Life Sciences Commons^™

Role Of Meibum And Tear Phospholipids In The Evaporative Water Loss Associated With Dry Eye., Samiyyah M. Sledge

Electronic Theses and Dissertations

It is generally believed that the tear film lipid surface film inhibits the rate of evaporation (Revap) of the underlying tear aqueous. It is also generally believed that changes in the composition of the tear film lipid layer is responsible for an increase in Revap in patients with dry eye. Both of these ideas have never been proven. The purpose of the current studies was to test these ideas. Revap was measured in vitro gravimetrically. Lipid spreading was measured using Raman spectroscopy and microscopy. The influence of the following surface films on the Revap of the sub phase of physiologically …

How Do Cover Crops Change Soil Health In A No-Till System?, Aysha Kirsten Tapp Ross

Electronic Theses and Dissertations

Nutrient levels and aggregation measurements are currently the most accurate means to measure soil health. It has been suggested that bacterial and fungal communities may prove to be a more accurate measure of soil health. In this study soil microbe communities and nutrient levels were compared in rye cover cropped soils to measure for differences between treatments. Effects between the microbial communities and environmental measurements were also measured within those treatments to test for correlations between soil health measures and microbial communities. The plots were put in a biennial corn (Zea mays L.) and soybean (Glycine max …

New Titanate Bioceramic Nanomaterials For Drug Delivery And Controlled Release, Seaab Imad Sahib

Graduate Theses and Dissertations

Nanomaterials have attracted much attention for biomedical applications due to their unique characteristics that are proven to be potential in cell sensing, drug delivery, biological membrane penetration, biocompatibility, and tissue adhesion. The outcomes of this dissertation presented in chapter III-V mainly discuss new approaches in drug delivery, cellular uptake improvement, and neuronal regeneration and protection using a well-optimized titanium-based nanomaterial. In particular, Chapter III summarizes the impact of two different versions of the titanate nanowires on ameliorating the delivery of the antimicrobial and anticancer drug in vitro. Those drugs were loaded on the surface of the fabricated nanowires and characterized …

Economic Potash Fertilizer Rate Recommendations, Kimberly B. Oliver

Graduate Theses and Dissertations

This thesis is comprised of two studies that estimate profit-maximizing potassium (K) fertilizer application rates for various crops across different time periods. Estimation of profit-maximizing fertilizer-K rate (K*) for both studies considered the initial soil test level of K (STK) and yield response information, as traditional recommendations do, and added crop price and the cost of fertilizer. Profit maximum occurs where the marginal revenue from additional yield is equal to the marginal cost of applying an additional unit of fertilizer-K. The first study calculated K* for corn (Zea mays) and cotton (Gossypium hirsutum) and compared results to previous studies on …

Impact Of Planting Arrangement And Drill Row Spacing For Direct-Seeded, Delayed Flood Rice, Mary Jane Lytle

Graduate Theses and Dissertations

Direct-seeding is the most frequently utilized planting practice in Arkansas and Mid-South rice (Oryza sativa L.) production. Enhanced plant density and more rapid rice canopy formation may result from the implementation of innovative plant arrangements and spacings. Studies were initiated in 2019 and continued into 2020 to examine different cultural management practice experiments, including evaluating the impacts of planting arrangement, row spacing, and seeding rates on rice stand density, canopy coverage, grain yield, and milling yield. These small-plot trials were conducted at two locations, a silt loam site and a clay site, representative of soils produced to rice in eastern …

Mitigating Rice Injury Caused By Florpyrauxifen-Benzyl And Optimizing Florpyrauxifen-Benzyl Rate And Timing For Use In Furrow-Irrigated Rice, James Winston Beesinger

Graduate Theses and Dissertations

Florpyrauxifen-benzyl (synthetic auxin, WSSA Group 4) is a postemergence, broad-spectrum herbicide labeled for use in Mid-South rice (Oryza sativa L.) production. Introduction of florpyrauxifen-benzyl to Arkansas rice production led to observations of varying levels of injury caused by the herbicide across cultivars and environments. Findings from previous research indicated hybrid long-grain rice and medium-grain rice were more susceptible to florpyrauxifen-benzyl and hypotheses were formed using this research regarding the impact of environmental conditions on the amount of injury observed. Concerns of yield loss, delay in maturity and loss of groundcover as well as questions regarding the ability of florpyrauxifen-benzyl to …

Divergent Selection For Water Conversion Ratio In Broiler Populations, Joseph Hiltz

Graduate Theses and Dissertations

Water scarcity is a global reality and with the anticipated population growth, freshwater resources will be further strained to meet both human needs and agriculture applications. To ensure a water sustainable and food secure future, all aspects of agriculture must become more efficient. Two strategies were explored. The potential of improving water efficiency in broilers was examined. The first strategy was to develop a more efficient and accurate method for measuring water consumption/inputs in agriculture. To date, water measuring technology has lacked the necessary sophistication to assure accuracy and repeatability of low flow water usage.

After establishing a low flow …

Evaluation Of Two Neonatal Challenge Models For Broiler Chickens And Their Effects On Early Performance Parameters, Callie Selby

Graduate Theses and Dissertations

Formaldehyde fumigation in poultry hatch cabinets has been utilized for sanitation of hatching eggs for over a century. Formaldehyde is utilized to minimize pathogenic microbes on the surface of the egg as well as the microbial bloom during the hatching process. While formaldehyde is effective, its use is regulated in the United States and Europe due to its carcinogenic nature. Formaldehyde has been shown to damage the cuticle of the egg, cause embryonic death, and damage the epithelial lining of the respiratory tract of freshly hatched chicks, predisposing them for respiratory infection. Alternatives for formaldehyde fumigation must be identified and …

Investigating Effects Of Microenvironmental Stress On Cell Metabolism Using Multiphoton Imaging, Lisa Rebello

Graduate Theses and Dissertations

Resistance to therapy in cancer is a major cause of poor prognosis in patients. Tumor hypoxia plays an active role in mediating treatment resistance and has been linked to metastases and metastatic potential in cancer. Our research focused on three objectives: i) To understand metabolic effects of chronic and intermittent hypoxia in murine breast cancer cells and its affiliation with metastatic potential ii) To identify the metabolic changes associated with radiation therapy in a panel of radiosensitive and radioresistant human head and neck cancer cells and iii) to monitor the changes in cell metabolism associated with gain of treatment resistance. …

Dissonance Between Christian Beliefs And Eating Habits In The South, Karli Dianne Stringer

Graduate Theses and Dissertations

The purpose of this qualitative study was to initiate understanding of how obesity in the South is still so prevalent even though the majority of inhabitants subscribe to a faith that discourages unhealthy lifestyles. Furthermore, the information presented in this research sought to fill the knowledge gap for communicators and educators concerning the dissonance between Christianity in the South and the unhealthy eating habits of Southerners. Grounded in the Cognitive Dissonance Theory, this study comprised of a semi-structured interview route in which Protestant evangelical Christians in the South (N = 11) participated in a descriptive study conducted by a committee …

Genome-Wide Analyses Of Genomic Variation Regulating Differential Stress Responses In Japanese Quail, Steven Anthony Shumaker

Graduate Theses and Dissertations

As consumer demands for poultry grow, producers work to improve bird productivity in both meat and egg production. This endeavor is multifaceted, as many different factors play a part in influencing the productivity of birds, including environmental conditions, overall health, and genetic potential. One aspect controlled for in all aspects of poultry production optimization is stress management. Mitigation of stress is of primary concern to producers, as improper stress management can have many deleterious effects on chickens. Stress management requires an understanding of poultry stress responses and their physiological mechanisms, which can be more deeply understood through genomic analysis. Chapter …

Deciphering Chemomechanical Couplings In Proteins Using Microsecond-Level Molecular Dynamics Simulations, Vivek Govind Kumar

Graduate Theses and Dissertations

All-atom molecular dynamics (MD) simulations combine the high temporal resolution of experimental methods like smFRET and spatial resolution of methods like x-ray crystallography, to provide a detailed dynamic picture of biomolecular processes. Here, microsecond-level atomistic MD simulations have been used to characterize chemomechanical couplings in human fibroblast growth factor 1 (hFGF1) and the spike proteins of SARS CoV-1 and SARS-CoV-2. hFGF1 is a globular signaling protein that is involved in several physiological processes ranging from cell proliferation to wound healing. Experimental studies have previously described the low proteolytic and thermal stability of hFGF1, in addition to the stabilizing role of …

Precise Nitrogen Recommendations Improve Economic And Environmental Outcomes In Arkansas Rice Production, Cristin Roberts

Graduate Theses and Dissertations

Soil testing has become an increasingly important tool in making agronomically efficient production management decisions. N-STaR is a N test used in rice production and is unique in its ability to selectively quantify soil organic-N compounds which are readily mineralizable for plant N uptake and contribute to growth and yield. This study uses historical (2002–2018) adoption rates of N-STaR, which is funded through Rice Checkoff funds, to calculate the total cost savings from N-STaR adoption. These cost savings alone would be the “typical” benefits used in a benefit-cost ratio of a public ally funded research program like N-STaR. However, we …

The Dilemma Of Guinea Grass (Megathyrsus Maximus): A Valued Pasture Grass And A Highly Invasive Species, Aaron C. Rhodes, Robert M. Plowes, John A. Goolsby, John F. Gaskin, Boaz Musyoka, Paul André Calatayud, Massimo Cristofaro, Eric D. Grahmann, Dino J. Martins, Lawrence E. Gilbert

All Peer-Reviewed Publications

On a global scale, invasive grasses threaten biodiversity and ecosystem function. Nevertheless, the importation of forage grasses is a significant economic force driven by globalization. Pastureland and rangeland are of critical economic and ecological importance, but novel grass species may lead to invasion. Recognizing that economically important species can also be ecologically damaging creates a contentious debate for land managers, policymakers, and ecologists alike. Many Afrotropical perennial grass species have been intentionally introduced pantropically given their high forage production and resistance to stress. However, these traits may also confer competitive ability, increasing the possibility of unintended escape and invasion. Further, …

Root Exudate Chemical Cues Of An Invasive Plant Modulate Oviposition Behavior And Survivorship Of A Malaria Mosquito Vector, Trizah K. Milugo, David P. Tchouassi, Reginald A. Kavishe, Rhoel R. Dinglasan, Baldwyn Torto

All Peer-Reviewed Publications

Gravid female Anopheles gambiae mosquitoes identify suitable oviposition sites through a repertoire of cues, but the influence of allelochemicals, especially root phytochemicals in modulating this behavior and impacting subsequent progeny bionomics remains unexplored. We addressed these questions in the malaria vector Anopheles gambiae and its invasive host plant Parthenium hysterophorus. Using chemical analysis combined with laboratory behavioral assays, we demonstrate that a blend of terpenes, namely α-pinene, α-phellandrene, β-phellandrene, 3-carene and (E)-caryophyllene emitted from P. hysterophorus root exudate treated-water attracted gravid females. However, fewer eggs (55%) hatched in this treatment than in control water (66%). The sesquiterpene lactone parthenin, identified …

Toward Lignin Valorization: Development Of Rhodococcus Opacus Pd630 As A Chassis For Triacylglycerol (Tag) Production From Recalcitrant Aromatic Feedstocks, Rhiannon R. Carr

McKelvey School of Engineering Graduate Student Theses & Dissertations

The advent of the industrial era was precipitated by the discovery of fossil fuels, and ushered in unprecedented changes for humanity included but not limited to the development of rapid transit and communications, improvements to food distribution and preservation, the mass production of goods, and a radical rearrangement of communities from relatively small enclaves to metropolises. With all the benefits, however, come considerable costs, especially to the global environment. Greenhouse gas emissions, built up over centuries of unregulated combustion, have precipitated a rate of global temperature change unparalleled in the 4.5 billion-year history of this planet. In order to preserve …

Arkansas Soybean Research Studies 2020, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2020 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations. Several research reports in this publication will appear in other University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research …

Exploring The Role Of Ampk In Nutrient Sensing And Signaling In The Human Parasite Trypanosoma Brucei, Jessica Jones

All Dissertations

African trypanosomes are protozoan parasites that cause the diseases African sleeping sickness and nagana, in humans and cattle respectively. These parasites have complex life cycles with infection of a mammalian host, ~5mM glucose, following transmission by an insect vector, essentially zero glucose. With these pathogens being exposed to rapidly changing glucose abundance in a host-dependent manner, the ability to sense and rapidly respond to changes in the availability of the hexose are critical. First, I provide a review of glucose metabolism in Trypanosoma brucei. Then, we explore the role of the catalytic α subunit of AMPK, a eukaryotic master …

Northern Bobwhite Occupancy Patterns On Multiple Spatial Scales Across Arkansas, Ellery V. Lassiter, Marcus Asher, Grace Christie, Connor Gale, Andrhea Massey, Cody Massery, Christopher R. Middaugh, John T. Veon, Brett A. Degregorio

Biological Sciences Faculty Publications and Presentations

Northern bobwhite Colinus virginianus populations have been rapidly declining in the eastern, central, and southern United States for decades. Land use change and an incompatibility between northern bobwhite resource needs and human land use practices have driven declines. Here, we applied occupancy analyses on two spatial scales (state level and ecoregion level) to more than 5,000 northern bobwhite surveys conducted over 6 y across the entire state of Arkansas to explore patterns in occupancy and land use variables, and to identify priority areas for management and conservation. At the state level, northern bobwhite occupied 29% of sites and northern bobwhite …

Discerning The True Dilemma Of Diabetes Among Hispanics, Ramon Ponce

Nursing | Senior Theses

There is a common misconception that the primary role of nurses is to follow doctors’ orders and treat patients who are currently suffering and experiencing pain. Chronic illnesses such as diabetes can be prevented and better managed if the population who is greatest at risk is better informed and educated on the disease. Different cultures and ethnicities have different foods that unfortunately puts them at risk to get diabetes. Hispanics typically follow a diet that is high in carbohydrates, saturated fats, and sugars that greatly contribute to the development of diabetes. Often, Hispanics are not educated enough to comprehend the …

The Philosophy Of Outliers: Reintegrating Rare Events Into Biological Science, Chelsea N. Cook, Angela R. Freeman, James C. Liao, Lisa A. Mangiamele

Biological Sciences: Faculty Publications

Individual variation in morphology, physiology, and behavior has been a topic of great interest in the biological sciences.While scientists realize the importance of understanding diversity in individual phenotypes, historically the minority results (i.e., outlier observations or rare events) of any given experiment have been dismissed from further analysis. We need to reframe how we view outliers to improve our understanding of biology. These rare events are often treated as problematic or spurious, when they can be real rare events or individuals driving evolution in a population. It is our perspective that to understand what outliers can tell us in our …

Field Evaluation Of A New Third Generation Push-Pull Technology For Control Of Striga Weed, Stemborers, And Fall Armyworm In Western Kenya, Duncan Cheruiyot, Frank Chidawanyika, Charles A.O. Midega, Jimmy O. Pittchar, John A. Pickett, Zeyaur R. Khan

All Peer-Reviewed Publications

Production of cereal crops in sub-Saharan Africa is threatened by parasitic striga weeds and attack by stemborers and the invasive fall armyworm (FAW), compounded by increasing hot and dry conditions. A climate-smart push-pull technology (PPT) significantly reduces effects of these biotic challenges. To improve further resilience of the system to climate change, more adapted and suitable companion plants were identified and integrated in a new version of PPT, termed 'third generation PPT'. Our study evaluates field performance and farmer opinions of this new version in comparison with the earlier version, climate-smart PPT, and farmers' own practices of growing maize in …

Occurrence, Diversity And Distribution Of Trypanosoma Infections In Cattle Around The Akagera National Park, Rwanda, S. Richard Gashururu, Ndichu Maingi, Samuel M. Githigia, Methode N. Gasana, Peter O. Odhiambo, Dennis O. Getange, Richard Habimana, Giuliano Cecchi, Weining Zhao, James Gashumba, Joel L. Bargul, Daniel K. Masiga

All Peer-Reviewed Publications

Background African Trypanosomiases threaten the life of both humans and animals. Trypanosomes are transmitted by tsetse and other biting flies. In Rwanda, the African Animal Trypanosomiasis (AAT) endemic area is mainly around the tsetse-infested Akagera National Park (NP). The study aimed to identify Trypanosoma species circulating in cattle, their genetic diversity and distribution around the Akagera NP. Methodology A cross-sectional study was carried out in four districts, where 1,037 cattle blood samples were collected. The presence of trypanosomes was determined by microscopy, immunolog-ical rapid test VerY Diag and PCR coupled with High-Resolution Melt (HRM) analysis. A parametric test (ANOVA) was …

Temperature-Dependent Modelling And Spatial Prediction Reveal Suitable Geographical Areas For Deployment Of Two Metarhizium Anisopliae Isolates For Tuta Absoluta Management, Ayaovi Agbessenou, Komivi S. Akutse, Abdullahi A. Yusuf, Sospeter W. Wekesa, Fathiya M. Khamis

All Peer-Reviewed Publications

Tuta absoluta is one of the most devastating pests of Solanaceae crops in Africa. We previously demonstrated the efficacy of Metarhizium anisopliae isolates ICIPE 18, ICIPE 20 and ICIPE 665 against adult T. absoluta. However, adequate strain selection and accurate spatial prediction are fundamental to optimize their efficacy and formulations before field deployment. This study therefore assessed the thermotolerance, conidial yield and virulence (between 15 and 35 °C) of these potent isolates. Over 90% of conidia germinated at 20, 25 and 30 °C while no germination occurred at 15 °C. Growth of the three isolates occurred at all temperatures, but …

Mating Behaviour, Mate Choice And Female Resistance In The Bean Flower Thrips (Megalurothrips Sjostedti), Adeyemi O. Akinyemi, Sevgan Subramanian, David K. Mfuti, Tom W. Pope, Amanuel Tamiru, William D.J. Kirk

All Peer-Reviewed Publications

Many species of thrips (Thysanoptera) in the family Thripidae form mating aggregations, but the adaptive significance of these aggregations and the extent of male and female mate choice is poorly understood. We studied the mating behaviour of the bean flower thrips Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), which forms male aggregations and occurs across sub-Saharan Africa. We tested whether males choose mates by female age or mating status. No-choice mating bioassays with one male and one female were used to simulate the way males usually encounter only one female at a time in aggregations in the field. Virgin females violently resisted …

Whole Genome Comparisons Reveal Panmixia Among Fall Armyworm (Spodoptera Frugiperda) From Diverse Locations, Katrina A. Schlum, Kurt Lamour, Caroline Placidi De Bortoli, Rahul Banerjee, Robert Meagher, Eliseu Pereira, Maria Gabriela Murua, Gregory A. Sword, Ashley E. Tessnow, Diego Viteri Dillon, Angela M. Linares Ramirez, Komivi S. Akutse, Rebecca Schmidt-Jeffris, Fangneng Huang, Dominic Reisig, Scott J. Emrich, Juan Luis Jurat-Fuentes

All Peer-Reviewed Publications

Background: The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of > 80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). The population genomics of the United States (USA) fall armyworm remains poorly characterized to date despite its agricultural threat. Results: In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and USA were surveyed to further our understanding of …

Population Connectivity In Voles (Microtus Sp.) As A Gauge For Tall Grass Prairie Restoration In Midwestern North America, Marlis R. Douglas, Steven M. Mussmann, Tyler Chafin, Whitney J.B. Anthonysamy, Mark A. Davis, Matthew P. Mulligan, Robert L. Schooley, Wade Louis, Michael E. Douglas

Biological Sciences Faculty Publications and Presentations

Ecological restoration can promote biodiversity conservation in anthropogenically fragmented habitats, but effectiveness of these management efforts need to be statistically validated to determine ’success.’ One such approach is to gauge the extent of recolonization as a measure of landscape permeability and, in turn, population connectivity. In this context, we estimated dispersal and population connectivity in prairie vole (Microtus ochrogaster; N = 231) and meadow vole (M. pennsylvanicus; N = 83) within five tall-grass prairie restoration sites embedded within the agricultural matrix of midwestern North America. We predicted that vole dispersal would be constrained by the …

A Study Of The Diameter And Contraction Of King Spun-Yarns., Ismail Rakha, Rizk El-Bealy

Mansoura Engineering Journal

This paper presents some predicting formulas of yarn diameter and contraction of ring spun yarns. The study concerned the influence of twist multiplier, yarn count and bulk density. Experiments carried out on different cotton yarns to justify the results of the theoretical analysis. The results obtained with these empirical formulas agree satisfactorily with the actual data.

Fractional Factorial Treatment Of Ring Spun Yarn Quality., Fawkia El-Habiby, Rizk El-Bealy

Mansoura Engineering Journal

In the present work a study was made about the effect of the following five Parameters yarn linear density , spindle speed, /traveller size, top roller pressure and cradle opening on the quality of ring spun yarn. The experiments were carried out by varying each parameter at two levels using the fractional factorial technique (9). The experimental design treatment with the help of mini-computer programming was used to determine the effect of mean parameters and two factor interactions and interactions between two parameters were carried out by the method of variance analysis.

On Inter-Organizational Trust, Control And Risk In Transboundary Fisheries Governance, Gordon M. Hickey, Hunter T. Snyder, Jasper R. Devries, Owen Temby

School of Earth, Environmental, & Marine Sciences Faculty Publications

Inter-organizational collaboration is often considered essential to transboundary fishery governance, due, in part, to the high levels of task interdependence, the remote and often treacherous conditions, and the limited levels of information available to any policy actor on resource status. In the high seas, Regional Fisheries Management Organizations (RFMOs) are responsible for sustainably managing highly migratory and straddling fish stocks through the implementation of ecosystem-based approaches and ensuring adequate inter-jurisdictional cooperation. A central question facing RFMO governance is therefore how to structure and sustain inter-organizational transboundary collaboration under high uncertainty? This paper presents the case of the North Atlantic Salmon …