Wireless rotational process monitoring system
- Authors: Odendaal, Morné
- Date: 2011
- Subjects: Manufacturing processes -- Automation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9599 , http://hdl.handle.net/10948/1347 , Manufacturing processes -- Automation
- Description: The manufacturing industry is constantly looking for ways to reduce production costs and at the same time to increase productivity. Automation of common manufacturing operations is one of these methods. By automating common manufacturing operations; various machines, robots, control systems and information technologies are used to reduce the overall human input requirement (mental and physical). Recent advances in technology have made it possible to now also automate (or facilitate) the maintenance requirement of these machines and tools. Modern tools and machines, which can estimate when it will fail or when failure is imminent have obvious advantages for predictive maintenance purposes. Another function of this technology is to determine how efficiently a tool or machine operates, or what the quality of the produced goods is. Predictive maintenance can decrease manufacturing plant or machine down times – which have a positive effect on cost-savings – has gained considerable importance over the last two decades.
- Full Text:
- Date Issued: 2011
- Authors: Odendaal, Morné
- Date: 2011
- Subjects: Manufacturing processes -- Automation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9599 , http://hdl.handle.net/10948/1347 , Manufacturing processes -- Automation
- Description: The manufacturing industry is constantly looking for ways to reduce production costs and at the same time to increase productivity. Automation of common manufacturing operations is one of these methods. By automating common manufacturing operations; various machines, robots, control systems and information technologies are used to reduce the overall human input requirement (mental and physical). Recent advances in technology have made it possible to now also automate (or facilitate) the maintenance requirement of these machines and tools. Modern tools and machines, which can estimate when it will fail or when failure is imminent have obvious advantages for predictive maintenance purposes. Another function of this technology is to determine how efficiently a tool or machine operates, or what the quality of the produced goods is. Predictive maintenance can decrease manufacturing plant or machine down times – which have a positive effect on cost-savings – has gained considerable importance over the last two decades.
- Full Text:
- Date Issued: 2011
Women's empowerment in the post-1994 Rwanda: the case study of Mayaga Region
- Authors: Hategekimana, Celestin
- Date: 2011
- Subjects: Women in development -- Rwanda , Women -- Rwanda -- Social conditions , Women -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9068 , http://hdl.handle.net/10948/1314 , Women in development -- Rwanda , Women -- Rwanda -- Social conditions , Women -- Economic conditions
- Description: This research looks at the process of women’s empowerment in post- 1994 Rwanda, with special focus on twelve cooperatives working in Mayaga region and the way these cooperatives empower women, their households and the community at large. Traditional Rwandan society has been always bound by patriarchy which has not valued the reproductive roles of women as economically productive in their households and the society as a whole. On the one hand, this understanding was reversed in the post-1994 Rwanda by the commitment of the government to gender equality at the highest level of political leadership through progressive policies and legislation. On the other hand, in Mayaga region, cooperatives brought about socio-economic development and changed relationships of gender and power in a patriarchal post-conflict society. The findings from cooperatives in Mayaga region show that to prevent women from reaching their full potential is economic folly. If women are empowered, they can generate important development outcomes such as improved health, education, income levels and conflict resolution. The findings further indicate how women’s empowerment is determined by the livelihood strategies women adopt themselves to respond to their vulnerability, and by the ways in which they express their agency in making a living in a sustainable way, with the available community assets that they have access to (financial, social, human, natural and physical). This research highlights that the accessibility of the community assets used by women in Mayaga region and in Rwanda as a whole is also determined by policies, institutions and processes that are able to influence their livelihoods positively.
- Full Text:
- Date Issued: 2011
- Authors: Hategekimana, Celestin
- Date: 2011
- Subjects: Women in development -- Rwanda , Women -- Rwanda -- Social conditions , Women -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9068 , http://hdl.handle.net/10948/1314 , Women in development -- Rwanda , Women -- Rwanda -- Social conditions , Women -- Economic conditions
- Description: This research looks at the process of women’s empowerment in post- 1994 Rwanda, with special focus on twelve cooperatives working in Mayaga region and the way these cooperatives empower women, their households and the community at large. Traditional Rwandan society has been always bound by patriarchy which has not valued the reproductive roles of women as economically productive in their households and the society as a whole. On the one hand, this understanding was reversed in the post-1994 Rwanda by the commitment of the government to gender equality at the highest level of political leadership through progressive policies and legislation. On the other hand, in Mayaga region, cooperatives brought about socio-economic development and changed relationships of gender and power in a patriarchal post-conflict society. The findings from cooperatives in Mayaga region show that to prevent women from reaching their full potential is economic folly. If women are empowered, they can generate important development outcomes such as improved health, education, income levels and conflict resolution. The findings further indicate how women’s empowerment is determined by the livelihood strategies women adopt themselves to respond to their vulnerability, and by the ways in which they express their agency in making a living in a sustainable way, with the available community assets that they have access to (financial, social, human, natural and physical). This research highlights that the accessibility of the community assets used by women in Mayaga region and in Rwanda as a whole is also determined by policies, institutions and processes that are able to influence their livelihoods positively.
- Full Text:
- Date Issued: 2011
Work-family conflict, stress and some demographic and occupational variables among female factory workers in East London, South Africa
- Authors: Dywili, Mtutuzeli
- Date: 2011
- Subjects: Work and family -- South Africa , Job stress -- South Africa , Women employees -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24128 , vital:62382
- Description: The study examines work-family conflict, stress, and some demographic and occupational variables among female factory workers in East London, South Africa. The participants were female factory workers in East London, South Africa. The independent variables for the study were, demographic and occupational variables, while stress is the dependent variable. Work-family conflict is dependent on demographic and occupational variables, while on the other hand is independent to stress. The demographic variables concerned are age, marital status, number of children and age of the last born child. The occupational variable on the other hand is occupational level, i.e. managerial versus non-managerial. The measuring instruments were a self-designed questionnaire to measure the demographic and occupational variables, a questionnaire developed by Stephens and Sommer (1996) to measure work-family conflict (cronbach’s alpha = 0,90) and the Effort – Reward Imbalance (ERI) questionnaire (Pikhart, Bobak, Siegrist, Pajak, Rywick, Kyshegyi, Gostaus, Skodova& Marmot, 1996) to measure stress at workplace. Cronbach’s alpha for the whole questionnaire reaches the value of 0,89. , Thesis (MCom) -- Faculty of Management and Commerce, 2011
- Full Text:
- Date Issued: 2011
- Authors: Dywili, Mtutuzeli
- Date: 2011
- Subjects: Work and family -- South Africa , Job stress -- South Africa , Women employees -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24128 , vital:62382
- Description: The study examines work-family conflict, stress, and some demographic and occupational variables among female factory workers in East London, South Africa. The participants were female factory workers in East London, South Africa. The independent variables for the study were, demographic and occupational variables, while stress is the dependent variable. Work-family conflict is dependent on demographic and occupational variables, while on the other hand is independent to stress. The demographic variables concerned are age, marital status, number of children and age of the last born child. The occupational variable on the other hand is occupational level, i.e. managerial versus non-managerial. The measuring instruments were a self-designed questionnaire to measure the demographic and occupational variables, a questionnaire developed by Stephens and Sommer (1996) to measure work-family conflict (cronbach’s alpha = 0,90) and the Effort – Reward Imbalance (ERI) questionnaire (Pikhart, Bobak, Siegrist, Pajak, Rywick, Kyshegyi, Gostaus, Skodova& Marmot, 1996) to measure stress at workplace. Cronbach’s alpha for the whole questionnaire reaches the value of 0,89. , Thesis (MCom) -- Faculty of Management and Commerce, 2011
- Full Text:
- Date Issued: 2011
Would an asset-based community development approach counteract a community deficit mindset in Leliefontein?
- Authors: Hopkins, Grant Camden
- Date: 2011
- Subjects: Community development , Rural development , Sustainable development
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8691 , http://hdl.handle.net/10948/d1009316 , Community development , Rural development , Sustainable development
- Description: This research report aims to explore the potential of an Asset-Based Community Development (ABCD) approach in Leliefontein. Through the ABCD process, an inventory of the individual capacities of a sample group will be undertaken, as well as an inventory of the significant local associations, organisations and institutions, as well as their capacities. The objective will be to use the asset-mapping process to challenge negative community self-perceptions, enabling them to build new, positive images that empower and release latent potential. The information gathered will also be made available to the individuals, organisations, associations and institutions within the community, along with some ideas on how mutually beneficial partnerships can be developed. The key objective will be to assist the community of Leliefontein, to no longer regard themselves from a deficit mindset, but positively, as a community with tremendous resources, assets and relationships that can be harnessed for 4 community economic development. Asset-mapping can then be used by local organisations to build new relationships within the community, as well as relationships that harness resources outside of the immediate community.
- Full Text:
- Date Issued: 2011
- Authors: Hopkins, Grant Camden
- Date: 2011
- Subjects: Community development , Rural development , Sustainable development
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8691 , http://hdl.handle.net/10948/d1009316 , Community development , Rural development , Sustainable development
- Description: This research report aims to explore the potential of an Asset-Based Community Development (ABCD) approach in Leliefontein. Through the ABCD process, an inventory of the individual capacities of a sample group will be undertaken, as well as an inventory of the significant local associations, organisations and institutions, as well as their capacities. The objective will be to use the asset-mapping process to challenge negative community self-perceptions, enabling them to build new, positive images that empower and release latent potential. The information gathered will also be made available to the individuals, organisations, associations and institutions within the community, along with some ideas on how mutually beneficial partnerships can be developed. The key objective will be to assist the community of Leliefontein, to no longer regard themselves from a deficit mindset, but positively, as a community with tremendous resources, assets and relationships that can be harnessed for 4 community economic development. Asset-mapping can then be used by local organisations to build new relationships within the community, as well as relationships that harness resources outside of the immediate community.
- Full Text:
- Date Issued: 2011
Xenophobia and media: an exploratory study on the public perception of the Nelson Mandela Bay Community
- Authors: Mohamed, Osman Abdi
- Date: 2011
- Subjects: Xenophobia -- South Africa , Immigrants -- South Africa , Mass media -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9066 , http://hdl.handle.net/10948/1330 , Xenophobia -- South Africa , Immigrants -- South Africa , Mass media -- South Africa
- Description: Development in South Africa at present is at a crossroads; it could become injected with new energy or it could collapse. The presence of foreigners, especially those from Africa is in contention. Some argue that they help the economy whilst others argue they are a hindrance to locals and their employment worth. The “truth” regarding these may not be immediately recognisable and thus open to questioning depending on perception. The press plays a large role in these perceptions and has been criticised for the way it covers issues of public interest. it is envisaged that this study will be a useful contribution to the limited body of literature on xenophobia and media. The purpose of the study is to give foundation to the assumption that the media's constantly negative coverage of foreigner poses a very real threat to human rights as purported in South Africa‟s constitution, in addition to the economic significance, whether positive or not. This study highlights the perception that Nelson Mandela Bay residents have of foreign nationals, and whether negative reporting in the media has influenced residents' views of foreign nationals.
- Full Text:
- Date Issued: 2011
- Authors: Mohamed, Osman Abdi
- Date: 2011
- Subjects: Xenophobia -- South Africa , Immigrants -- South Africa , Mass media -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9066 , http://hdl.handle.net/10948/1330 , Xenophobia -- South Africa , Immigrants -- South Africa , Mass media -- South Africa
- Description: Development in South Africa at present is at a crossroads; it could become injected with new energy or it could collapse. The presence of foreigners, especially those from Africa is in contention. Some argue that they help the economy whilst others argue they are a hindrance to locals and their employment worth. The “truth” regarding these may not be immediately recognisable and thus open to questioning depending on perception. The press plays a large role in these perceptions and has been criticised for the way it covers issues of public interest. it is envisaged that this study will be a useful contribution to the limited body of literature on xenophobia and media. The purpose of the study is to give foundation to the assumption that the media's constantly negative coverage of foreigner poses a very real threat to human rights as purported in South Africa‟s constitution, in addition to the economic significance, whether positive or not. This study highlights the perception that Nelson Mandela Bay residents have of foreign nationals, and whether negative reporting in the media has influenced residents' views of foreign nationals.
- Full Text:
- Date Issued: 2011
Zimbabwe's Land Reform: myths and realities
- Authors: Helliker, Kirk D
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144710 , vital:38372 , DOI: 10.1080/02589001.2011.581502
- Description: Zimbabwe’s land reform is the first book on contemporary Zimbabwe that offers an empirically-rich and detailed account of redistributed farms that arose from ‘fasttrack’ land reform 10 years ago. In order to fully appreciate the significance of this book, it is necessary to outline briefly recent intellectual debates on Zimbabwe. Two main positions exist on Zimbabwean politics and society. The first position argues that the radical restructuring of agrarian relations (including undermining white agricultural capital and breaking up large commercial farms into smaller units) is a progressive tendency that has opened up opportunities for black small-scale farmers. Simultaneously, this position often underplays the existence of state restructuring of an authoritarian kind. The second position argues that land redistribution has dramatically undercut agricultural production thereby severely compromising food security for all Zimbabweans. It brings to the fore violent state action in instigating land occupations and in thwarting political opposition to ‘fast-track’.
- Full Text:
- Date Issued: 2011
- Authors: Helliker, Kirk D
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144710 , vital:38372 , DOI: 10.1080/02589001.2011.581502
- Description: Zimbabwe’s land reform is the first book on contemporary Zimbabwe that offers an empirically-rich and detailed account of redistributed farms that arose from ‘fasttrack’ land reform 10 years ago. In order to fully appreciate the significance of this book, it is necessary to outline briefly recent intellectual debates on Zimbabwe. Two main positions exist on Zimbabwean politics and society. The first position argues that the radical restructuring of agrarian relations (including undermining white agricultural capital and breaking up large commercial farms into smaller units) is a progressive tendency that has opened up opportunities for black small-scale farmers. Simultaneously, this position often underplays the existence of state restructuring of an authoritarian kind. The second position argues that land redistribution has dramatically undercut agricultural production thereby severely compromising food security for all Zimbabweans. It brings to the fore violent state action in instigating land occupations and in thwarting political opposition to ‘fast-track’.
- Full Text:
- Date Issued: 2011
‘Adolescence’, pregnancy and abortion: constructing a threat of degeneration
- Authors: Macleod, Catriona I
- Date: 2011
- Subjects: Adolescent Development Gender identity Gender studies
- Language: English
- Type: Book
- Identifier: vital:545 , http://hdl.handle.net/10962/d1014341 , https://www.tandfonline.com/doi/pdf/10.1080/13691058.2013.774523
- Description: Why, despite evidence to the contrary, does the narrative of the negative consequences of teenage pregnancy, abortion and childbearing persist? This book outlines a critical view of "teenage pregnancy" and abortion, arguing that the negativity surrounding early reproduction is underpinned by a particular understanding of adolescence. The book traces the invention of "adolescence" and the imaginary wall that the notion of "adolescence" constructs between young people and adults. It examines the entrenched status of "adolescence" within a colonialist discourse that equates development of the individual with the development of civilisation, and the consequent threat of degeneration that is implied in the very notion of "adolescence". Many important issues are explored, such as the ideologies and contradictions contained within the notion of "adolescence"; the invention of teenage pregnancy as a social problem; the construction of abortion as the new social problem; issues of race, culture and tradition in relation to teenage pregnancy; and health service provider practices, specifically in relation to managing risk. In the final chapter, an argument is made for a shift from the signifier "teenage pregnancy" to "unwanted pregnancy". Using data gathered from studies from four continents, this book highlights central issues in the global debate concerning teenage pregnancy. It is suitable for academics, postgraduate and undergraduate students of health psychology, women’s studies, nursing and sociology, as well as practitioners in the fields of youth and social work, medicine and counselling.
- Full Text: false
- Date Issued: 2011
- Authors: Macleod, Catriona I
- Date: 2011
- Subjects: Adolescent Development Gender identity Gender studies
- Language: English
- Type: Book
- Identifier: vital:545 , http://hdl.handle.net/10962/d1014341 , https://www.tandfonline.com/doi/pdf/10.1080/13691058.2013.774523
- Description: Why, despite evidence to the contrary, does the narrative of the negative consequences of teenage pregnancy, abortion and childbearing persist? This book outlines a critical view of "teenage pregnancy" and abortion, arguing that the negativity surrounding early reproduction is underpinned by a particular understanding of adolescence. The book traces the invention of "adolescence" and the imaginary wall that the notion of "adolescence" constructs between young people and adults. It examines the entrenched status of "adolescence" within a colonialist discourse that equates development of the individual with the development of civilisation, and the consequent threat of degeneration that is implied in the very notion of "adolescence". Many important issues are explored, such as the ideologies and contradictions contained within the notion of "adolescence"; the invention of teenage pregnancy as a social problem; the construction of abortion as the new social problem; issues of race, culture and tradition in relation to teenage pregnancy; and health service provider practices, specifically in relation to managing risk. In the final chapter, an argument is made for a shift from the signifier "teenage pregnancy" to "unwanted pregnancy". Using data gathered from studies from four continents, this book highlights central issues in the global debate concerning teenage pregnancy. It is suitable for academics, postgraduate and undergraduate students of health psychology, women’s studies, nursing and sociology, as well as practitioners in the fields of youth and social work, medicine and counselling.
- Full Text: false
- Date Issued: 2011
“Beautiful powerful you” : an analysis of the subject positions offered to women readers of Destiny magazine
- Authors: Jangara, Juliana
- Date: 2011
- Subjects: Destiny Magazine , Women's periodicals , Women, Black -- South Africa -- Social conditions , Sex role -- South Africa , Femininity -- South Africa , Women -- Identity , Feminism and mass media , Femininity (Philosophy)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3533 , http://hdl.handle.net/10962/d1013395
- Description: Women's magazines are popular cultural forms which offer readers representations intended to advise women on how to work towards and achieve idealised femininities. They perform such a function within the wider socio-historical context of gender relations. In a country such as South Africa, where patriarchal gender relations have historically been structured to favour men over women and masculinity over femininity, the representation of femininity in contemporary women's magazines may serve to reinforce or challenge these existent unequal gender relations. Informed by a feminist poststructuralist understanding of the gendered positioning of subjects through discourse, this study is a textual analysis that investigates the subject positions or possible identities offered to readers of Destiny, a South African business and lifestyle women's magazine. Black women, who make up the majority of Destiny's readership, have historically been excluded from the formal economy. In light of such a background, Destiny offers black women readers, through its representations of well-known business women, possible identities to take up within the white male dominated field of business practice. The magazine also offers 'lifestyle content', which suggests to readers possible ways of being in other areas of social life. Through a method of critical discourse analysis, this study critically analyses the subject positions offered to readers of Destiny, in order to determine to what extent the magazine's representations of business women endorse or confront unequal gender relations. The findings of this study are that Destiny offers women complex subject positions which simultaneously challenge and reassert patriarchy. While offering readers positions from which to challenge race based gender discrimination – a legacy of the apartheid past – the texts analysed tend to neglect non-racially motivated gender prejudice. It is concluded that although not comprehensively challenging unequal gender relations, the magazine whittles away some tenets of patriarchy.
- Full Text:
- Date Issued: 2011
- Authors: Jangara, Juliana
- Date: 2011
- Subjects: Destiny Magazine , Women's periodicals , Women, Black -- South Africa -- Social conditions , Sex role -- South Africa , Femininity -- South Africa , Women -- Identity , Feminism and mass media , Femininity (Philosophy)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3533 , http://hdl.handle.net/10962/d1013395
- Description: Women's magazines are popular cultural forms which offer readers representations intended to advise women on how to work towards and achieve idealised femininities. They perform such a function within the wider socio-historical context of gender relations. In a country such as South Africa, where patriarchal gender relations have historically been structured to favour men over women and masculinity over femininity, the representation of femininity in contemporary women's magazines may serve to reinforce or challenge these existent unequal gender relations. Informed by a feminist poststructuralist understanding of the gendered positioning of subjects through discourse, this study is a textual analysis that investigates the subject positions or possible identities offered to readers of Destiny, a South African business and lifestyle women's magazine. Black women, who make up the majority of Destiny's readership, have historically been excluded from the formal economy. In light of such a background, Destiny offers black women readers, through its representations of well-known business women, possible identities to take up within the white male dominated field of business practice. The magazine also offers 'lifestyle content', which suggests to readers possible ways of being in other areas of social life. Through a method of critical discourse analysis, this study critically analyses the subject positions offered to readers of Destiny, in order to determine to what extent the magazine's representations of business women endorse or confront unequal gender relations. The findings of this study are that Destiny offers women complex subject positions which simultaneously challenge and reassert patriarchy. While offering readers positions from which to challenge race based gender discrimination – a legacy of the apartheid past – the texts analysed tend to neglect non-racially motivated gender prejudice. It is concluded that although not comprehensively challenging unequal gender relations, the magazine whittles away some tenets of patriarchy.
- Full Text:
- Date Issued: 2011
Scoring an own goal? The Construction Workers 2010 World Cup Strike
- Authors: Cottle, Eddie
- Date: 2011-10-04
- Subjects: Labour disputes -- South Africa , Strikes and lockouts -- South Africa , Industrial relations -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60018 , vital:27722
- Description: The nationwide strike by 70 000 construction workers between 8 and 15 July 2009 was unprecedented and significant in several respects. This was the first national strike on 2010 World Cup sites by South African construction workers and was therefore an historic event. A second key feature of the strike was the unity displayed by workers and trade unions within a sector organised by several trade unions. Engineering and building workers came out on strike, with the Building Construction & Allied Workers Union (BCAWU) and the National Union of Mineworkers (NUM) standing together as their representative organisations. A third feature of the strike was the widespread sympathy for it by the South African public and media. This was despite it potentially setting back progress with World Cup projects. Fourthly, the pressure placed upon the trade unions' negotiating team by the Ministry of Labour and the FIFA Local Organising Committee (LOC) proved lethal in undermining their, assisting in causing them to dilute their trade union demands and demobilising the national strike.
- Full Text:
- Date Issued: 2011-10-04
- Authors: Cottle, Eddie
- Date: 2011-10-04
- Subjects: Labour disputes -- South Africa , Strikes and lockouts -- South Africa , Industrial relations -- South Africa
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60018 , vital:27722
- Description: The nationwide strike by 70 000 construction workers between 8 and 15 July 2009 was unprecedented and significant in several respects. This was the first national strike on 2010 World Cup sites by South African construction workers and was therefore an historic event. A second key feature of the strike was the unity displayed by workers and trade unions within a sector organised by several trade unions. Engineering and building workers came out on strike, with the Building Construction & Allied Workers Union (BCAWU) and the National Union of Mineworkers (NUM) standing together as their representative organisations. A third feature of the strike was the widespread sympathy for it by the South African public and media. This was despite it potentially setting back progress with World Cup projects. Fourthly, the pressure placed upon the trade unions' negotiating team by the Ministry of Labour and the FIFA Local Organising Committee (LOC) proved lethal in undermining their, assisting in causing them to dilute their trade union demands and demobilising the national strike.
- Full Text:
- Date Issued: 2011-10-04
Detecting impacts of invasive non-native sharptooth catfish, Clarias gariepinus, within invaded and non-invaded rivers.
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124100 , vital:35539 , https://doi.10.1007/s10531-012-0291-5
- Description: In aquatic ecosystems, impacts by invasive introduced fish can be likened to press disturbances that persistently influence communities. This study examined invasion disturbances by determining the relationship between non-native sharptooth catfish Clarias gariepinus and aquatic macroinvertebrates in the Eastern Cape, South Africa. A Multiple Before–After Control–Impact (MBACI) experimental design was used to examine macroinvertebrate communities within two rivers: one with catfish and another one without catfish. Within the invaded river, macroinvertebrates showed little response to catfish presence, whereas predator exclusion appeared to benefit community structure. This suggests that the macroinvertebrate community within the invaded river was adapted to predation impact because of the dominance of resilient taxa, such as Hirudinea, Oligochaeta and Chironomidae that were abundant in the Impact treatment relative to the Control treatment. High macroinvertebrate diversity and richness that was observed in the Control treatment, which excluded the predator, relative to the Impact treatment suggests predator avoidance behaviour within the invaded river. By comparison, within the uninvaded river, catfish introduction into the Impact treatment plots indicated negative effects on macroinvertebrate community that was reflected by decrease in diversity, richness and biomass. A community level impact was also reflected in the multivariate analysis that indicated more variation in macroinvertebrate composition within the Impact treatment relative to the Control in the uninvaded river. Catfish impact within the uninvaded river suggests the dominance of vulnerable taxa, such as odonates that were less abundant in the Impact treatment plots after catfish introduction. From a disturbance perspective, this study revealed different macroinvertebrate responses to catfish impact, and suggests that within invaded habitats, macroinvertebrates were less responsive to catfish presence, whereas catfish introduction within uninvaded habitats demonstrated invasion impact that was shown by a decrease in the abundance of vulnerable taxa. The occurrence of non-native sharptooth catfish within many Eastern Cape rivers is a concern because of its predation impact and potential to influence trophic interrelationships, and efforts should be taken to protect uninvaded rivers, and, where possible, eradicate the invader.
- Full Text:
- Date Issued: 2012
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124100 , vital:35539 , https://doi.10.1007/s10531-012-0291-5
- Description: In aquatic ecosystems, impacts by invasive introduced fish can be likened to press disturbances that persistently influence communities. This study examined invasion disturbances by determining the relationship between non-native sharptooth catfish Clarias gariepinus and aquatic macroinvertebrates in the Eastern Cape, South Africa. A Multiple Before–After Control–Impact (MBACI) experimental design was used to examine macroinvertebrate communities within two rivers: one with catfish and another one without catfish. Within the invaded river, macroinvertebrates showed little response to catfish presence, whereas predator exclusion appeared to benefit community structure. This suggests that the macroinvertebrate community within the invaded river was adapted to predation impact because of the dominance of resilient taxa, such as Hirudinea, Oligochaeta and Chironomidae that were abundant in the Impact treatment relative to the Control treatment. High macroinvertebrate diversity and richness that was observed in the Control treatment, which excluded the predator, relative to the Impact treatment suggests predator avoidance behaviour within the invaded river. By comparison, within the uninvaded river, catfish introduction into the Impact treatment plots indicated negative effects on macroinvertebrate community that was reflected by decrease in diversity, richness and biomass. A community level impact was also reflected in the multivariate analysis that indicated more variation in macroinvertebrate composition within the Impact treatment relative to the Control in the uninvaded river. Catfish impact within the uninvaded river suggests the dominance of vulnerable taxa, such as odonates that were less abundant in the Impact treatment plots after catfish introduction. From a disturbance perspective, this study revealed different macroinvertebrate responses to catfish impact, and suggests that within invaded habitats, macroinvertebrates were less responsive to catfish presence, whereas catfish introduction within uninvaded habitats demonstrated invasion impact that was shown by a decrease in the abundance of vulnerable taxa. The occurrence of non-native sharptooth catfish within many Eastern Cape rivers is a concern because of its predation impact and potential to influence trophic interrelationships, and efforts should be taken to protect uninvaded rivers, and, where possible, eradicate the invader.
- Full Text:
- Date Issued: 2012
Inter-seasonal persistence and size-structuring of two minnow species within headwater streams in the Eastern Cape, South Africa
- Kadye, Wilbert T, Booth, Anthony J
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124866 , vital:35705 , https://doi.10.1111/j.1439-0426.2012.02027.x
- Description: This study examined temporal variation in population dynamics and size structuring of two cyprinid minnows, Pseudobarbus afer and Barbus anoplus, in relation to their proximate physical habitats. Population estimates were determined using three-pass depletion sampling during both summer and winter. The habitats were characterised by seasonal variation in all physico-chemical conditions and spatial variation in substrata compositions. Whereas significant differences in population size were noted between seasons for B. anoplus, no differences were found between seasons for density and capture probability for either species. An increase in boulders was associated with increase in population size and density for P. afer; for B. anoplus, increased percentages of bedrock and bank vegetation were associated with an increase in population size and probability of capture, respectively. According to Canonical Correspondence Analysis, size structuring in P. afer was explained predominantly by seasonality, with smaller length classes associated with the seasonal variable of summer, while larger length classes were associated with pH that was higher in winter. By comparison, for B. anoplus, the habitat variables – bank vegetation and bedrock – accounted for much of the explained variance for size structuring. Recruitment appeared to be the major driver of size structuring for the two species; refugia, especially boulders and bank vegetation, also appeared to be important. Overall, the two species were adapted to the headwater streams that were generally variable in environmental conditions. Potential invasions by non-native invasive fishes that occur within the mainstream habitats threaten these two species. Efforts should continue to protect these minnows from such invasions by constructing barriers to upstream migration of non-native fishes into these headwater habitats.
- Full Text:
- Date Issued: 2012
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124866 , vital:35705 , https://doi.10.1111/j.1439-0426.2012.02027.x
- Description: This study examined temporal variation in population dynamics and size structuring of two cyprinid minnows, Pseudobarbus afer and Barbus anoplus, in relation to their proximate physical habitats. Population estimates were determined using three-pass depletion sampling during both summer and winter. The habitats were characterised by seasonal variation in all physico-chemical conditions and spatial variation in substrata compositions. Whereas significant differences in population size were noted between seasons for B. anoplus, no differences were found between seasons for density and capture probability for either species. An increase in boulders was associated with increase in population size and density for P. afer; for B. anoplus, increased percentages of bedrock and bank vegetation were associated with an increase in population size and probability of capture, respectively. According to Canonical Correspondence Analysis, size structuring in P. afer was explained predominantly by seasonality, with smaller length classes associated with the seasonal variable of summer, while larger length classes were associated with pH that was higher in winter. By comparison, for B. anoplus, the habitat variables – bank vegetation and bedrock – accounted for much of the explained variance for size structuring. Recruitment appeared to be the major driver of size structuring for the two species; refugia, especially boulders and bank vegetation, also appeared to be important. Overall, the two species were adapted to the headwater streams that were generally variable in environmental conditions. Potential invasions by non-native invasive fishes that occur within the mainstream habitats threaten these two species. Efforts should continue to protect these minnows from such invasions by constructing barriers to upstream migration of non-native fishes into these headwater habitats.
- Full Text:
- Date Issued: 2012
The nature and quality of the mathematical connections teachers make:
- Mhlolo, Michael K, Schäfer, Marc, Venkat, Hamsa
- Authors: Mhlolo, Michael K , Schäfer, Marc , Venkat, Hamsa
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140893 , vital:37927 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC120887
- Description: Current reforms in mathematics education emphasise the need for pedagogy because it offers learners opportunities to develop their proficiency with complex high-level cognitive processes. One has always associated the ability to make mathematical connections, together with the teacher's role in teaching them, with deep mathematical understanding. This article examines the nature and quality of the mathematical connections that the teachers' representations of those connections enabled or constrained. The researchers made video recordings of four Grade 11 teachers as they taught a series of five lessons on algebra-related topics. The results showed that the teachers' representations of mathematical connections were either faulty or superficial in most cases. It compromised the learners' opportunities for making meaningful mathematical connections. The researchers concluded by suggesting that helping teachers to build their representation repertoires could increase the effectiveness of their instructional practices.
- Full Text:
- Date Issued: 2012
- Authors: Mhlolo, Michael K , Schäfer, Marc , Venkat, Hamsa
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140893 , vital:37927 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC120887
- Description: Current reforms in mathematics education emphasise the need for pedagogy because it offers learners opportunities to develop their proficiency with complex high-level cognitive processes. One has always associated the ability to make mathematical connections, together with the teacher's role in teaching them, with deep mathematical understanding. This article examines the nature and quality of the mathematical connections that the teachers' representations of those connections enabled or constrained. The researchers made video recordings of four Grade 11 teachers as they taught a series of five lessons on algebra-related topics. The results showed that the teachers' representations of mathematical connections were either faulty or superficial in most cases. It compromised the learners' opportunities for making meaningful mathematical connections. The researchers concluded by suggesting that helping teachers to build their representation repertoires could increase the effectiveness of their instructional practices.
- Full Text:
- Date Issued: 2012
The nature of geometry instruction and observed learning-outcomes opportunities in Nigerian and South African high schools:
- Atebe, Humphrey U, Schäfer, Marc
- Authors: Atebe, Humphrey U , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140919 , vital:37929 , DOI: 10.1080/10288457.2011.10740712
- Description: The purpose of this qualitative case study involving six secondary school teachers was to obtain insight into how geometry is taught in selected Nigerian and South African high schools. It also aimed, by making use of the van Hiele model of geometry instruction, to elucidate what possible learning opportunities observed instructional methods could offer learners in the subject. The sample comprised three mathematics teachers from Nigeria and three mathematics teachers from South Africa, all of whom were selected using purposive sampling techniques. Instructional activities in six geometry classrooms were recorded on videotape. The van Hiele learning phases provided the framework for data analysis. The findings of this study indicate that observed teaching methods in geometry classrooms in the participating schools offer learners scant opportunity to learn geometry.
- Full Text:
- Date Issued: 2013
- Authors: Atebe, Humphrey U , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140919 , vital:37929 , DOI: 10.1080/10288457.2011.10740712
- Description: The purpose of this qualitative case study involving six secondary school teachers was to obtain insight into how geometry is taught in selected Nigerian and South African high schools. It also aimed, by making use of the van Hiele model of geometry instruction, to elucidate what possible learning opportunities observed instructional methods could offer learners in the subject. The sample comprised three mathematics teachers from Nigeria and three mathematics teachers from South Africa, all of whom were selected using purposive sampling techniques. Instructional activities in six geometry classrooms were recorded on videotape. The van Hiele learning phases provided the framework for data analysis. The findings of this study indicate that observed teaching methods in geometry classrooms in the participating schools offer learners scant opportunity to learn geometry.
- Full Text:
- Date Issued: 2013
Synthesis and evaluation of novel inhibitors of 1-Deoxy-D-xylolose-5-phosphate reductoisomerase as potential antimalarials
- Authors: Conibear, Anne Claire
- Date: 2013-07-19
- Subjects: Antimalarials -- Development , Malaria -- Chemotherapy , Drug development , Enzyme kinetics , Phosphate esters
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4451 , http://hdl.handle.net/10962/d1008282 , Antimalarials -- Development , Malaria -- Chemotherapy , Drug development , Enzyme kinetics , Phosphate esters
- Description: Malaria continues to be an enormous health-threat in the developing world and the emergence of drug resistance has further compounded the problem. The parasite-specific enzyme, 1-deoxY-D-xylulose-S-phosphate reductoisomerase (DXR), has recently been validated as a promising antimalarial drug target. The present study comprises a combination of synthetic, physical organic, computer modelling and bioassay techniques directed towards the development of novel DXR inhibitors. A range of 2-heteroarylamino-2-oxoethyl- and 2- heteroarylamino-2-oxopropyl phosphonate esters and their corresponding phosphonic acid salts have been synthesised as analogues of the highly active DXR inhibitor, fosmidomycin. Treatment of the heteroarylamino precursors with chloroacetyl chloride or chloropropionyl chloride afforded chloroamide intermediates, Arbuzov reactions of which led to the corresponding diethyl phosphonate esters. Hydrolysis of the esters has been effected using bromotrimethylsilane. Twenty-four new compounds have been prepared and fully characterised using elemental (HRMS or combustion) and spectroscopic (1- and 2-D NMR and IR) analysis. A 31p NMR kinetic study has been carried out on the two-step silylation reaction involved in the hydrolysis of the phosphonate esters and has provided activation parameters for the reaction. The kinetic analysis was refined using a computational method to give an improved fit with the experimental data. Saturation transfer difference (STD) NMR analysis, computer-simulated docking and enzyme inhibition assays have been used to evaluate the enzyme-binding and -inhibition potential of the synthesised ligands. Minimal to moderate inhibitory activity has been observed and several structure-activity relationships have been identified. In silica exploration of the DXR active site has revealed an additional binding pocket and information on the topology of the active site has led to the de novo design of a new series of potential ligands. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Conibear, Anne Claire
- Date: 2013-07-19
- Subjects: Antimalarials -- Development , Malaria -- Chemotherapy , Drug development , Enzyme kinetics , Phosphate esters
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4451 , http://hdl.handle.net/10962/d1008282 , Antimalarials -- Development , Malaria -- Chemotherapy , Drug development , Enzyme kinetics , Phosphate esters
- Description: Malaria continues to be an enormous health-threat in the developing world and the emergence of drug resistance has further compounded the problem. The parasite-specific enzyme, 1-deoxY-D-xylulose-S-phosphate reductoisomerase (DXR), has recently been validated as a promising antimalarial drug target. The present study comprises a combination of synthetic, physical organic, computer modelling and bioassay techniques directed towards the development of novel DXR inhibitors. A range of 2-heteroarylamino-2-oxoethyl- and 2- heteroarylamino-2-oxopropyl phosphonate esters and their corresponding phosphonic acid salts have been synthesised as analogues of the highly active DXR inhibitor, fosmidomycin. Treatment of the heteroarylamino precursors with chloroacetyl chloride or chloropropionyl chloride afforded chloroamide intermediates, Arbuzov reactions of which led to the corresponding diethyl phosphonate esters. Hydrolysis of the esters has been effected using bromotrimethylsilane. Twenty-four new compounds have been prepared and fully characterised using elemental (HRMS or combustion) and spectroscopic (1- and 2-D NMR and IR) analysis. A 31p NMR kinetic study has been carried out on the two-step silylation reaction involved in the hydrolysis of the phosphonate esters and has provided activation parameters for the reaction. The kinetic analysis was refined using a computational method to give an improved fit with the experimental data. Saturation transfer difference (STD) NMR analysis, computer-simulated docking and enzyme inhibition assays have been used to evaluate the enzyme-binding and -inhibition potential of the synthesised ligands. Minimal to moderate inhibitory activity has been observed and several structure-activity relationships have been identified. In silica exploration of the DXR active site has revealed an additional binding pocket and information on the topology of the active site has led to the de novo design of a new series of potential ligands. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
A framework for successful SOA adoption in selected South African universities
- Authors: Jacobs, Carmen
- Date: 2013-07-26
- Subjects: System analysis -- Data processing , System design -- Data processing , Systems integration , Service-oriented architecture (Computer science) , Education, Higher -- Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1153 , http://hdl.handle.net/10962/d1008366 , System analysis -- Data processing , System design -- Data processing , Systems integration , Service-oriented architecture (Computer science) , Education, Higher -- Data processing
- Description: The demand for systems i·ntegration has become more and more significant in higher education as institutions want systems that provide coherent information with data that is up to date and not redundant and can seamlessly support the end user experience. Institutions have become more reliant on information systems to support both administrative functions and those involved in teaching, learning and research, but because each department supports a diverse array of computing platforms and applications, it becomes very difficult to integrate these systems. SOA is classified as an innovative approach to integrating existing systems involving the use of independent services that can be accessed without knowledge of the underlying platform implementation. Unfortunately, the SOA initiative will not be success if it is not understood and used correctly by various applications and systems throughout the organisation. SOA introduces complexity and challenges in systems integration, acceptance, governance, data, development planning, security and external opportunities. If an organisation does not embrace or enable change in each of these areas, it is not ready for the adoption of SOA. This research investigates the systems integration challenge in selected South African universities and explores factors for SOA adoption. The framework for the adoption of SOA comprises seven factors, of which Systems Integration is the most significant and represents an efficient starting point for institutions considering SOA adoption. Acceptance, Governance, Data, Development Planning, Security and External Opportunities are other factors of SOA adoption that require careful and thorough consideration before an institution can successfully adopt SOA. The results of this research emphasise the importance of being able to embrace change and innovation and modify strategies in order to reflect the constant changes required for the adoption of SOA. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Jacobs, Carmen
- Date: 2013-07-26
- Subjects: System analysis -- Data processing , System design -- Data processing , Systems integration , Service-oriented architecture (Computer science) , Education, Higher -- Data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1153 , http://hdl.handle.net/10962/d1008366 , System analysis -- Data processing , System design -- Data processing , Systems integration , Service-oriented architecture (Computer science) , Education, Higher -- Data processing
- Description: The demand for systems i·ntegration has become more and more significant in higher education as institutions want systems that provide coherent information with data that is up to date and not redundant and can seamlessly support the end user experience. Institutions have become more reliant on information systems to support both administrative functions and those involved in teaching, learning and research, but because each department supports a diverse array of computing platforms and applications, it becomes very difficult to integrate these systems. SOA is classified as an innovative approach to integrating existing systems involving the use of independent services that can be accessed without knowledge of the underlying platform implementation. Unfortunately, the SOA initiative will not be success if it is not understood and used correctly by various applications and systems throughout the organisation. SOA introduces complexity and challenges in systems integration, acceptance, governance, data, development planning, security and external opportunities. If an organisation does not embrace or enable change in each of these areas, it is not ready for the adoption of SOA. This research investigates the systems integration challenge in selected South African universities and explores factors for SOA adoption. The framework for the adoption of SOA comprises seven factors, of which Systems Integration is the most significant and represents an efficient starting point for institutions considering SOA adoption. Acceptance, Governance, Data, Development Planning, Security and External Opportunities are other factors of SOA adoption that require careful and thorough consideration before an institution can successfully adopt SOA. The results of this research emphasise the importance of being able to embrace change and innovation and modify strategies in order to reflect the constant changes required for the adoption of SOA. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
An organisation development intervention in an Anglican church theological seminary in Southern Africa
- Authors: Chinganga, Percy
- Date: 2013-08-08
- Subjects: College of the Transfiguration (Grahamstown, South Africa) Organizational change -- Church of England -- Africa, Southern Leadership -- Religious aspects -- Christianity -- Africa, Southern Church management -- Church of England -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1959 , http://hdl.handle.net/10962/d1008377
- Description: "Organisation development is a planned, systematic process in which applied behavioral science principles and practices are introduced into ongoing organisations toward the goal of increasing individual and organisational effectiveness. " [French and Bell] This study describes and analyses the implementation of Organisation Development (OD) to an Anglican Church theological seminary, The College of the Transfiguration (Cott), in the Anglican Church of the Province of Southern Africa (ACSA). The origins of OD are business related, emerging in the late 1950s and early 1960s. Over the years, and recently in South Africa, OD has been applied in educational change initiatives. Unlike more traditional change strategies, OD promotes collaboration in organisational change processes through the inclusive participation of all stakeholders. This study is unique in the sense that OD is applied to an Anglican Church theological institution in Southern Africa. The goal of theological institutions, particularly Cot!, is to "form, inform and transform" (Cot! Prospectus, 2011) those who feel called to ordained ministry. Personal experience in this practice has confirmed that organisational emphasis is placed more on product than process; on results rather than the leadership and management of the organisation. This study was an attempt to introduce a process of planned change to such an organisational context. OD was introduced to The College of the Transfiguration in the form of action research using the Survey Data Feedback (SDF) strategy. Data gathered was interpreted and analysed, followed by action planning and implementation of agreed plans. The process had a positive impact on both stakeholders and the organisation despite the challenges associated with the unpredictable world of organisations. Ultimately, I propose tentative recommendations which could help Cott and other educational institutions to achieve long-term improvement in organisational leadership and management.
- Full Text:
- Authors: Chinganga, Percy
- Date: 2013-08-08
- Subjects: College of the Transfiguration (Grahamstown, South Africa) Organizational change -- Church of England -- Africa, Southern Leadership -- Religious aspects -- Christianity -- Africa, Southern Church management -- Church of England -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1959 , http://hdl.handle.net/10962/d1008377
- Description: "Organisation development is a planned, systematic process in which applied behavioral science principles and practices are introduced into ongoing organisations toward the goal of increasing individual and organisational effectiveness. " [French and Bell] This study describes and analyses the implementation of Organisation Development (OD) to an Anglican Church theological seminary, The College of the Transfiguration (Cott), in the Anglican Church of the Province of Southern Africa (ACSA). The origins of OD are business related, emerging in the late 1950s and early 1960s. Over the years, and recently in South Africa, OD has been applied in educational change initiatives. Unlike more traditional change strategies, OD promotes collaboration in organisational change processes through the inclusive participation of all stakeholders. This study is unique in the sense that OD is applied to an Anglican Church theological institution in Southern Africa. The goal of theological institutions, particularly Cot!, is to "form, inform and transform" (Cot! Prospectus, 2011) those who feel called to ordained ministry. Personal experience in this practice has confirmed that organisational emphasis is placed more on product than process; on results rather than the leadership and management of the organisation. This study was an attempt to introduce a process of planned change to such an organisational context. OD was introduced to The College of the Transfiguration in the form of action research using the Survey Data Feedback (SDF) strategy. Data gathered was interpreted and analysed, followed by action planning and implementation of agreed plans. The process had a positive impact on both stakeholders and the organisation despite the challenges associated with the unpredictable world of organisations. Ultimately, I propose tentative recommendations which could help Cott and other educational institutions to achieve long-term improvement in organisational leadership and management.
- Full Text:
The effect of sewage effluent from De Beers marine diamond mining operations on the expression of cytochrome P450 (CYP1A) and vitellogenin (vtg)
- Authors: De Almeida, Louise
- Date: 2013-09-20
- Subjects: De Beers Consolidated Mines , Sewage disposal in rivers, lakes, etc. -- Namibia , Endocrine disrupting chemicals in water -- Namibia , Merluccius capensis -- Namibia , Merluccius -- Namibia , Water -- Pollution -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4096 , http://hdl.handle.net/10962/d1009440 , De Beers Consolidated Mines , Sewage disposal in rivers, lakes, etc. -- Namibia , Endocrine disrupting chemicals in water -- Namibia , Merluccius capensis -- Namibia , Merluccius -- Namibia , Water -- Pollution -- Namibia
- Description: Sewage effluents disposed into the marine environment from De Beers Marine Namibia diamond mining vessels have the potential to cause endocrine disruptive effects in marine organisms. Endocrine disruption refers to the alteration of the normal functioning of the endocrine system and various chemicals have the ability to mimic hormones, effecting endogenous hormone synthesis, transport, receptor interaction and intracellular signaling. The potential endocrine disruptive effects, caused by the release of different types of sewage effluents into the ocean, on fish species is a concern due to the commercial importance of fish species found in the mining area e.g. hake, sole, horse mackerel. Increased awareness of marine environmental degradation due to the presence of chemical contaminants has resulted in research being done on early warning systems, in the form of biomarkers. Cytochrome P450 monooxygenase 1A (CYP1A) and vitellogenin (vtg) are important proteins found in fish liver and blood, that have been used as biomarkers for the detection of pollutants in fish. CYP1A is a subfamily of the P450 superfamily of enzymes and catalyzes the oxidation, hydrolysis and reduction of exogenous and endogenous compounds (phase I reactions) and thus has the capacity to regulate the metabolism of several organic contaminants. CYP1A expression is altered by exposure to planar xenobiotic compounds e.g. polyaromatic hydrocarbons. Vtg is an important precursor for egg yolk proteins and plays a role in the growth and development of an oocyte. Expression of this protein is altered upon exposure to estrogenic compounds. The aim of this project was to isolate CYP1A from fish liver by differential centrifugation and optimize conditions for the CYP1A-mediated ethoxyresorufin-Odeethylase (EROD) assay and western blot analysis (to assess CYP1A expression). Another aim of this study was to evaluate the potential effects of biologically disruptive chemicals from sewage effluents, discharged into the marine environment, on the expression of CYP1A in two species of hake, Merluccius capensis and M. paradoxus (Cape hake). CYP1A in Cape hake is approximately a 60 kDa protein and the highest EROD activity was detected in the microsomal fraction after differential centrifugation. Optimal EROD assay conditions were observed at pH 7.5, a temperature of 25 °C, 10 μl of sample and a reaction time of 30 seconds. Enzyme stability assays indicated a drastic decrease in enzyme activity after 30 seconds. The EROD assay was not NADPH dependent but was limited by NADPH supply, with an increase of 300% in EROD activity being observed with the addition of 0.1 M exogenous NADPH. The addition of dicumarol (40 μM), a phase II enzyme inhibitor, showed a 232% increase in EROD activity. This is because dicumarol inhibited enzymes with the capacity to metabolize the product (resorufin) of the EROD reaction. With regard to western blot analysis, the optimal primary (rabbit antifish CYP1A peptide) and secondary (anti-mouse/rabbit antibody-horseradish peroxidase conjugate (POD)) antibody dilutions were determined to be 1:1000 and 1:5000, respectively. The comparison of CYP1A expression in Cape hake samples from De Beers Marine mining area and reference sites showed higher EROD activity (16.29 ± 0.91 pmol/min) in fish samples from the mining area in comparison to the reference site (10.42 ± 2.65 pmol/min). Western blot analysis was in agreement with the EROD assay results and a higher CYP1A expression was observed in fish from the mining sites. The increased CYP1A expression observed in fish from the mining area is not definitively an indication of a pollutant effect in the environment, as several environmental and biological factors (e.g. photoperiod and age) must also be considered before reaching this conclusion. Another aim of this study was to purify vtg from Cape hake blood samples. Cape hake vtg was purified from fish plasma by selective precipitation with MgCl2 and EDTA. Precipitated sample was subjected to anion exchange chromatography using fast protein liquid chromatography (FPLC). Vtg eluted as two broad peaks and had a molecular weight above 200 kDa. SDS-PAGE analysis also resolved smaller molecular weight proteins below 70 kDa, which were thought to be vitellogenin cleavage proteins, lipovitellin and phosphovitins. Western blot analysis was performed; however, it did not produce any conclusive results. The purification of vtg enables further studies in characterizing this protein and developing assay aimed at detecting estrogenic pollutants in the marine environment
- Full Text:
- Authors: De Almeida, Louise
- Date: 2013-09-20
- Subjects: De Beers Consolidated Mines , Sewage disposal in rivers, lakes, etc. -- Namibia , Endocrine disrupting chemicals in water -- Namibia , Merluccius capensis -- Namibia , Merluccius -- Namibia , Water -- Pollution -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4096 , http://hdl.handle.net/10962/d1009440 , De Beers Consolidated Mines , Sewage disposal in rivers, lakes, etc. -- Namibia , Endocrine disrupting chemicals in water -- Namibia , Merluccius capensis -- Namibia , Merluccius -- Namibia , Water -- Pollution -- Namibia
- Description: Sewage effluents disposed into the marine environment from De Beers Marine Namibia diamond mining vessels have the potential to cause endocrine disruptive effects in marine organisms. Endocrine disruption refers to the alteration of the normal functioning of the endocrine system and various chemicals have the ability to mimic hormones, effecting endogenous hormone synthesis, transport, receptor interaction and intracellular signaling. The potential endocrine disruptive effects, caused by the release of different types of sewage effluents into the ocean, on fish species is a concern due to the commercial importance of fish species found in the mining area e.g. hake, sole, horse mackerel. Increased awareness of marine environmental degradation due to the presence of chemical contaminants has resulted in research being done on early warning systems, in the form of biomarkers. Cytochrome P450 monooxygenase 1A (CYP1A) and vitellogenin (vtg) are important proteins found in fish liver and blood, that have been used as biomarkers for the detection of pollutants in fish. CYP1A is a subfamily of the P450 superfamily of enzymes and catalyzes the oxidation, hydrolysis and reduction of exogenous and endogenous compounds (phase I reactions) and thus has the capacity to regulate the metabolism of several organic contaminants. CYP1A expression is altered by exposure to planar xenobiotic compounds e.g. polyaromatic hydrocarbons. Vtg is an important precursor for egg yolk proteins and plays a role in the growth and development of an oocyte. Expression of this protein is altered upon exposure to estrogenic compounds. The aim of this project was to isolate CYP1A from fish liver by differential centrifugation and optimize conditions for the CYP1A-mediated ethoxyresorufin-Odeethylase (EROD) assay and western blot analysis (to assess CYP1A expression). Another aim of this study was to evaluate the potential effects of biologically disruptive chemicals from sewage effluents, discharged into the marine environment, on the expression of CYP1A in two species of hake, Merluccius capensis and M. paradoxus (Cape hake). CYP1A in Cape hake is approximately a 60 kDa protein and the highest EROD activity was detected in the microsomal fraction after differential centrifugation. Optimal EROD assay conditions were observed at pH 7.5, a temperature of 25 °C, 10 μl of sample and a reaction time of 30 seconds. Enzyme stability assays indicated a drastic decrease in enzyme activity after 30 seconds. The EROD assay was not NADPH dependent but was limited by NADPH supply, with an increase of 300% in EROD activity being observed with the addition of 0.1 M exogenous NADPH. The addition of dicumarol (40 μM), a phase II enzyme inhibitor, showed a 232% increase in EROD activity. This is because dicumarol inhibited enzymes with the capacity to metabolize the product (resorufin) of the EROD reaction. With regard to western blot analysis, the optimal primary (rabbit antifish CYP1A peptide) and secondary (anti-mouse/rabbit antibody-horseradish peroxidase conjugate (POD)) antibody dilutions were determined to be 1:1000 and 1:5000, respectively. The comparison of CYP1A expression in Cape hake samples from De Beers Marine mining area and reference sites showed higher EROD activity (16.29 ± 0.91 pmol/min) in fish samples from the mining area in comparison to the reference site (10.42 ± 2.65 pmol/min). Western blot analysis was in agreement with the EROD assay results and a higher CYP1A expression was observed in fish from the mining sites. The increased CYP1A expression observed in fish from the mining area is not definitively an indication of a pollutant effect in the environment, as several environmental and biological factors (e.g. photoperiod and age) must also be considered before reaching this conclusion. Another aim of this study was to purify vtg from Cape hake blood samples. Cape hake vtg was purified from fish plasma by selective precipitation with MgCl2 and EDTA. Precipitated sample was subjected to anion exchange chromatography using fast protein liquid chromatography (FPLC). Vtg eluted as two broad peaks and had a molecular weight above 200 kDa. SDS-PAGE analysis also resolved smaller molecular weight proteins below 70 kDa, which were thought to be vitellogenin cleavage proteins, lipovitellin and phosphovitins. Western blot analysis was performed; however, it did not produce any conclusive results. The purification of vtg enables further studies in characterizing this protein and developing assay aimed at detecting estrogenic pollutants in the marine environment
- Full Text:
Between a cushion and a risky conversation: ARTS LOUNGE reviewed
- Authors: Baasch, Rachel M
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147703 , vital:38662 , https://doi.org/10.1080/00043389.2011.11877155
- Description: On the fringe of the National Arts Festival, at a point of transition between Rhodes University campus and the commercial side of Grahamstown, the walls of a former home and former horse-stable, now a research house, reverberate with the strain of cross-disciplinary, site-specific collaboration. The ARTS LOUNGE made its first official appearance at the Grahamstown National Arts Festival (ViPPA Research Center, Rhodes University) from 30 June to 9 July 2011. The ten-day event was organised by the Visual and Performing Arts of Africa Research (ViPPA) team in collaboration with musicians, artists, writers, performers and members of the public.
- Full Text:
- Date Issued: 2017
- Authors: Baasch, Rachel M
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147703 , vital:38662 , https://doi.org/10.1080/00043389.2011.11877155
- Description: On the fringe of the National Arts Festival, at a point of transition between Rhodes University campus and the commercial side of Grahamstown, the walls of a former home and former horse-stable, now a research house, reverberate with the strain of cross-disciplinary, site-specific collaboration. The ARTS LOUNGE made its first official appearance at the Grahamstown National Arts Festival (ViPPA Research Center, Rhodes University) from 30 June to 9 July 2011. The ten-day event was organised by the Visual and Performing Arts of Africa Research (ViPPA) team in collaboration with musicians, artists, writers, performers and members of the public.
- Full Text:
- Date Issued: 2017
Bollywood Nights: Indian youth and the creation of diasporic identity in South Africa
- Authors: Boshoff, Priscilla A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143494 , vital:38251 , DOI: 10.3138/topia.26.29
- Description: Bollywood’s popularity as a global cultural form has occurred at the same time as the valorization of difference in the South African political landscape. As the youngest members of the 19th-century labour diaspora, South African Indian youths are the inheritors of a conservative—yet adaptable—home culture amidst the marginalized identities of (post-)apartheid South Africa. Their desire to create an identity for themselves that encompasses their self-perception both as modern South African subjects and as guardians of their traditional home cultures is achieved through Bollywood, which speaks to its diasporic audiences through images of an idealized traditional yet modern India. While India is not a place of return for these youth, their reactivation of a diasporic identity through Bollywood’s representations of a successful Indian diasporic culture and their participation in South African Bollywood concerts and award ceremonies has provided an opportunity for young South African Indians to reimagine their diasporic Indian identity in ways that (re-)connect them to India and to an imagined global diaspora.
- Full Text:
- Date Issued: 2018
- Authors: Boshoff, Priscilla A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143494 , vital:38251 , DOI: 10.3138/topia.26.29
- Description: Bollywood’s popularity as a global cultural form has occurred at the same time as the valorization of difference in the South African political landscape. As the youngest members of the 19th-century labour diaspora, South African Indian youths are the inheritors of a conservative—yet adaptable—home culture amidst the marginalized identities of (post-)apartheid South Africa. Their desire to create an identity for themselves that encompasses their self-perception both as modern South African subjects and as guardians of their traditional home cultures is achieved through Bollywood, which speaks to its diasporic audiences through images of an idealized traditional yet modern India. While India is not a place of return for these youth, their reactivation of a diasporic identity through Bollywood’s representations of a successful Indian diasporic culture and their participation in South African Bollywood concerts and award ceremonies has provided an opportunity for young South African Indians to reimagine their diasporic Indian identity in ways that (re-)connect them to India and to an imagined global diaspora.
- Full Text:
- Date Issued: 2018
Innovation through education: rediscovering the lost generation
- Authors: Pieterse, Koot
- Subjects: Business incubators , Entrepreneurship , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20889 , vital:29411
- Description: Innovation implies the generation as well as the practical implementation of new ideas. These ideas could appear as new product opportunities, new markets or new management systems and business schools are ideally situated to promote their exploitation and implementation. This study emphasises the need for business schools to elevate innovation to one of the core values in their mission. The need for innovation in the local business environment is explored along with reasons why these opportunities have not always been pursued with the required vigour. The results of a literature study are represented, that demonstrate what initiatives on the incorporation of innovation into their activities have been taken by a selection of business schools around the world and the study is concluded by exploring similar opportunities open to the Business School of the Nelson Mandela Metropolitan University.
- Full Text:
- Authors: Pieterse, Koot
- Subjects: Business incubators , Entrepreneurship , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20889 , vital:29411
- Description: Innovation implies the generation as well as the practical implementation of new ideas. These ideas could appear as new product opportunities, new markets or new management systems and business schools are ideally situated to promote their exploitation and implementation. This study emphasises the need for business schools to elevate innovation to one of the core values in their mission. The need for innovation in the local business environment is explored along with reasons why these opportunities have not always been pursued with the required vigour. The results of a literature study are represented, that demonstrate what initiatives on the incorporation of innovation into their activities have been taken by a selection of business schools around the world and the study is concluded by exploring similar opportunities open to the Business School of the Nelson Mandela Metropolitan University.
- Full Text: