Now showing items 37330-37349 of 39116

    • U-Pb and Hf Isotopic Analysis of Detrital Zircons from Paleozoic and Cretaceous Strata of Southern Vancouver Island, British Columbia

      Gehrels, George E.; Alberts, Daniel G.; Kapp, Paul; Nelson, JoAnne (The University of Arizona., 2019)
      Wrangellia, an exotic arc terrane to North America, is interpreted to have been constructed near the margin of the Paleo-Arctic and Paleo-Pacific during middle-late Paleozoic time, before finally accreting to the western margin of North America during Late Jurassic to Early Cretaceous time. Utilizing the detrital zircon record of Paleozoic sedimentary rocks and Cretaceous basin fill we can provide further insight into the magmatic and depositional evolution of southern Wrangellia. 1422 U-Pb LA-ICPMS analyses from five samples of the Fourth Lake Formation in the Carboniferous Buttle Lake Group were performed. 1055 U-Pb LA-ICPMS analyses from four samples of the Comox formation within the Cretaceous Nanaimo Group were acquired in order to provide a broader sampling of the Lower Mesozoic-Paleozoic rocks of Vancouver Island. U-Pb analyses within the Fourth Lake Formation reveal prominent Carboniferous age peaks (344, 339, 336, 331, and 317 Ma), with minor pre-400 Ma grains from adjacent terranes of Paleo-Arctic origin. Paleozoic detrital zircons exhibit juvenile, with ƐHf(t) values between +15 and +5. U-Pb analyses of Nanaimo Group sedimentary rocks reveal dominant peak ages at 341, 195, 167, and 86 Ma. All major populations yield juvenile epsilon ƐHf(t) values in the range of +15 to +6. The detrital zircon U-Pb geochronologic and Hf isotope data in this study suggest that sediment from the Fourth Lake Formation was derived mainly from bimodal magmatism within the Paleozoic southern Wrangellia arc system as well as minor contributions of recycled detritus from the adjacent Alexander Terrane. Hf isotope data from the Comox Formation indicate that Triassic and Jurassic igneous rocks of the Bonanza Arc, and Late Jurassic-Early Cretaceous sources from the central Coast Mountains Batholith (CMB), are highly juvenile. This new geochronologic and geochemical data set contributes to a new tectonic model for the Paleozoic Southern Wrangellia Arc system from Late Devonian to Early Permian time and reveals, during Cretaceous time, very locally derived detritus was deposited in sedimentary basins along the inboard margin of Wrangellia.
    • U-Pb Geochronology Of Igneous Rocks In Southeastern Arizona To Constrain A Minimum Age Of Deposition For The Fort Crittenden Formation With Implications For Laramide Tectonics

      Carrapa, Barbara; Smith, Joshua Martin (The University of Arizona., 2019)
      The Fort Crittenden Formation comprises a ~2.5 km thick sequence of fluvial-alluvial upper-Cretaceous sedimentary units of interest due to rich fossil record, and implications for Laramide tectonics in southeastern Arizona. Dating of the Fort Crittenden Formation is important for understanding geological evolution of Arizona and western North America. Previous studies (Dickinson and Hayes, 1986) provided an age of ca. 75 Ma based on K-Ar geochronology for the age of deposition for the Fort Crittenden Formation. The Salero Formation, which is stratigraphically on top of the Fort Crittenden Formation was dated to ca. 74 Ma (Inman, 1982) using K-Ar geochronology. Based on paleontological content, the Fort Crittenden Formation has been interpreted to be Campanian-Maastrichtian in age (84-67 Ma). This research aims at more precisely constraining the depositional age of this formation using zircon Uranium-Lead geochronology (LA-ICPMS) from four samples (Figure 1): a hypabyssal intrusion within the Fort Crittenden Formation, an andesite unit of the Salero Formation overlying the Fort Crittenden Formation near Mount Fagan, a dacite unit of the Salero Formation above the andesite unit, and a rhyolite unit of the Salero Formation. New zircon U-Pb data ages from the intrusion (75.8 Ma), dacite (75.4 Ma), and rhyolite (73.4 Ma) reveal an abundance of late-Cretaceous ages for these samples whereas U-Pb ages of the andesite sample reveal no late-Cretaceous ages. Our results indicate the top of the Fort Crittenden Formation is 75 Ma (older than Maastrichtian), and the base is older than 75 Ma. This has implications for the timing and mechanism of Laramide tectonics and magmatism in southeastern Arizona. Deposition of the upper Fort Crittenden Formation marks changes in volcanism from andesitic-dacitic (75.4 Ma) to rhyolitic (73.4 Ma) over 2 million years, which may reflect changes in subduction dynamics.
    • U-Th-Pb LA-ICP-MS Detrital Zircon Analysis of the Triassic Chinle and Moenkopi Formations and Permian Coconino Sandstone of Chinde Point, Petrified Forest National Park, Arizona

      Gehrels, George E.; Giesler, Dominique; Carrapa, Barbara; Reiners, Peter W. (The University of Arizona., 2019)
      The Petrified Forest National Park (PEFO) of Arizona preserves outstanding exposures of the Triassic Chinle and Moenkopi Formations that are underlain by upper Paleozoic strata of the Coconino Sandstone. In 2013, drill core was collected from these strata in an effort to establish links with the astrochronological time scale developed in the Newark basin. Other workers involved in this project are using this core to refine and improve an absolute time scale employing Milankovitch cycles. To improve constraints on provenance and depositional ages of the Coconino, Moenkopi, and Chinle formations, we acquired 7,511 individual U-Pb detrital zircon dates from 29 samples from the core. Comparison of U-Pb ages with ages of rocks in various potential source terranes suggests that our samples were shed from rocks of the Archean (2.7-2.5 Ga) Wyoming Province and Paleoproterozoic terranes (2.1-2.0 Ga) of the Canadian Shield, the Yavapai and Mazatzal Provinces (1.8-1.6 Ga), Ancestral Rocky Mountains (1.8-1.4 Ga), midcontinent basement and overlying platformal strata (1.5-1.3 Ga), Grenvillian orogen (1.3-0.95 Ga), Yucatán-Campeche block (720-420 Ma) and Amarillo-Wichita uplift (600-500 Ma), Appalachian orogen (450-350 Ma), eastern Mexico magmatic arc (310-232 Ma), and Triassic magmatic arc of western North America (230-210 Ma). The youngest peak age of the Permian Coconino sandstone is 260 Ma, whereas the youngest peak age for the Early-Middle Triassic Moenkopi Formation is 250 Ma. All samples from the Late Triassic Chinle Formation have youngest peak ages from 224-214 Ma. These maximum depositional ages compare well with CA-TIMS and ID-TIMS dates from strata of the Moenkopi and Chinle Formations, as well as the Adamanian-Revueltian land vertebrate faunachron (LVF) from Lucas (1998) and Parker and Martz (2011). U-Pb detrital zircon ages document a depositional hiatus/erosional period of ~250-225 Ma between the Moenkopi and Chinle Formations.

      Pietz, David; Maes, Christine Marie (The University of Arizona., 2018)
    • The U.S. foreign policy in the Persian Gulf, 1968-1988: From regional surrogate to direct military involvement.

      Bahramzadeh, Mohammad Ali.; Whiting, Allen S.; Wahlke, John C.; Muller, Edward N. (The University of Arizona., 1993)
      This study examines the U.S. foreign policy toward the Persian Gulf from 1968 to 1988 with an attempt to explain why and how particular U.S. foreign policy decisions were made. It further attempts to determine whether each president, within this time frame, pursued a different foreign policy toward the region. The indicators used to longitudinally measure foreign policy change were trade, both imports and exports between the U.S. and the Persian Gulf countries, bilateral treaties between them, and U.S. military sales to them. By examining the effect of presidential succession on selected patterns of American foreign policy behavior toward the area it is apparent that the pattern of interaction exhibits a clear continuity and in fact different administrations have not drastically altered the fundamental thrust of U.S. foreign policy. Furthermore, from a broad historical perspective, this study challenges the conventional notion that U.S. foreign policy has been "short-sighted" and often erratic. By examining two case studies, namely the Iran-Iraq war and U.S. decision to reflag Kuwaiti oil tankers, one can readily see that U.S. foreign policy is far from being reactive in its approach. In general, the evident suggests that the U.S. foreign policy in the Persian Gulf, in a broad conceptual framework, can be explained as a part of the rational decision making process where the U.S. foreign policy makers select the alternatives best suited to maximize the strategic goals and objectives.
    • U.S. smelter acid sales and revenues: The implications of adopting European acid trade and marketing practices

      Rieber, Michael; Virdis, Maria Rosa, 1953- (The University of Arizona., 1989)
      Sulphuric acid obtained as a byproduct of non-ferrous metal ore smelting is often the mandatory result of stringent environmental policies adopted in the industrialized countries to limit sulphur dioxide emissions. For the primary copper industry in the southwestern U.S., improvement of sulphuric acid marketing and distribution economies is a critical factor. In this thesis, through a comparison of the European and U.S. sulphuric acid market structure and organization, both the opportunity and the implications of adopting European acid marketing practices are discussed. A more centralized system of acid distribution, as in the European model, if applied to the U.S. smelter acid market, proves to be potentially beneficial for net revenue enhancement. A rationalization of the logistic aspects could substantially reduce acid transportation costs, allow repayment of at least average variable costs of production and improve southwestern smelter acid competitiveness in the domestic markets.
    • UA Design Build Fly: Senior Design Project

      Conatser, Stephen Glenn; Douglas, Amy; Roberts, David; Tingstad, Kelly; Troyer, Jason (The University of Arizona., 2012-05)
    • UA Pay to Play The Evolving NCAA Landscape: University of Arizona

      Sharkey, Nancy; Mohler, Megan Ashley (The University of Arizona., 2015)
      The NCAA is currently involved in at least three separate lawsuits that threaten imminent change to the current model of intercollegiate athletics. Although these suits could change the sports landscape, they are ultimately trying to give student-athletes more rights as individuals and determine if they should be compensated in addition to athletic scholarships. There is much ongoing debate over whether these possible changes will benefit the athletes or hinder them. This thesis explores the viewpoints of these current issues from three types of authorities: university athletic administrators, NCAA representatives, and athletes of past and present. Each section contains the pertinent interviews with each authority for the purpose of unique insight on how the lawsuits will affect policies, Title IX, economics, and student-athletes.

      Parker, Sheila; UGBOR, OBUMNEKE JESSICA (The University of Arizona., 2016)
      Sexually Transmitted Infections (STIs) are commonly transmitted among college students through risky sexual behavior. Data shows that sexual health behavior habits differ between female identified college students and male identified college students. Results from the University of Arizona Campus Health 2015 Health and Wellness Survey indicate that undergraduate males are less likely than their female counterparts to seek testing for STIs. UA Project Get Tested is a program that aims to address this disparity. A survey was conducted to assess what knowledge UA undergraduate males have about STIs and their perceptions regarding susceptibility towards contracting them. The survey results were consistent with the 2015 Health and Wellness results, showing that 30% of the respondents have not been tested for an STI within the last six months. Using this information, the program plan for UA Project Get Tested was created, containing the goals, objectives, and intended outcomes once implemented and evaluated. Upon successful completion of UA Project Get Tested, STI testing among UA undergraduate males will increase, as well as their knowledge about what makes them susceptible to contracting STIs.
    • UA Wear and Share: A Campus Wide Clothing Swap A Case Study on how to Engage Students in Sharing their Unused Clothing

      Iuliano, Joseph E.; Zermeno, Zola (The University of Arizona., 2016)
      The way in which clothing, the second largest consumer sector, is produced and consumed poses a variety of environmental threats. A huge driver of unsustainable clothing production is the fast fashion industry where clothing styles are produced, consumed and disposed of at alarmingly quick rates. This type of clothing production is supported by societies need for new and trendy clothing. A demographic affected by this false need of new clothing are college aged students, thus college campuses and universities make have huge potential to be a part of a solution. In recent years the sharing economy has become a popular form of trade. Large-­‐scale campus clothing swaps may be a method through which the environmental footprint of students’ livelihoods can be reduced.
    • UA Wear and Share: A Case Study on how to Engage Students in Sharing their Unused Clothing

      Zermeno, Zola; College of Architecture, Planning and Landscape Architecture; Helm, Sabrina PhD; Blowers, Paul PhD; Iuliano, Joey (The University of Arizona., 2016-05-04)
      The way in which clothing, the second largest consumer sector, is produced and consumed poses a variety of environmental threats. A huge driver of unsustainable clothing production is the fast fashion industry where clothing styles are produced, consumed and disposed of at alarmingly quick rates. This type of clothing production is supported by societies need for new and trendy clothing. A demographic affected by this false need of new clothing are college aged students, thus college campuses and universities make have huge potential to be a part of a solution. In recent years the sharing economy has become a popular form of trade. Large-scale campus clothing swaps may be a method through which the environmental footprint of students’ livelihoods can be reduced.
    • UA62784; a Putative Inhibitor of CENP-E Kinesin-like Protein and its Effects on Human Pancreatic Cancer Cells

      Dorr, Robert T.; Henderson, Meredith C.; Dorr, Robert T.; Bowden, G. Timothy; Gerner, Eugene W.; Cress, Anne E.; Martinez, Jesse D. (The University of Arizona., 2008)
      UA62784 is a novel fluorenone identified in a biologic screen of compounds that are selectively cytotoxic in DPC4 (deleted in pancreatic cancer)-deleted pancreatic cancer cells. We sought to determine the mechanism of action of UA62784, and discovered it to be a potent mitotic inhibitor. UA62784 affects the ATPase activity of the mitotic kinesin centromere protein E (CENP-E), but does not affect other known mitotic kinesins. This inhibition of ATPase activity is not caused by an inhibition of microtubule binding nor is it caused by a failure of the kinesin to translocate to the nucleus during mitosis. Despite the anti-cancer properties of this drug, UA62784 is relatively insoluble and is not suitable as a lead compound for further development.Once we determined the mechanism of action of UA62784, we sought to determine if analogs would demonstrate the same potent mitotic inhibition while also offering properties such as increased solubility. A small library of chemical analogs was generated wherein each compound was a slight variation of UA62784 (termed the DPC series). Several potential leads were identified which exhibited increased solubility and/or increased cytotoxic activity. When tested for CENP-E ATPase inhibition, some compounds were noted to inhibit other kinesins as well. We therefore created a screen where each of the DPC compounds was tested for activity in Eg5, CENP-E, MKLP-1, MCAK, and KIF3C kinesins. Within these data, there is a correlation between cellular IC50 and kinesin ATPase inhibition for CENP-E and MKLP-1. A few compounds emerged from these studies, including DPC046, which has a low cellular IC50 and inhibits all five kinesins to some degree. DPC046 was used in a mouse xenograft study to determine in vivo efficacy, but no significant tumor shrinkage was seen, likely due to solubility limitations affecting the amount of bioavailable compound.From these studies we conclude that the cytotoxic effects seen in UA62784 and its analogs are due, at least in part, to their inhibition of kinesin proteins. We demonstrate that compounds that inhibit CENP-E and other kinesin proteins hold promise in cytotoxically targeting pancreatic cancer cells. Further development is needed to optimize DPC046 compound solubility in order to increase in vivo efficacy.

      Kroeger, Sue; Emmert, Clare Ann (The University of Arizona., 2018)
      As the student population on University campuses continues to diversify, there is an increasing need for course curriculum that models the core values of access, equity, and inclusion. Universal Design for Learning, a theoretical framework that expects diversity, can be used in the design and implementation of course curriculum that facilitates effective learning for all students. Using the UDL Guidelines Checklist, two courses in the department of Family Studies and Human Development were evaluated for their alignment with UDL principles. Results indicate that UDL alignment is poor across both course curriculums, emphasizing the need for further research that explores the barriers to UDL implementation. Introduction For many, the experience of going to college is invaluable, as it brings both exciting and challenging opportunities to learn. While universities enroll individuals from vastly different backgrounds, including some who have already held a career and others who have yet to decide which major fits their interests, there is one theme that unites the student body: the years spent on a college campus can be transformative. As individuals take classes, live on their own, and make more choices independently, they develop lifelong friendships, greater responsibility, and a career interest. Undeniably, the university experience serves as a conduit for personal growth for many who participate. For people with intellectual disabilities, this life-changing experience is not typically accessible. Universal Design for Learning (UDL) is an evidence-based theoretical framework that targets this gap, as it aims to create course curricula that are accessible to not only students with diverse learning needs, but to all learners. This project serves as a starting point for evaluation of UDL implementation on the University of Arizona campus by assessing two Family Studies and Human Development (FSHD) course curricula.
    • Ugly Duckling Hans Christian Anderson Memorial Library

      Harrison, Ashley Nicole (The University of Arizona., 2009-05)
    • Ukranian-Russian Relations as a Reflection of Political Leadership

      Francis, Ashley Christine (The University of Arizona., 2011-05)
    • uLocal Benchmark Evaluation

      Brewer, Chris L; Sexton, Nick; Mintzis, Julian; Bansal, Abhay (The University of Arizona., 2009-05)
    • Ultimate flexural strength of flat slabs: with particular attention to membrane action

      Sakolosky, John Joseph, 1941- (The University of Arizona., 1966)
    • Ultimate performance limitations of phase-locked loops

      Paul, William Vincent, 1928- (The University of Arizona., 1961)