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Understanding The Influence Of Interfacial Chemistry In Core, Core/Shell And Core/Shell/Shell Quantum Dots On Their Fluorescence Properties, Omondi Bernard Omogo

Graduate Theses and Dissertations

Colloidal semiconductor nanocrystals (quantum dots) have received a great deal of attention due to their superior size tunable properties and promising applications in many areas. Some of the most practical areas of their applications include light emitting diodes (LED), photovoltaic and biological studies. Synthetic methods of these crystals is becoming more established with new strategies being reported every now and then. However, quantitative studies connecting the processes at the interface, namely core-ligand, core-shell and shell-shells, to the overall quantum dots fluorescence properties are not well understood. Specifically for cores, relating surface-atoms interactions, solvents, ligands nature, density and functional groups on …

Primocane-Fruiting Blackberry: Optimum N-Fertilization, Jose Carlos Reynoso Campos

Graduate Theses and Dissertations

This study was conducted in 2011 at the University of Arkansas, Fayetteville to determine the optimum rate and time of nitrogen (N) application for `Prime-Ark® 45' primocane-fruiting (PF) blackberries under high tunnel conditions. There were four N treatments: Control (0), 10, 10-split, and 20 kg*ha-1 (Treatments 1, 2, 3, 4, respectively). In a randomized complete block (RCB) design, the following variables were compared: total and marketable yield, fresh weight of plant above ground, and cane diameter. Total fruit yields for Treatments 2 and 3 (2.5 and 2.5 kg, respectively) were highest and significantly different from the other treatments (p< 0.05). Marketable yield had a similar trend as total fruit yield, although not significantly different. Cane diameter and plant fresh weight were not significantly affected by fertilizer treatments. There were not significant differences in N content in leaves among treatments. Results indicated that either a single or split N application of 10 kgN*ha-1 could result in better yields.

Four …

Estimating Nitrogen Fixation Rates, Importance, And Short-Term Efficiency In Small, Temperate Reservoirs Using Delta15n Techniques, Bryant Christopher Baker

Graduate Theses and Dissertations

Nitrogen (N2) fixation can give certain species of cyanobacteria a competitive advantage in lake and reservoir phytoplankton. These species of cyanobacteria, along with others that cannot fix N2, can form toxic compounds that impair water quality when present in high concentrations. N2 fixation rates may be substantial in small (< 1.0 km2), temperate reservoirs since these systems experience thermal stratification and often nitrogen (N) limitation throughout a substantial proportion of the year. However, the effects of N2 fixation on N cycling, alleviation of short-term N limitation, and water quality are not well-understood. A mesocosm experiment and ecosystem-scale observational study were conducted to 1) determine the efficiency of N2 fixation under varying N relative to phosphorus (P) supply, 2) examine the effects of N2 fixation on autotrophic biomass accumulation and microcystin production, and 3) measure N2 fixation rates and importance to autotrophic N demand and zooplankton N assimilation. Results of the mesocosm experiment indicated that N2 fixation was increased at low N:P supply under high P. However, N2 fixation was inefficient at alleviating N limitation when fixed N was the primary source of N. Additionally, microcystin production occurred only at high N:P supply when N2 fixation was low, indicating that reducing external N inputs may have a positive effect on water quality. Results of whole-reservoir determination of N2 fixation using seston δ15N natural abundances indicated that N2 fixation rates throughout the warm season were substantial and influenced by water temperature. Annual N2 fixation rates ranged from 2.2 - 6.6 g N m-2 yr-1, and contributed up to 19% of the annual autotrophic N demand. Zooplankton were assimilating fixed N in most of the study reservoirs, representing a possible mechanism of ecosystem fixed N retention. Collectively, these results suggest that N2 fixation plays a substantial role in N cycling in small, temperate reservoirs, but likely cannot alleviate short-term N limitation.

Efficacy Of Rice Insecticide Seed Treatments At Selected Nitrogen Rates For Control Of The Rice Water Weevil, Lissorhoptrus Oryzophilus Kuschel, Mallory Elise Everett

Graduate Theses and Dissertations

Seed-applied insecticides are the standard control method used to prevent rice water weevil (Lissorhoptrus oryzophilus Kuschel) injury to rice (Oryza sativa L.) roots, and often results in greater yields than rice that receives no seed-applied insecticide. Yield increases from seed-applied insecticides often occur even when insect pressure is low and should not cause yield loss. The research objective was to evaluate the effect of urea-nitrogen rate and seed-applied insecticide on number of rice water weevil larvae, nitrogen uptake and rice grain yield. Six trials were conducted at the Pine Tree Research Station (PTRS) and the Rice Research Extension Center (RREC) …

The Effects Of Maternal Information Transmission On Daughters' Responding To A Voluntary Hyperventilation Challenge, Ashley Arehart Knapp

Graduate Theses and Dissertations

Contemporary models of panic etiology would benefit from additional tests of how fear of internal cues is acquired. Drawing from literature suggesting parent-to-child verbal information transmission is one pathway by which fear of external stimuli is learned, the current study is designed to address the effects of this pathway on fearful responding to internal cues (i.e., somatic perturbation produced by a voluntary hyperventilation challenge). Specifically, 53 mothers of adolescent females between the ages of 10 and 14 years were randomly assigned to either share negative or positive information regarding their experience with a voluntary hyperventilation challenge prior to their daughters …

The Effects Of Fostering On Communication And Marital Quality In The Marital Dyadic Relationship, Katherine Elizabeth Russell

Graduate Theses and Dissertations

This study explores the phenomena of foster parents' marital relationships and the emotional stress felt by each spouse. Results revealed a positive correlation between marital quality and perceived spousal support and a negative correlation between either marital quality or perceived spousal support and emotional stress associated with disciplining the foster child. Analyses also showed that emotional stress associated with being a foster parent positively correlated with emotional stress associated with both the child's past and the possibility of the child being moved. These results underscore the importance of spousal communication, marital quality, and perceived spousal support as a stress reducer …

Improving Lamb Performance With Sericea Lespedeza And Molybdenum, Mohan Acharya

Graduate Theses and Dissertations

The objective of this research was to find the effect of prolonged feeding of sericea lespedeza (SL) supplemented with sodium molybdate on changes in body weight, serum and liver concentration of trace minerals (TM), hematology, serum biochemistry, and gastrointestinal parasites. Thirty ram lambs (Katahdin and ¾ Katahdin × ¼ Romanov) were weaned; blood, liver, and fecal samples were collected and signs of internal parasitic infection on lambs were recorded. Lambs were supplemented with 900 g of alfalfa (n = 10; CON) or SL (n = 20) based supplement for 103 d. Within the SL group, half of the lambs were …

Analysis Of Environmental Influences On Dressed Stone Decay: A Case Study Of Tafoni Development On A Hewn Djinn Block In Petra, Jordan, Kaelin M. Groom

Graduate Theses and Dissertations

Petra, Jordan captivates tourists and researchers with its dramatic sandstone cliffs, Nabatean, Roman, Byzantine and Roman architecture, and rich cultural heritage. However, increasing tourism in the valley is exacerbating stone degradation and complicating heritage management. This research analyzed environmental influences on dressed stone decay via tafoni development and evaluating cell evolution on an isolated hewn feature, known as Djinn Block X. Resembling other sandstone blocks found in the area, this irregular sandstone monument exhibits faces ranging in size from 2.5m by 3.5m to 3.9m to 4.2m (29m perimeter). Protruding features, incisions along the top, and a large platform attached to …

Tht And Capillary Electrophoresis To Monitor The Effects Of Solutions Conditions On Amylin Aggregation, Michael May

Graduate Theses and Dissertations

Amylin (hIAPP) aggregates have been found in 90% of patients with type II diabetes at autopsy, and are suspected to play a role in the death of islet &beta-cells¹. However, this aggregation process is not well understood. Here, we explore methods that utilize capillary electrophoresis (CE) as a means to better understand amylin's aggregation process.

We examined the effects of solutions conditions: agitation, pH, salt, and temperature on amylin aggregation using Thioflavin T, dot blots, and capillary electrophoresis. Thiofalvin T was used to predict the lag time to &beta-sheet formation. Our results indicated all variables with the exception …

Habitat Assessment Of Two Narrowly Endemic Plant Species, Ozark Spiderwort (Tradescantia Ozarkana) E. S. Anderson And Woods. And Newton's Larkspur (Delphinium Newtonianum) D. M. Moore, Autumn Lynn Coffey Olsen

Graduate Theses and Dissertations

The threat of biodiversity loss is upon us with the onset of climate change and our ever-demanding needs of the Earth's resources for a rapidly growing human population. Species highly vulnerable to loss are those limited in abundance and distribution, or those with reduced genetic diversity. Efforts to actively conserve a sensitive species require effectual data on the probable causes of their vulnerability. Two species of concern, Delphinium newtonianum and Tradescantia ozarkana, are globally rare endemic vascular plant species found only in the Interior Highlands of North America. In an attempt to understand the causes for their endemism, habitat …

Poultry Performance And Food Safety Impacts Of Selected Organic Acids And Probiotics, Anita Menconi

Graduate Theses and Dissertations

Improving production parameters and controlling foodborne pathogens have been challenges to the poultry industry. Salmonella has been the most common bacterial pathogen in laboratory confirmed foodborne illness cases, and contaminated poultry and poultry products have been identified as the most important source of transmission of Salmonella to humans. Therefore, research on effective interventions to reduce Salmonella transmission at the poultry production level has gained attention. Initially, a series of studies was conducted to evaluate the use of selected organic acids in controlling foodborne pathogens and improving poultry performance. Then, the characterization and application of lactic acid bacteria and Bacillus spp. …

Effects Of Petroleum Distillates On Amphibian Development, Kate Walker

Graduate Theses and Dissertations

Petroleum distillates are widely used as an energy source and the extraction and disposal of these chemicals are done with little consideration of their effects on aquatic environments. Amphibians are considered excellent ecological indicators but little research has examined effects of petroleum distillates on aquatic species. I evaluated the lethal and sublethal effects on larval amphibians with exposure to petroleum distillates associated with various venues of pollution including hydraulic fracturing. I selected three petroleum distillates (kerosene, oil, and unleaded gasoline) that are known to have negative effects on aquatic organisms and are similar to the common constituents of mixtures used …

Fertilizer Nitrogen Uptake Efficiency In Soft Red Winter Wheat And The Ability Of N-Star To Detect Alkaline Hydrolyzable Nitrogen In Crop Residues, Lana Aubrey Clark

Graduate Theses and Dissertations

Soil testing methods such as the Illinois Soil Nitrogen Test (ISNT) and Direct Steam Distillation (DSD) have been developed which measure alkaline hydrolyzable-N (AH-N) as a means of estimating potentially mineralizable-N. Crop residues play an important role in N cycling. However, the ability of the ISNT and DSD methods to determine AH-N within crop residues is unknown. Therefore, the first objective of this study was to determine the ability of the ISNT and DSD to quantify potentially mineralizable-N within five different crop residues common to Arkansas. Corn (Zea mays L.), soybean (Glycine max, L.), wheat, rice (Oryza sativa, L.), and …

Hope, Faith And Trust: Conversations With Tibetans In Exile, William Lukas Gramlich

Graduate Theses and Dissertations

The goal of Hope, Faith and Trust: Conversations with Tibetans in Exile was to create a documentary to serve as a platform for Tibetan refugees living in India to tell, in their own words, the story of the Tibetan peoples' political struggles since the Chinese government occupied Tibet in the 1950s. To achieve this goal, this project utilized oral-history interviews with Tibetan exiles, gathered as part of the University of Arkansas TEXT Program. The TEXT Program, short for Tibetans in Exile Today, is a study abroad oral-history project in which undergraduate students conduct interviews with Tibetans living in India. The …

Transcriptomic Insights Into The Diplontic Life History Of Diatoms, Colton Richard Kessenich

Graduate Theses and Dissertations

An organism's life cycle is the direct result of its evolutionary history and represents a fundamental aspect of its ancestry and ecology. Yet the process of linking alternating life-history stages has proven to be challenging, if not impossible in some cases. Diatoms (Bacillariophyceae) are no exception to this challenge, and their diversity of life stages and reproductive strategies add further challenges. A central focus of diatom research has been to unravel the evolutionary events that led to their extraordinary diversity, a line of inquiry that has been greatly aided by the availability of next-generation sequence data. Yet without proper taxonomic …

Rape Myths And Consent In College-Aged Southern Students, Amy Leanne Cofer

Graduate Theses and Dissertations

Rape and sexual assault are problematic issues for women on college campuses. Internal and external consent play a role in understanding sexual assault because sexual assault is defined as "nonconsensual sexual activity obtained through force, threats, intoxication, or intimidation." Factors related to understanding consent may include attitudes regarding sexual assault and rape, known as rape myths, which are defined as attitudes and false statements concerning rape that are widely known and accepted, mainly served to justify male sexual aggression towards women. The southeastern United States is known for being religiously and politically conservative, where gender roles are intertwined with a …

Comparing Virus Ultrafiltration Of Bacteriophages With Filtration Of Minute Virus Of Mice, Kent Smith

Graduate Theses and Dissertations

Industrial production of protein therapeutics demand rigorous testing and clearance of viruses. The U.S. Food and Drug Administration dictate the purity of pharmaceuticals with regards to viral contamination. As this testing is time consuming and expensive using mammalian cells and viruses, bacteriophages may provide a faster and cheaper alternative for membrane filtration processes. We used ultrafiltration membranes to filter protein solutions with viruses. Two bacteriophages were tested against membranes with two different pore sizes. These membranes were then tested by inverting the membrane's orientation. Flux measurements and log virus removal data were taken. Flux and log virus removal were seen …

The Relationship Of Goal Focus To Physical Distance, Job Title And Years Served Within The University Of Arkansas Division Of Agriculture, Christina Miller

Graduate Theses and Dissertations

The purpose of this study is to determine the relationship between physical distance from the headquarters, number of years working within the Division of Agriculture, and job title compared to mission statement and goal focus. The Division of Agriculture as part of the University of Arkansas System is a unique organization because many of its employees are not physically located at the headquarter locations of Little Rock and Fayetteville. The Cooperative Extension Service, part of the Division of Agriculture, has at least one office in each of Arkansas's 75 counties as well as faculty and staff members located at five …

21st Century Radicalization: The Role Of The Internet User And Nonuser In Terrorist Outcomes, David Wayne Woodring

Graduate Theses and Dissertations

This study examines differences between users and nonusers of information communication technologies (ICTs) within the pre-incident planning processes for domestic terrorist movements operating within the United States. In addition, this study is the first quantitative exploration of the prevalence, types, and purposes of ICT use within terrorist movements, specifically environmental, far-right, and Islamic extremist movements. Using "officially designated" federal terrorism investigations from the American Terrorism Study (ATS), we analyzed extracted evidence of ICT usage among individuals (n =331) engaged in the pre-incident planning processes as members of terrorist movements between 1995-2011. While we find significant differences in terrorist ICT use …

Infrared Energy Harvesting For Optoplasmonics From Nanostructured Metamaterials, Gregory Thomas Forcherio

Graduate Theses and Dissertations

Metamaterials exhibit unique optical resonance characteristics which permit precise engineering of energy pathways within a device. The ability of plasmonic nanostructures to guide electromagnetism offers a platform to reduce global dependence on fossil fuels by harvesting waste heat, which comprises 60% of generated energy around the world. Plasmonic metamaterials were hypothesized to support an exchange of energy between resonance modes, enabling generation of higher energy photons from waste infrared energy. Infrared irradiation of a metamaterial at the Fano coupling lattice resonance was anticipated to re-emit as higher energy visible light at the plasmon resonance. Photonic signals from harvested thermal energy …

Estimating Nitrogen Credits From Poultry Litter On Silt Loam Soils In Arkansas Using The Nitrogen-Soil Test For Rice: N-Star, Chester Eugene Greub

Graduate Theses and Dissertations

Rice (Oryza sativa L.) is one of the most important global cereal crops and is grown on a substantial number of hectares in Arkansas each year. Consequently, Arkansas is the leading rice producing state in the United States accounting for almost half of domestic production. The development and release of N-STaR (Nitrogen-Soil Test for Rice) allows producers to predict site-specific N fertilizer needs for rice production in Arkansas, with N-STaR being a predictor of potentially mineralizable-N. Furthermore, poultry production is a thriving commodity in Arkansas, producing a substantial amount of poultry litter (PL) annually. Rice producers are applying PL to …

Small Mammal Community Associations And Habitat Use At Pea Ridge National Military Park, Benton County, Arkansas, Christopher Reddin

Graduate Theses and Dissertations

Juniperus virginiana L. (Eastern Red Cedar) is a fire-intolerant tree species that has been invading and altering grassland ecosystems throughout the American Great Plains and Midwest. To see how Eastern Red Cedar encroachment affects small mammal communities, we surveyed small mammals using mark-recapture methods in Eastern Red Cedar forest and 5 other habitats common to the Ozark region. Additionally, we compared the microhabitat use of presumed juniper obligate Peromyscus attwateri J.A. Allen (Texas Mouse) and its conspecific P. leucopus Rafinesque (White-Footed Mouse). We ran over 7000 trap-nights and found that the small mammal species composition in Eastern Red Cedar was …

Porosity Development Within Lobes To Downslope Ramp Deposits On A Prograding Carbonate Shelf Of The Kinderhookian To Osagean Series In Northwest Arkansas, Elizabeth Marchese

Graduate Theses and Dissertations

Carbonate bodies with lobate geometries form a substantial part of the Osagean (early Mississippian) section in northwest Arkansas. The purpose of this study is to isolate and describe a single lobe from three-dimensional exposures in quarry walls to provide criteria by which lobe and lobe porosity can be recognized in the subsurface. Carbonate sediment generated on the Mississippian Burlington shelf moved southward by gravity flows from the shelf margin to positions on a prograding ramp in Arkansas where overlapping deposits with lobate geometries accumulated. These deposits are recognized in outcrops of the Boone Formation. Stratigraphic units within the Boone are …

Effect Of Limit-Fed Co-Product Feedstuffs On Production, Digestion, Fermentation And Rumen Function In Beef Cattle, William Brandon Smith

Graduate Theses and Dissertations

In terms of energy density, the cost of shipping hay is often not justified in yr where adverse conditions limit available forage. Our objective was to determine if co-product feedstuffs could be used to meet the energy demands for cows in late pregnancy. Eighty-six crossbred cows (527 ± 0.8 kg BW) in late gestation were stratified by BW, BCS and age and allocated randomly to 1 of 6 groups held on 2-ha dormant bermudagrass pastures for 68 d. Three groups were offered bermudagrass hay ad libitum (HAY) and three groups were offered 6.4 kg of soybean hulls (LSH) daily and …

Methane Emissions And Ammonia Volatilization From Drill-Seeded, Delayed-Flood Rice On A Silt-Loam Soil In Arkansas, Christopher Wade Rogers

Graduate Theses and Dissertations

The Environmental Protection Agency (EPA) currently uses a single methane (CH4) emissions factor of 160 kg CH4-C ha-1 for a primary rice (Oryza sativa L.) crop. The emissions factor is based on studies that do not adequately represent current management practices in Arkansas. Another concern is pre-flood fertilizer nitrogen (N) management, as the common N source, urea, is prone to loss via ammonia (NH3) volatilization. Thus, the objective of this research was to investigate trace gas emissions from rice on a silt-loam soil, including CH4 emissions as influenced by nitrogen (N) fertilization (i.e., optimal N and no N) in 2011, …

A Framework For Constructing Serious Games, Taylor Glen Yust

Graduate Theses and Dissertations

Communicating ideas and knowledge through serious games is a trend that is currently gaining in popularity. However, at present, there is a distinct lack of a game development methodology that takes a critical approach to transforming information into gameplay. This thesis presents a framework that can be followed to construct compelling serious games that are effective at transferring knowledge to the player. This is accomplished through an analysis of atomic knowledge items and their relationships to one another, followed by a meaningful and synergetic implementation of these ideas at a foundational mechanics level.

This thesis also describes the development of …

Participation In Recreation And Leisure Activities In Long-Term Care Facilities And Health Related Quality Of Life, James Michael Duncan

Graduate Theses and Dissertations

The purpose of this paper was to examine predicted variations in Health Related Quality of Life (HRQoL) among individuals over the age of 65 residing in Long Term Care (LTC) facilities. Variables related to self-care, depression, gender, social support, and leisure activities were examined. Univariate analysis was conducted from data collected from 110 LTC residents from 15 assisted living facilities (ALF) and nursing homes (NH) throughout Arkansas and a standard multiple regression was employed. Linear combinations of independent variables were significantly correlated to variations of HRQoL. More specifically, higher ratings in depression were positively correlated to lower ratings of HRQoL. …

The Effects Of Apoe Knock Out On Skeletal Muscle Regeneration: A Look Into Markers Of Protein Synthesis And Satellite Cell Function, Joshua Eden Ragland

Graduate Theses and Dissertations

ApoE helps regulate serum cholesterol levels by adding in transport of cholesterol into the cells, as well as, to the liver. ApoE knockout mice (ApoE KO) present a model that demonstrates the effects of hypercholesterolemia. Damage to muscle stimulates a complex regenerative response. The effects of high cholesterol on this regenerative response are not known. PURPOSE: To determine if skeletal muscle regeneration is altered in apoE KO mice by measuring protein synthesis regulator IGF-1, Akt, mTOR, and p70S6K, cell cycle regulator cyclin D1, and myogenic regulatory factors myoD and myogenin. METHODS: Female C57/BL6 (WT) and apoE KO were assigned to …

Milling And Functional Properties Of Co-Mingled Rice Cultivars, Nikhil N. Basutkar

Graduate Theses and Dissertations

Differences have been observed in the milling and functional properties of different rice cultivars, particularly between hybrid and pureline cultivars. Co-mingling of rice cultivars commonly occurs during harvest, storage and drying operations. Thus, there is a need to study the effect of co-mingling on the milling and functional properties of rice cultivars. Two long-grain, hybrid (H) cultivars CL XL745 and CL XL729 and two long-grain, pureline (P) cultivars CL 151 and Wells were used to prepare CL XL745/CL 151 (H/P), CL XL745/CL XL729 (H/H) and Wells/CL 151 (P/P) co-mingles, mixed in various proportions. Milled rice yield (MRY), head rice yield …

Identifying, Monitoring, Quantifying And Converting Algae To Bio-Fuels In Bio-Reactors, Alice C. Jernigan

Graduate Theses and Dissertations

Growing algae as a source for bio-fuels has become an area of interest due to concerns about global warming and the reliability and ecology of the production of fossil fuels. Dried algae harvested from a pilot water quality improvement technology at the Rockaway Wastewater Treatment Facility in New York were examined as a source of carbohydrates and lipids for the production of bio-fuels in bio-reactors. The length of storage time, storage conditions, sugar and lipid extraction processes, and fuel production were studied. The results show that if the algae is stored dry (0.015 g/g algae even after a year in …