Now showing items 1-20 of 76582

    • Brownian fluctuations of flame fronts with small random advection

      Henderson, Christopher; Souganidis, Panagiotis E.; Univ Arizona, Dept Math (WORLD SCIENTIFIC PUBL CO PTE LTD, 2020-06-10)
      We study the effect of small random advection in two models in turbulent combustion. Assuming that. the velocity field decorrelates sufficiently fast, we (i) identify the order of the fluctuations of the front with respect to the size of the advection; and (ii) characterize them by the solution of a Hamilton-Jacobi equation forced by white noise. In the simplest case, the result yields, for both models, a front with Brownian fluctuations of the same scale as the size of the advection. That the fluctuations are the same for both models is somewhat. surprising, in view of known differences between the two models.
    • Correlates of cognitive impairment in adult cancer survivors who have received chemotherapy and report cognitive problems

      Gutenkunst, Shannon L; Vardy, Janette L; Dhillon, Haryana M; Bell, Melanie L; Univ Arizona, Stat Grad Interdisciplinary Program; Univ Arizona, Mel & Enid Zuckerman Coll Publ Hlth, Dept Epidemiol & Biostat (SPRINGER, 2020-07-14)
      Objective Cognitive impairment negatively affects some cancer survivors who have completed chemotherapy; however, factors underlying this cognitive impairment remain poorly understood. We aimed to investigate (1) the relative importance of demographics, medical, and psychological characteristics associated with cognitive impairment and (2) the specific variables associated with cognitive impairment in adult cancer survivors who completed adjuvant chemotherapy. Methods We performed post hoc analyses of baseline data from early-stage cancer survivors with cognitive complaints who received adjuvant chemotherapy 0.5-5 years earlier and volunteered for a trial designed to improve cognition. The primary outcome of self-reported cognitive impairment was measured using a questionnaire; secondary outcome of objective cognitive impairment was measured using a computerized neuropsychological test battery. Hierarchical linear regression determined the relative importance of demographics, medical, and psychological characteristics in associations with both self-reported and objective cognitive impairment. Results The sample was 95% female and 89% breast cancer patients. The final model accounted for 33% of variation in self-reported cognitive impairment (n = 212, demographics 5%, medical 3%, and psychological 25%), with fatigue and stress as significant individual correlates (pvalues <= 0.0001). For the secondary analysis, the final model accounted for 19% of variation in objective cognitive impairment (n = 206, demographics 10%, medical 5%, and psychological 4%), with age, smoking history, and number of chemotherapy cycles as significant individual correlates. Conclusion We found that psychological characteristics are more important than demographic and medical characteristics in self-reported cognitive impairment, whereas other characteristics are more important in objective cognitive impairment. This suggests clinicians should investigate possible psychological problems in cancer survivors who self-report cognitive impairment.
    • ‘Personality in Its Natural Habitat’ Revisited: A Pooled, Multi‐sample Examination of the Relationships Between the Big Five Personality Traits and Daily Behaviour and Language Use

      Tackman, Allison M.; Baranski, Erica N.; Danvers, Alexander F.; SBARRA, DAVID A.; Raison, Charles L.; Moseley, Suzanne A.; Polsinelli, Angelina J.; Mehl, Matthias R.; Univ Arizona, Dept Psychol (WILEY, 2020-07-16)
      Past research using the Electronically Activated Recorder (EAR), an observational ambulatory assessment method for the real-world measurement of daily behaviour, has identified several behavioural manifestations of the Big Five domains in a small college sample (N = 96). With the use of a larger and more diverse sample of pooled data from N = 462 participants from a total of four community samples who wore the EAR from 2 to 6 days, the primary purpose of the present study was to obtain more precise and generalizable effect estimates of the Big Five-behaviour relationships and to re-examine the degree to which these relationships are gender specific. In an extension of the original article, the secondary purpose of the present study was to examine if the Big Five-behaviour relationships differed across two facets of each Big Five domain. Overall, while several of the behavioural manifestations of the Big Five were generally consistent with the trait definitions (replicating some findings from the original article), we found little evidence of gender differences (not replicating a basic finding from the original article). Unique to the present study, the Big Five-behaviour relationships were not always comparable across the two facets of each Big Five domain. (C) 2020 European Association of Personality Psychology
    • Conformal perturbation theory for twisted fields

      Keller, Christoph A; Zadeh, Ida G; Univ Arizona, Dept Math (IOP PUBLISHING LTD, 2020-03-06)
      We investigate second order conformal perturbation theory for Z(2) orbifolds of conformal field theories in two dimensions. To evaluate the necessary twisted sector correlation functions and their integrals, we map them from the sphere to its torus double cover. We discuss how this relates crossing symmetry to the modular group, and introduce a regularization scheme on the cover that allows to evaluate the integrals numerically. These methods do not require supersymmetry. As an application, we show that in the torus orbifold of 8 and 16 free bosons, Z(2) twist fields are marginal at first order, but stop being marginal at second order.
    • Flat bands in twisted bilayer transition metal dichalcogenides

      Zhang, Zhiming; Wang, Yimeng; Watanabe, Kenji; Taniguchi, Takashi; Ueno, Keiji; Tutuc, Emanuel; LeRoy, Brian J.; Univ Arizona, Dept Phys (NATURE PUBLISHING GROUP, 2020-07-06)
      Using scanning tunnelling spectroscopy, the flat bands in twisted bilayer WSe(2)are shown near both 0 degrees and 60 degrees twist angles. The crystal structure of a material creates a periodic potential that electrons move through giving rise to its electronic band structure. When two-dimensional materials are stacked, the resulting moire pattern introduces an additional periodicity so that the twist angle between the layers becomes an extra degree of freedom for the resulting heterostructure. As this angle changes, the electronic band structure is modified leading to the possibility of flat bands with localized states and enhanced electronic correlations(1-6). In transition metal dichalcogenides, flat bands have been theoretically predicted to occur for long moire wavelengths over a range of twist angles around 0 degrees and 60 degrees (ref.(4)) giving much wider versatility than magic-angle twisted bilayer graphene. Here, we show the existence of a flat band in the electronic structure of 3 degrees and 57.5 degrees twisted bilayer WSe(2)samples using scanning tunnelling spectroscopy. Our direct spatial mapping of wavefunctions at the flat-band energy show that the localization of the flat bands is different for 3 degrees and 57.5 degrees, in agreement with first-principles density functional theory calculations(4).
    • Superiority of Bayes estimators over the MLE in high dimensional multinomial models and its implication for nonparametric Bayes theory

      Bhattacharya, Rabi; Oliver, Rachel; Univ Arizona, Dept Math (ELSEVIER, 2020-10)
      The performance of Bayes estimators is examined, in comparison with the MLE, in multinomial models with a relatively large number of cells. The prior for the Bayes estimator is taken to be the conjugate Dirichlet, i.e., the multivariate Beta, with exchangeable distributions over the coordinates, including the non-informative uniform distribution. The choice of the multinomial is motivated by its many applications in business and industry, but also by its use in providing a simple nonparametric estimator of an unknown distribution. It is striking that the Bayes procedure outperforms the asymptotically efficient MLE over most of the parameter spaces for even moderately large dimensional parameter spaces and rather large sample sizes. (C) 2020 Elsevier B.V. All rights reserved.
    • Immunoglobulin A vasculitis associated with inflammatory bowel disease: a retrospective cohort study

      Villatoro-Villar, M; Crowson, C S; Warrington, K J; Makol, A; Koster, M J; Univ Arizona, Div Rheumatol, Arthrit Ctr (TAYLOR & FRANCIS LTD, 2020-05-27)
      Objective To describe the baseline characteristics and outcome of a series of patients with inflammatory bowel disease (IBD) and immunoglobulin A vasculitis (IgAV). Method Patients with biopsy-proven IgAV with IBD were identified retrospectively. Data were abstracted from direct medical chart review. Each IBD-IgAV case was matched to two controls with IgAV but without IBD. Results Nine patients were identified (seven Crohn's disease, two ulcerative colitis). Mean length of time between IBD diagnosis and IgAV onset was 17.3 +/- 19.9 years. For patients on biologic treatment for IBD, mean length of time between biologic initiation and IgAV onset was 3.3 +/- 3.8 years. Active IBD at IgAV onset was present in 56%. Tumour necrosis factor inhibitors (TNFi) were used for IBD in 89%. At IgAV onset, six patients were on treatment with TNFi; one subsequently discontinued, two switched to another TNFi, and three continued. At the last follow-up, three of five patients who remained on TNFi had full resolution of IgAV despite ongoing TNFi use. No differences were seen between cases with IBD IgAV and matched non-IBD-IgAV controls regarding development of end-stage renal disease, resolution of haematuria or proteinuria, and time to complete IgAV response. Conclusion Baseline characteristics and outcomes of patients with IBD-IgAV are similar to those with IgAV without IBD. Development of IgAV is not limited to patients with clinically active IBD. Whether TNFi use is related to the pathogenesis of IgAV in some patients with IBD remains unclear. Further research into pathophysiological connections between IBD and IgAV is needed.
    • Security symptoms

      Meyer, Dugan; Univ Arizona, Sch Geog & Dev (SAGE Publications, 2020)
      Gentrification is a security project. Though this claim is not new, existing scholarship on contemporary urban (in)security in the Global North, especially in the context of gentrification, has often struggled with a particular problem: how to account for the decidedly ambivalent character of securitization. Familiar frameworks like ‘revanchism’ and ‘fear of crime’ have proven insufficient alone to explain the seemingly paradoxical investment in insecurity that animates the security paradigm. In this article, I consider how psychoanalytic theory might be mobilized for a libidinal geography of urban (in)security, an approach that would focus less on the phantasmagoric referents against which society supposedly needs protection and more on the libidinal investments through which these referents are (re)produced and administered in order to cohere, sustain and naturalize a social and spatial order rooted in dispossession. Drawing on Lacanian articulations of fantasy, drive, jouissance and symptom and applying these concepts to a consideration of contemporary anti-gang policing in the United States, I demonstrate how ambivalence and ontological incoherence function not as evidence of security’s limits but rather as liberal social order’s very condition of possibility.
    • Amplification of waves from a rotating body

      Cromb, Marion; Gibson, Graham M.; Toninelli, Ermes; Padgett, Miles J.; Wright, Ewan M.; Faccio, Daniele; Univ Arizona, Wyant Coll Opt Sci (NATURE PUBLISHING GROUP, 2020-06-22)
      Acoustic waves that carry orbital angular momentum are amplified as they pass through an absorbing disk when the rotation rate exceeds the frequency of the incident wave, thus providing an experimental demonstration of Zel'dovich amplification. In 1971, Zel'dovich predicted that quantum fluctuations and classical waves reflected from a rotating absorbing cylinder will gain energy and be amplified. This concept, which is a key step towards the understanding that black holes may amplify quantum fluctuations, has not been verified experimentally owing to the challenging experimental requirement that the cylinder rotation rate must be larger than the incoming wave frequency. Here, we demonstrate experimentally that these conditions can be satisfied with acoustic waves. We show that low-frequency acoustic modes with orbital angular momentum are transmitted through an absorbing rotating disk and amplified by up to 30% or more when the disk rotation rate satisfies the Zel'dovich condition. These experiments address an outstanding problem in fundamental physics and have implications for future research into the extraction of energy from rotating systems.
    • Label-free Mie Scattering Identification of Tumor Tissue Using an Angular Photodiode Array

      Bills, Matthew V; Yoon, Jeong-Yeol; Univ Arizona, Dept Biomed Engn (IEEE, 2020)
      Tumors differ from normal tissues in several meaningful ways, including cellular size, morphology, and protein expression, which will accordingly change the refractive index and the size/morphology of cells. There are also important differences in the tissue organization and unique tissue-specific cell densities. Instead of the time-consuming and labor-intensive histology involving the use of a benchtop microscope, a plot of Mie scattering intensities at a fixed wavelength against the scattering angle, which we referred to as “Mie spectrum,” is suggested as an alternative to identify a tumor from normal tissues. An angular photodiode array is developed to measure this Mie spectrum with three different light-emitting diodes (blue, green, and red) as light sources. The resulting Mie spectra show the characteristic peaks for the rat colonic tissues, and substantial differences can be found between the tumor and normal tissues. Two peaks were identified at 120° and 150° scattering angles, potentially representing the capillaries and colon cells, respectively. Contributions from crypts and goblet cells, represented by the scattering at 140°, were minimal. Substantial differences between the tumor and normal tissues were found with 45°–70° light irradiation angles.
    • Aluminum nanocomposites reinforced with monolayer polyaniline (C3N): assessing the mechanical and ballistic properties

      Eshkalak, Kasra Einalipour; Sadeghzadeh, Sadegh; Molaei, Fatemeh; Univ Arizona, Dept Min & Geol Engn (ROYAL SOC CHEMISTRY, 2020-05-25)
      This study unveils C3N, a new material that serves as an excellent reinforcement to enhance the mechanical properties of aluminum using a molecular dynamics simulation method. Results show that the C3N nanosheets greatly improve the mechanical properties of aluminum-based nanocomposites. With only 1.3 wt% C3N, the Young's modulus, fracture strength, and fracture strain increased by 27, 70, and 51 percent, respectively. A comparison between the reinforcement of graphene and C3N in an aluminum (Al) matrix shows that in terms of the mechanical properties, the graphene-aluminum composite is weaker than the C3N-aluminum composite in the tensile tests, but slightly stronger in the energy adsorption tests. Our findings show that the mechanical properties are highly dependent on the strain rate and temperature. The effects of various imperfections, such as the vacancy, crack, and void defects, on the mechanical properties were also studied. Results show that in the presence of void defects, the structure exhibited higher mechanical properties than when there were other defects. This phenomenon was found to be related to the decrease in the effective load transfer from aluminum to C3N. Furthermore, by increasing the weight percent of the nanosheets up to 5%, the energy absorption rate increased by 25% compared to the pure aluminum. When C3N was placed on top of the aluminum surface, the silicon nanoparticles were associated with a 35% energy adsorption by the nanocomposite. The results of this paper could be used to help understand and overcome some limitations in the fabrication of metallic nanocomposites with 2D material reinforcement.
    • Optimal damping coefficient for a class of continuous contact models

      Poursina, Mohammad; Nikravesh, Parviz E.; Univ Arizona, Dept Aerosp & Mech Engn (SPRINGER, 2020-06-03)
      In this study, we develop an analytical formula to approximate the damping coefficient as a function of the coefficient of restitution for a class of continuous contact models. The contact force is generated by a logical point-to-point force element consisting of a linear damper connected in parallel to a spring with Hertz force-penetration characteristic, while the exponent of deformation of the Hertz spring can vary between one and two. In this nonlinear model, it is assumed that the bodies start to separate when the contact force becomes zero. After separation, either the restitution continues or a permanent penetration is achieved. Therefore, this model is capable of addressing a wide range of impact problems. Herein, we apply an optimization strategy on the solution of the equations governing the dynamics of the penetration, ensuring that the desired restitution is reproduced at the time of separation. Furthermore, based on the results of the optimization process along with analytical investigations, the resulting optimal damping coefficient is analytically expressed at the time of impact in terms of system properties such as the effective mass, penetration velocity just before the impact, coefficient of restitution, and the characteristics of the Hertz spring model.
    • Parental Financial Education During Childhood and Financial Behaviors of Emerging Adults

      LeBaron, Ashley B.; Holmes, Erin K.; Jorgensen, Bryce L.; Bean, Roy A.; Univ Arizona, Family Studies & Human Dev, Norton Sch Family & Consumer Sci (SPRINGER PUBLISHING CO, 2020-03-16)
      The purpose of this article was to determine whether overt financial education from parents during childhood (retrospective measure collected in the same survey wave) is associated with a greater frequency of healthy financial management behaviors in emerging adulthood, and whether this relationship is dependent on gender Using a sample of emerging adults from the Flourishing Families dataset (N = 437), we ran two multivariate linear regressions one with and one without the interaction variable. Results suggest that financial education from parents during childhood is linked with a greater frequency of healthy financial behaviors in emerging adulthood but was not dependent on gender Financial educators should involve parents when teaching children about money, and they should educate parents on how to teach their children about money.
    • Migrant Itinerancy: The Hemispheric Politics of Contemporary Undocumented Migration

      Acosta, Abraham; Bejar Lara, Adolfo; Murphy, Kaitlin; Huizar-Hernandez, Anita; Morales, Monica (The University of Arizona., 2020)
      Migrant Itinerancy: The Hemispheric Politics of Contemporary Undocumented Migration analyzes contemporary literary production on the recent intensification of migration patterns in Latin America and the United States. I engage with Latin American and Chicano cultural criticism to examine the neoliberal re-structuration of the nation-state under neoliberalism and its effects on the politics of migration in the region. Migrant Itinerancy argues that undocumented migration exposes the unfounded nature of any figuration of community and reveals the exclusionary logics of contemporary discourses of resistance. I propose the concept of migrant itinerancy as a method of analysis to highlight tensions that reveal how undocumented migration problematizes forms of political subjectivity premised upon notions of identity and belonging. Rather than merely reflecting on the effects of the exclusionary logics of immigration discourse in the region, Migrant Itinerancy asks how the tensions and contradictions at the heart of the politics of migration in the hemisphere open a space of reflection to rearticulate a sense of community premised upon practices of communal care. Through readings of Antonio Ortuño’s La fila india, Luis Alberto Urrea’s The Devil’s Highway, Óscar Martínez’s The Beast, and Valeria Luiselli’s Los niños perdidos, I demonstrate how undocumented migration disrupts residual postcolonial configurations of power, emerging as a political force that demands the redrawing of our current social order. By foregrounding questions of identity, national belonging, human rights, immigration and asylum discourse in a hemispheric context, Migrant Itinerancy reassess the status of the nation-state as principle of social and political organization in times of global migrations.
    • Corporations and Shareholder Political Transparency Activism in the United States

      Earl, Jennifer; Galaskiewicz, Joseph; Zhang, Yongjun; Breiger, Ronald; Fiel, Jeremy (The University of Arizona., 2020)
      Scholars from sociology, political science, management, and economics have long debated the causes and consequences of business in politics. The controversy of corporate money in politics was amplified by the Supreme Court’s landmark 2010 Citizens United decision on electioneering communications. Policymakers, the public, and activists are worried that this might open the corporate campaign spending floodgates, and corporate America may abuse its political power over democracy. Many concerned primary and secondary stakeholders have tried to advocate for corporate political transparency and accountability. This dissertation examines the antecedents and consequences of primary shareholder activists that seek to improve corporate political transparency in the United States from 2000-2018. Using big data and web-scraping techniques, this dissertation offers several large-scale, novel datasets on U.S. public firms and addresses how shareholder activists select corporate targets, how corporate elites manage shareholder threats, and whether shareholder activists can disrupt corporate financial and political outcomes. Integrating both social movements and organizational theories, this dissertation shows that shareholder activists target corporate political activities not only because of managers not maximizing shareholder value but also due to the co-existence of corporate opportunities and threats that motivate activists promoting liberal causes. Corporate elites’ political ideology serves as a critical component that drives the emergence of shareholder political transparency activism. This dissertation also reveals that corporate elites tend to use multiple tactics such as political disclosure, board oversight, and policy reform to manage the challenges associated with potential or actual shareholder threats. This dissertation also demonstrates that shareholder activism can disrupt corporate political activities, but not financial outcomes.
    • She Works Hard for No Money: Understanding Women's Participation in Multi-Level Marketing Organizations

      Roth, Louise M.; Frederico, Krista Marie; Abramson, Corey; Leahey, Erin E. (The University of Arizona., 2020)
      Over 13 million U.S. women participate in the controversial multi-level marketing (MLM) industry. Advocates claim that the $36 billion industry provides flexible work opportunities for individuals interested in selling reputable consumer products as a licensed distributor within a sales network. Critics, including the U.S. Federal Trade Commission, warn that these companies often have convoluted compensation structures designed to enrich only those at the top of the pyramid-shaped recruitment scheme. With hefty required expenses of overpriced products to maintain an active distributorship, over three-quarters of sellers fail to turn a profit and most report either breaking even or losing money. Given these odds, why do women join an MLM? And why do women stay involved long-term, even if they fail to reach their expected earnings goals? Drawing on participant observation, as well as 59 in-depth interviews with women affiliated with one of three fictionally-named focal MLMs (DermaDynamix, BeautifOil, and Cute Couture), this dissertation illuminates the impressive hard work—and dismaying lack of compensation—for women enrolled as sellers in the highly stigmatized MLM industry. In particular, this study explores the contradictory expectations faced in motherhood: the cultural ideals of “stay-at-home” motherhood, but also the need and desire of many women to generate an income and have career fulfillment, all in a neoliberal context of minimal governmental supports for families (e.g., paid parental leave and low cost child care) and protections against victimization by predatory organizations (e.g., punitive action against deceptive practices by MLMs). To straddle the cultural contradictions within motherhood, these MLM selling women intentionally brought paid work into the home, but then often endeavored to separate their paid work from their household work through various boundary work. For example, rather than work a simultaneous shift, or perform both care work and MLM work at the same time, 76.2% of mothers of young children reported using a temporal boundary of a “sleep shift” to meet their MLM work requirements once children were asleep. This gave them the opportunity to appear to be stay-at-home mothers while still pursuing MLM work, yet this exacted a toll on their sleep and self-care. Using a panel design, consisting of one interview within an average of just over two months since joining an MLM, then a second interview at approximately one year after joining, I found that none of the women reached their expected earnings. Women in the two focal MLMs with a less burdensome investment ($1,500 or less) earned $1.71 per hour, while women with much greater investment requirements of nearly $7,000 earned $10.36 per hour. The high upfront cost in one and the low earnings in the other left all women struggling for any realized earnings beyond their initial investment, leading 44.44% of women to leave the MLM by their second interview. To entice women to remain involved despite both the unmet earnings and unanticipated costs, organizations deployed neoliberal positivity messages, or messages that merge the free-enterprise, low-governmental-regulation emphasis on workers themselves to secure their own employment actualization with the self-help optimism of positive psychology. Women differentially drew upon these same frames in explaining their own behavior within the MLM, with upper-income women more likely to prioritize their personal development and reject responsibility for their failure, and lower-income women more likely to internalize and attribute self-blame to their lack of success. This study concludes that women, especially mothers, are highly interested in reliable and well-paid work-from-home opportunities. As more companies recognize women’s interest in flexible time and work-from-home arrangements, and harness available technologies to offer these options, they will marshal a determined and productive work force—much to their mutual advantage. Further, they may turn the tide away from the alluring, ephemeral promises of the MLM industry, finally delivering a decisive blow to largely unregulated “product-based pyramid schemes” in favor of dependable, well-paid, flexible work.
    • Remaking Collective Identities: Statistical Statecraft, Indigenous Erasure, and Tribal Citizenship

      Cornell, Stephen; Leahey, Erin; Small-Rodriguez, Desi; Martinez, Daniel E.; Zavisca, Jane (The University of Arizona., 2020)
      In the social sciences, the identification of a population of interest is central to any research, policy, or program. Defining, counting, and classifying populations, however, are not objective. Rather, they are catalyzed by boundary making processes that are deeply embedded in social and political structures. In the United States (US), population classification and enumeration have long served the aims of American statecraft while disenfranchising certain populations. Racial and ethnic minorities, for example, share historical legacies of statecraft determining whose bodies are counted, whose views are official, and which knowledge corpora are privileged. As US demographics shift toward a majority minority population, there is growing need to understand the nature of boundary change, particularly with regard to intraracial heterogeneity and the intersection of citizenship and race. I use the case of American Indians and Alaska Natives (AIANs) to examine how the race-making and nation-making instruments of statecraft control the boundaries of indigeneity and threaten the sustainability of tribal populations. The AIAN case provides broad insight into how the American settler colonial ideology of erasure is reproduced in population statistics and how it can be challenged by marginalized populations who are rapidly becoming the majority in the US. I situate this inquiry within several bodies of literature, including the sociology of race and ethnicity, social stratification, state formation, and critical demography. While prior research on these topics has rarely examined the AIAN population, AIANs are an unusually rich case for analysis due to their concurrent straddling of race, ethnicity, and nationality boundaries. By centering tribal sovereignty, I demonstrate how the ongoing colonial realities of Native nations reflect the dialectical relationship between statecraft and AIAN population statistics. Drawing on an original database of tribal citizenship criteria, US Census data, and a tribal case study, I explore two central research questions. First, how have the data practices of colonial statecraft been utilized to construct and control Indigenous Peoples in the US? Second, how are Native nations reclaiming some measure of control over these data practices to reconstruct their group boundaries? I answer these research questions in three empirical studies that explore the nuances of tribal enumeration and classification. In the first study, I delve into the US Census as the official statistics context to explore how the federal government’s data collection efforts both challenge and support the sovereignty of Native nations. I find the intersection of census self-identification and tribal sovereignty problematic with implications for the utility of official US data on tribal populations. In the second study, I examine the racialization of tribal identity in a cross-national context by analyzing variation in tribal citizenship criteria. Using original data from more than 80 percent of Native nations in the contiguous US, I find that tribal blood quantum persists as a durable boundary of colonial control. In the third study, I focus on the nation state context by partnering with a Native nation to evaluate the extent to which blood quantum policy and demographic realities threaten the sustainability of tribal populations. This final study advances the case for more research in tribal demography to support Indigenous futures. As a whole, this dissertation reveals that the data practices of settler statecraft retain a strong hold on the collective boundaries of AIAN identity and that Native nations have various degrees of control over these boundaries depending on the context. I posit that the colonial imperative of Indigenous erasure is antithetical to the sustainability of tribal peoples and tribal sovereignty. Ultimately, to prevent erasure, Native nations must reclaim their boundaries of belonging.
    • Use of Advanced Microbiological Tools to Assess Surface Waters Used for Produce Production in Arizona Coupled with Innovative Outreach and Education

      Rock, Channah; McLain, Jean; Joe-Gaddy, Valerisa; Gerba, Charles; Cooper, Kerry (The University of Arizona., 2020)
      Background: The need for new pathogen testing methods and for individualized food and water safety curricula are becoming more evident, based on the number of outbreaks in the last decade. Water quality standards are continuously evolving, from shifts in monitoring regulations to increases in approved testing methods, it can be difficult for water professionals to stay abreast of current standards. This dissertation will highlight several primary issues, and will examine possible resolutions, for current concerns related to food and water safety in Arizona, US. Though Arizona is located in the arid Southwestern US, the state is a primary producer of leafy greens and other fresh produce and as such, it is a strong location for the work described herein. Study Aims: The following research and case studies aim to: (1) Establish the utility of a novel indicator organism, Bacteroides sp. to correlate with pathogen presence in agricultural irrigation water samples collected in Southern Arizona; (2) Explore the use of a cutting-edge molecular technology, droplet digital Polymerase Chain Reaction (ddPCR), for accurate analysis of environmental samples, using laboratory experimentation and a review of current literature; and (3) Develop and deliver an innovative food safety and water quality curriculum based on the Food Safety Modernization Act Produce Safety Rule (PSR), that will meet the unique needs of American Indian farmers in Arizona and New Mexico. Methods: Aim (1) focused on comparing concentrations of the currently regulated indicator organism, Escherichia coli (E. coli) to a novel indicator Bacteroides sp. to ascertain whether the novel indicator could overcome some of the known deficiencies related to generic E. coli. Irrigation water samples (n=98) were collected from Southern Arizona farms and analyzed for both indicators at the University of Arizona in Tucson. A comprehensive dataset was collected using several methods, including Real-Time Polymerase Chain Reaction (RT-qPCR), IDEXX Colilert® enzyme substrate technology, bacterial culturing techniques, and field analyses. Data from RT-qPCR (Bacteroides sp.) was compared to Colilert® results (generic E. coli) to evaluate any relationship between the two data sets, while both methods were also compared to bacterial molecular results for pathogen (E. coli O157:H7 and STEC and Salmonella) presence. Aim (2) examined the innovative technology ddPCR using recent published studies across multiple disciplines to evaluate its effectiveness for use in environmental samples on eDNA. Ultimately, a set of considerations were developed for analysis of environmental DNA samples. Lastly, Aim (3) developed a food safety and water quality curriculum based on American Indian cultural narratives using Universal Learning Design methodologies. The curriculum was successfully utilized in three trainings across Arizona and New Mexico for American Indian communities. Qualitative analysis of participant feedback was used to determine the effectiveness of the trainings and key learnings. Results: Aim (1) data suggests that Bacteroides sp., performed equally to generic E. coli in assessing water quality, but not to the extent of proposing Bacteroides sp., as a new indicator. The data did show that generic E. coli is an unsuitable fecal indicator organism, due to an 80.6% false negative rate; furthermore, neither indicator, generic E. coli or Bacteroides sp., correlated with pathogen presence. Thus, the search for other bacteria species for accurate water quality analysis continues. Aim (2) identified areas of environmental research in which ddPCR may be useful, such as marine research. However, the larger dynamic scale of RT-qPCR compared to ddPCR indicates that RT-qPCR would be the preferred method for accurate and reproducible results. Additionally, the cost of ddPCR is greater than RT-qPCR. Lastly, the classes conducted to realize Aim (3) were deemed successful by the surveys conducted and the positive feedback provided by participants. Discussion: The multi-project approach addresses three unique research and extension efforts under the main overarching question: How can water quality evaluation strategies and education in Arizona be improved to aid in the protection of public health? All three aims identified gaps in assessment of food safety and water quality in Arizona. The outstanding false negative rate found using approved methodology for E. coli found in Aim (1) suggests that the current water quality monitoring method is not accurate and this not protective of public health. This finding is supported by recent foodborne outbreaks in the US that may be related to agricultural irrigation water quality. Aim (2) showed that, although ddPCR does provide absolute quantification, the expense of the equipment and reagents as well as the confounding of data due to the complex nature of environmental samples are problematic. Thus, using RT-qPCR in lieu of ddPCR will provide similar, or even improved, results for a fraction of the cost. Aim (3) confirmed, through the development of culturally appropriate materials and deployment of trainings to AI participants, that inclusion of tribal producers though all steps is critical to the development of food safety guidelines that will be useful to all sectors of agricultural producers. By not including tribal produces into the conversation, critical perspectives about agriculture and culture are lost. While this work only touches the surface of the inclusion of tribal growers to the development of governmental regulations, it brings attention to the unique perspectives and traditions that indigenous cultures bring to the conversation.
    • Up Against an (Imaginary) Wall? Economic Insecurity and the White Working-Class in Contemporary America

      Galaskiewicz, Joseph; Kenworthy, Lane; Bjorklund, Eric; Leahey, Erin; Carlson, Jennifer (The University of Arizona., 2020)
      Economic insecurity has grown in the United States since the 1970s. This reflects extensive structural change across key social institutions, like the market, family, and the state. The experience and impact of rising insecurity has fallen disproportionately on the working-class (i.e., those without a four-year college degree). This includes previously insulated members of the working-class, like white non-Hispanics and men. Thus, for much of the white working-class the last fifty years has been a scenario of relative decline. The social, cultural, and economic position of the white working-class—relative to its peers—has generated a potentially distinct set of responses across multiple dimensions. This analysis focuses on two possible ramifications of white working-class economic insecurity: deaths of despair (suicide, drug overdose, alcohol) and reactionary politics. Using a combination of linear modeling and in-depth interviews I assess the relationship between economic insecurity, class position, deaths of despair, and reactionary politics in contemporary America. This research builds up theories of economics and health, class politics, and social inequality. It also provides insight into two highly topical events in modern America: rising deaths of despair and the (re)emergence of white reactionary politics.
    • Social Semiotics and Literacy: How Refugee-Background Adult Second Language Learners With Emerging Literacy Make Meaning in Multimodal Assessment Texts

      Warner, Chantelle; Altherr Flores, Jenna Ann; Fielder, Grace; Gilmore, Perry (The University of Arizona., 2020)
      This dissertation contributes to the fields of applied linguistics and literacy studies by considering the complex meaning-making processes of adults from refugee backgrounds as they navigate new textual, linguistic, and educational landscapes. Meaning-making as it is understood here involves both perception and production; it is inherently dialogical, and bound in social semiotic systems, which are not only linguistic but multimodal (Kress, 1994). Making meaning from multimodal texts requires understanding headings, directions, images, graphic devices, top/down and left/right organization, and the relationships among such elements. Taking these complications as a starting point, this research focuses on refugee-background adult second language learners, specifically, those with emerging literacy or who (have) experienced interruptions in their formal, school- based education. Such learners are becoming literate while simultaneously learning the language their literacy is developing in. For these reasons, the texts that are central to their experiences as learners of a new language – particularly language and literacy assessments – are of considerable importance for understanding the intersecting dimensions at play when people learn how to make meaning in a new language. While there is a growing body of research that has examined the psycholinguistic aspects of adult second language learners’ literacy development (e.g., Kurvers, 2002; Tarone et al., 2009; Young-Scholten & Naeb, 2010), many questions remain about the social semiotics of literacy – the interplay of context, culture, history, text, and meaning-making – for adults with emerging literacy or interruptions in their education. Moreover, little research to-date investigates the connections between social semiotics and the visual and multimodal literacies of this population (Altherr Flores, 2017; Bruski, 2012; Whiteside, 2008). This is problematical because many materials designed for beginning second language learners rely heavily on visual cues; without a comprehensive understanding of how such cues are being interpreted, the field’s understanding of how diverse populations make meaning from multimodal texts is compromised. Such knowledge is crucial for designing tests and other materials that aim to support learning. Building on prior scholarship, including an earlier pilot study by the author (Altherr Flores, 2017), this dissertation focuses on the role of visual literacy, language, and lived experience in multimodal texts that are used with adult second language learners with emerging literacy or interrupted education backgrounds. The core data for this research were: 1) English language and English literacy assessments – both in-house assessments used by a local program, and two experimental versions of assessments, created through iterative design as part of the research, 2) textual artifacts, and 3) semi-structured interviews with participants enrolled in community language and literacy classes. The analyses use a critical multimodal social semiotic approach (Kress, 2010; Kress & van Leeuwen, 2006; Pennycook, 2001) to examine the underlying assumptions presented in key texts’ visual and linguistic design, and investigate how this population understands and engages with these multimodal texts. The findings showed assumptions of multimodal design and visual literacy, and assumed content and referential background schemata in the design of the original assessment texts. In particular, the study exposed tensions between participants’ responses to textual and visual prompts and the expectations of test designers. The interview data further revealed the self-articulated strategies participants use to make meaning in multimodal texts, often relying on their lived experiences. By approaching the participants’ meaning-making practices as creative and complex, the research was able to show that the participants often relied on multimodal aspects of the test design that were taken for granted by the test designers. The participants often drew from their lived experiences, and also approached the assessments as a dialogue with the instructor, thus bringing shared frames of reference into play that would potentially be missed by an external evaluator. This study provides insight into how beginning language and literacy learners from refugee backgrounds make meaning from the verbal and visual aspects of assessment materials, and demonstrates how both textual composition and assessment practices may be inadvertently biased against individuals with vastly different literacy experiences. In addition to potentially helping test and materials developers to rethink their design choices, this study expands understandings of what it means to be literate by laying bare the creative and multimodal dimensions of engagement with even the most quotidian types of texts. The study’s results are beneficial for multimodal materials development and assessment practices in learning environments. The results also highlight sociopolitical issues in assessment of this population, and raise questions to be considered concerning assessment in higher stakes environments such as the U.S. naturalization test.