Digital Commons Network^™

A Comparison Of Student Final Grades In College Algebra Based On Face-To-Face And Online Course Modalities, Christopher Michael Lafata

Graduate Theses and Dissertations

As community colleges emerge from the COVID-19 pandemic there may be a tendency to rely on technology to facilitate more online coursework. Online education has been a fixture of higher education since the mid-1990s, but there’s always been a question as to whether it is effective as traditional, face-to-face coursework. This is especially important in College Algebra, already viewed as a barrier course for many students. If more students take College Algebra online, will the results be as good as students taking the course in a classroom? The purpose of this quantitative causal-comparative study is to identify the relationship between …

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

Adult Students’ Willingness To Communicate In The Esl/Efl Language Classroom: A Literature Review, Lisa N. Moreno

Graduate Theses and Dissertations

The objective of this study was to survey the literature on what hinders and promotes willingness to communicate in the English /Foreign language classroom. Twenty-five articles published between 2017-2022 were evaluated in this study. The review of literature concentrated on foreign language students who are studying in a higher education setting or adults who are studying English in a Literacy Center setting. Findings indicated that the student’s psychological state played a major part in a student’s willingness to communicate. This includes self-efficacy, anxiety, emotions, trust, and motivation. A student’s involvement in the learning process determines a student’s ability to communicate. …

Thermal Inactivation Kinetics Of Salmonella In Milk Powder As Impacted By Water Activity And Powder Type, Erika Litta Kadas

Graduate Theses and Dissertations

Historically, low-water activity (aw) foods (aw <0.65) were considered to be microbiologically safe for consumption. However, these foods have been implicated in outbreaks of pathogens such as Salmonella enterica, at a frequency that surely challenges this assumption of safety. Although usually implicated in outbreaks involving poultry and egg products, Salmonella spp. have frequently been the culprit in several outbreaks and recalls associated with low-water activity foods (LWAF) due to contamination resulting from the environment, animals, or even the employees during pre-or post-processing. One such LWAF that has been associated with Salmonella spp. outbreaks is milk powder. Milk powders are used in a variety of products ranging from infant formula to confectionary goods. With their widespread use, improving their safety is imperative. A key step in improving their safety is to thoroughly investigate preventive controls related to milk powder processing. The Food Safety Modernization Act (FSMA) established the Preventive Controls for Human Foods Rule, which mandates that processors design and establish a food safety plan outlining any potential hazards and the steps they will take to ensure those hazards do not compromise the safety of the product. Presently, the dairy industry does not have an established kill-step for milk powders post-spray drying. Spray drying may reduce some microbial populations, however, desiccation(e.g., spray drying) is not considered a kill-step. The work outlined in this thesis aims to assist our dairy industry partners in establishing their own thermal process for milk powders post-spray drying. Moisture sorption isotherms of two milk powders (nonfat dry milk: NFDM and a milk protein concentrate with 85% protein content: MPC-85) were determined and showcased that the temperatures at which the isotherms were determined (23, 40, or 60°C) significantly affected both the adsorption and desorption isotherms (p<0.0001) for each powder. Secondly, the thermal inactivation kinetics of Salmonella spp. in both powders were evaluated at two different water activities (0.20 and 0.30) and three temperatures (75, 80, and 85°C) to determine the effect of water activity on the thermal resistance of a cocktail of Salmonella spp. The D-values of Salmonella were heavily influenced by the thermal treatment temperature (p< 0.0001), but not the water activity (p >0.05). The overall findings contained within this thesis provide valuable information about the thermal inactivation kinetics of Salmonella spp. to our partners in the dairy industry so that they may implement an appropriate thermal process for their milk powders.

Multivariate Fairness For Paper Selection, Reem Alsaffar

Graduate Theses and Dissertations

Peer review is the process by which publishers select the best publications for inclusion in a journal or a conference. Bias in the peer review process can impact which papers are selected for inclusion in conferences and journals. Although often implicit, race, gender and other demographics can prevent members of underrepresented groups from presenting at major conferences. To try to avoid bias, many conferences use a double-blind review process to increase fairness during reviewing. However, recent studies argue that the bias has not been removed completely. Our research focuses on developing fair algorithms that correct for these biases and select …

In-Field And Greenhouse Assessments Of A Selection Of Preemergent Herbicides On Newly Planted Blackberries, Kayla Knepp

Graduate Theses and Dissertations

This field trial assesses some of the preemergence herbicide options available to growers and their effect on newly transplanted blackberries (Rubus L. subgenus Rubus Watson). Weed control has recently been surveyed as a top priority for blackberry growers; however, limited preemergence herbicides are registered for new blackberry plantings. Weed control is an ongoing component of blackberry production and with few in-season postemergence herbicide options available, growers rely on preemergence herbicides to maintain clean fields. The preemergent herbicides assessed in this trial were chosen with the intention to broaden the chemical control options available to growers in new plantings. A two-year …

The Evolution Of X-Ray Binaries And Their Accretion States, Lacey A. West

Graduate Theses and Dissertations

X-ray binary systems (XRBs) consist of a compact object component (e.g., black hole or neutron star) that accretes matter from a companion star. Although the extent to which XRBs contributed to the early heating of the intergalactic medium is still under investigation, it is estimated that XRBs dominated the X-ray radiation field before the reionization epoch. The study of XRB emission is therefore crucial to our understanding of the very early universe. Furthermore, studying the abundance and radial distribution of each XRB type within a galaxy can be revealing of the host galaxy’s local properties, structure, and evolution. XRB spectra …

Movie Reviews Sentiment Analysis Using Bert, Gibson Nkhata

Graduate Theses and Dissertations

Sentiment analysis (SA) or opinion mining is analysis of emotions and opinions from texts. It is one of the active research areas in Natural Language Processing (NLP). Various approaches have been deployed in the literature to address the problem. These techniques devise complex and sophisticated frameworks in order to attain optimal accuracy with their focus on polarity classification or binary classification. In this paper, we aim to fine-tune BERT in a simple but robust approach for movie reviews sentiment analysis to provide better accuracy than state-of-the-art (SOTA) methods. We start by conducting sentiment classification for every review, followed by computing …

A Multi-Criteria Ranking System For Prioritizing Maintenance Of Levee Systems In Arkansas, Nguyen Danh Phan

Graduate Theses and Dissertations

There are 208,009 properties in Arkansas that have more than a 26% chance of being severely affected by flooding over the next 30 years, which represents 13% of all properties in the state. A levee system is designed to reduce the flooding risk for urban and rural communities; however, most of the state's levees have been significantly outdated or built with engineering standards less rigorous than current best practices. The Levee Safety Action Classification (LSAC), as recorded in the National Levee Database (NLD), communicates the risk associated with living behind a particular levee and assists local, state, and federal stakeholders …

Development Of Deep Shear Wave Velocity Profiles And An Approach To Generate Site Signature Consistent Pseudo Shear Wave Velocity Profiles In The Mississippi Embayment, Ashraf Kamal Himel

Graduate Theses and Dissertations

This dissertation details the development of a surface wave method (SWM) technique to generate deep shear wave velocity profiles (VS profiles), applying this technique at 24 sites across the Mississippi embayment and developing an approach to generate pseudo site signature consistent VS profiles from velocity functions and fundamental frequency. In the presented SWM technique, active and passive source surface wave measurements are inverted along with fundamental frequency to develop a site signature consistent VS profile. Multiple transformation methods, including MSPAC, HRFK and FK are used to resolve experimental dispersion data from surface wave measurements. SWM VS profile at the Central …

Initial Exploration Of Reduced Gyrations For Arkansas Asphalt Mix Designs, Jocie L. Baker

Graduate Theses and Dissertations

The most common distresses in asphalt pavement are cracking and rutting. These distresses plague almost every asphalt roadway in the world. Finding ways to mitigate these distresses will improve the performance of asphalt pavements. One way to combat the premature cracking of asphalt in the field is to ensure there is enough asphalt binder within the mix. This will help the flexibility of the asphalt undergoing large loads and deformation. However, it is widely accepted that mix designs across the country lack the appropriate amount of asphalt binder in their mixes, causing dry mix designs that are subject to cracking …

Hostages Of The Crisis: Iranian Students And Jimmy Carter, Timothy Will Teague

Graduate Theses and Dissertations

Hostages of the Crisis: Iranian Students and Jimmy Carter discusses President Carter’s decision in 1979 to order the Immigration and Naturalization Service to assess the approximately 56,000 Iranian students in the United States for deportation after the seizure of the American embassy in Tehran, Iran. This works begins with a discussion of the development of the nation’s immigration system, examining how it was born as a result of anti-Chinese xenophobia in the late nineteenth century and how it matured with nativistic immigration laws in the first half of the twentieth century. Immigration policy was often influenced by xenophobic sociopolitical pressure …

Xps And Ipe Determination Of Band Offsets Of Germanium Based Materials, Justin Michael Rudie

Graduate Theses and Dissertations

Germanium tin and silicon germanium tin are group IV semiconductor alloys that have gained significant interest in recent years for their potential use in optoelectrical devices. While silicon and germanium are indirect bandgap materials on their own, alloying them with tin in sufficient quantities leads to a transition to direct bandgap alloys. Direct gap performance opens the door for efficient light emitting and detecting devices fabricated entirely on group IV materials that are compatible with the industry standard CMOS manufacturing techniques. Germanium tin and silicon germanium tin have bandgaps that respond to light in the mid to near infrared spectrum …

The Effects Of Physical Function And Genetics On Cognition And Blood Biomarkers In Individuals At-Risk For Alzheimer’S Disease And Related Dementias, Joshua Louis Gills

Graduate Theses and Dissertations

Alzheimer’s disease and related dementia (ADRD) rates are expected to triple by the year 2050. Early detection and specific mitigation efforts are warranted to blunt the alarming rate. Physical function (PF) declines with age, but higher physical function is associated with better cognitive functioning in middle-to- older age individuals. Moreover, greater physical activity (PA) is associated with better global cognition; however, Apoliporotein e4 carriers may not gain the same benefits with exercise. Additionally, plasma phosphorylated tau 217 (p-tau217) has been identified as a novel diagnostic ADRD biomarker which needs further research to examine associations with risk factors. Therefore, the aims …

Materials Design For Energy Applications Using Ab- Initio Calculations, Hind Hemaidee Alqurashi

Graduate Theses and Dissertations

The structural, dynamical, electronic, and thermoelectric properties of rock-salt and wurtzite Cd1-xZnxO alloys, VTiRhZ (Al, Ga, In, Si, Ge, Sn) and ZrTiRhZ (Ge, Sn) quaternary Heusler alloys (QHAs) were investigated using density functional theory (DFT) and semi-classical Boltzmann transport theory. From these calculations, the alloys were identified as potential materials for future thermoelectric applications. Furthermore, the magnetic and spin-polarization properties of these QHAs were investigated. The total magnetic moments were found to be integer values for all QHAs. In addition, all studied QHAs except VTiRhAl possess a half-metallic behavior with a 100% spin-polarization. The half-metallic ferromagnetic behavior makes them promising …

The Effects Of Side-Channel Attacks On Post-Quantum Cryptography: Influencing Frodokem Key Generation Using The Rowhammer Exploit, Michael Jacob Fahr

Graduate Theses and Dissertations

Modern cryptographic algorithms such as AES and RSA are effectively used for securing data transmission. However, advancements in quantum computing pose a threat to modern cryptography algorithms due to the potential of solving hard mathematical problems faster than conventional computers. Thus, to prepare for quantum computing, NIST has started a competition to standardize quantum-resistant public-key cryptography algorithms. These algorithms are evaluated for strong theoretical security and run-time performance. NIST is in the third round of the competition, and the focus has shifted to analyzing the vulnerabilities to side-channel attacks. One algorithm that has gained notice is the Round 3 alternate …

Is Artificial Intelligence A Double-Edged Sword? Insights From Three Essays On Its Impacts, Ankur Arora

Graduate Theses and Dissertations

"If we do it right, we might be able to evolve a form of work that taps into our uniquely human capabilities and restores our humanity. The ultimate paradox is that this technology may become a powerful catalyst that we need to reclaim our humanity." - John Hagel

Artificial intelligence (AI) is viewed as a disruptive technology that some executives believe will take over a lot of jobs. However, others believe that AI will bolster growth, improve business processes, and create new business opportunities. This dissertation focuses on the tension arising from such contrasting expected impacts of AI. Extant research …

Wind Tunnel Modeling Of Jack Rabbit Ii Mock Urban Environment Gas Concentration Measurements, Sami S. Fares

Graduate Theses and Dissertations

The 2015 Jack Rabbit (JR) II field trials were conducted to improve understanding of the denser-than-air dispersion of chlorine in an urban environment. The field study involved five large-scale, outdoor release trials of chlorine in a mock urban environment (MUE) at Dugway Proving Ground (DPG). Various instrumentation was deployed, including JazTM Ultraviolet-Visible (UV-Vis) point sensors capable of measuring gas-phase chlorine concentration throughout the mock urban array.

The Chemical Hazards Research Center (CHRC) was tasked by the Chemical Security Analysis Center (CSAC) with the Mock Urban Wind Tunnel (MUWT) program to study the 2015 JR II Trials at wind tunnel scale. …

An Innocent Bystander Walks Into A Bar: The Influence Of Temporal Proximity And Familiarity On Unconscious Transference, Nia Gipson

Graduate Theses and Dissertations

According to The Innocence Project, 69% of DNA exonerations in the United States involved mistaken eyewitness identification as a contributing factor to these errant convictions. Psychologists have contributed towards minimizing mistaken identifications by proposing best practices that law enforcement still follow today. One understudied cause of mistaken eyewitness identification is unconscious transference (UT). UT is a memory error in which a person encountered in an innocent context becomes confused with a person seen in a guilty context (Loftus, 1976). Past research has established some boundary conditions for when UT can occur; however, the limited methodology has resulted in narrow conclusions …

The Effects Of Consumer Loan Application Formats And Advertised Terms On Consumer Borrowing Decisions, Alicia M. Johnson

Graduate Theses and Dissertations

Consumers continue to demonstrate a willingness to accrue more debt. They are also more accepting of increased repayment risk via the acceptance of longer loan terms. Extant research on consumer borrowing consists primarily of experiments designed to assess consumer choices and understand how consumers evaluate loan attributes in relation to one another within consumer borrowing contexts (Kamleitner, Hoelzl, and Kirchler 2012; Ranyard et al., 2006). Thus, prior research examines consumer responses to loan information rather than the generation of loan parameters at the time of financing. With important implications for consumers, marketers of financial products, academic researchers, and federal regulators, …

Collaborating With Big Brothers Big Sisters And Parents To Develop Caregiver-Initiated Mentoring, Meredith J. Scafe

Graduate Theses and Dissertations

Research shows that youth enrolled in formal mentoring programs often wait months before being matched with a mentor. This paper describes the development and pilot test of Caregiver-Initiated Mentoring (CG-IM), a program originally designed to equip caregivers to assist Big Brothers Big Sisters (BBBS) mentoring program staff in identifying and recruiting mentors from their social network. Using a mixed-methods design, the initial efficacy of the CG-IM program was evaluated via a small pilot test. I broadly explored caregivers’ experiences participating in the CG-IM program and a BBBS staff member’s experience implementing it. Caregivers completed a post-survey that included quantitative measures …

Evaluation Of Single Phase Smart Pv Inverter Functions In Unbalanced Residential Distribution Systems, Darren Symonette

Graduate Theses and Dissertations

In the United States, smart PV inverters integrated with residential distribution systems are becoming a more common occurrence. With integration of smart PV inverters, power utilities are experiencing an increase of number of operations with regards to switched capacitor banks, voltage regulators and on load tap changers. These increases can lead to excess wear and tear on the devices causing power utilities to perform unwanted replacement and maintenance. However, smart PV inverters when controlled under specific functions can enable these inverters to provide reactive power and voltage control which in turn lowers the number of operations for switched capacitor banks, …

Riverscape Community Genomics Of Ozark Fishes: A Comparative Framework To Infer Ecological And Evolutionary Determinants Of Genetic Diversity, Zachery D. Zbinden

Graduate Theses and Dissertations

Genetic variation is a crucial component of biodiversity and represents the variability and spatial structure of alleles within and among organisms. Evolution modulates this variability over time through mutation, selection, gene flow, and genetic drift. However, our capacity to test foundational theories of population genetics has always been at the mercy of molecular approaches available to quantify patterns of genetic diversity. Initially, techniques for empirical DNA studies were in their infancy and limited by technologies and the price per unit of genetic information. Because of these constraints, our pursuits have generally been limited to investigations of one or a few …

Full Disclosure: Model Uncertainty In Adjusting For Confounders, Dieudonne Dusenge

Graduate Theses and Dissertations

This study examines the role of knowledge about underlying causal relationships in classifying controls in order to mitigate omitted- and included-variable biases. Using simulations and accounting examples, the study shows that the researcher may not distinguish good and bad controls because the underlying causal relationships are unobservable, and remedying strategies (such as the relative timing of measurement) may not remove the uncertainty in the classification. Because of the uncertainty about which controls to use, two or more models will be credible as will the distinct estimates derived from them. Next, the study shows that the current standard practice of singling …

Hiding In Plain Sight: Accounting For Rate Heterogeneity In Trait Evolution Models, James Boyko

Graduate Theses and Dissertations

Within the last four decades, phylogenetic comparative methods have become the defacto method of analysis for comparative biologists. The availability of high-quality comparative datasets has been matched by an explosion of possible phylogenetic models. In large part, the efforts to increase the realism of phylogenetic comparative methods has been successful as evidenced by their widespread use. To this extensive literature, my contributions are modest. I have focused my dissertation work on two main themes. First, most phenotypic evolution is not independent of other phenotypes. Changes in a particular character may influence changes in another and modeling these characters in isolation …

Media Ideologies And The Politics Of Digital Literacy: Discourses On Technology And Media In A Small School District In The U.S. Heartland, Chris Borntrager

Graduate Theses and Dissertations

This dissertation uses a discourse studies approach to investigate key communicative processes by which digital technology is given situated meanings within the institution of public education, including at the level of official discourse, administrative texts, and the spoken discourse of professional educators. The discursive processes under analysis, referred to here as “institutional media ideologies,” arguably function as discursive frameworks which, akin to tactics of management in organizations, constrain the further production of discourse in a particular professional domain, including through the codification of contextualization practices, participant roles, and the social meanings of practices implicating the use of digital technology. Furthermore, …

The Marianna Boycott: Healthcare, Political Organization, And Federal Intervention In The Arkansas Delta, Stephen James Franklin Iii

Graduate Theses and Dissertations

The Marianna Boycott was a thirteen month long civil rights boycott that took place in the Arkansas Delta town of Marianna from 1971 to 1972. The event shut down over twenty-five business, inflicted millions of dollars in economic damage, and forced people living in Lee County to address racial tensions that had been building for decades. This paper examines the Marianna Boycott as an expression of post-Civil Rights Movement conflict over what the various legislative victories of the 1960s meant for Black people in the rural south. This paper posits that while the Civil Rights laws of the era were …

Evaluation Of Carbon Isotopic Chemostratigraphy Of The Cedar Mountain Formation Of Utah, Clayton Forster

Graduate Theses and Dissertations

The Lower Cretaceous rocks of Utah preserve the origin of a multitude of dinosaur taxa, spread of angiosperms on the North American continent, and evolution of marsupial and eutherian mammals. However, the timing of deposition of these rocks is not well understood and must be determined to understand climatic controls on these biological events. Estimates of the age of the Cedar Mountain Formation and its constituent members range from Late Jurassic to early Late Cretaceous. Understanding the timing of deposition of the Cedar Mountain Formation is critical to dinosaurian and associated taxa studies as well as paleoclimate reconstructions from within …

Three Chapters On Investments And Financial Institutions, Cao Fang

Graduate Theses and Dissertations

Only the stock selection (“alpha”) decisions of fund managers who trade on firm-specific information should have predictive return content. Faced with the same information, skilled fund managers make similar stock selection decisions. In Chapter one, we introduce a new measure - stock investment quality - which uses fund quality to weight asymmetries in private information reflected in deviations of fund from peer group ownership on stocks in a style segment. We show stocks ranked high on investment quality generate significantly higher excess returns that persist through the ensuing year. The positive investment quality–future return relationship is robust to alternative fund …

Scheduling, Complexity, And Solution Methods For Space Robot On-Orbit Servicing, Susan E. Sorenson

Graduate Theses and Dissertations

This research proposes problems, models, and solutions for the scheduling of space robot on-orbit servicing. We present the Multi-Orbit Routing and Scheduling of Refuellable On-Orbit Servicing Space Robots problem which considers on-orbit servicing across multiple orbits with moving tasks and moving refuelling depots. We formulate a mixed integer linear program model to optimize the routing and scheduling of robot servicers to accomplish on-orbit servicing tasks. We develop and demonstrate flexible algorithms for the creation of the model parameters and associated data sets. Our first algorithm creates the network arcs using orbital mechanics. We have also created a novel way to …