Digital Commons Network^™

Development Of A Multiband Remote Sensing System For Determination Of Unsaturated Soil Properties, Cyrus D. Garner

Graduate Theses and Dissertations

A multiband system including active microwave sensing and visible-near infrared reflectance spectroscopy was developed to measure unsaturated soil properties in both field and laboratory environments. Remote measurements of soil volumetric water content (θv), soil water matric potential (ψ), and soil index properties (liquid limit [LL], plastic limit [PL], and clay fraction [CF]) were conducted. Field-based measurement of θv was conducted using a ground-based radar system and field measurements within 10 percentage points of measurements acquired with traditional sampling techniques were obtained. Laboratory-based, visible and near infrared spectroscopy was found to be capable of obtaining empirical, soil specific regression functions (partial …

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 …

Refusing To Be Dispossessed: African American Land Retention In The Us South From Reconstruction To World War Ii, Camille Goldmon

Graduate Theses and Dissertations

African Americans in the South were tied to the land during slavery and after emancipation. Many felt that land ownership was the key to freedom. For decades, black farmers strove for land ownership, in many cases falling prey to sharecropping and tenancy agreements in the meantime. Despite this drive toward independent farming, however, since 1920, there has been a steady decline in the number of black farm owners. This trend is especially prevalent in the Southern United States. The black farm owners who persevered through periods of economic, social, and political turmoil were able to, for varying reasons, navigate those …

Environmental And Climatic Constraints On Large-Scale Camelina Production In Eastern Arkansas, Benjamin Robert Tracy

Graduate Theses and Dissertations

Camelina sativa is a cold weather crop that is typically grown in semi-arid environments in the Western United States, usually as a spring crop, but sometimes during the winter. Research analyzing climate data and soil hydrology is important to better understand the environmental and terrain conditions necessary for Camelina farming wherever it is proposed for large-scale production. This study focused on various conditions and constraints pertaining to the potential for Camelina as a crop biofuel in Eastern Arkansas. Due to interest in the economic potential of crop biofuels in this area, and in particular the low input costs for Camelina, …

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 …

Influence Of Histidine Residues, Ph And Charge Interactions On Membrane-Spanning Peptides, Ashley N. Henderson

Graduate Theses and Dissertations

Designed transmembrane peptides were employed for investigations of histidine residues within the hydrophobic environment of the lipid bilayer by means of oriented solid-state deuterium NMR spectroscopy. Using the model peptide GWALP23 sequence (GGALW(LA)6LWLAGA) as a host framework, the effects of single and double histidine mutations were explored. Replacement of leucine residue 12 to polar neutral histidine had little influence on the peptide average orientation, however under strongly acidic pH conditions in DOPC bilayers, the histidine becomes positively charged (pKa 2.5) and the GWALP23-H12 peptide exits the membrane and adopts a surface-bound orientation. Conversely, mutation of leucine 14 to neutral histidine …

Temporal Evaluation Of Corn Respiration Rates Using Pressure Sensors, Gagandeep Singh Ubhi

Graduate Theses and Dissertations

High respiration rate of a grain indicates faster degradation of its dry matter. Proper grain management requires chronological and precise measurements of carbon dioxide evolved from grain respiration during the postharvest storage duration. Therefore the main goal of this research was to develop a new technique that evaluates temporal corn respiration rate using pressure sensors. It was based on measuring pressure drop associated with the grain respiration in a closed container and using it to calculate the grain respiration rates.

Dry corn (Zea Mays L.) was procured from a local farmer and stored at 4ºC. Corn rewetting technique was applied …

Influence Of Stream Permanence, Predation, And Invasive Species On Crayfish In The Ozark Highlands With An Emphasis On Species Of Greatest Conservation Need (Orconectes Marchandi, Orconectes Eupunctus And Cambarus Hubbsi), Allyson Noelle Yarra

Graduate Theses and Dissertations

Due to the ecological importance of crayfish and the increasing vulnerability of freshwater systems due to habitat loss, invasive species, and hydrologic alteration, understanding crayfish-environment relationships is crucial in the context of aquatic species conservation. I sought to examine the influence of hydrologic variation among intermittent and permanent streams on crayfish occupancy, abundance, predation risk, and potential vulnerability to invasive species effects. I conducted crayfish and environmental data sampling during two consecutive summers across 20 Ozark streams of differing permanence levels (10 intermittent, 10 permanent). In these same streams, I conducted fish and scat surveys over the course of four …

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 …

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 …

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 …

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 …

Development Of A One Pass Microwave Heating Technology For Rice Drying And Decontamination, Deandrae Lynette Smith

Graduate Theses and Dissertations

An industrial microwave (MW) system operating at 915 MHz frequency was used to dry high moisture content (MC) (23% to 24% wet basis) medium-grain rough rice samples (cv. Jupiter). The rice beds were contained in a modified tray that accommodated up to 9 kg of rice separated by thin fiberglass mesh in 3 kg increments. Each layer of rice was fitted with fiber optic sensors connected to a real time data logger during MW treatments. It was determined that drying rice to a MC of 14% to 16% was feasible with the application of MW specific energy at 600 kJ/kg-grain …

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 …

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 …

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 …

Identification Of Molecular Signatures Of Environmental And Nutritional Stress Responses In Poultry, Phuong Hieu Nguyen

Graduate Theses and Dissertations

Poultry production plays an important role in the food supply and security for billions of people. Poultry meat is considered the most efficient, nutritious source of protein, without religious taboos, and is relatively inexpensive. However, the poultry industry is facing substantial challenges. The global environmental temperature has experienced dramatic changes in the last few years. Modern broilers are not well adapted to environmental challenges (heat and cold stress), which have resulted in heavy economic loss in the poultry industry worldwide. In addition, the use of feed restriction regimens in management of breeders as well as the transportation of young chicks …

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 …

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 …

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 Safening Effects To Herbicides Conferred Via Insecticide Seed Treatments In Soybean (Glycine Max) And Grain Sorghum (Sorghum Bicolor), Nicholas Robert Steppig

Graduate Theses and Dissertations

Interactions between herbicides and insecticides in crop production have been documented for a number of years. Research has shown that applications of some organophosphate insecticides at planting can reduce cotton injury following applications of the soil-applied herbicide clomazone. Additionally, recent research has shown that, when applied as seed treatments prior to planting, some neonicotinoid insecticides can safen rice to drift from both glyphosate and imazethapyr. Since insecticide seed treatments are commonly used in many crop production systems throughout the Midsouth, exploring their ability to reduce injury from herbicides in other crops besides rice is of great interest. Presently no research …

Phenology, Habitat Use, And The Impacts Of Wetland Management On Autumn Migrating Rails In Missouri, Auriel M.V. Fournier

Graduate Theses and Dissertations

Rails (Family: Rallidae) are among the least studied birds in North America, in large part due to their elusive nature. As a wetland-dependent species, understanding the timing of their migration and their habitat needs during migration is especially important since management needs to be timed to balance the needs of many species. I developed and verified a new distance sampling based nocturnal ATV spotlight survey because traditional call-broadcast surveys are not effective during autumn migration because of the drop off in call rate after the breeding season. These surveys allow us to ask point-level questions about what habitats rails select …