Life Sciences Commons^™

Evaluation Of Factors That Contribute To Injury To Quizalofop-Resistant Rice From Quizalofop Applied Postemergence, Navdeep Godara

Graduate Theses and Dissertations

Quizalofop-resistant rice technology allows for over-the-top applications of quizalofop, an acetyl-coenzyme A carboxylase-inhibiting herbicide. However, quizalofop caused significant injury to quizalofop-resistant rice in some Arkansas fields during the first year of commercialization. Experiments evaluated the effect of early-season soil moisture and nitrogen availability; pre-exposure to low rates of glyphosate and imazethapyr; planting date; and environmental conditions including, soil moisture content, air temperature, and light intensity on quizalofop-resistant rice tolerance to quizalofop applications. All experiments assessed sequential quizalofop applications made to 2-leaf followed by 5-leaf stage of rice. Sequential quizalofop applications alone and with surface irrigation or nitrogen application at the …

Histomonosis In Turkeys – Factors Influencing Transmission, Pathogenesis, And The Search For Prophylactic Or Therapeutic Compounds, Thainá Landim De Barros

Graduate Theses and Dissertations

The incidence of histomonosis has been increasing in poultry since the ban of prophylactic and therapeutic compounds. Histomonosis is caused by the protozoa Histomonas meleagridis. The objective of this dissertation was to investigate factors impacting the pathogenesis and transmission of histomonosis and to evaluate compounds that could potentially prevent or reduce the severity of histomonosis in turkeys. In the first study, the effect of sodium chlorate and sodium nitrate on reducing histomonads growth was tested in vitro and added to a basal turkey diet. A decrease in the growth of histomonads in vitro was observed, but no in vivo effect …

Sex Differences In Cancer Cachexia And A Novel Mitochondrial Target For Cancer-Induced Muscle Wasting, Seongkyun Lim

Graduate Theses and Dissertations

Cancer cachexia (CC) is a devastating wasting syndrome characterized by marked weight loss including skeletal muscle atrophy that affects approximately 80% of cancer patients. Current therapeutic treatments including pharmacological and nutritional intervention are insufficient to prevent or reverse it. Prior studies demonstrated lower muscle mass, impaired muscle function, and mitochondrial health in the development of CC. Specifically, mitochondrial fusion protein, Optic atrophy 1 (OPA1) which plays a significant role in skeletal muscle health, is suppressed in the development of CC. Furthermore, most pre-clinical CC studies were mainly focused on males although there are distinct phenotypical differences in skeletal muscle between …

The Effects Of Physical Function And Genetics On Cognition And Blood Biomarkers In Individuals At-Risk For Alzheimer’S Disease And Related Dementias, Joshua Louis Gills

Graduate Theses and Dissertations

Alzheimer’s disease and related dementia (ADRD) rates are expected to triple by the year 2050. Early detection and specific mitigation efforts are warranted to blunt the alarming rate. Physical function (PF) declines with age, but higher physical function is associated with better cognitive functioning in middle-to- older age individuals. Moreover, greater physical activity (PA) is associated with better global cognition; however, Apoliporotein e4 carriers may not gain the same benefits with exercise. Additionally, plasma phosphorylated tau 217 (p-tau217) has been identified as a novel diagnostic ADRD biomarker which needs further research to examine associations with risk factors. Therefore, the aims …

The Role Of Temperature Variation On Macrophage Physiology And Function In Vitro In Mice, Chicken, And Fish, Intisar Abdullah Hassan

Graduate Theses and Dissertations

Fever is an essential component of the immune response. Baseline body temperatures vary in different species, and fever represents increased temperature over baseline. Fever initiates and enhances immune responses as well as creates an environment in which the body has advantages over pathogens. Macrophages are often the first line of cells that come in contact with pathogens, asthey reside in and traffic through tissues. They are important for their engulfment of pathogens that results in the digestion of the pathogen, and they also produce nitric oxide and cytokines that contribute to immune responses in a variety of ways, including initiating …

A Cross-Scale Nexus: Microbial Functional Genes In Tandem With Molecular-Level Nitrogen Fluxes And Implications For Field-Scale Biogeochemical Processes, Srusti Maddala

Graduate Theses and Dissertations

Nitrogen (N) biogeochemical cycling entails close networking between soil nutrients, plant species and resulting microbial communities, and abiotic factors such as temperature, moisture, and pH. To better understand transformations of N in soil microsites, which are known to be rich in N-cycling behavior, the microdialysis technique was employed to generate in situ data on temporal alterations of N during wetting-drying conditions in both the field and laboratory. The objectives were to 1) determine the lifespan of the microdialysis technique in field conditions, 2) evaluate the ability of the method to yield N fluxes that would be differential between the two …

Discrete Choice Experiments In Agricultural And Food Economics: Two Essays On Information Provision Modalities, Uncertainty Adjustment, And Hypothetical Bias, Monsoïa Arsène Juste Agossadou

Graduate Theses and Dissertations

Stated discrete choice experiments are extensively used in applied economics to study preferences and valuation for new products, as well as costs and benefits of new policies and programs. Moreover, information provision experiments widely use the method to examine information effects on different outcomes. This thesis explores two methodological issues in discrete choice experiments: (i) information provision modalities and (ii) hypothetical bias. The first study examines the effect of information modality by testing the effect of using combined text script and audio clip (treatment) versus only text script (control) to convey information in discrete choice experiments. Specifically, the study elicits …

The Role Of Microbiota On Campylobacter Jejuni Colonization And Growth Performance In Broiler Chickens, Ayidh Almansour

Graduate Theses and Dissertations

The successful poultry production at modern era comes from the vertical integratedindustrialization, which has fundamentally changed how animals have been living for millions of years. Antimicrobial growth promoters have been used to sustain the efficient industrialized animal production, driving antimicrobial overuse and resistance. Because of the increasing pressure from consumer’s concerns and government regulations, it is urgent to develop antimicrobial free alternatives as growth promoters in poultry production, but few effective antimicrobial alternatives are currently available. Campylobacter jejuni is one of the worldwide prevalent foodborne bacterial pathogens mainly transmitted from poultry. However, few mechanisms are available on why C. jejuni …

Hiding In Plain Sight: Accounting For Rate Heterogeneity In Trait Evolution Models, James Boyko

Graduate Theses and Dissertations

Within the last four decades, phylogenetic comparative methods have become the defacto method of analysis for comparative biologists. The availability of high-quality comparative datasets has been matched by an explosion of possible phylogenetic models. In large part, the efforts to increase the realism of phylogenetic comparative methods has been successful as evidenced by their widespread use. To this extensive literature, my contributions are modest. I have focused my dissertation work on two main themes. First, most phenotypic evolution is not independent of other phenotypes. Changes in a particular character may influence changes in another and modeling these characters in isolation …

Identification Of Genomic, Proteomic, And Metabolomic Signatures Associated With Pulmonary Hypertension Syndrome In Broilers, Duaa Almansaf

Graduate Theses and Dissertations

The present dissertation contains a collection of studies that examine the genomic, proteomic, and metabolomic association to pulmonary hypertension or ascites phenotype in fast-growing broilers. Pulmonary hypertension is a multifactorial metabolic disease influenced by physiological, environmental, and nutritional factors. It is characterized by a number of structural changes including, thrombosis and adverse pulmonary vascular remodeling. Thus, the atrial pressure is increased, and the right ventricle becomes hypertrophied, resulting in heart failure and the death of the bird. Pulmonary hypertension or ascites is a global problem that has negatively impacted the economy. The increased mortality rate of broilers (25%) is estimated …

Investigating Hops Production In Arkansas To Support Specialty Crop Growth, James Oliver Mcclellan

Graduate Theses and Dissertations

The hop plant (Humulus lupulus L.) is a perennial, climbing species within the Cannabaceae family that produces cones used for brewing. Hops are grown worldwide. In the United States most hops production occurs in the Pacific Northwest, but growth in the craft beer industry is driving efforts for hops production in other U.S. regions. Recommendations on hops cultivar suitability, fertility, and management are needed for the U.S. mid-south region. Objectives of this research on Arkansas-grown hops were to 1) assess the impact of cultivar and fertility rate on plant and cone attributes of six cultivars of Arkansas-grown hops and 2) …

Habitability, And Evolution Of Microorganisms Under Extreme Conditions, Azarin Yazdani

Graduate Theses and Dissertations

The choice of a solvent determines the possible biochemistry of life. Life on Earth is based on carbon biochemistry and has evolved in an environment with water as a solvent. As a polar solvent abundant on Earth, water has unique physical properties, including a large range of liquidity and low viscosity, making it a very good solvent for terrestrial life. Liquids other than water are abundant in the universe, and the chemical nature of these liquids might lead to different chemistries of life. In the first chapter, we review the main characteristics of a good solvent, and then we use …

Riverscape Community Genomics Of Ozark Fishes: A Comparative Framework To Infer Ecological And Evolutionary Determinants Of Genetic Diversity, Zachery D. Zbinden

Graduate Theses and Dissertations

Genetic variation is a crucial component of biodiversity and represents the variability and spatial structure of alleles within and among organisms. Evolution modulates this variability over time through mutation, selection, gene flow, and genetic drift. However, our capacity to test foundational theories of population genetics has always been at the mercy of molecular approaches available to quantify patterns of genetic diversity. Initially, techniques for empirical DNA studies were in their infancy and limited by technologies and the price per unit of genetic information. Because of these constraints, our pursuits have generally been limited to investigations of one or a few …

Conservation Of Open-Canopy-Associated Wildlife: Multi-Scale Management Impacts On Imperiled Herpetofauna, Ethan Joseph Royal

Graduate Theses and Dissertations

The loss of open-canopy ecosystems throughout North America has precipitated declines in reptile and amphibian species associated with these habitat types. Current efforts to restore open-canopy ecosystems are underway in many areas, but the local distributions of, habitat characteristics required by and the effects of management actions on many herpetofauna species are poorly understood or entirely unknown. Research examining relationships among herpetofauna and their environments is often complicated by the extremely low detectability seen in many studies. We used landscape-scale, assemblage-level surveys to investigate the occupancy patterns and habitat associations of open-canopy-associated herpetofauna in two regions, as well as gain …

The Relationship Between Psychosocial Factors And Food Waste-Related Behaviors Among College Students, Kacy Raquel Wright

Graduate Theses and Dissertations

Food waste is a significant environmental, economic, and social issue, with younger consumers as the most significant contributors. Specific behaviors, like over-purchasing food and misusing date labels, result from a complex interaction between social and psychological factors, which influence food waste among this demographic. The purpose of this study was to identify the psychosocial factors influencing food waste behaviors among college students at the University of Arkansas. Guided by the Theory of Planned Behavior, this study utilized online and face-to-face quantitative surveys, distributed to students enrolled at the University of Arkansas in the spring of 2022. Demographics, attitudes, subjective norms, …

Evaluating Flavor And Aroma Attributes Of Arkansas-Grown Horticultural Crops, Jordan Chenier

Graduate Theses and Dissertations

Arkansas has a climate and geography that allows for the production of unique horticultural crops, including hops (Humulus lupulus L.), blackberries (Rubus subgenus Rubus), and muscadine grapes (Vitis rotundifolia). These crops not only have potential for growers in Arkansas but have unique flavor and aroma attributes that impact marketability. Volatile compounds present in many different agricultural plants are the primary source of biologically-derived aromas and flavors. Therefore, the volatile and other quality attributes of hops, blackberries, and muscadine grapes were evaluated at the University of Arkansas (UA System) Division of Agriculture. The quality, volatile, and sensory attributes of four hops …

Modeling The Impact And Accelerating The Process Of Transitioning To A Sustainable Healthy Diet Through Decision Support Systems, Prince Agyemang

Graduate Theses and Dissertations

Food production and consumption are essential in human existence, yet they are implicated in the high occurrences of preventable chronic diseases and environmental degradation. Although healthy food may not necessarily be sustainable and vice versa, there is an opportunity to make our food both healthy and sustainable. Attempts have been made to conceptualize how sustainable healthy food may be produced and consumed; however, available data suggest a rise in the prevalence of health-related and negative environmental consequences of our food supply. Thus, the transition from conceptual frameworks to implementing these concepts has not always been effective. This paper explores the …

Characterization Of Blueberry (Poly)Phenolics In Foods, Their Metabolites In Human Biological Samples And Anti-Inflammatory Effects Of Phytochemicals In Vitro, Laura Felgus-Lavefve

Graduate Theses and Dissertations

Blueberries’ popularity is in part supported by the health benefits associated with their consumption. Research has strongly focused on their polyphenol and anthocyanin concentration, one of the highest amongst commonly consumed foods. Polyphenols have demonstrated antioxidant effects in vitro, and consuming polyphenol-rich foods is associated with protective effects towards non-communicable diseases, but their direct bioactivity in the human body remains to be fully understood. It is estimated that about 90 to 95% of the initial polyphenol intake reaches the colon without being absorbed. Instead, phenolic compounds go through extensive biotransformations, consisting of catabolism into smaller compounds mostly carried out by …

Using Condensed Tannin To Mitigate Tall Fescue Toxicosis, Ally Jo Grote

Graduate Theses and Dissertations

Endophyte-infected (Neotyphodium coenophialum) tall fescue, [Schedonorus arundinaceus (Shreb.)] produces ergot alkaloids. Condensed tannins could bind to ergot alkaloids and render them ineffective. The first objective was to improve the health of sheep offered endophyte-infected tall fescue by binding toxins in the rumen with condensed tannins. Non-toxic novel-endophyte infected tall fescue (NE) or toxic endophyte-infected tall fescue forage was harvested, baled at targeted moisture of 55%, wrapped within 8 hours of baling with 2 layers of net wrap and 20 layers of plastic, and ensiled for at least 60 days. Prior to feeding, forages were chopped and packed into plastic trash …

Application Of Microwave-Assisted Technology For Single-Pass Drying Of Rough Rice, Rebecca Mawusi Bruce

Graduate Theses and Dissertations

The 915 MHz industrial microwave is a novel technology that has the potential to achieve one-pass drying of rice within a short drying duration and reduce rice drying losses. However, processing recommendations for the commercialization of this technology for rice drying is lacking. The goal of this research is to provide processing conditions that are useful for the commercialization of the 915 MHz industrial microwave technology for rice drying. This was achieved by studying the impact of microwave specific energy and processing conditions such as harvest moisture content, milling duration, and aging on the physicochemical properties of a 915 MHz …

Allelopathic Effect Of Cereal Straw Extracts On Growth Of Raphidocelis Subcapitata And Microcystis Aeruginosa, Holly Wren

Graduate Theses and Dissertations

Harmful algal blooms are increasing in size, duration, and intensity around the globe. For several decades, cereal straws have been recognized as a viable algal control method, though the mechanisms by which cereal straws inhibit algae remain a topic of research. The objectives of this study were to evaluate the effectiveness of decomposing cereal straw extract, particularly rice (Oryza sativa) and barley (Hordeum vulgare) straw extract, to inhibit the green alga Raphidocelis subcapitata or cyanobacteria Microcystis aeruginosa in bioassays and to determine if the effectiveness of decomposing rice straw extract is altered by the presence of natural organic matter or …

Chondronecrosis With Osteomyelitis In Broilers: Bacterial Species Involvement And Influence Of Probiotics And Synbiotics, Amer Abdullah Hasan

Graduate Theses and Dissertations

Since 1945, the market for broiler production has evolved from a collection of smallholder poultry farms into an industry worth billions of dollars. Poultry production has not gone without challenges. Lameness in young broilers is presently a serious issue in the poultry industry for reasons of animal health and welfare, as well as significant lost production and revenue. Bacterial chondronecrosis with osteomyelitis (BCO) is a major form of lameness in broilers. This dissertation contains information about (i) the influence of Staphylococcus agnetis, Staphylococcus saprophyticus, Staphylococcus epidermidis and Enterococcus faecalis on inducing BCO lameness, (ii) evaluation of of probiotics for reducing …

The Effect Of Water Management And Ratoon Rice Cropping On Methane Emissions And Harvest Yield In Arkansas, Marguerita Leavitt

Graduate Theses and Dissertations

Sustainable intensification of rice farming is crucial to meeting human food needs while reducing environmental impacts. Rice produces 8% of all anthropogenic CH4, which is a potent greenhouse gas. CH4 emissions can potentially be reduced by cultivation practices that minimize the number of days the fields are saturated, such as dry-seeding instead of water-seeding and irrigation using the alternate wetting and drying (AWD) technique instead of delayed, continuous flooding (DF). Ratoon cropping, wherein a second crop of rice is grown from the harvested stubble of the first crop, can be used to produce additional yield with minimal labor, but may …

Effects Of An Injectable Zinc Solution At Weaning As An Alternative Castration Method In Beef Cattle, Reagan Nicole Cauble

Graduate Theses and Dissertations

Two experiments were conducted to investigate a 1 mL intratesticular zinc (100 mg Zn) injection administered into each testicle at weaning (Z) and its effects on growth, health, behavior and testosterone. In the first experiment, beef bulls were assigned randomly to treatment at birth: 1) surgically castrated at birth (S; n = 37) or 2) Z (n = 37). Testicular thickness differed by day (P < 0.01) for Z. Testosterone concentrations were greater in Z by d 77 and remained so through d 280 (P = 0.02) compared to S. Zinc injected calves were heavier at the trail’s conclusion (P ≤ 0.04), had greater ADG overall (P < 0.01), heavier hot carcass weight (P = 0.01), and greater lean muscle area (P = 0.01) compared to S; but a lower marbling score (P < 0.01). Yield Grade, dressed carcass yield and fat thickness were similar (P ≥ 0.14). Zinc injected calves had greater haptoglobin (Hp) concentrations (P < 0.01). Zinc injected calves had greater concentrations of white blood cells on d 1 and 2 and greater concentrations and proportions of neutrophils on d 1, 2 and 3 (P < 0.01). Conversely, S had a greater percentage of lymphocytes on d 1, 2 and 3 and a lower ratio of neutrophils to lymphocytes during that same time (P < 0.01). Zinc injected calves spent more time on their side or sternum on d 1 and more time on their side on d 2 while S spend more time standing during that time (P < 0.01). During d 3, 4, 5, and 6, Z stood more while S laid on their sternum (P < 0.01). In trail 2, beef bulls were allocated randomly to treatment one week post weaning: 1) banded (B; n = 42) or 2) Z (n = 39). Body weights were similar (P ≥ 0.39) but ADG improved for Z compared to B (P = 0.05). Testosterone concentrations were greater in Z compared to B (P ≤ 0.02). Testicular width in Z differed by d (P < 0.01). Zinc castrated calves spent more time on their side compared to B one day post castration (P = 0.03) until d 3 and 4 where B spent more time on their side (P ≤ 0.02). Banded calves stood more the first two days (P ≤ 0.01). On days 3, 4, 5, and 6, Z stood more (P ≤ 0.01) while B were on their sternum (P ≤ 0.03). Banded calves had lower Hp concentrations compared to Z (P ≤ 0.01). Total white blood cell concentrations, proportions and concentrations of neutrophils, and proportion of lymphocytes were greater in Z compared to B on d 1, 2, and 3 (P ≤ 0.01). There was no interaction between treatments over time for IL1β, IL6, and TNFα expression (P ≥ 0.83). The findings in both studies indicate that intratesticular Zn injections at weaning can improve growth performance and some carcass attributes but produce a heightened inflammatory and immune response and cause discomfort. Injecting zinc, as formulated and administered in these trails, does not result in complete castration of beef calves at this age and therefore cannot be considered a true castration alternative.

Competing Behaviors Of Thermoregulation And Ambush Foraging In The Timber Rattlesnake (Crotalus Horridus Horridus): A Mechanistic Assessment Of Thermal Conduction, Larry K. Kamees

Graduate Theses and Dissertations

The interaction between the biophysical environment and ectotherm morphology elicits behaviors designed to maintain internal body temperature (Tb) within a range that promotes physiological functions. The short-term requirements of mass (energy requirements) and heat balance are subject to tradeoffs imposed by the organisms current physiological (heat and mass budgets) and environmental (biophysical, demographic, social, and predation) constraints and available resources. In temperate forests, extreme temperatures are common in summer even with intermittent sun exposure due to dense canopy cover. In Spring and Fall, temperatures can range from below freezing to 35 ℃ in 24 hrs. An ambush predator like the …

Rodent Dental Microwear Texture Analysis As A Proxy For Fine-Scale Paleoenvironment Reconstruction, Jenny H. E. Burgman

Graduate Theses and Dissertations

Dental microwear texture analysis (DMTA) of fossil fauna has become a valuable tool for dietary inference and paleoenvironment reconstruction. Most of this work has utilized larger taxa with larger home ranges. These studies may result in broader-scale habitat inferences that could mask the details of complex mosaic habitats. Rodent DMTA offers an opportunity to work at finer spatial scales because most species have smaller home ranges. Rodents are also keystone species within their ecosystems, abundant, ubiquitous, and found in many fossil deposits. These attributes make them excellent proxies for environmental reconstructions. However, the application of DMTA to rodents remains relatively …

Investigating The Mechanics And Chemistry Of Sickle Polish Development, Justin Jared Dubois

Graduate Theses and Dissertations

This series of experiments is designed to understand the development and chemistry of sickle gloss. Sickles are common in the archaeological record and have long been studied for their eponymous “sickle gloss”. There is debate as to how this gloss is formed. Five experimental sickles containing flint and novaculite blades were used to harvest high and low moisture content rye and common fescue and associated field weeds. The differences in the development of sickle gloss were examined. High moisture content plants create thick, smooth fields of polish with undulating, billowing margins at a higher developmental speed. Low moisture content plants …

An Investigation Of Factors Affecting The Rooting Ability Of Hardwood Muscadine Cuttings And Genetic Diversity Of Wild And Cultivated Muscadine Grapes (Vitis Rotundifolia Michx.), Kenneth Buck

Graduate Theses and Dissertations

The muscadine (Vitis rotundifolia syn. Muscadinia rotundifolia) is a grape species native to the southeastern United States. Muscadines are one of three grape species in subgenus Muscadinia with a chromosome number of 2n=40 (V. rotundifolia, V. munsoniana, and V. popenoei), making them genetically distinct from the European wine and table grape (Vitis vinifera) and other species in subgenus Euvitis. Rooting hardwood cuttings from muscadine vines has traditionally been considered an exceptionally difficult task. Many previous studies observed almost no root formation, leading to a general consensus that muscadines should either be propagated by softwood cuttings or vegetative layering. However, the …

Studying Acetylation Of Aconitase Isozymes By Genetic Code Expansion, Jessica Araujo

Graduate Theses and Dissertations

The tricarboxylic acid (TCA) cycle is a very important, centrally located, energy-producing pathway that connects numerous other metabolic and regulatory pathways. Enzymes of this cycle have been more recently implicated in various cancers and neurometabolic disorders, however, the exact mechanism by which this happens becomes quite complex when considering the potential modification of these enzymes and the presence of multiple forms of the enzymes and therefore there is much to be studied in this area.

Aconitase has become a recent enzyme of interest as its substrate, citrate, has been found to play a major role in many vital processes within …

An Engineering And Economic Analysis Of The Implementation Of The Carbo Rock-It, Lydia Huck

Graduate Theses and Dissertations

The patented Carbo Rock-It system was developed to carbonate beverages for the craft brewing industry with the goal of reducing time, cost, and environmental impacts of the carbonation process. This research field tests, models, analyzes and optimizes the engineering and economic performance of a commercial-scale Carbo Rock-It placed in production at an operating brewery (Core Brewing and Distilling Co., Springdale, AR). Field tests indicated that the Carbo Rock-It was able to successfully carbonate twelve 120 BBL batches of Scarlet Letter Seltzer to 3.0 vol/vol while meeting all beverage quality and safety requirements. The Carbo Rock-It was able to reduce carbonation …