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Time And Chance Happen To Them All: A Macroevolutionary Examination Of The Effects Of Whole Genome Multiplications, Eric Robert Hagen

Graduate Theses and Dissertations

Polyploidy, the state of having more than two complete sets of chromosomes, is common in plants and has been linked to several beneficial traits. On the macroevolutionary scale, the effects of polyploidy have been hotly debated for over one hundred years, being alternatively described as an “evolutionary dead end” and the most important discovery in evolutionary biology since Darwin and Wallace. This thesis aims to contribute to the debate by studying the diversification, biogeography, and ecophysiology of polyploid flowering plants with recently developed phylogenetic comparative methods. This dissertation has three chapters. In Chapter I, I review work on the so-called …

A Pilot Study Of Students’ Ethical Decision Making And Emotional Intelligence, Casandra K. Cox

Graduate Theses and Dissertations

Demand for ethical leaders in agriculture is high to meet 21st century goals, while ethics course offerings in land-grant institutions are limited. The purpose of this case study was to establish a baseline of current University of Arkansas Bumpers College of Agriculture, Food and Life Science (Bumpers College) agriculture and natural resource program students’ ethical decision making (EDM), as measured by the DIT-2, and emotional intelligence (EI), as measured by STEM-B and STEU-B, determine if EI mean scores predict EDM, and identify relationships between EDM or EI and demographic characteristics or lifespan experiences. An online survey design with probability sampling …

Investigation Of Consumer Freezing Practices, Condition And Duration On Palatability Of Beef, Elizabeth Sue Neal

Graduate Theses and Dissertations

The objective of these studies was to determine: the impact of extended periods of frozen storage duration and packaging type on palatability traits of cooked beef steaks from two muscles and the impact of freezing type and storage duration on objective and subjective measures of ground beef palatability traits. In study 1, no differences were elicited from any of the possible interactions (P= 0.95) for SSF or CL: package × muscle × freezing duration, package × muscle, package × duration or muscle × duration. However, freezing duration did impact both SSF (P < 0.01) and CL (P < 0.001). Generally, for both SSF and CL steaks that were frozen for 9-months elicited both the highest SSF values as well as the greatest percentage of CL among all treatments. In comparison, EM was impacted by the interaction (P = 0.059) of packaging type  muscle  freezing duration. Samples from OW GM stored for 9-months elicited the highest percentage of EM while fresh OW LL samples resulted in the lowest. Additionally, expressible moisture was impacted by the interaction (P = 0.047) of muscle  freezing duration. Among all treatments, GM steaks that were frozen for 9-months elicited the highest EM values and fresh LL samples the lowest EM values. Contrastingly, there was no significant difference observed in expressible moisture for the interaction (P  0.18) of package type  freezing duration or for the interaction (P = 0.70) of package type  muscle. Generally, fresh OW GM steaks resulted in the greatest concentration of lipid derived volatile compounds such as aldehydes, hydrocarbons and alcohols which contrasted sensory ratings of trained panelists that indicated oxidized and refrigerator-stale ratings increased as storage time increased for OW steaks. In study 2, The interaction of freezer treatment × storage duration impacted gumminess (P = 0.05), a TPA attribute. In greater detail, samples stored in RF for 6-months resulted in the greatest gumminess values (P < 0.001), while those stored in the CF for 12-months elicited the lowest (P < 0.001). Similarly, flavor development was also impacted by the interaction (P = 0.05) of freezer treatment × storage duration. Three lipid derived compounds were of greatest concentration among RF patties stored for 1-month. In contrast, the interaction of freezer treatment × storage duration elicited no impact on consumer ratings, SF or TBARS. Nonetheless, frozen storage duration impacted TPA, flavor development, consumer ratings, SF and TBARS as a main effect (P < 0.05), especially in regard to tenderness and juiciness. Moreover, beef flavor development, tenderness and juiciness are impacted by freezing duration, muscle, freezer type and packaging, however these factors are not necessarily independent of one another. Furthermore, the retail display period is a critical period for fresh beef steaks, especially when packaged in aerobic conditions. For optimal eating experience, beef products should be stored for extended periods in a vacuum packaging, in a designated freezer that is not opened frequently to allow for optimal air flow regulation and minimize freezer burn to improve tenderness and juiciness.

The Effect Of Sleep Deprivation On The Ability To Reappraise Negative Situations, Rebecca Campbell

Graduate Theses and Dissertations

Sleep and emotion regulation are important components of mental health and may function interdependently in the development and maintenance of mental health disorders. Unfortunately, there is limited experimental work on the impacts of sleep deprivation on reappraisal, a common emotion regulation strategy, in adults. Furthermore, increases in negative and decreases in positive affect are often associated with sleep loss. This study aimed to examine the relation between sleep deprivation and emotion regulation by asking adults to reappraise a series of vignettes before and after a randomly assigned night of sleep deprivation or normal sleep. Additionally, measures of self-reported emotion regulation …

Evaluation Of Biochar Rate And Hemp Cultivar For The Phytoremediation Of Heavy-Metal-Contaminated Soil From The Tar Creek Superfund Site, Dietrich Thurston

Graduate Theses and Dissertations

Soil contamination by cadmium (Cd), lead (Pb), and zinc (Zn) at the Tar Creek Superfund site in Northeast Oklahoma remains a threat to the environment and local ecosystem. Phytoremediation by industrial hemp (Cannabis sativa L.) and the use of biochar (BC) have been independently shown to be effective methods to remediate heavy-metal-contaminated soils. The objective of this greenhouse study was to evaluate the effects of industrial hemp cultivar (‘Carmagnola’ and ‘Jinma’), BC rate (0, 2, 5, and 10% by volume), soil contamination level (low, medium, and high), and their interactions on above- and belowground (AG and BG, respectively) plant dry …

Symptom Experience Of Patients With Advanced Melanoma Undergoing Immune Checkpoint Inhibitor Therapy, Natalie Jackson-Carroll

Dissertations and Theses (Open Access)

Background: Immune checkpoint inhibitors (ICIs) are novel therapeutic agents utilized in the management of advanced melanoma. Though generally well-tolerated, patients receiving ICIs experience treatment-related toxicities at varying onset and intensity. Assessment and evaluation of these toxicities and their impact on a quality of life is essential to comprehensive cancer care. Patient-reported outcomes (PRO) contribute vital data to a clinical assessment, supporting clinicians in their ability to improve outcomes. To date, there is no melanoma-specific or ICI-specific PRO measure of symptom burden available.

Purpose: The purpose of this study was to describe the symptom experience from the patient's perspective and how …

Does Herding Behavior Exist In The Cryptocurrency Market?, Anis Mnif

Doctoral Dissertations (DBA)

This paper examines herd behavior in the cryptocurrency market using data of the top 15 large cryptocurrencies and the CCi30 Index as a proxy for market return. The idea that investors mimic and follow the behavior of others in the cryptocurrency market rather than conducting their own research has received attention in the finance literature. The CSAD results in the static model detected herding but given the existence of structural breakdowns and nonlinearities in the data series, we opted to conduct a rolling window analysis. The results indicate strong herding behavior that fluctuates over time. Furthermore, results from the logistic …

Dry-Aged Beef Flavor Development, And The Effect Of High Levels Of Vitamin-E On Beef Color Stability, Nicolas Herrera

Department of Animal Science: Dissertations, Theses, and Student Research

Palatability and consumer purchasing are essential factors of fresh meat. To meet consumer expectations during purchasing and consumption, fresh beef must maintain desirable cherry-red color at retail and achieve desirable cooked flavor. Dry-aged beef popularity has grown, and identifying methods to ensure quality dry-aged meat is necessary to maintain demand. To understand dry-aged palatability, this dissertation addressed effects of moisture loss and aging time, fundamental factors of dry-aged beef, using bone-in and boneless strip loins. Study two investigated flavor development using cookery methods and internal temperatures in boneless and bone-in dry-aged beef. In study one, increased dry-aging time (creation effect) …

Consequences Of Cow–Calf Production With Limited Perennial Forage Grazing, Hannah Fae Speer

Department of Animal Science: Dissertations, Theses, and Student Research

Conversion of perennial grasslands to cropland and rising land prices prompts a need to evaluate alternative beef cow-calf production systems. A 3-yr study was conducted comparing beef cow-calf performance between two August-calving cow systems: perennial forage and corn residue grazing; or summer drylot, fall grazing of late-summer-planted cover crop, and corn residue grazing. Cow body condition score differed between systems, but condition of cows in both systems never fell below adequate. There were no differences in pregnancy rates between systems. Calf weaning weights differed between systems each year; differences are attributed to feedstuff quantity, quality, and type available to calves …

Flow Dynamics In Cardiovascular Devices: A Comprehensive Review, Venant Niyonkuru, Bosco Jean Ndayishimiye Dr, Anicet Barthélemy Sibomana

Digital Journal of Clinical Medicine

This review explores flow dynamics in cardiovascular devices, focusing on fundamental fluid mechanics principles and normal blood flow patterns. It discusses the role of different structures in maintaining flow dynamics and the importance of stents, heart valves, artificial hearts, and ventricular assist devices in cardiovascular interventions. The review emphasizes the need for optimized designs and further research to enhance knowledge of flow dynamics in cardiovascular devices, advancing the field and improving patient care in cardiovascular interventions.

Impact Of Geographical And Demographic Factors Of Clinical/Social Preparedness, Attitudes, And Basic Knowledge Of Secondary School Counselors Regarding Services For Lgbtq+ Students, Ashley Chivon Hughley

Dissertations (2016-Present)

The purpose of this study was to examine the school counselors’ total competency of preparedness, attitudes, and basic knowledge of LGBTQ+ students across the United States. Specifically, the researcher was concerned with the predictable relationship between the school setting (middle and high school), geographical location (urban and rural), and the number of professional development training hours on the total competency (preparedness, attitudes, and basic knowledge) regarding LGBTQ+ students of school counselors. The sample consisted of 174 secondary school counselors from the American School Counselor Association (ASCA). Purposive sampling was utilized to select the population sample. Sequential Multiple Regression was used …

On The Topology Of The Noosphere, Julie A. Yusupova

Journal of Conscious Evolution

As a young child I had a certain set of dreams, the enigma of which remained mysteriously hovering in my memories to this day. In one of these earliest dreams of my life, I am playing hide-and-seek with my friends, but am observing myself from an external third-person perspective, just as all my dreams had regularly been until then. I remember that the next morning, my waking conscious mind had noticed this split between self and observer and judged it unusual, and so in the following night’s dream, I somehow willed my observer self to merge into the body of …

Utilizing Mitotalens To Investigate Large Repeats In The Arabidopsis Thaliana Mitochondrial Genome, Cambelle Johnson

Honors Program: Senior Projects (Public)

Mitochondria are a silly place to store the genetic code. In spite of the ever-present threat of oxidative DNA damage, plant mitochondrial genomes are expansive in size and include noncoding repeat sequences, a small number of which are greater than 1kilobase (kb), known hereafter as “large repeats” (LR). This theme of one or more large repeat pairs is shared across most flowering plants, lending to the belief that they somehow contribute to the plant’s fitness. These repeats exhibit high rates of rearrangement and recombination. Studying repeats in vivo could have large scale implications in hybrid crop production enhancement including eliminating …

Whole Blood Resuscitation And Association With Survival In Injured Patients With An Elevated Probability Of Mortality, Jason L Sperry, Bryan A Cotton, James F Luther, Jeremy W Cannon, Martin A Schreiber, Ernest E Moore, Nicholas Namias, Joseph P Minei, Stephen R Wisniewski, Frank X Guyette, Shock, Whole Blood, And Assessment Of Traumatic Brain Injury (Swat) Study Group

Faculty, Staff and Student Publications

BACKGROUND: Low-titer group O whole blood (LTOWB) resuscitation is becoming common in both military and civilian settings and may represent the ideal resuscitation intervention. We sought to characterize the safety and efficacy of LTOWB resuscitation relative to blood component resuscitation.

STUDY DESIGN: A prospective, multicenter, observational cohort study was performed using 7 trauma centers. Injured patients at risk of massive transfusion who required both blood transfusion and hemorrhage control procedures were enrolled. The primary outcome was 4-hour mortality. Secondary outcomes included 24-hour and 28-day mortality, achievement of hemostasis, death from exsanguination, and the incidence of unexpected survivors.

RESULTS: A total …

The Hylefm Gene In Phylefm Of Enterococcus Faecium Is Not Required In Pathogenesis Of Murine Peritonitis, Victoria H Wu, Bryan S Yung, Farhoud Faraji, Robert Saddawi-Konefka, Zhiyong Wang, Alexander T Wenzel, Miranda J Song, Meghana S Pagadala, Lauren M Clubb, Joshua Chiou, Sanju Sinha, Marin Matic, Francesco Raimondi, Thomas S Hoang, Rebecca Berdeaux, Dario A A Vignali, Ramiro Iglesias-Bartolome, Hannah Carter, Eytan Ruppin, Jill P Mesirov, J Silvio Gutkind

Faculty, Staff and Student Publications

Immune checkpoint blockade (ICB) targeting PD-1 and CTLA-4 has revolutionized cancer treatment. However, many cancers do not respond to ICB, prompting the search for additional strategies to achieve durable responses. G-protein-coupled receptors (GPCRs) are the most intensively studied drug targets but are underexplored in immuno-oncology. Here, we cross-integrated large singe-cell RNA-sequencing datasets from CD8+ T cells covering 19 distinct cancer types and identified an enrichment of Gαs-coupled GPCRs on exhausted CD8+ T cells. These include EP2, EP4, A2AR, β1AR and β2AR, all of which promote T cell dysfunction. We also developed transgenic mice expressing a chemogenetic CD8-restricted Gαs–DREADD to activate …

Biochemical Characterization Of Ssb1, Ssb2, Sycp3, And Meilb2 In Meiotic Recombination, Garrett Buzzard

All Dissertations

The genome is constantly at risk to damage from environmental and normal cellular processes. Double-strand breaks (DSBs) are one of the most deleterious forms of DNA damage as unrepaired DSBs ultimately result in cell death. Homologous recombination (HR) is a conserved DNA repair pathway that utilizes a homologous chromosome as a template for DNA synthesis to repair the DSBs relatively error-free. HR is active in both mitotic and meiotic cells but meiotic HR is initiated by the introduction of programmed DSBs into the genome. The process of HR repairs the DSBs and results in a physical connection between homologous chromosomes …

Mirna Regulation Of Skeletal Muscle Hypertrophy, Maslyn Greene

All Dissertations

Muscle tissue is vital to animal survival and economically essential to livestock producers. Reduced muscle growth can occur from various reasons, including genetics, nutrition, and the pre and postnatal environment. Understanding the mechanisms behind muscle growth can aid in developing strategies to increase muscle mass. Several methods to increase muscle mass in livestock animals are currently being pursued, including nutrition, hormonal therapy, and genetic selection. One newly developing avenue is using miRNA technologies to change the expression of protein-coding genes. miRNA are a type of RNA that regulate over half of protein-coding gene expression. Here we evaluate muscle characteristics such …

Buried Forensics: A Rhetorical/Material Analysis Of Gendered Death, Sarah Richardson

All Dissertations

My dissertation, titled Buried Forensics: A Rhetorical/Material Analysis of Gendered Death, illustrates how othered women who did not adhere to societal norms have been silenced, excluded, forgotten, and erased in public memory. I examine the rhetorical means through which historical women have been gendered in death. Death rhetorics, I argue, illuminate the relationship between past and present violence in conjunction with memory practices. Depending on the reasons specific women were othered, death rhetorics elucidates how these women became, and continue to be, marginalized. Specifically, my three body chapters examine the lives and deaths of women who participated in sex …

Electron-Transfer Mediated Photo-Switching In Nanoparticles, Liaoran Cao

All Dissertations

Previous publications from our lab demonstrated viable approaches to design a photo-switching nanoparticle with arguably superior brightness and photostability resulting in an improved resolution in localization-based microscopy, as compared to other photo-switching dyes or particles. As a follow-up, this dissertation is focused on two major tasks: first, developing nanoparticles with better photo-switching properties for super-resolution imaging; second, trying to achieve a better physical picture of the mechanisms involved in photo-switching, including polaron dynamics, charge transfer, and energy transfer. A new class of photo-switchable nanoparticles was developed by blending conjugated polymer semiconductor with fullerene-based electron acceptors, and further blending with polystyrene …

Expansion Of The Diazacyclobutene Motif For Antiparasitic Evaluation, Brock Alexander Miller

All Dissertations

Molecules containing N-heterocycles are prevalent in pharmaceutical settings. The ability to generate highly functionalized molecules containing N-heterocycles in very few synthetic operations is valuable for drug discovery. Our group has developed a two-step synthesis to access a rarely studied diazacyclobutene scaffold via a formal [2+2] cycloaddition between 4-phenyl-1,2,4-triazolinedione and electron-rich thioalkynes. Our interest in this scaffold increased exponentially from promising preliminary biological evaluations against a protozoan parasite, Trypanosoma brucei. While we were able to double the number of historical examples of this scaffold, there were significant limitations in our methodology. The most notable limitations were the lack …

Examining The Influence Of The Classroom Environment On Motivation, Belonging, And Academic Confidence In Engineering Education: A Relational Developmental Systems Approach, Robert O'Hara

All Dissertations

This dissertation explores the impact of the classroom environment on undergraduate engineering students by integrating three manuscripts using the process-person-context-time (PPCT) model within Bioecological Systems Theory. Each manuscript focused on students’ sense of belonging, motivation, and academic confidence. The study confirms prior research suggesting a link between students' perceptions of the environment and their sense of belonging, motivation, and academic confidence. The findings highlight the complex nature of student and classroom environment relationships throughout their college experience. Moreover, the results are demonstrated across different engineering majors. Overall, this dissertation highlights the significance of understanding the complex interactions between students and …

Investigation Of Fatigue Response With Analytical And Machine Learning Models And Hygroscopic Analysis Of Asymmetric Bistable Cfrp Composites, Shoab Ahmed Chowdhury

All Dissertations

Asymmetric bistable carbon fibre reinforced plastic (CFRP) composites enable a broad range of applications as they can sustain multiple stable configurations and have small snap-through load requirements. These unique features, coupled with their light strength-to-weight and stiffness-to-weight ratios, have made them preferred options for multifunctional systems. This study investigates the fatigue and hygroscopic response of 2-ply, [0/90] bistable CFRP laminates and proposes predictive modeling approaches for improved performance.

While previous studies widely researched and documented the fatigue of general composites in axial loading, fatigue analysis of asymmetric bistable composites in the out-of-plane snap-through direction is inadequate. This study performs fatigue …

Investigating The Potential Of A Cell-Based Gene Editing Therapy For Inherited Metabolic Liver Disease, Ilayda Ates

All Dissertations

Inherited metabolic diseases (IMDs) affecting the liver are relatively rare but collectively have a prevalence of 1 in 800 live births. These diseases result from autosomal recessive single-gene mutations, leading to organ dysfunction and potentially fatal consequences if left untreated. One potential therapeutic strategy for IMDs of the liver involves using CRISPR-Cas9-induced loss of function mutations. However, translating this approach into the clinic is limited by the need for safe and effective CRISPR delivery methods. Adeno-associated viral vectors (AAVs), commonly used for CRISPR delivery, are associated with significant safety and efficacy concerns, including risks for immunogenicity, off-target mutagenesis, and genotoxicity …

Extensional Flows Of Polymer Solutions In Planar Microchannels, Mahmud Kamal Raihan

All Dissertations

Non-Newtonian fluids such as polymer solutions often flow under microscale extensional conditions in many natural and engineering flow fields such as in microfluidic chips, porous rocks, biological membranes and filters, printheads in additive manufacturing, etc. The changing cross sectional areas of the internal flow passages therein exert additional extension on the flow along with the shearing. Numerous studies have been dedicated to understanding the extensional flows of polymer solutions over the years. However, most of these studies only focused on flexible polymers exhibiting elasticity in their macroscopic rheology, whereas rigid polymers that portray shear-thinning but often elude elasticity in the …

Atom Economical Reactions Of Terpenoids And Post-Consumer Plastics With Sulfur, Charini Maladeniya

All Dissertations

The production of Ordinary Portland Cement (OPC) and its uses have a complicated environmental impact, which is influenced by infrastructure development and building operations as well as CO₂ emissions, which account for 7% of all worldwide CO₂ emissions. Due to the increasing population, production is still ongoing. The search for cement and construction materials produced with zero to low CO₂ emissions is therefore continuous. Finding recyclable, CO₂ gas-free biocomposites with high sulfur content that can rival the mechanical properties of popular building supplies like Portland cement is the primary objective of the research discussed in this …

Accurate Orientation Control Of Tendon Driven Continuum Robots That Exhibit Elasticity, Manu Srivastava

All Dissertations

This dissertation makes new contributions to the modeling and implementation of Tendon Driven Continuum Robots (TDCRs). Specifically, motivated by 3D printing of concrete using a continuum hose robot in construction applications, we focus on TDCRs featuring compliance in the robot backbone and actuating tendons, e.g. surgical robots/endoscopes/catheters with tendon actuation. We expand previous mechanics-based models to show how and why such compliance significantly restricts performance when traditional kinematics-based planning and control techniques are applied.

The main contribution of this work is a new Elasticity Compensation(EC) model that explains why the ad hoc approach of preloading/pretensioning the tendons compensates for compliance …

Acceleration Methods For Nonlinear Solvers And Application To Fluid Flow Simulations, Duygu Vargun

All Dissertations

This thesis studies nonlinear iterative solvers for the simulation of Newtonian and non- Newtonian fluid models with two different approaches: Anderson acceleration (AA), an extrapolation technique that accelerates the convergence rate and improves the robustness of fixed-point iterations schemes, and continuous data assimilation (CDA) which drives the approximate solution towards coarse data measurements or observables by adding a penalty term.

We analyze the properties of nonlinear solvers to apply the AA technique. We consider the Picard iteration for the Bingham equation which models the motion of viscoplastic materials, and the classical iterated penalty Picard and Arrow-Hurwicz iterations for the incompressible …

The Influence Of Allostery Governing The Changes In Protein Dynamics Upon Substitution, Joseph Hess

All Dissertations

The focus of this research is to investigate the effects of allostery on the function/activity of an enzyme, human immunodeficiency virus type 1 (HIV-1) protease, using well-defined statistical analyses of the dynamic changes of the protein and variants with unique single point substitutions ¹. The experimental data¹ evaluated here only characterized HIV-1 protease with one of its potential target substrates. Probing the dynamic interactions of the residues of an enzyme and its variants can offer insight of the developmental importance for allosteric signaling and their connection to a protein’s function. The realignment of the secondary structure elements can …

Injectable Immunomodulatory Strategies To Enhance Muscle Recovery Following Injury, Tai Huu Huynh

Graduate Theses and Dissertations

Although skeletal muscle displays an astonishing regenerative capacity, injuries or diseases that resulted in bedridden or chronic muscle wasting can overwhelm this intrinsic feature of skeletal muscle and lead to functional deficit (range of motion and/or strength) and overall reduction in quality of life. Microenvironmental cues within injured skeletal muscle dictate regenerative and repair process which are tightly coordinated interplay among resident cells, cells recruitment and immune response following an assault in the muscle extracellular matrix (ECM). The successful regeneration of functional tissues requires both appropriate modulation of the inflammatory response, and activation of a variety of cell populations. Biomaterials …

What Covid-19 Tweets Reveal About Risk Perception And Safety Preventative Measures And Behaviors Two Years Into A Pandemic, Elizabeth Vargas

Dissertations

The purpose of this study was to examine individuals Covid-19 risk perceptions two years into a long running pandemic. Data was collected analyzing risk perception and safety preventative measures to understand how individuals communicated risk in a health crisis that lasts more than two years. 116,401 tweets were collected from March 7-18, 2022, and analyzed utilizing a qualitative content analysis design. Four main classes were identified from the data which looked at how individuals perceived risk, how individuals determined risk from information that was shared, what preventative measures individuals were utilizing, and how individuals were living after the SARS-CoV-2 pandemic …