Probing the biocompatibility of biomedical interfaces using the Quartz Crystal Microbalance with Dissipation
- Authors: Cromhout, Mary
- Date: 2011
- Subjects: Biomedical materials , Nanostructured materials , Biomedical engineering , Quartz crystal microbalances , Blood proteins , Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4102 , http://hdl.handle.net/10962/d1010660
- Description: The biomedical application of nanotechnology has come into the spotlight, with the promise of ‘personalised’ therapeutics that couple early diagnosis with targeted therapeutic activity. Due to the rapid growth of the biomedical applications of nanoparticles, along with the lack of understanding concerning their interactions with biomolecules, there is a pressing need for the development of standard methods directed at investigating the effect of introducing these unique particles into the human body. The central aim of this research is to establish a platform directed at assessing the biological fate of pioneering therapeutic particulate agents, such as metallophthalocyanines (MPcs) and multi-walled carbon nanotubes (FMWCNTs). In particular, we proposed, that Quartz Crystal Microbalance with Dissipation (QCM-D) technology may be employed to assess the composition of blood protein corona deposited on the therapeutic surface, and subsequently assess the biocompatibility of such particles. The proposed method of protein detection utilises the nanogram sensitivity of QCM-D technology to monitor highly specific antibody-antigen interactions. In particular those interactions which occur when probe antibodies are used to detect adsorbed blood proteins deposited on target particle-modified sensor surfaces. Protein detection analysis was directed toward identification of surface bound human serum albumin, complement factor C3c, and human plasma fibrinogen. Preliminary analysis of generic biomedical surfaces indicated human serum albumin demonstrates a higher binding affinity towards positively charged surfaces (i.e. cysteamine self-assembled monolayer), followed by hydrophobic surfaces. Detection of complement C3c, corresponded with literature, where lower levels were detected on negatively charged surfaces (i.e. mercapto undecanoic acid self-assembled monolayer), and higher levels of more hydrophobic surfaces (i.e. 11-amino undecane thiol self-assembled monolayer). Human plasma fibrinogen was observed to favour hydrophilic over hydrophobic self-assembled monolayer surfaces, which was in accordance with literature. Application of the proposed protein detection method for biocompatibility analysis of target therapeutic molecules, namely metallophthalocyanines and acid functionalised multi-walled carbon nanotubes, demonstrated a dependence on modified-surface film characteristics, such as surface charge and topography with regards to human serum albumin and human plasma fibrinogen analysis representing new insights into their potential biomolecular interactions The highest levels of detected human serum albumin and complement C3c were detected on the GePcSmix-modified surfaces. AlPcSmix-modified surfaces analysis suggested the highest levels of human plasma fibrinogen. Two methods of acid functionalisation were employed, using both nitric and sulphuric acid, and pure nitric acid. A general increase in detected human serum albumin, corresponding with an increase in functionalisation time, was observed. Complement C3c detection suggested an increase in deposited complement C3c, with increasing functionalisation time, when assessing nitric acid functionalised multi-walled carbon nanotubes, and a decrease, with increasing functionalisation time, when assessing nitric and sulphuric acid functionalised multi-walled carbon nanotubes. Analysis of human plasma fibrinogen was inconclusive, as were cytotoxicity experiments utilising MCF-7 cells in the presence of metallophthalocyanine complexes, raising simultaneously important considerations for their application and study. In the first such detailed examination of its kind it was concluded that the proposed method of protein detection, using QCM-D, allows for the rudimentary but rapid means of analysis of select protein corona deposited on particulate biomedical surfaces.
- Full Text:
- Date Issued: 2011
- Authors: Cromhout, Mary
- Date: 2011
- Subjects: Biomedical materials , Nanostructured materials , Biomedical engineering , Quartz crystal microbalances , Blood proteins , Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4102 , http://hdl.handle.net/10962/d1010660
- Description: The biomedical application of nanotechnology has come into the spotlight, with the promise of ‘personalised’ therapeutics that couple early diagnosis with targeted therapeutic activity. Due to the rapid growth of the biomedical applications of nanoparticles, along with the lack of understanding concerning their interactions with biomolecules, there is a pressing need for the development of standard methods directed at investigating the effect of introducing these unique particles into the human body. The central aim of this research is to establish a platform directed at assessing the biological fate of pioneering therapeutic particulate agents, such as metallophthalocyanines (MPcs) and multi-walled carbon nanotubes (FMWCNTs). In particular, we proposed, that Quartz Crystal Microbalance with Dissipation (QCM-D) technology may be employed to assess the composition of blood protein corona deposited on the therapeutic surface, and subsequently assess the biocompatibility of such particles. The proposed method of protein detection utilises the nanogram sensitivity of QCM-D technology to monitor highly specific antibody-antigen interactions. In particular those interactions which occur when probe antibodies are used to detect adsorbed blood proteins deposited on target particle-modified sensor surfaces. Protein detection analysis was directed toward identification of surface bound human serum albumin, complement factor C3c, and human plasma fibrinogen. Preliminary analysis of generic biomedical surfaces indicated human serum albumin demonstrates a higher binding affinity towards positively charged surfaces (i.e. cysteamine self-assembled monolayer), followed by hydrophobic surfaces. Detection of complement C3c, corresponded with literature, where lower levels were detected on negatively charged surfaces (i.e. mercapto undecanoic acid self-assembled monolayer), and higher levels of more hydrophobic surfaces (i.e. 11-amino undecane thiol self-assembled monolayer). Human plasma fibrinogen was observed to favour hydrophilic over hydrophobic self-assembled monolayer surfaces, which was in accordance with literature. Application of the proposed protein detection method for biocompatibility analysis of target therapeutic molecules, namely metallophthalocyanines and acid functionalised multi-walled carbon nanotubes, demonstrated a dependence on modified-surface film characteristics, such as surface charge and topography with regards to human serum albumin and human plasma fibrinogen analysis representing new insights into their potential biomolecular interactions The highest levels of detected human serum albumin and complement C3c were detected on the GePcSmix-modified surfaces. AlPcSmix-modified surfaces analysis suggested the highest levels of human plasma fibrinogen. Two methods of acid functionalisation were employed, using both nitric and sulphuric acid, and pure nitric acid. A general increase in detected human serum albumin, corresponding with an increase in functionalisation time, was observed. Complement C3c detection suggested an increase in deposited complement C3c, with increasing functionalisation time, when assessing nitric acid functionalised multi-walled carbon nanotubes, and a decrease, with increasing functionalisation time, when assessing nitric and sulphuric acid functionalised multi-walled carbon nanotubes. Analysis of human plasma fibrinogen was inconclusive, as were cytotoxicity experiments utilising MCF-7 cells in the presence of metallophthalocyanine complexes, raising simultaneously important considerations for their application and study. In the first such detailed examination of its kind it was concluded that the proposed method of protein detection, using QCM-D, allows for the rudimentary but rapid means of analysis of select protein corona deposited on particulate biomedical surfaces.
- Full Text:
- Date Issued: 2011
Prof Nyokong receives another Science award
- Authors: Matiwana, Zamuxolo
- Date: 2011
- Subjects: Nyokong, Tebello , International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM)
- Language: English
- Type: Article , text
- Identifier: vital:7182 , http://hdl.handle.net/10962/d1006267 , Nyokong, Tebello
- Description: The Rhodes University professor of Medicinal Chemistry and Nanotechnology, Tebello Nyokong, says the Award for her Scientific Achievements by the International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM) is an honour, especially since it is awarded in memory of the centenary of the first Nobel Prize in Chemistry awarded to a woman: Marie Curie.
- Full Text:
- Date Issued: 2011
- Authors: Matiwana, Zamuxolo
- Date: 2011
- Subjects: Nyokong, Tebello , International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM)
- Language: English
- Type: Article , text
- Identifier: vital:7182 , http://hdl.handle.net/10962/d1006267 , Nyokong, Tebello
- Description: The Rhodes University professor of Medicinal Chemistry and Nanotechnology, Tebello Nyokong, says the Award for her Scientific Achievements by the International Conference on Frontiers of Polymers and Advanced Materiel (ICFPAM) is an honour, especially since it is awarded in memory of the centenary of the first Nobel Prize in Chemistry awarded to a woman: Marie Curie.
- Full Text:
- Date Issued: 2011
Proposed South African management framework for the implementation of the International Convention for the Control and Management of Ships' Ballast Water and Sediments
- Authors: Nolting, Janine
- Date: 2011
- Subjects: Ships -- Fouling Discharge of ballast water -- Environmental aspects International Convention for the Control and Management of Ships' Ballast Water and Sediments Nonindigenous aquatic pests -- Law and legislation Marine fouling organisms -- Law and legislation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:786 , http://hdl.handle.net/10962/d1003907
- Description: South Africa, strategically situated at the southern tip of Africa, is edged on three sides by almost 3000 km of coastline surrounded by the Indian Ocean and the Atlantic Ocean (South African Tourism, 2011). This vast ocean expanse is responsible for conveying approximately 96% of South Africa’s exports (Brand South Africa, 2011). Despite the positive economic effects of the shipping industry, translocation of harmful organisms and pathogens via ballast water and sediments inside ballast water tanks has far reaching global environmental (and economic) impacts (Oliviera, 2008:1; David and Gollasch, 2008:1966). Ballast water is the water that is taken on in order to manage the draft of the ship, to help with propulsion, manoeuvrability, trim control, list and stability (Oliviera, 2008:2). The discharge of ballast water into the world’s oceans has resulted in the transfer of ecologically harmful sea-life into non-native environments (IMO, 2011), resulting in major environmental threats to our oceans (Bax, Williamson, Aguero, Gonzalez and Geeves, 2003:313). Various international documents have been developed to deal with the ballast water issue, culminating in the introduction of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (“the Convention”) in 2004. The Convention aims at achieving a reduction in the transfer and subsequent impacts of aquatic organisms via the ballast water and sediment of ships. On a local level, South Africa does not have direct legislation or regulations dealing with ballast water (Duncan, 2007:34) and relies on the combination of a number of pieces of legislation relating to environmental management, coastal management, biodiversity, alien invasive species control, port control and ship safety (National Environmental Management Act, 1998, National Environmental Management: Biodiversity Act, 2004, National Environmental Management: Integrated Coastal Management Act, 2009, National Ports Act, 2005 and Merchant Shipping Act, 1951). Although the Convention was ratified by South Africa in 2008 (Department of International Relations and Cooperation, 2011) it is still not in force and there still exists no other consolidated legal mechanism through which ballast water is managed. This research has investigated the various roles, responsibilities and mandates of South African competent authorities under the aforementioned legislation in managing ballast water, and has determined that there is definite legislative and institutional fragmentation as well as overlaps. A comparative analysis of management frameworks developed both locally and internationally was conducted in order to develop a management framework for ballast water management in South Africa. Various legislative, institutional and functional aspects were identified and adapted for inclusion in a South African management framework. A co-ordinated approach to ballast water management has been developed in the management framework which is anticipated to result in more definitive roles and responsibilities of the various South African departments involved in the management of ballast water and implementation of the Convention.
- Full Text:
- Date Issued: 2011
- Authors: Nolting, Janine
- Date: 2011
- Subjects: Ships -- Fouling Discharge of ballast water -- Environmental aspects International Convention for the Control and Management of Ships' Ballast Water and Sediments Nonindigenous aquatic pests -- Law and legislation Marine fouling organisms -- Law and legislation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:786 , http://hdl.handle.net/10962/d1003907
- Description: South Africa, strategically situated at the southern tip of Africa, is edged on three sides by almost 3000 km of coastline surrounded by the Indian Ocean and the Atlantic Ocean (South African Tourism, 2011). This vast ocean expanse is responsible for conveying approximately 96% of South Africa’s exports (Brand South Africa, 2011). Despite the positive economic effects of the shipping industry, translocation of harmful organisms and pathogens via ballast water and sediments inside ballast water tanks has far reaching global environmental (and economic) impacts (Oliviera, 2008:1; David and Gollasch, 2008:1966). Ballast water is the water that is taken on in order to manage the draft of the ship, to help with propulsion, manoeuvrability, trim control, list and stability (Oliviera, 2008:2). The discharge of ballast water into the world’s oceans has resulted in the transfer of ecologically harmful sea-life into non-native environments (IMO, 2011), resulting in major environmental threats to our oceans (Bax, Williamson, Aguero, Gonzalez and Geeves, 2003:313). Various international documents have been developed to deal with the ballast water issue, culminating in the introduction of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (“the Convention”) in 2004. The Convention aims at achieving a reduction in the transfer and subsequent impacts of aquatic organisms via the ballast water and sediment of ships. On a local level, South Africa does not have direct legislation or regulations dealing with ballast water (Duncan, 2007:34) and relies on the combination of a number of pieces of legislation relating to environmental management, coastal management, biodiversity, alien invasive species control, port control and ship safety (National Environmental Management Act, 1998, National Environmental Management: Biodiversity Act, 2004, National Environmental Management: Integrated Coastal Management Act, 2009, National Ports Act, 2005 and Merchant Shipping Act, 1951). Although the Convention was ratified by South Africa in 2008 (Department of International Relations and Cooperation, 2011) it is still not in force and there still exists no other consolidated legal mechanism through which ballast water is managed. This research has investigated the various roles, responsibilities and mandates of South African competent authorities under the aforementioned legislation in managing ballast water, and has determined that there is definite legislative and institutional fragmentation as well as overlaps. A comparative analysis of management frameworks developed both locally and internationally was conducted in order to develop a management framework for ballast water management in South Africa. Various legislative, institutional and functional aspects were identified and adapted for inclusion in a South African management framework. A co-ordinated approach to ballast water management has been developed in the management framework which is anticipated to result in more definitive roles and responsibilities of the various South African departments involved in the management of ballast water and implementation of the Convention.
- Full Text:
- Date Issued: 2011
Quantifying crop damage by Grey crowned crane balearica regulorum regulorum and evaluating changes in crane distribution in the North Eastern Cape, South Africa
- Authors: Van Niekerk, Mark Harry
- Date: 2011
- Subjects: Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5749 , http://hdl.handle.net/10962/d1005436 , Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Description: Complaints of crop damage by cranes on planted maize in the North Eastern Cape, South Africa, have been increasing since the mid-1990‘s, and in some instances severe losses have been reported. Crop damage by the Grey Crowned Crane Balearica regulorum regulorum near the town of Maclear (31º04´S 28º22´E), has been quantified over two growing seasons, and assessed relative to losses caused by foraging Cape Crows Corvus capensis and other feeding damage assumed to be caused by insects. Twelve fields were selected based on previous patterns of crop depredation. Maize seed in seven of the fields was treated with the chemical ‗Gaucho‘ and five fields were planted with untreated maize. In order to determine the source of losses, twenty quadrats (4 m x 4 m) randomly distributed within each field were visited on average every second day, for a period of up to twenty eight days. Results indicate that seed treatments do act as a deterrent to feeding by both cranes and crows, however crane damage is generally insignificant compared to other sources of damage. My study also reviewed past sightings data of the Grey Crowned Crane in an effort to determine if the conversion of former grassland to plantations in this region may have increased foraging activity in maize fields. The data did not allow for clear-cut conclusions regarding changes in distribution or population trends. Conclusions provide direct input into the management of agricultural areas by enabling landowners to take steps to mitigate crop damage. These mitigation measures may either involve the application of seed treatments, or the planting of low risk crops in high risk areas. Future studies should consider the ppossible detrimental effects of chemical seed treatments on crane biology.
- Full Text:
- Date Issued: 2011
- Authors: Van Niekerk, Mark Harry
- Date: 2011
- Subjects: Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5749 , http://hdl.handle.net/10962/d1005436 , Cranes (Birds) -- South Africa -- Eastern Cape , Cranes (Birds) -- Geographical distribution -- South Africa -- Eastern Cape , Cranes (Birds) -- Behavior -- South Africa -- Eastern Cape , Cranes (Birds) -- Food -- South Africa -- Eastern Cape , Corn -- Effect of grazing on -- South Africa -- Eastern Cape
- Description: Complaints of crop damage by cranes on planted maize in the North Eastern Cape, South Africa, have been increasing since the mid-1990‘s, and in some instances severe losses have been reported. Crop damage by the Grey Crowned Crane Balearica regulorum regulorum near the town of Maclear (31º04´S 28º22´E), has been quantified over two growing seasons, and assessed relative to losses caused by foraging Cape Crows Corvus capensis and other feeding damage assumed to be caused by insects. Twelve fields were selected based on previous patterns of crop depredation. Maize seed in seven of the fields was treated with the chemical ‗Gaucho‘ and five fields were planted with untreated maize. In order to determine the source of losses, twenty quadrats (4 m x 4 m) randomly distributed within each field were visited on average every second day, for a period of up to twenty eight days. Results indicate that seed treatments do act as a deterrent to feeding by both cranes and crows, however crane damage is generally insignificant compared to other sources of damage. My study also reviewed past sightings data of the Grey Crowned Crane in an effort to determine if the conversion of former grassland to plantations in this region may have increased foraging activity in maize fields. The data did not allow for clear-cut conclusions regarding changes in distribution or population trends. Conclusions provide direct input into the management of agricultural areas by enabling landowners to take steps to mitigate crop damage. These mitigation measures may either involve the application of seed treatments, or the planting of low risk crops in high risk areas. Future studies should consider the ppossible detrimental effects of chemical seed treatments on crane biology.
- Full Text:
- Date Issued: 2011
Queer transgressions : the choreographing of a male homosexual presence with reference to selected choreographers
- Authors: De Boer, Kyle Dylan
- Date: 2011
- Subjects: Queer theory , Gender identity in dance , Homosexuality in dance , Homosexuality and dance , Male homosexuality , Dance -- South Africa , Choreographers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2161 , http://hdl.handle.net/10962/d1009442
- Description: Queer Transgressions: The choreographing of a male homosexual presence with reference to selected choreographers explores queer identity and in particular representations of a male homosexual presence in dance. Within the methodological framework of dance studies and queer theory I explore the ―self fashioning‖ of my male homosexual presence in dance. This is achieved by critically deconstructing my choreographic process when making choreography. Therefore this thesis is informed by both academic research and my self-reflexive experience of choreography and dance performance. The deconstruction of my autobiography and choreographic process is discussed with reference to both international and South African queer choreographers. This means that by accounting for my own experiences and approaches toward representing a male homosexual presence in dance, I explore the history and engagements of other queer choreographers also creating such representations. I therefore examine the works of selected choreographers and chart the development of the representation of a male homosexual presence in dance. By exploring the choreographic process of other queer choreographers I identify choreographic tactics that queer choreographers are using when making work. From this point of departure I shift the focus away from international queer choreographers and provide insight into the choreographic processes of South African queer choreographers. By accounting for the works and choreographic processes of South African choreographers, I provide a context in which my choreographic explorations on the subject matter can take place. This choreographic exploration manifests itself through a self-reflexive/autobiographic account on the research and practice of my choreographic process. During my choreographic exploration I set the challenge to both engage with and explore further, established ―queering tactics. This is done with the intention to reveal and create representations of a male homosexual presence in dance.
- Full Text:
- Date Issued: 2011
- Authors: De Boer, Kyle Dylan
- Date: 2011
- Subjects: Queer theory , Gender identity in dance , Homosexuality in dance , Homosexuality and dance , Male homosexuality , Dance -- South Africa , Choreographers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2161 , http://hdl.handle.net/10962/d1009442
- Description: Queer Transgressions: The choreographing of a male homosexual presence with reference to selected choreographers explores queer identity and in particular representations of a male homosexual presence in dance. Within the methodological framework of dance studies and queer theory I explore the ―self fashioning‖ of my male homosexual presence in dance. This is achieved by critically deconstructing my choreographic process when making choreography. Therefore this thesis is informed by both academic research and my self-reflexive experience of choreography and dance performance. The deconstruction of my autobiography and choreographic process is discussed with reference to both international and South African queer choreographers. This means that by accounting for my own experiences and approaches toward representing a male homosexual presence in dance, I explore the history and engagements of other queer choreographers also creating such representations. I therefore examine the works of selected choreographers and chart the development of the representation of a male homosexual presence in dance. By exploring the choreographic process of other queer choreographers I identify choreographic tactics that queer choreographers are using when making work. From this point of departure I shift the focus away from international queer choreographers and provide insight into the choreographic processes of South African queer choreographers. By accounting for the works and choreographic processes of South African choreographers, I provide a context in which my choreographic explorations on the subject matter can take place. This choreographic exploration manifests itself through a self-reflexive/autobiographic account on the research and practice of my choreographic process. During my choreographic exploration I set the challenge to both engage with and explore further, established ―queering tactics. This is done with the intention to reveal and create representations of a male homosexual presence in dance.
- Full Text:
- Date Issued: 2011
Race, class and inequality: an exploration of the scholarship of Professor Bernard Magubane
- Authors: Tanyanyiwa, Precious
- Date: 2011
- Subjects: Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3324 , http://hdl.handle.net/10962/d1003112 , Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Description: This thesis begins with the assumption that the theory of academic dependency provides an adequate framework within which the relationship between social science communities in the North and South can be understood. Present problems of social scientists in the South have very often been attributed to this dependence and it has been concluded that academic dependence has resulted in an uncritical and imitative approach to ideas and concepts from the West (Alatas, 2000). This dependence has also resulted in the general regression among social scientists based in the South and in a marginalisation of their works within the social science community no matter how significant and original they may be. The problematic invisibility of the works of prominent South African scholars is a dimension of a wider crisis of academic dependence, if unchecked this current trend will also reinforce academic dependence. From the nature of the problems generated by academic dependence, it is obvious that there is a need for an intellectual emancipation movement. This movement may take different forms that may range from but are not limited to a commitment to endogeneity which involves among other things, knowledge production that takes South African local conditions seriously enough to be the basis for the development of distinct conceptual ideas and theories. This requires transcending the tendency to use ‘the local’ primarily as a tool for data collection and theoretical framing done from the global north. Secondly, there is a need to take the local, indigenous, ontological narratives seriously enough to serve as source codes for works of distinct epistemological value and exemplary ideas within the global project of knowledge production. Endogeneity in the context of African knowledge production should also involve an intellectual standpoint derived from a rootedness in the African conditions; a centring of African ontological discourses and experiences as the basis of intellectual work (Adesina, 2008: 135). In this study, it is suggested that the recommendations highlighted above can only succeed if scholars make an effort to actually engage with locally produced knowledge. There is therefore a need to make greater efforts to know each other’s work on Africa. This demand is not to appease individual egos but it is essential for progress in scientific work. African communities will benefit from drawing with greater catholicity from the well–spring of knowledge about Africa generated by Africans. In the South African context, transcending academic dependence in the new generation of young academics requires engagement with the work of our local scholars who have devoted their lives to knowledge production. This thesis explores the scholarship of Professor Bernard Magubane by engaging with his works on race, class and inequality by locating his works within the wider debates on race, class and inequality in South Africa. The specific contributions of Professor Magubane to the enterprise of knowledge production are identified and discussed in relation to his critique of Western social science in its application to Africa. The making of Professor Magubane’s life, his career, scholarship and biography details are analysed with the intention of showing their influence on Magubane as a Scholar. The examination of Professor Magubane’s intellectual and biographical accounts help to explain the details, contexts and implications of his theoretical paradigm shifts. This helps prove that Professor Magubane’s experiences and theoretical positions were socially and historically constituted. The research from which this thesis derives is part of an NRF-funded project, on Endogeneity and Modern Sociology in South Africa, under the direction of Professor Jimi Adesina.
- Full Text:
- Date Issued: 2011
- Authors: Tanyanyiwa, Precious
- Date: 2011
- Subjects: Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3324 , http://hdl.handle.net/10962/d1003112 , Magubane, Bernard -- Knowledge and learning , South Africa -- Race relations , Sociology -- South Africa , Race -- South Africa , Equality -- South Africa , Research -- South Africa , South Africa -- Social policy , Social classes -- South Africa
- Description: This thesis begins with the assumption that the theory of academic dependency provides an adequate framework within which the relationship between social science communities in the North and South can be understood. Present problems of social scientists in the South have very often been attributed to this dependence and it has been concluded that academic dependence has resulted in an uncritical and imitative approach to ideas and concepts from the West (Alatas, 2000). This dependence has also resulted in the general regression among social scientists based in the South and in a marginalisation of their works within the social science community no matter how significant and original they may be. The problematic invisibility of the works of prominent South African scholars is a dimension of a wider crisis of academic dependence, if unchecked this current trend will also reinforce academic dependence. From the nature of the problems generated by academic dependence, it is obvious that there is a need for an intellectual emancipation movement. This movement may take different forms that may range from but are not limited to a commitment to endogeneity which involves among other things, knowledge production that takes South African local conditions seriously enough to be the basis for the development of distinct conceptual ideas and theories. This requires transcending the tendency to use ‘the local’ primarily as a tool for data collection and theoretical framing done from the global north. Secondly, there is a need to take the local, indigenous, ontological narratives seriously enough to serve as source codes for works of distinct epistemological value and exemplary ideas within the global project of knowledge production. Endogeneity in the context of African knowledge production should also involve an intellectual standpoint derived from a rootedness in the African conditions; a centring of African ontological discourses and experiences as the basis of intellectual work (Adesina, 2008: 135). In this study, it is suggested that the recommendations highlighted above can only succeed if scholars make an effort to actually engage with locally produced knowledge. There is therefore a need to make greater efforts to know each other’s work on Africa. This demand is not to appease individual egos but it is essential for progress in scientific work. African communities will benefit from drawing with greater catholicity from the well–spring of knowledge about Africa generated by Africans. In the South African context, transcending academic dependence in the new generation of young academics requires engagement with the work of our local scholars who have devoted their lives to knowledge production. This thesis explores the scholarship of Professor Bernard Magubane by engaging with his works on race, class and inequality by locating his works within the wider debates on race, class and inequality in South Africa. The specific contributions of Professor Magubane to the enterprise of knowledge production are identified and discussed in relation to his critique of Western social science in its application to Africa. The making of Professor Magubane’s life, his career, scholarship and biography details are analysed with the intention of showing their influence on Magubane as a Scholar. The examination of Professor Magubane’s intellectual and biographical accounts help to explain the details, contexts and implications of his theoretical paradigm shifts. This helps prove that Professor Magubane’s experiences and theoretical positions were socially and historically constituted. The research from which this thesis derives is part of an NRF-funded project, on Endogeneity and Modern Sociology in South Africa, under the direction of Professor Jimi Adesina.
- Full Text:
- Date Issued: 2011
Raw phones: the domestication of mobile phones amongst young adults in Hooggenoeg, Grahamstown
- Authors: Schoon, Alette Jeanne
- Date: 2011
- Subjects: Cell phones -- Social aspects -- South Africa -- Grahamstown Communication -- Sex differences -- South Africa -- Grahamstown Social media -- South Africa -- Grahamstown Interpersonal communication -- Technological innovations -- Social aspects -- South Africa -- Grahamstown Communication and culture -- South Africa -- Grahamstown Online social networks -- Social aspects -- South Africa -- Grahamstown Mobile communication systems -- Social aspects -- South Africa -- Grahamstown Identity (Psychology) in youth Colored people (South Africa) -- Social life and customs -- South Africa -- Grahamstown Colored people (South Africa) -- Ethnic identity -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3482 , http://hdl.handle.net/10962/d1002937
- Description: This dissertation examines the meanings that young adults give to their mobile phones in the township of Hooggenoeg in Grahamstown in the Eastern Cape. The research was predominantly conducted through individual interviews with nine young adults as well as two small gender-based focus groups. Participant observation as well as a close reading of the popular mobile website Outoilet also contributed to the study. Drawing on Silverstone, Hirsch and Morley’s (1992) work into the meanings attributed to the mobile phone through the domestication processes of appropriation, objectification, incorporation and conversion, the study argues for the heterogeneous roles defined for mobile phones as they are integrated into different cultural contexts. The term ‘raw phones’ in the thesis title refers to a particular cultural understanding of respectability in mainly working-class ‘coloured’¹ communities in South Africa, as described by Salo (2007) and Ross (2010), in which race, class and gender converge in the construction of the respectable person’s opposite – a lascivious, almost certainly female, dependent, black and primitive ‘raw’ Other. The study argues that in Hooggenoeg, the mobile phone becomes part of semantic processes that define both respectability and ‘rawness’ , thus helping to reproduce social relations in this community along lines of race, class and gender. A major focus of the study is the instant messaging application MXit, and how it assists in the social production of space, by helping to constitute both private and dispersed network spaces of virtual communication, in a setting where social life is otherwise very public, and social networks outside of cyberspace are densely contiguous and localised. In contrast, gossip mobile website Outoilet seems to intensify this contiguous experience of space. My findings contest generalised claims, predominantly from the developed world, which assert that the mobile phone promotes mobility and an individualised society, and show that in particular contexts it may in fact promote immobility and create a collective sociability.
- Full Text:
- Date Issued: 2011
- Authors: Schoon, Alette Jeanne
- Date: 2011
- Subjects: Cell phones -- Social aspects -- South Africa -- Grahamstown Communication -- Sex differences -- South Africa -- Grahamstown Social media -- South Africa -- Grahamstown Interpersonal communication -- Technological innovations -- Social aspects -- South Africa -- Grahamstown Communication and culture -- South Africa -- Grahamstown Online social networks -- Social aspects -- South Africa -- Grahamstown Mobile communication systems -- Social aspects -- South Africa -- Grahamstown Identity (Psychology) in youth Colored people (South Africa) -- Social life and customs -- South Africa -- Grahamstown Colored people (South Africa) -- Ethnic identity -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3482 , http://hdl.handle.net/10962/d1002937
- Description: This dissertation examines the meanings that young adults give to their mobile phones in the township of Hooggenoeg in Grahamstown in the Eastern Cape. The research was predominantly conducted through individual interviews with nine young adults as well as two small gender-based focus groups. Participant observation as well as a close reading of the popular mobile website Outoilet also contributed to the study. Drawing on Silverstone, Hirsch and Morley’s (1992) work into the meanings attributed to the mobile phone through the domestication processes of appropriation, objectification, incorporation and conversion, the study argues for the heterogeneous roles defined for mobile phones as they are integrated into different cultural contexts. The term ‘raw phones’ in the thesis title refers to a particular cultural understanding of respectability in mainly working-class ‘coloured’¹ communities in South Africa, as described by Salo (2007) and Ross (2010), in which race, class and gender converge in the construction of the respectable person’s opposite – a lascivious, almost certainly female, dependent, black and primitive ‘raw’ Other. The study argues that in Hooggenoeg, the mobile phone becomes part of semantic processes that define both respectability and ‘rawness’ , thus helping to reproduce social relations in this community along lines of race, class and gender. A major focus of the study is the instant messaging application MXit, and how it assists in the social production of space, by helping to constitute both private and dispersed network spaces of virtual communication, in a setting where social life is otherwise very public, and social networks outside of cyberspace are densely contiguous and localised. In contrast, gossip mobile website Outoilet seems to intensify this contiguous experience of space. My findings contest generalised claims, predominantly from the developed world, which assert that the mobile phone promotes mobility and an individualised society, and show that in particular contexts it may in fact promote immobility and create a collective sociability.
- Full Text:
- Date Issued: 2011
Regional application of the Pitman monthly rainfall-runoff model in Southern Africa incorporating uncertainty
- Authors: Kapangaziwiri, Evison
- Date: 2011
- Subjects: Water supply -- Africa, Southern Water supply -- Measurement -- Africa, Southern Hydrology -- Mathematical models -- Africa, Southern Hydrologic models Rain and rainfall -- Mathematical models -- Africa, Southern Runoff -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6037 , http://hdl.handle.net/10962/d1006178
- Description: Climate change and a growing demand for freshwater resources due to population increases and socio-economic changes will make water a limiting factor (in terms of both quantity and quality) in development. The need for reliable quantitative estimates of water availability cannot be over-emphasised. However, there is frequently a paucity of the data required for this quantification as many basins, especially in the developing world, are inadequately equipped with monitoring networks. Existing networks are also shrinking due mainly to shortages in human and financial resources. Over the past few decades mathematical models have been used to bridge the data gap by generating datasets for use in management and policy making. In southern Africa, the Pitman monthly rainfall-runoff model has enjoyed relatively popular use as a water resources estimation tool. However, it is acknowledged that models are abstractions of reality and the data used to drive them is imperfect, making the model outputs uncertain. While there is acknowledgement of the limitations of modelled data in the southern African region among water practitioners, there has been little effort to explicitly quantify and account for this uncertainty in water resources estimation tools and explore how it affects the decision making process. Uncertainty manifests itself in three major areas of the modelling chain; the input data used to force the model, the parameter estimation process and the model structural errors. A previous study concluded that the parameter estimation process for the Pitman model contributed more to the global uncertainty of the model than other sources. While the literature abounds with uncertainty estimation techniques, many of these are dependent on observations and are therefore unlikely to be easily applicable to the southern African region where there is an acute shortage of such data. This study focuses on two aspects of making hydrologic predictions in ungauged basins. Firstly, the study advocates the development of an a priori parameter estimation process for the Pitman model and secondly, uses indices of hydrological functional behaviour to condition and reduce predictive uncertainty in both gauged and ungauged basins. In this approach all the basins are treated as ungauged, while the historical records in the gauged basins are used to develop regional indices of expected hydrological behaviour and assess the applicability of these methods. Incorporating uncertainty into the hydrologic estimation tools used in southern Africa entails rethinking the way the uncertain results can be used in further analysis and how they will be interpreted by stakeholders. An uncertainty framework is proposed. The framework is made up of a number of components related to the estimation of the prior distribution of the parameters, used to generate output ensembles which are then assessed and constrained using regionalised indices of basin behavioural responses. This is premised on such indices being based on the best available knowledge covering different regions. This framework is flexible enough to be used with any model structure to ensure consistent and comparable results. While the aim is to eventually apply the uncertainty framework in the southern African region, this study reports on the preliminary work on the development and testing of the framework components based on South African basins. This is necessitated by the variations in the availability and quality of the data across the region. Uncertainty in the parameter estimation process was incorporated by assuming uncertainty in the physical and hydro-meteorological data used to directly quantify the parameter. This uncertainty was represented by the range of variability of these basin characteristics and probability distribution functions were developed to account for this uncertainty and propagate it through the estimation process to generate posterior distributions for the parameters. The results show that the framework has a great deal of potential but can still be improved. In general, the estimated uncertain parameters managed to produce hydrologically realistic model outputs capturing the expected regimes across the different hydro-climatic and geo-physical gradients examined. The regional relationships for the three indices developed and tested in this study were in general agreement with existing knowledge and managed to successfully provide a multi-criteria conditioning of the model output ensembles. The feedback loop included in the framework enabled a systematic re-examination of the estimation procedures for both the parameters and the indices when inconsistencies in the results were identified. This improved results. However, there is need to carefully examine the issues and problems that may arise within other basins outside South Africa and develop guidelines for the use of the framework. , iText 1.4.6 (by lowagie.com)
- Full Text:
- Date Issued: 2011
- Authors: Kapangaziwiri, Evison
- Date: 2011
- Subjects: Water supply -- Africa, Southern Water supply -- Measurement -- Africa, Southern Hydrology -- Mathematical models -- Africa, Southern Hydrologic models Rain and rainfall -- Mathematical models -- Africa, Southern Runoff -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6037 , http://hdl.handle.net/10962/d1006178
- Description: Climate change and a growing demand for freshwater resources due to population increases and socio-economic changes will make water a limiting factor (in terms of both quantity and quality) in development. The need for reliable quantitative estimates of water availability cannot be over-emphasised. However, there is frequently a paucity of the data required for this quantification as many basins, especially in the developing world, are inadequately equipped with monitoring networks. Existing networks are also shrinking due mainly to shortages in human and financial resources. Over the past few decades mathematical models have been used to bridge the data gap by generating datasets for use in management and policy making. In southern Africa, the Pitman monthly rainfall-runoff model has enjoyed relatively popular use as a water resources estimation tool. However, it is acknowledged that models are abstractions of reality and the data used to drive them is imperfect, making the model outputs uncertain. While there is acknowledgement of the limitations of modelled data in the southern African region among water practitioners, there has been little effort to explicitly quantify and account for this uncertainty in water resources estimation tools and explore how it affects the decision making process. Uncertainty manifests itself in three major areas of the modelling chain; the input data used to force the model, the parameter estimation process and the model structural errors. A previous study concluded that the parameter estimation process for the Pitman model contributed more to the global uncertainty of the model than other sources. While the literature abounds with uncertainty estimation techniques, many of these are dependent on observations and are therefore unlikely to be easily applicable to the southern African region where there is an acute shortage of such data. This study focuses on two aspects of making hydrologic predictions in ungauged basins. Firstly, the study advocates the development of an a priori parameter estimation process for the Pitman model and secondly, uses indices of hydrological functional behaviour to condition and reduce predictive uncertainty in both gauged and ungauged basins. In this approach all the basins are treated as ungauged, while the historical records in the gauged basins are used to develop regional indices of expected hydrological behaviour and assess the applicability of these methods. Incorporating uncertainty into the hydrologic estimation tools used in southern Africa entails rethinking the way the uncertain results can be used in further analysis and how they will be interpreted by stakeholders. An uncertainty framework is proposed. The framework is made up of a number of components related to the estimation of the prior distribution of the parameters, used to generate output ensembles which are then assessed and constrained using regionalised indices of basin behavioural responses. This is premised on such indices being based on the best available knowledge covering different regions. This framework is flexible enough to be used with any model structure to ensure consistent and comparable results. While the aim is to eventually apply the uncertainty framework in the southern African region, this study reports on the preliminary work on the development and testing of the framework components based on South African basins. This is necessitated by the variations in the availability and quality of the data across the region. Uncertainty in the parameter estimation process was incorporated by assuming uncertainty in the physical and hydro-meteorological data used to directly quantify the parameter. This uncertainty was represented by the range of variability of these basin characteristics and probability distribution functions were developed to account for this uncertainty and propagate it through the estimation process to generate posterior distributions for the parameters. The results show that the framework has a great deal of potential but can still be improved. In general, the estimated uncertain parameters managed to produce hydrologically realistic model outputs capturing the expected regimes across the different hydro-climatic and geo-physical gradients examined. The regional relationships for the three indices developed and tested in this study were in general agreement with existing knowledge and managed to successfully provide a multi-criteria conditioning of the model output ensembles. The feedback loop included in the framework enabled a systematic re-examination of the estimation procedures for both the parameters and the indices when inconsistencies in the results were identified. This improved results. However, there is need to carefully examine the issues and problems that may arise within other basins outside South Africa and develop guidelines for the use of the framework. , iText 1.4.6 (by lowagie.com)
- Full Text:
- Date Issued: 2011
Relational processes enabling the balancing of academic work and motherhood: a grounded theory study with academic women at a South African university
- Authors: Poulos, Tessa
- Date: 2011
- Subjects: Working mothers -- South Africa -- Grahamstown Women in education -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Rhodes University -- Employees Motherhood -- South Africa -- Grahamstown Sex role in the work environment -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3038 , http://hdl.handle.net/10962/d1002547
- Description: Through the use of contextual data, this research study aims to explicate a theory about the experiences of academic women, who are also mothers, employed at a South African University. The research is interpretive in nature as it explores the women's accounts of the conflicts they face in striving to satisfy the demands of both their scholarly work and family responsibilities within multiple intersecting factors related to their personal/familial circumstances, and the strategic processes they engage in to manage the balance between these competing roles. The study followed a constructivist grounded theory design in an attempt to test the hypothesis (emerging from a prior pilot study) that the most significant enabling factors at work in the lives of these women comprise various relational support processes. The findings indicate that balancing academic work and mothering is a delicate activity that is sensitive to a number of facilitating as well as hindering factors. The participants revealed that they experience work-family role-conflict as a result of competing desires to dedicate themselves fully to both of these roles. The relational factors most prominently cited as being critical to enabling a work-family balance include the presence of a supportive partner, a support structure in the home in the form of an employed domestic helper, and the support derived from a 'shared experience' with other working mothers. Non-relational factors emanating from the unique quality of life afforded to mothers by employment within the particular case institution also emerged as being significantly enabling of a work-family balance for this group of academic mothers.
- Full Text:
- Date Issued: 2011
- Authors: Poulos, Tessa
- Date: 2011
- Subjects: Working mothers -- South Africa -- Grahamstown Women in education -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Rhodes University -- Employees Motherhood -- South Africa -- Grahamstown Sex role in the work environment -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3038 , http://hdl.handle.net/10962/d1002547
- Description: Through the use of contextual data, this research study aims to explicate a theory about the experiences of academic women, who are also mothers, employed at a South African University. The research is interpretive in nature as it explores the women's accounts of the conflicts they face in striving to satisfy the demands of both their scholarly work and family responsibilities within multiple intersecting factors related to their personal/familial circumstances, and the strategic processes they engage in to manage the balance between these competing roles. The study followed a constructivist grounded theory design in an attempt to test the hypothesis (emerging from a prior pilot study) that the most significant enabling factors at work in the lives of these women comprise various relational support processes. The findings indicate that balancing academic work and mothering is a delicate activity that is sensitive to a number of facilitating as well as hindering factors. The participants revealed that they experience work-family role-conflict as a result of competing desires to dedicate themselves fully to both of these roles. The relational factors most prominently cited as being critical to enabling a work-family balance include the presence of a supportive partner, a support structure in the home in the form of an employed domestic helper, and the support derived from a 'shared experience' with other working mothers. Non-relational factors emanating from the unique quality of life afforded to mothers by employment within the particular case institution also emerged as being significantly enabling of a work-family balance for this group of academic mothers.
- Full Text:
- Date Issued: 2011
Representing conflict: an analysis of The Chronicle's coverage of the Gukurahundi conflict in Zimbabwe between 1983 and 1986
- Authors: Santos, Phillip
- Date: 2011
- Subjects: The Chronicle (Zimbabwe) Zimbabwe -- History -- 1980- Zimbabwe -- Politics and government -- 1980- Mass media -- Political aspects -- Zimbabwe Mass media -- Moral and ethical aspects -- Zimbabwe Journalistic ethics -- Zimbabwe Journalism -- Objectivity -- Zimbabwe War in mass media -- Zimbabwe Violence in mass media -- Zimbabwe Mass media and peace -- Zimbabwe Discourse analysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3481 , http://hdl.handle.net/10962/d1002936
- Description: This research is premised on the understanding that media texts are discourses and that all discourses are functional, that is, they refer to things, issues and events, in meaningful and goal oriented ways. Nine articles are analysed to explicate the sorts of discourses that were promoted by The Chronicle during the Gukurahundi conflict in Zimbabwe between 1982 and 1986. It is argued that discourses in the news media are shaped by the role(s), the type(s) of journalism assumed by such media, and by the political environment in which the news media operate. The interplay between the roles, types of journalism practised, and the effect the political environment has on news discourses is assessed within the context of conflictual situations. This is done using insights from the theoretical position of peace journalism and its critique of professional or mainstream journalism as promoting war/violence journalism. Using the case of The Chronicle's reportage of the Gukurahundi conflict in Zimbabwe, it is concluded that, in performing the collaborative role, state owned/controlled media assume characteristics of war/violence journalism. On the other hand, it is concluded that The Chronicle developed practices consistent with peace journalism when it both espoused the facilitative role and journalistic objectivity. These findings undermine the conventional view among proponents of peace journalism that in times of conflict, the news media should be interventionist in favour of peace and that they should abandon the journalistic norm of objectivity which they argue, promotes war/violence journalism.
- Full Text:
- Date Issued: 2011
- Authors: Santos, Phillip
- Date: 2011
- Subjects: The Chronicle (Zimbabwe) Zimbabwe -- History -- 1980- Zimbabwe -- Politics and government -- 1980- Mass media -- Political aspects -- Zimbabwe Mass media -- Moral and ethical aspects -- Zimbabwe Journalistic ethics -- Zimbabwe Journalism -- Objectivity -- Zimbabwe War in mass media -- Zimbabwe Violence in mass media -- Zimbabwe Mass media and peace -- Zimbabwe Discourse analysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3481 , http://hdl.handle.net/10962/d1002936
- Description: This research is premised on the understanding that media texts are discourses and that all discourses are functional, that is, they refer to things, issues and events, in meaningful and goal oriented ways. Nine articles are analysed to explicate the sorts of discourses that were promoted by The Chronicle during the Gukurahundi conflict in Zimbabwe between 1982 and 1986. It is argued that discourses in the news media are shaped by the role(s), the type(s) of journalism assumed by such media, and by the political environment in which the news media operate. The interplay between the roles, types of journalism practised, and the effect the political environment has on news discourses is assessed within the context of conflictual situations. This is done using insights from the theoretical position of peace journalism and its critique of professional or mainstream journalism as promoting war/violence journalism. Using the case of The Chronicle's reportage of the Gukurahundi conflict in Zimbabwe, it is concluded that, in performing the collaborative role, state owned/controlled media assume characteristics of war/violence journalism. On the other hand, it is concluded that The Chronicle developed practices consistent with peace journalism when it both espoused the facilitative role and journalistic objectivity. These findings undermine the conventional view among proponents of peace journalism that in times of conflict, the news media should be interventionist in favour of peace and that they should abandon the journalistic norm of objectivity which they argue, promotes war/violence journalism.
- Full Text:
- Date Issued: 2011
Responses of intertidal macroalgae and associated fauna to interactive processes acting over multiple spatial scales
- Authors: Mostert, Bruce Petrus
- Date: 2011 , 2010-12-01
- Subjects: Biodiversity -- South Africa , Spatial ecology , Marine algae -- South Africa , Marine organisms -- Effect of water pollution on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5890 , http://hdl.handle.net/10962/d1013370
- Description: The decrease of biological diversity from low latitudes near the equator towards high latitudes is one of the most fundamental patterns noted in ecology. These trends have been the subject of numerous terrestrial and marine studies and have caused the proposal of several explanatory hypotheses. No single hypothesis has adequately accounted for these observed trends. Furthermore, large-scale patterns are frequently modified by processes acting at meso- to small-scales. It is imperative to understand the interaction of these processes to elucidate the mechanisms controlling the structure of intertidal assemblages. The main aim of this thesis was to test the influence of multiple processes at a range of spatial scales on biogenic engineers. Biogenic engineers, such as macroalgae, have been reported to be strongly influenced by processes such as grazing, biogeography and upwelling and subsequent effects are expected to be linked to their associated assemblages. I used infaunal assemblages associated with macroalgae as a model system to understand the interactive effects of meso-scale upwelling in conjunction with large-scale factors (regional and biogeographic). Three species of macroalgae, Hypnea spicifera, Champia lumbricalis and Bifurcaria brassicaeformis, inhabiting different but overlapping home ranges were used in this study. Smaller scale, physical attributes and the associated fauna of these algal species were compared. The effects of meso- to large-scale physical gradients on marine organisms have been investigated in many instances and resultant gradients in physical variables observed. This study was undertaken to investigate morphological trends exhibited by Hypnea spicifera and Champia lumbricalis to compare possible similarities between coastlines and to determine if inferred meso- to large-scale processes influence physical trends in a similar manner despite the coastlines being affected by different hydrodynamic processes. The macroalgae were located in two distinctly different upwelling regimes, Hypnea spicifera on the east and south coasts and Champia lumbricalis on the west coast. Upwelling (delivery of nutrients and primary production) was not found to be an important factor in determining the physical characteristics of macroalgae but there were clear patterns linked to latitude. Mean percentage cover of Hypnea spicifera was positively correlated with distance along the east and south coasts. Mean mass and mean surface area of H. spicifera were, however, negatively correlated with distance from Port St Johns. Mean frond length showed a negative trend but this relationship was not statistically significant. On the west coast, there was a significant increase in mean frond length from north to south for Champia lumbricalis. Mean surface area and mean mass of C. lumbricalis exhibited non-significant negative trends from north to south while there was a non-significant positive trend for mean percentage cover. Following the “Productivity Hypothesis”, these patterns from north to south along the coastlines of South Africa could have important implications for biodiversity associated with these algae. Many previous studies have focussed on the effects of upwelling on species (i.e. effects of nutrients and temperature) but have failed to separate this effect from large scale effects such as biogeography and latitudinal gradients. I tested the influence meso-scale upwelling, large-scale biogeographic processes and latitudinal gradients with two different species of macroalgae one on the east and south coasts of South Africa and the other on the west coast. Hypnea spicifera inhabits the east and south coasts of South Africa spanning two biogeographic provinces and is generally affected by relatively weak upwelling, whereas Champia lumbricalis inhabits the west coast spanning one biogeographic province which is subjected to intense persistent upwelling year round. Within the east and west coast biogeographic provinces there are, however, regions with both upwelling and non-upwelling. On the east and south coasts, entire assemblages differed significantly among the three Regions (St Lucia, Port Alfred and Knysna, while assemblages between upwelling/non-upwelling areas were not different. Assemblages on the different shores differed significantly from each other. There were no significant effects of region or upwelling for the number of individuals of Crustacea or Polychaeta, while Mollusca showed a significant effect of region. The number of individuals of other taxa showed a significant interaction of region and upwelling. Region had a significant effect on number of species of molluscs and other taxa, while there was no effect for either region or upwelling for the Crustacea or Polychaeta. In general different factors were shown to be important (region and shore) while upwelling was rarely important. On the west coast assemblages associated with C. lumbricalis were not influenced by region or upwelling but there were significant differences between shores. Region, upwelling ad shore did not affect number of individuals. There was a significant interaction of region and upwelling for the number of species of crustaceans, while numbers of species of Mollusca, Polychaeta and other taxa showed no effects. In general, regional factors strongly influenced most organisms, while upwelling played a minor role. Hypotheses about differences between upwelling and non-upwelling regions in terms of species abundances and composition due to the input of cold nutrient rich water were not supported. A link between the effects of larger-scale biogeographic factors and their influence on habitat forming taxa and the resultant effects on associated infauna would be a likely explanation for the patterns observed in this study. Diversity of assemblages is known to be influenced by the structural complexity of a habitat, increasing complexity increases the amount of available niches therefore potentially increasing the number of species found within that habitat. Three species of macroalgae, Hypnea spicifera, Champia lumbricalis and Bifurcaria brassicaeformis were selected on the basis of being structurally similar and having their distributional ranges overlap in order to elucidate the effects of structure and macroalgal species on associated assemblages. Hypnea spicifera is different in terms of surface area and biomass from Champia lumbricalis and Bifurcaria brassicaeformis. Assemblages of species found on the three rhodophytes showed both shore and the species of alga had significant effects on composition. Only numbers of individuals of molluscs were affected by the species of alga. Crustacea and Polychaeta showed an interaction of the species of alga with shore. In the case of this study, it is likely that the three species of macroalgae mitigate biological stressors such as predation and physical stressors such as wave exposure and desiccation. In general, meso-scale upwelling is suggested to be marginalised when considering the structuring of assemblages associated with macroalgae, while large scale biogeography has more of an influence. Within shores, assemblages were also strongly influenced by smaller-scale factors such as differences in the structure and species of alga. This study indicates the importance of investigating patterns across a range of spatial scales to gain a comprehensive understanding of factors influencing intertidal organisms.
- Full Text:
- Date Issued: 2011
- Authors: Mostert, Bruce Petrus
- Date: 2011 , 2010-12-01
- Subjects: Biodiversity -- South Africa , Spatial ecology , Marine algae -- South Africa , Marine organisms -- Effect of water pollution on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5890 , http://hdl.handle.net/10962/d1013370
- Description: The decrease of biological diversity from low latitudes near the equator towards high latitudes is one of the most fundamental patterns noted in ecology. These trends have been the subject of numerous terrestrial and marine studies and have caused the proposal of several explanatory hypotheses. No single hypothesis has adequately accounted for these observed trends. Furthermore, large-scale patterns are frequently modified by processes acting at meso- to small-scales. It is imperative to understand the interaction of these processes to elucidate the mechanisms controlling the structure of intertidal assemblages. The main aim of this thesis was to test the influence of multiple processes at a range of spatial scales on biogenic engineers. Biogenic engineers, such as macroalgae, have been reported to be strongly influenced by processes such as grazing, biogeography and upwelling and subsequent effects are expected to be linked to their associated assemblages. I used infaunal assemblages associated with macroalgae as a model system to understand the interactive effects of meso-scale upwelling in conjunction with large-scale factors (regional and biogeographic). Three species of macroalgae, Hypnea spicifera, Champia lumbricalis and Bifurcaria brassicaeformis, inhabiting different but overlapping home ranges were used in this study. Smaller scale, physical attributes and the associated fauna of these algal species were compared. The effects of meso- to large-scale physical gradients on marine organisms have been investigated in many instances and resultant gradients in physical variables observed. This study was undertaken to investigate morphological trends exhibited by Hypnea spicifera and Champia lumbricalis to compare possible similarities between coastlines and to determine if inferred meso- to large-scale processes influence physical trends in a similar manner despite the coastlines being affected by different hydrodynamic processes. The macroalgae were located in two distinctly different upwelling regimes, Hypnea spicifera on the east and south coasts and Champia lumbricalis on the west coast. Upwelling (delivery of nutrients and primary production) was not found to be an important factor in determining the physical characteristics of macroalgae but there were clear patterns linked to latitude. Mean percentage cover of Hypnea spicifera was positively correlated with distance along the east and south coasts. Mean mass and mean surface area of H. spicifera were, however, negatively correlated with distance from Port St Johns. Mean frond length showed a negative trend but this relationship was not statistically significant. On the west coast, there was a significant increase in mean frond length from north to south for Champia lumbricalis. Mean surface area and mean mass of C. lumbricalis exhibited non-significant negative trends from north to south while there was a non-significant positive trend for mean percentage cover. Following the “Productivity Hypothesis”, these patterns from north to south along the coastlines of South Africa could have important implications for biodiversity associated with these algae. Many previous studies have focussed on the effects of upwelling on species (i.e. effects of nutrients and temperature) but have failed to separate this effect from large scale effects such as biogeography and latitudinal gradients. I tested the influence meso-scale upwelling, large-scale biogeographic processes and latitudinal gradients with two different species of macroalgae one on the east and south coasts of South Africa and the other on the west coast. Hypnea spicifera inhabits the east and south coasts of South Africa spanning two biogeographic provinces and is generally affected by relatively weak upwelling, whereas Champia lumbricalis inhabits the west coast spanning one biogeographic province which is subjected to intense persistent upwelling year round. Within the east and west coast biogeographic provinces there are, however, regions with both upwelling and non-upwelling. On the east and south coasts, entire assemblages differed significantly among the three Regions (St Lucia, Port Alfred and Knysna, while assemblages between upwelling/non-upwelling areas were not different. Assemblages on the different shores differed significantly from each other. There were no significant effects of region or upwelling for the number of individuals of Crustacea or Polychaeta, while Mollusca showed a significant effect of region. The number of individuals of other taxa showed a significant interaction of region and upwelling. Region had a significant effect on number of species of molluscs and other taxa, while there was no effect for either region or upwelling for the Crustacea or Polychaeta. In general different factors were shown to be important (region and shore) while upwelling was rarely important. On the west coast assemblages associated with C. lumbricalis were not influenced by region or upwelling but there were significant differences between shores. Region, upwelling ad shore did not affect number of individuals. There was a significant interaction of region and upwelling for the number of species of crustaceans, while numbers of species of Mollusca, Polychaeta and other taxa showed no effects. In general, regional factors strongly influenced most organisms, while upwelling played a minor role. Hypotheses about differences between upwelling and non-upwelling regions in terms of species abundances and composition due to the input of cold nutrient rich water were not supported. A link between the effects of larger-scale biogeographic factors and their influence on habitat forming taxa and the resultant effects on associated infauna would be a likely explanation for the patterns observed in this study. Diversity of assemblages is known to be influenced by the structural complexity of a habitat, increasing complexity increases the amount of available niches therefore potentially increasing the number of species found within that habitat. Three species of macroalgae, Hypnea spicifera, Champia lumbricalis and Bifurcaria brassicaeformis were selected on the basis of being structurally similar and having their distributional ranges overlap in order to elucidate the effects of structure and macroalgal species on associated assemblages. Hypnea spicifera is different in terms of surface area and biomass from Champia lumbricalis and Bifurcaria brassicaeformis. Assemblages of species found on the three rhodophytes showed both shore and the species of alga had significant effects on composition. Only numbers of individuals of molluscs were affected by the species of alga. Crustacea and Polychaeta showed an interaction of the species of alga with shore. In the case of this study, it is likely that the three species of macroalgae mitigate biological stressors such as predation and physical stressors such as wave exposure and desiccation. In general, meso-scale upwelling is suggested to be marginalised when considering the structuring of assemblages associated with macroalgae, while large scale biogeography has more of an influence. Within shores, assemblages were also strongly influenced by smaller-scale factors such as differences in the structure and species of alga. This study indicates the importance of investigating patterns across a range of spatial scales to gain a comprehensive understanding of factors influencing intertidal organisms.
- Full Text:
- Date Issued: 2011
Rhodes University Graduation Ceremony 2011
- Authors: Rhodes University
- Date: 2011
- Language: English
- Type: text
- Identifier: vital:8136 , http://hdl.handle.net/10962/d1007246
- Description: Rhodes University Graduation Ceremonies [at] 1820 Settlers National Monument Thursday, 7 April at 18.00 [and] Friday, 8 April at 10:30; 14:30 & 18:00 [and] Saturday, 9 April at 10:30
- Full Text:
- Date Issued: 2011
- Authors: Rhodes University
- Date: 2011
- Language: English
- Type: text
- Identifier: vital:8136 , http://hdl.handle.net/10962/d1007246
- Description: Rhodes University Graduation Ceremonies [at] 1820 Settlers National Monument Thursday, 7 April at 18.00 [and] Friday, 8 April at 10:30; 14:30 & 18:00 [and] Saturday, 9 April at 10:30
- Full Text:
- Date Issued: 2011
Rhodes University Research Report 2011
- Rhodes University, Rhodes University Research Office, Roberts, Jaine, Connan, Verna, Dore, Sally
- Authors: Rhodes University , Rhodes University Research Office , Roberts, Jaine , Connan, Verna , Dore, Sally
- Date: 2011
- Language: English
- Type: Text
- Identifier: vital:566 , http://hdl.handle.net/10962/d1011981
- Description: [From Introduction] Rhodes University continued to show a gratifying and steady increase in overall accredited research outputs in 2011, and individual increases were experienced in all categories of output. Overall accredited units increased to 639.6 (a 12.7% increase on 2010), with a similar percentage increase in the DHET per capita output figure, which kept Rhodes in the position of third most productive university in South Africa in terms of accredited research. 51% of the outputs were due to publications, 25% to PhD graduations, and 24% to Masters graduations by thesis. The PhD contribution represented a record year, and a 30% increase over the number graduating in the preceding year. Our journal output, (which accounts for 86% of our total accredited publishing output for higher education subsidy purposes) grew by 5.9% from the 2010 level (to 309.61 units in 2011). The previous year had seen a 3% decline in this category. Coupled with Rhodes’ high volume of accredited journal outputs in relation to its size, a very pleasing quality measure was that 90% of journal outputs (by far the highest proportion of universities in the sector) appeared in international accredited journals. Our output from accredited conference proceedings, (which in 2011 amounted to 7% of our total accredited publishing output) grew by 3.5% to 24.22 units - from a small base where year-on-year variance in either direction is common. The book outputs (which in 2011 amounted to 7% of our total accredited publishing output) increased by 162% - again from a small base (moving up to 25.02 units), where year-on-year variance is expected. This category had seen a negative growth of 60.6% in the previous year. add my warm thanks and congratulations to all of our researchers, funders, collaborators, partners and students who contributed to the excellent accredited research results of 2011, as well as generated the many forms of scholarship that are not counted in the accreditation exercise, but which contribute much to the rich intellectual space that is Rhodes. I also thank all of the administrators who played a critical role in preparing the university’s meticulous audited submission. , A publication of the Rhodes Research Office, compiled and edited by Jaine Roberts and Verna Connan. Design and Layout: Sally Dore.
- Full Text:
- Date Issued: 2011
- Authors: Rhodes University , Rhodes University Research Office , Roberts, Jaine , Connan, Verna , Dore, Sally
- Date: 2011
- Language: English
- Type: Text
- Identifier: vital:566 , http://hdl.handle.net/10962/d1011981
- Description: [From Introduction] Rhodes University continued to show a gratifying and steady increase in overall accredited research outputs in 2011, and individual increases were experienced in all categories of output. Overall accredited units increased to 639.6 (a 12.7% increase on 2010), with a similar percentage increase in the DHET per capita output figure, which kept Rhodes in the position of third most productive university in South Africa in terms of accredited research. 51% of the outputs were due to publications, 25% to PhD graduations, and 24% to Masters graduations by thesis. The PhD contribution represented a record year, and a 30% increase over the number graduating in the preceding year. Our journal output, (which accounts for 86% of our total accredited publishing output for higher education subsidy purposes) grew by 5.9% from the 2010 level (to 309.61 units in 2011). The previous year had seen a 3% decline in this category. Coupled with Rhodes’ high volume of accredited journal outputs in relation to its size, a very pleasing quality measure was that 90% of journal outputs (by far the highest proportion of universities in the sector) appeared in international accredited journals. Our output from accredited conference proceedings, (which in 2011 amounted to 7% of our total accredited publishing output) grew by 3.5% to 24.22 units - from a small base where year-on-year variance in either direction is common. The book outputs (which in 2011 amounted to 7% of our total accredited publishing output) increased by 162% - again from a small base (moving up to 25.02 units), where year-on-year variance is expected. This category had seen a negative growth of 60.6% in the previous year. add my warm thanks and congratulations to all of our researchers, funders, collaborators, partners and students who contributed to the excellent accredited research results of 2011, as well as generated the many forms of scholarship that are not counted in the accreditation exercise, but which contribute much to the rich intellectual space that is Rhodes. I also thank all of the administrators who played a critical role in preparing the university’s meticulous audited submission. , A publication of the Rhodes Research Office, compiled and edited by Jaine Roberts and Verna Connan. Design and Layout: Sally Dore.
- Full Text:
- Date Issued: 2011
Risk-based assessment of environmental asbestos contamination in the Northern Cape and North West provinces of South Africa
- Authors: Jones, Robert Ryan
- Date: 2011
- Subjects: Asbestos industry -- Health aspects -- South Africa -- Northern Cape Asbestos industry -- Health aspects -- South Africa -- North West Environmental risk assessment -- South Africa-- Northern Cape Environmental risk assessment -- North West Asbestos -- Toxicology -- South Africa -- Northern Cape Asbestos -- Toxicology -- South Africa -- North West Tailings (Metallurgy) -- Waste disposal -- South Africa -- Northern Cape Tailings (Metallurgy) -- Waste disposal -- South Africa -- North West
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4780 , http://hdl.handle.net/10962/d1012612
- Description: The commercial mining of asbestos occurred in four Provinces of South Africa (Northern Cape, North West, Limpopo and Mpumalanga). It was initiated in the late 1800's and lasted for over a hundred years into the beginning of this century. As a producer of amphibole asbestos, South Africa far outpaced every other country being responsible for 97% of global production. The last crocidolite mine closed in 1996 and chrysotile in 2002. Anecdotal information concerning environmental contamination as a result of the former mining activities and the improper disposal of mine waste tailings has been reported by a variety of authors. Few comprehensive or systematic surveys have been conducted to date to document this issue and very little quantifiable research has been completed on the communities located in close proximity to the former mine sites to determine the extent of contamination. In 2004-2006 communities were surveyed within the Northern Cape and North West Provinces to determine the extent and severity of environmental contamination. This research developed and applied a methodology to select those communities suspected of environmental contamination, a targeted survey methodology, and a protocol for rapid sample laboratory analysis. A total of 41 communities were initially predicted by the model to be suspected for environmental asbestos contamination. Based on the inclusion of local knowledge, a final 36 communities were selected for a screening-level field assessment, 34 of which were found to contain environmental asbestos contamination at rates ranging from 20 to 100% of the surveyed locations. A total of 1 843 samples of soil and building material were collected in the screening level assessment. One community (Ga-Mopedi) was selected as being representative of the total cohort and a more detailed house to house survey was completed. A total of 1 486 samples were collected during the detailed survey. Results of the detailed survey revealed 26.2% of the homes were contaminated with asbestos containing soil and/or building material. A theoretical quantitative cumulative exposure assessment was developed to estimate the disease burden within the study area population of 126,130 individuals within the surveyed communities resulting in a predicted range of 25-52.4 excess deaths per year from lung cancer and mesothelioma due solely to environmental exposures to asbestos pollution.
- Full Text:
- Date Issued: 2011
- Authors: Jones, Robert Ryan
- Date: 2011
- Subjects: Asbestos industry -- Health aspects -- South Africa -- Northern Cape Asbestos industry -- Health aspects -- South Africa -- North West Environmental risk assessment -- South Africa-- Northern Cape Environmental risk assessment -- North West Asbestos -- Toxicology -- South Africa -- Northern Cape Asbestos -- Toxicology -- South Africa -- North West Tailings (Metallurgy) -- Waste disposal -- South Africa -- Northern Cape Tailings (Metallurgy) -- Waste disposal -- South Africa -- North West
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4780 , http://hdl.handle.net/10962/d1012612
- Description: The commercial mining of asbestos occurred in four Provinces of South Africa (Northern Cape, North West, Limpopo and Mpumalanga). It was initiated in the late 1800's and lasted for over a hundred years into the beginning of this century. As a producer of amphibole asbestos, South Africa far outpaced every other country being responsible for 97% of global production. The last crocidolite mine closed in 1996 and chrysotile in 2002. Anecdotal information concerning environmental contamination as a result of the former mining activities and the improper disposal of mine waste tailings has been reported by a variety of authors. Few comprehensive or systematic surveys have been conducted to date to document this issue and very little quantifiable research has been completed on the communities located in close proximity to the former mine sites to determine the extent of contamination. In 2004-2006 communities were surveyed within the Northern Cape and North West Provinces to determine the extent and severity of environmental contamination. This research developed and applied a methodology to select those communities suspected of environmental contamination, a targeted survey methodology, and a protocol for rapid sample laboratory analysis. A total of 41 communities were initially predicted by the model to be suspected for environmental asbestos contamination. Based on the inclusion of local knowledge, a final 36 communities were selected for a screening-level field assessment, 34 of which were found to contain environmental asbestos contamination at rates ranging from 20 to 100% of the surveyed locations. A total of 1 843 samples of soil and building material were collected in the screening level assessment. One community (Ga-Mopedi) was selected as being representative of the total cohort and a more detailed house to house survey was completed. A total of 1 486 samples were collected during the detailed survey. Results of the detailed survey revealed 26.2% of the homes were contaminated with asbestos containing soil and/or building material. A theoretical quantitative cumulative exposure assessment was developed to estimate the disease burden within the study area population of 126,130 individuals within the surveyed communities resulting in a predicted range of 25-52.4 excess deaths per year from lung cancer and mesothelioma due solely to environmental exposures to asbestos pollution.
- Full Text:
- Date Issued: 2011
Sedimentology of plio-pleistocene gravel barrier deposits in the palaeo-Orange River mouth, Namibia : depositional history and diamond mineralisation
- Authors: Spaggiari, Renato Igino
- Date: 2011 , 2013-08-19
- Subjects: Diamond mines and mining -- Namibia Sediments (Geology) -- South Africa and Namibia -- Orange River Estuary Diamond deposits -- Namibia Orange River Estuary (Namibia and South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4927 , http://hdl.handle.net/10962/d1004636
- Description: The largest known marine diamond placer, the Namibian mega-placer, lies along the Atlantic coast of south-western Africa from the Orange River mouth 1,000 km northwards to the Namibian-Angolan border. The most economically viable portion of the Namibian mega-placer (>75 million carats recovered at >95% gem quality) comprises onshore and offshore marine deposits that are developed within ∼100km of the Orange River outfall. For much of the Cainozoic, this long-lived fluvial system has been the main conduit transporting diamonds from kimberlitic and secondary sources in the cratonic hinterland of southern Africa to the Atlantic shelf that has been neutrally buoyant over this period. Highly energetic marine processes, driven in part, by southerly winds with an attendant northward-directed longshore drift, have generated terminal placers that are preserved both onshore and offshore. This study, through detailed field sedimentological and diamond analyses, investigates the development and mineralisation of gravel barrier deposits within the ancestral Orange River mouth area during a major ∼30 m regional transgression ('30 m Package') in the Late Pliocene. At that time, diamond supply from this fluvial conduit was minimal, yet the corresponding onshore marine deposits to the north of the Orange River mouth were significantly diamond enriched, enabling large-scale alluvial diamond mining to take place for over 75 years. Of the entire coastline of south-western Africa, the most complete accumulation of the '30 m Package' is preserved within the palaeo-Orange River mouth as barrier spit and barrier beach deposits. Arranged vertically and laterally in a 16m thick succession, these are deposits of: (1) intertidal beach, (2) lagoon and washover, (3) tidal inlet and spit recurve and (4) storm-dominated subtidal settings. These were parts of larger barrier features, the bulk of which are preserved as highstand deposits that are diamond-bearing with varying, but generally low grades (<13 stones (diamonds) per hundred tons, spht). Intertidal beach and spit recurve deposits have higher economic grades (12-13 spht) due to the energetic sieving and mobile trapping mechanisms associated with their emplacement. In contrast, the less reworked and more sandy subtidal, tidal inlet and washover deposits have un-economic grades (<2 spht). Despite these low grades, the barrier deposits have the largest average stone (diamond) size (1-2 carats/stone, cts/stn) of the entire Namibian mega-placer, given their proximity to the ancestral Orange River outfall. This study demonstrates that barrier shoreline evolution at the fluvial/marine interface was controlled by: (1) a strong and coarse fluvial sediment supply that sustained shoreline growth on a highly energetic coast, (2) accommodation space facilitating sediment preservation and (3) short-duration, high-frequency sea-level cycles superimposed on the∼30 m regional transgression, promoting hierarchal stacking of progradational deposits. During these sea-level fluctuations, diamonds were 'farmed' from older, shelf sequences in the offshore and driven landward to accumulate in '30 m Package' highstand barrier deposits. In spite of the large supply of diamonds, their retention in these deposits was poor due to an incompetent footwall of ancestral Orange River mouth sediment and the inherent cobble-boulder size of the barrier gravels. Thus the principal process controlling diamond entrapment in these barrier deposits was kinetic sieving in a coarse-grained framework. Consequently, at the marine/fluvial interface and down-drift for ∼5 km, larger diamonds (1-2 cts/stn) were retained in low-grade (<2 spht), coarse-gravel barrier shorelines. Smaller diamonds (mostly < I cts/stn) were rejected into the northward-driven littoral sediments and further size-sorted along ∼95 km of Namibian coast to accumulate in finer, high-grade beach placers (> 100 spht) where bedrock footwall promoted such high concentrations. The gravel-dominated palaeo-Orange River mouth is considered to be the ' heart' of the Namibian mega-placer, controlling sediment and diamond supply to the littoral zone further north. Although coarse gravel is retained at the river mouth, the incompetence of this highly energetic setting to trap diamonds renders it sub-economic. This ineffectiveness at the fluvial/marine interface is thus fundamental in enriching the coastal tract farther down-drift and developing highly economic coastal placers along the Atlantic coast of south-western Africa. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2011
- Authors: Spaggiari, Renato Igino
- Date: 2011 , 2013-08-19
- Subjects: Diamond mines and mining -- Namibia Sediments (Geology) -- South Africa and Namibia -- Orange River Estuary Diamond deposits -- Namibia Orange River Estuary (Namibia and South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4927 , http://hdl.handle.net/10962/d1004636
- Description: The largest known marine diamond placer, the Namibian mega-placer, lies along the Atlantic coast of south-western Africa from the Orange River mouth 1,000 km northwards to the Namibian-Angolan border. The most economically viable portion of the Namibian mega-placer (>75 million carats recovered at >95% gem quality) comprises onshore and offshore marine deposits that are developed within ∼100km of the Orange River outfall. For much of the Cainozoic, this long-lived fluvial system has been the main conduit transporting diamonds from kimberlitic and secondary sources in the cratonic hinterland of southern Africa to the Atlantic shelf that has been neutrally buoyant over this period. Highly energetic marine processes, driven in part, by southerly winds with an attendant northward-directed longshore drift, have generated terminal placers that are preserved both onshore and offshore. This study, through detailed field sedimentological and diamond analyses, investigates the development and mineralisation of gravel barrier deposits within the ancestral Orange River mouth area during a major ∼30 m regional transgression ('30 m Package') in the Late Pliocene. At that time, diamond supply from this fluvial conduit was minimal, yet the corresponding onshore marine deposits to the north of the Orange River mouth were significantly diamond enriched, enabling large-scale alluvial diamond mining to take place for over 75 years. Of the entire coastline of south-western Africa, the most complete accumulation of the '30 m Package' is preserved within the palaeo-Orange River mouth as barrier spit and barrier beach deposits. Arranged vertically and laterally in a 16m thick succession, these are deposits of: (1) intertidal beach, (2) lagoon and washover, (3) tidal inlet and spit recurve and (4) storm-dominated subtidal settings. These were parts of larger barrier features, the bulk of which are preserved as highstand deposits that are diamond-bearing with varying, but generally low grades (<13 stones (diamonds) per hundred tons, spht). Intertidal beach and spit recurve deposits have higher economic grades (12-13 spht) due to the energetic sieving and mobile trapping mechanisms associated with their emplacement. In contrast, the less reworked and more sandy subtidal, tidal inlet and washover deposits have un-economic grades (<2 spht). Despite these low grades, the barrier deposits have the largest average stone (diamond) size (1-2 carats/stone, cts/stn) of the entire Namibian mega-placer, given their proximity to the ancestral Orange River outfall. This study demonstrates that barrier shoreline evolution at the fluvial/marine interface was controlled by: (1) a strong and coarse fluvial sediment supply that sustained shoreline growth on a highly energetic coast, (2) accommodation space facilitating sediment preservation and (3) short-duration, high-frequency sea-level cycles superimposed on the∼30 m regional transgression, promoting hierarchal stacking of progradational deposits. During these sea-level fluctuations, diamonds were 'farmed' from older, shelf sequences in the offshore and driven landward to accumulate in '30 m Package' highstand barrier deposits. In spite of the large supply of diamonds, their retention in these deposits was poor due to an incompetent footwall of ancestral Orange River mouth sediment and the inherent cobble-boulder size of the barrier gravels. Thus the principal process controlling diamond entrapment in these barrier deposits was kinetic sieving in a coarse-grained framework. Consequently, at the marine/fluvial interface and down-drift for ∼5 km, larger diamonds (1-2 cts/stn) were retained in low-grade (<2 spht), coarse-gravel barrier shorelines. Smaller diamonds (mostly < I cts/stn) were rejected into the northward-driven littoral sediments and further size-sorted along ∼95 km of Namibian coast to accumulate in finer, high-grade beach placers (> 100 spht) where bedrock footwall promoted such high concentrations. The gravel-dominated palaeo-Orange River mouth is considered to be the ' heart' of the Namibian mega-placer, controlling sediment and diamond supply to the littoral zone further north. Although coarse gravel is retained at the river mouth, the incompetence of this highly energetic setting to trap diamonds renders it sub-economic. This ineffectiveness at the fluvial/marine interface is thus fundamental in enriching the coastal tract farther down-drift and developing highly economic coastal placers along the Atlantic coast of south-western Africa. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2011
Seductive Manoeuvres: an analysis of the use of feminist performance strategies as a means of staging alternative sexualities in two dance theatre works
- Authors: Barnard, Joni
- Date: 2011
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/76823 , vital:30627
- Description: Located within the discipline of Performance Studies, this thesis seeks to validate performance and theatre, specifically dance theatre, as legitimate fields of research and enquiry that can enrich the polemics surrounding discourse, representation, the body and identity. Within this thesis I explore and analyse the creative processes and performance strategies used in two dance theatres works: Acty Tang’s Chaste (2007) and my own work entitled Displayed and Framed (2008) and how these strategies support the staging of alternative sexualities. I argue that the staging of alternative sexualities calls for an alternative approach to the performance strategies utilised in the production of space, the representations of the body and the use of text in both works. Each work offers a particular exploration of gender and sexuality in the attempt to represent alternative identities, alternative bodies and alternative sexualities. In this thesis I identify the endeavour to stage ‘otherness’ as a feminist endeavour and thus identify the performance strategies utilised in each work as feminist performance strategies. Through my analysis I wish to highlight the ways in which a feminist approach can contribute to and enrich both the staging of and understanding of alternative sexualities. In both Chaste (2007) and Displayed and Framed (2008), the choreographers of each work are also performers in their own work in an endeavour to explore and represent their own identity. The analysis of my own work requires that I play the multiple roles of choreographer, performer and researcher. In this analysis I provide accounts of my own experiences, processes and struggles of creating Displayed and Framed (2008) which are analysed in conjunction with my readings of Chaste (2007) and Tang’s personal experiences in creating the work. Thus this thesis explores the value of reflection and self reflectivity in the processes of creating performance.
- Full Text:
- Date Issued: 2011
- Authors: Barnard, Joni
- Date: 2011
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/76823 , vital:30627
- Description: Located within the discipline of Performance Studies, this thesis seeks to validate performance and theatre, specifically dance theatre, as legitimate fields of research and enquiry that can enrich the polemics surrounding discourse, representation, the body and identity. Within this thesis I explore and analyse the creative processes and performance strategies used in two dance theatres works: Acty Tang’s Chaste (2007) and my own work entitled Displayed and Framed (2008) and how these strategies support the staging of alternative sexualities. I argue that the staging of alternative sexualities calls for an alternative approach to the performance strategies utilised in the production of space, the representations of the body and the use of text in both works. Each work offers a particular exploration of gender and sexuality in the attempt to represent alternative identities, alternative bodies and alternative sexualities. In this thesis I identify the endeavour to stage ‘otherness’ as a feminist endeavour and thus identify the performance strategies utilised in each work as feminist performance strategies. Through my analysis I wish to highlight the ways in which a feminist approach can contribute to and enrich both the staging of and understanding of alternative sexualities. In both Chaste (2007) and Displayed and Framed (2008), the choreographers of each work are also performers in their own work in an endeavour to explore and represent their own identity. The analysis of my own work requires that I play the multiple roles of choreographer, performer and researcher. In this analysis I provide accounts of my own experiences, processes and struggles of creating Displayed and Framed (2008) which are analysed in conjunction with my readings of Chaste (2007) and Tang’s personal experiences in creating the work. Thus this thesis explores the value of reflection and self reflectivity in the processes of creating performance.
- Full Text:
- Date Issued: 2011
Sign language in South Africa language planning and policy challenges
- Authors: Ganiso, Mirriam Nosiphiwo
- Date: 2011
- Subjects: Sign language -- Study and teaching -- South Africa Deaf -- Education -- South Africa Deaf -- Means of communication
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3588 , http://hdl.handle.net/10962/d1002163
- Description: This thesis sets out to undertake research into the very important topic of sign language and its usage, particularly in the Western Cape Province of South Africa. Three schools are used in this study. Interviews and questionnaires were used to conduct research with teachers, students and deaf teacher assistants within this context. The analysis of this data is presented in Chapter five of this thesis.
- Full Text:
- Date Issued: 2011
- Authors: Ganiso, Mirriam Nosiphiwo
- Date: 2011
- Subjects: Sign language -- Study and teaching -- South Africa Deaf -- Education -- South Africa Deaf -- Means of communication
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3588 , http://hdl.handle.net/10962/d1002163
- Description: This thesis sets out to undertake research into the very important topic of sign language and its usage, particularly in the Western Cape Province of South Africa. Three schools are used in this study. Interviews and questionnaires were used to conduct research with teachers, students and deaf teacher assistants within this context. The analysis of this data is presented in Chapter five of this thesis.
- Full Text:
- Date Issued: 2011
Solid-phase extraction based sample preparation for the determination of drug and organic pollutant residue
- Authors: Pule, Bellah Oreeditse
- Date: 2011 , 2011-02-08
- Subjects: Food contamination , Drugs -- Analysis , Pharmaceutical chemistry , Extraction (Chemistry) , Sorbents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4406 , http://hdl.handle.net/10962/d1006711 , Food contamination , Drugs -- Analysis , Pharmaceutical chemistry , Extraction (Chemistry) , Sorbents
- Description: This thesis presents solid phase extraction (SPE) methodologies based on mixed-mode polymeric sorbents; a mixed mode strong anion exchanger (Agilent SampliQ SAX) and a mixed mode strong cation exchanger (Agilent SampliQ SCX). Furthermore, dispersive-SPE based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) method was assessed for applicability in the determination of drug residues. The mixed-mode polymeric sorbents were evaluated for the simultaneous fractionation of drugs that exhibit diverse polarities with acidic, basic and neutral functionalities in biological matrices (plasma and urine). The polymeric skeleton of these sorbents entails an exchanger group and therefore provides two retention mechanisms, strong cation or anion exchange retention mechanisms with hydrophobic interactions. It was demonstrated that with a sequential elution protocol for sample clean-up analytes were fractionated into acidic, basic and neutral classes. The SAX was employed for analysis of ketoprofen, naproxen (acidic drugs), nortriptyline (basic) and secobarbital (neutral) from urine sample. The SCX was used for fractionating phenobarbital, p-toluamide (acidic), amphetamine, m-toluidine (basic) and acetaminophen (neutral drug) from plasma sample. QuEChERS method was employed for quantitative determination of 16 polycyclic aromatic hydrocarbons (PAHs) from fish fillets and soil; 9 sulfonamides (SAs) from chicken muscles and acrylamide (AA) in cooking oil. The analyte recoveries ranged from 79.6 - 109% with RSDs ranging from 0.06 - 1.9% at three different fortification levels. Good linearity (r2 > 0.9990) was attained for most analytes. The limits of detection and quantification ranged from 0.03 - 0.84 μg/ml and 0.81 - 1.89 μg/ml respectively for analytes in biological samples. LODs and LOQs for analytes in food and environmental samples ranged from 0.02 to 0.39 and 0.25 to 1.30 ng/g respectively.
- Full Text:
- Date Issued: 2011
- Authors: Pule, Bellah Oreeditse
- Date: 2011 , 2011-02-08
- Subjects: Food contamination , Drugs -- Analysis , Pharmaceutical chemistry , Extraction (Chemistry) , Sorbents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4406 , http://hdl.handle.net/10962/d1006711 , Food contamination , Drugs -- Analysis , Pharmaceutical chemistry , Extraction (Chemistry) , Sorbents
- Description: This thesis presents solid phase extraction (SPE) methodologies based on mixed-mode polymeric sorbents; a mixed mode strong anion exchanger (Agilent SampliQ SAX) and a mixed mode strong cation exchanger (Agilent SampliQ SCX). Furthermore, dispersive-SPE based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) method was assessed for applicability in the determination of drug residues. The mixed-mode polymeric sorbents were evaluated for the simultaneous fractionation of drugs that exhibit diverse polarities with acidic, basic and neutral functionalities in biological matrices (plasma and urine). The polymeric skeleton of these sorbents entails an exchanger group and therefore provides two retention mechanisms, strong cation or anion exchange retention mechanisms with hydrophobic interactions. It was demonstrated that with a sequential elution protocol for sample clean-up analytes were fractionated into acidic, basic and neutral classes. The SAX was employed for analysis of ketoprofen, naproxen (acidic drugs), nortriptyline (basic) and secobarbital (neutral) from urine sample. The SCX was used for fractionating phenobarbital, p-toluamide (acidic), amphetamine, m-toluidine (basic) and acetaminophen (neutral drug) from plasma sample. QuEChERS method was employed for quantitative determination of 16 polycyclic aromatic hydrocarbons (PAHs) from fish fillets and soil; 9 sulfonamides (SAs) from chicken muscles and acrylamide (AA) in cooking oil. The analyte recoveries ranged from 79.6 - 109% with RSDs ranging from 0.06 - 1.9% at three different fortification levels. Good linearity (r2 > 0.9990) was attained for most analytes. The limits of detection and quantification ranged from 0.03 - 0.84 μg/ml and 0.81 - 1.89 μg/ml respectively for analytes in biological samples. LODs and LOQs for analytes in food and environmental samples ranged from 0.02 to 0.39 and 0.25 to 1.30 ng/g respectively.
- Full Text:
- Date Issued: 2011
South African money market volatility, asymmetry and retail interest pass-through
- Authors: Fadiran, Gideon Oluwatobi
- Date: 2011
- Subjects: Money market -- South Africa Interest rates -- South Africa Monetary policy -- South Africa Econometric models Banks and banking -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:993 , http://hdl.handle.net/10962/d1002728
- Description: The purpose of this paper is to examine the interest rate transmission mechanism for South Africa as an emerging economy in a pre-repo and repo system. It explains how the money market rate is transmitted to the retail interest rates both in the long-run and short-run and tests the symmetric and asymmetric interest rate pass-through using the Scholnick (1996) ECM and the Wang and Lee (2009) ECM-EGARCH (1, 1)-M methodology. This permitted the examination of the impact of interest rate volatility, along with the leverage effect. An incomplete pass-through is found in the short-run. From the entire sample period, a symmetric adjustment is found in the deposit rate, which had upward rigidity adjustment, while an asymmetric adjustment is found in the lending rate, with a downward rigidity adjustment. All the adjustments supported the collusive pricing arrangements. According to the conditional variance estimation of the ECM-EGARCH (1, 1), negative volatility impact and leverage effect are present and influential only in the deposit interest rate adjustment process in South Africa.
- Full Text:
- Date Issued: 2011
- Authors: Fadiran, Gideon Oluwatobi
- Date: 2011
- Subjects: Money market -- South Africa Interest rates -- South Africa Monetary policy -- South Africa Econometric models Banks and banking -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:993 , http://hdl.handle.net/10962/d1002728
- Description: The purpose of this paper is to examine the interest rate transmission mechanism for South Africa as an emerging economy in a pre-repo and repo system. It explains how the money market rate is transmitted to the retail interest rates both in the long-run and short-run and tests the symmetric and asymmetric interest rate pass-through using the Scholnick (1996) ECM and the Wang and Lee (2009) ECM-EGARCH (1, 1)-M methodology. This permitted the examination of the impact of interest rate volatility, along with the leverage effect. An incomplete pass-through is found in the short-run. From the entire sample period, a symmetric adjustment is found in the deposit rate, which had upward rigidity adjustment, while an asymmetric adjustment is found in the lending rate, with a downward rigidity adjustment. All the adjustments supported the collusive pricing arrangements. According to the conditional variance estimation of the ECM-EGARCH (1, 1), negative volatility impact and leverage effect are present and influential only in the deposit interest rate adjustment process in South Africa.
- Full Text:
- Date Issued: 2011
SphereZyme (TM) technology for enhanced enzyme immobilisation application in biosensors
- Authors: Molawa, Letshego Gloria
- Date: 2011
- Subjects: Immobilized enzymes , Hydrolases , Hydrolysis , SphereZyme , Biosensors , Proteolytic enzymes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3989 , http://hdl.handle.net/10962/d1004048 , Immobilized enzymes , Hydrolases , Hydrolysis , SphereZyme , Biosensors , Proteolytic enzymes
- Description: Self-immobilisation enzyme technologies, such as SphereZyme™, suffer from the lack of applicability to hydrolyse large substrates. Solid support immobilisation is usually a method of choice, to produce a stable biocatalyst for large substrates hydrolysis in the industry. In order to investigate this limitation, a commercial protease called Alcalase® was chosen as a model enzyme due to its natural activity (hydrolysis of large substrates-proteins). Prior to immobilising through the SphereZyme™ technology, Alcalase® was partially purified through dialysis followed by CM Sepharose™ FF cation exchanger. Sample contaminants, such as salts and stabilisers can inhibit protein crosslinking by reacting with glutaraldehyde. Alcalase® was successfully separated into 3 proteases with the major peak correlating to a positive control run on native PAGE, indicating that it was likely subtilisin Carlsberg. A 16% alkaline protease activity for azo-casein hydrolysis was retained when 5% v/v PEI: 25% v/v glutaraldehyde solution was used as a crosslinking agent in Alcalase® SphereZyme™ production. An increase in activity was also observed for monomeric substrates (PNPA) where the highest was 55%. The highest % activities maintained when 0.33 M EDA: 25% v/v glutaraldehyde solution was initially used as crosslinking agent were 4.5% and 1.6% for monomeric and polymeric substrates, respectively. PEI is a hydrophilic branched polymer with an abundance of amine groups compared to EDA. A comparison study of immobilisation efficiencies of SphereZyme™, Eupergit® and Dendrispheres was also performed for large substrate biocatalysis. The two latter technologies are solid-support immobilisation methods. Dendrispheres reached its maximum loading capacity in the first 5 minute of the one hour binding time. Twenty minutes was chosen as a maximum binding time since there was constant protein maintained on the solid support and no enzyme loss was observed during the 1 hour binding time. PEI at pH 11.5, its native pH, gave the highest immobilisation yield and specific activity over the PEI pH range of 11.5 to 7. SphereZyme™ had the highest ratio for azocasein hydrolysis followed by Dendrispheres and Eupergit®. The SphereZyme™ was also shown to be applicable to biosensors for phenol detection. Different modifications of glassy carbon electrode (GCE) were evaluated as a benchmark for the fabrication of SphereZyme™ modified phenol biosensor. GCE modified with laccase SphereZyme™ entrapped in cellulose membrane was the best modification due to the broad catechol range (<0.950 mM), high correlation coefficient (R2, 0.995) and relative high sensitivity factor (0.305 μA.mM-1). This type of biosensor was also shown to be electroactive at pH 7.0 for which its control, free laccase, lacked electroactivity. From the catalytic constants calculated, GCE modified with laccase SphereZyme™ entrapped in cellulose membrane also gave the highest effectiveness factor (Imax/Km app) of 1.84 μA.mM-1. The modified GCE with Alcalase® SphereZyme™ was relatively more sensitive than GCE modified with free Alcalase®.
- Full Text:
- Date Issued: 2011
- Authors: Molawa, Letshego Gloria
- Date: 2011
- Subjects: Immobilized enzymes , Hydrolases , Hydrolysis , SphereZyme , Biosensors , Proteolytic enzymes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3989 , http://hdl.handle.net/10962/d1004048 , Immobilized enzymes , Hydrolases , Hydrolysis , SphereZyme , Biosensors , Proteolytic enzymes
- Description: Self-immobilisation enzyme technologies, such as SphereZyme™, suffer from the lack of applicability to hydrolyse large substrates. Solid support immobilisation is usually a method of choice, to produce a stable biocatalyst for large substrates hydrolysis in the industry. In order to investigate this limitation, a commercial protease called Alcalase® was chosen as a model enzyme due to its natural activity (hydrolysis of large substrates-proteins). Prior to immobilising through the SphereZyme™ technology, Alcalase® was partially purified through dialysis followed by CM Sepharose™ FF cation exchanger. Sample contaminants, such as salts and stabilisers can inhibit protein crosslinking by reacting with glutaraldehyde. Alcalase® was successfully separated into 3 proteases with the major peak correlating to a positive control run on native PAGE, indicating that it was likely subtilisin Carlsberg. A 16% alkaline protease activity for azo-casein hydrolysis was retained when 5% v/v PEI: 25% v/v glutaraldehyde solution was used as a crosslinking agent in Alcalase® SphereZyme™ production. An increase in activity was also observed for monomeric substrates (PNPA) where the highest was 55%. The highest % activities maintained when 0.33 M EDA: 25% v/v glutaraldehyde solution was initially used as crosslinking agent were 4.5% and 1.6% for monomeric and polymeric substrates, respectively. PEI is a hydrophilic branched polymer with an abundance of amine groups compared to EDA. A comparison study of immobilisation efficiencies of SphereZyme™, Eupergit® and Dendrispheres was also performed for large substrate biocatalysis. The two latter technologies are solid-support immobilisation methods. Dendrispheres reached its maximum loading capacity in the first 5 minute of the one hour binding time. Twenty minutes was chosen as a maximum binding time since there was constant protein maintained on the solid support and no enzyme loss was observed during the 1 hour binding time. PEI at pH 11.5, its native pH, gave the highest immobilisation yield and specific activity over the PEI pH range of 11.5 to 7. SphereZyme™ had the highest ratio for azocasein hydrolysis followed by Dendrispheres and Eupergit®. The SphereZyme™ was also shown to be applicable to biosensors for phenol detection. Different modifications of glassy carbon electrode (GCE) were evaluated as a benchmark for the fabrication of SphereZyme™ modified phenol biosensor. GCE modified with laccase SphereZyme™ entrapped in cellulose membrane was the best modification due to the broad catechol range (<0.950 mM), high correlation coefficient (R2, 0.995) and relative high sensitivity factor (0.305 μA.mM-1). This type of biosensor was also shown to be electroactive at pH 7.0 for which its control, free laccase, lacked electroactivity. From the catalytic constants calculated, GCE modified with laccase SphereZyme™ entrapped in cellulose membrane also gave the highest effectiveness factor (Imax/Km app) of 1.84 μA.mM-1. The modified GCE with Alcalase® SphereZyme™ was relatively more sensitive than GCE modified with free Alcalase®.
- Full Text:
- Date Issued: 2011