More than 30,000 theses and dissertations produced at the University of Arizona are included in the UA Theses and Dissertations collections. These items are available open access, and are full-text searchable. A small percentage of items are under embargo (restricted).

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 email us at

You can also refer to the Dissertations and Theses in the UA Libraries guide to find materials that are not available online.

Collections in this community

Recent Submissions

  • Development of Bioanalytical Assays Using Scintillant Polymer-Core Silica-Shell Nanoparticles

    Mokhtari, Zeinab (The University of Arizona., 2018)
    Ideal nanosensors of biomolecules are sensitive, selective, stable, minimally invasive, amenable to mass production with low-cost, and applicable for reproducible in vitro and in vivo analyses. The nano scintillation proximity assay (nanoSPA) presented here is based on a composite architecture of polystyrene-core and silica-shell nanoparticles, with a high surface area to volume ratio (ca. 2×107 m-1) and density of approximately 1.6 g/cm3. nanoSPA obviates the need for separation of bound from free radiolabeled molecules prior to measurements, with minimized complexity and maximized versatility. Selected β-emitter radioisotopes were utilized for the development of radioassays for analysis of biological processes using nanoSPA. 35S was employed for thiol/disulfide ratio analysis for the first time. Thiolresponsive nanoSPA was used for quantification of 33S-cysteine and 33S-cystine as models of 35S-thiol and 35S-disulfide. Synthetic samples of 33S-cysteine and 33S-cystine and human embryonic kidney (HEK293) cell lysates were analyzed using thiolresponsive nanoSPA for evaluation of thiol/disulfide ratio as a measure of redox status of the sample. Limit of detection for 35S-thiol analysis was <1.1 pM (<1.1 nCi) with a signal to background ratio over 10-fold. 33P-labeled adenosine triphosphate (ATPγ33P) was utilized for the development of kinase activity assays. Three nanoSPA platforms were developed for kinase activity analysis including adsorption, binding, and immuno-nanoSPA that respond based on electrostatic non-specific adsorption, covalent binding, and antibody-antigen binding, respectively. Signal to background ratio up to 24 was observed using separation-free analyses with nanoSPA, compared to approximately 11.5 using liquid scintillation analysis after many washing steps. 3H emits the lowest energy β-particles and it was utilized with nanoSPA for development of saccharide sensors. Dynamic binding of 3H-D-glucose to nanoSPA functionalized with several monoboronic acids (monoBAs) and diboronic acids (diBAs) was evaluated. The signal to background ratio was up to 2.2-fold that must be improved. Further platforms may be developed based on phospholipid-nanoSPA with minimal nonspecific adsorption and more specificity.
  • Aquatic and Riparian Connectivity in Arid Landscapes

    Sharma, Akanksha (The University of Arizona., 2018)
    Aquatic and riparian ecosystems are of critical importance in arid environments, supporting a diverse suite of resident and migratory species over different life stages. Ecological connectivity is an important property in the functioning of these ecosystems, and a significant subject of interest for researchers,scientists,resource managers, practitioners and other stakeholders. Furthermore, a variety of perceptions exists on aquatic and riparian connectivity among stakeholders, and connectivity of these ecosystems in arid landscapes is a relatively unexplored subject. I focused on these issues in the US portion of the Madrean Archipelago by combining qualitative methods to capture the diversity of perspectives among experts and quantitative spatial analysis to capture the variety of factors that influence aquatic and riparian connectivity. I synthesized the resultant expert perspectives into a Connectivity Component-Dimension Framework that deconstructs aquatic and riparian connectivity into connectivity components and their dimensions. Using GIS and regression analysis, I applied this framework to a case study of the threatened Chiricahua leopard frog (Rana chiricahuensis) in the Cienega Creek basin in Arizona and created connectivity indices for this focal species. Some factors that emerged significant in this case study included elevation, fire hazard potential, and density of leopard frog sightings. This connectivity framework and the related indices provide customizable options for stakeholders to assess aquatic and riparian connectivity multidimensionally using readily available data. These tools can be used by stakeholders for exploratory analysis, assessment and visualization of aquatic and riparian connectivity, in arid landscapes, and beyond.
  • Impact of Geographic Variation, Disability, Socioeconomic Status and Risk Adjustment on High-Risk Medication Use among Elderly Medicare Beneficiaries

    Chinthammit, Chanadda (The University of Arizona., 2018)
    BACKGROUND Inappropriate medication use is common and represents a substantial clinical and economic burden in the United States (US). The Center for Medicare and Medicaid Services (CMS) has adopted one of the Pharmacy Quality Alliance (PQA)’s quality measures to assess percentages of older adult beneficiaries receiving high-risk medications (HRM) in Medicare Advantage Prescription Drug plan and stand-alone Prescription Drug plan. Understanding geographic patterns of HRM use may help CMS and their partners develop and tailor prevention strategies (such as prior authorization) to be implemented in the areas of need. Furthermore, The HRM use measure was used to assess Medicare Advantage Prescription drug plan (MA-PD) and stand-alone Prescription Drug plan (PDP) performance and to provide guidance for practitioners to reduce the use of such medications. Limited evidence exists on how HRM use is associated with patient characteristics and whether risk adjustment is necessary to accurately evaluate health plan performance on the HRM measure. OBJECTIVES The overall objectives of this research were to understand regional and patient characteristics associated with HRM use measure to develop a risk adjustment model for the HRM measure to accurately evaluated health plan performance. The first specific aims were to examined HRM use patterns among Medicare beneficiaries enrolled in: (1) Medicare Advantage prescription drug plans (MA-PDs); and (2) stand-alone prescription drug plans (PDPs) across geographic areas over time in the United States. The second specific aims were to: (a) measure HRM use in MA-PD and PDP beneficiaries with disadvantaged characteristics, including low income and disability; and (b) examine the relationship between disadvantaged characteristics and HRM use given constant effect of health plans. The third specific aims were to examine the relations between patient risk factors and the HRM measure and develop risk adjustment tool for the HRM measure in older adults enrolled in MA-PDs and PDPs. METHODS This cross-sectional study used a 5% national Medicare sample (2011–2013 for the first aims and 2013 for the second and third aims). Among beneficiaries aged ³65 years who were continuously enrolled in MA-PDs or PDPs (~1.3 million each year), we identified those with ≥2 prescriptions for the same HRM (e.g., amitriptyline) during the year based on the HRM list provided by CMS and Pharmacy Quality Alliance. For the first specific aims, multivariable logistic regression was used to estimate adjusted annual HRM use rates across 306 Dartmouth Atlas of Health Care hospital referral regions (HRRs), adjusting for sociodemographic, health-status, and access-to-care factors. For the second aims, Multivariable generalized linear mixed models were used to assess the association of HRM use and disadvantage factors such as low-income subsidy (LIS)/dual eligibility status (DE) and disability after adjusting for health plan effect and patient-level confounding characteristics (i.e., sociodemographic, geographic, clinical complexity). For the third aims, multivariable generalized linear mixed models were used to assess the association of HRM use and patient risk factors (e.g., age, gender) and identify risk factors after adjusting for health plan effect. The identified risk factors were used as variables for regression-based risk adjustment for the HRM measure. Unadjusted and adjusted quality rankings among health plans were compared. RESULTS First, a total of 1,161,076, 1,237,653, and 1,402,861 beneficiaries satisfied the study criteria and were included in 2011, 2012, and 2013, respectively. Among our study sample, nearly 40% (39%, 39% and 37% in 2011, 2012 and 2013 respectively) were enrolled in MA-PD plans, whereas remaining 60% (61%, 61%, and 63% in 2011, 2012 and 2013 respectively) were enrolled in PDP plans. HRM use significantly decreased over time among Medicare beneficiaries enrolled in MA-PD (13.1% to 8.4%, p<0.001) and PDP (16.2% to 12.2%, p<0.001) plans. Among MA-PD beneficiaries, HRM users more frequently: female (70.4% vs. 59.9%, p<0.001); White (84.6% vs. 81.4%, p < 0.001); eligible for the Part D Low Income Subsidy or Medicaid benefits (22.3% vs. 16.6%, p<0.001); and disabled (15.6% vs 8.7%, p<0.001) compared to non-HRM users in 2013. Among PDP beneficiaries, HRM users had higher proportions of: females (72.8% vs. 62.5%, p < 0.001); Whites (86.6% vs. 85.3%, p<0.001); LIS/DEs (29.2% vs. 23.3%, p<0.001); and disabled people (15.4% vs 8.5%, p<0.001) compared to non-HRM users. In 2013, the ratios of 75th-to-25th percentile HRM use rates across HRRs were 1.42 (MAPDs) and 1.31 (PDPs). HRRs with the highest HRM use rates were: Casper, WY (20.4%), Waco, TX (16.7%), Lubbock, TX (15.7%), Santa Barbara, CA (15.2%), and Temple, TX (15.1%) (MA-PDs); and Lawton, OK (18.8%), Alexandria, LA (18.8%), Lake Charles, LA (18.6%), Oklahoma City, OK (18.0%), and Slidell, LA (18.0%) (PDPs). Second, there were a total of 520,019 MA-PD and 881,264 PDP beneficiaries who met the study criteria. Of the MA-PD beneficiaries, 88,693 (17.1%) were LIS/DE and 48,997 (9.4%) were disabled. Of PDP beneficiaries, 213,096 (24.2%) were LIS/DE, and 83,593(9.5%) were disabled. LIS/DE beneficiaries had a higher percent of HRM users compared to non-LIS/DE MA-PD (17.0% vs. 9.6%, p < 0.001) and PDP (17.1% vs. 13.2%, p < 0.001) beneficiaries. Disabled beneficiaries had a higher percent of HRM users compared to non-LIS/DE MA-PD (17.0% vs. 9.6%, p < 0.001)) and PDP (17.0% vs. 9.6%, p < 0.001) beneficiaries. Multivariable analyses showed LIS/DE (OR = 1.07; 95% CI: 1.04, 1.10) and disability (OR =1.38; 95% CI: 1.34, 1.42) were associated with HRM among the MA-PD population as well as in the PDP population (LIS/DE OR = 1.14; 95% CI: 1.12, 1.16 and disability OR = 1.37; 955 CI: 1.34, 1.40). Third, the HRM users were more likely to be younger (OR = 0.981, 95% CI, 0.980-0.983 for MA-PD and OR=0.982, 95% CI, 0.981-0.983 for PDP); women (OR = 1.545; 95% CI,1.514-1.576 for MA-PD and OR=1.606, 95% CI, 1.584-1.628); eligible to receive low-income subsidy (OR = 1.086, 95%CI, 1.057-1.115 for MA-PD and 1.170, 95% CI, 1.150–1.190 for PDP); disabled (OR = 1.380, 95%CI, 1.342 –1.420 for MA-PD and 1.378, 95%CI, 1.352–1.405 for PDP); seeing multiple prescibers (OR =1.076, 95%CI, 1.072, 1.081 for MA-PD and 1.072, 95%CI, 1.069-1.075); filling prescriptions at multiple pharmacies (OR = 1.092, 95%CI, 1.083-1.102 for MA-PD and OR = 1.092, 95%CI, 1.086, 1.099 for PDP); and had higher average modified RxRisk-V (OR = 1.176, 95%CI ,1.171 – 1.181 for MA-PD and OR = 1.173, 95%CI, 1.170-1.176 for PDP). Being older and white were protective against receipt of HRMs. These variables were recommended for the risk adjustment model. Unadjusted scores showed low levels of agreement (Cohen’s kappa < 0.7) with risk-adjusted scores in identifying statistical outliers suggesting risk adjustment is necessary. CONCLUSION Geographic variation in HRM use exists among older adults in Medicare, regardless of prescription drug plans. Areas with high HRM rates may benefit from targeted interventions to prevent potential adverse consequences. LIS/DE; disability; demographic such as age, gender, race; and clinical complexity were associated with higher HRM use in both the MA-PD and PDP populations even when controlling for health plan effects. Failure to adjust for beneficiaries case mix might penalize some truly high-quality MA-PD and PDP providers that serve sick beneficiaries or beneficiaries with poor socioeconomic conditions.
  • Examining Three Levels of Social Integration and Health in Minorities: A Bioecological Perspective

    Flores, Melissa Ann (The University of Arizona., 2018)
    Background. Understanding and dismantling health disparities remain one of the most essential imperatives for our nation. The complexity of interacting sociodemographic and structural factors affecting health is difficult to quantify. Thus, sophisticated approaches which take into account not only an individual but their dynamic, social environments are necessary for understanding resiliency and strengths in these populations (Thornton et al., 2016). In this dissertation, I adopted a developmental perspective (e.g. Bioecological Theory) that may guide scientists when considering several interacting, sociocultural environmental factors at once. Social integration is a powerful force in an individual's life. Although 'social integration' may have many names (perceived social support, closeness of social ties, diverse social networks, etc.), broadly, it is accepted that one's social life has a profound impact on their corresponding health and mortality through various behavioral and physiological pathways (Holt-Lunstad, Smith, & Layton, 2010; Robles & Kiecolt-Glaser, 2003; Symister & Friend, 2003). Thus, any comprehensive study on health should include a broader investigation of socio-environmental variables including measures of social integration and broader community culture and resources. Historically, however, investigations focused on social integration, physical health, and the association between the two have traditionally underrepresented minority individuals (Heiat, Gross, & Krumholz, 2002; Hussain-Gambles, Atkin, & Leese, 2004; Murthy, Krumholz, & Gross, 2004). Research Aim and Questions. Adopting a social-ecological systems approach, the focus of my dissertation is to examine social integration at three levels (the spousal/partner relationship, immediate family-level dynamics, and neighborhood and community level factors) and the association of these levels of social integration with the health of minority individuals (Bronfenbrenner & Evans, 2000; Bronfenbrenner & Morris, 1998, 2007). I addressed this aim through three, separate research questions (RQ)/Chapters: RQ1/Chapter II) The individual and spousal/partner relationship, What are the associations between marital status and social support with health quality of life (HQoL), and mortality in post-menopausal, Hispanic women? RQ2/ Chapter III) Immediate family-level dynamics, Does synchrony of emotional arousal in diverse families facing breast cancer predict depressive mood and coping style in breast cancer patients? RQ3/ Chapter IV) Neighborhood and community level factors, Do social ties or social support mediate the ethnic density effect for Hispanics and other racial-ethnic groups? Methods and Data Sources. Three distinct data sources were examined within this body of work. In Chapter II, I utilized data from the Women's Health Initiative, Observational Study (Anderson, et al., 1998). In this analysis, I examined the relation between marital status and two outcomes: mortality and health quality of life. I also assessed whether the relations between marital status and these outcomes were attenuated or moderated by social support and language acculturation. In Chapter III, I utilized data collected for The Family Coping and Breast Cancer Project which recruited patients during the years of 1991 – 1993 (Weihs et al., 2005). In this analysis, I examined emotion arousal synchrony among family members (patient and spouse, and patient and child) using cross recurrence quantification analysis. I then examined whether the relations between emotion arousal synchrony and two breast cancer patient outcomes (coping style and depressive mood) are moderated by patient perceived family environment ratings or race. Lastly, in Chapter IV, I analyzed data from Wave 2 of the National Social Life, Health, and Aging Project (O’Muircheartaigh, English, Pedlow, & Kwok, 2014). In this analysis, I examined whether the Hispanic ethnic density effect was mediated by either social network variables (size, closeness of ties, and diversity) or social support and whether these associations were moderated by Hispanic ethnicity. Results. In the first study (Chapter II) I found that marital status was a significant predictor of mortality for older Hispanic women. Specifically, widowed women had significantly higher mortality risk when compared to their married counterparts. This relation, however, was not present after controlling for social support and language acculturation. In regard to health quality of life, marital status was associated with physical functioning, with widowed women reporting significantly worse physical functioning three years after baseline when compared with their married counterparts. This study suggests that widowed, Hispanic women may be at risk for poor health and this may be facilitated through social support and language acculturation. In the second study (Chapter III) I found that the relation between emotional arousal synchrony and patients' depressive mood in families facing breast cancer was moderated by family environment, specifically conflictual environments. I also found that the relation between emotional arousal synchrony and coping style was moderated by family environment, specifically for cohesiveness ratings. Moderation by race was not found. These results suggest that emotion arousal synchrony are family dynamics that may have differing implications depending on the family environment. In the third study (Chapter IV) I found two Hispanic ethnic density effects, but they were not mediated by social network variables. However, they were mediated by social support, but not in the direction I hypothesized. Social support was an inconsistent mediator of the relation between ethnic density and depressive symptoms and a suppressor of the relation between ethnic density and morbidity. These results suggest that for all racial/ethnic groups, ethnically dense neighborhoods do not beget higher social ties and social support. Conclusions. Overall, findings in this dissertation suggest that varying levels of the social-ecological environment are associated with health in minorities in various ways. A common phenomenon that arose in all three analyses were questions about how covariates or mediators influenced the association of the main variable of interest and its relation to different health outcomes. Broadly, this may be a common issue for social scientists interested in utilizing social variables from different social-ecological levels (micro-system, exosystem, etc.), which corroborates my previous statement regarding the complexity of social environments.
  • Effects of Stress, Sleep Hygiene, and Exercise on Academic Engagement in Undergraduate Students

    Nelson, Audrey (The University of Arizona., 2018)
    Academic engagement is important for the scholastic outcomes of college students, including degree completion. The current study examined the relations between stress and the intrinsic aspects of academic engagement (e.g. effort, attention, note-taking, attendance, asking for help, etc.), including the four factors of undergraduate engagement as outlined by Handelsman, Briggs, Sullivan, & Towler (2005): Factor 1 – “skills engagement,” Factor 2 – “emotional engagement,” Factor 3 – “participation/interaction engagement,” and Factor 4 – “performance engagement,” in addition to the mediating/moderating properties of the self-care practices of sleep hygiene and physical activity. Intrinsic versus extrinsic engagement was evaluated in this study as it is believed this approach affords more opportunities for subsequent interventions since they can be implemented in an individual or small group setting, and not be constrained by the challenges of making large institutional changes. The sample consisted of 203 undergraduate students from a large southeastern university. Results indicated that stress was negatively correlated with the factor of academic engagement most related to executive functioning (i.e. skills engagement). Of the independent variables evaluated, sleep hygiene showed the strongest correlations with academic engagement, most specifically for the skills engagement and performance engagement factors. Sleep hygiene also functioned as a mediator in the relationship between stress and the skills factor of engagement, resulting in a 47% reduction in the effect of stress. Exercise did not show correlations with any areas of engagement, but did show a small interaction effect on the relationship between stress and the academic engagement factor of participation/interaction. Stress was seen to have a positive impact on participation/interaction engagement. A moderating effect of physical activity was identified, leading to lower participation/interaction engagement when both stress and exercise were high. Exercise, ethnicity, age, class rank, and gender did not add predictive ability to any of the models for academic engagement/factors of engagement. These results highlight the potential benefits of improving sleep habits and promoting programs aimed at minimizing and addressing stress (e.g. meditation, mental health supports) in order to promote success and positive academic outcomes in undergraduate students. Directions for future research were also discussed.
  • Machine Reading for Scientific Discovery

    Hahn-Powell, Gus (The University of Arizona., 2018)
    The aim of this work is to accelerate scientific discovery by advancing machine reading approaches designed to extract claims and assertions made in the literature, assemble these statements into cohesive models, and generate novel hypotheses that synthesize findings from isolated research communities. Over 1 million new publications are added to the biomedical literature each year. This poses a serious challenge to researchers needing to understand the state of the field. It is effectively impossible for an individual to summarize the larger body of work or even remain abreast of research findings directly relevant to a subtopic. As the boundaries between disciplines continue to blur, the question of what to read grows more complicated. Researchers must inevitably turn to machine reading techniques to summarize findings, detect contradictions, and illuminate the inner workings of complex systems. Machine reading is a research program in artificial intelligence centered on teaching computers to read and comprehend natural language text. Through large-scale machine reading of the scientific literature, we can greatly advance our understanding of the natural world. Despite remarkable progress (Gunning et al., 2010; Berant et al., 2014; Cohen, 2015a), current machine reading systems face two major obstacles which impede wider adoption: <i>Assembly</i> The majority of machine reading systems extract disconnected findings from the literature (Berant et al., 2014). In areas of study such as biology, which involve large mechanistic systems with many interdependent components, it is essential that the insights scattered across the literature be contextualized and carefully integrated. The single greatest challenge facing machine reading is in learning to piece together this intricate puzzle to form coherent models and mitigate information overload. In this work, I will demonstrate how disparate biomolecular statements mined from text can be causally ordered into chains of reactions (Hahn-Powell et al., 2016b) that extend our understanding of mechanistic biology. Then, moving beyond a single domain, we will see how machine-read fragments (influence relations) drawn from a multitude of disciplines can be assembled into models of children’s heath. <i>Hypothesis generation and “undiscovered public knowledge”</i> (Swanson, 1986a) Without a notion of research communities and their interaction, machine reading systems struggle to identify knowledge gaps and key ideas capable of bridging disciplines and fostering the kind of collaboration that accelerates scientific progress. With this aim in mind, I introduce a procedure for detecting research communities using a large citation network and derive semantic representations that encode a measure of the flow of information between these groups. Finally, I leverage these representations to uncover influence relation pathways which connect otherwise isolated communities.
  • Supporting Parents as College Advisors: A Qualitative Study of First Generation College Students' Parents

    Valencia, Marylyn (The University of Arizona., 2018)
    This study identified first-generation college student’s parents’ needs and support systems during their child’s college admissions process. Literature supports the benefits of improving college knowledge among high school parents of first-generation college students. Parent college knowledge includes information about the college admissions requirements, college admissions processes, parental involvement, and access to social support. Research on these populations is more commonly done through quantitative studies that do not always include parents’ voice or qualitative research that tends to highlight students’ experiences. Regardless of the type of research, parents’ ability to provide guidance has a significant impact on first-generation college students’ enrollment and retention rates (Auerbach, 2007; Duggan, 2001). Social capital informed the design of this study to examine the access of college knowledge resources used by first-generation college students’ parents. The qualitative study was supported in a constructivist epistemology. Data were collected through semi-structured focus groups and individual interviews, which included 28 high school parents and/or guardians. Results categorized into three factors: college admissions requirements, the navigation of the college admissions process, and access to social support for guidance. The study concludes with findings that allow educators to better understand the needs of first-generation college students’ parents as well as steps that can be taken to provide parents with the tools needed to better guide their children through the college admissions process. Keywords: parent college knowledge, educational equity, college admission, high school
  • The Nature of the Vertical Distribution of Seismic Responses in Multi-Story Structures

    Kuzucu, Ismail Bahadir (The University of Arizona., 2018)
    This Ph.D. research investigates the vertical distribution of seismic responses and controlling seismic response patterns in multi-story reinforced concrete and steel structures. Seismic responses of buildings designed by conventional force-based or displacement-based approaches result in significant force demands compared to nominal design as observed in both experimental studies and earthquake simulations. Furthermore, force patterns suggest that the floor forces are predominantly controlled by higher modes especially when modal properties of buildings alter due to inelastic deformations. Therefore, actual force patterns experienced by buildings may not comply with the design code assumptions such as equivalent lateral force or response spectrum analysis. The main assumption in those methods, that the response of a building is dominated by the first mode excitation, may not be valid under strong earthquakes when inelastic deformations contribute significantly to the total response. Design code assumptions imply inelasticity to have same effects in all modes of response, though it may have significant effects on the demands associated with the first mode, higher modes may not be affected the same way. Further the distribution of seismic responses may differ for different types of lateral force resisting systems since each system possesses different response mechanisms such as formation of inelastic deformations. To better understand the distribution of seismic demands, response intensity measures obtained through nonlinear time history analysis are examined closely in terms of magnitude and shape along the height of buildings for different types of lateral force resisting systems in this study. This dissertation examines various types of buildings to address and shade light on those issues and observations mentioned above.
  • Passive Strategies to Improve Energy Efficiency in Existing and Pursuing Leed® Certified Buildings in Arid Regions

    Simmerman, Cecilia (The University of Arizona., 2018)
    Energy efficiency in buildings is vital for the environment and sustainability. Edifices are responsible for significant energy consumption and carbon dioxide emissions. “LEED® provides a framework to create healthy, highly efficient and cost-saving green buildings” (10). This framework that LEED® developed and the variety of paths to achieve points for certification make it very easy to bypass the energy category and produce underachieving buildings regarding energy efficiency. I think to create sustainable structures it is essential to employ passive strategies, and this study will illustrate that some LEED® Certify Building rely more on active systems rather than passive systems. This research will also demonstrate through energy simulation that passive strategies minimized external loads due to climate and are very effective in a hot arid climate. These strategies are sustainable reduce energy consumption are cost effective and without risk of mechanical or user failure. Because of investigation, a check list was developed to aid designers create more efficient structure using passive strategies.
  • Planetary Granular Topography: Slope Angles & Crater Concentric Ridges

    Atwood-Stone, Corwin (The University of Arizona., 2018)
    In the first portion of this dissertation I examine the effect of gravitational acceleration on the angle of repose of granular features. To do this I have used HiRISE DTMs to compare the slipface angles of Martian sand dunes with those measured on Earth. In doing this I have found that the slopes of active dunes on Mars do not differ from their terrestrial counterparts, and as such I have concluded that gravitational acceleration does not effect the angle of repose. In the second, larger portion of this dissertation I examine the morphology and formation of Crater Concentric Ridges (CCRs). These features, formerly known as 'Lunar Concentric Dunes', are ridges oriented concentrically to fresh craters a few kilometers in diameter. Using LROC NAC data I have created a catalog of 77 craters that have these features in their ejecta blankets. Further, I have used this data to map and measure the CCRs around eight craters of varying diameters in order to analyze their distributions. I have also been able to characterize the morphology of these ridges and how that morphology changes with distance from the host crater. Using DTMs made from NAC images I have studied the three-dimensional topography of CCRs in order to fully describe the morphology of these features. This morphological analysis has allowed me to refute several hypotheses for the formation of these features, including the previously accepted ballistic impact sedimentation and erosion hypothesis. In order to formulate a new theory for the formation of these features I have created simulations of crater ejecta flowing over regolith using discrete element modeling. In these simulations I found that Kelvin-Helmholtz instabilities form at the interface between the ejecta and regolith. I posit that these instabilities are responsible for the formation of Crater Concentric Ridges. This hypothesis is supported by the observation that the topography produced in my simulations strongly resembles that which I have measured and described around real lunar craters.
  • Experimental and Flight Investigation of the Laminar Separation Bubble on an Oscillating X-56A Wing Section Near Stall

    Agate, Mark (The University of Arizona., 2018)
    An investigation of laminar separation bubble behavior on an oscillating X-56A wing section has been performed experimentally at Reynolds number 200,000. Wind tunnel results along with Implicit Large Eddy Simulations (CFD) quantify the behavior of the laminar separation bubble. The oscillation parameters were selected based on a scaled flight vehicle at the University of Arizona. Wind tunnel results were validated against theory using static angle of attack sweeps and an unsteady case at an angle of attack of $\alpha = 10$ degrees. The static results show excellent agreement between the experimental data, Thin Airfoil Theory, a computational vortex lattice method (XFLR5), and CFD results in both pressure coefficient and lift coefficient. The unsteady validation case of $\alpha=10$ degrees (nondimensional plunging frequency of $k = \frac{\pi f c}{U_{\infty}}=0.7$, where $f$ is the dimensional plunging frequency, $c$ is the wing section chord, and $U_{\infty}$ is the free-stream velocity, and nondimensional plunging amplitude $h = \frac{amplitude}{chord} = 3.2\%$) also showed agreement for comparison between the experiment, Theodorsen's theory (analytical solution to plunging wing sections), and CFD results. Pressure coefficient behaved similarly between the experiment and CFD with the laminar separation bubble changing pressures at similar times in the cycle. The lift coefficient was found to oscillate sinusoidally, achieving higher lift than the static case with no moment stall. Near static stall angle of attack ($\alpha=12$ degrees, where stall $\alpha=12.25$ degrees), Theodorsen's theory is no longer applicable. Oscillation parameters were $k=0.7$ and $h=4.8\%$ and effective angles of attack reached nearly $16$ degrees. The airfoil continued to produce lift past static stall at the consequence of a moment stall. Pressure measurements indicate that the laminar separation bubble is shed from the leading edge which was confirmed through 2D particle image velocimetry. The shedding behavior was modeled differently in the CFD simulation with a lack of free-stream turbulence. However, pressure coefficient and lift coefficient are in excellent agreement for over $75\%$ of the oscillation cycle. It is shown that the experimental setup is valid and the increased aerodynamic efficiency comes at the consequence of a moment stall for the high angle of attack case ($\alpha=12$ degrees). Additionally, free-flight tests have been completed including maiden flights of the 1/3 scale X-56A vehicle built at The University of Arizona. The flight vehicle is the motivation for the wind tunnel parameters. Flight instruments have been verified against previously collected data including pressure sensors, wing accelerometers (to track the motion), and a stand-alone constant temperature anemometry (CTA) system to measure free-stream turbulence. The instrumentation was flown on a stable platform to compare to historical data (1/5 scale Ximango) and is performing nearly 10 times as fast (data collection frequency) of the expected phenomenon occurring with the laminar separation bubble shedding on the 1/3 X-56A vehicle. This will need to be analyzed in future work as the laminar separation bubble is sensitive to free-stream turbulence conditions.
  • Differential Impacts of Passive versus Active Irrigation on Semiarid Urban Forests

    Luketich, Anthony (The University of Arizona., 2018)
    Trees provide benefits to the urban environment and irrigation is common to support these ecosystem services. In dryland communities where water resources are limited, collection and retention of stormwater runoff is used to passively irrigate the urban forest. However, the effects of passive irrigation versus regular, controlled moisture inputs, or active irrigation, is largely unquantified. We monitored the ecohydrology of urban mesquite trees (Prosopis spp) under these contrasting irrigation regimes in semiarid Tucson, AZ. Measurements included soil moisture, sap flow, canopy greenness, and leaf-area index. We expected both irrigation types to provide additional deep (>20 cm) soil moisture compared to natural conditions, and that trees would depend on this deep soil moisture for transpiration and phenological activity. Results show that active irrigation supported higher soil moisture, sap flow, and greenness during the dry conditions of spring. Following summer rain, greenness was higher under passive irrigation, despite sustained elevated soil moisture under active irrigation. Deep soil moisture had only slightly stronger controls over mesquite productivity than shallow moisture, and these relationships were stronger in the spring, rather than summer months. Finally, passive irrigation generally failed to provide additional deep soil moisture, though treatments in closer proximity to impervious surfaces did provide wetter soil conditions. This research aims to contribute empirical observations of green infrastructure performance and improved understanding of urban forest function for watershed management and planning.
  • Rationality and Resentment in the Egyptian Critique of Orientalism: The Example of Anouar Abdel-Malek and Ḥasan Ḥanafī

    Allosh, Islam (The University of Arizona., 2018)
    Fifteen years before Edward Said published his seminal book Orientalism, Anouar Abdel-Malek (1924-2012), an Egyptian alumnus of the Sorbonne and a Sociologist in the French National Center for Scientific Research (CNRS), had published his contentious article entitled “Orientalism in Crisis” in 1963. The essay placed Abdel-Malek as the first Arab thinker to critique Orientalism in a European language. In 1991, Ḥasan Ḥanafī (b. 1935), an Egyptian philosopher and Sorbonne graduate, published Introduction to the Science of Occidentalism. He presents the book as the first serious formation of an Eastern science capable of challenging Eurocentrism and countering Western Orientalism. The present study implements Partha Chatterjee’s (b. 1947) model of the three moments in the development of the Nationalist thought in India on Anouar Abdel-Malek and Ḥasan Ḥanafī in the context of restructuring the power relations between the East and the West. Chatterjee argued that nationalist thought in the colonial world, while seeking to liberate itself from the imperialist influence, remained a prisoner of the post-Enlightenment Western thought. It will be argued that Ḥasan Ḥanafī, who fits in the third moment, the moment of arrival, could not escape the Orientalist mode of knowledge. It will also be argued that Anouar Abdel-Malek, who fits in the third moment as well, has successfully managed to overcome the nationalist dilemma suggested by Chatterjee. The moment of arrival represents a fully developed ideology that embraces the different components of a nation.
  • Mean Flow Structure of Swept Impinging Oblique Shock Boundary Layer Interactions

    Doehrmann, Adam (The University of Arizona., 2018)
    An experimental investigation has been conducted to assess the e↵ect of sweep on the mean flow structure of impinging oblique Shock/Boundary Layer Interactions (SBLIs), specifically focused surface flow visualization and mean wall pressures. Four shock generators are utilized with x-y plane deflection of ✓ = 12.5!, and x-z plane sweep angles of 15.0!, 22.5!, 30.0!, and 40.0!. The swept oblique shocks impinge upon the naturally turbulent Mach 2.3 boundary layer along the tunnel floor (Re✓ ⇡ 5000). The resultant SBLIs all exhibit significant separation, with a structure that grows in the spanwise direction. Surface flow visualization shows a quasi-infinite region of separation that is limited by corner e↵ects at the root and tip of the interaction. The rise in mean pressure near separation scales locally with cylindrical similarity suggesting the three-dimensional separation along the span obeys Free Interaction Concept. Local reattachment behavior is only mildly dependent upon span. Convention from literature states that when the flow features, such as separation and reattachment lines are parallel, the interaction scales cylindricalyly. Conversely, when these flow features diverge from each other, the interaction scales conically. Divergence of separation and reattachment lines indicated that the global shock structure scales cylindrically for shock generator sweep angles less than 22.5! and conically above this angle. Another wind tunnel configuration suggests that the incoming boundary layer can influence this behavior. Similar trends to compression ramp observations (Settles and Teng, 1984) are seen for the asymptotic behavior of the inception length near the root of the SBLI. This suggests a cylindrical/conical boundary similar to that found from the divergence of separation and reattachment lines. The root behavior was further investigated using a delta shock generator producing an inviscid shock similar to the shock generator with an x-z plane sweep angle of 22.5!. Surface flow visualization shows good agreement between the two shock generators at the separation line. The pressure at separation also appears to align between the two, but the delta span, which is limited by tunnel size, is not sufficient to generate a quasi-infinite region.
  • Lossless Image Compression using Reversible Integer Wavelet Transforms and Convolutional Neural Networks

    Ahanonu, Eze (The University of Arizona., 2018)
    Image compression is an area of data compression which looks to exploit various redundancies that exist within images to reduce storage and transmission requirements. In information critical applications such as professional photography, medical diagnostics, and remote sensing, lossless image compression may be used to ensure the original data can be restored at a later time. In this work, a lossless compression framework is proposed which incorporates Convolutional Neural Networks (CNNs) to predict wavelet detail coefficients from coefficients within neighboring subbands. The main premise of the proposed framework is that information which can be recovered at the decoder via CNN prediction can be excluded from the compressed codestream, resulting in reduced file sizes. An end-to-end encoder and decoder is implemented to test the validity of the proposed, model and compression performance is compared with current state of the art methods.
  • Gender Differences in Achievement Emotions: A Control-Value Theory Approach

    Di, Shuxin (The University of Arizona., 2018)
    The current study examines whether there are gender differences in general academic contexts within three achievement emotions: prospective outcome emotions, retrospective outcome emotions and activity emotions. I combined Pekrun’s control-value theory with the Achievement Emotion Questionnaire (AEQ) to assess participants’ achievement emotions. Discriminant function analysis revealed statistically and practically significant gender differences in prospective outcome emotions and activity emotions, but not in retrospective outcome emotions. Moreover, females scored higher on three achievement emotions: prospective outcome emotions, retrospective outcome emotions, and activity emotions than males in this study. The current study filled in the gap of prior studies which have not explored gender differences in three achievement emotions: prospective outcome emotions, retrospective outcome emotion and activity emotions, in general domains. Future studies could replicate the current study and explore if other factors would influence the impact of gender on achievement emotions, for example, culture and age. Additionally, researchers could try to apply achievement emotions to improve students’ academic performance.
  • Spinning Records: How Hip-Hop is Used in the Tucson Community

    Barbre, Joshua (The University of Arizona., 2018)
    The phenomenon of hip-hop began as a local musical practice in New York in the 1970s and from that local practice developed into a formally recognized musical genre, and furthermore, into a viable and distinct culture – a way of life – in its own right. Hip-hop has expanded its formerly narrowly-defined demographics and indoctrinated a broad cultural diversity of contributing artists to become a truly global musical and cultural phenomenon. Hip-hop culture is signaled, enacted, and expressed fundamentally through rapping, deejaying, graffiti, and dance. It was designed to accommodate and support dual identities for its practitioners, through both an acquired identity of affiliation within hip-hop and an identity of affiliation within the locale in which they develop and operate. The members of the Tucson, AZ hip-hop community, the subjects of this study, claim that what defines Tucson’s hip-hop is not how it sounds, but how it is used within the local hip-hop community as well as within the greater Tucson community. This study examines the relationships, symmetrical and asymmetrical, that exist between hip-hop and Tucson. Furthermore, I demonstrate how hip-hop deejays in Tucson serve a pivotal role in connecting the local hip-hop community to the greater Tucson community. Their idea of a hip-hop identity is fluid; therefore, through adaptable performance practice, they can achieve different aims at different times to satisfy different target audiences. Ultimately, what is most vital to their success, and by extension that of the hip-hop community in Tucson, in general, are their multipronged efforts to establish and maintain a strong sense of community through education, collaboration, and support of their fellow artists.
  • Determination of Stress in Humans Using Data Fusion of Off-The-Shelf Wearable Sensors Data for Electrocardiogram and Galvanic Skin Response

    Jeroh, Odafe (The University of Arizona., 2018)
    Stress detection helps individuals understand their stress levels and advises them when to take a break from activities causing stress. Physical activities and environmental influences can affect a person’s stress levels. People with professions as first responders, pilots, and working parents with newborns are examples of people exposed to a large amount of stress. Acquisition and proper analysis of physiological data is helpful in managing stress. In this paper, the results from two sensors, electrocardiogram (ECG) and galvanic skin response (GSR) measurements, are fused to analyze stress in individuals; these sensors are noninvasive and wearable. Data from these sensors are collected simultaneously over a period of 25 minutes from 25 people which are undergoing a simulated stressor. Support Vector Machine (SVM) and Multilayer Perceptron (MLP) are used as the classifiers while Linear Discriminant Analysis (LDA) is used as the stress detection algorithm. The stress detection accuracy achieved varies with individuals and ranges from 87% to 95%. This approach of measuring stress is very suitable for real-time applications and can be used by practically anybody who wants to improve their performance.
  • Socially Constructed Narratives for Exploring the Impacts of Air Pollutant Infiltration in Built Environments

    Bernal, Sandra Maria (The University of Arizona., 2018)
    This dissertation is an autoethnographic (self-guided) interdisciplinary process done by an empathetic entity (me) who noted a problem sorting out the effects of outdoor air pollutants that infiltrate indoors from those of other indoor pollutants. This problem is the lack of understanding by architects, planners, and other experts of relevant implications of their lack of attention to the infiltration of airborne dust indoors in the arid regions of Arizona. This systematic process of informed reflections is written in a continuous narrative, and breakouts or Vignettes. Each Vignette corresponds to a topic directly relevant to the research and contains the evidence that answers an inquiry followed by a reflection based on my experience and observations. In the study of arid lands, autoethnographic Vignettes provide an alternative approach for taking a scientific point of view to reveal complex interactions between the natural and built environments for arid regions and other regions that may experience drier and warmer climatic conditions in the future.
  • Statistical Methods for Next Generation Sequencing Data

    Zhang, Miao (The University of Arizona., 2018)
    Statistical genetics is a scientific field concerned with the development of statistical methods for drawing inferences from genetic data. Research in statistical genetics generally involves developing theory or methodology to support research in one of three related areas: population genetics, genetic epidemiology and quantitative genetics. This dissertation is an ensemble of my research work in statistical genetics, including three projects with varying focuses. The first project applies a rare variant region-based test to identify sets of common or rare variants aggregated in and around genes associated with Dravet Syndrome. The second project proposes a score-based test to investigate the association for a set of rare variants and ordinal traits. The third project describes an implement of dimensionality reduction method in genotype data for population inference.

View more