South African Tuberculosis Vaccine Initiative

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    Non-specialist delivery of the WHO Caregiver Skills Training Programme for children with neurodevelopmental disorders: stakeholder perspectives about acceptability and feasibility in rural Ethiopia

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    Background: Autism and other neurodevelopmental disorders (NDD) are common in low- and middle-income countries (LMIC). However, services to address the needs of this group in LMIC are almost non-existent. The World Health Organization (WHO) developed the Caregiver Skills Training (CST) programme to be suitable for delivery in diverse global contexts. Ethiopia, the country of focus in this study, has a largely rural population and a lack of specialist service providers. Additional contextual challenges, including poverty, low literacy, limited access to healthcare and a lack of specialist child mental health services, may undermine the delivery of CST in this setting. This thesis, therefore, seeks to explore the acceptability and feasibility of non-specialist delivery of the WHO-CST from the perspective of providers and caregivers in rural Ethiopia. Methods: In Chapter one, a general literature review of neurodevelopmental disability and caregiver skills training is presented, with a focus on sub-Saharan Africa, to help contextualise the main qualitative study, outlined in chapter two. In-depth interviews were conducted with caregivers (n=19) who were all participants in two rural pilot studies of the WHO-CST programme. In addition, three focus group interviews were conducted with non-specialist facilitators (n=8), who facilitated the CST programme in two rural pilot tests. Data were analysed using the framework approach. Results: Findings were mapped onto the three framework themes created for this analysis: 1) Programme content: caregivers and facilitators uniformly indicated that the adapted programme addressed a need and was relevant for their context; caregivers emphasised how the programme helped them understand their child's problems and improve their skills to support their children; facilitators highlighted having acquired new knowledge and skills relating to NDD; 2) Programme facilitation: caregiver responses suggested that programme facilitation by non-specialists was acceptable; non-specialist facilitators emphasised the importance of support and supervision for the facilitators and simplification and modification of some concepts, such as the concept of play, and 3) CST training approach and delivery: participants indicated that the training modalities, including home visits and group training, were acceptable and feasible in the local context. Conclusions: This study suggested that, with some contextually appropriate modifications of programme content and delivery and continuing supervision of facilitators, the WHO-CST programme facilitated by non-specialists would be acceptable and feasible in rural Ethiopia. Results from this study may be useful to fine-tune the implementation of non-specialist delivery of the CST programme in Ethiopia, as well as other LMIC

    Methodological considerations related to the epidemiologic study of birth outcomes: maternal ART use and adverse birth outcomes

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    Background A major factor contributing to continued high under-five mortality in sub-Saharan Africa (SSA), is maternal HIV infection, which is associated with adverse birth outcomes such as preterm delivery (PTD), small-for-gestational age (SGA) and low birthweight (LBW) infants. Introduction of antiretroviral therapy (ART) during pregnancy has been a successful intervention for promotion of maternal and infant health, however it has also been linked to an increased risk of adverse birth outcomes. Consequently, the association between maternal ART use and these adverse outcomes is an important area of research in SSA which has the majority of pregnant women living with HIVand the highest rates of PTD, SGA and LBW infants. However, the current state of epidemiologic knowledge remains limited because most evidence on this association comes from observational studies, which have previously given inconsistent findings. Accordingly, the overarching aim of this PhD was to reliably quantify the relationship between maternal ART use and adverse birth outcomes, by addressing the role of methodological factors inherent in observational research in this association. Methods This research included pregnant women (aged ≥18 years) seeking antenatal care at a public sector midwife obstetric unit in Gugulethu (GMOU), Cape Town, enrolled into two separate dedicated research cohort studies. Enrolled women were followed-up during pregnancy and postpartum with their infants, with data obtained from study questionnaires, physical examinations and abstraction of clinical and obstetric records. In parallel, routine electronic data, linked across clinics and data sources were obtained for all pregnant women at the GMOU (pregnancy exposure registry (PER)) and across the Western Cape province (PHDC). Findings The incidence of gestational age (GA) based birth outcomes and the association between maternal ART use and these outcomes, was found to be substantially influenced by method of GA assessment used. While GA based on both last menstrual period (LMP) and measurement of symphysis fundal height (SFH) led to under and over estimation (relative to ultrasound), only LMP-based GA gave rise to a biased measure of association. Across data sources used in this research, an overall PTD incidence of 17% was observed which was lower than incidences observed in the pre-universal ART era. In the cohort studies, there was no significantly increased PTD risk in women living with HIV (compared to living without HIV), predominantly on the tenofovir + emtricitabine + efavirenz regimen. However, when assessed in the significantly larger population of pregnant women (PHDC), an increased PTD risk in women living with HIV was observed. There did not appear to be differences in PTD risk by ART status in the cohort studies or PER. However, across the province those initiating ART preconception were at increased PTD risk compared to those initiating during pregnancy. Blood pressure, particularly when assessed longitudinally played an important role in the association between maternal ART use and PTD, high normal and abnormal blood pressure trajectories associated with increased PTD risk. There did not appear to be any effect modification in the trajectory groups by HIV status for PTD. In the cohort study the overall incidence of SGA infants was 9%, with an increased SGA risk observed in women living with HIV compared to living without HIV. While no differences were observed in SGA risk by ART status, the highest risk was observed among women initiating in the second trimester. An overall LBW incidence of 13% was observed in the cohort study, with no differences observed in risk by HIV status or ART status. Blood pressure also played a role in the occurrence of LBW infants, with abnormal trajectories associated with increased LBW infant risk. Additionally, effect modification among women with abnormal trajectory groups, with women living without HIV at increased risk of LBW infants compared to women living HIV was observed. Finally, investigating this association using both cohort studies and population based electronic health care data proved to be valuable. The three data sources gave similar effect estimates, with varying levels of precision, and each with distinct but complementary benefits. The cohort studies and PER included smaller select groups of women and provided detailed investigation of risk factors that could impact the overall association. In contrast the provincial dataset, had limited risk factor data, but provided overall associations with the ability to detect subtle differences. Conclusion Reassuringly, the magnitude of difference in PTD risk by HIV status under policies of universal maternal ART use, appears to be smaller than in the past. Of concern, however, was the finding of increased SGA risk. Taken together, these findings highlight the need to improve mechanistic understanding of ART-mediated adverse birth outcomes, in order to ensure optimal maternal and infant outcomes. The methodological findings underscore the importance of considering the potential for bias related to selection and measurement when designing and/or evaluating findings from studies investigating this association and by extension other medications in pregnancy

    Glass Tower

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    “Glass Tower” is a story about a growing friendship between Leilah and Frankie, two teenage newcomers to a middleclass government school in Durban, South Africa. It's set in the late 1990's, a period of flux following the country's first democratic election, and it's within this context of social change and discomfort that these two very different outsiders come to grips with their changing bodies and place in the world. Bound together by loneliness, and a joint curiosity in their burgeoning sexuality, Leilah and Frankie come to share their deepest secrets with one another. It's an unveiling that stretches the limits of their friendship and pushes Leilah to discover parts of herself that without Frankie she would have left in the dark. Issues of race and sexual abuse are raised, but it is the affection between these two characters, and the discoveries they make as they learn and teach one another, that drives the story forward

    Molecular Characterisation of Diffuse Large B-cell Lymphoma in South Africa

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    Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous and aggressive disease and is the most common subtype of non-Hodgkin lymphoma (NHL) in adults. Additionally, this subtype of lymphoma is also the most common in people infected with the Human Immunodeficiency virus (HIV), and the incidence has remained high despite the advent of Antiretroviral therapy (ART). About 30-40% of DLBCL patients' relapse, or are refractory to standard first-line therapy, and this is attributed to the high genetic and clinicopathological heterogeneity of the disease. Reports indicate that, among HIV-positive DLBCL patients, the response rate is even poorer. In low resourced settings, this is further aggravated by multiple factors including access to health facilities and gaps in communication. Recent genetic studies of DLBCL tumours allowed for the further subclassification of the ABC- and GCB- subtypes into at least 5 new groups, each with distinct genetic, molecular and clinicopathologic features, revealing potentially novel drivers of the disease. There is therefore a need to further understand the molecular pathology of these distinct subtypes, including within the context of HIV. The latter formed the basis of this study and used multiple approaches and methodologies, including immunophenotyping and mutational analysis of samples from local patient cohorts, as well as gene set enrichment analyses of publicly available DLBCL datasets. An analysis and comparison of immune cell populations in peripheral blood mononuclear cells, of HIV negative and HIV positive DLBCL patients was performed using flow cytometry (Chapter 3). The participants were newly diagnosed, chemotherapy naïve DLBCL patients. Some of the key observations were as follows: HIV-positive patients were diagnosed with DLBCL at significantly younger ages (75% under the age of 50 years), compared to the HIV negative DLBCL group. Furthermore, more extranodal disease and EBV infection were observed in the HIV-infected group, and both these factors are known to be indicative of more aggressive, advanced-stage disease. In general, cytopenias were observed in the DLBCL patient cohort, regardless of HIV status. Since most of the HIV infected patients were not adequately receiving antiretroviral therapy at the time of DLBCL diagnosis, the CD4+ helper T-cell population within this group was significantly reduced, in comparison to the HIVuninfected group. Interestingly, there was a significant difference in monocyte count between the two groups, with lower counts observed among the HIV-infected DLBCL patients. Additionally, increased activation of cytotoxic T-cells (CD8+CD38+), as well as lower mature cytolytic CD56dimCD16+ Natural Killer (NK) cells were observed in the HIV-positive DLBCL group. The prevalence of Myeloid differentiation primary response factor 88 (MYD88) L265P and Cluster of Differentiation 79B (CD79B) Y196 activating mutations were analysed in a cohort of archived ABC-DLBCL tumours (consisting of both HIV positives and negatives) (Chapter 4). Genomic DNA was isolated, the relevant genomic regions amplified by PCR, subjected to Sanger sequencing and then analysed and confirmed. The co-occurrence of both these mutations is characteristic of a newly described subset of DLBCL shown to have an inferior outcome. The prevalence of these mutations within an African population has as yet not been reported. The MYD88L265P mutation was detected in 26% of the amplified ABC-DLBCL tumours, while mutations at CD79BY196 were observed in 12% of the tumours. Co-occurrence of both these MYD88 and CD79B mutations were present in only 3 tumours, all of which were HIVnegative. Analysis of patient survival in relation to the mutations highlighted a trend showing that patients harbouring both mutations had worse overall survival. Interestingly, this pathogenic effect was more prominent for CD79B mutations, and this was comparable to the survival probability observed for HIV-positive patients. For the MYD88L265P mutation, an HIV positive status further decreased the survival probability. The final study presented in this thesis focused on investigating the expression and regulation of the Suppressor of cytokine signalling 1 (SOCS1) gene. SOCS1 has been recently reported to be a frequently altered gene in DLBCL, but molecular pathological studies on the role of SOCS1 in DLBCL are scarce. Using cell line models, basal SOCS1 gene and protein expression levels were assessed. In two DLBCL cell lines (SUDHL-4/GCB-DLBCL subtype and HBL-1/ABC-DLBCL subtype), SOCS1 expression was reduced at both the mRNA and protein levels when compared to control lymphoblastoid cell lines (LCLs), while in a third ABC-DLBCL cell line (U2932), results were varied. In silico analysis using the Cancer Genome Atlas (TCGA) database confirmed that SOCS1 is in the top 20 frequently mutated genes in DLBCL. Furthermore, these frequent mutations, which lead to reduced or low SOCS1 expression, are associated with DLBCL disease in its early stages (stages I and II) and with better survival estimates. In contrast, high expression of SOCS1 was associated with poor overall survival. This was further corroborated by gene set and pathway enrichment analyses, which highlighted factors involved in the enhancement of cancer-promoting processes such as proliferation, migration, invasion, and metastasis. Additionally, a previously reported association between the expression of methylation-related genes and SOCS1 expression was confirmed. Overall, these studies have uncovered novel insights into the pathology of DLBCL, including features unique to HIV-associated DLBCL. The implementation of a differential approach to the management of the disease, based on specific genetic and molecular features, should be explored. These findings support the importance of more studies, incorporating comprehensive genomic and molecular technologies, to continue to unravel the complex disease that is DLBCL

    Protecting our wildlife for life: a discussion on how we have failed to protect our rhino populations in the past and what our future options really are

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    The poaching of the rhino of southern Africa is not a new debate. In fact, it has been a key area of environmental concern for a number of years. Today, it falls under the rubric of ecological criminology which shall be addressed in this dissertation. I intend to deal with the impact poaching and the illegal trade has had on this endangered species and, in addition, to give an overview of the current measures of the criminal justice system in force to combat it. I shall discuss the international perspective and propose some solutions to prevent the further elimination of the species. Approximately 350 million wild animals and plants are traded each year world-wide, estimated to be worth US $20 billion per year. It is argued that up to a quarter of this trade may be illegal .and, thus after drugs and weapons it is the third most significant trade internationally. This illegal activity continues despite the operation of an international convention aimed to prevent it, the Convention on International Trade in · Endangered Species of Wild Fauna and Flora, (CITES). I shall address many of the attributes of CITES, but also consider its numerous flaws which have failed to protect · the rhino adequately

    Mammalian and avian diversity in a coastal nature reserve and an adjacent eco-estate

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    The burgeoning human population is placing increasing pressure on natural resources, including undeveloped land, for a variety of human activities including residential housing. Despite making up only a small percentage (5.4 %) of transformed land, urban areas have had a disproportionate impact on biodiversity with many cities having been founded in biodiversity hotspots at the confluence of marine, freshwater and terrestrial ecosystems. A growing trend worldwide and particularly in countries with a large wealth gap is the development of low density private residential estates. Although primarily conceived to improve home security, private estates are nevertheless regarded as a form of geographical escapism, and they are increasingly being marketed as eco- and lifestyle estates. While no formal definition of an eco-estate exists nor what ecological criteria must be satisfied to qualify for the status of an “ecological estate,” increasingly such estates make bold claims concerning their contributions to the conservation of native flora and fauna. Currently, little is known about the impacts of eco-estates on the ecology and wildlife of an area, particularly when compared to natural land. To date, most research on estates has focused on comparing their impact with transformed, agricultural or even urban land uses. In this study I compare select elements of the fauna within a golfing eco-estate (Atlantic Beach Estate), located 25 km north of Cape Town to the neighbouring Blaauwberg Nature Reserve, from which the estate was originally cleaved. I used live trapping, camera trapping and point counts for small mammals, medium/large mammals and birds respectively to compare the fauna in both the estate and reserve. For birds I was able to include a before and after comparison with a similar study in the early phases of the estate's development. All fieldwork was conducted between September and November 2019. Small mammal diversity was similar within the estate and the reserve, but the former included an exotic invasive (the house rat (Rattus rattus)) while the latter supported the vulnerable white-tailed rat (Mystromys albicaudatus). Medium sized mammal species composition varied significantly between the estate and reserve with the latter having more native species and the estate having three domestic species in addition to an introduced, extralimital wild species, the springbok (Antidorcas marsupialis). Bird communities were similar, with marked overlap in species between the two land uses. The addition of permanent water and private gardens with both native and non-native flora has increased both the niche breadth and food availability within the estate which was reflected in a higher avian diversity than in the neighbouring, more homogenous, reserve. In addition to supporting almost all the species found in the reserve, the estate was able to support multiple fynbos-endemic species not found in the nature reserve, as well as species closely associated with water. The presence of the eco-estate does not appear to have negatively impacted the bird community as the additional resources provided by the estate allow both urban exploiters and urban tolerators/avoiders to persist. In summary the estate has adversely impacted medium sized mammals more than both small mammals and birds with the latter taxon arguably benefiting from the increased habitat heterogeneity. Improving medium sized mammal richness would require increasing the permeability of the estate boundary but this will compromise both the safety of residents from external human threats and mammals within the reserve from domestic animals originating from the estate. Restricting domestic animals to private property, eliminating exotic species, improving connectivity between patches of natural habitat and naturalizing the edges of the golf course are all attainable goals that may improve small mammal and bird communities within the estate. However medium and large mammals are seldom compatible with human habitation and are thus likely to be the faunal component most adversely impacted by eco-estates with their limited size and impermeable edges. Ultimately while eco-estates may offer habitat for some species, they are not uniformly suitable for all species, and particular attention must be given to characteristics of prevailing species which might preclude them from an estate before estate construction. Given the increasing popularity of eco-estates and increased pressure on wildlife these are important findings which can help improve conditions for wildlife on current eco-estates and help facilitate site selection for any future eco-estate construction

    Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019

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    Penguins are among the most important avian predators in the Southern Ocean, consuming large amounts of prey. Macaroni Penguins Eudyptes chrysolophus and Eastern Rockhopper Penguins E. filholi are listed as Vulnerable due to large-scale population declines across their distributions. The aim of my thesis is to update trends in the breeding populations of Macaroni and Eastern Rockhopper Penguins at Marion Island from 1994–2019. The breeding population of Macaroni Penguins has decreased more or less consistently at an average rate of 1.9% per year since 1994, whereas Eastern Rockhopper Penguins showed a rapid initial decline of 13% per year from 1994–2001, then stabilised to fluctuate between 55 000 and 80 000 pairs. I assess the long-term trends in pre-breeding condition (arrival dates and mass on arrival for breeding) and breeding performance (breeding success and fledgling mass) of both Macaroni and Eastern Rockhopper Penguins. I also compare within and between these variables to explain trends in the breeding population of both penguins for the last two decades. There was inter-annual variation in pre-breeding variables (arrival dates and mass on arrival) and breeding variables (breeding success and fledging mass) in both penguins which could indicate variability in prey availability and climatic conditions across the breeding seasons from 1994–2019. Over the study period, Macaroni Penguins arrived to breed 3–5 weeks earlier than Eastern Rockhopper Penguins on Marion Island. There was no consistent trend in mass on arrival among male or female Macaroni Penguins but Eastern Rockhopper Penguin mass on arrival decreased from 1994 to 2007 and then had an increasing trend post 2007 for both sexes. Breeding success of Macaroni Penguins fluctuated annually with no obvious trend, whereas the breeding success of Eastern Rockhopper Penguins increased at all three study locations. This increase in body condition and breeding success could explain the stabilising population of Eastern Rockhopper Penguins at Marion Island. Breeding variables (breeding success, fledgling mass) of both penguins were related to pre-breeding variables (arrival dates and mass at arrival). The breeding performance of both penguins is not only affected by localised prey availability and climatic conditions during breeding, but the effect might potentially be at a broader scale, before the onset of breeding. I used diet samples collected from these two species during breeding to determine interannual variation in prey composition to assess whether long-term changes in diet might explain trends in their breeding populations. The population size of the two penguins at Marion Island is more evenly matched compared to any other location where the two Eudyptes penguins breed sympatrically. They are expected to exhibit a level of segregation in their biology to allow their co-existence, from selection of breeding grounds, foraging strategies, diet and response to changing oceanographic conditions. I also tested for differences in preferred prey species. Both penguins mainly fed on euphausiids Thysanoessa vicina and Euphausia vallentini. Myctophid fishes (mainly Krefftichthys anderssoni and Protomyctophum tenisoni) were more important in the diet of Macaroni than Eastern Rockhopper Penguins. There was no long-term change in their diets that could explain their decreasing population trends at Marion Island. However, the more diverse diet of Macaroni Penguins could potentially allow them to compensate for years of low euphausiid availability compared to Eastern Rockhopper Penguins. The considerable overlap in diet between the two penguins suggests potential competition of resources between the two penguins, during breeding. Variation in breeding performance of both Macaroni and Eastern Rockhopper Penguins was related to breeding diet composition. Macaroni Penguins had higher breeding success when they fed more on myctophids, whereas Eastern Rockhopper Penguins fledged lighter chicks when they preyed on myctophids. Macaroni Penguins are more efficient at foraging on myctophids compared to Eastern Rockhopper Penguins and hence, foraging on myctophids could have opposing effects on duration of foraging, provision rate and parental care between the two penguin species. Variation in the diet composition when breeding was related to the latitudinal position of the oceanic fronts. Macaroni and Eastern Rockhopper Penguins fed on more fish Protomyctophum tenisoni when the Sub-Antarctic Front (SAF) and Antarctic Polar Front (APF) were further away from Marion Island and fed on more crustaceans Thysanoessa vicina when the fronts were closer to the island. The variable latitudinal position of the fronts is known to influence species composition and oceanographic conditions around the Island. Variation in breeding performance was not readily explained by large-scale oceanographic conditions or local scale oceanographic conditions except for sea surface height (SSH). Macaroni Penguins tended to fledge heavier chicks in years of low SSH, associated with more upwelling and mesoscale eddies, whereas Eastern Rockhopper Penguins tended to fledge heavier chicks in years of higher SSH associated with less upwelling and fewer mesoscale eddies. This indicates the difference in habitat preference and response to oceanographic conditions between the two penguin species: Macaroni Penguins forage in cooler waters compared to Eastern Rockhopper Penguins. In summary, this study reports trends in the population size, breeding performance and diet of two sympatric penguin species and how they respond to their environment. Both penguins' populations have been decreasing since 1994 but for the Eastern Rockhopper Penguin most of the decline happened before 2001 and their population has since stabilised. The two-closely related penguins manage to segregate some aspects of their ecology to facilitate co-existence on the same island while foraging in broadly the same area and feeding on the same prey. Macaroni Penguins arrive on the Island 3–5 weeks earlier than Eastern Rockhopper Penguins, which reduces competition for resources during breeding. Macaroni Penguins have a more diverse diet and feed on more fish compared to Eastern Rockhopper Penguins. The breeding performance of Macaroni Penguins responded positively to fish in their diet while Eastern Rockhopper Penguin chick condition was negatively affected by fish in their diet. The breeding biology and diet of the two penguins responded to changes in oceanographic settings around Marion Island, showing the possible effect of climate change on these two species

    Surface tension: permeability, the body, and installation

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    Surface Tension – Permeability, the Body, and Installation, is comprised of a multimedia installation and an accompanying minor thesis. The concurrent points of departure for both are the body and the medium of installation itself, exploring their sympathies with the lens of permeability. The installation presents sculptures and video montage works that make use of medical, religious, and pathological renderings of the body, drawing attention to its varied portrayal as reliant on parallel visual technologies. The navigable and immersive nature of installation is used to suggest a reading of the body as permeable, constructed, and fluid. In the document, these portrayals are discussed via an arthistorical case-study approach, each suggested as varying depictions of bodily permeability. In particular, the Cartesian body as the product of Judeo-Christian morality, the Descartes mind-body split, Enlightenment secularization, and Western medical representation that renders the body as a discrete organism ending at the skin is tracked. The project attempts to unsettle this paradigm by focusing on the dialectic of porosity, which aims to situate the body in dialogue with systems beyond itself via consumption, excretion, and infection. The second aspect of the research is an extrapolation of this porous dialectic to modes of representation and their consequent ways of seeing. The Cartesian bodily paradigm is suggested as parallel to the rise of ocularcentrism. Whilst acknowledging the strengths of various mediums, attention is called to the capacity of static, 2D media to emphasize ocularcentric disembodiment. In contrast, installation is explored as a medium that demonstrates a porous capacity via the viewer's occupation of an immersive environment designed to activate multiple senses, thus aligning message and medium

    The petrogenesis and geochemistry of the Namaqualand olivine melilitite pipe cluster, western South Africa

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    The Namaqualand olivine melilitite pipe cluster is a 40 km by 10 km north/south oriented area with at least 10 closely spaced alkaline ultramafic subvolcanic pipes and diatremes containing olivine melilitite and nephelinite, spanning an age range of 35-56 Ma. A related carbonatite complex containing olivine melilitite is also found within this cluster, with an emplacement age of ≈ 55 Ma. The Namaqualand cluster represents the southernmost component of the Late Cretaceous to Paleogene-age Namaqualand-Bushmanland-Warmbad (NBW) lineament, representing a 400 km long NNE-SSW trending feature made of hundreds of diatremes containing ultramafic lamprophyre and kimberlite in addition to the rock types named above. The NBW lineament appears to be an ageprogressive feature, with ages increasing toward the northeast at a rate and direction roughly consistent with Late Cretaceous to Cenozoic African plate motion. This suggests that it could have formed from a single source, such as a mantle plume, with the earlier products being the Warmbad kimberlites, followed by the later diatremes of the Bushmanland cluster and the youngest being the Namaqualand olivine melilitites. This study focuses on the petrography and geochemistry of fresh igneous rocks sampled from 10 pipes in the Namaqualand cluster. The samples have unusual compositions for diatreme-hosted alkaline igneous rocks in that they are relatively differentiated, with whole rock Mg numbers of between 71 and 45. This suggests that many of these samples represent magmas that evolved though more than 50% fractional crystallization of mineral assemblages dominated by olivine but also containing significant melilite, nepheline, phlogopite, titanomagnetite and perovskite. However, least-squares fractionation modelling appears to only provide an approximate guide to the fractionating mineral assemblages. The concentrations of most incompatible trace elements in the Namaqualand melilitites are relatively uniform, suggesting a common source and petrogenesis. Low Pb concentrations in the Namaqualand melilitites, along with their SiO2- and Al2O3-poor major element compositions make it unlikely that they experienced significant (e.g., more than 5-10%) assimilation of local continental crust. The Namaqualand melilitites are characterized by extraordinarily high and variable Nb/Rb and U/Th ratios, and correlations with other elements indicate that these ratios have been affected by variable fractional crystallization of phlogopite and perovskite, respectively. However, this cannot explain the unusually high U concentrations and low Th/U ratios of the most primitive Namaqualand melilitites, which appear to be a source feature. Oxygen isotope ratios of olivine separates indicate that olivines from a large majority of the melilitite pipes have compositions indistinguishable from those from typical upper mantle peridotite (4.9-5.2‰). However, three melilitite pipes emplaced within the mid-Cretaceous Koegel Fontein igneous complex contain M. D. Kirchner University of Cape Town (2022) MSc Thesis olivines with exceptionally low δ18O values (i.e., down to +4.2 ‰). The crustal country rock surrounding the Koegel Fontein complex, as well as igneous rocks strongly contaminated by this crust, have exceptionally low δ18O values (down to -4 and -5.3‰, respectively). The unusually low -δ 18O values of these olivines could be explained by the assimilation of up to 10% of Koegel Fontein country rock crust having the lowest δ18O values measured. Larger amounts of crustal assimilation are not plausible as they would result in detectable increases in SiO2 and Pb/Ce ratios. It is unclear whether the crustal assimilation detected in the melilitites emplaced within the Koegelfontein complex is typical of most Namaqualand melilitites. The Namaqualand melilitites have radiogenic isotope compositions that overlap with those of melilitites and kimberlites from the Bushmanland and Warmbad clusters, as well as with southern African Group I kimberlites. However, the Namaqualand pipes are unique in that some samples have radiogenic isotope values approaching those of HIMU oceanic island basalts (e.g., from St. Helena, Mangaia, Tubuai), whereas the Bushmanland and Warmbad clusters display isotopic compositions that only extend to weaker HIMU signatures. The geochemical and age-distance patterns displayed by the NBW igneous rocks are most consistent with the action of a mantle plume passing beneath the western margin of southern Africa in the Late Cretaceous to Paleogene, resulting in the generation of the NBW lineament. This is consistent with the fact that the samples with the strongest HIMU signatures in the NBW lineament are those that have been emplaced on the thinnest lithosphere, nearest the continental margin. The HIMU signature dominant in the Namaqualand melilitites is presumably related to the plume source, which could contain ancient recycled oceanic crust. The formation of the African megalineament could theoretically be related to the same plume that caused the NBW lineament by triggering a zone of magmatism along a deep-seated zone of weakness in the lithospheric mantle between Southern Africa into the east African rift zone, however, more evidence would be needed to fully support this possibility

    The integration of education and training in further education and training : towards a pedagogy of mode-switching

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    The integration of different types and areas of knowledge and skills is being explored for the first time in the official discourse on educational reconstruction in South Africa. The reasons for this are bound up with the country's general global conditions of capital accumulation and its political and social history. The conceptually and practically integrated curricula envisaged pose some challenges that will have to be addressed. On the one hand, the culture of democracy presently being introduced in the educational arena leads to notions of learner autonomy, self-realisation, recognition of diversity, and socio-economic redress and equity. On the other hand, the present conditions of capital accumulation accentuate the market discourse of efficiency, competitiveness and tangible outcomes


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