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An investigation of how the Namibian Environmental Education Course has shaped and informed the practice of non-formal environmental educators in Namibia

  • Authors: Namutenya, Martina
  • Date: 2010
  • Subjects: Environmental education -- Namibia , Environmental education -- Study and teaching -- Namibia , Non-formal education -- Namibia , Sustainable development -- Namibia , Environmental literacy -- Namibia , Environmental literacy -- Study and teaching -- Namibia , Conservation of natural resources -- Study and teaching -- Namibia
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:2000 , http://hdl.handle.net/10962/d1015225
  • Description: Before Namibia's independence in 1990 educational programmes and curricula gave little attention to environmental education which was detrimental to the development of environmental literacy in Namibia. The post independence education reform process paid special attention to the inclusion of environmental education in all spheres of learning. Furthermore, Namibia became a signatory to various environmental conventions thereby raising awareness about the environment and the potential challenges to a sustainable future. The initiatives of various environmental education projects since independence have responded to the growing concern of environmental education programmes, resulting in the establishment of the Namibian Environmental Education Course (NEEC). To date few studies have been conducted examining the relevance of EE programmes in relation to the professional practice of EE providers in the non-formal sector. This study focuses on the work done by two environmental education providers and four assistant environmental education tutors in Rundu, in North-Eastern Namibia. The study adopted a qualitative approach to investigate how the NEEC has shaped and informed the practice of EE providers in the non-formal sector and also how the NEEC has responded to the Education for Sustainable Development (ESD) programme. The study employed three data collection instruments: interviews, field observations and document analysis. The findings indicated that despite the input of the NEEC programme which provided an understanding and knowledge of environmental problems to the EE providers, there are issues that continue to hamper the effective practice of these providers. The study revealed that the NEEC programme, while within the structure of ESD, does not give explicit guidelines for identifying Namibia's environmental challenges and clear strategies of how to respond to these challenges. The findings of the study have provided valuable insights into aspects of an EE programme that need to be addressed to support EE providers in responding to key environmental challenges in their regions and contribute to the decade of Education for Sustainable Development.
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  • Date Issued: 2010

An evaluation of the brand campus concept implemented at Mercedes-Benz South Africa: a case study

  • Authors: Samkange, Tichaona
  • Date: 2009
  • Subjects: Mercedes-Benz of South Africa DaimlerChrysler -- South Africa Consumer satisfaction Case studies -- South Africa Product management Case studies -- South Africa Brand name products -- Management Case studies Brand name products -- Valuation Case studies Marketing Case studies -- South Africa Brand choices Case studies -- South Africa Customer preferences Case studies -- South Africa
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:741 , http://hdl.handle.net/10962/d1003861
  • Description: Primarily, this research study was concerned with the evaluation of the brand campus concept implemented at then DaimlerChrysler South Africa in 2002, as a case study. Pretoria-based Mercedes-Benz South Africa (Pty) Ltd. (MBSA) is a subsidiary of global vehicle manufacturer Germany’s Daimler-Benz AG (DBAG). They are responsible for assembling, distributing and retailing, certain Mercedes-Benz and Mitsubishi vehicle brands, and spare parts. The landmark 1998 DaimlerChrysler global ‘merger of equals’ was preceded by the 1995 joint venture between Mercedes-Benz and Mitsubishi Motor Corporation. Consequently, three brands (Mercedes-Benz, Chrysler and Mitsubishi) were retailed and marketed under DaimlerChrysler South Africa (Pty) Ltd. (DCSA), positioned next to each other in the same showroom. This report identifies key challenges stemming from this approach, namely: brand strength dilution, more than 80 multi-franchised dealers and multi-branded showrooms, service capacity problems, old working environment and infrastructure, and perceived intra-brand competition. The research evidence suggests that these problems prompted then DCSA to launch the 2000 Dealer Network Strategy (DNS). In the grand scheme of things, the DNS intervention entailed partitioning the dealer network into five brand centres in five metro regions, and eighteen market centres in the rural areas. The brand campus concept was borne out of DNS and proved to be a masterstroke since, the primary focus was on streamlining the retail facilities for DCSA vehicle sales, service and spare parts for both the passenger and commercial vehicles. This study highlights key pillars of the brand campus concept, namely: profitability, brand focus, customer orientation and diversity. The challenge was to address seven major drivers of the brand campus concept, namely: after-sales vehicle support, vehicle service capacity, lead-times, spare parts availability, sales information propagation, behavior of sales personnel and the overall vehicle dealership appearance. Semi-structured interviews constituted part of the evaluation based on the perspectives of five customers, three dealer principals and two MBSA marketing executives. The research evidence, which also came from MBSA documentation and direct observation, shows that this innovative concept has been remarkably successful.
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  • Date Issued: 2009

The design and synthesis of novel HIV-1 protease inhibitors

  • Authors: Tukulula, Matshawandile
  • Date: 2009
  • Subjects: Protease Inhibitors HIV infections -- Treatment AIDS (Disease) -- Treatment HIV (Viruses) Indolizine -- Derivatives Heterocyclic compounds -- Derivatives Nuclear magnetic resonance Quinoline
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4305 , http://hdl.handle.net/10962/d1004963
  • Description: This study has focused on the synthesis of truncated analogues of the hydroxyethylene dipeptide isosteres, such as Ritonavir®, currently in clinical use as HIV-1 protease inhibitors. The reactions of pyridine-2- and quinoline-2-carbaldehydes with methyl acrylate, in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) or 3- hydroxyquinuclidine (3-HQ) as nucleophilic catalysts, have afforded a series of Baylis- Hillman adducts, acetylation and cyclisation of which have provided access to a series of indolizine-2-carboxylate esters. The carboxylic acids, obtained by base-catalyzed hydrolysis of these esters, have been coupled with various protected (and unprotected) amino compounds using the peptide coupling agent, 1,1’-carbonyldiimidazole (CDI), to afford a series of indolizine-2-carboxamides as indolizine-based truncated Ritonavir® analogues in quantitative yield. Aza-Michael reactions of pyridine-3-carbaldehydederived Baylis-Hillman adducts with various amino compounds have provided access to a range of pyridine-based products as mixtures of diastereomeric aza-Michael products. The assignment of the relative stereochemistry of the aza-Michael products has been established using 1-D and 2-NOESY experiments and computer modelling techniques. Computer modelling studies have also been conducted on selected aza-Michael products using ACCELRYS Cerius2 software, followed by interactive docking into the HIV-1 protease receptor site, using AUTODOCK 4.0. The docking studies have revealed hydrogen-bonding interactions between the enzyme and the synthetic ligands. Saturation Transfer Difference (STD) NMR experiments have also indicated binding of some of the aza-Michael products to the HIV-1 protease subtype C enzyme, thus indicating their binding and possible inhibitory potential.
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  • Date Issued: 2009

An exploratory investigation of the factors that influence the retention of knowledge workers at the National Energy Regulator of South Africa

  • Authors: Nompula, Thami Ignatius
  • Date: 2007
  • Subjects: National Energy Regulator (South Africa) Knowledge workers
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:771 , http://hdl.handle.net/10962/d1003892
  • Description: The research, investigating how a selected group of former BETD graduates understand and implement the theory of reflective practice, is a qualitative case study carried out in the Kavango region of Namibia. The study was shaped by one of the major policy emphases in Namibia’s post independence teacher education reform process - that of developing reflective teachers who actively participate in curriculum planning and take educational decisions based on their own judgment. A basic assumption underlying the study is that effective educational practice is dependent on practitioners thinking about what they are doing and acting on their reflections to improve practice. The study found that a fundamental problem preventing these teachers from implementing reflective practice in accordance with the Namibian educational reform process, is that the participating teachers neither understand the exact meaning of reflective practice nor do they have a common or shared view of the concept, in spite of their common qualifications. A key contributing factor to their problems withimplementing reflective practice is the lack of a deep understanding of the reform epistemology and pedagogy revealed by the three former BETD graduates selected for the research. These are the teachers referred to in the first paragraph: The first teacher is Helena, a teacher at Duduva primary school, the second teacher is Kalishe, also teaching at the same school as Helena and the third teacher is Darius at Ntja Junior secondary school. The qualitative approach employed for the study served to illuminate and highlight specific issues related to the implementation of reflective practice that will be of considerable value for the researcher in her capacity as a teacher educator. These included among others: • The teacher’s need for an understanding of the key principles on which reflection is based and how to translate these into practice. • The need for teachers to have a clear understanding of the role that learners play in the reflective process. • The need to revisit the Basic Education Teacher Diploma (BETD) education programme, because for teachers to reflect they need a sound subject knowledge on which to base their judgments. These aspects, as well as the identification of the factors in the school system that contribute to the failure of reflective practice, provide a foundation for finding real solutions to the problems identified.
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  • Date Issued: 2007

Grade 5 teachers' understanding and development of concepts in social studies in selected schools in Namibia

  • Authors: Sichombe, Beatrice Sinyama
  • Date: 2007
  • Subjects: Social sciences -- Study and teaching (Elementary) -- Namibia Social science teachers -- Namibia Educational change -- Namibia Education -- Namibia
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1877 , http://hdl.handle.net/10962/d1005856
  • Description: After the introduction of Learner Centred Education in Namibia, a number of studies were conducted on how teachers either perceived learner centred education or implemented it. However, very few studies investigated the teachers' understanding of both subject matter knowledge and pedagogical content knowledge; primarily, how they understand and develop key concepts. The purpose of this study was to investigate how Grade 5 teachers' understand and develop key concepts in Social Studies in selected schools in Namibia. The study focused on three teachers in three primary schools in the Caprivi educational region of Namibia. These teachers were purposefully selected as graduates of the teacher education programme instituted at the time of the Namibian education reform process. As a teacher educator, my main motive of conducting this study was to gain a better understanding of some of the issues that have been raised about these graduates' lack of content knowledge. The study adopts a qualitative approach and seeks to investigate (a) how the three teachers in this study understand key concepts and (b) the strategies they use to develop such concepts. Three data collection instruments were employed: interviews, document analysis and class observations. The findings indicate that despite the training that all three teachers in this study received, their understanding of the concepts they taught is problematic. Furthermore, some of the strategies that the teachers used did not bring about learning with understanding. The results of the study revealed how these teachers' problems with concepts and the development of conceptual understanding are related to specific issues and can be attributed to a number of factors. Because of this, the study has provided valuable insights into aspects of teacher education that need to be addressed both in terms of in-service and pre-service programmes to support teachers in teaching for understanding, a key idea underpinning the reform process.
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  • Date Issued: 2007

Morphometrics and reproduction of Terebrasabella heterouncinata (Polychaeta:Sabellidae), infesting abalone (Haliotis midae) from different culture environments

  • Authors: Gray, Michael
  • Date: 2003
  • Subjects: Polychaeta , Sabellidae , Abalones -- Physiology , Abalones -- Nutrition , Abalone culture
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5384 , http://hdl.handle.net/10962/d1018231
  • Description: In the late 1980's abalone culturalists noticed reduced growth rate and shell deformities in some abalone stocks. These problems were the result of infestations by a shell boring polychaete, Terebrasabella heterouncinata. Under intensive abalone culture conditions the level of infestation can reach epidemic proportions and there are often severe consequences for the host abalone. Heavy sabellid infestation levels have placed the economic viability of several South African farms under threat. This study formed part of an ongoing project that is aimed at investigating the basic biology of Terebrasabella heterouncinata. The majority of abalone farmers in South Africa feed their abalone either naturally occurring kelp (Ecklonia maxima) or the formulated abalone feed, Abfeed. Farmers have suggested that the use of Abfeed is associated with higher sabellid infestation levels and changing the abalone diet from Abfeed to kelp helps reduce sabellid infestation. Speculation has arisen indicating that older, slower growing abalone are more susceptible to sabellid infestation. The effect of host abalone diet history and their growth on sabellid settlement success, morphometries and reproduction was quantified. To better understand the plasticity of the expression of life history traits the variability of morphometric and reproductive characteristics was compared between different farm environments. And more...
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  • Date Issued: 2003

Accelerated carbon dioxide deliming of cattle hides and sheepskins

  • Authors: Flowers, Karl Bernard
  • Date: 2002
  • Subjects: Tanning , Hides and skins , Carbon dioxide
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3918 , http://hdl.handle.net/10962/d1003977 , Tanning , Hides and skins , Carbon dioxide
  • Description: To avoid environmental pressure from water authorities, specifically regarding nitrogen and sulfate limits in tannery wastewater, modifications to existing deliming processes have been made. Conventional ammonium salt deliming methods contribute to Total Kjeldahl Nitrogen values in the region of 0.5 – 1.0g/L (33-67% of total TKN). Sulfate levels are increased with the use of organic deliming and ammonium sulfate deliming to the extent of 0.9g/L (27% of total sulfate). To understand the dynamics and kinetics of carbon dioxide equilibrium, the movement of carbon dioxide into deliming water, through carbonic acid, bicarbonate and ultimately into carbonates at liming or early deliming pH was studied. It was shown in this study that effective lime removal, at optimum conditions, resulted in fully delimed pelts at highly comparable quality and times compared to conventional ammonium salt deliming
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  • Date Issued: 2002

Aspects pertinent to the provision of sustainable water supply projects in the Eastern Cape Province: a case study of Nomzamo Water Supply Project

  • Authors: Mpendu, Daluhlanga Ayford
  • Date: 2002
  • Subjects: Water-supply -- South Africa -- Eastern Cape Nomzamo Water Supply Project Water-supply -- South Africa -- Social aspects
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:5952 , http://hdl.handle.net/10962/d1007450
  • Description: This study explores views behind the failure of water supply projects to achieve sustainability, primarily from the 'users' perspective, and at a secondary level from the perspective of the government/funders. One completed water supply project was selected as a case study for the research project. The overriding principle behind the water infrastructure delivery programme is that the service must be provided in a sustainable manner, and that the community must actively participate and be involved in all the phases of the project. The provision of water is not simply as it might look. In reality it is a complex process, which involves a number of organisations with different, yet important roles and responsibilities. Ongoing collaboration is important among these organisations if the service is to be provided efficiently and in a sustainable manner. In particular, local government has a Constitutional obligation to provide services to all consumers in an efficient, affordable, economical and sustainable manner. The National and Provincial governments, however, have a number of responsibilities in the field of water services. Semi-structured interview method was used to collect data from respondents. Two sets of interview schedules were developed, one for the community/water project committee members, and the other for the government officials. The data collected was analysed both qualitatively and quantitatively. This analysis enabled the researcher to draw findings, make conclusions and propose recommendations. The findings and conclusions of the study point to lack of clarity on roles and responsibilities; gender and cultural constraints; and, poor training and capacity and building of the community as being some of the reasons for the failure of the project. The recommendations proposed entail, inter alia, massive community mobilisation and awareness creation programmes; improvement in levels of the service; adoption of a gender-sensitive approach to project development; and, implementation of a training and capacity building process in the community in order to 'revitalise' the project. The study has merely focussed on one water project and sets the scene for further exploration of the subject. It certainly highlights some critical issues around sustainability of water projects, and hopefully will contribute towards the ongoing debate in this area.
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  • Date Issued: 2002

Environment as integrating organiser: a case study of curriculum 2005 in KwaMhlanga, South Africa

  • Authors: Khumalo, Four-Ten Enock
  • Date: 2001
  • Subjects: Competency-based education -- Research -- South Africa Curriculum planning -- South Africa Environmental education -- Curricula -- South Africa -- Mpumalanga Environmental education -- Curricula
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1511 , http://hdl.handle.net/10962/d1003393
  • Description: Curriculum 2005 is an attempt by the South African government to create and implement a strategic plan to change the formal school curriculum. The new curriculum has 'integration' as one of its focal features. This study is an investigation of the use of' environment' as an integrating' organiser' in the senior phase of Curriculum 2005 in a selection of schools in the Mpumalanga province. While the Curriculum 2005 framework encourages curriculum integration, this is an area which might be neglected during implementation, because there is so little experience among teachers of working in an 'integrated' way. Environmental education is an approach to education which requires and facilitates curriculum integration. This study has the potential to contribute to our understanding of the integration of environmental learning across the new curriculum. Questionnaires and vignettes based on document analysis, follow-up interviews and classroom observations, involving a small group of teachers, were used in conducting the study. The investigation has revealed that participating teachers show a limited understanding of the constructs 'environment' and 'phase organiser'. Teachers do not take or introduce a critical perspective on the nature and causes of environmental issues. They treat the construct 'environment' and associated issues quite superficially when working with learners. Participating teachers generally misunderstood the concept 'phase organisers' and tended to interpret it in concepts associated with the curriculum framework they were used to. Curriculum 2005 also requires teachers to take on a more active curriculum development role. This study looked at four teachers' attempts to develop learning programme units, and at the way in which two teachers implement their curriculum plans focussing on 'environment', in the classroom. It was found that participating teachers do not always follow the same sequence or steps when developing a learning programme. Learning programme units were not considered in developmental sequence, they lacked some form of continuity and links between intended learning outcomes and teaching activities were also lacking. There was inadequate integration between learning areas. Furthermore, integration between knowledge, skills, values and attitudes was also not quite clear among the teachers, and they tended to deal with environmental knowledge in a rather limited way, focussing instead on the awareness and attitudes. These findings are of concern, and they are in keeping with the Curriculum 2005 Review Report, which highlighted the danger of inadequate focus on curriculum content. On overall teachers seem to be struggling with the whole notion of 'integration', even though environment as a phase organiser is meant to assist with curriculum integration. The thesis ends with recommendations on how teachers might be assisted to achieve meaningful curriculum integration, through using learning outcomes as well as content knowledge relevant to environmental learning.
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  • Date Issued: 2001

The experiences of couples in relationships characterized by alcohol dependency

  • Authors: Mgilane, Nomgcobo Eunice
  • Date: 2001
  • Subjects: Alcoholism -- South Africa Alcoholics -- Family relationships Alcoholics' spouses -- South Africa Alcoholics -- South Africa -- Conduct of life
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:702 , http://hdl.handle.net/10962/d1006461
  • Description: The study focused on the expenences of Xhosa-speaking couples in relationships characterized by alcohol dependency. The goal was to generate greater understanding of the descriptions of relationship issues faced by alcohol dependent respondents and their partners. Specifically, the study focused on exploring how the alcohol dependent respondents relate to their partners, their behaviour at home when drinking prior to their admission for rehabilitation, the experiences of their partners in living with alcohol dependent partners and how they coped with the situation. In order to meet this goal, literature and empirical studies were conducted. The literature study focuses on the alcohol dependent individual's behaviour, his emotions, relapse, the family's coping strategies, alcohol and marital problems and the role of the social worker as part of the rehabilitation team. During the empirical research phase, a non-probability purposive sampling procedure was adopted. Fifteen alcohol dependent clients who were admitted for treatment and rehabilitation at Thembelitsha Rehabilitation Centre (TRC) were selected. These clients were admitted to TRC during the period starting from January 1997 to June 1999 and were discharged to their homes during the research study. To collect data, interviews were conducted separately to a total of thirty respondents. Two interview schedules were used, one for the alcohol dependent respondents (Appendix A) and the other for their partners (Appendix B). This study revealed a remarkable consistency in the descriptions of relationship issues faced by alcohol dependent respondents and their partners. These are abusive behaviours by alcohol dependent respondents. The partners were reluctant and feared challenging the behaviour. The way in which partners responded to drinking and the reactions of alcohol dependent respondents are indicative of the difficult issues faced by the couples. The study also revealed that couples experience communication, financial and sexual relationship problems. The study concludes with recommendations based on the research findings
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  • Date Issued: 2001

Capillary membrane-immobilised polyphenol oxidase and the bioremediation of industrial phenolic effluent

  • Authors: Edwards, Wade
  • Date: 1999
  • Subjects: Membranes (Technology) , Effluent quality , Pollutants , Phenols , Water -- Purification
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4095 , http://hdl.handle.net/10962/d1008458
  • Description: Waste-generating industrialisation is intrinsically associated with population and economic proliferation. This places considerable emphasis on South Africa's water shortage due to the integral relationship between population growth rate and infrastructure development. Of the various types of industry-generated effluents, those containing organic pollutants such as phenols are generally difficult to remediate. Much work has been reported in the literature on the use of enzymes for the removal of phenols from these waste-streams but little application of this bioremediation approach has reached practical fruition. This study focuses on integrating and synergistically combining the advantages of enzyme-mediated dephenolisation of synthetic and industrial effluent with that of membrane teclmology. The ability of the enzyme polyphenol oxidase to convert phenol and a number of its derivatives to chemically reactive o-quinones has been reported extensively in the literature. These o-quinones can then physically be removed from solution using various precipitation or adsorption techniques. The enzyme is, however, plagued by a product-induced phenomenon known as suicide inactivation, which renders it inactive and thus limits its application as a bioremediation tool. Integrating membrane technology with the enzyme's catalytic ability by immobilising polyphenol oxidase onto polysulphone and poly(ether sulphone) capillary membranes enabled the physical removal of these inhibitory products from the micro-environment of the immobilised enzyme which therefore increased the phenol conversion capability of the immobilised biocatalyst. Under non-immobilised conditions it was found that when exposed to a mixture of various phenols the substrate preference of the enzyme is a function of the R-group. Under immobilised conditions, however, the substrate preference of the enzyme becomes a function of certain transport constraints imposed by the capillary membrane itself. Furthermore, by integrating a quinone-removal process in the enzyme-immobilised bioreactor configuration, a 21-fold increase in the amount of substrate converted per Unit enzyme was observed when compared to the conversion capacity of the inunobilised enzyme without the product removal step. Comparisons were also made using different membrane bioreactor configurations (orientating the capillaries transverse as opposed to parallel to the module axis) and different immobilisation matrices (poly(ether sulphone) and polysulphone capillary membranes). Conversion efficiencies as high as 77% were maintained for several hours using the combination of transverse-flow modules and novel polysulphone capillary membranes. It was therefore concluded that immobilisation of polyphenol oxidase on capillary membranes does indeed show considerable potential for future development.
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  • Date Issued: 1999

An evaluation of the interdisciplinary nature of environmental education in colleges of education in Bophuthatswana

  • Authors: Akwa, Joseph Yeboah
  • Date: 1994
  • Subjects: Environmental education -- South Africa -- Bophuthatswana Environmental education -- Curricula -- South Africa -- Bophuthatswana
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1526 , http://hdl.handle.net/10962/d1003408
  • Description: This study was aimed at evaluating the interdisciplinary nature of environmental education within the colleges of education in Bophuthatswana. Data collection was based on semi-structured interviews with college lecturers and, to a lesser extent, on observations during a workshop with environmental educators from Bophuthatswana. Knowledge was gained about college related factors which influence the varying extent to which environmental education is being implemented within the colleges of education. Lecturers' understanding of the interdisciplinary nature of environmental education and related concepts was explored. Insights were also gained into problems of implementation which included lecturers' limited understanding of the concept of interdisciplinarity, structural ambiguities, limited training and experience, and a lack of clarity in both local and international literature on environmental education concepts and terms. Specifically the study sought to illuminate the dichotomy between theory and practice, the conflict between the dominant curriculum paradigm and the new emerging paradigm, and tensions between the interdisciplinary nature of environmental education and subject-based disciplines, which lead to problems of implementation. The study could make an important contribution to the current curriculum debate on environmental education in South Africa by illuminating the dichotomy between the theory and the practice of environmental education, and the problems involved in translating interdisciplinary approaches into workable classroom practices within discipline based curriculum structures.
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  • Date Issued: 1994

The geology and metallogeny of the Otavi mountain land, Damara orogen, SWA/Namibia, with particular reference to the Berg Aukas Zn-Pb-V deposit a model of ore genesis

  • Authors: Misiewicz, Julian Edward
  • Date: 1988
  • Subjects: Geology -- Namibia -- Damaraland , Ore deposits -- Namibia , Orogeny , Metallogeny , Geodynamics
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4959 , http://hdl.handle.net/10962/d1005571 , Geology -- Namibia -- Damaraland , Ore deposits -- Namibia , Orogeny , Metallogeny , Geodynamics
  • Description: The Olavi Mountain Land is a 10 000 km2 mineral province located at the eastern extremity of the exposed Northern Platform of the Damara Pan African orogenic belt. The Olavi Mountain Land is tbe most important mineral province on the Northern Platform. Exploitation of tbe Cu-Pb-Zn-V province has been on-going since the possession of the territory by the German colonial authority in 1890. Production has been mostly from four mines which in order of importance are Tsumeb, Kombat, Berg Aukas and Abeoab. A second mineral province on the Northern Platform located in the west is centred on Sesfontein where as yet only insignificant mineralization has been noted. Besides these localities, the Northern Platform is conspicuously devoid of notable mineralization. The aim of this thesis has been to document tbe Berg Aukas deposit, an important end-member type of mineralization in the Otavi Mountain Land. The basic premise bas been to show tbat the derivation and localization of the mineralization is a consequence of two broad controls which can be simply summarised as features of the basement and of the carbonate sequences. The geodynamic evolution of the Damara Belt commenced with intra-continental rifting approximately 900 Ma ago. Rift grabens trending north-east were filled by the Nosib Group which comprises mostly clastic lithologies but also some volcanics. The earliest and largest rift is referred to as the Northern Rift. Separation of the Congo, Kalahari, and proto-South American cratons resulted in rifting and rapid downwarping so that an encroaching sea and an Olavi Group carbonate shelf developed along the northern margin of the Northern Rift. Significantly, the carbonates only covered the Northern Rift in the area of the Otavi Mountain Land where a basinal dome, referred to as the Grootfontein Basement High, marked the basin edge. In the west, the carbonates covered the less important Sesfonfein Rift, and it is only in these two areas where Nosib sequences underlie the carbonate platform. Carbonate sedimentation was interrupted by a major period of crustal readjustment and the deposition of an extensive mixtite throughout the geosynclinal Swakop Trough and Northern Platform. This is referred to as the Chuos Formation and subdivides the Olavi Group into a lower Abenab and an upper Tsumeb Subgroup. Reversal of spreading led to plate collision and subduction of tbe Kalahari craton beneath the Congo craton. It was accompanied by orogenesis which resulted in F1 folding of the Northern Platform into a series of north-easterly trending intermontane basins into which a molasse sequence known as the Mulden Group was unconformably deposited. Following this major north-south deformation mild east-west compression initiated F2 folding and the formation of doubly plunging synclines. The Berg Aukas Syncline represents a primary depositional basin which was subsequently folded. The original basin was formed by late Nosib rifting wben spreading caused the Swakop geosynclinal Trough to form. Carbonates of the basal Berg Aukas Formation were deposited in a lagoonal setting typified by reef and fore-reef facies witb peri-platform conditions. Rapid subsidence caused these sediments to be overlain by deep water carbonates of the Gauss Formation. Two styles of mineralization known as the Tsumeb-type and Berg Aukas-type are stratigraphically, isotopically, and mineralogically distinct. The Tsumeb-type is a cupriferous variety of discordant bodies confined to the upper sequences beneath the Mulden unconformity. The Berg Aukas-type is a Zn-Pb variety confined to tbe basal unconformity. The Berg Aukas deposit comprises three ore bodies known as the Northern Ore Horizon, the Central Ore Body, and the Hanging Wall Ore Body. Sphalerite and galena constitute the bypogene ore. Willemite, smithsonite, cerussite, and descloizite are important supergene ores. A review of genetic models concludes that a magmatic origin initially proposed for tbe Tsumeb deposit is entirely rejected and a basin dewatering model in line with Mississippi Valley-type deposits is proposed. The syntectonic nature of mineralization at Berg Aukas and elsewhere in the Otavi Mountain Land indicates that orogenesis encouraged dewatering and leaching of metals from a broad mineralizing front along the margin of the Swakop Trough. These were transported by acidic saline brines which migrated along the clastic aquifers and structural conduits provided by the Northern Rift. Fluid inclusion studies indicate that the hydrothermal fluids at Berg Aukas were very saline (23% TDS) and were transported at temperatures ranging between 92° to 210°C. Hydrothermal fluids which mineralized Berg AukaS-type deposits migrated along the basal unconformity towards the basement high and were responsible for hydrothermally altering the basement granites and gabbros and the Nosib clastic rocks. Tsumeb-type deposits resulted by migration of fluids through the carbonate pile and along north-easterly trending basement geofractures. As a consequence of variation in transport, the Berg Aukas-type and Tsumeb-type fluids leached different sources and therefore derived mineralogically and isotopically seperable characteristics. The localization of the Berg Aukas ores was controlled by the carbonate stratigraphy and structure. Hydrothermal karsting and ore deposition took place on the contact between Massive Grey and Light Grey Dolostones which represents a permeability contrast. The movement of the hydrothermal fluids was controlled by north-south trending vertical fractures caused by F2 folding which resulted in a peric1inal structure. Hydrothermal karsting was accompanied by ca1citic, dolomitic and silicic alteration. The heated acidic fluids initiated solution collapse and a variety of breccia types. Supergene processes resulted in oxidation and upgrading of the ore. Vanadium derived indirectly from gabbros in the basement complex were transported as calcium metavanadate complexes and deposited on contact with the oxidizing base metal sulphides.
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  • Date Issued: 1988

Heterotrophic carbon dioxide fixation by Euglena

  • Authors: Peak, Jennifer Grace
  • Date: 1978
  • Subjects: Euglena
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5824 , http://hdl.handle.net/10962/d1007650
  • Description: Heterotrophic (dark, non-photosynthetic) carbon dioxide fixation was measured in the phytoflagellate Euglena gracilis. Variation in heterotrophic carbon dioxide fixation depends on the phase of batch growth and the mode of nutrition. A sharp increase in heterotrophic carbon dioxide fixation occurs during the mid- to late-logarithmic growth periods in Euglena growing photoautotrophically (with carbon dioxide as carbon source, light as energy source) and heterotrophically (in the dark with glucose as sole carbon and energy source). Cells growing heterotrophically with acetate or ethanol as sole carbon source do not increase their heterotrophic carbon dioxide fixation during the growth cycle. Addition of acetate to cultures of Euglena causes a reduction in dark carbon dioxide fixation. The results are consistent with the hypothesis that heterotrophic carbon dioxide fixation in Euglena functions in anaplerotic replenishment of the tricarboxylic acid cycle. The regulation of these changes in heterotrophic carbon dioxide fixation was shown to be controlled by exogenous ammonium in a complex fashion. Ammonium stimulates heterotrophic carbon dioxide fixation after a period of ammonium deprivation. The kinetics of the regulatory effects of the ammonium ion on dark carbon dioxide fixation are presented. A survey into the activities of carboxylating enzymes from both autotrophically and heterotrophically grown Euglena was conducted. The heterotrophic cultures were supplied with either glucose or acetate as substrate. PEP carboxykinase (E.C.4.1.1.38) and (E.C.4.1.1.49) could not be detected in any of the cultures tested. A trace amount of PEP carboxykinase (E.C.4.1.1.32) is present in the acetate grown cells only and a trace amount of pyruvate carboxylase (E.C.6.4.1.1.) is present in the glucose grown cells only. Malate enzyme (E.C.1.1.1.40), PEP carboxylase (E.C.4.1.1.31) and acetylcoenzyme A carboxylase (E.C.6.4.1.2) are present in all cells tested. Ammonium stimulation causes a small increase in specific activity of all the enzymes except acetyl-CoA carboxylase. The largest increase occurs in PEP carboxylase, but the increase is not sufficient to account for observed increases in whole cell dark carbon dioxide fixation after ammonium stimulation. Two isoenzymes of PEP carboxylase were purified from each other from both ammonium stimulated and non-stimulated cells. There are no significant differences between elution profiles of isoenzymes from ammonium stimulated and control cells. There are no significant differences between elution profiles of isoenzymes from autotrophic and heterotrophic cells. The kinetics of the regulation of the two isoenzymes by malate, citrate, succinate and 3-phosphoglycerate are presented. The products of heterotrophic carbon dioxide fixation by ammonium stimulated and control cells were identified and measured by chromatography. Ammonium stimulates the biosynthesis of glutamine, glycine, serine and alanine.
  • Full Text:
  • Date Issued: 1978

The spectrochemical determination of certain minor trace elements in plant material

  • Authors: Eve, Desmond John
  • Date: 1961
  • Subjects: Trace elements Spectrum analysis Plants -- Analysis Plants -- Effect of trace elements on Trace elements in agriculture
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4469 , http://hdl.handle.net/10962/d1011773
  • Description: A study has been made of three organic complexing reagents , namely dithizone, oxine and cupferron with a view to developing suitable methods for the separation and concentration of Zn, Co, Ni, Pb, Cu, Mn, Ti , V and Mo prior to the spectrometric determination of their concentrations. In particular the influence of pH on the chloroform extraction of ditihizonates, oxinates and cupferrates from aqueous tartrate and citrate solutions and the separation of iron by oxine extraction has been investigated. The development of a method for the chemical concentration and spectrcgraphic determination of Zn, Co, Ni, Pb, Ti, V and Mo is described and the possibility of determining Nn and Cu flame photometrically as part of the analysis scheme is demonstrated. A specially designed slide rule for the calculation of spectrographic results is described. A direct reading spectrometric method for the determination of Zn, Pb and Cu in plant material is presented. The analysis of plant ash for zinc using the 2138 . 6A spectrum line has been studied and a simple, rapid analysis method is described.
  • Full Text:
  • Date Issued: 1961

The teaching of the Acts of the Apostles concerning the Holy Spirit

  • Authors: Woods, B J
  • Date: 1955
  • Subjects: Bible. Acts , Holy Spirit
  • Language: English
  • Type: Thesis , Bachelor , BDiv
  • Identifier: vital:1281 , http://hdl.handle.net/10962/d1013453
  • Description: There must be certain reasons why one embarks on a study of the Holy Spirit. The first is perhaps because there is a need today for a Biblical doctrine of the Spirit. The second follows from the first, for there is a need for a deeper knowledge of the Spirit and His work. He is the life-giving Spirit, and we need today to be spiritually alive. The third reason for a study of this kind is that we need a deeper understanding of the power of the Spirit in the affairs of men in the world. We have got away from the idea that God works amongst us through His Spirit, and we tend to think more and more of the achievements of man, and the power of the machine to do as we wish. We need to return to the power of the Spirit, and to be instruments of God's wishes. Finally, our Christianity today, in this country, appears to be so lifeless, so stuck in the groove of routine - the interminable bazaars, money raising efforts, and social half-hours - that we have lost the enthusiasm of first century Christianity, the driving force of the Spirit spurring us on to bring the Gospel of Life to the hungry world. We need in our modern experience and our modern condition, to find the powerful enthusiasm, as a result of the Spirit' s working in us, that the early Christians found when they were filled with Him and worked under His guidance. So we undertake the study of the Spirit among the early Church, in the hope that we too may desire to be filled as the Apostles were filled.
  • Full Text:
  • Date Issued: 1955

Some measurements of the conductivities of dilute potassium chloride solutions

  • Authors: Faure, Abraham
  • Date: 1954
  • Subjects: Potassium chloride
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4471 , http://hdl.handle.net/10962/d1011787
  • Description: A constant temperature room has been constructed in which the thermoregulator is controlled by a temperature-sensitive resistance. A thermostat has been constructed in which the 0 temperature is controlled to within 0.001°C. A precision conductance bridge has been built in a very convenient form. Improvements include the replacement of the telephone as null detector by a cathode ray oscilloscope, and the use of a resistance-capacity phase-shift oscillator, which gives a good wave-form. An automatic recycling conductance water still has been built which regularly gives water with a conductivity less than 0.09 micromhos per cm. The conductivities of dilute KCl solutions have been measured, taking special care to prevent errors due to the adsorption of KCl on the surface of glass. Two cells were used for these measurements : a modified Jones cell, and a special conductimetric titration cell. The modified Jones cell has given results in good agreement with the generally-accepted values. The results of the conductimetric titration cell do not agree well with the generally-accepted values; the greatest difference (for the most dilute solution) is 0.4%. The reason for this is not known.
  • Full Text:
  • Date Issued: 1954

East London: its foundation and early development as a port

  • Authors: Gordon, B C
  • Date: 1932
  • Subjects: Smith, Harry George Wakelyn, Sir, 1788-1860 D'Urban, Benjamin, Sir, 1777-1849 Harbors -- South Africa -- East London East London (South Africa) -- History -- 1836-1866
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2606 , http://hdl.handle.net/10962/d1012046
  • Description: The flourishing city of East London has received but scant attention from historians. Its importance has been overshadowed by that of Cape Town, Durban and Port Elizabeth, each with a foundation bordering on the romantic. The introduction to this thesis indicates traces of the existence of primitive man in these parts. The historical survey will commence with notices taken of the region by nautical and land expeditions in search of either shipwrecked sailors, or news of native races. The first serious notice of East London taken by the white people came in the time of Sir Benjamin D'Urban who sought a seaport for his new province of Queen Adelaide. Our port was opened in 1836 under the appellation of Port Rex, but faded into temporary insignificance, almost oblivion, with the reversal of Sir. B. D'Urban's frontier policy by Lord Glenelg and the abandonment of the new province in 1837. It was not destined to remain forgotten, for Sir Harry Smith at the end of 1847, saw in the mouth of the Buffalo River the same possibilities as had struck the advisers of Sir B. D'Urban. To him it was the future London of the East, and the connecting link between British Kaffraria and the world outside. From that time East London has grown steadily, and of recent years very rapidly. It is not proposed to carry this survey much beyond 1866 in which year British Kaffraria was annexed to the Cape Colony.
  • Full Text:
  • Date Issued: 1932
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