Now showing items 2006-2025 of 20330


      Bradshaw, John Thomas; Saavedra, S. Scott; Saavedra, S. Scott; Armstrong, Neal R.; Pemberton, Jeanne E.; McGrath, Dominic V.; Zheng, Zhiping; Mendes, Sergio B. (The University of Arizona., 2005)
      A broadband coupling approach applied to a single mode, sol-gel, planar integrated optical waveguide (IOW) was used to create a multichannel attenuated total reflection (ATR) spectrometer. Initial attempts to create an achromatic coupling element for sol-gel waveguides, based upon previous work applied to vacuum deposited glass devices, did not lead to an easily achievable design. Instead a simplified, non-achromatic approach based upon impinging an incident light beam with a large numerical aperture onto an incoupling prism was used. This simplified broadband coupling approach was used to create a sol-gel IOW-ATR spectrometer that transmitted light down to at least 400 nm, and produced a measurable bandwidth of ~ 250 nm; both phenomena are marked improvements upon the capabilities of previously reported devices. An experimental demonstration of this device proved it capable of measuring the visible spectrum of a thin film of horse heart cytochrome c adsorbed to the sol-gel surface at a submonolayer coverage. The broadband spectral capabilities of this sol-gel device were also used to experimentally validate a new method for determining the angular orientation of molecules bound to an arbitrary waveguide surface. In addition to the sol-gel IOW work, the simplified broadband coupling approach was applied to a previously reported multilayered electroactive waveguide device, which was used to collect electrically modulated, broadband spectra for thin films of cytochrome c, as well as a dicarboxyferrocene moiety. Both of these IOW-ATR spectrometers represent improved tools for probing the near-surface chemical environments of molecular assemblies.
    • Broadband Full-Stokes Polarimetry

      Pau, Stanley; Tu, Xingzhou; Chipman, Russell; Liang, Rongguang (The University of Arizona., 2020)
      Broadband full-Stokes polarimetry can capture polarization images over a wide wavelength spectrum, for example visible spectrum (380nm to 740nm), near infrared spectrum (780nm to 2500nm) or both. In this dissertation, we discuss several topics on designing a broadband full-Stokes polarimeter and then demonstrate two polarimeters experimentally. We first study two theoretical problems, the first one is the optimized sensor design for color polarization imaging. This includes three parts, the tiling of N types of optical filters on a 2D rectangular grid that minimizes interpolation error, the choice of color filters and the choice of analyzers, to minimize the influence from noise on color polarization reconstruction. The second problem is how to design achromatic polarization elements. This is the key to enable broadband polarization measurement. We analyze a special case that uses two linear retarders of the same birefringent material and one linear polarizer to achieve an achromatic elliptical polarizer/analyzer. We also address several concerns on choosing the right achromatic analyzer design for polarimeters. Two types of RGB full-Stokes imaging polarimeter are constructed, calibrated and tested. The first one uses a beam splitter and two linear-Stokes cameras to form a division-of-amplitude polarimeter. The second type applies a patterned micro-retarder on a pixelated wire-grid micro-polarizer to form a division-of-focal plane polarimeter. Both can capture the intensity, color and polarization of an optical field in a single shot.
    • Broadband regional waveform modeling to investigate crustal structure and tectonics of the central Andes

      Beck, Susan L.; Swenson, Jennifer Lyn (The University of Arizona., 1999)
      We use broadband regional waveform modeling of earthquakes in the central Andes to determine seismic properties of the Altiplano crust. Properties of the shear-coupled P-wavetrain (SPL ) from intermediate-depth events provide particularly important information about the structure of the crust. We utilize broadband seismic data recorded at the BANJO and SEDA stations, and synthetic seismograms computed with a reflectivity technique to study the sensitivity of SPL to crustal and upper mantle parameters at regional distances. We find that the long-period SPL-wavetrain is most sensitive to crustal and mantle Poisson's ratios, average crustal velocity, and crustal thickness. A comprehensive grid search method developed to investigate these four parameters suggests that although trade-offs exist between model parameters, models of the Altiplano which provide the best fit between the data and synthetic seismograms are characterized by low Poisson's ratios, low average crustal velocity and thick crust. We apply our grid search technique and sensitivity analysis results to model the full waveforms from 6 intermediate-depth and 2 shallow-focus earthquakes recorded at regional distances by BANJO and SEDA stations. Results suggest that the Altiplano crust is much thicker (55-65 km) and slower (5.75-6.25 km/s) than global average values. Low crustal and mantle Poisson's ratios together with the lack of evidence for a high-velocity lower crust suggests a bulk felsic crustal composition, resulting in an overall weak crust. Our results favor a model of crustal thickening involving large-scale tectonic shortening of a predominantly felsic crust. To better understand the mechanics of earthquake rupture along the South American subduction zone, we have analyzed broadband teleseismic P-waves and utilize single- and multi-station inversion techniques to constrain source characteristics for the 12 November 1996 Peru subduction zone earthquake. Aftershock locations, intensity reports, directivity, and spatial locations of seismic moment pulses indicate that the 1996 Peru event ruptured primarily southeast. This earthquake re-ruptured a portion of the 1942 Peru event. We find no indication that the 1996 Peru earthquake ruptured to the northwest, suggesting a sizable gap along the Peru trench corresponding to the position of the northwest flank of the subducting Nazca Ridge.
    • Broadband Seismological Imaging of Flat-Slab Subduction and its Long-Term Impact on Lithospheric Structure and Processes

      Zandt, George; Porter, Ryan Charles; Beck, Susan; Bennett, Rick; Ducea, Mihai; Johnson, Roy (The University of Arizona., 2011)
      In subduction zones, the dip of the downgoing oceanic lithosphere has a profound impact on the nature and extent of deformation as well as the generation of melt. In ~10% of subduction zones, the downgoing slab assumes a low-angle, or horizontal geometry, referred to as flat-slab subduction. The focus of this work is to better understand both the driving forces and impacts of flat-slab subduction on the Earth's lithosphere and asthenosphere. This is accomplished by focusing on three areas impacted by flat-slab subduction. The first area is the Pampean region of central Argentina and Chile, a modern flat-slab subduction zone. In this region, we invert Rayleigh-wave-dispersion data to produce a 3D shear velocity model. The flat slab is visible within the upper mantle as a high-velocity body containing low-velocity pockets that dissipate inboard from the trench. We interpret these velocities in the context of slab hydration and argue that the subducting Nazca plate is initially hydrated at the trench and dewaters as it subducts. The second area is southern California, which was impacted by Laramide flat-slab subduction. In this area, we use receiver functions to locate and parameterize anisotropy within the crust. Results show a persistent NE-SW oriented layer of lower crustal anisotropy. We conclude that this layer consists of schists that were emplaced during Laramide flat-slab subduction and have remained largely intact since. The final component of this work is a study of the Colorado Plateau in which we use ambient-noise tomography and receiver functions to study lithospheric structure. Results show fast crust, a complicated Moho and intact Laramide features throughout the crust beneath the Colorado Plateau while slower crust with a sharp Moho is observed along its margins. Based on these observations, published tomographic data and the volcanic and uplift history of the region, we argue that delamination of the lower crust has occurred beneath the Marysvale volcanic field. This process was driven by the gravitational instability of a dense mafic root that formed during mid-Tertiary magmatism related to the rollback of the Farallon flat slab.
    • Broadband seismology and the detection and verification of underground nuclear explosions

      Wallace, Terry C.; Tinker, Mark Andrew, 1968- (The University of Arizona., 1997)
      On September 24, 1996, President Clinton signed the Comprehensive Test Ban Treaty (CTBT), which bans the testing of all nuclear weapons thereby limiting their future development. Seismology is the primary tool used for the detection and identification of underground explosions and thus, will play a key role in monitoring a CTBT. The detection and identification of low yield explosions requires seismic stations at regional distances (1500 km). However, because the regional wavefield propagates within the extremely heterogeneous crustal waveguide, the seismic waveforms are also very complicated. Therefore, it is necessary to have a solid understanding of how the phases used in regional discriminants develop within different tectonic regimes. Thus, the development of the seismic phases Pn and Lg, which compose the seismic discriminant Pn/Lg, within the western U.S. from the Non-Proliferation Experiment are evaluated. The most fundamental discriminant is event location as 90% of all seismic sources occur too deep within the earth to be unnatural. France resumed its nuclear testing program after a four year moratorium and conducted six tests during a five month period starting in September of 1995. Using teleseismic data, a joint hypocenter determination algorithm was used to determine the hypocenters of these six explosions. One of the most important problems in monitoring a CTBT is the detection and location of small seismic events. Although seismic arrays have become the central tool for event detection, in the context of a global monitoring treaty, there will be some dependence on sparse regional networks of three-component broadband seismic stations to detect low yield explosions. However, the full power of the data has not been utilized, namely using phases other than P and S. Therefore, the information in the surface wavetrain is used to improve the locations of small seismic events recorded on a sparse network in Bolivia. Finally, as a discrimination example in a complex region, P to S ratios are used to determine source parameters of the Mw 8.3 deep Bolivia earthquake.

      Pate, James Jackson (The University of Arizona., 1980)
      Residents of Arizona have looked to post-secondary education as a means of attaining status and security within the community. As a result of this, Arizona's institutions of post-secondary education have grown from a few schools serving a small percentage of the population into three universities and nine community college districts serving (in 1979) approximately 200,000 persons. This study attempts to assist those who will have responsibility for future planning, financing and goverance of Arizona community colleges by addressing two basic questions: (1) How have Arizona's institutions of higher education changed in relation to the changing needs of society? and (2) To what extent and in what ways has the base of higher education been broadened? During the nineteenth century several forces combined to bring about the creation of the two-year college. The public schools grew and prepared a larger segment of the population for higher education. Women and minority groups began seeking higher education. Universities came into existence and emphasized graduate research. Society asked for colleges closer to home so that students could attend while living at home. Two-year colleges began appearing in the latter part of the nineteenth century, and in 1902 the first public two-year college (Joliet) was founded. From its onset, this new institution served the educational needs of the local community. The most frequent reasons for funding two-year colleges during the early period of development were to: (1) keep children close to home; (2) provide a terminal education for those not capable of going on; (3) allow students to complete the first two years of college while living at home; and (4) meet specific local needs. Higher education in Arizona developed along lines similar to the rest of the nation though differences exist. The secularization movement in higher education became strong as the United States matured as a nation and Arizona was affected by the results of that movement. While colonial institutions of higher education were all founded by religious interests, Arizona had but one early institution of higher education founded by a church and it did not offer collegiate work until 1921. Two of the three state universities were founded as two-year normal schools and their students were predominantly females who were preparing for a teaching profession. The University of Arizona was founded as a land grant college to take advantage of federal funds available under the Morrill Act. Until 1920 no other institutions of higher education existed in Arizona. The Phoenix Union High School Board of Education in 1920 began offering evening college classes. That set the stage for establishment of Phoenix College as part of the high school district to provide; (1) two years of collegiate work for students who planned to transfer; (2) vocational training for students who did not plan to transfer? and (3) other subjects as would contribute to the civic and liberal education of those in the community. The period 1920-1960 was one of slow growth for the state's two junior colleges. The three four-year institutions were, however, growing rapidly. By 1958 the college age population in Arizona exceeded 100,000, yet in 1960 less than half that number was enrolled in Arizona institutions of higher education. Since 1960 enrollment in the community colleges of Arizona has grown from 6,396 in 1960 to 106,970 in the spring of 1979. The percentages of women and minorities enrolled show that the community colleges are striving to meet the needs of all segments of the population. The number of students enrolled in the community colleges as of 1979 indicate a promising future for these institutions.

      AL-MASHHDANY, SHOWKET ABDULLAH.; Bartels, Paul G.; Schmutz, Ervin M.; Hull, Herbert M.; Jordan, Gilbert L. (The University of Arizona., 1982)
      Two varieties of sideoats grama (Vaughn and NM-28) were planted in late summer of 1980. The seedlings were treated with a variety of broadleaf weed control treatments at 1-, 3-, 5-leaf, and tillering stages of grass seedling growth to determine the effectiveness of these treatments for controlling weeds and the appropriate stages of grass seedling growth to apply them and consequently on grass establishment, density, forage production and plant height. Four months after seeding, NM-28 stands were more dense, produced more forage and the plants were taller than Vaughn. Treatments of dicamba at 0.28 and 0.56 kg/ha were the most effective herbicidal treatments in controlling weeds and resulted in highest stand densities and yields when applied at the 1- and 3-leaf seedling growth. Both treatments gave over 90% control of weeds at the earlier stages but control decreased at later stages of treatment. Lower control resulted when 2,4-D at 0.56 and 1.12 kg/ha were applied. Even though hand weeding treatment resulted weed-free plots during the first four months of seedling development, it resulted in less stand densities and yields when compared to herbicidal treatments. One year after treatment, Vaughn established into taller stands and produced higher yields than NM-28. Dicamba 0.28 kg/ha and 2,4-D 0.56 kg/ha effectively aided in better stand density and yield. Treatments applied at earlier stages of growth resulted in better establishment of both varieties. Dicamba at 0.28 kg/ha was the most effective herbicidal treatment for both varieties. However, hand weeding evaluated one year after seeding, effectively increased both accessions' yield and was the most effective treatment. Greenhouse and laboratory experiments were conducted to determine the uptake and distribution of ('14)C-2,4-D in both sideoats grama accessions and palmer amaranth seedling plant parts at 1, 4, 8 and 24h after treatment. Over all harvest times, 25.3, 2.8 and 3.1% activity were recovered in Vaughn treated leaf, tillers and crown, respectively. That was compared to 33.9, .68 and 6.8% in the same NM-28 plant parts, respectively. Higher percentages of activity were recovered in palmer amaranth plant parts; 50.5% in treated leaf, 8.5% above treated leaf and 5.4% below.
    • Broken agreement in L2 processing of Spanish

      Montalbetti, Mario; Nicol, Janet; Teller, Matthew Buchanan, 1964- (The University of Arizona., 1998)
      In natural language processing subject-verb agreement sometimes derails yielding ungrammatical sentences such as *The cost of the programs have not yet been estimated. In light of questions concerning the semantic versus syntactic nature of sentence subjects and the interactivity of language processing, researchers have investigated the occurrence and possible causes of erroneous agreement. In complex subject noun phrases such as The cost of the programs, the plurality of the noun in the lower clause has been shown to significantly affect the frequency of subject-verb agreement errors. This effect has been shown in English (Bock and Miller, 1991) and in Italian and Spanish (Vigliocco et al., 1995 and 1996). More importantly, a cross-linguistic difference appears with respect to distributivity, the semantic notion of plurality represented in a singular complex subject noun phrase. The phrase The label on the bottles can have a multiple token interpretation where several instances of the same label are conceptualized. Native (L1) English speakers show no effect for distributivity in light of subject-verb agreement errors, whereas L1 speakers of Italian and Spanish do. The primary question addressed in the current study is the following: Do the subject-verb agreement errors of non-native (L2) speakers of Spanish pattern in the same way as those of L1 speakers of Spanish, particularly with respect to distributivity? The results of the current study indicate that at least some L2 speakers of Spanish are sensitive to the effects of distributivity when processing subject-verb agreement. It is argued that the observed cross-linguistic variation with respect to the effect of distributivity on subject-verb agreement is attributable to differences in processing load resulting from cross-linguistic configurational variation within the subject noun phrase.
    • Bronchodilator effects on mechanisms involved in airway responsiveness

      Witt-Enderby, Paula Ann.; Yamamura, Henry; Bloom, John; French, Edward; Laird, Hugh II (The University of Arizona., 1993)
      The traditional approach to treating asthma includes the use of bronchodilator drugs, in particular β₂-adrenergic agonists and anti-cholinergics. It has been shown clinically that regularly scheduled use of both types of bronchodilators may result in a worsening of asthma. This dissertation evaluates the pulmonary effects of long-term bronchodilator administration in our animal model, the rabbit, at the level of the β-adrenergic receptor (βAR) and muscarinic cholinergic receptor (mAChR) located on airway smooth muscle. A four week infusion of the β₂ agonist bronchodilator, albuterol (6 mg/kg/day), resulted in a desensitization (lower affinity) and down-regulation of the βAR in tracheal smooth muscle (predominantly β₂ βAR subtype), mainstem bronchial smooth muscle (predominantly β₂ PAR subtype), and peripheral lung (predominantly β₁ βAR subtype) with no change in either affinity or βAR number in heart (predominantly β₁ βAR) as determined by radioligand binding analysis using the radioligand dihydroalprenolol ([³H] DHA). However, the βAR were not desensitized functionally in that isoproterenol-induced relaxations were not significantly different from control. In contrast, the functional response of the mAChR was increased significantly as compared to control in that the efficacy of methacholine-induced contractions was increased in mainstem bronchial and similarly in tracheal rings. However, the affinity and density of mAChR were not significantly different from the control values as determined by radioligand binding analysis using the radioligand quinuclidinyl benzilate ([³H] QNB). Chronic anti-cholinergic bronchodilator exposure using atropine (4 mg/kg/day) resulted in an increase in the efficacy of methacholine-induced contractile response of mainstem bronchial and tracheal rings with a concomitant increase in mAChR density in both tissues. Differential regulation of the mAChR may be occurring as demonstrated by experiments which show that chronic atropine exposure increased the M₃ mAChR subtype density to a greater extent than the M₂ mAChR subtype. This suggests that the methacholine-induced hyperresponsiveness seen clinically with chronic anti-cholinergic bronchodilator therapy may be due to an up-regulation of the M₃ mAChR in airway smooth muscle involved in bronchoconstriction.

      Burdorf, Dieter; Kovach, Thomas A.; Telge, Claus; Burdorf, Dieter; Kovach, Thomas A.; Martinson, Steven D.; May, Markus (The University of Arizona., 2015)
      The authors and translators Erich Arendt and Hans Magnus Enzensberger are two key figures in German literature after 1945, known especially for their appropriation of foreign literatures. They both contributed extensively to the reception of Modern Latin American and Spanish Poetry in East and West Germany by translating poets such as Pablo Neruda, César Vallejo and Rafael Alberti. This is the first study to explore the asymmetrically intertwined literary conditions of the two author-translator figures with regard to the ways in which engaging with a foreign text opens up a perspective on the author-translator’s own poetology.

      Qaqish, Samih Shaker, 1950- (The University of Arizona., 1977)

      DUARTE, MIGUEL ANGEL. (The University of Arizona., 1983)
      Dinitro-ortho-cresol (500, 1000, and 2000 ppm) and dormant oil (2.5, 5.0, and 10%) were applied to Thompson Seedless and Perlette grapevines alone and in combination to enhance budbreak and fruitfulness. Applications were made immediately after pruning. Use of these materials during the winter, immediately after pruning, had no effect on either fruitfulness or budbreak in Perlette or Thompson Seedless. Thompson Seedless cuttings collected in August were exposed to six temperatures (7, 13, 18, 24, 29 and 35 C) for five time periods (2, 4, 6, 8 and 12 weeks). After temperature treatment the cuttings were planted in the greenhouse at 24 (+OR-) 1 C. Cuttings exposed to 24, 29 and 35 C broke sooner than those exposed to 7, 13, 18 C at all time periods. The percentage of the bud openings of cuttings at 29 C for a period of 2 and 4 weeks was 95% and 100% respectively. The optimum temperature for budburst was 29 C. Gibberellic acid, Thiourea, dinitro-ortho-sec-butyl-phenol (DINOSEB), potassium nitrate and Endothal were used at two concentrations alone and in combination, to break rest of Thompson Seedless buds. Thiourea at 2% and DINOSEB at 1000 ppm alone were the only treatments which gave a higher percentage of bud opening after 20 forcing days at 25 (+OR-) 1 C temperature. Similar results were obtained from cuttings taken in both winter and summer. Three times after harvest, Perlette and Thompson Seedless were defoliated using the senesce enhancer Endothal. Defoliation times (4, 8, and 12 weeks) after harvest were used. In half of the treatments, regrowth was controlled with Endothal. Gibberellic acid (1000 ppm) Thiourea (2%) and DINOSEB (2000 ppm) were applied at the time of defoliation. The four- and twelve-week defoliation periods with new vine growth controlled for improving budbreak and fruitfulness were best. Growth regulators did not improve the defoliation treatments. The best treatments hastened budbreak by 10 days, more than doubled vine fruitfulness, and increased sugar content in berries resulting in a 10-day earlier harvest than in the control. Results were similar in both Thompson Seedless and Perlette. Thompson Seedless and Cardinal vines grown under Arizona desert conditions were defoliated 4 weeks after harvest with 2000 ppm Endothal. Two weeks later they were pruned and treated with 1000 ppm gibberellic acid, 2% Thiourea, and 1000 ppm DINOSEB. Cardinal and Thompson Seedless vines produced a second commercial crop in December of the same year. Thiourea (2%) and 1000 ppm DINOSEB did not have a significant effect; however, 1000 ppm Gibberellic acid reduced the number of clusters per vine.
    • Buddhism at Crossroads: A Case Study of Six Tibetan Buddhist Monks Navigating the Intersection of Buddhist Theology and Western Science

      Tolbert, Sara; Sonam, Tenzin; Tolbert, Sara; Prather, Edward; Johnson, Bruce; Impey, Chris (The University of Arizona., 2017)
      Recent effort to teach Western science in the Tibetan Buddhist monasteries has drawn interest both within and outside the quarters of these monasteries. This novel and historic move of bringing Western science in a traditional monastic community began around year 2000 at the behest of His Holiness the Dalai Lama, the spiritual head of Tibetan Buddhism. Despite the novelty of this effort, the literature in science education about learners from non-Western communities suggests various "cognitive conflicts" experienced by these non-Western learners due to fundamental difference in the worldview of the two knowledge traditions. Hence, in this research focuses on how six Tibetan Buddhist monks were situating/reconciling the scientific concepts like the theory of evolution into their traditional Buddhist worldview. The monks who participated in this study were engaged in a further study science at a university in the U.S. for two years. Using case study approach, the participants were interviewed individually and in groups over the two-year period. The findings revealed that although the monks scored highly on their acceptance of evolution on the Measurement of Acceptance of Theory of Evolution (MATE) survey, however in the follow-up individual and focus group interviews, certain conflicts as well as agreement between the theory of evolution and their Buddhist beliefs were revealed. The monks experienced conflicts over concepts within evolution such as common ancestry, human evolution, and origin of life, and in reconciling the Buddhist and scientific notion of life. The conflicts were analyzed using the theory of collateral learning and was found that the monks engaged in different kinds of collateral learning, which is the degree of interaction and resolution of conflicting schemas. The different collateral learning of the monks was correlated to the concepts within evolution and has no correlation to the monks’ years in secular school, science learning or their proficiency of English language. This study has indicted that the Tibetan Buddhist monks also experience certain cognitive conflict when situating Western scientific concepts into their Buddhist worldview as suggested by research of science learners from other non-Western societies. By explicating how the monks make sense of scientific theories like the theory of evolution as an exemplar, I hope to inform the current effort to establish science education in the monastery to develop curricula that would result in meaningful science teaching and learning, and also sensitive to needs and the cultural survival of the monastics.

      Hosley, Richard; Clark, James D. (The University of Arizona., 1967)
    • Building "Consciousness and Legacies": Integrating Community, Critical, and Classical Knowledge Bases in a Precalculus Class

      Turner, Erin E.; Gutiérrez, Rodrigo Jorge; Turner, Erin E.; Wood, Marcy; Civil, Marta; Gutstein, Eric (The University of Arizona., 2013)
      Grounded in Freire's (1970) notion that the purpose of education in an unjust society is to bring about equality and justice, Critical Mathematics (CM) scholars consider mathematics to be a tool to understand, critique, and change the world by deconstructing power structures that marginalize certain groups. In particular, Gutstein's (2006) framework for integrating students' Community, Critical, and Classical mathematics knowledge bases (3 Cs) advocates for mathematics instruction that incorporates students' informal and everyday experiences. This involves investigations into social phenomena that draw on students' perspectives and experiences to inform critical analysis, while developing mathematical power. This dissertation presents the findings from a critical ethnographic study of a veteran teacher of color's approach to integrating the 3 Cs in his Precalculus class. In addition to discussing the creation and implementation of CM activities, this study examined the perspectives and participation of students of color during these curricular units. Data from 12 students of color, including interviews, focus groups, classroom observations, and student work, were collected over the course of a school year. Detailed descriptions are presented of three CM activities (i.e., Local Poverty Unit, AIDS Lab, Gini Coefficient Unit).Analysis of student participation found that students engaged most fully when units integrated transparent mathematical concepts into non-traditional social investigations. CM activities that lacked mathematical activity and/or reproduced traditional instructional norms resulted in high levels of open and passive resistance. Analysis of student perspectives found that repeated opportunities to integrate the 3 Cs promoted shifts in students' orientation toward mathematics. Some students came to see new ways of learning and using mathematics that included various means of participation and connections to one's personal life. In the end, students recognized that mathematics could be relevant and powerful for making sense of the world (reading the world), and acknowledged its potential for bringing about change (writing the world). Findings point to the essential role personalization plays in helping students develop a sense of social agency. That is, by prioritizing Community knowledge and inviting students to incorporate personal and family stories, teachers promote students' integration of their personal perspectives and experiences into their critical analyses.
    • Building a Red Sequence in Cosmological Hydrodynamic Simulations

      Dave, Romeel; Gabor, Jared; Impey, Chris; Narayanan, Desika; Thompson, Rodger; Zabludoff, Ann; Dave, Romeel (The University of Arizona., 2011)
      Despite years of study, the origins of red galaxies are not fully understood in a cosmological context. We develop new models for quenching star-formation and producing red galaxies in cosmological hydrodynamic simulations. We start with phenomenological models applied in post-processing to previously-run simulations. We focus separately on mergers and hot haloes – akin to “quasar mode” and “radio mode” feedback – as the drivers shutting down star-formation. With appropriate parameter choices, each model can produce a reasonably good match observed color-magnitude diagrams and red galaxy luminosity functions at redshift zero. We uncover some difficulties with these models in general, including red galaxy stellar populations that appear too blue by 0.1 magnitudes in g − r due to a metallicity deficit. Building on the post-processing models, we develop quenching models for simulations that run on-the-fly. Again, we test merger quenching and hot halo quenching separately. We model merger feedback as > 1000 km s⁻¹ winds motivated by observations of post-starburst galaxies, and wemodel hot halo feedback by continuously adding thermal energy to circum-galactic gas in haloes dominated by gas above 250, 000 K. Merger quenching temporarily shuts down starformation, butmerger-remnant galaxies typically resume star-formation with 1− 2 Gyrs thanks to accretion of newfuel fromthe IGM.Hot halo quenching successfully produces a realistic red sequence, providing a good match to the observed red galaxy luminosity function. Despite some minor difficulties with hot halo quenching, we examine its effects in more detail. Specifically, we study the evolution of the simulated red sequence over time. We find that galaxies with stellar mass ∼ 10¹¹M⊙ are the first to populate the red sequence at z ≳ 2, with significantly fewer red galaxies around 10¹⁰M⊙ until z ≈ 0. We show that massive galaxies grow substantially after moving onto the red sequence, primarily through minor mergers. We also examine the relationship between quenching and environment.
    • Building a Society of Equals - Relational Egalitarianism on Democracy, Relationships, and Competition

      Christiano, Thomas; Chow, Joel K. Q.; Schmidtz, David; Wall, Steven; McKenna, Michael (The University of Arizona., 2021)
      What is equality? Why do we value it? And what does an equal society look like? For relational egalitarians, equality is about individuals relate to one another: equality requires that individuals regard and treat each other as equals. Different relational egalitarians have fleshed out this idea of relational equality in different ways. This dissertation comprises four papers where I explore and examine different interpretations of relational egalitarianism and their application to three areas in political philosophy: i) the justification of democracy; ii) the ideal of equality in personal relationships; and iii) competitive institutions. For the first topic about the justification of democracy, I understand relational egalitarian accounts of democracy as defending two main claims. The first is a claim about democracy’s value: that democracy is not only instrumentally but intrinsically valuable. The second is a claim that democracy is justified because it is the embodiment of a relational egalitarian value of equal power. In the first chapter of this dissertation, “On Democracy and Intrinsic Value”, I argue that relational egalitarian attempts to defend the Intrinsic Value Thesis are unsuccessful. In general, I argue that relational egalitarians fail to provide a clear link between the purported value of egalitarian relationships and democratic procedures. I tentatively conclude therefore, that attempts to refute instrumental accounts of democracy via relational egalitarianism fail. In place of these accounts, I provide an alternative—I argue that a view which takes deliberation at the heart of democracy can better explain why democracy has intrinsic value. The second chapter “On Political Instrumentalism and the Justification of Democracy”, considers another possible interpretation of instrumentalism by Daniel Viehoff. Viehoff argues that political instrumentalism’s core concern is not with the kind of values that justify power relations, but that considerations of respect for individual agency impose limits on the kinds of goods that can justify power relations. I argue that while Viehoff’s version of instrumentalism overcomes certain longstanding criticisms of instrumentalism, it faces two problems. Chapter 3, “Respect and Equality”, turns to the second related topic—the question of why equality matters in personal relationships. On an influential strand of relational egalitarianism, we can explain why political equality matters by an appeal to egalitarian personal relationships such as friendships or marriages. On these views, equal power is a constitutive component of showing equal concern for one another. Call this the Argument from Equal Concern. I argue that while the Argument from Equal Concern seems plausible and attractive, it ultimately fails. In place of Viehoff’s account, I suggest an alternative—the Respect Model. Put briefly, the Respect Model holds that an equal distribution of power is necessary to maintain and sustain an egalitarian relationship over time by showing respect for each party’s interest and ability to shape the relationship in accordance with their own preferences, desires, and values. Finally, the fourth chapter turns to the issue of competitive institutions and their moral status in a liberal society. According to Waheed Hussain, competitive institutions pose a moral problem when they erode the relational ideal necessary for upholding political society by creating reasons for estrangement with respect to certain important goods, specifically Rawlsian Primary Goods. However, Hussain does not believe that all competition should be ruled out. Rather, we should seek to moderate the stakes of competition. Call this the Competition Proviso. Crucially, Hussain holds that his Estrangement Account only focuses on how the relational ideal of community must shape our basic institutions and does not make the further claim that the ideals for these background institutions should shape our choices within them. Call this the Strict Institutional Interpretation. In this chapter, I argue that while Hussain’s insights about the importance of community are powerful, the Estrangement Account cannot satisfy both the Competition Proviso and the Strict Institutional Interpretation. I argue that insofar as social norms link certain material goods to associational goods such as friendship or marriage, it seems inevitable that these social norms would create reasons for estrangement with respect to PSGs. If that is the case, then the Estrangement Account fails to satisfy the Competition Proviso. I then argue that to escape this problem, Hussain should abandon the Strict Institutional Interpretation. However, it seems that this might leave us in an impasse—it seems that we cannot hold onto the other liberal value of liberty while abandoning the Strict Institutional Interpretation. In the second half of the chapter, building upon Hussain’s insights about the significance of solidarity, I suggest an alternative account that can break this impasse—a relational egalitarian account. I argue that this account has important implications for our ordinary understanding of political morality and individual obligations with regards to our voluntary choices regarding the associational goods.
    • “Building A Wall of Resistance:” Collective Action and Rationality in the Anti-Terror Age

      Earl, Jennifer; Reynolds-Stenson, Heidi; Stryker, Robin; Zavisca, Jane (The University of Arizona., 2018)
      When people come together in protest, and especially when this protest threatens public order or the status quo, states often attempt to deter and suppress protest and restore order. A perennial question among social movement scholars is whether such repression is effective at chilling protest or instead backfires, spurring greater mobilization. Empirical studies attempting to adjudicate between these two possibilities have failed to create consensus, finding a wide array of empirical consequences for repression. I propose a new way of understanding the effects of repression that draws on and synthesizes insights from both rational choice and cultural traditions in social movement theory. I develop this explanation through analysis of in-depth interviews and observations with activists in Arizona who have experienced state repression, as well as qualitative content analysis of activist literature. These data demonstrate that how individual activists perceive and respond to state repression has little to do with the type or severity of repression they experience. Rather, protest groups fundamentally shape how individuals experience and consider the risks and rewards of participation in collective action, including those related to repression and, as a result, individuals react very differently to objectively similar experiences of repression. Specifically, I document three ways in which group practices and meanings alter how individuals think about and act in response to state repression. First, groups shape how individuals understand and experience the repressive situations they face by working to prevent and prepare for repression and by supporting those individuals who bear the brunt of these costs. Second, groups shape individuals’ orientations to repression by re-defining the goals of protest, effectively shifting repression from a cost to a sign of the importance of their actions and refocusing activists on the importance of protest as an activity, even if larger goals are hard to achieve. Finally, groups shape individuals’ dispositions by cultivating salient activist identities that render decisions to participate moot and make participation and repression taken for granted parts of an activist identity. My data show that all three processes help explain why some persist, while others disengage, following experiences of state repression and furthermore make clear that one can only understand these dynamics by bringing rational choice and cultural explanations together. More broadly, while research on social movements since the 1970s has largely been divided between studies built on rati
    • Building Alliances: A Partnership between a Middle School Mathematics Teacher and a University Researcher

      Wiles, Peter; Fernandes, Anthony; Wiles, Peter; Civil, Marta; McGraw, Rebecca; Doyle, Walter; Arenas, Alberto (The University of Arizona., 2007)
      This case study examined the evolution of a partnership between a middle school mathematics teacher and a university researcher around discussions on the content and teaching of mathematics. In particular, the study sought to examine the evolution of the partnership, the constraints present for the teacher and researcher, the impact of the partnership on the mathematical and pedagogical issues that arose in planning, teaching, and assessment, and the impact on the tasks that the teacher chose and implemented in the classroom. Drawing from the literature on collaborations and the emergent perspective, the evolution of the partnership occurred through three stages, determined by the content-teaching tensions. The first stage focused on the mathematics content, with the agenda being set and run by the researcher. The second stage gave rise to the content-teaching tensions as the teacher shifted the discussions from content to a focus on lesson planning and teaching. Tensions were resolved in the third stage with the teacher taking a proactive role in the discussions of lesson design and teaching. The mathematical issues in planning and teaching reflected the shift in the partnership where in the beginning the discussions focused on the mathematical content, later discussions centered on a combination of content, pedagogy, and student thinking. The assessment discussions addressed differences between the language of the curriculum and the district and state tests.The shift in the partnership can be attributed to the teacher's choice of high level mathematics tasks, the subsequent adoption of a conceptually based mathematics curriculum and the effective management of the dialectic tensions by both partners. This study illustrated that generating perturbations and effective management of dialectical tensions has the potential for a fruitful collaboration between teachers and researchers.

      Soto Santibanez, Miguel Angel; Cellier, Francois E.; Hariri, Salim; Zeigler, Bernard P. (The University of Arizona., 2010)
      About 400 million years ago sharks developed a separate co-processor in their brains that not only made them faster but also more precisely coordinated. This co-processor, which is nowadays called cerebellum, allowed sharks to outperform their peers and survive as one of the fittest. For the last 40 years or so, researchers have been attempting to provide robots and other machines with this type of capability. This thesis discusses currently used methods to create artificial cerebellums and points out two main shortcomings: 1) framework usability issues and 2) building blocks incompatibility issues. This research argues that the framework usability issues hinder the production of good quality artificial cerebellums for a large number of applications. Furthermore, this study argues that the building blocks incompatibility issues make artificial cerebellums less efficient that they could be, given our current technology. To tackle the framework usability issues, this thesis research proposes the use of a new framework, which formalizes the task of creating artificial cerebellums and offers a list of simple steps to accomplish this task. Furthermore, to tackle the building blocks incompatibility issues, this research proposes thinking of artificial cerebellums as a set of cooperating q-learning agents, which utilize a new technique called Moving Prototypes to make better use of the available memory and computational resources. Furthermore, this work describes a set of general guidelines that can be applied to accelerate the training of this type of system. Simulation is used to show examples of the performance improvements resulting from the use of these guidelines. To illustrate the theory developed in this dissertation, this paper implements a cerebellum for a real life application, namely, a cerebellum capable of controlling a type of mining equipment called front-end loader. Finally, this thesis proposes the creation of a development tool based on this formalization. This research argues that such a development tool would allow engineers, scientists and technicians to quickly build customized cerebellums for a wide range of applications without the need of becoming experts on the area of Artificial Intelligence, Neuroscience or Machine Learning.