Digital Commons Network^™

Lactic Acid Production Using Sweet Potato Processing Waste, Irene Pagana

Graduate Theses and Dissertations

Organic waste generated from industrial sweet potato canning is estimated to be 30% of incoming raw material. This waste contains carbohydrates (sugars and starch) that could be used as substrates for the production of useful compounds via fermentation (e.g. lactic acid), resulting in the production of value-added products. The goal of this research project is to produce a substrate from the sweet potato processing waste material that supports the growth of lactic acid bacteria, which results in the production of lactic acid. The sweet potato waste product was characterized, and found to contain 16.5% solids. The solids components were 18.5% …

A Daily Temperature Record For Central Texas, 1896-2011, Matthew Kain Taylor

Graduate Theses and Dissertations

A continuous record of 882,693 daily maximum, minimum, and mean temperature measurements for seven weather stations in central Texas dating from August 1, 1896, to August 31, 2011, were screened and corrected for missing values and inhomogeneities. The resulting data were averaged to create a 115-year unbroken regional record of daily temperature for central Texas. This record indicates warming in daily, seasonal, and annual temperatures. Winter warm temperature extremes have increased over the period of record while warm temperature extremes during the summer months have remained largely unchanged. Summer heat wave days and the length of heat waves have increased …

Soybean Maturity Group Tradeoffs: Irrigation, Weed Control, And Nitrogen Fixation, Ryan Wegerer

Graduate Theses and Dissertations

This thesis is divided into four chapters. Chapter I introduces the rationale behind the study and gives a brief overview of the overall study covering weed control, irrigation needs and nitrogen fixation amounts across soybean maturity group. Chapter II will go into further detail outlining the first applied experiment dealing with weed control and irrigation issues. Alternative weed control methods are analyzed in conjunction with irrigation risk analysis across soybean maturity group in response to agricultural issues of glyphosate resistance and declining ground water supply in the Arkansas delta region. Chapter III will jointly examine irrigation application amounts and nitrogen …

Impact Of Hybrid Rice On Food Security: A Spatial Equilibrium Analysis Of Global Adoption And Diffusion Of Hybrid Rice Varieties, Till Ludwig

Graduate Theses and Dissertations

Rice is the staple crop for most consumers in Asia. More than half of the global population depends on rice. However, scarce resources for agricultural production and unfavorable conditions will make it hard to meet future demand in rice and threaten future food security. Hybrid rice technology is a method to increase the productivity of resources needed for rice production. Current developments show not only yield improvements in comparison to existing conventional and hybrid varieties, but also fuel hopes for new abiotic and biotic stress tolerance. The objective of this study is to determine what impact hybrid rice varieties can …

Investigations Of Protein-Lipid Interactions In Model Membranes: Influence Of Aromatic Anchoring Residues And Buried Polar Residues, Nick Gleason

Graduate Theses and Dissertations

To investigate in detail the interactions between transmembrane proteins and the lipid bilayers in which they are constituted, designed model peptides with selective isotopic labels were synthesized and analyzed by means of solid-state deuterium NMR spectroscopy. Starting from the well-characterized model peptide GWALP23, acetyl-GGALW(LA)6LWLAGA-amide, several Trp to Tyr mutations were compared to evaluate their respective interfacial anchoring abilities. It was found that Tyr, substituted on either or both termini, can effectively anchor the transmembrane alpha-helix, which then adopts a similar transmembrane topology in a range of bilayer thicknesses. Nevertheless, a consistent ~10° shift in tilt direction (helix rotation) is observed …

Peptoid Based Slide Coatings For Disease Detection Via Elisa Microarray Analysis, Melissa Lea Hebert

Graduate Theses and Dissertations

Poly-N-substituted glycines (peptoids) are a very versatile family of synthetic molecules that can be customized for any number of applications. In this study, we chose to use peptoids as a foundation for sandwich ELISA microarray analysis with a long term goal of creating an early detection device for complex diseases such as cancer. The peptoids were designed to self-assemble into microspheres to be used in coatings on the surface of the microarray substrates to increase the surface area available for antibody attachment. This increased antibody density would lead to an increase in the microarray analysis sensitivity and dynamic range. Studies …

Comparative Response Of Different Broiler Genotypes To Dietary Nutrient Levels, Franco Javier Mussini

Graduate Theses and Dissertations

ABSTRACT

Three studies were conducted to evaluate how the broiler has changed over the years due to intense genetic selection. Four different broiler genotypes, one unselected since the 1950's (HER) representing the old meat-type bird and three current strains (Ross 308, Ross 708, and a test product (TY)) were studied. Differences in growth, morphometry, and response in performance and processing yield to different nutrient levels were studied.

Experiment 1 evaluated growth and morphometric analysis. Birds of each strain were killed weekly from day 7 to day 56, necropsied and cut up parts and organs weighed. Measurement of small intestine segments …

Optimization Of A Dynamic Hot Water Pretreatment Of Switchgrass Using Catalysis By Carbonation To Maximize Carbochemical Yields, Rohit Tanaji Dhamdere

Graduate Theses and Dissertations

A bio-refinery is a facility that converts renewable bio-resources into value-added chemicals and products. In this context of a bio-refinery, the production of the carbochemicals such as HMF, furfural and organic acids illustrate that multiple products can be produced from a renewable source such as lignocellulosic biomass (switchgrass). Traditionally, carbochemicals such as furfural and HMF are produced using inorganic acids such as H2SO4, HCL, and H3PO4. The use of such acids requires the application of high cost materials of construction such as Hastelloy-C, titanium etc.

The objective of this study is to develop a semi-continuous process for the conversion of …

The Use Of Cortisol And Hba1c As Biomarkers Of Stress In University Administrators, Jacilyn Marie Olson

Graduate Theses and Dissertations

PURPOSE: The purpose of this study was to explore the impact of perceived stress and cardiorespiratory fitness on cortisol and HbA1c, biomarkers of stress, in a group of select university administrators. The impact of gender on these relationships was of special concern. METHODS: University administrators with job titles of Chancellor, Provost, Vice Chancellors and Vice Provosts of the university, and Deans and Associate Deans at the college level were recruited. Twenty-five administrators (15 males and 10 females) agreed to participate and completed a battery of assessments that included completion of the University Administrative Concerns Questionnaire, a finger-stick blood test for …

The Inclusion Of The Nature Of Science And Its Elements In Recent Popular Science Writing For Adults And Young Adults, Feng Jiang

Graduate Theses and Dissertations

This study was conducted to examine the inclusion of nature of science (NOS) in popular science writing to determine whether it could serve supplementary resource for teaching NOS. Four groups of documents published from 2001 to 2010 were included in the analysis: Scientific American, Discover magazine, winners of the Royal Society Winton Prize for Science Books, and books listed in National Science Teacher Association's (NSTA) Outstanding Science Trade Books for Students K-12.

First, computer analysis was performed to categorize passages in the selected documents based on their inclusions of NOS. Then, follow-up human analysis was conducted to assess the frequency, …

The Relationship Between Middle Level School Science Programs And A Residential Environmental Learning Center, Ryan Mathew Walker

Graduate Theses and Dissertations

A multiple case study investigation examines the relationship between a residential environmental learning center and six schools that attend their program. Pre-experience interviews were conducted with teachers to gain understanding of how they integrate the residential experience with formal classroom instruction. On-site observations of teacher participation during the program provided insight into how they foster student learning during the experience. A student questionnaire was used to reveal students' perceptions of three areas of interest: 1) most meaningful aspects of the experience, 2) most confusing aspects of the experience and 3) topics they would like to know more about. These data …

Contextual Influences On Small Group Decision-Making: A Field Investigation, Sarah Kathryn Chorley

Graduate Theses and Dissertations

This thesis examines small group decision-making among groups of educators in an elementary school through the Bona Fide Group Perspective, which focuses on a group and its relationships to elements in its context. Twenty-six faculty members were interviewed and 26 meetings were recorded; these were analyzed using thematic analysis. The results indicated contextual, relational, and discursive factors influenced the decision-making process. Most critically, power, status, overlapping group memberships, and competing Discourses shaped the group decision-making process.

Fabrication And Characterization Of Thinner Solid-State Nanopores, Denis Forbi Tita

Graduate Theses and Dissertations

Solid State nanopores that are fabricated by the ion beam sculpting process and electron beam drilling have shown great promise as a sensing device for DNA and protein molecules. Even though biological pores such as the alpha-Haemolysin have been in use for quite some time, the use of solid state Nanopores in single biomolecule detection has been on the rise since the mid 1990s. Solid State nanopores have an advantage over biological pores in that they are more robust, stable, and can be sculpted to any desired size for use in translocation experiments. One of the major challenges in Nanopore …

A Reexamination Of The Eastern Collared Lizard (Crotaphytus Collaris Collaris) In Arkansas, Ashley A. Grimsley

Graduate Theses and Dissertations

Loss of suitable habitat is a threat to species worldwide. Habitat destruction, including loss, change, and fragmentation of habitat, is the leading cause of species extinction. Eastern collared lizards (Crotaphytus collaris collaris) are habitat specialists on glades. Both C. c. collaris and glade habitats are rare and of special concern in the state of Arkansas. Many glade populations have already been extirpated in the Ozarks of Arkansas and Missouri. Increasing knowledge of the distribution, habitat structure, and population dynamics of C. c. collaris is important to ensure the survival of this species in Arkansas.

A literature review of …

Characterization And Consumer Acceptance Of White Striping In Broiler Breast Fillets, Vivek Ayamchirakkunnel Kuttappan

Graduate Theses and Dissertations

White striping is an emerging issue in the broiler meat industry which causes concerns among the producers. The condition is characterized by the occurrence of white striations, parallel to the direction of muscle fibers, mainly in broiler breast fillets and thighs. Fillets can be categorized as NORM (normal or no striping), MOD (moderate) and SEV (severe) depending on the degree of white striping. As a result of few previous research studies on the condition, there is no information available on the impact of white striping on the consumer acceptance and various meat quality attributes. Our hypothesis was that the occurrence …

Livestock Production And Wildlife-Based Tourism: Articulating Land-Use And Policy Conflicts In The Okavango Delta Ramsar Site In Botswana, Nelson Kgamanyane Sello

Graduate Theses and Dissertations

The management of common pool resources and policy conflicts between livestock and wildlife, two land-use types that take place in the same geo-spatial area has been a subject of debate among scholars for decades. This conflict in policies has engendered in communities which are beneficiaries attitudes that are either negative towards wildlife or favorable depending on the benefits they derive from them. This research therefore set out to understand the conflicts in the management of the Okavango Delta Ramsar Site (ODRS) where the OD is situated. The study used the grounded theory to collect and analyze the data in the …

Assessing Knowledge Acquisition Through Lecture And Cooperative Learning: Traditional And Non-Traditional Secondary Students In Agriculture, Beth Ann Jean Bills-Hunt

Graduate Theses and Dissertations

Currently, students entering secondary agricultural education programs have less knowledge and hands-on experience about agriculture than previous generations. Agricultural educators are challenged to vary teaching practices to meet student needs. The purpose of this study was to determine if there is a difference in knowledge acquisition between students enrolled in secondary agricultural education classes taught by cooperative learning and lecture instruction. Additionally, this study explored the knowledge acquisition of traditional and non-traditional secondary agricultural education students and perceptions of instructional methods presented. Eight schools participated in the study. No significant difference was seen in test scores between methods of instruction, …

Evaluation Of Isothiocyanates And Herbicide Programs As Methyl Bromide Alternatives For Weed Control In Polyethylene-Mulched Tomato And Bell Pepper, Pratap Devkota

Graduate Theses and Dissertations

Methyl bromide (MeBr), a Class I ozone –depleting substance, has been banned for ordinary agricultural uses. In the absence of an effective MeBr alternative, weed control is a major challenge for commercial tomato and bell pepper production. Field trials were conducted at Fayetteville, AR, to compare allyl isothiocyanate (ITC), metam sodium, and herbicide programs with the standard MeBr application (mixture of MeBr plus chloropicrin at 67% plus 33%, respectively, hereafter referred to as MeBr) for crop injury, weed control, viable yellow nutsedge tubers, and marketable yield in low–density polyethylene (LDPE) mulched tomato and bell pepper production. In addition, herbicide programs …

Relationship Of Polymorphisms In The Fsh Beta Subunit Gene With Reproduction In Bos Taurus And Bos Indicus Cattle, Amanda Jo Davis

Graduate Theses and Dissertations

Two experiments were conducted to characterize polymorphisms (SNP) in the bovine FSHβ gene promoter region to examine breed differences in SNP, and to determine effects of SNP on reproduction in beef cattle. Experiment 1 - DNA samples were collected from 5 Angus (ANG), 13 Balancer (BAL), & 16 Brahman influenced (BI) bulls. Polymorphisms were identified by sequencing of 3 sequential PCR products from the promoter region revealed 17 SNP & 4 insertion/deletions (INDEL). Semen samples were collected and sperm quality variables determined via computer assisted sperm analysis (CASA) or stained smears. The MIXED procedure for ANG & BAL indicated interactions …

The Silent Arms Race: The Role Of The Supercomputer During The Cold War, 1947-1963, David Warren Kirsch

Graduate Theses and Dissertations

One of the central features of the Cold War is the "Arms Race." The United States and the Union of Soviet Socialist republics vied for supremacy over the globe for a fifty-year period in which there were several arms races; atomic weapons, thermonuclear weapons and various kinds of conventional weapons. However, there is another arms race that goes unsung during this period of history and that is in the area of supercomputing. The other types of arms races are taken for granted by historians and others, but the technological competition between the superpowers would have been impossible without the historically …

Semiconductor Nanocrystals: From Quantum Dots To Quantum Disks, Zheng Li

Graduate Theses and Dissertations

The bottom-up colloidal synthesis opened up the possibility of finely tuning and tailoring the semiconductor nanocrystals. Numerous recipes were developed for the preparation of colloidal semiconductor nanocrystals, especially the traditional quantum dots. However, due to the lack of thorough understanding to those systems, the synthesis chemistry is still on the empirical level. CdS quantum dots synthesis in non-coordinating solvent were taken as a model system to investigate its molecular mechanism and formation process, ODE was identified as the reducing agent for the preparation of CdS nanocrystals, non-injection and low-temperature synthesis methods developed. In this model system, we not only proved …

Effects Of Head Position And Head-Supported Mass On Nerve Function Of The Flexor Carpi Radialis Muscle In Healthy Individuals, Bethany Lauren Shivers

Graduate Theses and Dissertations

Long-term exposure to head-supported mass (HSM) has been linked with spinal degeneration including foraminal stenosis and disc deterioration. Anecdotally, HSM has also been linked to neck and arm pain and muscle atrophy, but nerve function has not been tested specifically. The combined effect of various head positions and HSM may be sufficient to compress the nerve root in aviators and Soldiers during job performance, potentially leading to short- and long-term neuromuscular effects. The Hoffmann (H) reflex, a well-established measure of nerve function, has shown to be sensitive to changes in nerve root space which occurs with different head positions. This …

Flight Period And Species Composition Of Sirex (Hymenoptera: Siricidae) And Associated Deladenus (Nematoda: Neotylenchidae) Within Arkansas Pine Forests, Danielle Keeler

Graduate Theses and Dissertations

The European woodwasp, Sirex noctilio F. (Hymenoptera: Siricidae), which is a known destructive pest of pine in the southern hemisphere was recently discovered in the eastern United States. Before we can understand how S. noctilio may affect pine forests throughout the United States, we need a better understanding of native Sirex and the role they play in the ecosystem. The objectives of this research were to 1) determine species composition and flight period for native Sirex; 2) confirm presence of parasitic nematodes, Deladenus (Nematoda: Neotylenchidae), within adult Sirex; 3) investigate Deladenus parasitism rates; 4) verify the number of Deladenus species …

An Analysis Of The Redox Properties And Stability Of Chlamydomonas Reinhardtii Cytochrome F, Cytochrome C6, And Mutants Thereof, Nicole Lynn Vanderbush

Graduate Theses and Dissertations

This body of work presents mutagenesis studies conducted on two c-type cytochromes from Chlamydomonas reinhardtii. Cytochrome f, a unique c-type cytochrome, is investigated in regards to its redox potential, the dependence of the redox potential, and the thermal stability of the protein. The mutations made were Y1F, Y9F, Y160F, Y160L, R156L, and R156K. The residues that were mutated surround the heme. It was found that, relative to the wild-type, only the Y160L and R156 mutants showed any difference in midpoint potential at pH 7. Wild-type and mutants both had a midpoint potential that was dependent upon pH indicating that none …

Maternal Environment And Fescue Cultivar Effects On Growth, Development, And Fertility Of Beef Heifers, Jennifer Denyse Patterson

Graduate Theses and Dissertations

Eighty Brahman-influenced cows (5.6 BCS) were assigned to graze common bermudagrass (CB) or toxic tall fescue (E+) during a 60-d breeding season. Body condition (BC) was assessed at d 0, 30, and 60 of breeding season. Cows were managed to achieve marginal (4.2 BCS) or good (6.3 BCS) BC during last trimester. Heifer birth and weaning (WW; 7 to 8 mo) weights were recorded. The Angus sired heifers were weighed and randomly assigned to E+ or non-toxic (Novel) tall fescue at 9 to 10 mo of age for 190d. Heifer weight, growth data, and antral follicle count (AFC) were collected …

Plasmonic Pervaporation Via Gold Nanoparticle-Functionalized Nanocomposite Membranes, Aaron Russell

Graduate Theses and Dissertations

Butanol derived from biological feedstocks has significant potential as a liquid fuel source, but the separation methods used in its production can be prohibitively expensive and are therefore currently the subject of extensive research. Pervaporation is a promising membrane process that is effective in butanol separations, but involves a large energy demand. This study examines the possibility of increasing flux and energy efficiency in pervaporation via plasmonic heating of gold nanoparticle-functionalized, polymer nanocomposite membranes (AuNCMs) in lieu of conventional feed heating. An economic analysis demonstrated that plasmonic pervaporation could achieve significant reductions in energy usage and utility cost in butanol …

Determination Of Methionine And Lysine Requirements Of Growing Broilers Using The Ideal Protein Concept, Changji Lu

Graduate Theses and Dissertations

Three experiments were conducted to evaluate the responses of broiler performance to Lysine (Lys) and Methionine (Met) during the starter, grower, and finisher feeding phases. All the experimental diets were formulated based on the Ideal Protein Concept.

Experiment 1 evaluated the responses to Lys and Met on live performance of young broiler chickens from 0 to 18 d of age. The mean amino acid ratios to Lys suggested by literature values were used in the formulation based on the Ideal Protein Concept. Six levels of Lys and eight levels of supplemental Met were used in the diets resulting in a …

What Factors Influence Consumers' Willingness To Purchase And Consume Carbon-Labeled Rice: A Comparative Study Between Arkansas And Belgium, John A. Kelley

Graduate Theses and Dissertations

Climate change is an issue of growing importance around the globe. As global population increases so does attention focused on human contributions to climate change. One major way humans contribute to climate change is through our diets. Agricultural production is a major source of global greenhouse emissions. It has been estimated that food production is responsible for a large majority of the methane and nitrous oxide which is emitted into our atmosphere each year. Carbon footprint labeling has been developed to give consumers a way to lower their footprint and help lower emissions of greenhouse gasses. At least one retailer, …

Performing Literacy: How Women Read The World In The Late Eighteenth-Century British Novel, Amy Hodges

Graduate Theses and Dissertations

This dissertation explores the intersection of sensibility, Social identity, and literacy practices among representations of women readers in four late eighteenth-century British novels. Through an analysis of the authors' use of identity constructs which shaped and were shaped by reading practices, this study documents the rise of Social identity formation as mutually constitutive with the history of reading. The first chapter reveals how Charlotte Lennox's The Female Quixote uses Arabella's follies as education for readers about the corresponding processes of reading their society and reading novels. The second chapter argues that Frances Burney's Evelina considers women's ability to read others …

The Impact Of Selected Forage Legumes On Cattle Performance, Forage Production, And Soil Quality, And Evaluation Of Legume Persistence Under Grazing, Bradley Edward Briggs

Graduate Theses and Dissertations

Interest in substituting legumes for N fertilizer in beef cattle grazing systems has recently increased with rising fertilizer prices. Legumes are well known for their ability to fix atmospheric N and decrease dependence on input of N fertilizer. However, there are still difficulties associated with legume utilization including establishment and persistence. Two experiments were conducted to evaluate legume performance under herbivory. The objective of Experiment 1 was to compare forage production and beef cattle gains from annual ryegrass [Lolium multiflorum (L.)] and bermudagrass [Cynodon dactylon (L.) Pers.] pastures fertilized with N or overseeded with legumes. Gelbvieh × Angus …