Home range dynamics of spotted grunter, pomadasys commersonnii, in a South African intermittently open estuary
- Authors: O'Connell, Bronwyn Anne
- Date: 2008
- Subjects: Grunts (Fishes) -- South Africa -- Eastern Cape , Pomadasys -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Estuarine fishes -- South Africa -- Eastern Cape , Estuarine fishes -- Habitat -- South Africa -- Eastern Cape , Fishery management -- South Africa -- Eastern Cape , Fishes -- Home range , Fishes -- Home range -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5286 , http://hdl.handle.net/10962/d1005130 , Grunts (Fishes) -- South Africa -- Eastern Cape , Pomadasys -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Estuarine fishes -- South Africa -- Eastern Cape , Estuarine fishes -- Habitat -- South Africa -- Eastern Cape , Fishery management -- South Africa -- Eastern Cape , Fishes -- Home range , Fishes -- Home range -- South Africa -- Eastern Cape
- Description: The spotted grunter (Pomadasys commersonnii) is an important, estuarine-dependent, fishery species in southern Africa. Since estuaries are essential habitats in the life history of this species, the quantification of area use patterns and movements is important for fisheries management. In this study, acoustic telemetry was used to investigate movements, use of habitat and home range dynamics of spotted grunter in the small intermittently open East Kleinemonde Estuary on the Eastern Cape coast of South Africa. Nine spotted grunter (range: 326-489mm TL) were surgically equipped with uniquely coded acoustic transmitters. Positional fixes were obtained by manual tracking tagged individuals on six days and six nights during five tracking sessions from March to November 2004. In addition, five stationary data-logging receivers, moored at specific locations from the mouth to the top of the estuary provided additional long-term monitoring. Kernel home ranges (95% UD) varied in size (26 296-165 321m²) but were all located in a common high use area situated between 300-1 300m from the estuary mouth, which coincided with the highest abundance of prey items. There was no significant variation in home range size [C² (N = 9, df = 4) = 4.18; p = 0.38] between the temporally segregated tracking sessions (over nine months). The persistence of these home range estimates were confirmed by the long-term data-logging receivers. There was no significant diel variation in home range size [F(4, 64) = 0.05, p = 0.99] or core area size [F(4, 64) = 1.40, p = 0.25]. Fish length showed negative, although not significant, relationships between home range size (p = 0.225); number of home range areas (p = 0.065); core area size (p = 0.512) and home range length (p = 0.320). Use of habitat and home range dynamics of spotted grunter in the East Kleinemonde Estuary were consistent over the nine month study period, and they appeared to be influenced more by biotic than abiotic factors. However, when the mouth opened at the end of the study, most tagged fish vacated their home ranges and emigrated to sea.
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Importance of various data sources in deterministic stock assessment models
- Authors: Northrop, Amanda Rosalind
- Date: 2008
- Subjects: Fish stock assessment -- Mathematical models , Fishery management -- Mathematical models , Fish populations -- Mathematical models , Error analysis (Mathematics) , Fishery management -- Statistical methods , Fish stock assessment -- Statistical methods
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5571 , http://hdl.handle.net/10962/d1002811 , Fish stock assessment -- Mathematical models , Fishery management -- Mathematical models , Fish populations -- Mathematical models , Error analysis (Mathematics) , Fishery management -- Statistical methods , Fish stock assessment -- Statistical methods
- Description: In fisheries, advice for the management of fish populations is based upon management quantities that are estimated by stock assessment models. Fisheries stock assessment is a process in which data collected from a fish population are used to generate a model which enables the effects of fishing on a stock to be quantified. This study determined the effects of various data sources, assumptions, error scenarios and sample sizes on the accuracy with which the age-structured production model and the Schaefer model (assessment models) were able to estimate key management quantities for a fish resource similar to the Cape hakes (Merluccius capensis and M. paradoxus). An age-structured production model was used as the operating model to simulate hypothetical fish resource population dynamics for which management quantities could be determined by the assessment models. Different stocks were simulated with various harvest rate histories. These harvest rates produced Downhill trip data, where harvest rates increase over time until the resource is close to collapse, and Good contrast data, where the harvest rate increases over time until the resource is at less than half of it’s exploitable biomass, and then it decreases allowing the resource to rebuild. The accuracy of the assessment models were determined when data were drawn from the operating model with various combinations of error. The age-structured production model was more accurate at estimating maximum sustainable yield, maximum sustainable yield level and the maximum sustainable yield ratio. The Schaefer model gave more accurate estimates of Depletion and Total Allowable Catch. While the assessment models were able to estimate management quantities using Downhill trip data, the estimates improved significantly when the models were tuned with Good contrast data. When autocorrelation in the spawner-recruit curve was not accounted for by the deterministic assessment model, inaccuracy in parameter estimates were high. The assessment model management quantities were not greatly affected by multinomial ageing error in the catch-at-age matrices at a sample size of 5000 otoliths. Assessment model estimates were closer to their true values when log-normal error were assumed in the catch-at-age matrix, even when the true underlying error were multinomial. However, the multinomial had smaller coefficients of variation at all sample sizes, between 1000 and 10000, of otoliths aged. It was recommended that the assessment model is chosen based on the management quantity of interest. When the underlying error is multinomial, the weighted log-normal likelihood function should be used in the catch-at-age matrix to obtain accurate parameter estimates. However, the multinomial likelihood should be used to minimise the coefficient of variation. Investigation into correcting for autocorrelation in the stock-recruitment relationship should be carried out, as it had a large effect on the accuracy of management quantities.
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Information and communication technology driven teaching and learning opportunities in support of environmental education processes: a case of the eno-environment online programme at Treverton Preparatory School, South Africa
- Authors: Snow, Janet P
- Date: 2008
- Subjects: Treverton School (Natal, South Africa) , Environmental education -- South Africa -- Case studies , Sustainable development -- South Africa -- Case studies , Computer-assisted instruction -- South Africa -- Case studies , Education, Preschool -- Computer assisted instruction -- South Africa -- Case studies , Education, Preschool -- South Africa -- Case studies , Early childhood education -- South Africa -- Case studies , Educational technology -- South Africa -- Case studies , Ethnoscience -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1575 , http://hdl.handle.net/10962/d1003457 , Treverton School (Natal, South Africa) , Environmental education -- South Africa -- Case studies , Sustainable development -- South Africa -- Case studies , Computer-assisted instruction -- South Africa -- Case studies , Education, Preschool -- Computer assisted instruction -- South Africa -- Case studies , Education, Preschool -- South Africa -- Case studies , Early childhood education -- South Africa -- Case studies , Educational technology -- South Africa -- Case studies , Ethnoscience -- Study and teaching -- South Africa
- Description: This research looks at a global virtual web-based programme for environmental awareness and education for sustainable development (ENO-Environment Online). It is a case study of Treverton Preparatory school in South Africa, one of several schools where the programme is implemented. One of the themes within the programme (“This is our culture”) is highlighted. A mixed method, interpretive case study methodology is used. Research methods include two focus group interviews with a selected group of learners, observations of four computer-based lessons and one practical session, document analysis of the three forms of learners’ submissions (‘blog’ site submission, presentation of material and ‘chat’ session), and two interviews conducted with the Treverton form teacher and ENO programme co-ordinator. The research views the Treverton ENO activities in relation to: academic rigour in Information and Communication Technology (ICT) use, the teacher’s role in ICT pedagogy, and active learning in ICT applications. As the theme is culturally based with a global perspective, the research also considers these activities from the perspectives of education for cultural knowledge (multicultural education) and in terms of mobilising indigenous knowledge and global education. These perspectives on the ENO activities are analysed in relation to dimensions of teaching and learning guidelines pertinent to Education for Sustainable Development in a southern African context. The research shows that the ENO theme supported a variety of learning contexts, a sense of community, modelling of behaviours and actions, debate, sharing of information and improved communication skills. Learners were exposed to cultural diversity, contradictory cultural values, cultural and global inclusivity. Knowledge of social cultural practices and indigenous knowledge was shared. Academic rigour in the ENO theme was noted with reflection being the predominant activity. Based on these key findings, recommendations to the ENO programme, schools and teachers have been made. These include: exploring possibilities for increasing focus on sustainable development actions, improving access to relevant information, encouraging critical debate and critical engagement with cultural diversity.
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Information and communication technology in A-level physics teaching and learning at secondary schools in Manicaland Zimbabwe: multiple case studies
- Authors: Mlambo, Watson
- Date: 2008
- Subjects: Information technology -- Zimbabwe Educational technology -- Zimbabwe Education, Secondary -- Zimbabwe Information technology -- Study and teaching (Secondary) -- Zimbabwe Physics -- Study and teaching (Secondary) -- Zimbabwe Computer-assisted instruction -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1576 , http://hdl.handle.net/10962/d1003458
- Description: As personal computers (PCs) and related ICTs become more and more omnipresent than ever before in institutions of education, teachers are faced with the challenge of having to teach in ICT rich environments. Some syllabuses increase this pressure by stipulating where ICT may be applied. While past research efforts have focused on presence of and/or effectiveness of ICTs on achieving various didactic goals, there is limited literature on the extent to which actual practice occurred naturally. It was the aim of this study to determine the extent to which Physics teachers and students used ICT in their usual teaching/learning ambience, referred to as natural settings in this study. Using activity theory as a theoretical lens, multiple case studies were chosen as a strategy using 10 schools, 15 Physics teachers, 20 A-level Physics students and 10 ICT teachers (computer specialists). Questionnaires, observations and informal and focus group interviews were used to elicit responses from students, teachers and computer specialists. It emerged from the case studies that despite the presence of apt ICT infrastructure in the schools and although the teachers had a positive attitude towards the use of ICT for teaching and learning of Physics, teachers were apathetic when it came to the actual use. Some of the reasons militating against use were lack of an ICT policy, school authority, and monopoly of computers enjoyed by computer studies teachers. However among students there were ‘early starters’ who used ICTs outside of school, a situation that tended to change the Physics learning environment. These findings led to a proposal for a post of Computer Specialist (CS) in the schools. The need for developing ICT policy at all levels namely national, Ministry of Education and the school was also proposed. Lastly staff development in the use ICT for Physics teachers was proposed as indispensable.
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Interaction between arbuscular mycorrhizal fungi and soil microbial populations in the rhizosphere
- Authors: Ike-Izundu, Nnenna Esther
- Date: 2008
- Subjects: Mycorrhizas , Mycorrhizal fungi , Vesicular-arbuscular mycorrhizas , Soil microbiology , Rhizosphere , Revegetation , Restoration ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3962 , http://hdl.handle.net/10962/d1004021 , Mycorrhizas , Mycorrhizal fungi , Vesicular-arbuscular mycorrhizas , Soil microbiology , Rhizosphere , Revegetation , Restoration ecology
- Description: This study examined the rehabilitation potential of AM fungi with organic and inorganic fertilisers under pot and field trial conditions as well as their interaction with rhizospheric organisms and specific functional groups. In addition, the study highlighted the effects of land-use management on AM fungal populations in soil and the mycorrhizal status of some selected plants from one of the study sites. The study focussed on two sites that differ in operational activities and these included a mined area that was to be rehabilitated and a commercial farming site. A pot trial was conducted using an overburdened soil resulting from kaolin clay mining. Pots were seeded with Cynodon dactylon and treated with either Organic Tea or NPK (3:1:5) fertiliser, with or without AM fungal inoculum. The compatibility of these fertilisers with AM fungi was assessed by plant growth and percentage root colonisation. Maximum shoot height and plant biomass were observed at the 28th week with NPK (3:1:5) fertiliser supporting mycorrhizal colonisation by 80%. The result indicated the potential of AM fungi to be used in rehabilitation with minimal phosphate fertiliser. Similarly, a field trial was set-up using 17 x 17 m[superscript 2] plots in the mining site that were treated with the same organic and inorganic fertilisers as well as with AM fungal inoculum in different combinations. The interaction between AM fungi and soil microbial population was determined using culture dependent and culture independent techniques. The culture dependent technique involved the use of soil dilution and plating on general purpose and selective media. The result showed that there was no change in the total culturable bacterial number in the untreated and AM fungal treated plots, while a change in species composition was observed in the functional groups. Different functional groups identified included nitrogen fixing bacteria, pseudomonads, actinomycetes, phosphate solubilisers and the fungal counterparts. Gram-positive bacteria were observed as the predominant phenotypic type, while nitrogen fixers and actinomycetes were the predominant functional groups. Species identified from each functional group were Pseudomonas fulva, Bacillus megaterium, Streptomyces and actinomycetales bacteria. Meanwhile, fungi such as Ampelomyces, Fusarium, Penicillium, Aspergillus, Cephalosporium and Exserohilium were identified morphologically and molecularly. Furthermore, the mining site had a significantly higher bacterial number than the farming site thereby indicating the effects of land-use management on culturable bacterial numbers. The culture independent technique was carried out by cloning of the bacterial 16S rDNA and sequencing. Identified clones were Bradyrhizobium, Propionibacterium and Sporichthya. A cladogram constructed with the nucleotides sequences of identified functional species, clones and closely related nucleotide sequences from the Genbank indicated that nucleotide sequences differed in terms of the method used. The activity and establishment of the introduced AM fungal population was determined by spore enumeration, infectivity assay, percentage root colonisation and assessment of glomalin concentrations. The results indicated that the two land use types affected AM fungal populations. However, the establishment of AM fungi in the farming site was more successful than in the mining site as indicated by the higher infectivity pontential. Selected host plants, which were collected around the mine area, were observed to be mainly colonised by AM fungi and these were identified as Pentzia incana, Elytropappus rhinocerotis, Euphorbia meloformis, Selago corymbosa, Albuca canadensis and Helichrysum rosum. These plant species were able to thrive under harsh environmental conditions, thereby indicating their potential use as rehabilitation host plants. Generally, the findings of this study has provided an insight into the interaction between arbuscular mycorrhizal fungi and other soil microorganisms in two fields with differing land use management practices.
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Interest rate risk management : a case study of GBS Mutual Bank
- Authors: Williamson, Gareth Alan
- Date: 2008
- Subjects: GBS Mutual Bank , Interest rates -- Case studies , Interest rate risk -- Case studies , Risk management -- Case studies , Financial risk -- Case studies , Banks and banking -- Case studies
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:986 , http://hdl.handle.net/10962/d1002720 , GBS Mutual Bank , Interest rates -- Case studies , Interest rate risk -- Case studies , Risk management -- Case studies , Financial risk -- Case studies , Banks and banking -- Case studies
- Description: Banks play a pivotal role in the economic growth and development of countries, primarily through the diversification of risk for both themselves and other economic agents. Interest rate risk is regarded as one of the most prominent financial risks faced by a bank. A large portion of private banks’ revenue stems from net interest income that is generated from the difference between various assets and liabilities that are held on the balance sheet. Fluctuations in the interest rate can alter a bank’s interest income and value, making interest rate risk management vital to its success. The asset and liability committee of a bank is the internal committee charged with the duty of managing the bank’s interest rate risk exposure through the use of various hedging strategies and instruments. This thesis uses a case study methodology to analyse GBS Mutual Bank interest rate risk management. Its specific business circumstances, balance sheet structure and the market conditions over a specified period are used to comment on the practicality of a variety of balance sheet positioning strategies and derivative hedging instruments. The thesis also provides recommendations for the bank’s asset and liability committee in terms of its functions and organisation. It is elucidated that the most practical balance sheet hedging strategies are a volume strategy and immunisation, while the most practical derivative hedging instruments are interest rate futures and interest rate collars. It is found that the bank has a well functioning asset and liability committee whose only encumbrance to its functionality is the inadequacy of the informational technology used to measure, control and manage its interest rate risk position. This thesis concludes by summarising the practicality of the various interest rate risk hedging alternatives available to the GBS Mutual Bank. Implementing a particular strategy or instrument depends, of course, on its asset and liability committee’s decision.
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International law before municipal courts: the role of International Court of Justice decisions in domestic court proceedings with specific reference to United States case examples
- Authors: Mangezi, Mutsa
- Date: 2008
- Subjects: International Court of Justice -- Cases Vienna Convention on Consular Relations (1963) International and municipal law -- United States -- Cases International law -- United States -- Cases Jurisdiction (International law) -- Cases
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3711 , http://hdl.handle.net/10962/d1007325
- Description: In the case of LaGrand (Germany v United States), the International Court of Justice held that the United States (US) had violated its international obligation to Germany under the Vienna Convention on Consular Relations when it executed two German nationals without first informing them of their consular rights. The case came before the court after the United States had disregarded a preliminary ruling passed by the IC], which directed the US not to execute the German nationals pending the outcome of the ICJ case. The decision raised the issue of the effect of ICJ decisions in domestic proceedings and the effectiveness of ICJ enforcement mechanisms. This thesis considers the possibility of a role for national courts as active enforcers of ICJ decisions. It is argued that whilst evidence shows that there is no legal obligation on courts to enforce ICJ decisions, there is certainly room in international law to facilitate this development. In support of this argument, the thesis demonstrates how basic presuppositions about international law have shifted over the last few decades. This shift has been both the impetus and the result of globalisation. The case of LaGrand alongside similar cases is used to show how national courts may play an increased role in the enforcement of ICJ decisions.
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Investigating aspects of corporate citizenship on private game farms: the case of Mtshelezi Game Reserve in Makana Municipality, Eastern Cape Province
- Authors: Nyama, Cynthia
- Date: 2008
- Subjects: Tourism -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Agricultural laborers -- South Africa -- Eastern Cape -- Social conditions , Agricultural laborers -- South Africa -- Eastern Cape -- Economic conditions , Social responsibility of business -- South Africa -- Eastern Cape , Ecotourism -- South Africa -- Eastern Cape -- Citizen participation , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:751 , http://hdl.handle.net/10962/d1003872 , Tourism -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Agricultural laborers -- South Africa -- Eastern Cape -- Social conditions , Agricultural laborers -- South Africa -- Eastern Cape -- Economic conditions , Social responsibility of business -- South Africa -- Eastern Cape , Ecotourism -- South Africa -- Eastern Cape -- Citizen participation , Rural development -- South Africa -- Eastern Cape
- Description: Research show that post 1996 period has experienced an unprecedented increase in game based operations. The corporate citizenship or corporate social responsibility of the game reserves is of much interest to this study with a focus on the rights of previous and current occupants of farms, workers’ well-being, job creation, quality of life and poverty alleviation within the game/tourism industry. The research was conducted as a qualitative case study and the tools employed for data gathering include: a review of the relevant literature, interviews (face-to-face), the administering of a questionnaire survey and document analysis from diversity of resources which include the Department of Labour, East Cape Agricultural Research Project, and through use of multiple data sources. The approach taken in this dissertation is to examine to what extent the private game reserves in the Makana Municipality can be labelled as “corporate citizens” and this was done by means of a case study of one private game reserve. The areas that are deemed to be most important in this regard are (i) employment history (ii) educational opportunities (iii) wages (iv) housing (v) land tenure. The study established that younger, better educated people are likely to secure better paying employment on PGR. The nature and conditions of sale of the farm to the PGR can impact on the employment secured by workers in the new dispensation. Workers are tied to these jobs because of the very long hours that prevent them from doing anything else to earn money. Some of the workers had opportunities to learn new skills but the question remains; which people are these and how long will growing differentials in earnings reproduce the poorly educated worker in the next generation. The study also high lightened the need for academics and researchers to come with a common set of corporate citizenship measures such as to measure corporate social impacts.
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Investigating learning interactions influencing farmers' choices of cultivated food plants
- Authors: Pesanayi, Victor Tichaona
- Date: 2008
- Subjects: Sustainable development -- Africa Poverty -- Africa Environmental education -- Zimbabwe Food supply -- Environmental aspects -- Zimbabwe Farmers -- Education -- Zimbabwe Agriculture -- Study and teaching -- Zimbabwe Plants, cultivated -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1587 , http://hdl.handle.net/10962/d1003469
- Description: The most critical hurdle on the path to sustainable development in Africa and the rest of the so-called Third World is poverty, commonly manifested as food security. A number of factors threaten food security in Zimbabwe, and these include climate change, an unstable socio-political environment and economic depression. The major debates and initiatives on sustainable development often fail to focus on the eradication of poverty in southern Africa. As a result, the trade liberalisation programmes signed by African countries in economic partnership agreements leave smallholder farmers vulnerable to the influx of hybrid seed and genetically modified organisms (GMOs), which threaten local agro-biodiversity. This case study has shown that farmers select seed to plant for food as a result of various learning interactions they engage in, which include inter-generational knowledge transfer, farmer to farmer extension and external training by extension organisations and NGOs. A communities of practice (COPs) (Wenger, 2007) framework was used to gain an understanding of the learning interactions among farmers and their stakeholders in Nyanga and Marange COPs of small grain farmers in Manicaland Province, Zimbabwe, who have been working with Environment Africa (A regional NGO). A critical realist causal analysis was conducted to unravel the various causal factors influencing choice. A number of underlying structures and causal mechanisms were found to influence learning interactions and choices in these communities of practice, and they include ambivalence, which influences the changing domain and practice. Climate change, drought and risk were found to affect farmer practice, while power relations affect the community, its practice, domain, sponsorship and the learning interactions in the COPs. The political economy was also found to have a profound effect on the domain and practice. A space was found for the influence of capacity and knowledge sharing in participatory frameworks of the communities, implying that extension quality can be enhanced to promote locally adapted and diverse seed varieties for food security improvement. The study shows that a deeper understanding of the mechanisms influencing the context of teaching and learning provides a more refined insight into the learning interactions and choices of farmers. This, coupled with the social processes descriptors provided by Wildemeersch (2007) has given me a more detailed understanding of the nature of learning interactions influencing farmer choices.
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Investigating the role of portfolios in developing reflective practice : a case study
- Authors: Mbango, Karolina Naango
- Date: 2008
- Subjects: Portfolios in education -- Namibia -- Case studies Student teachers -- Namibia -- Case studies Teachers -- Training of -- Namibia -- Case studies Teacher educators -- Namibia -- Case studies Reflective teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1595 , http://hdl.handle.net/10962/d1003477
- Description: The purpose of this study was to investigate the purpose and role portfolios are playing in developing reflective practice in student teachers and to assess the degree to which this role is being achieved in practice. This study was a interpretive small scale case study. The target groups were 3 student teachers in their final year of study, 3 teacher educators and the vice-rector of the college. Data were obtained through interviews and document analysis. The findings indicated that the students had no meaningful orientation to both the role of portfolio development and reflective skills. The sources of this were the lack of common understanding among teacher educators, lack of support for both teacher educators and student teachers and lack of time, lack of guidelines for construction and clear assessment rubric. The results of this study indicated that the teacher educators were in need of vigorous professional development and considerable implementation strategies are needed to develop the desired reflective skills.
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Isolation and characterization of antiplasmodial metabolites from South African marine alga
- Authors: Afolayan, Anthonia Folake
- Date: 2008
- Subjects: Malaria -- Africa Antimalarials -- Therapeutic use Malaria -- Prevention Malaria -- Drug therapy Marine algae -- Therapeutic use Natural products -- Therapeutic use Plasmodium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3739 , http://hdl.handle.net/10962/d1003063
- Description: Malaria is one of the three most deadly diseases in Africa. Although there are available treatments, their efficacy has been greatly reduced over the past two decades due to the development of resistance to currently available drugs. This has necessitated the search for new and effective antimalarial agents. This project approached the search for new antimalarial compounds in two ways: (i) by screening natural products isolated from marine algae against the Plasmodium parasite and (ii) by modification of selected isolated active compounds to target 1-deoxY-đ-xylulose 5-phosphate reductoisomerase (DXR), an enzyme found in the nonmevalonate isoprenoid biosynthetic pathway of Plasmodium Jalciparum. It was envisaged that such a compound would exhibit dual action on the Plasmodium parasite. Extracts obtained from 22 marine algae were prefractionated by solvent partitioning and were screened for anti plasmodial activity against the chloroquine sensitive (CQS) P. Jalciparum D 10 strain. Overall, 50% of the algae screened produced at least one crude fraction with activity against P. Jalciparum. Extracts of the algae Sargassum heterophyllum, Plocamium cornutum, Amphiroa ephedrea and Pterosiphonia cloiophylla gave the most promising results. Fractionation of S. heterophyllum afforded three tetraprenyltoluquinols (3.1, 3.2 and 3.5) and an all-trans-fucoxanthin (3.6). Three new compounds (4.5, 4.6 and 4.7) and two known halogenated monoterpenes (4.1 and 4.4) were isolated from P. cornutum. Each of the isolated compounds from both S. heterophyllum and P. cornutum showed antiplasmodial activity with IC₅₀ values ranging from 2.0 - 15.3 μM for S. heterophyllum and 13 - 230 μM for P. cornutum. Attempts to synthetically modify halogenated monoterpene 4.4 by dihydroxylation and phosphorylation in order to inhibit the DXR enzyme was unsuccessful. However, the hemiterpene analogue (5.42) of the halogenated monoterpenes was successfully phosphorylated and dihydroxylated to give compound 5.45 which showed promising activity against DXR. The result obtained indicated that the proposed phosphorylation and dihydroxylation of the halogenated monoterpene 4.4 would result in the synthesis of a potent DXR inhibitor and therefore a potential antimalarial agent with dual mode of action on the Plasmodium parasite.
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Isolation, purification and characterization of a 'factor' from Fusarium oxysporum responsible for platinum nanoparticle formation
- Authors: Govender, Yageshni
- Date: 2008
- Subjects: Nanoparticles , Platinum , Fusarium oxysporum , Fungi , Hydragenase
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3923 , http://hdl.handle.net/10962/d1003982 , Nanoparticles , Platinum , Fusarium oxysporum , Fungi , Hydragenase
- Description: Nanoparticles are microscopic particles in the nanometre range of between 1-100 nm. A wide variety of metal nanoparticles have been found to be produced by prokaryotic and eukaryotic organisms including several fungal species, when exposed to solutions containing metal salts. Previous studies have suggested that this bioreduction of metal particles may occur via an active reductase/hydrogenase enzyme process where H2 is the electron donor and positively charged platinum species act as the electron acceptors becoming reduced to a neutral metal nanoparticle. In view of this on going research, the current study investigated the “factors” in the fungus Fusarium oxysporum which were responsible for platinum nanoparticle formation. The fungus F.oxysporum was used in this study as it has been previously shown to produce a variety of nanoparticles including gold and silver. During exposure of the biomass to H2PtCl6 the initial response to the platinum salts was metal internalisation and subsequent reduction of H2PtCI6 to produce platinum nanoparticles. The observed localization and distribution of platinum precipitates provided some evidence for a hydrogenase mediated bioreduction of platinum salts to produce nanoparticles. Factors secreted by the fungus into the extracellular fluids, were shown to be responsible for platinum nanoparticle formation. From the identification, purification and characterisation studies it was concluded that a hydrogenase and other “factors” were responsible for platinum nanoparticle formation in F.oxysporum. Purification of the hydrogenase by freeze-drying and Sephacryl S200 size exclusion- ion exchange chromatography revealed the enzyme to be a dimer with a 29.4 and 44.5 kDa when analysed by a 10 % SDS-PAGE. Characterisation of the enzyme revealed optimal activity at a pH of 7.5 and temperature of 38 °C while it exhibited a poor thermal stability with a half life of 36 minutes. The kinetic parameters Vmax and Km were 3.16 U ml-1 and 3.64 mM respectively. The purified hydrogenase was used in subsequent experiments for the reduction of platinum salts, H2PtCl6 and PtCl2. the results indicated an over 90 % reduction of the platinum salts and TEM micrographs indicated the production of platinum nanoparticles under the various experimental conditions.
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Journalists' appropriation of ICTs in news-gathering and processing: a case study of Grocott's Mail
- Authors: Dugo, Habtamu Tesfaye
- Date: 2008
- Subjects: Grocott's Mail (Grahamstown, South Africa) Journalism -- South Africa -- Grahamstown Journalists -- South Africa -- Grahamstown Electronic news gathering -- South Africa -- Grahamstown Journalism -- Data processing -- South Africa -- Grahamstown Information technology -- South Africa -- Grahamstown Reporters and reporting -- South Africa -- Grahamstown Communication and technology -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3427 , http://hdl.handle.net/10962/d1002881
- Description: This study set out to investigate Grocott’s Mail journalists’ appropriation of information and communication technologies in news-gathering and processing using the social shaping of technology as a theoretical lens. It mainly focuses on digital ICTs that journalists use in news-gathering and processing including the Internet, electronic mail, and mobile telephony. Grocott’s Mail is a small-scale newspaper based in Grahamstown, South Africa. Using qualitative research method and the case study as its sub-method, the research reveals that Grocott’s Mail journalists’ appropriation of ICTs involves various opportunities and challenges in news-gathering and processing. In terms of the state of the existing technological infrastructure, the study reveals that since it embraced the digital ICTs in 2003, Grocott’s Mail boasts an adequate ICT infrastructure for a small-scale African newspaper with 30 PCs and one laptop, and professional software for 28 permanent employees. On the other hand, the research reveals serious constraints with the existing ICTs: a huge need for staff training and capacity building to fully utilise the ICTs, and the need to look for ways of raising funds to either upgrade or replace the existing ICTs. Grocott’s Mail journalists use the Internet to do background research on news stories, to verify the accuracy of information, and to check competition across other media. These are the merits of the Internet in news-gathering and processing. On the other hand, there are specific unintended consequences of the Internet such as wasting the company’s working time, and its use leading to lazy/press release journalism. Informants unanimously indicate that the main problems of the Internet are heavy dependence on other online news-sources and wasting time on online entertainment. In terms of using email in news-gathering, the research finds email technology as having advantages such as being a tool of flexibility and speed, a tool for email interviews, and as a technology that promotes participatory journalism. On the other hand, challenges related to email include its limitations because of what interviewees view as its supplementary and small-scale use because of its low contextual richness as opposed to face to face interviews. In terms of cellular telephony, the study finds that regardless of the ubiquity of cell phones and cell phone networks, they have not yet been deployed in news-gathering and processing due to various constraints. These are cell phones not being a big factor in reporting, lack of a proper funding and refunding scheme, prevalence of negative attitudes towards cell phones, and lack of a business model. Thus, cellular phones seem to have little or no relevance in news-gathering and processing at Grocott’s Mail presently.
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Larval fish dynamics in the shallow nearshore of Eastern Algoa Bay with particular emphasis on the effects of currents and swimming abilities on dispersal
- Authors: Pattrick, Paula
- Date: 2008
- Subjects: Fishes -- Larvae -- Eastern Cape -- Algoa Bay , Marine parks and reserves -- Eastern Cape -- Algoa Bay , Fishes -- Larvae -- Ecology -- Eastern Cape -- Algoa Bay , Fishes -- Larvae -- Dispersal -- Eastern Cape -- Algoa Bay , Fishes -- Development -- Eastern Cape -- Algoa Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5294 , http://hdl.handle.net/10962/d1005139 , Fishes -- Larvae -- Eastern Cape -- Algoa Bay , Marine parks and reserves -- Eastern Cape -- Algoa Bay , Fishes -- Larvae -- Ecology -- Eastern Cape -- Algoa Bay , Fishes -- Larvae -- Dispersal -- Eastern Cape -- Algoa Bay , Fishes -- Development -- Eastern Cape -- Algoa Bay
- Description: The larval fish assemblage in the shallow, nearshore region of a proposed marine protected area (MPA) in eastern Algoa Bay, temperate South Africa was investigated. Current velocities and direction and the swimming abilities of late-stage larvae were further assessed to determine potential larval movement to and from the MPA. In total, 6045 larval fishes were collected along two depth contours (~5m and ~15m) in the shallow nearshore of eastern Algoa Bay using stepped-oblique bongo net tows, twice per season for two years (March 2005 – January 2007). These larvae represented 32 families and 78 species. The Gobiidae, Cynoglossidae, Clupeidae, Engraulidae and Sparidae were the dominant fish families. Catches varied significantly between seasons peaking in spring with a mean of 64 larvae/100m3. Preflexion stage larvae dominated catches (75%). All developmental stages of Diplodus capensis, Engraulis capensis, Heteromycteris capensis, Sardinops sagax and Pomadasys species were found in the study area. It appears that these species use the shallow nearshore as a nursery area. Analysis of 12 months (May 2006 – May 2007) data from a bottom-moored Acoustic Doppler Current Profiler within the study area showed that offshore south eastward (39%) and onshore north westward currents (33%) dominated. The south westward current (15%) and north eastward current (12%) occurred less frequently. Current velocity decreased with depth in the nearshore, with a mean velocity of ~29 cms⁻¹ recorded at a depth of 4 m and a mean velocity of ~11 cms⁻¹ recorded at a depth of 14 m. Understanding the dispersal and movement of marine fish larvae in coastal habitats requires knowledge of active swimming abilities. The critical speed and endurance swimming of late stage larvae of two common inshore species occurring in the study area, Diplodus capensis and Sarpa salpa (Family Sparidae), were measured in a laboratory swimming chamber. The mean U-crit value for D. capensis (18.6 cms⁻¹) was similar to that of S. salpa (18.0 cms⁻¹), whereas mean endurance (km swum) was greater in S. salpa (8.4 km) than D. capensis (5.9 km). These swimming abilities exceed the average current velocities observed in the shallow nearshore providing larvae with the ability to greatly alter their passive dispersal trajectories and ultimately influence their distribution in the nearshore.
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Lattice-valued uniform convergence spaces the case of enriched lattices
- Authors: Craig, Andrew Philip Knott
- Date: 2008
- Subjects: Lattice theory , Uniform spaces , Convergence
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5411 , http://hdl.handle.net/10962/d1005225 , Lattice theory , Uniform spaces , Convergence
- Description: Using a pseudo-bisymmetric enriched cl-premonoid as the underlying lattice, we examine different categories of lattice-valued spaces. Lattice-valued topological spaces, uniform spaces and limit spaces are described, and we produce a new definition of stratified lattice-valued uniform convergence spaces in this generalised lattice context. We show that the category of stratified L-uniform convergence spaces is topological, and that the forgetful functor preserves initial constructions for the underlying stratified L-limit space. For the case of L a complete Heyting algebra, it is shown that the category of stratified L-uniform convergence spaces is cartesian closed.
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Life history, population dynamics and conservation status of Oldenburgia grandis (Asteraceae), an endemic of the Eastern Cape of South Africa
- Authors: Swart, Carin
- Date: 2008
- Subjects: Compositae , Fynbos ecology -- South Africa -- Eastern Cape , Endemic plants -- South Africa -- Eastern Cape , Rare plants -- South Africa -- Eastern Cape , Plant populations -- South Africa -- Eastern Cape , Vegetation dynamics -- South Africa -- Eastern Cape , Plant conservation -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4230 , http://hdl.handle.net/10962/d1003799 , Compositae , Fynbos ecology -- South Africa -- Eastern Cape , Endemic plants -- South Africa -- Eastern Cape , Rare plants -- South Africa -- Eastern Cape , Plant populations -- South Africa -- Eastern Cape , Vegetation dynamics -- South Africa -- Eastern Cape , Plant conservation -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape
- Description: Oldenburgia grandis is a rare, long-lived woody paleoendemic of the Fynbos Biome of South Africa. Confined to quartzite outcrops, it has a small geographic range and narrow habitat specificity. O. grandis responds to its fire-prone environment by resprouting. Elasticity analysis of O. grandis reveals that growth and fecundity were traded off for persistence of adult, mature and sapling stages. Morphological adaptations such as a corky fire-resistant bark and the ability to resprout after fire are traits that O. grandis have evolved to persist in a frequently disturbed environment. Population growth rate for sites undisturbed by fire for a number of years (l = 1.01) and sites at various stages of recovery after fire (l = 1.00) were very similar. The highest variation in transition probabilities for all sites was seen in the persistence of the seedling stage and growth from seedling to sapling. Observed population structure and stable stage distribution determined by the matrix model show that sites recently undisturbed by fire had high abundances of the adult and sapling stages. A peak in sapling stages was seen for the stable stage distribution where similar peak in sapling numbers were seen for population structures of sites at various stages of recoveryafter fire. Favourable environmental conditions for the persistence of O. grandis populations include no fire with transition probabilities between the observed minimum and maximum and fire frequency at a 10 year interval where seedling protection from the fire is high and adult and mature mortalities during the fire are low. Stochastic environmental events that could put populations (particularly small populations) at an increased risk of extinction include high to moderate fire intensities where seedling protection from the fire is low and adult and mature mortalities are high as a result of the fire.
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Life in the suburbs after "Grootboom": the role of local government in realising housing rights in the Eastern Cape
- Authors: Kruuse, Helen Julia
- Date: 2008
- Subjects: Right to housing , Human rights -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Housing -- Law and legislation -- South Africa -- Eastern Cape , Housing policy -- South Africa -- Eastern Cape , Low income housing -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3678 , http://hdl.handle.net/10962/d1003193 , Right to housing , Human rights -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Housing -- Law and legislation -- South Africa -- Eastern Cape , Housing policy -- South Africa -- Eastern Cape , Low income housing -- South Africa -- Eastern Cape
- Description: When the Government of National Unity took office in 1994, it inherited a country with severe inequalities in resource distribution and land ownership. In particular, it inherited a housing crisis which was, to a large extent, caused by apartheid legislation and policies. This research focuses on the housing crisis post-1994 by considering the impact and effect of the constitutional right to have access to adequate housing, especially for those living in intolerable conditions. It does so by utilising a social-scientific approach to the law. This approach acknowledges that the housing right must exist alongside other social phenomena and as a part of everyday life in South Africa. Accordingly, the implementation of the housing right by three local municipalities in the Eastern Cape is examined. Following an initial overview of the history of housing and local government in South Africa, the study focuses on the current legislative framework for housing and theinterpretation of the housing right (and other socio-economic rights) in certain court decisions. These decisions are discussed, not only because of the impact they have had on communities living in intolerable situations, but, as importantly, because they have developed standards against which policy and planning should be measured. These standards are used in the study to evaluate housing provision in three municipalities. The evaluation (by means of interviews and assessment of planning documentation) demonstrates that the recognition of the housing right in the Constitution and by the courts does not necessarily translate into effective recognition and implementation by the state. The research shows that the failure to plan proactively, lack of co-operative governance and inadequate controls over financial and human resources thwart the realisation of the housing right by local government. It is recommended that, in order to make the housing right a reality, research into the housing right (and indeed other socio-economic rights) should scrutinise the management of financial and human resources of the state in the context of the policy, planning and implementation environment. Where research is able to show evidence of unspent budgets, insufficient planning and mismanagement of resources, courts would be able to focus on the implementation aspect of the housing right, and ensure that it may yet have a meaningful impact on the lives of millions of some of the most vulnerable people in society.
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Locating the border the development of the framing device in Western art
- Authors: Leathem, Kevin Wolhuter
- Date: 2008
- Subjects: Picture frames and framing Mural painting and decoration Art museums -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2408 , http://hdl.handle.net/10962/d1002204
- Description: A frame can be understood to act as something both complementary and even intrinsic to the work it houses. But the frame also acts as more than just a physical object. It serves as a guiding principle, perhaps even a controlling device, in the sense that it provides a context for the work as well as informing the way in which a work is read. Acting with the image it surrounds, it links the artwork to the surrounding space as well as the viewer. In this study, I explore these various functions and effects by providing an overview of framing devices that have been used by artists in the West as well as referring to guiding principles that some museums in South Africa have used when making choices about the ways in which they frame works in their collections. This examination provides a context for my paintings. Based on photographs of the walls of various small galleries in the Eastern Cape, my works take as their subject the notion of the ‘frame’ as both a physical object and the marker of a historically contextualized viewpoint.
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Melanie Klein: a psychobiographical study
- Authors: Espinosa, Marianna J
- Date: 2008
- Subjects: Klein, Melanie Psychology -- Biographical methods Psychoanalysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2971 , http://hdl.handle.net/10962/d1002480
- Description: The objective of psychobiography is a better understanding of individuals, and psychobiographical case studies add meaning and value to research (Runyan, 1988a). Melanie Klein was chosen for this study through a purposive sampling method due to her contributions to the discipline of psychology, which placed her in a distinguished position regarding twentieth century psychoanalysis. Furthermore, no other psychobiography has been written on Klein. The primary aim of this study was to present the reader with a basic description of her life, and a secondary aim was to accomplish an in-depth description of Klein within her social and historical context. Due to these aims and the nature of psychobiography, it may be said that this is a qualitative study based on a single case method, described as explorative and descriptive. Data was analysed according to Huberman and Miles’ (1994) approach which consists of data reduction, display and verification. This study was guided by Levinson’s (1996) theory of Adult Development in Women. The theory allowed for an in-depth description of Klein’s experiences and social and historical contexts by merely illuminating her life. Finally, it may be said that this study contributed to the limited amount of psychobiographical research in South Africa.
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Microfinance sustainability versus development objectives: an assessment of the South African environment
- Authors: Hoskinson, Brenda
- Date: 2008
- Subjects: Microfinance -- South Africa South Africa -- Economic conditions -- 1991- Poor -- Finance, Personal Microfinance -- South Africa Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2782 , http://hdl.handle.net/10962/d1002992
- Description: In a world where almost half of the population lives in poverty, the alleviation of poverty is a serious developmental challenge for many states. Microfinance has grown in popularity as a means for achieving poverty reduction all over the world. Due to the success of microfinance institutions, such as the Grameen Bank, in achieving self-sufficiency and improving the lives of its clients, the expectations for similar institutions are high. MFIs attempt to find a balance between business and development goals. It is not necessarily a contradiction to be a business seeking profit as well as being an institution committed to development. However, the values coupled with these two objectives are sometimes conflicting. Thus it is important to see how equilibrium can be achieved and to note what sacrifices must be made in order to reach a balance. This thesis will focus on examining and assessing the challenges faced by South African MFIs in balancing development goals while at the same time having to be self-sufficient. The Small Enterprise Foundation will be used as a case study to consider the particular experiences of a South African MFI. The evaluation of the unique challenges that the South African landscape presents will provide a context in which to understand microfinance operations and a clearer understanding of the particular problems and challenges faced by the South African micro-finance industry in balancing the achievement of development goals against the imperative to be self sustainable in providing services to the poor. Through that understanding the common conception of what makes a “successful” MFI will also be challenged.
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