Digital Commons Network^™

Delineating Field Variation Using Apparent Electrical Conductivity In An Ozark Highlands Agroforestry System, Shane Reid Ylagan

Graduate Theses and Dissertations

Little to no work has been conducted assessing field variability using repeated electromagnetic induction (EMI) apparent electrical conductivity (ECa) surveys in agroforestry (AF) systems within regions similar to the Ozark Highlands. The objectives of this thesis were to identify i) spatiotemporal ECa variability; ii) ECa-derived soil management zones (SMZs); iii) correlations among EMI-ECa and in-situ, sentential-site soil properties; iv) whether fewer, EMI-ECa surveys could be conducted to capture similar ECa variance as mid-monthly EMI-ECa surveys; v) correlations between ECa and forage yield, tree growth, and terrain attributes based on plant (forage and tree) species, and fertility treatments, and ECa-derived SMZs, …

Visible Light-Assisted Deconstruction/Refunctionalization Of Strained And Unstrained N-Cycloalkylanilines, Elvis Duah Boateng

Graduate Theses and Dissertations

The exploitation of ring strain as a driving force to facilitate chemical reactions is a well-appreciated principle in organic chemistry. Of the strained carbocycles frequently explored in this respect, cyclopropane ring systems have drawn considerably more interest among synthetic chemists than their homolog, the cyclobutane ring systems, even though the strain energy of cyclobutane (26.7 kcal/mol) is similar to that of cyclopropane (27.5 kcal/mol). We have previously developed a [4+2] annulation reaction for the synthesis of aniline-substituted six-membered carbocycles under photoredox catalysis via the oxidative cleavage of N-cyclobutylanilines. The key reaction involved in this method is a ring-opening process of …

Deciphering Surfaces Of Trans-Neptunian And Kuiper Belt Objects Using Radiative Scattering Models, Machine Learning, And Laboratory Experiments, Al Emran

Graduate Theses and Dissertations

Decoding surface-atmospheric interactions and volatile transport mechanisms on trans-Neptunian objects (TNOs) and Kuiper Belt objects (KBOs) involves an in-depth understanding of physical and thermal properties and spatial distribution of surface constituents – nitrogen (N2), methane (CH4), carbon monoxide (CO), and water (H2O) ices. This thesis implements a combination of radiative scattering models, machine learning techniques, and laboratory experiments to investigate the uncertainties in grain size estimation of ices, the spatial distribution of surface compositions on Pluto, and the thermal properties of volatiles found on TNOs and KBOs. Radiative scattering models (Mie theory and Hapke approximations) were used to compare single …

Temporal Effects Of Acute Moderate Intensity Physical Activity On Working Memory Performance In Young Adults, Kimberly Loy Seibold

Graduate Theses and Dissertations

An ample amount of research suggests that increases in physical activity in young adults could help improve memory and cognitive functions which may aid in academic success (Johnson & Loprinzi, 2019; Perini et al., 2016). A sufficient working memory is critical to learning because it allows us to temporarily store and compare multiple informational items at one time to form a new concept or solve a problem (Cowan, 2013). The purpose of this study was to examine the temporal effects of acute moderate intensity physical activity on working memory in young adults. This study utilized a within-groups (repeated measures) cross-over …

Improving Math Placement Of Non-Traditional Students In Arkansas Community Colleges Using Multiple Measures Assessments, Johnathon Edward Paape

Graduate Theses and Dissertations

For decades, community colleges have relied on standardized placement tests to determine student readiness for college-level coursework. COVID-19 exposed the flaws of relying on a single measure to assess student readiness as many test sites shut down during the pandemic. Previous research has also pointed out the high rate of misplacement when using placement tests as a single factor. This is particularly important for non-traditional students as they often lack the guidance needed to successfully navigate and prepare for such tests. The result of this situation is often that non-traditional students are placed into remedial courses despite having the potential …

Perceptions Of Beginning Secondary Alternatively Licensed Family And Consumer Sciences Teachers In Kansas: A Case Study, Jennifer S. Snell

Graduate Theses and Dissertations

Alternatively licensed Career and Technical Education teacher licensure programs have become a more conventional process for licensing new CTE teachers. Evidence from recent research supports that alternatively licensed teachers have a much greater teacher turnover rate than traditionally licensed teachers. This study focused on Family and Consumer Sciences education, which is part of the umbrella of CTE. There is limited research on new teacher training that specifically supports beginning alternatively licensed secondary FCS teachers in Kansas. This qualitative study examined the experiences of novice alternatively licensed secondary FCS teachers in Kansas who transitioned from the workforce with no previous teacher …

The Effect Of Spirulina Platensis Algae Inclusion In Feed Of Commercial Broilers Subjected To Cyclic Heat Stress, Kirsten Shafer

Graduate Theses and Dissertations

The effect of Spirulina platensis inclusion in feed of commercial broilers was evaluated over one experiment. The study aimed to investigate the effects of Spirulina platensis freshwater algae inclusion on live performance and processing characteristics of commercial broilers subjected to daily cyclic heat stress. Day old Ross 708 male broilers were placed into 8 environmentally controlled chambers. At d 21, four chambers remained on a control diet containing no algae (CON) while 4 chambers received a diet that included algae at an inclusion rate of 2.5% (ALG). An 8 hour daily cyclic heat stress (24°C to 36°C) was applied to …

The Binding Of The Micronutrient Transition Metals To The Alkylation Products Of Chemical Warfare Agent, Sulfur Mustard, And Thiols, Potentially Giving New Understanding To Physiological Effects Of Exposure And Increased Toxicity, Colin O'Donnell

Graduate Theses and Dissertations

Model compounds, 3,6,9-trithaiundecane-1,11-dicarboxylic acid (TTDPA), 2,5,8-trithianonane-1,9-dicarboxylic acid (TTDAA), and 1,11-diamide-3,6,9-trithiaundecane (TTDAce), closely related to the adducts formed by cysteine alkylation of the chemical weapon, sulfur mustard, were synthesized. It is shown that TTDPA forms complexes with key metal micronutrients: copper, nickel, cobalt, manganese, and zinc. Though the strength of binding to TTDPA varies, the complexes in many cases precipitate from solution. All metals produced a visible precipitate upon interaction with TTDPA under the conditions tested, however only Cu2+, Mn2+, and Zn2+ produced enough to be measured. The mass of formed precipitate seemed to peak at an equimolar ratio of TTDPA …

Machine Learning For Early Detection Of Pediatric Sepsis, Glory Manson-Endeboh

Graduate Theses and Dissertations

Sepsis is a host response to infection in both adults and children. It contributes to approximately 1.7 million cases annually with nearly 270,000 annual deaths in the United States. In the United States, the financial burden of sepsis on survivors and their families including the hospitals is over $4.8 billion, at approximately $64,280 per hospitalization. The first goal of this thesis research is to develop efficient machine learning models to predict pediatric sepsis accurately for inpatients. The second objective is to develop machine learning methods to determine how early sepsis can be detected to mitigate mortality. We examine data collected …

A Study On Interactions Between Metal-Organic Frameworks And Biological Materials, Josh Phipps

Graduate Theses and Dissertations

Metal-organic frameworks or MOFs are an extremely useful tool in many areas of applications. Their popularity in recent years has arisen from their high efficiency in catalytic chemical reactions. This is made possible due to their porous interior and the ability of the MOFs components to be functionalized. These same traits make MOFs excellent for use in protein encapsulation or immobilization and have the potential to become excellent drug carriers. Their development in this utilization has been limited dramatically compared to MOFs chemical applications. This is due in part to the nature of biological processes taking longer to study, but …

Cell Division Dynamics Of Escherichia Coli In Extreme Environments, Steven P. Murray

Graduate Theses and Dissertations

Life is remarkable in how resilient it can be. Many organism, classified as ex- tremophiles, can not only survive in extreme environments, but they can thrive in them. In the search for extraterrestrial life, the best candidates to harbor life exist with some kind of extreme condition. Europa, for example, is a favorite for the possibility of accommodating life as we know it within our solar system. Thought there is believed to be a liquid ocean under its icy surface, this habitat would be under immense pressures and high salinity. To best know where to look for extraterrestrial life, it …

Life Cycle Assessment Of Novel Electrochemical Struvite Recovery In Municipal Wastewater Treatment At The Plant And U.S. Watershed Scales, Karla Morrissey

Graduate Theses and Dissertations

As the supply of phosphorus decreases, nutrient recovery in municipal wastewater treatment has become an important area of research. Recovery methods for phosphorus-containing fertilizers, such as struvite, and other products are currently being developed and assessed for their efficiency and economic feasibility. Potential environmental impacts from nutrient recovery are also being assessed as design for the environment is important, especially with regards to the eutrophying potential of phosphorus in phosphorus-limited freshwater aquatic systems. Life cycle assessment (LCA) is a tool that can be used to estimate potential environmental impacts of a product or service focusing on its entire life cycle. …

Surface-Driven Instabilities At Oil-Water Interfaces, Anelisse Claros Mendieta

Graduate Theses and Dissertations

Fluid-fluid interactions are such a wide area and can be observed in different scenarios such as geothermal systems, waterflooding of reservoirs, oil recovery, and water treatment processes. This thesis aims to deepen the understanding of fluid-fluid interactions which include Marangoni flows, charge related instabilities, and surface activity. This thesis studied the interactions of micrometer-sized droplets of an oil (toluene) with surfactant Di-(2-ethylhexyl) phosphoric acid (DEHPA) in the aqueous phase. One of the main goals is to understand several surface-driven instabilities and how those can be manipulated for future applications.Furthermore, this thesis aims to use these oil-surfactant droplets as a medium …

Improved Compact Modeling Of High Voltage Gallium Nitride High Electron Mobility Transistors, Md Maksudul Hossain

Graduate Theses and Dissertations

Since power converters shape a wide range of power electronic applications, the 'heart' of these conversions, such as solid-state switches, is crucial for achieving higher power density, lower loss, and higher efficiency operations. Although the limitations imposed by silicon-based power devices have been reduced by introducing novel devices such as IGBTs and super junction MOSFETs to allow for broader applications, solutions beyond silicon have presented a continuous challenge to the device engineers. Driving these converters at a higher switching frequency allows for higher power density. However, to support a higher frequency and operating temperature, superior materials, e.g., wide bandgap materials, …

Mle And Eap Methods For Estimating Ability Scores For Data Of Varying Sample Size And Item Length, Sahar Taji

Graduate Theses and Dissertations

In this research, the performance of two popular estimators, Maximum Likelihood Estimator(MLE) and Bayesian Expected a Posteriori (EAP) is studied and compared in estimating the latent ability score in an Item Response Theory (IRT) model. The 2-Parameter Logistic (2PL) IRT model which is characterized by difficulty and discrimination item parameters is used to estimate the latent ability scores. Several datasets are generated for variety of sample size and item length values. The Monte-Carlo simulation is used to analyze the performance of the estimators. Results show that MLE produces reliable results with low root mean square error (RMSE) across all datasets. …

Electrical Modeling For Dynamic Performance Prediction And Optimization Of Mcpms Layout, Quang Minh Le

Graduate Theses and Dissertations

In recent years, the fast development of Multichip Power Modules (MCPM) packaging and Wide Bandgap (WBG) technology has enabled higher voltage and current ratings, better thermal performance, lower parasitic parameters, and higher mechanical reliability. However, the design of the MCPM layout is a multidisciplinary problem leading to many time-consuming analyses and tedious design processes. Because of these challenges, the design automation tool for MCPM layout has become an emerging research area and gained much attention from the power electronics community. The two critical objectives of a design automation tool for MCPM layout are fast and accurate models for design insights …

Orbital Mapping Of Seasonal And Yearly Changes In Co2 And Water Ice On The Southern Polar Cap Of Mars, Victoria Michell Ann Karnes

Graduate Theses and Dissertations

This research exhibits a new foundation for the rates of change in CO2 and water ice on the southern polar cap of Mars, where the annual precipitation cycles are known to fluctuate seasonally between the north and south pole, based on observations from the Compact Reconnaissance Imaging Spectrometer (CRISM). The conventional belief is that both CO2 ice and water ice on the southern polar cap condenses and evaporates over the course of a Martian year (MY), condensing during the Martian spring and summer and evaporating during the Martian fall and winter. With this theory in mind, CO2 and water ice …

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 …

The Relationship Between Grit, Perceived Social Support, And Educational Gains In The Adult Basic Education Classroom, Jennifer D. Shearon

Graduate Theses and Dissertations

Adult Basic Education (ABE) is a critical part of the educational landscape in the United States; its aim is to improve the basic reading, writing, and numeracy skills of the very diverse population of adults in America who lack proficiency in these skills, and more often than not, a high school graduation credential (U.S. Department of Education, 2021a). Each program year, federal funding for ABE state administrated programs under the Workforce Innovation and Opportunity Act (WIOA, 2014) is tied to percentages of participants who make measurable skills gains (MSGs). One type of MSG is Educational Functioning Level (EFL) gains, which …

Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer

Graduate Theses and Dissertations

Proper nitrogen (N) management in rice production can be difficult to achieve without the aid of tools such as soil and tissue tests. There are no tests currently available to rice producers that determine whether N has been managed properly throughout the season or that detect instances of over fertilization. Rice stalk samples were collected from N response trials within 3 days of harvest from the primary Arkansas rice growing region in 2016-2018. Stalk samples were analyzed for N concentration through a KCl extraction and spectrofluorometric quantification. Samples analyzed with leaf material intact contained statistically different N concentrations than samples …

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.

Using Molecular Dynamics Simulations To Decipher Mechanistic Details Of Biomolecular Processes Of Biology And Biotechnology Oriented Applications, Adithya Polasa

Graduate Theses and Dissertations

Researchers in chemistry and biology often utilize computer simulations, in conjunction with experimental data, to model and predict the structures, energies, kinetics, processes, and functions of the systems that are their focus of study, ranging from single molecules to whole viruses. Here, we use molecular dynamics (MD) techniques to gain a deeper understanding of biomolecular processes in biology and biotechnology-oriented applications. Using a mixture of equilibrium and non-equilibrium MD simulations, this work describes the insertion process of YidC at the atomic level. In order to better comprehend the insertion process, several docking models of YidC-Pf3 in the lipid bilayer were …

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 …

Hypothesis Testing And Parameter Estimation In Mixture Cure Models For Cancer Survival Data, Mohammod Mahmudur Rahman

Graduate Theses and Dissertations

In oncology clinical trials, when a treatment is administered to the patient population, a certain subset of patients may respond to the treatment while the other does not. The positive responders with long-term survival are considered “statistically cured” and can be referred to as cured patients or long-term survivors. When a proportion of patients achieve long-term survival, the hazard functions of two arms (control vs. treatment) are no longer proportional. As a result, the traditional log-rank test, which is the most popular test to evaluate the effectiveness of a treatment in clinical trials, tends to lose its power. In this …

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 …

Environmental Communication: Changing The Attitude-Behavioral Gap In Science Communication Utilizing Strategic Messaging, Carrie Helgeson Nelms

Graduate Theses and Dissertations

National Polls in the United States consistently find the public’s beliefs and attitudes about climate change and other environmental issues significantly diverge from those held by the science community. A communication gap between the findings on the causes and effects of environmental issues and the public’s inability to interpret or refuse to accept these findings are possible causes of this divergence. This communication gap constitutes a threat to society because of inaction to environmental problems and points to needed changes in scientific messaging that better informs and motivates behavioral change. The present research employed a strategic message design to affect …

Analysis Of Seismicity And Related Seismic Risk In Muslim Countries: Case Studies From Afghanistan And Pakistan, Ikramuddin Bahram

Graduate Theses and Dissertations

How communities respond to a natural hazard is influenced by how they perceive it. This dissertation evaluated the gap between intent and action regarding earthquake hazards in Muslim countries with a focus on Afghanistan and Pakistan. Cultural biases provided predictions of risk perceptions and risk-taking preferences that were often more powerful than measures of knowledge and experience. In Muslim communities, perception of risk was influenced by the teachings of Islam and related rituals, traditions, and culture.

This study evaluated the seismicity and earthquake hazard in Afghanistan and Pakistan. Assessments of seismic risk and perception of danger were conducted to examine …