Digital Commons Network^™

Phenology And Diversity Of Arthropod Communities In Leaf Litter, Fredericka Hamilton

Graduate Theses and Dissertations

Temperate deciduous forests produce a layer of leaf litter on the forest floor annually. This layer is dynamic, and both the composition and depth change throughout the year. The leaf litter layer is an important habitat to many arthropods since they utilize it for food, shelter from adverse environmental conditions, and protection from predators.

Two commonly encountered and diverse taxa found in the litter layer are the ground beetles (Coleoptera: Carabidae) and the ground spiders (Araneae: Gnaphosidae). Carabidae and Gnaphosidae were collected and identified on a monthly basis from April 2014 to March 2015 from the Ozark Mountains of Arkansas …

Asymmetric Synthesis And Transition Metal-Catalyzed Cross-Coupling Arylations Of Selected Organolithiums, Barry Kyle Sharp

Graduate Theses and Dissertations

My former boss, Dr. Gawley, always loved to say, “The world is chiral” (à la Pasteur). From DNA and proteins to hands and feet, it is obviously true. Also, a wide variety of chemical products exist as single enantiomers. Advances in chemical technology have greatly accelerated asymmetric synthesis in the past quarter century, and namely, organolithiums, have been shown to provide a versatile route to chiral natural products and biologically active molecules. Versatility arises from the array of methods that produce a chiral organolithium. Dynamic thermodynamic resolution (DTR) is considered one of the most practical methods, but among the others …

Effect Of Feeding Regimen And Age On Lipid Metabolism In Broiler Breeder Hens And Progeny, Nirun Boonsinchai

Graduate Theses and Dissertations

Age of hens and feed allocation can affect egg yolk lipid compositions which in turn directly relate to chick quality. A series of experiments were conducted to determine the effects of age and feeding programs on lipid metabolism in breeder hens and progeny. In the first trial, the rate of yolk absorption and fatty acid profiles in the yolk were compared among 28, 35, and 49wk old hens. The results revealed that the rate of yolk absorption was higher, but the absolute amount of fatty acids absorbed was lower in young hens than in the old hens. The second trial …

A Comparison And Exploration Of Arkansas Professional School Counselor Activities Across Poverty, Angela Mccoy Harless

Graduate Theses and Dissertations

This study is an exploration of the actual and preferred practices of Arkansas K-12 school counselors in low, mid, and high-poverty schools using the School Counselor Activity Rating Scale (Scarborough, 2005), follow-up questionnaires, and interviews. The qualitative component of this study brings to light the contextual factors that prevent school counselors from providing direct and indirect services to students outlined in the ASCA National Model. This research study examines the hidden dynamics of the counselor/principal relationship and how this relationship has a pivotal role in the realization of a fully comprehensive developmental school counseling program. This study contributes to the …

Grass Finishing Systems For Lambs, Erin Leigh Smyth

Graduate Theses and Dissertations

There is strong interest in sustainably produced meat. Grass-fed lamb could fulfill this market by reducing off-farm inputs. The objective was to examine the effect of grass-finishing or minimal supplementation on performance of lambs in the southeastern US. Katahdin lambs born in October 2013 and 2014 and February 2014 were weaned in January 2014/2015 and May 2014, respectively. Lambs were blocked by gender (fall; winter included only ram lambs) and randomly assigned to receive no (NON) or grain co-product supplement (SUP; 15% CP) at 0.5% of BW/d. Lambs were rotationally grazed on predominantly grass. Body weight, fecal egg counts (FEC), …

Food Waste At Retail, Erin G. Killeen Davis

Graduate Theses and Dissertations

Food waste at retail represents forgone sales and embodies store management and disposal costs. Fresh produce is the largest contributing sector to food waste at retail and bulky, seasonal products are an added challenge when stores experience a high waste event. In order to improve, retailers need to better understand the costs of food waste, as well as how management strategies can impact these costs.

Using pumpkins as an example of bulky, seasonal products, a twofold research project was conducted to better understand contributors to, and costs of food waste at the retail level. In part one, using data from …

Temperature In The Cotton (Gossypium Hirsutum L.) Canopy And Effects On Cotton Leaf And Boll Growth, Maria Soledad Berlangieri Costa

Graduate Theses and Dissertations

Cotton development and yield are negatively influenced by extremes temperatures, mainly during reproductive stage. Ambient air temperature is used to evaluate temperature stress effect on yield under field conditions; however, there is evidence that actual temperatures in the canopy where bolls develop are different. In terms of cotton responses, there is limited research about the effects of elevated day and night temperatures upon boll carbohydrate content, size, and boll respiration. Field and growth chamber experiments were performed during 2014-2015 using the cotton (Gossypium hirsutum L.) cultivar DP0912B2RF. Field studies for determining temperature gradients through the canopy consisted of two planting …

Shiga Toxin-Producing Escherichia Coli (Stec) Detection Strategies With Formalin-Fixed Stec Cells, Christopher Adam Baker

Graduate Theses and Dissertations

Certain pathogenic Escherichia coli known as Shiga toxin (Stx)-producing Escherichia coli (STEC) are commensals in cattle, and typically cause bloody diarrhea in humans once the Stx toxin is secreted in invaded intestinal epithelial cells. Infections with STEC cells can lead to hemolytic uremic syndrome, which is commonly associated with kidney failure. Several STEC serogroups have been declared adulterants in raw, non-intact ground meat, and future regulations could potentially lead to a higher number of STEC serogroup detection strategies for these pathogenic microorganisms. Microbiological research laboratories may benefit from formalin-fixed STEC cells for periodic (daily, weekly, monthly, among others) instrument validation/calibration …

Addressing Genetic Pollution From Pollen Drift On A Heterogeneous Landscape, Mattia Ciro Mancini

Graduate Theses and Dissertations

Genetically modified (GM) crops are crops in which single or multiple genes have been introduced artificially in order to obtain certain characteristics that are difficult to obtain through conventional breeding. Even though farmers have the right to freely choose what types of crops to grow, pollen mediated gene flow from GM crops to non-GM crops can limit the possibility for crops to coexist on a same landscape, resulting in economic losses that depend on the institutional arrangements and the type of property rights in place. Although it is well known that spatial variability affects the degree of cross-contamination between GM …

Effect Of Germination And Parboiling On Milling, Physicochemical, And Textural Properties Of Medium- And Long-Grain Rough Rice, Ashley Han

Graduate Theses and Dissertations

Germinated brown rice is commonly consumed in Asia for its enhanced nutritional properties such as gamma-aminobutyric acid (GABA) and softer cooked texture. However germination decreases milling yield and alters some physicochemical properties, and most germinated rice studies evaluated medium-grain and aromatic rice cultivars. This study compared the effects of germination duration and parboiling on milling, physicochemical, and textural properties of a medium- (Jupiter) and a long-grain (Wells) rice cultivars. Rough rice was soaked in water at 25°C for 12 hr, and then incubated at 30-34°C for varying germination durations, or combined with parboiling at 120°C for 20 min prior to …

The Reproductive Ecology Of The Timber Rattlesnake, Crotalus Horridus, In Northwestern Arkansas: Interactions Between Environment, Steroid Hormones, And Life History, Craig Michael Lind

Graduate Theses and Dissertations

In this dissertation I examined the relationship between individual energetic status, hormone production, and life history trait expression in field-active Timber Rattlesnakes, Crotalus horridus. In chapter one I reviewed what is known regarding these relationships in snakes and defined major research goals. In chapter two I described the seasonal profile of testosterone (T) and corticosterone (CORT) in relation to the breeding season and to individual energetic status in males. Results showed that the seasonal pattern of T production in C. horridus was different than other pit viper species with similar mating patterns. Testosterone was elevated in the months leading up …

Intestinal Inflammation Model Inducing Gut Leakage By Different Methods In Broiler Chickens Using Fitc-D As A Marker, Eduardo Vicuna

Graduate Theses and Dissertations

Traditionally, antibiotic growth promoters (AGP) have been used in food animals to reduce enteric inflammation and maintain intestinal homeostasis, thus improving performance. Due to increasing restrictions regarding the use of AGP, precise and high throughput enteric inflammation models and markers to search for effective alternatives are urgently needed. Oral administration of fluorescein isothiocyanate dextran (FITC-d) and its passage into blood can be used as a marker for tight junction permeability. FITC-d is a large molecule (3-5 kDa) which does not usually leak through the intact gastrointestinal tract barrier. However, when conditions disrupt the tight junctions between epithelial cells, the FITC-d …

Genetic Mapping Of Yield And Normalized Difference Vegetative Index In Soft Red Winter Wheat (Triticum Aestivum L.), Christopher Keith Addison

Graduate Theses and Dissertations

Wheat is the most widely cultivated cereal crop, being grown on 17% of the global crop land and as such must be adapted to an array of environmental stresses. In order to become a variety, wheat breeding lines must be tested across a range of environments for both high productivity and stability. Quantitative trait loci (QTL) mapping and indices are tools that can aid plant breeders in the selection of superior lines. Soft red winter wheat accounts for 20% of the total wheat production in the United States, being grown in the southeastern U.S. predominantly along the Mississippi River. However, …

The Effects Of Electrostatic Spraying With Organic Acids In The Disintegration Of Biofilms Formed By E.Coli O157:H7 And Salmonella Typhimurium On Spinach And Cantaloupe, Ahmad Almasoud

Graduate Theses and Dissertations

Outbreaks from the consumption of fresh produce are a concern in the United States. The consumptions of fresh produce have increased recently which expose a large segment of society to such outbreaks. Spinach and cantaloupe are minimally heated or processed before consumption which makes them a possible source of foodborne illness. The objective of this research was to investigate the effect of organic acids alone and in combination to reduce attached Salmonella Typhimurium (S.T) and Escherichia coli O157:H7 (E.coli) on spinach and cantaloupe, and to disintegrate biofilm formed by these pathogens by electrostatically spraying with two organic acids. To quantify …

Monitoring Abundance Of Ips Bark Beetles And Determining Related Tree Mortality In Arkansas And Texas, Chandler Stefan Barton

Graduate Theses and Dissertations

The abundance of the southern pine engraver beetles, Ips avulsus (Eichhoff), I. grandicollis (Eichhoff), and I. calligraphus (Germar), was monitored with pheromone-baited traps in 2012 and 2013 in Arkansas and eastern Texas. Additionally, vehicle-based and comprehensive ground-based surveys were used to estimate and confirm the amount of dead and fading trees in each trapping site. Pine engraver beetles have historically been recognized as secondary invaders of healthy trees, but observations of pine mortality in Texas and Arkansas appeared to correspond with high population densities of Ips spp. Forest sites exhibiting subjectively high or low incidence of Ips-associated mortality in Arkansas …

Improving Production Efficiency Of Beef Cow-Calf Operations, Amanda Jo Davis

Graduate Theses and Dissertations

Three studies were conducted to improve and incorporate reproductive management practices into beef cow-calf production. First study evaluated serial use of Estrotect estrous detection patches as a simple, cost-effective reproductive management tool to identify cyclic animals before breeding, distinguish between females conceiving to AI versus natural service, and determine seasonal pregnancy rate after bull removal. Also determined, was effectiveness of altered timing of GnRH treatment (1 d ± CIDR removal) in a modified 14-d CIDR-Select Synch protocol. When evaluated over a 4-wk period, estrous detection patches correctly (P < 0.01) identified 79% of cyclic and 86% of non-cyclic heifers. Patches were 96 and 98% accurate in identifying heifers and cows pregnant by AI, respectively, and were 76 and 87% accurate in identifying pregnant heifers and cows at the end of the breeding season (P < 0.01). Treatment with GnRH at CIDR removal reduced labor costs and animal handling without compromising estrous response (both ~63.0%) and AI pregnancy rates (~76 and 77%; P > 0.1). Second study determined if addition of PGF2alpha treatment on d 7 …

Effects Of Chemical And Enzymatic Modifications On The Starch-Inclusion Complex Formation, Emily Arijaje

Graduate Theses and Dissertations

Starch-inclusion complexes have been proposed as delivery tools for bioactive molecules; however complexation yield is generally low with low solubility, which may limit the bioavailability of the included molecule. It was proposed that chemical (acetylation) and/or enzymatic (isoamylase and beta-amylase) modifications of starches prior to complex formation with fatty acids of different structures, including stearic, oleic and linoleic acid, may help increase complexation yield and solubility of the resulting starch complexes. Potato starch had a significantly higher complexation yield than common corn and high amylose (~70%) corn starches after debranching combined with a beta-amylase treatment. Debranched waxy maize starch and …

Rice Grain Yield And Nitrogen Uptake And Ammonia Volatilization From Urea As Affected By Urea Amendment And Simulated Rainfall, Randy Dempsey

Graduate Theses and Dissertations

The effect of rainfall between urea application and flood establishment on N loss and grain yield of rice (Oryza sativa L.) has not been studied. The first research objective was to compare the effects of simulated rainfall amounts and N-(n-butyl) thiophosphoric triamide (NBPT) urease inhibitor rate on NH3 volatilization and rice growth. Three field experiments were conducted and NH3 volatilization was measured in two experiments for 11 days after urea application (DAU) in semi-open chambers. Urea or NBPT-treated urea (NBPT-Urea) was subjected to six simulated rainfall amounts (0-25 mm) applied 5 to 15 h after urea application and flooded 7 …

Efficacy Of Beta-Resorcylic Acid To Reduce Campylobacter Jejuni In Pre-Harvest And Post-Harvest Poultry, Basanta Raj Wagle

Graduate Theses and Dissertations

Campylobacteriosis is one of the leading foodborne illnesses in United States, and is associated with the consumption of poultry and poultry products. Reducing Campylobacter in these species will reduce the burden of this disease. Unfortunately, most strategies employed to reduce Campylobacter in poultry have either not been successful or produced inconsistent results. One potential control strategy is the use of β-resorcylic acid (BR), a phytophenolic compound classified by the US FDA as "Everything Added to Food in the United States" (EAF 3045) and is therefore deemed safe for consumption. This compounds has antibacterial activity against Salmonella, however, its efficacy to …

Dlipin-A Link Between Lipid Metabolism, Glucose Homeostasis And Growth In Drosophila Melanogaster, Sandra Schmitt

Graduate Theses and Dissertations

Lipins are a family of highly conserved proteins found from yeasts to humans. Lipins have dual functions, serving as phosphatidate phosphatase enzymes (PAP) in the synthesis of neutral fats (triacylglycerols, TAG) and as transcriptional co-regulators that affect the expression of genes involved in lipid and fatty acid metabolism. Thus, they play central roles in metabolic control. Disruption of Lipin function has been implicated in lipodystrophy, obesity and insulin resistance. Using dLipin, the Drosophila homolog of Lipin, as a model, I aimed to elucidate the relationship between the two biochemical functions of Lipin and metabolic homeostasis. I discovered there is a …

The Effect Of Physical Activity Levels On Hydration Markers In Non-Athletic Free-Living Individuals, Mikell Lucas Hammer

Graduate Theses and Dissertations

Higher levels of physical activity requires increased fluid intake due to increased water losses via sweating. PURPOSE: To determine the effect of physical activity on hydration status and water intake. METHODS: This study involved 8 visits to the Human Performance Laboratory over 22 days. Body weight and urine measurements were taken every visit. Physical activity was assessed by the International Physical Activity Questionnaire (IPAQ), water intake by the Water Frequency Questionnaire (WFQ), and hydration status by urine osmolality (UOsm), urine specific gravity (USG), and urine color (UC). From the IPAQ subjects were classified as low, moderate and high physical activity …

Divergent Selection For Four-Day Relative Breast Yield And The Effect Of Thermal Manipulations On Growth Characteristics On Lines Selected For Different Processing Dates., James Grant Mason

Graduate Theses and Dissertations

Genetic selections currently utilized in the poultry industry have been highly successful in promoting broiler growth rate and yield. However, these selections may have come at the expense of broiler physiology, as evidenced by an increase in physiological disorders. To address this experimentation was undergone to develop a novel method of selection to promote growth with minimal physiological impact and to assess how a new embryonic technique affects growth in broiler lines exhibiting different growth rates.

In the first experiment, a random bred control (RAN) broiler line was divergently selected for four-day relative breast yield (BY4) resulting in the high …

Hypohydration And Mood State In Free-Living Males And Females, Thomas Edward Vidal

Graduate Theses and Dissertations

Previous research has shown that acute dehydration can result in changes in mood. These changes have been reported in less than a 1% loss in total body water. However, the effect of hypohydration (i.e., reflected through high urine concentration) on mood in free-living conditions has not been studied. PURPOSE: The present study was designed to determine if hydration status is associated with mood within the general population under free-living conditions. METHODS: A group of 103 apparently healthy subjects (49 male, 54 female, 41±14 y, 1.7±0.1 m, 76.1±16.9 kg) completed three visits separated by a week. Mood was assessed by the …

Application Of Essential Oil Compounds And Bacteriophage To Control Staphylococcus Aureus, Anisha Ghosh

Graduate Theses and Dissertations

Staphylococcus aureus is one of the most important pathogens, causing various diseases in humans and animals. In addition, S. aureus is a common foodborne pathogen. As methicillin- resistant S. aureus (MRSA) becomes increasingly prevalent, controlling this pathogen in animals and humans with standard antibiotic treatment has become challenging. Combinations of different antimicrobial agents represent one of the most promising approaches for combating multidrug - resistant bacteria both for treatment of clinical disease as well as in food. Two such antimicrobials with potential application in the food industry include essential oils (EO) and host-specific bacteriophage (phage). The objectives of this study …

The Paleoepidemiology Of Malaria In The Ancient Near East, Nicole Elizabeth Smith

Graduate Theses and Dissertations

The end of the Late Bronze Age in the Near East (1300 - 1200 BCE) saw the widespread collapse of several large cultural centers, the reasons for which are a subject of continued debate. Evidence from events leading up to this cultural collapse suggest epidemic disease may have factored into the eventual downfall of these early civilizations. Recent DNA analysis from Egyptian mummies who lived during the period leading up to the Late Bronze Age collapse identified malaria in several elite individuals, suggesting the widespread prevalence of this infectious disease in Egypt. However, the exact prevalence, antiquity, and dynamics of …

Nutrient Management For Growing Dandelion (Taraxacum Officinale L.) In Nutrient Film And Deep Flow Hydroponics, Reetinder Gill

Graduate Theses and Dissertations

This research study was conducted to determine an optimal nutrient strategy for dandelion production in nutrient film technique (NFT) and deep flow technique (DFT) systems of hydroponics. It was achieved by growing dandelion at varying levels of nutrient solution concentration and pH in both NFT and DFT systems. Additionally, an optimal nutrient solution concentration and timing of application for dandelion seedling production was also determined.

An Examination Of Psychoeducation And Its Potential Modifying Influence On Alcohol Use Patterns Among Adults Reporting Co-Occurring Posttraumatic Stress Symptoms And Hazardous Alcohol Consumption, Sarah Jo Bujarski

Graduate Theses and Dissertations

Research has suggested that consumption of alcohol in the presence of elevated posttraumatic stress symptom (PTSS) may serve an avoidant function to cope with negative emotions. These coping-related motives for use are theorized to both maintain PTSS and relate to poorer prognoses in treatment for alcohol use disorders (AUDs). Treatments utilizing coping skills training, which typically also involves educating clients about the negative consequences of drinking alcohol to cope, suggest the utility of targeting coping behaviors to reduce alcohol use. These studies, however, have not attempted to isolate the effects of psychoeducation on alcohol-related factors. The current study investigated the …

Understanding The Evolution Of Aggregative Multicellularity: A Molecular Phylogenetic Study Of The Cellular Slime Mold Genera Sorodiplophrys And Pocheina, Alexander Tice

Graduate Theses and Dissertations

Cellular slime molds are amoeboid protists that have a unicellular trophic phase and multicellular dispersal stage formed through the aggregation of individuals in their life cycles. These organisms were once thought to form a monophyletic group in the Mycetozoa. After careful morphological, ultrastructural, and molecular studies, cellular slime molds are now thought to be distantly related organisms that have all converged on the cellular slime mold habit. The following thesis consists of two molecular phylogenetic studies on two named genera of cellular slime mold for which little or no molecular data were publically available. In the first study, gene sequence …

Physiological And Nutritional Characterization Of High Yield Soybean, Ryan John Van Roekel

Graduate Theses and Dissertations

Soybean [Glycine max (L.) Merr.] grain yields greater than three times the national average have been reported in yield contests. Characterization of soybean in a maximum yield environment is necessary to provide empirical data to support those yield claims and to provide an understanding of the physiological processes at that yield level. From 2011 to 2013, research characterized biomass and N accumulation rates, radiation use efficiency (RUE), leaf N dynamics, the rate of harvest index increase (dry matter allocation coefficient, DMAC), seedfill period (SFP), and grain yield components from Mr. Kip Cullers' contest fields and in small plots at the …

Effects Of Mild Hypohydration And Hyperthermia On Cognition And Mood In Obese And Non-Obese Females, Jenna Marie Burchfield

Graduate Theses and Dissertations

INTRODUCTION: Information regarding effects of hypohydration (HY) and hyperthermia (HT) on cognition, mood and development of symptoms is conflicting since the two conditions often confound each other. Further, although obese individuals may have physiological impairments during heat stress, whether psychological impairments occur with HY and HT is unknown. PURPOSE: To assess the independent and combined effects of mild HY and HT on cognition, mood, and the development of symptoms in obese and non-obese females. METHODS: Twenty-two healthy females (11 non-obese, 22±2y, 61±6kg, 25±4% body fat; 11 obese, 22±2y, 80±18kg, 44±5% body fat) volunteered in two randomized, repeated-measures trials, involving passive …