RSS 1.0Dissertations
ABOUT THE COLLECTION
The UA Dissertations Collection provides open access to dissertations produced at the University of Arizona, including dissertations submitted online from 2005-present, and dissertations from 1924-2006 that were digitized from paper and microfilm holdings.
We have digitized the entire backfile of master's theses and doctoral dissertations that have been submitted to the University of Arizona Libraries - since 1895! If you can't find the item you want in the repository and would like to check its digitization status, please contact us.
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Recent Submissions
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Epidemic Change Detection via Shifted Maximum SubarraysThe epidemic change-point problem arises in applications where a sequence exhibits a temporary deviation in its mean over an unknown interval. Classical approaches are based on the scan statistic, which requires maximizing a normalized sample mean over all possible segments. As a result, exact computation of the scan statistic involves $O(n^2)$ operations for a sequence of length $n$, which greatly limits its applicability to large datasets.In this work, we introduce a new computational framework based on the shifted maximum subarray (SMS) problem. We establish that the scan statistic can be derived from the SMS solution path, thereby transforming a quadratic-time optimization into an empirically near-linear-time procedure. This result provides an exact and scalable algorithm for computing scan statistics without approximation. We further develop permutation-based and hybrid inference methods that enable efficient and reliable significance calibration. The proposed approach achieves accurate type I error control and competitive power, as demonstrated through simulations and real data analyses.
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When Love is Action: A Critical Love Ethic Praxis Framework for Educator Practice in Secondary SchoolsThis qualitative study examined how educators and school-based staff understand and enact a love ethic as a framework for supporting Black and Latino boys in secondary education. Grounded in bell hooks' conceptualization of a love ethic and CRT's structural critique of inequitable schooling, this study responds to the persistent misinterpretation of student behavior among Black and Latino boys and the overreliance on punitive, compliance-driven disciplinary practices in schooling contexts shaped by layered stressors and traumas, including homelessness, immigration fear, family instability, and mental health crises. Data were collected through semi-structured interviews and reflective journaling with five secondary educators and school-based staff, using a narrative inquiry design guided by the six tenets of a love ethic: care, commitment, trust, responsibility, respect, and knowledge. Four findings emerged: Relational Presence and Emotional Attunement as the foundation of all engagement; A Love Ethic as Disruptive and Counter-Systemic Practice, in which educators actively challenged compliance-driven norms and deficit-based interpretations of Black and Latino boys; Emotional Labor and Boundaries in Loving Work, naming the structural cost of this work and the necessity of boundary-setting as a condition of sustainability; and Centering Identity and Humanity Through a Love Ethic, which positioned affirmation not as supplemental care but as a corrective to disproportionate misinterpretation and exclusion. This study introduces Critical Love Ethic Praxis, a framework that intertwines hooks' love ethic with CRT's structural analysis, contributing to existing scholarship on love, care, and equity in education by demonstrating that relational presence, enacted daily through the six tenets, is not supplemental to equitable schooling but its foundation.
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Essays on Artificial Intelligence and Human Behavior in the MarketplaceGenerative artificial intelligence (GenAI) is rapidly reshaping the marketplace, yet critical questions remain about how people perceive, communicate with, and collaborate alongside these systems. This dissertation investigates the relationship between AI and human behavior in the marketplace through three dimensions: people, process, and performance. The first essay examines consumer perceptions of AI-using service providers. Across five experiments, we find that consumers evaluate services less favorably when providers use AI, even when informed that AI improves service quality, because they perceive AI-using providers as less warm and less competent. The second essay investigates how communication style shifts when marketers instruct GenAI rather than human colleagues. Across nine studies, we find that marketers naturally prioritize their instrumental goals by using a lower density of filler words, including pleasantries, hedges, and expressions of gratitude, when instructing GenAI, because communicating with GenAI deactivates interpersonal goals such as rapport building and impression management. Contrary to popular advice, prioritizing instrumental goals during GenAI communication improves the quality of GenAI’s marketing output. The third essay explores how organizational review structures shape human–AI collaboration. Across seven experiments, we find that workers who anticipate outcome-focused review modify AI-generated content less, effectively outsourcing rather than collaborating with AI. This effect attenuates when reviewers can observe the process alongside the outcome. Together, these three essays offer insights for researchers, practitioners, and policymakers by illuminating the user perceptions that shape AI adoption, the communication processes that govern human–AI interaction, and the organizational structures that determine human–AI collaboration quality.
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Understanding the Impact of STEM College and Career Preparation ProgramsThis qualitative case study examined how participation in the Imagine Your STEM Future (IYSF) program shaped high school students’ and undergraduate mentors’ self-efficacy, STEM identity, and career development following engagement in the AquaSTEM curriculum. Grounded in Social Cognitive Career Theory (SCCT; Lent et al., 1994), the study explored how mentoring and contextual factors influenced participants’ academic and career-related beliefs. Data were collected through on-on-one interviews with undergraduate mentors, focus groups with high school students, and observations during program implementation. Analysis followed a constant comparative approach, progressing from theory-informed sections to themes grounded in participants’ lived experiences. Findings coalesced into four interconnected themes: mentoring as a catalyst for identity development, development of outcome expectations and future orientation, contextual supports and persistence pathways, and structural barriers shaping access and opportunity. Mentoring facilitated identity exploration for high school students and reinforced identity consolidation for undergraduate mentors. As participants developed STEM identities, they articulated evolving educational and career expectations. Persistence was supported through relational networks, program structures, and culturally grounded supports, while structural barriers, including financial constraints and limited access to institutional knowledge, shaped perceptions of opportunity and feasibility. Implications highlight the importance of culturally responsive mentorship and structured programming in supporting self-efficacy, STEM identity, and career development to help shape their persistence in STEM. Future research should examine longitudinal outcomes and further explore how structural conditions intersect with individual and relational processes in shaping STEM pathways.
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Optimization of Transcranial Acoustoelectric Brain Imaging of Neuronal Currents in a Human Head ModelMapping brain function in humans requires high spatial and temporal resolution when resolving fast, localized neural activity. While scalp electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have advanced neurological research, EEG has poor spatial resolution and fMRI lacks temporal sensitivity. These inherent limitations create a critical gap in non-invasive electrical brain mapping at the neuronal scale, limiting progress in diagnosing and treating disorders such as epilepsy, Alzheimer’s disease, Parkinson’s disease, and depression.Transcranial Acoustoelectric Brain Imaging (tABI) with neuronavigation is an emerging method for mapping neuronal currents through the human skull. In tABI, ultrasound (US) is focused and steered within the brain while surface electrodes record the resulting acoustoelectric (AE) interaction signal, enabling the direct mapping of current density. A key advantage of tABI is its ability to achieve millimeter-scale spatial resolution with millisecond-scale temporal resolution, determined primarily by the US focal size and acquisition rate, addressing a major limitation of conventional electrophysiological and hemodynamic imaging techniques. However, several challenges remain. Evoked neuronal current densities in the human brain are weak (typically 0.01–0.5 mA/cm² under normal conditions) with a spatial resolution of 5 mm, requiring high sensitivity for reliable detection, and overlapping activity—such as ictal and background signals—demands high selectivity to accurately distinguish and localize sources at the voxel level. These constraints highlight the need for advanced signal processing strategies to improve both detection sensitivity and source separability in tABI. The three main objectives of my dissertation are to: 1) Improve tABI sensitivity and selectivity under seizure activity using data-driven methods, including Singular Value Decomposition (SVD) and Wiener filtering (WF), 2) Validate tABI in a human head model with a real skull for detecting and mapping weak, neuronal-like currents, and 3) Develop real-time, continuous tABI scanning as a translational step toward human application. Across all studies, the proposed framework significantly improved the sensitivity and selectivity of tABI in a human head model. Spatial Wiener filtering increased SNR depending on waveform type, with optimal performance at a ~5.2 mm kernel size, while preserving spatial resolution. Singular Value Decomposition (SVD) showed that the first 2–4 components captured >90% of the signal variance, enabling effective separation of overlapping dipole sources under both 200 Hz and broadband EEG stimulation. Detection limit analysis demonstrated reliable identification of weak currents down to ~0.1 mA, with reported sensitivity reaching ~71 µA for long-duration seizure-like waveforms. Corresponding current density sensitivity was on the order of ~400 µA/cm²·MPa. Real-time tABI achieved acquisition rates of up to ~400 cross-sections per second, enabling continuous imaging of a 9 s seizure waveform and multi-channel mapping across EEG configurations. Overall, these results demonstrate millimeter-scale (~1–4 mm) spatial resolution and millisecond-scale temporal resolution, confirming the capability of tABI to localize weak, dynamic neuronal-like currents in realistic transcranial conditions.
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Work System Factors in CRNA Burnout: A Macroergonomic PerspectiveBurnout is an occupational phenomenon with far-reaching consequences for both healthcare professionals and healthcare systems. Although widely recognized among nurses and physicians, burnout remains understudied among CRNAs, despite their high-risk, high-demand work environment. The purpose of this study was to describe the macroergonomic contributors, preventive factors, and consequences of burnout among CRNAs within the anesthesia work system. A qualitative descriptive design was used, with semi-structured interviews guided by the SEIPS 2.0 model to explore CRNAs’ experiences with burnout in relation to the anesthesia work system. Participants came from various practice settings and geographic areas across the United States. Thirty-eight participants completed the online survey fully and were invited to take part in a semi-structured interview, with fifteen completing it in August and September of 2025. Analysis revealed three primary findings: autonomy and respect, the ability to practice at full scope, and change, emerging as central conditions shaping burnout experiences. When autonomy, respect, and full-scope practice were supported, participants reported decreased burnout and improved satisfaction. Conversely, when these conditions were constrained, participants reported higher levels of burnout. However, unique to this population, burnout was not experienced as a static endpoint. Instead, in almost all cases, it served as a signal prompting CRNAs to reassess their lives and initiate change, including modifying their workload, transitioning practice settings, seeking different supervision models, or focusing on well-being initiatives. These findings suggest that supporting CRNAs' well-being requires attention to how the work system is structured, not just how individuals cope, and provide a foundation for future research and organizational efforts to improve sustainability in CRNA practice.
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Unraveling Analgesic Cell Signaling and Circuit Mechanisms of Compounds Derived from Natural ProductsChronic pain is a debilitating condition that affects one in five people in the United States adult population. Limited efficacy and/or harsh side effects limit many pain drugs, driving the need for alternate analgesics. In our past research, we have shown that terpenes, small hydrocarbons found in Cannabis sativa, are capable of reducing nociception in mouse models via multiple receptor targets. Furthermore, we showed the terpenes geraniol, linalool, β-pinene, α-humulene, and β caryophyllene are efficacious in the treatment of mouse chemotherapy-induced peripheral neuropathy (CIPN). By utilizing CRISPR knockdown and the small molecule inhibitor istradefylline, we showed that terpenes act in CIPN through the activation of the Adenosine A2a Receptor (A2aR) in the spinal cord. However, the cell type and spinal circuitry for A2aR-induced antinociception by terpenes are unknown. For our model, we used male and female CD-1 mice treated with paclitaxel (2 mg/kg) over 7 days to induce CIPN. Here we show that the terpenes geraniol and β-caryophyllene produce comparable antinociception to morphine in cold allodynia in the acetone drop assay, mechanical pain, in the percent withdrawal assay, and were significantly antihypertensive in heat-induced pain, in the hot plate assay, when compared to vehicle at at least one time point. However, these terpenes were not antinociceptive in cold, mechanical, or heat pain assays in uninjured mice. Using immunofluorescence, we found that the A2aR was strongly upregulated in the spinal cord by CIPN to determine if this upregulation is the result of a pain-relieving feedback mechanism we induced CIPN then treated mice with istradefylline (3.2 mg/kg). Istradefylline significantly increased the nociception in the CIPN paw withdrawal assay, suggesting that this increase results as a feedback mechanism downregulating pain transmission. Given the known role of the A2aR as a stimulatory GPCR, we hypothesized that the A2aR is localized in inhibitory interneurons in the spinal dorsal horn and act by inhibiting neuronal pain transmission. Using immunofluorescence, We further observed that this A2aR expression was found in 95% of neurons, as measured by colocalization with the neuronal marker NeuN. Following this, we found that the A2aR is expressed in 74% of inhibitory interneurons, as measured by colocalization with the marker Pax2. We then used Pax2+ cell-selective CRISPR knockdown of the A2aR by using the Pax2 promoter to drive Cas9 expression along with a gRNA targeted to the A2aR. This resulted in a complete loss of terpene antinociception in CIPN, strongly suggesting that terpenes work through the A2aR in this specific cell population to relieve pain. To further confirm these findings, we used Fos staining in spinal cord, showing that Fos activation was increased by CIPN and repressed by terpene treatment. We showed similar results with pERK where treated with CIPN along had a significant increase compared to vehicle and geraniol-treated CIPN spinal cord had signal similar to vehicle-treated mice. Future experiments will include measurement of evoked GABA release in response to terpenes as an activity analysis of ascending nociceptive neurons. Taken together, we show that terpenes have antinociceptive effects in neuropathic pain via the A2aR on Pax2+ inhibitory interneurons in mouse spinal cord. With this work, we aim to identify the detailed mechanism by which terpenes relieve neuropathic pain, and establish a scientific basis for their use as a novel non-opioid pain therapeutic. Finally, we sought to link Src kinase signaling in microglia to Heat shock protein 90 (Hsp90) induced increased antinociception. Previously, our lab discovered that inhibiting Hsp90 in the spinal cord through intrathecal administration of 17-N-allylamino-17-demethoxygeldanamycin (17-AAG), in mice, led to an increase in morphine anti-nociception, which could enable an opioid dose-reduction strategy. Here, we hypothesized that Src kinase was upregulated by 17-AAG treatment to cause this increase. To test this hypothesis, CD-1 mice were treated with 17-AAG and the Src inhibitor Src-I1 or Src CRISPR knockdown, followed by morphine. The enhanced anti-nociception seen with 17-AAG was completely abolished in the Src inhibitor groups in tail flick and paw incision pain models, suggesting that Hsp90 inhibition activates Src signaling to lead to enhanced opioid pain relief. Analysis by Western blotting showed upregulation of Src by 17-AAG treatment with the opioid agonist DAMGO, and also suggested that Src is upstream of ERK in this signaling cascade. Immunofluorescence confirmed the upregulation of Src in the spinal dorsal horn and co-localized activated Src to microglia. Inhibition of microglia with minocycline/PLX3397 mimicked the 17-AAG effects, while activation with lipopolysaccharide reversed them, suggesting that microglia could regulate these pain states. Finally, we used microglial-specific CRISPR knockdown to confirm that microglial Src is essential to the enhanced opioid anti-nociception observed with spinal Hsp90 inhibition. These observations elucidate a key molecular mechanism by which Hsp90 regulates microglia and opioid signaling, creating potential targets to improve opioid treatment.
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Indigenous Film as a Storytelling PracticeIn “Indigenous Film as a Storytelling Practice,” Indigenous cinema is examined as a continuation of Indigenous storytelling practices grounded in relationality, oral transmission, and community accountability. Rather than approaching cinema as an aesthetic object or representational archive, the central question concerns how narrative authority persists and is reconfigured when stories rooted in collective epistemologies enter audiovisual form and circulate across divergent audiences. Through close analysis of Inuit, Kiowa, Yolngu, Aymara, and Kurdish case studies, attention is given to the interdependence of adaptation, collaborative production, and distribution infrastructures in sustaining narrative legitimacy. Formal strategies—durational pacing, repetition, non-linear temporality, untranslated dialogue, and spatial orientation—operate as regulatory mechanisms that position viewers within specific relations to land, language, and memory, while community-centered authorship complicates director-centric models dominant in film theory. As these works move through festivals, educational circuits, community screenings, and digital platforms, the social work of storytelling shifts, foregrounding questions of jurisdiction over meaning and the dispersal of accountability. Comparative proximity does not assume equivalence among distinct political histories; it identifies structural affinities in how films rebuild conditions of address under pressure from displacement, linguistic suppression, and constrained sovereignty. Indigenous cinema thus emerges as a site where oral tradition, collective authorship, and circulation converge, extending narrative reach while insisting that interpretation remains inseparable from relations.
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Life History Implications of Symbiont Acquisition for the Leaffooted Bug Leptoglossus ZonatusMost insects are associated with symbiotic microbes acquired from their environment. These microbes are ingested from the host’s environment, are localized in the gut, and supplement the host’s diet with critical nutrients. While many insects can receive benefits from diverse microbial communities, reliance upon a single environmentally acquired symbiont is likely to present risks to the host, should the symbiont be absent or rare in the environment. The arboreal leaffooted bug, Leptoglossus zonatus (Hemiptera: Coreidae), forms a symbiosis with bacteria of the genus Caballeronia, which must be acquired by 2nd instar nymphs from their environment. Bugs that fail to acquire their symbiont rarely survive to adulthood, and those that do have reduced body size and do not reproduce. Due to the cost of failing to acquire their symbiotic partner, I asked 1) whether L. zonatus is able to readily acquire Caballeronia in the tree canopy, 2) If Caballeronia is rare, whether delaying symbiont acquisition influences host fitness, and 3) whether Caballeronia can be transmitted horizontally as an alternative to environmental acquisition. To investigate the first question, nymphs were caged on individual tree branches and allowed to forage and develop. Aposymbiotic (symbiont-free) nymphs were caged with potential environmental reservoirs (soil, water, phyllosphere) or horizontal sources (e.g. conspecific bugs) of the symbiont. I found that in this setting, acquisition of Caballeronia was uncommon, suggesting a cost to dependence on an environmentally-acquired partner. In addition to the risk that nymphs may not acquire the symbiont in the environment, should Caballeronia be rare or at low abundances, symbiont acquisition may be delayed, and delays may present consequences for host fitness. I then investigated the impact of delaying symbiont acquisition by providing nymphs with Caballeronia at different time points following development to the 2nd instar. To assess fitness costs, I recorded acquisition rates, survivorship, development time, adult weight, and development of the M4 symbiotic organ with fluorescence microscopy. I found that acquisition delay negatively influenced all measurements of performance, and the consequences of delay compounded as it was prolonged. The results suggest a finite window for Caballeronia acquisition, ~1 week following development to the 2nd instar, and these results highlight an additional potential cost for this type of symbiosis. To answer the third question, I investigated if L. zonatus released Caballeronia in its feces, and if feces could serve as a source of the symbiont. I assessed L. zonatus feces to determine the presence and abundance of Caballeronia, and assessed which life stages excreted bacteria. I found that Caballeronia was present in feces, and almost exclusively released by adult bugs. I then addressed whether nymphs provided with feces from Caballeronia-colonized adults were able to acquire the symbiont from feces, and whether Caballeronia acquired from feces is equivalent to cultured Caballeronia for bug performance. Bugs fed Caballeronia from fresh feces, like those fed cultured symbiont, were almost universally able to acquire the symbiont. However, feces-fed bugs showed significantly longer development times, reduced survivorship, and reduced adult mass. Together, this work indicates potential costs for insects that rely on free-living bacteria for critical nutrition, and informs future research into the ecological dynamics and evolutionary stability of environmentally transmitted, obligate symbioses.
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Improving Pre-Anesthesia Staff Knowledge and Counseling Practices on Smoking CessationBackground: Smoking is a modifiable risk factor that increases the risk of many postoperativecomplications, including delayed wound healing, adverse respiratory events, and prolonged recovery. Evidence shows that preoperative smoking cessation interventions, even brief counseling, can improve surgical outcomes. Purpose: The purpose of this DNP project was to improve the knowledge, attitudes, and practices of pre-anesthesia clinic staff at MountainView Regional Medical Center related to smoking cessation counseling for surgical patients. The aim was to integrate evidence-based smoking cessation education into preoperative counseling workflows to support patient engagement and reduce postoperative complications. Methods: The design of this quality improvement project was a pre- and post-survey educational session to assess the impact of the intervention using a Smoking Knowledge, Attitudes, and Practices (S-KAP) questionnaire. Results: 12 pre-anesthesia clinic nurses participated in the intervention. Knowledge scores improved significantly following the education session (median 22 [IQR 21-23] pre-intervention vs 24.5 [IQR 24-25] post-intervention; Wilcoxon p =.006). Attitudes demonstrated some increase but did not reach statistical significance, with a Wilcoxon p= .36. Practice domain scores increased substantially from a median of 4.5 (IQR 1.5-9.5) pre-intervention to 20 (IQR 15.5-20) post-intervention (p < .001), indicating significant improvement in smoking cessation assessment, counseling, documentation, and referral behaviors. Conclusions: A brief, targeted educational intervention improved pre-anesthesia clinic staff knowledge and significantly increased smoking cessation counseling practices. Integrating structured smoking cessation education into preoperative workflows may be a practical strategy to enhance perioperative risk reduction efforts.
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Promoting Healthy Gestational Weight Gain with Individualized Prenatal Nutrition EducationBackground: Arizona has one of the highest maternal mortality rates among all 50 states, ranking at 11. In Arizona, the prevalence of excessive gestational weight gain has nearly doubled over the last 10 years. Excessive gestational weight gain is associated with an increased risk of maternal morbidity, reaching up to 39%. Purpose: The purpose of this quality improvement project was to implement and evaluate patient education individualized based on responses in a nutrition assessment effect on patient satisfaction, self-efficacy, and engagement of obstetric patients. Methods: The setting for this project took place in a high-volume outpatient obstetrics-gynecology clinic. Eight individuals volunteered to participate in this single 20-minute session at the end of their routine prenatal appointment. Consent was acquired by the project director prior to the administration of the pre-intervention survey and nutrition assessment. The project director provided nutrition education tailored to each participant. A post-intervention survey was administered, and no further follow-up was required. Results: Participants had a mean pre-pregnancy BMI of 30.26 and an average gestational age of 26 weeks. Measures of elf-efficacy, satisfaction, and engagement mean score slightly increased post-intervention. A significant key finding is that only 1/8 (12%) participants knew the appropriate amount of gestational weight gain. Conclusions: Unhealthy gestational weight gain is a modifiable risk factor that poses a threat to population health. Patients do not have the proper knowledge of healthy GWG, and they are motivated to learn more. The intervention in this project is an effective, sustainable intervention that focuses on improving self-efficacy, engagement, and satisfaction. These three outcomes are important in improving health outcomes.
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Design and Synthesis of Molecular Wires for Gold Mechanically Controlled Break Junctions (MCBJs)This dissertation presents a systematic investigation of structure–property relationships governing charge transport in single-molecule junctions and extends these principles to the design of advanced π-conjugated materials. The central objective is to understand how molecular electronic structure, linker chemistry, and molecule–electrode interface geometry can be rationally controlled to tune conductance and optoelectronic properties. Chapter 2 focuses on verdazyl radicals as stable open-shell systems for molecular electronics. A series of thiomethyl-functionalized verdazyl derivatives was designed and synthesized to evaluate how substituent effects and functionalization patterns influence single-molecule conductance in gold mechanically controlled break junctions (MCBJs). This work establishes structure–transport relationships in radical systems and highlights their potential for enhanced conductance and spin-dependent transport. Chapter 3 investigates oligophenylene vinylene (OPV3) derivatives as conjugated molecular wires. Two key challenges are addressed: overcoming the anticorrelation between renormalization energy and ionization energy through balanced substituent design and exploring alternative linker groups beyond sulfur-based systems. Furthermore, OPV3 derivatives incorporating dihydrobenzo–thiophene (BT), isocyanide, and amine linkers were synthesized and studied to evaluate how backbone modification and linker identity affect charge transport in single-molecule junctions. Chapter 4 examines the role of linker group denticity and spatial arrangement in molecular conductance using a series of N-heterohexacene derivatives. By systematically varying the number and placement of thioether linkers while maintaining a constant conjugated backbone, this work demonstrates that molecular geometry, particularly the orientation of linker groups relative to the π-system plays a dominant role in determining conductance, challenging the assumption that increased denticity necessarily enhances transport. Chapter 5 extends these design principles to highly conjugated macrocyclic systems through the synthesis of a zinc phthalocyanine (ZnPc) derivative incorporating pyrene-fused pyrazaacene (PPA) building blocks. The resulting expanded π-conjugated macrocycle, combined with solubilizing substituents, addresses limitations associated with aggregation and poor processability in conventional phthalocyanines, while enabling tunable optical and electronic properties. Overall, this work demonstrates that charge transport in molecular systems is governed by an interplay of intrinsic electronic structure, linker chemistry, and interfacial geometry. By integrating synthetic design with single-molecule measurements and materials development, this dissertation provides key insights and design principles for the development of next-generation molecular electronic and optoelectronic devices.
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Use of Ultraviolet-Visible Spectroscopy to Provide Ion-specific Nutrient Control of N, P, K, Ca in Hydroponics SolutionHydroponics is the heart of most systems for controlled environment agriculture (CEA) providing several simple implementations to offer direct control over the moisture and nutrients provided to the crops. The more accurately growers can control the solution being provided, the longer they can reuse the same solution and the more consistent the crop quality. The goal would be direct control over all fourteen to eighteen nutrients that plants need to grow, but the primary nutrients – nitrogen, phosphorous, and potassium (N, P, K) – are often considered to be the most critical. While ultraviolet-visible (UV-Vis) spectroscopy has been proposed for this purpose for years, and been demonstrated to be usable to get within ten percent of the true value for N and K, this paper lays out a succinct and practical approach to calibration and measurement that can be used to implement a near real-time control system that can be used to control N, P, K and calcium (Ca). The intent being to speed adoption of such a technology by making it cheap and easy to implement. Special attention is paid to laying out what information can in theory be reused and what a grower would need to maintain calibration on site. This is presented as a six-step process for deployment based on lessons learned from these experiments. A notional implementation of the control system and a discussion of practical use in lunar greenhouse growing is also provided. Overall the final algorithm only uses four wavelengths of light, a small number of compounds that are already components of Hoagland and similar solutions, and is computationally light enough to be able to run comfortably on a minute-by-minute basis.
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Three Essays on Emotion, Coordination, and Economic BehaviorEconomic experiments provide controlled environments to examine the causality between economic variables, test theoretical frameworks, and offer insights for the development of new economic theory. In this dissertation, I employ laboratory experiments to study how behavioral factors influence individual decision-making and strategic interactions. This dissertation consists of three chapters. In the first chapter, "Minimum-effort game under stochastic monitoring", I design and experimentally test a coordination device "stochastic monitoring" in classical minimum-effort games, where group production is determined by the minimum effort provided. In these games, strategic uncertainty regarding others' contributions often results in inefficient, low-effort outcomes. Under stochastic monitoring, an automated supervisor monitors individual effort with a probability p and imposes a non-deterrent marginal fine c for deviations from the maximum effort level. I test the effectiveness of three treatments, Full-p, High-p, and Low-p, in improving coordination compared to a baseline when stochastic monitoring is absent. All treatments have the same expected marginal fine pc, but the values of p and c vary. Subjects were randomized into groups of four and interacted repeatedly. Stochastic monitoring was introduced after groups experienced coordination failure. The results show that stochastic monitoring significantly improves coordination across all treatments. Notably, the Low-p treatment (low probability of monitoring, high marginal fine) is the most effective, outperforming the Full-p treatment. Further analysis reveals that these improvements are not driven by direct feedback from punishment or individual traits. This research demonstrates that stochastic monitoring is an effective coordination device in environments where the production function has a "weakest-link" feature. It also shows that low-cost monitoring protocols (represented by low probability of monitoring) can achieve outcomes equal to, or better than, high-cost alternatives. In the second chapter, "Emotional echoes: Reference-dependent preferences and emotion dynamics" (joint with Clément Staner), we use a laboratory experiment to explore individual investment decisions when the decision-maker is frustrated. Traditional economic models often struggle to explain why unrelated past frustrating events influence subsequent decisions, even if wealth and beliefs remain unchanged. This chapter addresses the gap by investigating the dynamic role of emotions, specifically "frustration", in decision-making under uncertainty. We propose a theoretical framework where falling below a subjective reference point triggers frustration. Frustration accumulates over time and affects utility negatively through an emotional cost function. The model distinguishes between two environments: return-control (R), where investment increases the size of the reward, and probability-control (P), where investment increases the likelihood of success. In a within-subject experiment, subjects made investment decisions both before and after they experienced a frustrating event. Frustration was triggered via losing a lottery unrelated to the investments. We hypothesize that whether subjects increase or decrease investment depends on their sensitivity to frustration (curvature of the emotional cost function). Furthermore, ceteris paribus, subjects have a stronger incentive to invest in the P environments to increase the probability of removing the emotional cost. The results provide evidence for heterogeneous behavioral responses: Subjects with diminishing sensitivity to frustration escalate investment following a frustrating event, while those with increasing sensitivity de-escalate. These individual-level investment changes offset each other in aggregate data, which can potentially explain the lack of consensus in the existing "sunk cost" literature. While we confirm the directional predictions regarding investment changes across environments, the differences in magnitude of these changes between R and P are not statistically significant. The last chapter, "Emotions and market activity: Cause or consequence?" (joint with Daniel Gotsman and Charles N. Noussair), disentangles a long-standing debate about the causality between emotions and stock market movements. Despite widespread anecdote associating "exuberance" with high prices, or "fear" with low prices, the direction of causality remains poorly understood. We use a laboratory experiment to exogenously induce emotions of Happy, Fearful, or Neutral among traders. Subjects watched video through virtual reality (VR) headsets to induce the targeted emotional states; traders in the same market watched the same video. They then traded assets with stochastic dividends in a continuous double-auction market. This method allows us to directly compare the price and trading volume across markets under different emotional states, while holding other variables constant. The results show that exogenously inducing emotions does not affect asset pricing or trading volume, both on the session level and on the individual level. However, we find a robust reverse relationship: Market outcomes significantly affect subsequent self-reported emotional states. Specifically, traders who earned more experience significant increase in Joviality and decrease in Fear. These results suggest that the market euphoria observed in the field when price increases is a consequence of traders accruing greater earnings, rather than a cause of increased price.
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Assessing Midwives’ Compliance with ACOG Hypertension Guidelines in Underserved AreasBackground: Hypertensive disorders of pregnancy (HDP) are leading causes of maternal morbidity and mortality in the United States (US) and contribute significantly to preventable complications. In rural and underserved communities, limited access to specialty care, delayed recognition, and inconsistent application of clinical guidelines increase the risk of adverse outcomes. Certified nurse-midwives (CNMs) play a vital role in early identification and management; however, variability in knowledge and interpretation of diagnostic criteria may impact timely intervention.Purpose: This Doctor of Nursing Practice (DNP) project evaluated and enhanced midwives’ knowledge and clinical recognition of HDP based on the American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin No. 222 through an asynchronous educational intervention. The project aimed to improve knowledge, confidence, and application of hypertension management principles among CNMs in a rural Arizona clinic. Methods: This quality improvement (QI) project used a quantitative pre- and post-intervention design guided by Lewin’s Change Theory and Knowles’ Adult Learning Theory. Six CNMs were recruited and completed a pre-survey assessing knowledge, confidence, and guideline adherence. Participants then completed an asynchronous educational module on evidence-based hypertension management, followed by a post-survey. Data were analyzed using descriptive statistics and paired t-tests. Results: All participants completed the study (100%). Baseline knowledge was strong in hypertensive thresholds and emergency management, with gaps in diagnostic classification and pharmacologic sequencing. Post-intervention improvements were noted in protein-to-creatinine ratio criteria and delivery recommendations for severe preeclampsia. Persistent variability remained in classification and seizure prophylaxis management. Self-reported confidence improved across all participants. Conclusions: Although baseline knowledge was substantial, gaps in guideline application persisted. Asynchronous education improved confidence but showed mixed knowledge gains. Ongoing structured education, case-based learning, and decision-support tools are recommended to improve retention, consistency, and maternal outcomes in rural settings.
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Exploring Essential Components of Addiction Recovery through the PRISM Model of WellnessThis study explored essential components of addiction recovery through the PRISM Model of Wellness, an integrated and multidimensional framework grounded in existential psychotherapy and positive psychology. The PRISM model conceptualizes recovery across five domains: Perspective, Relationships, Intention, Strength, and Meaning. Using deductive thematic analysis, this exploratory study examined participant experiences of relapse and recovery through the lens of the PRISM model. Findings indicated that participant narratives reflected themes consistent with the five PRISM domains, including 10 emergent subthemes with the major domains as critical to sustaining long-term sobriety. The subthemes were narrative identity, cognitive reframing, positively impacting others, receiving positive impacts from others, resilience, personal responsibility, existential meaning, and spirituality. Some of the domains and subthemes overlapped, suggesting recovery is a robust and multidimensional process. Findings from the study extend the existential and positive psychology literature by illustrating how recovery narratives can be understood through an integrated, multidimensional lens of wellness. Implications include integrating PRISM-informed interventions into clinical practice and counselor training. Future research should examine the development and validation of PRISM-based assessment tools and interventions applied to individuals with substance use and mental health disorders.
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Neural and Autonomic Correlates of Approach-Avoidance Conflict Following Interoceptive ManipulationDecisions are often shaped not only by information surrounding us, but also by our mental-emotional state at the time of the decision. A racing heart, discomfort, or changes in nutrient needs can all influence whether an individual engages in a challenging situation or chooses to withdraw. We examined how bodily signals affect decision making and how they are represented in the brain. Using rhesus macaques performing tasks in which ongoing reward had to be weighed against the cost of enduring a mildly aversive stimulus, peripheral physiological state was pharmacologically altered to test whether changes in the body were sufficient to bias behavior. Perturbations that shift the body into a state mimicking high arousal biased behavior toward avoidance, showing that bodily state can causally influence cost–benefit decisions. To investigate the neural basis of this effect, we recorded single-neuron activity was recorded from anterior cingulate cortex and amygdala while monkeys performed the task. Activity in both areas exhibited ramp-like dynamics related to the timing of stopping, consistent with an evolving decision process. Despite this, we did not identify a clear neurophysiological correlate of the altered bodily state. When we examined the relationship between heart rate and neural firing to determine how bodily and neural signals covary, we found reliable correlations, but their temporal relationship suggests that the brain is leading the body, which may explain why we did not identify a neural correlation of peripheral manipulation. Together, these findings show that while bodily state can shape decisions, the task-relevant activity of cingulate–amygdala circuits is likely not biased by it.
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Leveling Up Motivation in Undergraduate Research: A Mixed Methods Study on a Digital Game-Based WorkshopUndergraduate research experiences have been shown to enhance academic performance, retention, and sense of belonging, particularly for historically marginalized students. However, limited research has examined research-training interventions outside of traditional STEM laboratory contexts or explored how digital learning environments may support the development of research-related motivational beliefs. This study investigates the potential of a digital game-based learning (DGBL) workshop to improve research self-efficacy and expectancy–value–cost (EVC) beliefs among undergraduate students. Guided by Situated Expectancy-Value Theory (SEVT), this mixed-methods study evaluated the effectiveness of StatQuest, a four-day DGBL research workshop implemented in Southern Arizona Institution. Participants (n = 39) completed pre- and post-surveys measuring research identity, research self-efficacy, and EVC beliefs. Paired samples t-tests indicated a statistically significant decrease in cost of research following participation in the workshop, t(38) = −.59, p = .04, d = −.34, and a marginally significant increase in research self-efficacy, t(38) = 1.80, p = .07, d = .29. Moderation analyses further revealed that prior research experience influenced how motivational beliefs related to research identity following the intervention. Specifically, the interaction between T2 value and prior research experience on T2 research identity was significant, β = −.50, p = .040, where value beliefs were more positively predictive of research identity for research inexperienced students compared to those with prior experience. The interaction between T2 cost and prior research experience on T2 research identity was also significant, β = .66, p = .006, where research inexperienced students’ cost beliefs negatively predicted T2 research identity, whereas the slope was weaker for students with prior experience. Semi-structured interviews with participants provided additional context, providing complementary findings to the moderation effects of prior research experience on research identity, supporting reasons why students without prior research experience had steeper slopes compared to their counterparts. Findings suggest that DGBL interventions may serve as accessible entry points into research training, particularly for students without prior research experience. Implications highlight the potential of DGBL environments to support motivational development and expand access to research opportunities for historically marginalized undergraduate students.
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Increasing Awareness of Secondary Traumatic Stress in Nursing through Education InterventionBackground: Nurses are at high risk of experiencing secondary traumatic stress (STS) due to frequent exposure to their patient’s life-threatening scenarios. The negative emotional and mental effects can worsen burnout and decrease quality and safety of patient care. Purpose: The purpose of this Doctor of Nursing Practice (DNP) project was to implement and evaluate a direct educational intervention on secondary traumatic stress among nurses and nursing students to increase awareness of symptoms and resources to mitigate the impact on professional quality of life. Methods: A pre–post design was used to evaluate a standardized education session for working nurses and nursing students. Participants completed a survey on secondary traumatic stress causes, symptoms, and resources before and after attending an education session. Results: Mean Likert scores on a 5-point scale increased from an overall pretest mean of 3.10 to 4.44 post-intervention reflecting substantial improvement in both theoretical understanding and practical coping strategies for STS. Conclusions: A brief STS-focused education session produced more than a one-point mean increase in self-reported STS awareness, representing a meaningful educational effect on both student nurses and practicing nurses. These findings support incorporating concise, targeted STS education into nursing curricula and staff development as a feasible strategy to strengthen resilience in nursing.
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Three Essays on Access, Supply, and Policy in Opioid MarketsThe United States opioid epidemic has claimed nearly one million lives over two decades, yet the forces sustaining it---from illicit supply to treatment barriers---remain incompletely understood. This dissertation examines the opioid market along a connected chain: how much of the opioid supply was diverted to non-medical use, and what happens when enforcement restricts that supply? Does effective medication-assisted treatment reach those who need it? And when a prescription exists, why do patients still fail to fill it? Each chapter addresses one link in this chain, together tracing the epidemic from its supply-side origins through the treatment infrastructure that might contain it. In the first chapter, I study the supply side of the opioid market. Using pharmacy-level opioid shipments across ten U.S. states and a structural model of medical and non-medical demand, I decompose what fraction of dispensed opioids was diverted for non-medical use. I find that 8% of pharmacies dispense opioids for non-medical use with high probability, and that over half of all opioid shipments between 2008 and 2010 were diverted. Critically, aggressive DEA enforcement actions against rogue pharmacies do not eliminate non-medical demand---they displace it. A substantial share of non-medical users migrate to the black market when pharmacy access is curtailed, potentially accelerating the transition to more dangerous substances such as heroin and fentanyl. In the second chapter, I turn to the treatment side of the crisis and ask whether expanding the supply of buprenorphine prescribers saves lives. I exploit the 2016 Comprehensive Addiction and Recovery Act, which for the first time authorized nurse practitioners to prescribe buprenorphine for opioid use disorder, interacting this federal reform with pre-existing variation in state scope-of-practice laws. Granting nurse practitioners independent prescribing authority increased active buprenorphine prescribers by 47%, raised dispensation by 26\%, and reduced opioid-related mortality by 22%. Gains were concentrated in previously underserved counties where no treatment had existed; in counties with established access, dispensation rose but mortality did not improve, with suggestive evidence of diversion into secondary markets. In the third chapter, I investigate why patients who receive a buprenorphine prescription so often fail to fill it. Using administrative insurance data from Washington State, I document that fewer than half of first-time patients successfully initiate treatment---far below fill rates for other chronic medications. I develop and estimate a sequential search model in which patients face both physical travel costs and uncertainty about which pharmacies carry buprenorphine. Search costs account for 70% of treatment failures. Providing prescribers with real-time pharmacy inventory data could raise initiation rates by 17%.
