Digital Commons Network^™

Developing Algorithms For Quantifying The Super Resolution Microscopic Data: Applications To The Quantification Of Protein-Reorganization In Bacteria Responding To Treatment By Silver Ions, Sai Divya Challapalli

Graduate Theses and Dissertations

Histone-like nucleoid structuring proteins (HNS) play significant roles in shaping the chromosomal DNA, regulation of transcriptional networks in microbes, as well as bacterial responses to environmental changes such as temperature fluctuations. In this work, the intracellular organization of HNS proteins in E. coli bacteria was investigated utilizing super-resolution fluorescence microscopy, which surpasses conventional microscopy by 10–20 fold in spatial resolution. More importantly, the changes of the spatial distribution of HNS proteins in E. coli, by addition of silver ions into the growth medium were explored. To quantify the spatial distribution of HNS in bacteria and its changes, an automatic method …

Seasonality And Management Of Spotted Wing Drosophila On Berry Crops And Wild Hosts In Arkansas, Lizabeth Rubi Herrera

Graduate Theses and Dissertations

Spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) is a serious invasive pest of small fruit production in North and South America and Europe since 2008. The primary control method is to apply insecticides every 5-7 days. Therefore, it is necessary to develop control tactics that are less chemical dependent to enhance an integrated approach for SWD management. The objectives of this study were to monitor SWD populations in different crop systems and adjacent landscape habitats; identify wild hosts of SWD; evaluate the effectiveness of insect exclusion netting in tunnels to prevent blackberry and blueberry infestations, and compare effects of netted …

Transcriptome-Based Gene Networks For Systems-Level Analysis Of Plant Gene Functions, Chirag Gupta

Graduate Theses and Dissertations

Present day genomic technologies are evolving at an unprecedented rate, allowing interrogation of

cellular activities with increasing breadth and depth. However, we know very little about how the

genome functions and what the identified genes do. The lack of functional annotations of genes

greatly limits the post-analytical interpretation of new high throughput genomic datasets. For plant

biologists, the problem is much severe. Less than 50% of all the identified genes in the model plant

Arabidopsis thaliana, and only about 20% of all genes in the crop model Oryza sativa have some

aspects of their functions assigned. Therefore, there is an …

Fall Risk In Sedentary, Recreationally Active, And Masters Athlete Older Adults, Felicia Elizabeth Squires

Graduate Theses and Dissertations

The purpose of this study was to examine whether different habitual activity levels may affect balance ability in older adults. Balance must be studied as poor balance increases likelihood of falls. This study examined activity levels in older adults and effect on balance ability. Fifty-nine older adults aged 66.5 ± 9.5 participated. Three groups were separated by physical activity level. First group had 13 masters athletes, older adults performing least 150 minutes of aerobic activity a week and competing in nationally sanctioned event within the last six months. Twenty-seven older adults comprised recreationally active group performing at least 150 minutes …

Understanding Intracellular Redox Regulation In Methanogens: Characterization Of The Components And Targets Of The Nadph-Dependent Thioredoxin System From Methanosarcina Acetivorans, Addison Clark Mccarver

Graduate Theses and Dissertations

All cells have a reduced intracellular environment. In the presence of oxygen, the non-specific oxidation of intracellular components leads to the production of reactive oxygen species (ROS) within cells leading to oxidative stress. During oxidative stress labile cofactors (e.g. Fe-S clusters) are lost and deleterious disulfide bonds are formed within proteins. Intracellular redox maintenance systems are used to direct reducing equivalents towards the repair of oxidatively-damaged proteins. The thioredoxin system is the ubiquitous intracellular redox system, found in virtually all species. The canonical thioredoxin system is comprised of a NADPH-dependent thioredoxin reductase (TrxR) that functions to reduced thioredoxin (Trx). Although …

Our Land Is Not Just Soil: Knowing, Feeling, And Doing Environmental Activism In The Arkansas Ozarks, Ramey Arlen Moore

Graduate Theses and Dissertations

The Ozarks is a holey place, an ancient plateau formed from ancient rocks and the sediment of millions of years of living things. The Ozarks is also, from another perspective a place made from a mesh of overlapping lines, lines of migration, lines of living things, lines of water movement over and through the land. This dissertation engages with the practice of conservation and environmentalism as it is performed and lived by Ozarkers and Arkansawyers, natives and transplants. Based on more than a year of ethnographic fieldwork conducted with the Buffalo River Watershed Alliance, Save the Ozarks, Arkansas Master Naturalists, …

Cellular Mechanisms Of Ionoregulation In The Gill Of Japanese Medaka And Rainbow Trout, Rebecca Jo Bollinger

Graduate Theses and Dissertations

Euryhaline fishes are capable of adapting to a wide range of salinities such as freshwater, brackish water or seawater. Through the combined effort of the gill, kidney and intestine, they are able to osmoregulate to maintain a constant internal hydromineral balance. As the gill is in direct contact with the external environment, it is continuously working to maintain ion and acid/base balance, gas exchange and eliminate nitrogenous waste. Fish in freshwater are subjected to osmotic water gain and diffusional ion loss across the gill and experience the opposite in seawater. Therefore, the gill exhibits extreme plasticity when experiencing a change …

The Cold War In The Eastern Mediterranean: An Interpretive Global History, James M. Brown

Graduate Theses and Dissertations

This thesis offers the first global history of the Cold War in the eastern Mediterranean. It examines the international linkages that bound Greece, Turkey, and Cyprus with superpowers, non-aligned states, and transnational movements during the second half of the twentieth century, and it considers the effects of such linkages upon the eastern Mediterranean’s domestic arenas. Throughout, it demonstrates that two forces – synthesis of outside influence alongside consolidation of internal identities – dictated the region’s experiences during the Cold War. And though the international environment furnished the conditions within which the region’s societies pursued the project of nation-building, indigenous forces …

Population Dynamics Of Ouachita Dusky Salamanders (Desmognathus Brimleyorum) In A Managed Forest Landscape, Kelly Marie Halloran

Graduate Theses and Dissertations

With anthropogenic alteration of landscapes increasing world-wide, managed forests are increasingly important as providers of ecosystem services including habitat for numerous wildlife species. It is crucial to maintain a balance between timber production and conservation of biodiversity on managed landscapes. Salamander populations can play key roles in the function and diversity of temperate forest ecosystems. Several studies have reported negative effects of forestry on terrestrial plethodontid salamanders, but less research has focused on stream-dwelling species, evaluated mechanisms driving observed shifts in abundance, or described the dynamics of populations residing in managed forests. Using a Before-After-Control-Impact design, we examined the effects …

Peptoid-Modified Bicelles As Surrogate Cell Membranes For Membrane Protein Sensors And Analytics, Helya Najafi

Graduate Theses and Dissertations

Membrane-affiliated interactions are significant in understanding cell function, detecting biomarkers to diagnose disease, and in testing the efficiency of new therapeutic targets. Model membrane systems have been developed to study membrane proteins, allowing for stable protein structure and maintaining native activity. Bicelles, disc-shaped lipid bilayers created by combining long- and short-chain phospholipids, are the model membrane system of focus in this study. Bicelles are accessible from both sides and have a wide size range, which make them attractive for studying membrane proteins without affecting function. In this work, bicelles were functionalized with two peptoids to alter the edge and face …

A Comparative Life Cycle Assessment Of Nutritionally Equivalent Meals With And Without Pork, Kelli Young

Graduate Theses and Dissertations

The following report details a life cycle assessment of several dietary and meal scenarios with and without pork. The goal of the LCA was to identify the impacts of greenhouse gas emissions, water use, and land use of pork containing and porkless diets and meal plans in a field-to-fork analysis. The dietary and meal plan scenarios are iso-caloric meaning they contain the same number of calories. The first set of diets is based on a USDA consumption pattern, 2000 kcal per day. This diet was used to create three other dietary scenarios with and without pork. The USDA recommended food …

Characterization And Mechanisms Of Anthocyanin Degradation And Stabilization, Nathan Blaine Stebbins

Graduate Theses and Dissertations

Anthocyanins (ACYs) are polyphenol compounds found in nature, which contribute vivid colors to many fruits and vegetables, while also possessing significant health benefits. These pigments range in color from orange-red to blue-violet and could serve as natural colorants to replace artificial additives. There is a great demand from consumers to have fewer artificial compounds in their foods. However, the relatively instability of ACYs must be further understood in order to limit color degradation before they can completely replace synthetic colorants.

ACYs slowly degrade over time, but there is a knowledge gap on their fate and mechanisms causing degradation. In order …

Methodologies For Solving Integrated Transportation And Scheduling Problems, Fereydoun Adbesh

Graduate Theses and Dissertations

This research proposes novel solution techniques to optimize two real-world problems in the area of scheduling and transportation. We first consider a model for optimizing the operations of dredges. In this problem, scheduling and assignment decisions are integrated across a finite planning horizon. Additional constraints and problem elements explicitly considered include, but are not limited, to environmental work window restrictions, budget limitations, dredge operation rates and schedule-dependent dredge availability. Our approach makes use of Constraint Programming (CP) to obtain quality and robust solutions within an amount of time small enough to be useful to practitioners. The expanded feature set of …

Economic And Policy Evaluations And Impacts Of The National Rice Development Policy Strategies In Malaysia: Self-Sufficiency, International Trade, And Food Security, Roslina Binti Ali

Graduate Theses and Dissertations

Despite the fact that the recent rice policy has been moving to a strategy of self-sufficiency while the status quo of the national rice economy remains ambiguous, Malaysia has made an extreme policy decision to pursue an autarky economy in its rice sector, thus closing borders from the international markets in the future. The goal of this dissertation research is to comprehensively evaluate a deep-rooted rice policy in Malaysia and analyze the holistic impacts of the self-sufficiency and international trade policies at the national and farm-household levels, utilizing economic frameworks. The protectionist policy measures using a Policy Analysis Matrix reveals …

Evaluation Of Provisia Rice In Arkansas Rice Production Systems, Zachary Lancaster

Graduate Theses and Dissertations

With the continued evolution of herbicide resistance, it is becoming more difficult to achieve adequate weed control in Arkansas rice production systems. Thus, new technologies are needed to combat these troublesome weeds. A new non-GMO, herbicide-resistant rice type is under development that is resistant to quizalofop, an acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicide that will allow for selective grass weed control in rice. With the commercialization of this technology by 2018, research was conducted to determine the best fit for quizalofop-resistant rice in current production systems. Experiments included evaluation of off-target movement of quizalofop, determination of plant-back risk from quizalofop …

Evaluation Of Very-Long-Chain Fatty Acid-Inhibiting Herbicides In Arkansas Rice Production, John Ansley Godwin

Graduate Theses and Dissertations

Because of the evolution of herbicide-resistant weeds, such as barnyardgrass and red rice in rice, there is a need for alternative herbicide sites of action. Very-long-chain fatty acid (VLCFA)-inhibiting herbicides are not labeled for use in U.S. rice production; however, this site of action (SOA) has been used with success in Asian rice. The VLCFA-inhibiting herbicides pethoxamid, pyroxasulfone, acetochlor, and S-metolachlor were evaluated for rice tolerance and control of commonly problematic weeds in Arkansas rice at various rates and application timings. Pyroxasulfone and S-metolachlor were deemed unfit for use in rice production because of negative effects on rice visual injury, …

Effect Of Endophyte-Infected Tall Fescue Toxins On Growth Performance And The Microbial Community In The Rumen And Feces In Pregnant Ewes, Saleh Alrashedi

Graduate Theses and Dissertations

Fifty pregnant Katahdin ewes grazed pastures with high (HE) and moderate (MI) levels of Neotyphodium coenophialum-infected tall fescue between February 1 and May 24 to determine the impacts of tall fescue toxins on body weight (BW), body condition scores, FAMACHA scores, fecal egg counts (FEC), and serum Cu, Zn, prolactin, and non-esterified fatty acids (NEFA). Within those 50 ewes, 15 were selected randomly for fecal and rumen sampling to assess the impacts of HE and MI on the microbiome community. Total bacterial DNA was extracted from rumen and fecal samples, and alpha and beta diversities were used to relate microbiome …

Green Chemistry Oxidative Modification Of Peptoids Utilizing Bleach And Tempo, Jesse Leland Roberts

Graduate Theses and Dissertations

Biotherapeutic drugs, derived from biological molecules such as proteins and DNA, are becoming an integral and exceptionally critical aspect of modern medicine. Compared to common pharmaceutical drugs, biotherapeutics are much larger in size and have greater target specificity, allowing them to treat many chronic diseases ranging from cancer to rheumatoid arthritis. The major issue with protein based therapeutics is that they readily undergo proteolysis, or enzymatic degradation, when administered through subcutaneous injections. Traditionally, biotherapeutic modification procedures have centered on the use of PEG derivatives. This process, called PEGylation, is unfavorable due to the increases in molecular weights of the proteins …

Determination Of The Effects Of Different Maillard Reaction Products On The Taxonomic Composition Of The Gut Microbiota, Nesreen Hamdan Aljahdali

Graduate Theses and Dissertations

The Maillard Reaction (MR) is a non-enzymatic chemical reaction which results in linkage between the amino group of amino acids and the carbonyl group of reduced sugars. This reaction generates Maillard reaction products (MRPs) which are not present naturally in foods, and are responsible for a range of colors, odors, flavors, and other sensory properties. Conflicting reports of MRPs impacts on human health are probably due to the fact that bioconversion of these digestible molecules by the gut microbiota has been marginally taken into account. This study aimed to determine the effects of different MRPs on rodent’s gut microbiota through16S …

Characterization Of Multiple-Herbicide-Resistant Echinochloa Colona From Arkansas, Christopher Edward Rouse

Graduate Theses and Dissertations

Echinochloa species are highly adaptive weeds that have the potential to impact crops in a variety of environments. This has positioned them as the most problematic weeds in a number of USA cropping systems with some species having the distinction of the 'worst herbicide-resistant weeds' in the world. Recent evidence has positioned Echinochloa colona (junglerice) as the most dominant in Arkansas and throughout the Mid-South, USA, especially in rice (Oryza sativa L.) and soybean (Glycine max L.) production fields. A history of extensive herbicide-use for management and a lack of integrated or diverse approaches to management have led to rampant …

The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond

Graduate Theses and Dissertations

Urea-N fertilizer is typically applied at the 5-leaf stage to rice (Oryza sativa L.) grown in a dry-seeded, delayed-flood production system. How long the preflood-N can be delayed without adverse effects on yield potential is poorly understood. The research objective was to determine the effects of preflood-N application and flood establishment timing on aboveground-N content, 50% heading, yield components, and grain yield. Trials were established on silt loam soils at the Pine Tree Research Station (PTRS) and Rice Research and Extension Center (RREC) during 2015 and 2016. Urea-N was applied at 0, 45, 90, 135, and 180 kg N ha-1 …

Detection Of Survival And Proliferation Of Sulfate Reducers Under Simulated Martian Atmospheric And Soil Conditions, Sergio Mosquera Mora

Graduate Theses and Dissertations

Numerous studies have tried to determine the survivability and proliferation of microorganisms under simulated Martian conditions. Furthermore, most of them have been focused on the ability of these microbes to cope with high brines’ salt (NaCl) concentrations inherent of the Martian surface. However, there are not studies related to the ability of bacteria to survive on subsurface environments that have increasing concentrations of sulfate compounds. For this research, a group of microorganisms known as sulfate-reducing bacteria or simply sulfate reducers were chosen due to their ability to use sulfate compounds as terminal electron acceptors to produce metabolic energy, their tolerance …

Literary And Cinematic Representations Of Neoliberal Forms Of Contemporary Violence In Latin America With Special Interest In Mexico And Colombia, Ivan De Jesus Iglesias

Graduate Theses and Dissertations

In the last decades, with an increased rhythm and greater intensity, the so-called neoliberal violence has come to play a relevant role within the history of world societies. The Latin American institutional, political, social, and economic changes of the 1970’s and 1980’s, especially those produced under dictatorships, contributed to create the conditions for the implementation of the processes of economic liberalization and global market as part of the concept of institutional modernization and cultural globalization that gave rise to the neoliberal mentality. In this context, neoliberalism becomes hegemonic as a mode of discourse and is incorporated into the way individuals …

Characterization Of Glyphosate-Resistant Amaranthus Palmeri (Palmer Amaranth) Tolerance To Als- And Hppd-Inhibiting Herbicides, Shilpa Singh

Graduate Theses and Dissertations

Palmer amaranth is a principal weed problem across the United States and is resistant to several herbicide modes of action. By 2008, Palmer amaranth in Arkansas was reported to be resistant to both ALS- and EPSPS-inhibitors, but the predominant resistance mechanisms are yet to be explored. Herbicide options with different modes of action are needed to provide effective Palmer amaranth control and HPPD-inhibitors (e.g. mesotrione) are among these. The goal of this research was to elucidate the resistance profile of Palmer amaranth in Arkansas to ALS herbicides and glyphosate (EPSPS-inhibitor) as well as evaluate the differential tolerance of Palmer amaranth …

Piglet Gut Microbiota Responses To Exposure To Outdoor Simulated Environment And Formula Feeding, Nguyen Vo

Graduate Theses and Dissertations

Several lines of evidence suggest that early-life gut microbiota composition is a crucial determinant of the susceptibility to diseases later in life. Understanding the evolution of early-life gut microbiota and critical factors that can modify this microbial community will espouse the prevention or reversion of health risk originating from dysbiosis of the gut microbiota in the early stage. In this research, we hypothesized that alterations in the environment (simulation of rural conditions by soil exposure) and feeding mode (breastmilk versus formula milk) will have significant impacts on the establishment of the gut microbiota in early life. At first, in literature …

The Economic Benefits Of The South African Agricultural Research Council’S Wheat Breeding Program: 1992–2015, Matthew James Coale

Graduate Theses and Dissertations

Although classified as an upper middle-income country by the World Bank, food insecurity is still a concern throughout South Africa, as was evident in 2014–2015 when a drought left 22% of households food insecure. As such, agricultural research in South Africa is needed specifically in plant breeding to increase yields and help mitigate future food insecurity. To fill this need, the South African government funds the Agricultural Research Council (ARC), which conducts holistic research on wheat and other crops. Wheat is important to South African food security; due to the significant drop in wheat area planted since the abolishment of …

Role Of Incompatibility Group 1 (Inci1) Plasmid-Encoded Factors On Salmonella Enterica Antimicrobial Resistance And Virulence, Pravin Raghunath Kaldhone

Graduate Theses and Dissertations

Foodborne illnesses are a leading cause of infectious diseases in the world. Among enteric organisms Salmonella is a key pathogen. It’s high prevalence in poultry and other food-animal sources make it imperative to study. Salmonella has the ability to modify its genetic content with help of mobile genetic elements such as plasmids. Incompatibiltiy group 1 (IncI1) plasmids are commonly reported in Salmonella. This study evaluates role on IncI1 plasmids in antimicrobial resistance and virulence in Salmonella. Genetic determinants of resistance and virulence are noted among our IncI1-containing Salmonella isolates. These genetic elements are also transferable and reported to carry respective …

Exploring The Empirical Relationship Between Civic Agriculture And Community Resilience, Beth Joanna Person-Michener

Graduate Theses and Dissertations

Smaller-scale, qualitative and mixed method studies indicate that civic agriculture generates positive, local-level social change, specifically by increasing social, human and economic capital. These social benefits are also identified as some of the crucial components needed for community resilience to disasters. However, literature directly linking civic agriculture to community resilience is sparse and there is little if any research explicitly examining a relationship between civic agriculture and community resilience. This study lends national scope and an empirical examination of evidence for a positive relationship between civic agriculture and community resilience along the applicable domains of social, human and economic capital …

A Comparative Analysis Of Feed And Environmental Factors On Broiler Growth In The United States, Alexandra Gulli

Graduate Theses and Dissertations

Broiler production in the United States has become an important industry within the last half century. As the demand for poultry continues to increase and the concern of climate change also increases, it will become an important part of the industry to become more sustainable. This study uses a feed optimization model, a broiler growth model, and a life cycle assessment (LCA) to determine how feed ingredients and the barn environment can affect the broiler’s growth and production emissions. A multi-criteria ration optimization model is used to produce feeds based on carbon footprint and cost. A growth model is used …

Evaluating Thermal Comfort Of Broiler Chickens During Transportation Using Heat Index And Simulated Electronic Chickens, Kaushik Luthra

Graduate Theses and Dissertations

Broilers experience high physiological stress during pre-slaughter transport, especially under extremes of thermal environment. Characterization of thermal environment on the trailer is crucial to identify stress-prone regions during transportation. At the same time, Broilers experience high physiological stress during pre-slaughter transport, especially under extremes of thermal environment. Characterization of thermal environment on the trailer is crucial to identify stress-prone regions during transportation. At the same time, quantification of heat loss of the broilers loaded on trailers is important in understanding the well-being of the broilers. We have developed four electronic chickens (E-chickens) to simulate the sensible heat loss of live …