Digital Commons Network^™

Responses Of Semi-Aquatic Snakes To Drought, Philip Nicholas Vogrinc

Graduate Theses and Dissertations

Aquatic ecosystems and their associated wildlife are threatened by alteration in the frequency and intensity of precipitation events predicted to affect many regions as a consequence of global climate change. Semi-aquatic snakes serve important roles as predators and prey within aquatic ecosystems, yet little is known about the effects of drought on these species due to their secretive behavior. Long-term studies at an isolated wetland in South Carolina found that drought caused populations of banded watersnakes (Nerodia fasciata) and Florida green watersnakes (Nerodia floridana) to crash. Alternatively, black swamp snakes (Seminatrix pygaea) fared well, exhibiting a resistance strategy by aestivating …

A Gnawing Problem: Does Rodent Incisor Microwear Record Diet Or Habitat?, Salvatore Samuel Caporale

Graduate Theses and Dissertations

Dental microwear has been shown to reflect food preferences and habitat in extant vertebrates, and its analysis has been applied to fossil assemblages to infer paleodiet and paleoenvironment. Such reconstructions are, of course, only as good as the extant baseline used to infer relationships between wear pattern and diet/habitat. This study tests, through dental microwear texture analysis, the potential of modern rodent lower incisors to reveal those relationships, and evaluates the extent to which effects of diet and habitat can be parsed from the signal. Microwear texture profiles were created for individual lower rodent incisors (n=430) using confocal profilometry and …

Development Of Infrared Heating Technology For Corn Drying And Decontamination To Maintain Quality And Prevent Mycotoxins, Shantae Wilson

Graduate Theses and Dissertations

Infrared (IR) heating of corn followed by tempering treatments has potential to rapidly dry and simultaneously decontaminate corn without adverse effect on the overall quality. However, it is vital to determine the optimal processing parameters that maximize throughput and minimize drying energy without affecting overall corn quality. This study investigated the effects of IR heating and tempering treatments on moisture removal, mold load reduction, corn color change, and drying energy requirements. In addition, the study evaluated the feasibility of scaling up IR drying process using a newly built, pilot scale IR dryer. Freshly harvested corn with initial moisture content (IMC) …

Investigation Of Optical Properties Of Zinc Oxide Photodetector, Tyler Chism

Graduate Theses and Dissertations

UV photodetection devices have many important applications for uses in biological detection, gas sensing, weaponry detection, fire detection, chemical analysis, and many others. Today’s photodetectors often utilize semiconductors such as GaAs to achieve high responsivity and sensitivity. Zinc oxide, unlike many other semiconductors, is cheap, abundant, non-toxic, and easy to grow different morphologies at the micro and nano scale. With the proliferation of these devices also comes the impending need to further study optics and photonics in relation to phononics and plasmonics, and the general principles underlying the interaction of photons with solid state matter and, specifically, semiconductors. For this …

Validation Of A Confocal Light Sheet Microscope Using Push Broom Translation For Biomedical Applications, Joshua Hutcheson

Graduate Theses and Dissertations

There exists a need for research of optical methods capable of image cytometry suitable for point-of-care technology. To propose am optical approach with no moving parts for simplification of mechanical components for the further development of the technology to the poin-of-care, a linear sensor with push broom translation method. Push broom translation is a method of moving objects by the sensor for an extended field of view. A polydimethylsiloxane (PDMS) microfluidic chamber with a syringe pump was used to deliver objects by the sensor. The volumetric rate of the pump was correlated to the integration time of the sensor to …

Effect Of Potassium Deficiency On Uptake And Partitioning In The Cotton (Gossypium Hirsutum L.) Plant And Detection By A Crop Reflectance Sensor, Taylor Dayne Coomer

Graduate Theses and Dissertations

For cotton (Gossypium hirsutum L.) to grow and develop normally, plants need to uptake the necessary amount of nutrients and use those nutrients in a beneficial fashion. It is recognized that cotton needs a certain tissue concentration of ions to achieve and maintain growth rates (Siddiqi et al., 1987). One of the most essential and abundant nutrients in cotton is potassium (K), second only by mass to nitrogen (N) (Marschner, 1995; Oosterhuis et al., 2013). Potassium exists in the soil in four separate pools and moves through soil to roots mainly through diffusion (Rengel & Damon, 2008; Samal et al., …

Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson

Graduate Theses and Dissertations

A widespread stressor, anthropogenic nitrogen (N) and phosphorus (P) pollution can increase resource nutrient content and alter animal community composition in freshwater ecosystems. In this dissertation, I used ecological stoichiometry theory to examine effects of diet nutrient content and leaf litter type on growth, regulation, and wastes of aquatic invertebrate detritivores. I tested effects of leaf litter diet carbon:phosphorus (C:P) on growth and stoichiometric regulation of the detritivorous caddisfly Pycnopsyche lepida and used results to determine a threshold elemental ratio of oak litter C:P=1620 that confers peak growth of this species. This empirical, growth-based approach provided a more accurate estimate …

Autophagy Regulation After Diet And Exercise In Non-Alcoholic Fatty Liver Disease, Megan Elizabeth Rosa

Graduate Theses and Dissertations

Along with the rise in obesity, rates of non-alcoholic fatty liver disease (NAFLD) have also increased. NAFLD may begin with fat accumulation in the liver, but can progress to non-alcoholic steatohepatitis (NASH), fibrosis, and eventual cirrhosis. With no pharmacological treatment for NASH, lifestyle interventions appear vital to maintaining liver health. Previous work has shown aberrant mitochondrial content/quality and autophagy in models of NAFLD. Exercise is known to improve mitochondrial health and possibly autophagy, thus autophagy may be a key regulatory factor for treatment of obesity induced-NAFLD. PURPOSE: The purpose of the study was to examine how weight loss from diet …

Comparative Efficacy Of Foaming And Non-Foaming Handsoap In Reduction Of Microorganisms In Handwashing, Danielle Marie Conover

Graduate Theses and Dissertations

Handwashing (HW) is a long established method to prevent disease transmission. Ensuring effectiveness of current HW methods is essential for optimal HW and enhanced disease prevention. The objectives of this research were to 1) conduct a survey of soap type and volume in food service establishments in Washington County, Arkansas; 2) investigate how soap type impacts HW behavior; and 3) determine the difference in microbial reduction between foaming (F) and liquid (L) handsoap. For Objective 1, food service establishments in Washington County, AR were selected based on exclusion criteria and random number generations, and handsoap samples were collected to determine …

Walking In American History: How Long Distance Foot Travel Shaped Views Of Nature And Society In Early Modern America, Brian Christopher Hurley

Graduate Theses and Dissertations

The industrialization of transportation, first with railroads, and then with automobiles, took Americans away from foot transport, changing how Americans interacted with one another and viewed their surroundings. The dissertation traces the walking trips of five central figures in this era of mechanized transport, the personal impact of their experiences while walking through a land they were accustomed to skimming across, and the ways in which these personal revelations led to changes in the national consciousness. Walking upright was central to the development of homo sapiens as a species, and shaped the way they interacted with their environment. Certain aspects …

Dissemination And Persistence Of Plasmid Located, Integron Associated Antibiotic Resistant Genes In Wastewater Treatment Plant Effluent And Stream Water Bacteria, _ Suhartono

Graduate Theses and Dissertations

Transmissible plasmid-mediated integrons play important role in the persistence and dissemination of antibiotic resistance throughout the environment. Plasmids from 139 multi-antibiotic resistant Escherichia coli recovered from wastewater treatment plant effluent and upstream and downstream receiving stream water in Northwest Arkansas were extracted and profiled. Genes of class 1 and class 2 integrase (intI), mobilization (mob), sulfamethoxazole resistance (sul), and trimethoprim resistance (dfr) were detected using PCR and confirmed through DNA sequencing. Plasmids from almost half of the isolates (47%) were transmissible with mobF12 gene as the most frequently detected mobilization gene. Plasmid-borne class 1 with and without class 2 integrons …

Gene Expression And Physiological Analysis To Study Differences Between Oryza Sativa Cultivars Susceptible And Resistant To Chalky Grain Formation Subjected To High Nighttime Temperatures., Nicholas Lawson

Graduate Theses and Dissertations

Starch composition and grain quality of rice is greatly influenced by genotype and environmental factors. The detrimental effects of high nighttime temperatures on rice yield and quality has recently become apparent, with some of the warmest average nighttime temperatures being recorded in the past few years. One of the most notable effects of this stress, an increase in grain chalk formation, correlates with a decrease in quality. This effect varies greatly between cultivars as some show less temperature-sensitive quality reduction than others. The goal of this research is to elucidate fundamental changes that occur in developing plants and grains as …

Integrative Taxonomy Of North American Torrent Mites (Parasitengona: Torrenticolidae: Torrenticola), Jon Ray Fisher

Graduate Theses and Dissertations

Mites are notorious for being under-studied and incomplete knowledge of distribution, life-history, and morphology are commonplace. They typically gain attention through the relatively few pest species that plague our crops, pets, or bodies. Despite representing a successful radiation with an estimated 3–5 million species, relatively few mite lineages attract research attention from non-acarologists. However, the largest radiation of all mites—Parasitengona—has potential to bridge the gap between specialists and non-specialists. Parasitengona are the butterflies of the mite world. Obvious are the bright red mites searching for pollen on concrete, or the large, furry velvet mites coming out to mate after spring …

Identification Of Biomarkers For The Overall Survival Of Ovarian Cancer Patients, Kristi Mai

Graduate Theses and Dissertations

Rapid advance in sequencing technology has led to genome-wide analysis of genetic and epigenetic features simultaneously, making it possible to understand the biological mechanisms underlying cancer initiation and progression. However, how to identify important prognostic features poses a great challenge for both statistical modeling and computing. In this thesis, a network-based approach is applied to the Cancer Genome Atlas (TCGA) ovarian cancer data to identify important genes related to the overall survival of ovarian cancer patients. In the first step, a stepwise correlation-based selector is used to reduce the dimensionality of TCGA data, by filtering out a large number of …

Spinach (Spinacia Oleracea L.) Seed Germination And Whole Plant Growth Response To Heat Stress And Association Mapping Of Bolting, Tallness And Erectness For Use In Spinach Breeding, Jessica Chitwood

Graduate Theses and Dissertations

The effect of temperature on spinach seed germination was evaluated using a total of nine spinach genotypes and seven temperatures: 10, 15, 20, 25, 30, 32, and 35 oC in growth chambers. Genetic variation was observed. ‘Donkey’, ‘Marabu’, and ‘Raccoon’ showed higher seed germination percentage with over 70% at 30 and 32 oC, indicating the three spinach genotypes had heat-tolerance for germination. However, all spinach genotypes except ‘Ozarka II’ had lower germination percentages of less than 30% while ‘Ozarka II’ had 63% at 35 oC, indicating ‘Ozarka II’ may be a source of heat-tolerance for seed germination.

Seed germination may …

Genotoxicity Of Graphene In Escherichia Coli, Ananya Sharma

Graduate Theses and Dissertations

Rapid advances in nanotechnology necessitate assessment of the safety of nanomaterials in the resulting products and applications. One key nanomaterial attracting much interest in many areas of science and technology is graphene. Graphene is a one atom thick carbon allotrope arranged in a two-dimensional honeycomb lattice. In addition to being extremely thin, graphene has several extraordinary physical properties such as its exceptional mechanical strength, thermal stability, and high electrical conductivity. Graphene itself is relatively chemically inert and therefore pristine graphene must undergo a process called functionalization, which is combination of chemical and physical treatments that change the properties of graphene, …

The Effect Of The Expanded Food And Nutrition Education Program On Participants’ Diet Quality: Does Supermarket Access Matter?, Rachel Ann Spencer

Graduate Theses and Dissertations

This project assesses the effectiveness of the Expanded Food and Nutrition Education Program (EFNEP) within the context of supermarket access. EFNEP is a national community nutrition education program that strives to give participants the tools to live healthier lives. Analysis was performed on participants from 16 Arkansas counties that completed EFNEP during 2013 or 2014. The program outcome is measured in terms of the change in Healthy Eating Index (HEI) as calculated from 24-hour diet recalls at program entry and exit. Supermarket locations were obtained from the USDA Food Nutrition Service’s SNAP Retail Locator and represent the food environment near …

Oxidative Stress Response In Archaea: Elucidation Of Oxidant Sensing And Tolerance Mechanisms In Methanosarcina Acetivorans, Matthew Edward Jennings

Graduate Theses and Dissertations

Methanogens are archaea possessing a conserved metabolic pathway which produces methane. Many of the enzymes in the methanogenesis pathway are Fe-S proteins, meaning methanogens are sensitive to conditions which disrupt Fe-S clusters. Molecular oxygen is capable of disrupting Fe-S clusters through oxidation of the iron atoms. Furthermore, reduced iron can facilitate the production of reactive oxygen species (ROS), meaning methanogens must possess antioxidant mechanisms. Detection and eradication of ROS is important for all cells, due to the potentially fatal consequences of unchecked oxidation. This dissertation presents two separate projects investigating mechanisms the model methanogen Methanosarcina acetivorans possess for dealing with …

The Influences Of Texture And Mastication Pattern On Flavor Perception Across The Lifespan, Curtis Robert Luckett

Graduate Theses and Dissertations

Texture is an often-overlooked food attribute and is known to influence other food characteristics. More specifically, texture has been repeatedly to influence how we perceive flavor. Several studies have linked this change in flavor perception to the altered mastication patterns that accompany texture changes. This dissertation is composed of four studies that were designed to address how American food consumers view texture and other food attributes as well as characterize how texture and mastication can influence temporal flavor dynamics. The first study was a survey that outlined consumer attitudes towards a variety of different foods. This study solidified that texture …

The Role Of Child Anxiety In Parent Sick Role Reinforcement, Sarah Ann Bilsky

Graduate Theses and Dissertations

A large body of evidence suggests that parents can facilitate offspring anxiety in response to bodily arousal. These learning experiences are referred to as “sick role reinforcement,” and are particularly important during adolescence, given the profound bodily changes (e.g., puberty) that characterize this period. Sick role reinforcement is likely important in the context of panic disorder (PD). Panic theorists suggest that parents may enhance panic vulnerability by increasing the threat value of bodily sensations. Although a sizeable body of work has examined the role of parent behavior in these processes, few have examined offspring factors in this process. Additionally, little …

Toddlers And Technology: An Examination Of How The Digital Surround May Be Related To Prototypic Vocabulary Development And Social Interactions During Play, Hannah Biarnesen Hutcheson

Graduate Theses and Dissertations

This study sought to examine how the digital technology that surrounds young children may be related to prototypic vocabulary development and Social interactions during play. Twenty-six families in the Northwest Arkansas region with children between 15-36 months of age participated in the study. Thirteen children attended a campus preschool, six children attended a grant-funded local preschool, and seven children, all from the Northwest Arkansas area, were part of an earlier home-based study. The materials for the study included a developmental-technology use questionnaire and the MacArthur-Bates Communicative Development Inventories. Archival videotaped play sessions with the seven home-based children utilized a “Little …

Influence Of Fatty Acids And Their Derivatives On Aphid Resistance In Arabidopsis And Tomato, Jiamei Li

Graduate Theses and Dissertations

Fatty acid desaturases (FADs) are enzymes that act in the chloroplast or the endoplasmic reticulum (ER) to incorporate double bonds into the acyl chains of fatty acids, and recent evidence indicates that at least one of these enzymes, FAD7, also influences plant resistance to aphids. FAD7 is an enzyme in the chloroplast that is found throughout the plant kingdom and that desaturates 16- and 18-carbon fatty acids (FAs) with two double bonds (dienoic acids) to generate FAs with three double bonds (trienoic acids). In tomato (Solanum lycopersicum) and the model plant Arabidopsis thaliana, mutants with impaired FAD7 function are more …

Effect Of Passive Heating On Males And Females With Elevated Arterial Stiffness, Forrest Blake Robinson

Graduate Theses and Dissertations

Context: Cardiovascular disease (CVD) is one of the leading causes of mortality in the United States, accounting for about 1 in every 4 deaths annually. Studies have shown that passive heating does have some degree of effect on arterial stiffness, but not much is known about populations with higher stiffness. Objective: To examine the independent effect of core temperature increase during passive heating on arterial stiffness. Methods: Participants visited the lab three times; one familiarization and two experimental trials. The experimental trials consisted of subjects being passively heated in an environment of 40°C / 40% relative humidity (HEAT) or normal …

Effects Of Delayed Drying And Storage Conditions On Milling, Color, And Viscosity Properties Of Rice, Kathryn Nicole Haydon

Graduate Theses and Dissertations

Head rice yields (HRYs), kernel discoloration, and functional properties are three hallmarks of rice quality, and can be impacted after harvest by storage conditions. This study evaluated impacts on rice quality due to controlled storage at moisture contents (MCs), temperatures, and storage durations that may be incurred during Mid-South rice farming practices. Three hybrid, long-grain cultivars, harvested in Arkansas in 2014 and 2015, were stored in rough rice form at 4 MCs (12.5%, 16%, 19%, and 21%), and 5 temperatures (10°C, 15°C, 20°C, 27°C, and 40°C), for 16 weeks, with samples taken every 2 weeks. After drying and milling, HRYs, …

Use Of A Blunt Version Of Meullenet-Owens Razor Shear To Analyze Meat Qualities Of Broilers With Woody Breast Myopathy And Reared To Various Ages, Famous Lue Yang

Graduate Theses and Dissertations

Broiler breast meat tenderness is an important meat quality attribute. There has been an increase in incidences of woody breast along with white striping as meat quality defects. These defects have been found to negatively impact meat qualities of broiler breast fillets. Woody breast can be classified by the degree of hardness into normal (NORM) and severe (SEV). The Meullenet-Owens Razor Shear (MORS) method was developed to assess broiler meat tenderness and a blunt version (BMORS) has been reported to be more sensitive at higher degrees of toughness. The present study was intended to determine the effect of age, debone …

[Re]Visiting The Rime: A Case Study Of Adaptation As Process And Product With The Rime Of The Ancient Mariner, Sally Ferguson

Graduate Theses and Dissertations

This thesis combines adaptation theory with ecology to examine Samuel Taylor Coleridge's Rime of the Ancient Mariner (1798) and its adaptations; it argues further combinations of adaptation with evolutionary theory and ecological ideas could allow for a better interpretation of many texts. The adaptation Rime of the Modern Mariner (2011) by Nick Hayes and the appropriation Perelandra (1943) by C.S. Lewis will also be present in individual chapters to examine the texts' interactions with each other as they evolve and how each work represents the combined theory.

Cloning, Fed-Batch Expression And Purification Of A Novel Anti-Candida Peptide And Development Of A Cleavage Resistant Variant Of Green Fluorescence Protein, Rudra Palash Mukherjee

Graduate Theses and Dissertations

This work illustrates that the intelligent design of a bioprocess for the production of peptides of various length is possible by having a prior knowledge of desired product, cell line, fermentation conditions, and choices for downstream recovery. Cloning, expression, and recovery of a novel 12-mer anti-Candida peptide served as an illustrative case for a proposed Escherichia coli platform. The antifungal peptide, expressed as a fusion to GFPUV during high call density fed-batch, was recovered from cell lysate, concentrated using ion exchange chromatography, and finally cleaved with cyanogen bromide. The platform was capable of producing active peptide capable of arresting the …

Meat Quality And Sensory Analysis Of Broiler Breast Fillets With Woody Breast Muscle Myopathy, Jessica Solo

Graduate Theses and Dissertations

Recently, the poultry industry has encountered an emerging muscle myopathy known as woody breast (WB), which is characterized by hardness throughout the Pectoralis major muscle. Two experiments were performed to assess sensory characteristics and acceptability of WB meat and to determine the effect of broiler age on meat quality factors in varying severities of WB. Fillets were categorized as normal (NORM), moderate (MOD), or severe (SEV) WB. In Experiment 1 (Exp. 1), descriptive (n=9 trained panelists) and consumer (n=74 panelists) sensory analysis was conducted with NORM and SEV fillets at hot and cold serving temperatures (HOTNORM, COLDNORM, HOTSEV, COLDSEV). In …

The Role Of Hydrologic Regimes In Driving Morphologic Divergence And The Trait Compositions Of Fish Assemblages, Lindsey A. Bruckerhoff

Graduate Theses and Dissertations

The hydrologic regime is an important determinant of the ecological integrity of a stream. Hydrologic regimes are defined by the magnitude, timing, frequency, rate of change, and duration of high and low flow events and capture long term patterns of variability and predictability of water movement in a stream. Flow regimes influence many aspects of the biophysical environment in lotic systems; therefore organisms have adapted to natural flow patterns. We investigated how fish have adapted to flow regimes at both a population and community level. In the first study presented in this thesis, we hypothesized fish exhibit phenotypic divergence to …

Designing Sewn Circuits And Stem Self-Efficacy In Middle School Girls, Kara Kaiser

Graduate Theses and Dissertations

The purpose of this study is to determine if the experience of designing and sewing LilyPad Arduino circuits in crafts projects can increase middle school girls’ STEM self-efficacy. Boys STEM self-efficacy will also be assessed to determine if LilyPad Arduino circuits can also increase boys’ STEM self-efficacy. Researchers have been wondering why there is a male dominance in STEM (science, technology, engineering and mathematics) fields and why some women do not have a particular interest in these subjects. There are several reasons this could happen; stereotypes conveyed to them by parents and/or teachers, they genuinely are not interested in STEM …