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In Vivo Structure-Function Analysis Of Drosophila Robo1, An Axon Guidance Receptor Critical For Midline Repulsive Signaling In The Embryonic Central Nervous System, Haley Brown

Graduate Theses and Dissertations

The repellant ligand Slit and its Roundabout (Robo) family receptors regulate many aspects of axon guidance in bilaterians, including midline crossing of axons during development of the embryonic CNS. Slit proteins are produced by midline cells and signal through Robo receptors expressed on the surface of axonal growth cones to repel axons from the midline. Disruption of Slit-Robo signaling causes ectopic midline crossing phenotypes in the CNS of a broad range of animals, including insects and vertebrates.

Drosophila Robo1 has a conserved ectodomain structure of five immunoglobulin-like (Ig) domains plus three fibronectin (FN) repeats. By utilizing a genomic rescue construct …

A Genome Wide Association Study For Fusarium Head Blight Resistance In Southern Soft Red Winter Wheat, Amanda Holder

Graduate Theses and Dissertations

Fusarium head blight (FHB) is a disease of small grains caused by the fungal pathogen Fusarium graminearum. FHB poses potential economic losses and health risks due to the accumulation of the mycotoxin deoxynivalenol (DON) on infected seed heads. The objectives of this study are: 1) evaluate soft red winter wheat (SRWW) lines for resistance to FHB in terms of resistance to initial inoculum (incidence); resistance to spread within the head (severity); resistance to DON accumulation; and resistance to Fusarium damaged kernels (FDK), 2) determine the frequency and effect of known FHB resistance genes and quantitative trait loci (QTL), and 3) …

Unravelling The Layers Of Cell Wall Synthesis And Function In Rice, Ritu Mihani

Graduate Theses and Dissertations

The plant cell wall is of critical importance to plant growth and survival, functioning in maintaining structural integrity, supporting cell expansion, and acting as the first line of defense in response to biotic and abiotic stresses. The major components of the cell wall are cellulose, hemicelluloses, lignin, and pectin. Recent focus on the transcriptional machinery regulating cell wall biosynthesis in plants has revealed many key transcription factors responsible for orchestrating cell wall deposition. However, many of these TFs act redundantly and work coherently with a suite of TFs to activate the cell wall biosynthetic machinery. Heterologous expression of TFs is …

Program Evaluation Of Magnet Program Implementation, Tionanatasha Kairecia Harris

Graduate Theses and Dissertations

The purpose of this study was to examine the fidelity of the implementation of a magnet program at an area intermediate rural school. A case study approach was used to conduct the study, based on observations and perceptual information. The following research questions were developed to address the problem of this study: (a) How does the magnet curriculum affect the delivery of magnet instruction in core content areas? (b) How do participants perceive the strengths and weaknesses of how the magnet program was implemented? The quantitative research consisted of classroom observations to determine if magnet curriculum was being implemented in …

Digital Palace Of Nestor: Assessing Mycenaean Palatial Complex Construction Of Socio-Political Status And Navigation Through Architecture, Caleb Ward

Graduate Theses and Dissertations

Because architecture necessitates the conscious planning of space, its consequences for navigation and socio-political status are equally deliberate and have indirect effects. This research combines experiential and spatial syntax techniques to gain a deeper understanding of how Mycenaeans shaped space to construct status and navigation in the Palace of Nestor at Pylos. Using a digital reconstruction of the palace ensured the most accurate experiential data by utilizing a whole, albeit virtual, version of the site. Without employing a digital reconstruction, the only experiences with the site would occur in the ruinous, actual site preventing complete experiences with how the site’s …

Non-Target-Site Based Tolerance To Herbicides In Amaranthus Palmeri, Reiofeli Algodon Salas-Perez

Graduate Theses and Dissertations

Palmer amaranth, one of the most aggressive and damaging broadleaf weeds in the USA, has evolved resistance to multiple herbicide modes of action. The overall objective of this research was to elucidate the mechanisms by which Palmer amaranth adapt to herbicide selection stress. This research aimed (1) to evaluate the efficacy of fomesafen, glufosinate, glyphosate and trifloxysulfuron to Amaranthus populations; (2) identify candidate genes for endowing tolerance to glufosinate; (3) investigate the involvement of non-target-site resistance (NTSR) mechanism in an ALS-resistant population; and (4) to examine the molecular basis of resistance to PPO inhibitors in Palmer amaranth populations from Arkansas. …

Best Practice: Bringing The Elements Of Effective Practice To The College Writing Classroom, Jonathan Montgomery Green

Graduate Theses and Dissertations

Studies of college writing students suggest that many students associate writing ability with innate talent rather than sustained, deliberate practice. As a result, these students may lack the motivation to improve their writing abilities, leading to a vicious cycle in which they come to increasingly resent writing as a curricular and extracurricular activity. This dissertation argues that the elements of effective practice as outlined by cognitive psychology are equally applicable to writing as they are to skills such as music and that convincing students of the “practice-ability” of writing may improve their motivation to improve their writing abilities.

The dissertation …

Examination Of Shape Variation Of The Calcaneus, Navicular, And Talus In Homo Sapiens, Gorilla Gorilla, And Pan Troglodytes, Nicole Lynn Robinson

Graduate Theses and Dissertations

Analyses of morphological integration among primates commonly focus on relationships between the face, braincase and base of the skull, as well as the upper and lower dentition, and the within portions of the post-cranial skeleton. Despite the prominence of these studies, the associations between the bones of the foot and their articular surfaces have largely been ignored among primates, even though the foot demonstrates high degrees of variation and modification. This variation offers an ideal opportunity to study the relationship between morphology and locomotion. Because the talus, calcaneus and navicular act together to stabilize the foot in locomotion and form …

Sacral Morphology Of Prehensile-Tailed Primates In Relation To Biomechanical Loading, Hannah Grace Showalter

Graduate Theses and Dissertations

The few available comparative studies of prehensile tail anatomy in primates have established that several features of the caudal vertebrae are associated with adaptation to the increased loading of the tail during prehension. Given that the caudal vertebrae are anchored to the sacrum, it stands to reason that sacral morphology should also covary with tail prehensility. Convergent evolution of prehension in ateline and cebine primates and clear variation in the use of tails among taxa raises questions not only of how sacral morphology differs between prehensile and non-prehensile taxa, but whether different prehensile-tailed taxa evolved the same solutions to the …

Examining The Relationship Between State Anxiety And Vestibular And Ocular Motor Impairments And Symptoms In High School Athletes With Concussion, Mallory Kathleen Mcelroy

Graduate Theses and Dissertations

Anxiety has been associated with vestibular and ocular motor impairment in the general population. However, there is limited research regarding the connection between the vestibular and ocular motor systems and anxiety following sport-related concussion (SRC). OBJECTIVE: The purpose of this study is to compare state anxiety between concussed adolescent male and female athletes with and without vestibular and ocular motor impairments and symptoms. DESIGN: Prospective, repeated measures SUBJECTS: Thirty adolescent athletes between the ages of 15-18 years, diagnosed with a SRC completed the STAI-State at initial and medical clearance clinical visit. These adolescent athletes were categorized into vestibular and ocular …

Evaluation Of The Effects Of Formaldehyde On Growth Parameters Of Broiler Chicks, Paula Johnson

Graduate Theses and Dissertations

Formaldehyde has been used as a disinfectant in poultry hatching cabinets to aid in controlling key pathogenic organisms, such as Salmonella and Escherichia coli (E.coli). There is some evidence that prolonged exposure of chicks to formaldehyde can reduce tracheal ciliary function and thus reasons to believe that exposure to formaldehyde, in the absence of pathogen challenge, may reduce chick vitality. It has been found that elevated temperatures during incubation may adversely affect body weights of broiler chicks, as well as post-hatch environmental heat stress on performance in poultry. Post-hatch environmental heat stress has been shown to impact performance in poultry. …

Applications Of Reservoir Limnology Theory And Steady-State Modeling To Eutrophication Management In Beaver Lake, Arkansas, Matthew Rich

Graduate Theses and Dissertations

Reservoir limnology theory predicts that phytoplankton biomass (PB) is greatest in riverine-transition zones and least in lacustrine zones leading to an inverse pattern in water clarity. These theoretical patterns were utilized to create a statistical model of chlorophyll-a (Chl-a), an indicator of PB, and Secchi transparency (ST), an indicator of Chl-a, in Beaver Lake, Arkansas, a 12,800-ha reservoir, in order to hindcast historical conditions. Sampling for Chl-a, ST, and photic depth occurred semimonthly at 12 locations along a 78-km transect from the river inflow to the dam during the 2015 growing season. The ratio of Chl-a and ST measured at …

Pre-Season Vitamin D And Iron Levels As A Predictor Of Musculoskeletal Injury In Division I Athletes, Mariellen Katherine Veach

Graduate Theses and Dissertations

Context: Pre-season testing that includes the analysis of micronutrient serum levels in the blood has become a routine part of pre-participation examinations in collegiate football. Objective: Assess the predictability of vitamin D and iron serum levels as indicators of future injury during a subsequent competitive season for lower extremity sprains, strains, and fractures. Additionally, determine the effectiveness of vitamin D supplementation on increasing serum 25(OH)D levels and preventing injury. Design: Cohort Study. Setting: National Collegiate Athletic Association Division I football program. Participants: Football athletes (n=349) who underwent pre-participation examinations and participated in at least one of three competitive football seasons. …

Evaluation Of The Efficacy Of A Candidate Turkey Dermatitis/Cellulitis Oil Emulsion Vaccine On Immune Response, Morbidity, And Mortality Under Laboratory And Commercial Conditions, Brittany Danielle Graham

Graduate Theses and Dissertations

Alpha-toxigenic Clostridium septicum (CS), the cause of turkey cellulitis, results in devastating mortality with high costs for the industry. Various vaccinations have been evaluated to prevent this disease with moderate success. Ability of a CS bacterin-toxoid, in conjunction with adjuvants such as aluminum hydroxide, mannoslyated chitosan, or a water-in-oil Seppic Montanide 71 R VG adjuvant (OE) to induce immunity was evaluated in a 7-week study (Experiment 1). Poults (20/group) were vaccinated day-of-hatch, boosted at 5 weeks-of-age and compared to unvaccinated controls. Antibody titers were determined by ELISA for all experiments. In experiment 1, initial vaccination with OE resulted in significantly …

I, Myself, And Me, The Human Being, David Manuel Cajias

Graduate Theses and Dissertations

In this project are advanced two ways of seeing the ordinary human being with the aim of understanding who he is: namely, from the perspective of his personal identity and from the point of view of his self-conception. The chapters included in the first part are meant to treat the issue of personal identity from a practical perspective, whereas the ones included in the second part intend to assess the utility of self-conception from a phenomenological standpoint. Ultimately, I bring together these two perspectives into a unitary understanding of the human being in the context of his everyday life.

An Investigation Of Biological Carbon Sequestration At The Pea Ridge National Military Park, Dorine Reed Bower

Graduate Theses and Dissertations

The direct correlation between increasing levels of atmospheric CO2 and global temperatures is now irrefutable. A 50% increase in atmospheric CO2 levels from a pre-industrial level of 270 ppm to a present-day level of 405 ppm, has resulted in documented record temperatures and a concomitant rising of sea levels from melting ice caps.

The ability of biological/terrestrial ecological systems to store atmospheric carbon is a viable option in the effort to mitigate the climate impacts of rising anthropogenically-caused greenhouse gas emissions. Components of the vegetation and soils in the Pea Ridge National Military Park (the Park) were examined for carbon …

3d Printed Pcu/Uhmwpe Polymeric Blends For Artificial Knee Meniscus, Raissa Araujo Borges

Graduate Theses and Dissertations

3D printing was used to fabricate porous artificial knee meniscus material from biocompatible polymeric blends of polycarbonate-urethane (PCU) and ultra-high-molecular-weight polyethylene (UHMWPE) to enable “weep” lubrication that mimics the native meniscus. 3D printed and molded pure PCU, as well as molded PCU and UHMWPE, were used for comparison. Preliminary printing was done to evaluate the impact of process parameters on the results. The samples were subject to a variety of rotational oscillating friction and wear tests under simulated body fluid and loading conditions to replicate the natural motion of the knee. Results show that 3D printed PCU samples yielded a …

Investigating Fate Of Silver Nanoparticles In Wastewater Biofilms, Connie Marie Walden

Graduate Theses and Dissertations

As industrial advances make everyday life easier for human kind, the processes by which we need to maintain sanitary conditions for both water and wastewater treatment will become increasingly complex. Innovations in food packaging and textile design incorporate engineered nanoparticles (ENPs) to increase antimicrobial properties of clothing, maintain product color, and keep food in packaging from spoilage. For most products, ENPs released will enter the sanitary sewer system, and ultimately wastewater treatment plants. Biofilms grow universally on surfaces where a protective layer of extracellular polymeric substances (EPS) shields attached cells from stressors. In wastewater treatment, complex biofilms are utilized as …

Identifying Genetic Factors Influencing Sperm Mobility Phenotype In Chicken Using Genome Wide Association Studies, Primordial Germ Cell Transplantation, And Rnaseq., Sohita Ojha

Graduate Theses and Dissertations

Sperm mobility is a major determinant of male fertility in chicken. In spite of low heritability of reproductive traits, sperm mobility has high heritability index which suggests presence of quantitative trait loci (QTLs) governing the trait. Our research focused on three objectives: i) to identify the QTLs affecting low mobility phenotype in chicken, ii) to understand the impact of Sertoli-cells and germ cells interactions in influencing the mobility phenotype and iii) to identify the genes and gene networks differentially expressed in male and female PGCs. To detect the QTLs, genome wide association studies (GWAS) was conducted which revealed the presence …

Effects Of Pre-Chiller Temperature On The Microbial Ecology Of Whole Bird Carcass Rinses, Rachael Elizabeth Blevins

Graduate Theses and Dissertations

Upon entering a poultry processing facility, birds are already contaminated with a variety of microorganisms. It is the responsibility of the processor to reduce these numbers to deliver a wholesome product to customers. This is not an easy task as there are ample opportunities for further microbial contamination. Some of these opportunities are obvious. For example, any areas where contaminants could be washed off one bird and onto another are always an area for concern, i.e. the scalder or the chiller. There are numerous opportunities for contamination that are not so obvious. These incidents of contamination are not necessarily due …

Habitat Ecology, Trophic Interactions, And Distribution Of Endangered Himalayan Musk Deer In The Nepal Himalaya, Kapil Kishor Khadka

Graduate Theses and Dissertations

This dissertation seeks to explore and assess the habitat selection, trophic interactions and distribution of Himalayan musk deer. Chapter one deals with seasonal diet analysis of musk deer along with the overlap in consumption with livestock during summer. Microhistological technique was employed to assess dietary consumption. Results showed that Abies spectabilis, Pinus wallichiana, and Berberis species constituted the major portion of musk deer’s diet. Dietary breadth measured by the Shannon index was found higher in winter compared to summer. Although musk deer and livestock shared a considerable number of plant species in their diets, the consumption however was significantly different …

Modelling The Impact Of National Development Strategies For The East African Rice Sector, Florence Muthee

Graduate Theses and Dissertations

The 2008 food crisis prompted many food importing nations to reconsider the need to be self-sufficient especially in their staple food needs. This awakening led to the launch of the Coalition for Africa Rice Development (CARD) initiative with a goal to double rice production in Africa. Under the CARD umbrella member countries drafted individual National Rice Development Strategies (NRDS). This study is a quantitative assessment of four East African countries’ NRDS: Kenya, Rwanda, Tanzania and Uganda within dynamic global rice economy models. The NRDS targets and strategies are not realistic and included under estimation of rice consumption for Kenya, an …

Horizontal Transmission Of Helicoverpa Armigera Nucleopolyhedrovirus (Hearnpv) In Soybean Fields Infested With Helicoverpa Zea (Boddie), Joseph Lee Black

Graduate Theses and Dissertations

Helicoverpa armigera Nucleopolyhedrovirus (HearNPV) is a commercially available viral biopesticide that targets Heliothines, including Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), the most damaging pest of soybean (Glycine max (L.) Merrill) in the Mid-South. Previous formulations of HearNPV have been well studied; however, no research has been published on current formulations. The first objective of this thesis was to assess the rate of horizontal transmission of HearNPV in a soybean field infested with H. zea when HearNPV was applied as a bio-insecticide, and to identify arthropods that are important obligate carriers in dissemination. HearNPV spread 200 feet in 3 fields, and was …

Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen

Graduate Theses and Dissertations

Global importance of forests is difficult to overestimate, given their role in oxygen production, ecological roles in nutrient cycling and supporting numerous living species, and economic value for industry and as recreational zones. Fitness of the forest-forming trees strongly depends on microbial communities associated with tree roots. In particular, fungi impact tree fitness: mycorrhizal species provide water and nutrients for the trees in exchange for C, endophytic fungi play key roles in host defense against pathogenic organisms, and saprotrophic fungi decompose dead organic matter and facilitate nutrient cycling. In addition, pathogenic fungal species strongly affect forest fitness. Despite their importance, …

Development And Characterization Of Rice Genotypes For Water Use Efficiency And Drought Resistance, Anuj Kumar

Graduate Theses and Dissertations

Rice, the second largest staple food crop, uses 30% of global fresh water to complete its life cycle worldwide. Water deficits worldwide have become a serious problem affecting rice growth and ultimately grain yield. To solve the water problem globally, improvement of water use efficiency (WUE) and other drought resistance (DR) traits in rice genotypes would be a useful strategy using advanced genomics tools. In this study, our objectives were to 1) analyze phenotypes of the USDA rice mini-core collection (URMC) for WUE and DR related traits, 2) correlate drought response phenes for physiological traits and grain yield in the …

Evaluation Of The Impact Of Tart Cherries Polyphenols On The Human Gut Microbiota And Phenolic Metabolites In Vitro And In Vivo, Alba Claudia Mayta-Apaza

Graduate Theses and Dissertations

Tart cherries are polyphenol abundant stone fruits claimed to exert health benefits further of its nutritional properties. The abundant phytochemicals content in tart cherries also referred as dietary polyphenols have been considered as an effective natural antioxidant when added in daily diet. However, it has been hypothesized the intervention of gut microbiota on the overall functionality of such compounds. This thesis contains a wide-ranging literature review focused on tart cherry as a crop, current market, functional food, and several health benefits. Furthermore, the research done describes and in vitro and in vivo assays of a short-term dietary intervention of tart …

A Molecular Diagnostic Survey Of Pathogens And Parasites Of Honey Bees, Apis Mellifera L., From Arkansas And Oklahoma, Dylan Cleary

Graduate Theses and Dissertations

The health and viability of colonies of the honey bee, Apis mellifera, in the United States have fluctuated dramatically over the past decade. This poses a substantial threat to agricultural production in this country. Currently, no single factor has been identified for this decline. Rather, it has been suggested that the interaction between multiple biotic and abiotic stressors may be responsible. Among these factors are pesticides, habitat loss, climate and weather, parasites and pathogens, and colony management techniques. For this reason, it is important to examine the prevalence of honey bee parasite and pathogen infection at the state level in …

Shallow Aggregate Ebb-And-Flow System For Greenhouse Lettuce Production, Joseph Chidiac

Graduate Theses and Dissertations

A novel soilless technique for the production of lettuce was developed and evaluated for its viability for ornamental greenhouse growers adapting their ebb-and-flood irrigation benching systems to diversify into growing lettuce, without having to purchase the conventional nutrient film technique (NFT) or deep flow technique (DFT) hydroponic systems. The experimental design was a three by four factorial, with three treatments for aggregate depth (19, 38, and 57 mm) and four treatments for irrigation frequency (once every 1, 2, 4, or 8 hours), for a total of twelve treatment combinations. Each treatment was replicated three times in a randomized complete block …

New Technologies For Evaluating Putting Green Surface Characteristics, Daniel Patrick O'Brien

Graduate Theses and Dissertations

Golf course putting greens require a high level of inputs predicated on timely, well informed decisions. Putting green quality is ultimately defined by performance of the turfgrass, and this performance encompasses both (i) the health and vitality of the turfgrass plants, and (ii) the ability of the turfgrass to exist as a playing surface, as it interacts with the golf ball. For golf course superintendents, accurately and efficiently assessing moisture levels and nutrient status are critical for guiding maintenance practices. This research sought to examine new ways for measuring each of these parameters, and compared them to ground-truth data and/or …

Bacterial And Archaeal Nitrifier Communities After Seven Years Surface Ground Cover And Nutrient Management In An Orchard Soil, Mashael Albalawi

Graduate Theses and Dissertations

Nitrification is oxidation of ammonia to nitrite and subsequently to nitrate. The rate limiting step of nitrification, ammonia oxidation to nitrite, was thought for many years to be carried out primarily by ammonia oxidizing bacteria (AOB). However, using molecular techniques and investigating the amoA gene, ammonia-oxidizing archaea (AOA) were discovered. Understanding how long-term application of surface ground covers and organic fertilizers to perennial systems affect microbial communities is critical for sustainable soil management. An organically managed experimental apple orchard soil received seven years (2006 – 2013) of annual, surface applications of poultry litter or commercial fertilizer compared to no fertilizer …