Now showing items 8330-8349 of 19787

    • HAANE’ BITS'Ą́Ą́DÉÉ’: The Process of Diné Education

      Fox, Mary Jo Tippeconnic; Begay, Waylon Nakai; Shirley, Valerie; Zepeda, Ofelia (The University of Arizona., 2020)
      This critical Indigenous qualitative study seeks to examine Diné (Navajo) students’ struggle with success in American mainstream postsecondary institutions. The aim of this research is to explore Diné graduate college student narratives about mainstream higher education and their overall purpose for attending graduate school. The heart of this research is driven by the question: What is the main purpose Diné college students attend mainstream postsecondary institutions in the United States? Two additional questions served as guides: 1.) In what ways is Diné identity & culture important at mainstream postsecondary institutions? 2.) How can mainstream postsecondary institutions incorporate more culturally based frameworks to promote American Indian student success? This study uses the unique framework of Sa’ąh Naagháí Bik’eh Hózhóón (SNBH) philosophy of balance and harmony with the Ałchi Silah (Duality) paradigm identified in Diné Philosophy to examine the overall experiences of Diné college students. In addition, this study draws upon the theoretical framework of Tribal Critical Race Theory (TribalCrit) to map out the depth and scope colonialism and neocolonialism imposes on the experiences of Diné college students in the educational environment of policies and practices, theories(stories) and school traditions of mainstream postsecondary institutions. The specific connection to student success for Diné college students is the deconstruction and reconstruction of the Diné identity in relation to the cultural landscape of U.S. mainstream universities and colleges. A narrative based inquiry (storytelling) approach is utilized to uncover successes, obstacles, and misunderstood factors of mainstream higher education in the U.S. for Diné college students. This study proposes and recommends a Diné centered epistemology to reclaim Diné identity from the hold of 21st century colonialism. A Diné centered epistemology provides within mainstream postsecondary institutions, a space where Diné identity and Diné Philosophy can flourish and benefit Diné people and surrounding communities. A space where a Diné definition of success and education can be envisioned, shared, and honored. The findings of the study emphasize that funding and academic support is needed for not just Navajo college students, but all Indigenous students. In addition, the findings illustrate a real need for an Indigenous designed space within mainstream postsecondary institutions. A site where Natives could have prayer ceremonies and collaborate alongside Native healers and leaders to create curriculum that highlights Indigenous languages and cultures. A place that houses strategic academic guidance from well-informed Indigenous teachers and leaders who work closely with Native Nation (re)Building concepts. A site that resolves inter-tribal conflicts and lets Indigenous peace and unity emerge.
    • DE HAAS - VAN ALPHEN EFFECT IN QUENCHED PLATINUM CRYSTALS.

      Vuillemin, Joseph; BOUFELFEL, ALI. (The University of Arizona., 1987)
      The oscillatory de Haas-van Alphen (DHVA) magnetization has been studied in Pt crystals containing more than 100 ppm vacancies. Magnetic fields as high as 75 kG were used. The oscillations were observed at temperatures as low as 0.45 k, and found to be strongly attenuated by the vacancies in this concentration range. The emphasis of this work is on the measurement of this attenuation for the purpose of studying conduction electron scattering due to single vacancies. Dingle (scattering) temperatures due to vacancies are reported for four cyclotron orbits with the field in a (110) plane, along with a new measurement of the cyclotron effective mass (m* = 2.31 ± 0.03) for the electron orbit 33° away from <100>. Vacancies were generated by quenching Pt single crystals from temperatures as high as 1730 °C in air, using a technique which minimizes the induced strain. The vacancy contribution to the electron scattering rate was separated by measuring the Dingle temperature in both quenched and annealed specimens which had been subjected to the same quenching process. The results suggest that there is only a moderate variation in this scattering rate over the s-p-like electron sheet of the Fermi surface. However, the scattering rate for the d-like open hole sheet, which contacts the Brillouin zone, is about 49% larger than that for the electron sheet. This anisotropy is attributed mainly to the lattice distortion around a vacancy and to the difference between the hole and electron wave-function symmetries.
    • Habitat Fragmentation in Small Vertebrates from the Sonoran Desert in Baja California

      Culver, Melanie; Munguia-Vega, Adrian; Rodriguez-Estrella, Ricardo; Nachman, Michael W.; Shaw, William W.; Culver, Melanie (The University of Arizona., 2011)
      Land conversion is one of the greatest threats to terrestrial ecosystems around the world, and understanding its impacts on the biota is crutial for the management and conservation of species in and around human-modified landscapes, particularly in those where local declines can quickly translate into the extinction of endemic species or Evolutionary Significant Units.I investigated how habitat loss and fragmentation impacted dispersal and extinction risk in three small vertebrates (a phrynosomatid lizard Urosaurus nigricaudus, and two heteromyid rodents Chaetodipus arenarius and Dipodomys simulans), in a highly fragmented agricultural valley from the Sonoran Desert in the Baja California Peninsula, Mexico, where reptiles and rodents show high endemism and phylogenetic diversity. After reconstructing the history of habitat loss at the valley during the last 60 years, my approach involved the development and genotyping of 10 DNA microsatellite loci in 800 individuals from the three species that were sampled from continuous and fragmented habitat and analyzed using various population genetic methods.Although genetic diversity was not significantly affected by habitat loss and fragmentation, I observed an increase in genetic structure, relatedness, the spatial scale of individual movement and reversal of sex-biased dispersal in the three species, compared to continous habitat. I found evidence of a large and spatially localized extinction debt in the lizard, that showed individual dispersal restricted to<400 m in the fragmented habitat, while the two heteromyids seemed capable of dispersing over distances of few kilometers. Several observations supported a higher extinction risk in kangaroo rats compared to pocket mice. Continuous areas surrounding the fragmented landscape where identified as important sources of individuals to habitat fragments located nearby. Even the vegetation associated with a narrow wash across the fragmented landscape appeared to act as a corridor as high levels of dispersing individuals were inferred in the three species over a scale of several kilometers. This study provided an approach to evaluate the effects of distinct landscape features in preventing or allowing individual dispersal in multiple co-distributed species towards their conservation in human-modified landscapes.
    • Habitat selection by the elegant trogon (Trogon elegans) at multiple scales.

      Hall, Linnea Suzanne.; Mannan, R. William; Matter, William J.; Schwalbe, Cecil R.; Calder, William A.; Block, William M. (The University of Arizona., 1996)
      In this dissertation I discuss several facets of the ecology of the elegant trogon (Trogon elegans). In Chapter 1, I assessed habitat selection by the trogon from 1993 to 1995 at three spatial scales (those of the mountain and canyon, home range, and microsite scales). At the broadest (inter-mountain and inter-canyon) scale, trogons were positively associated with cover by sycamore, pinyon, and juniper vegetation, and the abundances of three bird species. At the intermediate scale, radio-tagged trogons in the Huachuca and Santa Rita mountains used both upland and riparian areas, and selectively used sites with dense vegetation within those areas. At the microsite scale, nest sites of trogons were primarily located in sycamore trees in riparian areas. Successful nests could be discriminated from unsuccessful nests on the basis of three variables. Adult trogons used trees that were mostly dead for several behaviors besides nesting, and males foraged from sycamore and oak trees. Across all three scales, trogons were associated with variables describing sycamores, junipers, pines, and oaks, indicating that these trees were important to elegant trogon habitat use in Arizona. In Chapter 2, I discussed the behavior and phenology of nesting elegant trogons in the Chiricahua, Huachuca, and Santa Rita mountains in 1993-1994. I described the average durations and characteristics of nest advertisement, incubation, brooding, nestling attendance, and fledgling attendance behaviors. Elegant trogons in Arizona had different behaviors from other members of Neotropical Trogonidae, especially in regards to their durations of incubation and feeding. In Chapter 3, I present analyses of disturbance records collected while observing trogons in 1993-1995, and the finding that elegant trogons did not react strongly to most contacts with humans. However, on some occasions trogons reacted long enough to humans to potentially impact their productivity at nest sites. Therefore, some protection of nesting trogons may be warranted. In general, management of trogons in Arizona will require consideration of whole watersheds, including the condition of riparian water tables and upland vegetation.
    • Habitat-Defining Genes and Synteny of Conditionally Dispensable (CD) Chromosomes in the Fungus Nectria Haematococca

      VanEtten, Hans D.; Rodriguez, Marianela; VanEtten, Hans D.; VanEtten, Hans D.; Hawes, Martha C.; Orbach, Marc J.; Dieckmann, Carol L.; Goll, Darrel E. (The University of Arizona., 2006)
      Individual isolates of the fungus Nectria haematococca exist in a wide range of habitats and part of this diversity is attributed to the presence of conditionally dispensable (CD) chromosomes that carry habitat-defining genes. In the current study a new factor located on one of these CD chromosomes was found. This trait allows pea pathogenic isolates of N. haematococca to grow in homoserine, a compound present in large amounts on pea root exudates. The gene(s) for homoserine utilization (HUT) are located on the same CD chromosome that carries the cluster of genes for pea pathogenicity, the PEP cluster. The PDA1 gene, a member of the PEP cluster, is routinely used as a marker for the presence of this CD chromosome, therefore it has been called the PDA1-CD chromosome. For the purpose of identifying the HUT gene(s), a physical map of the PDA1-CD chromosome was constructed. This map, in combination with synteny analysis, and Southern hybridizations led to the identification of a region of 365Kb that is likely to contain the HUT gene. By searching the publicly available genome of N. haematococca several candidates for HUT were identified.The synteny evaluation between the PDA1-CD chromosome and a different CD chromosome that carries the MAK1 gene, for chickpea pathogenicity, revealed a region (> 463Kb) of synteny, which advocates for a common ancestor for these CD chromosomes. However a large region (~ 1 Mb) in each of the CD chromosomes was found to carry unique DNA, therefore we proposed that individual isolates of this fungus contain large regions of unique DNA located on the CD chromosomes. The localization of syntenic regions also suggests that breakage points previous identified in the MAK1-CD chromosome could potentially be "hot spots" for recombination between both CD chromosomes. Furthermore, the anchoring of the PDA1-CD map to the genome of N. haematococca allowed the identification of additional putative habitat colonization genes present on both CD chromosomes, and niche-defining genes on the PDA1-CD chromosome.
    • Haboobs in outer space: the when and where of dust storms in distant galaxies

      Dickinson, Mark E.; Jannuzi, Buell T.; Pope, Alexandra; Penner, Kyle; Dickinson, Mark E.; Jannuzi, Buell T.; Pope, Alexandra; Zaritsky, Dennis; Fan, Xiaohui (The University of Arizona., 2014)
      Dust grains are a minor component by mass of the interstellar medium of a galaxy. Yet they can be the dominant source of luminosity. At z ∼ 1, the luminosity density of the Universe in the IR is ∼ 10 times higher than it is at z ∼ 0; common high-redshift galaxies have IR luminosities and dust masses that surpass those of even rare low-redshift galaxies. Dusty galaxies must transition to dust-poor galaxies. In this thesis, we attempt to understand the When? and Where? of this transition. We examine the redshift distribution of the cosmic millimeter background and the spatial distributions of dust in high-redshift galaxies. The cosmic millimeter background is the flux surface density, across the entire sky, from dust emission from all galaxies in the Universe. We stack the 1.16mm flux densities of a sample of dusty galaxies to determine the evolution of their contribution to the background. We resolve ∼ 35% of the background at 1.16mm and ∼ 50% of the background at 850 μm. We make two unique predictions for the redshift origins of the total 1.16mm background. Dust is responsible for more than the IR emission from a galaxy. The existence of dust is a necessary but not sufficient condition for the attenuation of a galaxy's intrinsic UV emission; the IR- and emergent UV-emitting regions must be spatially coincident. We establish a relation between the ratio of infrared to UV luminosity and β for dusty galaxies at z ∼ 2, which implies that their regions are coincident. We also argue that the dust is spread on galactic scales. In dust-poor galaxies at low redshift, the amount of dust attenuating the emission from ionizing stars is greater than the amount attenuating the emission from massive but nonionizing stars. For dusty galaxies at z ∼ 1.3, the amounts may be unequal--though this result is subject to the assumption that high-redshift dusty galaxies have the same spatial and grain size distributions as low-redshift dust-poor galaxies. The dust properties of high-redshift galaxies may be more diverse than they are in low-redshift galaxies.
    • Hafnium Oxide Films for Application as Gate Dielectric

      Jackson, Kenneth A.; Hsu, Shuo-Lin; Jackson, Kenneth A.; Potter, B. G.; Lucas, Pierre; O'Hanlon, John F. (The University of Arizona., 2005)
      The deposition and characterization of HfO2 films for potential application as a high-k gate dielectric in MOS devices has been investigated. DC magnetron reactive sputtering was utilized to prepare the HfO2 films. Structural, chemical, and electrical analyses were performed to characterize the various physical, chemical and electrical properties of the sputtered HfO2 films. The sputtered HfO2 films were annealed to simulate the dopant activation process used in semiconductor processing, and to study the thermal stability of the high-k films. The changes in the film properties due to the annealing are also discussed in this work.Glancing angle XRD was used to analyse the atomic scale structure of the films. The as deposit films are amorphous, regardless of the film thickness. During postdeposition annealing, the thicker films crystallized at lower temperature 600 C, and ultra-Thin (5.8 nm) film crystallized at higher temperature (600 - 720 C). The crystalline phase which formed depended on the thickness of the films. The low temperature phase (monoclinic) formed in the $10-20$ nm annealed films, and high temperature phase (tetragonal) formed in the ultra--thin annealed HfO2 film. The TEM cross-section studies of as deposited samples show the interfacial layer (< 1nm) exists between HfO2/Si for all film thicknesses. The interfacial layer grows thicker during heat treatment, and grows more rapidly when grain boundaries are present. XPS surface analysis shows the as deposited films are fully oxidized with an excess of oxygen. Interfacial chemistry analysis indicated that the interfacial layer is a silicon-rich silicate layer, which tends to transform to silica-like layer during heat treatment.I-V measurements show the leakage current density of the Al/as deposit-HfO2/Si MOS diode is of the order of 10^{-3} A/cm^2, which is two orders of magnitude lower than that of ZrO2 film with similar physical thickness. Carrier transport is dominated by Schottky emission at lower electric fields, and by Frenkel-Poole emission in the higher electric field region. After annealing, the leakage current density decreases significantly as the structure remains amorphous structure. It is suggested that this decrease is assorted with the densification and defect healing which accures when the porous as-deposited amorphous structure is annealed. The leakage current density increases of the HfO2 layer crystallizes on annealing, which is attributed to the presence of grain boundaries. C-V measurements of the as deposited film shows typical C-V characteristics, with negligible hystersis, a small flat band voltage shift, but great frequency dispersion. The relative permittivity of HfO2/interfacial layer stack obtained from the capacitance at accumulation is 15, which corresponds to EOT (equivalent oxide thickness)= 1.66 nm. After annealing, the frequency dispersion is greatly enhanced, and the C-V curve is shifted toward negative voltage. Reliability tests show that the HfO2* 0films which remain amorphous after annealing possess superior resistance to constant voltage stress and ambient aging.This study concluded that the sputtered HfO2 films are amorphous as deposited. The postdeposition annealing alters the crystallinity, interfacial properties, and electrical characteristics. The HfO2 films which remain amorphous structure after annealing possess the best electrical properties.
    • Half a Loaf: Generosity in Cash Assistance to Single Mothers across US States, 1911-1996

      Kenworthy, Lane; Nicoli, Lisa Thiebaud; Stryker, Robin; Ragin, Charles; Kenworthy, Lane (The University of Arizona., 2012)
      Prior to the establishment of Aid to Dependent Children in 1935, states offered cash assistance to single mothers and their children through locally administered programs known as mothers' pensions. Since the first mothers' pension law was passed in 1911, the rank-ordering of states' generosity has been remarkably stable, shifting only after welfare reform in 1996. Prior research has neither documented nor explained this remarkable path dependence. In this dissertation, I argue that states' racial and ethnic composition and their state capacity, as measured in the 1930s before the federalization of cash assistance to single mothers, set states on particular trajectories. To see how this operated in practice, I conducted a case study of benefit levels in Massachusetts from 1913 to 1996. I found that a constellation of factors at the beginning of mothers' pensions--the lack of a legislated maximum benefit level, state involvement in funding, and a competent professional bureaucracy--set Massachusetts on a trajectory toward being a generous state. The early years of Aid of Dependent Children reinforced this trajectory, as benefit levels were consistently raised due to cost-of-living increases. Things began to change in the 1960s, however, as the caseload grew, the state experienced a fiscal crisis, and welfare rights activists campaigned for higher benefit levels. Welfare rights activism generated a backlash that resulted in a lack of public support for adequate benefit levels. Benefit levels declined until the early 1980s, when a strong economy, savvy advocates, and sympathetic elected officials combined to increase benefit levels. The early 1990s recession, which began in 1988 in Massachusetts, instigated another decrease in benefit levels. Ultimately, the case study showed that states may appear to have solid trajectories, but these trajectories are contested. Both raising and lowering benefit levels came up in the Massachusetts Legislature many times, and a fundamental change in Massachusetts' state capacity, such as permanently reduced fiscal resources, could have sent Massachusetts down a different path.
    • HALL MOBILITY OF ALUMINUM OXIDE AT HIGH TEMPERATURES AND IN A RADIATION FIELD

      Green, Barry Adams, 1940- (The University of Arizona., 1972)
    • Halocarbons in ground water, Tucson, Arizona

      Randall, Jeffery Hunt.; Davis, Stanley N.; Simpson, Eugene S.; Long, Austin; Wilson, L. Gray; Moyers, Jarvis (The University of Arizona., 1983)
      Interest in halocarbons has been sparked by experimental evidence suggesting that these compounds are potential carcinogens and teratogens. The U.S. EPA started a nationwide program in 1970 to identify and quantify trace organic compounds in public water supplies and sewage effluents. To date no detailed large-scale areal ground-water surveys delineating concentrations of these halocarbons have been reported in the literature at the part per trillion level and below. The objectives of this dissertation are twofold: (1) identification, quantification, and detailed areal mapping of several halocarbon species in ground water near the Santa Cruz River northwest of Tucson, Arizona; and (2) development of halocarbon techniques for age dating recently recharged (0-40 years old) ground water. The halocarbon compounds considered are: trichlorofluoromethane (CC1₃F), dichlorodifluoromethane (CC1₂F₂), carbon tetrachloride (CC1₄), chloroform (CHC1₃), trichloroethylene (C₂HC1₃), methyl chloroform (CH₃CC1₃), and tetrachloroethylene (C₂C1₄). Objective (1) includes discussions of the areal halocarbon distributions detected in the ground water, their sources, and a qualitative comparison of the distributions to ground-water quality and land use patterns adjacent to the Santa Cruz River. Objective (2) utilizes the exponential atmospheric concentration buildup of CCl₂F₂, CC1₃F, and CCl₄, and the ratios of CCl₂F₂ to CCl₃F and CCl₄ to CCl₃F. Water samples from wells and the Santa Cruz River were collected in glass syringes and brought to the laboratory for analysis. An electron-capture gas chromatograph coupled to a gas stripping/concentration unit was used to quantify the halocarbons. Four high concentration areas were delineated, each probably associated with a different source: the CWUA area which was irrigated with sewage effluent during the 1960's; Rillito Creek (near its confluence with the Santa Cruz) which is a major ground-water recharge source; the Ina Road treatment plant/landfill/oxidation ponds area; and the Roger Road treatment plant "sewer farm" which is irrigated with sewage effluent. The CCl₂F₂ to CCl₃F ratio distribution indicates that most ground water in the study area is at least partially mixed with recharge less than 30 years old. The ground water adjacent to the Rillito has an apparent age of less than 10 years, in agreement with the CCl₃F distribution. Ground water in the Cortaro area has an apparent age of about 25 years, correlating with the start of irrigation in the area.
    • Halophytes for Bioremediation of Salt Affected Lands

      Zerai, Desale Berhe; Glenn, Edward P.; Fitzsimmons, Kevin M.; Nelson, Stephen G.; Collier, Robert J. (The University of Arizona., 2007)
      The area of secondarily salinized lands is increasing at a faster rate over time. Many irrigation districts around the world are shrinking as a result of secondarily salinized soils. This is resulting in crop yield losses. Irrigation practices with low drainage are intensifying this problem. Bioremediation of salinized soils with halophytes is one of the means of reversing this process. In these studies, we tested the growth and performance of four salt tolerant halophytes to varying levels of salinity. We analyzed the salt content of the plant tissues at different salinities, in order to determine how the plants' tissues reflect the increases in salinity. It was discovered that Allenrolfea occidentalis tolerates and grows well at higher salinities than the other plants tested. Furthermore, the concentration of salt in the aerial plant tissue was high and increased further in response to the external salt concentration. Halophytes such as A. occidentalis can be used to remediate abandoned salt affected lands and their biomass can have an added economic value. On the other hand, domestication of wild halophytes for agronomic purposes represents another opportunity to address the increasingly salinized soils and shortages of freshwater around the world. In these studies, we assessed the potential for improvement of an oilseed halophyte, Salicornia bigelovii, through selective breeding. We compared plant characteristics of S. bigelovii cultivars produced in breeding programs with wild germplasm in a green house common garden experiment. We concluded that S. bigelovii has sufficient genetic diversity among wild accessions and cultivars to support a crop improvement program to introduce desirable agronomic characteristics into this wild halophyte.
    • Halophytes for the treatment of saline aquaculture effluent

      Glenn, Edward P.; Brown, Jonathan Jed, 1964- (The University of Arizona., 1998)
      The discharge of untreated aquaculture effluent can pollute receiving water bodies. I tested the feasibility of using salt-tolerant plants (halophytes) with potential as forage and oilseed crops, as biofilters to treat saline aquaculture effluent. Plants were grown in draining lysimeters in greenhouses and irrigated with effluent salinized with NaCl. Irrigation water came from a recirculating tilapia culture system. I measured yield potential, water use and capacity for nitrogen and phosphorus uptake. In Experiment 1, Suaeda esteroa, Salicornia bigelovii and Atriplex barclayana (Chenopodiaceae) were grown in sand in 0.02 m³ lysimeters. Plants were irrigated with effluent of 0.5 ppt, 10 ppt and 35 ppt salinity, to meet evapotranspiration demand and to allow 30% of the applied water to leach past the plant root zone. Despite the high leaching fraction and short residence time of water in the pots, the plant-soil system removed 98% and 94% of the applied total and inorganic nitrogen, respectively, and 99% and 97% of the applied total and soluble reactive phosphorus respectively. For all species, salt inhibited (P ≤ 0.05) the growth rate, nutrient removal, and volume of water the plants could process. The salt marsh species S. esteroa and S. bigelovii performed better than the desert saltbush, A. barclayana, at 35 ppt. In Experiment 2, Suaeda esteroa, was grown in lysimeters containing approximately 0.8 m³ sandy loam soil and irrigated three times per week with 31 ppt NaCl effluent. I used five irrigation treatments, ranging in volume from 50 to 250% of the potential evaporation rate. Plant biomass and water consumption increased significantly (P ≤ 0.05) with increasing irrigation volume. Nitrate concentrations in water draining from the lysimeters decreased during the experiment, and were significantly lower in the high-volume treatments than in the low-volume treatments. Phosphorus concentrations in the leachate water increased during the experiment as a function of increasing irrigation volume. Irrigating halophyte crops with aquaculture wastewater of seawater-salinity may be a viable strategy for disposal of effluent.
    • Hamiltonian limits and subharmonic resonance in models of population fluctuations

      Schaffer, William M.; King, Aaron Alan (The University of Arizona., 1999)
      It is shown that the dynamics of models of predator-prey interactions in the presence of seasonality are profoundly structured by Hamiltonian limits, i.e., limiting cases where the flow satisfies Hamilton's canonical equations of motion. We discuss the dynamics at nonintegrable Hamiltonian limits, focusing on the existence of subharmonic periodic orbits, which correspond to multi-annual fluctuations. Perturbing away from a Hamiltonian limit, subharmonic periodic orbits are annihilated in tangent bifurcations, which compose the boundaries of resonance horns. All resonance horns emanate from the Hamiltonian limit and penetrate well into the realm of biologically-realistic parameter values. There, they indicate the "color" of the dynamics, i.e., the spectrum of dominant frequencies, whether the dynamics be regular or chaotic. Our observations provide both an account of the phase coherence often observed in population dynamics and a method for investigating more complex models of predator-prey dynamics, which may involve multiple Hamiltonian limits. This method is applied to the celebrated problem of the cyclic fluctuations of boreal hare populations. We present a model of the population dynamics of the boreal forest community based on known demographic mechanisms and parameterized entirely by measurements reported in the literature. The aforementioned method reveals the geometry potentially underlying the observed fluctuations. The model is quantitatively consistent with observed fluctuations. We derive specific, testable predictions of the model relating to the roles of herbivore functional response, browse abundance and regeneration, starvation mortality, and composition of the predator complex.
    • HaMMLeT: An Infinite Hidden Markov Model with Local Transitions

      Morrison, Clayton T.; Dawson, Colin Reimer; Morrison, Clayton T.; Barnes, Katherine Y.; Zhang, Hao (Helen) (The University of Arizona., 2017)
      In classical mixture modeling, each data point is modeled as arising i.i.d. (typically) from a weighted sum of probability distributions. When data arises from different sources that may not give rise to the same mixture distribution, a hierarchical model can allow the source contexts (e.g., documents, sub-populations) to share components while assigning different weights across them (while perhaps coupling the weights to "borrow strength" across contexts). The Dirichlet Process (DP) Mixture Model (e.g., Rasmussen (2000)) is a Bayesian approach to mixture modeling which models the data as arising from a countably infinite number of components: the Dirichlet Process provides a prior on the mixture weights that guards against overfitting. The Hierarchical Dirichlet Process (HDP) Mixture Model (Teh et al., 2006) employs a separate DP Mixture Model for each context, but couples the weights across contexts. This coupling is critical to ensure that mixture components are reused across contexts. An important application of HDPs is to time series models, in particular Hidden Markov Models (HMMs), where the HDP can be used as a prior on a doubly infinite transition matrix for the latent Markov chain, giving rise to the HDP-HMM (first developed, as the "Infinite HMM", by Beal et al. (2001), and subsequently shown to be a case of an HDP by Teh et al. (2006)). There, the hierarchy is over rows of the transition matrix, and the distributions across rows are coupled through a top-level Dirichlet Process. In the first part of the dissertation, I present a formal overview of Mixture Models and Hidden Markov Models. I then turn to a discussion of Dirichlet Processes and their various representations, as well as associated schemes for tackling the problem of doing approximate inference over an infinitely flexible model with finite computa- tional resources. I will then turn to the Hierarchical Dirichlet Process (HDP) and its application to an infinite state Hidden Markov Model, the HDP-HMM. These models have been widely adopted in Bayesian statistics and machine learning. However, a limitation of the vanilla HDP is that it offers no mechanism to model correlations between mixture components across contexts. This is limiting in many applications, including topic modeling, where we expect certain components to occur or not occur together. In the HMM setting, we might expect certain states to exhibit similar incoming and outgoing transition probabilities; that is, for certain rows and columns of the transition matrix to be correlated. In particular, we might expect pairs of states that are "similar" in some way to transition frequently to each other. The HDP-HMM offers no mechanism to model this similarity structure. The central contribution of the dissertation is a novel generalization of the HDP- HMM which I call the Hierarchical Dirichlet Process Hidden Markov Model With Local Transitions (HDP-HMM-LT, or HaMMLeT for short), which allows for correlations between rows and columns of the transition matrix by assigning each state a location in a latent similarity space and promoting transitions between states that are near each other. I present a Gibbs sampling scheme for inference in this model, employing auxiliary variables to simplify the relevant conditional distributions, which have a natural interpretation after re-casting the discrete time Markov chain as a continuous time Markov Jump Process where holding times are integrated out, and where some jump attempts "fail". I refer to this novel representation as the Markov Process With Failed Jumps. I test this model on several synthetic and real data sets, showing that for data where transitions between similar states are more common, the HaMMLeT model more effectively finds the latent time series structure underlying the observations.
    • HAND-HELD TONOMETER FOR TRANSPALPEBRAL INTRAOCULAR PRESSURE MEASUREMENT

      Enikov, Eniko; Polyzoev, Vasco; Peyman, Gholam; Mars, Matthew; Enikov, Eniko (The University of Arizona., 2011)
      This dissertation describes the development of a portable, hand-held tonometer for measurement of the intraocular pressure through the eyelid. The primary use of such device will be by people diagnosed with the eye disease glaucoma. Glaucoma is the second leading cause of blindness in the world and is asymptomatic to the patient in its early stages. This allows it to remain undiagnosed for prolonged periods, causing irreversible damage to the affected person's vision. Elevated intraocular pressure is the main risk factor associated with the development of glaucoma, and is currently the only symptom that is treatable for the slowing down or stopping of the progression to blindness caused by the disease. The effectiveness of the medications or procedures aimed at reducing the pressure to below risk levels is currently monitored through visits to the ophthalmologists' offices, which makes the frequent monitoring of the pressure inconvenient, expensive and sometimes impossible. Due to the variation of the pressure throughout the day and during different activities or food and beverage intake, the portability of the device is important in order to allow the user to carry it with them and take measurements as frequent as needed. The option to perform the measurement through the eyelid avoids direct contact with the eye, eliminating possible discomfort, the use of anesthetics, and the risk of contamination.Several designs and measuring concepts are evaluated using a custom made pressure regulation system. A series of prototypes have been built and tested and the results are reported in the respective sections of the dissertation. The final concept selected for the measurement technique was based on multiple force probe indentation and a custom MEMS-based force sensor for it was designed and tested.The main contributions of this dissertation are the design, fabrication and test of the prototype devices and the MEMS force sensors. The obtained results and experience described here can serve as a platform for further optimization and improvement of the device, and eventual development of a prototype capable of performing clinical research studies and passing FDA approval for home and clinical use.
    • The Hands that Rock the Cradle will Rise: Women, Gender, and Revolution in Ottoman Turkey, 1908-1918

      DARLING, LINDA T.; Atamaz Hazar, Serpil; DARLING, LINDA T.; CLANCY-SMITH, JULIA; BETTERIDGE, ANNE (The University of Arizona., 2010)
      Modern Turkish historiography has long claimed that Turkish women were fortunate, because they were granted equal rights by their benevolent leader Ataturk, without even having to ask or fight for them. This dissertation disproves that argument by demonstrating that Turkish women had been vigorously fighting for their rights well before the establishment of the Republic. While it is true that Turkish women had to wait until the 1930s to secure full legal rights, they had demanded gender equality since the Ottoman Revolution of 1908, followed by years of war, which together exerted a tremendous social and cultural impact on all strata of society, above all women. As such, this study addresses three main questions: How did the revolution transform women's social position as well as gender relations in Ottoman society? What role did the `woman question' and gender issues play in the formation of revolutionary politics and discourse in the late Ottoman Empire? Finally, how did Ottoman women participate in shaping, transforming, enforcing, and/or challenging the objectives of the revolution?I argue that the 1908 Revolution triggered significant changes in the Ottoman public discourse, political agendas, and the organization of daily life concerning gender equality and that Turkish women, taking advantage of the new venues and opportunities provided by the revolution in effective and innovative ways, played a vital role in creating and implementing this change. Studying the ideas and actions of a large number of upper and middle class Turkish women as well as the government's attitude towards women between 1908 and 1918, I demonstrate that women in the late Ottoman society were far from being passive, powerless, and silent, as the nationalist historiography has claimed they were. I reveal that, on the contrary, these women were active participants in the revolutionary process, in the struggle for equal rights, and consequently in the construction of a new political regime, a new social order, and their own roles in this new context.
    • Hansel und Gretel

      Asia, Daniel; Nichols, Joshua Daniel; Mugmon, Matthew; He, Yuanyuan (The University of Arizona., 2021)
      Hansel und Gretel, a symphonic poem for wind ensemble, is an original musical composition based on the innovations of the symphonic poem genre. This work is written for piccolo, two flutes, two oboes, English horn, two clarinets (in B-flat), bass clarinet, two bassoons, contrabassoon, two alto saxophones, tenor saxophone, baritone saxophone, three trumpets, four horns, two trombones, bass trombone, euphonium, tuba, double bass, timpani, crash cymbals, suspended cymbal, snare drum, bass drum, and large gong. It is divided into four movements. The form is very similar to the Romantic Era symphony, consisting of an Introduction–Allegro, Adagio, Scherzando, and Finale. Due to the flexibility of the wind ensemble genre as having a primarily educational instrumentation, parts such as flute, clarinet, euphonium, and tuba can be doubled. The work is semi-programmatic, following the adaptation of the narrative of “Hansel and Gretel” as a traditional fairy tale published by the Brothers Grimm in 1812 in Grimms' Fairy Tales. The composition features elements of absolute music, in that there are no strict leitmotifs nor other explicit mentions of characters, programmatic development of character themes, or literal-musical verbosity, such as a guillotine in Berlioz's Symphonie Fantastique. All themes are original and do not intentionally quote other works, though moments of musical parody pervade the work (e.g., Dies irae in movement two, Stravinsky's Danse sacrale (L'Élue) from Le Sacre du printemps in movement three). All examples provided in the appendix are given in transposed pitch (unless otherwise indicated).
    • Happy Hearts Automatic Referral

      Shea, Kimberly D.; Krmpotic, Kim; Shea, Kimberly D.; Shea, Kimberly D.; Carlisle, Heather L.; Ota, Ken (The University of Arizona., 2015)
      Happy Hearts Automatic Referral (HHAR) was a program that referred heart failure (HF) patients to Transitional Care (TC) at Banner Health. The purpose of the human subject’s research was to examine the use of the Minnesota Living with Heart Failure® questionnaire (MLHFQ) as a survey instrument to identify moderate quality of life (QOL) in patients living with HF. The most common referral to TC prior to the project was patients with poor QOL. The project explored the influence of earlier referrals to improve QOL for participants living with HF. The MLHFQ was chosen because it is a valid and reliable instrument specific to QOL. The HF population was chosen because the most commonly referred patients to interventions such as TC are those that pose the smallest risk for readmission, have the highest risk of readmission, or have the potential to demonstrate the most significant increase in QOL. By offering TC to patients with moderate QOL, an opportunity existed to reduce advancement into a population that is characteristic of high-risk readmissions. The project identified potential participants, then administered the MLHFQ, and scored it. When scores were between 26 and 45, participants were considered qualified participants for this project. Ideally, the patient would have been enrolled in TC for 30 days and the project would have administered another MLHFQ at completion of 30 days of TC to evaluate a change in QOL; however, due to the short-term nature of this project the TC content and follow-up administration of the MLHFQ was not evaluated. Also, while this project was taking place the TC team at Banner Health was not accepting new patients. A human subject’s research approach was applied and examined the responses to the MLHFQ from a small sample of five moderate QOL participants and described the expected responses for improved QOL if a second MLHFQ was to be administered following TC. Specifically items 1, 7, 8, 14, and 19 were examined to discuss how TC interventions might have improved scores on these items. The project concluded by describing how future cycles should be completed for further research.
    • "Hapwan chanaka" ("on top of the earth"): The politics and history of public ceremonial tradition in Santa Teresa, Nayarit, Mexico

      Sheridan, Thomas E.; Coyle, Philip Edward, 1961- (The University of Arizona., 1997)
      This dissertation charts historical changes in the ceremonial institution that the Cora people of the town of Santa Teresa refer to as their costumbre, and links these changes to recent violence in that town. This cultural history begins with a description of the ceremonies through which cognatic descent is reproduced in Santa Teresa today. The performance of these mitote ceremonies positions core ceremonial participants both spatially, in relation to a meaningful territory, and temporally, in relation to sets of still-active deceased ancestors and ancestral deities, as members of distinct "maize-bundle groups". During the Lozada Rebellion of the 19th century, after a relatively brief mission period, Catholic-derived ceremonialism was integrated with this mitote ceremonialism by the ancestors of today's living Coras. This integrated costumbre expanded and reoriented the symbolic connotations produced in maize-bundle group ceremonies, creating a sense of hierarchical and synecdochical inclusiveness between particular descent groups and the "higher" courthouse officials of the community as a whole. After the fall of Manuel Lozada's military confederacy, these community-level ceremonial traditions became a battleground within a long-term factional struggle between intruding non-indigenous people (and their Tereseno supporters) and the other Teresenos who opposed the policies of these outsiders. This relatively clear-cut political factionalism splintered after the Instituto Nacional Indigenista entered into this factional conflict during the 1960s. This federal agency pushed through a series of political initiatives and development projects with little or no input from Teresenos, and so also eroded the willingness of local people to put out the effort required to properly continue their ceremonial traditions. In recent years Teresenos have responded to this community-level political vacuum, and the drunken violence that has come with it, by retreating from the "dirty" community-level ceremonial festivals to the more private and orderly mitote ceremonies celebrated by their own maize-bundle groups. In this way, the costumbre has acted as a fault-line dividing and fracturing the community; the ancestral ceremonial traditions that once established an inclusive territory and ancestry linking all Teresenos are now helping to produce a series of cleavages that are driving the splintered Tereseno community ever more apart.
    • HAR DAYAL: A PORTRAIT OF AN INDIAN INTELLECTUAL

      Brown, Emily C. (Emily Clara) (The University of Arizona., 1967)