Life Sciences Commons^™

Ecological Importance Of Invader Source Population And Disturbance In Aquatic Invasions, Nicole Elizabeth Graham

Graduate Theses and Dissertations

Invasive species are a global problem and their effects on recipient ecosystems may be mediated by disturbance and intraspecific variation. Crayfish can substantially influence stream structure and function, and invasive crayfish often have differential impacts than native crayfish in aquatic ecosystems. Since species traits often vary across a distribution, it is possible that invasive crayfish from different source populations may have distinct impacts on recipient ecosystem structure and function. In the Ozark Highlands of Arkansas and Missouri, USA, invasive O. neglectus (the Ringed Crayfish) may be leading to the displacement of native O. eupunctus (the Coldwater Crayfish). The objective of …

Efficiency And Competitiveness Of Kosovo Raspberry Producers, Rina Vuciterna

Graduate Theses and Dissertations

Raspberry production is a growing industry in Kosovo. In addition to private investments, this growth has been supported by grants, subsidies, and direct investment from international donor organizations and governmental institutions. At present, most of the commercially produced raspberries in Kosovo are produced on small farms, harvested by farmers and packed manually by collection centers, and then sold in frozen form for the export market. The long-term viability and continued growth of raspberry production in Kosovo depends on the industry being able to compete in export markets and hold its own against production regions in Poland, Serbia, and Russia. Our …

Influence Of Exogenous Phytase Level And Interaction With Supplmental Xylanase On Live Performance And Phosphorus Retention Of Broilers, Peyton Gilbert

Graduate Theses and Dissertations

Two 3-week experiments were conducted, each using 480 day-old male broilers placed randomly among 96 battery cages (5 per cage; 680cm2 per bird), to evaluate the influence of phytase supplementation, with or without supplemental xylanase, on bird performance. Individual body weights and cage feed weights were taken on days 0, 7, 14, and 21, and mean BW, body weight gain (BWG), feed intake (FI), and FCR over each period calculated. Mortality was recorded daily and used to calculate livability and adjust FCR in both trials. In trial 2, excreta was collected by cage from 14 to 21 days for bone …

Assessment Of The Arkansas Horse 4-H Program: Perspectives From Multiple Stakeholders, Fawn Lee Kurtzo

Graduate Theses and Dissertations

Assessment of the Arkansas horse 4-H program utilized stakeholders’ perceptions to describe inputs, outcomes, preferences and impacts provided by the Arkansas Cooperative Extension Service. Stakeholders’ perceptions were captured through three studies. Studies included the following: a pre- and post-test evaluation of the 2016 summer horse camp, purposive interviews with county agents (n = 6), volunteer leaders (n = 4), and parents (n = 4) of horse 4-H clubs, and a statewide survey provided to Extension staff (n =26) and volunteer leaders (n = 28) affiliated with horse 4-H clubs.

The 2016 summer camp evaluation found the goals to improve horsemanship, …

Thylakoid Protein Targeting/Insertion By A Signal Recognition Particle In Chloroplasts, Priyanka Sharma

Graduate Theses and Dissertations

Protein targeting is a fundamental cellular process that directs proteins from their site of synthesis to the site where they function. The signal recognition particle (SRP) dependent targeting pathway is conserved in both eukaryotes and prokaryotes where it co-translationally targets polypeptide chains emerging from ribosomes to the endoplasmic reticulum (eukaryotes) or cytoplasmic membrane (prokaryotes). A structurally unique form of SRP is found in chloroplasts where it functions to post-translationally bind and target a subset of integral thylakoid membrane proteins, the light harvesting chlorophyll binding proteins (LHCPs). Mature LHCPs bind chlorophyll a/b and function in photosynthetic light capture. Like many other …

Evaluation And Association Analysis Of Cowpea Salt Tolerance, Waltram Second Ravelombola

Graduate Theses and Dissertations

Cowpea [Vigna unguiculata (L.) Walp.] (2n=2x=22) is a leguminous crop providing inexpensive protein for human consumption that can be grown worldwide. Salinity is one of the major threats to cowpea production, particularly in semi-arid regions of Africa. Salinity significantly affects seed germination and decreases pod yield in cowpea. However, little has been done to provide farmers salt-tolerant cowpea cultivars. Knowledge on the genetics of cowpea salt tolerance is very limited. This study aimed to:(1) evaluate cowpea salt tolerance at germination stage, (2) evaluate cowpea salt tolerance at seedling stage, (3) conduct an association study for cowpea salt tolerance at germination …

Decision Support Software For Palmer Amaranth Weed Control, Karen Renee Lindsay

Graduate Theses and Dissertations

Herbicide-resistant Palmer amaranth [Amaranthus palmeri (S.) Wats.] has been identified as one of the most troublesome weeds, specifically for corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean [Glycine max (L.) Merr.] producers in the southern United States. The use of herbicide technology remains the most widely used method of weed control, despite the evolution of herbicide-resistant Palmer amaranth. Therefore, a need currently exists for research and extension education to encourage the adoption of Integrated Pest Management (IPM) to address the problem of herbicide-resistant Palmer amaranth in the southern United States. By equipping crop producers, educators, and weed management …

Economic Assessment Of A Highly Pathogenic Avian Influenza Outbreak In Washington And Benton Counties In Arkansas, Antonio Beitia

Graduate Theses and Dissertations

Highly Pathogenic Avian Influenza (HPAI) presents a substantial economic risk to the poultry industry. Domesticated fowl contract HPAI initially through exposure, direct or indirect with migratory waterfowl and outbreaks can result in significant economic losses to growers and the poultry industry at large. A HPAI outbreak occurred in Minnesota and Iowa and spread across over 13 other states in 2014 and 2015. This caused an estimated $1.6 billion in losses (CDC, 2016) and led to shortages of eggs and turkeys together with elevated prices (Anni et al. 2005). Even small outbreaks of HPAI inflict substantial damages as USDA-APHIS guidelines necessitate …

A Genetic Analysis Of Nuclear Functions Of The Lipin Protein In Drosophila Melanogaster, Xeniya Rudolf

Graduate Theses and Dissertations

Lipins are a family of proteins that have critical functions in the control of fat storage and energy homeostasis. Biochemically, lipins have two functions. They provide an enzymatic activity (phosphatidate phosphatase or PAP activity) in the glycerol-3 phosphate pathway that leads to the production of storage fats (triacylglycerols). In addition, they play a role in the regulation of genes in the cell nucleus as transcriptional co-regulators. The PAP activity of lipins has been widely studied in a number of organisms. However, the transcriptional co-regulator function is not as well described in the literature. The transcriptional function of lipins depends on …

Rice Value Chain Development And Policy Sequencing In Southern Africa, Sandratra M. Razafinjoelina

Graduate Theses and Dissertations

In the wake of the 2008 food crisis, net food importing countries questioned the reliance on the volatile world market to meet their food demand. Consequently, the necessity to be selfsufficient returned to the forefront of national priorities. In Africa, the Coalition for African Rice Development (CARD) initiative was initiated and aimed to double rice production in the continent by 2018, with the eventual goal of achieving self-sufficiency in rice production. To attain this goal, each of the 23 CARD member countries drafted a comprehensive value chain upgrading strategy called the National Rice Development Strategy (NRDS). This study intends to …

Using Rb-Tnseq To Analyze Natural Variation In Saccharomyces Cerevisiae, Syed Raza Mahmood

Graduate Theses and Dissertations

One of the main challenges in biology today is the characterization of millions of genes of unknown function being continuously identified in sequencing studies. Transposon mutagenesis is a technique that has been widely used for annotating gene function and has now been combined with next-generation sequencing (Tn-Seq) to assess mutant fitness on a genome wide basis. However, Tn-Seq approaches are often constrained by laborious library preparation protocols which limit the number of organisms or conditions that can be assessed. Random bar code transposon-site sequencing (RB-TnSeq), is a transposon sequencing technique that streamlines library preparation and increases the throughput of mutant …

Effects Of Cover Crop Treatments On Apple Trees, Jennifer Billig

Graduate Theses and Dissertations

Ground cover management systems affect soil quality and health and thereby orchard growth and productivity. There have been few studies in the southern US on the effects of managed drive-rows using cover crops as part of a sustainable apple orchard management system. A field study used treatments of 1) seasonal legumes (cowpea [Vigna unguiculata] and crimson clover [Trifolium incarnatum]), 2) seasonal grasses (millet [Setaria italic] and annual rye [Lolium multiflorum]), or 3) unmanaged natural vegetation drive row plantings, with mowed vegetation blown into the tree row as mulch (mow/blow) nested variable. The legume crop cycles produced more than twice as …

The Use Of Probiotics To Control The Microbial Load Present In Commercial Broiler Chicken Hatch Cabinets As An Alternative To Formaldehyde Fumigation, Lucas Elzie Graham

Graduate Theses and Dissertations

Formaldehyde has been used for decades as a disinfectant in the poultry hatchery. Hatch cabinets are treated with formaldehyde to control the microbial bloom that occurs inside of the hatch cabinet as the hatch progresses. Even with formaldehyde being a known human carcinogen and the detriment that it has on living creatures millions of chicks are exposed to formaldehyde in the hatch cabinet. In these experiments we tested a lyophilized probiotic spray inside of the hatch cabinets from day nineteen to day twenty one to control the microbial bloom that occurs. Hatch cabinet environments were sampled in six experiments. Media …

In Ovo Evaluation Of Floramax-B11 On Marek's Disease Hvt Vaccine Protective Efficacy, Hatchability, Microbiota Composition, Morphometric Analysis, And Salmonella Enteritidis Infection In Broiler Chickens, Kyle Dean Teague

Graduate Theses and Dissertations

It has previously been shown that effective probiotics can accelerate gut maturation and the development of a normal microflora in poultry. This results in increased resistance to enteric pathogens encountered by chicks early in life. Our objective in experiments 1 and 2 was to evaluate the effect of in ovo administration of FloraMax®-B11 (FM) on Marek’s disease (MD) herpesvirus of turkeys (HVT) vaccine protective efficacy. In Exp. 1, day 18 White Leghorn embryos were randomly distributed in four groups, 1) HVT vaccinated, no MDV challenge, 2) HVT + FM vaccinated, no MDV challenge, 3) HVT vaccinated, challenge with virulent MDV, …

Exploring Winery Operation As A Diversification Option For Native American Tribal Enterprises, Randi M. Combs

Graduate Theses and Dissertations

The purpose of this research is to examine the perceptions of tribal members regarding the strengths, challenges, and opportunities presented by tribal winery operation. Specifically, issues of business diversification, marketing, perceived barriers to success, potential benefits to the tribe, and the role of agriculture in the preservation of tribal heritage were considered. A modified mixed-methods exploratory sequential research model was used to collect and organize data in two phases. Phase 1 quantitative data was used to inform the development of a Phase 2 qualitative interview protocol. Phase 1 found a significant relationship between a higher income level and a lower …

Central Role Of Vasotocin In The Neuroendocrine Regulation Of Stress Responses And Food Intake In Chickens, Gallus Gallus, Gurueswar Nagarajan

Graduate Theses and Dissertations

It is well known that arginine vasotocin (AVT) in birds is involved in physiological homeostasis such as cardiovascular, osmotic regulation as well as reproductive functions. Pertinent to these physiological functions, AVT immunoreactive (-ir) neurons in the hypothalamus have been found associated with hemorrhage, dehydration, oviposition and other physiological regulation. Evidence, however, suggests that AVT also plays significant roles in modulating behavior, memory, stress, and food intake. This dissertation research addresses the latter two neuroendocrine functions of AVT in detail within the chicken brain. First, the functional role of AVT-ir neurons in conjunction with corticotropin releasing hormone (CRH)-ir neurons in the …

Flight Activity, Oviposition Pit Distribution, And Emergence Densities Of Monochamus Titillator And M. Carolinensis In The Ozark-St. Francis National Forest In Arkansas, Jake Bodart

Graduate Theses and Dissertations

Monochamus (Coleoptera: Cerambycidae) are a genus of longhorn beetles commonly known as pine sawyers. They have a worldwide distribution coincident with pines (Pinaceae) and are vectors of the pinewood nematode (Bursaphelenchus xylophilus). In the United States, there are eight known Monochamus species and they have a sympatric distribution with at least one other Monochamus species throughout their range. Monochamus are known to attack stressed, dead, and dying conifers especially pines. In the Ozark- St. Francis National Forest in Arkansas, there are two species of pine sawyers and they share this sympatric distribution observed throughout the United States, M. titillator (southern …

Value Of Cover Crops In Suppressing Weeds And Protecting Cotton Yields And Likelihood Of Residual Herbicide Carryover To Cover Crops, Matheus Gabriel Palhano

Graduate Theses and Dissertations

Weed-resistance management has become a topic of concern for modern agriculture. Cost related to herbicide usage has increased greatly due to evolution and proliferation of resistant weeds. Therefore, experiments were conducted to investigate the potential for using cover crops to suppress problematic weeds in cotton as well as chemical options for cover crop dessication, and sensitivity of cover crops to residual herbicides were evaluated. No differences were observed for cereal rye biomass production and consequently weed suppression between broadcast and drilled planting methods. Total amount of cover crop biomass was vital to effectively suppress weeds. Hence, of the cover crops …

Characterization Of The Rnap Binding Sites On A Λ Dna Using A Solid State Nanopore Combined With A Tuning Fork Force Sensing Probe Tip, Harpreet Kaur

Graduate Theses and Dissertations

In this dissertation, the binding positions of RNAP holoenzyme on a λ DNA are characterized using an apparatus that integrates a Solid State Nanopore with a Tuning Fork based Force sensing probe (SSN-TFFSP). The SSN-TFFSP system combines the measurement of ionic current through a solid-state nanopore with a DNA tethered probe tip. The position of the tip is sensed by a tuning fork force sensor and is controlled with a nanopositioning system. With this apparatus, translocation speed of DNA through solid state nanopores has been brought down to 100 μs/base. Such a controlled movement of DNA through a solid state …

The Effect Of Insects On Seed Set Of Ozark Chinquapin, Castanea Ozarkensis, Colton Zirkle

Graduate Theses and Dissertations

Ozark chinquapin (Castanea ozarkensis), once found throughout the Interior Highlands of the United States, has been decimated across much of its range due to accidental introduction of chestnut blight, Cryphonectria parasitica. Efforts have been made to conserve and restore C. ozarkensis, but success requires thorough knowledge of the reproductive biology of the species. Other Castanea species are reported to have characteristics of both wind and insect pollination, but pollination strategies of Ozark chinquapin are unknown. Experiments were conducted to determine the influence of insects on successful pollination of C. ozarkensis, as measured by production of burs and seeds. Exclosure treatments …

The Effect Of Omega-3 Fatty Acids On Energy Metabolism, Energy Intake, And Metabolic Response In Normal Weight And Overweight And Obese School Aged Children (8-12 Years), Charlayne Mitchell

Graduate Theses and Dissertations

Background: Obesity is a major health concern in the United States. Omega-3 fatty acids (O3FA) have been observed to improve metabolic health and therefore might be useful in treatment of obesity. However, little is known regarding the effect of O3FA on school aged normal weight and overweight children.

Objective: The objective of this thesis was to determine if habitual intake of O3FA at breakfast improves energy metabolism, appetite, and metabolic response in overweight and obese school-aged children.

Design: Twenty healthy, normal weight (NW; n = 11) and overweight (OW; n = 9) children aged 8-12 years were randomly assigned to …

Where In The World Are Pallas's Fish Eagles? Migration And Ecology Of Haliaeetus Leucoryphus In Asia, Marla Lynn Steele

Graduate Theses and Dissertations

Pallas’s Fish Eagle (Haliaeetus leucoryphus) is the Northern Hemisphere’s least understood eagle species. Virtually nothing is known concerning the species’ ecology. Historically, Pallas’s Fish Eagles were expected to breed in three separate populations in Mongolia, China, and India and was considered one of the most common raptors in Asia prior to the 1900’s. However, by 1960’s major declines were observed. The species is currently listed as “globally vulnerable” by the International Union for the Conservation of Nature (IUCN) Red List. The current study examined over a century of Pallas’s Fish Eagle observation data to determine occupancy and detection rates throughout …

Examining Fear Of Re-Injury In High School Athletes With Sport-Related Concussion, Melissa Nicole Anderson

Graduate Theses and Dissertations

Recent consensus statements have advocated for research on the emotional sequelae that is associated with sport-related concussion (McCrory et al., 2012). However, changes in fear of re-injury throughout SRC recovery are understudied. The purpose of this study was two-fold: 1) to describe fear of re-injury in high school athletes with SRC, and 2) to document changes in fear of re-injury throughout SRC recovery. This study addressed several exploratory questions regarding fear of re-injury in high school athletes with SRC that pertain to identifying predictors of fear of re-injury as well as examining the relationship between fear of re-injury and locus …

Characterization Of Candidate Compound For Control Of Barnyardgrass And Other Troublesome Weeds In Rice, Michael Ryan Miller

Graduate Theses and Dissertations

Barnyardgrass remains one of the most difficult weeds to manage in rice. As herbicide resistance in this species, as well as others, continues to increase new control options are needed. Dow AgroSciences recently discovered and is developing a new herbicide for rice which is the primary focus of this research. Experiments were conducted to characterize this new herbicide for its use and effectiveness in midsouthern U.S. rice systems. The research conducted herein covers various aspects of herbicide characterization including: barnyardgrass dose response, accession testing, spectrum of control and tank-mix capability, application optimization, soil carryover and plant back determination, drift onto …

Evaluation Of The Correlation Between The Oxidation Reduction Potential And Free Chlorine Residual For Different Chlorine Sources Used In Poultry Drinking Water Sanitation, Samantha Renee Cox

Graduate Theses and Dissertations

A critical component in commercial poultry production is to ensure birds are provided clean, quality water. Multiple disinfectants can be utilized to optimize a good water quality program. The goal of these water disinfectants is to greatly reduce or eliminate the presence of all bacteria. In recent years, the oxidation-reduction potential (ORP) meter has been a tool utilized by the poultry industry to monitor chlorine efficacy in drinking water. An ORP reading of 650-750 millivolts (mV) has become the industry standard for assuring an acceptable sanitizing residual of free chlorine is present for controlling microbial contamination regardless of the actual …

Evaluation Of Benzobicyclon For Use In Midsouthern Rice (Oryza Sativa) Systems, Mason Luke Young

Graduate Theses and Dissertations

A new herbicide site of action (SOA) is needed by rice (Oryza sativa L.) producers in the Midsouth for the control of problematic and herbicide-resistant weeds. Currently, six problematic weeds are relevant to Midsouthern rice producers because of resistance to at least one SOA, if not more. Gowan Company is in the process of commercializing benzobicyclon for use in Midsouthern rice systems. Benzobicyclon, a Group 27 post-flood herbicide, controls a broad spectrum of aquatics, broadleaves, grasses, and sedges, including those currently resistant to Group 2 herbicides. This will be the first 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide commercially available in US rice …

Dissecting Salt Tolerance In Soybean By Profiling Differential Physiological Responses Under Salt Stress, Jade Amber Newsome

Graduate Theses and Dissertations

Saline soils are common worldwide and limit the yield potential of many crops. Plants respond in a variety of ways to the stress imposed by saline soils. Plants under salt stress must first sense their surroundings and transmit a signal alerting the rest of the plant to the saline conditions. Salt tolerance in soybeans is typically defined by exclusion of chloride ions from foliar tissues. Though differences in ion uptake among soybean genotypes is well documented, the key mechanisms employed by tolerant cultivars to cope with salt stress on the whole-plant level are still largely unknown. Objectives of the current …

The Etiology, Virulence, And Phylogenetics Of The Celery Anthracnose Pathogen, Colletotrichum Fioriniae (= C. Acutatum Sensu Lato), Jason Alexander Pavel

Graduate Theses and Dissertations

An anthracnose disease of celery, caused by Colletotrichum acutatum sensu lato, has been reported in the U.S. A phylogenetic analysis was conducted on a collection of isolates from celery and non-celery hosts to evaluate their taxonomic position within Colletotrichum acutatum sensu lato. Both celery and non-celery isolates were evaluated for pathogenicity on celery and for vegetative compatibility. Culture filtrates from celery and non-celery isolates were evaluated for their ability to reproduce the unusual leaf curl type symptoms. A total of 18 celery isolates were evaluated for their taxonomic placement based on analysis of the glutamine synthetase intron sequence. All isolates …

Association Mapping Of Seed Weight, Protein, And Sucrose Content; And Kinetics Of Edamame Under Infrared Treatment, Laura Melissa Lara Santisteban

Graduate Theses and Dissertations

Edamame is a specialty large-seeded soybean (Glycine max L. Merr.) harvested at an immature stage (R6) that has become the second largest consumed soyfood. Although United States is the largest soybean producer, majority of edamame is imported from Asia, highlighting the importance of developing new edamame varieties. Association mapping (AM) provides an alternative to bi-parental linkage mapping method to detect quantitative trait loci (QTL) adding higher resolution and broader germplasm information. Seed weight, sucrose, and protein are quantitative traits of value when selecting edamame lines. However molecular mechanisms controlling each of these traits are still inconclusive and have not been …

Willingness To Pay For Irrigation Water Under Scarcity Conditions, Tyler Robert Knapp

Graduate Theses and Dissertations

Reliance of Arkansas agricultural producers on groundwater for irrigation has led to depletion of the Mississippi River Valley alluvial aquifer. Without intervention, consequences include insufficient groundwater to meet irrigation demand as well as drawdown of the deeper Sparta Aquifer, upon which communities in eastern Arkansas rely for non-agricultural use. Among proposed solutions to combat groundwater decline is the construction of off-farm surface water infrastructure to meet the irrigation needs of producers. Despite the importance of irrigated agriculture to Arkansas, there is little know about the economic value of irrigation water to producers. Thus, we implement a double-bounded dichotomous choice contingent …