Digital Commons Network^™

Near-Surface Soil Chemical Properties As Affected By Cover Crops Over Time In The Lower Mississippi River Valley, Cooper Fanning, Kristofor R. Brye, Michael B. Daniels, Trenton Roberts, Samuel B. Fernandes, Lisa Wood

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Typical row-crop agricultural practices can potentially be harmful to soil health and future sustainability. The use of cover crops (CC) as a mechanism to improve soil health on a wide scale remains underutilized. Soil health remains a major concern for the sustainability of agricultural productivity, therefore, research into CC implementation as a mean to preserve or improve soil health is warranted. The objective of this study was to evaluate the effects of CC on the soils in the eastern Arkansas portion of the Lower Mississippi River Valley (LMRV) over time for various chemical soil parameters, including pH, soil organic matter …

Michael Mcgraw: Profile Of The Newest Chbc Faculty Member, Danna Jaimes-Fajardo, Jeremy J. Smith, Lutishoor Salisbury

University Libraries Faculty Publications and Presentations

Presents the research profile of Michael McGraw, Assistant Professor, Chemistry and Biochemistry department. It highlights his research interests, education, and impact of his research.

First-Principles Simulation Of The Interaction Between Dna Nucleotides And One-Dimensional Carbon Chain In Electrical Based Sequencing, Zeina Salman, Jin-Woo Kim, Steve Tung

Biological and Agricultural Engineering Faculty Publications and Presentations

Electrical DNA sequencing has attracted significant attention in recent years due to its simplified sequencing protocol, compact sequencing system, and relatively low sequencing cost. In the design and fabrication of the sequencing device, carbon-based nanomaterials such as graphene have been explored as a promising sensing material that provides an excellent combination of spatial resolution and base specificity. Using first-principles simulation, we determined the effect on the electrical conductivity of a one-dimensional carbon chain due to the presence of four DNA bases. The simulation results indicate that the interaction between the carbon chain and different DNA bases leads to different levels …

Development Of Tissue-Engineered Model Of Fibrotic Scarring After Spinal Cord Injury To Study Astrocyte Activation And Neurite Outgrowth In Vitro, Nikolas Ala-Kokko, Inha Baek, Younghye Song

Biomedical Engineering Faculty Publications and Presentations

Traumatic spinal cord injuries (SCI) are debilitating injuries affecting twenty-seven million people worldwide and cause functional impairments. Despite decades of research and medical advancements, current treatment options for SCI remain limited, in part due to the complex pathophysiology of spinal cord lesions including cellular transformation and extracellular matrix (ECM) remodeling. Recent studies have increased focus on fibrotic scarring after SCI, and yet much remains unclear about the impact of fibrotic scarring on SCI lesion progression. Here, using collagen and decellularized spinal cord-based composite hydrogels, a three-dimensional (3D) cell culture model mimicking the fibrous core of spinal cord lesions was implemented …

Modern Building Structures Are A Landscape-Level Driver Of Bat–Human Exposure Risk In Kenya, Tamika Lunn, Reilly T. Jackson, Paul W. Webala, Joseph G. Ogola, Kristian M. Forbes

Biological Sciences Faculty Publications and Presentations

Identifying the locations and drivers of high-risk interfaces between humans and wildlife is crucial for managing zoonotic disease risk. We suggest that continent-wide improvements to residential housing in Africa are inadvertently creating artificial roosting habitat for synanthropic free-tailed bats (family Molossidae), and that improved buildings are a rapidly accelerating exposure interface that needs urgent research attention and investment. Along a residential gradient in rural southern Kenya, we mapped building use by free-tailed bats in 1109 buildings. We show that bats often roost in human-occupied buildings, with almost one-in-ten buildings exhibiting evidence of bat occupation (9.2%) and one-in-13 found to contain …

Balancing Ecology And Practicality To Rank Waterbodies For Preventative Invasive Species Management, Caleb P. Roberts, William E. Grant, Matthew L. Horton, Lindsey A.P. Labrie, Miranda R. Peterson, Jane S. Rogosh, Hsiao-Hsuan Wang

Biological Sciences Faculty Publications and Presentations

• ‘Early detection and rapid response’ (EDRR) is the most successful framework for preventative invasive species management, but prioritizing localized EDRR actions with limited resources is challenging. An approach that ranks individual locations, such as waterbodies, for EDRR by combining an invasive species' establishment risk with the practicality of managing it could help set reasonable priorities.
• Here, we worked with regional practitioners in Arkansas, USA, and the broader Southeastern USA to co-produce a workflow for preventative aquatic invasive species management that (1) estimates establishment risk under current and future climates with a species distribution model, (2) scores waterbodies according to difficulty …

The Effects Of Online Chemistry-Themed Design-Based Stem Education On Preservice Science Teachers’ Stem Awareness, Emine Sahin Topalcengiz, Burcin Acar-Sesen

Curriculum and Instruction Faculty Publications and Presentations

The study investigated the impact of Chemistry-Focused Online Science, Technology, Engineering, and Mathematics (STEM) teacher education on the awareness of STEM among preservice science teachers. A one-group pretest–posttest quasi-experimental weak design was used to determine changes in preservice teachers’ STEM awareness. During the study, a 14-week Chemistry-Focused Online STEM course was provided to preservice science teachers. As part of this course, the theoretical knowledge about STEM was explained to students, and afterward, they completed two modules. Furthermore, preservice teachers also developed their chemistry-themed STEM lesson plans at the beginning of the course, after explaining theoretical knowledge about STEM at the …

Meta-Analytical Evidence For Frequency-Dependent Selection Across The Tree Of Life, Miguel Gomez-Llano, Ronald D. Bassar, Erik I. Svensson, Simon P. Tye, Adam M. Siepielski

Biological Sciences Faculty Publications and Presentations

Explaining the maintenance of genetic variation in fitness-related traits within populations is a fundamental challenge in ecology and evolutionary biology. Frequency-dependent selection (FDS) is one mechanism that can maintain such variation, especially when selection favours rare variants (negative FDS). However, our general knowledge about the occurrence of FDS, its strength and direction remain fragmented, limiting general inferences about this important evolutionary process. We systematically reviewed the published literature on FDS and assembled a database of 747 effect sizes from 101 studies to analyse the occurrence, strength, and direction of FDS, and the factors that could explain heterogeneity in FDS. Using …

Stimuli-Responsive Phosphate Hydrogel: A Study On Swelling Behavior, Mechanical Properties, And Application In Expansion Microscopy, Yokly Leng, Collin N. Britten, Fatema Tarannum, Kayla Foley, Christopher Billings, Yingtao Liu, Keisha B. Walters

Chemical Engineering Faculty Publications and Presentations

Phosphorus-based stimuli-responsive hydrogels have potential in a wide range of applications due to their ionizable phosphorus groups, biocompatibility, and tunable swelling capacity utilizing hydrogel design parameters and external stimuli. In this study, poly(2-methacryloyloxyethyl phosphate) (PMOEP) hydrogels were synthesized via aqueous activators regenerated by electron transfer atomic transfer radical polymerization using ascorbic acid as the reducing agent. Swelling and deswelling behaviors of PMOEP hydrogels were examined in different salt solutions, pH conditions, and temperatures. The degree of swelling in salt solutions followed CaCl₂ < MgCl₂ < KCl < NaCl with a decrease in swelling rate at higher concentrations until reaching a saturation point. In water, the degree of swelling increased significantly around neutral pH and remained constant at basic pH values. The effects of polymerization conditions, including pH, temperature (30, 40, 50 °C), and MOEP concentration (40, 50, 60% v/v MOEP/H₂O), on the hydrogel swelling behavior in various salt solutions were also investigated. PMOEP hydrogels …

Diseases Of Cannabis Sativa And The Epidemiology And Molecular Diversity Of Neofusicoccum Parvum, Hannah V. Zima

Graduate Theses and Dissertations

Cannabis sativa has been an underutilized agricultural resource in the United States, largely due to federal regulations distinguishing marijuana from hemp. In 2018, Congress passed a Farm Bill, which defined hemp as C. sativa containing a tetrahydrocannabinol (THC) level of no more than 0.3%. As a result, commercial hemp production began in most states in 2019, including Arkansas, and was accompanied by numerous challenges like diseases and pests. The research on the epidemiology of diseases affecting C. sativa is limited, and understanding the pathogens is in its early stages in the U.S. For this study, an initial disease survey was …

Detection Of Fungicide Resistance In Population Of Corynespora Cassiicola From Arkansas Soybean And Cotton Fields, Rafael Zaia

Graduate Theses and Dissertations

Target spot, caused by the fungus Corynespora cassiicola, has reemerged since 2016 as an economically important disease on soybean and cotton across the Southern U.S. The quinone outside inhibitors (QoI) and succinate dehydrogenase inhibitors (SDHI) are important fungicide classes used to control foliar diseases in soybean and cotton. The efficacy of these products is rapidly decreasing, impacting control, and causing significant yield losses. The overall objective of this study was to determine the risks associated with chemical control by screening fungicide sensitivity, evaluating target site alterations, and analysis of disease control efficacy and yield response of fungicides for soybean in …

Interactive Effects Between Bluetongue Virus Infection And Insecticide Exposures In Culicoides Sonorensis, Parker Mullins

Graduate Theses and Dissertations

Culicoides biting midges are common pests around the world of humans, livestock, and wildlife. In addition to nuisance blood feeding, they are also able to transmit pathogens to their hosts like bluetongue virus (BTV) and African horse sickness virus, which can be damaging in terms of both production economics and animal welfare. In order to protect humans and livestock from biting pests like Culicoides, a wide array of interventions is recommended, but chemical insecticides and repellent use are ubiquitous. For a multitude of reasons ranging from natural weathering of applied insecticides to the increase in resistance-associated mutations and behaviors in …

Impact Of Equipment Type On Measured Particle Size Of Civil Engineering Materials, Tanner Turben

Graduate Theses and Dissertations

Particle size analysis (PSA) captures the size distribution of fine-grained or emulsified materials with particles generally smaller than 1000 microns. Asphalt emulsions and many other civil engineering materials do not leverage PSA for material specifications or acceptance despite the insight into material performance and quality gained through understanding the particle size. The objectives of this study are to compare PSA measurement principles by testing 13 civil engineering materials by laser diffraction, Coulter counter, and microscopy and to develop a draft standard procedure for asphalt emulsion PSA. Asphalt emulsions, cementitious materials, sands, clays, and biological samples were selected to represent a …

Fungal Pathogen Control And Microbial Ecology: Insights From Soybean Seed Production, Samantha Rigo Segalin

Graduate Theses and Dissertations

This study evaluated the effects of planting date (PD), seed vigor, and chemical seed treatments on the plant stand and yield of two soybean cultivars with different maturity groups (MGs) across four locations in Arkansas from 2018 to 2021. Early planting in early May (early PD) led to higher plant stands and yields compared to late planting in early June (late PD). The interaction between planting date and cultivar was significant, with both cultivars showing higher plant stands on early planting dates. Seed vigor and seed treatment also significantly impacted plant populations; high-vigor seeds planted early resulted in better stands …

Letters To Whiteness: Reflections On A White Artist-Educator Identity Through Dialectical Materialism, Richard Peterson

Graduate Theses and Dissertations

In this thesis, I reflect on my identity and experience as a white male and an artisteducator through a lens of critical whiteness and dialectical materialism. I utilize creative writing, and storytelling to speak more metaphorically about my own experiences and feelings in relation to whiteness to understand how I now operate as an artist-educator. Through dialectical materialism, I break down the social change described within the stories of growing up in the United States and intergenerational relationships with other white male figures, displaying more intricate ways I understand how similarities and differences change over time within the white identity …

White Guilt: An Ameliorative Proposal, William Moix

Graduate Theses and Dissertations

Common in the philosophy of race literature – notably those centered on critiques of whiteness and the oppressive structures therein – we find that guilt is looked upon rather divisively. On one hand, representative of what I call the “abolitionist” position, we find that such states serve no function but to stifle progress towards social justice. Feeling such emotions in relation to one's race seems to lead necessarily to a retreat from the social endeavor of racial justice, resulting in selfish requests for absolution. On the other hand, representative of what I call the “proponent” position, we find prescriptions to …

Breaking The Silence: Exploring The Impact Of Supervisor Vulnerability On Menstrual Disclosures At Work, Marilla Hayman

Graduate Theses and Dissertations

Management research has traditionally overlooked the significance of the human body in the workplace. However, recent recognition of organizational body work has prompted the examination of biological processes such as pregnancy and breastfeeding. Menstruation, however, has received little attention, despite the challenges faced by menstruating employees. The invisibility and silence around menstruation at work hinders managers' understanding of employee needs and prevents employees from accessing needed accommodations. An important first step in remedying this problem is understanding the factors influencing employees to disclose their menstrual symptoms and seek support. Bringing together theories of organizational body work and concealable stigmas, this …

Influence Of Invasive Species, Drought, And Stream Permanence On Stream Crayfish Species With A Focus On The Imperiled Mammoth Spring Crayfish (Faxonius Marchandi), Leah Marie Bayer

Graduate Theses and Dissertations

Freshwater crayfish constitute one of the most-threatened taxonomic groups in North America. Invasion by other crayfish species as well as habitat degradation through alteration of natural flow regime are two of the most prominent threats to crayfish persistence. Additionally, extreme weather events like droughts can amplify threats posed by other stressors on crayfish populations and are expected to increase in frequency, magnitude, and/or duration in the future, which may negatively influence narrow-ranged endemic crayfish populations typical of the Southeast. The Mammoth Spring Crayfish, Faxonius marchandi, is a narrow-ranged endemic that occurs in the Spring River drainage of Arkansas and Missouri …

Understanding The Emergence Of Self-Determination In Children With Disabilities Through Family Experiences In Early Childhood: A Qualitative Study, Karen K. Lange

Graduate Theses and Dissertations

Abstract A person’s ability to be self-determined begins to develop through the earliest interactions in life within the context of the family and caregiving environments. This qualitative phenomenological study of the experiences of eight parents representing seven families of young children explored how families promote their children’s early development of the skills, abilities, and attitudes of self-determination. The critical importance of the family context for the promotion of self-determination in young children is seen in the four themes that emerged from the experiences shared by these families. (1) The family context is transformed by a child with a disability, changing …

Investigation Of Optically Pumped Gesn Quantum Well Lasers, Grey Steven Abernathy

Graduate Theses and Dissertations

Silicon photonic integrated circuits enable the capability of producing on-chip processing of photonic signals, including both emission and detection. Emission materials, however, have been limited for monolithic integration due to high processing temperatures, indirect bandgap materials, and material integration complications. The (Si)GeSn material system has recently attracted attention due to the bandgap transition from the Si and Ge, naturally indirect bandgap, to direct bandgap with sufficient Sn incorporation. Additionally, the low growth temperature (CMOS compatible; <400 >°C) of (Si)GeSn materials can enable the monolithic integration of the highly desired mid-infrared light emission on the Si Photonic platform. This dissertation first discusses …

Synthesis Of Nanoparticles And Their Applications In Power Module Packaging And Organic Electronics, Xinsong Zhang

Graduate Theses and Dissertations

Nanoparticles can greatly change the properties of regular materials due to their special structures. In this research nanoparticles, such as silver nanowires, silver nanospheres and expanded graphite, are used in interconnection materials for power module packaging, and in conductive films for organic electronics. Silver nanowires synthesized by polyol synthesis, are used as fillers in micron silver paste. The electrical and mechanical properties of the sintered hybrid silver paste are investigated and compared with those of micron silver paste. The composites of silver nanospheres and expanded graphite are mixed with PEDOT:PSS solutions in 5 different weight ratio. The electrical and optical …

Investigating The Applications Of Peps To The Measurement Of The Stabilities Of Staphylococcal Nuclease (Stw) And Human Acidic Fibroblast Growth Factor (Hfgf1), Motolani Omolade Matthew

Graduate Theses and Dissertations

This dissertation presents a detailed investigation into the applications of Protein Equilibrium Population Snapshot H/D Exchange Electrospray Ionization Mass Spectrometry (PEPS-H/D exchange or PEPS) method. This method is based on protein equilibrium unfolding, and its fundamental capability is to capture a "snapshot" of the protein's state, allowing us to monitor the ratio of the unfolded to folded populations at different chemical denaturant concentrations. First, to increase the accuracy of PEPS data analysis for assessing protein stability, the traditional linear extrapolation method (LEM) was replaced. Instead of using LEM, which calculates free energy change based on the peak ratio of unfolded …

Parallel Degree Planning In The Pursuit Of Academic Success For Pre-Nursing Students In A Competitive Entry Baccalaureate Nursing Programs, Elizabeth L. Mckinley

Graduate Theses and Dissertations

This study sought to understand the student perceptions of parallel academic degree planning for the competitive entry undergraduate Nursing program at a case study university. Parallel degree planning is a relatively new term of alternative curricular planning. The qualitative study includes nine students and their experiences in planning for their intended major while simultaneously planning courses that meet another major or degree program, and understanding how parallel degree planning aided their retention and student satisfaction as well as their academic advisor interaction. The study was completed at a research university where the Nursing program has a very lower acceptance rate, …

Development Of A High-Throughput Screening Platform To Profile Gene Delivery And Transcriptional Control In Macrophages, Alexis Ivy

Graduate Theses and Dissertations

Macrophages are an important cell type in the body responsible for orchestrating the inflammatory response and return to homeostasis. Macrophages are often implicated in a multitude of disease pathologies including delayed wound healing, excessive fibrosis, autoimmune disease, and immunosuppression within the tumor microenvironment. Although macrophages have been targeted for therapeutic applications, success in utilizing them has remained elusive due to their relative ease of phenotype switching between inflammatory and anti-inflammatory. The challenge that remains is developing clinically relevant delivery vehicles that can target macrophages without causing a phenotypic switch counter-productive to the desired response. This is especially important when targeting …

Investigating The Detection And Transport Of Low Molecular Weight Species To Better Understand Their Impact On Disease Pathology And Treatment, Haley Michelle Duncan

Graduate Theses and Dissertations

Due to the drastic differences in the projects involved, this dissertation will be split into two sections: Alzheimer’s disease and chronic kidney disease. Each chapter will contain an introduction, materials and methods section, results and discussion, conclusions, and works cited section. The Alzheimer’s disease chapter will also have a supplemental figures section containing the polyacrylamide gels that were silver stained and quantified via ImageJ. The presence of elevated levels of amyloid beta oligomeric species in the brain has been related to the pathology of Alzheimer’s disease. As these oligomeric species are transient in nature, their kinetics pose a challenge to …

Neural Interactions In Bottom-Up Communication, Prashant Chama Raju

Graduate Theses and Dissertations

The visual system’s remarkable ability to process vast amounts of sensory information rapidly and accurately is fundamental to cognitive neuroscience. This study investigates a key aspect of this capability: the compartmentalization of information into feature-specific subspaces during bottom-up communication. My primary question was: does Canonical Correlation Analysis (CCA) reveal a subspace that encodes color and direction of moving dot stimuli? I found that the first canonical component (CC1) does an excellent job decoding the stimuli, despite being one-dimensional while the stimuli were drawn from a two-dimensional space (red-green and up-down plane). I demonstrate that motion features are processed within distinct …

Quantifying Physical Function: Moving Towards A New Definition And Better Assessment, Anthony Campitelli

Graduate Theses and Dissertations

Though poor physical function (PF) and disability are two of the most impactful problems facing older adults today, the field of kinesiology has not yet devised a method of measuring PF, thus limiting investigations with the potential to lead to improved PF interventions and assessments. This dissertation aimed to develop a single, continuous measure of PF using a latent variable modeling approach, and then use the generated scores to evaluate the role of lower body muscular power in PF assessment and to construct an improved PF assessment battery for predicting overall PF. Each aim of this dissertation was addressed through …

Phylogenomic Analyses Of Three Distinct Lineages Uniting Staphylococcus Cohnii Snd Staphylococcus Urealyticus From Diverse Hosts, L. Caroline House, Amer Hasan, Andi Asnayanti, Adnan A. Alrubaye, Jeff Pummill, Douglas Rhoads

Poultry Science Faculty Publications and Presentations

We sequenced and assembled genomes for 17 isolates of Staphylococcus cohnii isolated from osteomyelitis lesions in young broilers from two separate experiments where we induced lameness using a hybrid wire-litter flooring system. Whole genome comparisons using three different methods support a close relationship of genomes from both S. cohnii and Staphylococcus urealyticus. The data support three different lineages, which we designated as Lineage 1, Lineage 2, and Lineage 3, uniting these two species within an evolving complex. We present evidence for horizontal transfer between lineages of genomic regions from 50–440 kbp. The transfer of a 186 kbp region from …

How Local Interactions Give Rise To Large-Scale Conformational Changes In Proteins: A Molecular Dynamics Study, Shadi A. Badiee

Graduate Theses and Dissertations

Proteins are dynamic entities that undergo conformational changes essential for their biological functions. These structural changes often correspond with chemical events such as lipid interactions or environmental changes like protonation or acidification. Understanding the complex relationship between these chemical perturbations and the resultant mechanical responses is crucial for elucidating protein mechanisms. This dissertation investigates the chemo-mechanical coupling in the conformational dynamics of the bacterial ABC transporter Sav1866 and the impact of protonation on the Influenza virus hemagglutinin HA0. Using molecular dynamics simulations, we explore the conformational landscapes of Sav1866 and HA0. Our study examines how varying lipid compositions affect the …

Struvite Effects On Greenhouse Gas Emissions From Flood- And Furrow-Irrigated Rice In The Greenhouse, Chandler Arel

Graduate Theses and Dissertations

Over time, as the influences of climate-change and declining, mineable, global phosphorus (P) reserves begin to impact agricultural production systems, alternative fertilizer sources and management practices, such as struvite (MgNH₄PO₄ · 6H₂O) and furrow-irrigation, will be necessary to accommodate nutrient and water demands. The precipitation and use of struvite as a fertilizer-P source could reduce environmental damages caused by nutrient-rich wastewater streams, supplement domestic P supply, and improve the sustainability of flood-, and furrow-irrigated rice production by reducing greenhouse gas emissions. The study of struvite from both chemical and electrochemical precipitation processes is well documented, …