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Sample records for witwatersrand

  1. Physiology, University o/the Witwatersrand Zool. afro 4

    African Journals Online (AJOL)

    Department 0/ Physiology, University o/the. Witwatersrand. Accepted: July, 1976. INTRODUCTION. The effects of capture and transportation on freshwater fish have been studied by many workers (Fujiya 1961; Bouck & Ball 1966; Mann. 1965; Narasimhan & Sundararay 1971; Hattingh. & Van Pletzen 1974, to name but a ...

  2. The Origins of Forced Labor in the Witwatersrand

    Science.gov (United States)

    Moeti, Moitsadi

    1986-01-01

    Gold mining brought a forced labor system to Witwatersrand, South Africa, in the 1880s as African laborers were rounded up from the hinterland and delivered to the mines. The system produced low wages, high mortality, and the loss of chances for upward mobility. Forced labor persists today in South African mines. (VM)

  3. The Early Years of the University of the Witwatersrand Medical ...

    African Journals Online (AJOL)

    1973-01-20

    Jan 20, 1973 ... Witwatersrand Medical School and its Students*. G. R. BEATON, M.B. B.CH. UNIV. .... sion to South African universities, and to travel to. Europe became the .... provement of the residence food at the Queen Victoria. Hospital.

  4. Pyrite in the Mesoarchean Witwatersrand Supergroup, South Africa

    OpenAIRE

    2012-01-01

    Ph.D. Petrographic, chemical and multiple sulfur isotope analyses were conducted on pyrite from argillaceous, arenaceous and rudaceous sedimentary rocks from the Mesoarchean Witwatersrand Supergroup. Following detailed petrographic analyses, four paragenetic associations of pyrite were identified. These include: 1) Detrital pyrite (derived from an existing rock via weathering and/or erosion). 2) Syngenetic pyrite (formed at the same time as the surrounding sediment). 3) Diagenetic pyrite (...

  5. Witwatersrand Water Ingress Project - Information Management System (WWIPIMS), South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Hild, S.; Sieste, M.; Barth, A.; Rudinskaya, J. [Beak Consultants GmbH, Freiberg (Germany); Croukamp, L.; Roos, M. [Council for Geoscience (CGS), Pretoria (South Africa)

    2006-07-01

    The Witwatersrand Water Ingress Project at the Council for Geoscience, South Africa (CGS) deals with an inventory, a risk assessment and the development of rehabilitation strategies for abandoned mining sites in the Witwatersrand Mining Basin. The main focus is the prevention of water ingress and to understand the future decanting scenario. An Information Management System consisting of both a relational database and an application for the Witwatersrand Water Ingress Project is established for accessing and managing all project-related data. This easy to use application makes the data available to all staff at the CGS via several modules as well as a GIS-component for accessing and querying spatial data. This will enable the scientists to derive further knowledge of the water flowing processes by directly using all of the existing up-to-date data. Many additional functions, such as the support for map printing on demand, extensive possibilities for inquiries, data import and export, diagrams and a GIS-viewer for spatial inquiries do complete the system. (orig.)

  6. Uranium mineralization of the Witwatersrand and Dominion Reef systems

    International Nuclear Information System (INIS)

    Simpson, P.R.; Bowles, J.F.W.

    1977-01-01

    Uranium-bearing minerals in the Witwatersrand and Dominion Reef sediments have been studied by ore microscopic, electron microprobe, fission track and neutron activation analytical methods to determine the controls of uranium mineralization. In the Dominion Reef, which represents a high-energy banket type of depositional environment, allogenic thorian uraninite occurs in hydraulic equivalence with allogenic pyrite, quartz and possibly also gold in the sediments which have uranium-thorium ratios between 3.1 and 5.6 indicating substantial amounts of thorium-rich resistate minerals. The Witwatersrand sediments have uranium-thorium ratios ranging between 7.1 and 19.6 indicating lesser amounts of resistates which is consistent with the lower-energy depositional environment. The proximal or nearshore deposits are of banket type but are distinguished from the Dominion Reef by the abundance of concretionary pyrite formed within the Basin and the presence of carbonaceous matter. The distal deposits formed at greater distance from the shoreline contain decaying organic material which has precipitated both uranium and gold from solution. Subsequent metamorphism has resulted in the formation of carbonaceous material bearing finely disseminated low-thorium pitchblende and a fine dissemination of gold associated with sulphides and arsenides. (author)

  7. Some developments in the extraction of gold from Witwatersrand ores

    International Nuclear Information System (INIS)

    Laxen, P.A.

    1975-01-01

    The extraction of gold from most ores of the Witwatersrand has been consistently high - approximately 95 per cent - for many years. The present high price of gold has stimulated research and development into potential improvements of the standard procedures. The occurrence of the gold and its association with other minerals is described briefly. The Witwatersrand reefs also contain uranium and pyrite, and some of the improvements to the standard gold-extraction process are associated with the recovery or concentration of one or both of these valuable constituents. For instance, the 'reverse-leach' process, in which acid treatment for the extraction of uranium precedes cyanidation, results in improved gold extraction. Some concentration techniques used on the present residues from cyanidation offer promise in improving the overall gold recoveries. Thucholite is an important carrier of residual gold, and its recovery from some residues by flotation appears to be economically justifiable. Wet high-intensity magnetic separation has given promising results, in the laboratory and on the pilot plant, for the recovery of both uranium and gold from a number of cyanide tailings. The benefits of gravity concentration and of the application of empirical modelling to the gold-extraction process have been demonstrated by a mining group. Some developments in instrumentation for control during cyanidation are discussed briefly [af

  8. The flotation of gold, uranium, and pyrite from Witwatersrand ores

    International Nuclear Information System (INIS)

    Lloyd, P.J.D.

    1981-01-01

    The Witwatersrand reefs contain gold, uranium, and pyrite in the following average concentrations: 0,001 per cent, 0,02 per cent, and 1,7 per cent respectively. The paper discusses the flotation of pyrite to produce a sulphide concentrate, reviews work done on the production of gold concentrates, discusses attempts to produce maximum concentrates, and closes with a review of processes for the simultaneous flotation of these three species. It is concluded that high recoveries of all three species can be achieved only if a rougher concentrate of perhaps 20 per cent of the feed (by mass) is produced, and it is suggested that reverse leaching (leaching before cyanidation) of this concentrate, followed by a cleaning flotation step for the recovery of the pyrite, would be more efficient than the routes employed at present [af

  9. Investigation of Witwatersrand uranium-bearing quartz-pebble conglomerates in 1944-1945

    International Nuclear Information System (INIS)

    Bourret, W.

    1981-01-01

    The paper discusses the results-both short- and long-term of a 1944 study undertaken by a team from the Manhattan Project (supported by the governments of Great Britain and Canada) to assess the potential for uranium occurrence in the Witwatersrand mining region of South Africa. Details are given on the methods used by the Manhattan team and the results of the sampling study and survey that the team conducted in South Africa. The findings for 23 mines that were surveyed in the Witwatersrand are documented. These mines were the major producing mines in the Witwatersrand region. The prior research that led the Manhattan Project administrators to concentrate efforts on the Witwatersrand is described. The history of uranium production in the Rand since the 1944 study is delineated. Tables show the findings of the sampling study in terms of various major mines. A graph is included to show the growth of uranium production in the Witwatersrand from the initiation of the first operation in 1952 to 1975

  10. Fluid inclusion study of the Witwatersrand gold-uranium ores

    International Nuclear Information System (INIS)

    Shepherd, T.J.

    1977-01-01

    Fluid inclusions, preserved in quartz pebbles of the uraniferous and auriferous Precambrian oligomictic conglomerates of the Witwatersrand Basin, provide a unique insight into the genesis of the ores. Using differences in inclusion characteristics in conjunction with intra- and inter-deformational textures for adjacent pebbles, a distinction is made between pre- and post-depositional inclusions. Excluding those related to subsequent brittle fracture, the former comprise five principal types; two of which are distinguished by the development of liquid carbon dioxide. Collectively they indicate a moderate to high pressure-temperature environment of vein quartz formation. Systematic variation in the relative abundance of these inclusion assemblages for different sections of the orefield demonstrates the importance of well-defined provenance areas or multiple entry points into the basins. A marked sympathetic relationship between uraniferous banket ores and the presence of vein quartz rich in liquid carbon dioxide inclusions, together with a corresponding antipathetic relationship for gold, strongly suggests separate sources for the metals. The temporal and spatial aspects of the association 'U-CO 2 ' also imply a uranium influx into the basin from discrete areas of the hinterland contemporaneous with the sediments. Post-depositional inclusions are subordinate and offer no support for the alternative epigenetic model and show only a later interaction of relatively cool circulating groundwaters. A discussion is given of the probable nature and origin of uranium in the source rocks and its mode of transportation. In conclusion, a proposal is made for the use of applied fluid inclusion research in the evaluation of and exploration for similar deposits. (author)

  11. The Paleo-environmental significance of the iron-formations and iron-rich mudstones of the Mesoarchean Witwatersrand-Mozaan Basin, South Africa

    OpenAIRE

    2009-01-01

    M.Sc. The Mesoarchean Witwatersrand and Pongola Supergroups of South Africa are the oldest, well preserved supracratonic successions worldwide. Various banded iron formation (BIF) and iron-rich mudstone units occur within the West Rand Group of the Witwatersrand Supergroup and the Mozaan Group of the Pongola Supergroup. A granular iron formation (GIF) occurs in a single unit in the Nconga Formation of the Mozaan Group. The Witwatersrand Supergroup and Mozaan Group have been lithostratigrap...

  12. Evidence of tidal processes from the lower part of the Witwatersrand Supergroup, South Africa

    Science.gov (United States)

    Eriksson, Kenneth A.; Turner, Brian R.; Vos, Richard G.

    1981-08-01

    A 1600-m succession of quartz arenites and associated shaley deposits comprising the Hospital Hill Subgroup at the base of the Witwatersrand Supergroup is considered to have been deposited largely under the influence of tidal processes. Facies analysis indicates that deposition occurred in the following environments: (1) marine shalf; (2) shallow subtidal to intertidal; (3) intertidal flat; and (4) tidal inlet. The presence of strong tidal currents implies that the Witwatersrand Basin was open to an ocean basin, at least during the early stages of its evolution. Palaeocurrent trends and isopach data suggest that this probably lay to the southwest, an area now occupied by the high grade Natal—Namaqua metamorphic belt. The contrast between the supermature quartz arenites of the Hospital Hill Subgroup and the overlying gold-bearing immature subgreywackes, feldspathic quartzites and conglomerates of fluvial origin is believed to be a function of tidal reworking of sediments.

  13. Ammonium in Witwatersrand reefs: a possible indicator of metamorphic fluid flow

    International Nuclear Information System (INIS)

    Meyer, F.M.

    1991-01-01

    Ammonium concentrations and NH 4 + /K ratios in the Kimberley Reef indicate chemical interaction with metamorphic fluids. The data, although preliminary, also suggests a gold-ammonium association in that higher gold levels are related to higher NH 4 + /K ratios. Samples from the Ventersdorp Contact Reef are also hydrothermally altered but no ammonium was detected. The low ammonium concentrations suggest that over-printing by NH 4 -bearing metamorphic fluids was negligible. From this it is concluded that chemically different fluid systems must have been operative, probably at different times, during Witwatersrand history. It appears, therefore, that ammonium geochemistry is potentially useful in the study of fluid flow and related gold (re)distribution in Witwatersrand reefs. 17 refs., 2 figs., 1 tab

  14. Mining seismicity in the Witwatersrand Basin: monitoring, mechanisms and mitigation strategies in perspective

    CSIR Research Space (South Africa)

    Riemer, KL

    2012-06-01

    Full Text Available legislation. 2 Geology and the Witwatersrand Basin The study of geology may well date back to the period around 370 BC when Theophratus (see K. L. Riemer et al. / J Rock Mech Geotech Eng. 2012, 4 (3): 228... of gold over a period of 120 years from the supracrustal rocks of the 230 K. L. Riemer et al. / J Rock Mech Geotech Eng. 2012, 4 (3): 228?249 Kaapvaal Craton now sees mining...

  15. Examples of possible movement of gold in solution in the Witwatersrand, Ventersdorp, and Transvaal systems

    International Nuclear Information System (INIS)

    Whiteside, H.C.M.

    1981-01-01

    Many South African geologists consider that gold especially, and probably uraninite, as well as other heavy minerals such as zircon, chromite, and diamond, are detrital in the Precambrian quartz-pebble conglomerates of South Africa. It is suggested here that solution of gold and its redeposition elsewhere may have played a part in its enrichment or impoverishment. Two examples of possible solution of gold are cited, and the lack of modern placers associated with auriferous Witwatersrand is briefly discussed

  16. Evaluation of respirable particle matter in gold mine tailings on the Witwatersrand

    International Nuclear Information System (INIS)

    Ojelede, M.E.; Annegarn, H.J.

    2007-01-01

    Within the Witwatersrand gold mining area of South Africa, wind-blown dust is a significant contributor to atmospheric air pollution brought to the fore with the reworking of old mine tailings. Approximately 40,000 hectares are covered with tailings in the Witwatersrand. Wind-erosion during late austral winter and early spring causes surfaces of these tailings to be exposed, particularly during higher wind speeds and in the absence of rainfall. Local residents complain as the surrounding areas experience unpleasant dust episodes. As a result of urban PM 10 and PM 2.5 respirable particulate matter, increased respiratory ailments, morbidity and mortality, and concerns about the health impacts of wind-blown mine tailings in South Africa have been reported. Since 1981, significant monitoring of dustfall has taken place on the Witwatersrand, however, characterization of the respirable fraction of gold mine tailings material and dustfall is lacking. This paper presented the results of a study that established the content of respirable particulate matter in exposed mine tailings and wind-blown dust, and their likely contributions to ambient air. The initial results of the particulate size distribution of material samples from tailings and dust deposits collected in ambient dustfall-monitors were provided. Particle size distributions from different deposit types include slimes and sand deposits, surface and core material, and wind-winnowed secondary deposits. Fractions of PM 10 in source and deposited material were also discussed. It was concluded that there was a significant fraction of PM 10 material in the mine tailings, and that further work to quantify the population exposure risk is needed. 11 refs., 1 tab., 6 figs

  17. A literature survey of the matallurgical aspects of minerals in Witwatersrand gold ores

    International Nuclear Information System (INIS)

    De Waal, S.A.

    1982-01-01

    This survey reviews the information in the literature on the auriferous rock formations in the Witwatersrand-Orange Free State gold-mining area, the gold-bearing horizons, and the mineralogy and petrography of the different ore types. The metallurgical aspects of the gold, silver, uranium, platinum-group elements, cobalt, nickel, copper, and chromite in these ores are examined and, on the strength of this information, a list is given of those problems in metallurgical extraction that are of a mineralogical nature. Finally, a number of research projects, aimed to support current research at the Council for Mineral Technology, are suggested

  18. A pre-burial adsorption model for the genesis of gold in the Witwatersrand

    International Nuclear Information System (INIS)

    Davidson, R.J.

    1990-01-01

    The chemistry related to the adsorption of gold and uranium onto algal biomass (activated carbon) is related to the genesis of the Witwatersrand. Detrital gold, together with cyanide solubilized as the stable aurocyanide complex. With the subsequent decomposition of the algal deposits, it is surmized that carbon-rich layers having adsorptive properties formed in the conglomerates. Under these conditions, gold (silver) in solution would be adsorbed selectively as the cyanide complex, together with uranium as the carbonate complex. The subsequent burial and compression of the gold-rich conglomerate with temperatures rising to about 400 degrees C would then have reduced the adsorbed gold to the metal in a single segregated gold-silver metal phase. An adsorption model would explain the very consistent trends in the gold-to-silver ratios of individual reefs in the Witwatersrand, which suggest an extensive hydrothermal system approaching isothermal equilibrium. Also, as gold grades increase, so silver grades generally decrease, indicating the sequential displacement of silver by gold as classically obtained with activated carbon. 11 refs., 2 figs., 1 tab

  19. Witwatersrand gold deposits formed by volcanic rain, anoxic rivers and Archaean life

    Science.gov (United States)

    Heinrich, Christoph A.

    2015-03-01

    The Witwatersrand Basin in South Africa is one of the best-preserved records of fluvial sedimentation on an Archaean continent. The basin hosts the worlds biggest gold resource in thin pebble beds, but the process for gold enrichment is debated. Mechanical accumulation of gold particles from flowing river water is the prevailing hypothesis, yet there is evidence for hydrothermal mobilization of gold by fluids invading the metasedimentary rocks after their burial. Earth's atmosphere three billion years ago was oxygen free, but already sustained some of the oldest microbial life on land. Here I use thermodynamic modelling and mass-balance calculations to show that these conditions could have led to the chemical transport and precipitation of gold in anoxic surface waters, reconciling the evidence for fluvial deposition with evidence for hydrothermal-like chemical reactions. I suggest that the release of sulphurous gases from large volcanic eruptions created acid rain that enabled the dissolution and transport of gold in surface waters as sulphur complexes. Precipitation of the richest gold deposits could have been triggered by chemical reduction of the dissolved gold onto organic material in shallow lakes and pools. I conclude that the Witwatersrand gold could have formed only during the Archaean, after the emergence of continental life but before the rise of oxygen in the Earth's atmosphere.

  20. Microprobe analyses of uranium and thorium in uraninite from the Witwatersrand, South Africa, and Blind River, Ontario, Canada

    International Nuclear Information System (INIS)

    Grandstaff, D.E.

    1981-01-01

    Microprobe analyses of uranium and thorium in uraninite grains from the Witwatersrand, South Africa, and Blind River, Ontario, reveal that although individual grains are fairly homogeneous, the assemblage of grains is quite heterogeneous. This heterogeneity appears to favor genetic concepts advocating a detrital, placer origin for the uraninite

  1. Seismic attribute analysis to enhance detection of thin gold-bearing reefs: South Deep gold mine, Witwatersrand basin, South Africa

    CSIR Research Space (South Africa)

    Manzi, MSD

    2013-11-01

    Full Text Available The gold-bearing Upper Elsburg Reef clastic wedge (UER) in the South Deep gold mine in the Witwatersrand basin (South Africa) hosts the highly auriferous basal conglomerate known as the Elsburg Conglomerate (EC) reef. The reef is less than 20 m...

  2. A lexicon of plants traded in the Witwatersrand umuthi shops, South Africa

    Directory of Open Access Journals (Sweden)

    V. L. Williams

    2001-09-01

    Full Text Available At least 511 medicinal plant species are traded commercially in 50 Witwatersrand  umuthi shops. The plants are listedalphabetically by genus and common (vernacular name. The orthographic vernacular names, as well as the orthographicvariations in these names, are incorporated into the list. Annotations include the plant family, the number of umuthi shopsstocking the species, the language of the common name, and the plant part traded. The plant family in the region which hasthe highest number of species and infraspecific taxa in trade is Liliaceae  sensu lato., followed in descending order by  Fabaceae, Asteraceae. Euphorbiaceae and Amaryllidaceae. Approximately 88.6% of the vernacular names are in Zulu. Themean number of umuthi shops per species is 12.3. ranging from 1 to 41. Three hundred and fifty three species (69.2% occurin the four northern provinces, and 23 species are listed as threatened on the Red Data List.

  3. "Now the African reigns supreme": the rise of African boxing on the Witwatersrand, 1924-1959.

    Science.gov (United States)

    Fleming, Tyler

    2011-01-01

    This essay explores the growth of boxing among the African populations on the Witwatersrand region of South Africa between 1924 and 1959. It details how the sport's jump in popularity with Africans paralleled migration to Johannesburg. Africans increasingly saw boxing as an activity and skill conducive with survival in this new environment, and thus the sport grew in popularity, stature, and skill-level amongst this emergent urban population. The essay further explores the various ways that the sport was disseminated and popularized during the era, thus detailing how the sport reached both the African masses and petit-bourgeois educated elite. As their presence in Johannesburg became more and more permanent, boxing came to encompass various meanings and ideals, such as notions of discipline, independence and civility, to these urban populations.

  4. Gamma ray fluorescence for in situ evaluation of ore in Witwatersrand gold mines

    International Nuclear Information System (INIS)

    Rolle, R.

    1979-01-01

    A system for quantitative in situ evaluation of ore in Witwatersrand gold mines was researched and subsequently developed. The principle of measurement is based on the excitation of gold K X-rays in rock face samples by the 88 keV gamma radiation from a Cadmium-109 radioisotope source. The X-rays and scattered radiation from the rock matrix are detected by a hyperpure germanium detector cooled by liquid nitrogen in a portable probe. In the fluorescence spectrum the intensity ratio of the gold Kβ peaks to their immediate scattered background is evaluated and quantitatively converted in the portable analyser to area concentration units. All aspects of the physical and instrumental measurement had to be investigated to arrive at a system capable of quantitative evaluation of trace concentrations in stope face ore samples. The parameters of spectrum evaluation were investigated from fundamental principles to allow quantitative assessment of different methods of peak evaluation for optimization of the method as a whole. The basic concepts of random signal processing times were developed together with new concepts of pileup parameters to allow a quantitative description of the data acquisition rate of a complete analog pulse processing system. With this foundation a practical measuring geometry and optimum values for signal processing time parameters, for detector size and for discriminator positions for spectrum evaluation could be determined. Parallel with the derivation of optimum measurement parameters went the development of instruments, their field testing and appraisal of the method. The development of the gamma ray fluorescence method has shown the potential of the method to serve as an ore valuation tool and to assist in the geological identification of strata in Witwatersrand gold mines

  5. The geochronology or uraniferous minerals in the Witwatersrand Triad; and interpretation of new and existing U-Pb age data on rocks and minerals from the Dominion Reef, Witwatersrand and Ventersdorp Supergroups

    International Nuclear Information System (INIS)

    Rundle, C.C.; Snelling, N.J.

    1977-01-01

    Uranium and lead analysis of rock samples from the Witwatersrand, Ventersdorp, and Transvaal supergroups give mainly discordant ages. Samples from the Upper Witwatersrand of the Orange Free State give 207 Pb/ 206 Pb ages of ca. 3000 Ma. These data when considered together with earlier total conglomerate U-Pb analyses from the Dominion Reef Supergroup lead to the conclusion that the uraniferous minerals of the Dominion Reef, Witwatersrand, Ventersdorp and Transvaal conglomerates are 3050 +- 50 Ma old. In the northern parts of the Witwatersrand Basin the parent uraniferous minerals experienced a major reworking at 2040 +- 100 Ma which brought about the partial or complete resetting of the original 3050 Ma age. Radiogenic lead released during this reworking crystallized as galena in veins and fissures which cut across the uraniferous conglomerate horizons. This reworking appears to have had little effect in the Orange Free State to the south. Its age and geographical extent suggest it was caused by thermal effects which accompanied the emplacement of the Bushveld Igneous Complex at 1950 +- 150 Ma. Samples from the South, which were relatively unaffected by the ca. 2040 Ma reworking generally show the effects of recent uranium loss. In the northern part of the basin discordant age patterns characteristic of lead loss have been imposed on uranium-lead systems which were generally reset (partially or completely) by the ca. 2040 Ma event. The presence of 3050 Ma old minerals in sedimentary sequences which are probably younger than ca. 2740 Ma suggest the simple interpretation that the uraniferous minerals are predominantly detrital. (author)

  6. A statistical analysis of mineral relationships in a Witwatersrand gold placer at Randfontein Estates

    International Nuclear Information System (INIS)

    Tucker, R.F.

    1983-01-01

    The Proterozoic 'Composite Reef' on the Randfontein Estates Gold Mine, is a proximal Witwatersrand braided-stream placer, in which pyrite, chromite, zircon, uraninite, and gold are the more common detrital minerals. They range in concentration from a few ppm to over 3 per cent. Optimum concentration of these minerals occurs on scour- and pebble-armoured surfaces, in conglomerate gravel bars, and in trough cross-bedded quartz-arenites. The distribution of gold is, however, complex and the relative proportions of the detrital minerals change from one depositional situation to another. The abundance of detrital and other related minerals was monitored geochemically and quantitatively indicates the prevalence of optimal placer concentration situations in preserved depositional subenvironments of the 'Composite Reef'. The relationships between 20 elements were determined by using an R-mode factor-analysis of the geochemical data. The elements load on to chalcophile, detrital oxide, hydrothermal and clay factors, suggesting the consanguinity of four subsets of elements. A multiple linear regression of gold against the other elements provides the framework for an improved prediction of gold where only very small or single samples are available. The method uses many elements in a single sample to achieve statistical reliability, as opposed to the geostatistical method where many samples of a single element are analysed. The regression equation demonstrates the geochemical validity of the geological-response model for optimum gold mineralization

  7. Uranium-thorium silicates, with specific reference to the species in the Witwatersrand reefs

    International Nuclear Information System (INIS)

    Smits, G.

    1987-01-01

    (U,Th)-silicates form two complete series of anhydrous and hydrated species with general formulae (U,Th)SiO 4 and (U,Th)SiO 4 .nH 2 O respectively. The end-members of the anhydrous series are anhydrous coffinite and thorite, and those of the hydrated series, coffinite and thorogummite. Although the silicates are relatively rare in nature, coffinite is a common ore mineral in uranium deposits of the sandstone type. In the Witwatersrand reefs, (U,Th)-silicates are extremely rare in most reefs, except for the Elsburg Reefs on the West Rand Goldfield and the Dominion Reef. In these reefs detrital uraninite has been partly or entirely transformed to (U,Th)-silicates of coffinite composition, but thorite and thorogummite of detrital origin are also found in the Dominion Reef. In leaching tests on polished sections of rock samples containing (U,Th)-silicates, a dilute sulphuric acid solution, to which ferric iron had been added, was used as the lixiviant. It appeared that the dissolution of coffinite is less rapid than that of uraninite and uraniferous leucoxene. However, the reaction of silicates of high thorium content is much slower, and was not completed during the tests

  8. Late Archaean tectonics and sedimentation of the South Rand area, Witwatersrand basin

    International Nuclear Information System (INIS)

    Spencer, R.M.

    1992-01-01

    The sedimentary fill of the southern part of the northeastern Witwatersrand basin consists of four unconformity bounded mega sequences. Early sedimentation took place in a stable, epi continental basin characterized by amphidromic flow. Gradual transgression to distal shelf facies was followed by gradual emergence to intertidal facies. Unconformity Bounded Mega sequence 2 shows that the basin underwent regression, in which discrete uplifts provided a source of granite-greenstone-derived sediment to associated braid plain aprons. Thereafter the basin subsided into a system almost identical to that in which Unconformity Bounded Mega sequence 1 developed. Unconformity Bounded Mega sequence 3 was deposited in a similar marine environment, on an angular unconformity in the east. Regional uplift occurred to the northwest of the basin. Unconformity Bounded Mega sequence 4 records progradation of a perennial braid plain controlled by uplift in the east, and by the minor influence of an uplift to the northwest. Rapid transgression resulted in submarine fan facies development, after which rapid emergence was controlled by uplift in the east, and to a lesser extent, the north. The braid plain was the site of extrusion of komatiitic lavas of the lower Ventersdorp Supergroup and was subsequently smothered by the sustained outpouring of a two kilometer-thick pile of basalts. Crustal extension climaxed after extrusion of felsic volcanics. This extension is antithetic to regional down-to-the-northwest, lower Ventersdorp Supergroup rifting. The last conspicuous phase of Precambrian tectonics is the superposition of a right-lateral wrench system on the early structural framework, after deposition of the lower Transvaal Sequence. Analysis of the samples was carried out by X-ray fluorescence spectrometry. 243 refs., 119 figs., 8 tabs

  9. Housing and population sprawl near tailings storage facilities in the Witwatersrand: 1952 to current

    Directory of Open Access Journals (Sweden)

    Melanie A. Kneen

    2015-11-01

    Full Text Available Mining, tailings storage facilities (TSFs, dust pollution and growth in residential housing development are synonymous with the Witwatersrand, South Africa. Encroachment of housing onto land close to TSFs, i.e. areas rendered marginal because of the dust hazard and risk of structural failure, has continued unabated for decades, intensifying human exposure to windblown mineral dust. Recent research indicates that the finer milling used for modern gold extraction results in aeolian dust emanating from the TSFs which contributes to a higher proportion of inhalable particles in the source material. Air quality dispersion modelling, validated by ambient aerosol monitoring campaigns, indicates that episodic dust events generate particulate matter (PM10 and, specifically, quartz dust concentrations that are unhealthy at distances of up to 2 km downwind from TSFs. This contribution documented residential development from 1952 to 2011 (using historical aerial photographs, census data from 2001 and 2011 and ancillary information to determine the population exposed to dust emanations from the TSFs. Using the images, land use was classified into residential areas, TSF footprints and open areas, onto which a series of 500 m buffer zone contours were superimposed. The resulting statistics were used to assess the populations exposed to dust hazard within the defined buffer zones. Overall, housing development has experienced a growth of approximately 700% since 1952 at a rate of 14% per year. Analysis of recent monitoring campaign data has confirmed multiple occurrences of quartzrich inhalable dust in residential settings at levels that exceed occupational health standards, extrapolated to values for population exposure.

  10. Chemistry and palynology of carbon seams and associated rocks from the Witwatersrand goldfields, South Africa

    Science.gov (United States)

    Ebert, L.B.; Robbins, E.I.; Rose, K.D.; Kastrup, R.V.; Scanlon, J.C.; Gebhard, L.A.; Garcia, A.R.

    1990-01-01

    Carbon seams in the Witwatersrand System of South Africa host some of the richest gold concentrations in the world. A study of the microscopic characteristics in thin sections and acid residues, and of the chemical and physical nature of the carbon-bearing phases, was undertaken to gain some understanding of the biological precursors and thermal changes that have occurred since the seams were buried. The HClHF acid-resistant organic tissues in this Early Proterozoic coal are filamentous and spherical, which are typical morphologies for microorganisms. The tissues are carbonized black as would be expected for metamorphic rocks, so usual palynological techniques were of limited use. Therefore, the chemical and physical nature of the organic remains was studied by H C ratios, X-ray diffraction (XRD), 13C nuclear magnetic resonance (NMR), reductive chemistry, crosspolarization/magic angle spinning NMR (CP/MAS), and electron spin resonance (ESR). The H C ratios of the samples examined are similar to those of semi-anthracite and petroleum cokes from delayed cokers. XRD shows graphite is not present and that the gold is in elemental form, not chemically bound or intercalated between carbon planes. NMR shows that both aromatic and paraffinic carbons are present. Integration of the carbon NMR spectra suggests that 80% of the carbon is sp2-hybridized and 20% is sp3-hybridized. Reductive chemistry shows that the benzenoid entities are larger than common polynuclear aromatic hydrocarbons such as perylene and decacyclene. Dipolar dephasing CP/MAS NMR suggests the presence of two types of paraffinic carbons, a rigid methylene group and a rotating methyl group. The narrowing of the ESR linewidth between room temperature and 300??C shows that the materials examined have not previously been subjected to temperatures as high as 300??C. ?? 1990.

  11. Micro-PIXE analysis of varied sulfide populations from the Ventersdorp Contact Reef, Witwatersrand Basin, South Africa

    Science.gov (United States)

    Reimold, W. U.; Przybylowicz, W.; Koeberl, C.

    1999-10-01

    Micro-PIXE spot analysis and true elemental imaging of pyrrhotite and pyrite crystals from the Ventersdorp Contact Reef (VCR) of the Witwatersrand basin, the world's most important gold resource, are reported. The objective was to evaluate the use of this technique with regard to its analytical resolution concerning the detection limits for the elements encountered in these samples and their spatial distribution. Furthermore, this project was designed to identify chemical signatures characteristic for particular textural types of VCR sulfides. Micro-PIXE is indeed a highly useful technique for the analysis of such materials and provided results that could not be obtained by optical and SEM microscopy and electron probe microanalysis (EPMA). Micro-inclusions could be made visible through elemental area scanning. Chemical zonation in the interior of apparently homogeneous grains was detected, which has obvious implications for the interpretation of the multi-stage evolution of Witwatersrand mineralization. The available data do not yet allow unambiguous chemical classification of different sulfide types (generations), but a distinct late growth of As-enriched sulfide was detected. These late overgrowths may be enriched in Ni or not. No unambiguous relation between As and Au could be observed in these samples.

  12. Advances in geophysical technologies for the exploration and safe mining of deep gold ore bodies in the Witwatersrand basin, South Africa

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-08-01

    Full Text Available -1 Proceedings of the Twelfth Biennial Meeting of the Society for Geology Applied to Mineral Deposits, Uppsala, Sweden, 12-15 August 2013 Advances in geophysical technologies for the exploration and safe mining of deep gold ore bodies in the Witwatersrand...

  13. The distribution of radioelements in archaean granites of the Kaapvaal Craton, with implications for the source of uranium in the Witwatersrand Basin

    International Nuclear Information System (INIS)

    Robb, L.J.; Meyer, M.; Ferraz, M.F.; Drennan, G.R.

    1989-05-01

    Approximately 500 samples from the Archaean granitic basement of the southern Kaapvaal Craton have been analysed, for U and Th. When viewed in conjunction with geological relationships, the radioelement distribution patterns in the Archaean basement provide contraints regarding the origin of uranium in the Witwatersrand Basin. Granites in the Baberton region are sub-divided into three magnetic cycles, the earliest cycle comprising tonalite-trondhjemite gneisses, the intermediate cycle comprising literally extensive K-rich batholiths and the final stage consisting of discrete intrusive granitic plutons. Uranium and thorium contents vary as a function of age and rock type, an increase progressively from the first cycle through to the third cycle. Certain of the late granite plutons may have been S-type in origin, have relatively low Th/U ratios, high U contents, and are characterized by accessory minerals dominated by monazite-like phases. The late granite plutons with highest radioelement contents appear to have formed circa 2,8 Ga, an age which coincides with granulite facies metamorphism and uranium-thorium depletion in the lower crust, as recrorded in the Vredeford crustal profile. Uranium has been leached from portions of the regolith profile, but also concentrated into leucoxene-rich zones derived from the breakdown of pre-existing titanium-bearing phases. The widespread development of an uraniferous leucoxene protore in weathered source rocks of the Witwatersrand Basin has relevance to the genesis of authigenic U-Ti phases (brannerite) in the reefs themselves. The study of radioelement distribution in Archaean granites adjacent to the Witwatersrand Basin provides a framework within which considerations regarding the origin of the uranium deposits in the basin can be viewed. The secular evolution of the Archaean granitic basement, hydrothermal processes, and palaeoweathering all played a role in the formation of the Witwatersrand deposits

  14. Multiscale organisation of organic matter associated with gold and uranium minerals in the Witwatersrand basin, South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Smieja-Krol, Beata; Duber, Stanislaw [Faculty of Earth Science, University of Silesia, 60 Bedzinska St., 41-200 Sosnowiec (Poland); Rouzaud, Jean-Noel [Laboratoire de Geologie, Ecole Normale Superieure, 24, rue Lhomond, 75231 Paris Cedex 5 (France)

    2009-03-01

    Organic matter from the northern part of the Early Proterozoic Witwatersrand basin (Carbon Leader reef) was investigated using optical (OM) and transmission electron (TEM) microscopes, completed by XRD analysis. The multiscale organization (texture, microtexture, structure) of the organic matter was observed in order to gain information about the processes which affected organic material after its deposition in sediments. In the micrometre scale (optical microscope), the shape and size of the Reflectance Indicating Surface (RIS) of the organic matter were determined. The organic matter reveals a prevailing biaxial symmetry. The size of RIS is generally dependent on uranium and increases with increasing uranium concentration. Furthermore, it appears that more than one RIS is present within the scale of a single sample, each with a different symmetry and size. The presence of domains differing in organisation of the aromatic framework was confirmed by TEM observation in the DF mode. The aromatic skeleton of organic matter is composed of short, often crumpled, mostly isolated (non-stacked) polyaromatic layers whose fringe length corresponds to 3-16 aromatic rings. The data indicate reorganization of the polyaromatic organic matter structure under stress in high pressure and relatively low temperature conditions. The organic matter was in a solid state within the rocks before the pressure event. (author)

  15. Wet high-intensity magnetic separation for the concentration of Witwatersrand gold-uranium ores and residues

    International Nuclear Information System (INIS)

    Corrans, I.J.; Levin, J.

    1979-01-01

    Wet high-intensity magnetic separation (WHIMS) for the concentration of gold and uranium was tested on many Witwatersrand cyanidation residues, and on some ores and flotation tailings. The results varied, but many indicated recoveries of over 60 per cent of the gold and uranium. The main source of loss is the inefficiency of WHIMS for material of smaller particle size than 20μm. The recoveries in the continuous tests were lower than those in the batch tests. The continuous tests indicated an operational difficulty that could be experienced in practice, namely the tendency for wood chips and ferromagnetic particles to block the matrix of the separator. It was decided that a solution to the problem lies in the modification of the separator to allow continuous removal of the matrix for cleaning. A system has been developed for this purpose and is being demonstrated on a pilot-plant scale. Promising results were obtained in tests on a process that combines a coarse grind, gravity concentration, and WHIMS. In the gravity-concentration step, considerable recoveries, generally over 50 per cent, of high-grade pyrite were obtained, together with high recoveries of gold and moderate, but possibly important, recoveries of uranium. A simple model describing the operation of the WHIMS machine in terms of the operating parameters is described. This should reduce the amount of empirical testwork required for the optimization of operating conditions and should provide a basis for scale-up calculations. The economics of the WHIMS process is discussed [af

  16. Detrital gold, uranium, and pyrite concentrations related to sedimentology in the precambrian Vaal Reef placer, Witwatersrand, South Africa

    International Nuclear Information System (INIS)

    Minter, W.E.L.

    1976-01-01

    This study integrates stratigraphical, structural, petrological, and mineralogical data with a comprehensive set of sedimentological data to synthesize a model that describes the genesis of the Vaal Reef placer. Results show that the Vaal Reef placer was a shoreline feature of the Upper Witwatersrand Basin and that its deposition was controlled, firstly, by the major structure of the basin and, secondly, by a minor transverse synclinal structure that induced an entry point. New geological aspects that have emerged are, firstly, that the tectonic framework during Vaal Reef Stage deposition was very much simpler than previously envisaged. There is no evidence of subsidiary incipient basining. Secondly, modifications of previous conceptual models are made which emphasize the importance that detailed dispersal patterns and subtle paleosurface forms had on heavy mineral distribution in the distal fluviodeltaic environment of carbon-seam placers. Thirdly, sedimentary responses involving unconformities, disconformities, and accumulation are evidently related to particular entry points and may not be specifically correlated beyond their local tectonic framework. Fourthly, tectonic instability and basining is dated between Lower and Upper Ventersdorp System time and certainly before deposition of the Transvaal System

  17. Distribution, ecology and inhibition of Thiobacillus ferrooxidans in relation to acid drainage from Witwatersrand gold mine dumps

    International Nuclear Information System (INIS)

    Whillier, P.A.

    1987-03-01

    The distribution and ecology of Thiobacillus ferrooxidans in gold mine dumps and possible means for its inhibition were investigated. A literature survey of the micro-ecology of mine waste dumps in various parts of the world was undertaken. A linear alkylbenzene sulphonate (LAS), NANSA 80/S, and a cetyl pyridinium chloride, Ceepryn, were tested as possible inhibitors for mine dump application. The LAS was rejected because it is poorly soluble in water and required higher concentrations than SLS for the inhibition of T.ferrooxidans. Ceepryn was an efficient inhibitor, but its efficiency was dramatically impeded in the presence of mine dump sand making it unsuitable for application on dumps. The SLS and LAS were tested against a mixed population of T.ferrooxidans from gold mine dumps and these bacteria were shown to be marginally more resistant to the inhibitors than the pure T.ferrooxidans culture. Sampling from mine dumps on the Witwatersrand suggested that the major T.ferrooxidans populations occurred in the moist sand of the drainage areas at the base of dumps, with few viable iron-oxidising bacteria located on the surfaces or in the centre of dumps. Sites of low moisture in dumps contained few or no viable bacteria. In the laboratory the bacterial viability decreased rapidly with loss of moisture from the sand. Moisture was shown to be important to bacterial activity and should be considered with respect to acid drainage control. Experimental sand columns showed that iron was leached with water from mine dump sand in the absence and presence of bacteria. In this study substrates, moisture, oxygen and carbon dioxide availability, ph, temperature, microorganisms and metal pollutants of uranium waste dumps are also covered

  18. Characterization of active members in C and N cycles in the subsurface environment of the Witwatersrand Basin

    Science.gov (United States)

    Lindsay, M. R.; Lau, C. M.; Tetteh, G.; Snyder, L.; Kieft, T. L.; Lollar, B. S.; Li, L.; Maphanga, S.; van Heerden, E.; Onstott, T. C.

    2012-12-01

    Fracture fluid from various depths and locations in Beatrix gold mine (Gold Fields Ltd.), located in the Welkom region on the 2.9 Ga Witwatersrand Basin of South Africa has been previously studied. Research has shown differential geochemistry data and distinctive community structure which varies from the dominance of different Proteobacterial classes in waters with paleometeoric 18O and 2H signatures including methanotrophs to one dominated by Firmicutes including Candidatus Desulforudis audaxviator-like taxa, which are associated with more saline waters with high concentrations of dissolved H2, hydrocarbons from water-rock reaction and 18O and 2H signatures above the Global Meteoric Water Line. Archaea seem to be a minority and all are euryarchaeota including methanogenic genera. The question is:Which of them are actively driving the subsurface C and N cycles? At shaft 3 on level 26, 1.3 kmbls, fracture water from 42 m behind the tunnel wall located in the Main quartzite formation was collected and analyzed. The temperature, pH, Eh, dissolved O2 and salinity of this hydrocarbon-containing fracture water ranged from 35 to 38°C, 8.2 to 8.8, -30 to -100 mV, 0.3 to 30 μM and 4.2 to 4.3 ppt, respectively. Gas comprised 60% CH4 and 20% N2. The same fracture formerly yielded Halicephalobus mephisto, the first reported subsurface nematode. Microorganisms were captured on filters in two field seasons. Defined by 16S rDNA, 2011 January sample contains β-Proteobacteria (50%), Firmicutes (39%) and α- and γ-Proteobacteria (7%). Of the Firmicutes, 90% were represented by Ca. D. audaxviator. All archaea detected are closestly related to sequences also reported from South African gold mines, with Crenarchaeota accounting for 77% of the clones. Prospective methane-oxidation and production were assessed by amplifying genes encoding for particulate methane monooxygenase alpha subunit (pmoA) and methyl-coenzyme M reductase alpha subunit (mcrA). PmoA genes of Type II

  19. Mineralogy and geochemistry of phosphate minerals and brannerite from the Proterozoic Carbon Leader Reef gold and uranium placer deposit, Witwatersrand, South Africa

    International Nuclear Information System (INIS)

    Oberthuer, T.

    1987-01-01

    Yttrium-phosphate, the most common phosphate phase, is closely associated with detrital uraninite. It is assumed having formed by the reaction of mobile phosphate with Y and HREE liberated from the lattice of detrital uraninite, during diagenesis and/or metamorphism of the sediments. Authigenic brannerite (UTi 2-3 O 6-8 ) is well-defined microscopically and geochemically. Textural relationships indicate that both titanium migrated to uraninite, forming brannerite, and mobile uranium caused the 'branneritization' of rutile/leucoxene. Microprobe analyses demonstrate that brannerite from the Carbon Leader Reef displays a distinct and small variation of UO 2 /TiO 2 ratios, which lie close to the theoretical value of 1.117 for UTi 3 O 8 , in contrast to uraniferous leucoxene/brannerite from other Witwatersrand-type deposits, the latter showing a wide scatter of UO 2 /TiO 2 ratios. (orig./HP)

  20. The application of a Business Intelligence tool for strategic planning in a higher education institution: a case study of the University of the Witwatersrand

    Directory of Open Access Journals (Sweden)

    Vincent Nyalungu

    2011-07-01

    Full Text Available This article presents a discussion on the importance of business intelligence (BI and the role that a specific BI tool, Business Intelligence Enterprise Edition, plays in the strategic decision-making processes in an organisation. The University of the Witwatersrand, often referred to as Wits, was used as a case study. The main objective of a business intelligence tool is to improve the quality and timeliness of the input of data to the organisational decision-making process. The quality of the data, which is an organisational asset, is therefore of the utmost importance. Approaches for the identification of business intelligence from corporate information and knowledge management were also assessed. A questionnaire was administered among key informants within the university in order to address some of the pertinent issues at higher education institutions. In addition, the role of a data warehouse within the business intelligence framework was presented. The paper itself covers a wide range of disciplines from information technology, knowledge management to decision sciences. The article also presents a proposed framework to be used in line with the best practices in the implementation of business intelligence solutions. Keywords: Business Intelligence (BI, Business Intelligence Enterprise Edition (BIEE, Data Warehouse, Strategic Decision Making, Strategic Planning, Higher Education Institutions and Knowledge Management. Disciplines: Information Technology, Knowledge Management, Management Sciences, Decision Sciences & Management

  1. The history and composition of the Raymond A. Dart Collection of Human Skeletons at the University of the Witwatersrand, Johannesburg, South Africa.

    Science.gov (United States)

    Dayal, Manisha R; Kegley, Anthony D T; Strkalj, Goran; Bidmos, Mubarak A; Kuykendall, Kevin L

    2009-10-01

    The Raymond A. Dart Collection of Human Skeletons (Dart Collection) is housed in the School of Anatomical Sciences at the University of the Witwatersrand, Johannesburg, South Africa, and comprises one of the largest documented cadaver-derived human skeletal assemblages in the world. This collection originated in the early 1920s as a result of the efforts of Raymond Dart and continues to grow. The skeletons included represent varied indigenous and immigrant populations from southern Africa, Europe and Asia. This contribution documents the history of the collection and provides an updated inventory and demographic assessment of this valuable research collection. According to a recent inventory the Dart Collection currently comprises 2,605 skeletons representing individuals from regional SA African (76%), White (15%), Coloured (4%) and Indian (0.3%) populations. A large proportion of the skeletons (71%) represent males. The recorded ages at death range from the first year to over 100 years of age, but the majority of individuals died between the ages of 20 and 70. The Dart Collection has been affected by collection procedures based on availability. All of the cadavers collected before 1958, and large proportions subsequently, were derived from unclaimed bodies in regional South African hospitals. Some details of documentation (age at death, population group) are estimates and some aspects of the collection demographics (sex ratios) do not closely reflect any living South African population. Our inventory and analysis of the Dart Collection is aimed to assist researchers planning research on the materials from this collection.

  2. An investigation into the effects of various flotation parameters on the flotation behaviour of pyrite, gold and uranium contained in Witwatersrand type ores, and their practical exploitation

    International Nuclear Information System (INIS)

    Duchen, R.B.; Carter, L.A.E.

    1986-01-01

    The importance of copper sulphate, pH, conditioning time, grind, the intensity of agitation during conditioning, and the correct type of conditioning on the alkaline flotation of gold, uranium and pyrite from Witwatersrand type ores is shown. The peculiar 'run-away float' condition experienced at high pH with air agitated conditioning is presented. The best laboratory flotation results were obtained after 20 minutes of vigorous mechanical conditioning of the pulp at a pH of 11,8 with copper sulphate 100 g/t Aero promoter 3477 20 g/t, xanthate 80 g/t, frother 5 g/t, grind 68% in - 75 μm and pulp specific gravity of 1,280 (dry solids sp. gr. = 2,70). The practical implementation of the laboratory findings on the Hartebeestfontein No. 7 Shaft flotation plant resulted in an increase in gold recovery from about 76% to about 86%, and an increase in pyrite recovery from about 86% to about 92%

  3. The first joint congress of the South African Biochemical Society, South African Genetics Society and the South African Society for Microbiology at the University of the Witwatersrand, 29 June-4 July 1986

    International Nuclear Information System (INIS)

    1986-01-01

    The South African Biochemical Society, South African Genetics Society and the South African Society for Microbiology held a joint congress at the University of the Witwatersrand from 29 June - 4 July 1986. The papers delivered cover subjects such as Molecular biology, Genetics, Biochemistry, Medical biochemistry, Physiology, Zoology and Isotope and radiation sciences. Different isotopes are used in labelling studies of enzymes, nutrition, metabolism, viruses, bacteria and other biological assays done in the fields of Biochenmistry, Genetics and Microbiology. This work contains only the abstracts of these papers

  4. Investing in African research training institutions creates sustainable capacity for Africa: the case of the University of the Witwatersrand School of Public Health masters programme in epidemiology and biostatistics

    Science.gov (United States)

    2012-01-01

    Background Improving health in Africa is a high priority internationally. Inadequate research capacity to produce local, relevant research has been identified as a limitation to improved population health. Increasing attention is being paid to the higher education sector in Africa as a method of addressing this; evidence that such investment is having the desired impact is required. A 1998 3-year investment by the Special Programme for Research and Training in Tropical Diseases (TDR) in research training at the School of Public Health, University of the Witwatersrand, South Africa was reviewed to assess its' impact. Methods A descriptive cross-sectional survey of the 70 students registered for the masters programme in epidemiology & biostatistics from 2000-2005 was conducted. Data were collected from self-administered questionnaires. Results Sixty percent (42/70) of students responded. At the time of the survey 19% of respondents changed their country of residence after completion of the masters course, 14% migrated within Africa and 5% migrated out of Africa. Approximately half (47%) were employed as researchers and 38% worked in research institutions. Sixty percent reported research output, and four graduates were pursuing PhD studies. Government subsidy to higher education institutions, investments of the University of the Witwatersrand in successful programmes and ongoing bursaries for students to cover tuition fees were important for sustainability. Conclusions Investing in African institutions to improve research training capacity resulted in the retention of graduates in Africa in research positions and produced research output. Training programmes can be sustained when national governments invest in higher education and where that funding is judiciously applied. Challenges remain if funding for students bursaries is not available. PMID:22475629

  5. Senior Lecturer, School of Law, University of the Witwatersrand ...

    African Journals Online (AJOL)

    ... does not accord with the definition of an employee or an independent contractor or a ... is an employee when he does practical training for the benefit of the university. ... The Compensation for Occupational Injuries and Diseases Act makes it ...

  6. Characterisation of gold tailings dams of the Witwatersrand Basin ...

    African Journals Online (AJOL)

    2006-10-04

    Oct 4, 2006 ... bentonite layer between the 9th and 10th meter level to minimise vertical air flow from the bottom of the tailings dams. ... m depth with bentonite. Due to the age of the dams, and the fact that they ...... from Cyanide-Rich Gold Mine. Tailings. Unpublished M.Sc. Thesis, The University of New Bruns- wick, USA.

  7. The significance of mineralogical analysis of Witwatersrand plant products

    International Nuclear Information System (INIS)

    Koen, G.M.; Snegg, J.A.

    1978-01-01

    The ore processor must obtain knowledge of the mode of occurrence of the mineral or minerals he tries to recover in order to be able to improve the extraction process or to increase the grade of the residues. The mineralogist can supply this information, thereby 1) enabling the metallurgist to take steps to improve the efficiency of the plant, 2) enabling planning of a more efficient future plant for processing similar ores, or 3) assisting in the planning of metallurgical testwork. Examples of such investigations are 1) treatment of free gold in the recovery plant, 2) deportment of gold in residues, 3) recovery of gold from thucholite, and 4) quantitative determination of the deportment of uranium (or gold) in head and in residue samples

  8. Pressure leaching of uranium-bearing Witwatersrand ores

    International Nuclear Information System (INIS)

    Bovey, H.J.; Stewart, L.N.

    1979-01-01

    Since 1955 extensive pressure-leaching testwork has been conducted by Anglo American Research Laboratories (AARL) in laboratory-scale batch autoclaves. In 1958 a small continuous pilot-plant of 45 kg of solids per hour was operated by AARL. In 1974, when high uranium prices were anticipated, Anglo American, encouraged by successful commercial-scale autoclave operations as practised by Outokumpu, Sherritt Gordon, and Impala Platinium, decided to install a continuous pilot plant at Western Deep Levels. At that time the proposed pilot plant was considered to be of prototype size. The project was funded by members of the Nuclear Fuels Corporation (Nufcor). Since its commissioning in February 1977, the pilot plant at Western Deep Levels, which can treat between 10 and 20 tons of dry solids per hour, has been used to test ores from four different mines. The paper compares the uranium extractions and pyrite oxidation obtained in laboratory batch autoclaves with those obtained in the continuous pilot plant. In general, differences in uranium extraction are not great and can be explained; the differences in pyrite oxidation are less well understood. The effect on plant design of the evolution of carbon dioxide during leaching is discussed. Evaluation of the equipment and materials of construction would have been almost impossible in a small-scale batch autoclave. It is doubtful whether such results would have generated the necessary confidence to permit decisions to install a commercial-size plant. The development and performance of the multistage pumps, instrumention, shaft seals and shaft-seal water treatment are discussed. It is concluded that the operation of a large-scale continuous pressure-leaching pilot plant to supplement laboratory batch autoclave tests has been a necessary part of the development of this process [af

  9. Pollution reality of gold mining waste on the Witwatersrand

    CSIR Research Space (South Africa)

    Hobbs, PJ

    2010-05-01

    Full Text Available While South Africa has made significant progress in shifting policy frameworks to address mine closure and mine-water management, and the mining industry has changed their practices to conform to new regulations, vulnerabilities in the current...

  10. A case study from the Witwatersrand Gold Basin, South Africa.

    African Journals Online (AJOL)

    group. Tamarugite, apjohnite and jarosite were the predominant sulphate minerals in the salts. .... study area, elevated nitrate levels occurred in residential and wetland areas. ... Ni and As. The most chemically diverse minerals detected were fluellite and ammonium manganese .... Montalbion Silver Mine, north Queensland.

  11. Health Risk Assessment of Heavy Metals in Soils from Witwatersrand Gold Mining Basin, South Africa

    Directory of Open Access Journals (Sweden)

    Caspah Kamunda

    2016-06-01

    Full Text Available The study evaluates the health risk caused by heavy metals to the inhabitants of a gold mining area. In this study, 56 soil samples from five mine tailings and 17 from two mine villages were collected and analyzed for Asernic (As, Lead (Pb, Mercury (Hg, Cadmium (Cd, Chromium (Cr, Cobalt (Co, Nickel (Ni, Copper (Cu and Zinc (Zn using ICP-MS. Measured concentrations of these heavy metals were then used to calculate the health risk for adults and children. Their concentrations were such that Cr > Ni > As > Zn > Cu > Co > Pb > Hg > Cd, with As, Cr and Ni higher than permissible levels. For the adult population, the Hazard Index value for all pathways was found to be 2.13, making non-carcinogenic effects significant to the adult population. For children, the Hazard Index value was 43.80, a value >>1, which poses serious non-carcinogenic effect to children living in the gold mining area. The carcinogenic risk was found to be 1.7 × 10−4 implying that 1 person in every 5882 adults may be affected. In addition, for children, in every 2725 individuals, 1 child may be affected (3.67 × 10−4. These carcinogenic risk values were both higher than acceptable values.

  12. Tectonosedimentary model for the central Rand Goldfield, Witwatersrand basin, South Africa

    CSIR Research Space (South Africa)

    Stewart, RA

    2004-12-01

    Full Text Available is oligomictic consisting of approximately 90"/;! white and S'Mi smoky vein quartz cla.sts and 5">ii blue opale.scent quartz clasts- Locaiisetl (typically ranges of less than 10m) dark-grey, fine-grained quaitzite matrix occurs. On average, the Main Reef Leader....ssociitted with higher goki grades relaiive to the lower conglomerate and the Main Reef (I). Rolfe. personal communication, 2(KH)). The high proportion {1S%) of blue opale.scent t|uarlz cla.sts in the hangingwall conglomerate band is t haractcristic of the South Reef...

  13. Radiometric determination in situ of the face grades in Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Smit, C.J.B.

    1985-01-01

    A prototype collimated radiometric face scanner was tested in the Harmony Gold Mine. The results obtained during the pilot study indicate that in situ radiometric uranium assays are statistically indistinguishable from those obtained conventionally from channel chip samples. In addition, the study demonstrated that reasonably reliable gold estimates can be deduced from the radiometric measurements, by use of the ratio of gold to uranium within a mine. The instrumentation, calibration procedures, and background determination are described briefly

  14. Primary dispersal patterns of uraninite in the Proterozoic Vaal Reef placer deposit, Witwatersrand, South Africa

    International Nuclear Information System (INIS)

    Minter, W.E.L.

    1981-01-01

    The Vaal Reef is a strata-bound uranium orebody. Uraninite, together with nodular pyrite and gold, is a detrital heavy-mineral component of the sediment. Consequently, the areal distribution patterns of uranium content match the braided, southeasterly dispersal pattern evident in the Vaal Reef. Deeper channelways contain more uraninite

  15. Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand

    Directory of Open Access Journals (Sweden)

    Marc S. Humphries

    2017-01-01

    Full Text Available Wetlands are well known to be efficient at sequestering pollutants from contaminated water. We investigated metal accumulation in the peats of the Klip River, a natural wetland that has received contaminated water from gold mining operations in Johannesburg for over 130 years. Previous work conducted in the downstream portion identified the wetland as an important system for sequestering metals. We focused on the upstream section of the wetland, more proximal to the source of acid mine drainage, to provide a better understanding of the pollutant sources and the role of the wetland in pollutant attenuation. Geochemical and mineralogical analyses of peat cores revealed considerable metal enrichments in the peat ash, particularly in Co, Ni, Zn, Pb, Cu and U. Metal concentrations are typically between 4 to 8 times higher than those previously reported for the downstream, more distal portion of the wetland. The distribution of metal accumulation within the peat profiles suggests that contamination arises from a combination of sources and processes. Elevated concentrations in the shallow peat are attributed to the input of contaminated surface water via tributaries that drain the Central Rand Goldfield, whereas enrichments in the deeper peat suggest significant sub-surface inflow of contaminated water through the underlying dolomitic rocks. Metal immobilisation occurs through a combination of mechanisms, which include the precipitation of gypsum, metal sulfides, Fe-Mn oxyhydroxides and phosphates. Our study highlights the environmental and economic importance of natural wetland systems which have the ability to accumulate large quantities of metals and thus remediate polluted waters.

  16. Delineation of rockburst fractures with ground penetrating radar in the Witwatersrand Basin, South Africa

    CSIR Research Space (South Africa)

    Grodner, M

    2001-09-01

    Full Text Available high potential for rockbursts exists. Rockbursts cause injuries and deaths to the workers and lost production time. One of the techniques for reducing the severity of damage of face-bursts (a class of rockbursts where the mining face is ejected...

  17. Geotechnical classification of deep and ultra-deep Witwatersrand mining areas, South Africa

    CSIR Research Space (South Africa)

    Schweitzer, JK

    1997-06-01

    Full Text Available ?cantly with depth (e.g. Gurtunca and Gay 1993a, b; Roberts et al. 1994), numerous researchers stress the importance of, and requirement for, geotechnical information, es- pecially geological features at great depths (e.g. Adams et al. 1981; Gay et al. 1984; Gay 1986...; Gay and Jager 1986a, b; Roberts and Jager 1991, 1993; Kullman et al. 1994; Gay et al. 1995a, b). The geotechnical information must also be considered when proposing modi?cations to current mining methods (Johnson and Schweitzer 1996). Mineralium...

  18. Department of Surgery, University of the Witwatersrand – a brief history

    African Journals Online (AJOL)

    result the departure of professors of anatomy and physiol- ogy was not permitted. .... details of the dog on which this surgery had been performed) and Underwood ... (Sholem Kay), breast cancer surgery (Myron Lange), thyroid diseases (Theo ...

  19. The information needs of cancer patients in the Pretoria and Witwatersrand area

    Directory of Open Access Journals (Sweden)

    H. A. McLoughlin

    1996-03-01

    Full Text Available More than 48 500 South Africans annually are confronted with the diagnosis of cancer. (Sitas, 1994 Judging from the literature it would seem that the acquisition of information about the various aspects of their disease is a very important coping mechanism for the cancer patient. Various studies concerning the information needs of cancer patients have been published in the USA, the UK and Australia, Similar studies have not yet been published in South Africa.

  20. Report on the feasibility of the in situ radiometric determination of uranium grade in Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Smit, C.J.B.; Wesolinski, E.S.; Corner, B.

    1982-08-01

    The chip-sampling technique currently employed by the South African gold and uranium-mining industry, for the prediction of face grade, has several drawbacks, namely: 1) it is labour-intensive; 2) sample volumes are often unrepresentative and prone to human error; and 3) the uranium mineralisation may be very erratic along the reef. In situ radiometric assaying for uranium along the reef, on the other hand, is a rapid, essentially one-man operation, enabling a much larger and hence a more representative sample volume to be measured. The high radiometric background inherent in any uranium mine necessitates some form of high-density shielding in order to facilitate quantitative in situ assaying. This report, therefore, briefly outlines the origin, nature, detection and shielding of gamma rays. Results obtained with a frontally shielded total-count instrument showed that radiometric estimates of uranium grade are comparable to those obtained by batch mining and can be used for the prediction of face grades, provided that the ore is in radiometric equilibrium and that thorium and potassium are either not present, or vary sympathetically with the uranium grade. Spectral analysis showed, however, that these circumstances will also permit the use of a collimated (side-shielded) detector of acceptable weight, provided that only the low-energy portion of the spectrum is measured. The advantages of a collimated detector over a frontally shielded detector are also noteworthy, viz.: 1) only one reading is taken per sample point rather than two, as is the case with the frontally shielded system, thus improving counting statistics; and 2) the shielding is permanently fixed to the detector. Comprehensive design considerations for a compact, portable instrument are suggested and methods for determining background radiation as applicable to a collimated detector are described

  1. University of the Witwatersrand physiotherapy undergraduate curriculum alignment to medical conditions of patients within Gauteng state health facilities

    Directory of Open Access Journals (Sweden)

    Mokgobadibe V. Ntsiea

    2017-06-01

    Conclusion: The Wits physiotherapy curriculum covers all medical conditions treated by physiotherapists within the Gauteng state health facilities, and overall, the curriculum prepares the students to practise in a variety of situations.

  2. Examples that illustrate sedimentological aspects of the proterozoic placer model on the Kaap-Vaal Craton, Witwatersrand, South Africa

    International Nuclear Information System (INIS)

    Minter, W.E.L.

    1981-01-01

    In the fluvial-fan model of Proterozoic placers in South Africa, mid-fan and fanbase environments are illustrated by the Ventersdorp Contact Reef, proximal braided-belt environments by the B Reef, distal braided-belt environments by the Vaal Reef, and deltaiclike environments by sheets, ribbons, and pods at the extremities of the South and Basal Reefs. The nature of distribution of gold and uranium in these various environments has been evaluated and the knowledge successfully applied by the author to the valuation and practical mining of the reefs since 1965

  3. Molecular and elemental analyses of the carbonaceous matter in the gold and uranium bearing Vaal Reef carbon seams, Witwatersrand sequence

    International Nuclear Information System (INIS)

    Zumberge, J.E.; Sigleo, A.C.; Nagy, B.

    1978-01-01

    The thin Vaal Reef carbon seams consist of a complex, solid, and solvent insoluble, polymer-like substance, containing mainly hydrocarbons and some organic sulphur and oxygen compounds. These carbon seams are not pure carbon, e.g. graphite, and do not contain only hydrocarbons. According to modern terminology the Vaal Reef carbonaceous matter is most appropriately referred to as kerogen rather than carbon or thucholite. This kerogen is not the result of the polymerization of gaseous or liquid hydrocarbons, but rather of the polymerization of biochemicals from decayed, primitive Precambrian micro-organisms. These microbiota formed mats in which uranium minerals and gold became incorporated before burial under younger sediments. Organic geochemistry was first developed as a means to elucidate the nature and composition of petroleum and coal. Later it was successfully used in lunar sample, planetary surface, and meteorite studies as well as in investigations of kerogens in terrestrial sediments of various ages. Considering economic geology, organic geochemistry holds promise for elucidating the origin and helping in the exploration of carbonaceous ore deposits. The purpose of this report is to review some of the major current organic geochemical methods and to illustrate these by the analysis of the Vaal Reef kerogen. The samples were analysed by a directly connected high vacuum pyrolysis system-gas chromatograph-organic mass spectrometer. Additional analyses were performed by a combined scanning electron microscope-electron microprobe, by the techniques of electron paramagnetic resonance spectroscopy, and by neutron activation analysis

  4. Effect of the rock properties on mining-induced seismicity around the Ventersdorp contact reef, Witwatersrand basin, South Africa

    CSIR Research Space (South Africa)

    Milev, AM

    2002-01-01

    Full Text Available stream_source_info milev_2002.pdf.txt stream_content_type text/plain stream_size 83892 Content-Encoding ISO-8859-1 stream_name milev_2002.pdf.txt Content-Type text/plain; charset=ISO-8859-1 C69C128C101C99C116 C111C102 C...116C104C101 C82C111C99C107 C80C114C111C112C101C114C116C105C101C115 C111C110 C77C105C110C105C110C103C45C105C110C100C117C99C101C100 C83C101C105C115C109C105C99C105C116C121 C65C114C111C117C110C100 C116C104C101 C86C101C110C116C101C114C115C100C111C114C112 C...

  5. 3D edge detection seismic attributes used to map potential conduits for water and methane in deep gold mines in the Witwatersrand basin, South Africa

    CSIR Research Space (South Africa)

    Manzi, MSD

    2012-09-01

    Full Text Available Inrushes of ground water and the ignition of flammable gases pose risks to workers in deep South African gold mines. Large volumes of water may be stored in solution cavities in dolomitic rocks that overlie the Black Reef (BLR) Formation, while...

  6. The nature of a deformation zone and fault rock related to a recent rockburst at Western Deep Levels Gold Mine, Witwatersrand Basin, South Africa

    Science.gov (United States)

    Stewart, R. A.; Reimold, W. U.; Charlesworth, E. G.; Ortlepp, W. D.

    2001-07-01

    In August 1998, a major deformation zone was exposed over several metres during mining operations on 87 Level (2463 m below surface) at Western Deep Levels Gold Mine, southwest of Johannesburg, providing a unique opportunity to study the products of a recent rockburst. This zone consists of three shear zones, with dip-slip displacements of up to 15 cm, that are oriented near-parallel to the advancing stope face. Jogs and a highly pulverised, cataclastic 'rock-flour' are developed on the displacement surfaces, and several sets of secondary extensional fractures occur on either side of the shear zones. A set of pinnate (feather) joints intersects the fault surfaces perpendicular to the slip vector. Microscopically, the shear zones consist of two pinnate joint sets that exhibit cataclastic joint fillings; quartz grains display intense intragranular fracturing. Secondary, intergranular extension fractures are associated with the pinnate joints. Extensional deformation is also the cause of the breccia fill of the pinnate joints. The initial deformation experienced by this zone is brittle and tensile, and is related to stresses induced by mining. This deformation has been masked by later changes in the stress field, which resulted in shearing. This deformation zone does not appear to be controlled by pre-existing geological features and, thus, represents a 'burst fracture', which is believed to be related to a seismic event of magnitude ML=2.1 recorded in July 1998, the epicentre of which was located to within 50 m of the study locality.

  7. Some aspects of the development of the Vaal Reef uranium-gold carbon seams, Witwatersrand sequence: organic geochemical and microbiological considerations

    International Nuclear Information System (INIS)

    Zumberge, J.E.; Nagy, B.; Nagy, L.A.

    1981-01-01

    The solvent-insoluble organic matter (kerogen) that is the predominant syngenetic component of the Vaal Reef carbon seams was analyzed by combined high-vacuum pyrolysis gas-chromatography mass spectrometry, combined electron microprobe-scanning electron microscopy and electron paramagnetic resonance spectroscopy. The pyrolysis results indicate that the Vaal Reef carbon is a random polymer-type matter consisting mainly of aromatic and short-chain aliphatic hydrocarbons, as well as aromatic and other organic-sulfur constituents. Scanning electron microscopy revealed coccoid and filamentous microstructures in the carbonaceous seams. These structures are conceivably of biological affinity and may be fossil blue-green algae and (or) bacteria. Gold is often concentrated at the interfaces of admixed clay-carbon microenvironments. This implies physical and chemical interactions between clays and organic matter conducive to the entrapment of detrital gold during deposition and the crystallization of colloidal/dissolved gold in the carbon seams. High concentrations of organic free radicals (molecules with unpaired electrons) in the carbonaceous matter, deduced from electron paramagnetic resonance spectroscopy, suggest that radiation emitted from uranium played a unique role in the reconstitution and polymerization of the progenitor biochemicals

  8. Research collaboration 2011: a joint publication highlighting the research partnerships between Tshwane University of Technology, University of Johannesburg, University of the Witwatersrand and the CSIR

    CSIR Research Space (South Africa)

    CSIR

    2011-01-01

    Full Text Available to be productive during 2011. The three Universities collaborated with the CSIR through research projects, teaching and supervision of the student research, exchange of staff and the use of facilities. Collaborative projects and supervised student research have...

  9. Ventilatory Function in Relation to Mining Experience and Smoking in a Random Sample of Miners and Non-miners in a Witwatersrand Town1

    Science.gov (United States)

    Sluis-Cremer, G. K.; Walters, L. G.; Sichel, H. S.

    1967-01-01

    The ventilatory capacity of a random sample of men over the age of 35 years in the town of Carletonville was estimated by the forced expiratory volume and the peak expiratory flow rate. Five hundred and sixty-two persons were working or had worked in gold-mines and 265 had never worked in gold-mines. No difference in ventilatory function was found between the miners and non-miners other than that due to the excess of chronic bronchitis in miners. PMID:6017134

  10. Proceedings of the international conference on dynamical properties of heavy-ion reactions held at the University of the Witwatersrand, v. 1

    International Nuclear Information System (INIS)

    Engelbrecht, C.A.; Lemmer, R.H.; Sellschop, J.P.F.; Toeppfer, C.

    1978-01-01

    The report contains abstracts of the papers delivered at the conference. The abstracts have been grouped into the following chapters: Very heavy nuclei; Deep inelastic reactions and fusion; Resonances; Elastic and quasi-elastic scattering; Atomic physics with heavy ions; Miscellaneous; Post-deadline contributions. Each abstract has been submitted to INIS separately

  11. Integrated interpretation of 3D seismic data to enhance the detection of the gold-bearing reef: Mponeng Gold mine, Witwatersrand Basin (South Africa)

    CSIR Research Space (South Africa)

    Manzi, M

    2015-07-01

    Full Text Available The authors present an integrated approach to the seismic interpretation of one of the world's deepest gold ore body (Carbon Leader Reef) using three-dimensional seismic data, ultrasonic velocity measurements at elevated stresses, and modified...

  12. The development and application of quantitative methods for the determination of in-situ radiometric uranium grade on the Witwatersrand gold and uranium mines

    International Nuclear Information System (INIS)

    Symons, G.

    1985-12-01

    A detailed investigation of background radiation levels near the reef zone in the uranium section of the Western Areas Mine was conducted using a collimated radiometric face scanner. This study demonstrated that these radiation levels can be high; 25% or more of the counts measured when sampling a reef face may originate from a background source, especially from uranium ore rubble on the footwall close to the reef face. A method using a 20mm frontal shield was devised to obtain an accurate background correction. Three calibration schemes, the Area method, the Gamlog method, and the Deconvolution method were implemented for the production of accurate in-situ radiometric uranium grades. This involved the construction of a step-response calibration pad at Pelindaba together with the establisment of appropriate software and underground radiometric sampling procedures. Radiometric grades generated by these calibration procedures from 60 channel sections were on average 10% below those procured from conventional chip sampling. A correlation between gold and uranium grades was also evident. Crushed rock samples were collected to investigate the thorium problem and are still undergoing analysis at the time of writing. Refinements in the design of the collimated face scanner are also described

  13. Neoarchaean tectonic history of the Witwatersrand Basin and Ventersdorp Supergroup: New constraints from high-resolution 3D seismic reflection data

    CSIR Research Space (South Africa)

    Manzi, MSD

    2013-04-01

    Full Text Available Rand Group (ca. 2985–2902 Ma) is unconformably overlain by the Central Rand Group (ca. 2902–2849 Ma), with tilting of the West Rand Group syn- to post-erosion at ca. 2.9 Ga. The seismic sections also confirm that an unconformable relationship exists...

  14. Occurrence, emission and ignition of combustible strata gases in Witwatersrand gold mines and Bushveld platinum mines, and means of ameliorating related ignition and explosion hazards, Part 1: literature and technical review.

    CSIR Research Space (South Africa)

    Cook, AP

    1998-10-01

    Full Text Available 60 62 63 64 9 Terminology and abbreviations The terms combustible, flammable and inflammable, to describe gases encountered in mining, are all used commonly in literature and within the South African mining industry. The Concise Oxford English... dictionary defines them as: combustible: capable of burning inflammable: easily set on fire flammable: rarely used except in “nonflammable”. In this report combustible and flammable are used to describe gas or gases that will burn or explode in air...

  15. A review of reflection seismic investigations in three major metallogenic regions: The Kevitsa Ni–Cu–PGE district (Finland), Witwatersrand goldfields (South Africa), and the Bathurst Mining Camp (Canada)

    CSIR Research Space (South Africa)

    Malehmir, A

    2014-01-01

    Full Text Available -resolution image of the subsurface and information about structural and lithological relationships that control mineral deposits. The method has also become an attractive geophysical tool for deep exploration and mine planning. In this paper, we review the use...

  16. Proceedings of the international conference on dynamical properties of heavy-ion reactions held at the University of the Witwatersrand, Johannesburg, South Africa, 1-3 August 1978. v. 3

    International Nuclear Information System (INIS)

    Sellschop, J.P.F.; Lemmer, R.H.; Toepffer, C.; Engelbrecht, C.A.

    1978-01-01

    At this pre-conference symposium lectures on 'applications of (heavy) ions' were delivered. The following topics were discussed: 1) heavy ions in archaeological dating, 2) nuclear physics in metallurgy, 3) nuclear physics in solid-state research, 4) nuclear probes in geological studies, and 5) nuclear approaches in biological investigations

  17. Proceedings of the international conference on dynamical properties of heavy-ion reactions held at the University of the Witwatersrand, Johannesburg, South Africa, August 1-3, 1978. v. 4

    International Nuclear Information System (INIS)

    Sellschop, J.P.F.; Toepffer, C.; Lemmer, R.H.; Engelbrecht, C.A.

    1978-01-01

    At this post-conference school invited lectures on 'Topical themes in heavy-ion scattering' were delivered. The following topics were discussed; 1) the measurement of magnetic moments of nuclear states of high angular momentum; 2) nuclei at very high angular momentum; 3) multi-step direct reaction analysis of deep inelastic spectra in nuclear reactions: 4) experiments relating to quantum electrodynamics of strong field and 5) the role of deep inelastic processes in nuclear physics

  18. Preliminary notes concerning the uranium-gold ratio and the gradient of heavy-mineral size distribution as factors of transport distance down the paleoslope of the Proterozoic Steyn Reef placer deposit, Orange Free State Goldfield, Witwatersrand, South Africa

    International Nuclear Information System (INIS)

    Minter, W.E.L.

    1981-01-01

    The size decrease of quartz pebbles, pyrite nodules, and zircon grains, evident from samples of Steyn Reef taken from various positions down a paleoslope indicated by crossbedding data, confirms their detrital origin. An increase in the ratio of uranium to gold, which appears to be related to their original size-frequency distribution, also indicates the paleoslope direction and effectively distinguishes between blanket and carbon-seam reefs

  19. Tail swing performance of the South African car-carrier fleet

    CSIR Research Space (South Africa)

    De Saxe, C

    2012-09-01

    Full Text Available PERFORMANCE OF THE SOUTH AFRICAN CAR-CARRIER FLEET Obtained BSc and currently completing MSc at the University of the Witwatersrand. Researcher at the Council for Scientific and Industrial Research (CSIR) through the CSIR?s Studentship programme.... Obtained BSc and MSc from the University of the Witwatersrand and PhD from the University of Cambridge. Senior Lecturer in the School of Mechanical, Industrial and Aeronautical Engineering at the University of the Witwatersrand. C. DE SAXE...

  20. South African Journal of Bioethics and Law: Contact

    African Journals Online (AJOL)

    Principal Contact. Ames Dhai Editor University of Witwatersrand University of Witwatersrand Private Bag X1 Pinelands 7430 Cape Town South Africa Phone: 011 717 2718. Email: Amaboo.Dhai@wits.ac.za. Support Contact. Emma Buchanan Phone: 021 657 8200. Email: emmab@hmpg.co.za. ISSN: 1999-7639.

  1. side-effects of oral misoprostol in the third stage of labour

    African Journals Online (AJOL)

    Research on Human Subjects of the University of the. Witwatersrand. Women in .... levels of stress hormones can have permanent adverse effects on the baby's brain, resulting in behaviour disorders and lower IQ later in life. Mother's love.

  2. The Vaal river catchment: Problems and research needs

    CSIR Research Space (South Africa)

    Braune, E

    1987-01-01

    Full Text Available The vaal river catchments contains South African's economic heartland, the Pretoria -Witwatersrand-Vereeniging (PWV) complex. Although the catchments only produces eight per cent of the mean annual runoff of the country it has highest concentration...

  3. Over-reported peripheral neuropathy symptoms in a cohort of HIV ...

    African Journals Online (AJOL)

    2014-06-02

    WRHI), Associate Professor,. 10. Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa, email: fventer@wrhi. ac.za. Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, ...

  4. Serum procalcitonin as an early marker of neonatal sepsis

    African Journals Online (AJOL)

    , MD, DTM&H, FCPath (SA). Department of Statistics and Actuarial Science, University of the Witwatersrand,. Johannesburg. Jacky Galpin, PhD, BSc. October 2004, Vol. 94, No. 10 SAMJ possible infection and 13 definite infection. PCT differed.

  5. Transient heat transfer in longitudinal fins of various profiles with ...

    Indian Academy of Sciences (India)

    School of Computational and Applied Mathematics, University of the Witwatersrand, ... by frequent encounters of fin problems in many engineering applications to enhance heat transfer. In recent .... where β is the thermal conductivity gradient.

  6. METHYLPHENIDATE (RITALIN) USE AND ABUSE

    African Journals Online (AJOL)

    University ofthe Witwatersrand Medical School and Johannesburg Hospital. James A TemIett, MB BCh, .... other substances such as heroin, cocaine, LSD or cannabis. Intravenous substance ... intractable cancer pain. Attempts to get addicted ...

  7. The Effect of Solvent on the Ligand Substitution Reactions of ...

    African Journals Online (AJOL)

    NJD

    Vitamin B. 12a. ) Leanne Knapton and Helder M. Marques*. Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050 South Africa. Received 28 June 2005; revised 2 February 2006; ...

  8. Mapping seismic vulnerability in stopes in deep South African gold mines

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-09-01

    Full Text Available -JICA Science and Technology Research Partnership for Sustainable Development (SATREPS), 2Council for Scientific and Industrial Research, South Africa, 3University of the Witwatersrand, Republic of South Africa, 4Ritsumeikan University, Japan, 5Seismogen cc...

  9. Associations of objectively and subjectively measured physical ...

    African Journals Online (AJOL)

    Exercise Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South ... and appendicular bones have denser and stronger ..... of weight-bearing activity without any changes in CoD.

  10. Climbing ripple structure and associated storm-lamination from a ...

    Indian Academy of Sciences (India)

    Pranhita–Godavari Valley, south India, displays well developed climbing ripple lamination and ... sedimentary environments, such as river flood .... Sediment, sequence and facies ..... tic Archaean Witwatersrand Supergroup, South Africa;.

  11. AREF_2nd proofs.indd

    African Journals Online (AJOL)

    Kirstam

    2014-07-02

    Jul 2, 2014 ... a*School of Statistics and Actuarial Science, University of the Witwatersrand, .... Figure 4: Plot of residuals, probability density and the Q-Q plot ..... 'Statistical inference using extreme order statistics', Annals of Statistics, vol.

  12. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    MFOS). Medical Research Council/University of the Witwatersrand Dental Research. Institute ..... Civil disturbance and anaesthetic workload in the ... Alper M, TotalS, Cankayali R, Songur E. Gunshot wounds of the face in attempted suicide.

  13. Recognition and diagnosis of chronic obstructive pulmonary disease

    African Journals Online (AJOL)

    the USA and Europe only 23% of individuals presenting with COPD were accurately ... Senior Consultant, Chris Hani Baragwanath Hospital, University of the Witwatersrand, Johannesburg. Andrew ... recession of the lower ribs on inspiration.

  14. Proceedings of plumes, plates and mineralisation symposium: an introduction

    CSIR Research Space (South Africa)

    Hatton, CJ

    1997-12-01

    Full Text Available of plume-theory. Mechanisms of magma formation are identified and plume positions and distances to their surface expression considered. Mantle plumes are considered as a heat and fluid source for the Witwatersrand gold deposits....

  15. Gluteus medius kinesio-taping: the effect on torso-pelvic separation ...

    African Journals Online (AJOL)

    1 Physiotherapy Department, Faculty of Health Sciences, University of the. Witwatersrand ... accomplish this, the club head should be travelling at maximum speed at the .... analysed using a paired Student's t-test, when testing at the 0.05 level.

  16. A review of antenatal corticosteroid use in premature neonates in a ...

    African Journals Online (AJOL)

    distress syndrome (RDS) in preterm neonates. ... The use of ANSs in low- and middle-income countries (LMICs) ... 1 Department of Paediatrics and Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, ...

  17. A note on the interplay between symmetries, reduction and ...

    Indian Academy of Sciences (India)

    3School of Mathematics and Centre for Differential Equations, Continuum Mechanics and. Applications, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050,. South Africa ..... Malaysia for the facilities and financial support.

  18. Promoting Early Detection of Breast Cancer and Care Strategies for ...

    African Journals Online (AJOL)

    USER

    Canada1; University of Witwatersrand, South Africa2; Department Nursing ... decisions and choices about the most appropriate health care for their ... likely help to improve care processes, the quality of clinical decisions and patient treatment.

  19. Recommendations for the acute and long-term medical ...

    African Journals Online (AJOL)

    2012-12-21

    Dec 21, 2012 ... decline in physical activity and increasing frailty, have ... Drug therapy and hospital admissions further added ... Honorary Lecturer, Division of Geriatric Medicine, Department of Medicine, University of the Witwatersrand.

  20. managing hiv as a chronic disease: using interactive data collection ...

    African Journals Online (AJOL)

    Enrique

    2004-11-02

    Nov 2, 2004 ... Clinical Director, Reproductive Health Research Unit, University of the Witwatersrand, Johannesburg ... In the Chronic Care Model described by Ed Wagner,11 this interaction can be ... pharmacists re-enter demographic.

  1. African Journal of Drug & Alcohol Studies, 12(1), 2013 Copyright ...

    African Journals Online (AJOL)

    5Witwatersrand Reproductive Health & HIV Institute (WRHI), Faculty of Health. Sciences ... were more likely to engage in risky sex practices ..... and stress management, whilst Doumas. & Hannah ...... success or failure of a study. In addition.

  2. The Operations Research Society of South Africa

    CSIR Research Space (South Africa)

    Ittmann, HW

    2010-06-01

    Full Text Available ), the Univer- sity of the Witwatersrand (WITS), the North- West University, and also the University of Pretoria. One or two of the ??previously disad- vantaged institutions??, or Historically Black Universities, have relative large OR depart- ments...

  3. Adolescent experiences of HIV and sexual health communication ...

    African Journals Online (AJOL)

    Christine N. Soon

    2014-05-09

    May 9, 2014 ... MA, is a Social Scientist at the Perinatal HIV Research Unit, University of the. Witwatersrand .... study staff and through word-of-mouth, as they were readily ..... social media sources and innovative HIV prevention campaigns in.

  4. Sap flow in Searsia pendulina and Searsia lancea trees established on gold mining sites in central South Africa

    CSIR Research Space (South Africa)

    Dye, P

    2017-03-01

    Full Text Available The Witwatersrand Basin Goldfields (WBG) have seen over a century of continuous mining that has generated extensive tailings storage facilities (TSF), together with “footprints” remaining after the residue has been removed for reprocessing...

  5. Room temperature nanoindentation creep of hot-pressed B6O

    CSIR Research Space (South Africa)

    Machaka, R

    2014-06-01

    Full Text Available of the nanoindentation creep behavior in B6O ceramics. 1 Room temperature nanoindentation creep of hot-pressed B6O Ronald Machakaa,b,* , Trevor E. Derryb,d, Iakovos Sigalasb,c aLight Metals, Materials Science and Manufacturing, Council for Scientific..., University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa dSchool of Physics, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, 2050 South Africa Abstract: Nanoindentation has become a widely...

  6. Progress report to the Nuclear Analysis Subcomittee for Nuclear Technology and Radiation for the period 1 January 1977 to 31 December 1977

    International Nuclear Information System (INIS)

    This report covers the activities of the Activation Analysis Research Group (AARG) in the Nuclear Physics Research Unit of the University of the Witwatersrand. This Group has components from the Atomic Energy Board, the National Institute of Metallurgy, and receives support also from the Chamber of Mines Research Organization, the National Cancer Association, Diamond Research Laboratory and the University of the Witwatersrand. In this report the major emphasis is given to those projects carried out by the Atomic Energy Board-seconded scientific staff, but all other projects are listed with a brief note on progress, for completeness and in the interest of obviating unnecessary duplication

  7. Paleosol at the Archean–Proterozoic contact in NW India revisited ...

    Indian Academy of Sciences (India)

    1. Department of Geology, University of Rajasthan, Jaipur 302 004, India. 2. Institut für .... region around Udaipur (NW India) large occur- rences of .... top of the section reddish colors (iron-oxide leach- ..... for Witwatersrand gold; Soc. Econ.

  8. Current indications for open Kuntscher nailing of femoral shaft ...

    African Journals Online (AJOL)

    Current indications for open Kuntscher nailing of femoral shaft fractures. A S Bajwa FCS(SA)ORTH. E Schnaid FCS(SA)ORTH. M E B Sweet MD PhD(rned). University of Witwatersrand, Johannesburg, South Africa. Key Words: Kuntscher nail, intramedullary nail, femoral fracture. We retrospectively reviewed 32 patients with.

  9. Distribution of Resources for Paediatric Cardiac Surgery

    African Journals Online (AJOL)

    QuickSilver

    2003-05-07

    May 7, 2003 ... Witwatersrand. 4. World Health Report (1997). Fighting disease, fostering development. World Health Forum, 18, 1-8. 5. Dulskiene V. Prevalence of Congenital Heart Defects in Newborns and Infants. Medicina 2002; 38(3):348-3. Introduction. South Africa is a developing country with a per capita expendi-.

  10. South African clinical practice guidelines: A landscape analysis

    African Journals Online (AJOL)

    2018-01-24

    Jan 24, 2018 ... 1 PRICELESS SA, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. 2 Cochrane South Africa, South African Medical Research ..... collaboratively, developing and maintaining smartphone applications that provide access to the most up-to-date ...

  11. The relevance of surveying content in mining engineering education ...

    African Journals Online (AJOL)

    The University of the Witwatersrand School of Mining Engineering (Wits Mining) has its origins in the South African School of Mines, which was established in 1896. It is currently recognised as one of the world's top mining engineering schools that educate mining engineering candidates to become qualified to specialise in ...

  12. LA TITUDE-LONGITUDE GRID MAPS OF AFRICA (CCTA ...

    African Journals Online (AJOL)

    of mapping see de Meillon, B., Davis, D. H. S., and Hardy, F., Plague in Southern Mrica. I. The Siphonaptera. Government Printer, Pretoria, 1961, or consult CCTAjCSA Publication. No. 29, referred to above. * Climatological Atlas of Africa, compiled and edited in the African Climatology Unit, University of the. Witwatersrand ...

  13. Observational studies of the rock mass response to mining in highly-stressed gold mines in South Africa

    CSIR Research Space (South Africa)

    Ogasawara, H

    2014-09-01

    Full Text Available , Japan M Nakatani The University of Tokyo, Japan RJ Durrheim CSIR & the University of the Witwatersrand, South Africa M Naoi Kyoto University, Japan Y Yabe, H Moriya Tohoku University, Japan GF Hofmann, C Stander, DP Roberts, P de Bruin, J...

  14. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Effects of non-uniform interfacial tension in small Reynolds number flow past a spherical liquid drop ... Centre for Differential Equations, Continuum Mechanics and Applications, School of Computational and Applied Mathematics, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa ...

  15. CASE REPORT Echinococcal disease of the bone: An unusual ...

    African Journals Online (AJOL)

    Fig.1. Plain radiographs demonstrate a multilocular lucent lesion in the mid- shaft of the right radius, complicated by pathological fracture. Fig. 2. Histological slide indicating the presence of a hydatid hooklet (arrow). (Figure by courtesy of the Division of Anatomical Pathology/NHLS, University of the Witwatersrand).

  16. Squamous Carcinoma of the Paranasal Sinuses in the Bantu*

    African Journals Online (AJOL)

    in terms of both the patient's suffering and the poor results of treatment. ... carcinoma of the larynx and lungs, however, over 80% of the cases .... tive means of improving cure rates. ... Palliative radiotherapy. 12. 8. 3. 8. Radical radiotherapy*. 15. 6. 51. 21. 11. 20 ... of the Witwatersrand Medical School. ... J. Cancer, 9, 528. 3.

  17. medico-legal an overview of some of the key legal developments in ...

    African Journals Online (AJOL)

    Enrique

    equipped to admit a child with HIV as none of its teachers ... Head, Legal Unit, AIDS Law Project, and Centre for Applied Legal Studies, University of the Witwatersrand, Johannesburg ... once they have certified that the test or treatment is in the.

  18. Providing Opportunities for Student Self-Assessment: The Impact on the Acquisition of Psychomotor Skills in Occupational Therapy Students

    Science.gov (United States)

    Jay, Julie; Owen, Antonette

    2016-01-01

    The Occupational Therapy department at the University of the Witwatersrand in South Africa is responsible for ensuring students achieve psychomotor skill proficiency, as it is an essential component of health care practice. The aim of this study was to determine whether the introduction of opportunities to afford self-evaluation better prepared…

  19. Prevalence of and contributing factors to dyslipidaemia in low ...

    African Journals Online (AJOL)

    2012-03-28

    Mar 28, 2012 ... was approved by the University of the Witwatersrand Medical Ethics ..... Community nutrition textbook for South Africa: a rights-based approach. ... London: Springer Science and Business Media, LLC; in press. 35. ... Case A, Menendez A. Sex differences in obesity rates in poor countries: evidence from.

  20. Confidentiality concerning HIV/AIDS status - the implications of the ...

    African Journals Online (AJOL)

    His evidence justifying his disclosure was that he was. Department of Orthodontics, University of the Witwatersrand,. Johannesburg. J. T. Dancaster. BD.S. Department of Business Administration, University of Natal, Durban ... Supreme Court judgement, the Appeal judgement notes that not only did Kruger not seek to obtain ...

  1. Kanna hy kô hystoe, Joanie Galant-hulle en

    African Journals Online (AJOL)

    Owner

    Vermeulen (3) beskryf dié agtergrond soos volg: “Kanna hy kô hystoe(1965) wortel, soos. Adam Small se ... ten opsigte van die titelkarakters in Van Wyk Louw se dramas Dias(1952) en Germanicus ...... tesis, U van Witwatersrand, 1984. Olivier ...

  2. Comparison of an enzyme-immunoassay with a radio-immunoassay ...

    African Journals Online (AJOL)

    1990-07-21

    Jul 21, 1990 ... patient's serum is added to beads coated with HBsAg and, after a period of incubation, HBsAg conjugated with iodine-. 125 which binds to any anti-HBs on the bead, is added. Department of Virology, University of the Witwatersrand and National Institute for Virology, Johannesburg. N. K. BLACKBURN, F.LM ...

  3. ORIGINAL ARTICLES Nurses at risk for occupationally acquired ...

    African Journals Online (AJOL)

    black, Asian, and Caucasian blood donors, respectively.2,3 The HBV carrier rate (as ... only 30.6% of the nurses were immune to infection with the virus, ..... of Witwatersrand, Johannesburg; research grants for registrars in the clinical ...

  4. Guided elastic waves produced by a periodically joined interface in a rock mass

    CSIR Research Space (South Africa)

    Yenwong Fai

    2012-09-01

    Full Text Available on Computational and Applied Mechanics SACAM2012 Johannesburg, South Africa, 3−5 September 2012 c©SACAM Guided Elastic Waves Produced by a Periodically Joined Interface in a Rock Mass A.S. Yenwong Fai School of Physics University of the Witwatersrand Johannesburg...

  5. Teaching Process Design through Integrated Process Synthesis

    Science.gov (United States)

    Metzger, Matthew J.; Glasser, Benjamin J.; Patel, Bilal; Hildebrandt, Diane; Glasser, David

    2012-01-01

    The design course is an integral part of chemical engineering education. A novel approach to the design course was recently introduced at the University of the Witwatersrand, Johannesburg, South Africa. The course aimed to introduce students to systematic tools and techniques for setting and evaluating performance targets for processes, as well as…

  6. An investigation into the availability and role of oxygen gas in gold ...

    African Journals Online (AJOL)

    The oxygen content of tailings dams around the Witwatersrand Basin was quantitatively measured over a period of 2 months using a multi-level gas sampling device (MLGS) in an attempt to understand the diffusion of oxygen in tailings dams as a result of acid mine drainage. The measured oxygen showed that the diffusion ...

  7. How wide is the gap between high school and first-year chemistry at ...

    African Journals Online (AJOL)

    The aim of the study was to identify the nature and extent of the gap between high school and first-year chemistry at the University of the Witwatersrand. The investigation was done at the macro and micro levels. At the macro level high school physical science and first-year chemistry syllabuses were compared. The testing ...

  8. Uraniferous quartz-pebble conglomerates in South Africa

    International Nuclear Information System (INIS)

    von Backstroem, J.W.

    1981-01-01

    The purpose of this paper is to give a short background statement summarizing data on the Dominion Reef Group, the Witwatersrand Supergroup, and the Ventersdorp Contact Reef, with particular reference to the close relationship of gold and uranium with sedimentary features as well as the mineralization, conditions of deposition, and the nature of the quartz-pebble conglomerates

  9. Green for rarity

    International Nuclear Information System (INIS)

    Raal, F.A.; Robinson, D.N.

    1980-01-01

    Green diamonds once recovered from Witwatersrand gold/uranium deposits, are now a thing of the past with the modernisation of extraction metallurgy methods. The green colouration has been shown to be due to radiation from uranium present in the ore

  10. survey of opinions in a paediatric department

    African Journals Online (AJOL)

    1991-05-04

    May 4, 1991 ... Doctors working at 3 teaching hospitals of the University of the Witwatersrand were .... study. It can therefore be assumed that the opinions put forth were largely .... and will, it is hoped, provide some food for thought for other departments. ... Puhlic Health 'Service guidelioes for counselliog and antibody ...

  11. SAMJ 8619.indd

    African Journals Online (AJOL)

    the position of the graft. ... Wits Donald Gordon Medical Centre, University of the Witwatersrand, ... There is a significant risk of complications after all forms of liver transplantation. ... the peak velocity above 2 m/s at the site of ... highly variable, but is ~5% in high-performing .... mass effect, collections can be aspirated or a.

  12. 78 FR 49769 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Telemanagement Forum

    Science.gov (United States)

    2013-08-15

    ... the Attorney General and the Federal Trade Commission disclosing changes in its membership. The...; Innova Bilisim Cozumleri, Maslak, TURKEY; Intelli Solutions S.A., Athens, GREECE; International IT House..., GERMANY; Synopsis S.A., Lima, PERU; Trendium, Boulder, CO; University of Witwatersrand, School of...

  13. Research Success and Structured Support: Developing Early Career Academics in Higher Education

    Science.gov (United States)

    Geber, H.

    2009-01-01

    Entry into a successful academic career is often an arduous process. From career preparation through to doctoral studies and beyond, the journey can be fraught with trials. Why do many academics find difficulty in completing their studies in the minimum time and publishing afterwards? As the University of the Witwatersrand has a strategic goal of…

  14. Restandardisation defined as democratising language planning1

    African Journals Online (AJOL)

    dignity. Furthermore, globalisation gave rise to a worldwide ethnic renaissance with a focus on ... Given this democratisation of the world, the relevance of standard ...... extinction. The harmonisation and standardisation of African languages. Johannesburg: Witwatersrand University Press. pp. 157-164. Mantho, E. 2009.

  15. from Anatase to Rutile Nanorods

    African Journals Online (AJOL)

    NJD

    thermal6,7) lyophilization, laser ablation, electrodeposition and a range of ... nucleation,5,16 surface protection,15,16,23 and proposals that the reaction can fall ..... Nanoparticles, M.Sc. thesis, University of the Witwatersrand, Johan- nesburg ...

  16. Haematoma in the secondary to acute transverse mesocolon ...

    African Journals Online (AJOL)

    1983-04-09

    Apr 9, 1983 ... extension of the inflammatory process into the anterior pararenal spaces and small-bowel mesentery; there was some penetration of Gerota's fascia of the right kidney (Figs I and 2). There was. Departments of 'Diagnostic Radiology and Surgery,. Baragwanath Hospital and University of the Witwatersrand,.

  17. Assessing the impact of academic support: University of the ...

    African Journals Online (AJOL)

    On average the B.Sc. (Eng.) degree programmes in South Africa universities graduate about 50±60 per cent of the students admitted. Generally, the highest dropout occurs in the first year of registration. This article reviews admission and graduation statistics at the University of the Witwatersrand (Wits) and assesses the ...

  18. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    2001-08-09

    Aug 9, 2001 ... Perception of asthma. Lancet 1976; I: .... Chemosensitivity and perception of dyspnoea in patients .... The reverse is true when the prevalence increases. .... One of the most useful characteristics of logistic regression is .... Women's Health Project, School of Public Health, University of the Witwatersrand,.

  19. Singing South Africanness: the construction of identity among South ...

    African Journals Online (AJOL)

    South Africa has a vibrant and well-developed choral music scene that incorporates many musical genres and is evident in most, if not all, sectors of South African society. In this pilot study, which focuses on the choir of the University of the Witwatersrand, I investigate the relationship between the identity that choristers ...

  20. Exploring the validity of the continuous assessment strategy in ...

    African Journals Online (AJOL)

    ... subject areas such as mathematics and science. This article outlines how a Continuous Assessment (CASS) mechanism introduced in the second year mathematics for civil engineering students at Technikon Witwatersrand could attain the desired goals. South African Journal of Higher Education Vol.18(2) 2004: 302-312 ...

  1. Conceptualising Transformation and Interrogating Elitism: The Bale Scholarship Programme

    Science.gov (United States)

    Botsis, Hannah; Dominguez-Whitehead, Yasmine; Liccardo, Sabrina

    2013-01-01

    In this article, we consider the extent to which a scholarship programme at the University of the Witwatersrand (Wits) engages with the challenges of transformation. This scholarship programme highlights the transformative potential of a programme that focuses on excellence for a previously under-represented group, but also demonstrates how this…

  2. WHAT ARE THE MOLECULES DOING?

    African Journals Online (AJOL)

    Temechegn

    University of the Witwatersrand, Johannesburg, South Africa ... [African Journal of Chemical Education—AJCE 6(2), July 2016] ... understand science concepts: in essence these are macroscopic (phenomena), microscopic .... than the simple freeing up of already-existing smaller molecules: this implies a high melting point.

  3. Introductory Geological Mapwork--An Active Learning Classroom

    Science.gov (United States)

    Drennan, Gillian R.; Evans, Mary Y.

    2011-01-01

    First year Geology students at the University of the Witwatersrand experience problems with both three-dimensional and "four-dimensional" (or time) visualization when attempting to interpret geological maps. These difficulties have been addressed by the introduction of hands-on modeling exercises, which allow students to construct…

  4. The development of GIS-PMWIN and its application for mine-water ...

    African Journals Online (AJOL)

    compatible files which can be directly loaded to PMWIN for modelling. The linkage can be used with a higher version of PMWIN or ArcGIS. It has been applied to mine water modelling in the Far West Rand of the Witwatersrand basin to simulate ...

  5. Treatment of psoriasis with cyclosporin

    African Journals Online (AJOL)

    within 2 months but relapsed, either while the dose of CyA was being tapered off or after treatment with the drug was ... and bone marrow transplantation.' It has also shown promising results in the treatment of ... Division of Dermatology, Department of Medicine, Johannesburg. Hospital and University of the Witwatersrand, ...

  6. Timing of antenatal care and ART initiation in HIV-infected pregnant ...

    African Journals Online (AJOL)

    3 Health and Development Africa, Mott MacDonald South Africa. 4 Epidemiology and Biostatistics Unit, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand,. Johannesburg, South Africa. 5 Department of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, South Africa.

  7. A South African corrosion research contribution

    International Nuclear Information System (INIS)

    Robinson, F.P.A.

    1980-01-01

    This paper contains the historical background to the setting up of the S.A. Corrosion Institute. The Metallurgy Department of the University of the Witwatersrand has been a training ground for corrosion scientists and engineers. Most of the research and development carried out has been devoted to stainless steels and more particularly to studying the effects of different alloying elements

  8. The annual pattern of sap flow in two Eucalyptus species ...

    African Journals Online (AJOL)

    Several hundred mine tailings dams occur in the Witwatersrand Basin Goldfields in central South Africa. Seepage of acid mine drainage (AMD) from these unlined structures is widespread, and a variety of contaminants is released into soil and groundwater. The 'Mine Woodlands Project' is aimed at evaluating the use of ...

  9. Visual deterioration 1½ years after wrapping an un-clippable ...

    African Journals Online (AJOL)

    2005-09-02

    Sep 2, 2005 ... C/O Division of Neurosurgery, Department of Neurosciences,. University of the Witwatersrand, 7 York Rd. Parktown 2193,. Johannesburg, South Africa email: jmno@mweb.co.za. Visual deterioration 1½ years after wrapping an un-clippable anterior communicating artery aneurysm: report of a case and.

  10. I:\\AA-TYPESET\\CHEM\\2006\\Van Es.vp

    African Journals Online (AJOL)

    NJD

    aDepartment of Biochemistry and Microbiology, Cook College, Rutgers, The State University of New Jersey, 08903-0231, USA. bSchool of Chemistry, University of the Witwatersrand, Johannesburg, South Africa. cVisiting Associate, Department of Chemistry and Biomolecular Sciences, Macquarie University, NSW 2109, ...

  11. Contribution of ENPP1, TCF7L2, and FTO polymorphisms to type 2 ...

    African Journals Online (AJOL)

    Department of Surgery, Faculty of Health Sciences, University of Witwatersrand, South Africa. 2. Department of Biomedical Sciences Faculty of Health and Wellness Sciences, Cape Peninsula. University of Technology, Cape Town, South Africa. 3. Non-Communicable Diseases Research Unit, South African Medical ...

  12. Assessing academic potential for university admission: The ...

    African Journals Online (AJOL)

    A Biographical Questionnaire (BQ) has been used in the Faculty of Humanities at the University of the Witwatersrand since the mid-80s, to identify potential to succeed at university among applicants who have not met the requirements for automatic admission. As the key instrument in a special admissions process, the

  13. Testing for haemoglobinopathies in Johannesburg, South Africa: A ...

    African Journals Online (AJOL)

    ... National Health Laboratory Service and University of the Witwatersrand, from 1983 ... was IVS1 nt5 (G>C) (c.92+5G>C) and in individuals from the Mediterranean, ... haemoglobinopathies occur at significant frequencies in specific high-risk ...

  14. SAHARA MAKEUP NOV 07

    African Journals Online (AJOL)

    Winnie

    Mots clés: CDV,VIH, genre. Kennedy Otwombe is currently a PhD student in statistics at the University of the Witwatersrand with an interest in the application of statistics in health research. His current interest is in monitoring and evaluation of HIV related studies and the analysis of incomplete data in longitudinal studies.

  15. A clinico-pathologic review of 56 cases of ossifying fibroma of the ...

    African Journals Online (AJOL)

    Materials and Methods: A total of 80 patients who were diagnosed either as cementifying fibroma CF, OF and cemento.ossifying fibroma (COF) of the jaws from the files of the Oral Pathology Department of the University of the Witwatersrand Dental School were retrieved and the histology slides of each case were reviewed ...

  16. Wits University's response to HIV/AIDS: flagship programme or ...

    African Journals Online (AJOL)

    HIV/AIDS is a threat to the creation of human capital and development prospects in southern Africa and South Africa. The University of the Witwatersrand (Wits) is a well-regarded institution of higher education in Johannesburg. This paper outlines the university's qualified failure to implement its HIV/AIDS Policy through a ...

  17. Philosophical Papers: Editorial Policies

    African Journals Online (AJOL)

    Brian McLaughlin (Rutgers) Chris Megone (Leeds) Seumas Miller (Charles Sturt) Ruth Garrett Millikan (Connecticut) Michael Pendlebury (Witwatersrand) John Perry (Stanford) Philip Pettit (Australian National University) Amélie Oksenberg Rorty (Brandeis) Mark Sainsbury (Texas—Austin) John Searle (California Berkeley)

  18. The evaluation of bedside teaching – an instrument for staff ...

    African Journals Online (AJOL)

    Bedside teaching is the core teaching strategy in the clinical study years of the medical undergraduate degree at the University of the Witwatersrand. ... evaluation questionnaire was developed, based on previously validated peer review questionnaires used in evaluating small group formal classroom-based lectures.

  19. Student feedback on an adapted appraisal model in resource ...

    African Journals Online (AJOL)

    Background. An appraisal model, a type of formal mentorship programme for a cohort of student doctors, is used at the University of Leeds, UK. The University of the Witwatersrand, Johannesburg, South Africa implemented an adapted version of the appraisal process that uses fewer resources. Objective. To explore ...

  20. Making connections through reflection: writing and feedback in an ...

    African Journals Online (AJOL)

    This paper describes the writing and feedback processes in an academic literacy course for first-year students in an extended studies programme at the University of the Witwatersrand in Johannesburg. We argue that feedback together with metacognitive reflection form a 'vital link' between students' early experiences of a ...

  1. Paving the Road to Success: A Framework for Implementing the ...

    African Journals Online (AJOL)

    This paper outlines an approach called Success Tutoring (a non-academic tutorial approach used as part of a student success and support programme in the Faculty of Commerce, Law, and Management at the University of the Witwatersrand), which is underscored by empirical evidence drawn from evaluation data ...

  2. Growth, carcase and meat characteristics of stress susceptible and ...

    African Journals Online (AJOL)

    Growth, carcase and meat characteristics of stress susceptible and stress resistant. South African Landrace gilts. P.H. Heinze*. Animal and Dairy Science Research Institute, Private Bag X2, Irene, 1675Republic of South Africa. G. Mitchell. Department of Physiology, Medical School, University of the Witwatersrand, York ...

  3. Journal for the Study of Religion - Vol 28, No 2 (2016)

    African Journals Online (AJOL)

    The moral rearmament activist: P.Q. Vundla's community bridge-building during the boycotts on the Witwatersrand in the mid-1950s · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Garth Mason, 154 – 180 ...

  4. On a problem of Pillai with Fibonacci numbers and powers of 2

    Indian Academy of Sciences (India)

    On a problem of Pillai with Fibonacci numbers and powers of 2. MAHADI DDAMULIRA1,∗, FLORIAN LUCA2 and MIHAJA RAKOTOMALALA3. 1Institute of Analysis and Number Theory, Graz University of Technology,. A-8010 Graz, Steyrergasse 30/II, Austria. 2School of Mathematics, University of the Witwatersrand, Private ...

  5. Co-occurrence of mated workers and a mated queen in a colony of ...

    African Journals Online (AJOL)

    arnoldi (Hymenoptera: Formicidae). Martin Villet *. Department of Zoology, University of the Witwatersrand, P.O.. Wits, 2050 Republic of South Africa. Received 23 March 1992; accepted 8 June 1992. A colony of Platythyrea arnold; was found to contain a functional queen and laying workers, both virgin and mated. This form ...

  6. Review: Long-term sustainability in the management of acid mine ...

    African Journals Online (AJOL)

    decanting of flooded gold mines threatens water supply on the Witwatersrand, South Africa, one of the most intensively mined areas in the world. Large volumes of acid mine drainage wastewaters will require treatment here for decades and possibly centuries. Appropriate treatment technology needs to meet technical, ...

  7. Water SA - Vol 33, No 2 (2007)

    African Journals Online (AJOL)

    Microbiological, physico-chemical and management parameters impinging on the efficiency of small water treatment plants in the Limpopo and Mpumalanga Provinces of ... An investigation into the availability and role of oxygen gas in gold tailings dams of the Witwatersrand basin with reference to their acid mine drainage ...

  8. Improving Performance in a Second Year Chemistry Course: An ...

    African Journals Online (AJOL)

    NJD

    Improving Performance in a Second Year Chemistry. Course: An Evaluation of a Tutorial Scheme on the. Learning of Chemistry. Bette Davidowitza* and Marissa Rollnickb**. aDepartment of Chemistry, University of Cape Town, South Africa. bSchool of Education, University of Witwatersrand, South Africa. Received 11 ...

  9. Can improving teachers' knowledge of mathematics lead to gains in ...

    African Journals Online (AJOL)

    10218122

    2015-08-05

    Aug 5, 2015 ... Wits School of Education, Faculty of Humanities, University of the Witwatersrand, South Africa ... and Science Study (TIMSS), Programme for International Student Assessment (PISA), Southern Africa .... (2012) report the effects of a study in which middle ... existing knowledge of the mathematics at hand.

  10. The identification of provenance-controlled facies by geochemical methods on a portion of the Vaal Reef, Klerksdorp Goldfield

    International Nuclear Information System (INIS)

    Henckel, J.; Schweitzer, J.K.; Horsch, H.

    1990-01-01

    The use of geochemical methods for identifying provenance controlled facies in Witwatersrand reefs is considered. Three methods - whole rock geochemistry, zircon analysis, and chromite analysis - have been evaluated in order to establish the feasibility of using these geochemical techniques. An area of Vaal Reef where two sedimentological facies with distinct gold distributions had previously been identified was investigated. The studies reported here gave evidence of differences in the source areas for these two facies. Accordingly, it is concluded that the application of geochemistry to identify provenance-controlled facies is a useful technique which can help geologists arrive at a better interpretation of depositional systems within Witwatersrand reefs and thereby assist in the understanding of gold distribution patterns. 26 refs., 11 figs., 4 tabs

  11. Defining pyromes and global syndromes of fire regimes

    CSIR Research Space (South Africa)

    Archibald, S

    2013-04-01

    Full Text Available . Bradstocke aNatural Resources and the Environment, Council for Scientific and Industrial Research, Pretoria 0001, South Africa; bSchool of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa; c...Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia; dNational Centre for Earth Observation and Department of Geography, University College London, London WC1E 6BT, United Kingdom; and eInstitute for Conservation Biology...

  12. Online constrained model-based reinforcement learning

    CSIR Research Space (South Africa)

    Van Niekerk, B

    2017-08-01

    Full Text Available Constrained Model-based Reinforcement Learning Benjamin van Niekerk School of Computer Science University of the Witwatersrand South Africa Andreas Damianou∗ Amazon.com Cambridge, UK Benjamin Rosman Council for Scientific and Industrial Research, and School... MULTIPLE SHOOTING Using direct multiple shooting (Bock and Plitt, 1984), problem (1) can be transformed into a structured non- linear program (NLP). First, the time horizon [t0, t0 + T ] is partitioned into N equal subintervals [tk, tk+1] for k = 0...

  13. How the International Research Institute for Climate and Society has contributed towards seasonal climate forecast modelling and operations in South Africa

    CSIR Research Space (South Africa)

    Landman, WA

    2014-06-01

    Full Text Available of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africatems for rainfall (Mason 1998, Jury et al. 1999) and for temperature (Klopper et al. 1998). In fact, a number of institutions in South Africa initially developed statis...- tical prediction systems: the South African Weather Service (Landman and Mason 1999a), the University of the Witwatersrand (Mason 1998) and the University of Cape Town (Jury et al. 1999). A few years later South (South African Weather Service) as a...

  14. Water demand prediction using artificial neural networks and support vector regression

    CSIR Research Space (South Africa)

    Msiza, IS

    2008-11-01

    Full Text Available Neural Networks and Support Vector Regression Ishmael S. Msiza1, Fulufhelo V. Nelwamondo1,2, Tshilidzi Marwala3 . 1Modelling and Digital Science, CSIR, Johannesburg,SOUTH AFRICA 2Graduate School of Arts and Sciences, Harvard University, Cambridge..., Massachusetts, USA 3School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, SOUTH AFRICA Email: imsiza@csir.co.za, nelwamon@fas.harvard.edu, tshilidzi.marwala@wits.ac.za Abstract— Computational Intelligence techniques...

  15. Quantification of Inherent Respirable Dust Generation Potential (IRDGP) of South African Coals

    CSIR Research Space (South Africa)

    Phillips, H

    2003-08-01

    Full Text Available Advisory Committee Project Summary Project Title: Inherent Respirable Dust Generation Potential (IRDGP) of South African Coals-SIM020604 Author(s): H.R.Phillips and B. K. Belle Agency: University of Witwatersrand Report Date: July2003... Related Projects: Health 607, Sim 02-06-03 Category: Occupational Health Applied Research Occupational Hygiene Summary Project SIM020604 was formulated to determine the Inherent Respirable Dust Generation Potential (IRDGP) of various South...

  16. Leaching of rare earth elements from bentonite clay

    OpenAIRE

    van der Watt, J.G; Waanders, F.B

    2012-01-01

    Due to increasing concerns of global rare earth element shortfalls in the near future, possible alternative sources of rare earth elements have recently become of economic interest. One such alternative is decanting acid mine water originating primarily from abandoned old mines in the Witwatersrand region of the Republic of South Africa. In this study, a novel way of rare earth element removal from the acid mine drainage was employed, making use of bentonite clay, which has very good adsorben...

  17. Unsustainable fuelwood extraction from South African savannas

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2013-01-01

    Full Text Available Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA 4 Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, Wits... Supplies in the Developing Countries (Forestry Paper No. 42) (Rome: Food and Agriculture Organisation) Dewees P A 1989 The woodfuel crisis reconsidered: observations on the dynamics of abundance and scarcity World Dev. 17 1159–72 Dovie D B K, Shackleton C M...

  18. Is Planning Paying Attention to "the future?" Experiences in Eight South African Municipalities

    CSIR Research Space (South Africa)

    Petzer, Engela

    2016-07-01

    Full Text Available Province Zandile Nkosi, Gauteng Province Willemien van Niekerk, CSIR Peter Dacomb, The Planning Practice Group Fana Sihlongonyane, University of Witwatersrand Herman Pienaar, City of Johannesburg Geci Karuri-Sebina, SACN Scientific Committee... and Evaluation Assessment Tool Report of Results 2011/2012 highlights the need for improved project management practices that are key for improving local government performance and service delivery (RSA 2011: 10). However, a significant number of South...

  19. The recovery of uranium, gold and sulphur from residues from South African mines

    International Nuclear Information System (INIS)

    Toens, P.D.

    1978-10-01

    The slimes dams resulting from the operations of gold and gold/uranium mines situated within the Witwatersrand Basin contain low concentrations of gold, uranium and pyrite. As a result of a marked increase in the prices of both gold and uranium in recent years, two schemes involving the recovery of these minerals also the manufacture of sulphuric acid as a by-product are operating profitably. Further schemes are under investigation [af

  20. Exploration of the biomacromolecular interactions of an interpenetrating proteo-saccharide hydrogel network at the mucosal interface

    CSIR Research Space (South Africa)

    Mashingaidze, F

    2013-09-01

    Full Text Available EXPLORATION OF THE BIOMACROMOLECULAR INTERACTIONS OF AN INTERPENETRATING PROTEO-SACCHARIDE HYDROGEL NETWORK AT THE MUCOSAL INTERFACE 1Felix Mashingaidze, 1Yahya E. Choonara, 1Pradeep Kumar, 1Lisa C. du Toit, 2Vinesh Maharaj, 3Eckhart Buchmann, 4Valence M..., Department of Biosciences, Meiring Naud_e Road, Brummeria, Pretoria, South Africa 3University of the Witwatersrand, Faculty of Health Sciences, Department of Obstetrics and Gynecology, 7 York Road, Parktown, 2193, Johannesburg, South Africa 4St. John’s...

  1. The Bottom Line : Industry and the Environment in South Africa ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Bottom Line est le fruit de trois années de recherches effectuées par le Projet sur la stratégie industrielle de l'Université du Cap. ... Michael Goldblatt est gestionnaire du Programme Environnement et développement à l'École d'études supérieures en gestion publique et développement de l'Université de Witwatersrand, ...

  2. Frequency of hepatitis B (HBV) viral markers in sixth year dental students after three years clinical exposure

    Energy Technology Data Exchange (ETDEWEB)

    Buxt, P; Fairbairn, P J.M.; Stern, S R; Treisman, B [University of the Witwatersrand, Johannesburg (South Africa). Dept. of Oral Pathology

    1981-08-01

    The frequency of Hepatitis B viral markers was studied in 40 6th year dental students at the University of the Witwatersrand, Johannesburg, after three years clinical exposure, using the radioimmunoassay technique. Three were anti-HBs positive; none was HBsAg positive. The frequency of the anti-HBs positive cases did not differ significantly from a group of blood donors, nor were there any statistically significant associated risk factors.

  3. Reviews

    OpenAIRE

    de Kadt, Elizabeth

    1998-01-01

    Obres ressenyades: Vivian DE KLERK (ed.). Focus on South Africa. Amsterdam/Philadelphia: John Benjamins, 1996; Kathleen HEUGH, Amanda SIEGRÜHN and Peter PLÜDDEMANN (eds.). Multilingual Education for South Africa. Johannesburg: Heinmann, 1995; Russell H. KASCHULA and Christine ANTHONISSEN. Communicating Across Cultures in South Africa: Towards a Critical Language Awareness. Johannesburg etc.: Hodder & Stoughton, and Witwatersrand University Press, 1995; L.W. LANHAM, David LANGHAM, Arie BLACQUI...

  4. Exploring the Perceptions of Wits Academic Women About Women Empowerment and the Changing Roles of Women in 21st-Century South Africa

    OpenAIRE

    Evelyn Muberekwa; Thobeka Nkomo

    2016-01-01

    Issues of women’s empowerment and gender inequality have been of paramount importance, particularly in the two decades since the Fourth World Conference on Women, Beijing, 1995. At that conference, the campaign for women’s empowerment was initiated to implement laws promoting gender equality. This research explored the perceptions of nine academic women at the University of the Witwatersrand with regard to women’s empowerment and the changing roles of women in a South African context in the 2...

  5. The frequency of hepatitis B (HBV) viral markers in sixth year dental students after three years clinical exposure

    International Nuclear Information System (INIS)

    Buxt, P.; Fairbairn, P.J.M.; Stern, S.R.; Treisman, B.

    1981-01-01

    The frequency of Hepatitis B viral markers was studied in 40 6th year dental students at the University of the Witwatersrand, Johannesburg, after three years clinical exposure, using the radioimmunoassay technique. Three were anti-HBs positive; none was HBsAg positive. The frequency of the anti-HBs positive cases did not differ significantly from a group of blood donors, nor were there any statistically significant associated risk factors [af

  6. Optical trapping and tweezing using a spatial light modulator

    CSIR Research Space (South Africa)

    Ismail, Y

    2009-07-01

    Full Text Available using a spatial light modulator Y.Ismail1,2, M. G. Mclaren1,3, A. Forbes1,2,4 1 CSIR National Laser Centre 2 School of Physics, University of KwaZulu-Natal 3 School of Physics, University of the Witwatersrand 4 School of Physics, University... of Stellenbosch Presented at the 2009 South African Institute of Physics Annual Conference University of KwaZulu-Natal Durban, South Africa 6-10 July 2009 Optical tweezing is based on the manipulation of micron sized particles in 3 dimensions 100X...

  7. Vaal River catchment: problems and research needs

    CSIR Research Space (South Africa)

    Braune, E

    1987-01-01

    Full Text Available , the Pretoria-Witwatersrand-Vereeniging (PWV) complex. Although the catchment only produces eight per cent of the mean annual runoff of the country it has the highest concentration of urban, industrial, mining and power generation development in South Africa... of the Vaal River. The purpose of the workshop and preceding symposium was to examine the ever increasing complexity of the Vaal River system, the much enlarged spectrum of user water quality needs and problems, and those activities in the catchment which...

  8. Survey and assessment of support for non-standard (anomalous) stope areas in the gold and platinum industry.

    CSIR Research Space (South Africa)

    Leach, AR

    2002-12-01

    Full Text Available of depth below surface Figure 2.5 Contributing factors to 89 accident incidents as a function of reef Figure 2.6 Relative proportion of key factors contributing to anomalous conditions on the VCR, as determined from 28 incidents Figure 3.1 Location... to correctly recognise and address problems. The project considers gold mines in the Witwatersrand basin and platinum mines in the Bushveld Igneous Complex, at all depths from near surface to in excess of 3500 m, on a range of economically important reefs...

  9. An investigation of the impurities in native gold by neutron-activation analysis

    International Nuclear Information System (INIS)

    Erasmus, C.S.; Sellschop, J.P.F.; Hallbauer, D.K.; Novak, E.

    1980-01-01

    Instrumental and radiochemical methods of neutron-activation analysis, developed for the determination of major, minor, and trace impurities in native gold, are described. The gold was obtained from Witwatersrand reefs and from deposits in the Barberton area. It was extracted by decomposition of the ore in cold hydrofluoric acid. Quantitative results are presented for 14 elements found in native gold, and the significance of these elements in relation to the distribution of gold is discussed. The results suggest that there are geochemical differences in native gold from various reefs and deposits

  10. High-dimensional quantum channel estimation using classical light

    CSIR Research Space (South Africa)

    Mabena, Chemist M

    2017-11-01

    Full Text Available stream_source_info Mabena_20007_2017.pdf.txt stream_content_type text/plain stream_size 960 Content-Encoding UTF-8 stream_name Mabena_20007_2017.pdf.txt Content-Type text/plain; charset=UTF-8 PHYSICAL REVIEW A 96, 053860... (2017) High-dimensional quantum channel estimation using classical light Chemist M. Mabena CSIR National Laser Centre, P.O. Box 395, Pretoria 0001, South Africa and School of Physics, University of the Witwatersrand, Johannesburg 2000, South...

  11. Analysis of non-axisymmetric wave propagation in a homogeneous piezoelectric solid circular cylinder of transversely isotropic material

    CSIR Research Space (South Africa)

    Shatalov, MY

    2009-01-01

    Full Text Available ). The main disadvantage of this approach is that the roots of characteristic arguments ( ( )0, 1, , 4k kξ = = … ) are also displayed on the surface plots as obvious artefacts. An elaborate discussion of these artefacts is given in Yenwong-Fai (2008...-matrix interface by guided waves: Axisymmetric case. J. Acoust. Soc. Am 89 (6), 2573-2583. Yenwong-Fai, A., 2008. Wave propagation in a piezoelectric solid cylinder of transversely isotropic material. Master’s thesis, University of Witwatersrand, Johannesburg...

  12. Application of borehole radar to South Africa’s Ultra-Deep gold mining environment

    CSIR Research Space (South Africa)

    Trickett, JC

    2000-05-01

    Full Text Available ), the collar of which is located at a depth of 3.3 km below datum1. LIB boreholes are used to probe totally undeveloped blocks of ground and, being semi-parallel to reef, are ideal for the application of Borehole Radar. By applying Borehole Radar from... the target reef; viz. 1 For the Witwatersrand Basin Gold Mines, the datum is ? 1829 m above sea level. Ventersdorp Contact Reef (VCR), twice. It was drilled at 45? downwards into the hangingwall...

  13. Dry deposition of sulphur at a high-altitude background station in South Africa

    CSIR Research Space (South Africa)

    Zunckel, M

    1999-10-01

    Full Text Available station also plays a role in the observed day-to-day variation as pollutants are trapped immediately below this layer. The pressure difference between the base of the absolutely stable layer and the surface pressure at Ben MacDhui is used to indicate... AT A HIGH-ALTITUDE BACKGROUND STATION IN SOUTH AFRICA MARK ZUNCKEL1;2 , STUART PIKETH1 and TALI FREIMAN1 1 Climatology Research Group, University of Witwatersrand, Johannesburg, South Africa; 2 CSIR Environmentek, P.O. Box 17001, Congella, South Africa...

  14. Enantioselective biocatalytic hydrolysis of ß-aminonitriles to ß-amino-amides using Rhodococcus rhodochrous ATCC BAA-870

    CSIR Research Space (South Africa)

    Chhiba, V

    2012-04-01

    Full Text Available . ?Current address: School of Chemistry, University of the Witwatersrand, PO Wits 2050, South Africa. *Corresponding author. CSIR Biosciences, Private bag X2, Modderfontein, 1645, South Africa. Tel +27-82-467- 6209. E-mail address: dbrady... of the achiral ?-alanine from the respective nitrile, and found that conversion proceeded better at pH 7.5 than pH 6.0, although higher a pH was not tested. The aryl methyl substituted nitrile had a maximum enantiomeric ratio (E) of 7.7 and the amide of 4...

  15. Ram pressure statistics for bent tail radio galaxies

    CSIR Research Space (South Africa)

    Mguda, Z

    2015-01-01

    Full Text Available ), Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa 2South African Astronomical Observatory (SAAO), PO Box 9, 7935 Observatory, Cape Town, South Africa 3Department of Physics, University of Witwatersrand... Published by Oxford University Press on behalf of the Royal Astronomical Society at South A frican A stronom ical O bservatory on D ecem ber 18, 2014 http://m nras.oxfordjournals.org/ D ow nloaded from Statistics for bent radio sources 3311 are left for a...

  16. Measuring microscopic forces and torques using optical tweezers

    CSIR Research Space (South Africa)

    Mc

    2009-07-01

    Full Text Available stream_source_info McLaren_2009.pdf.txt stream_content_type text/plain stream_size 2976 Content-Encoding UTF-8 stream_name McLaren_2009.pdf.txt Content-Type text/plain; charset=UTF-8 Measuring microscopic forces... and torques using optical tweezers M.G. McLaren1,2, A. Forbes2,3,4 and E. Sideras-Haddad2 1 CSIR National Laser Centre 2 School of Physics, University of Witwatersrand 3 School of Physics, University of KwaZulu-Natal 4 School of Physics, University...

  17. An analysis of Monte Carlo tree search

    CSIR Research Space (South Africa)

    James, S

    2017-02-01

    Full Text Available Tree Search Steven James∗, George Konidaris† & Benjamin Rosman∗‡ ∗University of the Witwatersrand, Johannesburg, South Africa †Brown University, Providence RI 02912, USA ‡Council for Scientific and Industrial Research, Pretoria, South Africa steven....james@students.wits.ac.za, gdk@cs.brown.edu, brosman@csir.co.za Abstract Monte Carlo Tree Search (MCTS) is a family of directed search algorithms that has gained widespread attention in re- cent years. Despite the vast amount of research into MCTS, the effect of modifications...

  18. Do we have an acceptable model of power-law creep?

    CSIR Research Space (South Africa)

    Nabarro, FRN

    2004-12-15

    Full Text Available 387–389 (2004) 659–664 Do we have an acceptable model of power-law creep? F.R.N. Nabarro a,b,∗ a Condensed Matter Physics Research Group, School of Physics, University of the Witwatersrand, Private Bag 3, Johannesburg WITS 2050, South Africa b... an exponential function 0921-5093/$ – see front matter © 2004 Published by Elsevier B.V. doi:10.1016/j.msea.2003.09.118 660 F.R.N. Nabarro / Materials Science and Engineering A 387–389 (2004) 659–664 of the stress. There is little evidence whether the physical...

  19. Hydrogen in metals

    CSIR Research Space (South Africa)

    Carter, TJ

    2001-04-01

    Full Text Available .J. Cartera,*, L.A. Cornishb aAdvanced Engineering & Testing Services, MATTEK, CSIR, Private Bag X28, Auckland Park 2006, South Africa bSchool of Process and Materials Engineering, University of the Witwatersrand, Private Bag 3, P.O. WITS 2050, South Africa... are contrasted, and an unusual case study of hydrogen embrittlement of an alloy steel is presented. 7 2001 Published by Elsevier Science Ltd. Keywords: Hydrogen; Hydrogen-assisted cracking; Hydrogen damage; Hydrogen embrittlement 1. Introduction Hydrogen suC128...

  20. Improving public health training and research capacity in Africa: a replicable model for linking training to health and socio-demographic surveillance data

    Directory of Open Access Journals (Sweden)

    Jill R. Williams

    2010-08-01

    Full Text Available Background: Research training for public health professionals is key to the future of public health and policy in Africa. A growing number of schools of public health are connected to health and socio-demographic surveillance system field sites in developing countries, in Africa and Asia in particular. Linking training programs with these sites provides important opportunities to improve training, build local research capacity, foreground local health priorities, and increase the relevance of research to local health policy. Objective: To increase research training capacity in public health programs by providing targeted training to students and increasing the accessibility of existing data. Design: This report is a case study of an approach to linking public health research and training at the University of the Witwatersrand. We discuss the development of a sample training database from the Agincourt Health and Socio-demographic Surveillance System in South Africa and outline a concordant transnational intensive short course on longitudinal data analysis offered by the University of the Witwatersrand and the University of Colorado-Boulder. This case study highlights ways common barriers to linking research and training can be overcome. Results and Conclusions: This collaborative effort demonstrates that linking training to ongoing data collection can improve student research, accelerate student training, and connect students to an international network of scholars. Importantly, the approach can be adapted to other partnerships between schools of public health and longitudinal research sites.

  1. Some aspects of the genesis of heavy mineral assemblages in Lower Proterozoic uranium-gold conglomerates

    International Nuclear Information System (INIS)

    Clemmey, H.

    1982-01-01

    Some genetic models for Lower Proterozoic gold- and uranium-bearing pyritic conglomerates favour a modified placer origin in which low levels of atmospheric oxygen are used to account for the survival of uraninite and pyrite. There are many difficulties with such models. New evidence concerning the genesis of the deposits is derived from a clast of ferric iron clay thought to represent a precursor sediment of the Witwatersrand Basin. Reworking of such clays and transport of a magnetite and ferric clay assemblage with subsequent sulphidation, could account for the porous pyrites, the absence of magnetite and the lack of hydraulic equivalence of the mineral grains in the conglomerates. The presence of oxygen, as indicated by the ferric iron clasts, would account for the evidence of mobility of uranium and of gold and would enhance their extraction from source rocks; particularly the release of gold from a precursor auriferous iron formation source. It is suggested that some aspects of the genesis of uranium deposits of the Witwatersrand and Elliott Lake may be similar to those of the Phanerozoic 'Roll Front' ores involving interaction between oxidizing uraniferous groundwaters and previously sulphidized and reduzate facies sediments. (author)

  2. New evidence on the composition of mineral grains of native gold

    International Nuclear Information System (INIS)

    Erasmus, C.S.; Sellschop, J.P.F.; Watterson, J.I.W.

    1987-01-01

    The nuclear analytical techniques of instrumental neutron activation and radiochemical neutron activation have been applied to the analysis of native gold from the Precambrian Witwatersrand Sequence and from the Archaen deposits in the Barberton Mountain Land, Murchison Range and Pietersburg region in South Africa. A total of 15 elements were determined in the samples of native gold, namely: scandium, iron, cobalt, nickel, copper, zinc, zirconium, silver, antimony, tellurium, cerium, europium, ytterbium, mercury and thorium. Of these the silver and mercury were determined by the instrumental procedure and the copper was determined after extraction with diethyl dithiocarbamate. The other elements were determined from long-lived isotopes after the removal of silver by dissolution of the gold and precipitation of the silver as silver iodide. The most significant result of this work is the discovery that mercury occurs at the percentage level in native gold from the Witwatersrand (between 1 and 5%), demonstrating the power of the nuclear method in comparison with conventional methods such as optical spectroscopy and the electron microprobe, which had failed to make this discovery. (author)

  3. Archives in the reefs

    International Nuclear Information System (INIS)

    Smits, G.

    1985-01-01

    The history of our planet and its inhabitants and the broad trends in the evolution of the earth and its 'spheres' can be reconstructed from terrestrial records written in sedimentary rocks. As an example of the actualistic approach used in interpreting these records, an attempt is made to reconstruct the depositional environment of the Witwatersrand deposits of Proterozoic age in the light of the occurrences of uranium and gold deposits found. Sedimentary rocks are the only source of useful information on the physico-chemical conditions that prevailed on the surface of the earth. It is generally assumed that the atmosphere was deficient in oxygen during the Early Proterozoic. Evidence thereof can be derived from mineralogical features of which the most commonly cited are the preservation of primary uraninite and pyrite of detrital origin. In an oxidising environment, uraninite is chemically reactive and the concentration of uranium is characterized by redox processes. The oxidation of uranium during weathering may lead to dispersal of uranium. The large amounts of uraninite present indicate that the dissolution of uranium was limited. Primitive plants in the Witwatersrand sediments played an essential role in the physical concentration of gold and uraninite

  4. Uranium processing in South Africa from 1961 to 1981

    International Nuclear Information System (INIS)

    Boydell, D.W.; Viljoen, E.B.

    1982-01-01

    The production of uranium in South Africa reached a peak of 5,846 kt of U 3 O 8 in 1959, when 17 plants treated material from a total of 27 mines. By 1965 production had fallen to 2,669 kt of U 3 O 8 and only 6 plants remained in operation. A new record in production of 7,295 kt of U 3 O 8 was set in 1980. The revival in the industry during the intervening years was accompanied by improvements in all sections of the processing route employed to treat Witwatersrand ores. Ferric leaching, countercurrent decantation, belt filters, hopper clarification, solvent extraction, and continuous ion exchange have all found application in the new or modified plants that have been built. These developments are described, together with the novel process use by Palabora Mining Company for the recovery of uranium from uranothorianite concentrates as a byproduct from copper production

  5. Paving the Road to Success: A Framework for Implementing the Success Tutoring Approach

    Directory of Open Access Journals (Sweden)

    Spark Linda

    2017-12-01

    Full Text Available The exponential growth of higher education enrolment in South Africa has resulted in increased diversity of the student body, leading to a proliferation of factors that affect student performance and success. Various initiatives have been adopted by tertiary institutions to mitigate the negative impact these factors may have on student success, and it is suggested that interventions that include aspects of social integration are the most successful. This paper outlines an approach called Success Tutoring (a non-academic tutorial approach used as part of a student success and support programme in the Faculty of Commerce, Law, and Management at the University of the Witwatersrand, which is underscored by empirical evidence drawn from evaluation data collected during Success Tutor symposia. The authors draw conclusions and make recommendations based on a thematic analysis of the dataset, and ultimately provide readers with a framework for implementing Success Tutoring at their tertiary institutions.

  6. MINTEK: How it all came about

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    A review is given on the history of MINTEK - tracing it back to the discovery of diamonds in South Africa. The Government agreed to co-operate with the University of Witwatersrand and on 23 July 1935 the Minerals Research Laboratory was opened. The work that the Laboratory undertook can be divided into three categories: i) research requested or sponsored by private companies, government departments and institutions, and universities (this includes research on the vermiculite deposits at Phalaborwa); ii) Work of national importance (including work on refractory gold ores); iii) Fundamental work of pure research (including flotation). After the second World War, the USA and Britain made joint effort to discover new sources of uranium supply. Research was also done in South Africa. Act no. 84 of 1981 created the Council for Mineral Technology (MINTEK), which incorporated certain activities of the Atomic Energy Board

  7. Performance of an industrial wet high-intensity magnetic separator for the recovery of gold and uranium

    Energy Technology Data Exchange (ETDEWEB)

    Corrans, I.J.; Liddell, K.S.; Dunne, R.C. (Council for Mineral Technology, Randburg (South Africa). Ore-dressing Div.); Gilbert, W.A. (General Mining Union Corp. Ltd., Johannesburg (South Africa))

    1984-03-01

    After bench-scale and pilot-plant tests in which it was shown that wet high-intensity magnetic separation (WHIMS) can achieve good recoveries of gold and uranium from Witwatersrand residues, a production-size machine was installed at a gold mine. The mechanical and metallurgical performance of this machine have been satisfactory, and the economics of the process are attractive. WHIMS can be combined with other unit operations like flotation for the optimization of overall gold and uranium recoveries. This concept is shown to be relevant, not only to operations for the retreatment of tailings, but to processes for the treatment of coarser material. In the latter, there is a saving in energy consumption compared with the energy required for the fine grinding of the total feed, and a material suitable for underground backfill can be produced. Improved, more cost-effective WHIMS machines currently under development are also described.

  8. Peatlands as Filters for Polluted Mine Water?—A Case Study from an Uranium-Contaminated Karst System in South Africa—Part I: Hydrogeological Setting and U Fluxes

    Directory of Open Access Journals (Sweden)

    Ewald Erasmus

    2011-03-01

    Full Text Available Located downstream of goldfields of the Witwatersrand basin, the Gerhard Minnebron (GMB Eye—as major water source for downstream community of some 300,000 people—may be impacted on by mining-related water pollution especially with uranium (U. Containing up to 5 m-thick deposits of peat that is frequently reported to act as a filter for U and other heavy metals, this paper is the first part of a series that aims to quantify the ability of the GMB peatland to act as buffer against current and future U pollution. In a first step, this paper outlines the geohydrological conditions and discusses how deep–level gold mining impacted on the dolomitic aquifers. Subsequently, the potential influx of U into the wetland is estimated and associated sources and pathways analyzed. Finally, a model is proposed explaining the significant differences in degree and dynamics of U observed within a single groundwater compartment.

  9. A GIS approach to seismic risk assessment with an application to mining-related seismicity in Johannesburg, South Africa

    Science.gov (United States)

    Liebenberg, Keagen; Smit, Ansie; Coetzee, Serena; Kijko, Andrzej

    2017-08-01

    The majority of seismic activity in South Africa is related to extensive mining operations, usually in close proximity to densely populated areas where a relatively weak seismic event could cause damage. Despite a significant decrease in mining operations in the Witwatersrand area, the number of seismic events appears to be increasing and is attributed to the acid mine drainage problem. The increased seismicity is raising concern amongst disaster management centres and in the insurance industry. A better understanding is required of the vulnerability and the size of the potential loss of people and infrastructure in densely populated Johannesburg and its surrounding areas. Results of a deterministic seismic risk, vulnerability, and loss assessment are presented by making use of a geographic information system (GIS). The results illustrate the benefits of using GIS and contribute to a better understanding of the risk, which can assist in improving disaster preparedness.

  10. Neoadjuvant chemotherapy among patients treated for nonmetastatic breast cancer in a population with a high HIV prevalence in Johannesburg, South Africa

    Directory of Open Access Journals (Sweden)

    Ruff P

    2018-02-01

    Full Text Available Paul Ruff,1,2 Herbert Cubasch,2,3 Maureen Joffe,2,4 Evan Rosenbaum,5 Nivashni Murugan,2,3 Ming-Chih Tsai,2,3 Oluwatosin Ayeni,2 Katherine D Crew,5–7 Judith S Jacobson,6,7 Alfred I Neugut5–7 1Division of Medical Oncology, Department of Internal Medicine, University of the Witwatersrand, Faculty of Health Sciences, 2Noncommunicable Diseases Research Division, Wits Health Consortium, University of the Witwatersrand, Faculty of Health Sciences, 3Department of Surgery, Chris Hani Baragwanath Academic Hospital and University of the Witwatersrand, Faculty of Health Sciences, 4MRC Developmental Pathways of Health Research Unit, Department of Paediatrics, University of Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa; 5Department of Medicine, College of Physicians and Surgeons, Columbia University, 6Herbert Irving Comprehensive Cancer Center, Columbia University, 7Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA Background: Neoadjuvant (primary chemotherapy (NACT is the standard of care for locally advanced breast cancer. It also allows for the short-term assessment of chemotherapy response; a pathological complete responses correspond to improved long-term breast cancer outcomes. In sub-Saharan Africa, many patients are diagnosed with large nonresectable tumors. We examined NACT use in breast cancer patients who visited public hospitals in Johannesburg, South Africa. Methods: We assessed demographic characteristics, tumor stage and grade, hormone receptor status, and human immunodeficiency virus (HIV status of female patients diagnosed with nonmetastatic invasive carcinoma of the breast at Chris Hani Baragwanath Academic Hospital between January 1, 2009, and December 31, 2011. The patients received neoadjuvant, adjuvant, or no chemotherapy. Trastuzumab was unavailable. We developed logistic regression models to analyze the factors associated with NACT receipt in these patients

  11. International uranium production. A South African perspective

    International Nuclear Information System (INIS)

    Sinclair-Smith, D.

    1984-01-01

    Between 1981 and 1983 South Africa experienced a decline in its uranium resources of 23% in the less than $80/kg U category and 12% in the less than $130/kg U category. In 1983 only $5 million was spent on exploration, with activities being concentrated in the Witwatersrand Basin as a byproduct of gold exploration. South Africa has maintained a production level of around 6000 mt U in 1981, 1982 and 1983. One unusual feature of the South African uranium scene is the ability to selectively dump relatively high grade uranium tailings after the extraction of gold and to rework this material as well as material dumped prior to the emergence of the uranium industry. Uranium from this source amounted to some 28% of total production in 1983. (L.L.) (2 tabs., 6 figs.)

  12. The gold analyser: a tool for valuation and a means for improved mining decisions

    International Nuclear Information System (INIS)

    Stewart, J.M.; Nami, M.

    1986-01-01

    The erratic values of gold grade in Witwatersrand placer deposits necessitates the collection of large numbers of samples for accurate valuation and ore reserve estimation. Owing to manpower requirements current sampling techniques do not allow for the collection of sufficiently large numbers of samples. A portable gold analyser, which is at an advanced stage of development, is expected to alleviate this problem. It is a lightweight instrument, intended for one-man operation, and is based on energy dispersive X-ray fluorescence principles for determining gold and other mineral concentrations. The instrument is designed for in situ face scanning operations and provides a direct readout and internal storage of the measured gold concentration. The immediate availability of an estimate of gold grade should significantly improve the quality of short-term panel-scale mining decisions. Data are presented to show the improved precision in valuation using the gold analyser instead of conventional chip sampling

  13. South African gold and uranium ore mining in 1976

    International Nuclear Information System (INIS)

    Hentrich, W.

    1977-01-01

    1976 was a difficult year for the South African gold and uranium ore mining industry, the region of Witwatersrand (Transvaal province) producing some 75% of all the gold mined in the western world besides being an important producer of uranium oxide. Despite the gold production, declining since 1971, not showing a downward tendency anymore as far as the quantity was concerned, the economic result, however, deteriorated as a consequence of continuously falling gold prices, but also on account of the inflationary rise in wages and the prices for energy and materials. Much higher prices for uranium oxide, which some mines produce as interim products from the 'degolded' slurries of their gold ore leaching plants, improved the economic overall result only to a small degree. (orig.) [de

  14. Geochemistry and morphology of mineral components from the fossil gold and uranium placers of the Witwatersand

    International Nuclear Information System (INIS)

    Hallbauer, D.K.

    1981-01-01

    Using the hydrofluoric-acid leaching technique to obtain heavy-mineral grains intact from Witwatersrand conglomerates and the scanning electron microscope with microanalyzer attachment, the technique of morphological microscopy was applied to observe the three dimensions of the grains and to study their composition. In combination with stereo x-ray radiography of rock slabs and the application of various geochemical techniques, this afforded new information on the processes that led to the formation of Precambrian placer deposits. Fossilized organisms could consequently be recognized from the morphology of their carbonaceous remains, permitting their role in the concentration of gold and uranium to be explained. Studies of the morphology of different types of gold, pyrite, and other minerals have permitted conclusions on the origin and distribution of economically important minerals, as well as on the palaeoenvironment of Precambrian placers that were not possible with the classical methods of microscopy

  15. Uranium deposits in Proterozoic quartz-pebble conglomerates

    International Nuclear Information System (INIS)

    1987-09-01

    This report is the result of an effort to gather together the most important information on uranium deposits in Proterozoic quartz-pebble conglomerates in the United States of America, Canada, Finland, Ghana, South Africa and Australia. The paper discusses the uranium potential (and in some cases also the gold potential in South Africa, Western Australia and Ghana) in terms of ores, sedimentation, mineralization, metamorphism, placers, geologic formations, stratigraphy, petrology, exploration, tectonics and distribution. Geologic history and application of geologic models are also discussed. Glacial outwash and water influx is also mentioned. The uranium deposits in a number of States in the USA are covered. The Witwatersrand placers are discussed in several papers. Refs, figs, tabs

  16. Energy budgets of mining-induced earthquakes and their interactions with nearby stopes

    Science.gov (United States)

    McGarr, A.

    2000-01-01

    In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more than sufficient to account for the mining-induced earthquakes. I report here updated versions of these two results based on more modern underground data acquired in the Witwatersrand gold fields. Firstly, an extensive suite of in situ stress data indicate that the ambient state of crustal stress here is close to the failure state in the absence of mining even though the tectonic setting is thoroughly stable. Mining initially stabilizes the rock mass by reducing the pore fluid pressure from its initial hydrostatic state to nearly zero. The extensive mine excavations, as Cook showed, concentrate the deviatoric stresses, in localized regions of the abutments, back into a failure state resulting in seismicity. Secondly, there appears to be two distinct types of mining-induced earthquakes: the first is strongly coupled to the mining and involves shear failure plus a coseismic volume reduction; the second type is not evidently coupled to any particular mine face, shows purely deviatoric failure, and is presumably caused by more regional changes in the state of stress due to mining. Thirdly, energy budgets for mining induced earthquakes of both types indicate that, of the available released energy, only a few per cent is radiated by the seismic waves with the majority being consumed in overcoming fault friction. Published by Elsevier Science Ltd.In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more than sufficient to account for the

  17. U-Pb and Pb-Pb study of the Murchison Greenstone Belt and of the Evander gold-bearing basin, South Africa. Implications for the evolution of the Kaapvaal craton

    International Nuclear Information System (INIS)

    Poujol, M.

    1997-01-01

    This study presents new U-Pb and Pb-Pb isotopic data for both the Central Rand Group from the Evander Goldfield and the Murchison Greenstone Belt (Republic of South Africa). The Evander Goldfield, where no previous isotopic data have been derived, is located in the eastern side of the Witwatersrand basin. The oldest age measured is ca. 3180 Ma, while the majority of detritus falls in the range 3050-2850 Ma. New growth of zircon (or isotopic resetting of older detritus) appears to have been associated with deposition of the Ventersdorp lavas at ca. 2.7 Ga. A small proportion of the pyrite, mainly extracted from unaltered sediments in the Kimberley Reef footwall, yields ages that are in excess of the minimum depositional age of the Witwatersrand Basin. Authigenic pyrite, as well as detrital grains from highly altered portions of the Kimberley Reef, define two main events. The Pb signature of the 2370 Ma event is probably associated with burial of the basin by the upper portion of the Transvaal sequence, and suggests circulation of highly radiogenic fluids. Isotopic signatures for the 2020 Ma event are probably related to Bushveld intrusion and/or Vredefort catastrophism, and appear to be associate with a fluid that was less radiogenic. The present study shows a number of new results which support a complex, multi-stage evolution and genesis of the Au-U deposits within the Witwatersrand Basin. The Murchison Greenstone Belt constitutes one of the world's largest antimony producing areas and also hosts gold, as well as volcanogenic massive sulfide Cu-Zn mineralization and emeralds. The goal of this study is to determine the age of the belt as well as the timing of mineralization and, also, to assess the potential role of granitoids in the ore-forming processes. The data identify an episode of greenstone formation between 3.09 Ga and 2.97 Ga. Three main magmatic events are identified at ca. 2.97, 2.82 and 2.68 Ga. Pyrites associated with both Sb-Au and Cu

  18. Human resources for research: building bridges through the Diaspora.

    Science.gov (United States)

    Hofman, Karen; Kramer, Beverley

    2015-01-01

    The collaboration of scientists between the developed and the developing world is an opportunity to reverse the 'brain drain' and to enable 'brain circulation'. Attracting alumni from the Diaspora to strengthen the development of talented scientists will strengthen research in Africa. In 2010, the Faculty of Health Sciences at the University of the Witwatersrand, South Africa (SA), created an Alumni Diaspora Programme to boost international research collaboration and networking between leading medical and health sciences alumni who now live and work at academic institutions abroad with academic colleagues 'back home'. Based in Johannesburg, a gateway city attracting researchers from all over sub-Saharan Africa, this programme has the potential to capitalise on some of the intellectual capacity that was lost, mostly during the decades of apartheid, and to strengthen capacity, not just in SA, but across the continent. The goal of this review is to highlight how this programme has stimulated collaborations and networking with international alumni.

  19. Exploitation of the vulnerable in research: Responses to lessons learnt in history.

    Science.gov (United States)

    Dhai, Amaboo

    2017-05-24

    The Nuremberg Trials raised insightful issues on how and why doctors who were trained in the Hippocratic tradition were able to commit such egregious and heinous medical crimes. The vulnerable were considered to be subhuman, of decreased intelligence, of no moral status and lacking human dignity. The reputation of the medical profession had been undermined, professionalism questioned and the doctor-patient relationship damaged as a result of the Nazi medical experiments. The World Medical Association's Declaration of Helsinki has been hailed as one of the most successful efforts in rescuing medical research from the darkness of the scandals and tragedies in health research. The first Research Ethics Committee in South Africa was established in 1966 at the University of the Witwatersrand. From the mid-1970s other institutions followed suit. The promulgation of the National Health Act No. 61 of 2003, in 2004, resulted in strong protectionism for research participants in the country.

  20. Research in Nickel/Metal Hydride Batteries 2017

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2018-02-01

    Full Text Available Continuing from a special issue in Batteries in 2016, nineteen new papers focusing on recent research activities in the field of nickel/metal hydride (Ni/MH batteries have been selected for the 2017 Special Issue of Ni/MH Batteries. These papers summarize the international joint-efforts in Ni/MH battery research from BASF, Wayne State University, Michigan State University, FDK Corp. (Japan, Institute for Energy Technology (Norway, Central South University (China, University of Science and Technology Beijing (China, Zhengzhou University of Light Industry (China, Inner Mongolia University of Science and Technology (China, Shenzhen Highpower (China, and University of the Witwatersrand (South Africa from 2016–2017 through reviews of AB2 metal hydride alloys, Chinese and EU Patent Applications, as well as descriptions of research results in metal hydride alloys, nickel hydroxide, electrolyte, and new cell type, comparison work, and projections of future works.

  1. Recent developments of high quality synthetic diamond single crystals for synchrotron X-ray monochromators

    CERN Document Server

    Freund, A K; Sellschop, J P Friedel; Burns, R C; Rebak, M

    2001-01-01

    For several years now, the ESRF, the University of the Witwatersrand and Messrs. De Beers Industrial Diamonds (Pty) Ltd. through their Diamond Research Laboratory, have pursued a development programme to assess and improve the quality of synthetic diamonds. Recently, in an effort to study the influence of nitrogen impurities on the defect structure, X-ray excited optical luminescence and spatially resolved double-crystal diffractometry were employed as new techniques. The correlation between nitrogen impurities and the raw defect structure was clearly visible. It was confirmed that concentration variations are related to lattice imperfections, where tilts are much more important than lattice constant variations. High reflectivity was observed and quite large zones of a sample bigger than 1 cm sup 2 showed to be perfect to within better than 0.5 arcsec.

  2. The sex profile of skeletal remains from a cemetery of Chinese indentured labourers in South Africa

    Directory of Open Access Journals (Sweden)

    Paul Ruff

    2010-07-01

    Full Text Available For a short period of time in the early 20th century, indentured labourers from China were imported to work on the South African gold mines. The Raymond A. Dart Collection of Human Skeletons contains 36 skeletons sourced from a Chinese cemetery of this time period on the site of the old Witwatersrand Deep Gold Mine. An earlier morphometric study on this collection recorded a high number of female individuals. However, the general historical records from the early gold mining era conflict with the results of this study, stating that very few Chinese females were among those to arrive in South Africa. In this study, the sex profile of this collection was analysed using molecular sex identification through the amelogenin gene. Results were obtained for 13 (41.93% specimens, all of which were determined to be male – data that correspond well with the historical records.

  3. Ore-processing technology and the uranium supply outlook

    International Nuclear Information System (INIS)

    James, H.E.; Simonsen, H.A.

    1978-01-01

    The subject is covered in sections, as follows: the resource base (uranium content of rocks, regional distribution of Western World uranium); ore types (distribution of Western World uranium, by ore types, response to ore-processing); constraints on expansion in traditional uranium areas (defined for this paper as the sandstone deposits of the U.S.A. and the quartz-pebble conglomerates of the Witwatersrand and Elliot Bay areas, all other deposits being referred to as new uranium areas). Sections then follow dealing in detail with the processing of deposits in U.S.A., South Africa, Canada, Niger, Australia, South West Africa, Greenland. More general sections follow on: shale, lignite and coal deposits, calcrete deposits. Finally, there are sections on: uranium as a by-product; uranium from very low-grade resources; constraints on expansion rate for production facilities. (U.K.)

  4. The auriferous placer at Mount Robert, Pietersburg Greenstone belt

    International Nuclear Information System (INIS)

    Saager, R.; Muff, R.

    1986-01-01

    The Mount Robert gold placer near Potgietersrus occurs in coarse, matrix-supported conglomerates of the Uitkyk Formation within the Pietersburg greenstone belt. Sedimentological and mineralogical investigations indicate that the conglomerates and the ore minerals were derived from a greenstone provenance, and that they were deposited in a braided river environment within a rapidly subsiding trough. Lack of sedimentological concentration of the heavy minerals is considered to be the main reason for the low and erratic gold grades encountered (usually below 1 g/t) and, thus, the failure of all past mining ventures. The mineralogical composition of the Mount Robert ore closely resembles that of the Witwatersrand deposits. However, uraninite is absent, probably as a result of its complete removal by weathering processes. Remaining small uranium concentrations can still be detected within the conglomerates where they occur associated with grains of carbonaceous matter, leucoxene aggregates, and secondary iron-hydroxides. U3O8 values found in the conglomerates are given

  5. Exploitation of the vulnerable in research: Responses to lessons learnt in history

    Directory of Open Access Journals (Sweden)

    Amaboo Dhai

    2017-06-01

    Full Text Available The Nuremberg Trials raised insightful issues on how and why doctors who were trained in the Hippocratic tradition were able to commit such egregious and heinous medical crimes. The vulnerable were considered to be subhuman, of decreased intelligence, of no moral status and lacking human dignity. The reputation of the medical profession had been undermined, professionalism questioned and the doctor-patient relationship damaged as a result of the Nazi medical experiments. The World Medical Association’s Declaration of Helsinki has been hailed as one of the most successful efforts in rescuing medical research from the darkness of the scandals and tragedies in health research. The first Research Ethics Committee in South Africa was established in 1966 at the University of the Witwatersrand. From the mid-1970s other institutions followed suit. The promulgation of the National Health Act No. 61 of 2003, in 2004, resulted in strong protectionism for research participants in the country.

  6. Distribution and sedimentary arrangement of carbon in South African proterozoic placer deposits

    International Nuclear Information System (INIS)

    Minter, W.E.L.

    1981-01-01

    Carbon, which occurs as grains, films, and thin seams in Witwatersrand Proterozoic placer deposits, is generally confined to carbon-seam reefs that were deposited in distal environments. The distribution of carbon on paleosurfaces, on sedimentary accumulation surfaces like pebble layers, on trough-shaped bedforms of pi-crossbedded units and foresets, and on the winnowed top of placer sediments implies that its growth took place contemporaneously with placer deposition in an aquatic fluvial environment. The areal distribution of carbon seams in distal environments is patchy, and its sparsity or total absence in some areas does not affect either the gold or the uranium content of the placer. High gold and uranium contents that appear to be associated with carbon seams are at the base of the reef because that position represents both the stable consolidated paleosurface upon which the plant material anchored itself and also the surface of bedload concentration

  7. South African uranium resources - 1997 assessment methodology and results

    International Nuclear Information System (INIS)

    Ainslie, L.C.

    2001-01-01

    The first commercial uranium production in South Africa started in 1953 to meet the demand for British/US nuclear weapons. This early production reached its peak in 1959 and began to decline with the reduced demand. The world oil crisis in the 1970s sparked a second resurgence of increased uranium production that peaked in 1980 to over 6,000 tonnes. Poor market condition allied with increasing political isolation resulted in uranium production declining to less than a third of the levels achieved in the early 1980s. South Africa is well endowed with uranium resource. Its uranium resources in the RAR and EAR-I categories, extractable at costs of less than $80/kg U, as of 1 January 1997, are estimated to 284 400 tonnes U. Nearly two thirds of these resources are associated with the gold deposits in the Witwatersrand conglomerates. Most of the remaining resources occur in the Karoo sandstone and coal deposits. (author)

  8. Uranium in South Africa: 1985

    International Nuclear Information System (INIS)

    1986-03-01

    South Africa's participation in the nuclear industry was limited to the production of uranium and research, with minor commercial activities. The commissioning of the Koeberg Nuclear power station in 1984 placed South Africa firmly on the path of commercial nuclear power generation. A unique, locally developed uranium enrichment process will enable South Africa to be self-sufficient in its nuclear-fuel needs. Uranium has always been of secondary importance to gold as a target commodity in the exploration of the quartz-pebble conglomerates. In the Witwatersrand Basin it is estimated that in excess of R100 million was spent on exploration during 1985. This was spent primarily in the search for gold but as many of the gold reefs are uraniferous, new uranium resources are being discovered concurrently with those of gold. Uranium mineralization is present in rocks which encompass almost the whole of the geological history of South Africa. Significant mineralization is restricted to five fairly well-defined time periods. Each period is characterized by a distinct type or combination of types of mineralization. Resource estimates are divided into separate categories that reflect different levels of confidence in the quantities reported. The resource categories are further separated into levels of exploitability based on the estimated cost of their exploitation. A major part (87%) of South Africa's uranium resources is present as a by-product of gold in the quartz-pebble conglomerates of the Witwatersrand Basin. The uranium resources in the reasonably assured resources (RAR) and estimated additional resources - category I (EAR-I) catogories were 483 300 t U. Production during 1985 was 4880 t U. Although a production peaking at over 1200 t U/a is theoretically attainable, it is considered, from market projections, that a production ceilling of 10 000 t U/a would be more realistic

  9. Uranium in South Africa: 1987

    International Nuclear Information System (INIS)

    1988-06-01

    South Africa's participation in the nuclear industry was limited to the production of uranium and research, with minor commercial activities. The commissioning of the Koeberg Nuclear power station in 1984 placed South Africa firmly on the path of commercial nuclear power generation. A unique locally developed uranium enrichment process wil enable South Africa to be self-sufficient in its nuclear-fuel needs. Uranium has always been of secondary importance to gold as a target commodity in the exploration of the quartz-pebble conglomerates. In the Witwatersrand Basin it is estimated that in excess of R300 million was spend on exploration during 1987. This was spend primarily in the search for gold but as many of the gold reefs are uraniferous, new uranium resources are being discovered concurrently with those of gold. Uranium mineralization is present in rocks which encompass almost the whole of the geological history of South Africa. Significant mineralization is restricted to five fairly well-defined time periods. Each period is characterized by a distinct type or combination of types of mineralization. Resource estimates are divided into separate categories that reflect different levels of confidence in the quantities reported. The resource categories are further separated into levels of exploitability based on the estimated cost of their exploitation. A major part (87%) of South Africa's uranium resources is present as a by-product of gold in the quartz-pebble conglomerates of the Witwatersrand Basin. The uranium resources in the RAR and EAR-I categories were 536 500 t u. Production during 1987 was 3963 t u. Although a production peaking at over 1100 t U/a is theoretically attainable, it is considered, from market projections, that a production ceiling of 10 000 t U/a would be more realistic

  10. Urbanization in Africa since independence.

    Science.gov (United States)

    Tarver, J D

    1994-01-01

    Over 185 million inhabitants were added to the urban areas of Africa between 1950 and 1990. Botswana, Lesotho, Namibia, South Africa, and Swaziland is the most highly urbanized, with 55% in 1990; while less than a quarter of Eastern Africa's population is living in urban centers. By the year 2015 more than half of Africa's population will be living in urban areas. Many parts of Africa have suffered prolonged droughts, overgrazing, locust infestations, and desertification. Millions have become refugees from natural disasters, political oppression, and rural poverty. The large exodus from Africa's rural areas has gone to cities but the large cities have attracted disproportionately large numbers of destitute migrants. Alexandria (1 million), Cairo (2.4 million) and the Witwatersrand in South Africa were the only African urban agglomerations with at least one million inhabitants in 1950. By 1990 the two Egyptian cities together had 12.7 million inhabitants and the Witwatersrand some 5 million, whereas the other 25 urban agglomerations with a million inhabitants each in 1990 had a total population of about 51 million. Lagos, Kinshasa, and Algiers ranged from 3 to 7.7 million. The capitals are the largest cities in at least 54 of the 59 countries and territories. Lagos, Nairobi, and Dar es Salaam are disproportionately larger than the next most populous cities in their countries. The 28 urban agglomerations with at least one million inhabitants had a total population of 70 million in 1990, and are projected to reach 100 million in the year 2000. Overall, Africa's urban population is projected to increase by approximately 135 million in the 1990-2000 decade (from 217 million to 352 million). About 105 million of the growth probably will occur in the smaller urban centers. The total African urban population is likely to reach one billion inhabitants within the next 50 years. It stood at 32 million in 1950. Presently, the United Nations projects 912 million urban residents

  11. A study of the isotopic and geochemical gradients in the old granite of the Vredefort structure, with implications for continental heat flow

    International Nuclear Information System (INIS)

    Hart, R.J.

    1978-01-01

    The presence of granite of pre-Witwatersrand age forming the core of an updomed and overturned sequence of strata at Vredefort, South Africa, has been known for over seventy years. It is only recent geophysical, geochemical and geological evidence that has given rise to the proposal that the basement core has also been overturned, presenting a section of the earth's granitic crust to view. Comprehensive geochemical and isotope studies on this section are presented in the thesis. Detailed trace element profiles across the granite basement inidicate that (i) the central part of the core is depleted in the large ion lithophile elements U, Th and Rb, relative to the perimeter, (ii) the concentrations of U, Th and Rb falls of regularly from the granite margin inwards, and the distribution of these elements over the outer 8 km is consistent with an exponential depth-function, and (iii) the central part of the core is characterised by high K/Rb, Th/U, K/U, K/Th, Ba/Rb and low Rb/Sr ratios, and it is only the outer 5 km of the basement core that has elemental ratios which approach those found in 'normal' surface granites. The heat generation from the entire exposed vertical section of the Vredefort granite, together with heat production in the overlying stratified rocks, has been examined. By comparing the heat production in the crust to heat flow in the nearby Far West Witwatersrand goldfield, a reasonable estimate of the heat flow from the mantle has been made. A value of between .25 and .36 HFU has been estimated. The mantle heat flow has an important bearing on the depth of the lithosphere - asthenosphere boundary. Whole rock Rb-Sr, Th-Pb isotopic investigations were made on the granite and basic rocks of the Vredefort basement. The measured ages and initial ratios provide evidence that well preserved remnants of sedimentary supracrustals and basic to intermediate volcanics existed as a protocrust in pre-3.5 b.y. times

  12. Atmospheric Chemistry Over Southern Africa

    Science.gov (United States)

    Gatebe, Charles K.; Levy, Robert C.; Thompson, Anne M.

    2011-01-01

    During the southern African dry season, regional haze from mixed industrial pollution, biomass burning aerosol and gases from domestic and grassland fires, and biogenic sources from plants and soils is worsened by a semi-permanent atmosphere gyre over the subcontinent. These factors were a driver of several major international field campaigns in the 1990s and early 2000s, and attracted many scientists to the region. Some researchers were interested in understanding fundamental processes governing chemistry of the atmosphere and interaction with climate change. Others found favorable conditions for evaluating satellite-derived measurements of atmospheric properties and a changing land surface. With that background in mind a workshop on atmospheric chemistry was held in South Africa. Sponsored by the International Commission for Atmospheric Chemistry and Global Pollution (ICACGP; http://www.icacgp.org/), the workshop received generous support from the South African power utility, Eskom, and the Climatology Research Group of the University of the Witwatersrand, Johannesburg, South Africa. The purpose of the workshop was to review some earlier findings as well as more recent findings on southern African climate vulnerability, chemical changes due to urbanization, land-use modification, and how these factors interact. Originally proposed by John Burrows, president of ICACGP, the workshop was the first ICACGP regional workshop to study the interaction of air pollution with global chemical and climate change. Organized locally by the University of the Witwatersrand, the workshop attracted more than 60 delegates from South Africa, Mozambique, Botswana, Zimbabwe, France, Germany, Canada, and the United States. More than 30 presentations were given, exploring both retrospective and prospective aspects of the science. In several talks, attention was focused on southern African chemistry, atmospheric pollution monitoring, and climate processes as they were studied in the field

  13. Quartz-pebble-conglomerate gold deposits: Chapter P in Mineral deposit models for resource assessment

    Science.gov (United States)

    Taylor, Ryan D.; Anderson, Eric D.

    2018-05-17

    Quartz-pebble-conglomerate gold deposits represent the largest repository of gold on Earth, largely due to the deposits of the Witwatersrand Basin, which account for nearly 40 percent of the total gold produced throughout Earth’s history. This deposit type has had a controversial history in regards to genetic models. However, most researchers conclude that they are paleoplacer deposits that have been modified by metamorphism and hydrothermal fluid flow subsequent to initial sedimentation.The deposits are found exclusively within fault-bounded depositional basins. The periphery of these basins commonly consists of granite-greenstone terranes, classic hosts for lode gold that source the detrital material infilling the basin. The gold reefs are typically located along unconformities or, less commonly, at the top of sedimentary beds. Large quartz pebbles and heavy-mineral concentrates are found associated with the gold. Deposits that formed prior to the Great Oxidation Event (circa 2.4 giga-annum [Ga]) contain pyrite, whereas younger deposits contain iron oxides. Uranium minerals and hydrocarbons are also notable features of some deposits.Much of the gold in these types of deposits forms crystalline features that are the product of local remobilization. However, some gold grains preserve textures that are undoubtedly of detrital origin. Other heavy minerals, such as pyrite, contain growth banding that is truncated along broken margins, which indicates that they were transported into place as opposed to forming by in situ growth in a hydrothermal setting.The ore tailings associated with these deposits commonly contain uranium-rich minerals and sulfides. Oxidation of the sulfides releases sulfuric acid and mobilizes various metals into the environment. The neutralizing potential of the tailings is minimal, since carbonate minerals are rare. The continuity of the tabular ore bodies, such as those of the Witwatersrand Basin, has allowed these mines to be the deepest in

  14. Interdisciplinary Environmental Summer Study Abroad in Southern Africa as a Mechanism for the Development of an International Research and Education Consortium

    Science.gov (United States)

    Swap, R. J.; Sabea, H.; Annegarn, H.; Ford, C.; Netshandama-Funyufunyu, V.; Omara-Ojungu, P.; Vaz, K.; Ribeiro, N.; Twine, W.; Terni, C.; Estes, L.

    2005-12-01

    We describe an interdisciplinary course for non-specialist undergraduates in which the students experience firsthand issues of regional environmental complexity and have the unique opportunity to gain insight into the role the environment plays in shaping the people and culture of southern Africa. Undergraduates receive 3 hours of credit both in Environmental Science and Anthropology for the ``People, Culture and Environment of Southern Africa" study abroad program. The program is an intensive introduction to the physical geography, history and culture of the region and involves an intensive blend of in-class lectures and field trips with daily debriefing discussions. Over the duration of the 30 day program, students are exposed to elements of geology, ecology, hydrology and atmospheric science and how the interconnectedness of these different aspects of the physical environment help shape the history of the people and their culture in the region. Information about logistics and course development as well as to how this summer study abroad program has contributed to the development and expansion of the Southern Africa Virginia Networks and Associations (SAVANA) consortium will be detailed. The program builds upon more than 12 years of relationships between UVA faculty and their southern African colleagues developed during the course of several regional scale research programs with the most recent being the Southern African Regional Science Initiative - SAFARI 2000. Students enrolled with the UVA program are joined by their counterparts and interact with faculty from institutional partners both in the classroom and in the field. Participants operate out of four major locations: Johannesburg, RSA (Univ. of the Witwatersrand); Thohoyondou, RSA (Univ. of Venda); Maputo, MOZ (Univ. of Eduardo Mondlane); and Acornhoek, RSA (Univ. of the Witwatersrand - Rural Facility). Class size is limited to 15 students from UVA and about 6 SAVANA consortium students. This pairing with

  15. ‘I got content with who I was’: Rural teachers’ encounters with new ways of practising literacy

    Directory of Open Access Journals (Sweden)

    Toni Gennrich

    2016-07-01

    Full Text Available In a context where Foundation Phase literacy teachers’ personal literacy often involves operational and technicist practices rather than creative, this paper argues that it is by exposing teachers to experiences of working with different genres of text for an extended time, in different fields, that teachers are able to imagine the possibilities these genres afford. Using a Bourdieusian framework of habitus, field, capital and doxa and applying imagination to the theorisation of these concepts, I examine the effect on a group of rural teachers from Limpopo province of being removed from their classrooms, and being given the opportunity to complete a 4-year Bachelor of Education degree at the University of the Witwatersrand. This case study used reflective journals and focus groups to trace shifts in the ways these teacher-students enacted literacy and thought about teaching literacy. Findings from this study suggest that teachers of literacy can change deeply entrenched ways of thinking about and valuing literacy by reflecting on the discontinuities between old and new ways of practice and, through anticipatory reflection, to imagine possibilities of teaching and enacting literacy differently. This requires critical imagination, awareness and agency. This paper discusses, in particular, Elela’s experience with poetry and Kganya’s experience with a drama script, assessing the effect this had on their personal literacy practices and how they imagine teaching literacy in the future.

  16. Henry Selby Hele-Shaw LLD, DSc, EngD, FRS, WhSch (1854-1941: Engineer, inventor and educationist

    Directory of Open Access Journals (Sweden)

    Jane Carruthers

    2010-03-01

    Full Text Available H.S. Hele-Shaw (1854–1941 was one of the most outstanding engineering scientists of his generation and an eminent figure in engineering education during the late-19th and early-20th centuries. His work in hydrodynamics (the Hele-Shaw cell and Hele-Shaw pump and his important contribution to the successful development of high-speed aircraft (his variable pitch airscrew, continues to be relevant today. In 1922, as President of the Institution of Mechanical Engineers, he introduced the National Certificate scheme in Britain. It is not well known that Hele-Shaw spent two years in South Africa (1904–1905 attached to the Transvaal Technical Institute, a forerunner of the University of the Witwatersrand. One of only three Fellows of the Royal Society of London in southern Africa in 1905, he was a founder Council member of the Royal Society of South Africa and one of the hosts of the 1905 visit to southern Africa by the British Association for the Advancement of Science. The purpose of this paper is to highlight the time he spent in South Africa and to contextualise it within the larger perspective of his engineering career.

  17. Three-dimensional technology for linear morphological studies: a re-examination of cranial variation in four southern African indigenous populations.

    Science.gov (United States)

    Franklin, D; Freedman, L; Milne, N

    2005-01-01

    In order to compare linear dimensions made by traditional anthropometric techniques, and those obtained from three-dimensional coordinates, samples of four indigenous southern African populations were analysed. Linear measurements were obtained using mathematically transformed, three-dimensional landmark data on 207 male crania of Cape Nguni, Natal Nguni, Sotho and Shangaan. Univariate comparisons for accuracy of the transformed linear data were made with those in a traditional linear study by de Villiers (The Skull of the South African Negro: A Biometrical and Morphological Study. Witwatersrand University Press, Johannesburg) on similar samples and equivalent landmarks. Comparisons were not made with her Penrose (Ann Eugenics 18 (1954) 337) analysis as an apparently anomalous 'shape'-'size' statistic was found. The univariate comparisons demonstrated that accurate linear measurements could be derived from three-dimensional data, showing that it is possible to simultaneously obtain data for three-dimensional geometric 'shape' and linear interlandmark analyses. Using Penrose and canonical variates analyses of the transformed three-dimensional interlandmark measurements, similar population distances were found for the four indigenous southern African populations. The inter-population distance relationships took the form of three separated pairs of distances, with the within-pair distances very similar in size. The cranial features of the four populations were found to be overall very similar morphometrically. However the populations were each shown by CVA to have population specific features, and using discriminant analyses 50% or more of the individual crania (with the exception of the Sotho) could be referred to their correct populations.

  18. Whither α-FP in the diagnosis of hepatocellular carcinoma?

    Directory of Open Access Journals (Sweden)

    Kew MC

    2015-08-01

    Full Text Available Michael C Kew1,2 1Department of Medicine, Groote Schuur Hospital, University of Cape Town, Cape Town, 2University of the Witwatersrand, Johannesburg, South Africaα-FP is an α1-globulin present in high concentration in the fetal serum of mammals. It is the dominant plasma protein in the developing embryo, and is synthesized by the embryonal liver, by the endodermal cells of the visceral yolk sac, and, in very small amounts, by the embryonal intestine.1 Approximately 80% of fetal hepatocytes synthesize and secrete α-FP. The protein has been closely conserved throughout phylogenesis, suggesting that it has functions essential to the fetus, although precisely what these functions are remains to be learned. There does, however, appear to be an inverse relationship between serum α-FP and albumin levels, suggesting that α-FP might function as fetal albumin.2 Other possible biological properties of the α1-globulin include binding to estrogens and bilirubin, immunosuppressive activity, and a growth-promoting potential.3 The serum level of the protein remains constant until week 32, when it begins to sharply decrease. After birth, production of α-FP normally remains completely repressed, and serum concentrations are correspondingly very low.

  19. Sex work, reform initiatives and HIV/AIDS in inner-city Johannesburg.

    Science.gov (United States)

    Richter, Marlise

    2008-11-01

    The on-going criminalisation of sex work in South Africa, concurrent sexual partnerships, socio-economic vulnerability, migrant status and gender-based violence intensify sex workers' risk of contracting HIV. These factors combine to restrict the skills, ability and resources of sex workers to negotiate safer sex and to access HIV prevention, treatment and healthcare services. The paper situates the living and working conditions of sex workers in Hillbrow, an inner-city area of Johannesburg, within the South African legal context, especially in regard to current law reform initiatives regarding sex work, as well as the increasing anxiety about the influx of (sex) tourists during the 2010 FIFA World Cup. In addition, the paper describes an intervention by the Reproductive Health & HIV Research Unit at the University of the Witwatersrand, Johannesburg, an innovator in providing mobile healthcare services and education to hotel-based sex workers in Hillbrow. The paper contends that a legal-rights-approach to HIV risk and vulnerability, together with powerful public health considerations, render decriminalisation an imperative response to sex workers' material conditions.

  20. The role of waste sorting in the South African gold-mining industry

    International Nuclear Information System (INIS)

    Freer, J.S.; Boehme, R.C.

    1985-01-01

    The absolute potential for sorting waste from run-of-mine Witwatersrand gold ores normally lies between 60 and 90 per cent by mass. At present, the practical potential lies between 40 and 50 per cent. Yet few mines achieve a waste rejection of even 30 per cent. The average waste rejection for industry, including underground sorting, fell from 19,6 per cent in 1959 to 10,1 per cent in 1983, as industry moved from labour-intensive, multistage comminution, incorporating washing, screening, and sorting, to single-stage run-of-mine milling. Most of the sorting is still being done by hand; yet photometric and radiometric sorting machines of high capacity are available. More recently, a sorter based on neutron activation and the subsequent isomeric radioactive decay of gold itself was designed. This paper examines the case for an increased role for sorting in the South African gold-mining industry brought about by the increasing cost of power for milling and the possibility of extracting gold from low-grade reject fractions by heap leaching

  1. Sustainable urban development of metropolitan Johannesburg: The lessons learned from international practice

    Directory of Open Access Journals (Sweden)

    Mosha A.C.

    2004-01-01

    Full Text Available This paper consists of an overview of programmes supporting sustainable planning and management in the City of Johannesburg one of the most important social and economic hubs of the transitional Republic of South Africa. Following from this is an analysis of the experience identified as most appropriate for Johannesburg City and its metropolitan region (Gauteng. This case study is used to highlight efforts and lessons learned from the international project "Designing, Implementing and Measuring Sustainable Urban Development" (DIMSUD which have intended to contribute to new solutions for sustainable urban development through a collaborative multi-disciplinary, and participatory approach combining research, urban design, and capacity building. DIMSUD (http://sustainability.ethz.ch is carried out jointly by the Swiss Federal Institute of Technology (ETH Massachusetts Institute of Technology (MIT, Chalmers University of Technology (Sweden, University of Botswana, University of the Witwatersrand (South Africa and the Catholic University of Santiago de Chile. Another partner was the United Nations University (UNU at Tokyo. The project has enabled a global overview of core problems, providing a synthesis of realizable strategies and offering both a scientific forum and an "urban field laboratory" for joint learning. The strategies developed will not only help improve the conditions in the case study cities (Gaborone Johannesburg, Santiago de Chile, but will also provide working examples so that other cities can learn from and adapt and adopt appropriate "best practices".

  2. Automated image processing method for the diagnosis and classification of malaria on thin blood smears.

    Science.gov (United States)

    Ross, Nicholas E; Pritchard, Charles J; Rubin, David M; Dusé, Adriano G

    2006-05-01

    Malaria is a serious global health problem, and rapid, accurate diagnosis is required to control the disease. An image processing algorithm to automate the diagnosis of malaria on thin blood smears is developed. The image classification system is designed to positively identify malaria parasites present in thin blood smears, and differentiate the species of malaria. Images are acquired using a charge-coupled device camera connected to a light microscope. Morphological and novel threshold selection techniques are used to identify erythrocytes (red blood cells) and possible parasites present on microscopic slides. Image features based on colour, texture and the geometry of the cells and parasites are generated, as well as features that make use of a priori knowledge of the classification problem and mimic features used by human technicians. A two-stage tree classifier using backpropogation feedforward neural networks distinguishes between true and false positives, and then diagnoses the species (Plasmodium falciparum, P. vivax, P. ovale or P. malariae) of the infection. Malaria samples obtained from the Department of Clinical Microbiology and Infectious Diseases at the University of the Witwatersrand Medical School are used for training and testing of the system. Infected erythrocytes are positively identified with a sensitivity of 85% and a positive predictive value (PPV) of 81%, which makes the method highly sensitive at diagnosing a complete sample provided many views are analysed. Species were correctly determined for 11 out of 15 samples.

  3. The innovation of the subspecialty of Paediatric Virology: An interview with Research Professor of Molecular Virology Anna Kramvis.

    Science.gov (United States)

    Mammas, Ioannis N; Spandidos, Demetrios A

    2017-10-01

    Professor Anna Kramvis, Research Professor of Molecular Virology at the University of the Witwatersrand in Johannesburg, South Africa, talks about direct-acting antiviral treatments against hepatitis C virus (HCV), as well as the perspective of the development of an effective vaccine against HCV. She emphasises the necessity of vaccination against hepatitis B virus (HBV), highlighting that it is very important that vaccination should be administered at birth in order to prevent mother-to-child transmission (MTCT) of HBV. Professor Kramvis states that vaccination against HBV is safe and that HBV and HCV infections are not contraindications for breastfeeding. Regarding the challenge of Paediatric Virology, she believes that it is a field that during the last years is increasing exponentially, while she concurs that Paediatric Virology subspecialty will be a popular choice for infectious diseases subspecialists. In the context of the 3rd Workshop on Paediatric Virology, which will be held in Athens on October 7th, 2017, Professor Kramvis will give her key lecture on MTCT of HBV and HCV.

  4. The uranium industry of South Africa

    International Nuclear Information System (INIS)

    McLean, C.S.

    1994-01-01

    This paper was originally published in 1954 and is reproduced in this centenary issue of the journal of the South African Institute of Mining and Metallurgy. South Africa's economy was (and is) based on mining. The early history of the uranium mining industry (until 1954) is discussed in detail, together with its status and economy. The first quantitative assessment of the uranium potential of the Witwatersrand goldfield was made in 1945 when it was reported that South Africa had one of the largest low-grade uranium fields in the world. The first metallurgical plants brought considerable benefit to the area. The process of uranium extraction was basically similar to that employed in the recovery of gold. It could be divided into the same three main headings: agitation, filtration and precipitation. It was predicted that the program, in full swing, would possibly consume as much as 20,000 tons of manganese ore a month, as the extraction process requires dioxide. It was for this reason that manganese recovery plants have been incorporated in the process. Other materials that were to be used in large quantities were lime, limestone, animal glue and water. Considering the increasing importance of uranium in the economy of the country, the question of secrecy was becoming a problem. At that time the demand for South African uranium was guaranteed by a ten-year agreement with the British and American authorities. 3 figs

  5. Influence of Mining Pollution on Metal Bioaccumulation and Biomarker Responses in Cave Dwelling Fish, Clarias gariepinus.

    Science.gov (United States)

    du Preez, Gerhard; Wepener, Victor

    2016-07-01

    Cave ecosystems remain largely unstudied and risk being severely degraded as a result of anthropogenic activities. The Wonderfontein Cave, situated in the extensive gold mining region of the Witwatersrand Basin, is one such system that hosts a population of Clarias gariepinus, which is exposed to the influx of polluted mine water from the Wonderfontein Spruit River. The aim of this study was to investigate the bioaccumulation of metals, as well as relevant biomarkers, in C. gariepinus specimens sampled from the Wonderfontein Cave during high (April 2013) and low (September 2013) flow surveys. Results were also compared to a surface population associated with the Wonderfontein Spruit River. There were temporal differences in metal bioaccumulation patterns and this was attributed to the lack of dilution during the low flow period. Metals associated with acid mine drainage, i.e. Co, Mn and Zn were significantly higher in the Wonderfontein Cave population and were reflected in an increase in oxidative stress biomarkers (catalase, protein carbonyls and superoxide dismutase) and the induction of metallothionein, a biomarker of metal exposure. The surface population was exposed to metals associated with geological weathering processes, i.e. Fe and Al.

  6. Sex determination from the radius and ulna in a modern South African sample.

    Science.gov (United States)

    Barrier, I L O; L'Abbé, E N

    2008-07-18

    With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.

  7. Blood, sweat and plaster casts: Reviewing the history, composition, and scientific value of the Raymond A. Dart Collection of African Life and Death Masks.

    Science.gov (United States)

    Houlton, T M R; Billings, B K

    2017-10-01

    This paper addresses the history, composition and scientific value of one of the most comprehensive facemask collections in Africa, the Raymond A. Dart Collection of African Life and Death Masks. Housed within the School of Anatomical Sciences at the University of the Witwatersrand (South Africa), it comprises 1110 masks (397 life, 487 death, 226 unknown). Life masks represent populations throughout Africa; death masks predominately southern Africa. Males preponderate by 75%. Recorded ages are error prone, but suggest most life masks are those of <35 year-olds, death masks of 36+ year-olds. A total of 241 masks have associated skeletons, 209 presenting a complete skull. Life masks date between 1927 and c.1980s, death masks 1933 and 1963. This historical collection presents uncanny associations with outmoded typological and evolutionary theories. Once perceived an essential scientific resource, performed craniofacial superimpositions identify the nose as the only stable feature maintained, with the remaining face best preserved in young individuals with minimal body fat. The facemask collection is most viable for teaching and research within the history of science, specifically physical anthropology, and presents some value to craniofacial identification. Future research will have to be conducted with appropriate ethical considerations to science and medicine. Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. Shedding new light on an old mystery: Early photographs of the Taung Child

    Directory of Open Access Journals (Sweden)

    Goran Štrkalj

    2012-10-01

    Full Text Available Although it was one of the most important events in the history of palaeoanthropology, many details of the Taung discovery and the events that followed it are still not completely elucidated. In this paper, we recount the events surrounding three early photographs (stored in the University of the Witwatersrand Archives showing the Taung Child skull being held in the hands of the renowned anthropologist Raymond Dart. Having, what seems to be, a mosaic of evidence both for and against, we deliberate upon whether the archival photographs presented here are among the first photographs of the fossil itself or are of the first plaster cast of the Taung Child which was prepared for the 1925 British Empire Exhibition held at Wembley, London. We interpreted the photographs and determined their provenance through analyses which included historical examination of published accounts of the Taung discovery and archival materials, as well as comparisons of the photographed material in question with both archival and current (digital, high quality photographs of the Taung fossil itself and Taung skull casts (as the skull underwent changes over time. We conclude that the early photographs presented here are of the original fossil itself and not of a cast. At the same time, these photographs represent some of the first pictorial depictions of the Taung Child skull.

  9. Ready-to-wear sexual politics: The semiotics of visibility on Wits Pride T-shirts

    Directory of Open Access Journals (Sweden)

    Tommaso M. Milani

    2015-09-01

    Full Text Available The aim of this article is to investigate T-shirts as semiotic tools of the politics of visibility, showing which role these sartorial artefacts may play in competing struggles for recognition in which gender and sexuality intersect with other axes of social categorisations. Drawing on a queer multimodal approach, the article offers an analysis of the four promotional T-shirts that were distributed each year between 2011 and 2014 by the Transformation and Employment Equity Office at the University of the Witwatersrand (Wits, Johannesburg, in the context of the annual Pride parade on campus. Our main argument is that changes over time in the design of Wits Pride T-shirts represent a shift both in what is claimed to be the main goal of campus sexual politics and in the proposed means to achieve such a goal. If one were to imagine that each T-shirt is a corporeal embodiment of Wits Pride, then this body has changed considerably in four years: from a gay man who is (supposedly ashamed of voicing his sexual identity; into a camp though masculine figure that loudly urges to counter racial division within same-sex desire; into a more multifaceted individual who proudly carries their gender and sexual uniqueness; and finally, into an activist who, in tension with the complex intersections that underpin discrimination, is perhaps a little reluctant to foreground gender and sexuality at all.

  10. A profile of students receiving counselling services at a university in post-apartheid South Africa.

    Science.gov (United States)

    Bowman, Brett; Payne, Jarrod

    2011-12-01

    The purpose of this study was to describe a profile of students seeking counselling at a racially diverse university in post-apartheid South Africa as a means to demonstrate the importance of routinely collecting and analysing student counselling data at university-based centres across the country. Student data were extracted from the only two counselling centres based at the University of the Witwatersrand in Johannesburg that provided services to 831 students during 2008. The 26 243 students that did not seek counselling during this period formed the comparison group. These data were analysed using logistic regression. Black, female and students within the 21-25 year age category were more likely to receive counselling, and presenting problems varied by population group. Given the country's past and continued levels of social asymmetry, we argue that the development of standardised university-based reporting systems able to describe the characteristics and presenting problems of students seeking counselling across South African universities should be prioritised by its higher education sector. Timely access to information of this kind is crucial to the generation of evidence-based mental health interventions in a population that is especially important to the country's development vision.

  11. New U Pb SHRIMP zircon age for the Schurwedraai alkali granite: Implications for pre-impact development of the Vredefort Dome and extent of Bushveld magmatism, South Africa

    Science.gov (United States)

    Graham, I. T.; De Waal, S. A.; Armstrong, R. A.

    2005-12-01

    The Schurwedraai alkali granite is one of a number of prominent ultramafic-mafic and felsic intrusions in the Neoarchaean to Palaeoproterozoic sub-vertical supracrustal collar rocks of the Vredefort Dome, South Africa. The alkali granite intruded the Neoarchaean Witwatersrand Supergroup and has a peralkaline to peraluminous composition. A new zircon SHRIMP crystallization age of 2052 ± 14 Ma for the Schurwedraai alkali granite places it statistically before the Vredefort impact event at 2023 ± 4 Ma and within the accepted emplacement interval of 2050-2060 Ma of the Bushveld magmatic event. The presence of the alkali granite and associated small ultramafic-mafic intrusions in the Vredefort collar rocks extends the southern extremity of Bushveld-related intrusions to some 120 km south of Johannesburg and about 150 km south of the current outcrop area of the Bushveld Complex. The combined effect of these ultramafic-mafic and felsic bodies may have contributed to a pronouncedly steep pre-impact geothermal gradient in the Vredefort area, and to the amphibolite-grade metamorphism observed in the supracrustal collar rocks of the Vredefort Dome.

  12. Acid mine drainage arising from gold mining activity in Johannesburg, South Africa and environs

    International Nuclear Information System (INIS)

    Naicker, K.; Cukrowska, E.; McCarthy, T.S.

    2003-01-01

    Ground water within the mining district is heavily contaminated and acidified. - The Witwatersrand region of South Africa is famous for its gold production and a major conurbation, centred on Johannesburg, has developed as a result of mining activity. A study was undertaken of surface and ground water in a drainage system in this area. Soils were also analysed from a site within the mining district. This study revealed that the ground water within the mining district is heavily contaminated and acidified as a result of oxidation of pyrite (FeS 2 ) contained within mine tailings dumps, and has elevated concentrations of heavy metals. Where the water table is close to surface, the upper 20 cm of soil profiles are severely contaminated by heavy metals due to capillary rise and evaporation of the ground water. The polluted ground water is discharging into streams in the area and contributes up to 20% of stream discharge, causing a lowering of pH of the stream water. Much of the metal load is precipitated in the stream: Fe and Mn precipitate as a consequence of oxidation, while other heavy metals are being removed by co-precipitation. The oxidation of iron has created a redox buffer which controls the pH of the stream water. The rate of oxidation and of dilution is slow and the deleterious effect of the addition of contaminated water persists for more than 10 km beyond the source

  13. ‘It’s not about money, it’s about my health’: determinants of participation and adherence among women in an HIV-HSV2 prevention trial in Johannesburg, South Africa

    Directory of Open Access Journals (Sweden)

    MacPhail C

    2012-08-01

    Full Text Available Catherine MacPhail,1 Sinead Delany-Moretlwe,1 Philippe Mayaud21Wits Reproductive Health and HIV Institute, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, South Africa; 2Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UKAbstract: High levels of adherence in clinical trials are essential for producing accurate intervention efficacy estimates. Adherence to clinical trial products and procedures is dependent on the motivations that drive participants. Data are presented to document reasons for trial participation and adherence to daily aciclovir for HSV-2 and HIV-1 genital shedding suppression among 300 HIV-1/HSV-2 seropositive women in South Africa. In-depth interviews after exit from the trial with 31 randomly selected women stratified by age and time since HIV diagnosis confirmed high levels of adherence measured during the trial. Main reasons for trial participation were related to seeking high-quality health care, which explains high levels of adherence in both study arms. Concerns that women would abuse reimbursements, fabricate data, and share or dump pills were not corroborated. Altruism is not a primary motivator in these settings where access to quality services is an issue. This study provides further evidence that good adherence of daily medication is possible in developing countries, particularly where study activities resonate with participants or fill an unmet need.Keywords: adherence, trial, HIV prevention, South Africa

  14. Water and the human culture of appropriation: the Vaal River up to 1956

    Directory of Open Access Journals (Sweden)

    Johann W.N. Tempelhoff

    2006-04-01

    Full Text Available There is discernable evidence of the human presence having historically appropriated the 1300 kilometer long Vaal River of South Africa as it extends itself from the Drakensberg Plateau into the arid Karoo region. This hard-working tributary of the Orange River, which was instrumental as a supply of water to the Witwatersrand, in the era of the region’s gold mines, has been used by humans in a variety of ways. First it was used as a route of communications, then as a borderline demarcating the territorial spaces of states and colonies. Later it was used for purposes of economic development. In the study the objective is to point towards the manner in which humans have influenced the river and its hinterland, particularly from the nineteenth century, up to the 1950s. The process of appropriation, it is argued, has had a different effect when humans laid claim to the river and its environment for social, economic and political purposes.

  15. Uranium Exploration, Resources and Production in South Africa 2009

    Energy Technology Data Exchange (ETDEWEB)

    Ainslie, L.C., E-mail: lee.ainslie@necsa.co.za [South African Nuclear Energy Agency (Necsa), Pretoria (South Africa)

    2014-05-15

    The paper gives a brief history of uranium mining in South Africa. The types of uranium deposits in South Africa are described and their distribution given. The majority of uranium is hosted as a by-product in the quartz-pebble conglomerates of the Witwatersrand Basin with lesser amounts in tabular sandstone and coal hosted deposits. The exploration activities of companies operating in South Africa are discussed and the reserves and resources identified are presented. A substantial increase in reserves has been recorded over the last two years because of intensive investigation of known deposits. Only a marginal increase in total resources was reported because of a lack of “greenfield” exploration. Production is far down from the levels achieved in the 1970s and 1980s. The surge in the uranium market resulted in a number of companies investigating their production options. The recent decline in the market has slowed down some of these activities and forced the closure of an operating mine. However a new mine has come into production and feasibility studies are being carried out on other deposits. The recently promulgated Nuclear Energy Policy for the Republic of South Africa defines Necsa’s role in nuclear fuel cycle and the uranium mining industry emphasizing security of supply. South African uranium resources will be able to supply all local needs for the foreseeable future. (author)

  16. Isotope hydrology and its impact in the developing world

    International Nuclear Information System (INIS)

    Verhagen, B.Th.

    2003-01-01

    Ground water has increasingly taken its place in the provision of safe, potable supply in the developing world. Large investments have been made in infrastructural development for rural ground water supply schemes, but far too little attention has been given to assess the sustainability of these supplies. Overexploitation of aquifers, evident in failing boreholes and deteriorating water quality, has become a world-wide concern. Developments in physics half a century ago established the basis of isotope hydrology. Radioactive isotopes give information on ground water dynamics and recharge rates whilst non-radioactive - or stable - isotopes indicate origins of ground water and delineate ground water bodies. Environmental isotope hydrology is increasingly seen as a powerful discipline in assessing ground water systems. This is particularly important in developing environments, where historical data is rarely available. Brief examples are presented of isotope applications to collaborative ground water studies conducted at the University of the Witwatersrand. Recharge estimates based on isotope 'snapshot' data conform well with results from subsequent long-term water level observations in the Kalahari of Botswana. The importance is demonstrated of irrigation return flow and pollution hazard to the Lomagundi dolomite of Zimbabwe. Isotopes suggest the source of high nitrate concentrations to an important ground water supply in Tanzania. Mechanisms of the release of arsenic into millions of tube wells in Bangladesh are put into perspective. Isotope hydrology as appropriate technology is highlighted in terms of its cost-effectiveness and the investigative empowerment of local investigators. (author)

  17. Tumour sleuths

    International Nuclear Information System (INIS)

    Beyers, M.; Springolo, E.; Conradie, J.D.

    1986-01-01

    Hepatocellular carcinoma is a common disease in South Africa and its identification difficult. Methods for the diagnosis of this disease includes the production of hybridoma cell lines by inoculating laboratory mice with a purified human tumour-associated antigen or the antigen-containing surface membranes or the intact cells. In the diagnosis of hepatocellular carcinoma, high concentrations of serum alpha fetoprotein (AFP) can be measured by means of radioimmunoassay techniques. The need for specific methods of diagnosis and treatment of hepatocellular carcinoma led to the investigation by the Isotope Production Centre at Pelindaba into the possibility of using radiolabelled monoclonal anti-AFP for diagnosis, and later, therapy of hepatocellular carcinoma. The monoclonal antibodies can also be labelled with 131 I. Recently the Department of Nuclear Medicine of the University of the Witwatersrand is conducting diagnostic trials on patients who have given their informed consent, to assess the specificity of 131 I radiolabelled anti-AFP monoclonal antibodies to hepatocellular carcinoma cells in humans. Although the investigation is still in its infancy, monoclonal antibodies may prove to be successful non-invasive agents for detecting tumors in early stages

  18. A tectonic reconstruction of accreted terranes along the paleo-Pacific margin of Gondwana

    Science.gov (United States)

    Bammel, Brandon

    The southern oceanic margin of Gondwana was nearly 40,000 km long or 24,854.8 miles. The southern margin was the result of the Terra Australis orogen. Spanning 18,000 km or 11,184.7 miles and is proposed as one of the largest and longest lived orogens in Earth history. The paleo-Pacific margin of Gondwana consisted of segments of the Australian-Antarctic craton, southern South America (modern Argentina and Chile), southern South Africa, Marie Byrdland, New Zealand and its adjacent continental shelf, the Ellsworth Mountains, and the Transantarctic Mountains. The process of terrane accretion has played a substantial part in the assembly of the continents as they look today. The paleo-Pacific margin of Gondwana was an active region of terrane accretion from the Neoproterozoic to the Late Mesozoic. This research study examines the accretion of terranes across the paleo-Pacific Gondwana margin to provide a comprehensive reconstruction. A paleogeographic basemap was created using PALEOMAP Project maps and the geology data was provided by the School of Geoscience from the University of Witwatersrand of South Africa. Location and data analyzed for terranes were collected building a PDF library of journal articles across numerous geological publications.

  19. Edinburgh, the Scottish pioneers of anatomy and their lasting influence in South Africa.

    Science.gov (United States)

    Correia, J C; Wessels, Q; Vorster, W

    2013-11-01

    The history of the origin of anatomy education in South Africa is the history of an arduous journey through time. The lasting influence of Edinburgh came in the form of Robert Black Thomson. He was a student and assistant of Sir William Turner who gave rise to the first chair of anatomy and the establishment of a department at the South African College, known today as University of Cape Town. Thomson was later succeeded by Matthew Drennan, a keen anthropologist, who was revered by his students. This Scottish link prevailed over time with the appointment of Edward Philip Stibbe as the chair of anatomy at the South African School of Mines and Technology, which later became the University of the Witwatersrand. Stibbe's successor, Raymond Arthur Dart, a graduate of the University of Sydney, was trained in an anatomy department sculpted on that of Edinburgh by Professor James Thomas Wilson. Wilson's influence at the University of Sydney can be traced back to Edinburgh and William Turner through Thomas Anderson Stuart. Both Dart and Robert Broom, another Scot, were considered as Africa's wild men by the late Professor Tobias. Here, the authors explore the Scottish link and origins of anatomy pedagogy in South Africa.

  20. Single cell genomics indicates horizontal gene transfer and viral infections in a deep subsurface Firmicutes population

    Directory of Open Access Journals (Sweden)

    Jessica eLabonté

    2015-04-01

    Full Text Available A major fraction of Earth's prokaryotic biomass dwells in the deep subsurface, where cellular abundances per volume of sample are lower, metabolism is slower, and generation times are longer than those in surface terrestrial and marine environments. How these conditions impact biotic interactions and evolutionary processes is largely unknown. Here we employed single cell genomics to analyze cell-to-cell genome content variability and signatures of horizontal gene transfer (HGT and viral infections in five cells of Candidatus Desulforudis audaxviator, which were collected from a three km-deep fracture water in the 2.9 Ga-old Witwatersrand Basin of South Africa. Between 0 and 32 % of genes recovered from single cells were not present in the original, metagenomic assembly of Desulforudis, which was obtained from a neighboring subsurface fracture. We found a transposable prophage, a retron, multiple clustered regularly interspaced short palindromic repeats (CRISPRs and restriction-modification systems, and an unusually high frequency of transposases in the analyzed single cell genomes. This indicates that recombination, HGT and viral infections are prevalent evolutionary events in the studied population of microorganisms inhabiting a highly stable deep subsurface environment.

  1. Human resources for research: building bridges through the Diaspora

    Directory of Open Access Journals (Sweden)

    Karen Hofman

    2015-11-01

    Full Text Available Background: The collaboration of scientists between the developed and the developing world is an opportunity to reverse the ‘brain drain' and to enable ‘brain circulation'. Objective: Attracting alumni from the Diaspora to strengthen the development of talented scientists will strengthen research in Africa. Design: In 2010, the Faculty of Health Sciences at the University of the Witwatersrand, South Africa (SA, created an Alumni Diaspora Programme to boost international research collaboration and networking between leading medical and health sciences alumni who now live and work at academic institutions abroad with academic colleagues ‘back home'. Based in Johannesburg, a gateway city attracting researchers from all over sub-Saharan Africa, this programme has the potential to capitalise on some of the intellectual capacity that was lost, mostly during the decades of apartheid, and to strengthen capacity, not just in SA, but across the continent. Results and Conclusions: The goal of this review is to highlight how this programme has stimulated collaborations and networking with international alumni.

  2. PREFACE: International Workshop on Discovery Physics at the LHC (Kruger2012)

    Science.gov (United States)

    Cleymans, Jean

    2013-08-01

    The second conference on 'Discovery Physics at the LHC' was held on 3-7 December 2012 at the Kruger Gate Hotel in South Africa. In total there were 110 participants from Armenia, Belgium, Brazil, Canada, Czech Republic, France, Germany, Greece, Israel, Italy, Norway, Poland, USA, Russia, Slovakia, Spain, Sweden, United Kingdom, Switzerland and South Africa. The latest results from the Large Hadron Collider, Brookhaven National Laboratory, Jefferson Laboratory and BABAR experiments, as well as the latest theoretical insights were presented. Set against the backdrop of the majestic Kruger National Park a very stimulating conference with many exchanges took place. The proceedings reflect the high standard of the conference. The financial contributions from the National Institute for Theoretical Physics (NITHeP), the SA-CERN programme, the UCT-CERN Research Centre, the University of Johannesburg, the University of the Witwatersrand and iThemba Labs—Laboratory for Accelerator Based Science are gratefully acknowledged. Jean Cleymans Chair of the Local Organizing Committee Local Organizing Committee Oana Boeriu Jean Cleymans Simon H Connell Alan S Cornell William A Horowitz Andre Peshier Trevor Vickey Zeblon Z Vilakazi Group picture

  3. PREFACE: International Workshop on Discovery Physics at the LHC (Kruger2014)

    Science.gov (United States)

    Cleymans, Jean

    2015-06-01

    The third biannual conference on 'Discovery Physics at the LHC' was held on December 1-6 2014 at the Kruger Gate Hotel in South Africa. Over 100 participants attended from Austria, Australia, Belgium, Brazil, Canada, China, the Czech Republic, France, Germany, Italy, the Netherlands, Norway, Poland, South Africa, Switzerland, the UK and the USA. The latest results from the Large Hadron Collider as well the latest theoretical insights were presented. With the majestic Kruger National Park in the background this led to a very stimulating conference with many exchanges taking place. The proceedings reflect the high level of the conference. The financial contributions from the SA-CERN programme, the UCT-CERN Research Centre, the University of Johannesburg, the University of the Witwatersrand and iThemba L.A.B.S. are gratefully acknowledged. Local Organizing Committee: Z. Buthelezi J. Cleymans (chair) S. H. Connell A. S. Cornell T. Dietel S. Förtsch N. Haasbroek A. Hamilton W. A. Horowitz B. Mellado Z. Z. Vilakazi S. Yacoob

  4. The development of the uranium and nuclear industry in South Africa, 1945 - 1970 : a historical study

    International Nuclear Information System (INIS)

    Janson, E.J.G.

    1995-12-01

    This thesis traces the historical development of nuclear research in South Africa between 1945 and 1970, starting with the efforts of metallurgists of South Africa and the Allied Nations to extract uranium from the gold ores of the Witwatersrand. During the 1950's seventeen uranium extraction plants formed a very important part of the country's industrial activity. The prospect of using South African uranium for nuclear power production (in the Western Cape area), led to the Atomic Energy Research and Development Programme investigation into nuclear energy production in South Africa. The programme provided for the refining of uranium for nuclear fuel, the establishment of a nuclear research centre at Pelindaba, the acquisition of a research reactor, and facilities for nuclear reactor research and uranium enrichment experiments. The two major projects that were initiated in the 1960's were the Pelinduna nuclear reactor project and experimentation on the vortex tube method for uranium enrichment (the Gas Cooling Project). An Investigation Committee was appointed by the Government to assess the viability of a pilot uranium enrichment plant. In 1970 it was announced that a process had been developed that was a combination of the separating element using uranium hexafluoride in hydrogen as the process fluid and a new cascade technique. 331 refs., 19 figs

  5. Exploring the Perceptions of Wits Academic Women About Women Empowerment and the Changing Roles of Women in 21st-Century South Africa

    Directory of Open Access Journals (Sweden)

    Evelyn Muberekwa

    2016-11-01

    Full Text Available Issues of women’s empowerment and gender inequality have been of paramount importance, particularly in the two decades since the Fourth World Conference on Women, Beijing, 1995. At that conference, the campaign for women’s empowerment was initiated to implement laws promoting gender equality. This research explored the perceptions of nine academic women at the University of the Witwatersrand with regard to women’s empowerment and the changing roles of women in a South African context in the 21st century. The research adopted a qualitative research methodology, and purposive sampling was utilized to select the study population. Data were collected in the form of semistructured interviews of approximately 30 to 60 min in duration, and thematic content analysis was applied to analyze the data. The data collected indicated that women in academia face challenges and experiences like other women in the workforce. These challenges and experiences are a result of the patriarchal nature of the workplace environment and the slow transformation at the university. It is also interesting to note that the gender roles of women in academia in their daily activities, married or single, are aggravated by the patriarchal nature of the broader society in which these women live.

  6. Elemental imaging of organic matter and associated metals in ore deposits using micro PIXE and micro-EBS

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, S., E-mail: fuchs@geomin.eu [Department of Earth and Planetary Science, McGill University, 3450 University Street, Montreal H3A 0E8 (Canada); Przybylowicz, W.J., E-mail: przybylowicz@tlabs.ac.za [Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. A. Mickiewicza 30, 30-059 Krakow (Poland); Williams-Jones, A.E., E-mail: anthony.williams-jones@mcgill.ca [Department of Earth and Planetary Science, McGill University, 3450 University Street, Montreal H3A 0E8 (Canada)

    2014-01-01

    Micro-PIXE and micro-EBS analyses were carried out on samples from the Au–U-bearing Carbon Leader Reef of the Witwatersrand in South Africa to investigate the role of organic matter in the formation of this deposit. Micro-PIXE and Micro-EBS shows a very complex metal distribution within the bitumen nodules and their interstitial spaces. The style of the gold distribution and its association with epigenetic minerals (REE phosphates, phyllosilicates) indicates that all observed gold migrated in aqueous solution and precipitated by reduction on the surfaces of the bitumen nodules. Uraninite occurrences are confined to the bitumen nodules, which supports the argument of a uraninite paleo-placer; however the pervasive distribution of uranium also supports the argument that uraninite is derived from organo-metallic complexes. This study shows that micro-PIXE is a powerful tool to characterize metals associated with hydrocarbons. However, the organic matrix, the complexity of the obtained spectra and the small size of the minerals have significant influence on the reliability of the quantitative data. Due to highly variable amounts of heavy metals (U, Au, Pb) the obtained micro-EBS results are of questionable quality.

  7. Parameters and characteristics governing cellular internalization and trans-barrier trafficking of nanostructures

    Directory of Open Access Journals (Sweden)

    Murugan K

    2015-03-01

    Full Text Available Karmani Murugan, Yahya E Choonara, Pradeep Kumar, Divya Bijukumar, Lisa C du Toit, Viness Pillay Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa Abstract: Cellular internalization and trans-barrier transport of nanoparticles can be manipulated on the basis of the physicochemical and mechanical characteristics of nanoparticles. Research has shown that these factors significantly influence the uptake of nanoparticles. Dictating these characteristics allows for the control of the rate and extent of cellular uptake, as well as delivering the drug-loaded nanosystem intra-cellularly, which is imperative for drugs that require a specific cellular level to exert their effects. Additionally, physicochemical characteristics of the nanoparticles should be optimal for the nanosystem to bypass the natural restricting phenomena of the body and act therapeutically at the targeted site. The factors at the focal point of emerging smart nanomedicines include nanoparticle size, surface charge, shape, hydrophobicity, surface chemistry, and even protein and ligand conjugates. Hence, this review discusses the mechanism of internalization of nanoparticles and ideal nanoparticle characteristics that allow them to evade the biological barriers in order to achieve optimal cellular uptake in different organ systems. Identifying these parameters assists with the progression of nanomedicine as an outstanding vector of pharmaceuticals. Keywords: nanoparticles, transport mechanisms, cellular uptake, size, shape, charge

  8. A Circle of Learning: The impact of a narrative multilingualism approach on in-service teachers’ literacy pedagogies

    Directory of Open Access Journals (Sweden)

    Belinda Mendelowitz

    2011-05-01

    Full Text Available This paper explores the impact of a narrative multilingualism approach on in-service primary school teachers who attended the Advanced Certi"cate of Education (ACE Languages course at the University of the Witwatersrand in 2009. The teachers wrote their own language narratives and were required to implement language narrative work in their classrooms. The paper is a case study of three teachers’ implementation of multilingual narrative pedagogy, and explores the ways in which each teacher translates this pedagogy into their specific contexts. Theoretically, the paper attempts to deepen and extend narrative multilingualism as an approach to language teaching. The notions of uptake and pedagogical translation are explored at various levels, namely, the teachers’ uptake of a multilingual narrative approach and the learners’ uptake. The most striking aspect of the data, across all teachers, is the process and dynamics unleashed in the classroom space. The process of sharing language narratives reconfigured dynamics in the classroom and opened up the classroom space for teachers and learners. The interventions that the pedagogy of narrative multilingualism afforded enabled the validation of linguistic diversity. In a society where xenophobia and linguicism is prevalent, such interventions can play a valuable role in changing attitudes and teaching learners to value difference. Furthermore, previously silenced learners found their voices and participated more in class activities.

  9. Human resources for research: building bridges through the Diaspora

    Science.gov (United States)

    Hofman, Karen; Kramer, Beverley

    2015-01-01

    Background The collaboration of scientists between the developed and the developing world is an opportunity to reverse the ‘brain drain' and to enable ‘brain circulation'. Objective Attracting alumni from the Diaspora to strengthen the development of talented scientists will strengthen research in Africa. Design In 2010, the Faculty of Health Sciences at the University of the Witwatersrand, South Africa (SA), created an Alumni Diaspora Programme to boost international research collaboration and networking between leading medical and health sciences alumni who now live and work at academic institutions abroad with academic colleagues ‘back home'. Based in Johannesburg, a gateway city attracting researchers from all over sub-Saharan Africa, this programme has the potential to capitalise on some of the intellectual capacity that was lost, mostly during the decades of apartheid, and to strengthen capacity, not just in SA, but across the continent. Results and Conclusions The goal of this review is to highlight how this programme has stimulated collaborations and networking with international alumni. PMID:26548635

  10. Budget impact analysis of antiretroviral less drug regimen simplification in HIV-positive patients on the Italian National Health Service

    Directory of Open Access Journals (Sweden)

    Restelli U

    2014-09-01

    Full Text Available Umberto Restelli,1,2 Massimo Andreoni,3 Andrea Antinori,4 Marzia Bonfanti,2 Giovanni Di Perri,5 Massimo Galli,6 Adriano Lazzarin,7 Giuliano Rizzardini,8,9 Davide Croce1,2 1Department of Community Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 2Centro di Ricerca in Economia e Management in Sanità e nel Sociale (CREMS, Università Carlo Cattaneo – LIUC, Castellanza (VA, Italy; 3Clinical Infectious Diseases, Tor Vergata University (PTV, Rome, Italy; 4Clinical Department, National Institute for Infectious Diseases "L. Spallanzani," Rome, Italy; 5Department of Medical Sciences, Infectious Diseases, Amedeo di Savoia Hospital, Turin, Italy; 6Third Division of Infectious Diseases, "Luigi Sacco" Hospital, Milan, Italy; 7Department of Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy; 8First and Second Divisions of Infectious Diseases, "Luigi Sacco" Hospital, Milan, Italy; 9School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa Background: Deintensification and less drug regimen (LDR antiretroviral therapy (ART strategies have proved to be effective in terms of maintaining viral suppression in human immunodeficiency virus (HIV-positive patients, increasing tolerability, and reducing toxicity of antiretroviral drugs administered to patients. However, the economic impact of these strategies have not been widely investigated. The aim of the study is to evaluate the economic impact that ART LDR could have on the Italian National Health Service (INHS budget. Methods: A budget impact model was structured to assess the potential savings for the INHS by the use of ART LDR for HIV-positive patients with a 3 year perspective. Data concerning ART cost, patient distribution within different ARTs, and probabilities for patients to change ART on a yearly basis were collected within four Italian infectious diseases departments, providing

  11. Pseudotachylitic breccia in mafic and felsic rocks

    Science.gov (United States)

    Kovaleva, Elizaveta; Huber, Matthew S.

    2017-04-01

    -gabbro, demonstrating clast transport between lithologies. PT melt in meta-gabbro has a two-phase structure: a phase free of granitic clasts, and a phase that contains granitic clasts. This also indicates that melt in both rock types was mobile during the same period of time, and that physical mixing and chemical exchange occurred between the two melts. Thus, PTB cuts across the contact between granite and gabbro, and is not restricted by the contact (e.g., Reimold and Colliston, 1994). These differences in nucleation and propagation of PTB based on rock type must be considered when discussing the formation mechanisms of impact-generated PTB. References: Gibson R.L., Reimold W.U., Ashley A.J., Koeberl C. (2002) Metamorphism of the Moon: A terrestrial analogue in the Vredefort dome, South Africa? Geology 30:475-478. Gibson R.L., Reimold W.U., Wallmach T. (1997) Origin of pseudotachylite in the lower Witwatersrand Supergroup, Vredefort Dome (South Africa): constraints from metamorphic studies. Tectonophysics 283:241-262. Reimold W.U., Colliston W.P. (1994) Pseudotachylites of the Vredefort Dome and the surrounding Witwatersrand Basin, South Africa. Geological Society of America Special Papers 293:177-196.

  12. Kriging: Understanding allays intimidation

    Science.gov (United States)

    Olea, R.A.

    1996-01-01

    In 1938 Daniel Gerhardus "Danie" Krige obtained an undergraduate degree in mining engineering and started a brilliant career centered on analyzing the gold and uranium mines in the Witwatersrand conglomerates of South Africa. He became interested in the disharmony between the poor reliability of reserve estimation reports and the magnitude of the economic decisions that were based on these studies. Back at the University of Witwatersrand, he wrote a master's thesis that began a revolution in mining evaluation methods. Krige was not alone in his research. Another mining engineer, Georges Matheron, a Frenchman, thought space data analysis belonged in a separate discipline, just as geophysics is a separate branch from physics. He named the new field geostatistics. Kriging is the name given in geostatistics to a collection of generalized linear regression techniques for the estimation of spatial phenomena. Pierre Carlier, another Frenchman, coined the term krigeage in the late 1950s to honor Krige's seminal work. Matheron anglicized the term to kriging when he published a paper for English-speaking readers. France dominated the development and application of geostatistics for several years. However, geostatistics in general, and kriging in particular, are employed by few and are regarded with apprehension by many. One of the possible applications of kriging is in computer mapping. Computer contouring methods can be grouped into two families: triangulation and gridding. The former is a direct procedure in which the contour lines are computed straight from the data by partitioning the sampling area into triangles with one observation per vertex. Kriging belongs in the gridding family. A grid is a regular arrangement of locations or nodes. In the gridding method the isolines are determined from interpolated values at the nodes. The difference between kriging and other weighting methods is in the calculation of the weights. Even for the simplest form of kriging, the

  13. Sexual autonomy and contraceptive use among women in Nigeria: findings from the Demographic and Health Survey data

    Directory of Open Access Journals (Sweden)

    Viswan SP

    2017-08-01

    Full Text Available Saritha P Viswan,1 T K Sundari Ravindran,1,2 Ngianga-Bakwin Kandala,1,3,4 Max G Petzold,1,5 Sharon Fonn1 1School of Public Health, University of the Witwatersrand, Johannesburg, South Africa; 2Achutha Menon Centre for Health Science Studies, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India; 3Division of Epidemiology and Biostatistics, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa; 4Department of Mathematics, Physics and Electrical Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, UK; 5Department of Public Health and Community Medicine, University of Gothenburg, Gothenburg, Sweden Context: The persistent low contraceptive use and high fertility in Nigeria despite improvements in educational achievements calls for an examination of the role of factors, which may moderate the use of modern contraception. This article explores the influence of sexual autonomy on the use of modern contraceptive methods among women and its relative importance compared with other, more traditional, indicators of women’s autonomy such as education and occupation.Data and methods: Data from two Demographic and Health Surveys (DHS, 2008 and 2013, were used in this study. An index of sexual autonomy was constructed by combining related DHS variables, and its association with current use of modern contraception was examined at each time point as well as over time using multivariate regression analysis.Results: The observed prevalence for use of modern contraception was 2.8 and 2.6 times higher among women who had high sexual autonomy in 2008 and 2013, respectively. The corresponding figures for women with secondary or higher education were 8.2 and 11.8 times higher, respectively, compared with women with no education. But after controlling for wealth index, religion, place of residence, autonomy and experience of intimate partner violence (IPV

  14. Treatment outcomes of HIV-positive patients on first-line antiretroviral therapy in private versus public HIV clinics in Johannesburg, South Africa

    Directory of Open Access Journals (Sweden)

    Moyo F

    2016-03-01

    Full Text Available Faith Moyo,1 Charles Chasela,2,3 Alana T Brennan,1,4 Osman Ebrahim,5 Ian M Sanne,1,6 Lawrence Long,1 Denise Evans1 1Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 2Epidemiology and Biostatistics Department, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 3Epidemiology and Strategic Information (ESI, HIV/AIDS/STIs and TB, Human Sciences Research Council, Pretoria, South Africa; 4Center for Global Health and Development, Boston University, Boston, MA, USA; 5Brenthurst Clinic, Parktown, South Africa; 6Right to Care, Helen Joseph Hospital, Westdene, Johannesburg, South Africa Background: Despite the widely documented success of antiretroviral therapy (ART, stakeholders continue to face the challenges of poor HIV treatment outcomes. While many studies have investigated patient-level causes of poor treatment outcomes, data on the effect of health systems on ART outcomes are scarce.Objective: We compare treatment outcomes among patients receiving HIV care and treatment at a public and private HIV clinic in Johannesburg, South Africa.Patients and methods: This was a retrospective cohort analysis of ART naïve adults (≥18.0 years, initiating ART at a public or private clinic in Johannesburg between July 01, 2007 and December 31, 2012. Cox proportional-hazards regression was used to identify baseline predictors of mortality and loss to follow-up (>3 months late for the last scheduled visit. Generalized estimating equations were used to determine predictors of failure to suppress viral load (≥400 copies/mL while the Wilcoxon rank-sum test was used to compare the median absolute change in CD4 count from baseline to 12 months post-ART initiation.Results: 12,865 patients initiated ART at the public clinic compared to 610 at the private

  15. Cost-effectiveness analysis of dolutegravir plus backbone compared with raltegravir plus backbone, darunavir+ritonavir plus backbone and efavirenz/tenofovir/emtricitabine in treatment naïve and experienced HIV-positive patients

    Directory of Open Access Journals (Sweden)

    Restelli U

    2017-06-01

    Full Text Available Umberto Restelli,1,2 Giuliano Rizzardini,3,4 Andrea Antinori,5 Adriano Lazzarin,6 Marzia Bonfanti,1 Paolo Bonfanti,7 Davide Croce1,2 1Centre for Research on Health Economics, Social and Health Care Management, LIUC – Università Cattaneo, Castellanza, Varese, Italy; 2School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 3First and Second Divisions of Infectious Diseases, “Luigi Sacco” Hospital, Milan, Italy; 4School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 5National Institute for Infectious Diseases “L Spallanzani”, Rome, 6Department of Infectious Diseases, San Raffaele Scientific Institute, 7Department of Infectious and Tropical Diseases, A Manzoni Hospital, Lecco, Italy Background: In January 2014, the European Medicines Agency issued a marketing authorization for dolutegravir (DTG, a second-generation integrase strand transfer inhibitor for HIV treatment. The study aimed at determining the incremental cost-effectiveness ratio (ICER of the use of DTG+backbone compared with raltegravir (RAL+backbone, darunavir (DRV+ritonavir(r+backbone and efavirenz/tenofovir/emtricitabine (EFV/TDF/FTC in HIV-positive treatment-naïve patients and compared with RAL+backbone in treatment-experienced patients, from the Italian National Health Service’s point of view.Materials and methods: A published Monte Carlo Individual Simulation Model (ARAMIS-DTG model was used to perform the analysis. Patients pass through mutually exclusive health states (defined in terms of diagnosis of HIV with or without opportunistic infections [OIs] and cardiovascular disease [CVD] and successive lines of therapy. The model considers costs (2014 and quality of life per monthly cycle in a lifetime horizon. Costs and quality-adjusted life years (QALYs are dependent on OI, CVD, AIDS events, adverse events and antiretroviral therapies.Results: In

  16. The contribution of the Precambrian continental lithosphere to global H2 production.

    Science.gov (United States)

    Lollar, Barbara Sherwood; Onstott, T C; Lacrampe-Couloume, G; Ballentine, C J

    2014-12-18

    Microbial ecosystems can be sustained by hydrogen gas (H2)-producing water-rock interactions in the Earth's subsurface and at deep ocean vents. Current estimates of global H2 production from the marine lithosphere by water-rock reactions (hydration) are in the range of 10(11) moles per year. Recent explorations of saline fracture waters in the Precambrian continental subsurface have identified environments as rich in H2 as hydrothermal vents and seafloor-spreading centres and have suggested a link between dissolved H2 and the radiolytic dissociation of water. However, extrapolation of a regional H2 flux based on the deep gold mines of the Witwatersrand basin in South Africa yields a contribution of the Precambrian lithosphere to global H2 production that was thought to be negligible (0.009 × 10(11) moles per year). Here we present a global compilation of published and new H2 concentration data obtained from Precambrian rocks and find that the H2 production potential of the Precambrian continental lithosphere has been underestimated. We suggest that this can be explained by a lack of consideration of additional H2-producing reactions, such as serpentinization, and the absence of appropriate scaling of H2 measurements from these environments to account for the fact that Precambrian crust represents over 70 per cent of global continental crust surface area. If H2 production via both radiolysis and hydration reactions is taken into account, our estimate of H2 production rates from the Precambrian continental lithosphere of 0.36-2.27 × 10(11) moles per year is comparable to estimates from marine systems.

  17. Design of a new front-end electronics test-bench for the upgraded ATLAS detector's Tile Calorimeter

    International Nuclear Information System (INIS)

    Kureba, C O; Govender, M; Hofsajer, I; Ruan, X; Sandrock, C; Spoor, M

    2015-01-01

    The year 2022 has been scheduled to see an upgrade of the Large Hadron Collider (LHC), in order to increase its instantaneous luminosity. The High Luminosity LHC, also referred to as the upgrade Phase-II, means an inevitable complete re-design of the read-out electronics in the Tile Calorimeter (TileCal) of the A Toroidal LHC Apparatus (ATLAS) detector. Here, the new read-out architecture is expected to have the front-end electronics transmit fully digitized information of the detector to the back-end electronics system. Fully digitized signals will allow more sophisticated reconstruction algorithms which will contribute to the required improved triggers at high pile-up. In Phase II, the current Mobile Drawer Integrity ChecKing (MobiDICK) test-bench will be replaced by the next generation test-bench for the TileCal superdrawers, the new Prometeo (A Portable ReadOut ModulE for Tilecal ElectrOnics). Prometeo is a portable, high-throughput electronic system for full certification of the front-end electronics of the ATLAS TileCal. It is designed to interface to the fast links and perform a series of tests on the data to assess the certification of the electronics. The Prometeo's prototype is being assembled by the University of the Witwatersrand and installed at CERN for further developing, tuning and tests. This article describes the overall design of the new Prometeo, and how it fits into the TileCal electronics upgrade. (paper)

  18. Stable isotope compositions of quartz pebbles and their fluid inclusions as tracers of sediment provenance: Implications for gold- and uranium-bearing quartz pebble conglomerates

    Energy Technology Data Exchange (ETDEWEB)

    Vennemann, T.W.; Kesler, S.E.; O' Neil, J.R. (Univ. of Michigan, Ann Arbor (United States))

    1992-09-01

    Oxygen isotope compositions of pebbles from late Archean to paleo-Proterozoic gold- and/or uranium-bearing oligomictic quartz pebble conglomerates of the Witwatersrand district, South Africa, and Huronian Supergroup, Canada, were determined in an attempt to define the nature of the source terrain. The [delta][sup 18]O values of quartz pebbles within any one sample typically vary by [approximately] 4[per thousand] or more, but occasionally by as much as 8[per thousand], even for adjacent pebbles within the same hand specimen. In addition, adjacent quartz pebbles of widely contrasting [delta][sup 18]O values also preserve distinct isotopic signatures of their fluid inclusions. This overall heterogeneity suggests that the pebbles did not undergo significant oxygen isotope exchange after incorporation in the conglomerates. Therefore, oxygen isotope analyses of such quartz pebbles, in combination with a detailed investigation of their mineral and fluid inclusions, can provide a useful method for characterizing pebble populations and hence dominant sediment source modes. Comparison of values found in this study with [delta][sup 18]O values of quartz from Archean granites, pegmatites, and mesothermal greenstone gold veins, i.e., [delta][sup 18]O values of sources commonly proposed for the conglomerate ores, suggests that uranium is derived from a granitic source, whereas gold has a mesothermal greenstone gold source. Low [delta][sup 18]O values of chert pebbles (9[per thousand] to 11.5[per thousand]) relative to those expected for Archean and Proterozoic marine cherts (commonly [ge] 17[per thousand]) effectively exclude marine cherts, and therefore, auriferous iron formations and exhalatives, as likely sources of gold.

  19. Stable isotope compositions of quartz pebbles and their fluid inclusions as tracers of sediment provenance: Implications for gold- and uranium-bearing quartz pebble conglomerates

    International Nuclear Information System (INIS)

    Vennemann, T.W.; Kesler, S.E.; O'Neil, J.R.

    1992-01-01

    Oxygen isotope compositions of pebbles from late Archean to paleo-Proterozoic gold- and/or uranium-bearing oligomictic quartz pebble conglomerates of the Witwatersrand district, South Africa, and Huronian Supergroup, Canada, were determined in an attempt to define the nature of the source terrain. The δ 18 O values of quartz pebbles within any one sample typically vary by ∼ 4 per-thousand or more, but occasionally by as much as 8 per-thousand, even for adjacent pebbles within the same hand specimen. In addition, adjacent quartz pebbles of widely contrasting δ 18 O values also preserve distinct isotopic signatures of their fluid inclusions. This overall heterogeneity suggests that the pebbles did not undergo significant oxygen isotope exchange after incorporation in the conglomerates. Therefore, oxygen isotope analyses of such quartz pebbles, in combination with a detailed investigation of their mineral and fluid inclusions, can provide a useful method for characterizing pebble populations and hence dominant sediment source modes. Comparison of values found in this study with δ 18 O values of quartz from Archean granites, pegmatites, and mesothermal greenstone gold veins, i.e., δ 18 O values of sources commonly proposed for the conglomerate ores, suggests that uranium is derived from a granitic source, whereas gold has a mesothermal greenstone gold source. Low δ 18 O values of chert pebbles (9 per-thousand to 11.5 per-thousand) relative to those expected for Archean and Proterozoic marine cherts (commonly ≥ 17 per-thousand) effectively exclude marine cherts, and therefore, auriferous iron formations and exhalatives, as likely sources of gold

  20. "Where art thou Sesotho?": Exploring the linguistic landscape of Wits University

    Directory of Open Access Journals (Sweden)

    Kadenge, Maxwell

    2015-12-01

    Full Text Available The article seeks to examine if the University of the Witwatersrand (Wits’s language policy on paper is visually reflected on the linguistic landscape of the institution. The objective of this policy is to promote multilingualism, especially the status elevation of Sesotho to become a medium of instruction alongside English and a field of academic study and research. Masoke-Kadenge and Kadenge (2013 note that conceptual flaws within the policy, financial constraints and lack of political will were some of the challenges that militated against the successful implementation of this policy. Today, twelve years after the adoption of this policy, Wits is largely monolingual. This article adopts an expanded view of language policy and explores the linguistic landscape of Wits with the goal of providing invaluable insights into the sociolinguistic situation at the institution. The main focus is on language visibility on public signage in the form of names of buildings like libraries, lecture venues and laboratories, warning notices and directions, among others, and important documentation like employment contracts, e-mails and newsletters at the Braamfontein East campus. The analysis also extends to the university’s website. The findings from this study show that the linguistic landscape of Wits is largely a reflection of the failed institutional language policy. It symbolically reproduces an old language ideology of a monolingual – English-based –university, which goes against the spirit of the National Language Policy Framework (Department of Arts and Culture, 2002 which compels South African universities to transform and develop language policies that accommodate linguistic, cultural and racial diversity.

  1. Recent trends in research and development work on the processing of uranium ore in South Africa

    International Nuclear Information System (INIS)

    James, H.E.

    1976-07-01

    The rapid increases in the price of gold and uranium in recent years have coincided with an unprecedented increase in working costs at South African gold mines. A re-examination of the existing flowsheets for the recovery of uranium, gold, and pyrite from Witwatersrand ores, in the light of these economic trends, has resulted in the identification of a number of profitable areas for research and development. The main topics under investigation in South Africa in the processing of uranium ore are the use of physical methods of concentration such as flotation, gravity concentration, and wet high-intensity magnetic separation; the wider adoption of the 'reverse leach', in which prior acid leaching for uranium improves the subsequent extraction of gold; the use of higher leaching temperatures and higher concentrations of ferric ion in the leach to increase the percentage of uranium extracted, including the production of ferric ion from recycled solutions; the application of pressure leaching to the recovery of uranium from low-grade ores and concentrates; the development of a continuous ion-exchange contactor capable of handling dilute slurries, so that simpler and cheaper techniques of solid-liquid separation can be used instead of the expensive filtration and clarification steps, and the improvement of instrumentation for the control of additions of sulphuric acid and manganese dioxide to the leach. A brief description is given of the essential features of the new or improved processing techniques under development that hold promise of full-scale application at existing or future uranium plants [af

  2. Recent trends in research and development work on the processing of uranium ore in South Africa

    International Nuclear Information System (INIS)

    James, H.E.

    1976-01-01

    The rapid increases in the price of gold and uranium in recent years have coincided with an unprecedented increase in working costs at South African gold mines. A re-examination of the existing flowsheets for the recovery of uranium, gold and pyrite from Witwatersrand ores, in the light of these economic trends, has resulted in the identification of a number of profitable areas for research and development. The main topics under investigation in South Africa in the processing of uranium ore are the use of physical methods of concentration such as flotation, gravity concentration and wet high-intensity magnetic separation; the wider adoption of the 'reverse leach', in which prior acid leaching for uranium improves the subsequent extraction of gold; the use of higher leaching temperatures and higher concentrations of ferric ion in the leach to increase the percentage of uranium extracted, including the production of ferric ion from recycled solutions; the application of pressure leaching to the recovery of uranium from low-grade ores and concentrates; the development of a continuous ion-exchange contactor capable of handling dilute slurries, so that simpler and cheaper techniques of solid/liquid separation can be used instead of the expensive filtration and clarification steps, and the improvement of instrumentation for the control of additions of sulphuric acid and manganese dioxide to the leach. A brief description is given of the essential features of the new or improved processing techniques under development that hold promise of full-scale application at existing or future uranium plants

  3. The process of installing REDCap, a web based database supporting biomedical research: the first year.

    Science.gov (United States)

    Klipin, M; Mare, I; Hazelhurst, S; Kramer, B

    2014-01-01

    Clinical and research data are essential for patient care, research and healthcare system planning. REDCapTM is a web-based tool for research data curatorship developed at Vanderbilt University in Nashville, USA. The Faculty of Health Sciences at the University of the Witwatersrand, Johannesburg South Africa identified the need for a cost effective data management instrument. REDCap was installed as per the user agreement with Vanderbilt University in August 2012. In order to assist other institutions that may lack the in-house Information Technology capacity, this paper describes the installation and support of REDCap and incorporates an analysis of user uptake over the first year of use. We reviewed the staffing requirements, costs of installation, process of installation and necessary infrastructure and end-user requests following the introduction of REDCap at Wits. The University Legal Office and Human Research Ethics Committee were consulted regarding the REDCap end-user agreement. Bi-monthly user meetings resulted in a training workshop in August 2013. We compared our REDCap software user numbers and records before and after the first training workshop. Human resources were recruited from existing staff. Installation costs were limited to servers and security certificates. The total costs to provide a functional REDCap platform was less than $9000. Eighty-one (81) users were registered in the first year. After the first training workshop the user numbers increased by 59 in one month and the total number of active users to 140 by the end of August 2013. Custom software applications for REDCap were created by collaboration between clinicians and software developers. REDCap was installed and maintained at limited cost. A small number of people with defined skills can support multiple REDCap users in two to four hours a week. End user training increased in the number of users, number of projects created and the number of projects moved to production.

  4. Costs of a school-based dental mobile service in South Africa.

    Science.gov (United States)

    Molete, M P; Chola, L; Hofman, K J

    2016-10-19

    The burden of untreated tooth decay remains high and oral healthcare utilisation is low for the majority of children in South Africa. There is need for alternative methods of improving access to low cost oral healthcare. The mobile dental unit of the University of the Witwatersrand (Wits) has been operational for over 25 years, providing alternative oral healthcare to children and adults who otherwise would not have access. The aim of this study was to conduct a cost-analysis of a school based oral healthcare program in the Wits mobile dental unit. The objectives were to estimate the general costs of the school based program, costs of oral healthcare per patient and the economic implications of providing services at scale. In 2012, the Wits mobile dental unit embarked on a 5 month project to provide oral healthcare in four schools located around Johannesburg. Cost and service use data were retrospectively collected from the program records for the cost analysis, which was undertaken from a provider perspective. The costs considered included both financial and economic costs. Capital costs were annualised and discounted at 6 %. One way sensitivity tests were conducted for uncertain parameters. The total economic costs were R813.701 (US$76,048). The cost of screening and treatment per patient were R331 (US$31) and R743 (US$69) respectively. Furthermore, fissure sealants cost the least out of the treatments provided. The sensitivity analysis indicated that the Wits mobile dental unit was cost efficient at 25 % allocation of staff time and that a Dental Therapy led service could save costs by 9.1 %. Expanding the services to a wider population of children and utilising Dental Therapists as key personnel could improve the efficiency of mobile dental healthcare provision.

  5. Radon generation and transport in and around a gold mine tailings dam in South Africa

    International Nuclear Information System (INIS)

    Speelman, W.J.; Lindsay, R.; Newman, R.T.; Meijer, R.J. de

    2006-01-01

    Naturally Occurring Radioactive Material (N.O.R.M.) occurs in most soil and rock, and by mining and mineral processing, some of the radionuclides are significantly enhanced. An in-situ gamma-ray detector called M.E.D.U.S.A., has been used to produce a map of relative activity concentrations in a gold mine tailings dam on the Witwatersrand in South Africa. A CsI(Na) scintillation detector is used in this system. M.E.D.U.S.A. spectra obtained from the survey were analyzed using the Full-Spectrum Analysis (F.S.A.) procedure to compute the 40 K, 238 U and 232 Th activity concentrations. The activity concentrations are used with global positioning data (G.P.S.) to produce the concentration maps. A hyper-pure germanium gamma-ray detector (Hp Ge) was used to measure gamma-rays from the naturally occurring nuclides for soil samples taken at different points on the site to calibrate the M.E.D.U.S.A. system. Radon soil gas measurements were performed at certain points on the mine tailings with a continuous radon monitor; R.A.D.7, and emanation coefficients were measured with electret technology. These parameters have been combined with the activity concentrations to obtain an average radon exhalation rate of about 0.1 Bq.m -2 .s -1 (with an uncertainty of about 20%) from the tailings dam. The purpose of the study is to also review and develop a mathematical model for radon activity concentration predictions in gold mine dumps. (authors)

  6. Impact of socio-economic factors on quality of life in patients on continuous ambulatory peritoneal dialysis in an African setting.

    Science.gov (United States)

    Okaka, E I; Davies, M; Ahmed, M; Naidoo, S; Naicker, S

    2014-01-01

    Quality of life (QOL) is an important outcome following the treatment of disease. It is influenced by physical, psychological, social and economic factors. We proposed to determine the effect of some socioeconomic factors on QOL of patients on CAPD. A cross sectional study in which all patients on CAPD attending three clinics attached to the University of the Witwatersrand, Johannesburg were recruited excluding those with intercurrent illness. The WHO quality of life instrument, WHOQOL-Bref, was used to measure QOL. The patients were grouped according to marital status, highest level of education attained, income, employment, and QOL domain scores were compared using ANOVA and Student t test. A total of 140 patients comprising 80 males and 40 females were assessed. The mean age of patients was 41.9 ± 11.5 years, 95%of patients were black, 44.3% married, 69.3% had secondary education, 22% were employed and 51.4% had a monthly income of less than five thousand Rand (500 US dollars). Single patients scored better in the social relationships domain compared to separated patients (p=0.02, CI: 5.6-32.9). The group with secondary education scored low in the psychological domain compared with those with primary education (p=0.02, CI: 1.35-15.8) and those with tertiary education (p=0.02, CI: 1.72-18.07).The highest income group had best scores in all domains except the physical domain. Those in employment had better scores in the physical domain (p=0.04, CI: 0.356-12.549). Income had the most impact on QOL in study participants.

  7. An Outbreak of Lymphocutaneous Sporotrichosis among Mine-Workers in South Africa.

    Science.gov (United States)

    Govender, Nelesh P; Maphanga, Tsidiso G; Zulu, Thokozile G; Patel, Jaymati; Walaza, Sibongile; Jacobs, Charlene; Ebonwu, Joy I; Ntuli, Sindile; Naicker, Serisha D; Thomas, Juno

    2015-09-01

    The largest outbreak of sporotrichosis occurred between 1938 and 1947 in the gold mines of Witwatersrand in South Africa. Here, we describe an outbreak of lymphocutaneous sporotrichosis that was investigated in a South African gold mine in 2011. Employees working at a reopened section of the mine were recruited for a descriptive cross-sectional study. Informed consent was sought for interview, clinical examination and medical record review. Specimens were collected from participants with active or partially-healed lymphocutaneous lesions. Environmental samples were collected from underground mine levels. Sporothrix isolates were identified by sequencing of the internal transcribed spacer region of the ribosomal gene and the nuclear calmodulin gene. Of 87 male miners, 81 (93%) were interviewed and examined, of whom 29 (36%) had skin lesions; specimens were collected from 17 (59%). Sporotrichosis was laboratory-confirmed among 10 patients and seven had clinically-compatible lesions. Of 42 miners with known HIV status, 11 (26%) were HIV-infected. No cases of disseminated disease were detected. Participants with ≤ 3 years' mining experience had a four times greater odds of developing sporotrichosis than those who had been employed for >3 years (adjusted OR 4.0, 95% CI 1.2-13.1). Isolates from 8 patients were identified as Sporothrix schenckii sensu stricto by calmodulin gene sequencing while environmental isolates were identified as Sporothrix mexicana. S. schenckii sensu stricto was identified as the causative pathogen. Although genetically distinct species were isolated from clinical and environmental sources, it is likely that the source was contaminated soil and untreated wood underground. No cases occurred following recommendations to close sections of the mine, treat timber and encourage consistent use of personal protective equipment. Sporotrichosis is a potentially re-emerging disease where traditional, rather than heavily mechanised, mining techniques are

  8. An Outbreak of Lymphocutaneous Sporotrichosis among Mine-Workers in South Africa.

    Directory of Open Access Journals (Sweden)

    Nelesh P Govender

    2015-09-01

    Full Text Available The largest outbreak of sporotrichosis occurred between 1938 and 1947 in the gold mines of Witwatersrand in South Africa. Here, we describe an outbreak of lymphocutaneous sporotrichosis that was investigated in a South African gold mine in 2011.Employees working at a reopened section of the mine were recruited for a descriptive cross-sectional study. Informed consent was sought for interview, clinical examination and medical record review. Specimens were collected from participants with active or partially-healed lymphocutaneous lesions. Environmental samples were collected from underground mine levels. Sporothrix isolates were identified by sequencing of the internal transcribed spacer region of the ribosomal gene and the nuclear calmodulin gene.Of 87 male miners, 81 (93% were interviewed and examined, of whom 29 (36% had skin lesions; specimens were collected from 17 (59%. Sporotrichosis was laboratory-confirmed among 10 patients and seven had clinically-compatible lesions. Of 42 miners with known HIV status, 11 (26% were HIV-infected. No cases of disseminated disease were detected. Participants with ≤ 3 years' mining experience had a four times greater odds of developing sporotrichosis than those who had been employed for >3 years (adjusted OR 4.0, 95% CI 1.2-13.1. Isolates from 8 patients were identified as Sporothrix schenckii sensu stricto by calmodulin gene sequencing while environmental isolates were identified as Sporothrix mexicana.S. schenckii sensu stricto was identified as the causative pathogen. Although genetically distinct species were isolated from clinical and environmental sources, it is likely that the source was contaminated soil and untreated wood underground. No cases occurred following recommendations to close sections of the mine, treat timber and encourage consistent use of personal protective equipment. Sporotrichosis is a potentially re-emerging disease where traditional, rather than heavily mechanised, mining

  9. Application of Electrical Resistivity Method for Detecting Shallow Old Gold Mine Workings: An Example from Boksburg, South Africa

    Science.gov (United States)

    Diop, S.; Chirenje, E.

    2011-12-01

    Subsidence has been observed at several locations along the northern perimeter of the Central Witwatersrand Mining Basin south of Johannesburg, South Africa. Previous studies have defined the extent and distribution of hundreds of open ventilation shafts and surface collapses linked to areas of known and suspected shallow undermining. Many collapses appear to be in a meta-stable state prone to further collapse, which could and have led to casualties. Identification of zones of incipient instability is therefore an urgent state responsibility to protect life and property, as much of these abandoned mine lands have been invaded by shack dwellers. This paper outlines the results of an investigation using 2D electrical resistivity tomography (ERT) in combination with a standard geotechnical engineering drilling exploration, with the aim of identifying areas of incipient instability and possible future collapse. The electrical resistivity data were acquired via a network of intersecting survey lines using a SYSCAL Pro multimode resistivity imaging system equipped with 72 electrodes. The dipole-dipole and the Schlumberger arrays with an electrode spacing of 5 and 10 m were used. Inversion of the data was carried out using the commercially available software package RES2DINV. Analysis of the electrical resistivity data and conventional site investigation data proved to be a highly effective means of characterizing dangerous, abandoned mine openings of various sizes, depths and origins. Survey results also successfully confirmed the position of known shafts and shallow underground workings. These appeared as electrically well-defined features corresponding extremely closely to both underground plans and invasive site investigation data. The findings obtained from this study offer practical considerations for modeling shallow subsurface conditions, along the Boksburg area; to enable the reliable identification of hazardous areas constituting a potential threat to human

  10. The value of the WIRHE Scholarship Programme in training health professionals for rural areas: Views of participants.

    Science.gov (United States)

    Mapukata, Nontsikelelo O; Couper, Ian; Smith, Jocelyn

    2017-10-13

    Rural hospitals in South Africa, as elsewhere, face enduring shortages of, and challenges in attracting and retaining, suitably qualified staff. The Wits Initiative for Rural Health Education (WIRHE), based at the University of the Witwatersrand but covering three universities, is a rural scholarship programme established to find local solutions to these challenges in the North West and Mpumalanga provinces. The purpose of this evaluation was to ascertain whether the WIRHE project was achieving its objectives. This article draws from an evaluation commissioned by the Swiss-South African Cooperative Initiative, a major funder of the programme when WIRHE was launched in 2003. Qualitative interviews were conducted either as face-to-face meetings or telephonically with 21 WIRHE students and graduates. Content analysis was undertaken to identify common themes. There was a consistency in the findings as the students and graduates reported similar experiences. Many of the participants were overwhelmed by their initial challenges of having to adapt to a different language, an institutional culture and resources that they previously did not have access to. The participants acknowledged the role of WIRHE staff in facilitating the transition from home to university and, in particular, the value of the financial and academic support. The geographic distance to Wits presented a challenge for the Pretoria- and Sefako Makgatho-based students. The holiday work affirmed clinical advantages for WIRHE students and heightened students' interest in becoming healthcare workers. WIRHE's key success factors are the financial, academic and emotional support offered to students. WIRHE achieved its objectives based on a principled strategic approach and an understanding that students from rural backgrounds are more likely to return to rural areas. The study supports the value of structured support programmes for students of rural origin as they pursue their studies.

  11. Uranium in South Africa: 1983 assessment of resources and production

    International Nuclear Information System (INIS)

    1984-06-01

    NUCOR assesses South Africa's uranium resource and production capabilities on an ongoing basis. Assessments are carried out in close co-operation with the mining companies and the Government Mining Engineer. In carrying out this evaluation, the classification recommended by the NEA/IAEA Working Party on Uranium Resources is followed. In order to preserve company confidentiality, the details of the findings are released in summary form only. Within South Africa, uranium occurrences are found in Precambrian quartz-pebble conglomerates, Precambrian alkaline complexes, Cambrian to Precambrian granite gneisses, Permo-Triassic sandstones and coal, and Recent to Tertiary surficial formations. South Africa's uranium resources were reassessed during 1983 and the total recoverable resources in the Reasonably Assured and Estimated Additional Resource categories recoverable at less than $130/kg U were estimated to be 460 000 t U. This represents a decrease of 13,4% when compared with the 1981 assessment. South Africa's uranium production for 1983 amounted to 6 060 t U, a 4,21 % increase over the 1982 production of 5 816 t U. Ninety-seven percent of the production is derived from the Witwatersrand quartz-pebble conglomerates, the rest being produced as a by-product of copper mining at Palabora. South Africa maintained its position as a major low-cost uranium producer, holding 14% of the WOCA uranium resources, and during 1982 it produced 14% of WOCA's uranium. In making future production capability projections it may be safely concluded that South Africa would be able to produce uranium at substantial levels well into the next century

  12. Unearthing a hidden treasure: 60 years of karst research in the Far West Rand, South Africa

    Directory of Open Access Journals (Sweden)

    Aljoscha Schrader

    2015-05-01

    Full Text Available Karstified dolomitic formations situated in the Far West Rand goldfield of the Witwatersrand Basin constitute a significant groundwater resource in semi?arid South Africa and would be of strategic importance for alleviating the increasing water stress in nearby metropolitan areas. The deep?level gold mines operating below the dolomites have suffered from large volumes of dolomitic groundwater flowing into the mine voids, rendering mining both expensive and hazardous. In order to secure safe and economical mining, the overlying dolomites were dewatered. Here we review research over 60 years, conducted in three of the four major dolomitic compartments affected by dewatering. After more than six decades of research, these aquifers are arguably the most investigated karst systems in South Africa, and possibly worldwide. The data generated are, in many respects, unique, as many measurements can never be repeated, covering stochastic events such as a major water inrush into mine workings and some of the most catastrophic sinkhole developments ever recorded. Given the potential value for improving the understanding of general and local karst hydrogeology, our main goal for this paper is to alert the scientific community to the existence of this resource of mostly unpublished data and research. A no less important aim is to support a systematic collation of these studies which are in danger of being irretrievably lost as mines increasingly close down. Ecological and economic impacts of the flooding of mines in and around Johannesburg emphasise the lack of reliable historical mine data to optimally address the matter. We provide the first comprehensive, yet not exhaustive, overview on the existing studies, briefly discussing scientific content as well as obstacles for utilising the scattered, and often non?peer reviewed, information sources.

  13. Genesis of uranium-gold pyritic conglomerates

    International Nuclear Information System (INIS)

    Myers, W.B.

    1981-01-01

    The ancient pyritic ore conglomerates have a common origin best exemplified by the Witwatersrand deposits. All contain detrital pyrite and uraninite, which are unstable in modern oxygenated environments and were deposited in a reducing atmosphere. The Rand reefs are not similar to modern gold placers. Placers result from the near incapacity of streams and currents to transport coarse gold. Placers as rich as Rand reef occur only in narrow paystreaks within 15 kilometers of a coarse-gold source. The board dispersion of gold in the reefs is due to solution transport of metal complexed as aurous sulfide, leached anoxygenically from crustal rocks, probably from sea-floor basalt, and precipitated by a slow reaction driven by the radioactive decay of detrital uraninite. Radiolysis of water on shallow marine unconformities resulted in diffusion of hydrogen to the atmosphere and a slight excess of hydroxyl free radical in the reef environment. The mild oxidizing tendency slowly dissolved uranium, precipitated gold, and oxygenated thucholite. These actions define a maturing process. A uraninite placer accumulating on an unconformity becomes progressively converted to a gold reef with little residual uraninite. The most mature reefs tend to grade toward the thucholite-seam type, very thin but exceedingly rich in gold. A combination of chemical attack and physical reworking accounts for the general thinness of mature reefs. Pyrite, like uraninite, decreases in abundance with increasing maturity; buffering by pyrite moderated the oxidative depletion of uranium. Where pyrite was scanty or absent, uraninite was completely dissolved by the effects of radiolysis and no ore formed

  14. Socioeconomic differences in mortality in the antiretroviral therapy era in Agincourt, rural South Africa, 2001-13: a population surveillance analysis.

    Science.gov (United States)

    Kabudula, Chodziwadziwa W; Houle, Brian; Collinson, Mark A; Kahn, Kathleen; Gómez-Olivé, Francesc Xavier; Tollman, Stephen; Clark, Samuel J

    2017-09-01

    Understanding the effects of socioeconomic disparities in health outcomes is important to implement specific preventive actions. We assessed socioeconomic disparities in mortality indicators in a rural South African population over the period 2001-13. We used data from 21 villages of the Agincourt Health and socio-Demographic Surveillance System (HDSS). We calculated the probabilities of death from birth to age 5 years and from age 15 to 60 years, life expectancy at birth, and cause-specific and age-specific mortality by sex (not in children mortality was 9·8 deaths per 1000 person-years. We found significant socioecomonic status gradients for mortality and life expectancy at birth, with outcomes improving with increasing socioeconomic status. An inverse relation was seen for HIV/AIDS and tuberculosis mortality and socioeconomic status that persisted from 2001 to 2013. Deaths from non-communicable diseases increased over time in both sexes, and injury was an important cause of death in men and boys. Neither of these causes of death, however, showed consistent significant associations with household socioeconomic status. The poorest people in the population continue to bear a high burden of HIV/AIDS and tuberculosis mortality, despite free antiretroviral therapy being made available from public health facilities. Associations between socioeconomic status and increasing burden of mortality from non-communicable diseases is likely to become prominent. Integrated strategies are needed to improve access to and uptake of HIV testing, care, and treatment, and management of non-communicable diseases in the poorest populations. Wellcome Trust, South African Medical Research Council, and University of the Witwatersrand, South Africa. Copyright © 2017 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.

  15. Precambrian uranium-bearing quartz-pebble conglomerates: exploration model and United States resource potential

    International Nuclear Information System (INIS)

    Houston, R.S.; Karlstrom, K.E.

    1979-11-01

    Uranium has been discovered in fluvial quartz-pebble conglomerates in most of the Precambrian shield areas of the world, including the Canadian, African, South American, Indian, Baltic, and Australian shields. Occurrences in these and other areas are shown. Two of these occurrences, the Huronian supergroup of Canada and the Witwatersrand deposit of South Africa contain 20 to 30 percent of the planet's known uranium reserves. Thus it is critical that we understand the origin of these deposits and develop exploration models that can aid in finding new deposits. Inasmuch as these uranium-bearing conglomerates are confined almost entirely to rocks of Precambrian age, Part I of this review begins with a discussion of Precambrian geology as it applies to the conglomerates. This is followed by a discussion of genetic concepts, a discussion of unresolved problems, and finally a suggested exploration model. Part II summarizes known and potential occurrences of Precambrian fossil placers in the world and evaluates them in terms of the suggested exploration model. Part III discusses the potential for important Precambrian fossil-placer uranium deposits in the United States and includes suggestions that may be helpful in establishing an exploration program in this country. Part III also brings together new (1975-1978) data on uranium occurrences in the Precambrian of the Wyoming Province. Part IV is a complete bibliography of Precambrian fossil placers, divided according to geographical areas. In total, this paper is designed to be a comprehensive review of Precambrian uranium-bearing fossil placers which will be of use to uranium explorationists and to students of Precambrian geology

  16. Can the anti-inflammatory activities of β2-agonists be harnessed in the clinical setting?

    Directory of Open Access Journals (Sweden)

    Theron AJ

    2013-11-01

    Full Text Available Annette J Theron,1,2 Helen C Steel,1 Gregory R Tintinger,1 Charles Feldman,3 Ronald Anderson1 1Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria, 2Tshwane Academic Division of the National Health Laboratory Service, Pretoria, 3Division of Pulmonology, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand and Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa Abstract: Beta2-adrenoreceptor agonists (β2-agonists are primarily bronchodilators, targeting airway smooth muscle and providing critical symptomatic relief in conditions such as bronchial asthma and chronic obstructive pulmonary disease. These agents also possess broad-spectrum, secondary, anti-inflammatory properties. These are mediated largely, though not exclusively, via interactions with adenylyl cyclase-coupled β2-adrenoreceptors on a range of immune and inflammatory cells involved in the immunopathogenesis of acute and chronic inflammatory disorders of the airways. The clinical relevance of the anti-inflammatory actions of β2-agonists, although often effective in the experimental setting, remains contentious. The primary objectives of the current review are: firstly, to assess the mechanisms, both molecular and cell-associated, that may limit the anti-inflammatory efficacy of β2-agonists; secondly, to evaluate pharmacological strategies, several of which are recent and innovative, that may overcome these limitations. These are preceded by a consideration of the various types of β2-agonists, their clinical applications, and spectrum of anti-inflammatory activities, particularly those involving adenosine 3',5'-cyclic adenosine monophosphate-activated protein kinase-mediated clearance of cytosolic calcium, and altered gene expression in immune and inflammatory cells. Keywords: adenylyl cyclase, corticosteroids, cyclic AMP, muscarinic

  17. Social Justice and Environmental Awareness Developed through a Citizens' Jury

    Science.gov (United States)

    Knight, J.

    2014-12-01

    A Citizens' Jury (CJ) is a discussion forum in which managers, policymakers or politicians are able to present their case to the general public ('citizens') to whom they are accountable, and for these citizens to critically ask questions of the managers/policymakers/politicians in order to better understand issues surrounding local development, planning and policy, impacts and adaptive measures, and to highlight their concerns. A CJ can be useful with respect to developing social justice and environmental awareness issues because it can empower community action and present different viewpoints. A practical CJ exercise is used in a second-year undergraduate course entitled Climate Change and Society, at University of the Witwatersrand, Johannesburg, South Africa. The CJ is used to consider some of the impacts of management policies used for climate change and sustainable development adaption, based on a hypothetical scenario. This scenario is that a major energy company wants to build a dam with hydroelectric power station in a developing country. This will provide low-carbon renewable energy to the country, investment in electricity infrastructure, and the company is committed to help economic development in the country, including in jobs and education. However, building and flooding of the dam will involve displacing 10,000 people from rural communities, flooding agricultural areas and areas of high biodiversity, and archaeological sites. The exercise is based on students, in groups, assuming different 'identities' which may include a local business person, resident, politician, member of an NGO, tourist, engineer, farmer etc, from which viewpoint they must argue for/against the proposal and to question other peoples' viewpoints. This exercise is useful because it allows students to develop understandings of different viewpoints, evaluate risk and impacts on different communities, and highlights the complexity of real-world decision-making.

  18. The Search for Life on Mars - Current Knowledge, Earth Analogues, and Principal Issues

    Science.gov (United States)

    Mumma, Michael J.

    2012-01-01

    For centuries, the planet Mars has been imagined as a possible abode for life. Serious searches for life's signatures began in the 19th century via ground-based visual astronomy that stimulated a vibrant fantasy literature but little lasting scientific knowledge. Modern scientific inquiry has emphasized the search for chemical signatures of life in the soil and rocks at the planet's surface, and via biomarker gases in the atmosphere. Today, investigations are based on high-resolution spectroscopy at Earth's largest telescopes along with planet orbiting and landed space missions. Methane has assumed central importance in these searches. Living systems produce more than 900/0 of Earth's atmospheric methane; the balance is of geochemical origin. Abundant methane is not expected in an oxidizing atmosphere such as Mars', and its presence would imply recent release - whether biological or geochemical. F or that reason, the quest for methane on Mars has been a continuing thread in the fabric of searches conducted since 1969. I will review aspects of the discovery and distribution of methane on Mars, and will mention ongoing extended searches for clues to its origin and destruction. On Earth, hydrogen (generated via serpentinization or radiolysis of water) provides an important 'fuel' for carbonate-reducing and sulphate-reducing biota (CH4 and H2S producers, respectively). Several such communities are known to reside at depth in continental domains (e.g., Lidy Hot Springs, Idaho; Witwatersrand Basin, S. Africa). If similar conditions exist in favourable locations on Mars, organisms similar to these could likely prosper there. Geologic (abiotic) production will also be mentioned, especially abiotic methane production associated with low-temperature serpentinization (e.g., terrestrial ophiolites). It is vitally important to pursue evidence for geochemical and biological production with equal vigour and intellectual weight lest unwanted and unintended bias contaminate the

  19. Using exploratory factor analysis in personality research: Best-practice recommendations

    Directory of Open Access Journals (Sweden)

    Sumaya Laher

    2010-11-01

    Research purpose: This article presents more objective methods to determine the number of factors, most notably parallel analysis and Velicer’s minimum average partial (MAP. The benefits of rotation are also discussed. The article argues for more consistent use of Procrustes rotation and congruence coefficients in factor analytic studies. Motivation for the study: Exploratory factor analysis is often criticised for not being rigorous and objective enough in terms of the methods used to determine the number of factors, the rotations to be used and ultimately the validity of the factor structure. Research design, approach and method: The article adopts a theoretical stance to discuss the best-practice recommendations for factor analytic research in the field of psychology. Following this, an example located within personality assessment and using the NEO-PI-R specifically is presented. A total of 425 students at the University of the Witwatersrand completed the NEO-PI-R. These responses were subjected to a principal components analysis using varimax rotation. The rotated solution was subjected to a Procrustes rotation with Costa and McCrae’s (1992 matrix as the target matrix. Congruence coefficients were also computed. Main findings: The example indicates the use of the methods recommended in the article and demonstrates an objective way of determining the number of factors. It also provides an example of Procrustes rotation with coefficients of agreement as an indication of how factor analytic results may be presented more rigorously in local research. Practical/managerial implications: It is hoped that the recommendations in this article will have best-practice implications for both researchers and practitioners in the field who employ factor analysis regularly. Contribution/value-add: This article will prove useful to all researchers employing factor analysis and has the potential to set the trend for better use of factor analysis in the South African context.

  20. Radon generation and transport in and around a gold mine tailings dam in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Speelman, W.J.; Lindsay, R. [Western Cape Univ., Dept. of Physics (South Africa); Newman, R.T. [IThemba LABS, Somerset West (South Africa); Meijer, R.J. de [Nuclear Geophysics Division (NGD), KVI, Rijksuniversiteit Groningen (Netherlands)

    2006-07-01

    Naturally Occurring Radioactive Material (N.O.R.M.) occurs in most soil and rock, and by mining and mineral processing, some of the radionuclides are significantly enhanced. An in-situ gamma-ray detector called M.E.D.U.S.A., has been used to produce a map of relative activity concentrations in a gold mine tailings dam on the Witwatersrand in South Africa. A CsI(Na) scintillation detector is used in this system. M.E.D.U.S.A. spectra obtained from the survey were analyzed using the Full-Spectrum Analysis (F.S.A.) procedure to compute the {sup 40}K, {sup 238}U and {sup 232}Th activity concentrations. The activity concentrations are used with global positioning data (G.P.S.) to produce the concentration maps. A hyper-pure germanium gamma-ray detector (Hp Ge) was used to measure gamma-rays from the naturally occurring nuclides for soil samples taken at different points on the site to calibrate the M.E.D.U.S.A. system. Radon soil gas measurements were performed at certain points on the mine tailings with a continuous radon monitor; R.A.D.7, and emanation coefficients were measured with electret technology. These parameters have been combined with the activity concentrations to obtain an average radon exhalation rate of about 0.1 Bq.m{sup -2}.s{sup -1} (with an uncertainty of about 20%) from the tailings dam. The purpose of the study is to also review and develop a mathematical model for radon activity concentration predictions in gold mine dumps. (authors)

  1. Economic evaluation of a shortened standardised treatment regimen of antituberculosis drugs for patients with multidrug-resistant tuberculosis (STREAM): study protocol.

    Science.gov (United States)

    Gama, Elvis; Madan, Jason; Langley, Ivor; Girma, Mamo; Evans, Denise; Rosen, Sydney; Squire, S Bertel

    2016-10-17

    Multidrug-resistant tuberculosis (MDR-TB) poses a serious financial challenge to health systems and patients. The current treatment for patients with MDR-TB takes up to 24 months to complete. Evidence for a shorter regimen which differs from the standard WHO recommended MDR-TB regimen and typically lasts between 9 and 12 months has been reported from Bangladesh. This evaluation aims to assess the economic impact of a shortened regimen on patients and health systems. This evaluation is innovative as it combines patient and health system costs, as well as operational modelling in assessing the impact. An economic evaluation nested in a clinical trial with 2 arms will be performed at 4 facilities. The primary outcome measure is incremental cost to the health system of the study regimen compared with the control regimen. Secondary outcome measures are mean incremental costs incurred by patients by treatment outcome; patient costs by category (direct medical costs, transport, food and accommodation costs, and cost of guardians/accompanying persons and lost time); health systems cost by category and drugs; and costs related to serious adverse events. The study has been evaluated and approved by the Ethics Advisory Group of the International Union Against Tuberculosis and Lung Disease; South African Medical Research Ethics Committee; Wits Health Consortium Protocol Review Committee; University of the Witwatersrand Human Research Ethics Committee; University of Kwazulu-Natal Biomedical Research Ethics Committee; St Peter TB Specialized Hospital Ethical Review Committee; AHRI-ALERT Ethical Review Committee, and all participants will provide written informed consent. The results of the economic evaluation will be published in a peer-reviewed journal. ISRCTN78372190. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  2. Increasing diversity in the geosciences through the AfricaArray geophysics field course

    Science.gov (United States)

    Vallejo, G.; Emry, E.; Galindo, B. L.; Carranza, V.; Gomez, C. D.; Ortiz, K.; Castro, J. G.; Guandique, J.; Falzone, C.; Webb, S. J.; Manzi, M.; Mngadi, S. B.; Stephens, K.; Chinamora, B.; Whitehead, R.; de Villiers, D. P.; Tshitlho, K.; Delhaye, R. P.; Smith, J. A.; Nyblade, A.

    2014-12-01

    For the past nine years, the AfricaArray diversity program, sponsored by industry, the National Science Foundation, and several partnering universities have supported outstanding U.S. STEM underrepresented minority undergraduates to gain field experience in near-surface geophysical techniques during an 8-week summer program at Penn State University and the University of Witwatersrand (Wits). The AfricaArray geophysics field school, which is run by Wits, has been teaching field-based geophysics to African students for over a decade. In the first 2-3 weeks of the program, the U.S. students are given basic instruction in near-surface geophysics, South African geology, and South African history and culture. The students then join the Wits AfricaArray geophysics field school - working alongside Wits students and students from several other African universities to map the shallow subsurface in prospective areas of South Africa for platinum mining. In addition to the primary goals of collecting and interpreting gravity, magnetic, resistivity, seismic refraction, seismic reflection, and EM data, students spend time mapping geologic units and gathering information on the physical properties of the rocks in the region (i.e. seismic velocity, density, and magnetic susceptibility). Subsurface targets include mafic dikes, faults, the water table, and overburden thickness. Upon returning to the U.S., students spend 2-3 weeks finalizing their project reports and presentations. The program has been effective at not only providing students with fundamental skills in applied geophysics, but also in fostering multicultural relationships, preparing students for graduate work in the geosciences, and attracting STEM students into the geosciences. Student presenters will discuss their experiences gained through the field school and give their impressions about how the program works towards the goal of increasing diversity in the geosciences in the U.S.

  3. Shear Wave Velocity Structure of Southern African Crust: Evidence for Compositional Heterogeneity within Archaean and Proterozoic Terrains

    Energy Technology Data Exchange (ETDEWEB)

    Kgaswane, E M; Nyblade, A A; Julia, J; Dirks, P H H M; Durrheim, R J; Pasyanos, M E

    2008-11-11

    Crustal structure in southern Africa has been investigated by jointly inverting receiver functions and Rayleigh wave group velocities for 89 broadband seismic stations spanning much of the Precambrian shield of southern Africa. 1-D shear wave velocity profiles obtained from the inversion yield Moho depths that are similar to those reported in previous studies and show considerable variability in the shear wave velocity structure of the lower part of the crust between some terrains. For many of the Archaean and Proterozoic terrains in the shield, S velocities reach 4.0 km/s or higher over a substantial part of the lower crust. However, for most of the Kimberley terrain and adjacent parts of the Kheis Province and Witwatersrand terrain, as well as for the western part of the Tokwe terrain, mean shear wave velocities of {le} 3.9 km/s characterize the lower part of the crust along with slightly ({approx}5 km) thinner crust. These findings indicate that the lower crust across much of the shield has a predominantly mafic composition, except for the southwest portion of the Kaapvaal Craton and western portion of the Zimbabwe Craton, where the lower crust is intermediate-to-felsic in composition. The parts of the Kaapvaal Craton underlain by intermediate-to-felsic lower crust coincide with regions where Ventersdorp rocks have been preserved, and thus we suggest that the intermediate-to-felsic composition of the lower crust and the shallower Moho may have resulted from crustal melting during the Ventersdorp tectonomagmatic event at c. 2.7 Ga and concomitant crustal thinning caused by rifting.

  4. Preconcentration of low grade uranium ores by gravity and magnetic methods: a case study with copper tailings from Singhbhum, Bihar, India

    International Nuclear Information System (INIS)

    Natarajan, R.; Sreenivas, T.; Krishna Rao, N.

    1992-01-01

    The physical beneficiation methods applied to uranium ores are gravity and magnetic techniques. Feasibility of application of these two techniques has been industrially demonstrated in the case of Palabora copper-uranium ores and Witwatersrand gold-uranium ores respectively. In India exhaustive studies have been carried out on the application of gravity and magnetic methods for preconcentration of uranium values from tailings of copper plants at Surda, Rakha and Mosabani in Singhbhum. While recovery by shaking tables is poor owing to non-liberation and inefficient recovery in finer particle sizes (-37μm), gravity machines like Bartles Mozely Separator and Bartles Cross Belt Concentrator are able to give improved recovery in sizes down to about 15μm. Application of Wet High Intensity Magnetic Separator (WHIMS) is able to improve the recovery to about 75 to 85% from the three tailings, and the improvement is due to the ability of WHIMS collect the micaceous mineral particles containing composite uranium values, as well as uraninite particles down to about 10μm in size. WHIMS is inefficient in recovering uraninite particles below 5μm. High Gradient Magnetic Separator and Super Conducting High Gradient Magnetic Separator, on the other hand, are able to give enhanced recovery of even < 5μm uraninite particles. With the improved technology of gravity and magnetic methods now available, it should now be techno-economically feasible to employ preconcentration of low tenor uranium ores by physical beneficiation, prior to chemical processing. (author). 25 refs. 8 figs, 5 tabs

  5. The ATLAS experience and its relevance to the data acquisition of the BM@N experiment at the NICA complex

    International Nuclear Information System (INIS)

    Tomiwa, K G; Mellado, B; Slepnev, I; Bazylev, S

    2016-01-01

    The quest to understand the world around us has increased the size of high energy physics experiments and the processing rate of the data output from high energy experiments. The Large Hadron Collider is the largest experimental set-up known, with ATLAS detector as one of the detectors built to record proton-proton collision at about 10 PB/s (Petabit/s) around the LHC interaction point. With the Phase-II upgrade in 2022 this data output will increase by at least 10 times higher than those of today due to luminosity increase, this poses a serious challenge on processing and storage of the data. Also the BM@N fixed target experiment is expected to have event size of about 80,000 bytes/Event, leading to huge amount of data output to be processed in real time. Experimentalists handle these challenges by developing High-throughput electronic, with the capability of processing and reducing big data to scientific data in real time. One of these high-throughput electronics is the Super Readout Driver (sROD) and ARM-based processing unit (PU) developed for ATLAS TileCal detector by the University of the Witwatersrand. The sROD is designed to process data from Tile Calorimeter at 40 MHz. This work takes a look at the architecture of the data acquisition (DAQ) system of the BM@N detectors and the adaptation of the high-throughput systems to last stage of the BM@N DAQ system. (paper)

  6. Teleducation : Linking Continents Across Time and Space Through Live, Real-Time Interactive Classes

    Science.gov (United States)

    Macko, S. A.; Szuba, T.; Swap, R.; Annegarn, H.; Marjanovic, B.; Vieira, F.; Brito, R.

    2005-12-01

    International education is a natural extension of global economies, global environmental concerns, and global science. While faculty and student exchanges between geographic areas permit for educational experiences and cultural exchanges for the privileged few, distance learning offers opportunities for educational exchanges under any circumstance where time, expense, or location otherwise inhibit offering or taking a particular course of study. However, there are severe pedagogical limitations to traditional Web-based courses that suffer from a lack of personalized, spontaneous exchange between instructor and student. The technology to establish a real time, interactive teleducation program exists, but to our knowledge is relatively untested in a science classroom situation, especially internationally over great distances. In a project to evaluate this type of linkage, we offered a real-time, interactive class at three separate universities, which communicated instantaneously across an ocean at a distance of greater than 8,000 miles and seven time zones. The course, 'Seminar on the Ecology of African Savannas', consisted of a series of 11 lectures originating in either Mozambique (University of Eduardo Mondlane), South Africa (University of the Witwatersrand) or the United States (University of Virginia). We combined ISDN, internet and satellite linkages to facilitate the lectures and real time discussions between instructors and approximately 200 university students in the three countries. Although numerous technical, logistical, and pedagogical issues - both expected and unexpected - arose throughout the pilot year, the project can be viewed as overwhelmingly successful and certainly serves as proof-of-concept for future initiatives, both internationally and locally. This review of our experience will help to prepare other students, faculty, and institutions interested in establishing or developing international education initiatives

  7. Precambrian uranium-bearing quartz-pebble conglomerates: exploration model and United States resource potential

    Energy Technology Data Exchange (ETDEWEB)

    Houston, R.S.; Karlstrom, K.E.

    1979-11-01

    Uranium has been discovered in fluvial quartz-pebble conglomerates in most of the Precambrian shield areas of the world, including the Canadian, African, South American, Indian, Baltic, and Australian shields. Occurrences in these and other areas are shown. Two of these occurrences, the Huronian supergroup of Canada and the Witwatersrand deposit of South Africa contain 20 to 30 percent of the planet's known uranium reserves. Thus it is critical that we understand the origin of these deposits and develop exploration models that can aid in finding new deposits. Inasmuch as these uranium-bearing conglomerates are confined almost entirely to rocks of Precambrian age, Part I of this review begins with a discussion of Precambrian geology as it applies to the conglomerates. This is followed by a discussion of genetic concepts, a discussion of unresolved problems, and finally a suggested exploration model. Part II summarizes known and potential occurrences of Precambrian fossil placers in the world and evaluates them in terms of the suggested exploration model. Part III discusses the potential for important Precambrian fossil-placer uranium deposits in the United States and includes suggestions that may be helpful in establishing an exploration program in this country. Part III also brings together new (1975-1978) data on uranium occurrences in the Precambrian of the Wyoming Province. Part IV is a complete bibliography of Precambrian fossil placers, divided according to geographical areas. In total, this paper is designed to be a comprehensive review of Precambrian uranium-bearing fossil placers which will be of use to uranium explorationists and to students of Precambrian geology.

  8. Balinsky’s Darwinian roots

    Directory of Open Access Journals (Sweden)

    B. Fabian

    2010-02-01

    Full Text Available Boris Ivan Balinsky (1905–1997 was Professor and Head of the Department of Zoology at the University of the Witwatersrand (Wits,Johannesburg,South Africa. He came to Wits in 1949 (via Munich and Edinburghfrom Kiev,where he was Professor of Embryology. As an acclaimed experimental embryologist he was especially famous for inducing a supernumerary limb in a newt when he was a19-year-old student in Ivan Schmalhausen’s laboratory in Kiev 1924. In Johannesburg he wrote his famous text book of embryology, which influenced generations of students around the world.In addition to pioneering the application of electronmicros-copy to the study of early development, he tackled a variety of projects of general zoological interest. Lesser known is his latter daywork, carried out during his retirement, on variation and hereditability (especially of wing colourationin the butterfly Acraeahorta, on which he published five papers from 1974 to 1986. His butterfly work showing the loose connection between the genotype and phenotype, with the genotype expressing itself in a variable way in the face of a constant physical environment,is of special interest in the current era of evolutionary and ecological developmental biology. His exposure to the stimulating evolutionary ideas of Schmalhausen during his early Kiev years no doubt provided a context for his butterfly work.Some ideas about how the ‘loose connection between the genotype and phenotype’maybe achieved through behavioral modification or positional information during development are addressed in this paper in the light of recent work.In his eighties Balinsky worked on the classification of microlepidoptera on which he published several papers. He died in September 1997, just short of his 92nd birthday.

  9. A review of accounting research in internationalising journals in the South African region

    Directory of Open Access Journals (Sweden)

    Charl J. de Villiers

    2017-12-01

    Witwatersrand, being prominent. Large proportions of authors of 2015–2016 articles are from outside of Africa, speaking to the success of the internationalisation efforts of the internationalising journals, whereas SAJAR mostly publishes articles by African authors.

  10. Simplified clinical algorithm for identifying patients eligible for immediate initiation of antiretroviral therapy for HIV (SLATE): protocol for a randomised evaluation.

    Science.gov (United States)

    Rosen, Sydney; Fox, Matthew P; Larson, Bruce A; Brennan, Alana T; Maskew, Mhairi; Tsikhutsu, Isaac; Bii, Margaret; Ehrenkranz, Peter D; Venter, Wd Francois

    2017-05-28

    African countries are rapidly adopting guidelines to offer antiretroviral therapy (ART) to all HIV-infected individuals, regardless of CD4 count. For this policy of 'treat all' to succeed, millions of new patients must be initiated on ART as efficiently as possible. Studies have documented high losses of treatment-eligible patients from care before they receive their first dose of antiretrovirals (ARVs), due in part to a cumbersome, resource-intensive process for treatment initiation, requiring multiple clinic visits over a several-week period. The Simplified Algorithm for Treatment Eligibility (SLATE) study is an individually randomised evaluation of a simplified clinical algorithm for clinicians to reliably determine a patient's eligibility for immediate ART initiation without waiting for laboratory results or additional clinic visits. SLATE will enrol and randomise (1:1) 960 adult, HIV-positive patients who present for HIV testing or care and are not yet on ART in South Africa and Kenya. Patients randomised to the standard arm will receive routine, standard of care ART initiation from clinic staff. Patients randomised to the intervention arm will be administered a symptom report, medical history, brief physical exam and readiness assessment. Patients who have positive (satisfactory) results for all four components of SLATE will be dispensed ARVs immediately, at the same clinic visit. Patients who have any negative results will be referred for further clinical investigation, counselling, tests or other services prior to being dispensed ARVs. After the initial visit, follow-up will be by passive medical record review. The primary outcomes will be ART initiation ≤28 days and retention in care 8 months after study enrolment. Ethics approval has been provided by the Boston University Institutional Review Board, the University of the Witwatersrand Human Research Ethics Committee (Medical) and the KEMRI Scientific and Ethics Review Unit. Results will be published in

  11. Origins and ages of fracture fluids in the South African Crust

    Science.gov (United States)

    Heard, A. W.; Warr, O.; Borgonie, G.; Linage-Alvarez, B.; Kuloyo, O.; Magnabosco, C.; Lau, M.; Erasmus, M.; Cason, E. D.; van Heerden, E.; Kieft, T. L.; Mabry, J.; Onstott, T. C.; Sherwood Lollar, B.; Ballentine, C. J.

    2017-12-01

    Crustal fracture fluids can remain isolated for millions (Myr) to billions of years (Gyr), and contain information on paleohydrogeology, subsurface ecology, and conservative components that may elucidate the atmospheric evolution of the early Earth [1-3]. Stable isotope analyses of water combined with isotopic analyses of the dissolved noble gases provide insight into the history of aqueous fracture fluids. We report stable isotope and noble gas data for fracture fluids from 5 different sites in the Witwatersrand Basin and Bushveld Igneous Province, South Africa. We determine radiogenic noble gas residence times ranging from thousands of years to tens of millions of years. The oldest sample, from Masimong Mine, has a water stable isotopic composition close to the global meteoric water line (GMWL), indicating its preservation in the crust and making it one of the oldest recorded paleometeoric waters. The δ2H and δ18O of water in this sample and similar age samples from the same mining district [1,4] require isotopically depleted groundwater recharge compared to modern precipitation. This could reflect a recharge regime at a higher paleolatitude, elevation, or with higher rainfall, established up to tens of Myr ago, and perhaps similar to the recharge regime in the modern Lesotho Highlands [5]. These data suggest that groundwater isotopes may provide useful paleoclimatic information for many Myr. As hypothesized, such paleometeoric water samples lack 124-128Xe enrichments reported from Gyr age groundwaters discovered on the Canadian Shield [3] and in Archean fluid inclusions [6], providing an important control set and reaffirming that those samples record the evolution of ancient atmospheric Xe rather than subsurface alteration. [1] Lippmann, J. et al. (2003) GCA 67, 4597-4619. [2] Lin, L.-H. (2006) et al. Science 314, 479-482. [3] Holland, G. et al. (2013) Nature 497, 357-360. [4] Lippmann-Pipke, J. et al. (2011) Chem. Geol. 283, 287-296. [5] West, A. G. et al

  12. Economic and organizational sustainability of a negative-pressure portable device for the prevention of surgical-site complications

    Directory of Open Access Journals (Sweden)

    Foglia E

    2017-06-01

    Full Text Available Emanuela Foglia,1 Lucrezia Ferrario,1 Elisabetta Garagiola,1 Giuseppe Signoriello,2 Gianluca Pellino,3 Davide Croce,1,4 Silvestro Canonico3 1Centre for Health Economics, Social and Health Care Management - LIUC University, Castellanza, Italy; 2Department of Mental Health and Preventive Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy; 3School of Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy; 4School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South \tAfrica Purpose: Surgical-site complications (SSCs affect patients’ clinical pathway, prolonging their hospitalization and incrementing their management costs. The present study aimed to assess the economic and organizational implications of a portable device for negative-pressure wound therapy (NPWT implementation, compared with the administration of pharmacological therapies alone for preventing surgical complications in patients undergoing general, cardiac, obstetrical–gynecological, or orthopedic surgical procedures.Patients and methods: A total of 8,566 hospital procedures, related to the year 2015 from one hospital, were evaluated considering infection risk index, occurrence rates of SSCs, drug therapies, and surgical, diagnostic, and specialist procedures and hematological exams. Activity-based costing and budget impact analyses were implemented for the economic assessment.Results: Patients developing an SSC absorbed i 64.27% more economic resources considering the length of stay (€ 8,269±2,096 versus € 5,034±2,901, p<0.05 and ii 42.43% more economic resources related to hematological and diagnostic procedures (€ 639±117 versus € 449±72, p<0.05. If the innovative device had been used over the 12-month time period, it would have decreased the risk of developing SSCs; the hospital would have realized an average reduction in health care expenditure equal to −0.69% (−€ 483

  13. Investor's and procurement guide South Africa. Pt. 1. Heavy minerals, rare earth elements, antimony

    Energy Technology Data Exchange (ETDEWEB)

    Graupner, Torsten; Schwarz-Schampera, Ulrich [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Berlin (Germany); Hammond, Napoleon Q.; Opperman, Rehan; Long' a Tongu, Elisa; Kenan, Abdul O.; Nondula, Unathi; Tsanwani, Matamba [Council for Geoscience (CGS), Pretoria (South Africa). Dept. of Mineral Resources Development; Liedke, Maren; Marbler, Herwig [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Berlin (Germany). Deutsche Rohstoffagentur (DERA)

    2014-03-15

    This is the first part of the ''Investor's and Procurement Guide South Africa'', a handbook for investing and doing business in South Africa's mineral industry. It is anticipated that this publication will aid potential investors into considering South Africa as an investment destination, not only for raw materials, but also for related industries. This manual supplements the many publications available on the economic geology and mineral wealth in South Africa and has been designed to guide prospective and current investors, suppliers and mine equipment exporters through the process of doing business in Africa's biggest and dynamic economy. As well as detailing the mineral raw materials heavy minerals, rare-earth metals and antimony, the handbook provides a general introduction to South Africa and its infrastructure, the economical, political and judicial frame of the South African mining industry and an overview of the economic geology. South Africa has a long and complex geological history which dates back in excess of 3.6 billion years. The country has a vast mineral wealth, undoubtedly due to the fact that a significant proportion of the Archaean and younger rocks have been preserved. The mining of the enormous Witwatersrand gold deposits, commencing in 1886, has led to the establishment of South Africa's well-developed infrastructure and to the sustained growth of an industrial and service sector in the country. With the world's largest resources of PGMs, gold, chromite, vanadium and manganese and significant resources of iron, coal and numerous other minerals and metals, the minerals industry will continue to play a pivotal role in the growth of South Africa's economy in the foreseeable future. South Africa is one of the top destinations in Africa for foreign direct investments. South African headquartered companies have been major investors into foreign direct investments on the African continent in the past

  14. A prospective, observational study comparing the PK/PD relationships of generic Meropenem (Mercide® to the innovator brand in critically ill patients

    Directory of Open Access Journals (Sweden)

    Mer M

    2016-11-01

    Full Text Available Mervyn Mer,1 Jacques Rene Snyman,2 Constance Elizabeth Jansen van Rensburg,2 Jacob John van Tonder,3 Ilze Laurens2 1Department of Medicine, Divisions of Critical Care and Pulmonology, University of the Witwatersrand, Johannesburg, South Africa; 2Office of the Dean, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa; 3Scientific Affairs Department, Triclinium Clinical Development (Pty Ltd, Centurion, South Africa Introduction: Clinicians’ skepticism, fueled by evidence of inferiority of some multisource generic antimicrobial products, results in the underutilization of more cost-effective generics, especially in critically ill patients. The aim of this observational study was to demonstrate equivalence between the generic or comparator brand of meropenem (Mercide® and the leading innovator brand (Meronem® by means of an ex vivo technique whereby antimicrobial activity is used to estimate plasma concentration of the active moiety. Methods: Patients from different high care and intensive care units were recruited for observation when prescribed either of the meropenem brands under investigation. Blood samples were collected over 6 hours after a 30 minute infusion of the different brands. Meropenem concentration curves were established against United States Pharmacopeia standard meropenem (Sigma-Aldrich by using standard laboratory techniques for culture of Klebsiella pneumoniae. Patients’ plasma samples were tested ex vivo, using a disc diffusion assay, to confirm antimicrobial activity and estimate plasma concentrations of the two brands. Results: Both brands of meropenem demonstrated similar curves in donor plasma when concentrations in vials were confirmed. Patient-specific serum concentrations were determined from zones of inhibition against a standard laboratory Klebsiella strain ex vivo, confirming at least similar in vivo concentrations as the concentration curves (90% confidence interval overlapped; however

  15. Characterisation and modelling of mercury speciation in urban air affected by gold mining - assessment of bioavailability

    Directory of Open Access Journals (Sweden)

    Cukrowska E. M.

    2013-04-01

    Full Text Available The growing global concern over the release of mercury to the environment has prompted specific inventories that quantify mercury emissions from various sources. Investigations of atmospheric mercury have been mostly done on gaseous species. Although, to assess human expose to mercury, especially in urban areas, the inhalable dust should be included in a study. The Witwatersrand Basin in South Africa is one of the most important gold mining regions in the world. Mercury (Hg, which occurs in gold-bearing ores, was also used for gold recoveries in previous centuries (19th and early 20th century and presently in illegal artisanal mining. The consequences of these mining activities were the release of Hg to the environment, mainly due to AMD from tailings dumps which are presently reprocessed. The city of Johannesburg is a multimillion population exposed strongly to industrial pollution. The aim of this study was to determine the magnitude of mercury pollution in this urban area and assess its bioavailability. The gaseous samples were collected by trapping mercury on various gold traps. Dust samples were collected from a ground and on inhalation levels (1–2 m above a ground. They were later separated into different fractions by micro sieving. Bioavailability of mercury in inhalable dust (25 μm was tested by leaching collected samples with artificial lung fluid (ALF, pH 4.5, Gray’s solution (pH 7.4 and water. The leaching conditions were selected to mimic lungs environment (incubator at 30°C, time 24 hrs, rotation of samples 150 rpm. Total concentrations of mercury in dust fractions were also determined after microwave digestion. The results showed extremely high concentration levels of mercury in air and dust in industrial areas. Especially high levels were found around presently reprocessed old gold tailings dumps, up to 900 000 μgl–1. The levels dropped significantly in CBD area but still showing elevated concentrations up to 10 μgl−1

  16. Relationship between low-density lipoprotein cholesterol and severe acute pancreatitis (“the lipid paradox”

    Directory of Open Access Journals (Sweden)

    Hong W

    2018-05-01

    Full Text Available Wandong Hong,1,* Vincent Zimmer,2,3,* Simon Stock,4,* Maddalena Zippi,5 Jones AQ Omoshoro-Jones,6 Mengtao Zhou71Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China; 2Department of Medicine II, Saarland University Medical Center, Saarland University, Homburg, Germany; 3Department of Medicine, Marienhausklinik St Josef Kohlhof, Neunkirchen, Germany; 4Department of Surgery, World Mate Emergency Hospital, Battambang, Cambodia; 5Unit of Gastroenterology and Digestive Endoscopy, Sandro Pertini Hospital, Rome, Italy; 6Department of Surgery, Chris Hani-Baragwanath Academic Hospital, University of the Witwatersrand, Johannesburg, South Africa; 7Department of Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China*These authors contributed equally to this workBackground and aim: The aim of this study was to investigate the association between low-density lipoprotein cholesterol (LDL-C and the development of severe acute pancreatitis (SAP.Patients and methods: A total of 674 patients with acute pancreatitis were enrolled. Nonlinearity in the relationship between LDL-C and SAP was assessed by restricted cubic spline analysis. Univariable and multivariable regression analyses were used to identify independent risk factors of SAP.Results: The restricted cubic spline analysis suggested a nonlinear association between high-density lipoprotein cholesterol (HDL-C, LDL-C and triglyceride levels and incidence of SAP. The incidence of SAP in patients with low LDL-C (<90 mg/dL, moderate LDL-C (90–150 mg/dL and high LDL-C (>150 mg/dL levels was 15.1%, 3.7% and 9.8%, respectively. Multivariable analysis confirmed that low LDL-C levels (odds ratio [OR] 3.05; 95% confidence interval [CI] 1.35–6.90, high LDL-C levels (OR 4.42; 95% CI 1.41–13.87 and low HDL-C levels (OR 6.90; 95% CI 2.61–18.23 but

  17. Treating depression in HIV-positive patients affects adherence

    Directory of Open Access Journals (Sweden)

    M Y H Moosa

    2012-08-01

    Full Text Available Aim. To determine changes in adherence to antiretroviral therapy (ART in HIV-positive patients with depression, following treatment with an antidepressant or psychotherapy. Methods. The study was prospective, randomised and controlled. Consenting volunteers aged ≥18 years and stable on ART for ≥6 months were included in the study. Sociodemographic data were obtained, and a clinical diagnostic evaluation and the Hamilton Depression rating scale (HAMD were performed on all subjects at entry to and at the end of the study. Participants found to be depressed were randomly assigned antidepressant treatment (20 mg citalopram or interpersonal psychotherapy (IPT (5 sessions. Medication was dispensed at each visit and patients were asked to return all unused medication to determine ART adherence. The study was approved by the University of the Witwatersrand. Results. Sixty-two HIV-positive persons receiving ART participated; 30 were not depressed (control group and 32 were depressed (patient group. No significant differences in demographic characteristics existed between the control and patient groups. Mean ART adherence at the start of the study was 99.5% (standard error (SE ±0.46 and 92.1% (SE ±1.69 in the control and patients groups, respectively. Mean ART adherence at the end of the study changed marginally in the control group (99.7%; SE ±0.46 and increased significantly in the patient group (99.5%; SE± 0.13 (p>0.05. The mean ART adherence rate of patients who received pharmacotherapy increased from 92.8% to 99.5%, and of those who received psychotherapy increased from 91.1% to 99.6% (p>0.05. There was no significant association between the increased adherence in the patient group and baseline demographic and clinical characteristics, irrespective of antidepressant therapy or IPT (p>0.05. Conclusion. Successful treatment of depression with an antidepressant or psychotherapy was associated with improved ART adherence, independent of the type

  18. Alcohol use, antiretroviral therapy adherence, and preferences regarding an alcohol-focused adherence intervention in patients with human immunodeficiency virus

    Directory of Open Access Journals (Sweden)

    Kekwaletswe CT

    2014-03-01

    Full Text Available Connie T Kekwaletswe,1 Neo K Morojele1,21Alcohol and Drug Abuse Research Unit, Medical Research Council, Pretoria, 2School of Public Health, University of the Witwatersrand, Johannesburg, South AfricaBackground: The primary objectives of this study were to determine the association between alcohol and antiretroviral therapy (ART adherence and the perceived appropriateness and acceptability of elements of an adherence counseling program with a focus on alcohol-related ART nonadherence among a sample of ART recipients in human immunodeficiency virus (HIV clinics in Tshwane, South Africa.Methods: We conducted a cross-sectional study with purposive sampling. The sample comprised 304 male and female ART recipients at two President's Emergency Plan For AIDS Relief-supported HIV clinics. Using an interview schedule, we assessed patients' alcohol use (Alcohol Use Disorders Identification Test, other drug use, level of adherence to ART, and reasons for missing ART doses (AIDS Clinical Trials Group adherence instrument. Additionally, patients’ views were solicited on: the likely effectiveness of potential facilitators; the preferred quantity, duration, format, and setting of the sessions; the usefulness of having family members/friends attend sessions along with the patient; and potential skill sets to be imparted.Results: About half of the male drinkers’ and three quarters of the female drinkers’ Alcohol Use Disorders Identification Test scores were suggestive of hazardous or harmful drinking. Average self-reported ART adherence was 89.7%. There was a significant association between level of alcohol use and degree of ART adherence. Overall, participants perceived two clinic-based sessions, each of one hour’s duration, in a group format, and facilitated by a peer or adherence counselor, as most appropriate and acceptable. Participants also had a favorable attitude towards family and friends accompanying them to the sessions. They also favored an

  19. In vivo evaluation of a conjugated poly(lactide-ethylene glycol nanoparticle depot formulation for prolonged insulin delivery in the diabetic rabbit model

    Directory of Open Access Journals (Sweden)

    Tomar L

    2013-02-01

    Full Text Available Lomas Tomar,1,2 Charu Tyagi,1,3 Manoj Kumar,2 Pradeep Kumar,1 Harpal Singh,2 Yahya E Choonara,1 Viness Pillay11University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, Johannesburg, Gauteng, South Africa; 2Centre for Biomedical Engineering, Indian Institute of Technology, Delhi, India; 3VSPG College, Chaudhary Charan Singh University, Meerut, IndiaAbstract: Poly(ethylene glycol (PEG and polylactic acid (PLA-based copolymeric nanoparticles were synthesized and investigated as a carrier for prolonged delivery of insulin via the parenteral route. Insulin loading was simultaneously achieved with particle synthesis using a double emulsion solvent evaporation technique, and the effect of varied PEG chain lengths on particle size and insulin loading efficiency was determined. The synthesized copolymer and nanoparticles were analyzed by standard polymer characterization techniques of gel permeation chromatography, dynamic light scattering, nuclear magnetic resonance, and transmission electron microscopy. In vitro insulin release studies performed under simulated conditions provided a near zero-order release pattern up to 10 days. In vivo animal studies were undertaken with varied insulin loads of nanoparticles administered subcutaneously to fed diabetic rabbits and, of all doses administered, nanoparticles containing 50 IU of insulin load per kg body weight controlled the blood glucose level within the physiologically normal range of 90–140 mg/dL, and had a prolonged effect for more than 7 days. Histopathological evaluation of tissue samples from the site of injection showed no signs of inflammation or aggregation, and established the nontoxic nature of the prepared copolymeric nanoparticles. Further, the reaction profiles for PLA-COOH and NH2-PEGDA-NH2 were elucidated using molecular mechanics energy relationships in vacuum and in a solvated system by exploring the spatial disposition of various

  20. Knowledge, attitudes, practices and behaviors associated with female condoms in developing countries: a scoping review

    Directory of Open Access Journals (Sweden)

    Moore L

    2015-09-01

    Full Text Available Lizzie Moore,1 Mags Beksinska,1,2 Alnecia Rumphs,3 Mario Festin,4 Erica L Gollub3 1MatCH Research (Maternal, Adolescent and Child Health Research, Department of Obstetrics and Gynaecology, University of the Witwatersrand, Westville, Durban, South Africa; 2Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK; 3Florida International University, Department of Epidemiology, Stempel College of Public Health and Social Work, Miami, FL, USA; 4World Health Organization, Special Program of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland Abstract: Women in developing countries are at high risk of HIV, sexually transmitted infections, and unplanned pregnancy. The female condom (FC is an effective dual protective method regarded as a tool for woman's empowerment, yet supply and uptake are limited. Numerous individual, socioeconomic, and cultural factors influence uptake of new contraceptive methods. We reviewed studies of FC knowledge, attitudes, practices, and behaviors across developing countries, as well as available country-level survey data, in order to identify overarching trends and themes. High acceptability was documented in studies conducted in diverse settings among male and female FC users, with FCs frequently compared favorably to male condoms. Furthermore, FC introduction has been shown to increase the proportion of "protected" sex acts in study populations, by offering couples additional choice. However, available national survey data showed low uptake with no strong association with method awareness, as well as inconsistent patterns of use between countries. We identified a large number of method attributes and contextual factors influencing FC use/nonuse, most of which were perceived both positively and negatively by different groups and between settings. Male partner

  1. Sleep problems during the menopausal transition: prevalence, impact, and management challenges

    Directory of Open Access Journals (Sweden)

    Baker FC

    2018-02-01

    Full Text Available Fiona C Baker,1,2 Massimiliano de Zambotti,1 Ian M Colrain,1,3 Bei Bei4,5 1Center for Health Sciences, SRI International, Menlo Park, CA, USA; 2Brain Function Research Group, University of the Witwatersrand, Johannesburg, South Africa; 3Melbourne School of Psychological Sciences, University of Melbourne, 4Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, 5Centre for Women’s Mental Health, Department of Psychiatry, University of Melbourne, Royal Women’s Hospital, Melbourne, VIC, Australia Abstract: A substantial number of women experience sleep difficulties in the approach to menopause and beyond, with 26% experiencing severe symptoms that impact daytime functioning, qualifying them for a diagnosis of insomnia. Here, we review both self-report and polysomnographic evidence for sleep difficulties in the context of the menopausal transition, considering severity of sleep complaints and links between hot flashes (HFs and depression with poor sleep. Longitudinal population-based studies show that sleep difficulties are uniquely linked with menopausal stage and changes in follicle-stimulating hormone and estradiol, over and above the effects of age. A major contributor to sleep complaints in the context of the menopausal transition is HFs, and many, although not all, HFs are linked with polysomnographic-defined awakenings, with HF-associated wake time contributing significantly to overall wakefulness after sleep onset. Some sleep complaints may be comorbid with depressive disorders or attributed to sleep-related breathing or movement disorders, which increase in prevalence especially after menopause, and for some women, menopause, age, and environmental/behavioral factors may interact to disrupt sleep. Considering the unique and multifactorial basis for sleep difficulties in women transitioning menopause, we describe clinical assessment

  2. Maternal mortality in rural South Africa: the impact of case definition on levels and trends

    Directory of Open Access Journals (Sweden)

    Garenne M

    2013-08-01

    Full Text Available Michel Garenne,1–3 Kathleen Kahn,1,4,5 Mark A Collinson,1,4,5 F Xavier Gómez-Olivé,1,5 Stephen Tollman1,4,51MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 2Institut Pasteur, Epidémiologie des Maladies Emergentes, Paris, France; 3Institut de Recherche pour le Développement, UMI Résiliences, Centre Ile de France, Bondy, France; 4Centre for Global Health Research, Umeå University, Umeå, Sweden; 5INDEPTH Network, East Legon, Accra, GhanaBackground: Uncertainty in the levels of global maternal mortality reflects data deficiencies, as well as differences in methods and definitions. This study presents levels and trends in maternal mortality in Agincourt, a rural subdistrict of South Africa, under long-term health and sociodemographic surveillance.Methods: All deaths of women aged 15 years–49 years occurring in the study area between 1992 and 2010 were investigated, and causes of death were assessed by verbal autopsy. Two case definitions were used: “obstetrical” (direct causes, defined as deaths caused by conditions listed under O00-O95 in International Classification of Diseases-10; and “pregnancy-related deaths”, defined as any death occurring during the maternal risk period (pregnancy, delivery, 6 weeks postpartum, irrespective of cause.Results: The case definition had a major impact on levels and trends in maternal mortality. The obstetric mortality ratio averaged 185 per 100,000 live births over the period (60 deaths, whereas the pregnancy-related mortality ratio averaged 423 per 100,000 live births (137 deaths. Results from both calculations increased over the period, with a peak around 2006, followed by a decline coincident with the national roll-out of Prevention of Mother-to-Child Transmission of HIV and antiretroviral treatment programs. Mortality increase from direct causes was

  3. Investor's and procurement guide South Africa. Pt. 1. Heavy minerals, rare earth elements, antimony

    International Nuclear Information System (INIS)

    Graupner, Torsten; Schwarz-Schampera, Ulrich; Hammond, Napoleon Q.; Opperman, Rehan; Long'a Tongu, Elisa; Kenan, Abdul O.; Nondula, Unathi; Tsanwani, Matamba

    2014-01-01

    This is the first part of the ''Investor's and Procurement Guide South Africa'', a handbook for investing and doing business in South Africa's mineral industry. It is anticipated that this publication will aid potential investors into considering South Africa as an investment destination, not only for raw materials, but also for related industries. This manual supplements the many publications available on the economic geology and mineral wealth in South Africa and has been designed to guide prospective and current investors, suppliers and mine equipment exporters through the process of doing business in Africa's biggest and dynamic economy. As well as detailing the mineral raw materials heavy minerals, rare-earth metals and antimony, the handbook provides a general introduction to South Africa and its infrastructure, the economical, political and judicial frame of the South African mining industry and an overview of the economic geology. South Africa has a long and complex geological history which dates back in excess of 3.6 billion years. The country has a vast mineral wealth, undoubtedly due to the fact that a significant proportion of the Archaean and younger rocks have been preserved. The mining of the enormous Witwatersrand gold deposits, commencing in 1886, has led to the establishment of South Africa's well-developed infrastructure and to the sustained growth of an industrial and service sector in the country. With the world's largest resources of PGMs, gold, chromite, vanadium and manganese and significant resources of iron, coal and numerous other minerals and metals, the minerals industry will continue to play a pivotal role in the growth of South Africa's economy in the foreseeable future. South Africa is one of the top destinations in Africa for foreign direct investments. South African headquartered companies have been major investors into foreign direct investments on the African continent in the past decade. Investing in South African companies

  4. Preferences for ARV-based HIV prevention methods among men and women, adolescent girls and female sex workers in Gauteng Province, South Africa: a protocol for a discrete choice experiment.

    Science.gov (United States)

    Quaife, Matthew; Eakle, Robyn; Cabrera, Maria; Vickerman, Peter; Tsepe, Motlalepule; Cianci, Fiona; Delany-Moretlwe, Sinead; Terris-Prestholt, Fern

    2016-06-27

    For the past few decades, condoms have been the main method of HIV prevention. Recent advances in antiretroviral (ARV)-based prevention products have substantially changed the prevention landscape, yet little is known about how popular these products will be among potential users, or whether new methods might be used in conjunction with, or instead of, condoms. This study will use a discrete choice experiment (DCE) to (1) explore potential users' preferences regarding HIV prevention products, (2) quantify the importance of product attributes and (3) predict the uptake of products to inform estimates of their potential impact on the HIV epidemic in South Africa. We consider preferences for oral pre-exposure prophylaxis; a vaginal microbicide gel; a long-acting vaginal ring; a SILCS diaphragm used in concert with gel; and a long-acting ARV-based injectable. This study will gather data from 4 populations: 200 women, 200 men, 200 adolescent girls (aged 16-17 years) and 200 female sex workers. The DCE attributes and design will be developed through a literature review, supplemented by a thematic analysis of qualitative focus group discussions. Extensive piloting will be carried out in each population through semistructured interviews. The final survey will be conducted using computer tablets via a household sample (for women, men and adolescents) and respondent-driven sampling (for female sex workers), and DCE data analysed using a range of multinomial logit models. This study has been approved by the University of the Witwatersrand Human Research Ethics Committee and the Research Ethics Committee at the London School of Hygiene and Tropical Medicine. Findings will be presented to international conferences and peer-reviewed journals. Meetings will be held with opinion leaders in South Africa, while results will be disseminated to participants in Ekurhuleni through a public meeting or newsletter. Published by the BMJ Publishing Group Limited. For permission to use (where

  5. Alliance for Earth Sciences, Engineering and Development in Africa

    Science.gov (United States)

    Barron, E. J.; Adewumi, M.

    2004-12-01

    Penn State University, with a significant number of African University partners (University of Ibadan, University of Lagos, University of Cape Town, University of Witwatersrand, and Agustino Neto University) as well as HBCUs (Howard University and the Mississippi Consortium for International Development - a consortium of four HBCUs in Mississippi), has established the Alliance for Earth Sciences, Engineering and Development in Africa (AESEDA). AESEDA is designed to enable the integration of science, engineering, and social sciences in order to develop human resources, promote economic vitality and enable environmental stewardship in Africa. The Alliance has a coherent and significant multidisciplinary focus, namely African georesources. Education is a central focus, with research collaboration as one element of the vehicle for education. AESEDA is focused on building an environment of intellectual discourse and pooled intellectual capital and developing innovative and enabling educational programs and enhancing existing ones. AESEDA also has unique capabilities to create role models for under-represented groups to significantly enable the utilization of human potential. The efforts of the Alliance center around specific activities in support of its objectives: (1) Focused research collaboration among partner institutions, (2) Development of an international community of scholars, and (3) Joint development of courses and programs and instructional innovation. Penn State has a unique ability to contribute to the success of this program. The College of Earth and Mineral Sciences contains strong programs in the areas of focus. More than 25 faculty in the College have active research and educational efforts in Africa. Hence, the Alliance has natural and vigorous support within the College. The College is also providing strong institutional support for AESEDA, by establishing a Director and support staff and creating permanent funds for a unique set of new faculty hires

  6. Radon soil-gas concentration and exhalation from mine tailings dams in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Ongori, J.; Lindsay, R. [University of the Western Cape, Department of Physics, Private Bag X17, Bellville 7535 (South Africa); Newman, R. [Stellenbosch University, Department of Physics, Private Bag X1 Matieland 7602 (South Africa); Maleka, P. [iThemba LABS, Department of Nuclear Physics, P. O. Box 722, Somerset West 7129 (South Africa)

    2014-07-01

    In Africa as well as in the world, South Africa plays an important role in the mining industry which dates back almost 120 years. Mining activities in South Africa mainly take place in Gauteng Province. Every year million of tons of rocks are taken from underground, milled and processed to extract gold. The uranium bearing tailings are disposed in dumpsites. These tailings dumps contain considerable amounts of radium ({sup 226}Ra) and have therefore been identified as large sources of radon ({sup 222}Rn). Radon is a noble gas formed by the decay of radium which in turn is derived from the radioactive decay of uranium ({sup 238}U). Radon release from these tailings dumps pose health concerns for the surrounding communities. Radon soil gas concentrations and exhalations from a non-operational mine dump (Kloof) which belongs to Carletonville Gold Field, Witwatersrand, South Africa have been investigated. The continuous radon monitor, the Durridge RAD7 was used to measure {sup 222}Rn soil gas concentration in the tailings dump at five different spots. The radon soil gas concentration levels were measured at depths starting from 30 cm below ground/air interface up to 110 cm at intervals of 20 cm. The concentrations recorded ranged from 26±1 to 472±23 kBq.m{sup -3}. Furthermore, thirty four soil samples were taken from the spots where radon soil gas measurements were measured for laboratory-based measurement using the low background Hyper Pure Germanium (HPGe) gamma-ray detector available at the Environmental Radioactivity Laboratory (ERL), iThemba LABS, Western Cape Province. The soil samples were collected in the depth range 0-30 cm. After analysis the weighted average activity concentrations in the soils samples were 308±7 Bq.kg{sup -1}, 255±5 Bq.kg{sup -1} and 18±1 Bq.kg{sup -1} for {sup 238}U, {sup 40}K and {sup 232}Th, respectively. A number of factors such as the radium activity concentration and its distribution in soil grains, soil grain size, soil porosity

  7. Highlights from Johannesburg, Gauteng Province, South Africa

    Science.gov (United States)

    2002-01-01

    Although the extraction of mineral wealth has been the major influence in the history of Johannesburg and the surrounding Witwatersrand regions (with about 45% of all gold ever mined coming from there), the discovery of now-famous hominid fossils at the Sterkfontein Caves, and the convening of the world's largest-ever conference on environment and development, are setting a new stage for the future. The United Nations began the second Development and Environment Conference in Johannesburg on August 26, 2002. This meeting addresses the implementation of international goals to fight poverty and protect the global environment that were established at the first such conference held in Rio de Janeiro in 1992. The Johannesburg summit involves about forty thousand participants, and perhaps 100 world leaders. One of several official opening ceremonies for the conference was held at the Sterkfontein Caves to recognize the outstanding universal value of the paleo-anthropological fossils found there.These views from the Multi-angle Imaging SpectroRadiometer (MISR) highlight a number of the land use, vegetation, and geological features found within Gauteng Province (including the urban center of Johannesburg and the capital city Pretoria) and parts of the North West and Free State Provinces. The image on the right displays vegetation in red hues and is a false-color view utilizing data from MISR's near-infrared, red and blue bands. Both the natural-color view (left) and the false-color version were acquired by MISR's nadir camera on June 16, 2002. The urban areas appear as gray-colored pixels in the natural-color view, and exhibit colors corresponding with the relative abundance of vegetation found in the urban parts of this arid region.The mountains trending east-west near the center of the images extend from Pretoria in the east to Rustenberg in the west. These ranges, the Magaliesberg and Witwatersberg, separate the low-lying, hotter bushveld to the north from the cooler

  8. Primary care physician perceptions on the diagnosis and management of chronic obstructive pulmonary disease in diverse regions of the world

    Directory of Open Access Journals (Sweden)

    Aisanov Z

    2012-04-01

    Full Text Available Zaurbek Aisanov1,*, Chunxue Bai2,*, Otto Bauerle3,*, Federico D Colodenco4,*, Charles Feldman5,6,*, Shu Hashimoto7,*, Jose Jardim8,*, Christopher KW Lai9,*, Rafael Laniado-Laborin10,*, Gilbert Nadeau11,*, Abdullah Sayiner12,*, Jae Jeong Shim13,*, Ying Huang Tsai14,*, Richard D Walters11,*, Grant Waterer15,* 1Pulmonology Research Institute, Moscow, Russia; 2Department of Pulmonary Medicine, Fudan University, Shanghai, People's Republic of China; 3Centro Médico de las Américas, Mérida, Yucatán, Mexico; 4Hospital de Rehabilitación Respiratoria "María Ferrer," Buenos Aires, Argentina; 5Department of Internal Medicine, Charlotte Maxeke Johannesburg Hospital, Johannesburg, South Africa; 6Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 7Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan; 8Federal University of São Paulo, São Paulo, Brazil; 9Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, People's Republic of China; 10Faculty of Medicine, Universidad Autónoma de Baja California, Tijuana, Baja California, Mexico; 11Medical Affairs, GlaxoSmithKline, Brentford, UK; 12Department of Chest Diseases, Ege University Medical School, Izmir, Turkey; 13Department of Pulmonology, Guro Hospital, Korea University Medical Center, Seoul, South Korea; 14Department of Respiratory Care Medicine, Chang Gung Memorial Hospital, Chia-Yi, Taiwan; 15School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia*ICON group (International COPD Network, listed in alphabetical orderAbstract: Chronic obstructive pulmonary disease (COPD is a multicomponent disorder that leads to substantial disability, impaired quality of life, and increased mortality. Although the majority of COPD patients are first diagnosed and treated in primary care practices, there is comparatively little

  9. Initial report on drilling into seismogenic zones of M2.0 - M5.5 earthquakes from deep South African gold mines (DSeis)

    Science.gov (United States)

    Ogasawara, Hiroshi; Durrheim, Raymond; Yabe, Yasuo; Ito, Takatoshi; van Aswegen, Gerrie; Grobbelaar, Michelle; Funato, Akio; Ishida, Akimasa; Ogasawara, Hiroyuki; Mngadi, Siyanda; Manzi, Musa; Ziegler, Martin; Ward, Tony; Moyer, Pamela; Boettcher, Margaret; Ellsworth, Bill; Liebenberg, Bennie; Wechsler, Neta; Onstott, Tullis; Berset, Nicolas

    2017-04-01

    The International Continental Scientific Drilling Program (ICDP) approved our proposal (Ogasawara et al., EGU 2016) to drill into and around seismogenic zones where critically stressed faults initiated ruptures at depth. The drilling targets include four ruptures equivalent to M2.0, 2.8, 3.5, and 5.5 that dynamically and quasi-statically evolved in 2.9 Ga hard rock in the Witwatersrand basin, South Africa. Major advantages of our drilling locations are the large quantity and high-quality of existing data from dense seismic arrays both on surface and near-field underground in three deep South African gold mines. Additionally, the great depths (1.0 to 3.3 km from surface) to collar holes reduce drilling costs significantly and enable a larger number of holes to be drilled. Flexibility in drilling direction will also allow us to minimize damage in borehole or drilled cores. With the ICDP funds, we will conduct full-core drilling of 16 holes with drilling ranges from 50 to 750 m to recover both materials and fractures in and around the seismogenic zones, followed by core and borehole logging. Additional in-hole monitoring at close proximity will be supported by co-mingled funds and will follow the ICDP drilling. Expected magnitudes of maximum shear stress are several tens of MPa. We have established an overcoring procedure to measure 3D-stress state for adverse underground working conditions so as not to interfere with mining operations. This procedure was optimized based on the Compact Conic-ended Borehole Overcoring (CCBO) technique (ISRM suggested; Sugawara and Obara, 1999). Funato and Ito (2016 IJRMMS) developed a diametrical core deformation analysis (DCDA) method to measure differential stress using only drilled core by assuming diametrical change with roll angles caused by elastic in-axisymmetrical expansion during drilling. A gold mine has already drilled a hole to intersect the hypocenter of a 2016 M3.5 earthquake and carried out the CCBO stress measurement in

  10. Risk factors for suboptimal antiretroviral therapy adherence in HIV-infected adolescents in Gaborone, Botswana: a pilot cross-sectional study

    Directory of Open Access Journals (Sweden)

    Ndiaye M

    2013-09-01

    Full Text Available Maimouna Ndiaye,1,2 Peter Nyasulu,1 Hoang Nguyen,6,7 Elizabeth D Lowenthal,8,9 Robert Gross,10 Edward J Mills,3 Jean B Nachega4–6 1School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; 2Central Medical Stores, Ministry of Health, Gaborone, Botswana; 3Faculty of Health Sciences, University of Ottawa, Ottawa, Canada; 4Department of Medicine and Centre for Infectious Diseases, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa; 5Department of Epidemiology, Infectious Disease Epidemiology Research Program, Pittsburgh University Graduate School of Public Health, Pittsburgh, PA, USA; 6Departments of Epidemiology and International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; 7Tay Ho Clinics, Department of Medicine, Hanoi Health Services, Hanoi, Vietnam; 8Departments of Pediatrics and Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; 9Center for Pediatric Clinical Effectiveness, Children’s Hospital of Philadelphia, Philadelphia, PA, USA; 10Departments of Medicine and Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA Objective: Little is known about factors associated with suboptimal antiretroviral treatment (ART adherence among adolescents in Sub-Saharan Africa. Our objective was to determine the level of ART adherence and predictors of non-adherence among human immunodeficiency virus (HIV-infected adolescents at the Botswana-Baylor Children's Clinical Centre of Excellence in Gaborone, Botswana. Methods: In a cross-sectional study, 82 HIV-infected adolescents receiving ART and their caregivers were administered a structured questionnaire. The patient's clinical information was retrieved from medical records. Outcome measures included excellent pill count ART adherence (>95% and virologic suppression

  11. Felsic magmatism and uranium deposits

    International Nuclear Information System (INIS)

    Cuney, Michel

    2014-01-01

    The strongly incompatible behaviour of uranium in silicate magmas results in its concentration in the most felsic melts and a prevalence of granites and rhyolites as primary U sources for the formation of U deposits. Despite its incompatible behavior, U deposits resulting directly from magmatic processes are quite rare. In most deposits, U is mobilized by hydrothermal fluids or ground water well after the emplacement of the igneous rocks. Of the broad range of granite types, only a few have U contents and physico-chemical properties that permit the crystallization of accessory minerals from which uranium can be leached for the formation of U deposits. The first granites on Earth, which crystallized uraninite, dated at 3.1 Ga, are the potassic granites from the Kaapval craton (South Africa) which were also the source of the detrital uraninite for the Dominion Reef and Witwatersrand quartz pebble conglomerate deposits. Four types of granites or rhyolites can be sufficiently enriched in U to represent a significant source for the genesis of U deposits: per-alkaline, high-K met-aluminous calc-alkaline, L-type peraluminous and anatectic pegmatoids. L-type peraluminous plutonic rocks in which U is dominantly hosted in uraninite or in the glass of their volcanic equivalents represent the best U source. Per-alkaline granites or syenites are associated with the only magmatic U-deposits formed by extreme fractional crystallization. The refractory character of the U-bearing minerals does not permit their extraction under the present economic conditions and make them unfavorable U sources for other deposit types. By contrast, felsic per-alkaline volcanic rocks, in which U is dominantly hosted in the glassy matrix, represent an excellent source for many deposit types. High-K calc-alkaline plutonic rocks only represent a significant U source when the U-bearing accessory minerals (U-thorite, allanite, Nb oxides) become metamict. The volcanic rocks of the same geochemistry may be

  12. Felsic magmatism and uranium deposits

    International Nuclear Information System (INIS)

    Cuney, M.

    2014-01-01

    Uranium strongly incompatible behaviour in silicate magmas results in its concentration in the most felsic melts and a prevalence of granites and rhyolites as primary U sources for the formation of U deposits. Despite its incompatible behaviour, U deposits resulting directly from magmatic processes are quite rare. In most deposits, U is mobilized by hydrothermal fluids or ground water well after the emplacement of the igneous rocks. Of the broad range of granite types, only a few have have U contents and physico-chemical properties that permit the crystallization of accessory minerals from which uranium can be leached for the formation of U deposits. The first granites on Earth which crystallized uraninite appeared at 3.1 Ga, are the potassic granites from the Kaapval craton (South Africa) which were also the source of the detrital uraninite for the Dominion Reef and Witwatersrand quartz pebble conglomerate deposits. Four types of granites or rhyolites can be sufficiently enriched in U to represent a significant source for the genesis of U deposits: peralkaline, high-K metaluminous calc-alkaline, L-type peraluminous ones and anatectic pegmatoids. L-type peraluminous plutonic rocks in which U is dominantly hosted in uraninite or in the glass in their volcanic equivalents represent the best U source. Peralkaline granites or syenites represent the only magmatic U-deposits formed by extreme fractional crystallization. The refractory character of the U-bearing minerals does not permit their extraction at the present economic conditions and make them unfavourable U sources for other deposit types. By contrast, felsic peralkaline volcanic rocks, in which U is dominantly hosted in the glassy matrix, represent an excellent source for many deposit types. High-K calc-alkaline plutonic rocks only represent a significant U source when the U-bearing accessory minerals [U-thorite, allanite, Nb oxides] become metamict. The volcanic rocks of the same geochemistry may be also a

  13. Deep Microbial Ecosystems in the U.S. Great Basin: A Second Home for Desulforudis audaxviator?

    Science.gov (United States)

    Moser, D. P.

    2012-12-01

    crystalline rock fracture systems accessible via the world's deepest mines in South Africa. The D. audaxviator genome supports an inferred lifestyle dependent upon hydrogen and sulfate produced by natural radioactivity. Although relatives (e.g. at about 95% identity) are prominent in subseafloor habitats, with very few exceptions, South Africa's Witwatersrand Basin remains the generally-accepted geographic limit of D. audaxviator at the species level. Recently, however, 16S rRNA gene libraries from borehole water samples obtained by our group on the NNSS have produced a small number of sequences nearly identical to the African type sequence (~99% identity). One goal of this project was thus to confirm the presence and determine the relative abundance of candidatus Desulforudis audaxviator in a manmade radioactive subsurface habitat. Sequences assigned to the genus, Desulforudis appeared in the U12N.10 and ER-EC-11 pyrotag libraries. The highly radioactive U12N.10 tunnel sample had 9 unique operational taxonomic units ranging from ~93 to >99% similarity to D. audaxviator (1,189/21,291 ~5.6%). Of these, the most abundant OTU, with 1,082 sequences, was about 94% similar; whereas, only 7 individual sequences were nearly identical to D. audaxviator. The less radioactive ER-EC-11 had 9 unique OTUs ranging from ~93 to >99% similarity to D. audaxviator, of which 83 individual sequences were nearly identical to the African type.

  14. FOREWORD: International Conference on Planetary Boundary Layer and Climate Change

    Science.gov (United States)

    Djolov, G.; Esau, I.

    2010-05-01

    and convection in the climate system and the prominent demonstration of the climate sensitivity to the ocean heat uptake observed off Cape Town. The international conference responded to the urgent need of advancing our understanding of the complex climate system and development of adequate measures for saving the planet from environmental disaster. It also fits well with the Republic of South African government's major political decision to include the responses to global change/climate change at the very top of science and technology policy. The conference participants are grateful to the Norway Research Council and the National Research Foundation (NRF) RSA who supported the Conference through the project "Analysis and Possibility for Control of Atmospheric Boundary Layer Processes to Facilitate Adaptation to Environmental Changes" realized in the framework of the Programme for Research and Co-operation Phase II between the two countries. Kirstenbosh Biodiversity Institute and Botanical Gardens, Cape Town contribution of securing one of the most beautiful Conference venues in the world and technical support is also highly appreciated. G. Djolov and I. Esau Editors Conference_Photo Conference Organising Comittee Djolov, G.South AfricaUniversity of Pretoria Esau, I.NorwayNansen Environmental and Remote Sensing Center Hewitson, B.South AfricaUniversity of Cape Town McGregor, J.AustraliaCSIRO Marine and Atmospheric Research Midgley, G.South AfricaSouth African National Botanical Institute Mphepya, J.South AfricaSouth African Weather Service Piketh, S.South AfricaUniversity of the Witwatersrand Pielke, R.USAUniversity of Colorado, Boulder Pienaar, K.South AfricaUniversity of the North West Rautenbach, H.South AfricaUniversity of Pretoria Zilitinkevich, S.FinlandUniversity of Helsinki The conference was organized by: University of Pretoria Nansen Environmental and Remote Sensing Center With support and sponsorship from: Norwegian Research Council (grant N 197649