Challenges for South African anthropology in the 3rd Millennium
- Authors: Palmer, Robin C G
- Date: 2009
- Language: English
- Type: Text
- Identifier: vital:6111 , http://hdl.handle.net/10962/d1008105
- Description: Towards the end of one’s career, there’s a powerful inclination to look backwards instead of forwards. You become more interested in histories, biographies and obituaries; you reflect on your own life and career. It’s not inevitable, and it can be resisted. Marshall McLuhan was well into his 50s – an obscure Canadian Eng Lit academic – when he had his vision of the nature and future of the media and anticipated a ‘global village’ that the Internet has turned into a reality since his death in 1980 (McLuhan and Powers 1989) – but more on that in due course. Cui Bono? At first I gave into the tendency to look back. Initially, for this lecture, I thought to analyse my own career in South Africa in terms of who benefited most from it: South African anthropology and my students … or me. I would call the lecture ‘Cui Bono?’ But then I realised, with Latin tags on the way out, younger colleagues and students in the audience might think I was referring to a traditional Australian greeting (Coo-ee) and an Irish philanthropist pop singer (Bono). The title would be totally mystifying to many until I explained that it meant ‘to whom the good’ – in other words, who benefits? But there were other objections to this project besides the title. Even the most postmodern of reflexive anthropologists would balk at making such a self-assessment – it was not for me to judge. Anyway, I already knew the answer: My career in South Africa has not been impeded by political harassments, imprisonment or conscription. I did make some small negligible contributions to the ‘struggle’ through writing or drawing, and I did some community service, on campus or off in the same way. At a critical stage I assisted with the process that eventually produced a national staff association, now called NTESU. The only price I have paid for these distractions from serious publishing at a critical stage of my career was deservedly slow promotion. I continue to contribute to the community mainly through membership of the older of Grahamstown’s two very active Rotary clubs. It’s all I have time for, but nothing to boast about. In sum, I’ve enjoyed what my long-term colleague and Grahamstown’s Citizen of the Year (another Rotary initiative) Michael Whisson likes to call ‘sheltered employment’ – his typically ironic way of reminding us of how privileged we academics are, doing what we enjoy, in pleasant surroundings, among intelligent colleagues and the cream of our youth, with plenty of flexi-time and opportunities for subsidized travel. And now I have benefited again by being promoted to full professor without sufficiently earning my keep through subsidies on academic outputs. Whatever I might have given back through teaching and administration the net is in my favour, and I am grateful beyond words.
- Full Text:
- Date Issued: 2009
- Authors: Palmer, Robin C G
- Date: 2009
- Language: English
- Type: Text
- Identifier: vital:6111 , http://hdl.handle.net/10962/d1008105
- Description: Towards the end of one’s career, there’s a powerful inclination to look backwards instead of forwards. You become more interested in histories, biographies and obituaries; you reflect on your own life and career. It’s not inevitable, and it can be resisted. Marshall McLuhan was well into his 50s – an obscure Canadian Eng Lit academic – when he had his vision of the nature and future of the media and anticipated a ‘global village’ that the Internet has turned into a reality since his death in 1980 (McLuhan and Powers 1989) – but more on that in due course. Cui Bono? At first I gave into the tendency to look back. Initially, for this lecture, I thought to analyse my own career in South Africa in terms of who benefited most from it: South African anthropology and my students … or me. I would call the lecture ‘Cui Bono?’ But then I realised, with Latin tags on the way out, younger colleagues and students in the audience might think I was referring to a traditional Australian greeting (Coo-ee) and an Irish philanthropist pop singer (Bono). The title would be totally mystifying to many until I explained that it meant ‘to whom the good’ – in other words, who benefits? But there were other objections to this project besides the title. Even the most postmodern of reflexive anthropologists would balk at making such a self-assessment – it was not for me to judge. Anyway, I already knew the answer: My career in South Africa has not been impeded by political harassments, imprisonment or conscription. I did make some small negligible contributions to the ‘struggle’ through writing or drawing, and I did some community service, on campus or off in the same way. At a critical stage I assisted with the process that eventually produced a national staff association, now called NTESU. The only price I have paid for these distractions from serious publishing at a critical stage of my career was deservedly slow promotion. I continue to contribute to the community mainly through membership of the older of Grahamstown’s two very active Rotary clubs. It’s all I have time for, but nothing to boast about. In sum, I’ve enjoyed what my long-term colleague and Grahamstown’s Citizen of the Year (another Rotary initiative) Michael Whisson likes to call ‘sheltered employment’ – his typically ironic way of reminding us of how privileged we academics are, doing what we enjoy, in pleasant surroundings, among intelligent colleagues and the cream of our youth, with plenty of flexi-time and opportunities for subsidized travel. And now I have benefited again by being promoted to full professor without sufficiently earning my keep through subsidies on academic outputs. Whatever I might have given back through teaching and administration the net is in my favour, and I am grateful beyond words.
- Full Text:
- Date Issued: 2009
Challenging retributivist intuitions
- Authors: Hawkes, Jonathan
- Date: 2009
- Subjects: Lex talionis Punishment -- Philosophy Restorative justice
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2711 , http://hdl.handle.net/10962/d1002841
- Description: Can punishment, a practice which involves the deliberate infliction of suffering, be justified? Retributivists and consequentialists argue that punishment can be justified, whereas abolitionists argue that it cannot. Retributivists argue that punishment is justified because wrongdoers deserve it, whereas punishment is justified for consequentialists because it is beneficial for society. A popular form of abolitionism is restorative justice, which is the view that all those affected by crime (perpetrators, victims and members of society) should be reconciled. In this thesis I argue that retributivist justifications for punishment are mistaken, and argue in favour of a consequentialist view. I also argue that consequentialism can accommodate the valuable features of restorative justice while avoiding the challenges faced by it. My arguments against retributivism will turn on a thought experiment. The experiment is designed to draw out the fundamental retributivist intuition that people who cause harm deserve to suffer harm in return, yet excludes most of the principles retributivists would use to justify the intuition. I will go on to argue that, even if the retributivist considerations did apply to the experiment, they would still not justify the claim that wrongdoers deserve to be punished. Most of the retributivist considerations are, therefore, not necessary for the intuition, and none of the considerations are sufficient for it. The retributivist considerations are, I contend, rationalisations, as the claim that wrongdoers deserve to suffer is based, not on good reasons, but on an unreliable intuition. I shall argue that the consequentialist considerations, while not being necessary, are sufficient for the claim that wrongdoers should be punished, and they should be punished, I maintain, in the interests of preventing greater harm from occurring.
- Full Text:
- Date Issued: 2009
- Authors: Hawkes, Jonathan
- Date: 2009
- Subjects: Lex talionis Punishment -- Philosophy Restorative justice
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2711 , http://hdl.handle.net/10962/d1002841
- Description: Can punishment, a practice which involves the deliberate infliction of suffering, be justified? Retributivists and consequentialists argue that punishment can be justified, whereas abolitionists argue that it cannot. Retributivists argue that punishment is justified because wrongdoers deserve it, whereas punishment is justified for consequentialists because it is beneficial for society. A popular form of abolitionism is restorative justice, which is the view that all those affected by crime (perpetrators, victims and members of society) should be reconciled. In this thesis I argue that retributivist justifications for punishment are mistaken, and argue in favour of a consequentialist view. I also argue that consequentialism can accommodate the valuable features of restorative justice while avoiding the challenges faced by it. My arguments against retributivism will turn on a thought experiment. The experiment is designed to draw out the fundamental retributivist intuition that people who cause harm deserve to suffer harm in return, yet excludes most of the principles retributivists would use to justify the intuition. I will go on to argue that, even if the retributivist considerations did apply to the experiment, they would still not justify the claim that wrongdoers deserve to be punished. Most of the retributivist considerations are, therefore, not necessary for the intuition, and none of the considerations are sufficient for it. The retributivist considerations are, I contend, rationalisations, as the claim that wrongdoers deserve to suffer is based, not on good reasons, but on an unreliable intuition. I shall argue that the consequentialist considerations, while not being necessary, are sufficient for the claim that wrongdoers should be punished, and they should be punished, I maintain, in the interests of preventing greater harm from occurring.
- Full Text:
- Date Issued: 2009
Chang liver cell line as a model for Type II Diabetes in the liver and possible reversal of this condition by an indigenous medicinal plant
- Authors: Williams, Saralene Iona
- Date: 2009
- Subjects: Diabetes -- Alternative treatment , Medicinal plants , Traditional medicine , Liver -- Diseases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10339 , http://hdl.handle.net/10948/d1016179
- Description: The incidence of Type 2 Diabetes Mellittus (T2DM) is increasing world wide. In Africa the limited access to health care and the insidious course of the disease lead to more severe illness and diabetic complications. There is a need to find alternative approaches to treatment and prevention that address the problems and needs of Africa. Sutherlandia frutescens (S.frutescens) is a traditional herbal plant with known anti-diabetic properties, the precise mechanism of action of S.frutescens is not known. In order to develop new approaches for treatment and prevention of T2DM the pathophysiology of T2DM must be understood. T2DM is the final outcome of a multi-organ disease characterized by early defects in muscle, adipocytes, hepatocytes and pancreatic β-cells. In this study the role of the liver was investigated because of its central role in glucose and lipid metabolism. It is hard to differentiate between all the influences in an in vivo model, so the aim of this study was to develop an in vitro model of T2DM in Chang liver cells and to determine if S.frutescens can reverse the state of insulin resistance in this model. Different culture media conditions were screened to identify a method that can be used as the T2DM model in Chang liver cells. Serum free medium (MCBD-201) supplemented with human diabetic serum, (2.5%-10%), high insulin concentrations (0.1μM-1μM), high fructose concentrations (1-10mM). and a combination of high insulin and high fructose was used for this screening. Chang liver cells cultured in MCBD-201 medium supplemented with 1mM fructose and 0.1μM insulin showed reduced glucose uptake and increased lipid accumulation. The effect of two S.frutescens extracts, two anti-diabetic drugs, metformin and ciglitazone, and a hypolipidemic drug ciprofibrate were determined and shown to increase glucose uptake and reduce lipid accumulation. It was postulated that exposing the cells to excess nutrients in the form of high fructose would stimulate the cells to become adipogenic and accumulate lipids, which would interfere with the glucose uptake and induce insulin resistance. Gene expression of PPARγ, PPARα, and SREBP-1 transcription factors regulating lipid metabolism was determined in Chang liver cells cultured in insulin resistance inducing medium over a 48 hour time course. The expression of PPARγ, known to stimulate adipogenesis was increased after 6, 24 and 48 hours of exposure (P(H1)<0.0001). The expression of PPARα, known to stimulate β-oxidation expression, was significantly decreased after 24 hours of exposure (P(H1)<0.0001). The presence of the plant extracts in the insulin resistance inducing media protect against this increase in adipogenesis and decrease in β-oxidation after 48 hours of exposure by increasing PPARα expression and decreasing PPARγ expression. A PCR Array was performed which identified 32 more potential molecular targets of S.frutescens. Five of the 32 targets identified with the PCR Array were validated using qRT-PCR. These genes play a role in lipid and glucose metabolism and protection against oxidative stress and inflammation. In summary a cellular model of insulin resistace in hepatocytes has been established and the capacity of S.frutescens to reverse this process has been demonstrated by acting as a dual PPARγ/α agonist. New genes have been identified in the development of insulin resistance and as targets of S.frutescens.
- Full Text:
- Date Issued: 2009
- Authors: Williams, Saralene Iona
- Date: 2009
- Subjects: Diabetes -- Alternative treatment , Medicinal plants , Traditional medicine , Liver -- Diseases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10339 , http://hdl.handle.net/10948/d1016179
- Description: The incidence of Type 2 Diabetes Mellittus (T2DM) is increasing world wide. In Africa the limited access to health care and the insidious course of the disease lead to more severe illness and diabetic complications. There is a need to find alternative approaches to treatment and prevention that address the problems and needs of Africa. Sutherlandia frutescens (S.frutescens) is a traditional herbal plant with known anti-diabetic properties, the precise mechanism of action of S.frutescens is not known. In order to develop new approaches for treatment and prevention of T2DM the pathophysiology of T2DM must be understood. T2DM is the final outcome of a multi-organ disease characterized by early defects in muscle, adipocytes, hepatocytes and pancreatic β-cells. In this study the role of the liver was investigated because of its central role in glucose and lipid metabolism. It is hard to differentiate between all the influences in an in vivo model, so the aim of this study was to develop an in vitro model of T2DM in Chang liver cells and to determine if S.frutescens can reverse the state of insulin resistance in this model. Different culture media conditions were screened to identify a method that can be used as the T2DM model in Chang liver cells. Serum free medium (MCBD-201) supplemented with human diabetic serum, (2.5%-10%), high insulin concentrations (0.1μM-1μM), high fructose concentrations (1-10mM). and a combination of high insulin and high fructose was used for this screening. Chang liver cells cultured in MCBD-201 medium supplemented with 1mM fructose and 0.1μM insulin showed reduced glucose uptake and increased lipid accumulation. The effect of two S.frutescens extracts, two anti-diabetic drugs, metformin and ciglitazone, and a hypolipidemic drug ciprofibrate were determined and shown to increase glucose uptake and reduce lipid accumulation. It was postulated that exposing the cells to excess nutrients in the form of high fructose would stimulate the cells to become adipogenic and accumulate lipids, which would interfere with the glucose uptake and induce insulin resistance. Gene expression of PPARγ, PPARα, and SREBP-1 transcription factors regulating lipid metabolism was determined in Chang liver cells cultured in insulin resistance inducing medium over a 48 hour time course. The expression of PPARγ, known to stimulate adipogenesis was increased after 6, 24 and 48 hours of exposure (P(H1)<0.0001). The expression of PPARα, known to stimulate β-oxidation expression, was significantly decreased after 24 hours of exposure (P(H1)<0.0001). The presence of the plant extracts in the insulin resistance inducing media protect against this increase in adipogenesis and decrease in β-oxidation after 48 hours of exposure by increasing PPARα expression and decreasing PPARγ expression. A PCR Array was performed which identified 32 more potential molecular targets of S.frutescens. Five of the 32 targets identified with the PCR Array were validated using qRT-PCR. These genes play a role in lipid and glucose metabolism and protection against oxidative stress and inflammation. In summary a cellular model of insulin resistace in hepatocytes has been established and the capacity of S.frutescens to reverse this process has been demonstrated by acting as a dual PPARγ/α agonist. New genes have been identified in the development of insulin resistance and as targets of S.frutescens.
- Full Text:
- Date Issued: 2009
Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex
- Authors: Van Dyk, Jacoba Susanna
- Date: 2009
- Subjects: Lignocellulose Lignocellulose -- Biotechnology Lignocellulose -- Biodegradation Plant biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3936 , http://hdl.handle.net/10962/d1003995
- Description: The biological degradation of lignocellulose into fermentable sugars for the production of liquid transportation fuels is feasible and sustainable, but equires a variety of enzymes working in synergy as lignocellulose is a complex and recalcitrant substrate. The cellulosome is a multi-enzyme complex (MEC) with a variety of cellulolytic and hemicellulolytic enzymes that appears to facilitate an enhanced synergy and efficiency, as compared to free enzymes, for the degradation of recalcitrant substrates such as lignocellulose and plant cell walls. Most of the studies on cellulosomes have focused on a few organisms; C. thermocellum, C. cellulovorans and C. cellulolyticum, and there is only limited knowledge vailable on similar complexes in other organisms. Some MECs have been identified in aerobic bacteria such as Bacillus circulans and Paenibacillus curdlanolyticus, but the nature of these MECs have not been fully elucidated. This study investigated the cellulolytic and emi-cellulolytic system of Bacillus licheniformis SVD1 with specific reference to the presence of a MEC, which has never been reported in the literature for B. licheniformis. A MEC of approximately 2,000 kDa in size, based on size exclusion chromatography using Sepharose 4B, was purified from a culture of B. licheniformis. When investigating the presence of enzyme activity in the total crude fraction as well as the MEC of a birchwood xylan culture, B. licheniformis was found to display a variety of enzyme activities on a range of substrates, although xylanases were by far the predominant enzyme activity present in both the crude and MEC fractions. Based on zymogram analysis there were three CMCases, seven xylanases, three mannanases and two pectinases in the crude fraction, while the MEC had two CMCases, seven xylanases, two mannanases and one pectinase. The pectinases in the crude could be identified as a pectin methyl esterase and a lyase, while the methyl esterase was absent in the MEC. Seventeen protein species could be detected in the MEC but only nine of these displayed activity on the substrates tested. The possible presence of a β-xylosidase in the crude fraction was deduced from thin layer chromatography (TLC) which demonstrated the production of xylose by the crude fraction. It was furthermore established that B. licheniformis SVD1 was able to regulate levels of enzyme expression based on the substrate the organism was cultured on. It was found that complexed xylanase activity had a pH optimum of between pH 6.0 and 7.0 and a temperature optimum of 55oC. Complexed xylanase activity was found to be slightly inhibited by CaCl2 and inhibited to a greater extent by EDTA. Complexed xylanase activity was further shown to be activated in the presence of xylose and xylobiose, both compounds which are products of enzymatic degradation. Ethanol was found to inhibit complexed xylanase activity. The kinetic parameters for complexed xylanase activity were measured and the Km value was calculated as 2.84 mg/ml while the maximal velocity (Vmax) was calculated as 0.146 U (μmol/min/ml). Binding studies, transmission electron microscopy (TEM) and a bioinformatic analysis was conducted to investigate whether the MEC in B. licheniformis SVD1 was a putative cellulosome. The MEC was found to be unable to bind to Avicel, but was able to bind to insoluble birchwood xylan, indicating the absence of a CBM3a domain common to cellulosomal scaffoldin proteins. TEM micrographs revealed the presence of cell surface structures on cells of B. licheniformis SVD1 cultured on cellobiose and birchwood xylan. However, it could not be established whether these cell surface structures could be ascribed to the presence of the MECs on the cell surface. Bioinformatic analysis was conducted on the available genome sequence of a different strain of B. licheniformis, namely DSM 13 and ATCC 14580. No sequence homology was found with cohesin and dockerin sequences from various cellulosomal species, indicating that these strains most likely do not encode for a cellulosome. This study described and characterised a MEC that was a functional enzyme complex and did not appear to be a mere aggregation of proteins. It displayed a variety of hemi-cellulolytic activities and the available evidence suggests that it is not a cellulosome, but should rather be termed a xylanosome. Further investigation should be carried out to determine the structural basis of this MEC.
- Full Text:
- Date Issued: 2009
- Authors: Van Dyk, Jacoba Susanna
- Date: 2009
- Subjects: Lignocellulose Lignocellulose -- Biotechnology Lignocellulose -- Biodegradation Plant biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3936 , http://hdl.handle.net/10962/d1003995
- Description: The biological degradation of lignocellulose into fermentable sugars for the production of liquid transportation fuels is feasible and sustainable, but equires a variety of enzymes working in synergy as lignocellulose is a complex and recalcitrant substrate. The cellulosome is a multi-enzyme complex (MEC) with a variety of cellulolytic and hemicellulolytic enzymes that appears to facilitate an enhanced synergy and efficiency, as compared to free enzymes, for the degradation of recalcitrant substrates such as lignocellulose and plant cell walls. Most of the studies on cellulosomes have focused on a few organisms; C. thermocellum, C. cellulovorans and C. cellulolyticum, and there is only limited knowledge vailable on similar complexes in other organisms. Some MECs have been identified in aerobic bacteria such as Bacillus circulans and Paenibacillus curdlanolyticus, but the nature of these MECs have not been fully elucidated. This study investigated the cellulolytic and emi-cellulolytic system of Bacillus licheniformis SVD1 with specific reference to the presence of a MEC, which has never been reported in the literature for B. licheniformis. A MEC of approximately 2,000 kDa in size, based on size exclusion chromatography using Sepharose 4B, was purified from a culture of B. licheniformis. When investigating the presence of enzyme activity in the total crude fraction as well as the MEC of a birchwood xylan culture, B. licheniformis was found to display a variety of enzyme activities on a range of substrates, although xylanases were by far the predominant enzyme activity present in both the crude and MEC fractions. Based on zymogram analysis there were three CMCases, seven xylanases, three mannanases and two pectinases in the crude fraction, while the MEC had two CMCases, seven xylanases, two mannanases and one pectinase. The pectinases in the crude could be identified as a pectin methyl esterase and a lyase, while the methyl esterase was absent in the MEC. Seventeen protein species could be detected in the MEC but only nine of these displayed activity on the substrates tested. The possible presence of a β-xylosidase in the crude fraction was deduced from thin layer chromatography (TLC) which demonstrated the production of xylose by the crude fraction. It was furthermore established that B. licheniformis SVD1 was able to regulate levels of enzyme expression based on the substrate the organism was cultured on. It was found that complexed xylanase activity had a pH optimum of between pH 6.0 and 7.0 and a temperature optimum of 55oC. Complexed xylanase activity was found to be slightly inhibited by CaCl2 and inhibited to a greater extent by EDTA. Complexed xylanase activity was further shown to be activated in the presence of xylose and xylobiose, both compounds which are products of enzymatic degradation. Ethanol was found to inhibit complexed xylanase activity. The kinetic parameters for complexed xylanase activity were measured and the Km value was calculated as 2.84 mg/ml while the maximal velocity (Vmax) was calculated as 0.146 U (μmol/min/ml). Binding studies, transmission electron microscopy (TEM) and a bioinformatic analysis was conducted to investigate whether the MEC in B. licheniformis SVD1 was a putative cellulosome. The MEC was found to be unable to bind to Avicel, but was able to bind to insoluble birchwood xylan, indicating the absence of a CBM3a domain common to cellulosomal scaffoldin proteins. TEM micrographs revealed the presence of cell surface structures on cells of B. licheniformis SVD1 cultured on cellobiose and birchwood xylan. However, it could not be established whether these cell surface structures could be ascribed to the presence of the MECs on the cell surface. Bioinformatic analysis was conducted on the available genome sequence of a different strain of B. licheniformis, namely DSM 13 and ATCC 14580. No sequence homology was found with cohesin and dockerin sequences from various cellulosomal species, indicating that these strains most likely do not encode for a cellulosome. This study described and characterised a MEC that was a functional enzyme complex and did not appear to be a mere aggregation of proteins. It displayed a variety of hemi-cellulolytic activities and the available evidence suggests that it is not a cellulosome, but should rather be termed a xylanosome. Further investigation should be carried out to determine the structural basis of this MEC.
- Full Text:
- Date Issued: 2009
Characterisation of the plasmodium falciparum Hsp40 chaperones and their partnerships with Hsp70
- Authors: Botha, Melissa
- Date: 2009
- Subjects: Heat shock proteins Plasmodium falciparum Protein folding Molecular chaperones Malaria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3938 , http://hdl.handle.net/10962/d1003997
- Description: Central to this research, 40 kDa Heat shock proteins (Hsp40s) are known to partner (or cochaperone) 70 kDa Heat shock proteins (Hsp70s), facilitating the selection and transfer of protein substrate to Hsp70 and the stimulation of the protein folding ability of Hsp70. Members of the diverse Hsp70-Hsp40 protein complement of Plasmodium falciparum have been implicated in the cytoprotection of this malaria parasite, and are thought to facilitate the protein folding, assembly and translocation tasks required by the parasite to commandeer the infected human erythrocyte subsequent to invasion. In particular, the parasite has evolved an expanded and specialised 43- member suite of Hsp40 proteins, 19 of which bear an identifiable export motif for secretion into the infected erythrocyte cytoplasm where they potentially interact with human Hsp70. Although type I Hsp40 proteins are representative of typical regulators of Hsp70 activity, only two of these proteins are apparent in the parasite’s Hsp40 complement. These include a characteristic type I Hsp40 termed PfHsp40, and a larger, atypical type I Hsp40 termed Pfj1. Both Hsp40 proteins are predicted to be parasite-resident and are most likely to facilitate the co-chaperone regulation of the highly abundant and stress-inducible Hsp70 homolog, PfHsp70-I. In this work, the co-chaperone functionality of PfHsp40 and Pfj1 was elucidated using in vivo and in vitro assays. Purified recombinant PfHsp40 was shown to stimulate the ATPase activity of PfHsp70-I in in vitro single turnover and steady state ATPase assays, and co-operate with PfHsp70-I in in vitro aggregation suppression assays. In these in vitro assays, heterologous partnerships could be demonstrated between PfHsp70-I and the human Hsp40, Hsj1a, and human Hsp70 and PfHsp40, suggesting a common mode of Hsp70-Hsp40 interaction in the parasite and host organism. The functionality of the signature Hsp40 domain, the Jdomain, of Pfj1 was demonstrated by its ability to replace the equivalent domain of the A. tumefaciens Hsp40, Agt DnaJ, in interactions with the prokaryotic Hsp70, DnaK, in the thermosensitive dnaJ cbpA E. coli OD259 deletion strain. An H33Q mutation introduced into the invariant and crucial HPD tripeptide motif abrogated the functionality of the J-domain in the in vivo complementation system. These findings provide the first evidence for the conservation of the prototypical mode of J-domain based interaction of Hsp40 with Hsp70 in P. falciparum. Immunofluorescence staining revealed the localisation of PfHsp40 to the parasite cytoplasm, and Pfj1 to the parasite cytoplasm and nucleus in cultured intraerythrocytic stage P. falciparum parasites. PfHsp70-I was also shown to localise to the parasite cytoplasm and nucleus in these stages, consistent with the literature. Overall we propose that PfHsp40 and Pfj1 co-localise with and regulate the chaperone activity of PfHsp70-I in P. falciparum. This is the first study to identify and provide evidence for a functional Hsp70-Hsp40 partnership in P. falciparum, and provides a platform for future studies to elucidate the importance of these chaperone partnerships in the establishment and survival of the parasite in the intraerythrocytic-stages of development.
- Full Text:
- Date Issued: 2009
- Authors: Botha, Melissa
- Date: 2009
- Subjects: Heat shock proteins Plasmodium falciparum Protein folding Molecular chaperones Malaria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3938 , http://hdl.handle.net/10962/d1003997
- Description: Central to this research, 40 kDa Heat shock proteins (Hsp40s) are known to partner (or cochaperone) 70 kDa Heat shock proteins (Hsp70s), facilitating the selection and transfer of protein substrate to Hsp70 and the stimulation of the protein folding ability of Hsp70. Members of the diverse Hsp70-Hsp40 protein complement of Plasmodium falciparum have been implicated in the cytoprotection of this malaria parasite, and are thought to facilitate the protein folding, assembly and translocation tasks required by the parasite to commandeer the infected human erythrocyte subsequent to invasion. In particular, the parasite has evolved an expanded and specialised 43- member suite of Hsp40 proteins, 19 of which bear an identifiable export motif for secretion into the infected erythrocyte cytoplasm where they potentially interact with human Hsp70. Although type I Hsp40 proteins are representative of typical regulators of Hsp70 activity, only two of these proteins are apparent in the parasite’s Hsp40 complement. These include a characteristic type I Hsp40 termed PfHsp40, and a larger, atypical type I Hsp40 termed Pfj1. Both Hsp40 proteins are predicted to be parasite-resident and are most likely to facilitate the co-chaperone regulation of the highly abundant and stress-inducible Hsp70 homolog, PfHsp70-I. In this work, the co-chaperone functionality of PfHsp40 and Pfj1 was elucidated using in vivo and in vitro assays. Purified recombinant PfHsp40 was shown to stimulate the ATPase activity of PfHsp70-I in in vitro single turnover and steady state ATPase assays, and co-operate with PfHsp70-I in in vitro aggregation suppression assays. In these in vitro assays, heterologous partnerships could be demonstrated between PfHsp70-I and the human Hsp40, Hsj1a, and human Hsp70 and PfHsp40, suggesting a common mode of Hsp70-Hsp40 interaction in the parasite and host organism. The functionality of the signature Hsp40 domain, the Jdomain, of Pfj1 was demonstrated by its ability to replace the equivalent domain of the A. tumefaciens Hsp40, Agt DnaJ, in interactions with the prokaryotic Hsp70, DnaK, in the thermosensitive dnaJ cbpA E. coli OD259 deletion strain. An H33Q mutation introduced into the invariant and crucial HPD tripeptide motif abrogated the functionality of the J-domain in the in vivo complementation system. These findings provide the first evidence for the conservation of the prototypical mode of J-domain based interaction of Hsp40 with Hsp70 in P. falciparum. Immunofluorescence staining revealed the localisation of PfHsp40 to the parasite cytoplasm, and Pfj1 to the parasite cytoplasm and nucleus in cultured intraerythrocytic stage P. falciparum parasites. PfHsp70-I was also shown to localise to the parasite cytoplasm and nucleus in these stages, consistent with the literature. Overall we propose that PfHsp40 and Pfj1 co-localise with and regulate the chaperone activity of PfHsp70-I in P. falciparum. This is the first study to identify and provide evidence for a functional Hsp70-Hsp40 partnership in P. falciparum, and provides a platform for future studies to elucidate the importance of these chaperone partnerships in the establishment and survival of the parasite in the intraerythrocytic-stages of development.
- Full Text:
- Date Issued: 2009
Characterisation of Trypanosomal Type III and Type IV Hsp40 proteins
- Louw, Cassandra Alexandrovna
- Authors: Louw, Cassandra Alexandrovna
- Date: 2009
- Subjects: Trypanosoma Heat shock proteins African trypanosomiasis Epidemic encephalitis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3926 , http://hdl.handle.net/10962/d1003985
- Description: The heat shock protein-70 (Hsp70) family of molecular chaperones are ubiquitous highly conserved proteins that are critical for the viability of cellular homeostasis. The ATPase activity of Hsp70 proteins is critical to their function as the affinity of a given Hsp70 for non-native substrate is modulated by ATP binding and hydrolysis. When bound to ATP, Hsp70s possess a low affinity for a given substrate protein, while the hydrolysis of ATP to ADP causes a conformational change that results in a high affinity for substrate proteins. The basal ATPase activity of Hsp70s is too low to facilitate their function in vivo, and co-chaperones are essential to modulate the efficient protein folding by Hsp70. Heat shock protein-40 (Hsp40) heat shock proteins are essential for the in vivo function of Hsp70s by stimulating the ATPase activity of these proteins and facilitating transfer of substrates. The Type III class of Hsp40 proteins have not been well characterised due to their poor levels of conservation at the primary sequence level. This is due to the fact that Type III Hsp40s only contain a J-domain and a poorly conserved C-terminal region. The newly identified Type IV class of Hsp40s, contain an abrogated HPD tripeptide motif in the J-domain and have also not been extensively studied. Trypanosoma brucei (T. brucei) is a unicellular flagellated protozoan parasite. It is the causative agent of Human African Trypansomiasis (HAT) which results in thousands of deaths and devastating agricultural losses in many parts of Africa. T. brucei undergoes a complex lifecycle that is characterised by the transition from an insect vector to a mammalian host in markedly different conditions of temperature, pH, nutrient availability and respiratory requirements. It has been proposed that molecular chaperones may enhance the survival of these parasites due to their cytoprotective effect in combating cellular stress. Due to the fact that T. brucei infection is invariably fatal if left untreated, and that no novel treatment regimens have been developed recently, the identification of potential novel drug targets among proteins essential to the parasite’s survival in the host organism is an attractive aspect of T. brucei research. Because Type III Hsp40s are poorly conserved with respect to Hsp40s found in the human host, the identification of any of these proteins found to be essential to T. brucei survival in humans could potentially make attractive novel drug targets. An in depth in silico investigation into the Type III Hsp40 complement as well as partner Hsp70 proteins in T.brucei was performed. T. brucei possesses 65 Hsp40 proteins, of which 47 were classed as Type III and 6 of which were identified as being putative Type IV Hsp40s. A small but significant number (5) of Type III TbHsp40s contained tetratricopeptide (TPR) domains in addition to the J-domain. The J-domains of the Type III TbHsp40 complement were found to be conserved with respect to those of canonical Hsp40 proteins, although the mutation of certain residues that play a key role in Hsp40-Hsp70 interaction was noted. Potential partnerships of these proteins in the parasite was also investigated. The coding regions of three previously uncharacterised TbHsp40s were successfully amplified from T. brucei TREU927 genomic DNA and cloned into an expression vector. Tbj1, a Tcj1 ortholog, was selected for further study and successfully expressed and biochemically characterised. Tbj1 expressed in E. coli was found to be insoluble, but large amounts were recovered with the aid of a denaturing purification followed by refolding elution strategies, and the bulk of the protein recovered was in compact monomeric form as determined by size-exclusion chromatography fast protein liquid chromatography (SEC-FPLC). The addition of Tbj1 to a thermally aggregated substrate resulted in increased levels of aggregation, although Tbj1 was able to assist two Hsp70 proteins in the suppression of aggregation. Tbj1 proved unable to stimulate the ATPase activity of these same Hsp70s, and could not rescue temperature sensitive cells when replacing E.coli DnaJ and CbpA. It was concluded that Tbj1 does not possess independent chaperone activity, but could display Hsp40 co-chaperone properties under certain circumstances. This could allude to a specialised function in the T. brucei parasite. The lack of human orthologues to Tbj1 could result in the attractiveness of this protein as a novel drug target.
- Full Text:
- Date Issued: 2009
- Authors: Louw, Cassandra Alexandrovna
- Date: 2009
- Subjects: Trypanosoma Heat shock proteins African trypanosomiasis Epidemic encephalitis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3926 , http://hdl.handle.net/10962/d1003985
- Description: The heat shock protein-70 (Hsp70) family of molecular chaperones are ubiquitous highly conserved proteins that are critical for the viability of cellular homeostasis. The ATPase activity of Hsp70 proteins is critical to their function as the affinity of a given Hsp70 for non-native substrate is modulated by ATP binding and hydrolysis. When bound to ATP, Hsp70s possess a low affinity for a given substrate protein, while the hydrolysis of ATP to ADP causes a conformational change that results in a high affinity for substrate proteins. The basal ATPase activity of Hsp70s is too low to facilitate their function in vivo, and co-chaperones are essential to modulate the efficient protein folding by Hsp70. Heat shock protein-40 (Hsp40) heat shock proteins are essential for the in vivo function of Hsp70s by stimulating the ATPase activity of these proteins and facilitating transfer of substrates. The Type III class of Hsp40 proteins have not been well characterised due to their poor levels of conservation at the primary sequence level. This is due to the fact that Type III Hsp40s only contain a J-domain and a poorly conserved C-terminal region. The newly identified Type IV class of Hsp40s, contain an abrogated HPD tripeptide motif in the J-domain and have also not been extensively studied. Trypanosoma brucei (T. brucei) is a unicellular flagellated protozoan parasite. It is the causative agent of Human African Trypansomiasis (HAT) which results in thousands of deaths and devastating agricultural losses in many parts of Africa. T. brucei undergoes a complex lifecycle that is characterised by the transition from an insect vector to a mammalian host in markedly different conditions of temperature, pH, nutrient availability and respiratory requirements. It has been proposed that molecular chaperones may enhance the survival of these parasites due to their cytoprotective effect in combating cellular stress. Due to the fact that T. brucei infection is invariably fatal if left untreated, and that no novel treatment regimens have been developed recently, the identification of potential novel drug targets among proteins essential to the parasite’s survival in the host organism is an attractive aspect of T. brucei research. Because Type III Hsp40s are poorly conserved with respect to Hsp40s found in the human host, the identification of any of these proteins found to be essential to T. brucei survival in humans could potentially make attractive novel drug targets. An in depth in silico investigation into the Type III Hsp40 complement as well as partner Hsp70 proteins in T.brucei was performed. T. brucei possesses 65 Hsp40 proteins, of which 47 were classed as Type III and 6 of which were identified as being putative Type IV Hsp40s. A small but significant number (5) of Type III TbHsp40s contained tetratricopeptide (TPR) domains in addition to the J-domain. The J-domains of the Type III TbHsp40 complement were found to be conserved with respect to those of canonical Hsp40 proteins, although the mutation of certain residues that play a key role in Hsp40-Hsp70 interaction was noted. Potential partnerships of these proteins in the parasite was also investigated. The coding regions of three previously uncharacterised TbHsp40s were successfully amplified from T. brucei TREU927 genomic DNA and cloned into an expression vector. Tbj1, a Tcj1 ortholog, was selected for further study and successfully expressed and biochemically characterised. Tbj1 expressed in E. coli was found to be insoluble, but large amounts were recovered with the aid of a denaturing purification followed by refolding elution strategies, and the bulk of the protein recovered was in compact monomeric form as determined by size-exclusion chromatography fast protein liquid chromatography (SEC-FPLC). The addition of Tbj1 to a thermally aggregated substrate resulted in increased levels of aggregation, although Tbj1 was able to assist two Hsp70 proteins in the suppression of aggregation. Tbj1 proved unable to stimulate the ATPase activity of these same Hsp70s, and could not rescue temperature sensitive cells when replacing E.coli DnaJ and CbpA. It was concluded that Tbj1 does not possess independent chaperone activity, but could display Hsp40 co-chaperone properties under certain circumstances. This could allude to a specialised function in the T. brucei parasite. The lack of human orthologues to Tbj1 could result in the attractiveness of this protein as a novel drug target.
- Full Text:
- Date Issued: 2009
Characterization of hydrogen and helium implanted silicon carbide
- Authors: O'Connell, Jacques Herman
- Date: 2009
- Subjects: Silicon carbide , Hydrogen , Helium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10539 , http://hdl.handle.net/10948/979 , Silicon carbide , Hydrogen , Helium
- Description: This dissertation focuses on the characterization of hydrogen implanted 3C-SiC and helium implanted 6H-SiC and the interaction of silver and palladium with the SiC. The main technique used for the analysis of the implanted SiC was transmission electron microscopy (TEM), although scanning electron microscopy (SEM) and nanoindentation hardness testing were also used. Both H and He implantations were done at an ion energy of 100 keV and the total dose for both species was 1017 ions/cm2. Specimens were annealed at 1000 °C for 20 min in an inert atmosphere. The observed depth of ion damage agreed closely with that predicted by TRIM 2008. The damaged region in the He implanted specimens had a high density of small bubbles but no cracks were observed. Severe cracking was observed along the damaged region in the H implanted specimens. A second phase hexagonal (4H-SiC) was detected in two grains in the 3C-SiC and some grown in voids were also observed. The wettability of SiC by a 2:1 by volume mixture of Ag and Pd is extremely low but is significantly increased through the addition of Si to the mixture. The Si containing metal mixture was found to migrate along the grain boundaries of polycrystalline 3CSiC while sealing the point of entry. Pd attacks SiC and severe etching was observed on the surface of 6H-SiC. An epitaxially orientated Pd2Si inclusion was observed in the 6H-SiC. No effect of implantation damage on the interaction of Pd and Ag with SiC was observed. Pd etched the surface of the He implanted 6H-SiC down through the damaged region with no evidence of implantation damage left after 67 hours of annealing and thus no conclusions could be drawn. The metal mixture interacted with the non implanted surface of the H implanted 3C-SiC after dissolving the Si substrate and therefore the effect of the ion damage on the interaction could not be investigated. Nanoindentation hardness measurements showed a marked increase in hardness of He implanted 6H-SiC annealed for 20 min at 1000 °C over that of as implanted and virgin material. There was also a large decrease in hardness corresponding to the depth of the ion damage.
- Full Text:
- Date Issued: 2009
- Authors: O'Connell, Jacques Herman
- Date: 2009
- Subjects: Silicon carbide , Hydrogen , Helium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10539 , http://hdl.handle.net/10948/979 , Silicon carbide , Hydrogen , Helium
- Description: This dissertation focuses on the characterization of hydrogen implanted 3C-SiC and helium implanted 6H-SiC and the interaction of silver and palladium with the SiC. The main technique used for the analysis of the implanted SiC was transmission electron microscopy (TEM), although scanning electron microscopy (SEM) and nanoindentation hardness testing were also used. Both H and He implantations were done at an ion energy of 100 keV and the total dose for both species was 1017 ions/cm2. Specimens were annealed at 1000 °C for 20 min in an inert atmosphere. The observed depth of ion damage agreed closely with that predicted by TRIM 2008. The damaged region in the He implanted specimens had a high density of small bubbles but no cracks were observed. Severe cracking was observed along the damaged region in the H implanted specimens. A second phase hexagonal (4H-SiC) was detected in two grains in the 3C-SiC and some grown in voids were also observed. The wettability of SiC by a 2:1 by volume mixture of Ag and Pd is extremely low but is significantly increased through the addition of Si to the mixture. The Si containing metal mixture was found to migrate along the grain boundaries of polycrystalline 3CSiC while sealing the point of entry. Pd attacks SiC and severe etching was observed on the surface of 6H-SiC. An epitaxially orientated Pd2Si inclusion was observed in the 6H-SiC. No effect of implantation damage on the interaction of Pd and Ag with SiC was observed. Pd etched the surface of the He implanted 6H-SiC down through the damaged region with no evidence of implantation damage left after 67 hours of annealing and thus no conclusions could be drawn. The metal mixture interacted with the non implanted surface of the H implanted 3C-SiC after dissolving the Si substrate and therefore the effect of the ion damage on the interaction could not be investigated. Nanoindentation hardness measurements showed a marked increase in hardness of He implanted 6H-SiC annealed for 20 min at 1000 °C over that of as implanted and virgin material. There was also a large decrease in hardness corresponding to the depth of the ion damage.
- Full Text:
- Date Issued: 2009
Characterization of manganese tetraarylthiosubstituted phthalocyanines self assembled monolayers
- Matemadombo, Fungisai, Durmus, Mahmut, Togo, Chamunorwa, Limson, Janice L, Nyokong, Tebello
- Authors: Matemadombo, Fungisai , Durmus, Mahmut , Togo, Chamunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263364 , vital:53621 , xlink:href="https://doi.org/10.1016/j.electacta.2009.04.059"
- Description: Manganese tetraarylthiosubstituted phthalocyanines (complexes 1–5) have been deposited on Au electrode surfaces through the self assembled monolayer (SAM) technique. SAM characteristics reported in this work are: ion barrier factor (∼1); interfacial capacitance (303–539 μF cm−2) and surface coverage (1.06 × 10−10–2.80 × 10−10 mol cm−2). Atomic force microscopy was employed in characterizing a SAM. SAMs of complexes 1–5 were employed to detect L-cysteine (with limit of detection ranging from 2.83 × 10−7 to 3.14 × 10−7 M at potentials of 0.68–0.75 V vs. Ag|AgCl) and nitrite (limit of detection ranging from 1.78 × 10−7 to 3.02 × 10−7 M at potentials of 0.69–0.76 V vs. Ag|AgCl).
- Full Text:
- Date Issued: 2009
- Authors: Matemadombo, Fungisai , Durmus, Mahmut , Togo, Chamunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263364 , vital:53621 , xlink:href="https://doi.org/10.1016/j.electacta.2009.04.059"
- Description: Manganese tetraarylthiosubstituted phthalocyanines (complexes 1–5) have been deposited on Au electrode surfaces through the self assembled monolayer (SAM) technique. SAM characteristics reported in this work are: ion barrier factor (∼1); interfacial capacitance (303–539 μF cm−2) and surface coverage (1.06 × 10−10–2.80 × 10−10 mol cm−2). Atomic force microscopy was employed in characterizing a SAM. SAMs of complexes 1–5 were employed to detect L-cysteine (with limit of detection ranging from 2.83 × 10−7 to 3.14 × 10−7 M at potentials of 0.68–0.75 V vs. Ag|AgCl) and nitrite (limit of detection ranging from 1.78 × 10−7 to 3.02 × 10−7 M at potentials of 0.69–0.76 V vs. Ag|AgCl).
- Full Text:
- Date Issued: 2009
Characterization of nickel tetrahydroxy phthalocyanine complexes and the electrocatalytic oxidation of 4-chlorophenol
- Khene, Samson M, Lobb, Kevin A, Nyokong, Tebello
- Authors: Khene, Samson M , Lobb, Kevin A , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263308 , vital:53616 , xlink:href="https://doi.org/10.1016/j.ica.2009.08.019"
- Description: This work reports on the use of nickel(II) tetrahydroxy (NiPc(OH)4) and (poly-Ni(OH)Pc(OH)4) phthalocyanine complexes as films on ordinary poly graphite electrode (OPGE) for the electrochemical oxidation of 4-chlorophenol (4-CP). The NiPc(OH)4 film was electrotransformed to Ni(OH)Pc(OH)4 film in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridge form. The result showed that the Ni(OH)Pc(OH)4 film on OPGE was more electroactive in terms of increase in current and less catalytic in terms of potential compared to the adsorbed NiPc(OH)4 on OPGE. The reactivity of the two molecules was explained by theoretical calculations. The energies of the frontier orbitals of NiPc(OH)4, Ni(OH)Pc(OH)4 and 4-chlorophenol were calculated using density functional theory (DFT) method. The inter molecular hardness (η) and donor–acceptor hardness (ηDA) of Ni(OH)Pc(OH)4, NiPc(OH)4, Ni(OH)Pc(OH)4/4-chlorophenol and NiPc(OH)4/4-chlorophenol were estimated. The Ni(OH)Pc(OH)4, showed stronger interaction with 4-chlorophenol than NiPc(OH)4. DFT method was also used to model IR and Raman spectrum of H2Pc(OH)4 and NiPc(OH)4.
- Full Text:
- Date Issued: 2009
- Authors: Khene, Samson M , Lobb, Kevin A , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263308 , vital:53616 , xlink:href="https://doi.org/10.1016/j.ica.2009.08.019"
- Description: This work reports on the use of nickel(II) tetrahydroxy (NiPc(OH)4) and (poly-Ni(OH)Pc(OH)4) phthalocyanine complexes as films on ordinary poly graphite electrode (OPGE) for the electrochemical oxidation of 4-chlorophenol (4-CP). The NiPc(OH)4 film was electrotransformed to Ni(OH)Pc(OH)4 film in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridge form. The result showed that the Ni(OH)Pc(OH)4 film on OPGE was more electroactive in terms of increase in current and less catalytic in terms of potential compared to the adsorbed NiPc(OH)4 on OPGE. The reactivity of the two molecules was explained by theoretical calculations. The energies of the frontier orbitals of NiPc(OH)4, Ni(OH)Pc(OH)4 and 4-chlorophenol were calculated using density functional theory (DFT) method. The inter molecular hardness (η) and donor–acceptor hardness (ηDA) of Ni(OH)Pc(OH)4, NiPc(OH)4, Ni(OH)Pc(OH)4/4-chlorophenol and NiPc(OH)4/4-chlorophenol were estimated. The Ni(OH)Pc(OH)4, showed stronger interaction with 4-chlorophenol than NiPc(OH)4. DFT method was also used to model IR and Raman spectrum of H2Pc(OH)4 and NiPc(OH)4.
- Full Text:
- Date Issued: 2009
Characterization of polymeric film of a new manganese phthalocyanine complex octa-substituted with 2-diethylaminoethanethiol, and its use for the electrochemical detection of bentazon
- Akinbulu, Isaac A, Nyokong, Tebello
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262568 , vital:53534 , xlink:href="https://doi.org/10.1016/j.electacta.2009.07.074"
- Description: Manganese acetate octakis-(2-diethyaminoethanethiol) phthalocyanine (AcMnODEAETPc) was newly synthesized and characterized by spectroscopic and electrochemical methods. Solution electrochemistry of the complex showed three redox processes assigned to MnIIIPc−1/MnIIIPc−2, MnIIIPc−2/MnIIPc−2 and MnIIPc−2/MnIIPc−3 species. The new molecule was polymerized onto a glassy carbon electrode (GCE) to form thin films of different thickness, giving poly-10-AcMnODEAETPc-GCE, poly-20-AcMnODEAETPc-GCE and poly-30-AcMnODEAETPc-GCE, where 10, 20 and 30 represent the number of voltammetry scans during polymerization. Three distinct redox processes were observed on the modified electrode in 0.1 M phosphate buffer solution, pH 5, which confirmed the formation of the polymer. The current signal due to the herbicide, bentazon, was dependent on film thickness; the best signal was obtained on poly-20-AcMnODEAETPc-GCE while poly-10-AcMnODEAETPc-GCE gave the least signal. However, the signals due to the herbicide were better on the different films compared to the bare electrode. Electrochemical impedance spectroscopy (EIS) technique revealed that differences in film thickness offered different charge transfer resistances, Rct, hence difference in current signals for bentazon oxidation were observed on these films. A Tafel slope of 77 mV/decade, obtained for the herbicide on poly-20-AcMnODEAETPc-GCE, denotes a fast one electron transfer followed by a slow chemical step in the electro-oxidation of bentazon. The voltammetry signals of the herbicide on the films indicated the likely involvement of ring-based redox processes in the detection of the herbicide. A plot of background corrected current response, on this film, versus the concentration of bentazon was linear within the range 50–750 μM with a detection limit of 2.48 × 10−7 M.
- Full Text:
- Date Issued: 2009
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262568 , vital:53534 , xlink:href="https://doi.org/10.1016/j.electacta.2009.07.074"
- Description: Manganese acetate octakis-(2-diethyaminoethanethiol) phthalocyanine (AcMnODEAETPc) was newly synthesized and characterized by spectroscopic and electrochemical methods. Solution electrochemistry of the complex showed three redox processes assigned to MnIIIPc−1/MnIIIPc−2, MnIIIPc−2/MnIIPc−2 and MnIIPc−2/MnIIPc−3 species. The new molecule was polymerized onto a glassy carbon electrode (GCE) to form thin films of different thickness, giving poly-10-AcMnODEAETPc-GCE, poly-20-AcMnODEAETPc-GCE and poly-30-AcMnODEAETPc-GCE, where 10, 20 and 30 represent the number of voltammetry scans during polymerization. Three distinct redox processes were observed on the modified electrode in 0.1 M phosphate buffer solution, pH 5, which confirmed the formation of the polymer. The current signal due to the herbicide, bentazon, was dependent on film thickness; the best signal was obtained on poly-20-AcMnODEAETPc-GCE while poly-10-AcMnODEAETPc-GCE gave the least signal. However, the signals due to the herbicide were better on the different films compared to the bare electrode. Electrochemical impedance spectroscopy (EIS) technique revealed that differences in film thickness offered different charge transfer resistances, Rct, hence difference in current signals for bentazon oxidation were observed on these films. A Tafel slope of 77 mV/decade, obtained for the herbicide on poly-20-AcMnODEAETPc-GCE, denotes a fast one electron transfer followed by a slow chemical step in the electro-oxidation of bentazon. The voltammetry signals of the herbicide on the films indicated the likely involvement of ring-based redox processes in the detection of the herbicide. A plot of background corrected current response, on this film, versus the concentration of bentazon was linear within the range 50–750 μM with a detection limit of 2.48 × 10−7 M.
- Full Text:
- Date Issued: 2009
Children navigating rural poverty: Rural children's use of wild resources to counteract food insecurity in the Eastern Cape, South Africa
- McGarry, Dylan K, Shackleton, Charlie M
- Authors: McGarry, Dylan K , Shackleton, Charlie M
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181191 , vital:43706 , xlink:href="https://doi.org/10.1080/10796120802677594"
- Description: This paper analyzes the role of natural resources in the lives of rural children experiencing heightened vulnerability to poverty and the impact of HIV/AIDS, a subject that previously has been unexplored. The authors highlight wild-food use by rural children as a regular activity that supplements their domestic diets. Over the course of 18 months in the Eastern Cape of South Africa, the authors used a broad quantitative and qualitative methodology to explore the food acquisition and consumption patterns for 850 children. They found that the quality of children's domestic diets was, on average, 60% lower than the Food and Agricultural Organization (FAO) guidelines. This occurred in a population where 62% of the children surveyed were supplementing their diets with wild foods; and 30% with over half their diet supplemented in this way. Significantly, dietary diversity increased by 13% when wild food supplementation occurred. Another result was the commercialization of wild foods (observed among 47% of the children), wherein significantly more vulnerable children sold these foods. Considering the heightened nutritional and energy needs of children, combined with the impact of poverty and HIV/AIDS on household food access, wild foods represent the last freely attainable food sources available to them.
- Full Text:
- Date Issued: 2009
- Authors: McGarry, Dylan K , Shackleton, Charlie M
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181191 , vital:43706 , xlink:href="https://doi.org/10.1080/10796120802677594"
- Description: This paper analyzes the role of natural resources in the lives of rural children experiencing heightened vulnerability to poverty and the impact of HIV/AIDS, a subject that previously has been unexplored. The authors highlight wild-food use by rural children as a regular activity that supplements their domestic diets. Over the course of 18 months in the Eastern Cape of South Africa, the authors used a broad quantitative and qualitative methodology to explore the food acquisition and consumption patterns for 850 children. They found that the quality of children's domestic diets was, on average, 60% lower than the Food and Agricultural Organization (FAO) guidelines. This occurred in a population where 62% of the children surveyed were supplementing their diets with wild foods; and 30% with over half their diet supplemented in this way. Significantly, dietary diversity increased by 13% when wild food supplementation occurred. Another result was the commercialization of wild foods (observed among 47% of the children), wherein significantly more vulnerable children sold these foods. Considering the heightened nutritional and energy needs of children, combined with the impact of poverty and HIV/AIDS on household food access, wild foods represent the last freely attainable food sources available to them.
- Full Text:
- Date Issued: 2009
Citizen participation, decentralization and inclusive development : a survey on citizen participation and decentralization in South Africa with specific reference to the Eastern Cape c.2005
- Authors: Robino, Carolina
- Date: 2009
- Subjects: Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9084 , http://hdl.handle.net/10948/875 , Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Description: Contemporary debates about development confer a prominent role to citizen participation and decentralization. Growing scepticism about the efficacy of narrowly conceived measures add pressure to reform development both theoretically and in practical terms. There is a greater understanding that ‘traditional’ development approaches and policies need to be reformulated and decentralization and citizen participation have been proposed as remedies to previous development failures. It is frequently argued that citizen participation will improve the efficiency and efficacy of public services. Citizen participation is meant to render local government more accountable and to contribute to deepening democracy, by reinforcing representative democratic institutions with participatory forms. At the same time, decentralization reforms have been proposed as a response to the failures of highly centralized states. From a political perspective, it is argued, decentralization reforms can help the central state gain legitimacy and have been seen as a strategy for maintaining political stability. It has been repeatedly suggested that physical proximity makes it easier for citizens to hold local officials accountable for their performance. From an economic perspective, decentralization can improve the match between the mix of services provided by the public sector and the preferences of the local population. It has also been noted that people are more willing to pay for services that respond to their priorities and that increased competition between local governments generates spaces for more creative responses adapted to local needs. But then, can decentralization and citizen participation live up to the faith and expectations that they have inspired? I argue that the literature commonly over-emphasises the role of citizen participation and decentralization in development and what these processes and reforms can achieve. Much of the evidence is anecdotal in nature and tends to neglect the specific contexts in which these processes take place. Also largely ignored are political economy considerations and a critical exploration of the relationship between these two key words. At best, when their interrelationships are addressed decentralization and citizen participation are conceived as based on a symbiotic relationship. I suggest, however, that the relationship between these two processes is not as straightforward as most of the literature assumes. The meanings of these two key words in current development lexicon are explored and critically assessed. I argue that whether or not the rising prominence of these two words actually means the emergence of a new development agenda is a moot point. It critically depends on the understandings of these ambiguous terms. The thesis adopts a political economy approach. Combined with this is an awareness of the broader historical and socio-economic context in which citizen participation and decentralization take place. The thesis applies these ideas triangulating diverse research methods and data sources. It combines a literature review and documentary analysis, a survey conducted with municipal authorities and civil society organizations in the Eastern Cape as well as structured interviews with Ward councillors and with key informants. From a theoretical perspective, the study lays a foundation for understanding the relationship between development policies outcomes and the nature of citizen participation and decentralization in developing countries. This, in turn, provides a basis from which citizen participation and decentralization in South Africa can be assessed and understood. The thesis presents evidence from a case study of the Eastern Cape, South Africa. By revealing how different dimensions of decentralization and citizen participation operate and intersect, the findings demonstrate, that contrary to common knowledge, citizen participation and decentralization are frequently at odds. Moreover, contrary to frequent statements, the research also shows that opening new spaces for participation in decentralized local governance can result in fewer changes and disappointing results at best, undermining the transformative potential of the concepts of participation and decentralization.
- Full Text:
- Date Issued: 2009
- Authors: Robino, Carolina
- Date: 2009
- Subjects: Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9084 , http://hdl.handle.net/10948/875 , Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Description: Contemporary debates about development confer a prominent role to citizen participation and decentralization. Growing scepticism about the efficacy of narrowly conceived measures add pressure to reform development both theoretically and in practical terms. There is a greater understanding that ‘traditional’ development approaches and policies need to be reformulated and decentralization and citizen participation have been proposed as remedies to previous development failures. It is frequently argued that citizen participation will improve the efficiency and efficacy of public services. Citizen participation is meant to render local government more accountable and to contribute to deepening democracy, by reinforcing representative democratic institutions with participatory forms. At the same time, decentralization reforms have been proposed as a response to the failures of highly centralized states. From a political perspective, it is argued, decentralization reforms can help the central state gain legitimacy and have been seen as a strategy for maintaining political stability. It has been repeatedly suggested that physical proximity makes it easier for citizens to hold local officials accountable for their performance. From an economic perspective, decentralization can improve the match between the mix of services provided by the public sector and the preferences of the local population. It has also been noted that people are more willing to pay for services that respond to their priorities and that increased competition between local governments generates spaces for more creative responses adapted to local needs. But then, can decentralization and citizen participation live up to the faith and expectations that they have inspired? I argue that the literature commonly over-emphasises the role of citizen participation and decentralization in development and what these processes and reforms can achieve. Much of the evidence is anecdotal in nature and tends to neglect the specific contexts in which these processes take place. Also largely ignored are political economy considerations and a critical exploration of the relationship between these two key words. At best, when their interrelationships are addressed decentralization and citizen participation are conceived as based on a symbiotic relationship. I suggest, however, that the relationship between these two processes is not as straightforward as most of the literature assumes. The meanings of these two key words in current development lexicon are explored and critically assessed. I argue that whether or not the rising prominence of these two words actually means the emergence of a new development agenda is a moot point. It critically depends on the understandings of these ambiguous terms. The thesis adopts a political economy approach. Combined with this is an awareness of the broader historical and socio-economic context in which citizen participation and decentralization take place. The thesis applies these ideas triangulating diverse research methods and data sources. It combines a literature review and documentary analysis, a survey conducted with municipal authorities and civil society organizations in the Eastern Cape as well as structured interviews with Ward councillors and with key informants. From a theoretical perspective, the study lays a foundation for understanding the relationship between development policies outcomes and the nature of citizen participation and decentralization in developing countries. This, in turn, provides a basis from which citizen participation and decentralization in South Africa can be assessed and understood. The thesis presents evidence from a case study of the Eastern Cape, South Africa. By revealing how different dimensions of decentralization and citizen participation operate and intersect, the findings demonstrate, that contrary to common knowledge, citizen participation and decentralization are frequently at odds. Moreover, contrary to frequent statements, the research also shows that opening new spaces for participation in decentralized local governance can result in fewer changes and disappointing results at best, undermining the transformative potential of the concepts of participation and decentralization.
- Full Text:
- Date Issued: 2009
Civil engineering components for a conceptual elevated light rail transit model with reference to Nelson Mandela Bay
- Authors: Zang, Jin
- Date: 2009
- Subjects: Railroads, Local and light -- South Africa -- Port Elizabeth , Street-railroads -- South Africa -- Port Elizabeth , Local transit -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9593 , http://hdl.handle.net/10948/769 , Railroads, Local and light -- South Africa -- Port Elizabeth , Street-railroads -- South Africa -- Port Elizabeth , Local transit -- South Africa -- Port Elizabeth
- Description: The increase of motor vehicles, especially in cities, cause transport problems of traffic congestion, vehicle accidents, air pollution and a lack of public spaces. The increasing number of motor vehicles consumes huge amounts of finite petrol energy and emits large amounts of gases that are harmful to the atmosphere and the natural environment. Therefore, the current road transport network is not a sustainable form of public transport for the future. In order to seek a suitable transportation mode, the Infrastructure and Engineering Business Unit of the Nelson Mandela Bay Municipality (NMBM) did some feasibility studies about light rail transit (LRT) from 1984 to 1988. The NMBM-report (1988: 8) concluded that a LRT system would provide the most suitable and primary mode to serve Nelson Mandela Bay (NMB). Although LRT was regarded as the most suitable primary mode of transport at that time (1988), further studies that were reported in 2006 recommended an alternative public transportation system. This research refers to these studies done for the NMB area and other studies and reports for other areas, but focus on the identification of the most suitable civil engineering components for a conceptual elevated light rail transit (ELRT) model. Electrical driven LRT systems have advantages over internal-combustion driven vehicles in terms of environmental protection. Traditional LRT systems are at ground level and are integrated with the existing road network. Some successful LRT systems indicate that the success of LRT systems is mainly dependent on integration with the existing road network. However, the integration of road transport systems with LRT systems cause increased congestion and accidents. An ELRT system can solve these problems. Bangkok has already built an ELRT system to solve its severe traffic congestion. 4 In order to develop a conceptual ELRT model, this research aimed to determine the most suitable civil engineering components for a conceptual ELRT model, including: (i) the most suitable type of bridge foundation; (ii) the most suitable type bridge girder; (iii) the most suitable type of sleeper; and (iv) whether the track should be a ballasted or non-ballasted type. The grounded theory approach was adopted to build up sets of data from which the most suitable components could be selected. In addition, design analyses were done of the various types of components to determine their suitability for a conceptual ELRT model. Experienced engineers and experts were also consulted to identify the most suitable components. After analyses and selection of the most suitable components, outstanding experts were approached to evaluate the components that showed up as the most suitable through the research. The research results indicated that bored and cast-in-place piles, a double-cell trapezoidal segmental box girder, and twin-block sleepers on a non-ballasted sleeper bed are the most suitable civil engineering components.
- Full Text:
- Date Issued: 2009
- Authors: Zang, Jin
- Date: 2009
- Subjects: Railroads, Local and light -- South Africa -- Port Elizabeth , Street-railroads -- South Africa -- Port Elizabeth , Local transit -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9593 , http://hdl.handle.net/10948/769 , Railroads, Local and light -- South Africa -- Port Elizabeth , Street-railroads -- South Africa -- Port Elizabeth , Local transit -- South Africa -- Port Elizabeth
- Description: The increase of motor vehicles, especially in cities, cause transport problems of traffic congestion, vehicle accidents, air pollution and a lack of public spaces. The increasing number of motor vehicles consumes huge amounts of finite petrol energy and emits large amounts of gases that are harmful to the atmosphere and the natural environment. Therefore, the current road transport network is not a sustainable form of public transport for the future. In order to seek a suitable transportation mode, the Infrastructure and Engineering Business Unit of the Nelson Mandela Bay Municipality (NMBM) did some feasibility studies about light rail transit (LRT) from 1984 to 1988. The NMBM-report (1988: 8) concluded that a LRT system would provide the most suitable and primary mode to serve Nelson Mandela Bay (NMB). Although LRT was regarded as the most suitable primary mode of transport at that time (1988), further studies that were reported in 2006 recommended an alternative public transportation system. This research refers to these studies done for the NMB area and other studies and reports for other areas, but focus on the identification of the most suitable civil engineering components for a conceptual elevated light rail transit (ELRT) model. Electrical driven LRT systems have advantages over internal-combustion driven vehicles in terms of environmental protection. Traditional LRT systems are at ground level and are integrated with the existing road network. Some successful LRT systems indicate that the success of LRT systems is mainly dependent on integration with the existing road network. However, the integration of road transport systems with LRT systems cause increased congestion and accidents. An ELRT system can solve these problems. Bangkok has already built an ELRT system to solve its severe traffic congestion. 4 In order to develop a conceptual ELRT model, this research aimed to determine the most suitable civil engineering components for a conceptual ELRT model, including: (i) the most suitable type of bridge foundation; (ii) the most suitable type bridge girder; (iii) the most suitable type of sleeper; and (iv) whether the track should be a ballasted or non-ballasted type. The grounded theory approach was adopted to build up sets of data from which the most suitable components could be selected. In addition, design analyses were done of the various types of components to determine their suitability for a conceptual ELRT model. Experienced engineers and experts were also consulted to identify the most suitable components. After analyses and selection of the most suitable components, outstanding experts were approached to evaluate the components that showed up as the most suitable through the research. The research results indicated that bored and cast-in-place piles, a double-cell trapezoidal segmental box girder, and twin-block sleepers on a non-ballasted sleeper bed are the most suitable civil engineering components.
- Full Text:
- Date Issued: 2009
Civil liability of an employer for injuries on duty
- Authors: Brandt, Denver Charles
- Date: 2009
- Subjects: Liability (Law) -- South Africa , Employers' liability -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10195 , http://hdl.handle.net/10948/1042 , Liability (Law) -- South Africa , Employers' liability -- South Africa , Labor laws and legislation -- South Africa
- Description: The workplace has evolved dramatically in the past decades. Technology has improved, innovative ways of utilising nuclear power have been developed, new chemicals have been introduced to the market and the adverse effects of other chemicals on both human health and safety and the environment have been discovered. This has influenced the nature of the workplace itself. While employees enjoy a common law right to a safe working environment and health and safety, state intervention currently provides restricted claims to an employee who has sustained injuries or contracted occupational diseases. This thesis explores the effect of section 35 of the Compensation for Occupational Injuries and Diseases Act 130 of 1993 which deprives an employee of its common law right to institute civil action against an employer for an injury sustained or disease contracted during the course and scope of employment. Furthermore, this thesis also explores the marriage between the Occupational Health and Safety Act 89 of 1993 and the Compensation for Occupational Injuries and Diseases Act 130 of 1993 as well as the position of ‘employee’ and ‘employer’ insofar as the scope and application of these two acts are concerned with specific reference to the position of labour broker employees. The use of indemnity clauses and its validity in South Africa will also be explored and discussed. This thesis also dedicates a chapter to the leading case authority of Jooste v Score Supermarket Trading (Pty) Ltd and its effect insofar as the enforcement and application of section 35 of the Compensation for Occupational Injuries and Diseases Act 130 of 1993 is concerned. It is impossible to mention all the changes in the workplace that have occurred in the recent years, and this discussion therefore focuses on the current position of employees who have been deprived of their common law right to institute delictual action for damages resulting from an injury sustained while on duty as well as the impact of the current restrictive claims available to them. Alterations to existing approaches are also proposed to resurrect the common law right of employees to institute action against their employers. , Abstract
- Full Text:
- Date Issued: 2009
- Authors: Brandt, Denver Charles
- Date: 2009
- Subjects: Liability (Law) -- South Africa , Employers' liability -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10195 , http://hdl.handle.net/10948/1042 , Liability (Law) -- South Africa , Employers' liability -- South Africa , Labor laws and legislation -- South Africa
- Description: The workplace has evolved dramatically in the past decades. Technology has improved, innovative ways of utilising nuclear power have been developed, new chemicals have been introduced to the market and the adverse effects of other chemicals on both human health and safety and the environment have been discovered. This has influenced the nature of the workplace itself. While employees enjoy a common law right to a safe working environment and health and safety, state intervention currently provides restricted claims to an employee who has sustained injuries or contracted occupational diseases. This thesis explores the effect of section 35 of the Compensation for Occupational Injuries and Diseases Act 130 of 1993 which deprives an employee of its common law right to institute civil action against an employer for an injury sustained or disease contracted during the course and scope of employment. Furthermore, this thesis also explores the marriage between the Occupational Health and Safety Act 89 of 1993 and the Compensation for Occupational Injuries and Diseases Act 130 of 1993 as well as the position of ‘employee’ and ‘employer’ insofar as the scope and application of these two acts are concerned with specific reference to the position of labour broker employees. The use of indemnity clauses and its validity in South Africa will also be explored and discussed. This thesis also dedicates a chapter to the leading case authority of Jooste v Score Supermarket Trading (Pty) Ltd and its effect insofar as the enforcement and application of section 35 of the Compensation for Occupational Injuries and Diseases Act 130 of 1993 is concerned. It is impossible to mention all the changes in the workplace that have occurred in the recent years, and this discussion therefore focuses on the current position of employees who have been deprived of their common law right to institute delictual action for damages resulting from an injury sustained while on duty as well as the impact of the current restrictive claims available to them. Alterations to existing approaches are also proposed to resurrect the common law right of employees to institute action against their employers. , Abstract
- Full Text:
- Date Issued: 2009
Civil society's quest for democracy in Zimbabwe: origins,barriers and prospects, 1900-2008
- Authors: Magure, Booker
- Date: 2009
- Subjects: Civil Society -- Zimbabwe Zimbabwe -- Politics and government -- 1980 Zimbabwe -- Economic conditions Zimbabwe -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2798 , http://hdl.handle.net/10962/d1003008
- Description: This thesis is a critical examination of the origins, barriers and prospects for a working class-led civil society as it sought to democratise Zimbabwe’s post-colonial state. It is an interdisciplinary but historically informed analysis of how advanced capitalist development promoted the emergence of social movement unionism with a potentiality to advance democracy in Zimbabwe. Despite occurring on a much smaller and thinner scale, the evolution of civil society in colonial Zimbabwe was akin to what happened in 19th century Britain where capitalist expansion presented a foundation for democratisation. However, big underlying barriers exist in Zimbabwe, resulting from various forms of authoritarian structures and forcible mobilisation strategies emanating from colonialism and the protracted war of liberation. ZANU PF’s violent reaction to memory contests by non-participants in the war of liberation seeking an alternative political agenda attest to the controversial and polemical nature of struggles over memory and forgetting in contemporary Zimbabwean politics. These structural impediments forestalled the organic growth of civil society in Zimbabwe, thereby explaining its inchoate status and the failure to significantly determine the course of public policy. While recognising the democratic aspirations and capacities of the working class in precipitating political change, this thesis takes into consideration the impact of other factors on state-society relations. These include deepening state barbarism, globalisation, and technological advances in communication, transnational civil society, a dysfunctional economy, migration and remittances. Finally this thesis presents an optimistic scenario about the prospects for civil society and democratisation in Zimbabwe. I argue that the revival of the productive sectors of the economy can possibly strengthen the labour movement and revive its capacities for ushering in a democracy.
- Full Text:
- Date Issued: 2009
- Authors: Magure, Booker
- Date: 2009
- Subjects: Civil Society -- Zimbabwe Zimbabwe -- Politics and government -- 1980 Zimbabwe -- Economic conditions Zimbabwe -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2798 , http://hdl.handle.net/10962/d1003008
- Description: This thesis is a critical examination of the origins, barriers and prospects for a working class-led civil society as it sought to democratise Zimbabwe’s post-colonial state. It is an interdisciplinary but historically informed analysis of how advanced capitalist development promoted the emergence of social movement unionism with a potentiality to advance democracy in Zimbabwe. Despite occurring on a much smaller and thinner scale, the evolution of civil society in colonial Zimbabwe was akin to what happened in 19th century Britain where capitalist expansion presented a foundation for democratisation. However, big underlying barriers exist in Zimbabwe, resulting from various forms of authoritarian structures and forcible mobilisation strategies emanating from colonialism and the protracted war of liberation. ZANU PF’s violent reaction to memory contests by non-participants in the war of liberation seeking an alternative political agenda attest to the controversial and polemical nature of struggles over memory and forgetting in contemporary Zimbabwean politics. These structural impediments forestalled the organic growth of civil society in Zimbabwe, thereby explaining its inchoate status and the failure to significantly determine the course of public policy. While recognising the democratic aspirations and capacities of the working class in precipitating political change, this thesis takes into consideration the impact of other factors on state-society relations. These include deepening state barbarism, globalisation, and technological advances in communication, transnational civil society, a dysfunctional economy, migration and remittances. Finally this thesis presents an optimistic scenario about the prospects for civil society and democratisation in Zimbabwe. I argue that the revival of the productive sectors of the economy can possibly strengthen the labour movement and revive its capacities for ushering in a democracy.
- Full Text:
- Date Issued: 2009
Clem Sunter's transformational leadership discourse: a linguistic analysis
- Authors: Eley, Georgina Jane
- Date: 2009
- Subjects: Linguistics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/61994 , vital:28093
- Description: Since the 1970s, two distinct leadership styles have been recognised in the fields of business and organisational research - transactional and transformational leadership. Transactional leadership is seen to resemble managerial-type leadership where followers fulfil their duties in return for rewards that satisfy their self-interest, such as pay or promotion. Transformational leadership, as the label suggests, is leadership that is seen to transform followers from their everyday selves to their better selves (Yukl 1998). Transformational leaders motivate followers by appealing to their higher-order needs, offering incentives for compliance such as feelings of personal empowerment, a sense of moral self-actualisation and an emphasis on the individual's contribution to the community at large (Harvey 2004). These leaders have been observed to emerge and thrive within contexts fraught with socio-political and economic turbulence, where they maximise the uncertainty of the environment to instigate change. Transformational leaders are seen to be especially adept at using discourse to foster strong, persuasive interpersonal relations with their followers. This research reports on, particularly, the interpersonal dimension of Clem Sunter's transformational discourse; he being a prominent South African scenario planner and business leader. It is essentially a qualitative study that describes Sunter's discourse in three of his texts written in 1996. The end to Apartheid in 1994 and transition from White to Black governance meant that the socio-political climate of 1996 South Africa was conducive to the rise of a transformational leader like Sunter. Although the country was, ostensibly, a democracy in 1996, much social transformation was still needed at the time Sunter produced his texts. The analysis are grounded mainly in Systemic Functional Linguistics, specifically APPRAISAL theory and, to some extent, Critical Discourse Analysis theory. However, the analyses do not follow a classic CDA analysis approach, but draw rather from more recent CDA work (cf. Fairclough 2003), such as the analysis of value assumption types within the texts. This analysis clearly demonstrates that Sunter's discourse is congruent 11 with the principal insights of transformational leadership. More than this, it is argued that these findings suggest a close link between transformational leadership and the goals of the latest social order of new capitalism, a link not made in the relevant research to date. The analysis of modes of operation of ideology in the texts (cf. Thompson 1990), also deriving from CDA, reinforces this, indicating that Sunter's transformational discourse promotes and maintains the kinds of power inequalities that underpin new capitalism. The APPRAISAL analysis of Affect choices in the text reveals a high frequency of disquiet, i.e. Sunter's discourse is seen to generate feelings of insecurity and fear. This feature, interestingly, is completely inconsistent with current transformational leadership theory, but would have been an effective motivational technique given the instability of the South African socio-political context in 1996. In addition, the APPRAISAL analysis of Judgement reveals that Sunter evokes high levels of tenacity and appeals to readers' morality, ethics and feelings of group-efficacy - all higher-order needs. The argument here too is that the socio-political context enabled Sunter to stimulate disquiet and tenacity in an effective configuration to mobilise change in his reader and promote the goals of new capitalism. The thesis concludes with a reflection on the limitations of the study and makes various recommendations for future research.
- Full Text:
- Date Issued: 2009
- Authors: Eley, Georgina Jane
- Date: 2009
- Subjects: Linguistics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/61994 , vital:28093
- Description: Since the 1970s, two distinct leadership styles have been recognised in the fields of business and organisational research - transactional and transformational leadership. Transactional leadership is seen to resemble managerial-type leadership where followers fulfil their duties in return for rewards that satisfy their self-interest, such as pay or promotion. Transformational leadership, as the label suggests, is leadership that is seen to transform followers from their everyday selves to their better selves (Yukl 1998). Transformational leaders motivate followers by appealing to their higher-order needs, offering incentives for compliance such as feelings of personal empowerment, a sense of moral self-actualisation and an emphasis on the individual's contribution to the community at large (Harvey 2004). These leaders have been observed to emerge and thrive within contexts fraught with socio-political and economic turbulence, where they maximise the uncertainty of the environment to instigate change. Transformational leaders are seen to be especially adept at using discourse to foster strong, persuasive interpersonal relations with their followers. This research reports on, particularly, the interpersonal dimension of Clem Sunter's transformational discourse; he being a prominent South African scenario planner and business leader. It is essentially a qualitative study that describes Sunter's discourse in three of his texts written in 1996. The end to Apartheid in 1994 and transition from White to Black governance meant that the socio-political climate of 1996 South Africa was conducive to the rise of a transformational leader like Sunter. Although the country was, ostensibly, a democracy in 1996, much social transformation was still needed at the time Sunter produced his texts. The analysis are grounded mainly in Systemic Functional Linguistics, specifically APPRAISAL theory and, to some extent, Critical Discourse Analysis theory. However, the analyses do not follow a classic CDA analysis approach, but draw rather from more recent CDA work (cf. Fairclough 2003), such as the analysis of value assumption types within the texts. This analysis clearly demonstrates that Sunter's discourse is congruent 11 with the principal insights of transformational leadership. More than this, it is argued that these findings suggest a close link between transformational leadership and the goals of the latest social order of new capitalism, a link not made in the relevant research to date. The analysis of modes of operation of ideology in the texts (cf. Thompson 1990), also deriving from CDA, reinforces this, indicating that Sunter's transformational discourse promotes and maintains the kinds of power inequalities that underpin new capitalism. The APPRAISAL analysis of Affect choices in the text reveals a high frequency of disquiet, i.e. Sunter's discourse is seen to generate feelings of insecurity and fear. This feature, interestingly, is completely inconsistent with current transformational leadership theory, but would have been an effective motivational technique given the instability of the South African socio-political context in 1996. In addition, the APPRAISAL analysis of Judgement reveals that Sunter evokes high levels of tenacity and appeals to readers' morality, ethics and feelings of group-efficacy - all higher-order needs. The argument here too is that the socio-political context enabled Sunter to stimulate disquiet and tenacity in an effective configuration to mobilise change in his reader and promote the goals of new capitalism. The thesis concludes with a reflection on the limitations of the study and makes various recommendations for future research.
- Full Text:
- Date Issued: 2009
Clustering algorithms and their effect on edge preservation in image compression
- Authors: Ndebele, Nothando Elizabeth
- Date: 2009
- Subjects: Image compression , Vector analysis , Cluster analysis , Cluster anaylsis -- Data processing , Algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5576 , http://hdl.handle.net/10962/d1008210 , Image compression , Vector analysis , Cluster analysis , Cluster anaylsis -- Data processing , Algorithms
- Description: Image compression aims to reduce the amount of data that is stored or transmitted for images. One technique that may be used to this end is vector quantization. Vectors may be used to represent images. Vector quantization reduces the number of vectors required for an image by representing a cluster of similar vectors by one typical vector that is part of a set of vectors referred to as the code book. For compression, for each image vector, only the closest codebook vector is stored or transmitted. For reconstruction, the image vectors are again replaced by the the closest codebook vectors. Hence vector quantization is a lossy compression technique and the quality of the reconstructed image depends strongly on the quality of the codebook. The design of the codebook is therefore an important part of the process. In this thesis we examine three clustering algorithms which can be used for codebook design in image compression: c-means (CM), fuzzy c-means (FCM) and learning vector quantization (LVQ). We give a description of these algorithms and their application to codebook design. Edges are an important part of the visual information contained in an image. It is essential therefore to use codebooks which allow an accurate representation of the edges. One of the shortcomings of using vector quantization is poor edge representation. We therefore carry out experiments using these algorithms to compare their edge preserving qualities. We also investigate the combination of these algorithms with classified vector quantization (CVQ) and the replication method (RM). Both these methods have been suggested as methods for improving edge representation. We use a cross validation approach to estimate the mean squared error to measure the performance of each of the algorithms and the edge preserving methods. The results reflect that the edges are less accurately represented than the non - edge areas when using CM, FCM and LVQ. The advantage of using CVQ is that the time taken for code book design is reduced particularly for CM and FCM. RM is found to be effective where the codebook is trained using a set that has larger proportions of edges than the test set.
- Full Text:
- Date Issued: 2009
- Authors: Ndebele, Nothando Elizabeth
- Date: 2009
- Subjects: Image compression , Vector analysis , Cluster analysis , Cluster anaylsis -- Data processing , Algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5576 , http://hdl.handle.net/10962/d1008210 , Image compression , Vector analysis , Cluster analysis , Cluster anaylsis -- Data processing , Algorithms
- Description: Image compression aims to reduce the amount of data that is stored or transmitted for images. One technique that may be used to this end is vector quantization. Vectors may be used to represent images. Vector quantization reduces the number of vectors required for an image by representing a cluster of similar vectors by one typical vector that is part of a set of vectors referred to as the code book. For compression, for each image vector, only the closest codebook vector is stored or transmitted. For reconstruction, the image vectors are again replaced by the the closest codebook vectors. Hence vector quantization is a lossy compression technique and the quality of the reconstructed image depends strongly on the quality of the codebook. The design of the codebook is therefore an important part of the process. In this thesis we examine three clustering algorithms which can be used for codebook design in image compression: c-means (CM), fuzzy c-means (FCM) and learning vector quantization (LVQ). We give a description of these algorithms and their application to codebook design. Edges are an important part of the visual information contained in an image. It is essential therefore to use codebooks which allow an accurate representation of the edges. One of the shortcomings of using vector quantization is poor edge representation. We therefore carry out experiments using these algorithms to compare their edge preserving qualities. We also investigate the combination of these algorithms with classified vector quantization (CVQ) and the replication method (RM). Both these methods have been suggested as methods for improving edge representation. We use a cross validation approach to estimate the mean squared error to measure the performance of each of the algorithms and the edge preserving methods. The results reflect that the edges are less accurately represented than the non - edge areas when using CM, FCM and LVQ. The advantage of using CVQ is that the time taken for code book design is reduced particularly for CM and FCM. RM is found to be effective where the codebook is trained using a set that has larger proportions of edges than the test set.
- Full Text:
- Date Issued: 2009
Collective forgiving
- Authors: Hamilton, Kelly
- Date: 2009
- Subjects: Forgiveness -- Philosophy Collective behavior -- Philosophy Retribution -- Philosophy Reconciliation -- Philosophy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2709 , http://hdl.handle.net/10962/d1002839
- Description: Forgiveness is traditionally understood as a personal change of heart, in which an individual victim of a wrongdoing overcomes her resentment towards the perpetrator of that wrongdoing. Peter Strawson (1974) famously argued that resentment is a personal participant retributive reactive attitude, and the overcoming of such an attitude through forgiveness is itself a personal reactive attitude – in other words, forgiveness is an affective response to a wrongdoing by an individual victim, that is devoid of a retributive element. Because reactive attitudes are personal, it is argued that collectives – groups of individuals – cannot forgive, since collectives cannot, as collectives, hold reactive attitudes. I argue against this. I show that it is possible for collectives to hold attitudes in a way that is not reducible to individuals holding attitudes as individuals, and yet these attitudes still remain personal. Individuals exist within communities, and are interdependent on one another. Much of an individual‟s beliefs and attitudes depend on the collectives that she is a part of. I argue that an attitude is collective when it is deemed to be the appropriate attitude for members of the collective to hold. Members of the collective will take this attitude on as their own insofar as they identify themselves as members of the collective. Individuals hold the attitude, making the attitude personal, but since the individuals hold the attitude in virtue of their membership to a collective, the attitude is also collective. Given that forgiveness is itself a reactive attitude, and that collectives can hold attitudes, I argue that it is possible for a collective to forgive. Members of a collective will come to forgive when forgiveness is held up as the appropriate attitude for them, and once enough members have taken on the attitude of forgiveness as their own attitude, a collective can be said to have forgiven.
- Full Text:
- Date Issued: 2009
- Authors: Hamilton, Kelly
- Date: 2009
- Subjects: Forgiveness -- Philosophy Collective behavior -- Philosophy Retribution -- Philosophy Reconciliation -- Philosophy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2709 , http://hdl.handle.net/10962/d1002839
- Description: Forgiveness is traditionally understood as a personal change of heart, in which an individual victim of a wrongdoing overcomes her resentment towards the perpetrator of that wrongdoing. Peter Strawson (1974) famously argued that resentment is a personal participant retributive reactive attitude, and the overcoming of such an attitude through forgiveness is itself a personal reactive attitude – in other words, forgiveness is an affective response to a wrongdoing by an individual victim, that is devoid of a retributive element. Because reactive attitudes are personal, it is argued that collectives – groups of individuals – cannot forgive, since collectives cannot, as collectives, hold reactive attitudes. I argue against this. I show that it is possible for collectives to hold attitudes in a way that is not reducible to individuals holding attitudes as individuals, and yet these attitudes still remain personal. Individuals exist within communities, and are interdependent on one another. Much of an individual‟s beliefs and attitudes depend on the collectives that she is a part of. I argue that an attitude is collective when it is deemed to be the appropriate attitude for members of the collective to hold. Members of the collective will take this attitude on as their own insofar as they identify themselves as members of the collective. Individuals hold the attitude, making the attitude personal, but since the individuals hold the attitude in virtue of their membership to a collective, the attitude is also collective. Given that forgiveness is itself a reactive attitude, and that collectives can hold attitudes, I argue that it is possible for a collective to forgive. Members of a collective will come to forgive when forgiveness is held up as the appropriate attitude for them, and once enough members have taken on the attitude of forgiveness as their own attitude, a collective can be said to have forgiven.
- Full Text:
- Date Issued: 2009
Community participation in solid waste management in high-density low-income areas: the case of C-Section in Duncan Village
- Authors: Mazinyo, Sonwabo Perez
- Date: 2009
- Subjects: Refuse and refuse disposal -- South Africa -- Eastern Cape , Sewage disposal -- South Africa -- Eastern Cape , Low-income housing -- South Africa -- Eastern Cape , Social participation -- South Africa -- Eastern Cape , Conflict management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil (Environmental Studies)
- Identifier: vital:11875 , http://hdl.handle.net/10353/261 , Refuse and refuse disposal -- South Africa -- Eastern Cape , Sewage disposal -- South Africa -- Eastern Cape , Low-income housing -- South Africa -- Eastern Cape , Social participation -- South Africa -- Eastern Cape , Conflict management -- South Africa -- Eastern Cape
- Description: Solid waste management in high density low-income areas is a problem that manifests itself in ubiquitous illegal dumpsites and unhealthy living environmental conditions. Community participation in solid waste management in Duncan Village, C-Section has been found to be part of the solution to this problem. This study investigates community participation in SWM at household level, community waste project level and at informal salvaging/scavenging level. The integration of community participation into existing Buffalo City Municipality waste management plans and the nature of the relationship between the different interest groups are investigated. This study employs qualitative research methods where interviews and participatory observations are used to investigate key objectives. The nature of the relationships between councillors, C-Section residents and the Buffalo City Municipality Departments are tenuous and fraught with conflicts. These conflicts emerge due to the lack of communication as well as due to the non-integration of the community interest groups‟ views and activities into solid waste management in C-Section. The study suggests that this lack of communication should be addressed and that integrated participation of all stakeholders must be encouraged for effective solid waste management in a high density low-income community.
- Full Text:
- Date Issued: 2009
- Authors: Mazinyo, Sonwabo Perez
- Date: 2009
- Subjects: Refuse and refuse disposal -- South Africa -- Eastern Cape , Sewage disposal -- South Africa -- Eastern Cape , Low-income housing -- South Africa -- Eastern Cape , Social participation -- South Africa -- Eastern Cape , Conflict management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil (Environmental Studies)
- Identifier: vital:11875 , http://hdl.handle.net/10353/261 , Refuse and refuse disposal -- South Africa -- Eastern Cape , Sewage disposal -- South Africa -- Eastern Cape , Low-income housing -- South Africa -- Eastern Cape , Social participation -- South Africa -- Eastern Cape , Conflict management -- South Africa -- Eastern Cape
- Description: Solid waste management in high density low-income areas is a problem that manifests itself in ubiquitous illegal dumpsites and unhealthy living environmental conditions. Community participation in solid waste management in Duncan Village, C-Section has been found to be part of the solution to this problem. This study investigates community participation in SWM at household level, community waste project level and at informal salvaging/scavenging level. The integration of community participation into existing Buffalo City Municipality waste management plans and the nature of the relationship between the different interest groups are investigated. This study employs qualitative research methods where interviews and participatory observations are used to investigate key objectives. The nature of the relationships between councillors, C-Section residents and the Buffalo City Municipality Departments are tenuous and fraught with conflicts. These conflicts emerge due to the lack of communication as well as due to the non-integration of the community interest groups‟ views and activities into solid waste management in C-Section. The study suggests that this lack of communication should be addressed and that integrated participation of all stakeholders must be encouraged for effective solid waste management in a high density low-income community.
- Full Text:
- Date Issued: 2009
Comparative electrocatalytic behavior of self-assembled monolayer of thiol derivatised Co (II) phthalocyanines on gold disk, ultramicro cylinder and fiber electrodes
- Nombona, Nolwazi, Geraldo, Daniela A, Hakuzimana, Jean, Schwarz, Anne, Westbroek, Philippe, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Geraldo, Daniela A , Hakuzimana, Jean , Schwarz, Anne , Westbroek, Philippe , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263488 , vital:53632 , xlink:href="https://doi.org/10.1007/s10800-008-9716-y"
- Description: This paper reports on the use of thiol derivatised cobalt phthalocyanines as self assembled monolayers (SAMs) on gold disk electrode, gold ultramicro-cylinder electrode (UMCE) and on gold coated fiber for the detection of L-cysteine. The complexes are peripherally and non-peripherally substituted with phenylthio substituents. The SAM modified electrodes showed enhancement of catalytic currents and overpotential reduction occurred on the gold modified electrodes with different geometries. Electrocatalytic oxidation of L-cysteine on SAM modified gold coated fiber was reported for the first time. The gold coated fiber and ultramicro cylinder electrode were less stable towards the electrocatalytic oxidation of cysteine compared to its oxidation on the gold disk. The gold disk electrode gave better catalytic performance in terms of stability and reduction of overpotential.
- Full Text:
- Date Issued: 2009
- Authors: Nombona, Nolwazi , Geraldo, Daniela A , Hakuzimana, Jean , Schwarz, Anne , Westbroek, Philippe , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263488 , vital:53632 , xlink:href="https://doi.org/10.1007/s10800-008-9716-y"
- Description: This paper reports on the use of thiol derivatised cobalt phthalocyanines as self assembled monolayers (SAMs) on gold disk electrode, gold ultramicro-cylinder electrode (UMCE) and on gold coated fiber for the detection of L-cysteine. The complexes are peripherally and non-peripherally substituted with phenylthio substituents. The SAM modified electrodes showed enhancement of catalytic currents and overpotential reduction occurred on the gold modified electrodes with different geometries. Electrocatalytic oxidation of L-cysteine on SAM modified gold coated fiber was reported for the first time. The gold coated fiber and ultramicro cylinder electrode were less stable towards the electrocatalytic oxidation of cysteine compared to its oxidation on the gold disk. The gold disk electrode gave better catalytic performance in terms of stability and reduction of overpotential.
- Full Text:
- Date Issued: 2009