Now showing items 41-60 of 20274

    • Investigation of Heat Transfer and Entropy Production of High Temperature Molten Chloride Salts Circulation in Concentrating Solar Power Systems

      Li, Peiwen; Zhang, Ye; Hao, Qing; Alsua, Carlos; Zohar, Yitshak (The University of Arizona., 2022)
      The global warming and worsening environment on the earth has been a great concern to human society in the last two decades. The major solution to the problem is to use clean and renewable energies for electricity generation, thus reducing the use of fossil fuels and cutting emission of CO2. One of the most feasible approaches for accomplishing the goal is to significantly increase the harvest and utilization of solar energy, using Concentrating Solar Power (CSP) technology combined with Thermal Energy Storage (TES) systems.Heat transfer fluids (HTFs) are used in CSP plants to receive heat from solar concentrator and then transfer it to heat exchanger, power turbine, or thermal storage system. To achieve higher energy efficiency from the CSP systems, the development of a new generation HTF to approach a higher temperature limit by using eutectic high temperature molten chloride salts is sponsored by the U.S. Department of Energy. The first part of this dissertation is the experimental study of the convective heat transfer of the molten salt at high temperatures. For the first time, a circulation system and instrumentation of flow and heat transfer was designed and constructed to measure the heat transfer coefficient of the . Experimental measurement of the convective heat transfer coefficients of NaCl-KCl-ZnCl2 (molar fraction: 13.8%-41.9%-44.3%) inside tubes has been accomplished to find the most suitable heat transfer correlations. This provides valuable information for the design of heat transfer devices in CSP plants that use molten chloride salts as heat transfer fluid and thermal energy storage material. The second part of this dissertation mainly focuses on the analysis to the transient heat transfer phenomenon between the hot fluid and the cold pipe. Currently, most of the modern concentrated solar thermal power plants employ molten salts as the heat transfer fluid to carry the thermal energy from solar concentrators and deliver to thermal storage systems or thermal power plants for the need of power generation. For the startup operation of solar concentrators, molten salts need to be pumped to flow into the pipes which may have lower temperature than the molten salt due to cold ambient overnight or over the suspend period of operation. As the freezing point of various molten salts ranges from 220 oC to 430 oC, preventing the freezing of molten salt flowing in cold pipe is a very important requirement for the safe operation of a concentrated solar thermal power plant. A basic heat transfer analysis of transient heat exchange between molten salts and the flow pipe is conducted to find a criterion or the critical condition of preventing molten salt from freezing. The effects of molten salt flow velocity, heat capacities of molten salt and pipe, dimensions of pipes, and the initial temperatures of salts and cold pipes are all correlated theoretically in the analysis through modeling of transient heat transfer between a pipe and the fluid. The results are very helpful to the understanding and management of a safe startup of hot molten salt flowing in cold pipes on cyclic operations. The third part of this dissertation introduces details about the modeling that provides a fundamental approach for the comparison of various heat transport systems which may have different designs and using different heat transfer fluids/media (gas, liquid, or solid particles) in CSP systems. For various high temperature heat transfer fluids, such as, synthetic oils, various molten salts, and liquid metals, a general criterion is proposed in this work to evaluate the merit of fluids regarding their transport properties. For the goal of transferring a desired amount of heat, a fluid that causes less entropy production is believed to have better figure of merit (FOM). This is due to the fact that entropy production is associated with the destruction of exergy or useful energy. The entropy production in a heat transfer system in a solar thermal power plant includes the part due to the processes of heat addition and removal and the other part due to pressure losses in the flow in heat exchangers and pipes. Theoretical analysis and relevant equations for total entropy production are derived. As an example, the FOM for several heat transfer fluids used in CSP industry are compared for the goal of heat transport in the range of 50 MWth to 600 MWth. This work offers one very important approach leading to the development and optimization of a heat transport system for CSP plant with all factors considered. The investigations included in this dissertation for the heat transfer and system analysis in concentrating solar power technology are of particular interest to the renewable energy engineering community. It is expected that the proposed methods can provide useful information for engineers and researchers.
    • Are Medications Effective in Managing Tinnitus?: A Review of the Literature

      Velenovsky, David S.; Wright, Megan L.; Norrix, Linda; Dai, Huanping; Schultz, Jared; Barakat, Fadyeh (The University of Arizona., 2022)
      Objective: The purpose of this project was to evaluate the claims and efficacy of medications marketed towards tinnitus relief for adult humans. The information presented in this literature review provides insight to clinicians regarding medications that have been trialed in adults to treat tinnitus.Methods: This literature review was conducted following steps modeled after Cronin et al. (2008). Articles were identified using the following online databases: PubMed, Ovid, the University of Arizona’s online library and a review of reference lists from excluded Cochrane reviews, systematic reviews, and surveys that were identified during the search process. Results: This review identified 19 articles that fit the search criteria. These articles were categorized into the following nine drug classifications: anticonvulsive/antiepileptic, benzodiazepines, vitamins/minerals/antioxidants/herbals, anesthetics, antagonist drugs, vasodilators, antidepressants, anti-inflammatories/corticosteroids, and anticoagulants/antithrombotic. Conclusions: Future research is needed to validate the effectiveness of the medications reviewed in this project. Treatment approach for tinnitus is complex as tinnitus is multifaceted. Without the exact knowledge of etiology and mechanisms involved, treatment results for tinnitus are unpredictable. Starting or stopping any medication is not recommended without a physician’s approval.
    • Integrative Health Education For Insomnia Among The Older Adult Population

      Williams, Deborah K.; Leicher, Jonatha; Shea, Kimberly; Allen, Prettyman; Dowling, Evangeline (The University of Arizona., 2022)
      Purpose This quality improvement (QI) project aims to evaluate the healthcare providers’ knowledge and intent to use evidenced-based integrative health (IH) education plan for insomnia in older adults at the Cornerstone Long-term Acute Care Hospital in Round Rock, TX. Background The American College of Physicians Clinical Practice Guideline (CPG) for chronic insomnia for the adult population contains two recommendations, the use of cognitive-behavioral therapy and a shared-decision-making approach by the clinician and the patient discussing whether pharmacological intervention is warranted in case the CBT was ineffective. This project identifies alternative nonpharmacological approaches in a situation where both the first and second recommendations are not effective, appropriate, or the risks outweighs the benefits. Methods The Ottawa Model of Research Use (OMRU) framework inspired by Rogers Diffusion of Innovation theory guided the process of this quality improvement project, which superseded a quantitative descriptive design. This design was utilized to evaluate the healthcare providers’ knowledge of evidence-based integrative health nonpharmacological interventions for insomnia. A Google.doc pretest survey link was provided followed by a PowerPoint education presentation about the history, uses, and benefits of acupuncture, aromatherapy, and music therapy for insomnia. A posttest survey link was provided after the presentation to re-assess their knowledge and intent to use IH approaches to their practice. The pretest and posttest survey results were used as a piece of quantifiable information for analysis. Results Data collection took place in one evening. Two participants participated in this project presentation, all of which were Caucasian female, registered nurses. Both completed the pretest and posttest surveys. There were score increases seen in knowledge, comfortability, and intent to use acupuncture, aromatherapy, and music therapy as IH approaches to their practice and a clear improvement from pretest survey to posttest survey. Conclusion The pretest and posttest surveys revealed positive results of evidence-based IH approaches education presentation to the healthcare providers’ knowledge and intent to use to their practice. Future high-quality studies that focus on adapting the IH approaches into the providers’ practice would likely lead to the conceptualization of the 3rd recommendation of the existing CPG for insomnia among adults
    • Teaching Students With Emotional and Behavioral Disorders Self-Reported Practices: What Is Working and What Are the Needs?

      Liaupsin, Carl; Robertson, Kristin; Hartzell, Rebecca; Gonzalez, Taucia (The University of Arizona., 2022)
      Students with emotional and behavioral disorders (EBD) exhibit a wide variety of difficult behavior, and the responsibility of educating them is equally difficult. Students with EBD face historically bleak outcomes. Additionally, EBD teachers have had a continual nationwide shortage. They have the highest turnover rate and have more teachers on emergency certification than any other teaching group. Multiple literature analyses have concluded that evidence-based practices are widely absent in EBD classrooms, and student outcomes have had dismal improvements (Bradley et al., 2008; Gage et al., 2010; Harrison et al., 2019; Simpson et al., 2011). However, most of this research has focused on either specific intervention strategies or meta-analysis of previous literature (Bradley et al., 2008; Conroy, 2016; Conroy et al., 2008; Freeman et al., 2019; Lewis et al., 2019; Lloyd et al., 2019; Wagner et al., 2006) and have not focused on what teachers report happening in EBD classrooms. This mixed-method exploratory study examined the resources teachers reported using to support their students, the prevalence of evidence-based practices, and whether there is a correlation between access to evidence-based resources and teachers’ intent to continue teaching and confidence in their ability. This study explores some of the current instructional practices, barriers, and needs occurring in classrooms supporting EBD students in Arizona. Implications and recommendations for future research are included.
    • Online Learning Based Performance Optimization in Wireless Networks with Context Information

      Li, Ming; Zhao, Tianchi; Ditzler, Gregory; Tandon, Ravi; Zhang, Chicheng (The University of Arizona., 2022)
      Adapting to unreliable links is a key challenge to meet the high demands for next-generation wireless communication and networking. For instance, channel variations caused by multi-path fading, shadowing, and mobility, can lead to packet losses and decrease network throughput \cite{hashemi2018efficient}. This issue is especially important in a 5G/B5G system because of the adoption of millimeter-wave (mmWave) communications. MmWave signals bear much higher propagation loss than lower frequencies due to atmospheric absorption and low penetration, which is exacerbated by blocking and mobility. These challenges were mainly addressed by various physical/link/network layer mechanisms, such as transmission power, rate control, channel coding, opportunistic routing, etc. However, they all come at the expense of higher resource consumption/overhead and are limited by the intrinsic characteristics of the wireless channel. Reconfigurable antennas (RAs) emerged as a promising technology that can deal with channel variations and enhance the capacity and reliability of the wireless channel. RAs is possible to directly enhance the link performance by altering the physical channel itself. To fully exploit the advantage of RAs, optimal antenna modes/beams need to be selected in an online manner. The main challenges are two-fold: uncertainty of channel over time, and a large number of candidate antenna modes/beams. Multi-armed bandit-based online learning algorithms were proposed to address this challenge, but the main drawback of existing approaches are that their regret scales linearly with the number of antenna modes/beams, which converges slowly when the latter is large. In this dissertation, we focus on alleviating the aforementioned challenges by exploiting channel related context information. We propose several optimal online antenna mode/beam selection frameworks for SISO/MIMO single-hop wireless links and extend to joint antenna mode/beam and route selection for multi-hop wireless networks, based on the Multi-Armed Bandit (MAB) framework. First, we present two novel antenna mode pruning strategies and integrate them with Thompson sampling (TS), which exploit the relationship between antenna radiation pattern and channel state. These two algorithms pre-process the action set (reduce the number of arms in the action set) to achieve a higher convergence rate. However, it does not fully utilize channel information as context information. To fully exploit channel information, we present a Hierarchical Thompson Sampling (HTS) algorithm. The high level idea of HTS is to divide the arms into multiple clusters, first uses TS to sample a cluster and then samples an individual arm inside that cluster. Furthermore, we present two algorithms that exploit channel modeling to predict the channel conditions of unexplored antenna modes at each time step, by relating the correlation between different channel states to the underlying antenna modes. In addition, we present an efficient MAB algorithm for joint routing and beam selection in multi-hop networks: combinatorial lower confidence bound (LCB) based joint route and beam selection with channel prediction (CLCB-JRBS-CP). This algorithm also exploits channel modeling to predict the channel conditions of unexplored beams. Finally, we propose a Hierarchical Unimodal Upper Confidence Bound (HUUCB) algorithm to further improve the convergence of the HTS algorithm, with the assumption that each cluster's arms' expected rewards satisfy the Unimodal property. The HUUCB algorithm can be applied to a variety of problems in communications, such as optimal beam selection in mmWave links with multiple frequencies, and applications beyond communications, such as joint vehicle speed and route optimization in road navigation.
    • Geometrical Optics Restricted Eavesdropping Analysis of Secret Key Distillation and its Application to Satellite-to-Satellite Free Space Links

      Djordjevic, Ivan B.; Pan, Ziwen; Zhuang, Quntao; Tandon, Ravi (The University of Arizona., 2022)
      The quantum cryptography theoretically aims to promise unconditional information security in the physical layer against an omnipotent eavesdropper. However, such a conventional assumption of an all-powerful eavesdropper can be too strict for certain practical implementation scenarios and can be relaxed considerably. This dissertation reviews the relevant theories on secret key rate bounds, proposes a geometrical optics restricted eavesdropping model and studies secret-key distillation across a lossy and noisy quantum wiretap channel between Alice and Bob, with a separately parameterized realistically lossy quantum channel to the eavesdropper Eve. We show that under such restricted eavesdropping, the key rates achievable can exceed the secret-key-distillation capacity against an unrestricted eavesdropper in the quantum wiretap channel. Furthermore, we show upper bounds on the key rates based on the relative entropy of entanglement. Then we apply this model to the realistic secret key distillation over a satellite-to-satellite free space optics channel starting with a straightforward case where we assume a limited-sized aperture eavesdropper (Eve) in the same plane of the legitimate receiver (Bob) and determine the secret key rate (SKR) lower bounds correspondingly. We first study the input power dependency without assumptions on Bob’s detection scheme before optimizing the input power to determine lower bounds as functions of transmission distances, center frequency or Eve aperture radius. Then we calculate analytical expressions regarding the SKR lower bound and upper bound as transmission distance goes to infinity. Then we study one of Bob’s possible corresponding defense strategies in this realistic application model of secret key distillation over satellite-to-satellite free space channel in which we impose a reasonable restriction on the eavesdropper by setting an exclusion zone around the legitimate receiver. We first study the case where the eavesdropper’s aperture size is unlimited, so her power is only restricted by the exclusion zone. After that we limit Eve’s aperture to a finite size and study the case when her aperture is in the same plane of Bob, investigating how an exclusion zone can help improve security. Correspondingly, we determine the secret key rate lower bounds as well as upper bounds. We show that by putting reasonable restrictions on the eavesdropper through the realistic assumptions of an inaccessible exclusion zone, we can increase the key rate in comparison to those without and do so with relatively lower transmission frequency. In the end, we study the secret key distillation over a satellite-to-satellite free space optics channel in which we assume that the eavesdropper’s limited sized aperture can be dynamically positioned to gain advantages over the communication parties, and we determine the achievable key rate lower and upper bounds with respect to different scenarios. We first study the case where Eve is behind Bob, and we prove that the optimal eavesdropping strategy for her in long-distance transmission case is to place her aperture on the beam transmission axis and set Bob-to-Eve distance equal to Alice-to-Bob distance. We also show that the achievable key rate would be characterized by a Bessel function integral related to Eve’s position in a short-distance transmission case. We then investigate the case where Eve is before Bob and show similar results with Eve’s and Bob’s roles exchanged. For our analyses we also incorporate specific discrete variable (DV) and continuous variable (CV) protocols for comparison.
    • Evidence-Based Education on Child Maltreatment Risk Factors for Pediatric Primary Care Providers

      Carson, Sheri; Allen, Kaitlin Sarah; Peek, Gloanna; Zook, Tiffany (The University of Arizona., 2022)
      Purpose: The purpose of this quality improvement (QI) Doctor of Nursing Practice (DNP) project was to educate pediatric providers on the Safe Environment for Every Kid (SEEK) model to improve their knowledge of psychosocial risk factors for child maltreatment (CM) and support their identification of these targeted risk factors in the primary care setting. Background: Child maltreatment is a significant problem in the United States (US) that is highly preventable. Pediatric primary care providers (PCPs) are in a unique role to aid prevention efforts; however, the majority of providers do not routinely screen for CM and associated psychosocial risk factors. Key barriers to provision of CM screening and anticipatory guidance include lack of provider knowledge, training, comfort, and lack of validated and recommended screening tool. The SEEK model was created to address this gap in care and serves as an effective, evidence-based program for use in the primary care setting to educate and support providers in preventing child maltreatment. Methods: This QI project utilized pretest/posttest design with an evidence-based educational PowerPoint presentation that summarized SEEK provider training modules. Participants were pediatric PCPs from Agave Pediatrics in Arizona. The 10-question pretest survey and 11-question posttest survey contained five of the same knowledge-based questions about presentational content. Additional survey questions measured participant perception of knowledge level, as well as level of comfort assessing and addressing CM risk factors. Results: Four providers (n=4) completed the pretest survey, educational presentation, and posttest survey. Project data demonstrate that there was statistically significant (p<0.05) improvement in knowledge following educational intervention. Participants’ perception of their knowledge following educational intervention demonstrated an improvement, although not statistically significant (p=0.88). All participants agreed that educational presentation increased their levels of comfort in assessing and addressing psychosocial stressors and risk factors associated with child maltreatment. Conclusions: This DNP projected demonstrated a statistically significant improvement in provider knowledge following an educational presentation on CM and SEEK model. This project adds to current body of evidence supporting educational interventions as an effective method to improve provider knowledge of CM risk factors and associated psychosocial concerns, specifically through the utilization of the SEEK model.
    • Integrated Statistical Modeling of Engineering Data with Shared Information

      Zhou, Qiang; Ghosh, Mithun; Hao, Qing; Liu, Jian; Shafae, Mohammed (The University of Arizona., 2022)
      Data has become exceedingly important to organizations, especially with regard to decision making. The large amount of available data is crucial in engineering applications as it ensures the understanding of the problem and the efficient execution of the solution. Studies have also shown that the employment of large amounts of data in engineering applications makes it easier for the data-driven model to generate insights that can be acted on in the best interest of the optimal solution. With the existence of multiple data sources, we can unveil hidden patterns and trends to determine possible relationships in the most complex engineering applications. This has traditionally been achieved by building single statistical models independently to explain single data sources. Nonetheless, when there exists a correlation among several data sources, a single statistical model strategy has been shown to be time consuming, result in loss of pertinent information, and is tedious. It is against this backdrop that this dissertation aimed at developing statistical models that can accurately predict the responses of three important engineering applications. To achieve this aim, this dissertation developed three integrated statistical modeling (ISM) techniques for these three applications. The choosing of the techniques was informed by the fact that they have shown great performance benefits. First was the modeling of multivariate profiles. In some manufacturing processes, profile data are collected to monitor process variations. In situations when multiple profiles are collected together, correlations might exist across profiles. Modeling these multivariate profiles requires describing both within and between profile correlations. Second was the discovery of material oxides, which often suffers from data scarcity. In some cases, collecting data from the target source can be expensive, while there are auxiliary data sources that are cheaper to collect. In such situations, auxiliary data sources can be exploited to improve the performance of the expensive target data. Third was the investigation of data by grouping information where subjects are clustered into various groups. Through employment of the above strategies and applying them to examples and case studies, it was evident that improvement of the prediction accuracy can be realized by exploiting the within-group and between-group characteristics in these data sources, instead of modeling each data source separately. In general, transferring the knowledge across sources is complicated for most real-world systems, and often traditional modeling approaches are not adequate to capture the relations, when data are not stationary or are changing abruptly in a small interval. In addition, the modeling time can be burdensome with the increased number of sources and observations. Hence, developing efficient and flexible frameworks for multiple correlated data sources is imperative. This dissertation proposed novel ISM techniques to deal with the complicated scenarios associated with correlated data sources. This study further demonstrated that the proposed ISM techniques have the ability of helping to model correlation among different data sources into a single modeling framework. The major advantage of the proposed ISM methods was found to be their flexibility over individual modeling of each data sources. The study concludes by proving that it is possible to effectively handle data nonstationarity with reasonable computation loads.
    • Composite Likelihood Method for Genome-Wide and Phenome-Wide Association Studies

      Zhou, Jin; Chen, Yuliang; Hu, Chengcheng; Zhou, Hua; Klimentidis, Yann (The University of Arizona., 2022)
      With the advances in sequencing technology and wide adoption of electronic medical health records (EHR) nationally and internationally, the massive amount of genetic and phenotypic data are accessible at an affordable price. For example, common genomic variants, such as common single-nucleotide polymorphisms (SNPs), can be measured by the commercial SNP chip for under $100 per sample (Weedon et al., 2021). In addition, disease diagnosis codes (e.g., International Statistical Classification of Diseases (ICD) code) and lab measures stored in EHR allow deep phenotyping. Therefore, we are better equipped to identify associations between human genetic variations and diseases. However, as the sample sizes of current genetic studies have increased exponentially, there is a greater demand for efficient analytical tools that are scalable to ultra-large sample sizes and can simultaneously adjust for confounding factors. In this dissertation, I develop a suite of approaches based on composite likelihood framework to handle the sample relatedness and imbalanced case-control proportions for biobank scale genetic association studies. Linear mixed-effect models (LMM) are commonly used to model the sample relatedness (i.e., polygenic background). In the first project, we introduce the composite likelihood approach to the LMM. Using the composite likelihood, we avoid inverting the huge covariance matrix and reduce memory usage in genome-wide association study (GWAS). We first estimate the variance components in the LMM by the method of moments (MOM) and stochastic gradient descent (SGD) algorithms. Second, we derive Wald and score tests for testing the association between a single SNP and a continuous phenotype. Our method divides the entire high-dimensional correlated data into multiple one-dimensional data and then solves the problem by combining the information from many one-dimensional data. The simulation studies indicate that the memory usage for estimating variance components is substantially reduced compared to the existing methods. Notably, using our approach, millions of tests can be distributed to multiple clusters and evaluated simultaneously. It is known that the diagnosis codes in phenome-wide association study (PheWAS) may be inaccurate and rare (i.e., imbalanced case-control proportions). Both lead to biased results. In the second project, we aim to address this problem by taking advantage of multiple correlated diagnosis codes and their ontology. The composite likelihood approach and the generalized estimating equation (GEE) are applied. First, the SNP effect is estimated by GEE in the composite likelihood framework. Second, the corresponding Wald test statistics are derived for testing the association. Our methods use two-dimensional correlated phenotypes to capture the characters of higher dimensional correlation structures between diagnosis codes. Simulation studies reveal that the type I error of this approach is well controlled, comparable power to the traditional GEE, and much more powerful than the existing PheWAS tools. In the third project, we apply our methods to the UK Biobank study. We implement several existing methods for the GWAS and PheWAS analysis and compare the analysis results between these methods. The GWAS results are consistent between our methods and the existing methods. The PheWAS results of our novel approach are more potent than that of the traditional methods and are supported by the current literature.
    • Information-Seeking, Online Search Tools, and the Formation of New Norms in Health Behaviors during the Covid-19 Pandemic

      Breiger, Ronald L.; Gonzalez, Kelsey Elizabeth; Martinez, Daniel E.; Abramson, Corey M.; Shmargad, Yotam (The University of Arizona., 2022)
      This dissertation focuses on how people search for information and how people rely on this information to inform their health behaviors and develop social norms. In academia and policy, the focus in research on information has most often studied the information that is sent to consumers, seeing people as passive receivers of information. This is otherwise known as information 'push'. But, information is also intentionally sought out by individuals; called information pull. My dissertation focuses on individuals as active agents in their search for information and how the information discovered through these push and pull processes relates to the creation of social norms. My first article tests the criterion validity of Google Search Trends as an indicator of computer-mediated information search. I attempt to validate Google Search Trends for use as indicators of attitudes, disease prevalence and political preferences using five different data sources. My analysis revealed no correlation among any of the Google Trends tested and their validated indicators. I demonstrate that there is no criterion validity of Google Trends for the selected cases and social scientists will find no replacement for high quality survey data with Google Trends. Instead, we must only use Google Trends to demonstrate interest or attention. Knowing that Google Trends data only encompasses a small portion of the information-seeking done by modern humans, my second article is motivated by the research question: How do computer-mediated or interpersonal information-seeking strategies vary across populations? Using original survey data of 948 Americans, I investigate their experiences seeking out information about COVID-19 vaccines. I investigate five distinct information seeking modalities, or methods of searching for information: personal connection, doctor, social networking site, online forum, and online search engine. I find that different exposure points, the ways people first are exposed to information without searching for it, and information search modalities hold real world consequences through their associations with COVID-19 vaccinationintentions and rates. For example, I find that receiving or seeking out information from a doctor increases COVID-19 vaccination uptake while receiving information from a social networking site is associated with lower odds of vaccination. My final article takes a deeper dive into the formation of social norms governing health behaviors in cases of extreme uncertainty. I specifically use the cases of stay-at-home rates and vaccination rates as responses to public health recommendations to mitigate the COVID-19 pandemic. Using the theories of associative diffusion and the integrated theoretical framework of norms, I test models of behavioral adaption to public health recommendations and patterns of complex contagion (the need for repeated exposures to something novel for it to diffuse) using linear mixed effects models. My results show that complex contagion is a valid framework for the social contagion of new norms during COVID-19. However, I find an important novel moderating effect of signal discordance; if there is diversity in the information received by an ego, contagion is less likely to occur. This paper shows that the contagion process is not fully understood without looking at the context of each exposure to a contagion within the range of contagions one experiences. The introductory chapter provides a summary of the research and an explanation of how this research contributes to sociology, social science, and society. Namely, this paper provides important perspectives on search as an agentic process and how the micro-level information seeking process of an individual can lead to macro-level social norms. I show that information diffusion is disrupted when conflicting information and behaviors are simultaneously diffusing and therein contribute to research on diffusion, social networks, and social norms.
    • Online MBA Rankings: The Impact of Rankings on Online MBA Programs

      Rhoades, Gary D.; Jorden, Pamela; Milward, H Brinton; Lopez, Jameson D. (The University of Arizona., 2022)
      This study analyzed the effect that shifts in the U.S. News & World Report rankings have on input variables such as admitting grade point average (GPA), percentage of students taking the Graduate Management Admissions Test (GMAT), average incoming GMAT score, acceptance rate, tuition rates, average student debt, the proportion of students with debt, the number of tenure track faculty and the percentage of minority students. Finally, this study will examine if these correlations are more pronounced during the initial years of this ranking regime or in the most recent years. This is not the first study to look at U.S. News & World Report business school rankings, but it is the first study to specifically look at online business school rankings. The study determined rankings influence admissions criteria and the number of tenure track faculty. Implications of this finding for further research and practical implications for administrators are discussed, and the study's limitations.
    • Postmodern Realism in Late Twentieth and Early Twentieth-First Century Anglo-American Fiction

      Selisker, Scott; Chabko, Wioletta Anna; Lempert, Manya; Srinivasan, Ragini (The University of Arizona., 2022)
      This dissertation discusses examples of Anglo-American realist fiction from the end of twentieth and the beginning of twentieth-first century. Since the 1990s, literary scholars have been acknowledging a waning of postmodernism as a literary aesthetic. Amidst the succeeding post-postmodern developments in literary fiction of the last few decades, there appears to be an increased interest in literary realism’s forms, techniques, and thematic concerns. This diachronic study argues that literary realism has been a strong current in Anglo-American fiction even at the peak of postmodern literature’s heyday; this dissertation traces realism’s recalibration through the influence of postmodern aesthetic and cultural phenomena beginning with Joan Didion’s late 1970s’ work, continuing through the late 1990s and the late David Foster Wallace’s writing, and, finally, an early twentieth-first century novel by Zadie Smith. The goal of this dissertation is to elucidate the ways in which these prominent writers from the Anglo-American literary tradition negotiate their relationship with postmodernism via realism-associated forms, techniques, and thematic concerns.
    • Competitive Threats in Mating and the Workplace: Intra and Inter Sexual Competition

      Figueredo, Aurelio J.; Zambrano, Rachel Christine; Davis, Melinda; Stelkis, Horst; Edgin, Jamie (The University of Arizona., 2022)
      Throughout human evolution, Homo sapiens have engaged in competition for mates and competition for status, which may translate into differential access to resources. Much research has been conducted on the psychological mechanisms that underlie competitive behavior, yet no research has investigated what traits contribute to another individual, or rival, being considered a competitive threat. The goal in this research is to identify the factors that contribute to an individual being considered a competitive threat in a mating context and a work context and to see how biological, ecological, and personality variables influence an individual’s perception of these factors. We found that being a Dating Threat was the number one predictor (sR = .52, p <.001) of an individual being considered a Working Threat. This suggests that there is overlap in the traits that constitute an individual being evaluated as a competitive threat in the dating and working marketplaces. Employee Turnover was not significantly predicted by the presence of a Dating Threat or Working Threat but was significantly predicted by Indirect Aggression (sR = .14, p = .01) and Direct Aggression (sR = .15, p = .004). Further research and replication are needed to fully flush out the traits that contribute to an individual being considered a competitive threat.
    • The Performance of Refugeehood on Social Media in an Era of Superdiversity: A Digital Ethnographic Study of Arab Refugee Identities and Literacies on YouTube

      Gilmore, Perry; Elsayed, Ahmad; Combs, Mary Carol; Tardy, Christine (The University of Arizona., 2022)
      The internet has increased the visibility of cultures and subcultures that would otherwise remain invisible (Varis & Wang, 2011). This study explores the post-migration identities and literacy practices of one such subculture, namely Arab refugees resettled in Europe, by taking a close look at their social media presence and activism in a superdiverse setting. Using digital ethnography as a methodology, and drawing upon various theoretical perspectives, including notions from Mikhail Bakhtin, Erving Goffman, and Pierre Bourdieu, the study analyzes YouTube videos by two refugee YouTubers from Syria, who have been resettled in Germany and Sweden. By investigating their use of language and other semiotic resources on the social media platform, the aim is to gain insight into their identity performance (Jonsson & Muhonen, 2014) and how they reflect superdiverse conditions. The study builds on a growing body of research exploring superdiversity in digital contexts (e.g., Androutsopoulos & Juffermans, 2014; Stæhr, 2015; Varis, 2017; Varis & Blommaert, 2015). However, two aspects remain largely unaddressed in the literature: the resettlement experiences of Arab refugees as creators of digital content and an explicit examination of power and social justice issues, two gaps this study attempts to fill.
    • L1 and L2 Phonological Awareness in Adults

      Bunton, Kate; Wedel, Andrew; Hafner, Florian; Warner, Natasha (The University of Arizona., 2022)
      This study investigated English phonological awareness in adult native speakers of English (L1) andin relation to their phonological awareness skills and proficiency in their German (L2). Most research in L1 phonological awareness focuses on younger children, their phonological awareness development, the relationship between reading and phonological awareness, as well as disorders. Little is known about adults and their phonological awareness skills. Most often, adults are used as controls without further investigation. In cases where phonological awareness has been investigated in adults, it was mostly special populations such as poor readers, speech-language pathologists, or low literacy or illiterate adults. This study investigated adults L1 phonological awareness skills in English with tasks such as rhyming, segmenting, identifying, replacing, deleting, and reversing; a mispronunciation task was also included. Results show that while all tasks but segmenting and rhyming are close to ceiling, segmenting and rhyming exhibit great variability. Some individuals also showed below average performance on the other tasks, indicating that there is variation in adult L1 phonological awareness. The same adults were tested during their second semester of learning German, with the same tasks in German. The relation between their L1 and L2 phonological awareness skills was strong and significant. More interestingly, the segmenting and reversing task were more accurate in the subjects’ L2, possibly due to the shallower orthography of German. Finally, participants’ L2 proficiency was assessed with a C-Test. Results demonstrate a significant relation between the L2 phonological awareness skills and the L2 proficiency, despite the proficiency measure being one that more heavily focuses on grammar and vocabulary and not so much on pronunciation or sounds in general.
    • Decision Making in Competitions

      Noussair, Charles N.; Rhee, Elaine; Woutersen, Tiemen; Kugler, Tamar; Romero, Julian (The University of Arizona., 2022)
      This dissertation consists of three distinct papers (chapters) that explore various factors that affect one's decision making in a competitive environment and whether or not gender differences exist in such decision making by conducting experiments. Competitions are ubiquitous. Athletes compete with each other to win a championship. Everyone in the labor market compete with each other for a job offer or promotion. Firms compete with others to get a higher market share or profit. Moreover, it has been shown that many types of gender differences exist in competitive environments (Niederle and Vesterlund, 2007; Bertrand and Hallock, 2001; Vallerand and Reid, 1988; Shurchkov, 2012). In particular, we study how prior interaction with a competitor and whether or not observing that the majority of the audience bet on an individual to win influences one's competitiveness and performance. In addition, we test if gender differences exist in how the two factors affect one's competitiveness and performance. Furthermore, we examine how self-promoters cooperate when the ability varies among teammates and teams. In the first chapter, we test whether men and women differ in their willingness to challenge a competitor in response to a prior transgression. A laboratory experiment is conducted, in which a player can choose to behave unfairly toward another. The other player may then challenge the first to a contest. We investigate the extent to which previous interactions can explain individual differences in tournament initiation decisions. The results show that men, but not women, tend to challenge a competitor more when the prior outcome is unfair and the unfairness occurred through the competitor's intentional choice. In contrast, unfair outcomes that occur by chance do not influence the decision to challenge others. The second chapter investigates the impact of sports betting legalization on players’ competitiveness and performance. In particular, lab experiments are used to examine how tournament entry decisions are affected when players are exposed to the betting odds, such as favorite and underdog. One experimental treatment had a betting market that did not reveal the betting results to the players, and the other had a betting market that did reveal the betting results to the players before the competition. The results show that the favorites and underdogs behave the same when the betting results are not revealed, but the favorites enter tournament significantly more than the underdogs when the betting results are revealed. This is especially the case for male leagues. Moreover, the favorites win the game significantly more than the underdogs only when the betting results are revealed. In the third chapter, we test whether having a higher ability player on one's team or an opposing team affects limelight-seekers' cooperation. A laboratory experiment is conducted, in which two teams compete for a team competition cash prize, and teammates compete for an individual competition cash prize. We investigate how the magnitude of the ability gap can explain individual differences in cooperation. The results show that players cooperate less when competing with a team that has a player with higher ability and the ability gap is great. However, the cooperation decisions of the teammates of the players with higher ability is not dependent on the magnitude of the skill gap.
    • A Quantum Stochastic Approach to Poisson Master Equation Unravellings and Ghirardi-Rimini-Weber Theory

      Wehr, Jan; Keys, Dustin Michael; Kennedy, Tom; Sethuraman, Sunder (The University of Arizona., 2022)
      The theory of quantum stochastic calculus is used to expand the traditional Ghirardi-Rimini-Weber theory to a fully quantum theory, where the noise can be then be interpreted as a new field interacting with quantum systems. A derivation of a stochastic unravellling of the GKSL master equation is first presented from the standpoint of a purely quantum theory, which is then specialized to the case of the GRW master equation. Reverse engineering this procedure gives rise to a new nonlinear quantum stochastic wave equation which preserves a generalized system norm and is an unravelling of the GKSL master equation. Comments on how this particular interpretation can be tested are given.
    • Generalizing Bondal-Orlov Criteria for Deligne-Mumford Stacks

      Hall, Jack; Priver, Kyle Jamison; Joshi, Kirti; Pickrell, Doug; Levin, Brandon (The University of Arizona., 2022)
      If $F:D^{b}_{coh}(\mathcal{X}) \to T$ is a functor with left and right adjoints from a proper smooth Deligne--Mumford stack with projective coarse moduli space to a triangulated category, there is a Bondal--Orlov criterion determining the full-faithfulness of $F$. We develop techniques that allow for the proof of this criterion absent the assumption that the course moduli space of $\mathcal{X}$ is projective. Furthermore, if the functor $F$ has a dg or infinity category enhancement, the assumption that $F$ has left and right adjoints may also be relaxed.
    • Electronic Cigarettes: Anesthetic Considerations to Improve Clinical Practice

      Reel, Sally J.; McMillan, Lee Aaron; Herring, Christopher; Reed, James (The University of Arizona., 2022)
      Purpose. The purpose of this quality improvement project was to develop and present an educational video presentation to anesthesia providers regarding anesthetic considerations for patients who use electronic cigarettes, and to assess whether the educational presentation causes a change in the anesthesia providers’ attitudes, knowledge, confidence, and intent to change clinical practice. Background. The prevalence of electronic cigarette use has been increasing, especially among adolescents and young adults. Research findings have associated electronic cigarette use with multiple adverse health effects that should be considered when providing anesthetic care to these patients. Anesthesia providers may not be fully informed about these effects and may not be adequately screening patients for electronic cigarette use prior to surgery. Methods. Participants were instructed to take a pretest survey, view a pre-recorded educational presentation, and then complete a posttest survey. The surveys were intended to assess for changes in anesthesia providers’ self-reported attitudes, knowledge, confidence, and intent to change clinical practice before and after viewing the presentation. Results. Three out of 25 anesthesia providers participated in the project. All participants reported improved attitudes towards the importance of anesthetic considerations for electronic cigarette users, increased knowledge, increased confidence in caring for patients who use electronic cigarettes, and a positive intent to include questions about electronic cigarette use when interviewing patients preoperatively as well as to incorporate the anesthetic considerations described in the educational presentation in their clinical practices. Conclusions. Although the survey results showed changes had occurred in the outcome measures, due to the limited sample size no conclusions could be drawn.
    • Fantasies of Ambivalence: Romance and Historical Consciousness in Eighteenth-Century Britain

      Hogle, Jerrold E.; Brown, Meg Lota; Chronister, Kay; Hurh, Paul; Thell, Anne (The University of Arizona., 2022)
      “Fantasies of Ambivalence: Romance and Historical Consciousness in Eighteenth-Century Britain” examines the relationship between romance and partisan history-writing in Britain following the English Civil War and 1688 Revolution. Considering works of fiction by Delarivier Manley, Marie-Catherine d’Aulnoy, Horace Walpole, Ann Yearsley, and Walter Scott alongside works of traditional historical and political discourse, this dissertation argues that that historical romance maintained a continuously evolving literary presence in eighteenth-century Britain. During this period, the quintessentially romantic formal characteristics of anachrony, structural repetition, function-driven narrative, and complex allegory reappeared across multiple genres, including the keyed secret history and the Gothic novel, each of which may be considered a form of “historical romance” and each of which played their own roles in meditating British consciousness of the relationship between past and present. The formal characteristics of historical romance made it exceptionally able to register conflicting viewpoints, sentiments, or beliefs simultaneously without subordinating one to the other or otherwise reconciling them. In many cases, writers deployed this capability to act as the handmaidens of political ideology, using romance forms to conceal the contradictions or fissures in partisan visions of the British past. Yet, in certain cases, writers of historical romance also acted as challengers to ideology, exposing those contradictions and fissures. Increasingly, as the hyper-partisanship of the early eighteenth century yielded to the doubts of the mid-century and the disenchantment of the 1790s, historical romance served more as a mechanism of ideological critique than of partisan reinforcement. I track this shift by observing the transition from the literary predominance of the keyed secret history in the early eighteenth century to that of the palimpsestic neo-Gothic romance in later decades, a transition which saw the replacement of romance’s long-standing historiography of fantasy by a historiography of fantasy echoes.