Geobotany, biogeochemistry and geochemistry in mineral exploration on the western fringes of the kalahari desert with specific reference to the detection of copper mineralization beneath transported overburden

The investigations outlined in this thesis were conducted in an attempt to establish the role of biogeography/geobotany, geochemistry and biogeo-chemistry in the detection of copper mineralization in bedrock concealed by transported material. To aid the interpretation of the results a detailed study of the physical background of the study area was necessary. Orientation studies were carried out overmineralized tilloid and mineralized lava, and comprised the mapping and/or recording of vegetation along transects, the establishment of plant species suitable for biogeochemistry and the copper content of various mesh fractions of the soil. Analytical techniques suitable for plant and soil sample analysis were also investigated. A regional biogeo-chemical/geochemical programme was carried out to locate extensions to known mineralization and also additional areas of mineralization. The biogeographical/geobotanical studies reveal the composition of anomalous and background vegetation units and indicate the influence of relief, drainage and lithology on plant species distribution. Over mineralized tilloid two plant species emerge as specific indicators of copper toxicity in the soil. The extent of the overburden limits the use of geobotany as a prospecting tool as vegetation is generally found to reflect overburden and soil types rather than concealed bedrock. Geochemistry, comprising analysis of the -270 mesh fraction of the soil by the acid leaching/atomic absorption spectrophotometry method, is found to give satisfactory results in areas of near surface bedrock. The value of biogeochemistry in areas of thick overburden is discussed, and of the tree and shrub species investigated Phaeoptilum spinosum is found to be the most suitable for further biogeochemical work. Dry ashing/acid digestion followed by atomic absorption spectrophotometry is a suitable method of analysis for plant samples. The limited success obtained in the regional biogeochemical/geochemical survey is probably due to the absence or low grade of mineralization in the tilloid and the lens-like occurrence of mineralization in the lava

Towards a conservation plan for the Cape Griffon Gyps coprotheres: identifying priorities for research and conservation

No Abstract. Vulture News Vol. 57 2007: pp. 56-5

Lentiviral manipulation of gene expression in human adult and embryonic stem cells

Human stem cells could revolutionize the field of medicine by providing a diverse range of cell types for tissue replacement therapies and drug discovery. To achieve this goal, genetic tools need to be optimized and developed for controlling and manipulating stem cells ex vivo. Here we describe a lentiviral delivery system capable of high infection rates in human mesenchymal and embryonic stem cells. The lentiviral backbone was modified to express mono- and bi-cistronic transgenes and was also used to deliver short hairpin ribonucleic acid for specific silencing of gene expression in human stem cells. We show that lentiviral transduction can be used to alter gene expression without altering the genes' ability to differentiate in vitro. These vectors will enable rapid analysis of gene function in stem cells and permit the generation of knock-in / knock-out models of human disease in the rapidly developing field of gene therapy

Gendering children's lives: TV fiction for South African kids

Gendering children's lives: TV fiction for South African kid

Liberatory violence or the gift: paths to decoloniality in Black Panther

Black Panther's (Coogler 2018) popularity amongst its black audiences in part stems from its foregrounding of the persistent social injustices engendered by colonialism and slavery (what Aníbal Quijano (2000: 533) terms' coloniality') and black people's struggles to overcome them. As a representational tactic in approaching this theme, the Hollywood blockbuster draws on the imaginings of Afrofuturism, which variously endorses radical or more conciliatory approaches to decoloniality. This southern theoretical approach and the critique of coloniality offered by Afrofuturism frame our exploration of how the film positions the hero, T'Challa and the villain, Erik Killmonger, as embodiments of contrasting approaches to emancipation from colonialism's entrenched legacy. Us-ing a structuralist approach that draws on the narrative models of Tsvetan Todorov, Vladimir Propp and Claude Levi-Strauss, we analyse the film's approach to decoloniality by examining the relationship be-tween T'Challa and Killmonger as the protagonist and antagonist re-spectively. The analysis reveals the limitations of the film's construction of the hero's and villain's understandings of the path to liberation. Ra-ther than offering a revolutionary remedy for the injustices of colonial-ism and its aftermath, the film embraces a liberal standpoint that re-mains palatable to the white establishment, both within Hollywood and the broader socio-political milieu

A continuous process for the biological treatment of heavy metal contaminated acid mine water

Alkaline precipitation of heavy metals from acidic water streams is a popular and long standing treatment process. While this process is efficient it requires the continuous addition of an alkaline material, such as lime. In the long term or when treating large volumes of effluent this process becomes expensive, with costs in the mining sector routinely exceeding millions of rands annually. The process described below utilises alkalinity generated by the alga Spirulina sp., in a continuous system to precipitate heavy metals. The design of the system separates the algal component from the metal containing stream to overcome metal toxicity. The primary treatment process consistently removed over 99% of the iron (98.9 mg/l) and between 80 and 95% of the zinc (7.16 mg/l) and lead (2.35 mg/l) over a 14-day period (20 l effluent treated). In addition the pH of the raw effluent was increased from 1.8 to over 7 in the post-treatment stream. Secondary treatment and polishing steps depend on the nature of the effluent treated. In the case of the high sulphate effluent the treated stream was passed into an anaerobic digester at a rate of 4 l/day. The combination of the primary and secondary treatments effected a removal of over 95% of all metals tested for as well as a 90% reduction in the sulphate load. The running cost of such a process would be low as the salinity and nutrient requirements for the algal culture could be provided by using tannery effluent or a combination of saline water and sewage. This would have the additional benefit of treating either a tannery or sewage effluent as part of an integrated process

A pilot course for training-in-context in statistics and research methods: Radiation oncology

Objectives. Inadequate training of investigators in statistics and research methods in Africa contributes to having limited local evidence and infrastructure to support multi-centre international trials. Methods of teaching junior oncology professionals tend not to emphasise research discovery, or the roles of emotional engagement and social networking in facilitating effective and efficient learning. We developed a strategy for teaching research methods and statistics in-context, centred on a shared international and practical research project. Design. An African research network (AFRES) was created and members conducted a pilot clinical registry study to acquire real-time data over a 4-month period in 2011. Following study closure, a proto-course consisting of 7 modules, each orientated to a practical topic in study development, implementation and reporting was administered over 18 weeks to all eight AFRES members. A survey of participants was conducted to evaluate the impact of this training strategy. Results. This strictly voluntary project had 5 of 8 AFRES members engaged in the process. Within one year, we generated and submitted two manuscripts and two news items for publication. Participants reported an increased understanding of the principles of evidence-based practice, research methods and interest in pursuing future research initiatives.Conclusion. A novel strategy to build international research infrastructure in Africa, grounded in a practical and relevant project, and which is collaborative and engaging, appears to be efficient and effective

Studies on the development of a vaccine against bovine ephemeral fever

Bovine ephemeral fever virus of low passage level (5th to 8th) in tissue culture has proved to be more antigenic for cattle than higher passage level (17th to 19th) or mouse-brain-adapted virus. However, the neutralizing antibody response appears to be short-lived and therefore probably provides inadequate protection. Similar results were obtained when ephemeral fever virus of both low and high passage level was adsorbed onto aluminium hydroxide and inoculated into cattle. Emulsions of ephemeral fever virus of both low and high passage level in Freund's incomplete mineral oil adjuvant induced high neutralizing antibody titres in vaccinated cattle. These antibodies were detectable for at least a year and the animals were found to be immune when infected with virulent bovine ephemeral fever virus.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Viruses isolated from Culicoides midges in South Africa during unsuccessful attempts to isolate bovine ephemeral fever virus

Five viruses, unrelated to bovine ephemeral fever virus (BEFV), were isolated from Culicoides biting-midges collected during the summer months of the years 1968-69 and 1969-70 near a cattle herd in which cases of BEF occurred and at an open horse stable at Onderstepoort. These viruses were investigated by means of serological, electron-microscopical and physicochemical tests. It was established that 2 isolates, Cul. 1/69 and Cul. 2/69, were related to each other and belonged to the Palyam subgroup of the genus Orbivirus, that isolate Cul. 3/69 belonged to the equine encephalosis subgroup of the genus Orbivirus, while Cul. 1/70 was related to Akabane virus, which belongs to the Simbu subgroup of the family Bunyaviridae. One isolate, Cul. 5/69, though prevalent in the cattle population, could not be identified at this point. A brief serological survey indicated that the cattle in the nearby herd possessed antibodies against all the isolates except Cul. 3/69. BEFV could not be isolated in mice or in cultured cells from the wild-caught Culicoides.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

Detection of antibodies to human herpesvirus 8 in Italian children: evidence for horizontal transmission

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma associated herpesvirus (KSHV), has been shown to be the causative agent for Kaposi's sarcoma (KS) and to be more prevalent in populations or risk groups at increased risk for KS. HHV-8 infection is rare in children from the US and the UK, but has been reported in African children. In this study we examine HHV-8 infection in children from Italy, a country with an elevated prevalence of HHV-8 in adults and high socio-economic conditions. © 2000 Cancer Research Campaig