optimal percent broken rice in regards to price specifically to Haiti. Optimization between quality and price point is seen as the best rice for the price, and can be found through combining individual preferences with willingness to pay. Broken rice (brokens) garner a significantly discounted price …

Starter Nitrogen Source And Preflood Nitrogen Rate Effects On Rice Grown On Clay Soils, Linda Rachelle Martin

Graduate Theses and Dissertations

Seedling rice (Oryza sativa L.) grown on clayey-textured soils generally develops slowly as compared to loamy-textured soils. Our research examined the effects of starter-N source and preflood-N rates on canopy closure, total aboveground N uptake, and grain yield of rice grown on clayey-textured soils. Eleven field trials were established in Arkansas and Mississippi including five trials with a hybrid cultivar and six trials using a pure-line cultivar. Starter-N sources included no starter-N (NONE), ammonium sulfate (AMS), diammonium phosphate (DAP), and urea (UREA) applied at 24 kg N ha-1 at the rice 2-leaf stage and five preflood-N rates ranging from 0-224 …

I Matter: Understanding The Self-Care Practices Of School Counselors During The Covid-19 Pandemic And How Internal And External Factors Create Barriers, Alisha Rene Marie Jones

Graduate Theses and Dissertations

Diminished self-care practices and heightened stress of school counselors is a continuing problem in education. With role ambiguity, high student-to-counselor ratios, emotional exhaustion, and others adding pressure to the roles and responsibilities of school counselors, this study investigated the self-care practices of Missouri school counselors and the internal and external factors which influence them, specifically within the context COVID-19. Clayton Alderfer’s (1972) Existence, Relatedness, and Growth theory was used as a theoretical framework for chosen self-care practices represented in this study and was supported by Robert Kegan’s and Lisa Lahey’s (2009) Immunity to Change theory to understand the competing commitments …

Peptoid-Based Microsphere Coatings For Biomaterial Applications, Jesse Leland Roberts

Graduate Theses and Dissertations

Peptoids are peptidomimetic oligomers that predominantly harness similarities to peptides for biomimetic functionality. The incorporation of chiral, aromatic side chains in the peptoid sequence allows for the formation of distinct secondary structures and self-assembly into supramolecular assemblies, including microspheres. Peptoid microspheres can be coated onto substrates for potential use in biosensor technologies, tissue engineering platforms, and drug-delivery systems. They have the potential for use in biomedical applications due to their resistance to proteolytic degradation and low immunogenicity. This dissertation focuses on the physical characteristics and robustness of the peptoid microsphere coatings in various physiological conditions, along with their ability to …

Evaluation Of Nutritional Factors That Influence The Efficacy Of Tributyrin As A Feed Additive For Broilers, Brooke Bodle

Graduate Theses and Dissertations

Tributyrin (TB) is a glyceride ester of butyrate that has the potential to improve broiler performance and intestinal development. Therefore, to fully evaluate this potential, three experiments were conducted to evaluate effect of tributyrin (TB) on broiler growth performance, nutrient digestibility, carcass characteristics, intestinal morphology, and gastrointestinal function in birds fed diets varying in composition reared in battery cages and floor pens. Experiment 1 explored the supplementation of graded doses of TB and its impact upon growth performance, nutrient digestibility, and carcass characteristics in a step-down program when added to a reduced energy and amino acid diet. A linear reduction …

Beautiful People: The Past, Present, And Future Of The Fashion Industry's Thin Ideal, Shane White

Graduate Theses and Dissertations

Negative body image among women has become an extremely relevant topic in the last decade. The “ideal” female body image and what a person should look like according to marketing and advertising has become a highly controversial issue. This project seeks to show how the fashion industry has, over centuries, shaped how people think they need to look and in today’s time and show how it has been a root cause of issues like body image complexes leading to negative self-perception, eating disorders, mental illnesses like anxiety, depression and addiction, and even suicide. Over the last three to four decades, …

Impact Of Different Plant-Based Foods Consumption On The Composition And Diversity Of Gut Microbiota, Ayoub Al Othaim

Graduate Theses and Dissertations

Plant-based diets are primarily derived from plant sources, including fruits and vegetables. Such patterns are associated with health benefits by promoting general health and preventing many diseases and metabolic disorders. Fruits and vegetables are key sources of high-quality nutrients such as dietary fibers and polyphenols. Since they are rich in dietary fibers and polyphenols, whole fruits and vegetables represent unique and somewhat understudied modulators of the gut microbiota and its associated functions. This study aims to (i) investigate the impact of varying dilutions of cherry juices concentrate on the composition of the murine gut microbiota, (ii) investigate the impact of …

Description Of Job Embeddedness In Arkansas County Extension Agents, Anika Parks

Graduate Theses and Dissertations

The Cooperative Extension System (CES) has had a long-standing problem with the retention of its county Extension agents (CEAs), who are in charge of running various programs in over 3,000 counties within the United States. When a CEA leaves a county, voluntarily or involuntarily, the community members are left without that leader, and their needs go unmet, which was proposed to increase voluntary turnover among CEAs even further. Arkansas CES has had its problems with turnover, and studying this issue through the lens of Job Embeddedness Theory was identified as a gap in the literature.

Job Embeddedness Theory is a …

Pathogenicity Of Staphylococcus Agnetis Associated With Lame Broilers With Osteomyelitis, Sura Faris Salih Zaki

Graduate Theses and Dissertations

We developed High Resolution Melt Analysis (HERMA) as a rapid and reliable molecular diagnostic assay for the detection and identification of the main bacterial species recovered from the blood and lesions of bacterial chondronecrosis with osteomyelitis (BCO) from the lame broilers at the University of Arkansas poultry research farm. Also, the present study confirms that raising young birds on suspended wire flooring has been proved to successfully induce lameness attributable to BCO with birds being more susceptible to bacteraemia than those that were raised on litter flooring. The newly described pathogen, Staphylococcus agnetis, has been reported to be overrepresented in …

Identifying Effective Teaching And Recruitment Strategies Used By Efnep In Reaching Limited Income Audiences In The United States, Alexandria Mcleod

Graduate Theses and Dissertations

The two articles presented in this thesis used a researcher-developed literature-based survey instrument to collect data on the Expanded Food and Nutrition Education Program (EFNEP) in the United States. Data was collected on methods of teaching, communication technologies used, recruitment strategies, barriers to attending classes, and program assistant demographic data. There were 803 program assistants working during the 2018-2019 program year. There were 346 program assistants who completed the 35-question survey instrument during data collection.

The first article focused on identifying effective teaching strategies used to increase program engagement by collecting data on program characteristics, methods of teaching, and educational …

Economic Feasibility Of Sub-Surfaced Poultry Litter, James Timothy Stults

Graduate Theses and Dissertations

Livestock producers routinely spread fertilizer or broadcast poultry litter to improve forage production. With poultry litter widely available across the Southeastern United States and a cheaper source of plant nutrition than fertilizer when proximal to application sites, the novel application of litter below the soil surface, while costly, allows for greater nutrient retention than broadcasting. Since quantifying costs and benefits of sub-surface litter application (SSLA) is complex, we develop and present a spreadsheet tool for automated comparison between SSLA, fertilizer, and broadcasted litter for user-specific scenarios involving equipment choices (new, used, custom), desired nutrient needs for crops grown, litter nutrient …

Quality Determinates Of Rice Price In Open Bag Markets In Sub-Saharan Africa, Bailey Peterson-Wilhelm

Graduate Theses and Dissertations

Weaknesses in the grades and standards system in low-income countries across Sub-Saharan Africa undermine the transparency of agricultural markets. In the Democratic Republic of the Congo (DRC), Ghana and Mozambique rice is predominately sold in open bags and if rice price does not reflect its quality, then inefficiencies may lead to consumer welfare losses. Importantly, it is possible that impoverished communities are priced out of the market due to inflated and inefficient prices. The objective of this study is to examine determinates of rice price by estimating the impact of selected rice quality attributes on rice prices in DRC, Ghana …

The Impact Of Mindfulness On Healthy Food Choices, Kaylea Hopfer

Graduate Theses and Dissertations

The practice of mindfulness has a long history in research, particularly psychological studies. In this paper I examine the effects of a short mindfulness intervention on healthy food purchases. Specifically, I developed an online survey and recruited 634 participants via Prolific between July 24 - July 27, 2020. I randomly assigned participants to either a mindfulness manipulation or a control condition. Following treatment (or control) participants completed a food choice task and various other control. Following the survey, I analyzed data using R version 4.0.2 (2020-06-22) and R-Studio. I estimated three different regression models, ordinary least squares (OLS), Poisson, and …

Methods To Reducing Weaning Stress In Early Weaned Spring Beef Calves, Matthew Daniel Hahn

Graduate Theses and Dissertations

Reducing weaning stress in beef calves can have dramatic benefits to the health, growth, and performance to beef calves post-weaning. Studies have shown that providing creep feed to calves during the pre-weaning period can improve their nutritional status, which can better prepare them for the stresses they will be exposed to during the weaning process. Studies have also shown that two-stage weaning can reduce the stresses associated with weaning. Previous research has suggested that this method resulted in dramatic changes in behavioral signs associated with stress. The objective of this study was to evaluate the effects of two-stage weaning with …

Relationship Of Underline Scores And Production Traits In Beefmaster Cattle, Bryan R. Kutz

Graduate Theses and Dissertations

The objective of this study was to establish the relationship of underline scores (UDLS), production traits, and conformation scores in Beefmaster cattle born between 1976 through 2008. Records provided by Beefmaster Breeders United (BBU) were analyzed. Certified classifiers approved by the BBU recorded scores. Sizes and shapes of the underlines differentiated the scores (1-4). A score of one was used to designate the least amount of navel flap or sheath and a score of four represents the maximum amount of naval flap or sheath accepted for registration in the BBU. In this study the relationship of the traits was determined …

Sex-Based Differences In Acvr2b And Grb10 Expression In Skeletal Muscle During Induced Cancer Cachexia And Disuse, Lauren Martinez

Graduate Theses and Dissertations

Background: Muscle atrophy is the shrinkage of muscle fibers that are largely maintained by a balance of protein synthesis and degradation. Imbalances in protein synthesis and degradation are observed in different muscle atrophy disorders such as cancer cachexia and disuse. These forms of muscle atrophy produce distinct wasting pathologies that are influenced by biological sex. Activin receptor type-2B (ACVR2B) and Growth factor receptor-bound protein 10 (GRB10) have been identified as genes that potentially regulate muscle mass while also displaying sexually dimorphic differences. Purpose: To examine the influence of ACVR2B and GRB10 throughout the development of cancer cachexia and disuse-induced atrophy …

Quantifying The Leaching Of Nutrients And Metals In A Pasture Soil As Affected By Excreta Of Ruminants Fed Alternative Diets, Ian Kennedy

Graduate Theses and Dissertations

The leaching of nitrate through the soil profile and into adjacent water systems has been a leading cause of water pollution and results in the loss of a valuable nutrient from animal production systems. Forage-based animal production systems may be improved through manipulation of animal diets that incorporate tannins and total polyphenolic compounds with feed, increasing the amount of nitrogen (N) retained by an animal/decreasing rates of digestion and altering the N-containing compounds that are excreted and deposited onto soil. Incorporating the forage legumes sericea lespedeza (Lespedeza cuneate [Dumont de Courset] G. Don) and lablab (Lablab purpurues L.) into the …

Assessment Of Meat Quality Attributes Of Four Commercial Broiler Strains Processed At Various Market Weights, Ashleigh Jo Mueller

Graduate Theses and Dissertations

As the demand for poultry meat continues to grow, the industry is challenged with how to meet these needs of consumers. The growth rate of broilers is continuously improving in order to increase production efficiently resulting in greater yields and an increase in product to satisfy consumer needs. However, the industry has seen an increase in quality issues of the meat as growth rates and growth periods continue to increase. The objective of this study was to evaluate the effect of various strains (standard and high-yielding) and target weights on meat quality attributes such as pH, water holding capacity (WHC), …

The Varied Thermal Response Of Magnetic Iron-Oxide Nanoparticles During Induction Heating In Liquid And Solid-Liquid Phase Change Mediums, Joshua Tompkins

Graduate Theses and Dissertations

This study investigates the induction heating response of uncapped iron oxide nanoparticles sonically dispersed as a nanofluid and mechanically distributed in solid phase change materials. The nanoparticles examined have a mean diameter of 14.42 nm and are magnetically heated in an alternating magnetic field at an amplitude of 72.6 kA/m at frequencies of 217, 303, and 397 kHz. Nanoparticle characterization was undertaken through transition electron microscopy, x-ray diffraction, and dynamic light scattering when in suspension. Carrier fluids were characterized through viscosity, heat capacity, and density measurements which were used in the calorimetric calculation of the specific absorption rate (SAR) of …

Implications Of Lysine Acetylation On The Enzymes Of The Tca Cycle, Sumana Venkat

Graduate Theses and Dissertations

The tricarboxylic acid (TCA) cycle is a central route for the energy production via oxidative phosphorylation and is ubiquitous throughout nature. Apart from playing a major role in energy provision, it is also essential for a wide range of physiological functions in any organism. Although an increasing emphasis is laid on the interlinking role of the cycle, its regulation and control are less very less understood. As the field progresses, the consequences of TCA cycle anomalies are shown to be tied to various cancers and other disorders. The matter becomes more complex when considering the varying functions of the isozymes …

Dietary Regulation Of Successful Aging, Aubree L. Hawley

Graduate Theses and Dissertations

The current growth of the older population is unprecedented in U.S. history. Chronic disease and functional limitation commonly develop prior to old age, leading to prolonged physical disability and decreased well-being. The development of chronic disease and loss of independence is associated with lean body mass (LBM) loss and fat mass gain beginning in middle age. Therefore, it is important to identify modifiable factors to mitigate deleterious shifts in body composition to promote successful aging (SA). The concept of SA is associated with longevity, the absence of disease and disability, and subjective components of well-being, however, an operational definition has …

Impacts Of Postharvest Temperature Exposure Profiles On Rice Physicochemical Properties, Seth Graham-Acquaah

Graduate Theses and Dissertations

Heated-air drying followed by tempering (HAT) is effective for increasing rough-rice drying rates without compromising head rice yield (HRY). However, heat exposure could affect rice end-use properties. Hypothesizing that the total amount of heat exposure incurred by rice during heated-air drying determines the trend and magnitude of changes in end-use properties, this dissertation sought to 1) characterize the effects of drying and tempering regimen on changes in end-use properties, 2) derive an index to quantify and compare the amount of heat exposure that rice kernels incur during active drying and, 3) relate values of this index to changes in rice …

Application Of X-Ray Imaging And Glass Transition Principles In Understanding Rice Kernel Fissure Formation, Zephania R. Odek

Graduate Theses and Dissertations

Rice kernels with internal fractures of the endosperm, fissures, tend to break during milling, leading to head rice yield (HRY) reductions. Minimizing kernel fissuring is thus an important goal of the rice industry. To minimize fissuring during the drying process, a better understanding of the fissuring process and the kinetics thereof is required. The goal of this research was to use X-ray imaging and glass transition principles to better understand rough rice kernel fissuring. First, because the instance when the fissuring process is initiated and completed during the drying process is not well known, an X-ray imaging setup that allows …

Molecular Genetic Analysis Of Drought Resistance And Productivity Traits Of Rice Genotypes, Yheni Dwiningsih

Graduate Theses and Dissertations

Rice (Oryza sativa L.) is the staple food for a majority of the world’s population, and uses 30% of the global fresh water during its life cycle. Drought at the reproductive stage is the most important abiotic stress factor limiting grain yield. The United States is the third largest exporter of rice, and Arkansas is the top rice-producing state. The Arkansas rice-growing region in the Lower Mississippi belt is among the 10 areas with the highest risk of water scarcity. Adapted U.S. rice cultivars were screened for drought resistant (DR) traits to find sources for breeding U.S. rice cultivars for …

Anti-Inflammatory Properties Of Blackberry Phenolic And Volatile Compounds, Pauline Morin

Graduate Theses and Dissertations

Berries are known for many health benefits including anti-inflammatory properties that lower risks of chronic diseases. These properties have been linked to high concentrations of phenolic compounds, especially anthocyanins. However, the present study hypothesized that volatiles could contribute to the berries’ bioactive properties. Thus, the objectives of this research are to profile the phenolic and volatile composition of 16 blackberry genotypes harvested at the Fruit Research Center of the University of Arkansas and to evaluate the antiinflammatory capacities of three selected genotypes on inflamed cells. Phenolic and volatile profiles were evaluated using chromatographic techniques. The three genotypes A2528T, A2587T and …

Effect Of Feed Additives And Toxic Elements On Swine Growth Performance, Nutrient Digestibility, Immune Function And Reproductive Performance, Richard A. Mudarra Hernández

Graduate Theses and Dissertations

To evaluate the effects of peptide in combination of zinc oxide (Zno) or acidifiers (Exp 1), and gossypol (G) from cottonseed meal (CSM) ( Exp 2&3) on growth performance, complete blood cell counts (Exp 1, 2&3), nutrient digestibility (Exp 1), plasma gossypol (Exp 2&3) and semen quality (Exp 3), weaned pigs (Exp 1), growing gilts (Exp 2) and growing boars (Exp 3) were randomly allotted to dietary treatments. Treatments for Exp 1 during phase 1&2 were: (1) Positive Control (PC), formulated to meet NRC (2012) nutrient requirements; (2) Negative control (NC), fish meal was reduced to achieve -0.13% SID lysine; …

Effects Of Commercial Feed Additives On Growth Performance And Gut Microbiota Of Nursery Pigs, Xiaoyuan Wei

Graduate Theses and Dissertations

To secure animal welfare and maximum production, feed additives are often added to nursery pig diets to increase nutrition digestibility, enhance intestinal health, and prevent or mitigate disease, with the ultimate goal of improving growth performance. This thesis performed a longitudinal analysis using next-generation sequencing to investigate the dynamic changes of gut microbiota in weaned pigs fed commercial feed additives. Chapter II was used to evaluate the effects of organic acid mixture on growth performance and gut microbiota of weaning pigs. This study demonstrated that the inclusion of 0.035% (SBA0.035) or 0.070% (SBA0.070) sodium butyrate in a diet containing 0.5% …

Association Mapping For Soybean (Glycine Max L. Merr.) Protein And Oil Content, Joseph Najjar

Graduate Theses and Dissertations

Soybean [Glycine Max (L.) Merrill] is an important economic crop because of its high content of seed protein and oil. Seed oil and protein content are quantitative inherited traits. The genetics of seed protein and oil levels have been extensively studied, with 367 QTL reported for protein and 475 QTL reported for oil to date. Validation of such QTLs, and identification of easily-automatable molecular markers around these QTL will aid the progression of breeding for such traits. The focus of this research was to discover novel and verify previously reported QTL related to protein and/or oil content via Genome-Wide Association …