Now showing items 21-40 of 38380

    • Understanding Atmosphere-Ocean-Land-Ice Interactions in the Earth System

      Zeng, Xubin; Reeves Eyre, James Edward Jack; Behrangi, Ali; Castro, Christopher L.; Russell, Joellen L. (The University of Arizona., 2020)
      As numerical models of the Earth system become more sophisticated – in terms of number of component models and the complexity of physical processes simulated – it becomes more difficult to understand their biases. This is especially true for near-surface quantities such as 2-meter temperature and wind speed that are influenced by interface processes. This dissertation consists of four studies that address this difficult problem. All span multiple components of the Earth system and are global in scope, making use of global observational data sets and Earth system models (ESMs). Earth system models parameterize ocean surface fluxes of heat, moisture and momentum with empirical bulk flux algorithms, which introduce biases and uncertainties into simulations. We compare, for the first time, the effects of three different algorithms in both atmosphere and ocean model simulations using E3SM. Flux differences between algorithms are larger in atmosphere simulations (where wind speeds can vary) than ocean simulations (where wind speeds are fixed by forcing data). Surface flux changes lead to global scale changes in the energy and water cycles, notably including ocean heat uptake and global mean precipitation rates. Compared to the control algorithm, both the Coupled Ocean-Atmosphere Response Experiment (COARE) and University of Arizona (UA) algorithms reduce global mean precipitation and top of atmosphere radiative biases. Ocean barrier layers (BLs) separate the mixed layer from the top of the thermocline and are able to insulate the mixed layer from entrainment of cold thermocline water. Here, we provide the first global BL assessment in three ESMs. Compared to observations, models reproduce the global distributions as semipermanent features in some tropical regions and seasonal features elsewhere. However, model BLs are generally too thin in tropical regions and too thick in higher latitudes. BL thickness biases are related to atmosphere biases in the tropics, but at higher latitudes biases are dominated by ocean circulation errors. Global and regional water cycle is a crucial component of the Earth system, and numerous studies have addressed the individual components (e.g., precipitation). Here we assess, for the first time, if remote sensing and reanalysis data sets can accurately and self consistently portray the Amazon water cycle. This is further assisted with satellite ocean salinity measurements near the mouth of the Amazon River. Ensemble means, which are widely used for individual components, are found to produce large biases in water cycle closure. Closure is achieved with only a small subset of data combinations, which rules out the lower precipitation and higher evaporation estimates. The common approach of using the Obidos stream gauge (located hundreds of kilometres from the river mouth) to represent the entire Amazon discharge is found to misrepresent the seasonal cycle, and this can affect the apparent influence of Amazon discharge on tropical Atlantic salinity. Near-surface air temperature (SAT) over Greenland has important effects on mass balance of the ice sheet. Here, extensive in situ SAT measurements (~1400 station-years) are used to assess monthly mean SAT from sixteen global and regional products. Ice sheet-average annual mean SAT from different data sets are highly correlated in recent decades, but their long term means and trends differ enough to affect results of ESM evaluations. Compared with the best observational estimate, thirty-one ESM historical runs from the CMIP5 archive reach ~5 degrees Celsius for 1901–2000 average bias and have opposite trends for a number of sub-periods. In the course of the above studies, my other research contributions have included model development and evaluation activities for the DOE E3SM Coupled Model Version 1, analysis of subtropical cloud errors in the E3SMv1 Atmosphere Model, and analysis of Greenland ice sheet surface interface processes in the Regional Arctic System Model.
    • Comprehensibility of Game Rulebooks: Perspectives from a Community of Practice

      Short, Kathy G.; Niecikowski, David Matthew; Gilmore, Perry; Jaeger, Elizabeth L. (The University of Arizona., 2020)
      This qualitative study was contextually framed within a community of practice consisting of the traditional board and card game community members. The findings were developed through constructivist grounded theory and Delphi survey methodology in response to these two research questions: (1) As a community of practice made-up of traditional game players and professionals, what are their recommendations on comprehensible rulebook features to meet readers’ needs? (2) In what ways do published rulebooks reflect these identified rulebook comprehensibility features? The dissertation’s salient finding is the Comprehensible Features of Rulebooks Performance List co-constructed by members in the traditional gaming community of practice made-up of 21 solicited surveyed industry experts and informed by unsolicited public forum comments by 541 users on the website Boardgamegeek. The evaluation results of eight published rulebooks are discussed using the performance list’s 92 weighted features organized into 10 categories. Additional findings were developed from the performance list that include: Interdependence of Referencing to Support Readers’ Memory, Power Features, and Predicting Intended Audience Satisfaction with Rulebook Comprehensibility Score. The findings have immediate implications for evaluating the comprehensibility of game rulebooks and guide possible rulebook revisions and/or the creation of supplemental reader supports. These findings can also inform future research on designing comprehensible rulebooks and observing readers’ actions with rulebooks modified by the performance list to meet readers’ needs. Broader implications include employing this study’s synthesized contextual framework and research methodology to develop a solution to a community of practice’s shared concern.
    • Global Assessment of Rain Gauge Undercatch Correction Factors and Comparative Analysis of Snowfall Accumulation Using Diverse Data Sets: In-Situ, Satellite, and Reanalysis

      Behrangi, Ali; Gupta, Hoshin Vijai; Panahi, Milad; Niu, Guo-Yue (The University of Arizona., 2020)
      Despite its importance for hydrology and water resources, accurate estimation of snowfall rate over snow-covered regions has remained a major observational challenge from both in-situ and remote sensing instruments. Snowfall accumulation can be measured by either accumulating snowfall estimates or measuring snowpack properties such as Snow Water Equivalent (SWE) and mass. By focusing on snowfall over snow accumulation period and using case studies and long-term average (2003 to 2015) over CONUS, the first phase of our study compares snowfall accumulation from gauge stations (using GPCC and PRISM products), satellite products (GPCP and the suite of IMERG products), and reanalysis (ERA-interim, ERA5, and MERRA-2). Changes in SWE, based on the recent UA-SWE product and mass change observations from the Gravity Recovery and Climate Experiment (GRACE), were used for assessment of precipitation products for snowfall estimation. In the second phase of our study we assess two popular rain gauge undercatch correction factors (CFs) used in the Global Precipitation Climatology Centre (GPCC) monitoring and the Global Precipitation Climatology Project (GPCP) products, and quantify how much the choice of the CFs can impact our total estimate of precipitation over land at seasonal, annual, regional, and global scales. Rain gauges are critical for measuring precipitation rates at regional and global scales and are often used to calibrate precipitation rates estimated from other instruments such as satellites. However, precipitation measured at rain gauges are affected by gauge undercatch that is often larger for snowfall than rainfall. The main results include: (1) Based on UA-SWE and GRACE analysis over cold regions in the CONUS: Snow accumulation from most of the products is bounded by GPCC with and without correction, highlighting the critical importance of selecting proper CFs for gaugeundercatch correction. The CF based on Legates and Willmott method used in GPCP was found to be more consistent with the SWE-based analysis than CF based on the Fuchs method. Reanalysis products show very similar spatial pattern among themselves, but represent a large variation in simulating snow accumulation, with ERA-interim showing the least accumulation and MERRA-2 showing the highest accumulation and closest to the snow accumulation suggested by SWE. (2) Based on Global rain gauge analysis: Overall CFs are largest in higher latitudes and in winter when snowfall is dominant. The CFs are also compared with respect to the environmental variables used in their development, among those are near surface air temperature, relative humidity, and wind speed. Results show that the correction factors can increase the annual precipitation rate based on rain gauges by about 8%, although this amount can vary from about 3% (in boreal summer) to 10% (in boreal winter), depending on the season and the method used for gauge undercatch correction. It was also found that annual variations in CFs can be large, so the use of climatology CFs, like the one used in GPCP, requires caution.
    • Mathematical Modeling of Induction Thermoforming Process for Radio Telescope Panels Manufacturing

      Chan, Cholik; Bani Issa, Abd Alrhman Mohammad; Ganapol, Barry; Li, Peiwen (The University of Arizona., 2020)
      Obtaining a high-efficient, low-cost, and time-saving method for manufacturing radio telescope primary reflectors is one of the most considerable obstacles for further progress in this area. In addition to the above, the lack of literature in this subject presents another problem, as the currently available manufacturing methods are considered trade secrets by their owners. To that end, the novel process of induction thermoforming was developed in the Steward Observatory Solar laboratory at the University of Arizona. This method offers potential advantages over the existing means of shaping curved metallic sheets. The main objective of this work is to develop and implement a numerical study to verify the performance of the proposed method. Hence, a mathematical model of the induction thermoforming was constructed. Finite element analysis (FEA) was implemented with the aid of ANSYS software to solve and analyze the model for a prototype plate with dimensions 120×120×3 mm. The simulation technology was developed by integrating the electromagnetic and thermal analysis modules in ANSYS. Comparing the results with those given by the existing experimental data shows an agreement, with a relative percentage error of less than 12% in temperatures data. Several numerical simulations were performed for many cases to study the effect of coil current, frequency, coil to plate distance, and heating time in the system performance. The research in this field is still at the beginning and has not been deeply investigated yet. It needs more improvements to obtain better control in system parameters and improve the process efficiency.
    • Tectonic Evolution of the Bhumichula Plateau: A High-Elevation Low-Relief Surface in Western Nepalese Himalaya

      DeCelles, Peter G.; Lama Sherpa, Tshering Zangmu; Carrapa, Barbara; Quade, Jay (The University of Arizona., 2020)
      The Bhumichula plateau is an anomalously high elevation low-relief (HELR) surface at >4000 m in the midst of the western Nepalese Himalayan fold-thrust belt. The plateau is situated in the northeastern part of the Dadeldhura klippe, an erosional outlier of Greater Himalayan high-grade metamorphic rocks surrounded by low-grade, structurally underlying Lesser Himalayan rocks. Using low-temperature thermochronology, we test whether the Bhumichula HELR surface formed at low elevation and was later uplifted, developed in situ at high elevation following tectonic disturbance, or if it is a remnant of an older, more extensive HELR that has been shrinking due to recent tectonically driven incision. Average apatite (U-Th)/He ages are ~6 Ma on both the plateau surface and along the valleys that cut through the surrounding region, whereas apatite fission track ages are ~7-9 Ma on the plateau surface and ~11-14 Ma on the flanks. Thermal modeling suggests that the main period of exhumation and erosion was ~14 Ma for the valley bottom samples in the southwest limb of the klippe and ~7 Ma for Bhumichula plateau in the northeast limb of the klippe, consistent with the timing of slip on the Ramgarh thrust and initial growth of the Lesser Himalayan Duplex (LHD), respectively. Spatial differences in the timing of cooling for the northeast and southwest limbs of the klippe 24 is interpreted to indicate heterogenous exhumation due to structural variation. Slow exhumation since ~7 Ma on the Bhumichula plateau suggests attainment of high elevation by mid-Miocene time. Exhumation and uplift ~7 Ma due to growth of the LHD is therefore likely to be responsible for drainage reorganization and resulting preservation of low-relief at Bhumichula due to a combination of fluvial and glacial processes.
    • Raising Intercultural Consciousness through Literary Dialogue in a Second Language Classroom

      Warner, Chantelle; Alfred, Olapeju Oseyemi; Gramling, David; McGregor, Janice (The University of Arizona., 2020)
      Scholars have long discussed the use of literature in (inter)cultural awareness raising/teaching in foreign language teaching. This MA thesis presents a study conducted in two beginning German language classes, in which literary texts thematizing minority perspectives were implemented in order to raise students’ intercultural awareness. The classroom-based study combines literary reading, digital social media, and peer dialogue. Data obtained from learners’ comments on google documents from classroom discussions, show evidence of learners’ emergent intercultural awareness, and an analysis of student response surveys indicate that learners had a positive experience working collaboratively. This study therefore demonstrates that literary texts can be used in beginner classes in foreign language classrooms to teach intercultural awareness.
    • "Within and Without His Religion": The Formation of the Colonial Mexican Jesuits, 1600-1650

      Lotz-Heumann, Ute E.; Plummer, Marjorie E.; McClain, Hannah Grace; Gosner, Kevin M. (The University of Arizona., 2020)
      This thesis examines processes of identity formation among the colonial Mexican Jesuits in the first half of the seventeenth century. Recent historiography has emphasized the central role played by the early modern Jesuits in European imperial and missionary expansion. While the global significance of the Society of Jesus is asserted in these works, little attention has been paid to the identity and day-to-day activities of the Jesuits, especially as these were religious in nature. This project seeks to address this gap in the literature by closely analyzing Jesuit identity as it was conceived and performed in the province of New Spain. Utilizing contemporary manuscript and print sources composed by the Jesuits, this thesis explores the ways in which Jesuit priests formed their identity through both internal discourses and external interactions in colonial Mexican society. It accomplishes this through a social and cultural analysis of the Mexican Jesuit community as a whole, while also referring to a comparative case study of an individual Jesuit in the province, namely the Irish-born Padre Miguel Godínez. By examining identity at the level of the individual and the group, this thesis argues that a distinctly Jesuit identity was formed internally through a textual discourse of perfection that required constant negotiation. Externally, Jesuit identity was formed through social interactions with other actors in colonial Mexico, including the indigenous subjects of the Jesuit mission. As missionaries, the Jesuits constructed an identity that prioritized sacramental and pastoral duties within local communities, duties that were simultaneously logistical and spiritual. By providing a clearer view of the colonial Mexican Jesuits as they understood themselves, this study enriches our grasp of transregional early modern phenomena, particularly global Catholicism.
    • We're All Americans Now: How Mexican American Identity, Culture, and Gender Forged Civil Rights in World War II and Beyond

      Morrissey, Katherine G.; Steptoe, Tyina; Key, Lora Michelle; Perez, Erika; Hemphill, Katie (The University of Arizona., 2020)
      “We’re All Americans Now: How Mexican American Identity, Culture, and Gender Forged Civil Rights in World War II and Beyond,” argues that World War II was a pivotal moment in the history of race formation and civil rights activism in the Southwest. This dissertation focuses on middle-class Mexican Americans in three Southwest-border cities: Los Angeles, Tucson, and El Paso and how they used wartime necessities to insert themselves into local and national politics to advocate for themselves and all Mexican Americans. These three Southwest cities provide an important case study that highlights class, gender, and race, showing the relationships between middle-class and working-class Mexican Americans, as well as their relationships with Anglos during the war. This project centers on Tucson, with its distinct construction of a historically powerful middle class, while the comparisons to El Paso and Los Angeles highlight the structural and philosophical differences that existed in Mexican-American communities across the Southwest. Divergences of segregation and discrimination in these three cities shaped Mexican Americans’ racial subjectivities and their activism during the war. Middle-class Mexican Americans used their claims to racial whiteness to establish relationships with city and state officials in order to advocate for working-class Mexican Americans. Within that representation, however, the middle class often had to defend Mexican-Americans’ relationship with Mexico and demonstrate their patriotism. Mexican-Americans’ wartime activism led directly to grassroots civil rights programs and agendas that centered squarely on each community’s needs and constraints. As a regionally centered study, this works redefines civil rights activism and the larger understandings of the Mexican-American experience.
    • Un bilan de la Compétence Symbolique chez les Apprenants du Français Langue Seconde

      Knisely-Southerland, Kris; Gorham, Julia Anne; Price, Joseph; Dupuy, Beatrice (The University of Arizona., 2020)
      La notion de compétence est une idée pour laquelle il existe plusieurs conceptions dans le domaine de l’apprentissage et l’enseignement des langues secondes (L2). Depuis le travail de Chomsky (1965) sur la distinction entre la compétence et la performance, les chercheurs ont été nombreux à formuler de nouvelles définitions de la compétence. On passe, alors de la compétence socioculturelle (Bourdieu, 1991) à la compétence interculturelle (Byram, 1997 ; Deardorff, 2009) et plus récemment à la compétence symbolique (Kramsch, 2006, 2009). Ce dernier concept souligne l’importance de la capacité des étudiants des L2 de reconnaître et de subvertir le pouvoir et la hiérarchie. Plus précisément, il s’agit de « the ability to manipulate symbolic systems, … and to position oneself to one’s benefit in the symbolic power game » ainsi que la capacité de réfléchir sur sa propre position dans le monde. Cette compétence, grâce à son emphase sur le pouvoir et la violence symbolique, est essentielle pour tout étudiant dans cette époque de « nouveau capitalisme » (Cope & Kalantzis, 2009). Il est alors surprenant que, malgré de multiples études précédentes conceptualisant la compétence symbolique au niveau théorique, on constate un manque important d’études examinant le côté pratique de celle-ci dans les cours de L2 et même plus son développement et son évaluation chez les apprenants du français. La littérature existante démontre néanmoins une relation entre la compétence symbolique et l’utilisation d’une approche pédagogique basée sur les littératies multiples et multimodales (Étienne et Vanbaelen, 2017 ; Kearney, 2010). Alors, l’étude présente vise à contribuer aux recherches cruciales sur ce sujet en répondant aux questions suivantes : 1) Est-ce que les étudiants démontrent des indices de la compétence symbolique en visionnant des films francophones, en complétant des questions d’analyse et en maintenant des journaux de réflexion et si oui, lesquels ? et 2) Quelles stratégies cognitives ou réflexionnelles sont utilisées par les étudiants, consciemment ou non, lorsqu’ils démontrent la compétence symbolique, s’ils en utilisent ? Afin de répondre à ces questions, des données ont été recueillies auprès de deux sections d’étudiants (N = 27) inscrits en quatrième semestre de français langue seconde à une grande université publique dans le sud-ouest des États-Unis en automne 2019. Une séquence pédagogique de multilittératies a été créée à partir de trois films francophones – Bienvenue chez les Ch’tis (2007), Bienvenue à Marly-Gomont (2016), et Divines (2016), choisis parce qu’ils abordent les thèmes de la diversité, l’altérité et l’identité. Les données récoltées comprennent des fiches de travail analytiques sur les trois films ainsi que des journaux de réflexion complétés par les étudiants et l’enseignante, des entretiens avec des étudiants consentants après la fin du semestre et des informations démographiques. Pour analyser ces données qualitatives, un processus consistant de trois cycles de codage, ouvert, axial et sélectif, a été adopté. Les résultats suggèrent que la compétence symbolique se manifeste souvent sous la forme des capacités de manipuler des biens symboliques (les émotions et expériences ainsi que les identités et affiliations), de créer de la complexité et d’analyser la forme et moins souvent sous la forme de la tolérance de l’ambiguïté. Ces indices se manifestaient lorsque les participants ont abordé une variété de stratégies largement classables dans trois catégories : les stratégies d’analyse, de réflexion, et d’écriture. Pour résumer, les résultats de cette étude indiquent que la vaste majorité des participants ont démontré au moins certains indicateurs de la compétence symbolique au fil des activités pédagogiques, ce qui suggère que celles-ci ont la capacité d’encourager les habilités supérieures de la pensée.
    • Dans le Corps du Texte : Le Roman Francophone comme Perversion Libératrice (Lectures dans L'œuvre D'abdellah Taia, Leila Silmani et Nelly Arcan)

      Provencher, Denis M.; Rebhi, Salma; Taoua, Phyllis; Mouzet, Aurelia (The University of Arizona., 2020)
      Ce présent travail explore la perversion sexuelle dans l’œuvre romanesque d’Abdellah Taïa, de Nelly Arcan et de Leila Slimani. En comparant ces trois œuvres, nous prouvons que l’excès dans la perversion sexuelle des personnages clefs des trois romans Infidèles (2012), Putain (2010) et Dans le jardin de l’ogre peut se lire comme la réflexion de l’excès dans la perversion des sociétés dans lesquelles vivent au quotidien ces auteurs. En d’autres termes, nous prouvons que l’homophobie de la loi pénale et la marginalization des personnes gays au Maroc,la putophobie et la misogynie des milieux socio-culturels au Canada, ainsi que la reclusion et l’aliénation des générations issues de l’immigration maghrébines au sein de la France, bien qu’ils soient des formes différentes d’oppression, engendrent dans l’œuvre des trois écrivain.e.s des figures fictives similaires d’un personnage principale qui vit son corps charnel comme corps-souillure qui se révolte contre l’injustice par une rébellion primordialement sexuelle. Cette rébellion est étudiée en tant qu’apanage romanesque pour une transgression créative à travers de laquelle des auteur.e.s expriment leurs malaises devant la perversite des pays où ils vivent et dont les formes de corruptions politiques et sociales normalisent des tares et désagrègent des droits humains essentiels. This work explores the different manifestations of sexual addiction and erotic perversions in Infidels ( 2012) by Abdellah Taïa, Whore (2001) by Nelly Arcan and Adele (2014) by Leila Slimani. By comparing and contrasting these three novels, we prove that the forms of sexopathy experienced by the main characters are reflections of socio-cultural, political and intellectual perverse forms of oppression endured by these authors while living in their home countries. In other words, we prove that the homophobic judicial system and the marginalization of gay people in the Moroccan society, the putophobia and the misogyny of the intellectual and socio-cultural milieux in Canada, as well as the seclusion and the alienation of generations of French citizens from Maghrebi immigrant background, all contribute to the creation of similar fictitious figures whose excessive masochistic sexual addiction is a rebellious answer to the injustice they live on a daily basis because of their gender identity and/or their ethnic origins. This rebellion is studied as a romantic appanage for a creative transgression through which such authors express their rejection of the perversity of their countries where political and social corruptions normalize violence and marginalia essential human rights.
    • The Fate of Nitroaromatic Contaminants in Anaerobic Environments: Formation of Coupling Products between Reduced Nitroaromatic Intermediates and Covalent Bonding of Aromatic Amines to Humus Model Compounds

      Sierra-Alvarez, Maria Reyes; Field, James A.; Kadoya, Warren; Farrell, James; Mash, Eugene A.; Abrell, Leif M. (The University of Arizona., 2020)
      Nitroaromatic compounds are a class of toxic, synthetic chemicals used in a variety of industries, including explosives, pharmaceuticals, and pesticides. They may enter the environment through wastewater discharge or deposition onto soil surfaces, i.e. on firing ranges. Rainwater can dissolve nitroaromatics and transport them into the subsurface, where they may encounter anaerobic conditions. There, soil microbes and/or reduced minerals may catalyze the reduction of nitroaromatics to aromatic amines via three, two-electron transfers per nitro group. This study builds on previous work on the fate of 2,4-dinitroanisole (DNAN), an insensitive munitions compound that is replacing trinitrotoluene (TNT) in explosives formulations to reduce the risk of accidental detonations. It was found that DNAN formed azo dimers and trimers, which can be more toxic than nitroaromatic compounds, when incubated in anaerobic sludge and soil. Furthermore, 14C-radiolabeled DNAN became immobilized to the insoluble fraction of soil organic matter (humus) in soil incubations, which was enhanced under reducing conditions. This could be used as a strategy to “remove” nitroaromatics from the subsurface environment. The objective of this work is to understand the mechanisms that caused DNAN to form azo compounds and become incorporated into humus in anaerobic incubations. The hypothesis was that once DNAN became reduced biologically (catalyzed by microbes), abiotic nucleophilic substitution reactions occurred, either between reduced intermediates of DNAN to form azo compounds or between humic moieties, such as quinones, and DNAN-derived aromatic amines to form “bound residues.” These reactions were originally thought to take place only under aerobic conditions, with aromatic amines forming free radical species. We conducted biological incubations of 4-nitroanisole in anaerobic granular sludge and chemical pairing experiments between reduced 4-nitroanisole intermediates, 4-nitrosoanisole and 4-aminoanisole, and between aromatic amines, including those resulting from DNAN reduction, and model quinone compounds. Using ultra-high performance liquid chromatography, UV-Vis spectroscopy, and mass spectrometry, we studied reactant disappearance and product formation. In anaerobic sludge incubations of 4-nitroanisole, azo dimer 4,4ʹ-dimethoxyazobenzene formed but was subsequently reductively cleaved. Hypothesizing that the formation of this azo dimer was due to the chemical coupling of 4-nitroanisole reduced intermediates 4-nitrosoanisole and 4-aminoanisole, we incubated these compounds in abiotic, anoxic conditions. Although 4,4ʹ-dimethoxyazobenzene formed, the major product was 4-methoxy-4ʹ-nitrosodiphenylamine, another coupling product. We studied the toxicity of these two products to Aliivibrio fischeri and found that they were orders of magnitude more toxic than reactants 4-nitrosoanisole and 4-aminoanisole. In studies chemically pairing aromatic amines, which would result from nitroaromatic reduction, with quinone compounds that model humus, we detected the formation and accumulation of covalently-bonded Michael adducts and imines resulting from nucleophilic addition pathways. These results provide insight into the mechanisms through which DNAN molecules both bind to each other and to quinone moieties present in humus as they are sequentially reduced to aromatic amines. To prevent the accumulation of toxic coupling products and enhance immobilization to humus on sites contaminated with nitroaromatics, anaerobic conditions should be created, along with the addition of electron donor and organic carbon amendments to promote reducing conditions, which both cleave coupling products and generate aromatic amines, and increase humus content, respectively.
    • Substrate Composition Effect on Growth of Cotinis Mutabilis Larvae: A Case for Detritivore Scarabs in the Insect Agriculture Industry

      Davidowitz, Goggy; Slagle, Meck L.; Hunter, Martha; Schuch, Ursula; Wheeler, Diana (The University of Arizona., 2020)
      Edible insects have great potential in alleviating some of the food insecurities that are increasing globally. Many cultures eat wild-harvested insects which is contributing to declining insect populations and increasingly fragile food webs and ecosystems. Insect agriculture (farming) is a solution to many associated issues with wild harvesting. Insect farming can also help reduce landfill loading with food loss and waste (FLW) which is nearly 33% of all food produced globally. Farming of detritivore insect species, those that can consume decaying organic material including manures, increases the economic and environmental sustainability of the insect agriculture industry. The Green Fig Beetle (Cotinis mutabilis, Scarabaeidae) is a native to the Sonoran Desert in the United States of America and Mexico. This study explored the effects of organic waste diets on the growth and survivorship of the larvae to evaluate if C. mutabilis is a viable and sustainable candidate for insect farming. Scarabs are found globally and have similar life histories; therefore, this study can be used for modeling rearing protocols, especially in arid regions.
    • Mad Mark Twain: Rage and Rhetoric in the Life and Works of Samuel L. Clemens

      Jenkins, Jennifer L.; Fredericks, Sarah Elizabeth; Hurh, Paul; Abraham, Matthew (The University of Arizona., 2020)
      Interweaving literary biography, rhetoric, and emotion studies, this dissertation argues that anger was fundamental to Mark Twain’s social and literary epistemologies. Although scholars have largely dismissed his temper as anecdotal, Twain considered anger vital to maintaining social order and strategically employed angry rhetoric in his personal and professional writings. Neither irrational nor haphazard, Twain’s vitriol demonstrates remarkable rhetorical awareness and literary artistry. Whether haranguing his publishers about dwindling profits or eviscerating his private secretary Isabel Lyon in the little-known Ashcroft-Lyon Manuscript, Twain weaponized his emotions utilizing classical Aristotelian theories of persuasion. Moreover, many defining literary tropes of Twain’s most celebrated works originated in these angry texts, further cementing their importance to his literary development. Through close reading of his newspaper articles, letters, and autobiographical texts, this study traces evolving rhetorical patterns in Twain’s vituperation and demonstrates how his anger script impacted his participation in nineteenth-century literary culture.
    • The Impacts of Climate on the Past, Present, and Future Distributions of Species in the American Southwest and Its Madrean Sky Island Archipelago

      Moore, Wendy; Yanahan, Alan; Brown, Heidi E.; Dlugosch, Katrina M.; Guertin, David P. (The University of Arizona., 2020)
      The southwest United States (US) has a complex geologic and climatic history that have affected the diversity and distribution of species throughout the region. The ground beetle (Coleoptera: Carabidae) Synuchus dubius (LeConte, 1854) is a flightless species restricted to high-elevation (>1800 meters) conifer forests and has a widespread, yet fragmented distribution across the southwest US. Phylogeographic analyses revealed multiple diverging lineages that resulted largely from climate oscillations during the Pleistocene Epoch. S. dubius is not the only species in the southwest US with unique genetic lineages. Many others also have cryptic diversity, especially in the Madrean Sky Island Archipelago (Madrean Archipelago). This region is a biodiversity hotspot located in southeastern Arizona, southwestern New Mexico, and northern Sonora, Mexico. With its 65 isolated mountain ranges rising from low elevation desert to well over 2500 meters, the Madrean Archipelago supports up to eight biological communities that are ordered along elevational gradients—a phenomenon known as biome-stacking. As a result, the region contains an incredibly rich assortment of species. However, higher temperatures and aridity predicted under future climate change are expected to affect the region, with species in the uppermost biomes (i.e., conifer forests) being especially vulnerable. Species distribution models for multiple high-elevation taxa suggest that under 21st-century climate change, the Madrean Sky Islands will become increasingly isolated due to conifer forest habitat loss which may have negative consequences for the region’s cryptic diversity. MAXENT is a popular species distribution modelling program that uses presence-only data to estimate habitat suitability. Previous works have shown that MAXENT’s likelihood is identical to that of an inhomogeneous Poisson process (IPP) conditioned on the number of occurrence records. Consequently, MAXENT’s raw output may, under specific assumptions, be considered proportional to relative abundance. Using Arizona occurrence records for the mosquito (Diptera: Culicidae) Aedes aegypti (Linnaeus, 1762), a method is proposed that uses abundance data to rescale MAXENT’s raw output into an estimate of the probability of presence for a species. When the area of interest is environmentally heterogeneous and occurrence records are not equally distributed, as was the case for Arizona, it can be beneficial to divide the area into regions and then mosaic the resulting probability of presence maps.
    • Tailings Storage Facility (TSF) Stability and Water Management

      Kim, Kwangmin; Jeong, Yongsik; Kemeny, John M.; Tenorio, Victor Octavio; Son, Young-Jun (The University of Arizona., 2020)
      Tailings storage facilities (TSFs) are among the largest geotechnical structures in the world and operate for adequate and safe storage of tailings during and after mining activities. Ensuring the stability of these enormous structures has been a long-standing environmental liability for mining-related communities; the failures of TSFs can not only undermines the sustainable development of a mine, but also can cause irreparable hazards and damage to those communities and environments. This document presents research regarding three main topics related to TSFs water management. The first topic is development of site-specific guidelines for safe TSF water management. In this regard, the study focuses on determining the optimal beach distance from the decant pond to the crest, which can be a practical and easy monitoring criterion for securing TSF stability. 2D stress-seepage coupled analyses were conducted to evaluate geotechnical stability; additionally, water increments that increase due to unexpected weather conditions (heavy rainfall and strong wind) were considered for the optimal beach distance. The results of this research can be useful in developing a TSF risk level guideline of the testing site. The second topic is investigation of the potential of an environmentally-friendly polymer as a new drag reduction agent (DRA) to reduce frictional pressure loss and also to conserve water. Lab-scale pipe loop tests examined the effect of the polymer on the pressure loss of the tailings slurry in pipe flows. The experiment results confirmed the potential for using the polymer as a new DRA. Findings showed that pressure loss decreased with increasing polymer percentages up to 4%, but increased above concentrations of 4%. 3D numerical models of computational fluid dynamics (CFD) simulations were developed and validated based on the pipe loop test results. The model provided the potential amount of water and transportation energy saving with minimal changes of pressure loss, induced by solid concentration increases. The final topic deals with usage of the new DRA. When the DRA is employed and solids concentration is increased, the study explored the relevant operating issues, such as settling of tailings particles in pipelines, and accelerating pipeline wear using 3D CFD numerical simulations. The polymer used in the second study reported here was expected to improve the efficiency of tailings slurry flows in pipelines. The results confirmed that by employing the new DRA, the minimal changes of pressure loss levels could be achieved even though there were increases in solids concentration. The polymer also increased the flow velocity, making it possible to transport tailings faster than the critical velocity at which the particle settlement begins. Also, the addition of the polymer resulted in an increase of the erosion rate, due to increased flow velocity, but the total amount of erosion was reduced at certain solids concentrations.
    • Studying in China but in an English Program: Language Ideologies among Study Abroad Students in China in the Age of Belt and Road

      Diao, Wenhao; Wang, Yi; Warner, Chantelle; Zhang, Qing (The University of Arizona., 2020)
      As China’s signature policy to expand its global influence, the Belt and Road initiative (BRI) incorporates plans to drastically increase the number of international students to study in China. Following the BRI, a growing trend among Chinese institutions of higher education is to offer programs taught exclusively in English for study abroad students, many of whom are from non-Anglophone countries in Asia, Europe, and Africa. While this trend may seem to reflect neoliberal ideals that assume English to be the global language in the marketing of study abroad (Kubota, 2016a), it simultaneously presents an intriguing reality in the context of China, where the BRI itself is intended to expand China’s economic and cultural influence globally. By drawing from the theory of language ideology (e.g., Gal, 1989; Kroskrity, 2004, 2010), this dissertation investigates this phenomenon of study abroad in English programs in China against the backdrop of BRI. Defined as beliefs, feelings, and conceptions about language structure and use (Kroskrity, 2010), language ideology is a useful tool to understand how individuals negotiate language use vis-à-vis powerful social structures in specific contexts (Douglas Fir Group, 2016). In the case of study abroad, language ideologies can operate as organizing principles to recruit students and direct them toward certain destinations but not others (Park & Bae, 2009), and yet these ideologies may also become contested and negotiated in multilingual realities (De Costa, 2016). This dissertation focuses on study abroad students’ everyday academic, social, and professional life in China. The participants were thirty study abroad students and eight other stakeholders in a business program at a public university in Shanghai, China. Data were collected over the course of six months from questionnaires, 87-hour interviews, field notes from the classroom (213 class-hours) and participant observation, and artifacts. The findings here reveal perplexing and oftentimes contradictory language ideologies in institutional discourses and the students’ everyday practices. Due both to the linguistic segregation that separated them from local Chinese students, who were prohibited to enroll in English-only degree programs within China, and to these students’ own belief that English should be the international language, these students formed a so-called “foreign bubble” environment for both academic learning and social purposes. Yet their belief of English as an international language was immediately challenged by their perceived reality that Chinese people do not speak good English and that Chinese is necessary for living in China. In the professional domain, some of these students came to China with long term career goals and even hopes for immigration. However, employers stereotyped the English-only business program to be academically compromised and its students to be linguistically and professionally less qualified than their peers in China’s regular programs taught in Chinese. Meanwhile, those students in the program who were actually proficient in both English and Chinese were often hired to do simple language services (e.g., translating) (Heller & McElhinny, 2017) and represent the companies’ international image, rather than their specialization in business. These results show the coexistence of both neoliberal ideologies and another set of thinking that is associated with China’s rising power in the world. These findings not only add insights into the existing scholarship on the use of English in academic programs; but more importantly, they show inconsistencies in China’s language and education policies that sometimes promote the Chinese language as a tool to enhance China’s soft power abroad (Hubbert, 2019) but in other instances -- such as the case in this study -- the language is seen as an obstacle that needs to be removed in order to promote China’s influence.
    • Are Offspring-Heteromorphic Species Hedging Their Bets?

      Venable, David L.; Scholl, Joshua; Dlugosch, Katrina M.; Becerra, Judith X.; Sanderson, Michael J. (The University of Arizona., 2020)
      Most organisms have canalized the production of their offspring to one form or shape which is presumably best adapted for the environment they inhabit. Nevertheless, at least 500 species of plants, among other organisms, defy this general pattern and instead produce multiple, morphologically different seeds simultaneously. Researchers have proposed numerous drivers of this phenomenon. Theoretical work strongly suggests bet hedging as the major underlying mechanism and this has become a widely accepted but empirically untested assumption. At its core, seed heteromorphism can be attributed to only three underlying mechanisms or some integrated strategy among them: bet hedging, plasticity, and adaptive tracking. In this thesis I focus on empirically testing the long-standing assumption that seed heteromorphism serves as a bet hedging strategy. First, I take a broad perspective in summarizing the occurrence of seed heteromorphism in southwestern North America. Then I use this dataset to phylogenetically evaluate seed heteromorphism as a bet-hedging strategy across an unprecedented 96 seed-heteromorphic species from 51 genera and 9 angiosperm families. In so doing, I evaluate the pervasive, and to date empirically untested, assumption that the occurrence of seed heteromorphism is spatially associated with environmental unpredictability as measured, quantitatively, by aridity. This is the first study to statistically evaluate large-scale evidence for bet hedging among seed-heteromorphic species. Second, I narrow my focus and use field and experimental work to evaluate seed heteromorphism as a bet hedging strategy across multiple populations in a particularly tractable winter, desert annual species, Pectocarya heterocarpa (I.M. Johnston) I.M. Johnston (Boraginaceae). This species produces visually distinct and spatially separated seed morphs which allow for the assessment of phenotypic expression in reproductive investment and facilitate experimental manipulation. I couple my field collections with greenhouse studies to evaluate the role of plasticity in the expression of seed heteromorphism. I demonstrate that P. heterocarpa hedges its bets by plastically adjusting its ratio of low risk to high risk seed morphs across the aridity gradient in the direction predicted by bet hedging theory. I also show that seed germination fraction across the aridity gradient follows patterns expected from bet hedging with seeds from more variable sites displaying increased dormancy. Third, I focus even more locally on just one population of P. heterocarpa to quantify the fitness consequences of its different seed morphs across years, environmental conditions, and germination cohorts. Using a field and greenhouse experiment I evaluate how the natural germination timing of P. heterocarpa seed morphs translate to fitness differences across different rainfall regimes and years. Overall, I find evidence for bet hedging in that seed types never had significant average fitness differences across treatments, years, or germination cohorts, but instead exhibited complex interactions with these factors such that each seed type had highest fitness under different combinations of conditions. My results demonstrate that the different seed morphs of P. heterocarpa, by virtue of these fitness differences, act to reduce variance in fitness both within and across years as predicted by bet hedging theory. The assumption that offspring heteromorphism serves as a bet hedging strategy is pervasive in the literature despite the lack of rigorous empirical tests. In this dissertation I combine large- and narrow-scale analyses to present a rigorous analysis of bet hedging among offspring-polymorphic species. Overall, this work helps us gain a better understanding of how organisms cope with change, which is crucial for gaining any predictive power for population dynamics amidst global climate change.
    • High-Resolution Spectroscopy of Small Transient Species Containing Metals and Phosphorus: Applications to Fundamental Chemical Physics and Astrochemistry

      Ziurys, Lucy; Burton, Mark; Kukolich, Stephen G.; Lichtenberger, Dennis L.; Brown, Michael F. (The University of Arizona., 2020)
      Pure rotational spectroscopy is one of the highest resolution techniques available for studying gas-phase molecules and allows for understanding very weak, fundamental interactions within molecules. For radical species, the coupling of angular momenta is readily observed in their microwave spectra, which can be used to infer about the electronic state manifold, describe the intramolecular bonding, as well as guide theoretical models. Pure rotational spectroscopy is also the best technique for determining the structures and geometries of unsolvated molecules. Because of its sensitivity to isotopic differences, measurement in the millimeter-wave also provides rest frequencies for radio astronomical searches of astrophysically relevant molecules. Both direct absorption spectroscopy and Fourier transform microwave/millimeter-wave spectroscopy have been used to study the spectra of several transient molecules, including ZnBr, KO, CrP, SiP, ScC2, ClZnCH3, LiNH2, NaNH2, and CoS as well as several isotopic variations. The difficulty in measuring pure rotational spectra often stems from the synthesis of the molecule, for which three techniques were employed. These methods involve the laser ablation of metal rods, melting of pure metal in Broida-type ovens, and vaporization of organometallic precursors or phosphorus. The measured data were analyzed with effective Hamiltonians consisting of rotational, fine structure, hyperfine structure, and occasionally deperturbation terms. For some species, such as ZnBr, KO, CrP, and SiP, these results provide the first-ever high-resolution molecular parameters; for others, including LiNH2, NaNH2, and CoS, low-frequency measurements were made to establish additional hyperfine constants. Also, the structures of ScC2 and ClZnCH3 have been established through the non-trivial measurements of isotopically substituted versions.
    • Interplay Between Human Papillomavirus and cGAS/STING

      Campos, Samuel K.; Uhlorn, Brittany Leigh; Rogers, Gregory C.; Schenten, Dominik; Purdy, John G.; Goodrum Sterling, Felicia D. (The University of Arizona., 2020)
      The germline-encoded innate immune system is the human body’s initial defense system against foreign pathogens. Essential to this system are pattern recognition receptors (PRRs), which recognize pathogen-associated molecular patterns (PAMPs). A key PRR system, the cGAS/STING pathway, recognizes foreign DNA in the cytoplasm of a cell. Upon binding foreign DNA, cGAS creates second messenger 2’-3’-cGAMP which activates STING at the endoplasmic reticulum. Once activated, STING translocates to the Golgi, where it recruits the kinase TBK1 and transcription factor IRF3. TBK1 phosphorylates IRF3, enabling the transcription factor to translocate to the nucleus and induce the transcription of type-I interferon (IFN-I) genes. Mechanisms that regulate the cGAS/STING pathway are needed to ensure that an IFN-I response is mounted against only foreign or harmful material at the correct place and time. While cGAS typically only mounts a response to DNA in the cytoplasm of a cell, nuclear and cytoplasmic contents are mixed during mitosis, therefore giving cGAS access to genomic DNA. It is unknown whether cGAS mounts an IFN-I response to exogenous DNA during mitosis, and if not, what mechanisms are in place to ensure the pathway is inactive during cellular division. Human papillomavirus (HPV) causes one of the most commonly transmitted sexual infections and is attributed to nearly 5% of all human cancers. HPV infects the basal cells of differentiated cutaneous and mucosal epithelium. Work from our lab and others has shown that the viral genome hides within cellular organelles until the onset of mitosis. This trafficking mechanism is unique, but the evolutionary rationale for such vesicular, mitosis- dependent egress is unknown. Further, it is unknown how HPV evades detection during both initial infection and genome maintenance. Overall, we hypothesize that HPV evades detection by cGAS/STING during both initial infection and viral persistence to support the viral lifecycle. We speculate HPV uses a vesicular trafficking mechanism, carefully timed with mitosis when we propose cGAS/STING to be inactive, to evade detection during initial infection. Further, we hypothesize HPV antagonizes the cGAS/STING pathway during the genome maintenance phase. Using biochemical inhibitors and cell synchronization methods in a spontaneously immortalized cell line, we show that mitotic Golgi vesiculation attenuates cGAS/STING activity at the level of STING. Further, we use HPV pseudovirions to show that the virus evades detection by cGAS/STING. By alternatively delivering those virions via cationic liposomes, we show this evasion during initial infection is due to the virus’ vesicular, mitosis-dependent trafficking mechanism. Lastly, we show that persistent HPV18 infection in human foreskin keratinocytes suppresses IFN genes and further inhibits cGAS/STING responses to exogenous foreign DNA. Overall, this dissertation provides significant contributions to the fields of innate immunity and virology. Specifically, the findings herein provide insights into a novel regulatory mechanism of the innate immune system. Additionally, this work uncovers unique immunoevasive tactics that enable HPV to evade and antagonize the cGAS/STING system to achieve infection and viral persistence. Ultimately, understanding how HPV takes advantage of cGAS/STING regulation and further inhibits its function is essential to learning how HPV achieves viral persistence, as persistent infections cause cancer.
    • Disulfide-Masked Prochelators to Target the Iron Metabolism of Cancer: Coordination Chemistry and Antiproliferative Activity in Malignant Cells

      Tomat, Elisa; Utterback, Rachel; Lichtenberger, Dennis; Horton, Nancy; Miranda, Katrina (The University of Arizona., 2020)
      Iron is the most abundant transition metal found in the human body, and it is essential for many biological processes, including oxygen transport, cellular respiration and DNA synthesis. Cancer cells have an increased demand for iron due to their higher proliferation rates, and this characteristic makes cancer cells more susceptible to iron deprivation. Thus, iron chelators have been studied for their use as chemotherapeutics for the treatment of cancer. Chapter 1 of this dissertation provides a brief summary of the roles of iron in cancer, as well as an overview of the different types of iron chelators that have been studied for the treatment of cancer. Chapter 2 focuses on a prochelation approach to improve the intracellular delivery of thiosemicarbazone, semicarbazone, and aroylhydrazone chelators for cancer applications. Specifically, these prochelators use a disulfide switch to mask a thiolate iron binding moiety so that these compounds can be activated intracellularly. These compounds show antiproliferative activity in cultured breast cancer cells and result in the intracellular formation of iron complexes that are not redox active. Further cell-based assays demonstrated that these chelators cause cell cycle arrest at the G1/S interface and induce apoptosis in cells. Chapter 3 focuses on one of our most biologically active prochelators, (AH1-S)2, and the characterization of its iron (III) complexes. The chelator AH1-SH binds iron in a 2:1 ligand-to-metal ratio, and the resulting complex features a low-spin Fe(III) center. Unlike our cationic thiosemicarbazone Fe(III) complexes, the Fe(III) complex of AH1-SH is neutral due to the ability of the aroyl hydrazone ligand to exhibit keto-enol tautomerization. The X-ray structure of this complex shows the AH1 ligand bound to the iron(III) center both in the keto form and in the enolate form. Further studies by EPR demonstrate that different protonation states of this complex exist in acidic, neutral, and basic media.