Digital Commons Network^™

Role Of Estrogen Receptor Alpha In Modulating The Circadian System In Female Mice, Victoria Alvord

Theses and Dissertations--Biology

Circadian rhythms are approximately 24-hour cycles of physiology and behavior. Circadian rhythms of eating, or meal timing, are linked to cardiometabolic dysfunction in humans. Mistimed eating, such as breakfast skipping and eating late at night, increases the risk of obesity, diabetes, and cardiovascular disease in humans. Likewise, disrupted eating rhythms cause obesity in mice. This dissertation investigates how estrogens regulate eating behavior rhythms and tissue clock timing in female mice. Chapter 1 reviews three key components critical to this work. The first is an overview of the field of chronobiology and the function of the circadian system. The second is …

Understanding The Drivers Of Marine Sediment Diagenesis In Carbonate-Bearing Sediments, Alex Reis

Theses and Dissertations--Earth and Environmental Sciences

Marine sediments serve as an important geochemical record used to study how the Earth’s climate and oceans have changed throughout geologic time. As such, it is critical to understand how these sediments can be altered following deposition on the seafloor. This dissertation targeted two key geochemical archives, carbonate and pyrite, to link changing burial conditions with the resulting marine sediment chemistry. In particular, primary carbonate minerals record several indicators of past ocean chemistry, while pyrite preserves information related to the redox state of the sediment during deposition and burial. Additionally, secondary processes associated with changes in pore fluid chemistry and …

Use Of Stable Isotope Geochemistry To Determine The Paleoenvironment Of The Pond Creek Coal Bed, Pike County, Eastern Kentucky, Vivian A. Edwards

Theses and Dissertations--Earth and Environmental Sciences

Wetlands are both critical habitats and bellwethers of the health of the environment. Coal, being the remains of wetlands, offers the possibility of understanding the evolution of wetlands over large climatic shifts. The paleoenvironment of coals can be determined from palynology, petrology, and geochemistry. Stable isotope ratios within coal, including carbon (δ¹³C), nitrogen (δ¹⁵N), and sulfur (δ³⁴S), are established tools for paleoenvironmental reconstructions. These ratios can be correlated to flora, geochemistry, macerals, and bacterial activity. However, carbon, nitrogen, and sulfur have given conflicting results in some studies and their correlation to known variables is …

On Stripping And Antipodes In Motivic Steenrod Algebras, Joshua A. Peterson

Theses and Dissertations--Mathematics

We generalize the stripping process to the (mod 2) $\mathbb{C}$- and $\mathbb{R}$-motivic settings. Throughout, we include discussion on how the process changes and the difficulties moving to more general settings. We also introduce antipodes and consider what a potential $\mathbb{R}$-motivic analogue may look like. Finally, we elaborate on how the results may be used in future work to generalize a nilpotence result of Walker and Wood.

Extensions Between Modules Defined By Lattice Paths In The Preprojective Algebra, Chloe Napier

Theses and Dissertations--Mathematics

In 2001, Fomin and Zelevinsky introduced cluster algebras which appear as coordinate rings of many varieties. We study cluster algebras coming from Richardson varieties. Leclerc gives a cluster structure on Richardson varieties using the representation theory of preprojective algebras. While this construction is very algebraic, we take a more combinatorial approach. The main goal is to find a combinatorial description for when certain cluster variables are compatible, or equivalently when modules defined by lattice paths in the preprojective algebra have trivial extensions. We extend the known results from Geiss, Leclerc, and Schröer that answer this question in the case of …

A Character Theory For Loop Representations Of Symmetric Monoidal Bicategories, Jordan Sawdy

Theses and Dissertations--Mathematics

Character theory arises in many distinct fields of mathematics, but its many instantiations often share a few key features: they arise in contexts where one object is acted on or parametrized by another, and they are often computed via "trace-like" formulas. Focusing on these properties, we present a categorical formalism for constructing such characters. We first define a notion of "loop representation" for symmetric monoidal bicategories, then build a character for such representations via the canonical symmetric monoidal trace. We then show that this character defines a symmetric monoidal functor which satisfies commutativity properties with respect to both restriction- and …

Inverse Problems For The Radiative Transport Equation In Local And Non-Convex Geometries, Faith E. Hensley

Theses and Dissertations--Mathematics

Inverse problems for the radiative transport equation (RTE) arise in a wide range of imaging applications, including optical tomography and problems motivated by non-line-of-sight imaging. Classical reconstruction methods rely heavily on ballistic, or unscattered, photons and typically require full boundary access, leading to severe instability and limited applicability in geometrically constrained settings. This dissertation investigates inverse radiative transport problems with restricted boundary data and develops reconstruction techniques based on scattered photons. The central focus of this work is the analysis and isolation of the single-collision term in the collision expansion of solutions to the RTE. By exploiting its distinct analytical …

Combinatorial Models For Nonnegativity In Flag Varieties, Williem L. Rizer

Theses and Dissertations--Mathematics

The nonnegative Grassmannian admits a widely studied cell decomposition due to Alexander Postnikov, whose cells are indexed by positroids and modeled by several equivalent combinatorial objects. Subsequent work by authors including Lauren Williams, Suho Oh, and Carolina Benedetti has further developed the combinatorics and geometry of these structures. In this dissertation, we extend some of Postnikov’s combinatorial framework to the nonnegative flag variety. While cell decompositions in this setting were previously obtained, notably in work of Konstanze Rietsch, our focus is on providing new combinatorial models that make this structure more explicit and computationally tractable. We introduce flag positroid pipe …

The Interaction Between Additive And Multiplicative Structures In Arithmetic Settings, Ali Alsetri

Theses and Dissertations--Mathematics

The first part of this thesis is concerned with Goldbach-type problems. In recent years, there has been an interest in developing density versions of Goldbach-type results. Namely, given a relatively dense subset A of the primes, one may study representations of integers as sums of primes belonging to the subset A. These density Goldbach-type results have been facilitated by the development of new tools from additive combinatorics, in particular the Fourier-analytic transference principle due to Green. We apply the transference principle to obtain a variant of Vinogradov’s theorem involving subsets of primes confined to the residue class 1 (mod 3). …

Local Energy Decay For Non-Stationary Damped Wave Operators, Nicholas Dj Arsenault

Theses and Dissertations--Mathematics

This work establishes integrated local energy decay (ILED) estimates for the damped wave equation on certain non-stationary spacetimes. The main technical result is a high frequency estimate that holds in great generality, provided that null geodesics trapped in a compact region are sufficiently damped. This is combined with low- and medium-frequency estimates to establish full local energy decay. We conclude by providing a counterexample where the damping assumption fails and local energy decay does not hold.

Understanding Möbius Inversion As Composite Of Dual Pairs, Isaac B. Kochmaan

Theses and Dissertations--Mathematics

Möbius inversion is a well-studied computational tool in number theory and combinatorics, but it exhibits a pattern which may be familiar to those who study categorical traces. In 2016, Kate Ponto and Michael Shulman characterized duality and traces in the bicategory of profunctors for a particularly nice class of one-cells. We extend these results. Consequently, we construct, for a given poset, a profunctor whose Euler characteristic is the Möbius function of said poset. In light of this, we propose a categorical notion of Möbius inversion.

Design And Advancement Of Analytical Frameworks For In Vivo Single-Photon Calcium Imaging To Characterize Temporal- And Treatment-Dependent Neural Adaptations To Opioid Exposure And Withdrawal In The Medial Prefrontal Cortex, Alexia R. Alsum Dr.

Theses and Dissertations--Pharmacy

Despite the availability of several approved medications for opioid use disorder (OUD), it remains a significant public health concern characterized by persistent neurobiological adaptations that drive relapse and impede successful recovery. The medial prefrontal cortex (mPFC), a region critical for executive control and decision-making, undergoes pronounced functional changes during chronic opioid exposure and withdrawal, yet the cellular mechanisms underlying these adaptations remain poorly understood. This dissertation aims to investigate longitudinal alterations in mPFC neural activity across opioid exposure and withdrawal using in vivo single-photon calcium imaging and newly developed computational frameworks.

Following standard preprocessing to extract and normalize calcium traces, …

Exploring The Limitations Of Substrate Scope In Dimethylallyltryptophan Synthases, Evan T. Miller

Theses and Dissertations--Pharmacy

Natural products (NPs), are the largest source of bioactive compounds in Nature, and are essential to the treatment of human disease. Nearly 50% of drugs approved for use from 1981 to 2019 owe some aspect of their development to NPs, either in terms of their structure, pharmacophore, or mechanism of action. However, NPs are difficult to structurally optimize. Chemoenzymatic methods for NP derivatization have been increasingly seen as practical alternatives to traditional synthetic methods. Prenyltransferases (PTs) are involved in the primary and secondary metabolism of plants, bacteria, and fungi, and they are key enzymes in the biosynthesis of many clinically …

Validation Of Final And Dynamic Subsidence Prediction Models Using The Influence Function Method, Carlos M. Hernandez Garcia

Theses and Dissertations--Mining Engineering

This study evaluates the Surface Deformation Prediction System (SDPS Version 7) for predicting final and dynamic subsidence in longwall mining. Using the influence function method, SDPS 7 was calibrated using data from the Quarto 7 Mine (Ohio, USA) and two panels in Anhui Province, China, to test the reliability of the method under varying geological and operational conditions, particularly low advance rates.

For the Quarto 7 Mine, monument line C provided the optimal set of subsidence parameters: SSF of 78%, tanβ of 2.97, edge‑effect offset of 160 ft, with an RMSE of 0.108 ft. These values aligned with estimates obtained …

Reciprocity-Based Transfer Function Techniques For Acoustic Source Reconstruction, Spring Isolator Characterization And Structural Damping Assessment, David Pum Thian Lal Paite Neihguk

Theses and Dissertations--Mechanical and Aerospace Engineering

Reciprocity implies that a system responds identically when the source and receiver positions are interchanged. This dissertation applies this principle to address three practical challenges in noise and vibration characterization, where conventional approaches are limited by inaccessible interfaces, constrained excitation conditions, or metrics that do not fully capture vibroacoustic behavior.

The first study develops and validates an inverse method to characterize ducted acoustic sources using acoustic free velocity. Acoustic reciprocity is applied to simplify transfer function measurements. The method is extended to large cross-section ducts, where the source is reconstructed as a collection of point sources along a plane. Validation …

Using Camera-Based Unmarked Spatial Capture-Recapture Modeling To Estimate Reintroduced Elk (Cervus Canadensis) Population Parameters And Distribution In Southeastern Kentucky, Claire Marie Muia

Theses and Dissertations--Forestry and Natural Resources

Estimation of population parameters is important for wildlife management decisions. Elk reintroduced to southeastern Kentucky experienced early irruptive population growth and are currently monitored using a statewide harvest-based statistical population reconstruction model (SPR) across the Kentucky Elk Restoration Zone (KERZ). Because the SPR model is spatially coarse and difficult to scale to the smaller management units comprising the KERZ, we conducted a spatially explicit capture-recapture study using a clustered camera-trapping array deployed for 10 weeks from June–August 2024 to estimate elk population parameters within Management Unit 4. Due to a lack of resights of GPS-marked elk, population parameters were estimated …

Understanding Knowledge And Perceptions Of The Beef Industry On A Land-Grant University Campus, Allison E. Reaves

Theses and Dissertations--Community & Leadership Development

A well-researched phenomenon in the agricultural industry is the effects of constant innovation coupled with an increasing divide between producer and consumer. This issue has been presented as especially prevalent within animal agriculture and the beef industry, a predominant concern considering Kentucky’s agricultural commodities. This study (n = 31) utilized a mixed-methods approach to understand the knowledge, perceptions, and behavior of beef consumers on a land-grant university campus. Methodologies included Python’s DeepFace emotion recognition, semi-structured interviews, and the JMALI agricultural literacy assessment. Findings revealed participants to be below expected agricultural literacy levels of high school graduates (M=11), with no …

Artificial Intelligence And African Studies, Gloria Emeagwali

Comparative Civilizations Review

African Studies is a conglomerate of multidisciplinary academic fields that include paleontology, history, literature, linguistics, philosophy, African Traditional Religion and theology, art, and Afrofuturism, as well as African Indigenous Knowledge Systems. This paper focuses on the latter, namely African Indigenous Knowledge Systems (AIKS), and African Studies, in general, from the viewpoint of two chatbots, namely, ChatGPT-4, and DeepSeek v.3. Do these models make a break with Eurocentrism and prevent unbiased information on AIKS? Are the underlying conceptual issues underpinning AIKS fully grasped, and if so, what are some relevant examples of this accomplishment? How do these programs respond to specialized …

Normative Jurisprudence & Good Government, Zachary A. Chin

Student Works

No abstract provided.

The Color Of Innovation And Law: An Analysis Of Racialized Populations Adversely Impacted By Structural Inequities In Intellectual Property Law And Biometric Technologies, R.S. Rowe

Student Works

No abstract provided.

It’S Not A Trap!: How Employers Can Adjust To Noncompete Agreement Bans & Restrictions With Fair Alternatives, Sophia D’Agostino

Student Works

No abstract provided.

An Unjustified Judicial Invention: A Case For The Removal Of The Natural Law Exception For Patentable Subject Matter, Bradley O. Schlager

Student Works

No abstract provided.

Barycentric Subdivision And Hyperbolic Geometry, Hannah Elisabeth Steger

Dissertations and Theses

Barycentric subdivision of a triangle is the geometrical process of repeatedly subdividing a triangle by connecting the midpoints of the sides to the opposite vertices. The transformations which determine this subdivision form a group acting on the hyperbolic plane, action which we will show is topologically transitive. We find specific cases when the barycentric subdivision process leads to flat triangles (all vertices on the x-axis) and, on the contrary, situations when shapes are positioned on an orbit that is a circle, hence never becoming flat. We will also analyse this process when the starting triangle is already flat and we …

Supplementary Material For Experimental Constraints On Rock And Mineral Alteration By Magmatic Gas: Implications For Mars (Safari Et Al., In Review), Natalie Zimmermann

Geosciences Research Data

This file contains supplemental data for the JGR manuscript Experimental Constraints on Rock and Mineral Alteration by Magmatic Gas: Implications for Mars (Safari et al., in review). It includes SEM images and associated EDS spectra of altered targets and phase coatings produced in gas-rock alteration experiments.

Dordt University 2026-27 Catalog, Dordt University. Registrar's Office

Academic Catalogs

Academic Catalog for 2026-27

Iere Annual Report 2026, Erin Largo-Wight, Heather Barnes Truelove, Kelly Rhoden, Jessica Barnes, Lauren Canady, Nicole Lowe, Ruby Cox, Sydney Barrett, Kathleen Hutton

Annual Reports

2026 Annual Report of the Institute for Environmental Research and Education

Counseling Professionals' Perspectives On Ai Integration In Education And Supervision: A Concept Mapping Study, Hank Crofford, Elif Bor, Gülşah Kemer

Counseling & Human Services Faculty Publications

The rapid emergence of artificial intelligence (AI) has raised important questions about how new technologies will shape professional norms and practices in counseling. The purpose of this study was to understand how counseling professionals expect AI to be integrated into counselor education and supervision (CES). Using a mixed‐methods concept mapping design, 31 participants generated and sorted statements about the potential roles, benefits, and concerns associated with AI in the profession. Participants represented diverse counseling roles, including counselor educators, licensed professional counselors, supervisors, master's‐ and doctoral‐level trainees, and other counseling‐related professionals. Standard concept mapping procedures were conducted using R, resulting in …

Impacts Of Segmenting Principle On Learner Performance And Attitude In A 3d Environment: A Mixed-Method Multiple Case Study, Kristin Herman, Mohan Yang, Jim Shifflet, Noah Glaser

STEMPS Faculty Publications

This study presents a conceptual replication of Moreno’s (Appl Cogn Psychol 21:765–781. 10.1002/acp.1348, 2007) study on the benefits of adhering to the segmentation principle when utilizing multimedia learning objects. Furthermore, this study expands upon the original by taking place in a low-immersive virtual reality environment, allowing for further understanding on the extent to which multimedia principles are still relevant. Both a synchronous and an asynchronous case are presented. Results indicate benefits for both cases in far transfer of learning. Furthermore, synchronous learners indicated a significant reduction in cognitive load and increased overall attitudes towards learning due to segmented instruction.

Optimizing Kidney Allograft Years: Underutilization Of Pediatric Donors, Nicholas Herrera, Ana Cortez, Diane Cibrik, Bradley A. Warady

Manuscripts, Articles, Book Chapters and Other Papers

Background. 

The Kidney Donor Profile Index (KDPI) score drives kidney allocation in the United States for both adult and pediatric donors, despite the calculation being primarily derived from adult donor data. A KDPI of ≤20% is considered to have the longest graft survival potential and is typically prioritized for recipients who have a low Estimated Posttransplant Survival (EPTS) score. Using KDPI to assess pediatric donor quality may underestimate graft survival and result in underutilization of these kidneys for recipients with a low EPTS score.

Methods. 

Using Scientific Registry of Transplant Recipients data, we analyzed 5-y posttransplant death-censored graft survival of …

Equity In Coastal Resilience: A Framework For University Engagement In Community-Based Projects, Juita-Elena (Wie) Yusuf, Jennifer L. Whytlaw, Marina Saitgalina, Ogechukwu N. Nwandu-Vincent, Khairul A. Anuar, Thomas Allen, Joshua Behr

School of Public Service Faculty Publications

As communities face intensifying climate hazards, it is vital to strengthen resilience in ways that explicitly prioritize social equity. This study examines how higher education institutions can better support government, nonprofit, and community partners in advancing equity-centered coastal resilience in the U.S. Utilizing a qualitative research design, we analyze discussions among researchers and practitioners during a three-day workshop. We present a framework derived from a thematic analysis of breakout group transcripts from a three-day national virtual workshop involving 113 researchers and practitioners. The analysis identified four core themes: the necessity of aligning projects with community-defined priorities; the foundational role of …