3 resultados para Bio metric modes

em SAPIENTIA - Universidade do Algarve - Portugal


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Taking up Hopkins and Dixon’s (2006) call to attend to the micro-politics of everyday constructions of space and place, which necessarily involves psychological concepts such as identity, belonging and attachment, this paper aims to show how a critical socio-cognitive approach to discourse analysis is an effective means of unpacking the ways in which versions of place are (re)produced and negotiated through discursive practices, and in particular the ways in which ‘legitimate’ collective identities are constructed in relation to place. I focus on the contemporary social phenomenon of lifestyle migration. Within Europe, this typically involves relatively affluent northern Europeans moving to destinations in southern Europe that are strongly linked to tourism. Although lifestyle migrants are generally viewed by their hosts as ‘desirable’ migrants due to their perceived economic and socio-cultural capital, their integration into destination communities is often minimal. The question arises as to how these migrants construct modes of belonging in relation to their adopted home-place and how they relate to the other social groups with whom they share it. Using texts from a variety of sources, including in-depth interviews with British migrants in Portugal, I explore not only how migrants position themselves (and others) discursively in relation to places, but also how they are already positioned by discursive practices in the public sphere. I also examine to what extent the construction of a ‘legitimate’ mode of belonging involves the construction of intergroup cooperation within that place.

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Tese de dout., Ciências Biotecnológicas (Biotecnologia Ambiental), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2010

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This work describes the synthesis of nanosized metal sulfides and respective SiO2 and/or TiO2 composites in high yield via a straightforward process, under ambient conditions (temperature and pressure), by adding to aqueous metals a nutrient solution containing biologically generated sulfide from sulfate-reducing bacteria (SRB). The nanoparticles‘ (NPs) morphological properties were shown not to be markedly altered by the SRB growth media composition neither by the presence of bacterial cells. We further extended the work carried out, using the effluent of a bioremediation system previously established. The process results in the synthesis of added value products obtained from metal rich effluents, such as Acid Mine Drainage (AMD), when associated with the bioremediation process. Precipitation of metals using sulfide allows for the possibility of selective recovery, as different metal sulfides possess different solubilities. We have evaluated the selective precipitation of CuS, ZnS and FeS as nanosized metal sulfides. Again, we have also tested the precipitation of these metal sulfides in the presence of support structures, such as SiO2. Studies were carried out using both artificial and real solutions in a continuous bioremediation system. We found that this method allowed for a highly selective precipitation of copper and a lower selectivity in the precipitation of zinc and iron, though all metals were efficiently removed (>93% removal). This research has also demonstrated the potential of ZnS-TiO2 nanocomposites as catalysts in the photodegradation of organic pollutants using the cationic dye, Safranin-T, as a model contaminant. The influence of the catalyst amount, initial pH and dye concentration were also evaluated. Finally, the efficiency of the precipitates as catalysts in sunlight mediated photodegradation was investigated, using different volumes of dye-contaminated water (150 mL and 10 L). This work demonstrates that all tested composites have the potential to be used as photocatalysts for the degradation of Safranin-T.