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Exploring the Application of Repeated Microgravity Surveys to Monitor Groundwater Level Variations in Nebraska
No full textGroundwater is an important resource in the state of Nebraska for supporting industries and ecosystems. Monitoring this vast resource ensures its continued availability for generations to come. However, monitoring utilizes well data, and if a well is not present in a desired location, geophysical methods can be explored. This project tests the capability of repeated gravity surveys over Nebraska’s aquifers to monitor groundwater levels throughout 2024.
Two study areas were selected in Eastern Nebraska. The first is in Oakland, Nebraska, over a confined aquifer system. The second is in Plymouth, Nebraska, and exhibits unconfined conditions. Four sites were chosen to collect data in the Oakland study area, and only one in Plymouth, each with an observation well for comparison with the gravity data. Data collection began in April 2024 with measurements once a month during the recovery seasons (April-May, October-December), and twice a month during the irrigation period (June-September).
The results from the Plymouth survey show a strong correlation between the change in gravity and the groundwater level variations in the well (R = 0.75), which is consistent with the unconfined conditions of the aquifer. In addition, specific yield in a range of 25% to 29% was estimated for the aquifer, which aligns with published estimates for the area (20-25%). In Oakland, all four surveys exhibit similar trends in gravity. However, two sites show no correlation (R = -0.05) with gravity readings, which is expected for confined aquifer settings. The other two show a moderate correlation (R = 0.56) which suggest either a nearby recharge area or a leaky confined aquifer for these sites. This project also summarizes recommended guidelines for future gravity surveys, which are beneficial to further develop this methodology over unconfined aquifers in Nebraska. Overall, gravity surveying proved efficient for monitoring local aquifers in unconfined settings.
Advisor: Irina Filin
A UAS-centered Investigation of Vorticity Characteristics and Cold Pool Structure Across Forward and Left-flank Boundaries in Supercells
No full textSupercell internal boundaries are the locus of tornadogenesis; thus, understanding the characteristics of these boundaries, particularly in terms of vorticity, is important for identifying the role they play in tornado formation. Insight into the overall characteristics of internal boundaries and their possible role in tornadogenesis have been driven by studies reliant on numerical modeling-based experiments. Observational studies often neglect above-surface conditions or, when these observations are made, lack the spatial resolution to resolve boundary characteristics. During TORUS (Targeted Observation by Radars and UAS of Supercells) 2019 and TORUS-LItE (TORUS Left-flank Intensive Experiment) 2023, uncrewed aircraft systems (UAS) and mobile mesonets collected in-situ kinematic and thermodynamic observations across left and forward flank boundaries. Three TORUS and TORUS-LItE cases are analyzed herein with the goal of updating understanding of supercell internal boundaries. This analysis reveals that the strongest near-surface vertical vorticity is typically collocated with enhanced streamwise vorticity, baroclinic generation, and gradients in vertical motion and equivalent potential temperature. Horizontal gradients in vertical motion distributed over scales of several hundreds of meters are present in all three cases and made appreciable contributions to horizontal vorticity. Analysis of the 26 May 2023 case reveals a likely streamwise vorticity current (SVC) embedded in the head of a density current-like feature. Comparable structures are observed in the left flank boundaries of the 11 June 2019 case, but with differences in cold pool shape and pressure perturbations. In fact, lack of a meaningful pressure jump in the 26 May 2023 and 12 June 2023 cases are the primary reason the boundaries in these cases cannot be classified as a true gust front.
Advisor: Adam L. Housto
Online Prediction of Streaming Data
No full textWe present two new approaches for point prediction with streaming data based on a) the Count-Min sketch and b) Gaussian Process Priors with random bias. The methods are intended for the most general case where no true model can be usefully formulated for the data stream. In statistical contexts, this is often called the M open problem class. For the Count Min Sketch method we show that the predicted distribution function ^F converges to F under the assumption that the data consists of i.i.d samples from a fixed distribution function F. To implement the Gaussian Process Prior methods, we used representative subsets based on streaming K− means to keep the dimension of the variance matrices bounded.
We form four versions of our hash function based predictor (HBP) and compare them to six other predictors that are based on existing methods. Four are fully Bayesian and the other two are derived from the Shtarkov solution. For comparisons we use real data. In our experiments, we use absolute cumulative error as criterion for predictive success. Preliminary experiments suggest that the one-pass median version of our method performs the best compared to any other methods for data whose complexity is not based on spread. For spread-complex data, often Gaussian Processes are best. In some cases when our method is best, some of the Shtarkov methods are comparable. We argue that when this happens, our method is preferred over Shtarkov methods because of its simplicity.
Advisor: Bertrand Clark
“You Can Rise Back Up Again”: Using Photovoice to Understand Healing from Intimate Partner Violence Among LGBTQ+ Racial-ethnic Minority College Students
No full textIntimate partner violence (IPV) is a longstanding public health crisis that has been linked to deleterious mental and physical health issues and negative academic outcomes among college students. Further, IPV disproportionately affects LGBTQ+ individuals and certain racial-ethnic minority students. Campus services are not adequately meeting the needs of these survivors and these efforts would be better informed by centering students disproportionately affected by IPV. Guided by intersectionality and minority stress theories, the current photovoice study examined the strengths that fostered healing and the challenges that LGBTQ+ racial-ethnic minority survivors faced in their recovery journeys. Participants were eight LGBTQ+ racial-ethnic minority college student survivors of IPV enrolled at a four-year college/university in the United States. Participants met for six weekly group sessions to share and discuss photos relevant to their IPV experiences. Results revealed that LGBTQ+ racial-ethnic minority survivors of IPV have several strengths that supported their healing and recovery journeys, including connection to self and community, acknowledging their resilience, and feeling empowered to heal and voice their concerns about the issue of IPV. Survivors also reported several challenges they faced in their recovery, including experiences of oppression, shame, and disconnection, as well as a lack of LGBTQ+ racial-ethnic minority representation and culturally affirming and trauma-informed resources. Survivors also described the journey of healing as one that is not linear, straightforward, and often changing. Despite extreme adversity, survivors in this study possessed tremendous power and agency, enhanced by their connections. Findings from the study have implications for advancing understanding of how to support LGBTQ+ racial-ethnic minority college student survivors as it relates to future research, policy, practice, and advocacy.
Advisors: Dena Abbott and Katie Edward
Written & Directed By: The Limits of the Auteur and the Post-auteur Moment
No full textIn its common contemporary use, auteurism professes simplicity (a filmmaker’s authorship is as singular as a novelist’s), nobility (to use this framework is to respect the process and integrity of artistic genius), and flexibility (anyone with a singular voice can become an auteur). Each strand is much more complicated in ways that correspond to artistic traditions, economic shifts, and audience identification. This dissertation contextualizes the reconstruction of auteurism in the 1990s in United States cinema within the market demands of neoliberalism and the inherent aesthetic baggage that still lingers from the artistic traditions of “genius” and “authenticity” as white-male coded. Through re-evaluating the limits of the auteur, I will show why auteurism, in its late-capitalist incarnation of self-commodification, has failed to transcend white-male coding, perpetuating a limited canon of selves worth exploring and celebrating as “authentic” expressions in commercial media. This limitation in its traditional framework sets the stage for a new theory of post-auteurism that seeks to escape from the white-male genius coding that has often held back diverse voices from an equal field of expression and perceived legitimacy by communities of critics, awards bodies, and the general consensus around canonization. Auteurism from its start sought to celebrate the personal, the irreplaceable and the unique—which should lend itself to a rejection of cultural homogeneity, not an embrace of it, as has often been the case. This is the re-centering that is possible in what I call the post-auteur moment, wherein a move from the identity-politics based hierarchies of the past and its related ur-sins that led to the 1990s reconstruction can be repositioned within a broader symbolic market of identity politics as they manifest in the emergent hegemony of content in the twenty-first century. This project will begin the necessary conversation of what constitutes post-auteurism and where we see it already manifesting in the existing cinematic and transmedia landscape.
Advisor: Marco Abe
Educating the New Generation of Food Scientists through Innovative Learning Experiences
No full textFood science provides an opportunity to engage high school students in Science, Technology, Engineering, and Mathematics (STEM) by connecting classroom concepts to real-world applications. Despite the field’s relevance to public health, food safety, sustainability, and innovation, food science remains largely absent from high school curricula, and few students recognize it as a viable STEM pathway. This research addressed this gap by evaluating immersive summer camp experiences and teacher-focused curriculum review as strategies to increase food science awareness and interest among students and educators. A literature review traced the historical development and current landscape of K–12 food science education, identifying barriers such as limited student awareness, insufficient instructional resources, low teacher confidence, and minimal professional development opportunities. To address these challenges practically, a mixed-methods approach evaluated out-of-school-time summer camp programs. The three-day camp “How the Cookie Crumbles” resulted in an increase in students’ content knowledge, enhanced student interest in food science topics and careers, and deepened their understanding of the farm-to-fork continuum. Similarly, one-day summer camps, “Pizza, The Rise of the Dough,” “The Science of Ice Cream,” and “The Science of Cookies” demonstrated improvements in students’ content knowledge. Through a Draw a Food Scientist Test students’ conceptions of food scientists evolved from generic laboratory imagery to diverse roles in product development, food safety, and food processing. In addition, a transcendental phenomenological study explored high school science teachers’ experiences and perspectives as they reviewed a Next Generation Science Standards (NGSS)-aligned curriculum focused on food waste. Teachers valued the curriculum’s real-world relevance and interdisciplinary design but identified challenges related to implementation, such as pacing and district-level constraints. Suggestions for food science integration included labeling within existing curricula, reframing current instructional content, and developing elective courses. Drawing upon these insights, the “Relate, Reveal, Reach” guiding framework was established to connect food science students’ personal experience (Relate), facilitate inquiry through engaging phenomena (Reveal), and foster awareness towards food science careers (Reach). Collectively, these studies demonstrate how experiential interventions and collaborative curriculum review can enhance student learning and interest, providing practical guidance for developing sustainable, standards-aligned high school STEM programs.
Advisor: Andréia Bianchin
A Modular Paradigm for the Directly Efficient Representation of Kinetic Laser-driven Plasmas
No full textA natural inefficiency in conventional treatment of the plasma distribution arises from indiscriminate consideration of the contributions to field structure that are dynamically sourced from kinetic activity in disparate sectors of phase space. We introduce a range of techniques for model design to maximize representation efficiency without breaking key physical invariants indicative of physical reliability. An overview of varied adaptation to stable time-advance methods is given. Low-dimensional representation of a laser-driven plasma requires some creativity in differential structural modification, while direct efficiency is uncovered through the compression and rarefaction of a nonuniform momentum grid. These numerical models introduce embedded gains in computational efficiency through the implicit and explicit distribution of computational resources where they are required most. With a focus on low-dimensional settings, we outline the algorithmic structure of our numerical methods and the precise arrangement of operations appropriate to implement models variationally consistent with conservation principles in a way that is generalizable in a number of different directions. Comport towards scheme modularity and compatibility with integration-by-parts as a defining principle is demonstrated in all techniques. We apply these models to several problems requiring both accurate representation and detailed resolution of plasma phase-space.
Advisor: Bradley A. Shadwic
Thematic Analyses of Session Data with Transgender and Gender Diverse Adults Obtained During a Clinical Trial
No full textTransgender and gender diverse (TGD) adults in the United States experience high rates of discrimination and marginalization, contributing to adverse mental health outcomes. While clinical guidelines for gender affirming care have been developed, these guidelines often lack empirical grounding or specific, actionable strategies for clinicians. Although theoretical models such as the marginalization stress model and the psychological mediation framework offer useful foundations for case conceptualization, they do not fully capture the lived experiences or the resilience mechanisms of TGD individuals in therapeutic contexts. This project aims to bridge the gap between research and clinical practice through thematic analysis of therapy sessions conducted as part of a cognitive behavioral therapy (CBT) clinical intervention with 23 TGD-identified adults living in the Midwestern United States. Grounded in cognitive behavioral and broader sociocultural models of marginalization stress, this study explores how research-identified constructs, such as stigma, identity pride, and social support, manifest in clients\u27 own words and experiences. Results showed that participants described themes of internalized stigma, anticipated and experienced marginalization, gender expression distress, perceived shortcomings, isolation, and life stress as activating for distress. Core beliefs about the self and related automatic thoughts were grouped into themes of negative self-perception, social disconnection and isolation, and gender-related stress and identity challenges. Finally, participants developed rational responses as they re-appraised original thoughts, resulting in themes of self-compassion and letting go, self-worth and inherent value, and identity validation. Findings from this analysis are intended to inform and refine affirming clinical approaches, offering insight into the translation of empirical evidence into therapeutic practice for TGD individuals. These results reveal the nature of external and internal experiences which lead to further distress and the content of core beliefs and automatic thoughts, including beliefs about self-worth and value, safety as a TGD person, likability, and identity validity. Results also demonstrate the content of rational responses in relation to these beliefs and thoughts, including rejection of others’ opinions and re-affirmation of value to the self, which might be leveraged in a clinical context to promote wellbeing.
Advisor: Debra A. Hop
Rhetorics of Encounter: Toward a Biocentric Theory of Discourse
No full textEncounters with more-than-human identities are transformative moments that stand to affect dispositional and bodily change in individuals. From close brushes with wild animals in National Parks to everyday interactions with local ecologies, encounters invite us to feel and think differently about the nature of our realities. In Rhetorics of Encounter: Toward a Biocentric Theory of Discourse, I draw from interdisciplinary perspectives to disrupt the idea of rhetoric as a representational medium, arguing that rhetoric occurs not just through textual exchanges of words and symbols, but through embodied moments of contact with other responsive beings. Invoking George Kennedy’s theory of rhetoric as persuasive energy and fusing it with Gilles Deleuze’s formulation of the encounter as an epistemological disturbance, I make the case for re-thinking the encounter as a disruptive event that acts on audiences by supplying them with new imaginative possibilities. Tracing the history and etymology of the word “encounter,” I consider how the term might orient us toward different ways of conceptualizing the discourse-environment relationship. How do ideas of “invention” and “research” change, for instance, when viewed through the lens of the encounter? To what extent might the encounter support an environmentally-conscious approach to writing instruction? Rhetorics of Encounter: Toward a Biocentric Theory of Discourse invites readers to consider the rich entanglements connecting our literate lives to our ecological realities.
Advisor: Rachael W. Sha
A Quantitative Examination of the Sexual Health of Aging Black Men in Rural South Africa
No full textThis dissertation uses survey data primarily from Wave 1 of the Health and Aging in Africa: Longitudinal Study of In-depth Community in South Africa (HAALSI) which was collected in 2015 to study the sexual health of Black men in rural Mpumalanga, South Africa. Broadly speaking, I examine aging men’s sexual health as it related to HIV, well-being, loneliness, social networks and disclosure. The definition that I use for sexual health was coined by MacPhail and Campbell (2001) who define it as “not only sexual practices but also what people know and believe about sex, particularly what they think is natural, proper and desirable” (p. 3).
I focus on aging men in rural areas because the majority of existing studies on sexual health in South Africa focus on young people who are based in urban areas, ignoring rural and peri-urban locations (Qambela, 2018; Phaswana-Mafuya, Peltzer and Pengpid, 2019). Older populations are frequently ignored because there is an “incorrect assumption about their lack of sexual risk-taking” (Rosenberg et al, 2018, p. 2). This leads to earlier symptoms of AIDS-related complications being dismissed as alignments associated with aging (Munthree and Maharaj, 2013, p. 123) and seldom sexual health.
The exclusive focus on men is to move away from the general pattern of comparing men and women. Overall, in chapter four, I found that there was no association between living with HIV and feeling respected but men with higher self-reported levels of happiness and those with primary and high school education said they felt respected. I use as one of my measures of well-being. In chapter five I found that men who had tested, had a high school education and had adverse childhoods often saw themselves as being at lower risk of infection but in the absence of adverse childhoods, men who had women as sexual partners saw themselves as being at a reduced risk of infection. In chapter six I found that disclosure generally increased perceived emotional support yet people with some tertiary education reported less support. Additionally, receiving support was associated with lower odds of knowing where to go to access HIV treatment.
Advisors: Lisa Kort-Butler and Kelsy Burk