Bioaccumulation and ecotoxicology of b-methylamino-l-alanine (BMAA) in model crop plants
- Authors: Niyonzima, Francois Niyongabo
- Date: 2010
- Subjects: Cyanobacteria , Environmental toxicology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10312 , http://hdl.handle.net/10948/1475 , Cyanobacteria , Environmental toxicology
- Description: Cyanobacteria are known to produce a variety of toxic compounds. β-N-methylamino-L-alanine (BMAA) is one of the neurotoxins produced by most cyanobacteria. BMAA has been implicated in amyotrophic lateral sclerosis / Parkinsonism dementia complex (ALS / PDC) and was suggested to contribute to this pathology after biomagnification and slow release of BMAA from a protein associated form. The uptake and accumulation of BMAA by the aquatic macrophyte Ceratophyllum demersum has recently been shown, but the consumption of aquatic macrophytes by humans is not typical. The uptake by, and accumulation in, crop plants (Nasturtium officinale and Daucus carota) was therefore investigated so as to establish the existence of any risk to humans from the consumption of plants irrigated with water from dams with high cyanobacterial biomass and therefore high BMAA levels. After the exposure to the BMAA through the growth medium, BMAA had no effect on growth and development of N. officinale and D. carota. The uptake and bioaccumulation of BMAA was observed in N. officinale and D. carota, and was found to be concentration-dependent. Both free and bound cellular BMAA was detected following BMAA exposure through the growth medium. The photosynthetic apparatus of N. officinale was not significantly damaged. The uptake and accumulation of BMAA in edible terrestrial plants may constitute another route of human exposure to BMAA; it may now be prudent to avoid spray irrigation of edible plants with waters from dams with high cyanobacterial biomass and therefore high BMAA levels. After uptake by plants, the cyanotoxins may induce oxidative stress. A recent study showed that BMAA has a significant inhibitory effect on the oxidative stress enzymes in C. demersum. Therefore, the toxicological effects on selected plants were investigated by a range of biochemical enzyme assays in order to establish the plant stress response to exogenous BMAA. The inhibition of antioxidant enzymes upon exposure of N. officinale to BMAA through the growth medium was observed. The inhibition of antioxidant defence enzymes by BMAA correlated with the BMAA bioaccumulation in N. officinale. Further investigations are needed to analyze the uptake, accumulation, and ecotoxicology of BMAA in other crop plants, and to examine the fate of BMAA in these plants particularly its distribution and metabolism.
- Full Text:
- Date Issued: 2010
Bioethanol production from waste paper through fungal biotechnology
- Authors: Voigt, Paul George
- Date: 2010
- Subjects: Biomass energy , Cellulose -- Biodegradation , Waste paper -- Recycling , Biomass chemicals -- Economic aspects , Renewable energy sources , Fungi -- Biotechnology , Enzymes -- Biotechnology
- Language: English
- Type: Thesis , MSc , Masters
- Identifier: vital:3861 , http://hdl.handle.net/10962/d1013447
- Description: Bioethanol is likely to be a large contributor to the fuel sector of industry in the near future. Current research trends are geared towards utilizing food crops as substrate for bioethanol fermentation; however, this is the source of much controversy. Utilizing food crops for fuel purposes is anticipated to cause massive food shortages worldwide. Cellulose is the most abundant renewable resource on earth and is subject to a wide array of scientific study in order to utilize the glucose contained within it. Waste paper has a high degree of cellulose associated with it, which makes it an ideal target for cellulose biotechnology with the ultimate end goal of bioethanol production. This study focussed on producing the necessary enzymes to hydrolyse the cellulose found in waste paper and using the sugars produced to produce ethanol. The effects of various printing inks had on the production of sugars and the total envirorunental impact of the effluents produced during the production line were also examined. It was found that the fungus Trichoderma longibrachiatum DSM 769 grown in Mandel's medium with waste newspaper as the sole carbon source at 28 °C for 6 days produced extracellular cellulase enzymes with an activity of 0.203 ± 0.009 FPU.ml⁻¹, significantly higher activity as compared to other paper sources. This extracellular cellulase was used to hydrolyse waste newspaper and office paper, with office paper yielding the highest degree of sugar production with an end concentration of 5.80 ± 0.19 g/1 at 40 °C. Analysis by HPLC showed that although glucose was the major product at 4.35 ± 0.12 g/1, cellobiose was also produced in appreciable amounts (1.97 ± 0.71 g/1). The sugar solution was used as a substrate for Saccharomyces cerevisiae DSM 1333 and ethanol was produced at a level of 1.79 ± 0.26 g/1, the presence of which was confirmed by a 600 MHz NMR spectrum. It was found that cellobiose was not fermented by this strain of S. cerevisiae. Certain components of inks (the PAHs phenanthrene and naphthalene) were found to have a slight inhibitory effect (approximately 15% decrease) on the cellulase enzymes at very high concentrations (approximately 600 μg/1 in aqueous medium), while anthracene had no effect. Whole newsprint ink was shown not to sorb glucose. The environmental analysis of the effluents produced showed that in order for the effluents to be discharged into an aqueous ecosystem they would have to be diluted up to 200 times. They were also shown to have the potential to cause severe machinery damage if reused without proper treatment.
- Full Text:
- Date Issued: 2010
Broadening the tax base: a case for the informal real estate sector in Zambia
- Authors: Siame, Chilengwe George
- Date: 2010
- Subjects: Real property and taxation -- Zambia Tax administration and procedure -- Zambia Rental housing -- Taxation -- Law and legislation -- Zambia Informal sector (Economics) -- Taxation -- Law and legislation -- Zambia
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:732 , http://hdl.handle.net/10962/d1003852
- Description: The main objective of the study was to analyze the potential tax collection from the informal rental housing market in Zambia, using household level rental housing data collected for the Lusaka Urban District by the Central Statistical Office (CSO) as a basis for computation and extrapolation to the national level. This data was used to analyze household monthly expenditure on housing (rent), the total number of households in rented accommodation, and the tax regime applicable on rental income, to estimate the potential tax revenue that could be realized from this emerging sector. The estimates indicate that about K9.7 billion revenue could be collected on income from rental housing in Lusaka Urban District alone and a total of K83 billion nationally per annum. This represents about 0.4 percent of the country’s GDP in 2007. Compliance needs to be improved and legislation revised to ensure that the landlords are compelled to remit tax to the Zambia Revenue Authority. The current legislation makes enforcement and compliance difficult as it places the statutory tax burden on tenants, who are very mobile. It is, therefore, recommended that the landlord is made responsible for the payment of taxes due on rental income and that any compliance requirements be enforced against the real estate/property that is generating the income. This study also examines the performance of the presumptive taxation regime in Zambia The study uses data from the Zambia Revenue Authority on revenue collection from presumptive taxes which were introduced to capture income from the informal sectors. The presumptive taxes already introduced in Zambia include: base tax, advance income tax and turnover tax for minibuses and taxi operators. To analyze the performance of the presumptive tax regime, the study utilizes data on imports made by those not registered for taxes, to estimate how much revenue could be generated by imposing a 3 percent turnover tax on the value of their imports at importation. The analysis shows that the Zambia Revenue Authority increased revenue collection from K5.3 billion in 2004 to K33.5 billion in 2007. This improvement in revenue collection is far below the potential, however, which is estimated at over K501 billion on imports of unregistered traders alone. To collect this revenue and expand the tax base, the tax authority needs to improve the administration of advance income tax on unregistered importers, and raise the advance income tax rate to a level where the importer is indifferent between paying the advance tax at the border and paying turnover tax inland.
- Full Text:
- Date Issued: 2010
Brood cycles in queenless colonies of Apis mellifera capensis
- Authors: Crous, Kendall Lauren
- Date: 2010
- Subjects: Cape honeybee , Bee culture -- Queen rearing , Bees -- Breeding
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5652 , http://hdl.handle.net/10962/d1005335 , Cape honeybee , Bee culture -- Queen rearing , Bees -- Breeding
- Description: In a honeybee colony, the loss of a queen is considered to be a serious occurrence and, if a new queen is not produced, ultimately doomed. However, in colonies of Apis mellifera capensis (Cape honeybees), numerous pathways are available for a colony which unexpectedly losses a queen. At the onset of this experiment, four colonies of A. m. capensis were dequeened. Following this photographs of all brood frames in each colony were taken and the contents of the cells analysed. Cells were chosen at random but once selected were repeatedly analysed for the duration of the experiment. The contents of a total of 44 888 individual cells were analysed. Any queen cells constructed during the sampling period were removed, maintaining a queenless state. In each colony, as predicted, the removal of the queen evoked a variety of responses in an attempt to rectify the sudden loss. However, ultimately three of the four colonies absconded, leaving little by way of stores. Three of the four colonies initially attempted to rear a new queen while one colony was immediately invaded by a presumed foreign queen and hence any attempt at queen cell construction ceased. An increased number of queen cells in the swarm position were recorded in all colonies. The invasion of a colony by a foreign queen was considered to be a new pathway available for queenless colonies of A.m capensis. Worker policing and suspected brood cannibalism was prevalent in all sampled colonies yet in addition, the transfer of eggs and larvae from cell to cell was also observed which may have increased the suspected cases of policing and cannibalism. It was unclear whether an egg or larva had been consumed or simply moved to another cell on the brood frame. All colonies contained eggs from laying workers to varying degrees, based on the length of each individual sampling period which varied between colonies due to differences in absconding dates. A steady breakdown in the effectiveness of the division of labour amongst the worker bees was observed in each of the colonies highlighting the vital role of a queen. This breakdown was clearly seen in the reduction in general housekeeping within a colony. An increase in stores indicated a possible increase in the number of forager bees, thereby reducing the number of worker bees available for other duties. Pathways available to broodright colonies and strategies used following sudden queen loss are discussed.
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- Date Issued: 2010
Building a semantic web-based e-health component for a multipurpose communication centre
- Authors: Hlungulu, Bulumko
- Date: 2010
- Subjects: Rural development -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Internet in medicine -- South Africa -- Eastern Cape , Telecommunication in medicine -- South Africa -- Eastern Cape , Health -- Computer network resources
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11380 , http://hdl.handle.net/10353/374 , Rural development -- South Africa -- Eastern Cape , Information technology -- South Africa -- Eastern Cape , Internet in medicine -- South Africa -- Eastern Cape , Telecommunication in medicine -- South Africa -- Eastern Cape , Health -- Computer network resources
- Description: Rural communities have limited access to health information which is made available on the internet. This is due to poor infrastructure (i.e., lack of clinics or Internet access) and that gives them problems in accessing information within the domain of health. The availability of Information and Communication Technologies (ICTs) in a rural community can provide the community with a number of beneficial solutions to their problems as they maximize the potential of knowledge sharing and delivery. This research seeks to make use of ICTs deployed in the community of Dwesa, in order to contribute to improving the health standards of the community. It seeks to accomplish this by carrying out an investigation and literature review with the aim of understanding health knowledge sharing dynamics in the context of marginalized communities. The knowledge acquired will then be used in the development and implementation of a semantic web-based e-Health portal as part of the Siyakhula Living Lab (SLL) project. This portal will share and deliver western medical knowledge, traditional knowledge and indigenous knowledge. This research seeks to make use of a combination of Free and/or Open Sources Software in developing the portal to make it affordable to the community.
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- Date Issued: 2010
Business journalism ethics in Africa: a comparative study of newsrooms in South Africa, Kenya and Zimbabwe
- Authors: Mare, Admire
- Date: 2010
- Subjects: Journalism, Commercial Journalistic ethics Journalism, Commercial -- South Africa Journalism, Commercial -- Kenya Journalism, Commercial -- Zimbabwe Business Day (South Africa) Business Daily (Kenya) Financial Gazette (Zimbabwe)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3458 , http://hdl.handle.net/10962/d1002912
- Description: This study provides an insight into the state of business journalism ethics in Africa, firstly through an examination of newsroom ethical policies and secondly through an exploration of the way in which African business journalists negotiate ethical decision-making in their day-to-day news processing practices. Thirdly, it examines how the three African media organisations have responded in their newsroom policies and practices to the debates on the Africanisation of journalism ethics. In order to collect data, the researcher employed document analysis, semi-structured questionnaires and in-depth interviews. Three financial newspapers namely: Business Day in South Africa, Business Daily in Kenya and Financial Gazette in Zimbabwe were purposively chosen. In these African countries, business journalism has been steadily growing since the late 1960s, fuelled by the presence of robust stock exchanges, making the issue of business journalism ethics of central importance. Grounded in the sociology of news production paradigm, Bourdieu’s journalistic field theory and debates on Africanisation of journalism ethics, this study identifies three major issues. First, the research found that while all three newspapers had clear ethical guidelines in place, and editors and journalists recognised the importance of ethical behaviour, ethical practice did not always follow. A disconnect exists between words (codes of ethics) and actions (practice) especially in Kenya and Zimbabwe, where business journalists are more susceptible to economic and political pressures. The argument is ethical considerations notwithstanding, people need to survive. This is largely due to the precarious economic basis of news organisations, lack of effective monitoring, and a pervasive culture of unethical behaviour at some sites. Second, the study also shows that institutional factors such as advertising, powerful news sources and interference from senior management make ethical business journalism difficult to practice. Third, Africanisation remains an academic issue with little movement towards that direction in most newsrooms studied. The findings of this study demonstrate that business editors in African newsrooms are confused on what ‘Africanisation’ entails especially given their shared view that journalism practices are universal. It recommends that business journalism codes of ethics informed by African values are long overdue. In terms of enforcement and monitoring of codes, it is important to use compliance officers or ombudsperson and periodically run in-house refresher courses on ethics and professionalism. It is imperative that the financial press improve the working conditions of its employees in order to lessen incidences of corruption which are threatening the credibility of media content and media organisation themselves.
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- Date Issued: 2010
C3TO : a scalable architecture for mobile chat based tutoring
- Authors: Butgereit, Laura Lee
- Date: 2010
- Subjects: Intelligent tutoring systems , Instructional systems -- Design
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9746 , http://hdl.handle.net/10948/1511 , Intelligent tutoring systems , Instructional systems -- Design
- Description: C³TO (Chatter Call Centre/Tutoring Online) is a scalable architecture to support mobile online tutoring using chat protocols over cell phones. It is the scalability of this architecture which is the primary focus of this dissertation. Much has been written lamenting the state of mathematics education in South Africa. It is not a pretty story. In order to help solve this mathematical crisis, the “Dr Math” research project was started in January, 2007. “Dr Math” strove to assist school pupils with their mathematics homework by providing access to tutors from a nearby university to help them. The school pupils used MXit on their cell phones and the tutors used normal computer workstations. The original “Dr Math” research project expected no more than twenty to thirty school pupils to participate. Unexpectedly thousands of school pupils started asking “Dr Math” to assist them with their mathematics homework. The original software could not scale. The original software could not cater for the thousands of pupils needing help. The scalability problems which existed in the original “Dr Math” project included: hardware scalability issues, software scalability problems, lack of physical office space for tutors, and tutor time being wasted by trivial questions. C³TO tackled these scalability concerns using an innovative three level approach by implementing a technological feature level, a tactical feature level, and a strategic feature level in the C³TO architecture. The technological level included specific components, utilities, and platforms which promoted scalability. The technological level provided the basic building blocks with which to construct a scalable architecture. The tactical level arranged the basic building blocks of the technological level into a scalable architecture. The tactical level provided short term solutions to scalability concerns by providing easy configurability and decision making. The strategic level attempted to answer the pupils questions before they actually arrived at the tutor thereby reducing the load on the human tutors. C³TO was extensively tested and evaluated. C³TO supported thousands of school pupils with their mathematics homework over a period of ten months. C³TO was used to support a small conference. C³TO was used to encourage people to volunteer their time in participation of Mandela Day. C³TO was used to support “Winter School” during the winter school holiday. In all these cases, C³TO proved itself to be scalable.
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- Date Issued: 2010
Challenges facing health professionals in OR Tambo health district municipalities
- Authors: Mduba, Nomasomi Cynthia
- Date: 2010
- Subjects: Medical personnel -- South Africa -- Eastern Cape , Municipal services -- South Africa -- Eastern Cape , Performance -- Evaluation , Health facilities -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11627 , http://hdl.handle.net/10353/278 , Medical personnel -- South Africa -- Eastern Cape , Municipal services -- South Africa -- Eastern Cape , Performance -- Evaluation , Health facilities -- South Africa -- Eastern Cape
- Description: My motivation to conduct this study was triggered by my exposure to the challenges which form the basis of this study. Being employed in the same environment as the respondents, it became natural for me to resolve to investigate the challenges facing these Health Professionals with the purpose of not only establishing what the challenges are but simultaneously propose remedial solutions to mitigate their impact. This study is both qualitative as well as quantitative to make sure that both the numerical as well as the social issues which impact these professionals‘ work were captured in the study. The assumptions from which the study moved were largely confirmed by the respondents. The recommendations which the researcher proposes to mitigate the challenges are informed by her own experience as well as the responses which were elicited from the respondents. While the study does contribute in a way to the body of knowledge, it is cautioned in the concluding chapter that recommendations made must be considered with this caution in mind as the study was limited to a specific environment – the OR Tambo District Health Municipality.
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- Date Issued: 2010
Citrus, labour and gender in the Eastern Cape: the case of the Kat River area
- Authors: Mzitshi, Zoleka Alice Florence
- Date: 2010
- Subjects: Citrus -- South Africa -- Eastern Cape , Citrus , Working class women -- South Africa -- Eastern Cape , Sex role -- South Africa -- Eastern Cape , Citrus fruit industry -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Geography)
- Identifier: vital:11511 , http://hdl.handle.net/10353/379 , Citrus -- South Africa -- Eastern Cape , Citrus , Working class women -- South Africa -- Eastern Cape , Sex role -- South Africa -- Eastern Cape , Citrus fruit industry -- South Africa -- Eastern Cape
- Description: Agriculture plays a significant role in South Africa’s export earning and in providing employment opportunities. Amongst the major agricultural crops is citrus. Within the context of postmodern and feminist geographies and utilizing the intensive research design, this thesis discusses citrus production with a focus on growers and black women workers in the Kat River Valley area in Fort Beaufort, Eastern Cape. The thesis also explores the challenges and implications of restructuring within agriculture for growers, cooperatives and labour within the citrus industry. It is argued that whilst legislation related to labour and tenure within agriculture has changed since the mid-1990s, power relations in the citrus industry have remained firmly entrenched. Consequently, the flexible labour strategies that the citrus farmers adopted have had serious consequences for women worker
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- Date Issued: 2010
Collaborative monitoring in ecosystem management in South Africa's communal lands
- Authors: Bolus, Cosman
- Date: 2010
- Subjects: Conservation of natural resources -- South Africa , Natural resources -- South Africa -- Management , Community development -- South Africa -- Citizen participation , Conservation of natural resources -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4743 , http://hdl.handle.net/10962/d1006948 , Conservation of natural resources -- South Africa , Natural resources -- South Africa -- Management , Community development -- South Africa -- Citizen participation , Conservation of natural resources -- Social aspects -- South Africa
- Description: Internationally there is an increasing focus on involving local communities in natural resource management and monitoring. Monitoring methods which are professionally driven appear to be inadequate to deal with the monitoring of natural resource use and biodiversity conservation, globally. This is especially evident in areas such as South African rural communal land. Two community based natural resource management (CBNRM) programmes in areas which are communally governed in the Eastern Cape, South Africa, namely Nqabara and Machubeni, were used as part of this research study. This thesis identified and tested potentially simple and cost effective monitoring methods related to the utilization of the local rangelands and indigenous forests. The criteria that were tested include 1) appropriateness and effectiveness in measuring change, and 2) contribution to building adaptive capacity among local land managers through learning. The criteria were assessed using a scoring system for each monitoring method in order to evaluate their strengths and weaknesses . This was done by using both quantitative and qualitative data. Contribution to building adaptive capacity was assessed by evaluating technical capacity gained, local ecological knowledge contributed and learning by participants. This was done using qualitative data. The results show that the monitoring methods had different strengths and weaknesses in relation to the criteria, making them more appropriate for different priorities such as effectively measuring change or building adaptive capacity. It is argued that an adaptive approach is a useful component in the participatory monitoring process. An adaptive framework was developed from lessons learnt in this study for collaborative monitoring. Challenges such as low literacy levels and adequate training still need to be addressed to strengthen efforts towards participatory monitoring. Factors such as incentives, conflict and local values may negatively affect the legitimacy and sustainability of participatory monitoring and therefore also need to be addressed.
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- Date Issued: 2010
Company-community participation as a conflict management strategy: a case study of AngloGold Ashanti in Mongbwalu, Democratic Republic of the Congo
- Authors: Barnett, Sarah
- Date: 2010
- Subjects: Conflict management -- Congo (Democratic Republic) , Mining corporations , Social participation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8200 , http://hdl.handle.net/10948/1265 , Conflict management -- Congo (Democratic Republic) , Mining corporations , Social participation
- Description: Mining companies operating in developing countries like the Democratic Republic of Congo (DRC) have come under increasing public criticism for not only failing to bring benefits to the country in which they operate but for often making the situation even worse through adverse environmental and social impacts. The particular focus of this treatise is the social division that a new mining project can generate between the operating company and the community living on or near to the mine site. In one area in north-eastern DRC, a large multinational mining company, AngloGold Ashanti, plans to develop a gold mine. While there have been no manifest conflicts between the company and the host community, there is evident latent conflict in the form of uncertainty and mistrust between parties. Although the company is engaged in two different models of companycommunity participation, this has either resulted in or failed to prevent tensions between the company and the local community. This research offers an exploration and discussion of the existing models of company-community participation as a conflict management strategy. With reference to relevant research and literature, as well as other available models for company-community participation, this treatise will provide a series of recommendations as to how the existing models could be made more effective in managing conflict.
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- Date Issued: 2010
Comparison of A₄ neutrino mass models
- Authors: Barry, James Munnik Hamilton
- Date: 2010
- Subjects: Neutrinos -- Mass , Standard model (Nuclear physics) , Particles (Nuclear physics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5554 , http://hdl.handle.net/10962/d1015271
- Description: The present neutrino oscillation data are compatible with tri-bimaximal mixing, to leading order. The addition of an A₄ family symmetry and extended Higgs sector to the Standard Model can generate this mixing pattern, assuming the correct vacuum expectation value alignment of Higgs scalars. The effect of deviating this alignment is studied, for different types of A₄ models, with a phenomenological emphasis: the effect of perturbations on the model predictions for the neutrino oscillation and neutrino mass observables. The standard theoretical description of neutrino oscillations is presented, along with a summary of the past, present and future experimental efforts aimed at measuring the neutrino mixing parameters. Additionally, the current constraints on the sum of absolute neutrino masses and the amplitude for neutrinoless double beta decay, which is yet to be observed, are discussed. These constraints provide a model-independent test of family symmetery models. The Standard Model is reviewed, and extensions to the Standard Model such as the seesaw mechanism(s) are discussed: these are designed to endow neutrinos with mass, and can be incorporated into A₄ symmetry models. Models with different A₄ particle assignments are analysed for deviations from tribimaximal mixing. There are nine models presented in Chapter 5, with lepton doublets transforming as 3 (underlined) and right-handed charged leptons transforming as 1, 1', 1" (all underlined) ; five of these include right-handed neutrinos transforming as 3 (underlined) and make use of the seesaw mechanism. Chapter 6 contains the analysis of six models that assign all leptons to the 3 (underlined) representation, with four of these utilising the seesaw mechanism. The models are tested for any degree of fine tuning of the parameters that define the mass matrices. The effect of perturbations on the mixing angle observables, in particular sin² ∅₁₃ and sin² ∅₂₃, is studied, as well as the effect on the Jarlskog invariant, Jcp. Investigations of the (Mee)- ∑Mv parameter space allow for comparison with current data, and can lead to the possible exclusion of a particular model by constraints from future data.
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- Date Issued: 2010
Comparison of the neuroprotective potential of theanine and minocycline
- Authors: Mpofu, Tariro Ann-Maureen
- Date: 2010 , 2010-09-20
- Subjects: Nervous system -- Degeneration -- Treatment , Tetracyclines , Antibiotics -- Side effects , Theanine -- Evaluation , Drugs -- Administration , Cerebrovascular disease -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3775 , http://hdl.handle.net/10962/d1003253 , Nervous system -- Degeneration -- Treatment , Tetracyclines , Antibiotics -- Side effects , Theanine -- Evaluation , Drugs -- Administration , Cerebrovascular disease -- Prevention
- Description: Stroke is one of the most common causes of disability and death worldwide. The most commonly experienced stroke in the clinical setting is focal ischaemia in which the middle cerebral artery (MCA) is occluded and leads to a complex series of various pathophysiological pathways that ultimately lead to neuronal cell death. Several studies have been conducted on various therapeutic agents in the search for a neuroprotective drug and various animal models have been used to carry out this research. While theanine, a component of green tea and minocycline, a tetracycline antibiotic, have been shown to possess some neuroprotective properties, the mechanisms by which these two agents carry out these effects still remains unclear. The objectives of this study were to investigate the mechanisms by which these drugs carry out these neuroprotective effects and their neuroprotective ability in a MCA occlusion model of focal ischaemia. Ischaemia leads to oxidative stress due to the imbalance of free radicals and the endogenous antioxidant defence system. An antioxidant assay using the stable 2, 2-diphenyl-1-picrylhydrazyl (DPPH●) radical was used to assess the antiradical properties of each drug. It was found that minocycline showed superior antioxidant activity in vitro when compared to theanine. Further studies on the drugs‟ ability to attenuate the Fenton reaction (in which iron catalyses the formation of reactive species) were elucidated using electrochemical analysis, UV/VIS studies, ferrozine and ferritin assays. It was found that minocycline, in contrast to theanine, was able to bind to iron ions and thus potentially prevent the participation of iron in metal catalysed radical reaction. The antioxidant activity of both drugs was further investigated by assessing their effect on cyanide-induced superoxide generation and quinolinic acid (QA)-induced lipid peroxidation (LP). Experimental evidence shows that both drugs had no significant effect on the generation of superoxide in vitro and that there was a significant decrease in LP for minocycline in vitro and theanine in vivo. The metal binding and antioxidant properties were postulated to be a possible mechanism through which these agents reduced lipid peroxidation. A study was conducted to determine the effects of the drugs on the biosynthesis of the neurotoxin, QA and it was found that minocycline increases the levels of holoenzyme activity of tryptophan-2, 3-dioxygenase (TDO) in vitro and that theanine reduces the levels of the same enzyme in vivo after treatment for 10 days. TDO is the enzyme that converts tryptophan to other products that enable enzymatic activity to change it to QA. Minocycline was thought to bring about this effect as it has been shown from preceding experimental studies that it is an effective reducing agent. Theanine on the other hand is hypothesised to bring about a reduction in holoenzyme activity by changing the binding of tryptophan to the enzyme or affecting the radicals that participate in the enzymatic degradation of tryptophan. A focal ischaemic model of stroke was induced by occluding the MCA. Histological examination of the hippocampus post -ischaemia shows a reduction in the size of the infarct after pre-treatment with minocycline only. A further study into the effects of the drugs on the generation of superoxide and on the levels of the endogenous glutathione after a stroke was carried out. Pre-treatment of the animals with either theanine or minocycline showed no significant effects on the generation of the radical species or of the endogenous antioxidant which ruled out these as a mechanism of neuroprotection of both drugs, post-ischaemia.The findings of this study provide novel information on the possible mechanisms by which both theanine and minocycline act to bring about neuroprotection. In particular in this study, pre-treatment with minocycline has shown promise in the focal ischaemic model of stroke.
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- Date Issued: 2010
Concussion in contact sport: investigating the neurocognitive profile of Afrikaans adolescent rugby players
- Authors: Horsman, Mark
- Date: 2010
- Subjects: Afrikaner students -- Intelligence testing Sports -- Psychological aspects Rugby football injuries Neural computers Neuropsychological tests Brain -- Concussion
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2994 , http://hdl.handle.net/10962/d1002503
- Description: A number of computerised tests have been especially developed to facilitate the medical management of the sports-related concussion. Probably the most widely used of these programmes is the ImPACT test that was developed in the USA and that is registered with the HPCSA for use in the South African context. A recent Afrikaans version of the test served as the basis of the present study with the following objectives: (i) to collect Afrikaans ImPACT normative data on a cohort of Afrikaans first language adolescent rugby players with Model C education for comparison with existing South African English first language adolescent rugby players with Private/Model C schooling, and (ii) to investigate the pre-versus postseason ImPACT neurocognitive test profiles of this cohort of Afrikaans first language adolescent rugby players versus equivalent noncontact sports controls. The results for Part 1 of the study generally demonstrate poorer performance in respect of the Afrikaans cohort, which is understood to be the result of poorer quality of education. The results for Part 2 demonstrated failure of the rugby group to benefit from practice on the ImPACT Visual Motor Speed composite score to the same extent as the control group. It is argued that this apparent cognitive vulnerability in the rugby group is due to lowered cognitive reserve capacity in association with long term exposure to concussive and sub-concussive injury.
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- Date Issued: 2010
Considerations on the economic impact of the 2010 FIFA World Cup on South Africa
- Authors: Menezes, Mathew Gomes
- Date: 2010
- Subjects: World Cup (Soccer) (2010) -- Economic aspects Sports -- Economic aspects -- South Africa Soccer -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:963 , http://hdl.handle.net/10962/d1002697
- Description: Mega-events are associated with significant positive implications such as enhanced international exposure of the host, improved infrastructure, increased tourist numbers, higher employment levels and tax revenues, greater feelings of patriotism among host region residents and integration of the host into the international community. Supporters of events have claimed that the occasions stimulate prominent economic gains for the host region. The economic and tourism growth that occurred in Barcelona following the 1992 Olympic Games is erroneously cited by proponents of hosting as an example of the potential benefits that an event can derive on the host. Those Games were not the sole driver of growth in the region. An analysis of previous mega-events, demonstrated that net benefits were not a necessary consequence of hosting. Comparison of pre-event estimates of the economic impact and their actual effects are universally divergent. The observation was validated by the consensus academic opinion that economic impact studies systematically overstate the benefits of hosting, and underestimate the costs. Further, different forward-looking studies of the same event, calculate vastly different predictions. The tools for calculating the economic impact, specifically Input-Output Analysis and Computable General Equilibrium, do not provide useful predictions given their dependence on the inaccurate data. With 2010 cost data having continually increased since 2003, determining the appropriate inputs to an I-O or CGE is problematic. It was identified that the weight given to the multiplier effect was also a factor in the amplification of the expected benefits. Given the poor data sets available as inputs to I-O and CGE models, the study concentrated on conducting a comprehensive Cost-Benefit Analysis of the determinants of the economic impact of the 2010 World Cup based on the premise that the identification of the relative costs and benefits of staging the event was regarded as a greater contribution to the body of knowledge on the topic. It can be expected that there will not be significant short-term economic gains; this study predicted a net cost of R8.4bn, which is marginally offset by short-term net intangible benefits. The short-term economic consequences of the 2010 World Cup are expected to be overshadowed by the long-term effects on revenues within the tourism industry. The image implication of hosting 2010 is the most salient factor in considering the economic impact of 2010, as an alteration in the national image can have long-term effects on FDI and tourism. It is however not a certainty that the international exposure that South Africa receives will be beneficial, in the instance that the World Cup is characterised by poor organisational measures or crime. The net impact of hosting is expected to be a function of the long-term benefits, which can be expected to exceed the short-terms costs, and derive a cumulative net benefit from staging 2010. The World Cup is however unlikely to stimulate the economic growth rate above levels that would have occurred had the event not been held in South Africa.
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- Date Issued: 2010
Constraints and challenges faced by small, medium and micro enterprise contractors in Malawi
- Authors: Chilipunde, Rodrick Lengama
- Date: 2010
- Subjects: Small business -- Malawi -- Management , Contractors' operations -- Malawi , Small business -- Malawi -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9686 , http://hdl.handle.net/10948/1220 , Small business -- Malawi -- Management , Contractors' operations -- Malawi , Small business -- Malawi -- Finance
- Description: Small, medium and micro enterprises (SMMEs) are an important sector of any construction economy. The need for efficient SMMEs is well documented and cannot be over-emphasised. SMMEs are vital in their contribution to employment creation and value reorientation. However, their in process operations are not well understood and have rarely been addressed. The aim of this research was therefore to establish a base level of understanding of the operational core-face of SMMEs in Malawi. The methodology used included an extensive literature review and field survey conducted on 52 SMMEs. The field survey used the questionnaire instrument and random sampling. The critical findings from the literature were that there are binding constraints in the operations of SMMEs. The field survey confirmed the issues raised in the literature and posited the operational challenges as lack of finance, training and business skills; limited skills in Construction Information Technology (IT), and prevalence of unethical conduct amongst some of the stakeholders. The findings make an invaluable contribution to the search for solutions to the problems faced by construction SMMEs in Malawi and provide insight for further research in institutional weaknesses and policy issues regarding in this part of the world. The implications of the findings are that unless the limitations named above are resolved, SMMEs in Malawi will continue to experience poor growth and competitiveness. The recommendations include the developing of training programmes in business management, introduction of sector specific financing programmes and the provision of an appropriate regulatory and legislative framework. By establishing the core issues affecting the operations of SMMEs in the Malawian construction industry, the research has contributed to the enhancement of the understanding of this elusive subject.
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- Date Issued: 2010
Constructing a web of culture: the case of akKOORd, an Overberg community choir
- Authors: Jacobs, Sunell Human
- Date: 2010
- Subjects: Choral music -- South Africa -- Overberg , Choirs (Music) , Overberg (South Africa) -- History , City and town life -- Social aspects
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:8506 , http://hdl.handle.net/10948/1254 , Choral music -- South Africa -- Overberg , Choirs (Music) , Overberg (South Africa) -- History , City and town life -- Social aspects
- Description: akKOORd, a community choir in the relatively small southern region of the Overberg, was formed in 2006, and although the choir has only a brief history, its spirit, activities, and concerts have inspired and touched many people. This qualitative study pays attention to aspects of the choir’s history, its performance practice and of the “web” of community members connected to and involved in its activities. Through interviews and personal notes this in-depth study provides a “micronarrative” of this choir within the “web” of the Overberg community itself. It aims to not only interpret this narrative with regard to the meaning behind actions and their symbolic importance in society, but also to explore its relevance in the broader context of current South African cultural discourse. During this research it became evident that policy makers and potential funders regard this predominantly white choir with its Western repertoire as a form of undesirable exclusivity and elitism. This study opposes such a point of view, contending instead that elitism in the form of excellence has the power to defy barriers of social standing and ethnicity, and to unite people through a collective sense of ownership.
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- Date Issued: 2010
Contemporary left politics in South Africa: the case of the tri-partite alliance in the Eastern Cape
- Authors: Hesjedal, Siv Helen
- Date: 2010
- Subjects: Politics, Practical -- South Africa Social classes -- South Africa -- History Political parties -- South Africa African National Congress South African Communist Party Cosatu Eastern Cape (South Africa) -- Politics and government Politics, Practical -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3295 , http://hdl.handle.net/10962/d1003083
- Description: This thesis aims to make sense of Left politics in South Africa within the Tri-partite Alliance between the ANC, SACP and COSATU. The thesis focuses on developments in the Eastern Cape, between 2000 and 2008. The thesis describes the prevalent forms of Left politics in the Eastern Cape and the tendencies in the Alliance that organise this Left. The thesis also examines the historical, social and political conditions and that shape the form and content of Left politics in the province. Based on a survey of literature on what is considered the core manifestations of Left politics globally in the 20th Century Left politics is defined as the elements of the political spectrum that are concerned with the progressive resolution of involuntary disadvantage and with a goal of abolishing class society and capitalism. Although the Alliance as a whole should be seen to be on the Left on an international political spectrum, this thesis argues that the Left/Right dichotomy is useful for understanding the politics of the Alliance, as long as the second part of this definition is taken into consideration. The Alliance Left is understood as those leaders and activists within the Alliance that have the SACP and Cosatu as their operating base. It will be argued that this Left is, in its practice, largely concerned with what insiders refer to as politics of „influence‟, rather than with politics of „structural transformation‟. It is the ANC that is the leader of the Alliance and the party in government and thus it is on the terrain of ANC strategy, policy and positions that contestation in the Alliance plays itself out. Thus, for the Left, there is strength in the idea of the Alliance. However, there are significant theoretical and political weaknesses in the Left that undermine the possibility of making good use of various corporatist platforms to pursue the agenda of the Left in the Eastern Cape. There is also increased contestation within the Alliance Left itself about the continued usefulness of this strategy.
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- Date Issued: 2010
Contextualising curriculum through issues-based approaches: a case of eco-schools in Kenya
- Authors: Epus, Joash Gregory Odeke
- Date: 2010
- Subjects: Environmental education -- Kenya -- Case studies Curriculum planning -- Kenya -- Case studies Curriculum change -- Kenya -- Case studies Environmental literacy -- Study and teaching -- Namibia -- Case studies Environmental education -- Activity programs -- Namibia -- Case studies Conservation of natural resources -- Study and teaching -- Namibia -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1463 , http://hdl.handle.net/10962/d1003344
- Description: This study involved an issues-based approach to curriculum contextualisation in the context of the Eco-Schools programme in Kenya. It adopted a two-phase design using interpretivist and socially critical research orientations. In this study, research is represented as a process which is socially constructed within a particular theoretical, contextual, social and historical context by unfolding the thesis to illuminate how the phases are closely woven into each other. The first phase used the survey method for a contextual review of existing approaches and views relating to environmental education in the formal education sector. The survey aimed to develop a deeper understanding of environmental education as currently practiced in Kenya and to unravel the complexities surrounding it. It involved about two hundred and six primary school teachers and a critical review of a set of resource materials used in Kenyan Primary Schools. It revealed that some aspects of environmental education practice and the prevailing technocratic view of curriculum in Kenyan primary schools potentially limit possibilities for issues-based approaches to curriculum contextualisation. The action research process in four case study schools in Nyanza province of Kenya represent an attempt to address issues in context through socially critical environmental education. Participant observations, workshops and document analysis revealed that, contextualised conceptions of the terms ‘environment’ and ‘environmental education’ that resulted from a process of deliberation of meaning by teachers in relation to their contexts and practices served to set perspective for the action research process. Further, the planning phase which involved environmental auditing to identify issues of concern, prioritization of actions, issues to address, and action planning to guide implementation was critical in setting the agenda of the action research process in each of the case study schools. Integration and infusion of local issues of concern into curriculum planning further enriched processes of curriculum contextualisation, making them relevant to local contexts by addressing real issues through appropriate pedagogical approaches in auditing, investigation and research, communicating and interpreting results, reflecting on investigations and taking action. The action research process further enhanced cooperation and partnership between the case study schools and surrounding communities with mutual benefits. The research report demonstrates that despite the limitations posed by the technocratic orientation of the Kenyan curriculum, it is possible to address real environmental issues, risks and associated sustainable development challenges in context through issues-based approaches to curriculum contextualisation in the context of the Eco-Schools programme.
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- Date Issued: 2010
Contrasting biodiversity values in four states of Eastern Province thornveld
- Authors: Duncan, Imogen May
- Date: 2010
- Subjects: Biodiversity -- South Africa -- Eastern Cape , Agrobiodiversity -- South Africa -- Eastern Cape , Agricultural ecology -- South Africa -- Eastern Cape , Veld -- South Africa -- Eastern Cape , Landscape assessment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4190 , http://hdl.handle.net/10962/d1003759 , Biodiversity -- South Africa -- Eastern Cape , Agrobiodiversity -- South Africa -- Eastern Cape , Agricultural ecology -- South Africa -- Eastern Cape , Veld -- South Africa -- Eastern Cape , Landscape assessment -- South Africa -- Eastern Cape
- Description: Land use and land transformation are major threats to biodiversity. Only a small percentage of land and thus biodiversity is protected within reserves. The majority of biodiversity lies in the hands of private and communal farmers and in order to protect biodiversity they must perceive it as having some value and have the means and incentive to conserve it. This study examined two things: (i) the relationship between biodiversity and measures of ecosystem health, range condition, primary production and presence of useful plants that would be expected to be of relevant use to land users, (ii) the perceptions of farmers of vegetation states that differ in the abovementioned attributes. Within the Eastern Province Thornveld of the Smaldeel area, four different vegetation states were selected for the study, namely park-like grassland with scattered Acacia karroo (“savanna”), heavily infested Acacia karroo grassland (“acacia”), thicket-grassland mosaic (“thicket”) and heavily utilised thicketgrassland in communal lands (“communal”). The four states are a consequence of different patterns of browsing and fire, in both pre-colonial and recent times. Different ecological attributes were assessed and compared for each state and the relationships between the different attributes determined. Ecosystem health, in terms of stability or resistance to erosion, infiltration/water-holding capacity, and nutrient cycling were compared using Landscape Function Analysis. The agricultural value of the different landscapes was measured using range condition assessment techniques. Plant species richness and other measures of diversity, along with their conservation and usefulness values, were compared between states. Plant productivity and biomass were compared using satellite data. The thicket state was found to be the most functional due to the added habitat complexity provided by the vegetation. It was the most biodiverse, the most useful and contained many, but not all of the important conservation species. The communal state had high biodiversity and was be fairly resilient to heavy usage, not showing the expected signs of land degradation. The savanna state, although thought of as the optimum state for cattle production, was not significantly different from the other states in terms of agricultural potential, but had the lowest values for plant diversity, browse potential, abundance of useful plant species and biomass. The acacia state had the highest and least stable values in terms of biomass production, however it was found to contain species of conservation importance. The preference that four groups of land users, namely men and women from commercial and communal farming areas, expressed for the four vegetation states was assessed using semi-structured interviews in conjunction with A3 colour photographs. The men and women from the communal areas and the men from the commercial areas valued the thicket state highly for its farming potential. The male commercial farmers also valued the savanna state highly as they perceived it as being most productive for cattle farming. Both the thicket state and the savanna state were found aesthetically pleasing by all the user groups, in line with theories of preference for modified savannas and for familiar environments. There appears to be potential for preserving biodiversity on farmland. The farmers in this study, with their very utilitarian perspective, were found to intuitively gauge the health of the landscape and recognise biodiversity as indicating good farming land. The commercial farmers were strongly influenced by economic motives and thus attracted to the savanna state, but also recognised the opportunity for a wider variety of farming activities in the thicket state. The communal farmers have a high dependence on the land for their livelihoods and preferred the thicket state for its overall usefulness. The views of the farmers indicate that the opportunity for conservation is good, however much of the thicket state lies in the communal land, where the openaccess land use system makes managing for biodiversity difficult.
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- Date Issued: 2010