Now showing items 21-40 of 71219

    • Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs): Plastics for Infrared Imaging and Photonics

      Pyun, Jeffrey; Kleine, Tristan; Norwood, Robert A.; Glass, Richard S.; Njardarson, Jon T. (The University of Arizona., 2019)
      This dissertation contains five chapters describing recent advances in the use of a new class of polymeric materials (Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs)) for infrared imaging and photonics. Plastics are generally not used for these applications given their typically high optical losses at these wavelengths and low refractive indices. CHIPs are a revolutionary class of materials that are composed of a high loading of chalcogen moieties that are copolymerized with organic monomers into the backbone of the polymer. The large chalcogen content in CHIPs enables IR transparency and high refractive indices (n), whereas the organic comonomers afford solution and melt processablility making these materials highly attractive for use in the aforementioned applications. The last chapter focuses on the development of a novel photopolymer for use in photonic interconnects operating at telecommunication wavelengths. This chapter lays the groundwork for using this photopolymer in “smart print” technologies for optical communications. The first chapter is a review on the fundamentals and applications of infrared imaging, the current materials used as optical elements in those systems, and examples of polymeric materials that have been developed for the same purpose. IR imaging has numerous applications ranging from medical diagnostics to autonomous vehicle technologies, and is used frequently in the military for night vision. There is a growing consumer market for IR cameras as well, now that the cost of certain components has been reduced. However, expensive semiconductor materials are still used as the optical components. Consequently, there is a desire to replace semiconductors with cheaper, easier to work with plastics. CHIPs address this need as they are more IR transparent than conventional plastics and are amenable to conventional thermoplastic reforming techniques. These unique features of CHIPs are a result of the chemistry termed “inverse vulcanization” used to prepare them. The inverse vulcanization process uses elemental sulfur as a comonomer and reaction medium. At high temperatures, elemental sulfur is homolytically ring opened, resulting in a high concentration of sulfur radicals which then react with other chalcogens/organic vinylic comonomers. The resulting polymeric material contains a high content of IR transparent polysulfur bonds which is the basis for IR transparency in CHIPs. The second chapter describes the synthesis of a new organic comonomer for inverse vulcanization designed to improve the thermomechanical properties of CHIPs. Early CHIPs materials prepared using 1,3-di-isopropenylbenzene (DIB) suffered from low glass transition temperatures resulting in a narrow use range. To address this issue 1,3,5-tri-isopropenyl benzene (TIB) was synthesized and used in inverse vulcanization reactions. The higher favg (number of crosslinkable moieties per monomer unit) associated with TIB afforded a more densely crosslinked material according to dynamic rheological experiments. As expected, this increased crosslink density resulted in CHIPs with dramatically improved glass transition temperatures (approximately twice that of their DIB based analogues) exceeding Tg > 100 °C. Despite being highly crosslinked, this new material still exhibited the self-healing properties previously demonstrated for DIB based CHIPs. Most importantly, this new CHIPs material was similarly transparent in the mid wave IR to DIB based CHIPs. This work demonstrated that the thermomechanical properties of CHIPs could be adjusted to fit the demands of practical applications without sacrificing desirable optical properties. The third chapter explores the method used to further increase the refractive index of CHIPs materials. Refractive index is a volume averaged bulk property, thus higher loadings of sulfur result in higher refractive indices for CHIPs. However, the maximum refractive index possible is limited by the amount (~85 wt%) of sulfur that can be efficiently incorporated into CHIPs. Therefore, a higher refractive index chalcogen must be used to realize higher n. Tellurium is mildly toxic and exceedingly expensive, so selenium was chosen instead. The enabling discovery was that elemental selenium reacts with ring opened sulfur species, generating a reactive mixed chalcogen in situ, that copolymerizes with organic crosslinkers. This enabled preparation of CHIPs materials with n ≤ 2.1 demonstrating a marked increase over previously synthesized CHIPs materials. The expected mid wave IR transparency was observed and evaluated by IR imaging experiments as well. Most significantly, certain compositions were found to be solution processable. Access to soluble CHIPs with high refractive indices is critical for the solution-based fabrication of various photonic devices. Only one such device will be discussed in this dissertation, but other examples are currently under development. The preparation and characterization of 1D photonic crystals (1D PhCs) utilizing selenium containing CHIPs is the topic of the fourth chapter. 1D PhCs are dielectric devices assembled with alternating layers of high and low refractive index material. Layer thickness determines the λmax of the photonic bandgap while the difference in refractive index (Δn) between layers affects the magnitude of reflection. In this design, larger Δn values facilitate highly reflective mirrors assembled with only a few layers. Consequently, various combinations of metal oxides are often used to achieve large Δn. However, entirely inorganic 1D PhCs are brittle, limiting their use in certain applications, and why wholly polymeric 1D PhCs are of great interest as an alternative design. Fabrication of such devices is complicated by the need to generate a large number of layers to offset the typically small Δn values observed in polymeric 1D PhCs. This issue is addressed by employing ultra-high refractive index CHIPs as one of the layers. 1D PhCs were prepared by spin coating alternating layers of selenium containing CHIPs (high refractive index layer) and cellulose acetate (low refractive index layer). Devices fabricated in this manner were shown to possess >90% reflection with just 11 bilayers, and whose band gap was tuned across the near-infrared (1000-2000 nm). The fifth chapter is devoted to the preparation of long wave IR (LWIR) transparent CHIPs. Imaging in the LWIR is significantly cheaper than in the mid wave IR, and thus attractive for a variety of consumer applications. CHIPs are transparent in the mid wave IR as a result of low C-H bond content, but this does not necessarily translate to LWIR transparency. This is because the LWIR overlaps with the fingerprint region of the infrared spectrum which encompasses a broader range of vibrational absorption modes. Consequently, even the small amount of organic comonomer present in CHIPs results in opaque materials at longer wavelengths. Interestingly, some organic polymers, like polyethylene, are remarkably transparent over much of the LWIR. Polyethylene itself is not suited towards use as a broadband IR optic due to its polycrystallinity, but indicated polymeric materials could in principle be designed with adequate transparency in this region. To this end, simulated FTIR spectra of various model compounds representative of the corresponding polymeric repeat unit were used to guide the design of LWIR transparent CHIPs. Ultimately, a dimer based on the [2+2] cycloaddition of 2,5-norbornadiene (resulting in the monomer termed NBD2) emerged as a monomer amenable to inverse vulcanization chemistry and expected to possess improved LWIR transparency. Melt cast windows of CHIPs containing NBD2 or DIB as the organic crosslinker were then prepared with the same thickness and compared in LWIR imaging experiments. The DIB based CHIPs material was opaque at these wavelengths, while the new NBD2 based CHIPs material afforded significantly improved transparency. In the future, this methodology will be expanded to develop more CHIP materials that are suitable for LWIR imaging applications. The sixth chapter represents a departure from an emphasis on mid-IR transparent materials. Instead, the focus is development of materials for photonics applications at wavelengths relevant to the telecommunications industry (1310 and 1550 nm). In this work, a novel photopolymer (poly(SBOC)) was prepared and demonstrated as a material for fabrication of photonic interconnects. These devices require a high refractive index medium through which light propagates to be surrounded by lower refractive index material. Such patterning is typically achieved through photolithography and a number of solvent development/etching steps. Poly(SBOC) simplifies this process since permanent refractive index changes with high resolution are generated by direct laser writing in dry polymer films. Optical power attenuation through the device (propagation loss) is an important metric of photonic interconnects. To assess this for poly(SBOC), waveguides were fabricated and characterized by the cut back method. The propagation losses observed were ~2 dB/cm and commensurate to values typically observed for hydrocarbon based waveguides. The promising results from this project have resulted in a collaboration with the AIM Photonics program in the College of Optical Sciences at The University of Arizona to develop “smart write” photonic interconnects.
    • The Spectrum of Asian Monsoon Variability: An Investigation of Low-Frequency Variability in Paleoclimate Proxies and Climate Models

      Overpeck, Jonathan T.; Thompson, Diane M.; Loope, Garrison; Quade, Jay; Meko, David M.; Yin, Jianjun (The University of Arizona., 2019)
      In this work we investigate the low-frequency (decadal-centennial) variability of the climate system in Monsoon Asia using a combination of instrumental, paleoclimate proxy, and climate model data. Understanding this critical component of the climate system is essential for accurately assessing the risk of low-probability extreme events such as megadroughts that may arise from the interaction of anthropogenic climate forcing and natural internal variability (Ault et al., 2014). In Appendix A, we use a network of hydroclimate proxies from Monsoon Asia as a case study to compare low-frequency variability in paleo-data to climate model simulations. We take a proxy system modeling approach, using climate output variables from isotope-enabled runs of iCESM, isoGSM, and iCAM5, to simulate synthetic proxy records, which creates a common ground for the comparison. We find that the pseudoproxies based on iCESM do not accurately capture the relative strength of multidecadal-century scale variability in the paleoclimate data. We find that the pseudoproxies based on isoGSM and iCAM5, which are constrained by instrumental observations, appear to match the scaling pattern of variability found in the proxy records. Our results indicate that state-of-the-art, fully coupled climate models are not able to generate a sufficient amount of multidecadal-century scale variability in hydroclimate. We find that one major source of multidecadal scale variability found in the proxies but not in the models comes from the combined interactions among the monsoon, El Niño-Southern Oscillation (ENSO), and the Indian Ocean sea-surface temperature variability. In Appendix B, we investigate the low-frequency variability found in multiproxy ENSO reconstructions, with the goal of understanding how this dominant source of hydroclimate variability on interannual scales may impact teleconnected regions on decadal-centennial time scales. Previous multiproxy reconstructions of ENSO have found a large amount of low-frequency variability but the time series of this low-frequency variability rarely matches between studies. We investigate potential biases in reconstructions of ENSO from the number and geographical distribution of sites, age model uncertainty, and sources of noise present in the individual proxy records. We conduct a series of sensitivity experiments using pseudoproxies to demonstrate that these factors have the potential to bias the spectrum of reconstructions causing them to overestimate the relative amount of decadal-century scale variability in the tropical Pacific. This could help explain why multiproxy ENSO reconstructions show greater multidecadal-century scale variability than is found in observations or climate model simulations. In Appendix C, we introduce a new paleo-monsoon proxy covering the last 2600 years based on grain size variability in a sediment core from Pale Daha, a small lake in western Nepal. We demonstrate that variability in grain size distribution over the last century matches with low-frequency precipitation variability found in 20th Century Reanalysis data (Compo et al., 2011). We identify a major pluvial from 950-1300 CE that matches with a similar pluvial in nearby Sahiya Cave (Sinha et al., 2015), and with increased monsoon circulation over the northern Arabian Sea (Anderson et al., 2002; Gupta et al., 2005). We find evidence that the monsoon precipitation at the site over the last 150 years has been particularly strong as compared to relatively weak monsoon rains from 1300-1800 CE. We then compare the trends found in paleo-monsoon proxies over the last 150 years and find that much of the apparently contradictory trends may be explained by the projected circulation and precipitation responses to anthropogenic forcing. This new interpretation is based on a simulated northward shift in circulation that may increase the relative fraction of precipitation at proxy sites received from the Arabian Sea and decrease the fraction from the Bay of Bengal. This shift in circulation could produce the trend in precipitation stable isotopes found in isotope based paleo-monsoon proxies. If true, these findings indicate that the South Asian Monsoon may already be experiencing the effects of anthropogenic climate change to a degree not yet fully appreciated, and that these changes are likely to continue into the future.
    • The Origins of Biodiversity Patterns in Vertebrates: New Insights Into Old Questions

      Wiens, John J.; Miller, Elizabeth Christina; Sanderson, Michael; Ferriere, Regis; Flessa, Karl (The University of Arizona., 2019)
      Species richness varies greatly among habitats, geography, and groups of organisms. What factors are responsible for these differences, and how did these differences arise over time? Within a clade, species are added through speciation and removed through extinction. Within a region or habitat, species can also be added through colonization. Organismal traits or environmental factors may influence richness indirectly by affecting speciation, extinction, or colonization. The goal of this dissertation is to investigate how these three processes have varied over time to form the species richness patterns observed today. To do this, I take advantage of four recent developments in evolutionary biology: (1) the collection of DNA sequence data across many taxa; (2) the time-calibration of molecular phylogenies; (3) the increased complexity of models of diversification and ancestral reconstruction; and (4) the aggregation of taxonomic, geographic, paleontological and trait data into public databases. In Appendix A, we investigate the disparity in amniote species richness between marine and nonmarine habitats. We found that, surprisingly, there was no systematic difference in rates associated with habitats. However, there was a strong relationship between species richness and the timing of habitat transition. Many marine transitions went extinct, and as a consequence almost all living marine lineages are Cenozoic in age. In contrast, amniotes have occupied land uninterrupted for over 300 million years. We concluded that extinction and time interact to produce the richness disparity between marine and nonmarine habitats. In Appendix B, we investigated the causes of the peak in marine richness at the Central Indo-Pacific (CIP) hotspot using percomorph fishes as a focal clade. We found that diversification rates were similar among warm oceans, and highest in cold oceans. The high diversity of the CIP is due to many lineages that colonized from 34–5.3 million years ago and then diversified in-situ. Other oceans have fewer colonizing lineages and/or more recent colonization leaving limited time for in-situ diversification. In Appendix C, we investigated the causes of the latitudinal diversity gradient on continents, using freshwater ray-finned fishes as a model clade. Colonization time explained 2–5 times more of the variation in species richness than diversification rates among 3,000+ freshwater drainage basins. The Neotropics is species-rich because it has supported steady diversification for ~100 million years, while other tropical regions have had periods of low diversification. While high-latitude lineages that are dominant today did not arrive until the Cenozoic, they diversified at a comparable or higher rate than tropical lineages. Finally, in Appendix D we tested the longstanding hypothesis that sexual dichromatism increases diversification rates. We tested this hypothesis at three phylogenetic scales: across all ray-finned fishes, within individual clades, and within nested subclades of the largest clades. We found no difference in rates between monochromatic and dichromatic fishes at the scale of all fishes. Only a few clades showed a relationship with dichromatism and diversification. Surprisingly, these clades did not include the subjects of classic population-level studies (e.g. cichlids). Support for such a relationship increased in most smaller subclades examined. We concluded that when sexual dichromatism influences diversification, its effects will be localized to small phylogenetic scales. Overall, the works in this dissertation yield new insights into longstanding problems in evolution and ecology.
    • Environmental Fate and Toxicity of III-V Engineered Nanoparticles in Semiconductor Manufacturing

      Sierra-Alvarez, Reyes; Field, James A.; Nguyen, Chi Huynh; Farrell, James; Curry, Joan E. (The University of Arizona., 2019)
      Engineered nanoparticles (NPs) have many unique electronic, chemical, and optical properties. Gallium arsenide (GaAs) NPs and indium arsenide (InAs) NPs are being considered in different semiconductors and electronic devices due to their favorable properties such as high electron mobility with wide and adjustable band gaps and their reduced power consumption. Polishing of thin films in a process known as chemical and mechanical planarization (CMP) could lead potentially to the release of byproducts from GaAs and InAs, such as soluble III-V materials (Ga, In, and arsenic (As) species) and particulate III-V materials (GaAs NPs, InAs NPs, gallium oxide (Ga2O3), indium oxide (In2O3)) into the wastewater stream. Furthermore, the CMP process utilizes cerium oxide (CeO2), silica (SiO2), and alumina (Al2O3) as abrasive particles in slurries to polish and create flat surfaces. As a result, CeO2, SiO2, and Al2O3 NPs will also be present in the waste streams of the semiconductor industry. Additionally, some NPs can promote the transport of toxic chemicals into cells through the “Trojan Horse” effect, which can potentially alter the toxicity of the NPs via adsorbed chemicals. Among the soluble III-V ions, arsenic is a concern for the Trojan Horse effect because it is a highly toxic and carcinogenic element with soluble species that can become adsorbed onto NP surfaces. Although the toxicity of soluble arsenic species is well established, little is known about the potential toxicity of other soluble III-V materials and III-V NPs. Therefore, it is important to study and understand the environmental fate and toxicity of these materials. The objectives of this work are to investigate the potential toxicity and environmental fate of III-V nanomaterials and byproducts that could be formed in CMP slurries of semiconductor manufacturing effluents as well as to study the impact of CeO2 NPs on the sorption and toxicity of As species. The acute toxicity of GaAs, InAs, Ga2O3, and In2O3 particulates was investigated using two microbial assays targeting methanogenic archaea and the marine bacterium, Allivibrio fischeri. The results showed that GaAs and InAs NPs were acutely toxic towards these microorganisms while Ga2O3 and In2O3 NPs were not. The release of soluble arsenic species from arsenide NPs was shown to play a key role in the toxic effect of the arsenide NPs. Their toxicity increased with decreasing particle size and with increasing time because of the progressive corrosion of the NPs in the aqueous bioassay medium. In summary, the toxicity exerted by the arsenide NPs under environmental conditions will vary depending upon the particle size, dissolution time, and aqueous chemistry. In addition to microbial toxicity, these materials could cause toxic effects to human health. The toxic effects of Ga-based and In-based NPs (GaAs, InAs, Ga2O3, and In2O3) as well as soluble III-V salts (AsIII, AsV, GaIII, and InIII) on human bronchial epithelial cells (16HBE14o-) were evaluated using an impedance-based real time cell analyzing (RTCA) system. The results showed that only dissolved arsenic (AsIII and AsV) and arsenide particulate compounds caused significant inhibition at low concentrations (IC50 values after 16 h of exposure (16 h-IC50): 2.4 mg AsIII/L, 4.5 mg AsV/L, 6.2 mg GaAs NPs/L, and 68 mg InAs NPs/L). Similar to the case with the microbial toxicity, the cytotoxicity of the arsenide NPs to 16HBE14o- cells was mainly caused by dissolution of toxic As species (mostly AsIII). On the other hand, the soluble salt, GaIII-citrate, and Ga2O3 NPs caused mild inhibition while InIII-citrate and In2O3 NPs were not toxic at the concentrations tested (16 h-IC50 value: 260 mg Ga2O3 NPs/L), while InIII-citrate and In2O3 NPs were not toxic at the concentration tested (16 h-IC50 value: > 300 mg In2O3 NPs/L). In conclusion, GaAs NPs and, to a lesser extent InAs NPs, display toxicity to human lung cells and the adverse effects are expected to increase with increasing NP dissolution. Besides Ga- and In-based NPs, abrasive NPs used in CMP slurries (i.e. CeO2, Al2O3, colloidal SiO2 (c-SiO2), and fumed SiO2 (f-SiO2)) will be present in semiconductor effluents and they could potentially be toxic to microbial communities and human health. The toxic effects of well-characterized model CMP slurries on the marine bacterium A. fischeri and human bronchial epithelial cells 16HBE14o- cells were investigated. The results showed that f-SiO2 and CeO2 slurries did not cause acute toxicity on A. fischeri at concentrations as high as 1136 and 909 mg/L, respectively. In contrast, c-SiO2 and Al2O3 caused about 30% inhibition on microbial activity after 30 min of exposure at relatively high concentration (1364 mg c-SiO2/L and 1364 mg Al2O3/L). Lung cells were more sensitive to exposure to some of these inorganic oxide NPs. High concentrations (250 and 500 mg/L) of c-SiO2 and f-SiO2 slurries led to lung cell death in the RTCA assay. On the other hand, CeO2 and Al2O3 slurries were either not inhibitory or only showed limited inhibitory effect on 16HBE14o- cells after 24 h of exposure. As a whole, the results indicate that the abrasive NPs used in CMP are not likely to cause acute environmental and health risks at the low concentrations expected in surface water (< 1 mg/L). The presence of CMP NPs together with III-V soluble species can lead to emerging environmental and health problems. This study showed that CeO2 NPs effectively decreased the concentration of available AsIII in the culture medium through adsorption; hence showing the effect completely opposite of the “Trojan Horse” effect. Additionally, this work showed that internalization of CeO2 NPs by human lung cells was observed in vesicles (most likely lysosomes). Taken as a whole, this dissertation demonstrates that GaAs NPs, and to a lesser extent InAs NPs, cause acute toxicity to the studied microbial targets and to human lung cells due to the corrosion of the nanomaterials in the aqueous environment, and the ensuing release of toxic AsIII. Other nanomaterials anticipated in CMP effluents (i.e. Ga2O3 NPs and In2O3 NPs) were relatively non-toxic. Abrasive NPs like CeO2, Al2O3, c-SiO2, and f-SiO2 used in CMP slurries caused certain toxic effects to human bronchial epithelial cells at relatively high concentrations. The existence of CeO2 NPs along with soluble AsIII in waste effluent led to adsorption of AsIII onto CeO2 NPs that, as a result, decreased the toxicity of AsIII dramatically.
    • The Association Between Oral Health Care and A1c Levels in Health Center Diabetic Patients

      Barraza, Leila Fs; Thompson, Alicia M.; Barraza, Leila Fs; Rosales, Cecilia B.; Carrol, Stephanie R.; Zhou, Jin; La Chance, Gregory C. (The University of Arizona., 2019)
      BACKGROUND: Poor oral health is a problem. A big problem. Some are calling it an emerging crisis in the United States (US) (Politico, 2019). There is strong evidence that a person cannot be truly healthy if they have poor oral health, yet the medical and dental professions are divided when it comes to the provision of care. For the most part the medical profession treats the patient as if they do not have a mouth, and the dental profession treats the patient as if they do not have a body. Research indicates this historical division must stop. This becomes very apparent when the guidelines for the care of patients with diabetes are examined. This project sought to focus on the association between oral health care received by patients with diabetes and glycemic control as measured by HbA1c, and policy implications for the medical/dental divide as they pertain specifically to the treatment and care of people living with diabetes. OBJECTIVES: The dissertation aims were to: 1) Document access to oral healthcare within a large FQHC in Southwestern US to determine whether there were disparities in access by specific demographic constructs; 2) Document the level of oral healthcare being delivered to medical/dental patients with diabetes to determine if there is an optimal level of oral health care for adult patients with Type II Diabetes; and, 3) Document whether access to oral hygiene services improved glycemic control of patients with diabetes who were enrolled in a Diabetes Self Management Education (DSME) program compared to those who did not. METHODS: This quantitative study was a retrospective record review of 3,144 randomly selected patients with diabetes who were medical and dental patients at a large Southwestern Federally Qualified Health Center. RESULTS: There was a greater disparity in access to oral health care services within the FQHC than what was reported for the Nation (Oral Health, 2000). Within patients who identified as Hispanic ethnicity, only 19.2% accessed oral health care services in 2017, while 46.2% at the National level did so in 1993 (Oral Health, 2000, pg. 80). Fewer than 10% of all adult medical patients accessed oral health care services. Patients who only access dental services make it appear like a greater percentage of medical patients are accessing oral health care. Fewer than 5% of adult patients with diabetes, seen for oral health care services, received dental prophylaxis at least two times per year. HbA1c was significantly lower for patients who had received dental prophylaxis at least two times per year or ever received dental prophylaxis, than patients who never received dental prophylaxis (F=16.13, df = 1,476, p<.000). Patients who had never received dental prophylaxis were 2.98 times more likely to have uncontrolled diabetes as measured by HbA1c than were patients who had received this level of care (z=2.74, se = 1.19, p=.006). The odds of patients having uncontrolled diabetes who have never received preventive oral hygiene services ranged from 2.60 to 3.34 times higher than patients who had received oral hygiene services. No significant difference in HbA1c was observed between patients who received medical care only and patients who received both medical and dental care but had not received dental hygiene services (t=-1.04, df=2,566, p=0.297). The majority of medical and dental patients with diabetes (68.2%) never received preventive dental services. Patients with diabetes who were enrolled in the Diabetes Self-Management Education (DSME) program who accessed oral health hygiene care at least two times per year have statistically significantly lower average HbA1c than DSME enrolled patients who did not access oral hygiene care (7.51 vs. 9.21 & 9.29). Fewer than one third (31.8%) of patients with diabetes enrolled in the DSME program who accessed oral health services received preventive dental services such as a dental prophylaxis or periodontal treatment. There were no statistically significant differences between average HbA1c for patients who only received a dental prophylaxis (teeth cleaning) versus those who had received at least one periodontal service (7.27 vs. 7.45 for all patients with diabetes; 8.47 vs. 8.63 for DSME enrolled patients). This finding was surprising as almost all prior research has been focused only on periodontal treatment such as scaling and root planing. CONCLUSIONS: The results of this study indicate more pronounced disparities in access to oral health care within a FQHC than what are found within the population. Patients who are being treated for diabetes medically are unlikely to access preventive dental services (68%), even when the services are available. Patients who do not access preventive dental services have a greater likelihood of uncontrolled diabetes than those patients who do access these services. Patients enrolled in an accredited DSME program and who access preventive dental services have statistically significantly lower HbA1c than those who do not. Medical guidelines for the treatment of diabetes do not include specific recommendations on the frequency or type of oral health care patients with diabetes should receive. The results of this study provide additional support to the hypothesis that access to preventive dental services every six months could play a major role in the control of diabetes. The lack of training of medical professionals to conduct oral exams as part of their regular protocol precludes their ability to incorporate the mouth into their regular practice routine. The lack of training of dental professionals to understand the impact of poor oral health on the systemic health of their patients precludes their ability to consider the impact of oral health beyond the mouth. While there are efforts on both the medical and dental sides to break down the divide, we have not reached a tipping point where the barriers to integration are completely removed. The parity in access to oral health care insurance is a major barrier to the ability of patients with diabetes who receive medical care in an FQHC to access preventive dental services. This lack of access precludes patients from the ability to achieve optimal health. RECOMMENDATIONS: Federal legislation should be sought to revise the Public Health Practice Act to include a definition of preventive dental services and a focus on preventing oral disease rather than the treatment of emergent dental issues in Federally Qualified Health Centers. The American Diabetes Association and the American Dental Association should convene a workgroup to determine specific guidelines for the oral health care of patients with diabetes. Medical schools should adopt the Head, Ears, Eyes, Nose, Oral cavity, and Throat (HEENOT) protocol as the standard protocol for the regular exam of the head and teach all medical students to conduct the HEENOT. Medical providers should be taught how to utilize non-invasive, nonrestorative, medicinal methods to prevent and arrest tooth decay, such as the application of Silver Diamine Fluoride and glass ionomer sealants. Dental school curriculum should be developed to teach dental students about the oral/systemic connection and how the dental professional can monitor the health of patients as well as to work interprofessionally with the medical profession. State legislation should be sought that requires the coverage of preventive dental services for all ages by all health insurance providers.
    • Toward Joint Scene Understanding Using Deep Convolutional Neural Network: Object State, Depth, and Segmentation

      Rozenblit, Jerzy; Ditzler, Gregory; Peng, Kuo-Shiuan; Roveda, Janet (The University of Arizona., 2019)
      Semantic understanding is the foundation of an intelligent system in the field of computer vision. Particularly, the real-time usage of the automation systems, such as robotic vision, auto-driving, and surgical training applications, has been in high demand. The models require to capture this variability of scenes and their constituents (e.g., objects or depth) given the limited memory and computation resources. To achieve the goals of real-time usage in semantic understanding, we propose a series of novel methods for object state, depth, and segmentation in this dissertation. We first present a semantic object model for simplifying the object state detection process. We then propose a novel method of monocular depth estimation to retrieve the 3D information effectively. Lastly, this dissertation presents a multi-task model for semantic segmentation and depth estimation. We train and verify the proposed method by using two public datasets of outdoor scenes that are meant to be applied to auto-driving applications. Our method successfully achieves 60 frames per second with a competitive performance compared to the current state-of-the-art in the benchmark. In the empirical experiments, we have applied our method to a simulated laparoscopic surgical training system: Computer Assisted Surgical Trainer (CAST). One of the CAST training tasks, Peg Transfer Task, is selected to be the evaluation platform. In this experiment, our method has demonstrated promising results for supporting a real-world application in medicine.
    • Tracking Technology and Society along the Ottoman Anatolian Railroad, 1890-1914

      Darling, Linda T.; Schweig, Alexander; Clancy-Smith, Julia A.; Fortna, Benjamin C.; Weiner, Douglas (The University of Arizona., 2019)
      The construction of the Ottoman Anatolian Railroad, along with its extension, the Baghdad Railroad, is often considered a case of foreign-driven modernization and pseudo-colonial investment in the Ottoman Empire and is assigned primary importance as a diplomatic problem aggravating tensions between the European powers in the run-up to World War I. Far less scrutiny has been given to the railroad’s intersections with and effects on the fabric of Anatolian society. This dissertation not only fills this gap in the research, but also challenges the view of technological modernization as an alien imposition upon the Ottoman Empire. It argues for the participation of a variety of agents, including many locals both reacting to and involved in creating the social and economic transformations occurring around them. I argue that provincial Anatolian modernity was an ad hoc co-creation between multiple actors rather than something solely imposed from outside or from above by foreign powers or by the Ottoman state. My research addresses the period of the construction and the first two decades of the Anatolian Railroad’s operation (1890-1914) in three districts (sancaks) of Western and Central Anatolia in order to understand the social history of technology in the late Ottoman Empire. The railroad had a profound impact on numerous aspects of Ottoman society, including labor migration, urbanization, industrialization, refugee settlement, and the intensification of export agriculture. I use the theoretical lens of the social construction of technology to argue for the relevance of the use of the railroad to questions of its “ownership.” In addition, Actor Network Theory indicates the inextricable entanglement of society and technology with each other. With these theroretical tools, I specifically examine changes in trade routes and in the relative importance of various population centers, the use of the railroad to re-settle Muslim refugees, the roles of foreigners settling in the area, and changing patterns in agriculture as well as the “labor” of banditry. Weaving all these elements together through interconnected networks allows us to see the long-debated trope of Ottoman modernization in a more complex manner, so that it is not reduced to having a single or small number of causative agents. Instead, it is conceived of as the product of numerous factors and agents often unconsciously collaborating in the collective transform of the region.
    • The Architecture of the Deep Critical Zone: The Role of Lithology and Geologic Texture in Regolith Formation, Hydrologic Flowpath Development, and Weathering Dynamics

      Chorover, Jon D.; Moravec, Bryan; McIntosh, Jennifer C.; Rasmussen, Craig; Pelletier, Jon D.; Ferre, P.A. Ty (The University of Arizona., 2019)
      The critical zone (CZ) represents the living skin of the Earth’s surface, which extends from the bottom of freely circulating groundwater to the top of the vegetative canopy. CZ biogeochemistry includes abiotic and biotic weathering processes that occur within pores and fractures, which aggregate (or average) along the myriad of hydrologic flowpaths that make up the shallow and deep CZ. Landscapes evolve as a function of the both bottom-up controls, dependent on the initial geologic template and past weathering/geologic forcing (e.g. tectonics, sedimentary reworking, etc.), and top-down forcing driven by climate. As such, the dynamic interaction between top-down forcing and bottom-up controls is evident in the architectural framework of the CZ, exhibited by weathering profiles in the subsurface, and contemporary biogeochemical processes visible as exported solutes in surface, soil, and groundwater. Within this framework, point measurements collected along flowpaths, coupled with bulk solid sampling are traditionally used to identify weathering reactions occurring in the subsurface. Much of the foundational CZ science has been conducted in relatively simple, monolithic geologic settings, whereby spatial variability in mineral and geochemical compositions are explained by ongoing weathering front propagation and contemporary fluid/rock interactions. However, within the CZ literature, little attention has been paid to complex geologic settings, where past weathering processes may impart significant mineral and geochemical overprints not related to ongoing, contemporary CZ processes. Yet, CZ processes in these settings are dependent on past geologic processes as they alter both geologic texture (e.g. pore size and distribution) and mineral composition, especially at the fluid/surface interface, compared to fresh, unaltered protoliths. This framework provides the underpinning for the present study, where resolving weathering profiles in the complex geologic setting of the Jemez River Basin Critical Zone Observatory, located in the Valles Caldera National Preserve, northern New Mexico, required characterization of the CZ architecture as a function of both geologic legacy and contemporary CZ processes. The CZ architecture (to 50 m) in a small zero-order basin (ZOB, area approximately 16 ha) located in the JRB-CZO was characterized by an array of complementary approaches, analogous to needing as many equations as there are unknowns. In the summer of 2015, surface geophysical surveys were conducted in the ZOB, which included surface seismic and electrical resistivity surveys along two transects (one roughly north-south, the other roughly east-west). These surveys identified a slow p-wave velocity zone that extended 4 to 6 m deep that mantled the ZOB, coinciding with a highly weathered surface. Weathering decreased with depth (as shown with increasing p-wave velocities), with competent bedrock (p-wave velocities approximately 4,000 m s-1) present at a depth of approximately 50 m. Electrical resistivity profiles showed that the eastern portion of the ZOB had less water and/or clay than the western portion of the ZOB. Using these geophysical data, the depth of the weathering profile was estimated to extend to 50 m in depth. Informed by the geophysics, a drilling campaign was undertaken in the summer of 2016, excavating continuous cores down to approximately 46 m (eastern and western slopes) and 20 m (catchment convergent zone) at three locations in the ZOB, which reflected contrasting geologies and landscape positions (i.e. eastern drill location: Bandelier Tuff; western drill location: volcanic breccia; central drill location: convergent zone with mixed lithology). Core sample analysis, collected as subsamples approximately every 40 to 60 cm, revealed that the upper 15 to 18 m of the western and eastern borehole locations consisted of matrix dominated morphology, transitioning to fracture dominated morphology below ca. 15 m. The eastern borehole was composed of welded to sub-welded tuff with a mineral composition that included quartz, alkali and plagioclase feldspar, smectite, zeolites, and amorphous minerals in the upper 15 m, showing evidence of prior interaction with alkaline hydrothermal fluids. Below 15 m, the fractured welded tuff was comprised mostly of primary minerals (quartz, alkali and plagioclase feldspar, cristobalite, and volcanic glass), exhibiting relatively little weathering within the bulk. However, fracture surfaces were coated with oxidized Fe and Mn. The western borehole was composed of rounded to subrounded quartz, frayed biotite and calcite nodules in the upper 15 m, with a significant amount of illite and smectite present. At 14 m, the lithology changed to vesicular tuff, with significant zeolitization in the first 10 m coinciding with stratified ash deposits. The convergent zone was a mixture of smectite and oxidized Fe and Mn with weathering feldspar. Traditional, sigmoidal weathering front propagation was not visible in geochemical mass transfer coefficients (i.e. tau), likely as a result of incomplete weathering of rock fragments in the upper profile. However, trends in mass transfer calculations coincided with changes in mineral composition and geophysical data (e.g. magnetic susceptibility, seismic velocities, and electrical conductivity) as a function of depth. Multivariate statistical analysis of the complementary data sets, using linear discriminant analysis (LDA), identified zones within the weathering profiles, which was used to develop a conceptual framework of the deep CZ architecture and weathering profiles in the ZOB. A key finding from the deep CZ characterization study was the depth distribution and character of hydrothermally altered secondary mineral assemblages and overall secondary mineral phases in the contrasting geologies in the ZOB. It was hypothesized that these secondary mineral coatings likely played a significant role in aqueous geochemistry evolution along flowpaths due to fluid/surface interactions. Surface coatings included smectite and zeolites in the hydrothermally altered tuff on the eastern portion of the watershed down to 15 m, which transitioned to fracture surfaces coated with oxidized Fe and Mn. At all portions of the borehole at this location, larger primary mineral grains, such as alkali and plagioclase feldspars, were largely unweathered with some surface weathering occurring where smectite and zeolite precipitates on the surfaces. It was hypothesized that zeolites were precipitated as a result of glass weathering, and the smectites likely precipitated as a result of both zeolite and feldspar weathering. Enrichment of Sr and Ba, compared to Ca was observed in zeolitic zones. Enrichment of rare earth elements and Y (REY) was observed at depths where smectite content increased, indicating sorption of REY on clay surfaces. In addition, oxidized Fe and Mn on fracture surfaces appeared to shield bulk rocks from weathering. Reactions at the fluid/surface interface, whose surface composition and characteristics appear to be a result of both past and contemporary weathering processes, was hypothesized to control aqueous solution chemistry in the subsurface. Experimental weathering reactions of core materials were performed at increasing time steps, up to 1 year, to pinpoint geochemical reactions and mineral weathering rates occurring in the subsurface. Experimental weathering showed that colloidal dispersion released zeolites to solution, which were subsequently weathered to smectite. Calcite dissolution/precipitation reactions appeared to regulate solution chemistry in the volcanic breccia. Deep core samples, representing the fractured portion of the deep CZ, had experimental solution chemistry that did not match the groundwater signatures collected from deep monitoring wells in the ZOB. However, experimental solution chemistry from altered tuff samples appeared to closely match deep groundwater chemistry collected from monitoring wells, indicating deep groundwater chemistry in the ZOB derived most of its solution chemistry from reactions in the shallow CZ (e.g. <14 m) rather than at depth. The findings of this study suggest that contemporary CZ processes greatly rely on the geologic architecture and past geologic legacy in addition to climatic forcing. This is particularly true in complex volcaniclastic terrains, such as the Valles caldera. In addition, complementary analysis, including geophysics, drilling, mineralogy, geochemistry, and experimentation provide an in-depth view into spatial as well as temporal controls on deep CZ processes.
    • Exploring Parent Experiences with Early Palliative Care Practices in the Neonatal Intensive Care Unit

      Gephart, Sheila M.; Quinn, Megan; Crist, Janice; Shea, Kimberly (The University of Arizona., 2019)
      The anxiety and uncertain outcome of an admission of a seriously ill infant to the neonatal intensive care unit (NICU) can cause great stress for parents. This stress can lead to decreased quality of life and poor mental health outcomes including anxiety, depression, and posttraumatic stress disorder (PTSD), which NICU parents suffer from at higher rates than parents of well infants. Palliative care (PC) is an approach to care that aims to maintain the quality of life for a person and their loved ones by emphasizing value-based decision-making, management of distressing symptoms, and family-centered care. Early implementation of PC emphasizes shared decision-making, care planning, and support for coping with distress. Evidence from pediatric, adult, and perinatal literature supports the use of early PC, but barriers to implementation exist, and NICU PC literature focuses exclusively on end-of-life. Evidence is needed about these three early PC practices from NICU parents in order to develop a parent-centered program of early PC. The purpose of this study was to explore parent experiences with shared decision-making, care planning, and coping with distress during their child’s NICU admission. Qualitative descriptive methodology was used, and strategies of reflexive journaling, peer debriefing, and data audits were used to enhance trustworthiness. Participants were recruited online through email and social media sites of a parent organization. Sixteen individuals participated in semi-structured interviews using videoconferencing technology. Participants also completed an online survey to supply demographic information and describe relevant characteristics of their infants to contextualize the qualitative data and describe the sample. Qualitative data was analyzed with a conventional content analysis approach by coding important phrases and abstracting these to overarching themes. Parents’ descriptions of shared decision-making contained three key aspects of their experience: gathering information to make a decision, the emotional impact of the decision, and influences on their decision-making. In experiences with care planning parents described learning to advocate, having a spectator versus participant role, and experiencing care planning as communication. The key themes expressed regarding parental coping were exposure to trauma, survival mode, and a changing support network. These findings provide practicing clinicians with key areas for improvement: providing more support and collaboration in decision-making, true engagement of parents in care planning, and supporting peer support and interaction in the NICU environment. Implications for research include exploring parent experiences with early PC practices with a more ethnically and culturally diverse sample. Researchers may also further this research by developing and evaluating programs of PC emphasizing early intervention not limited to infants with a terminal diagnosis. Parents’ use of social media should be studied further due to its emerging use as a tool for peer connection and support in the NICU. Limitations of this study include a lack of diversity in sample race or ethnicity and marital status. This study provides a beginning foundation for the work of implementing early PC in the NICU from a parent-centered perspective, emphasizing communication and the building of relationships between parents and clinicians, and parents and researchers to achieve this goal.
    • Chaperone Limitations in Prion Curing

      Capaldi, Andrew P.; Ge, Xuezhen; Serio, Tricia R.; Buchan, Ross J.; Chapman, Eli; Dieckmann, Carol L. (The University of Arizona., 2019)
      Amyloid promotes a dramatic transition in protein conformation that perpetuates, giving rise to a broad variety of distinct phenotypes, ranging from pathological disorders to dynamic heritable traits. Amyloid has long been thought to be resistant to clearance by the proteostasis network, but increasing evidence is challenging this view. For example, heat shock disassembles yeast prion amyloids, revealing in vivo solubilization of these aggregates. However, the exact proteostatic niche that promotes amyloid clearance is largely unknown. We identified several environmental stresses leading to prion curing via the same mechanism as heat shock and further showed that a shared characteristic was the activation of the transcription factor heat shock factor 1 (Hsf1). Strikingly, artificial Hsf1 activation interfered with heat shock-mediated prion curing, presumably due to overexpression of a nucleotide exchange factor Sse1. Limiting Sse1, which decelerates the Hsp70 cycle, promoted chaperone loading on prion aggregates and enabled artificial Hsf1 activation to resolve prion aggregates; in contrast, it impaired resolution of stress-induced aggregates and cell growth at elevated temperature. Thus, our study demonstrates that the proteostasis network, fine-tuned for optimal dissolution of non-amyloid aggregates, can be reconfigured for solubilization of amyloid by modulating the Hsp70 cycle.
    • Portfolio of Works

      Asia, Daniel; Bramble, Zachary James; He, Kay; Decker, Pamela (The University of Arizona., 2019)
      A composer can never fully understand the breadth and importance of his weight in modern musical tradition. The inspiration for works listed in the compilation that follows is one questions I have pondered since I began my vocation as a composer. The primary focus of this compilation is to display competency in the written language of my music, and to illustrate a traditional musical focus in which my styles are based. The compositional approach of my work is to establish a modernized use of traditional music practices to further develop the posterity of the musical repertoire, and is also to display my perspective on modernity and how it relates to past traditional music writing practices. The inspiration for this compilation is music, largely for the sake music itself. If one claims they are a composer, they must provide a wide portfolio of written work, notwithstanding stylistic diversity within their catalogue. These works are a cumulative display of my work as a composer, and thus within this selected grouping, there is no shortage of humor, seriousness, schmaltzy phrasing, modernized language, and overall artistic expression based on my view and understanding of the Western classical music culture. One of my primary inspirations in all of music history is Beethoven and his use of motives, which I try to rely on in my musical language. Though I also try to develop my own unique voice as an artist, I believe that there is always room for a broadening of one’s own perspective as it relates to that of another artist’s perspective late, or still living. Though my influences and tastes in listening do surely influence what I write, I try to prepare interesting new styles for the prospective listener. This compilation is indented to demonstrate, my voice, my stylistic perspectives, and my musical opinions. As artists, we make statements with our expressiveness. We challenge normative thought processes, and have an obligation to progressivism with a grounding in what our musical founders Monteverdi, Bach, Mozart, Beethoven, Brahms, and Schoenberg - my favorite composers - have set into motion. This compilation is one of many in the vast sea of my artistic musical expression, and I hope it sparks interest, and inquiry, for any of those curious minds looking for something new in music infused with a hint of historical artistic tradition.
    • A Family Systems Approach to Sleep Patterns in Down Syndrome

      Edgin, Jamie O.; Romero, Andrea J.; Khosla, Payal; Taylor, Angela R. (The University of Arizona., 2019)
      Down syndrome (DS) is one of the most common genetic conditions that manifests in a physical, behavioral, mental, emotional, and neurocognitive manner (Bittles, Bower, Hussain, & Glasson, 2006; Bull & the Committee on Genetics, 2011). In terms of physical health, individuals with DS are at a higher risk for congenital heart defects, hypothyroidism, gastrointestinal issues, and sleep problems (Bittles et al., 2006; Carter, McCaughey, Annaz, & Hill, 2009). Of particular importance, is the 30% to 80% prevalence rate of obstructive sleep apnea syndrome (OSAS) in DS (Dyken et al., 2003; Shott et al., 2006). OSAS as well as other sleep disturbances have been linked to neurocognitive and developmental delays among individuals with DS (Breslin et al., 2014; Edgin et al., 2015). A limitation to previous work in DS is evaluating sleep and its impact on development from a family systems perspective. The family’s interconnectedness, cohesiveness, and self-stability characteristics may play a role in sleep and development for individuals with intellectual disability. The three studies presented in this dissertation examined the multiple ways in which sleep effects all members of the family in addition to infant development in a longitudinal sample of infants with and without DS from 6-months to 24-months of age. In Study 1, we investigated work schedules among parents of 18-month-old infants with DS and typically developing (TD) along with its impact on infant sleep quality and quantity. There were no significant differences in work schedules and total number of hours worked per week between parents in both groups. However, infants with DS displayed significantly less sleep time, greater fragmentation index, poorer sleep efficiency, and more time waking up after sleep onset (WASO). We found group differences in nights per week spent co-sleeping and parents’ perceptions regarding the importance of a consistent bedtime routine. When assessing employment schedules, regardless of group, parents who were unemployed were more likely to indicate having an exact bedtime routine for their infant followed by parents with standard and nonstandard work schedules. Parenting stress was significantly higher among parents with a standard work schedule followed by parents with a nonstandard work schedule and unemployed. Finally, we found infant WASO to be highest in the nonstandard work schedule group and unemployed for families with and without DS, respectively. These results highlight the importance of assessing parental work schedules to better understand infant sleep patterns and family functioning. The findings from Study 1 indicate that sleep deficits begin to emerge as early as 18-months among infants with DS. In Study 2, we investigated a specific sleep practice - co-sleeping - and its association with sleep efficiency and daytime regulation among infants with and without DS at 18-months-old. Results indicated that while co-sleeping all of the night is more common among TD infants (approximately 26%), the most common type of co-sleeping for infants with DS was the second part of the night (almost 18%). Infants with DS not only displayed significantly poorer sleep efficiency but also higher scores on the depression/withdrawal subscale of the Infant-Toddler Social and Emotional Assessment (ITSEA) and lower adaptive behavior scores, both signifying delays in socio-emotional outcomes. Co-sleeping frequency was not correlated to sleep efficiency and any of the daytime regulation variables. Nonetheless, these findings suggest a need to assess co-sleeping behaviors in further detail and determine its impact on other sleep parameters and developmental outcomes in children at risk for sleep problems. In the first study, one of the prominent findings involved differing sleep practices between groups, specifically co-sleeping behavior and parents’ perceptions surrounding a bedtime routine. The second study addressed co-sleeping patterns and daytime regulation; therefore, in Study 3 we evaluated the associations between bedtime routine consistency, daytime functioning, and overall sleep quality, relationships not previously studied in this population from 6- to 24-months of age. Findings indicated that parents engaged in a consistent bedtime routine with their infant and their perception of the importance of the routine on their infant’s development increased with time. Growth curve models showed that a consistent bedtime routine was related to less externalizing behavior and fewer vocalizations particularly in the TD group and a 10-point difference in adaptive behavior scores with each assessed time point and longer sleep times regardless of group. Significant group differences were found such that infants with DS displayed less internalizing behavior and poor sleep efficiency compared to TD infants. The results highlight the impact of a consistent bedtime routine for all children, typical and atypical. Altogether, the three papers provide insight into sleep practices that, to our knowledge, have not been studied in the DS population. We note how parent-level factors such as works schedules, decision to co-sleep, and implementing a consistent bedtime routine impact infant sleep behavior. The last study proposes a strength-based approach not deficit-based approach to studying atypical development. Future work should further investigate different factors influencing infant sleep and development while also considering parental sleep behavior to obtain a holistic assessment of sleep among families with DS.
    • Exposures and Health Risks of the Diné Communities Impacted by the Gold King Mine Spill

      Beamer, Paloma I.; Van Horne, Yoshira Ornelas; Chief, Karletta; Canales, Robert A.; Bell, Melanie L.; Klimecki, Walter T. (The University of Arizona., 2019)
      On August 5th, 2015, an abandoned gold mine near Silverton, CO was accidentally disturbed, resulting in 3 million gallons of acid mine drainage containing arsenic and lead being released from the Gold King Mine, eventually reaching the San Juan River. The Diné (Navajo) people have a deep spiritual connection to the natural environment and rely heavily on the San Juan River for agricultural, spiritual and cultural practices. The initial risk assessment conducted by the U.S. EPA only considered a recreational scenario (i.e., a hiker drinking from the river) and concluded that there would be no adverse effects from exposure. This U.S. EPA risk assessment did not take into account the cultural, residential or dietary pathways of the Diné. While the environmental impacts of the Gold King Mine Spill (GKMS) have been investigated by various governmental agencies, the Diné-specific impacts as a result of the GKMS are unknown. Understanding the community-specific impacts of the GKMS is necessary to develop effective recovery programs. Through the Gold King Mine Spill Diné Exposure project, twelve focus groups were held on the Navajo Nation to identify interactions between the Diné and the San Jun River. A total of 43 unique activities were identified and grouped into one of five distinct categories: livelihood, recreational, cultural and spiritual, dietary, and arts and crafts activities. Within one year of the GKMS, Navajo Nation Community Health Representatives administered the questionnaire to adults living on the Navajo Nation in communities along the San Juan River. A total of 63 adults and 27 children were recruited for participation in this study. On average there was a 56.2% decrease in the number of activities that participants engaged in with the San Juan River following the GKMS. The GKMS was a traumatic event for the Diné, which may lead to long-term mental health effects. Additionally, the significant reduction in all activity categories following the GKMS indicates that Diné adults may refrain from passing down their teachings, which may negatively impact future generations to come. We conducted a community-based probabilistic risk assessment from exposure to arsenic and lead at three different time points (i.e., pre-, peak-, and post-GKMS) for three exposure pathways: 1) recreational, 2) cultural, and 3) dietary, that were potentially impacted by the GKMS. These three pathways are referred to here as “San Juan River pathways” (i.e., certain recreational, cultural, and dietary pathways). Utilizing the Lifeline Community Based Assessment Software (CBAS), we incorporated distributions for different exposure factors (e.g., hand-to-mouth contacts, transfer efficiency) along with Diné-specific activities (e.g., putting Chii (red earth found near rivers) on face for prayers) to simulate a dose estimate. The estimated hazard quotients (HQs) from the arsenic and lead dose estimates were less than one for all time points and for the three exposure pathways potentially impacted by the GKMS (i.e., San Juan River recreational, San Juan River cultural, and San Juan River dietary pathways), indicating no excess non-cancer risk. In addition to the pathways potentially impacted by the GKMS, we integrated exposure pathways that were thought not to be impacted by the GKMS referred to here as “non-San Juan River pathways” (i.e., certain recreational, cultural, dietary, and residential pathways) to estimate the potential aggregate non-cancer and cancer risk from exposure to arsenic and lead. The dietary pathway unaffected by the GKMS (i.e., consumption of food and water) was the main contributor to arsenic and lead. For arsenic, approximately 58% of the scenarios exceeded an HQ of one via the non-San Juan River dietary pathway, and 85% were above the 1 x 10-04 acceptable cancer risk guideline. The added dose from exposure through pathways impacted by the GKMS was relatively low and does not significantly contribute to overall non-cancer or cancer risk estimates. As dose estimates vary by orders of magnitude between the recreational, cultural, and dietary pathways, it is still important to consider them in the risk assessment process. To ensure community concerns stemming from the Gold King Mine Spill disaster are addressed, continued dissemination of results in a culturally-appropriate manner, collaboration with governmental agencies, and community partnerships are key. This risk assessment provides the first documentation of incorporating unique exposure pathways of the Diné people and raises the need to incorporate community-specific pathways during the risk analysis process.
    • Best Practices for Microalgae Cultivation by Capturing Carbon and Dissemination of Energy-Water-Food Concepts to Multiple Audience and Exploring Inclusivity in Higher Education in the Southwest Region

      Ogden, Kimberly L.; Acedo, Margarita; Saez, Avelino E.; Guzman, Roberto; Slack, Donald (The University of Arizona., 2019)
      This dissertation contains results of the research I have done in two areas I am interested in: energy and education. The energy-based research focuses on renewable energy as well as carbon capture and utilization. The educational research includes K-12, outreach, and higher education programs. Combining energy and education has allowed me to apply engineering concepts to education and disseminate energy concepts to a wide audience, including K-12 students, Navajo Nation members, and higher education colleagues. I demonstrated best practices for microalgae cultivation when combining carbon capture with renewable energy generation, thus making it possible to reduce the carbon footprint of power plants, knowledge that I shared with the communities noted above. In addition, as a graduate student, I have utilized my research skills to conduct research in higher education by exploring inclusive environments in graduate programs in the College of Engineering, which is part of my dissertation. This research allowed me to develop instruments and protocols to assess equity and the learning climate in graduate programs within the College of Engineering. Recently, the energy field has been driven to develop new technologies that minimizes greenhouse gas emissions, mainly CO2, for the purpose of mitigating global warming. This drive has advanced microalgae-based CO2 sequestration research because of microalgae’s photosynthetic capacity to fix CO2. Microalgae are a promising source of biomass and suitable candidates for biofuel production. Thus, this project explored the potential synergy of microalgae cultivation and carbon capture in both the laboratory and at pilot scale at two generation stations: The University of Arizona (UA) and Tucson Electric Power. Previous laboratory experiments demonstrated that algae can tolerate flue gas compounds. The pilot-scale experiments assessed the potential of state-of the- art technology for algal biofuel and carbon capture utilization in two different power plant scenarios, including one with extremely high temperature conditions due to the reactor’s location close to the boiler. The results of microalgae growth utilizing flue gas showed microalgae yields as high as 0.29 g/L ash free dry weight (AFDW) and a lipid content of 24%. Leveraging observed synergic opportunities between CO2 emitters and algal farmers can provide resources required to increase carbon capture while enhancing a sustainable production of algal biofuels and bioproducts. The energy field has been attempting to diversify the nation’s energy portfolio not only by introducing innovative technology but also by providing energy security. Another dissertation chapter explores the fossil energy transition plan for the Navajo Nation. Potential alternative energy resources, including solar photovoltaics and biomass (microalgae for either biofuel or food consumption), were assessed. The methodology for this analysis consisted of data collection from publicly available data, utilizing expertise from national laboratories and academics, and evaluating economic, health, and environmental impacts. The results of this study highlighted areas of opportunity to implement renewable energy within the Navajo Nation by presenting the technology requirements, costs, and considerations regarding energy, water, and the environment within an educational structure. Another chapter focuses on K-12 energy curriculum. Students conducted an electrolysis experiment, using the scientific method, to separate microalgae from water as a hands-on introduction to water treatment processes. From this experience, students learned how electrolysis works and became familiar with several real-world applications. Over the years, diversity has increased at the UA, and currently, the institution is looking to maintain this trend. However, literature has shown that even within equitable learning environments, conflict, tension, and microaggressions may emerge; an increase in diversity does not equate to an increase in inclusivity. This finding led me to design a collaborative project with the Office of Instruction and Assessment (OIA) that explores the current climate in the College of Engineering at UA through survey instruments and classroom observation protocols that assess inclusive environments in graduate programs. In summary, this dissertation enabled me to integrate energy and education research. I coupled carbon capture and microalgae cultivation; I applied and disseminated energy concepts to K-12 students, the Navajo Nation community, and higher education; and I employed my research skills to study and develop instruments to assess learning environments in higher education.
    • The Costs of Adaptation: A Comparative Study of Marine Protected Area Planning and Small-Scale Coastal Communities in Eastern Indonesia

      Vásquez-León, Marcela; Durney, Florence; Sheridan, Thomas; Lansing, J. Stephen; Fisher, Larry (The University of Arizona., 2019)
      The 21st century has been characterized by unprecedented anthropogenic marine environmental change, and by an increasing understanding that such change will only accelerate in future. The movement of concern from academic to political and public discourse and practice has changed both the context and matrix of stakeholders from researchers, government officials, and marine resource managers, to include NGOs, citizens, and activist groups. Indonesia represents an acute challenge in relation to future marine resource management. An archipelagic nation of 17,500 islands, it is the fourth most populous nation in the world, and hugely dependent on marine resources for subsistence and livelihood. Sitting at the center of the Coral Triangle, it also hosts the highest levels of marine biodiversity yet recorded. Balancing the rights of Indonesia’s dependent coastal populations with the mandate to protect its increasingly stressed marine environment is an unending and complex governance issue. This dissertation examines how this balance is being struck in relation to one tool of marine resource management: marine protected areas (MPAs). Through an ethnographic comparison of two neighboring MPA projects in Nusa Tenggara Timor (NTT) province in Indonesia, I document how the planning and implementation of protected areas is impacting small-scale and traditional coastal communities in a context of social and economic change. In doing so this dissertation forwards multiple research agendas. First, it documents the rich cultural practices surrounding marine resource use in NTT, a comparatively undeveloped region that remains closely tied to marine ecosystems. Second, it contributes to the analysis of how external ways of seeing and managing the marine environment impact traditional resource users. Drawing on theorizations of discourse and gaze, it pays particular attention to the narratives and imagery that managers, conservation actors, and local peoples use in their struggles over access to and control of resources. Lastly, this dissertation seeks to contribute to better MPA policy-making in Indonesia, and globally, by documenting challenges and re-examining current best practices of MPA management in a region of intensive MPA implementation.
    • Optical System Design and Distortion Control of Wide Field of View, All-Reflective Imagers

      Sasian, Jose; Johnson, Timothy; Schwiegerling, James T.; Liang, Rongguang (The University of Arizona., 2019)
      Wide field of view (FOV) optical systems allow imaging of large scenes for panoramic photos, surveillance and reconnaissance, or survey missions such as monitoring changes of the earth surface related to global warming. Many current wide field of view systems allow significant optical distortion simplifying the optical design while also allowing compatibility with small, current-technology focal plane arrays. These optical systems are typically refractive, like a fish-eye lens, which has certain downsides such as: limited spectral range, higher absorption, and increased thermal sensitivity. It is also common for wide FOV systems to sacrifice spatial resolution and signal to noise ratio (SNR) in order to maintain a compact system size. The aperture-FOV product, known as throughput, is generally difficult to increase beyond current practice, thus increasing the FOV often comes at the expense of aperture size. This dissertation explores new all-reflective optical designs, system configurations, and applications for wide FOV, high throughput systems with near zero or positive beneficial distortion. These all-reflective, off-axis, unobscured designs utilize freeform mirrors, which allow additional freedom in optical surface form required for precise distortion control over a wide field. Even an optical system with no internal distortion produces distorted images of the earth due to its convex curvatures. The optical system can be designed with positive distortion to counter the negative distortion of the curved-earth to produce images with constant resolution. Four new optical designs are given in this dissertation that are novel because they are all-reflective and have and extreme combination of wide FOV and zero to positive image distortion. These 4 designs have the following f/#, EFL, FOV, and distortion: 1) f/3, 2.6 inch EFL, 120° x 4° FOV, 0% distortion, 2) f/2.5, 2.5 inch EFL, 70° x 4° FOV, +13% distortion, 3) f/2.5, 2.2 inch EFL, 90° x 12° FOV, 0% distortion, and 4) f/2.5, 2.2 inch EFL, 60° x 20° FOV, 0% distortion. These designs are ideal for mid-wave and long-wave infrared systems, not only because they are all-reflective, but they also feature an exit pupil for a cold stop to reduce thermal background signal. Optical design software reports Zernike polynomial aberrations vs field, but the polynomial is contaminated by higher order aberration terms inherent in wide FOV designs. A method is shown to convert Zernike polynomials to monomial aberrations which provide a more direct understanding of the design’s aberration behavior. This process is essential to measure aberration nodes, relating to Nodal Aberration Theory, for wide FOV systems. Distortion in bilaterally symmetric optical systems (off-axis reflective designs) such as smile, keystone, and anamorphism are calculated per surface and their wavefront field maps are analyzed. An in-depth study of all possible 3-mirror design configurations is given highlighting new design possibilities. Scanning optical systems, such as push-broom and whisk-broom satellite sensors are compared using a satellite sensor system model that includes orbital mechanics. It is shown that a wide FOV, small entrance pupil, mechanically simpler push-broom system, can have better performance than current-practice narrow FOV, moderate aperture, whisk-broom sensors. The optical designs in this dissertation have large AΩ product (throughput) requiring large or multiple FPAs. The FPAs needed for these designs are not readily available with today’s technology. These designs also require large freeform mirrors that may be challenging for fabrication and alignment. However it is not the goal of this dissertation to balance optical design with practical or economical FPA, mirror fabrication, and alignment. Instead the goal is to present a series of progressive optical systems that can be made possible with cutting edge FPA and mirror fabrication technology. It is hoped that the optical designs described in this dissertation can be used in a future satellite sensor or other application benefiting from an all-reflective, wide FOV system with zero or positive image distortion.
    • Fighting Men, Enduring Women: Sailors and Their Families in the United Kingdom, 1770-1820

      Tabili, Laura; Zepeda, Sofia; Crane, Susan A.; Lotz-Heumann, Ute (The University of Arizona., 2019)
      This dissertation examines the everyday lives of sailors and their wives in the United Kingdom from 1770 to 1820, establishing the cost of living for women left behind, revising the chronology of the breadwinner wage, and revealing their relationship to their community, charitable organizations, culture, and the state. It brings together a unique combination of sources including parish records, newspapers, Admiralty records, court records, and prints and songs to locate these families who often left few records of their own. By showing the quotidian economic and social realities these families faced, this dissertation reveals not just the importance of the families themselves in propping up valued imperial structures, but how they managed to survive it all. The state and community leaders often viewed sailors and their families as both worthy of and in need of support, a group in need of protection and supervision. By analyzing those relationships, this project shows the negotiated relationships of patriarchy and welfare between sailors, their wives, and charitable and state organizations. It also shows how cultural materials aimed at different audiences portrayed or ignored their quotidian circumstances. Furthermore, by examining the lives of sailors and their wives in port towns in England, Wales, Scotland, and Ireland, this research departs from existing scholarship and better establishes continuities between regions and important differences in their everyday lives.
    • Phytoliths and Microcharcoal from East African Lake Sediments Used to Reconstruct Plio-Pleistocene Vegetation and Hydroclimate

      Cohen, Andrew S.; Yost, Chad Lambert; Archer, Steven R.; Quade, Jay; Holliday, Vance T.; Barboni, Doris (The University of Arizona., 2019)
      Global climate is changing at a rate that is unprecedented for the modern era, and atmospheric CO2 is at a level that has not been seen in ~3 million years. Recorded climate observations extend back only ~130 years. In order to understand how the Earth system may respond to present and future levels of CO2 forcing, we need to interpret ancient archives of climate and vegetation. The study of human evolution also involves studying past climate and vegetation, as it may have been influenced by climate change. Reconstructing past climate and vegetation often requires the use of robust molecular and microscopic fragments of plants. This dissertation uses microscopic plant opal silica phytoliths and microscopic charcoal from East Africa to reconstruct vegetation and hydroclimate for three important places and times in Earth and human history: (i) the Lake Malawi region after the Mount Toba supereruption at ~74 ka, (ii) the mid-Piacenzian Warm Period (MPWP) and the Plio-Pleistocene transition (3.29–2.57 Ma) in the Baringo Basin, Kenya, and (iii) the early Pleistocene (1.87–1.38 Ma) in the Turkana Basin, Kenya. These three study sites were investigated by drilling ancient lake sediments to recover soft sediment cores. From these cores, a total of 1029 samples were analyzed for phytoliths and microcharcoal. For the Mount Toba supereruption, we found no change in low elevation tree cover, or change in cool climate C3 and warm season C4 xerophytic and mesophytic grass abundance that was outside of normal variability for samples synchronous or proximal to the eruption. A spike in locally derived macrocharcoal and xerophytic C4 grasses immediately after the Toba supereruption indicated reduced precipitation and die-off of at least some afromontane vegetation, but did not signal volcanic winter conditions as had been hypothesized. For the Baringo Basin during the MPWP (3.26–3.01 Ma), which is the last time global atmospheric CO2 in a warm world was at levels similar to today, intervals with exceptionally high microcharcoal influx suggest regional turnover from woody to open habitats was driven in part by fire. After ~3.0 Ma, low elevation woody cover likely never exceeded 40% and mesic tall-grass vs. xeric short-grass savanna varied at precessional periodicities. For the Turkana Basin during the early Pleistocene, spectral analysis found that microcharcoal varied at precession (23–19 kyr), half-precession (9.6 kyr), and quarter-precession (5.1 kyr) periodicities, and linked orbital-forced peaks in precipitation with elevated fire on the landscape. Phytoliths show that C4 mesic and C4 xeric grasses varied at precession and quarter-precession periodicity. Identification of the Natoo Tuff in WTK13 allowed a direct linkage to the Nariokotome Boy Homo erectus/ergaster site. At the time that the Nariokotome Boy walked this ancient landscape, phytoliths indicate that the area was a seasonally wet and open environment dominated by short stature C4 Chloridoideae grasses, sedges, and other herbaceous plants.
    • Risk Factors for Pressure Ulcer Development in Non-Critical Aeromedical Evacuation Trauma Patients

      Brewer, Barbara; Mortimer, Darcy Lee; Gephart, Sheila; Carrington, Jane (The University of Arizona., 2020)
      Background: The military in-flight care environment is unique. Non-critical Aeromedical Evacuation (AE) trauma patients are at risk for developing pressure ulcers (PUs) in-flight. This study examines the incidence of in-flight PU development and analyzes factors that may contribute to them. Methods: This study employed a retrospective case-control cohort analysis of electronic data from January 1, 2008 through December 31, 2012 comparing non-critical AE trauma patients who did and did not develop PUs within three days post-flight. The Department of Defense Trauma Registry identified 15 PU patients. Using the Aeromedical Evacuation Registry (AER), PU patients were matched four-to-one with non-PU patients (n=60) that had been flown within plus or minus one year of the event to control for changes in practice over time. Independent variables examined included demographics, diagnoses, care requirements, flight information, and the number of AE crew. Results: The mean age for the PU patients was 26.20 (SD=8.10); non-PU patients 26.98 (SD=8.16), with a range of 15-54 years old. Age was not significantly different (t(73) = .740, p > .05) between the PU and non-PU patients. All of the PU patients were male (n=15, 100%) and 96% (n=57) of the non-PU patients were male. Fisher’s exact test was conducted for a between group comparison, which was not significant (p = 1.00). The PU incidence rate was calculated as .02 (<1%) based on 73,377 patients discharged during the time period. A binomial Firth conditional logistic regression was performed in the face of PUs as a rare event (n=15; incidence rate <1%). The regression showed statistical significance in two of the 12 variables used in the model, namely the use of intravenous (IV) therapy (p = .04) and pulse oximetry (p = .01). Conclusion: As PUs are a Nurse Sensitive Quality Indicator, a PU incidence rate of <1% illustrates the outstanding quality of care that is being conducted in the U.S. Air Force Aeromedical Evacuation System. Identification of the risk factors that lead to PUs can help mitigate future PU development on the quest to zero PUs.
    • Knowledge Deficits of Caffeine amongst Adolescents in Metropolitan Phoenix

      Prettyman, Allen; Mandile, Amy Michelle; Davis, Mary P.; Williams, Deborah K. (The University of Arizona., 2020)
      Caffeine is a central nervous system stimulant found in natural and artificial products such as cocoa, tea, coffee, as well as energy drinks, energy shots, and additives with variable concentration levels consumed by roughly 73% of adolescents in the United States. Caffeine has several documented side effects such as increased alertness, improved focus, decreased fatigue, improved physical performance, insomnia, headache, anxiety, dehydration, abnormal heart rhythm, restlessness, physiological dependence, and death. Not much is known on what local Arizona adolescents comprehend on caffeine, its anticipated side effects, and caffeine-containing product identification. This DNP project’s primary purpose was to evaluate knowledge adolescents; aged 13-18 years have concerning common caffeine-containing beverage products. A pre-questionnaire (Appendix F), followed by an education session (Appendix G), and post-questionnaire (Appendix H) at a local Phoenix, Arizona healthcare clinic were utilized and evaluated. Results yielded a high percentage of adolescent awareness to purposeful caffeine consumption for the result of heightened alertness. Adolescents also displayed knowledge of common products such as coffee, energy drinks, and soda products to contain caffeine. There was a knowledge gap related to hydration products containing caffeine and misidentification on chocolate-flavored drinks to be without caffeine; however, this percentage decreased post-education information session, displaying that education on products is beneficial to heighten adolescent consumer awareness.