Structural controls of gold mineralisation in Seguelen pit of Siguiri gold mine, Guinea
- Authors: Beavogui, Massa
- Date: 2015
- Subjects: AngloGold Ashanti Ltd. , Gold mines and mining -- Guinea -- Siguiri (Region) , Geochemical surveys -- Guinea -- Siguiri (Region) , Geology, Structural -- Guinea -- Siguiri (Region) , Faults (Geology) -- Guinea -- Siguiri (Region) , Folds (Geology) -- Guinea -- Siguiri (Region) , Turbidites -- Guinea -- Siguiri (Region) , Metamorphism (Geology) -- Guinea -- Siguiri (Region) , Hydrothermal alteration -- Guinea -- Siguiri (Region)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5091 , http://hdl.handle.net/10962/d1019879
- Description: The present study provides the results of detailed mapping and analysis of structures encountered in Seguelen pit of Siguiri gold mine, Guinea, where the Siguiri mine is geo-tectonically located in the Baoulé-Mossi domain of Man Shield in West African craton. The gold deposit is hosted in low-grade metamorphic sediments of turbidites sequences which form part of the Lower Proterozoic of Birimian Super group. Three rock formations of Balato, Fatoya and Kintinian underlay the overall pits. The Siguiri gold mine is characterized by the deep weathering profile, developed over the rocks reaching 200 m below the surface in some areas and often capped by the lateritic gravel or duricrust. The rock formations at Seguelen area are characterised by strong bedding monotonously dipping towards SW and trending NW-SE. The lithology of the host rocks has strong control on the disseminated mineralisation throughout the deposit. Two domains of rock formations are clearly distinguished at Seguelen: Fatoya Formation(Ffm) domain ; and Kintinian Formation (Kfm) domain. The two domains are separated by a contact zone of 1.7 m wide parallel to bedding and characterised by the presence of quartz fragments as well as thinly sheeted shale and black shale. This contact zone is identified as disconformity. The major tectonic deformation which has affected the region is known as D2 corresponding to the Eburnean orogeny. The major D2 related structures is the regional thrust striking N-S over an area of 12 km long and 3 km wide and within which corridors all Siguiri gold Mine open pits are located. In the N-S trending structures, there is east-northeast shortening and north-northwest extension. There is pervasive hydrothermal alteration (carbonatization and sideritization) and supergene alteration in the all pits. The hydrothermal alteration attests the intensity of hydrothermal fluid-flow over the host rocks. The hydrothermal fluids flowed along the fractures and within the wall rocks through bedding plans to form numerous auriferous quartz veins bearing disseminated sulphides through chemical reaction between fluids and wall rocks, which are remarkable at Seguelen pit. Three quartz vein sets are distinguished at Seguelen: NNE-SSW quartz vein set NE-SW quartz vein set NW-SE quartz vein set The NE-SW and NNE-SSW quartz veins are often lenticular and associated with the bulk mineralisation.
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Structural studies on yeast eIF5A using biomolecular NMR and molecular dynamics
- Authors: Sigauke, Lester Takunda
- Date: 2015
- Subjects: Molecular dynamics , Reverse transcriptase , HIV (Viruses) , HIV infections , Eukaryotic cells , Yeast
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4547 , http://hdl.handle.net/10962/d1017927
- Description: Eukaryotic initiation factor 5A, eIF5A, is a ubiquitous eukaryotic protein that has been shown to influence the translation initiation of a specific subset of mRNAs. It is the only protein known to undergo hypusination in a two-step post translational modification process involving deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH) enzymes. Hypusination has been shown to influence translation of HIV-1 and HTLV-1 nuclear export signals, while the involvement of active hypusinated eIF5A in induction of IRES mediated processes that initiate pro-apoptotic process have inspired studies into the manipulation of eIF5A in anti-cancer and anti-diabetic therapies. eIF5A oligomerisation in eukaryotic systems has been shown to be influenced by hypusination and the mechanism of dimerisation is RNA dependent. Nuclear magnetic resonance spectroscopy approaches were proposed to solve the structure of the hypusinated eIF5A in solution in order to understand the influence of hypusination on the monomeric arrangement which enhances dimerisation and activates the protein. Cleavage of the 18 kDa protein monomer by introduction of thrombin cleavage site within the flexible domain was thought to give rise to 10 kDa fragments accessible to a 600 MHz NMR spectrometer. Heteronuclear single quantum correlation experiments of the mutated isotopically labelled protein expressed in E. coli showed that the eIF5A protein with a thrombin cleavage insert, eIF5AThr (eIF5A subscript Thr), was unfolded. In silico investigations of the behaviour of eIF5A and eIF5AThr (eIF5A subscript Thr) models in solution using molecular dynamics showed that the mutated model had different solution dynamics to the native model. Chemical shift predictors were used to extract atomic resolution data of solution dynamics and the introduction of rigidity in the flexible loop region of eIF5A affected solution behaviour consistent with lack of in vivo function of eIF5AThr (eIF5A subscript Thr) in yeast. Residual dipolar coupling and T₁ relaxation times were calculated in anticipation of the extraction of experimental data from RDC and relaxation dispersion experiments based on HSQC measurable restraints.
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Structure of the nucleus ¹¹⁴Sn using gamma-ray coincidence data
- Authors: Oates, Sean Benjamin
- Date: 2015
- Subjects: High spin physics , Nuclear structure , Nuclear shell theory , Neutron counters , Decay schemes (Radioactivity) , Coincidence circuits , Collective excitations , Anisotropy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5562 , http://hdl.handle.net/10962/d1019870
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Studies towards the development of novel antimalarial agents
- Authors: Adeyemi, Christiana Modupe
- Date: 2015
- Subjects: Antimalarials , Malaria , Drug resistance , Drug development , Enzyme inhibitors , Plasmodium
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54645 , vital:26596
- Description: Considerable efforts have been made in the modification of existing antimalarial drugs, and the support of incentive programmes have led to a drastic decrease in malaria cases reported by WHO during the past 6 years. However, the development of drug resistance threatens the eradication of this deadly disease and has prompted research on the synthesis of novel antimalarial drugs. Our research has involved the design and synthesis of novel benzylated phosphonate esters as potential 1-deoxy-D-xylose-5-phosphate reductoisomerase (DXR) inhibitors. A series of amidoalkylphosphonate esters were obtained by reacting various 3-subsituted anilines and heterocyclic amines with chloroalkanoyl chlorides and reacting the resulting chloroalkanamides with triethyl phosphite using Michaelis-Arbuzov methodology. Benzylation of the phosphonate esters afforded a series of novel N-benzylated derivatives in good yields and these compounds were fully characterised by NMR and HRMS methods. Several approaches to the introduction of a benzyl group at the C-2 position of the phosphonate ester derivatives have been explored, leading unexpectedly to the isolation of unprecedented tetrahydrofuranyl derivatives. Studies towards the preparation of potential bi-functional PfDXR / HIV-1 RT inhibitors have also been initiated. Preliminary in silico docking studies of selected non-benzylated and benzylated phosphonated derivatives into the Pf-DXR active-site has provided useful insight into the binding potential of these ligands. Bioassays have revealed a very low toxicity for all the synthesised phosphonated compounds and a number of these ligands also exhibit a promising inhibitory activity against the Plasmodium parasite.
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Sunrays in a chilly winter
- Authors: Nolutshungu, Simphiwe
- Date: 2015
- Subjects: Creative writing (Higher education) -- South Africa , South African poetry (English) -- Study and teaching (Higher) , South African poetry (English) -- 21st century , South Africa -- Poetry
- Language: English , Xhosa
- Type: Thesis , Masters , MA
- Identifier: vital:5993 , http://hdl.handle.net/10962/d1017777
- Description: In both my English and IsiXhosa poetry, my themes are love, politics, and the social issues of rural communities, and include my own life experiences, both good and bad. My poems are mainly short narrative accounts of township life. Although they do have a broad educational purpose, they do not preach to the reader. In IsiXhosa, my poetic forms are influenced by the works of J J R Jolobe, W N Mbovane, P T Mtuze, and my English poems by Pablo Neruda, Mafika Pascal Gwala, Garcia Lorca and others. , Intliziyo yona izimele gxebe ifihlakele Iyimfihlo, kumagumbi omphefumlo. Iyafunxa, ifukame kulo magumbi amxinwa. Iingcango, mba! Zivaliwe! Maxa wambi zide zixel’ isisila senkukhu, sona sibonwa mhla ligquthayo. Vul’ amehlo ubaz’ iindlebe uchul’ ukunyathela. Yiza ndikubambe ngesandla, sivul’ iingcango! Masivul’ iingcango zentliziyo yam, sikrobe ngaphakathi! Masithi ntla‐ntla kumagumb’ amathathu kuphela! Masithi ntla‐ntla, kwelepolitiki yakwaXhosa, Kaloku nam ndingumXhosa! Masithi ntla‐ntla kwelifukame, i.z.i.x.i.n.g.a.x.i n.o.b.u.n.c.w.a.n.e. b.o.t.h.a.n.d.o, kaloku nam ndinemithamb’ ebalek’ igaz’ eliqhumayo! Ucango lokugqibela lukungenisa kwigumbi elinezidl’ umzi, Kaloku nam ndizalwa kulo mzi wakwaXhoooooosa! , This thesis is presented in two parts: English and isiXhosa.
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Synthesis and biological evaluation of truncated sarganaphthoquinoic acid derivatives as Hsp90 inhibitors
- Authors: Chiwakata, Maynard T
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64708 , vital:28594
- Description: Hsp90 inhibition has been at the centre of attention in current research due to the possibility of “cracking down” on the entire process leading to the development of malignant cancers. Small underlying principles common in all types of cancers have been determined that govern the transformation of normal human cells into cancerous cells, with all relying on the ATPase activity of Hsp90 protein. Hsp90 protein is therefore an attractive drug target that if successfully inhibited can result in the remission of cancer tumours by one form of treatment. To date, no Hsp90 inhibitor has been sanctioned for cancer treatment as most are still in clinical development. Our research was therefore inspired by reports that indicated the potential of quinones / naphthoquinones to act as Hsp90 inhibitors. Preliminary results of a few selected marine natural product quinone systems i.e. sargaquinoic acid (SQA) (2.47) and lapachol (3.6) showed moderate cytotoxicity and weak interactions with the Hsp90 molecular chaperone, and evidence suggested C-terminal binding of these molecules. No correlation has been determined yet between cytotoxicity and Hsp90 inhibition, hence we aimed to develop natural product inspired molecules that exhibit both cytotoxic and Hsp90 inhibition properties. Due to limited amounts of the natural product that can be acquired from natural sources, synthetic analogues were opted for. Isolation of a few selected quinones was conducted to have material that could be used in biological assays. For structural modifications, a series of truncated naphthoquinone systems were prepared adopting the sarganaphthoquinoic acid (3.5) scaffold. The naphthoquinones were prepared via Diels-Alder reactions of relevant benzoquinones with myrcene, followed by aromatization reactions using MnO2. Various alkyl and aryl amines were then coupled to the C-2/3 position of the naphthoquinone using Michael’s addition reactions. Tricyclic naphthoquinones were also synthesized from reactions with hypotaurine and citral. Design of the analogues incorporated functionalities from known Hsp90 inhibitors e.g. geldanamycin (2.28) and its analogues. Preliminary results obtained showed that coupling of naphthoquinones with aryl-amines resulted in the most cytotoxic compounds (4.14-4.19) with IC50 values as low as 0.3 μM against Hs578T breast cancer carcinoma (triple negative). Most of the alkyl amines (4.20-4.25) had IC50 values greater than 50 μM except for 4.20 and 4.21 that showed IC50 values of 7.6 μM and 2.6 μM respectively. Tricyclic naphthoquinones (4.28-4.29) showed moderate cytotoxic activity of approximately 10 μM. Hsp90 inhibition was assessed by client protein degradation assays, of which SQA (2.47), showed the best Hsp90 inhibition properties, followed by compound 4.20. The most cytotoxic arylamino-naphthoquinone (4.16) and tricyclic naphthoquinones (4.28-4.29) showed only moderate inhibition. None of the compounds led to Hsp70 induction, suggesting possible binding to the C-terminus of Hsp90. Interactions at the binding site were assessed by molecular docking studies and saturation transfer difference (STD) NMR. Docking studies were conducted on the N-terminus of Hsp90 and better binding was observed for arylamino naphthoquinones (4.14-4.19) than for other series of compounds. Unfortunately, the co-crystal structure for the C-terminus of Hsp90 is unavailable, hence docking study comparisons on both domains could not be conducted. However, STD NMR offered a platform to assess binding interactions between the naphthoquinones and the N- or C-terminal domains of Hsp90. However no interactions were observed at both the N- and C- termini of Hsp90 due to either weak binding of ligands to the protein or poor water solubility of the ligands. From these preliminary results, naphthoquinones bind to Hsp90 protein but conclusive remarks to which terminal domain they bind to could not be made. The best candidate from amongst the series of naphthoquinones prepared that showed moderate cytotoxicity and promising Hsp90 inhibition was compound 4.20. We therefore succeeded in developing a new series of naphthoquinones that possess moderate cytotoxicity and show Hsp90 inhibition.
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Synthesis of silver nanoparticles and their role against human and Plasmodium falciparum leucine aminopeptidase
- Authors: Mnkandhla, Dumisani
- Date: 2015
- Subjects: Silver , Nanoparticles , Plasmodium falciparum , Leucine aminopeptidase , Antimalarials , Nanotechnology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4150 , http://hdl.handle.net/10962/d1017911
- Description: Antimalarial drug discovery remains a challenging endeavour as malaria parasites continue to develop resistance to drugs, including those which are currently the last line of defence against the disease. Plasmodium falciparum is the most virulent of the malaria parasites and it delivers its deadliest impact during the erythrocytic stages of the parasite’s life cycle; a stage characterised by elevated catabolism of haemoglobin and anabolism of parasite proteins. The present study investigates the use of nanotechnology in the form of metallic silver nanoparticles (AgNPs) against P. falciparum leucine aminopeptidase (PfLAP), a validated biomedical target involved in haemoglobin metabolism. AgNPs were also tested against the human homolog cytosolic Homo sapiens leucine aminopeptidase (HsLAP) to ascertain their selective abilities. PfLAP and HsLAP were successfully expressed in Escherichia coli BL21(DE3) cells. PfLAP showed optimal thermal stability at 25 °C and optimal pH stability at pH 8.0 with a Km of 42.7 mM towards leucine-p-nitroanilide (LpNA) and a Vmax of 59.9 μmol.ml⁻¹.min⁻¹. HsLAP was optimally stable at 37 °C and at pH 7.0 with a Km of 16.7 mM and a Vmax of 17.2 μmol.ml⁻¹.min⁻¹. Both enzymes exhibited optimal activity in the presence of 2 mM Mn²⁺. On interaction with polyvinylpyrrolidone (PVP) stabilised AgNPs, both enzymes were inhibited to differing extents with PfLAP losing three fold of its catalytic efficiency relative to HsLAP. These results show the ability of AgNPs to selectively inhibit PfLAP whilst having much lesser effects on its human homolog. With the use of available targeting techniques, the present study shows the potential use of nanotechnology based approaches as “silver bullets” that can target PfLAP without adversely affecting the host. However further research needs to be conducted to better understand the mechanisms of AgNP action, drug targeting and the health and safety issues associated with nanotechnology use.
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Systematics and biogeography of Mesobola brevianalis (Boulenger, 1908) (Teleostei: Cyprinidae)
- Authors: Riddin, Megan Amy
- Date: 2015
- Subjects: River sardine , Molecular evolution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5930 , http://hdl.handle.net/10962/d1017808
- Description: The accurate identification of fish species, their life stages and their products enables the correct management of fisheries, research and conservation of distinctive populations for long-term survival and sustainability. Mesobola brevianalis Boulenger, 1908, commonly known as the river sardine, is found in many river systems in southern Africa. Because it exhibits widely separated populations showing subtle differences, particularly in colour, it is thought that there may be cryptic species involved. Standard phylogenetic techniques using three genetic markers (mitochondrial COI, nuclear protein RAG1 and nuclear ribosomal 28S rRNA), enabled the building of phylogenetic networks for M. brevianalis and some outgroup species. Consistent patterns of relationship were seen with 28S supporting monophyly. COI and RAG1 suggested that populations that are currently identified as M. brevianalis in fact represent several species. There was sufficiently strong support for the evolutionary independence of the M. brevianalis populations from the Rovuma, Kunene and Orange River Systems to consider them as independent species. The independence of the genus Mesobola was brought into question because Engraulicypris sardella and Rastrineobola argentea were placed within it phylogenetically.Morphometric methods in the form of multivariate truss network analyses, were performed to locate morphological markers for populations. There was little to no variation among most of the populations synonymized under M. brevianalis. Furthermore, neither latitude nor longitude had an effect on the morphological characters that might be linked to functional evolution. A molecular clock analysis of COI data was used to calibrate a paleobiogeographical model which entailed a divergence of lineages starting from an easterly reigning Paleo-Congo Basin, via a hypothetical Paleo-Kalahari Lake that was fragmented by a series of uplifts and drying events beginning ~65 million years ago. Complete evidence supported the synonymisation of the genera Engraulicypris and Mesobola, the resurrection of the species name gariepinus for the Orange River Systempopulation, and the description of two new species: E. ngalala from the Rovuma River System and E. howesi from the Kunene River System.
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Taxing the Minerals Sector in South Africa: a comparative analysis of the proposed tax model for South Africa and the models adopted in selected African countries
- Authors: Van den Berg, Jana
- Date: 2015
- Subjects: Industrial minerals -- Taxation -- South Africa , Industrial minerals -- Taxation -- Developing countries , Industrial minerals -- Law and legislation -- South Africa , Industrial minerals -- Law and legislation -- Developing countries
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:919 , http://hdl.handle.net/10962/d1017545
- Description: The State Intervention in the Minerals Sector Report emerged as a resolution during the 3rd National General Council Resolution on Economic Transformation held in 2012, during which the Council stated that: “The ANC’s approach to economic transformation of the South African economy should always be holistic and comprehensive, covering all sectors of the economy. In this regard, the ANC should ensure greater state involvement and control of strategic sectors of the economy, such as mining, energy, the financial sector and others.” It was for this reason that the National General Council mandated the National Executive Committee to ensure that further work be done on ways in which the African National Congress can implement economic transformation in sectors such as the mining industry. It was suggested that methods including research, study tours and discussions be conducted to gather the required information. As a result of the research, The State Intervention in the Minerals Sector Report emerged. In The State Intervention in the Minerals Sector Report, the mineral sectors of developed as well as developing countries are compared with each other. The developing countries compared included Botswana, Zambia, Ghana, Liberia and Sierra Leone, and these countries have also been selected for the purpose of comparison in the present research. The goal of this study is to analyse the recommendations made in The State Intervention in the Minerals Sector Report regarding State involvement in the minerals sector. To determine whether the economic situation in South Africa is comparable to the five other African countries, an analysis based on demographic indicators, the history of the minerals sector in the various countries, its contribution to the fiscal regime of that country, its economic contribution, as well as the extent of involvement from Government and the model implemented for its involvement, is conducted. According to a work paper published by the World Bank on the world development indicators for 2014, control over metal supply to the economy has been considered vital for political and economic reasons in most societies. It further states that most State-owned mining companies have over the years and, in particular, in developing countries, not been able to operate successfully, leading to privatisation. Poor performance is, however, not necessarily the reason for State ownership. Areas not addressed by this thesis include the Gold Mining industry in South Africa and the Diamond mining industry in Botswana.
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Teacher leadership : a study in a township high school
- Authors: Kumalo, Elizabeth Nomso
- Date: 2015
- Subjects: Educational leadership -- South Africa -- Eastern Cape , Teacher participation in administration -- South Africa -- Eastern Cape , Teacher effectiveness -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2038 , http://hdl.handle.net/10962/d1017349
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Teacher leadership practice : a case study of a public primary school in a semi-urban area of the Otjozondjupa Region, central Namibia
- Authors: Hanghuwo, Maria Nahambo
- Date: 2015
- Subjects: Democracy and education -- Study and teaching (Elementary) -- Namibia , Educational leadership , Teacher participation in administration
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2030 , http://hdl.handle.net/10962/d1017341
- Description: The education system in Namibia was shaped by the policies located within the framework of the apartheid ideology. Since it gained its independence in 1990, the government positioned education at the top of the national priorities. Thus, there has been a growing realisation of the importance of more democratic forms of leadership in the education system for the country to be able to cater for a democratic society. Amongst others, teachers became active creators and managers of the learning outcomes. In addition, teachers are regarded as agents of change and the driving force for productive teaching and learning. Literature describes how the management in schools has been redistributing authority and power so that a culture of teacher leadership in school communities can grow. More importantly, school improvement depends more on the active involvement of teacher leaders as it is realised that people in formal positions cannot do everything. In this line this study investigated the understanding of teachers and members of management of teacher leadership practice and it further identified the structural and cultural factors which enabled and inhibited this practice in a primary school. This study is a case study of a Primary school in a semi-urban area of Otjozondjupa Region, a central part of Namibia. This study was conducted in the interpretive paradigm and it is a qualitative case in nature, employing semi-structured interviews, observation and document analysis. Triangulation over the data revealed that respondents have an understanding of the concept and that all teachers are involved in leadership roles at school which are more strongly found in the classroom and through involvement with other teachers. Teacher leadership roles at the case study school also occur within the whole school with some limitations and also extend beyond the school. Grant’s (2008) model of teacher leadership was used to analyse the data. The study suggested some hindrances and supporting factors of teacher leadership. The findings suggested that teacher leadership is understood at the case study school and that they experienced factors that enabled and hindered this practice at different stages. Enabling factors included the school structure, further studies and workshops attended, while teacher leadership is impeded by teachers’ unwillingness to collaborate with others and the platoon system. The study recommends future large scale studies, including at secondary schools, so that a broader sense of teacher leadership may emerge.
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Teacher perceptions regarding training and their subsequent ability to integrate ICTs into marginalised rural schools : The ICT4RED Case Study
- Authors: Nkula, Kanya Zonke
- Date: 2015
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:20978 , http://hdl.handle.net/10962/5798
- Description: It is well documented that Information and Communication Technologies (ICTs) play an important role in education and that their use is associated with improving student learning and adding value to the curriculum. However, despite the opportunities that ICTs offer, numerous schools in South Africa face various barriers that result in the limited use of ICTs in the classroom. Literature has highlighted the lack of integration as one of these barriers. Teachers focus on teaching about ICTs where the focus is on developing computer literacy or technical knowledge rather than allowing students to learn through or with ICTs. This thesis aims to explore the concept of ICT integration in rural schools, where ICTs form an integral part of teaching and learning practices. It presents a number of theoretical considerations for ICT integration with a particular focus on teacher pedagogical beliefs and barriers to integration. Using interpretivism as the underlying philosophy and thematic analysis as the analysis tool, the author reflects on ICT integration in the ICT4RED project at Arthur Mfebe Senior Secondary School in the Eastern Cape Province. Furthermore, this thesis offers an in-depth understanding of integration barriers in rural marginalised schools. These barriers are presented in Thematic Maps as well as a framework which incorporates both theoretical considerations and themes that emerged from fieldwork.
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Teaching for conceptual understanding : an analysis of selected teachers' practice
- Authors: Kashima, Andreas Akwenye
- Date: 2015
- Subjects: Teacher effectiveness -- Namibia , Student-centered learning -- Namibia , Constructivism (Education) -- Namibia , Problem solving , Teachers -- In-service training -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2037 , http://hdl.handle.net/10962/d1017348
- Description: The purpose of this study was to explore how teachers’ practice either supports or constrains learners’ conceptual understanding. The study is structured within an interpretive paradigm. The research takes the form of a case study and focused on the teaching practice of two purposefully selected teachers who had been identified as being effective/successful practitioners. The data was collected in two stages. In the first stage, qualitative data was collected by video recording six classroom lessons, three for each of the two participating teachers. In stage 2, participating teachers were individually interviewed. In these interviews the two participating teachers were asked to reflect on their classroom practice, through a process of stimulated recall, where their actions seemed to either support or constrain the development of learners’ conceptual understanding. The study identified a number of elements of the two teachers’ practice that related to the development of learners’ conceptual understanding in the classroom. These include building on learners’ prior knowledge, the use of concrete manipulatives, questioning that promotes critical thinking, and the use of multiple representations and connections. The study also identified elements of the two teachers’ practice that had the potential to constrain the development of learners’ conceptual understanding. These include the lack of opportunities for co-operative or peer-oriented learning, the absence of questioning that leads to discussion, and a scarcity of activities that build mathematical concepts through hands-on engagement. The study highlights the need for supporting teachers and helping them strengthen their practice with regard to those activities that support the development of conceptual understanding in their learners.
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The acute impact of extended aerobic exercise on cognitive performance
- Authors: Tichiwanhuyi, Tendayi Stephen
- Date: 2015
- Subjects: Aerobic exercises , Cognition -- Effect of exercise on , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Visual perception , Short-term memory , Motor ability , Human information processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5173 , http://hdl.handle.net/10962/d1018182
- Description: Previous research has established a relationship between exercise and cognition, with more emphasis on this ascertained link, being made on the effects of long term and endurance exercise on cognition. However, enhanced worker effectiveness relies on a strong acute collaboration of physical and cognitive performance during task execution. As a result, the purpose of this study was to examine the acute effects of extended aerobic exercise on visual perception, working memory and motor responses, and to achieve this 24 participants (12 males and 12 females) aged between 18 and 24 participated in a 2 bout cycling exercise. The experimental condition had cycling resistance set at 60 percent of each individual’s maximum aerobic output and the control condition had zero cycling resistance, where three cognitive tasks were performed at 10 minute intervals during the cycling exercise. The results showed that exercise did not affect any significant changes on the cognitive performance measures over the entire cycling duration, as well as during the exercise phase (cycling with resistance). However, visual perception improved significantly (p<0.05) immediately after exercise. This led to the conclusion that moderate to high intensity exercise when performed for an extended duration, has selective effects on certain cognitive performance measures, with the time at which the performance is measured during the exercise being a relevant factor to be considered for maximum activation effects of the exercise.
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The associative behaviour of silky sharks, Carcharhinus falciformis, with floating objects in the open ocean
- Authors: Filmalter, John David
- Date: 2015
- Subjects: Silky shark , Silky shark -- Behavior , Silky shark -- Marking , Silky shark -- Food , Tuna fisheries -- Bycatches , Fish aggregation devices , Underwater acoustic telemetry , Fish tagging
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5381 , http://hdl.handle.net/10962/d1018177
- Description: The silky shark Carcharhinus falciformis forms the primary elasmobranch bycatch in tuna purse seine fisheries using fish aggregating devices (FADs) in all of the world’s tropical oceans. Its life-history traits of slow growth, late maturation and low fecundity make it vulnerable to over exploitation, as is apparent from historical bycatch trends. Very little is known about the associative behaviour of this species with floating objects, information which is essential in formulating effective mitigation and management measures. This study aims to address this knowledge gap through the use of various electronic tagging techniques in conjunction with dietary analysis. Dietary data were collected from 323 silky sharks incidentally caught at FADs. Approximately 40 percent of the diet consisted of prey associated with FADs while the remaining 60 percent were non-associated species of crustaceans, cephalopods and fishes. These results suggest that the associative behaviour is not primarily driven by trophic enhancement, but is likely a combination of predator avoidance, social interactions and feeding. Fine-scale behavioural data from silky sharks associated with drifting FADs were collected through the use of acoustic telemetry techniques. Acoustic tags were implanted into 38 silky sharks (69- 116 cm TL) at eight FADs. FADs were equipped with satellite linked acoustic receivers and abandoned to drift freely. Presence/absence and swimming depth data were telemetered via the Iridium satellite system. A total of 300 d of behavioural data were collected from 20 tagged individuals. Individuals remain associated with the same FAD for extended periods (min = 2.84 d, max = 30.60 d, mean = 15.69 d). Strong diel patterns were observed in both association and swimming depth. Typically individuals moved away from FADs after sunset and return later during the night, then remain closely associated until the following evening. Vertical behaviour also changed around sunset with sharks using fairly constant depths, within the upper 25 m, during the day and switching to rapid vertical movements during the night, with dives in excess of 250 m recoded. Broader scale movement behaviour was investigated using pop-up archival satellite tags (PSATs). Tags were deployed on 46 silky sharks (86-224.5 cm TL) for a total of 1495 d. Light data were used to calculate geolocation estimates and reconstruct the sharks’ trajectories. Movement patterns differed between animals and according to deployment duration. Several extensive horizontal movements were observed, with an average track length of 3240 km during an average tag deployment of 44.02 d. Horizontal movement patterns were found to correlate very closely with drift patterns of FADs. Consequently, it appears that the movement behaviour of juvenile silky sharks is strongly influenced by the movement of drifting FADs in this region. Ghost fishing of silky sharks through entanglement in FADs was also investigated using data derived from PSATs as well as underwater visual censuses. Thirteen per cent of the tagged sharks became entangled in FADs and entangled sharks were observed in 35 percent of the 51 FADs surveyed. Using this information in conjunction with estimated time that sharks remained entangled in the FAD (from depth data from PSATs), and scaling up according to estimates of FAD numbers, it was found that between 480 000 and 960 000 silky sharks are killed annually in this manner in the Indian Ocean. Subsequent management measures in this region prevent the deployment of FADs with netting that could lead to entanglement. Overall, floating objects appear to play a significant role in the juvenile life stages of silky sharks in this region. While their association with floating objects is clearly advantageous in an evolutionary sense, under current tuna fishery trends, this behaviour is certainly detrimental for the population.
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The barefoot road
- Authors: Dingle, Brian Clinton
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5989 , http://hdl.handle.net/10962/d1017773
- Description: My novella is set in South Africa in a post-apocalyptic world. The drone technology theorised for the near future is widespread and scattered survivors live under the constant threat of drone strikes. The protagonist tries to negotiate these dangers and the looming threat of a slave empire to reconnect with his friends and family. He encounters bizarre hallucinations and flashbacks as a result of exposure to an unidentified gas.
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The biology, behaviour and survival of pupating false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a citrus pest in South Africa
- Authors: Love, Claire Natalie
- Date: 2015
- Subjects: Cryptophlebia leucotreta -- South Africa , Cryptophlebia leucotreta -- Larvae -- Behavior , Citrus -- Diseases and pests , Citrus -- Diseases and pests -- Biological control , Biological pest control agents , Entomopathogenic fungi , Insect nematodes , Pupae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5941 , http://hdl.handle.net/10962/d1018907
- Description: Control of the citrus pest, false codling moth (FCM), Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) is crucial for the South African citrus industry. The economic losses and phytosanitary status of this pest, coupled with increased consumer awareness and demands, has created a need for effective, IPM-compatible control measures for use against the soil-dwelling life stages of FCM. Promising developments in the field of microbial control through the use of entomopathogenic fungi (EPF) and entomopathogenic nematodes (EPNs) have highlighted the need for research regarding pupation biology, behaviour and survival of FCM, as a good understanding of biology of the target organism is an important component of any biological control programme. The aim of this study was to improve the current understanding of FCM pupation habits through the manipulation of soil texture class, ground cover, shading, soil compaction, air temperature, and soil moisture in the laboratory. These findings would then be used to aid the biological control programmes using EPF and EPNs against FCM in the soil. Three soil texture classes (sandy loam, silt loam and silty clay loam) were obtained from orchards for use in the study. FCM larvae were allowed to drop into the soil of their own accord and the pupation behaviour that followed was then captured on film with pupae formed in the soil being kept in order to measure adult eclosion. In general, very few abiotic factors had a clear influence on FCM pupation. Larval wandering time and distance was short, but also variable between individuals. Distance did increase when soils were moist. Pupation depth was shallow, with pupal cocoons generally being formed on the soil surface. Depth of pupation was less than one centimetre for all abiotic conditions, with little burrowing into soil. Eclosion success was higher for sandier soils when these were dry and uncompacted, but the addition of both moisture and soil compaction increased FCM eclosion success. FCM was sensitive to desiccation when the soils were dry and temperature limits of 15 °C and 32 °C had a strongly negative impact on eclosion success. Preferences for particular abiotic conditions were limited to only certain moisture conditions when interacting with soil texture class and a preference for pupating in soil when it is available. Limited preference was found for particular soil textures despite this having a strong influence on eclosion success, but individuals did appear to pupate in close proximity to one another. Viable direct habitat manipulation for FCM control could not be identified. These results and all of the abiotic variables measured have important implications for EPF and EPN application, survival and persistence in the soil in order to improve the ability of these biological control agents to control FCM. These are discussed in each chapter.
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The black and its double : the crisis of self-representation in protest and ‘post’-protest black South African fiction
- Authors: Kenqu, Amanda Yolisa
- Date: 2015
- Subjects: Serote, Mongane Wally, 1944- -- Criticism and interpretation , Duiker, K. Sello -- Criticism and interpretation , Matlwa, Kopano -- Criticism and interpretation , Black people in literature , Race in literature , Protest literature, African (English) , Mimesis in literature , Black people -- Race identity -- South Africa , Serote, Mongane Wally, 1944- -- To every birth Its blood , Duiker, K. Sello -- Thirteen cents , Matlwa, Kopano -- Coconut
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2331 , http://hdl.handle.net/10962/d1020835
- Description: This study explores the crisis of representation in black South African protest and ‘post’-apartheid literature. Conversant with the debates on the crisis of representation in black South African protest literature from the 1960s to the late 1980s, the dissertation proposes a re-reading of the ‘crisis’ by locating it in the black writer’s struggle for an aesthetic with which to express the existential crisis of blackness. I contend that not only protest but also contemporary or ‘post’-protest black South African literature exhibits a split or fractured mode of writing which is characterised by the displacement/unheimlichheid produced by colonialism and apartheid, as well as by the contentious nature of that which this literature endeavours to capture – the fraught identity of blackness. In my exploration of the split or double narratives of Mongane Serote’s To Every Birth Its Blood, K. Sello Duiker’s Thirteen Cents, and Kopano Matlwa’s Coconut, I examine the representation of blackness through the themes of violence, trauma, powerlessness, failure, and unhomeliness/unbelongingness – all of which suggest the lack of a solid foundation upon which to construct a stable black identity. This instability, I ultimately argue, suggests a move beyond an Afrocentric perspective on identity and traditional tropes of blackness towards a more processual, fluid, and permeable post-black politics.
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The call centre labour process : a study of work and workers’ experiences at Joburg Connect, South Africa
- Authors: Magoqwana, Babalwa Mirianda
- Date: 2015
- Subjects: Johannesburg (South Africa) -- Joburg Connect , Call center agents -- South Africa -- Johannesburg -- Case studies , Work environment -- South Africa -- Johannesburg -- Case studies , Customer services -- South Africa -- Johannesburg -- Case studies , Personnel management -- South Africa -- Johannesburg -- Case studies , Employee morale -- South Africa -- Johannesburg -- Case studies , Employees -- Attitudes -- Case studies , Municipal services -- South Africa -- Johannesburg -- Case studies , South Africa -- Economic conditions -- 1991- , South Africa -- Politics and government -- 1994- , South Africa -- Social conditions -- 1994-
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3400 , http://hdl.handle.net/10962/d1018569 , Johannesburg (South Africa) -- Joburg Connect , Call center agents -- South Africa -- Johannesburg -- Case studies , Work environment -- South Africa -- Johannesburg -- Case studies , Customer services -- South Africa -- Johannesburg -- Case studies , Personnel management -- South Africa -- Johannesburg -- Case studies , Employee morale -- South Africa -- Johannesburg -- Case studies , Employees -- Attitudes -- Case studies , Municipal services -- South Africa -- Johannesburg -- Case studies , South Africa -- Economic conditions -- 1991- , South Africa -- Politics and government -- 1994-
- Description: This thesis is an investigation of the call centre labour process focusing on both the way work is organised and experienced by the operators and the management of employee relations inside a local government workplace – The City of Johannesburg (COJ) Call Centre. The City of Johannesburg is used to understand labour process dynamics in local government. Johannesburg was recently named the ‘World’s Second Most Inspiring City’ (by Global City Index, 2014) possessing economic and political influence within and around South Africa. Johannesburg is the economic hub of the country, contributing nine per cent to the South African GDP. But it needs to be emphasised that the focus of this thesis is on the labour process rather than the City of Johannesburg. The nature of work in the COJ local government call centre involves answering calls about water, electricity, refuse removal, accounts and other general municipal services. The government’s objective was to have a more customer centred service delivery plan in compliance with the Batho Pele (People first) framework (RSA, 1997, White Paper on Local Government). This resulted in a shift in the government ‘mantra’ and philosophy from viewing Johannesburg residents as customers rather than citizens. This shift from public administration to New Public Management (NPM) has meant the introduction of private sector business principles into public services. This seeks to improve organisational and individual performance to enhance service delivery within South African municipalities. This is also meant to promote responsive and performance management culture. The study uses Labour Process Theory set out in Labour and Monopoly Capital (LMC-1974) by Harry Braverman to argue for the need to contextualise the labour process debate within the socio-political understanding of work in South Africa. In developing the argument about the narrow analysis of public sector call centres based on economic lines I have reviewed literature on call centres which is influenced by Michel Foucault and Harry Braverman to understand the public sector call centre labour process. Inspired by Adesina (2002) and Mafeje (1981) this study uses a ‘complementarity’ approach to knowledge. This means the local context tends to complement the global trends though not without contradictions within the local context. The case study approach was used for in-depth analysis of the local context through different methods (semi-structured interviews, focus group discussions, observations and survey questionnaires) to collect data from different stakeholders within the City of Johannesburg between 2010 and 2013. The concept of a ‘(dis)connecting city’ is fitting for the COJ as this city connects the rest of Sub-Saharan Africa and South Africa to the world through its commerce and political influence. Based on the challenges experienced in this local government call centre I attempt to show the the politicised nature of the public sector call centre labour process. I use the differential power relations in the frontline between customer and Joburg connect workers to illustrate this point. The lack of emphasis on the politicised nature of public sector call centres within literature is informed by the de-contextualised nature of these call centres. In the end, I argue that public sector call centre labour process is multilayered, contradictory and complicated because of these workers’ role as citizens, customers, community members and service providers from a politicised community environment.
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The cheetahs of the Northern Tuli Game Reserve, Botswana: population estimates, monitoring techniques and human-predator conflict
- Authors: Brassine, Eleanor I
- Date: 2015
- Subjects: Cheetah -- Botswana , Northern Tuli Game Reserve , Animal populations -- Botswana
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5922 , http://hdl.handle.net/10962/d1017800
- Description: Remaining viable cheetah (Acinonyx jubatus) populations in Africa are threatened by direct persecution through conflict with farmers and habitat degradation and fragmentation. Botswana is considered a stronghold for free roaming cheetahs in Africa, yet the country has had relatively limited research on its cheetahs, and information from the east of the country is lacking. Data on the current status of populations is thus required to make informed management decisions. My study provides estimates of population density, abundance, distribution and status for the demographically open cheetah population of the Northern Tuli Game Reserve (NOTUGRE) in Botswana. The effectiveness of two population monitoring methods, namely camera trapping and a photographic survey, were also investigated. Moreover, I report on the level of conflict between livestock farmers and predators on rural communal farmlands within and adjacent to NOTUGRE. Data were collected between May 2012 and November 2013. Results indicate a low population density of 0.61 ± 0.18 adult cheetahs per 100 km² and a minimum population size of 10 individuals (nine adults and one cub). Camera traps placed at cheetah scent-marking posts increased detection rates and provided ideal set up locations. This approach, together with Spatial Explicit Capture- Recapture (SECR) models, is recommended for future studies. The long-term studies that are required to better understand the status of cheetahs in Botswana do not exist. Thus, photographic surveys may provide an alternative method for providing baseline data on population numbers, distribution and demography. The third aspect of my study gathered information on levels of livestock loss and human tolerance of predators through the use of interviews (n = 80). Conflict with subsistence farmers is a concern as livestock depredation is relatively high (9.1% of total livestock owned) and farmers had an overall negative attitude towards conservation of large predators. My results suggest that human-predator conflict in this area is more complex than the direct financial loss from depredation. Hence, reducing depredation rates alone is unlikely to change farmer tolerance of wildlife on farmlands. Improved, responsible farm management, including self-responsibility for livestock rearing, and positive appreciation for wildlife are necessary. The NOTUGRE cheetah population requires further research to understand possible threats to the population. Furthermore, a better understanding of the connectivity between cheetahs of NOTUGRE, South Africa and Zimbabwe is required. The number of cheetahs within NOTUGRE is too small to sustain a viable population, hence conserving cheetahs outside of the protected area should be a priority for the conservation of the population. This can only be achieved through assistance and involvement from national authorities, local people and conservation organisations.
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