Volcanogenic copper-zinc sulphide deposits and their geological setting, in the central portion of the murchison greenstone belt, North eastern Transvaal, South Africa

The Murchison greenstone belt is of Archaean age, and occurs within the Kaapvaal Craton of South Africa. The greenstone sequence consists of high-magnesia basalts, overlain by tholeiitic basalts, and, on the northern flank of the Belt, rhyolitic tuffs and lavas form the top of the volcanic pile. All units are overlain by clastic sediments. The entire sequence is intruded by numerous, large, sills of tholeiitic composition; and a large gabbroic complex occupies the base of the rhyolite pile. Collapse and deformation of the sequence produced a tight syncline with a subhorizontal fold axis and vertical axial plane. Low Grade metamorphism accompanied the folding, with temperatures in the range 450-480º and a pressure of about 5.6kbar. Plutons of tonalitic magma were emplaced along the margins of the Belt. Subsequent cooling of these superimposed a thermal metamorphism onto the existing fabric. Massive copper-zinc sulphide deposits were formed immediately following the ryolitic volcanism. Two main, and three minor, deposits were studied in the central part of the Murchison Belt. At the larger deposit, the massive sulphide body is underlain by altered tuff. This alteration comprises an inner core of chlorite with pyrrhotite and chalcopyrite, and an outer, ill-defined sericitic zone containing pyrite and sphalerite. Bulk chemical analyses show an increase in total iron, and decrease in A1(_2)O(_3) and K(_2)O towards the core of the alteration zone. The massive sulphides form a stratiform lens of sphalerite, pyrite, pyrrhotite, and chalcopyrite. Relict, original textures suggest formation as unconsolidated sulphidic sediments on the sea-floor. The lower sulphide horizons were originally rich in chalcopyrite and silica, with only minor sphalerite. As the sulphides accumulated, sphalerite replaced the silica. The upper sulphide horizons show no such replacement, and are generally rich in sphalerite. The other main deposit is similar, but has no underlying alteration zone, A model is presented to account for these, and other, copper-zinc deposits in the Murchison Belt. Following rhyolitic volcanism, sea-water percolated through the underlying rocks, became heated, and set up a system of circulating, hot brines, capable of leaching metals from the rocks. Discharge along pre-existing fractures, precipitated sulphides at the rock/sea-water interface. Initial solutions were hot, with a high Cu/Zn ratio, whilst later, cooler solutions were zinc rich, and deficient in copper

Improving red snapper management and seafood transparency in the Southeastern United States

Robust, accurate data about fish harvest is essential to developing sustainable policies that protect stocks while supporting the fishing and seafood industries. Unfortunately, there are large gaps in knowledge regarding how many fish are caught and what happens to those fish once they reach the dock. My thesis addresses two issues facing the snapper grouper fishery in the Southeastern United States: lack of data in recreational fisheries and the rate of seafood mislabeling. First, I investigated the rate of seafood mislabeling of red snapper using DNA barcoding. I found 72.6% of samples were mislabeled, indicating widespread mislabeling of red snapper on the South Atlantic coast. Second, I surveyed recreational anglers to assess perceptions of electronic reporting and found positive views of using apps and websites to report catch. These results inform fishers, consumers, and managers, and help facilitate the development of sustainable fisheries policies.Master of Scienc

Racial/Ethnic Disparities in Diabetes Care and Outcomes: A Mixed Methods Study

Limited research has examined racial/ethnic differences in diabetes care and outcomes among primary care patients. This study examined racial/ethnic differences in diabetes care and outcomes among an ambulatory patient population and explored patient perceptions of the patient-provider relationship to inform strategies to improve care delivery. Using data from 62,149 adults with diabetes who received care within Atrium Health in 2013, regression models assessed associations between race/ethnicity and the following outcomes: glycated hemoglobin (HbA1c) tests, low density lipoprotein (LDL) and blood pressure (BP) screening, foot and eye exams, and HbA1c, LDL, and BP control. Eleven patients with diabetes and uncontrolled hypertension participated in three focus groups about their perceptions of the patient-provider relationship. Compared to non-Hispanic Whites, non-Hispanic Blacks had 22% to 73% higher odds of receiving screenings (HbA1c, LDL, BP, foot and eye exams;

Queer Gamer Assemblages and the Affective Elements of Digital Games

Centering a discussion of gaming as an embodied experience, this essay explores the affective and embodied relationship between LGBT/queer gamers and video games. Drawing on qualitative interviews with seven queer gamers, I argue in that we should understand gamers as socio-technological assemblages, in order to illustrate how gamer identity, subjectivity, and sociality are enacted through the relationship between the body of a gamer and the game technologies. I further expand upon this by tending to how queer gamers talk about their embodied experiences and affective connections to various games through worlding and storytelling elements. These stories illustrate how games create affective possibilities for connection and belonging for queer gamers. I conclude by arguing that an attention to gaming as an embodied experience expands our conceptualizations of play and helps us understand the worldmaking practices that queer gamers often employ