Doctorat en sciences politiques / info:eu-repo/semantics/nonPublished

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The Compact Airborne Spectrographic Imager (CASI) and the satellite Moderate Resolution Imaging Spectroradiometer (MODIS) provide detailed information about the environment U.S. Naval forces choose to operate in. In recent years environmental conditions have been a driving factor in preventing the detection of underwater objects like mines. Suspended sediments are an environmental condition of interest. Remote sensors provide an opportunity to detect suspended sediments in a region prior to the commencement of operations and better prepare the force while reducing time required to complete operations. Monthly data sets collected using MODIS, from February 2005 to February 2006 show variations in weather patterns in the Mississippi Bight that cause the persistent presence of suspended sediments in certain areas of the Mississippi Bight. Major storm events such as hurricanes alter the location that suspended sediments persist in this region during the hurricane season. MODIS with 250m-pixel resolution is capable of detecting large-scale suspended sediment plumes while CASI with 1m-pixel resolution is capable of detecting very fine suspended sediment filaments as well as providing early warning of possible mine locations. As the mine warfare fleet diminishes in size, CASI and MODIS coupled with current sensors may provide an increase in detection capability while reducing the workload of mine detection ships. Continued research and study of suspended sediment transport during hurricane seasons may provide more information about how the environment changes.

M.A. / This project examines the phenomenon of subcontracting as it occurs in the gold mining industry in South Africa. The point of departure for the researcher is that subcontracting is not something totally new in the gold mining industry. What seems to be new is the manner in which it is currently used and this could be attributed to variety of factors, which have made reliance on permanent workforce not viable for the employers. Downscaling and large-scale retrenchments have become the order of the day. This happens at a time when there is an unprecedented increase in the number of subcontract workers. This has raised concerns among organised labour who, feel that such form of atypical employment is meant to undermine the gains of the labour movement has gained over the years. Such perception is made even more real by the decline in labour standards. Contractors actively discourage their employees from joining trade unions. Subcontract workers are paid wages as low as R700 a month, while they are forced to work under dangerous conditions. Their terms of contracts are unilaterally changed without any consultation and they can be easily dismissed without any warning, in some cases dismissed for being injured at work. Tensions mount between subcontract and permanent workers as the latter view the former as a threat to their job security. All this makes subcontracting an interesting area of study and this is even made more so by the fact that little has been done to investigate subcontracting in South Africa's gold mines. / Prof. Peter. Alexander

The walls of the old mine Kiesberg (Oravita, S-W Romania) of auriferous sulphides are supplied by rain water that percolate from the surface. Various microbial associations live on these walls. The life of these consortia is based on the sulphide oxidation ; this oxydation leads to the precipitation of oxidized mineral compounds (iron hydroxides, jarosite, amorphic aluminium compounds) that are accumulated in large quantities at the living cell exterior. In order to understand how these micro-ecosystems work and induce the genesis of the mineral deposit, a microbial inventory has been done (classic techniques and genetic methods), and the evolution of the microorganism population has been followed in parallel with the solution chemistry. The temporal and spatial relationships between the minerals and the organisms have been established with the help of macroscopic and microscopic observations by using electron microscopy (TEM ; SEM ; CRYO- SEM). / Les parois de l'ancienne mine d'or de Kiesberg (Oravita, SO Roumanie), alimentées par les eaux météoriques qui percolent par les microfissures, sont colonisées par des consortiums microbiens diversifiés. Leur fonctionnement repose sur la chimiolithoautotrophie, impliquant l'oxidation de minéraux, essentiellement des sulfures abondants dans la roche, d'ou la formation de différents composés minéraux (hydroxydes de fer, jarosite, composés alumineux amorphes) qui se déposent à l'extérieur des cellules vivantes et forment des accumulations de divers types. Comprendre le fonctionnement de ces microécosystèmes et la génèse des dépôts minéraux induits nécessitait un inventaire microbiologique (techniques classiques et méthode génétique), le suivi au cours du temps des populations des microorganismes en parallèle avec la chimie des solutions, et l'établissement des rapports spatiaux et temporels entre minéraux et organismes, nécessitant des observations macroscopiques et microscopiques par l'utilisation de la microscopie électronique (MET, MEB-EDS, CRYO-MEB).

PhD, Faculty of Engineering, University of the Witwatersrand