Digital Commons Network^™

On Quasi-Stationary Distributions Of Stochastic Sis Epidemic Models, Boyoung Hur

All Theses

We study a stochastic SIS (Susceptible-Infected-Susceptible) epidemic model, in which individu-als in a population are divided into two classes: “Susceptible” to the infection of a disease, and “Infected” by the disease. We assume the population size N is fixed. The state process, which measures the num-ber of infected individuals, is modeled as a continuous time Markov chain (CTMC). The CTMC has an absorbing state 0, and it will eventually die out by reaching the absorbing state. However, it appears to be persistent over a long time period before extinction. Such behavior can be understood by the study of quasi-stationary distributions. …

Florida Spotted Skunk Ecology In A Dry Prairie Ecosystem, Stephen Nicholas Harris

All Theses

The eastern spotted skunk (Spilogale putorius) is a species of conservation concern in many portions of its range and has experienced a decline since the early to mid-1990s. However, little is known about the subspecies that inhabits peninsular Florida, the Florida spotted skunk (S. p. ambarvalis), which may still be abundant. To gather more information on this diminutive carnivore's ecology and to clarify its role as a predator of the endangered Florida grasshopper sparrow (Ammodramus savannarum floridanus), we conducted studies in 2016 and 2017 on the den site selection and diet of Florida spotted …

School Leaders' Levels Of Political Engagement With The Policy Environments Surrounding Their Professional Roles, Seth D. Young

All Dissertations

Policymakers at the federal, state, and local levels rely upon school and district leaders to implement educational policies with fidelity. However, such policies are not often implemented as intended due to a variety of potential factors, including school leaders' lack of engagement in policy development. This study addresses the critical, yet understudied, role of school leaders and their levels of political engagement in a state located in the southeastern United States. Specifically, this quantitative study of 358 public school leaders in this specific state examined the extent to which school leaders are, in fact, engaged with the policy environments that …

Variable Selection For Complex Data With Sparsity: An Application In Gwas, Tianhui Wei

All Dissertations

In this dissertation, we investigate the limitations of several methods that have been proposed for variable selection in recent decades, and in particular we explore how these limitations arise in genome-wide association studies (GWAS). Three often discussed categories of methods include ordinary least squares, penalized regression, and Bayesian approaches, but while there have been efforts in the past to apply these techniques to GWAS, it remained unclear whether or not one approach was superior to the others, or if certain scenarios might favor a given method. In this research, our results from two real data sets reveal that the three …

Multidentate Ligand Design For The F-Elements, Ashleigh Kirstin Smith Sockwell

All Dissertations

The wide use of the f-elements, including nuclear weapons, nuclear energy and radiopharmaceuticals, has led to the growing unwanted accumulation of the lanthanides and actinides in the environment. The removal of these metals requires the design of highly selective ligands that take advantage of their complex chemistry (wide degree of covalency and high coordination numbers). Additionally, the environments these metals are typically being removed from involve a complicated mixture of other metals and strong counterions. Ligand design for the f-elements requires high selectivity and the formation of stable complexes in a wide range of environments. Ethylene diamine tetraacetic acid (EDTA) …

Development Of Biomimetic Models Of Human Cardiac Tissue, Dylan Jack Richards

All Dissertations

The leading cause of death worldwide is cardiovascular disease (CVD). Myocardial infarction (MI) (i.e., heart attack) makes up ~8.5% of CVD and is a common cause of heart failure with a 40% five-year mortality after the first MI. This highlights a substantial patient population and an urgent need to develop new therapeutic strategies (e.g., regenerative cell therapies). Moreover, this also indicates that current models may not sufficiently recapitulate human cardiac tissue. To date, drug development strategies have largely depended on high throughput 2D cell models and pre-clinical testing in animal models of MI leading to minimal improvements in the heart …

Exploring Underrepresented Doctoral Students' Conceptualizations Of The Student-Advisor Relationship In Chemistry, Aubrie Lynn Pfirman

All Dissertations

While it is typical for doctoral students in the sciences to have a faculty advisor, not all students can name a mentor for their doctoral journey. Noted as the most important factor in determining a student's success and satisfaction in graduate school, the student-advisor relationship is an important area for expanded study and analysis to fill in the gaps in understanding of our doctoral education system. This study details the various ways in which underrepresented chemistry doctoral students view and perceive their relationships with their faculty advisor. I used purposeful sampling to select 16 underrepresented doctoral chemistry students at public, …

Complexation Of Copper And Iron By Biologically Relevant Sulfur- And Selenium-Containing Small Molecules, Jaime Melissa Murphy

All Dissertations

Misregulation of cellular copper and iron can increase labile pools of these metal ions, increasing oxidative damage and leading to neurodegeneration in Wilson's, Parkinson's, and Alzheimer's diseases. Chapter 1 of this dissertation provides an overview of the thermodynamic stability constants of Cu(II), Cu(I), Fe(II), and Fe(III) with weakly binding amino acid ligands, including sulfur- and selenium-containing amino acids and drugs such as methimazole and penicillamine. Understanding these metal-amino-acid interactions provides insight into the role of cellular amino acids as ligands for labile metals. Stability constants of Cu(II) and Fe(II) with the sulfur- and selenium-containing amino acids methionine, selenomethionine, methylcysteine, methylselenocysteine, …

Synthesis, Biofunctionalization, And Application Of Magnetic Nanomaterials, Benjamin David Fellows

All Dissertations

Since their inception in the late 1970's magnetic nanomaterials have sparked heavy research into their use in the biomedical field. Their unique magnetic properties allow the magnetic particles to be the base for a large array of expiremental medical techniques, from treatments of disease, diagnostic tests, imaging aids, and more. In this manuscript, each stage starting from novel particle synthesis, functionalization with bioactive molecules, and innovative application is explored, specifically using the techniques magnetically mediated energy delivery, magnetophoresis, magnetic resonance imaging. The reproducible synthesis of nanomaterials is necessary if any further engineering application is going to be done. Using a …

Assessment Of Aboveground Net Primary Productivity And Carbon Pools, Detrital Biomass, Community Structure, And Species Composition Across A Floodplain Forest Of The Congaree River, Gavin D. Blosser

All Dissertations

Floodplain forests offer services to society in the form of species diversity, wood production, sequestration of carbon, and buffering capacity critical to water quality. These services are dependent upon maintenance of hydrological connections and sedimentation dynamics of these systems that determine site specific heterogeneous microsite distributions yielding specific community structure, species composition, and productivity rates. The study area was within South Carolina’s Congaree National Park (CONG), and consisted of a micro-topographic gradient across the Congaree River floodplain differing in sedimentation rates and inundation periodicity and intensity. The research was designed to take advantage of this gradient to help bridge information …

Cyanobacterial Toxins: Managing Human-Health And Ecological Risks From Microcystins In Surface And Drinking Waters, Ciera Marie Baird

All Dissertations

Cyanobacteria blooms that produce endotoxins (e.g. microcystins [MCs]) are increasing spatially and temporally in critical freshwater resources worldwide. Due to the potential for human-health and ecological risks from exposures to MCs, designated uses for freshwater resources are often inhibited by MC-producing cyanobacteria blooms. As evidence builds for the risks from MC exposures, as well as financial losses resulting from colonization of MC-producing cyanobacteria in freshwater resources, effective and efficient risk management strategies are urgently needed. The overall goal of this dissertation was to contribute information that supports progress in risk intervention for MC-producing cyanobacteria as well as MCs. To support …

Materials Science Of Blood Clot Formation In Insects: Experimental Methods For A Multiscale In-Situ Investigation, Patel Aprelev

All Dissertations

This dissertation is structured around the development of a micro and nano-rheological instrument capable of measuring mPa·s-level viscosity of nanoliter droplets and micron thick films in a 10-20 second timeframe and using it to study the kinetics of formation of a blood clot in insects. To understand the materials science behind this clot formation, we enrich the microrheological study with studies of extensional rheology of various maturity stages of clots as well as studies of the surface tension isotherms, dynamic surface tensions, and surface rheology. To study the rapidly changing structure of the clots, we employ high magnification microscopy and …

Some Interesting Effects Of High-Frequency Non-Resonant Harmonic Excitations On The Slow Response Of Duffing Oscillators, Abdraouf Abusoua

All Dissertations

This dissertation investigates the response of Duffing oscillators to bi-harmonic ex-citations consisting of a soft resonant component and a hard high-frequency non-resonant component. To this end, the dissertation uses approximate analytical solutions, numerical simulations, and an especially-designed experimental module to detail the influence of non-resonant excitation on the resonant response for oscillators with symmetric/asymmetric, mono and bi-stable potential energy functions. For mono-stable Duffing oscillators, we demonstrate that the high-frequency excitation has a substantial influence on the shape of the potential energy function associated with the slow dynamics. In specific, we show that the hard excitation stiffens the slow response for …

Diversification And Speciation Patterns Of Ground Beetles (Coleoptera, Carabidae) And Rove Beetles (Coleoptera, Staphylinidae, Pselaphinae) In The Highlands Of Ecuador, Sofia Isabel Muñoz Tobar

All Dissertations

The tropical Andes are a biodiversity hotspot for numerous evolutionary lineages. Allopatric speciation and paleoclimatical events are the major drivers for species diversification in the tropics, especially for páramo species which show high diversity and endemicity. This dissertation elucidates speciation and diversification patterns of widely distributed species of beetles from isolated páramo patches across Ecuador, to provide insight into basic evolutionary processes for Andean insect species. Sampling targeted 17 sites in the páramo ecosystem (3500 – 4000 m), with pitfall trapping, hand collecting and leaf litter sampling. One nuclear and one mitochondrial marker were used to assess the genetic diversity …

Evaluation Of A Human Papillomavirus Genotyping Assay For Cervical Cancer Screening In Tanzania, Kandali S. Kapie

School of Biological Sciences: Dissertations, Theses, and Student Research

Abstract: Mucosal high-risk Human papillomavirus (HR-HPV) has been identified as the primary factor in causing cervical cancer, the most common cancer in women of low and middle-income countries (LMICs). Cervical cancer screening, incorporating the HPV test shown to be more advantageous than screening by visual inspection with acetic acid (VIA) alone. However, due to resources constrain these countries could not afford the available HPV tests. We, therefore, validated a cost-effective Multiplex PCR HPV (mPCR) assay, a recently developed assay for detecting sixteen genital HPV, fourteen HR-HPV and 2 low-risk genotypes. We postulate that this HPV multiplex assay will be at …

Deception From Parents To Romantic Partners, Xiaoti Fan

Graduate Theses and Dissertations

Deception plays an important role in every type of relationship, particularly for the two most intimate relationships: parent-child and romantic. People usually learn behaviors and communication strategies from their parents and enforce or adjust them in other types of relationships based on various personal as well as social influences. The purpose of this study is to examine the strategies and motives young adults use with their parents and romantic partners when they convey deceptive messages, and explore how people apply patterns of deception from their parent-child relationships to their romantic relationships. In this study, two aspects of deceptive behavior are …

Antibacterial Activity Of Polygonum Pulchrum Blume Ethanol Extract On Staphylococcus Aureus And Escherichia Coli, Asman Sadino, Idin Sahidin, Wahyuni Wahyuni

Pharmacology and Clinical Pharmacy Research

The emergence of resistant bacteria strain has become a global health concern. It encourages the exploration of potential antibacterial agents, particularly from natural sources. The aim of this study was to investigate the antibacterial activity of ethanol extract of root, stems, leaves, and flowers of Polygonum pulchrum Blume against Staphylococcus aureus and Escherichia coli, through disc diffusion method using cup-plate method. Inhibition zone against S. aureus from roots, stems, leaves, and flowers ethanol extract were 3.5 mm, 2.5 mm, 2.25 mm, and 2.62 mm, respectively, while the inhibition zone against E. coli were 2.25 mm, 2.12 mm, 1.62 mm, and …

The Effectiveness Of Project-Based Learning In The Science Classroom, Jordan Tegrootenhuis

Master's Theses & Capstone Projects

The purpose of this action research project was to determine the effect of project-based learning on middle school science students. A science classroom was taught with a traditional method for a unit and data was collected to be measured for growth. Then another class was taught with project-based learning on the same unit with data collected to measure their growth. Analysis of the data collected suggests that while both strategies are effective in providing growth of knowledge, project-based learning showed a greater growth within special education, at risk, and ESL students.

Academic And Musical Success By Gender Separation, Adam Radcliffe

Master's Theses & Capstone Projects

This literature review presents the history of the traditional American coeducational classroom, studies regarding the results and benefits of implementing gender-separated classrooms, and the discussion of how music education classrooms could find value in the research relating to gender separation. With the allowance of increased studies regarding single-sex versus coeducational classrooms in the United States since the early 2000s, more researchers are aiming to understand what setting is most advantageous for students and their overall academic experience. The literature review will present information from scholarly-based articles, research study findings, and other reputable sources that highlight the statistical results and overall …

Fascicle Arrangement In College-Aged Athletes, Jacob Goodin

Electronic Theses and Dissertations

Purpose: To compare muscle architecture variables between sport and sex in competitive athletes, and to compare muscle architecture with performance variables in strong versus weak athletes, and good versus poor jumpers. Methods: The vastus lateralis (VL) and lateral gastrocnemius (LG) muscles of 139 collegiate athletes were collected using ultrasonography to determine muscle thickness (MT), pennation angle (PA), fascicle length (FL), and relative fascicle length (FL_rel). Absolute and relative peak power, absolute and relative isometric peak force, and jump height were measured in a subset of baseball and soccer athletes. A 5x2 factorial analysis of variance (ANOVA) was used …

August 2018 Commencement Program, Bowling Green State University

Commencement Programs

No abstract provided.

Embryology And Wing Development In A Dragonfly (Tramea Onusta), Valeria M. Casas

Theses and Dissertations

Most phylogenetic research within the insect phylogeny is focused on higher order taxons. Therefore, to better understand insect wing and flight origin, genetic studies on more primitive insect orders is necessary. Odonata, the order including dragonflies, is one of the earliest insect taxa to develop wings. Hox genes are highly conserved regulatory genes involved in embryonic development of organisms. Hox gene expression studies in insects allow improved insight of body plan development including wings. Embryonic development of dragonfly, Tramea onusta, was analyzed at various developmental stages. Developmental genes Antennapedia, Distal-less, Ultrabithorax, abdominal-A, Abdominal-B, engrailed, Cadual, engrailed 2, Wingless, nubbin, …

Clustering Mixed Data: An Extension Of The Gower Coefficient With Weighted L2 Distance, Augustine Oppong

Electronic Theses and Dissertations

Sorting out data into partitions is increasing becoming complex as the constituents of data is growing outward everyday. Mixed data comprises continuous, categorical, directional functional and other types of variables. Clustering mixed data is based on special dissimilarities of the variables. Some data types may influence the clustering solution. Assigning appropriate weight to the functional data may improve the performance of the clustering algorithm. In this paper we use the extension of the Gower coefficient with judciously chosen weight for the L2 to cluster mixed data.The benefits of weighting are demonstrated both in in applications to the Buoy data set …

Post-Transcriptional Regulation Of Rsma In Pseudomonas Aeruginosa, Ian Miller

Electronic Theses and Dissertations

Pseudomonas aeruginosa is a Gram-negative bacillus found in numerous environments. Gene regulatory mechanisms such as; Two-Component Systems, transcriptional and post-transcriptional regulators, and small non-coding RNAs control the expression of virulence factors that allow P. aeruginosa to initiate acute infections and persist as a chronic infection. A significant post-transcriptional regulator involved in these regulatory networks is the Regulator of Secondary Metabolites (RsmA). In this study, we investigated the contribution of a putative stem-loop on expression of RsmA. We constructed rsmA leader fusions to measure translation with and without the stem-loop present. Secondly, we introduced point mutations to disrupt the formation …

Characterization Of A Variant Of Tuberous Sclerosis Complex 2 And Its Interaction With Rheb, Sowmya Sivakumar

Graduate Theses and Dissertations

Protein-protein interactions are vital in maintaining proper function and homeostasis in cells. Some signaling pathways are regulated by G-proteins that work like switches to activate and deactivate pathways. Mutations in these proteins, their effectors or the interaction between proteins may cause dysregulation of signals that can lead to many diseases.

Rheb, Ras homology enriched in brain, is a Ras family GTPase that is vital in regulation of the mTOR (mammalian target of rapamycin) pathway that signals cell proliferation and growth. Due to the low intrinsic GTPase activity of Rheb, a GTPase activating protein (GAP), Tuberous Sclerosis Complex 2 (TSC2) down …

Determining The Effect Of Locally Delivered Bioactive Modulators On Macrophage Activation At The Implantation Site Of Different Biomaterials In Rats, Kamel Alkhatib

Graduate Theses and Dissertations

Altering the foreign body reaction by targeting macrophages has been of interest in the biomaterials field to improve the integration of longevity of implanted biomedical devices. The objective of this dissertation was to study the effect of locally delivered bioactive modulators on macrophage activation at the implantation site of different biomaterials in rats. Iloprost, a prostacyclin analog, was tested for its ability to direct macrophages to their pro-wound healing phenotype after the implantation of microdialysis probe in the subcutaneous space of male Sprague Dawley rats. This study showed that iloprost can shift macrophage activation states in vivo to the pro-wound …

Networks In Nature: Applying Cultural Ecology For Stewardship, Shelby Lasaine

College of Liberal Arts & Social Sciences Theses and Dissertations

The purpose of this research is to describe the historical context and systemic structure of the Western agrarian estate model to locate opportunities for strategic solutions to environmental degradation in a way that balances cultivated and conserved natural resources. In part 1, landholders are identified as a point of leverage in the agrarian system. Part 2 goes over the historical development of the Western estate and state traditions, which support landholders by having instituted land administration and information systems to enfranchise their activity. The systemic theory that underlies the Western model is outlined in part 3, describing how social and …

Associations Of Functional Connectivity And Walking Performance In Multiple Sclerosis, Rachel E. Bollaert, Kyle Poe, Elizabeth A. Hubbard, Robert W. Motl, Lara A. Pilutti, Curtis L. Johnson, Bradley P. Sutton

Exercise Science Faculty Research and Publications

Background

Persons with multiple sclerosis (MS) often demonstrate impaired walking performance, and neuroimaging methods such as resting state functional connectivity. (RSFC) may support a link between central nervous system damage and disruptions in walking.

Objectives

This study examined associations between RSFC in cortical networks and walking performance in persons with MS.

Methods

29 persons with MS underwent 3-T brain magnetic resonance imaging (MRI) and we computed RSFC among 68 Gy matter regions of interest in the brain. Participants completed the Timed 25-foot Walk as a measure of walking performance. We examined associations using partial Pearson product-moment correlation analyses (r …

An Interface Of The Taste And Reward Systems In The Brainstem And Its Role In Feeding, Louis Saites

Theses and Dissertations (ETD)

We eat what tastes good. We also eat because it is necessary for our health. In fact, some of the most nutritious foods (e.g., vegetables) are often less appetizing, and the tastiest (e.g., fast food, ice cream) may be the least healthy. Despite the former, we may also have a lower limit of what we accept at which point nutrition becomes irrelevant (e.g., “spinach is just too yucky”). Further, we may eat unhealthily because of overwhelming urges. We investigated the complex interactions of taste and feeding at the neurobiological level using the experiments described.

In one sense, this neurobiology begins …

Understanding The Impact Of Bcrp And Pgp Efflux Transporters On The Disposition Of Their Endogenous, Xenobiotic And Dietary Substrates, Samit Ganguly

Theses and Dissertations (ETD)

Breast Cancer Resistant Protein (BCRP) and P-glycoprotein (PGP) are membrane-bound efflux transporters that transport multiple chemical classes of compounds and act as barriers to tissue permeability, thereby regulating tissue exposure of their substrates. The role of these transporters in therapeutic resistance of their xenobiotic substrates due to their expression and efflux function at target organs/tissues, especially in brain and intestine, is well established, which has fueled investigation toward identification of their inhibitors. Multiple clinically used drugs and dietary chemicals have been reported to inhibit these transporters and potentially increase the exposure of concomitantly administered BCRP and/or PGP substrates, which might …