Conviviality in Bellville: an ethnography of space, place, mobility and being

This study provides insight into the experiences of mobility and migration in contemporary South Africa, contributing to a field of literature about multiculturalism and urban public space in globalizing cities. It is a study of how the mystique of conviviality configures amongst a diverse migrant and mobile population that frequents Bellville's central business district surrounding the train station - an area located approximately 25 kilometres from Cape Town, and a prominent destination for informal trading, shop keeping, and other ad hoc livelihoods. Understanding the emergence of conviviality and the forms it takes in this particular locality lies at the heart of this thesis. I argue that conviviality emerges out of shared understandings of Bellville as a zone of mobility, of safety and of livelihood opportunities; and of negotiated meanderings within particular spaces of the Bellville central business district. Bellville's migrant networks become convivial when individuals innovatively sidestep away from tensions broiled in rhetoric of the "outsider" and instead negotiate space - both physical and social - to derive relations that often result in mutual benefits. This study also takes into consideration the greater international political and local socio- economic factors that drive migration, relationships and conviviality, and how they are intertwined in the everyday narrative of "insiders" and "outsiders" in Bellville. The Bellville central business district demonstrates the realities of interconnected local and global hierarchies of citizenship and belonging and how they emerge in a world of accelerated mobility. Ethnographic research in Bellville further demonstrates how the emergence of conviviality in everyday public life represents a critical field for contemplating contemporary notions of human rights, citizenship and belonging

Effects of restoration on Midwestern oak savanna biodiversity, structure, and oak regeneration

Over the last century, savannas throughout the world have been encroached by woody plants, altering over- and understory plant composition and distributions of understory resources. This dissertation investigates woody encroachment removal from Midwestern oak savannas, using a large-scale restoration experiment in Iowa. Four sites received a woody encroachment removal treatment (restoration) and four sites were retained as encroached controls. Chapter two details impacts on woody plant regeneration dynamics. Encroachment removal restored savanna canopy structure and overstory dominance by Querucs (oak) species; however, advanced regeneration was dominated by encroaching species within three years. I suggest that the encroached savannas represent an alternative stable state and that further management actions, potentially involving prescribed fire, will be necessary to maintain the savanna state.;Chapter three investigates spatiotemporal effects of encroachment removal on understory biodiversity. Restoration sites had increased alpha (within sample) Simpson\u27s diversity and alpha and gamma (site-level) species richness relative to control sites, while gamma and beta (among-sample) Simpson\u27s diversity, beta richness, and alpha species evenness were not affected. These changes were driven by widespread establishment of new species at the site-level (notably graminoids) and within-site proliferation of pre-existing species (predominantly graminoids and woody species). I highlight the utility of restoration experiments, like this one, for conducting research on multi-scale processes, such as species diversity.;Chapter four assesses development of understory resource and vegetation gradients. I found that encroachment removal restored light and soil moisture gradients and that these gradients were important for structuring post-restoration plant communities. The savannas in this study appear to be remarkably resilient to degradation, as important biophysical gradients were reestablished within years of restoration, even after decades of encroachment. These results are encouraging for future restoration at these sites and for woody encroachment removal efforts elsewhere.;Chapter five determines impacts of encroachment removal on patterns of Quercus alba (overstory dominant tree species) seedling success. Seedlings had greater survival and growth parameters in treatment sites, with generally better performance at further distances from trees. Thus, the mesic savannas in this study appear inherently unstable, as seedling recruitment is promoted in inter-canopy gaps. These results further support chapter two\u27s conclusion that the encroached savannas represent an alternative stable state

Structure of cytochrome a3-Cua3 couple in cytochrome c oxidase as revealed by nitric oxide binding studies

The addition of NO to oxidized cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) causes the appearance of a high-spin heme electron paramagnetic resonance (EPR) signal due to cytochrome a3. This suggests that NO coordinates to Cu{a3}+2 and breaks the antiferromagnetic couple by forming a cytochrome a3+3-Cu{a3}+2-NO complex. The intensity of the high-spin cytochrome a3 signal depends on the method of preparation of the enzyme and maximally accounts for 58% of one heme. The effect of N3- on the cytochrome a3+3-Cu{a3}+2-NO complex is to reduce cytochrome a3 to the ferrous state, and this is followed by formation of a new complex that exhibits EPR signals characteristic of a triplet species. On the basis of optical and EPR results, a NO bridge between cytochrome a3+2 and Cu{a3}+2 is proposed-i.e., cytochrome a3+2-NO-Cu{a3}+2. The half-field transition observed at g = 4.34 in the EPR spectrum of this triplet species exhibits resolved copper hyperfine splittings with |A{}| = 0.020 cm-1, indicating that the Cu{a3}+2 in the cytochrome a3+2-NO-Cu{a3}+2 complex is similar to a type 2 copper site

Encouraging Productive Behavior in Student Teams with Interventions

Teamwork pedagogies are used for teaching and learning in sociology, addressing general education goals, and developing students’ professional skills. Nevertheless, problems arise in group work that negatively affect learning, engagement, treatment of others, and team satisfaction. An intervention was added to an Introduction to Sociology course with an established teamwork pedagogy to improve these outcomes. We compared the results of student surveys before and after the intervention, finding improvement in students’ satisfaction with teamwork and students’ perceptions of their teammates. There were large, statistically significant improvements in interactional fairness. Students’ perceptions of learning improved, although the gains were not statistically significant. We theorize that the intervention improved the psychological safety climate for students, resulting in attitudes and dispositions that benefited social interactions in their teams. Our study demonstrates that faculty can encourage productive behavior in student teams with carefully crafted interventions

Cytochrome b559 of photosystem II

Continua com: Anuari estadístic de la ciutat de BarcelonaDigitalitzat per Artypla

Insights into substrate binding to the oxygen-evolving complex of photosystem II from ammonia inhibition studies

© 2014 American Chemical Society. Water oxidation in Photosystem II occurs at the oxygen-evolving complex (OEC), which cycles through distinct intermediates, S0-S4. The inhibitor ammonia selectively binds to the S2 state at an unresolved site that is not competitive with substrate water. By monitoring the yields of flash-induced oxygen production, we show that ammonia decreases the net efficiency of OEC turnover and slows the decay kinetics of S2 to S1. The temperature dependence of biphasic S2 decay kinetics provides activation energies that do not vary in control and ammonia conditions. We interpret our data in the broader context of previous studies by introducing a kinetic model for both the formation and decay of ammonia-bound S2. The model predicts ammonia binds to S2 rapidly (t1/2 = 1 ms) with a large equilibrium constant. This finding implies that ammonia decreases the reduction potential of S2 by at least 2.7 kcal mol-1 (\u3e120 mV), which is not consistent with ammonia substitution of a terminal water ligand of Mn(IV). Instead, these data support the proposal that ammonia binds as a bridging ligand between two Mn atoms. Implications for the mechanism of O-O bond formation are discussed

Electron spin relaxation of CuA and cytochrome a in cytochrome c oxidase: comparison to heme, copper, and sulfur radical complexes

Journal ArticleThe method of continuous saturation has been used to measure the electron spin relaxation parameter T1T2 at temperatures between 10 and 50 K for a variety of S = % species including: CuA and cytochrome a of cytochrome c oxidase, the type1 copper in several blue copper proteins, the type 2 copper in laccase, inorganic Cu(I1) complexes, sulfur radicals, and low spin heme proteins. The temperature dependence and the magnitude of T1T2 for all of the species examined are accounted for by assuming that the Van Vleck Raman process dominates the electron spin-lattice relaxation