Now showing items 21-40 of 36697

    • Disability as an Identity: Disability Cultural Centers in Higher Education

      Hartley, Michael T.; Saia, Toni Ann; Kraus, Amanda; Johnson, Philip; Tashjian, Amanda; Mapes, Aimee (The University of Arizona., 2019)
      Focused on the role of a disability cultural center in higher education from the perspective of disabled students, this qualitative study used a social constructivism lens to examine how disability is conceptualized through a medical versus social model on a college campus. Framing disability as an identity and social justice issue, the intent of this study was to explore the disability experience as well as the role that a disability cultural center could play in addressing social inequities faced by disabled students. Importantly, this study was one of the first to focus on how a disability cultural center can create a more welcoming campus climate for disabled students within higher education. Based on the perspectives of six disabled students, the themes that emerged from the qualitative interviews highlighted a clear distinction between how participants believed the institution viewed the disability experience compared to the disability cultural center. Recognizing disability as a form of diversity, generative insights from the interviews revealed broad benefits of a disability cultural center beyond the accessibility role of a disability resource center. In particular, a disability cultural center is an avenue to: (a) increase disability leadership on campus, (b) promote more welcoming attitudes toward disability, (c) improved faculty training regarding the disability experience, (d) cultivate pride in disability culture, and (e) embrace disability as a valid human identity. Moving forward, the results of the present study may inform the development of new disability cultural centers across the United States to challenge ableism, including non-disability privilege and oppression. With this in mind, implications for institutions are presented to inform higher education and shift the narrative of disability from a medical diagnosis to a valid social identity on campus.
    • Visual Integration and the Role of Structural and Functional Brain Changes in the Age-Related Associative Memory Deficit

      Ryan, Lee; Memel, Molly; Glisky, Elizabeth; Alexander, Gene; Grilli, Matthew (The University of Arizona., 2019)
      In the present set of experiments, we investigated the effects of visual integration, and age-related changes in brain structure and function on associative memory for objects and scenes. The results of experiment 1 demonstrated improved associative memory when objects and scenes were visually integrated, through an increase in hits without a corresponding increase in false alarms. This profile was interpreted to reflect an increase in recollection-based responding when associative pairs were visually integrated. Although processing of visually integrated stimuli resulted in greater activation across medial temporal lobe (MTL) structures (e.g. hippocampus (HC), perirhinal cortex (PRC), parahippocampal cortex (PHC)) compared to non-integrated pairs and their respective controls, no difference in MTL or prefrontal (PFC) activation was observed after accounting for control activation. In young adults, activation across all three MTL structures predicted discrimination for non-integrated pairs, but only PRC activation predicted discrimination for visually integrated pairs. In older adults, MTL activation was not related to performance for non-integrated pairs, but HC and VLPFC activation predicted performance for visually integrated pairs. In experiment 2, we investigated differences in reaction time based on visual integration, and the neural correlates of associative recognition. Both young and older adults responded faster to visually integrated than non-integrated pairs, reflecting increased recollection-based responding. However, the difference between conditions was greater in older adults. While both groups exhibited a reduction in right HC and left PRC activation during recognition of visually integrated compared to non-integrated pairs, an interaction occurred in left medial HC. Young adults exhibited reduced activation in this region for visually integrated pairs, whereas high functioning older adults activated this region more for visually integrated than non-integrated pairs. Similar to results from encoding (Experiment 1), HC activation was associated with recognition of non-integrated pairs in young adults, but no MTL region predicted performance for visually integrated pairs. In contrast, HC and PHC activation was only related to memory for visually integrated pairs in older adults. Contrary to findings from the verbal unitization literature that demonstrate improved memory in older adults through increased familiarity-based responding (Zheng et al., 2015; Ahmad et al., 2015), our findings suggest that visual integration improves performance across age-groups through an increased reliance on recollection. Notably, the neural correlates of this shift vary based on age. Finally, in experiment 3, we examined the role of white matter integrity in the tracts connecting frontal and temporal brain regions in predicting associative memory. White matter integrity in the fornix, uncinate fasciulucs, and PHC cingulum predicted associative memory in older adults, even after controlling for global white matter changes. The present findings demonstrate the benefit of visual integration as a strategy to improve associative memory across age groups. Further, we identified age-related changes in brain function and structure that are related to memory for visual pairs of objects and scenes.
    • Alterations in Stress Physiology Following Yogic Breathing and Cognitively Based Psychosocial Workshops for College Students

      Allen, John JB; Goldstein, Michael R.; O'Connor, Mary-Frances; Ruiz, John; Bailey, Elizabeth F. (The University of Arizona., 2019)
      College and graduate school present a number of challenges for students, often while they are also juggling other major life transitions that impact social relationships, sleep, physical health, and overall well-being. In this study, students were randomized to one of two psychosocial stress-management interventions. One workshop, Your Enlightened Side (YESplus), taught a yogic breathing and acceptance-based approach to stress-management in a rich social environment. Wisdom On Wellness (WOW), in contrast, targeted cognitive approaches to stress-management while matching YESplus in terms of scheduling and duration (4 consecutive days, 18 hours total), group size, amount of material, general format, and involving some level of social interaction. Outcomes were evaluated across self-report domains of stress and wellness, as well as psychophysiological response to a laboratory stress induction at pre, post, and 3-month follow-up. Forty-five students completed all timepoints and were used for analysis. YESplus and WOW participants reported similarly high ratings of the workshops, along with similar retention rates from first to last day of workshop (92% vs. 91%), as well as from post to 3-month follow-up (79% vs. 70%). YESplus demonstrated significant decreases in perceived stress at post (-24.6% average change, p=.017, d=-0.58) as well as 3-month follow-up (-22.3%, p=.002, d=-0.84) relative to pre-workshop, in contrast to no significant changes for WOW (0.8% average change at post and -10.5% at follow-up). A number of other improvements in self-report measures of well-being including sleep, social connectedness, depression, self-esteem, and life satisfaction were observed for YESplus, but not WOW, after correcting for multiple comparisons. At laboratory visits, WOW demonstrated anticipatory stress-related increases in resting breathing rate and heart rate from pre to post-workshop, while YESplus demonstrated a protective effect and did not change. Decreases in heart rate during stress induction were evident for both groups at post-workshop as well as 3-month follow-up relative to pre-workshop (d’s=-0.52 to -0.92). However, improvements in heart rate variability were significant after correction for multiple comparisons only for WOW. These findings have implications for understanding changes in subjective well-being and acute stress physiology in response to brief psychosocial and breathing-based versus cognitively based interventions.
    • A Randomized Controlled Pilot Trial of a Mindfulness Intervention for Grief in Widows and Widowers

      O'Connor, Mary-Frances; Knowles, Lindsey M.; Sbarra, David A.; Lawrence, Erika E.; Kaszniak, Alfred W. (The University of Arizona., 2019)
      Background: Following bereavement, prolonged and intense yearning and grief rumination are repetitive cognitive processes that can promote a complicated course of grief. Mindfulness training (MT) has been shown to reduce maladaptive repetitive thought in healthy and clinical populations. However, empirical investigation of MT in bereaved populations is limited. The current randomized controlled pilot trial implemented a MT intervention for widow(er)s to examine the feasibility, acceptability, and preliminary efficacy of MT for improving grief outcomes and to test the mediating effects of yearning and grief rumination on grief severity. Method: Ninety five people who experienced the death of a spouse or romantic partner between six months to four years prior were randomly assigned to a 6 week MT intervention or a Progressive Muscle Relaxation (PMR) intervention, or were quasi randomized to a wait list condition. Self reported psychosocial outcomes were assessed at baseline, post intervention, and 1 month post intervention. In addition, yearning, grief rumination, decentering, and grief severity were assessed at two additional time points at weeks two and four of the intervention/wait list period to preserve a temporal connection between mediators and outcomes. Results: Controlling for relevant covariates, the MT and PMR groups showed significant declines in grief severity and yearning from baseline to the 1 month follow up, though only the PMR group showed a significant difference in rates of change compared to the wait list control group. Multi level mediation analyses revealed that reductions in yearning mediated the declines in grief severity. The MT, PMR, and wait list groups showed significant decreases in grief rumination across intervention time points for all but one grief rumination subscale, which was rumination about injustice of the death. Last, the PMR and wait list groups showed significant increases in decentering across study time points whereas the MT group did not experience significant change. Conclusion: The results of this first pilot RCT of a MT intervention in widows and widowers support the feasibility, acceptability, and preliminary efficacy of MT and PMR for improving grief outcomes in widows and widowers, and they suggest that PMR is most effective compared to the wait list control. With replication, PMR and MT could be standalone interventions for normative grief or components added to treatments for disordered grief.
    • Land Disturbance Influences Seed-Microbe Associations in a Semi-Arid Ecosystem: Microbial Recruitment and Student Engagement

      Arnold, A Elizabeth; Leo, Ashton Bruce; Hu, Jiahuai; Schuch, Ursula (The University of Arizona., 2019)
      All terrestrial plants in natural and altered ecosystems form symbiotic relationships with microbes. The outcomes of these relationships can be detrimental or beneficial, depending on the confluence of plant genotypes, microbial genotypes, and environmental factors. This thesis focuses on the identification of beneficial microbes that infect seeds in the context of natural and altered environments, and describes how that topic can be used as a platform for a STEM-focused outreach experience for high school students. I first examined the abundance, diversity, and composition of soilborne fungi that infect seeds of a restoration plant, focusing on gradients of land degradation at the Santa Rita Experimental Range (SRER) of southeastern Arizona. I tested the predictions that (1) beneficial microbes would differ as a function of land disturbance, and (2) such effects of disturbance would be mitigated by plant cover. I identified a set of potentially beneficial microbes that may be used in revegetation strategies in disturbed soils. I then translated this experimental approach to form the centerpoint of a multidisciplinary outreach program, which I developed and implemented as an immersive summer program that combines scientific investigation with outreach to underrepresented youth in STEM. Thus this thesis addresses both a scientific question of applied significance as well as a societal need for training and diversification in STEM.
    • Characterizing the Atmospheres of Exoplanet Populations: From Sub-Jovian to Ultra-hot Jupiter Exoplanets

      Barman, Travis; Lothringer, Joshua David; Crossfield, Ian; Koskinen, Tommi; Yelle, Roger; Youdin, Andrew (The University of Arizona., 2019)
      With thousands of exoplanets now discovered and the diversity of worlds beyond our solar system being unveiled, we are now beginning to understand exoplanet populations in detail. The most direct way that we can characterize an exoplanet is by studying its atmosphere. This dissertation uses both observations and modeling to explore the properties of different exoplanet populations. Using transit spectroscopy with HST/STIS, I observed the atmosphere of the JWST GTO target GJ 436b. The resulting optical spectrum is consistent with a cloudy, moderate metallicity atmosphere. I find intriguing similarities in the optical transit spectrum of several sub-Jovian exoplanets and explore possible explanations. While sub-Jovian exoplanets are on the frontier of characterization, ultra-hot Jupiters are some of the most ideal targets for observation due to their high temperature, inflated radii, and short periods. Using the self-consistent PHOENIX atmosphere model, I show that the atmospheres of ultra-hot Jupiters exhibit some unique properties, including thermal dissociation and intense temperature inversions, even in the absence of TiO or VO. I also show that my models qualitatively match the characteristics seen in many ultra-hot Jupiter observations. Since ultra-hot Jupiters are amongst the most highly irradiated objects, I explore the role that the host star irradiation spectrum plays in the planet’s temperature structure and composition, finding that ultra-hot Jupiters around hotter host stars will have more intense thermal inversions. I also further quantify the opacity sources responsible for heating ultra-hot Jupiter atmospheres. Lastly, I present some novel techniques to characterize exoplanet atmospheres using PETRA, a new retrieval framework I have built around PHOENIX.
    • Flavor Physics with Heavy Baryons and Resonances Using Lattice QCD

      Meinel, Stefan; Rendon Suzuki, Jesus Gumaro; Johns, Ken; Su, Shufang; Toussaint, Doug; Varnes, Erich (The University of Arizona., 2019)
      Flavor-changing transitions play an important role in the search for new physics beyond the Standard Model (SM). In order to compare experimental results with SM theoretical predictions we must calculate hadronic matrix elements in Quantum Chromodynamics (QCD). In order to perform such calculations we use formulations of QCD on a Euclidean space-time mesh. Having a discretized Euclidean QCD action allows us to use Monte Carlo methods to generate the field configurations we use to evaluate the path integral numerically. In this thesis, we present results on the lattice calculation of matrix elements for decay processes with negative parity baryons in the final state, Λb → Λ(1520)ℓ+ℓ- , Λb → Λc (2595)ℓ-ν, and Λb → Λc(2625)ℓ-ν , which are under investigation by LHCb and can provide new information on current tensions seen in mesonic b → sμ+μ- and b → cτ-ν transitions. We also present preliminary results on form factor calculations for the process Λc → Λ(1520)ℓ+ν which can be measured by the BESIII and Belle II experiments. One of the most important contributors to the tensions in mesonic b → sμ+μ- transitions is B → K*(892)μ+μ- . The theoretical calculations used for B →K*(892)μ+μ- were performed assuming the K*(892) is a stable hadron; however, in reality this state is unstable under the strong force. In order to do a proper treatment, one has to calculate the B → Kπ matrix elements and the finite volume effects of the lattice have to be accounted for using the Briceño-Hansen-Walker-Loud (BHWL) formalism. For that, we will need to first calculate the Kπ scattering amplitudes from multi-hadron spectra on the lattice. We have done these calculations and present results here. Another similar process of interest is B → ρ(→ ππ)ℓ-ν, which would help understand better the tensions between exclusive and inclusive determinations of |Vub |. For that reason, we also present results on the necessary ππ (JPC = 1−− , I = 1, I3 = 1) scattering amplitude obtained from the lattice. The task of extracting the B → ρ(→ ππ)ℓ-ν and B → K*(892)(→ Kπ)μ+μ- transition matrix elements from the three-point functions is still in progress. However, we have completed this step for a simpler 1 → 2 process, πγ → ρ(→ ππ), that will help us pave the way for the proper treatment of B → ρ(→ ππ)ℓ-ν and B → K*(892)(→ Kπ)μ+μ- using BHWL.
    • Observational and Theoretical Cosmology with Novel Statistical Methods

      Melia, Fulvio; Leaf, Kyle Kevan; Sandhu, Arvinder; Su, Shufang; Rafelski, Johann; Fleming, Sean (The University of Arizona., 2019)
      The standard ΛCDM model of the universe has been shown to be consistent with a wide range of astronomical observations, including many properties of the cosmic microwave background (CMB). However, the model has significant tension with an increasing set of measurements, ranging from determinations of the Hubble Constant to the angular correlation function of the CMB. This motivates revisions to ΛCDM, or the consideration of alternative models (or even entirely new physics). The Rh=ct universe is an alternative FLRW cosmology that has thus far performed very well in describing a wide range of astronomical observations. In this dissertation, I present a sequence of tests of cosmology. These tests are designed to determine whether the Rh=ct universe performs better than the standard model in accounting for the considered data. First, I show the development of a two-point diagnostic to compare a model’s predictions with observations. This diagnostic is applied to passively evolving elliptical galaxies (cosmic chronometers) and the Hubble diagram as constructed using HII galaxies. Second, I make use of relative likelihoods with strongly-lensed galaxies to constrain standard ΛCDM and an alternative dark matter parameterization (wCDM). These model fits are then compared with the Rh=ct universe by means of several information criteria. Each of the direct comparisons using existing data favor the Rh=ct universe over standard ΛCDM to different degrees, warranting further research to determine whether it accurately describes the Universe. Finally, I present a theoretical prediction of the number of z>6 blazars that will be detectable by upcoming surveys by the Square Kilometer Array (SKA). This prediction is entirely phenomenological, based on spectral energy distribution (SED) measurements of known blazars. The predictions for the number of blazars detectable by SKA between these models are incompatible, such that either the Rh=ct universe or ΛCDM will be strongly preferred by the surveys.
    • Analog Optical Computing Using Nonlinear Optics and Photonics

      Peyghambarian, Nasser; Babaeian, Masoud; Norwood, Robert A.; Visscher, Koen; Manne, Srinivas; Wang, Weigang (The University of Arizona., 2019)
      Analog optical computing uses nonlinear optics and photonics to bring new approaches to attacking several important computational problems that current electronic computational platforms struggle to perform efficiently in terms of energy consumption and time. In this dissertation, Chapter 2, I will demonstrate optical implementation of Probabilistic Graphical Models (PGMs) which are tools that are used to compute probability distributions over large and complex interacting variables. They have applications in social networks, speech recognition, artificial intelligence, machine learning, and many more areas. Our analysis indicates that the optical implementation provides substantial reduction of power and area compared to the electronic-based solutions as problems become large. For a network with 1 million nodes and 100 alphabet size, our proposed wavelength multiplexed all-optical implementation requires approximately 200 kilowatts (kW) of power as compared with 1.47 gigawatts (GW) and 1.7 megawatts (MW) using CPU-based and subthreshold VLSI-based systems, respectively. The optical-based solution is tolerant to shot noise and imperfections of optical modules used in the architecture as well. We also present an all-optical implementation of a PGM through the sum-product message passing algorithm (SPMPA) governed by a wavelength multiplexing architecture. As a proof-of-concept, we demonstrate the use of optics to solve a two node graphical model governed by SPMPA and successfully map the message passing algorithm onto photonics operations. The essential mathematical functions required for this algorithm, including multiplication and division, are implemented using nonlinear optics in thin film materials as well as bulk materials. The multiplication and division are demonstrated through a logarithm-summation-exponentiation operation and a pump-probe saturation process respective. The fundamental bottlenecks for the scalability of the presented scheme are discussed as well. In Chapter 3, I will present a coherent Ising machine (CIM) and discuss its importance for solving combinatorial problems. Combinatorial optimization problems over large and complex systems have many applications in social networks, image processing, artificial intelligence and a variety of other areas. Finding the optimized solution for such problems in general are usually in the non-deterministic polynomial time (NP)-hard complexity class. Some NP hard problems can be easily mapped to minimizing an Ising energy functional. I will demonstrate an analog all-optical implementation of a CIM based on a network of injection-locked multicore fiber (MCF) lasers. The Zeeman terms and the mutual couplings appearing in the Ising Hamiltonians are implemented using spatial light modulators (SLMs). As a proof-of-principle, we demonstrated the use of optics to solve several Ising Hamiltonians with size of N=3 (triangle topology), N=4 (square lattice), N=7 (1D chain) and N=13 example. We have obtained the exact ground state of the Ising Hamiltonians over several trials, while some of the trials converged on local minima. Overall, the average accuracy of the CIM for finding the ground state energy was ~ 90 % for 120 trials. Our results represent a curious effect in an analog non-linear optical system whose minimum energy state may encode interesting Ising-like computational problems. However, our results do not imply an analog solver for NP Hard problems. We identify several fundamental and experimental bottlenecks in the scalability, programmability, and most importantly the solution quality (approximation to the optimal solution) of the CIM we built, most of which also apply to various other proposals for analog Ising solvers discussed in the recent scientific literature. In the last chapter of the dissertation, Chapter 4, I will discuss linear and nonlinear optical behavior of a novel sulfur based polymer. These polymers are attractive for near-IR (NIR) and mid-IR applications. The two photon absorption (TPA) coefficient (β) and second order refractive index (n2) of Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs) from poly(sulfur-random-(1,3-diisopropenylbenzen) (poly(S-r-DIB)) are measured via the Z-scan technique. In this study, we have investigated the linear and nonlinear optical behavior of two types of CHIPs where the weight percent of sulfur is varied (poly(S50%-r-DIB50%) and poly(S70%-r-DIB30%)). The TPA coefficients for poly(S50%-r-DIB50%) and poly(S70%-r-DIB30%) are obtained to be 0.11 cm/GW and 0.063 cm/GW respectively. The n2 for poly(S50%-r-DIB50%) and poly(S70%-r-DIB30%) are measured to be 2.45×10-15 cm2/W and 3.06×10-15 cm2/W respectively and are in good agreement with Miller’s rule prediction. These materials exhibit low cost, low temperature processing, high transparency in the near to mid-IR range (except for few vibrational absorption peaks) and relatively high refractive index, providing a unique set of properties for optics and photonics device applications.
    • A Theory of Justice Pluralism

      Gaus, Gerald; Gjesdal, Adam; Christiano, Thomas; Schmidtz, David; Wall, Steven (The University of Arizona., 2019)
      Political liberalism aims to describe how a free, liberal political order can be justified in societies marked by deep, intractable disagreement about matters of religion, philosophy, and morality. My dissertation explores the implications for political liberalism of justice pluralism: the view that reasonable citizens can disagree over which theory of justice, of a set of eligible or “reasonable” theories, is best. I argue that the values of political liberalism that lead to acknowledging a pluralism of reasonable comprehensive doctrines also lead to seeing political liberalism as a two-level theory. There is the meta-level of political liberalism per se, and the level of specific conceptions of justice. Political liberalism per se respects reasonable disagreement about the design of an original position argument, seeing no single design as the most reasonable. Specific conceptions of justice like Rawls’ justice as fairness, in contrast, take a stand on which specific design of an original position argument is the most reasonable. As a result, at each level, political liberalism has different constraints on the claims it can make about the nature of a just society. The difficult challenge is to articulate in just what sense a reasonable citizen can embrace the meta-theory of political liberalism, which sees many reasonable conceptions as on par, while nevertheless, reasonably advocating their favored conception as the best. This dissertation attempts to meet this challenge, showing that while political liberalism per se does not take sides in disputes between reasonable conceptions of justice, it is open to citizens to embrace one conception that guides their reasoning about a range of political matters.
    • Identification of Poly(ADP-Ribose)-Associated Proteins and their Potential Role in ROS-Mediated Cell Death

      Zhang, Donna; Islas Robles, Argel; Monks, Terrence; Ooi, Aikseng; Wondrak, Georg; Boitano, Scott (The University of Arizona., 2019)
      2,3,5-Tris-(glutathion-S-yl)hydroquinone (TGHQ) is a nephrotoxic and nephrocarcinogenic metabolite of hydroquinone. TGHQ can redox cycle, generating reactive oxygen species (ROS) which cause DNA strand breaks, hyperactivation of poly(ADP-ribose) polymerase-1 (PARP-1), increases in intracellular calcium concentration ([Ca2+]i), ultimately resulting in cell death. PARP-1 is a nuclear protein involved in multiple cellular processes such as DNA repair, transcriptional regulation, and cellular differentiation. PARP-1 catalyzes the attachment of a post-translational modification, consisting of multi branched ADP-ribose polymers (PAR) on target proteins. In human renal proximal tubule cells (HK-2) ROS stress promotes PARP-1 hyperactivation and elevations in [Ca2+]i which are reciprocally coupled. The molecular mechanism of this interaction is unclear. The aim of the present study was to identify TGHQ-induced PAR-associated proteins and their potential role in cell death. HK-2 cell were treated with 400 μM TGHQ to induce ROS stress leading to PARP-1 hyperactivation. PAR-associated proteins were immunoprecipitated, followed by separation by SDS PAGE and proteomic analysis. A relative protein abundance analysis by spectral counts allowed us to obtain fold-changes in protein abundance relative to control. 356 PAR-associated proteins were significantly identified as modified by TGHQ treatment. From this cohort, 281 proteins showed an increased PAR association while 90 were decreased, and 169 appear to be novel interactors of PAR. Additionally, 13 targets had Gene Ontology annotations related to calcium. Of these, neuroblast differentiation-associated protein (AHNAK), calcium homeostasis endoplasmic reticulum protein (CHERP) and general transcription factor II-I (TFII-I) are directly involved in modulation of [Ca2+]i. TFII-I regulates [Ca2+]i by competing for phospholipase C (PLC) binding with the calcium channel TRPC3. Free PLC binds and promotes the translocation of TRPC3 to the plasma membrane leading to increases in [Ca2+]i. TGHQ induced TFII-I translocation from the nucleus to the cytosol, decreased tyrosine TFII-I phosphorylation, reduced PLC-TFII-I interaction, and increased PLC and TRPC3 translocation. However, pharmacological inhibition or depletion of TRPC3 or PLC did not have a protective effect in TGHQ-mediated decrease in cell viability, indicating that these proteins are not major players in TGHQ toxicity. Gene expression analysis reveals that the transcription of TFII-I-dependent genes is induced by TGHQ treatment, suggesting that PARylation of TFII-I regulates its transcriptional activity. Depletion of the TGHQ-induced differential PAR-associated proteins, PKM2, C23, IQGAP1, and UBF1 which participate in important cellular processes such as cell cycle regulation, ribosomal synthesis, spindle assembly, growth, cell survival, and rRNA transcription, did not ameliorate TGHQ cytotoxicity. Through our studies, we recognized that TGHQ have a prominent impact in the PAR interactome by promoting the differential PAR association of multiple proteins. We speculate that TGHQ-induced PARP-1 hyperactivation promotes a deep alteration in the PAR network, leading to multiple cellular events which in combination result in cell death. The studies performed in this thesis not only reveal novel interactions and pathways that are regulated by PAR, but also show the specific proteins that might participate in mechanisms in which PARP-1 activation result in cell injury.
    • Differences in Healthcare Expenditure, Health-Related Quality of Life, Perceived Quality, Medication Access, and Provider Respect Between Opioid and Non-Opioid Users Among a National Sample of Community-Based Older United States Adults with Pain, 2015

      Warholak, Terri; Axon, David Rhys; Slack, Marion; Lee, Jeannie; Barraza, Leila (The University of Arizona., 2019)
      Introduction: Increasing numbers of older adults, coupled with increasing use of opioids and opioid-related deaths, presents considerable healthcare challenges in the United States (US). This study compared the healthcare expenditure, health-related quality of life (HRQoL), perceived healthcare quality, access to medications, and perceived respect shown by provider between older US adults (≥50 years) with pain who use opioid medications and those who do not use opioid medications. Methods: This study employed a retrospective, cross-sectional database design using Medical Expenditure Panel Survey (MEPS) data from 2015. Eligible participants were those alive for the calendar year, aged 50 years or older, and reported having chronic pain in the past four weeks. The key independent variable was opioid use status (opioid users were defined as those who had a Multum Lexicon therapeutic class code of 60 or 191; the remainder was deemed non-opioid users). Hierarchical linear regression models were constructed to assess healthcare expenditures (inpatient, outpatient, office-based, emergency room, prescription medications, other, and total), HRQoL (short form 12 version 2 physical component summary [SF-12v2-PCS], short form 12 version 2 mental component summary [SF-12v2-MCS], and Kessler 6 [K6] scores), and perceived quality between opioid users and non-opioid users, adjusting for appropriate covariates. Hierarchical logistic regression models were constructed to assess access to medications (unable to receive prescription medications, delayed receiving prescription medications) and perceived respect shown by provider between opioid users and non-opioid users, adjusting for appropriate covariates. National estimates were obtained by adjusting for the complex survey design of MEPS. An alpha level of 0.05 was set a priori for all analyses. All analyses were conducted using SAS version 9.4. This study was deemed exempt from the human subject protection program. Results: The study cohort consisted of 4,759 subjects - 1,525 opioid users and 3,234 non-opioid users. The weighted total number of non-institutionalized adults alive aged 50 or older with pain in the US in the year 2015 was 50,898,592 - 16,757,516 (32.9%) were opioid users and 34,141,076 (67.1%) were non-opioid users. Opioid use was associated with all personal characteristics (p<0.05), except gender and race. After adjustment for predisposing, enabling, need, personal health practices, and external environmental factors, opioid users had 61% greater outpatient expenditure (β=0.477, p<0.0001), 69% greater office-based expenditure (β=0.524, p<0.0001), 14% greater emergency room expenditure (β=0.131, p=0.0045), 63% greater prescription medication expenditure (β=0.486, p<0.0001), 29% greater other healthcare expenditure (β=0.251, p=0.0002), 105% greater total healthcare expenditure (β=0.718, p<0.0001), and 15% greater perceived healthcare quality scores (β=0.154, p=0.0286). After adjustment for predisposing, enabling, need, personal health practices, and external environmental factors, older US adults (≥50 years) with pain in the past four weeks who perceived their provider showed them respect were 1.4 (95% CI = 1.0, 1.8) times more likely to be opioid users than non-opioid users. There was no significant difference between opioid users and non-opioid users for inpatient expenditures, SF-12v2-PCS scores, SF-12v2-MCS scores, K6 scores, or access to medications (p>0.05). Conclusions: This study estimated that the number of older US adults (≥50 years) with pain in 2015 was approximately 51 million, and that the estimated prevalence of opioid use among older US adults (≥50 years) with pain in 2015 was approximately 17 million. Opioid use was associated with all personal characteristics, except gender and race. Adjusted healthcare expenditures were greater among opioid users compared to non-opioid users for all categories of expenditure, except inpatient expenditures. Adjusted perceived healthcare quality measures and perceived respect shown by healthcare provider measures were greater among opioid users compared to non-opioid users. Adjusted health-related quality of life measures and access to prescription medication measures were not associated with opioid use status. Future research is warranted to investigate reasons why some of these findings exist, and to explore these variables in greater depth, over longer periods of time, and in additional populations.
    • Freeform Optical Design Methodologies and Surface Metrology Using Deflectometry

      Kim, Dae Wook; Trumper, Isaac; Dubin, Matthew B.; Liang, Rongguang (The University of Arizona., 2019)
      This dissertation covers contributions to the fields of optical design and optical testing using freeform optics applied to astronomical optics. A science goal based motivation for why these technologies are important to develop in the context of the next generation of astronomical optics is presented in Chapter 2. This is followed by a summary of the work on a method to guide the selection of freeform surfaces in an optical design, given in Chapter 3 and in detail in Appendix A. Freeform surfaces are again leveraged in a unique manner by applying them to dynamic optical configurations, summarized in Chapter 4 and in detail in Appendix B. Chapter 5 summarizes the contribution of an instantaneous phase shifting deflectometry method that leverages color multiplexing and Fourier transform based analysis to the field of freeform and dynamic optical testing, which is given in further detail in Appendix C. This methodology is applied to the dynamic calibration of a deformable mirror surface, summarized in Chapter 6 and in detail in Appendix D. The key results from each of the contributions to the two fields metrology and design of freeform optics are presented in the summary chapters, with further connections to the broader context of freeform surfaces and dynamic metrology applied to astronomical optics.
    • Application of Polarimetry to Surveillance and Underwater Imaging

      Pau, Stanley; Ding, Yitian; Ashok, Amit; Chipman, Russell A. (The University of Arizona., 2019)
      This dissertation discusses two major topics: The separation of images with polarimetric imaging and the total internal reflection under water. It is organized as follows. Chapter 1 is the introduction and it talks about the basics of polarization optics. It starts with the Maxwell’s equations to derive the wave equation of plane electromagnetic waves, and then talks about the Jones vectors and Jones matrices, which describe the polarization properties of monochromatic waves and of optical components that are illuminated by the waves. The Fresnel reflection is then discussed using the Jones calculus. After that, the discussion is extended to polychromatic light, where the Stokes vectors and Mueller matrices are used instead. The Mueller matrices for Fresnel reflection is given at last. In chapter 2 and chapter 3, image separation with unpolarized objects and polarized objects are studied. The Mueller matrix equations for scenes with various reflectors are derived, and the algorithms that solve the corresponding scalar equations for separated images are developed. In the algorithms, the correlation between images is evaluated by a metric function – edge overlap – that is developed specifically for this image separation application. A variety of test scenes and separation results are shown to demonstrate the advantages and disadvantages of the proposed separation method. In addition, a limit of this method imposed by the signal-to-noise ratio of the captured images is estimated. At the end, the extension of the proposed method to scenes with multiple reflectors are discussed. Chapter 4 serves are the introduction to the second topic. It goes over the situations in Nature that total internal reflection could happen, and briefly studies the related polarization effects. Chapter 5 and chapter 6 then focus on the total internal reflection at the water-air interface. In chapter 5, the conversion from linearly polarized light to circularly/elliptically polarized light in total internal reflection is studied, and a maximum conversion efficiency is calculated. A maximum degree-of-circular-polarization circle is predicted in the captured reflected image, and the relation between the degree-of-circular-polarization of the reflected light and the surface properties of the captured objects in the image are found to resemble the Umov effect. Meanwhile, chapter 6 calculates the same conversion efficiency across a water bubble and computes various “average” conversion efficiencies. Finally, chapter 7 summarizes the above studies. The study of image separation has found applications in surveillance while the study of total internal reflection is currently mainly of academic interests. However, the additional information in the polarization properties of light has not been fully appreciated and made use of in most optical systems. We hope that the studies in this dissertation could shine a light on the future applications of polarization optics.
    • Freeform Metrology Using Deflectometry

      Kim, Dae Wook; Graves, Logan Rodriguez; Smith, Gregory; Schwiegerling, James; Koshel, R. John (The University of Arizona., 2019)
      Precision freeform optics are finding increased usage in new optical systems. Deflectometry is a non-null optical metrology method that has great application potential to be a measurement method for freeform and standard optics, offering a wide slope dynamic range and excellent accuracy and precision. The technique utilizes a known source which emits rays of light that are deflected by the unit under test (UUT) and are captured by a recording camera. By knowing the precise location of the source, the ray intercepts at the UUT, and the camera, the local surface slopes of the UUT can be determined and integrated to obtain a reconstructed surface. This study investigates three major topics to improve deflectometry and identify new Deflectometric based techniques. The first topic explored is a software-based method for an iterative surface reconstruction process. Deflectometry relies on determining the local surface slopes of the UUT by precisely knowing the ray intercept locations at the surface. Any error in the assumed surface model therefore directly reduces the reconstructed surface accuracy. A new processing method was developed called model-free deflectometry, which requires no optical surface model, and instead iteratively reconstructs the optical surface leading to improved final reconstruction accuracy. The method was used to reduce departure of a freeform optic from interferometric results from 15.80 𝜇m root-mean-square (RMS) using model-based deflectometry down to 5.20 𝜇m RMS with the model-free method developed. Further, most of the 5.20 𝜇m RMS residual departure was explained using a simulation to model the inherent noise present from hardware limitations. The second topic is a deflectometry system configuration which generates a virtual 2π steradian measurement volume, enabling full aperture deflectometry measurements of previously unmeasurable flat and convex freeform optics. The technique utilizes a source tilted over the UUT, enabling at least a partial aperture test. However, by clocking the UUT, a series of virtual sources are generated, which when considered as a whole, create a virtual source enclosure around the UUT allowing for a full aperture test. The method was shown to have accuracy similar to an interferometric test for a fast F/1.26 convex sphere and successfully tested a highly freeform Alvarez lens. Lastly, a power scalable, time-modulated high stability infrared source is explored for infrared deflectometry. The new source is an integrating box design with a precision emission area machine cut into an aluminum box. The light sources are modular high-efficiency resistive alloy membranes held in small caps. The design allows for power scaling by adding or removing caps from the source design. The caps are powered in parallel and are modulated at approximately 1 Hz to allow for signal isolation, thereby greatly improving signal to noise ratio. The new source was compared with a traditional tungsten source, both run at the same power output, and the source stability and geometry compared. Several common optical surfaces were tested with both sources to compare the accuracy and precision of the sources. It was found that the integrating box features a significant improvement in performance.
    • Polarization Aberrations in Coronagraphs

      Chipman, Russell A.; Davis, Jeffrey Mitchell; Breckinridge, James B.; Schwiegerling, James (The University of Arizona., 2019)
      In the search for habitable extrasolar planets, the ability to separate and detect the dim planet's light from its much brighter host star is paramount. The inherent polarization properties of optical systems can lead to small but significant deviations from ideal imaging behavior, possibly hindering the ability of that system to detect exoplanets. In this work, the polarization aberrations in a telescope/coronagraph optical system are modeled with polarization ray tracing software. The effect of these polarization aberrations on the coronagraph's ability to suppress on-axis starlight is analyzed, and an algorithm for mitigation of some of the polarization aberrations is provided. This dissertation lays the foundation for modeling and analyzing polarization aberrations in telescope/coronagraph systems and shows that, in the absence of adaptive optics, both isotropic and anisotropic polarization aberrations degrade a coronagraph's ability to suppress starlight. The contrast is a measure of on-axis starlight suppression. With isotropic polarization aberrations, the contrast is degraded by two orders of magnitude relative to the ideal, polarization aberration-free case. Anisotropy modeled on the primary mirror further degraded the contrast by two orders of magnitude relative to the isotropic case. Modeling polarization aberrations shows how coatings negatively affect the possible contrast of a coronagraph.
    • Efficient Data Acquisition and Parameter Estimation for Gamma-Ray Detectors and Other Sensors

      Furenlid, Lars R.; Ruiz Gonzalez, Maria del Carmen; Kupinski, Matthew; Peng, Leilei (The University of Arizona., 2019)
      Gamma-ray detection is extensively used in areas such as astronomy, nuclear physics, and medical imaging. There are many different ways a gamma-ray can interact with a detector; for instance, it can transfer just a portion of its energy, or it can transfer all its energy, and in both cases produce a complex cascade of ionization events. The amount of information that can be extracted from each event signal depends on the way the data is acquired and the method utilized to estimate gamma-ray parameters. Parameters that can be estimated from the interaction event include the energy deposited, direction, position of interaction, and time of interaction. Energy, concentration, and distribution of the source can then be estimated from this data. We explored the use of Fisher information to quantify the amount of energy and timing information in digitized gamma-ray signals, and a related parameter called the Cramer-Rao lower bound to estimate the best resolution a detector can achieve. We developed an energy and timing estimation method based on maximum-likelihood. Based on the Fisher information analysis and maximum-likelihood estimation results, we developed a novel analog-to-digital conversion method for gamma-ray signals based on sigma-delta modulation that maintains statistical information on gamma-ray waveforms, but is less complex and less costly compared to conventional analog-to-digital converters. Lastly, we designed, built, and characterized a sigma-delta-modulation-based read-out electronics board for gamma-ray cameras. The novel read-out architecture allows to implement waveform digitization and acquisition in imaging systems with a large number of channels and with different types of sensors, such as photomultiplier tubes, avalanche photodiodes, and silicon photomultipliers.
    • A 7.5X Afocal Zoom Lens Design and Kernel Aberration Correction Using Reversed Ray Tracing Methods

      Sasián, José M.; Zhou, Xi; Schwiegerling, James; Liang, Rongguang (The University of Arizona., 2019)
      This thesis presents a design of an afocal 7.5X zoom lens with maximum resolution of 0.68μm followed by a reversed ray trace method to show and correct kernel aberrations in zoom lens, with some examples. In Chapter 1, some fundamentals of geometric optics are introduced to help understanding lens design, including terminology, aberration theory, and methods to quantify a lens system performance. Chapter 2 starts with a brief introduction on zoom lens system, which includes characterizing the functionalities of different moving groups, the variator and the compensator, different types of zoom lens configurations, evolution of zoom types and lastly several novel applications of zoom lenses. In Chapter 3, design of a 7.5x afocal zoom with maximum resolution of 0.68μm is presented. The process starts with finding a thin lens solution, then a monochromatic thick lens solution; finally a diffraction limited polychromatic thick lens solution is achieved. In Chapter 4, a reversed ray trace method is introduced to identify and correct the kernel aberrations in zoom lens. Some patent examples are used to show kernel aberrations with the reversed ray trace method. Then two optimization examples of the kernel aberrations are given at the end. Chapter 5 concludes the work presented in this thesis, with some suggestions for possible future works.
    • Lateral Divergence in High Power Laser Diodes: Method of Analysis for Assessing Contributing Factors

      Fallahi, Mahmoud; Vail, Nicholas; Pau, Stanley; Crowley, Mark (The University of Arizona., 2019)
      Lateral far field blooming or slow axis divergence is a common problem of high-power diode lasers and there are many different factors that contribute. Some of the major factors include temperature, carrier-induced effects, high order modes, mode types, and optical confinement. In this study, these properties were characterized and quantified in order to build a model to assess and simulate lateral divergence. A novel device called a spectral mapper was built to separate out lateral and longitudinal modes and their changes as current is varied. The collected and calculated data was input into LaserMOD, where simulations were run to determine the extent to which core width, mode number and refractive index changes modify the divergence of the device. While the modelling software was unable to support large numbers of modes due to weak confinement and also underestimated refractive index change in multimodal devices, the model and simulations were still able to quantify that more modes led to more lateral divergence. These tests and models can be used to improve coupling performance and hopefully provide insight into how high-power laser diodes can be further integrated with fiber lasers.
    • Simulation of Phase Measuring Deflectometry of Freeform Surfaces

      Schwiegerling, James; Tseng, Chao-Hsiung; Kim, Daewook; Liang, Rongguang (The University of Arizona., 2019)
      Optical three-dimensional shape metrology has become a key technology in scientific and industrial applications. Phase Measuring Deflectometry (PMD)is one optical three-dimensional shape metrology technique which is based on two-dimensional fringe patterns measurements for specular reflecting surfaces. There are several configurations of PMD to measure the arbitrary specular surfaces. Here, a single camera is used to capture the reflected image of a single LCD monitor to construct the deflectometry system. Distance laser sensors, multiple cameras, and multiple monitors will not be considered here. This investigation focuses on creating simulated PMD images for an arbitrary specular surface. Such images are useful for testing slope calculations and surface reconstruction algorithms. System geometry calibration and an inverse ray-tracing algorithm are explored. This thesis demonstrates the preliminary results of PMD for a flat mirror, a concave mirror and a freeform surface with the phase shifting method. The specific feature of the image simulation shows the inverse ray-tracing can deduce the captured image correctly. Included is a discussion about the ambiguity of fringe numbers and the uncertainty of the phase value calculation with insufficient fringe sampling.