Digital Commons Network^™

What's Going On Here, Joanna R. Pike

Graduate Theses and Dissertations

This project is an installation depicting shirts and pants in various degrees of Recognizability. The Components vary from somewhat Unrecognizable to entirely Unrecognizable; Bumps and Blocks are interspersed and interrupt the Semi-logic of What’s going on here while adding repetitive elements to clarify the existence of the Semi-logic. The arrangement of the Components in the installation makes the Unrecognizable forms surrounded by the In-between Space into somewhat Recognizable versions of shirts and pants. The viewer does not fully recognize all the Components, but instead understands the implied Recognition given their existence within the installation. The ideas of Lists, Patterns, Systems, …

The Influence Of Singlet Oxygen And Loss Of Function Of Fatty Acid Desaturase 7 In The Chloroplast On Aphid Resistance In Arabidopsis Thaliana, Hillary Donna Fischer

Graduate Theses and Dissertations

Fatty Acid Desaturase 7 (FAD7) is a chloroplast-localized enzyme that alters the fatty acid content of photosynthetic membranes, and that negatively regulates plant defenses against aphids. Previous studies in the model organism Arabidopsis (Arabidopsis thaliana) have shown that loss-of-function mutations in FAD7 decrease population growth of the green peach aphid (GPA; Myzus persicae Sulzer). This study further characterized the effects of a fad7 null mutant on aphids, and investigated the role of reactive oxygen species (ROS), including singlet oxygen (1O2), in plant responses to aphid resistance in fad7 as well as in wild type plants and a mutant with heightened …

Development Of An Ultraviolet Absorbance Assay To Estimate Air Entrainer Dosing For Concrete Containing Fly Ash, James Spencer

Graduate Theses and Dissertations

Fly ash is a coal combustion byproduct that can be used as a supplementary cementitious material (SCM) in concrete, offering benefits such as increased workability, durability, and strength. Fly ash can be used as a partial replacement to cement, reducing concrete productions costs and decreasing disposal in landfills. However, variability of fly ash properties (e.g., carbon content, adsorption site density) confounds estimates of the air entraining admixture (AEA) dose needed to achieve a specified air content in concrete. Air entrainment is needed to improve freeze-thaw resistance and limit concrete cracking. The foam index (FI) test is currently used to estimate …

Quality Determinates Of Rice Price In Open Bag Markets In Sub-Saharan Africa, Bailey Peterson-Wilhelm

Graduate Theses and Dissertations

Weaknesses in the grades and standards system in low-income countries across Sub-Saharan Africa undermine the transparency of agricultural markets. In the Democratic Republic of the Congo (DRC), Ghana and Mozambique rice is predominately sold in open bags and if rice price does not reflect its quality, then inefficiencies may lead to consumer welfare losses. Importantly, it is possible that impoverished communities are priced out of the market due to inflated and inefficient prices. The objective of this study is to examine determinates of rice price by estimating the impact of selected rice quality attributes on rice prices in DRC, Ghana …

The Story Of A Journey: Awakenings Before, During And After The Zoom Production Of The Play Thrift Store Junkie, Brendan Beseth

Graduate Theses and Dissertations

This thesis tells the story of several awakenings I had while pursuing my M.F.A. in playwriting at the University of Arkansas. It details some of the traps a writer can fall into. It tells of how to get out of the quicksand. Also contained within is an account of the thesis production of my play Thrift Store Junkie and the play’s script.

Molecular And Genetic Studies Of Robo2 Transcriptional Regulation In The Central Nervous System Of Drosophila Melanogaster, Muna Abdal Rahim Abdal Rhida

Graduate Theses and Dissertations

Drosophila Robo2 axon guidance receptor is a member of the evolutionarily conserved Roundabout (Robo) protein family that is involved in directing axons that cross the midline to the other side of the animal body. Robo2 roles mainly depend on two factors: The functional domains of the Robo2 protein, which is extensively studied, and the dynamic transcription of robo2 in various subsets of cells throughout embryogenesis which is not fully understood. Thus, knowing robo2 enhancers that transcriptionally regulate robo2 during embryogenesis is significant. To investigate robo2 potential enhancers, we screened 17 transgenic lines of Drosophila that were generated by Janelia Research …

Resistance Screening And Association Mapping For Resistance To The Downy Mildew Pathogen Of Spinach, Dotun Olaoye

Graduate Theses and Dissertations

Spinach is an important cool leafy vegetable cultivated around the world, with large scale production in California and Arizona in the U.S. Spinach is a highly nutritious vegetable beneficial in the human diet. Spinach is affected by a number of biotic stressors. Downy mildew, caused by the oomycete pathogen Peronospora effusa, is a major threat to spinach as it affects the leaf quality and impacts the economic value of spinach. Several efforts have led to the development of resistant genotypes/cultivars to this pathogen. However, few studies have examined the genetics of resistance to the downy mildew pathogen in detail. This …

Telepractice In The Communication Treatment Of Individuals With Post-Stroke Aphasia: Systematic Review, Gayanthi Kodituwakku-Wewalwala

Graduate Theses and Dissertations

Telepractice, a branch of telehealth, which is the delivery of services to distant sites employing telecommunication, has been developing rapidly nowadays. Owing to the nature of the condition and treatment foci in aphasia, telepractice has been identified as a potential mode for intervention to persons with aphasia (PWA) in the field of speech-language pathology. Based on the American Speech-Language Hearing Association (2005), telepractice is considered a means to extend services to a wider context overcoming the barriers of transportation, costs, and limited availability of services. Thus, exploration of treatment accessibility to underserved populations in middle/low-income countries or rural areas via …

Crop Response To Low-Dose Dicamba, Mason Castner

Graduate Theses and Dissertations

The introduction of dicamba-resistant (DR) soybean [Glycine max (L.) Merr.] and cotton (Gossypium hirsutum L.) followed by a label allowing over-the-top applications of dicamba in the 2017 provided growers an additional option for broadleaf weed control. Because non-DR soybean is sensitive to low concentrations of dicamba, postemergence dicamba applications present growers choosing to plant non-DR soybean with concerns of damage from off-target movement through physical drift and volatilization of the herbicide as well as tank-contamination from prior dicamba application. Consequences of low-dose dicamba exposure on sensitive vegetative and reproductive soybean have been well researched, but little is known regarding the …

An Eeg Source-Space Analysis Of The Neural Correlates Underlying Self-Regulation, Stephanie M. Long

Graduate Theses and Dissertations

Self-regulation is the cognitive process of controlling our thoughts and behaviors to be aligned with our goals. This process is used in many different contexts and has been associated with contributions from several brain regions. This research aimed to investigate differences in four prefrontal areas of the brain while participants applied four different self-regulation strategies. We recorded EEG while participants (N = 132) performed three tasks which engaged each of the four self-regulation strategies: the AX-CPT task engaged proactive and reactive control, the Go/Nogo task engaged inhibitory control, and the hybrid Flanker Global/Local task engaged the resolution of response conflict. …

Quantum Dynamical Phenomena In Non-Hermitian And Magnomechanical Systems, Saeid Vashahri Ghamsari

Graduate Theses and Dissertations

In this dissertation, we have investigated quantum dynamics via three case studies. First, we studied a system of two coupled waveguides respectively carrying optical damping and optical gain in addition to squeezing elements in one or both waveguides. Such a system is expected to generate highly entangled light fields in the two waveguides. We, however, show that the degree of the created entanglement is significantly affected by the quantum noises associated with the amplification and dissipation. Because of the noise effect, one can only have nonzero entanglement for a limited time interval. Second, we generalized the first project by considering …

Study Of Static And Dynamical Properties Of Complex Antiferroelectrics Materials, Kinnary Yogeshbhai Patel

Graduate Theses and Dissertations

The aim of this dissertation is the investigation of the static and dynamical properties of the complex antiferroelectric materials using Effective Hamiltonian method and First principles calculations. In chapter 3, a novel elemental interatomic coupling in perovskite materials which bilinearly couples the antiferroelectric displacements of cations with the rotations of the oxygen octahedra. This new coupling explains a very complex crystal structure of prototypical antiferroelectric PbZrO3. My explanation provides a unified description of many other complex antipolar crystal structures in variety of perovskite materials, including the occurrence of incommensurate phases in some of them. In chapter 4, results and analysis …

Spatial Assessment Of Urban Growth In Cities Of The Decapolis; And The Implications For Modern Cities, Wade A. Pierson

Graduate Theses and Dissertations

The Levant’s Decapolis was a network of ten cities in Greco-Roman Israel, Jordan, and Syria that established a thriving economic community. The Decapolis was home to ancient and modern cities like Damascus (Dammásq) and Amman (Philadelphia). Despite the various origins of these cities, Roman administration and their city planners oversaw the implementation of idealized Roman city form throughout the region. Three Decapolis cities represent intriguing examples of the larger confederation. Philadelphia (Amman), Gerasa (Jerash), and Gadara (Umm Qais) represent cities of common original urban form which developed drastically diverse urban morphologies over time.

Spatial analyses of these cities required working …

Building-Level Administrators And Collaborative Special Education Iep Meetings: Addressing Barriers To Active And Inclusive Participation, Trevor A. Addis

Graduate Theses and Dissertations

The purpose of this study was to identify the factors serving as barriers to effective building-level administrator participation in special education individualized education program (IEP) meetings. For the purposes of this study, research was conducted in the multidisciplinary areas of social cognitive theory and self-efficacy, along with an examination of school-building administrators as instructional leaders, the role(s) of building-level leadership in special education and building administrator knowledge and understanding of special education policies and practices. A qualitative research approach was used to examine local building-level administrator participation in the special education IEP process. Building Level Administrators, in the district were …

Starter Nitrogen Source And Preflood Nitrogen Rate Effects On Rice Grown On Clay Soils, Linda Rachelle Martin

Graduate Theses and Dissertations

Seedling rice (Oryza sativa L.) grown on clayey-textured soils generally develops slowly as compared to loamy-textured soils. Our research examined the effects of starter-N source and preflood-N rates on canopy closure, total aboveground N uptake, and grain yield of rice grown on clayey-textured soils. Eleven field trials were established in Arkansas and Mississippi including five trials with a hybrid cultivar and six trials using a pure-line cultivar. Starter-N sources included no starter-N (NONE), ammonium sulfate (AMS), diammonium phosphate (DAP), and urea (UREA) applied at 24 kg N ha-1 at the rice 2-leaf stage and five preflood-N rates ranging from 0-224 …

Characterization Of Gesn Semiconductors For Optoelectronic Devices, Hryhorii Stanchu

Graduate Theses and Dissertations

Germanium-tin alloys with Sn compositions higher than 8 at. % to 10 at. % have recently attracted significant interest as a group IV semiconductor that is ideal for active photonics on a Si substrate. The interest is due to the fact that while at a few percent of Sn, GeSn is an indirect bandgap semiconductor, at about 8 to 10 at. % Sn, GeSn transitions to a direct bandgap semiconductor. This is at first surprising since the solid solubility of Sn in Ge under equilibrium growth conditions is limited to only about 1 at. %. However, under non-equilibrium growth conditions, …

Memory Module Design For High-Temperature Applications In Sic Cmos Technology, Affan Abbasi

Graduate Theses and Dissertations

The wide bandgap (WBG) characteristics of SiC play a significant and disruptive role in the power electronics industry. The same characteristics make this material a viable choice for high-temperature electronics systems. Leveraging the high-temperature capability of SiC is crucial to automotive, space exploration, aerospace, deep well drilling, and gas turbines. A significant issue with the high-temperature operation is the exponential increase in leakage current. The lower intrinsic carrier concentration of SiC (10-9 cm-3) compared to Si (1010 cm-3) leads to lower leakage over temperature. Several researchers have demonstrated analog and digital circuits designed in SiC. However, a memory module is …

Statistical Machine Learning For Breast Cancer Detection With Terahertz Imaging, Tanny Andrea Chavez Esparza

Graduate Theses and Dissertations

Breast conserving surgery (BCS) is a common breast cancer treatment option, in which the cancerous tissue is excised while leaving most of the healthy breast tissue intact. The lack of in-situ margin evaluation unfortunately results in a re-excision rate of 20-30% for this type of procedure. This study aims to design statistical and machine learning segmentation algorithms for the detection of breast cancer in BCS by using terahertz (THz) imaging. Given the material characterization properties of the non-ionizing radiation in the THz range, we intend to employ the responses from the THz system to identify healthy and cancerous breast tissue …

Short-Term Effects Of Winter Cover Crops On Soil Properties, Yield, And Partial Returns In A No-Tillage Soybean Rotation, Drew Dillon Kirkpatrick

Graduate Theses and Dissertations

Cover crops have the potential to provide many benefits including weed suppression, erosion control, and improvements to soil quality. These benefits can be affected by species, biomass accumulation, and management practices. Although large amounts of biomass are good for maximizing benefits, it can result in problems for establishing the subsequent crop. Soybean [Glycine max (L.) Merr.] accounts for over 50% of Arkansas crop hectares annually; therefore, understanding the effect that a cover crop can have on the following soybean crop is crucial to the successful implementation of cover crops within the state. A study was established to evaluate winter cover …

Non-Volatile Memory Adaptation In Asynchronous Microcontroller For Low Leakage Power And Fast Turn-On Time, Jean Pierre Thierry Habimana

Graduate Theses and Dissertations

This dissertation presents an MSP430 microcontroller implementation using Multi-Threshold NULL Convention Logic (MTNCL) methodology combined with an asynchronous non-volatile magnetic random-access-memory (RAM) to achieve low leakage power and fast turn-on. This asynchronous non-volatile RAM is designed with a Spin-Transfer Torque (STT) memory device model and CMOS transistors in a 65 nm technology. A self-timed Quasi-Delay-Insensitive 1 KB STT RAM is designed with an MTNCL interface and handshaking protocol. A replica methodology is implemented to handle write operation completion detection for long state-switching delays of the STT memory device. The MTNCL MSP430 core is integrated with the STT RAM to create …

Poems And Translations, Rome Hernández Morgan

Graduate Theses and Dissertations

This document is separated into two parts, a collection of original poems and a collection of translations of the crônicas of Rubem Braga. The collection of poems, titled, “Because I Never See You,” attempt to parse the complexities of familial and intimate relationships, addiction, and BIPOC experience. The collection of translations attempts to offer a small sample of the crônicas of Rubem Braga (1913-1990), a Brazilian journalist who is known throughout Brazil for “elevating” the form of the crônica from ephemera to the literary.

Geospatial Analysis Of Registered Sex Offenders: A Case Study From Pulaski County, Arkansas, Maggie Rose Bridges

Graduate Theses and Dissertations

The objective of this case study was to analyze the spatial distribution patterns of the residences of registered sex offenders in Pulaski County, Arkansas to determine the impact of state enforced residence restrictions. Density and clustering factors were used to identify census tracts of the study area with high and low concentrations of offenders. These zones were then compared to identify which characteristics were similar and dissimilar between high and low concentration zones. The results indicate that there is a non-random distribution of registered sex offenders in the study area. The findings also indicate that the residence restrictions placed on …

Immersive Systems And User Engagement Through Neurois Lens, Ali Balapour

Graduate Theses and Dissertations

Immersive systems (e.g., Virtual Reality) are at the forefront of the next generation of innovative technologies. Recent technological advancements have made them viable for businesses and individuals to adopt. For example, some realtors now offer virtual house tours in the absence of walk-ins. The concept of “immersion” is at the heart of these technologies. However, despite the fact that this concept has been studied for almost three decades, our understanding remains weak and inconsistent. Specifically, there remains a lack of consensus on what it is, its antecedents, and how it should be measured.

This dissertation includes two essays. In Essay …

Chronic Absenteeism At One Arkansas High School, Michelle Miller

Graduate Theses and Dissertations

Chronic absenteeism is a fairly new concept in education. Many schools have only started tracking chronic absenteeism with the start of Every Student Succeeds Act. The following research studied chronic absenteeism at an Arkansas High School, which answered the two research questions in this study. The first research question studied the demographics of the chronically absent student which included grade level, race/ethnicity, Special Education and English Language Learner status, and free or reduced lunch status. The second research question studied the class period of the chronic absence which included the time of day and type of class. High School X …

Low-Power And Reconfigurable Asynchronous Asic Design Implementing Recurrent Neural Networks, Spencer Nelson

Graduate Theses and Dissertations

Artificial intelligence (AI) has experienced a tremendous surge in recent years, resulting in high demand for a wide array of implementations of algorithms in the field. With the rise of Internet-of-Things devices, the need for artificial intelligence algorithms implemented in hardware with tight design restrictions has become even more prevalent. In terms of low power and area, ASIC implementations have the best case. However, these implementations suffer from high non-recurring engineering costs, long time-to-market, and a complete lack of flexibility, which significantly hurts their appeal in an environment where time-to-market is so critical. The time-to-market gap can be shortened through …

Social Acceleration In The Marketplace: Three Essays Exploring The Intersection Of Culture And Consumption, Sarah Grace

Graduate Theses and Dissertations

Consumer culture is fast. Goods, services, people, ideas, and values – the material and nonmaterial aspects of culture – are moving more quickly throughout the marketing system than ever before. Such acceleration effects diverse stakeholders: people, public, and planet. This dissertation explores the phenomenon of ‘social acceleration’, and specifically, the ‘acceleration of the pace of life’ which examines the feeling that time is going faster in modern societies as a result of “the increase of action episodes per unit of time” (Rosa 2013, 80). This project develops an understanding of how meanings in marketing are socially constructed in relation to …

Factors Influencing Stakeholder Support Of A Bond Referendum In A Rural Kansas School District, Joshua M. Woodward

Graduate Theses and Dissertations

The purpose of this study is to examine factors that influence stakeholder support of bond elections targeted for capital improvements in a rural school district in Kansas. The study uses existing research to identify factors that influence school bond referendum success. To better understand the factors identified in the research literature that influence stakeholder support in the focus district, data were gathered from stakeholders within the school district of focus through a perceptual survey and focus group interviews.

The availability of research on school bond referendum success and failure is plentiful. However, specific research on factors that influence rural school …

Securing Fog Federation From Behavior Of Rogue Nodes, Mohammed Saleh H. Alshehri

Graduate Theses and Dissertations

As the technological revolution advanced information security evolved with an increased need for confidential data protection on the internet. Individuals and organizations typically prefer outsourcing their confidential data to the cloud for processing and storage. As promising as the cloud computing paradigm is, it creates challenges; everything from data security to time latency issues with data computation and delivery to end-users. In response to these challenges CISCO introduced the fog computing paradigm in 2012. The intent was to overcome issues such as time latency and communication overhead and to bring computing and storage resources close to the ground and the …

Surface Modified Polypropylene Membranes For Treating Hydraulic Fracturing Produced Waters By Membrane Distillation, Tharaka Hawpe Gamage

Graduate Theses and Dissertations

Membrane distillation is an emerging technology for treating hydraulic fracturing flowback and produced waters. Suppression of membrane fouling by inorganic and polar and non-polar organic compounds is a challenge. Here polyhydroxyethyl methacrylate, polyacrylic acid, polvinylallyl imidazolium bromide and polyvinylhexyl imidazolium bromide chains have been grafted from the membrane surface. Fouling is initially due to adsorption of organic compounds followed by scale formation. When challenged with produced water, membranes modified with polvinylallyl imidazolium bromide chains provided the greatest resistance to fouling. For EC pretreated produced water and synthetic produced water that contained mainly inorganic species, the flux decline was much less.

Si-Based Germanium Tin Photodetectors For Infrared Imaging And High-Speed Detection, Huong Tran

Graduate Theses and Dissertations

Infrared (IR) radiation spans the wavelengths of the windows: (1) near-IR region ranging from 0.8 to 1.0 μm, (2) shortwave IR (SWIR) ranging from 1.0 to 3.0 μm, (3) mid-wave IR (MWIR) region covering from 3.0 to 5.0 μm, (4) longwave IR (LWIR) spanning from 8.0 to 12.0 μm, and (5) very longwave IR extending beyond 12.0 μm. The MWIR and LWIR regions are important for night vision in the military, and since the atmosphere does not absorb at these wavelengths, they are also used for free-space communications and astronomy. Automotive and defect detection in the food industry and electronic …