Now showing items 29294-29313 of 39117

    • The R Chondrite Record of Volatile-Rich Environments in the Early Solar System

      Lauretta, Dante S.; Miller, Kelly E.; Lauretta, Dante S.; Connolly, Harold C., Jr.; Zega, Thomas J.; Pascucci, Ilaria; Downs, Robert T.; Swindle, Timothy D. (The University of Arizona., 2016)
      Chondritic meteorites are undifferentiated fragments of asteroids that contain the oldest solids formed in our Solar System. Their primitive, solar-like chemical compositions indicate that they experienced very little processing following accretion to their parent bodies. As such, they retain the best records of chemical and physical processes active in the protoplanetary disk during planet formation. Chondritic meteorites are depleted relative to the sun in volatile elements such as S and O. In addition to being important components of organic material, these elements exert a strong influence on the behavior of other more refractory species and the composition of planets. Understanding their distribution is therefore of key interest to the scientific community. While the bulk abundance of volatile elements in solid phases present in meteorites is below solar values, some meteorites record volatile-rich gas phases. The Rumuruti (R) chondrites record environments rich in both S and O, making them ideal probes for volatile enhancement in the early Solar System. Disentangling the effects of parent-body processing on pre-accretionary signatures requires unequilibrated meteorite samples. These samples are rare in the R chondrites. Here, I report analyses of unequilibrated clasts in two thin sections from the same meteorite, PRE 95404 (R3.2 to R4). Data include high resolution element maps, EMP chemical analyses from silicate, sulfide, phosphate, and spinel phases, SIMS oxygen isotope ratios of chondrules, and electron diffraction patterns from Cu-bearing phases. Oxygen isotope ratios and chondrule fO2 levels are consistent with type II chondrules in LL chondrites. Chondrule-sized, rounded sulfide nodules are ubiquitous in both thin sections. There are multiple instances of sulfide-silicate relationships that are petrologically similar to compound chondrules, suggesting that sulfide nodules and silicate chondrules formed as coexisting melts. This hypothesis is supported by the presence of phosphate inclusions and Cu-rich lamellae in both sulfide nodules and sulfide assemblages within silicate chondrules. Thermodynamic analyses indicate that sulfide melts reached temperatures up to 1138 °C and fS2 of 2 x 10^(-3) atm. These conditions require total pressures on the order of 1 atm, and a dust- or ice-rich environment. Comparison with current models suggest that either the environmental parameters used to model chondrule formation prior to planetesimal formation should be adjusted to meet this pressure constraint, or R chondrite chondrules may have formed through planetesimal bow shocks or impacts. The pre-accretionary environment recorded by unequilibrated R chondrites was therefore highly sulfidizing, and had fO2 higher than solar composition, but lower than the equilibrated R chondrites.Chalcopyrite is rare in meteorites, but forms terrestrially in hydrothermal sulfide deposits. It was previously reported in the R chondrites. I studied thin sections from PRE 95411 (R3 or R4), PCA 91002 (R3.8 to R5), and NWA 7514 (R6) using Cu X-ray maps and EMP chemical analyses of sulfide phases. I found chalcopyrite in all three samples. TEM electron diffraction data from a representative assemblage in PRE 95411 are consistent with this mineral identification. TEM images and X-ray maps reveal the presence of an oxide vein. A cubanite-like phase was identified in PCA 91002. Electron diffraction patterns are consistent with isocubanite. Cu-rich lamellae in the unequilibrated clasts of PRE 95404 are the presumed precursor materials for chalcopyrite and isocubanite. Diffraction patterns from these precursor phases index to bornite. I hypothesize that bornite formed during melt crystallization prior to accretion. Hydrothermal alteration on the parent body by an Fe-rich aqueous phase between 200 and 300°C resulted in the formation of isocubanite and chalcopyrite. In most instances, isocubanite may have transformed to chalcopyrite and pyrrhotite at temperatures below 210°C. This environment was both oxidizing and sulfidizing, suggesting that the R chondrites record an extended history of volatile-rich interaction. These results indicate that hydrothermal alteration of sulfides on the R chondrite parent body was pervasive and occurred even in low petrologic types. This high temperature aqueous activity is distinct from both the low temperature aqueous alteration of the carbonaceous chondrites and the high temperature, anhydrous alteration of the ordinary chondrites.
    • R.A. Windes: pioneer Baptist missionary in Arizona

      Bell, Earl Stanton, 1926- (The University of Arizona., 1966)
    • Rab14: Role in Cell Polarity and Junction Formation

      Sinha, Natasha (The University of Arizona., 2010-08)
      The establishment of polarity in epithelial cells is dependent on the proper distribution of polarity proteins to the apical or basolateral domain. In addition, these cells are dependent on the necessary trafficking of junctional proteins to cells junctions for cell-cell interactions. Rab GTPases are involved in a number of membrane trafficking pathways in the cell. Here we show Rab14's role in regulating the establishment of polarity and junction formation in epithelial cells. Cyst culture was used to show inactive-Rab14 affects single lumen formation and targeting of gp135, an apically targeted protein, thus showing Rab14 may regulate epithelial polarity. In addition, calcium-switch experiments were used to show that not only do cells expressing inactive Rab14 take longer to lose their cell-to-cell contact, but they also regain their contacts more quickly, indicating Rab14 may be playing a role in junction formation. This was further supported by immunostaining experiments examining the distribution of junctional proteins; increased amounts of these proteins at the junction in inactive-Rab14 at the end-point showed that Rab14 may be involved in endocytosis or recycling of junctional components.
    • Rabelais, the man of letters; Rubens, the painter: parallel geniuses of the renaissance

      Kitt, Katherine Florence, 1876-1945 (The University of Arizona., 1927)
    • Rabi formula analogs for double and triple photon absorption process

      Burrows, Michael Daniel (The University of Arizona., 1975)
    • The Rabi­ Yehuda Halevy: The Physical and Conceptual Space of a Sephardic Synagogue in Mexico City

      Widdifield, Stacie G; DiSimone, Cori Beth; Widdifield, Stacie G (The University of Arizona., 2007)
      This thesis analyzes Rabi­ Yehuda Halevy synagogue, which Victor Babani designed and Francisco Canovas built from 1941 to 1942 in the Colonia Roma Sur of Mexico City. I focus on its formal characteristics, as well as its socio-historical context. I examine late-nineteenth century to mid-twentieth century life for Sephardic Jews in Mexico: their cause for immigration, experience in their new homeland, and relations with other Jewish groups and non-Jews in the city. I explore the use of style and iconography in the synagogue in relation to the history and prior employment of these architectural features. Defining "style" in the Rabi­ Yehuda Halevy demands an understanding of the employment of a particular formal language in the design of minority groups' architecture. The process of finding a style to portray national identity in Mexico was parallel to the Mexican Sephardim's use of architecture to articulate their own identity in the city.
    • Race & Class: An Intergenerational Study of Privileged African Americans Educated in Predominantly White and Integrated Suburban Schools

      Griego-Jones, Toni; Davis Welch, JerMara Camille (The University of Arizona., 2015)
      This dissertation sought to better understand the K-12 school experiences of middle and upper income Blacks educated in predominantly White and integrated suburban school systems. Through the narratives of six (6) participants—four females and two males (split evenly between Generations Y and Z)—the study contributes toward knowledge on African American within-group differences and perspectives on K-12 school experiences. The theoretical frames of social location and trust were used to help guide this investigation. Through social location, I sought to understand the interconnectedness of one's race, class, and gender and how these locations impact school experiences. Through the theoretical frame of trust, I sought to understand "overall" participant confidence in the educational processes (academic and social) they underwent. While findings from this dissertation matched some of what is already well-documented on the K-12 school experiences of Black American students in general, by focusing on within-group differences relevant to class and generational grouping, key variances in experiences (not often reported) were revealed. For example, as the study was intergenerational in scope, there was a clear generational divide among study participants in terms of their views relating to how race impacted their K-12 school experiences. Despite the fact that most felt that their schools were not sensitive to their needs as African Americans, race seemed to be less of a concern with Gen Z'ers than with Gen Y'ers. More specifically, while participants from Generation Y were explicit in stating that race had an impact on their school experiences, Generation Z was hesitant to say that race influenced their experiences. Interestingly, as all participants dealt with racial stereotyping, the biggest perpetrators of such stereotypes were peers and not educators. The influence of socioeconomic class on school experiences was also significant as most participants felt that their economic status influenced their cross-cultural interactions. In addition, while the social location of gender was not heavily emphasized in this dissertation, there were variations in perspectives stratified across gender lines. Taken together, a major conclusion was that one's social location (inclusive of generational grouping) cannot be ignored when taking into account the academic experiences of African American students as a whole. Finally, this dissertation highlighted the overall confidence each participant had in the educational process they experienced (academically and socially). Although all encountered some tough circumstances directly related to their social location, everyone felt positive overall about their school experiences—perceiving the academic training they received and inter-ethnic social interactions, as an asset.
    • Race and public policy in Brazil: Immigration, Sao Paulo and the First Republic

      Schwartzman, Kathleen; Penn, David Scott, 1967- (The University of Arizona., 1991)
      This paper investigates the absence of racial public policy in Brazil during the First Republic. Using secondary sources, this paper looks at economic competition and conflict between black and immigrant labor in the state of Sao Paulo and tests the applicability of the split labor market theory of ethnic antagonism--a theory used in explaining the development of ethnic conflict into racial public policy. Such conflict has been a primary factor in the development of racial public policies such as those found in the United States and South Africa. The political organization of black Brazilians and immigrant (primary Italian) groups is also analyzed to discover whether or not these groups would have been capable of translating their economic goals into race-based public policy. The thesis suggests that there was little competition in many areas, and that even where there was little competition, neither group had sufficient political capacity to successfully push for exclusionary public policies based on race.
    • Race and the Matrix Movie Trilogy

      Sanchez, Tani Dianca; Babcock, Barbara A.; Bernardi, Daniel; LeSeur, Geta; Smith, Howard; Smith-Shomade, Beretta; Whaley, Deborah (The University of Arizona., 2006)
      Using a close textual and contextual analysis, I trace themes of gender and race in the Matrix trilogy, arguing for the presence of a parallel, embedded filmic narrative, one that neatly aligns with African-American critical traditions affirming subjugated ideologies, knowledges, communities and forms. Decoding the films through the lenses of race, womanist, film studies and cultural studies theories, I explore this signified, covert storyline through phenotypes, casting choices, plot twists, and extra filmic events. In this dissertation project, I argue that their preponderance, consistency, and coherence are evidence of deliberate commentary. I further claim that that the trilogy can be reasonably understood as a historically motivated critique of Whiteness and White supremacy, offering references to American slavery and ideologies, as well as to cross-racial ideological domination and collective, coalitional and revolutionary change. Since long standing racial and gender understandings (along with their attendant domination and oppression) persist, examining popular films with transformed constructions is useful in supporting frameworks for conceptual change.
    • Race consciousness in American Negro poetry

      Hamilton, Marie Padgett (The University of Arizona., 1926)

      Smith, Mae; WILSON, LLOYD KENTON.; Johnson, Bob; Organist, James (The University of Arizona., 1984)
      This study investigated differences among racial groups and between sex groups on psychometric test performances, demographic data, and vocational potential ratings of an adult rehabilitation client sample. Also, the psychometric and demographic variables were included in discriminant function equations to predict the vocational potential ratings of the white, Hispanic, and black groups and of the total sample. The sample in this study was composed of 99 adult rehabilitation clients who completed comprehensive vocational evaluations between January, 1980, and July, 1983. Each case included complete psychometric and demographic data. Also, a vocational potential rating based on this data, other aptitude and ability testing, work sample performances, behavior observations, and other information obtained by the vocational evaluator was reported for each case. Analysis of variance procedures found no significant differences between the male group and the female group of the total sample on the psychometric and demographic variables, or on the cumulative vocational potential rating. Significant differences were found among the racial groups on mean performance of reading comprehension and arithmetic computation, and on years of education attained. Tukey HSD procedures specified that these differences exist between the white group and the Hispanic group on reading comprehension, between the white group and the black group on arithmetic computation, and between the white and black groups and the hispanic group on years of educaton attained. Also, no significant differences were demonstrated among the racial groups on general mental ability, age, or cumulative vocational potential ratings. Discriminant function analysis procedures applied the psychometric and demographic variables to the prediction of vocational potential ratings of the racial groups and of the total sample. Observation of the resulting prediction equations indicated that some external bias may exist in the use of these equations for predicting vocational potential in white, Hispanic, and black groups. Also, no single predictor variable was the primarily selected variable in all of the discriminant function equations of vocational potential ratings in the total sample. Overall, the predictive power of the discriminant function equations was not sufficient to recommend their use in clinical practice.
    • Race relations in schools: The effects of competition and hierarchy on education, sports participation, and standardized test scores

      Shockey, James S.; Goldsmith, Pat Antonio (The University of Arizona., 1999)
      I investigate the influence of race upon high school student's approaches to education, sports participation, and high school test scores. The theoretical perspective employed suggest that the effect of race upon these items will vary across schools. To explain this school level variation, I employ two theories of race relations: competition theory and the cultural division of labor perspective. Using the National Longitudinal and Educational Study of 1988 (NELS: 88) and multilevel model statistical procedures, support for both theories is found. I conclude that race relations in schools impact student's cultural activities and test scores.
    • Race to the Top-Early Learning Challenge: An Analysis of Impact on IDEIA, Part C Early Intervention Programs

      Umbreit, John; Bohjanen, Sharon Lynn; Bricker, Diane; Antia, Shirin; Levine-Donnerstein, Deborah L.; Umbreit, John (The University of Arizona., 2016)
      Infants and toddlers who live in poverty are more likely to experience developmental delays or disabilities and less likely to access early intervention (EI) services. The federal initiative Race to the Top-Early Learning Challenge (RTT-ELC) was designed to increase access to high quality early learning programs for children at risk for developmental delays due to poverty or disability. Although IDEA, Part C programs were not specifically targeted by this initiative, policies associated with RTT-ELC may have an indirect impact on state EI programs. The purpose of this study was to examine the effects of RTT-ELC on Part C programs by comparing states that received federal grants to states that did not. This study used a social justice framework to identify variables that inform equitable access to high quality Part C programs. Data were extracted from Part C state profiles and compared across states. Awarded states were more likely to increase enrollment of infants and toddlers in Part C Programs and were more likely to use broad eligibility criteria. These findings indicated that although differences were small they could become more pronounced over time. The need for policy change in Part C programs and federal early learning initiatives to directly target infants, toddlers and families in poverty are highlighted through the results of this study.

      BOSWELL, TERRY E.; Fligstein, Neil (The University of Arizona., 1984)
      A theoretical framework is developed for incorporating class conflict dynamics into accumulation theories of labor market segmentation by analyzing the transaction costs of conflict under varying conditions of economic structure and power resources. The theory has the "bottom up" perspective developed in the "new social history." Skill is treated as a status for which workers struggle and internal labor market hierarchies are considered products of the conflicting strategies between capital and labor. Split-labor market theory is also discussed as a method for explaining why workers discriminate. This theory is amended to distinguish between market and class interests of workers, and to take into account the self-perpetuating economic effects of racist discourse. My historical analysis of the metal-mining industry emphasizes the formation of ethnically stratified segments of the labor market in which Chinese and Mexican workers were denied access to the craft-internal labor market for skilled workers. Competition over mining claims under the threat of takeover by mining companies created ethnic antagonism between Chinese and white independent petty-commodity miners. Discrimination by the white independent miners crowded the Chinese into the labor market, which reduced Chinese wages, and induced conflict between white and Chinese wage workers in the company-mines. Ethnic antagonism in combination with intense class struggle produced a segregated labor market between Mexican miners and Anglo supervisors during the initial proletarianization of the mines. Mexican miners were later displaced by Cornish miners who developed a segregated craft-internal labor market. Analysis of the labor process shows that mechanization initially facilitated the struggle by Cornish miners for a skilled status, contrary to homogenization expectations. Mexican miners were relegated to unskilled manual positions.
    • Race, gender, and the labor market: Black and white women's employment

      England, Paula S.; Reid, Lori Lynn (The University of Arizona., 1997)
      Historically, black women's employment levels have exceeded those for white women. However, looking only at young cohorts of women, the employment levels of black and white women were equal by 1969, and by 1991 white women's employment greatly exceeded black women's employment. If this continues to be true for successive new cohorts, it suggests that, overall, white women will soon be working at significantly higher rates than black women for the first time in history. Identifying the determinants of women's employment today becomes an important issue not only for explaining the factors that affect labor market outcomes but also for explaining the prospects for black and white women in the labor market. Utilizing the National Longitudinal Survey of Youth, I use event history methods to analyze the determinants of black and white women's employment in the contemporary U.S., and explain any race gaps in employment that emerge. My findings suggest that a race gap in the hazard of part-time employment exists among women in which the rate of part-time employment is lower for black than white women. This gap is explained by race differences in human capital and past welfare receipt. A race gap in the hazard of full-time employment exists among unmarried women in which the rate of full-time employment is lower for black than white women. This gap is explained by race differences in age, human capital, and past welfare receipt. I find that opportunities and constraints provided by the local economic environment, human capital, family structure, and past welfare receipt are an important influence on black and white women's employment.
    • Race, Nation Building, and the Development of National Identity in Twentieth Century Argentina

      Adams, Alyssa Susan Brideweser (The University of Arizona., 2010-12)
      In my work, I contend that an elite group of intellectuals and officials known as the Generation 1880 led a number of governmental reforms that affected the Argentine self-identity in racialized terms. I argue that Generation 1880 scholars instituted these reforms in order to pursue their own economic interests and maintain social dominance. In the first section of the thesis, I discuss the influences that affected the Generation 1880's construction of their social model. I focus on why Generation 1880 came to define this social model in racialized terms. In the second section of the thesis, I show how social and legal reforms led by Generation 1880 officials enacted the group's racial ideology. Then I examine the way in which these reforms--based upon the elites' racial ideology--effected citizens living in Argentina. Throughout the paper I analyze the way in which Generation 1880's policies affected Argentine self-identity. I maintain that the social pressures exerted by elites, which delineated acceptable from unacceptable social behavior, effected how citizens in Argentina acted. In time, Generation 1880's race-based policies came to define Argentine identity and the traits of the ideal Argentine citizen in racialized terms.
    • Race-crossings at the crossroads of African American travel in the Caribbean

      Kolodny, Annette; Alston, Vermonja Romona (The University of Arizona., 2004)
      Traversing geographical borders frequently allows people the illusion of crossing social, political, and economic boundaries. For African-Americans of the early twentieth century, crossing physical borders offered the promise of freedom from racial segregation and discrimination in all aspects of social, political, and cultural life. Haiti became a site for African-American imaginings of a free and just society beyond the problem of the color line. From the 1920's through the 1980's, African-American travel writing was strategically deployed in efforts to transform a U.S. society characterized by Jim Crow segregation. In the process, Haiti and the rest of the Caribbean were romanticized as spaces of racial equality and political freedom. This project examines the ways in which the Caribbean has been packaged by and for African-Americans, of both U.S. and Caribbean ancestry, as a place to re-engage with romanticized African origins. In the selling of the Caribbean, cultural/heritage tourism, romance/sex tourism and ecotourism all trade on the same metaphors of loss and redemption of the innocence, equality, and purity found in a state of nature. Through analyses of standard commercial tourism advertising alongside of travel writing, I argue that with the growth of the black middle-class in the late 1980's crossings to the Caribbean have become romantic engagements with an idealized pastoral past believed lost in the transition to middle-class prosperity in the United States. African-American travel writers, writing about the Caribbean, tend to create a monolithic community of cultural belonging despite differences of geography and class, and gender hierarchies. Thus, African-American travelers' tales constitute narratives at the crossroads of celebrations of their economic progress in the United States and nostalgia for a racial community believed lost on the road to suburban prosperity. For them, the Caribbean stands in as the geographical metaphor for that idealized lost community.

      Marlatt, Robert B. (Robert Bruce), 1920- (The University of Arizona., 1952)