Response of mangroves in South Africa to anthropogenic and natural impacts
- Hoppe-Speer, Sabine Clara-Lisa
- Authors: Hoppe-Speer, Sabine Clara-Lisa
- Date: 2012
- Subjects: Mangrove forests , Climatic changes , Forest resilience
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10630 , http://hdl.handle.net/10948/d1012123 , Mangrove forests , Climatic changes , Forest resilience
- Description: The total mangrove area cover in South Africa is 1631.7 ha, with the largest area cover in a few estuaries in the KwaZulu-Natal Province (1391.1 ha) and the remainder recorded in the Eastern Cape Province with 240.6 ha. This represents 0.05 percent of Africa‟s mangrove area cover and although small adds irreplaceable value to the biodiversity of South Africa. Mangroves are threatened by over-utilization through harvesting for firewood and building materials as well as excessive browsing and trampling by livestock. The objective of this study was to investigate the response of mangroves to different stressors from natural change as well as anthropogenic pressures. This was done by identifying pressures, measuring area cover, population structure and environmental parameters such as sediment characteristics. Mangroves in 17 estuaries along the east coast were investigated. Population structure and the area covered by mangroves in 2011/2012 were compared with data from the same area for 1999. Detailed studies were conducted in St. Lucia Estuary to investigate the response of mangroves to reduced tidal flooding; mangrove expansion at a latitudinal limit in a protected area at Nahoon Estuary was studied and the effect of cattle browsing on mangroves was measured at Nxaxo Estuary. The St. Lucia Estuary (28°S; 32°E) represented a unique study site as the mouth has been closed to the sea since 2002 and the mangrove habitats have been non-tidal. St. Lucia Estuary is both a Ramsar and World Heritage site and therefore understanding the response of mangroves to changes in the environment is important. In 2010 sediment characteristics and mangrove population structure were measured at four sites which were chosen to represent different salinity and water level conditions. The site fringing the main channel had the highest density of mangrove seedlings and saplings. The dry site had a lower density of mangroves with mostly only tall adult trees and few saplings. Mangrove tree height and density increased at sites with high sediment moisture and low surface sediment salinity. Few seedlings and saplings were found at sites with dry surface sediment and high salinity. Long term data are needed to assess the influence of mouth closure on recruitment and survival of the mangrove forest at St. Lucia Estuary; however this study has shown that sediment characteristics are unfavourable for mangrove growth at sites now characterized by a lack of tidal flooding. It is not known when exactly the mangroves were planted in Nahoon Estuary (32°S; 27° E), East London, but it is suspected that this was in the early 1970s. Avicennia marina (Forrsk.)Vierh. was planted first, followed a few years later by the planting of Bruguiera gymnorrhiza (L.) Lam. and Rhizophora mucronata (L.) among the larger A. marina trees. Surprisingly the mangrove population appears to be thriving and this study tested the hypothesis that mangroves have expanded and replaced salt marsh over a 33 year period. This study provides important information on mangroves growing at higher latitudes, where they were thought to not occur naturally due to lower annual average temperatures. It further provides insights on future scenarios of possible shifts in vegetation types due to climate change at one of the most southerly distribution sites worldwide. The expansion of mangroves was measured over a 33 year period (1978 - 2011) using past aerial photographs and Esri ArcGIS Desktop 10 software. In addition, field surveys were completed in 2011 to determine the population structure of the present mangrove forest and relate this to environmental conditions. The study showed that mangrove area cover increased linearly at a rate of 0.06 ha-1 expanding over a bare mudflat area, while the salt marsh area cover also increased (0.09 ha-1) but was found to be variable over time. The mangrove area is still small (< 2 ha) and at present no competition between mangroves and salt marsh can be deduced. Instead the area has the ability to maintain high biodiversity and biomass. Avicennia marina was the dominant mangrove species and had high recruitment (seedling density was 33 822 ± 16 364 ha-1) but only a few Bruguiera gymnorrhiza and Rhizophora mucronata individuals were found (< 10 adult trees). The site provides opportunities for studies on mangrove / salt marsh interactions in response to a changing climate at the most southern limit of mangrove distribution in Africa. This research has provided the baseline data, permanent quadrats and tagged trees to be used in future long-term monitoring of population growth and sediment characteristics. At Nxaxo Estuary (32°S; 28°E) the response of mangrove trees (Avicennia marina) to cattle browsing and trampling was investigated by using cattle exclusion plots. Exclusion plots were established by fencing in five 25 m2 quadrats and adjacent to each experimental quadrat a control quadrat (not fenced in, 25 m2) was set-up. Trees were tagged and measured annually from 2010 to 2012. Sediment salinity, pH, moisture, organic content, compaction as well as sediment particle size was also measured in each quadrat. Sediment characteristics did not vary between control and experimental plots but did show changes between the years. The mangrove trees in the cattle exclusion plots grew exponentially over a period of two years. There was a significant increase in mean plant height (5.41 ± 0.53 cm), crown volume (0.54 ± 0.01 m3) and crown diameter (7.09 ± 0.60 cm) from 2010 to 2012. Trees in the control plots had significantly lower growth (p < 0.05). There was a decrease in plant height (-0.07 ± 0.67cm1) and only small increases in crown volume (0.14 ± 0.1 m3) and crown diameter (2.03 ± 2.61 cm). The research showed that browsing on mangroves by cattle stunts growth and causes a shrubby appearance as a result of coppicing. The browsed trees were dwarfed with horizontal spreading of branches and intact foliage close to the ground while the plants in the cattle exclusion plots showed an increase in vertical growth and expansion. In the cattle exclusion plots there was a significantly higher percentage of flowering (67 percent) and fruiting (39 percent) trees in 2012 compared to the control sites where 34 percent of the plants were flowering and 5.4 percent of the plants carried immature propagules. Observations in the field also indicated that cattle had trampled a number of seedlings thus influencing mangrove survival. The study concluded that browsing changes the morphological structure of mangrove trees and reduces growth and seedling establishment. This is an additional stress that the mangroves are exposed to in rural areas where cattle are allowed to roam free. Seventeen permanently open estuaries provide habitat for mangrove forests along the former Transkei coast. This part of the Eastern Cape is mostly undeveloped and difficult to access. Mangrove area cover, species distribution, population structure and health of the mangrove habitat were compared with results from previous studies in 1982 and 1999. The mangrove Bruguiera gymnorrhiza had the densest stands and was widely distributed as it was present in 13 of the 17 estuaries. Avicennia marina was dominant in those estuaries which had the largest area cover of mangroves and was present in 10 estuaries, while Rhizophora mucronata was rare and only present in five estuaries. Anthropogenic and natural impacts were noted within the mangrove habitats in each of these estuaries. Harvesting of mangrove wood, livestock browsing and trampling and footpaths occurred in most of the estuaries (> 70 percent). It was observed that browsing on trees resulted in a clear browse-line and browsing on propagules mainly by goats resulted in reduced seedling establishment in most of the estuaries except those in protected areas. Mangroves had re-established in estuaries where they had been previously lost but mouth closure due to drought and sea storms resulted in the mass die back of mangroves in the Kobonqaba Estuary. There was a total loss of 31.5 ha in mangrove area cover in the last 30 years and this was a total reduction of 10.5 ha (11 percent) for every decade. This is high considering that the present total mangrove area cover is only 240.6 ha for all the Transkei estuaries. In this study it was concluded that the anthropogenic impacts such as livestock browsing and trampling as well as harvesting in these estuaries contributed most to the mangrove degradation as these are continuous pressures occurring over long periods and are expected to increase in future with increasing human population. Natural changes such as sea storms occur less frequently but could result in large scale destruction over shorter periods. Examples of these are mouth closure that result in mangrove mass mortality as well as strong floods which destroy forest by scouring of the banks.
- Full Text:
- Date Issued: 2012
- Authors: Hoppe-Speer, Sabine Clara-Lisa
- Date: 2012
- Subjects: Mangrove forests , Climatic changes , Forest resilience
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10630 , http://hdl.handle.net/10948/d1012123 , Mangrove forests , Climatic changes , Forest resilience
- Description: The total mangrove area cover in South Africa is 1631.7 ha, with the largest area cover in a few estuaries in the KwaZulu-Natal Province (1391.1 ha) and the remainder recorded in the Eastern Cape Province with 240.6 ha. This represents 0.05 percent of Africa‟s mangrove area cover and although small adds irreplaceable value to the biodiversity of South Africa. Mangroves are threatened by over-utilization through harvesting for firewood and building materials as well as excessive browsing and trampling by livestock. The objective of this study was to investigate the response of mangroves to different stressors from natural change as well as anthropogenic pressures. This was done by identifying pressures, measuring area cover, population structure and environmental parameters such as sediment characteristics. Mangroves in 17 estuaries along the east coast were investigated. Population structure and the area covered by mangroves in 2011/2012 were compared with data from the same area for 1999. Detailed studies were conducted in St. Lucia Estuary to investigate the response of mangroves to reduced tidal flooding; mangrove expansion at a latitudinal limit in a protected area at Nahoon Estuary was studied and the effect of cattle browsing on mangroves was measured at Nxaxo Estuary. The St. Lucia Estuary (28°S; 32°E) represented a unique study site as the mouth has been closed to the sea since 2002 and the mangrove habitats have been non-tidal. St. Lucia Estuary is both a Ramsar and World Heritage site and therefore understanding the response of mangroves to changes in the environment is important. In 2010 sediment characteristics and mangrove population structure were measured at four sites which were chosen to represent different salinity and water level conditions. The site fringing the main channel had the highest density of mangrove seedlings and saplings. The dry site had a lower density of mangroves with mostly only tall adult trees and few saplings. Mangrove tree height and density increased at sites with high sediment moisture and low surface sediment salinity. Few seedlings and saplings were found at sites with dry surface sediment and high salinity. Long term data are needed to assess the influence of mouth closure on recruitment and survival of the mangrove forest at St. Lucia Estuary; however this study has shown that sediment characteristics are unfavourable for mangrove growth at sites now characterized by a lack of tidal flooding. It is not known when exactly the mangroves were planted in Nahoon Estuary (32°S; 27° E), East London, but it is suspected that this was in the early 1970s. Avicennia marina (Forrsk.)Vierh. was planted first, followed a few years later by the planting of Bruguiera gymnorrhiza (L.) Lam. and Rhizophora mucronata (L.) among the larger A. marina trees. Surprisingly the mangrove population appears to be thriving and this study tested the hypothesis that mangroves have expanded and replaced salt marsh over a 33 year period. This study provides important information on mangroves growing at higher latitudes, where they were thought to not occur naturally due to lower annual average temperatures. It further provides insights on future scenarios of possible shifts in vegetation types due to climate change at one of the most southerly distribution sites worldwide. The expansion of mangroves was measured over a 33 year period (1978 - 2011) using past aerial photographs and Esri ArcGIS Desktop 10 software. In addition, field surveys were completed in 2011 to determine the population structure of the present mangrove forest and relate this to environmental conditions. The study showed that mangrove area cover increased linearly at a rate of 0.06 ha-1 expanding over a bare mudflat area, while the salt marsh area cover also increased (0.09 ha-1) but was found to be variable over time. The mangrove area is still small (< 2 ha) and at present no competition between mangroves and salt marsh can be deduced. Instead the area has the ability to maintain high biodiversity and biomass. Avicennia marina was the dominant mangrove species and had high recruitment (seedling density was 33 822 ± 16 364 ha-1) but only a few Bruguiera gymnorrhiza and Rhizophora mucronata individuals were found (< 10 adult trees). The site provides opportunities for studies on mangrove / salt marsh interactions in response to a changing climate at the most southern limit of mangrove distribution in Africa. This research has provided the baseline data, permanent quadrats and tagged trees to be used in future long-term monitoring of population growth and sediment characteristics. At Nxaxo Estuary (32°S; 28°E) the response of mangrove trees (Avicennia marina) to cattle browsing and trampling was investigated by using cattle exclusion plots. Exclusion plots were established by fencing in five 25 m2 quadrats and adjacent to each experimental quadrat a control quadrat (not fenced in, 25 m2) was set-up. Trees were tagged and measured annually from 2010 to 2012. Sediment salinity, pH, moisture, organic content, compaction as well as sediment particle size was also measured in each quadrat. Sediment characteristics did not vary between control and experimental plots but did show changes between the years. The mangrove trees in the cattle exclusion plots grew exponentially over a period of two years. There was a significant increase in mean plant height (5.41 ± 0.53 cm), crown volume (0.54 ± 0.01 m3) and crown diameter (7.09 ± 0.60 cm) from 2010 to 2012. Trees in the control plots had significantly lower growth (p < 0.05). There was a decrease in plant height (-0.07 ± 0.67cm1) and only small increases in crown volume (0.14 ± 0.1 m3) and crown diameter (2.03 ± 2.61 cm). The research showed that browsing on mangroves by cattle stunts growth and causes a shrubby appearance as a result of coppicing. The browsed trees were dwarfed with horizontal spreading of branches and intact foliage close to the ground while the plants in the cattle exclusion plots showed an increase in vertical growth and expansion. In the cattle exclusion plots there was a significantly higher percentage of flowering (67 percent) and fruiting (39 percent) trees in 2012 compared to the control sites where 34 percent of the plants were flowering and 5.4 percent of the plants carried immature propagules. Observations in the field also indicated that cattle had trampled a number of seedlings thus influencing mangrove survival. The study concluded that browsing changes the morphological structure of mangrove trees and reduces growth and seedling establishment. This is an additional stress that the mangroves are exposed to in rural areas where cattle are allowed to roam free. Seventeen permanently open estuaries provide habitat for mangrove forests along the former Transkei coast. This part of the Eastern Cape is mostly undeveloped and difficult to access. Mangrove area cover, species distribution, population structure and health of the mangrove habitat were compared with results from previous studies in 1982 and 1999. The mangrove Bruguiera gymnorrhiza had the densest stands and was widely distributed as it was present in 13 of the 17 estuaries. Avicennia marina was dominant in those estuaries which had the largest area cover of mangroves and was present in 10 estuaries, while Rhizophora mucronata was rare and only present in five estuaries. Anthropogenic and natural impacts were noted within the mangrove habitats in each of these estuaries. Harvesting of mangrove wood, livestock browsing and trampling and footpaths occurred in most of the estuaries (> 70 percent). It was observed that browsing on trees resulted in a clear browse-line and browsing on propagules mainly by goats resulted in reduced seedling establishment in most of the estuaries except those in protected areas. Mangroves had re-established in estuaries where they had been previously lost but mouth closure due to drought and sea storms resulted in the mass die back of mangroves in the Kobonqaba Estuary. There was a total loss of 31.5 ha in mangrove area cover in the last 30 years and this was a total reduction of 10.5 ha (11 percent) for every decade. This is high considering that the present total mangrove area cover is only 240.6 ha for all the Transkei estuaries. In this study it was concluded that the anthropogenic impacts such as livestock browsing and trampling as well as harvesting in these estuaries contributed most to the mangrove degradation as these are continuous pressures occurring over long periods and are expected to increase in future with increasing human population. Natural changes such as sea storms occur less frequently but could result in large scale destruction over shorter periods. Examples of these are mouth closure that result in mangrove mass mortality as well as strong floods which destroy forest by scouring of the banks.
- Full Text:
- Date Issued: 2012
Quality of work and work life: understanding the work ethic of medical professionals in selected hospitals in the Eastern Cape region of South Africa
- Authors: Kwizera, Alice Stella
- Date: 2012
- Subjects: Hospitals -- Medical staff -- South Africa -- Eastern Cape Work ethic -- South Africa -- Eastern Cape Medical personnel -- Job satisfaction -- South Africa -- Eastern Cape Protestant work ethic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3323 , http://hdl.handle.net/10962/d1003111
- Description: This thesis reports a study of work ethic values, beliefs and attitudes held by medical professionals in selected hospitals in the Eastern Cape, South Africa. The study was in response to the public outcry about the declining work ethic and poor service delivery in South Africa’s healthcare sector. Scholarly interest in the work ethic and its role in economic development dates back to Max Weber’s classical work, which was the starting point for my study. The German economic sociologist published his seminal essay on The Protestant Ethic and the Spirit of Capitalism in 1904/1905. Since that time, Weber’s ideas on the Protestant work ethic continue to inform and influence studies of the contemporary work ethic, which is thought to have become secularised. My study was informed by data collected in 2009 through a questionnaire survey and personal interviews. A total of 174 doctors and nurses, working in four urban, periurban and rural hospitals near East London, completed a self-administered questionnaire. The questionnaire replicated the Multi-Dimensional Work Ethic Profile (MWEP) developed by Miller, Woehr and Hudspeth in 2001/2002. The instrument examines seven critical dimensions of the work ethic, namely self-reliance, morality, (foregoing) leisure, hard work, centrality of work in life, not wasting time, and delay of gratification. In addition, I conducted personal interviews in the same four hospitals with 41 hospital managers, doctors, nurses, and patients to discuss their understanding of the work ethic and its practical application. The study found that both doctors’ and nurses’ overall work ethic scores on the MWEP scale were above average. Although there was no significant difference between the overall work ethic scores of the two professions, doctors scored significantly higher than nurses on the ‘hard work’ and ‘self reliance’ dimensions of the work ethic scale. In the qualitative study, the doctors’ work ethic was rated much more highly than the nurses’ by their superiors and patients; and the work ethic of nurses in the urban hospitals was rated much lower than that of their rural colleagues. In contradiction to the idea of the secularization of the contemporary work ethic, religiosity and religious beliefs were influential in the endorsement of work ethic principles. In line with the notion that ‘happy’ workers are more productive, job and life satisfaction were found to be strong correlates of the work ethic of medical professionals.
- Full Text:
- Date Issued: 2012
- Authors: Kwizera, Alice Stella
- Date: 2012
- Subjects: Hospitals -- Medical staff -- South Africa -- Eastern Cape Work ethic -- South Africa -- Eastern Cape Medical personnel -- Job satisfaction -- South Africa -- Eastern Cape Protestant work ethic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3323 , http://hdl.handle.net/10962/d1003111
- Description: This thesis reports a study of work ethic values, beliefs and attitudes held by medical professionals in selected hospitals in the Eastern Cape, South Africa. The study was in response to the public outcry about the declining work ethic and poor service delivery in South Africa’s healthcare sector. Scholarly interest in the work ethic and its role in economic development dates back to Max Weber’s classical work, which was the starting point for my study. The German economic sociologist published his seminal essay on The Protestant Ethic and the Spirit of Capitalism in 1904/1905. Since that time, Weber’s ideas on the Protestant work ethic continue to inform and influence studies of the contemporary work ethic, which is thought to have become secularised. My study was informed by data collected in 2009 through a questionnaire survey and personal interviews. A total of 174 doctors and nurses, working in four urban, periurban and rural hospitals near East London, completed a self-administered questionnaire. The questionnaire replicated the Multi-Dimensional Work Ethic Profile (MWEP) developed by Miller, Woehr and Hudspeth in 2001/2002. The instrument examines seven critical dimensions of the work ethic, namely self-reliance, morality, (foregoing) leisure, hard work, centrality of work in life, not wasting time, and delay of gratification. In addition, I conducted personal interviews in the same four hospitals with 41 hospital managers, doctors, nurses, and patients to discuss their understanding of the work ethic and its practical application. The study found that both doctors’ and nurses’ overall work ethic scores on the MWEP scale were above average. Although there was no significant difference between the overall work ethic scores of the two professions, doctors scored significantly higher than nurses on the ‘hard work’ and ‘self reliance’ dimensions of the work ethic scale. In the qualitative study, the doctors’ work ethic was rated much more highly than the nurses’ by their superiors and patients; and the work ethic of nurses in the urban hospitals was rated much lower than that of their rural colleagues. In contradiction to the idea of the secularization of the contemporary work ethic, religiosity and religious beliefs were influential in the endorsement of work ethic principles. In line with the notion that ‘happy’ workers are more productive, job and life satisfaction were found to be strong correlates of the work ethic of medical professionals.
- Full Text:
- Date Issued: 2012
Force of habit the mystical foundations of the narcotic
- Authors: Howell, Simon Peter
- Date: 2012
- Subjects: Drug addiction -- Philosophy -- Research Drug addiction -- Political aspects -- Research Cocaine abuse -- Legal status, laws, etc. -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2784 , http://hdl.handle.net/10962/d1002994
- Description: This thesis aims to investigate and deconstruct the relationship between the narcotic, its narrative, and western modernity. To reveal the relationship, this thesis argues that it is possible to understand the philosophical, political, cultural and ethical dimensions of western modernity through the ulterior lens of the narcotic. As such, this thesis investigates western modernity's relationship to (a) cocaine as a specific narcotic, and (b) the concept of the narcotic with all its attendant connotations of addictions, illegitimacy, transgression, illegality, and so on. Accordingly, the thesis is both interpretive of the historical narrative of the narcotic of cocaine, and generative in its deconstruction of the relationship between western modernity and the concept of the narcotic. The deconstruction of this relationship ultimately reveals both prior narratives not as oppositional, but as supplementary. This has radical consequences for the manner in which we engage with narcotic use and the user - if the narcotic is supplement to the logic of western modernity, at each attempt to expel the use and user of the narcotic, rather then create difference, we self implicate ourselves in that expulsion and distance. To seek a new and more just means of dealing with the concept of the narcotic, and its use, therefore requires a new epistemological framework which can at once contemplate both narratives at the same time. To this end, the thesis suggests the use of critical complexity theory as one such methodological tool, if supplemented by the thoughts and strategies of Derridian deconstruction and Foucauldian discourse analysis.
- Full Text:
- Date Issued: 2012
- Authors: Howell, Simon Peter
- Date: 2012
- Subjects: Drug addiction -- Philosophy -- Research Drug addiction -- Political aspects -- Research Cocaine abuse -- Legal status, laws, etc. -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2784 , http://hdl.handle.net/10962/d1002994
- Description: This thesis aims to investigate and deconstruct the relationship between the narcotic, its narrative, and western modernity. To reveal the relationship, this thesis argues that it is possible to understand the philosophical, political, cultural and ethical dimensions of western modernity through the ulterior lens of the narcotic. As such, this thesis investigates western modernity's relationship to (a) cocaine as a specific narcotic, and (b) the concept of the narcotic with all its attendant connotations of addictions, illegitimacy, transgression, illegality, and so on. Accordingly, the thesis is both interpretive of the historical narrative of the narcotic of cocaine, and generative in its deconstruction of the relationship between western modernity and the concept of the narcotic. The deconstruction of this relationship ultimately reveals both prior narratives not as oppositional, but as supplementary. This has radical consequences for the manner in which we engage with narcotic use and the user - if the narcotic is supplement to the logic of western modernity, at each attempt to expel the use and user of the narcotic, rather then create difference, we self implicate ourselves in that expulsion and distance. To seek a new and more just means of dealing with the concept of the narcotic, and its use, therefore requires a new epistemological framework which can at once contemplate both narratives at the same time. To this end, the thesis suggests the use of critical complexity theory as one such methodological tool, if supplemented by the thoughts and strategies of Derridian deconstruction and Foucauldian discourse analysis.
- Full Text:
- Date Issued: 2012
Decentralised cooperative governance in the South African metropolitan municipalities
- Authors: Zimba, Anthony Andile
- Date: 2012
- Subjects: Community development -- South Africa , Local government -- South Africa , Intergovernmental cooperation -- South Africa , Public administration -- South Africa , Human services -- South Africa , Municipal government -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11427 , http://hdl.handle.net/10353/536 , Community development -- South Africa , Local government -- South Africa , Intergovernmental cooperation -- South Africa , Public administration -- South Africa , Human services -- South Africa , Municipal government -- South Africa
- Description: The study emanates from the constitutional imperatives with regard to the role of local government in community development. The notion of cooperative governance is envisaged in the South African Constitution which stipulates that all spheres of government must adhere to the principles of cooperative government and must conduct their activities within the parameters prescribed by the Constitution. The purpose is to support and strengthen the capacity of the local governments to manage their own affairs and to perform their functions. The basic values and principles governing public administration entail that: it must be broadly representative of the people of South Africa in order to redress the imbalances. The existing gaps in the legislation on decision making power at the local level of the municipality, be it in a ward committee or sub council, have not been adequately addressed in the post 1994 democratic dispensation. It is in this context that this study seeks to address these gaps and obstacles, and contribute to the design and development of a decentralized cooperative governance model, specifically to the six metropolitan municipalities and also provide a basis for further research. The findings of the research could be adapted as a national policy in the empowering of municipalities through the dispersal of democratic power which is an essential ingredient of inclusive governance. Based on a case study of six metropolitan municipalities, the research is intended to contribute to the development of empirically grounded; praxis and practical guideline in decentralized cooperative governance which can be adopted and institutionalized in public administration. It is believed that a study of decentralized cooperative governance adds value in that it seeks to link decentralized power and local development. Rather than civil society organisations being seen as adversarial, a creative partnership with the state in local development is crucial. This political assimilation is critical in the construction of democracy through fusing the substantive values of a political culture with the procedural requisites of democratic accountability. This serves to fragment and disperse political power and maintain a system of checks and balances with regard to the exercise of governmental power. The capacity for innovation, flexibility and change can be enhanced at the local level, and it is a cliché that local decision making is viewed as more democratic in contrast to central, top-down decision-making processes. A syncretistic model for local government based on the political adaptation of political and inclusive decentralisation is outlined.
- Full Text:
- Date Issued: 2012
- Authors: Zimba, Anthony Andile
- Date: 2012
- Subjects: Community development -- South Africa , Local government -- South Africa , Intergovernmental cooperation -- South Africa , Public administration -- South Africa , Human services -- South Africa , Municipal government -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11427 , http://hdl.handle.net/10353/536 , Community development -- South Africa , Local government -- South Africa , Intergovernmental cooperation -- South Africa , Public administration -- South Africa , Human services -- South Africa , Municipal government -- South Africa
- Description: The study emanates from the constitutional imperatives with regard to the role of local government in community development. The notion of cooperative governance is envisaged in the South African Constitution which stipulates that all spheres of government must adhere to the principles of cooperative government and must conduct their activities within the parameters prescribed by the Constitution. The purpose is to support and strengthen the capacity of the local governments to manage their own affairs and to perform their functions. The basic values and principles governing public administration entail that: it must be broadly representative of the people of South Africa in order to redress the imbalances. The existing gaps in the legislation on decision making power at the local level of the municipality, be it in a ward committee or sub council, have not been adequately addressed in the post 1994 democratic dispensation. It is in this context that this study seeks to address these gaps and obstacles, and contribute to the design and development of a decentralized cooperative governance model, specifically to the six metropolitan municipalities and also provide a basis for further research. The findings of the research could be adapted as a national policy in the empowering of municipalities through the dispersal of democratic power which is an essential ingredient of inclusive governance. Based on a case study of six metropolitan municipalities, the research is intended to contribute to the development of empirically grounded; praxis and practical guideline in decentralized cooperative governance which can be adopted and institutionalized in public administration. It is believed that a study of decentralized cooperative governance adds value in that it seeks to link decentralized power and local development. Rather than civil society organisations being seen as adversarial, a creative partnership with the state in local development is crucial. This political assimilation is critical in the construction of democracy through fusing the substantive values of a political culture with the procedural requisites of democratic accountability. This serves to fragment and disperse political power and maintain a system of checks and balances with regard to the exercise of governmental power. The capacity for innovation, flexibility and change can be enhanced at the local level, and it is a cliché that local decision making is viewed as more democratic in contrast to central, top-down decision-making processes. A syncretistic model for local government based on the political adaptation of political and inclusive decentralisation is outlined.
- Full Text:
- Date Issued: 2012
An investigation into challenges facing Further Education Training (FET) leaners in the study of Isixhosa in the Port Elizabeth district
- Authors: Mpofu, Nombulelo Patience
- Date: 2012
- Subjects: Xhosa language -- Study and teaching (Secondary) , Port Elizabeth (South Africa) , Effective teaching
- Language: English
- Type: Thesis , Doctoral , DLitt
- Identifier: vital:11840 , http://hdl.handle.net/10353/d1013389 , Xhosa language -- Study and teaching (Secondary) , Port Elizabeth (South Africa) , Effective teaching
- Description: The essential function of a language is communication. Effective communication takes place when speakers understand each other‟s language. Speakers of different languages these days stay with each other. This kind of setting results into multilingualism. Multilingualism refers to the use or maintenance of more than one language in a certain context. In this regard it may refer to the fact that many languages are spoken in South Africa. It serves as a natural solution to the problem of language contact that is extremely widespread throughout South Africa and the world at large. The recognition of the multilingual nature of South African society by the Constitution of this country , as (Made 2010) puts it, necessitates the creation of tools of implementation and redress, in the form of appropriate language policies. Such language policies are designed to correct the universal tendency to practise monolingualism in multilingual societies which disempowers non-mother tongue speakers of the dominant language, to the detriment of both their rights as citizens and in communicative equity in exercising these rights. Many Black South Africans took employment in the industrial centres through urbanization, where they learnt many languages such as Fanakalo, English, Afrikaans and many other languages in the African continent. This resulted into linguistic heterogeneity. Heterogeneity brings speakers of languages together at different workplaces, schools and even places of abode.
- Full Text:
- Date Issued: 2012
- Authors: Mpofu, Nombulelo Patience
- Date: 2012
- Subjects: Xhosa language -- Study and teaching (Secondary) , Port Elizabeth (South Africa) , Effective teaching
- Language: English
- Type: Thesis , Doctoral , DLitt
- Identifier: vital:11840 , http://hdl.handle.net/10353/d1013389 , Xhosa language -- Study and teaching (Secondary) , Port Elizabeth (South Africa) , Effective teaching
- Description: The essential function of a language is communication. Effective communication takes place when speakers understand each other‟s language. Speakers of different languages these days stay with each other. This kind of setting results into multilingualism. Multilingualism refers to the use or maintenance of more than one language in a certain context. In this regard it may refer to the fact that many languages are spoken in South Africa. It serves as a natural solution to the problem of language contact that is extremely widespread throughout South Africa and the world at large. The recognition of the multilingual nature of South African society by the Constitution of this country , as (Made 2010) puts it, necessitates the creation of tools of implementation and redress, in the form of appropriate language policies. Such language policies are designed to correct the universal tendency to practise monolingualism in multilingual societies which disempowers non-mother tongue speakers of the dominant language, to the detriment of both their rights as citizens and in communicative equity in exercising these rights. Many Black South Africans took employment in the industrial centres through urbanization, where they learnt many languages such as Fanakalo, English, Afrikaans and many other languages in the African continent. This resulted into linguistic heterogeneity. Heterogeneity brings speakers of languages together at different workplaces, schools and even places of abode.
- Full Text:
- Date Issued: 2012
Histopathological changes in male wistar rats maintained on a water-based sutherlandia frutescens extract
- Authors: Wickens, Nicolas John
- Date: 2012
- Subjects: Rats -- Physiology , Rats as laboratory animals
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4742 , vital:20670
- Description: In this study a standardized 46 week chronic drinking water toxicity protocol was used to elucidate the toxic potential of Sutherlandia frutescens (S. frutescens) using histopathologic, morphometric and transmission electron microscopic analysis. The histopathologic changes in the duodenum, heart, kidney, liver, lung, pancreas and spleen of male Wistar rats were evaluated. Fifty-four rats were randomly divided into four groups: Group 1 – Normal diet control (ND control), n=7, Group 2 – Normal diet + plant extract (ND + p), n=9, Group 3 – High fat diet control (HFD control), n=19Group 4 – High fat diet + p (HFD + p), n=19In the high fat group male Wistar rats were fed ±55 g/day of a specialised high fat diet over a 46 week period to induce obesity and an insulin resistant state. The treatment groups (groups 2 and 4) received a dose concentration of a tea extract of the S. frutescens plant in their drinking water daily. This study showed that the consumption of S. frutescens significantly reduces weight gain in male Wistar rats on a chronic high fat diet (p≤0.001 vs. HFD control group). S. frutescens appears to propagate periportal and centrilobular glycogen storage in rat hepatocytes in the experimental groups as exemplified by a significantly (p≤0.0001 vs. control groups) increased incidences of Periodic Acid Schiff (PAS) positive staining S. frutescens also reduced intracellular lipid accumulation as made evident by the significantly lower incidence of epicardial adipose tissue (EAT), hepatic steatosis and pancreatic interstitial fat. Obesity was associated with increased fibrotic lesions such as myocardial perivascular fibrosis, centrilobular hepatic fibrosis and pancreatic periductal fibrosis. Obesity associated hypertension contributed to the widespread and significant increase in the average lesion severity of arterial congestion in all organs in the HFD control group. Pulmonary infection was equally prevalent in all rats. Despite the complex histopathology in all groups, differences in the control groups, such as, the presence of a conservative polymorphonuclear leukocyte (PMNL) infiltration, substantial intra-alveolar oedema and focal arterial wall hypertrophy in the control groups was highly suggestive of Sendai viral infection. However histopathologic evidence, in the treatment groups, suggested chronic recurrent viral infection with superimposed Mycoplasma pulmonis (M. pulmonis) bacterial infection. The impact of advanced suppurative pulmonary infection was widespread and exemplified by increased lesion incidences of spontaneous murine progressive cardiomyopathy (MCP) and spontaneous chronic progressive nephropathy (CPN) among others. In conclusion S. frutescens administered for 46 weeks to male Wistar rats significantly lowered intracellular lipid accumulation and obesity associated myocardial, renal, hepatobiliary, pulmonary and pancreatic histopathology. Moreover, duodenal, cardiovascular, hepatobiliary, pulmonary, renal, pancreatic and splenic tissue did not show histopathologic evidence of direct plant extract associated toxicity or carcinogenicity.
- Full Text:
- Date Issued: 2012
- Authors: Wickens, Nicolas John
- Date: 2012
- Subjects: Rats -- Physiology , Rats as laboratory animals
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4742 , vital:20670
- Description: In this study a standardized 46 week chronic drinking water toxicity protocol was used to elucidate the toxic potential of Sutherlandia frutescens (S. frutescens) using histopathologic, morphometric and transmission electron microscopic analysis. The histopathologic changes in the duodenum, heart, kidney, liver, lung, pancreas and spleen of male Wistar rats were evaluated. Fifty-four rats were randomly divided into four groups: Group 1 – Normal diet control (ND control), n=7, Group 2 – Normal diet + plant extract (ND + p), n=9, Group 3 – High fat diet control (HFD control), n=19Group 4 – High fat diet + p (HFD + p), n=19In the high fat group male Wistar rats were fed ±55 g/day of a specialised high fat diet over a 46 week period to induce obesity and an insulin resistant state. The treatment groups (groups 2 and 4) received a dose concentration of a tea extract of the S. frutescens plant in their drinking water daily. This study showed that the consumption of S. frutescens significantly reduces weight gain in male Wistar rats on a chronic high fat diet (p≤0.001 vs. HFD control group). S. frutescens appears to propagate periportal and centrilobular glycogen storage in rat hepatocytes in the experimental groups as exemplified by a significantly (p≤0.0001 vs. control groups) increased incidences of Periodic Acid Schiff (PAS) positive staining S. frutescens also reduced intracellular lipid accumulation as made evident by the significantly lower incidence of epicardial adipose tissue (EAT), hepatic steatosis and pancreatic interstitial fat. Obesity was associated with increased fibrotic lesions such as myocardial perivascular fibrosis, centrilobular hepatic fibrosis and pancreatic periductal fibrosis. Obesity associated hypertension contributed to the widespread and significant increase in the average lesion severity of arterial congestion in all organs in the HFD control group. Pulmonary infection was equally prevalent in all rats. Despite the complex histopathology in all groups, differences in the control groups, such as, the presence of a conservative polymorphonuclear leukocyte (PMNL) infiltration, substantial intra-alveolar oedema and focal arterial wall hypertrophy in the control groups was highly suggestive of Sendai viral infection. However histopathologic evidence, in the treatment groups, suggested chronic recurrent viral infection with superimposed Mycoplasma pulmonis (M. pulmonis) bacterial infection. The impact of advanced suppurative pulmonary infection was widespread and exemplified by increased lesion incidences of spontaneous murine progressive cardiomyopathy (MCP) and spontaneous chronic progressive nephropathy (CPN) among others. In conclusion S. frutescens administered for 46 weeks to male Wistar rats significantly lowered intracellular lipid accumulation and obesity associated myocardial, renal, hepatobiliary, pulmonary and pancreatic histopathology. Moreover, duodenal, cardiovascular, hepatobiliary, pulmonary, renal, pancreatic and splenic tissue did not show histopathologic evidence of direct plant extract associated toxicity or carcinogenicity.
- Full Text:
- Date Issued: 2012
Synthesis, characterization and antimicrobial activity of copper (II) complexes of some hydroxybenzaldimines and their derivatives
- Authors: Sobola, Abdullahi Owolabi
- Date: 2012
- Subjects: Copper , Schiff bases , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4534 , http://hdl.handle.net/10962/d1016258
- Description: This study focuses on the antimicrobial activity of Cu(II) complexes of some orthohydroxybenzaldimines and its derivatives. Four different categories of Schiff base ligands were prepared by condensing salicylaldehyde, o-vanillin, p-vanillin and vanillin with p- and osubstituted anilines; 1-aminonaphthalene; 2- and 3-aminopyridine; 2- and 3- aminomethylpyridine as well as 2-aminobenzimidazole. The last category was prepared from ophenylenediamine and o-vanillin. The Schiff base ligands have been characterized by a combination of elemental analysis and spectral (¹H- and ¹³C-NMR, UV/Visible, infrared and Raman) data. The existence of strong intramolecular hydrogen bonding in the orthohydoxybenzaldimines was evident from the chemical shift values of the hydroxyl proton in the ¹H-NMR spectra of the Schiff base ligands. The hydroxyl proton resonates at high frequency and thus absorbed far downfield at 13.46-11.83 ppm, reflecting the presence of hydrogen bonding between the hydroxyl proton and the imine nitrogen. In the p-substituted aniline analogues of the Schiff base, a plot of the chemical shift values of the hydroxyl proton against the Hammett's substituent parameters gave a linear correlation between the electronegativities of the substituents and the chemical shift values. The nitro group with the highest electronegativity caused the least deshielding of the hydroxyl proton and thus absorbed upfield compared to the less electronegative substituents such as the CH3 and OCH3 analogues. Likewise, in the solid state infrared spectra of the ligands, the hydroxyl stretching band of the ortho-hydroxyl Schiff base ligands was observed as a very broad band and at much lower frequency, 3100-2100 cm⁻¹, indicating the existence of strong intramolecular hydrogen bonding. In the same vein, ¹H- and ¹³C-NMR spectral data for the Schiff base ligands indicated that the prepared compounds exist in the enol form in aprotic solvent, chloroform. The methine proton appeared as singlet and there was no carbonyl signal in the ¹³C-NMR spectra of the Schiff base ligands. This was supported by the infrared data having no vibrational band attributable to the carbonyl stretching of the keto-form of the Schiff base ligands in solid state. However, the UV/Visible study of the Schiff base ligands in protic solvent, methanol, suggested the existence of some of the Schiff base ligands in keto-enol form. A band at greater than 400 nm was observed in the UV/Visible spectra of the ligands and this has been attributed to the presence of the keto form of orthohydroxyl Schiff base ligands in solution. A plot of the molar absorptivity (ε) of the band at greater than 400 nm against Hammett substituent parameters revealed that the intensity of the bands increased with the electronegativity of the substituents. The Cu(II) complexes of salicylaldehyde, o-vanillin and a few p-vanillin based Schiff base ligands are reported in this work. It was observed that introduction of Cu(II) ions into the ligand system resulted in the hydrolysis of the imine band in few cases. All the isolated complexes have been characterized by elemental analysis, conductivity measurement, infrared and UV/Visible spectral data. The structures of three of the Cu(II) complexes were further confirmed by X-ray single crystal diffraction. The Schiff base ligands either coordinated as neutral base through the imine nitrogen or via the imine nitrogen and the phenolic oxygen atoms. In addition, the benzimidazole-based and ovan-2-pico analogues equally coordinated through the imidazole N-3 nitrogen and the azine nitrogen respectively; thus acted as tridentate. In general, the synthesized Cu(II) complexes fell into seven categories viz: [Cu(LH)Cl(H₂O)]Cl; [Cu(LH)₂Cl₂].xH₂O; [CuL₂]; [Cu₂L₂]; [Cu(LH)Cl(H₂O)]Cl; and [MLCl]. The Cu(II) complexes of the form, M(LH)₂Cl₂.xH₂O were either 1:1 or non-electrolyte in methanol and DMF. The third category, CuL₂, was however, non-electrolyte existing as neutral four coordinate Cu(II) complexes. X-ray single crystal structure of Cu(II) complexes derived from the ammonia-based Schiff bases revealed a square planar geometry for the complexes and this agreed with the planar geometry that has been reported for Cu(II) complexes of N-arylsalicylaldimines of the type studied in this work. The complexes, [Cu₂L₂], resulted from the ortho-hydroxyaniline analogues and were polymeric with the Schiff base ligands coordinating to the Cu(II) ions as tridentate dibasic via the imine nitrogen, phenolic oxygen and the aminophenolic oxygen atoms. Cu(II) complexes prepared from ovan-2-ampy and ovan-2-pico Schiff bases were of the forms [Cu(LH)Cl(H₂O)]Cl and [CuLCl] respectively. The X-ray crystal structure of [Cu(ovan-2- pico)Cl] revealed a four-coordinate square planar geometry for the complex. In the same vein, the o-phenylenediamine complexes were of the form [Cu(L)(H₂O)], with the X-ray crystal structure of [Cu(bis-ovanphen)(H₂O)] revealing a square pyramidal geometry. The Schiff base ligands and the isolated Cu(II) complexes have been evaluated for their antimicrobial activity against three bacterial strains (Escherichia coli ATCC® 8739™*, Staphylococcus aureus subsp. aureus ATCC® 6538™* and Bacillus subtilis subsp. spizizeni ATCC® 6633™*) and one fungal strain, Candida albicans ATCC® 2091™*, using agar disc diffusion and broth dilution techniques. It was observed that the presence of the methoxyl group at the ortho-position of the aldehyde moiety of the Schiff base ligands enhanced the activity of the ligand tremendously and thus the o-vanillin analogues showed the highest potency against the tested organisms. In addition, the hydroxyaniline analogues were equally the most promising of all the substituted aniline based Schiff bases. The o-vanillin analogues of the aminopyridines and aminomethylpyridines also exhibited significant activity against the tested organisms. All the 2-aminobenzimidazole series were active against the tested organisms. It should be noted that E. coli was the least susceptible of all the microorganisms while the highest potency was exhibited against the fungus of choice, Candida albicans. Lastly, chelation of the Schiff base ligands with Cu(II) ions did not have significant influence on the activity of the free ligands.
- Full Text:
- Date Issued: 2012
- Authors: Sobola, Abdullahi Owolabi
- Date: 2012
- Subjects: Copper , Schiff bases , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4534 , http://hdl.handle.net/10962/d1016258
- Description: This study focuses on the antimicrobial activity of Cu(II) complexes of some orthohydroxybenzaldimines and its derivatives. Four different categories of Schiff base ligands were prepared by condensing salicylaldehyde, o-vanillin, p-vanillin and vanillin with p- and osubstituted anilines; 1-aminonaphthalene; 2- and 3-aminopyridine; 2- and 3- aminomethylpyridine as well as 2-aminobenzimidazole. The last category was prepared from ophenylenediamine and o-vanillin. The Schiff base ligands have been characterized by a combination of elemental analysis and spectral (¹H- and ¹³C-NMR, UV/Visible, infrared and Raman) data. The existence of strong intramolecular hydrogen bonding in the orthohydoxybenzaldimines was evident from the chemical shift values of the hydroxyl proton in the ¹H-NMR spectra of the Schiff base ligands. The hydroxyl proton resonates at high frequency and thus absorbed far downfield at 13.46-11.83 ppm, reflecting the presence of hydrogen bonding between the hydroxyl proton and the imine nitrogen. In the p-substituted aniline analogues of the Schiff base, a plot of the chemical shift values of the hydroxyl proton against the Hammett's substituent parameters gave a linear correlation between the electronegativities of the substituents and the chemical shift values. The nitro group with the highest electronegativity caused the least deshielding of the hydroxyl proton and thus absorbed upfield compared to the less electronegative substituents such as the CH3 and OCH3 analogues. Likewise, in the solid state infrared spectra of the ligands, the hydroxyl stretching band of the ortho-hydroxyl Schiff base ligands was observed as a very broad band and at much lower frequency, 3100-2100 cm⁻¹, indicating the existence of strong intramolecular hydrogen bonding. In the same vein, ¹H- and ¹³C-NMR spectral data for the Schiff base ligands indicated that the prepared compounds exist in the enol form in aprotic solvent, chloroform. The methine proton appeared as singlet and there was no carbonyl signal in the ¹³C-NMR spectra of the Schiff base ligands. This was supported by the infrared data having no vibrational band attributable to the carbonyl stretching of the keto-form of the Schiff base ligands in solid state. However, the UV/Visible study of the Schiff base ligands in protic solvent, methanol, suggested the existence of some of the Schiff base ligands in keto-enol form. A band at greater than 400 nm was observed in the UV/Visible spectra of the ligands and this has been attributed to the presence of the keto form of orthohydroxyl Schiff base ligands in solution. A plot of the molar absorptivity (ε) of the band at greater than 400 nm against Hammett substituent parameters revealed that the intensity of the bands increased with the electronegativity of the substituents. The Cu(II) complexes of salicylaldehyde, o-vanillin and a few p-vanillin based Schiff base ligands are reported in this work. It was observed that introduction of Cu(II) ions into the ligand system resulted in the hydrolysis of the imine band in few cases. All the isolated complexes have been characterized by elemental analysis, conductivity measurement, infrared and UV/Visible spectral data. The structures of three of the Cu(II) complexes were further confirmed by X-ray single crystal diffraction. The Schiff base ligands either coordinated as neutral base through the imine nitrogen or via the imine nitrogen and the phenolic oxygen atoms. In addition, the benzimidazole-based and ovan-2-pico analogues equally coordinated through the imidazole N-3 nitrogen and the azine nitrogen respectively; thus acted as tridentate. In general, the synthesized Cu(II) complexes fell into seven categories viz: [Cu(LH)Cl(H₂O)]Cl; [Cu(LH)₂Cl₂].xH₂O; [CuL₂]; [Cu₂L₂]; [Cu(LH)Cl(H₂O)]Cl; and [MLCl]. The Cu(II) complexes of the form, M(LH)₂Cl₂.xH₂O were either 1:1 or non-electrolyte in methanol and DMF. The third category, CuL₂, was however, non-electrolyte existing as neutral four coordinate Cu(II) complexes. X-ray single crystal structure of Cu(II) complexes derived from the ammonia-based Schiff bases revealed a square planar geometry for the complexes and this agreed with the planar geometry that has been reported for Cu(II) complexes of N-arylsalicylaldimines of the type studied in this work. The complexes, [Cu₂L₂], resulted from the ortho-hydroxyaniline analogues and were polymeric with the Schiff base ligands coordinating to the Cu(II) ions as tridentate dibasic via the imine nitrogen, phenolic oxygen and the aminophenolic oxygen atoms. Cu(II) complexes prepared from ovan-2-ampy and ovan-2-pico Schiff bases were of the forms [Cu(LH)Cl(H₂O)]Cl and [CuLCl] respectively. The X-ray crystal structure of [Cu(ovan-2- pico)Cl] revealed a four-coordinate square planar geometry for the complex. In the same vein, the o-phenylenediamine complexes were of the form [Cu(L)(H₂O)], with the X-ray crystal structure of [Cu(bis-ovanphen)(H₂O)] revealing a square pyramidal geometry. The Schiff base ligands and the isolated Cu(II) complexes have been evaluated for their antimicrobial activity against three bacterial strains (Escherichia coli ATCC® 8739™*, Staphylococcus aureus subsp. aureus ATCC® 6538™* and Bacillus subtilis subsp. spizizeni ATCC® 6633™*) and one fungal strain, Candida albicans ATCC® 2091™*, using agar disc diffusion and broth dilution techniques. It was observed that the presence of the methoxyl group at the ortho-position of the aldehyde moiety of the Schiff base ligands enhanced the activity of the ligand tremendously and thus the o-vanillin analogues showed the highest potency against the tested organisms. In addition, the hydroxyaniline analogues were equally the most promising of all the substituted aniline based Schiff bases. The o-vanillin analogues of the aminopyridines and aminomethylpyridines also exhibited significant activity against the tested organisms. All the 2-aminobenzimidazole series were active against the tested organisms. It should be noted that E. coli was the least susceptible of all the microorganisms while the highest potency was exhibited against the fungus of choice, Candida albicans. Lastly, chelation of the Schiff base ligands with Cu(II) ions did not have significant influence on the activity of the free ligands.
- Full Text:
- Date Issued: 2012
A critical assessment of the quality of community home-based care
- Authors: Morton, David Gerard
- Date: 2012
- Subjects: Home care services -- South Africa -- Eastern Cape , Home nursing -- Equipment and supplies , Caregivers -- South Africa -- Eastern Cape , Community health nursing -- South Africa -- Eastern Cape , Home health aides
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:16133 , http://hdl.handle.net/10948/1606 , Home care services -- South Africa -- Eastern Cape , Home nursing -- Equipment and supplies , Caregivers -- South Africa -- Eastern Cape , Community health nursing -- South Africa -- Eastern Cape , Home health aides
- Description: Volunteer home-based caregivers are critical role players in South Africa‘s health care system and in the South African government‘s strategy to fight HIV and AIDS. In order to achieve the aims that the government seeks to attain, it is important that the care and treatment provided to patients receiving community home-based care (CHBC) be of a high quality. While the need for quality care is supported by government and civil society, research indicates that it is not clear whether quality care is indeed being provided and therefore there is a need for research into the quality of CHBC. The research aimed to undertake a critical assessment of CHBC programmes to determine the quality of care provided by volunteer caregivers using social capital theory as a theoretical framework. The study examined the quality of CHBC by analysing the context of CHBC, by investigating the support that volunteer caregivers and their clients receive and by discussing the support that volunteer caregivers and their clients still need. The study used one-on-one in-depth interviews and focus groups to obtain relevant data. The participants included volunteer caregivers, clients and supervisors who took part in the one-on-one interviews. The focus groups consisted of key informants and supervisors respectively. The quantitative data consisted of descriptive statistics which helped describe the participants. The qualitative data was coded and themes and sub-themes were developed. The data was also analysed by an independent coder. The results showed that poverty, and the related problems of poor living conditions and a lack of food security affects the quality CHBC. In addition, unemployment and the problem of stipends also affect quality CHBC. Certain socio-economic factors were also found to lead people to choose to become volunteer caregivers and unemployment was found to be an important driving force behind the choice to undertake volunteer caregiving. Furthermore, the volunteer caregivers in the sample received organisational support from their supervisors and their fellow caregivers or peers. They also received social support from their families and their communities. Regarding the clients of the volunteer caregivers, it was found that they received a number of types of support including psycho- iv social counselling, spiritual counselling and care of a holistic nature. In addition, the study found that there is a need for standardised quality training of volunteer caregivers, which will equip them with multiple skills. It was also found that volunteer caregivers require mentoring and quality supervision in order to be able to provide quality CHBC to their clients. Government has the ability to put the necessary systems and structures in place, such as a scope of practice for volunteers, standardised training and monitoring and evaluation, to enable CHBC and its relevant role players to operate at optimum levels. It also has the authority to make the changes and to enforce rules. Furthermore, it has the ability to unite CHBC organisations and can create the necessary conditions that can lead to increased social capital. Furthermore, the study recommends that two additional dimensions of quality care be added to existing dimensions of quality in health care. The first is the holistic approach to caregiving and the second is social support systems, namely supervisor/mentor and peer support and family and community support. This second dimension is also closely linked to social capital and the networks that make up CHBC.
- Full Text:
- Date Issued: 2012
- Authors: Morton, David Gerard
- Date: 2012
- Subjects: Home care services -- South Africa -- Eastern Cape , Home nursing -- Equipment and supplies , Caregivers -- South Africa -- Eastern Cape , Community health nursing -- South Africa -- Eastern Cape , Home health aides
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:16133 , http://hdl.handle.net/10948/1606 , Home care services -- South Africa -- Eastern Cape , Home nursing -- Equipment and supplies , Caregivers -- South Africa -- Eastern Cape , Community health nursing -- South Africa -- Eastern Cape , Home health aides
- Description: Volunteer home-based caregivers are critical role players in South Africa‘s health care system and in the South African government‘s strategy to fight HIV and AIDS. In order to achieve the aims that the government seeks to attain, it is important that the care and treatment provided to patients receiving community home-based care (CHBC) be of a high quality. While the need for quality care is supported by government and civil society, research indicates that it is not clear whether quality care is indeed being provided and therefore there is a need for research into the quality of CHBC. The research aimed to undertake a critical assessment of CHBC programmes to determine the quality of care provided by volunteer caregivers using social capital theory as a theoretical framework. The study examined the quality of CHBC by analysing the context of CHBC, by investigating the support that volunteer caregivers and their clients receive and by discussing the support that volunteer caregivers and their clients still need. The study used one-on-one in-depth interviews and focus groups to obtain relevant data. The participants included volunteer caregivers, clients and supervisors who took part in the one-on-one interviews. The focus groups consisted of key informants and supervisors respectively. The quantitative data consisted of descriptive statistics which helped describe the participants. The qualitative data was coded and themes and sub-themes were developed. The data was also analysed by an independent coder. The results showed that poverty, and the related problems of poor living conditions and a lack of food security affects the quality CHBC. In addition, unemployment and the problem of stipends also affect quality CHBC. Certain socio-economic factors were also found to lead people to choose to become volunteer caregivers and unemployment was found to be an important driving force behind the choice to undertake volunteer caregiving. Furthermore, the volunteer caregivers in the sample received organisational support from their supervisors and their fellow caregivers or peers. They also received social support from their families and their communities. Regarding the clients of the volunteer caregivers, it was found that they received a number of types of support including psycho- iv social counselling, spiritual counselling and care of a holistic nature. In addition, the study found that there is a need for standardised quality training of volunteer caregivers, which will equip them with multiple skills. It was also found that volunteer caregivers require mentoring and quality supervision in order to be able to provide quality CHBC to their clients. Government has the ability to put the necessary systems and structures in place, such as a scope of practice for volunteers, standardised training and monitoring and evaluation, to enable CHBC and its relevant role players to operate at optimum levels. It also has the authority to make the changes and to enforce rules. Furthermore, it has the ability to unite CHBC organisations and can create the necessary conditions that can lead to increased social capital. Furthermore, the study recommends that two additional dimensions of quality care be added to existing dimensions of quality in health care. The first is the holistic approach to caregiving and the second is social support systems, namely supervisor/mentor and peer support and family and community support. This second dimension is also closely linked to social capital and the networks that make up CHBC.
- Full Text:
- Date Issued: 2012
Transgressive Christian iconography in post-apartheid South African art
- Authors: Von Veh, Karen Elaine
- Date: 2012
- Subjects: Art -- South Africa -- 20th century Art -- South Africa -- 21st century Christian art and symbolism Apartheid in art Art and society -- South Africa -- History -- 20th century Art and society -- South Africa -- History -- 21st century Parody in art
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2424 , http://hdl.handle.net/10962/d1002220
- Description: In this study I propose that transgressive interpretations of Christian iconography provide a valuable strategy for contemporary artists to engage with perceived social inequalities in postapartheid South Africa. Working in light of Michel Foucault’s idea of an “ontology of the present”, I investigate the ways in which religious iconography has been implicated in the regulation of society. Parodic reworking of Christian imagery in the selected examples is investigated as a strategy to expose these controls and offer a critique of mechanisms which produce normative ‘truths’. I also consider how such imagery has been received and the factors accounting for that reception. The study is contextualized by a brief, literary based, historical overview of Christian religious imagery to explain the strength of feeling evinced by religious images. This includes a review of the conflation of religion and state control of the masses, an analysis of the sovereign controls and disciplinary powers that they wield, and an explication of their illustration in religious iconography. I also identify reasons why such imagery may have seemed compelling to artists working in a post-apartheid context. By locating recent works in terms of those made elsewhere or South African examples prior to the period that is my focus, the works discussed are explored in terms of broader orientations in post-apartheid South African art. Artworks that respond to specific Christian iconography are discussed, including Adam and Eve, The Virgin Mary, Christ, and various saints and sinners. The selected artists whose works form the focus of this study are Diane Victor, Christine Dixie, Majak Bredell, Tracey Rose, Wim Botha, Conrad Botes, Johannes Phokela and Lawrence Lemaoana. Through transgressive depictions of Christian icons these artists address current inequalities in society. The content of their works analysed here includes (among others): the construction of both female and male identities; sexual roles, social roles, and racial identity; the social expectations of contemporary motherhood; repressive role models; Afrikaner heritage; political and social change and its effects; colonial power; sacrifice; murder, rape, and violence in South Africa; abuses of power by role models and politicians; rugby; heroism; and patricide. Christian iconography is a useful communicative tool because it has permeated many cultures over centuries, and the meanings it carries are thus accessible to large numbers of people. Religious imagery is often held sacred or is regarded with a degree of reverence, thus ensuring an emotive response when iconoclasm or transgression of any sort is identified. This study argues that by parodying sacred imagery these artists are able to disturb complacent viewing and encourage viewers to engage critically with some of its underlying implications.
- Full Text:
- Date Issued: 2012
- Authors: Von Veh, Karen Elaine
- Date: 2012
- Subjects: Art -- South Africa -- 20th century Art -- South Africa -- 21st century Christian art and symbolism Apartheid in art Art and society -- South Africa -- History -- 20th century Art and society -- South Africa -- History -- 21st century Parody in art
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2424 , http://hdl.handle.net/10962/d1002220
- Description: In this study I propose that transgressive interpretations of Christian iconography provide a valuable strategy for contemporary artists to engage with perceived social inequalities in postapartheid South Africa. Working in light of Michel Foucault’s idea of an “ontology of the present”, I investigate the ways in which religious iconography has been implicated in the regulation of society. Parodic reworking of Christian imagery in the selected examples is investigated as a strategy to expose these controls and offer a critique of mechanisms which produce normative ‘truths’. I also consider how such imagery has been received and the factors accounting for that reception. The study is contextualized by a brief, literary based, historical overview of Christian religious imagery to explain the strength of feeling evinced by religious images. This includes a review of the conflation of religion and state control of the masses, an analysis of the sovereign controls and disciplinary powers that they wield, and an explication of their illustration in religious iconography. I also identify reasons why such imagery may have seemed compelling to artists working in a post-apartheid context. By locating recent works in terms of those made elsewhere or South African examples prior to the period that is my focus, the works discussed are explored in terms of broader orientations in post-apartheid South African art. Artworks that respond to specific Christian iconography are discussed, including Adam and Eve, The Virgin Mary, Christ, and various saints and sinners. The selected artists whose works form the focus of this study are Diane Victor, Christine Dixie, Majak Bredell, Tracey Rose, Wim Botha, Conrad Botes, Johannes Phokela and Lawrence Lemaoana. Through transgressive depictions of Christian icons these artists address current inequalities in society. The content of their works analysed here includes (among others): the construction of both female and male identities; sexual roles, social roles, and racial identity; the social expectations of contemporary motherhood; repressive role models; Afrikaner heritage; political and social change and its effects; colonial power; sacrifice; murder, rape, and violence in South Africa; abuses of power by role models and politicians; rugby; heroism; and patricide. Christian iconography is a useful communicative tool because it has permeated many cultures over centuries, and the meanings it carries are thus accessible to large numbers of people. Religious imagery is often held sacred or is regarded with a degree of reverence, thus ensuring an emotive response when iconoclasm or transgression of any sort is identified. This study argues that by parodying sacred imagery these artists are able to disturb complacent viewing and encourage viewers to engage critically with some of its underlying implications.
- Full Text:
- Date Issued: 2012
An archaelogy of South Africanness: the conditions and fantasies of a post-apartheid festival
- Authors: Truscott, Ross
- Date: 2012
- Subjects: Nationalism -- South Africa -- History -- 20th century , Whites -- Race identity -- South Africa , Afrikaner loyalists , Psychoanalysis , Discourse analysis , Multiculturalism -- South Africa
- Language: English
- Type: Thesis , Doctoral , D Soc Sc (Psych)
- Identifier: vital:11610 , http://hdl.handle.net/10353/539 , Nationalism -- South Africa -- History -- 20th century , Whites -- Race identity -- South Africa , Afrikaner loyalists , Psychoanalysis , Discourse analysis , Multiculturalism -- South Africa
- Description: It has become commonplace in academic studies, particularly those with a critical bent, to view nations as being historical constructs, as being without essence, though not without effects of exclusion and inclusion, of the constitution of the „authentic‟ national subject and the „other of the nation.‟ The critical impetus at work here is to show how a nation is constructed in order to bring into view the knowledge and power relations this construction entails, to show whose interests the construction serves, and whose it does not. This study examines the discursive production, the performative enactment and the spatial emplacement of post-apartheid „South Africanness‟ through a case study of Oppikoppi music festival. Oppikoppi is an annual event that emerged in 1994, on the threshold of the „new South Africa.‟ The festival is attended predominantly by young white Afrikaans-speaking South Africans and is held on a farm in the northernmost province of Limpopo, South Africa, an area notoriously conservative in its racial politics. Yet, curiously, Oppikoppi has been repeatedly referred to, and refers to itself with an almost obsessive regularity and repetitiveness, as a „truly South African‟ event. Indeed, the festival has been promoted, since 1998, as „The Home of South African Music,‟ and in 2009 the site of the festival was unofficially declared a „national monument.‟ Through the employment of concepts drawn from the writings of French philosopher and historian, Michel Foucault – particularly his earlier archaeological works – and from Sigmund Freud – particularly his metapsychological works – this study has posed two broad sets of questions. Firstly, from a Foucauldian perspective, what have been the conditions for the production of „South Africanness‟ at this festival? What have been the requirements, the discursive „rules of the game‟ for whiteness and Afrikanerness to become „South African‟? To what extent does this constitution of the festival as a „South African‟ event preserve older lines of division, difference and oppression? To what extent does this bring about meaningful social change? Secondly, from a psychoanalytic perspective, what are the fantasies constellated in the discourse of the festival as a „South African‟ event? Who, in these fantasies, is constituted as the „other of the post-apartheid nation‟? How has fantasy provided a kind of „hallucinatory gratification,‟ a phantasmatic compensation for, and a means of conserving, the losses of privilege in the new nation? And how has fantasy oriented the festival towards post-apartheid sociality, soliciting identifications with the post-apartheid nation? The overarching argument proposed is that anti-apartheid post-apartheid nation building has cultivated a melancholic loss of apartheid for whites in general and Afrikaners in particular, a loss that cannot be grieved – indeed, a loss that should not be grieved – and, as such, a grief that takes on an unconscious afterlife. Apartheid and the life it enabled – not only racialised privilege, but also a structure of identification and idealisation, of being and having – becomes a loss that is buried in, and by, the injunctions issued to post-apartheid memory and conduct. Without the discursive resources with which to symbolise this loss, disguised repetitions of the past, a neurotic refinding of the lost objects of apartheid, and melancholia are the likely outcomes, each of which engender a set of exclusions and enjoyments that run along old and new lines.
- Full Text:
- Date Issued: 2012
- Authors: Truscott, Ross
- Date: 2012
- Subjects: Nationalism -- South Africa -- History -- 20th century , Whites -- Race identity -- South Africa , Afrikaner loyalists , Psychoanalysis , Discourse analysis , Multiculturalism -- South Africa
- Language: English
- Type: Thesis , Doctoral , D Soc Sc (Psych)
- Identifier: vital:11610 , http://hdl.handle.net/10353/539 , Nationalism -- South Africa -- History -- 20th century , Whites -- Race identity -- South Africa , Afrikaner loyalists , Psychoanalysis , Discourse analysis , Multiculturalism -- South Africa
- Description: It has become commonplace in academic studies, particularly those with a critical bent, to view nations as being historical constructs, as being without essence, though not without effects of exclusion and inclusion, of the constitution of the „authentic‟ national subject and the „other of the nation.‟ The critical impetus at work here is to show how a nation is constructed in order to bring into view the knowledge and power relations this construction entails, to show whose interests the construction serves, and whose it does not. This study examines the discursive production, the performative enactment and the spatial emplacement of post-apartheid „South Africanness‟ through a case study of Oppikoppi music festival. Oppikoppi is an annual event that emerged in 1994, on the threshold of the „new South Africa.‟ The festival is attended predominantly by young white Afrikaans-speaking South Africans and is held on a farm in the northernmost province of Limpopo, South Africa, an area notoriously conservative in its racial politics. Yet, curiously, Oppikoppi has been repeatedly referred to, and refers to itself with an almost obsessive regularity and repetitiveness, as a „truly South African‟ event. Indeed, the festival has been promoted, since 1998, as „The Home of South African Music,‟ and in 2009 the site of the festival was unofficially declared a „national monument.‟ Through the employment of concepts drawn from the writings of French philosopher and historian, Michel Foucault – particularly his earlier archaeological works – and from Sigmund Freud – particularly his metapsychological works – this study has posed two broad sets of questions. Firstly, from a Foucauldian perspective, what have been the conditions for the production of „South Africanness‟ at this festival? What have been the requirements, the discursive „rules of the game‟ for whiteness and Afrikanerness to become „South African‟? To what extent does this constitution of the festival as a „South African‟ event preserve older lines of division, difference and oppression? To what extent does this bring about meaningful social change? Secondly, from a psychoanalytic perspective, what are the fantasies constellated in the discourse of the festival as a „South African‟ event? Who, in these fantasies, is constituted as the „other of the post-apartheid nation‟? How has fantasy provided a kind of „hallucinatory gratification,‟ a phantasmatic compensation for, and a means of conserving, the losses of privilege in the new nation? And how has fantasy oriented the festival towards post-apartheid sociality, soliciting identifications with the post-apartheid nation? The overarching argument proposed is that anti-apartheid post-apartheid nation building has cultivated a melancholic loss of apartheid for whites in general and Afrikaners in particular, a loss that cannot be grieved – indeed, a loss that should not be grieved – and, as such, a grief that takes on an unconscious afterlife. Apartheid and the life it enabled – not only racialised privilege, but also a structure of identification and idealisation, of being and having – becomes a loss that is buried in, and by, the injunctions issued to post-apartheid memory and conduct. Without the discursive resources with which to symbolise this loss, disguised repetitions of the past, a neurotic refinding of the lost objects of apartheid, and melancholia are the likely outcomes, each of which engender a set of exclusions and enjoyments that run along old and new lines.
- Full Text:
- Date Issued: 2012
An evaluation of women participation in housing delivery in the Eastern Cape Province of South Africa: the case of the Mdantsane Township in Buffalo City Municipality (1962–2012)
- Ssekibuule, Henry Jacob Festus
- Authors: Ssekibuule, Henry Jacob Festus
- Date: 2012
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11689 , http://hdl.handle.net/10353/d1013593
- Description: This study, Women Participation in Housing Delivery of the Mdantsane Township Buffalo City Metropolitan Municipality (BCMM) Area is explained in this thesis as a heterogeneous, long lasting, immobile and an essential consumer good that need to be delivered to the homeless. Such a delivery process needs to ensure that the Buffalo City Metropolitan Municipality area remains sustainable. Women's participation in housing delivery in South Africa; the extent of empowerment in the post 1994 era, with specific reference to case studies in Mdantsane Township 1962 -1998, begins with the premise that post-apartheid housing policies, compared to those of the apartheid era, have provided women with greater access to housing. In 1994, the housing backlog was estimated to be about 3.5 million units, with the majority of those in need of shelter, being African women. This backlog was due to past policies that largely excluded women from ownership and access to capital or resources to build formal housing. The changes wrought by the democratic dispensation, such as constitutional provision for gender equality, promised women greater participation in the social, political and economic spheres of the country. The recognition of gender equality and housing as rights protected within the constitution was reinforced by pronouncements in various policy documents, such as the Housing White Paper (HWP) that underlined the need for women's involvement in shelter development. When the Government of National Unity took office in 1994, it inherited a country with severe inequalities in resource distribution and land ownership. In particular, it inherited a housing crisis, which was largely, caused by apartheid legislation and policies. This research focused on the women participation in the housing delivery crisis from 1962 to post-1994, by considering the impact and effect of the constitutional right towards women to have access to adequate housing, especially for those living in intolerable conditions. It does so by utilising a social-scientific approach to the law. This approach acknowledges that the housing right must exist alongside other social phenomena and as a part of everyday life in South Africa. Accordingly, the implementation of the housing right by three local municipalities in the EC was examined.
- Full Text:
- Date Issued: 2012
- Authors: Ssekibuule, Henry Jacob Festus
- Date: 2012
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11689 , http://hdl.handle.net/10353/d1013593
- Description: This study, Women Participation in Housing Delivery of the Mdantsane Township Buffalo City Metropolitan Municipality (BCMM) Area is explained in this thesis as a heterogeneous, long lasting, immobile and an essential consumer good that need to be delivered to the homeless. Such a delivery process needs to ensure that the Buffalo City Metropolitan Municipality area remains sustainable. Women's participation in housing delivery in South Africa; the extent of empowerment in the post 1994 era, with specific reference to case studies in Mdantsane Township 1962 -1998, begins with the premise that post-apartheid housing policies, compared to those of the apartheid era, have provided women with greater access to housing. In 1994, the housing backlog was estimated to be about 3.5 million units, with the majority of those in need of shelter, being African women. This backlog was due to past policies that largely excluded women from ownership and access to capital or resources to build formal housing. The changes wrought by the democratic dispensation, such as constitutional provision for gender equality, promised women greater participation in the social, political and economic spheres of the country. The recognition of gender equality and housing as rights protected within the constitution was reinforced by pronouncements in various policy documents, such as the Housing White Paper (HWP) that underlined the need for women's involvement in shelter development. When the Government of National Unity took office in 1994, it inherited a country with severe inequalities in resource distribution and land ownership. In particular, it inherited a housing crisis, which was largely, caused by apartheid legislation and policies. This research focused on the women participation in the housing delivery crisis from 1962 to post-1994, by considering the impact and effect of the constitutional right towards women to have access to adequate housing, especially for those living in intolerable conditions. It does so by utilising a social-scientific approach to the law. This approach acknowledges that the housing right must exist alongside other social phenomena and as a part of everyday life in South Africa. Accordingly, the implementation of the housing right by three local municipalities in the EC was examined.
- Full Text:
- Date Issued: 2012
A systematic revision of selected genera of afrotropical curtonotidae (Diptera: schizophora: ephydroidea) : a phylogenetic approach
- Authors: Kirk-Spriggs, Ashley H
- Date: 2012
- Subjects: Curtonotidae -- Research Diptera -- Research Flies -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5627 , http://hdl.handle.net/10962/d1004747
- Description: The first comprehensive phylogeny of the family Curtonotidae is presented based on molecular markers and morphology. This enabled assessment of evolutionary relatedness, species radiation and zoogeography. A revised classification of the world fauna of the family, based on the results of this study is outlined. Nomenclatural acts flowing from these analyses include: the recognition three new Afrotropical species of Axinota van der Wulp; four new species of a new genus, Tigrisomyia Kirk-Spriggs; and nineteen new species of Curtonotum (six Madagascan and thirteen African). Ten informal species-groups of Curtonotum are recognised. Identification keys are provided for the Afrotropical species of these genera and errors in previous interpretations and designation of type specimens are resolved. Species distributions are mapped and interpreted and discussion is made of the historical biogeographical significance of these distributions.
- Full Text:
- Date Issued: 2012
- Authors: Kirk-Spriggs, Ashley H
- Date: 2012
- Subjects: Curtonotidae -- Research Diptera -- Research Flies -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5627 , http://hdl.handle.net/10962/d1004747
- Description: The first comprehensive phylogeny of the family Curtonotidae is presented based on molecular markers and morphology. This enabled assessment of evolutionary relatedness, species radiation and zoogeography. A revised classification of the world fauna of the family, based on the results of this study is outlined. Nomenclatural acts flowing from these analyses include: the recognition three new Afrotropical species of Axinota van der Wulp; four new species of a new genus, Tigrisomyia Kirk-Spriggs; and nineteen new species of Curtonotum (six Madagascan and thirteen African). Ten informal species-groups of Curtonotum are recognised. Identification keys are provided for the Afrotropical species of these genera and errors in previous interpretations and designation of type specimens are resolved. Species distributions are mapped and interpreted and discussion is made of the historical biogeographical significance of these distributions.
- Full Text:
- Date Issued: 2012
Mechanistic studies of unusual Miruta-Baylis-Hillman reactions
- Authors: Nyoni, Dubekile
- Date: 2012
- Subjects: Chemical reactions Benzaldehyde Acrylonitrile Methyl acrylate Coumarins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4400 , http://hdl.handle.net/10962/d1006692
- Description: This study has focussed on the application of synthetic, kinetic and exploratory theoretical methods in elucidating the reaction mechanisms of four Morita-Baylis-Hillman (MBH) type reactions, viz, i) the reactions of the disulfide 2,2'-dithiodibenzaldehyde with various activated alkenes in the presence of DBU and Ph₃P, ii) the reactions of chromone-3-carbaldehydes with MVK, iii) the reactions of chromone-2-carbaldehydes with acrylonitrile and iv) with methyl acrylate. Attention has also been given to the origin of the observed regioselectivity in Michaelis-Arbuzov reactions of 3-(halomethyl)coumarins. Cleavage of the sulfur-sulfur bond of aryl and heteroaryl disulfides by the nitrogen nucleophile DBU has been demonstrated, and a dramatic increase in the rate of tandem MBH and disulfide cleavage reactions of 2,2'-dithiodibenzaldehyde with the activated alkenes, MVK, EVK, acrylonitrile, methyl acrylate and tert-butyl acrylate has been achieved through the use of the dual organo-catalyst system, DBU-Ph₃P – an improvement accompanied by an increase in the yields of the isolated products. Detailed NMR-based kinetic studies have been conducted on the DBU-catalysed reactions of 2,2'-dithiodibenzaldehyde with MVK and methyl acrylate, and a theoretical kinetic model has been developed and complementary computational studies using Gaussian 03, at the DFT-B3LYP/6-31G(d) level of theory have provided valuable insights into the mechanism of these complex transformations. Reactions of chromone-3-carbaldehydes with MVK to afford chromone dimers and tricyclic products have been repeated, and a novel, intermediate MBH adduct has been isolated. The mechanisms of the competing pathways have been elucidated by DFT calculations and the development of a detailed theoretical kinetic model has ensued. Unusual transformations in MBH-type reactions of chromone-2-carbaldehydes with acrylonitrile and methyl acrylate have been explored and the structures of the unexpected products have been established using 1- and 2-D NMR, HRMS and X-ray crystallographic techniques. Attention has also been given to the synthesis of 3-(halomethyl)coumarins via the MBH reaction, and their subsequent Michaelis-Arbuzov reactions with triethyl phosphite. An exploratory study of the kinetics of the phosphonation reaction has been undertaken and the regio-selectivity of nucleophilic attack at the 4- and 1'-positions in the 3-chloro- and 3-(iodomethyl)coumarins has been investigated by calculating Mulliken charges, LUMO surfaces and Fukui condensed local softness functions.
- Full Text:
- Date Issued: 2012
- Authors: Nyoni, Dubekile
- Date: 2012
- Subjects: Chemical reactions Benzaldehyde Acrylonitrile Methyl acrylate Coumarins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4400 , http://hdl.handle.net/10962/d1006692
- Description: This study has focussed on the application of synthetic, kinetic and exploratory theoretical methods in elucidating the reaction mechanisms of four Morita-Baylis-Hillman (MBH) type reactions, viz, i) the reactions of the disulfide 2,2'-dithiodibenzaldehyde with various activated alkenes in the presence of DBU and Ph₃P, ii) the reactions of chromone-3-carbaldehydes with MVK, iii) the reactions of chromone-2-carbaldehydes with acrylonitrile and iv) with methyl acrylate. Attention has also been given to the origin of the observed regioselectivity in Michaelis-Arbuzov reactions of 3-(halomethyl)coumarins. Cleavage of the sulfur-sulfur bond of aryl and heteroaryl disulfides by the nitrogen nucleophile DBU has been demonstrated, and a dramatic increase in the rate of tandem MBH and disulfide cleavage reactions of 2,2'-dithiodibenzaldehyde with the activated alkenes, MVK, EVK, acrylonitrile, methyl acrylate and tert-butyl acrylate has been achieved through the use of the dual organo-catalyst system, DBU-Ph₃P – an improvement accompanied by an increase in the yields of the isolated products. Detailed NMR-based kinetic studies have been conducted on the DBU-catalysed reactions of 2,2'-dithiodibenzaldehyde with MVK and methyl acrylate, and a theoretical kinetic model has been developed and complementary computational studies using Gaussian 03, at the DFT-B3LYP/6-31G(d) level of theory have provided valuable insights into the mechanism of these complex transformations. Reactions of chromone-3-carbaldehydes with MVK to afford chromone dimers and tricyclic products have been repeated, and a novel, intermediate MBH adduct has been isolated. The mechanisms of the competing pathways have been elucidated by DFT calculations and the development of a detailed theoretical kinetic model has ensued. Unusual transformations in MBH-type reactions of chromone-2-carbaldehydes with acrylonitrile and methyl acrylate have been explored and the structures of the unexpected products have been established using 1- and 2-D NMR, HRMS and X-ray crystallographic techniques. Attention has also been given to the synthesis of 3-(halomethyl)coumarins via the MBH reaction, and their subsequent Michaelis-Arbuzov reactions with triethyl phosphite. An exploratory study of the kinetics of the phosphonation reaction has been undertaken and the regio-selectivity of nucleophilic attack at the 4- and 1'-positions in the 3-chloro- and 3-(iodomethyl)coumarins has been investigated by calculating Mulliken charges, LUMO surfaces and Fukui condensed local softness functions.
- Full Text:
- Date Issued: 2012
Electrochemical sensing and immunosensing using metallophthalocyanines and biomolecular modified surfaces
- Authors: Mashazi, Philani Nkosinathi
- Date: 2012
- Subjects: Phthalocyanines , Electrochemistry , Electrodes, Enzyme , Measles -- Measurement
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5580 , http://hdl.handle.net/10962/d1018248
- Description: The synthesis of cobalt and manganese phthalocyanine complexes bearing eight hexylthio and four amino substituents was carried out. The formation of thin films of these complexes using different modification methods was also studied. Hexylthio functionalized metallophthalocyanine complexes were immobilized onto gold electrode surfaces using the self-assembly techniques. Surface modifications using cobalt and manganese tetraamino phthalocyanine as polymers, monolayers (onto electrografted surfaces) and as carbon nanotube – metallophthalocyanine conjugates was also carried out. The new method of modifying gold electrodes with metal tetraamino phthalocyanine complexes was investigated. The modified electrode surfaces were studied for their electrocatalytic properties and as potential electrochemical sensors for the detection of hydrogen peroxide (H₂O₂). The limits of detection for the H₂O₂ were of the orders of ~10⁻⁷ M for all the modified electrodes. The modified electrodes gave very good analytical parameters; such as good sensitivity, linearity at studied concentration range and well-defined analytical peaks with increased current densities. The modification methods were reproducible, highly conducting thin films were formed and the modified electrodes were very stable. The design of electrochemical immunosensors for the detection of measles-specific antibodies was also carried out. The modified surface with measles-antigen as sensing element was accomplished using covalent immobilization for an intimate connection of the measles-antigen as a sensing layer onto an electrode surface. Two methods of detecting measles-specific antibodies were investigated and these methods were based on electrochemical impedance, i.e. label-free detection, and voltammetric method using horse-radish peroxidase (HRP) labeled antibody as a reporter. The detection of measles-specific antibodies was accomplished using both these methods. The potential applications of the designed immunosensor were evaluated in real samples (human and newborn calf serum) and the electrodes could detect the antibodies in the complex sample matrix with ease.
- Full Text:
- Date Issued: 2012
- Authors: Mashazi, Philani Nkosinathi
- Date: 2012
- Subjects: Phthalocyanines , Electrochemistry , Electrodes, Enzyme , Measles -- Measurement
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5580 , http://hdl.handle.net/10962/d1018248
- Description: The synthesis of cobalt and manganese phthalocyanine complexes bearing eight hexylthio and four amino substituents was carried out. The formation of thin films of these complexes using different modification methods was also studied. Hexylthio functionalized metallophthalocyanine complexes were immobilized onto gold electrode surfaces using the self-assembly techniques. Surface modifications using cobalt and manganese tetraamino phthalocyanine as polymers, monolayers (onto electrografted surfaces) and as carbon nanotube – metallophthalocyanine conjugates was also carried out. The new method of modifying gold electrodes with metal tetraamino phthalocyanine complexes was investigated. The modified electrode surfaces were studied for their electrocatalytic properties and as potential electrochemical sensors for the detection of hydrogen peroxide (H₂O₂). The limits of detection for the H₂O₂ were of the orders of ~10⁻⁷ M for all the modified electrodes. The modified electrodes gave very good analytical parameters; such as good sensitivity, linearity at studied concentration range and well-defined analytical peaks with increased current densities. The modification methods were reproducible, highly conducting thin films were formed and the modified electrodes were very stable. The design of electrochemical immunosensors for the detection of measles-specific antibodies was also carried out. The modified surface with measles-antigen as sensing element was accomplished using covalent immobilization for an intimate connection of the measles-antigen as a sensing layer onto an electrode surface. Two methods of detecting measles-specific antibodies were investigated and these methods were based on electrochemical impedance, i.e. label-free detection, and voltammetric method using horse-radish peroxidase (HRP) labeled antibody as a reporter. The detection of measles-specific antibodies was accomplished using both these methods. The potential applications of the designed immunosensor were evaluated in real samples (human and newborn calf serum) and the electrodes could detect the antibodies in the complex sample matrix with ease.
- Full Text:
- Date Issued: 2012
An estimate of the cost of electricity outages in Zimbabwe
- Authors: Kaseke, Nyasa
- Date: 2012
- Subjects: Electric power failures -- Zimbabwe , Electric utilities
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: vital:8997 , http://hdl.handle.net/10948/d1011119 , Electric power failures -- Zimbabwe , Electric utilities
- Description: This thesis estimates the cost of electricity outages in Zimbabwe for the year 2009. Much reference is made to government, the power utility - Zimbabwe Electricity Supply Authority (ZESA) and other countries in the Southern African Power Pool (SAPP), also experiencing electricity outages. An electricity outage is a complete loss of power supply to an area. An outage may result from planned or unplanned load shedding or faults. Load shedding is accelerated by power supply shortages. The shortages are experienced during peak demand times. In 2009, Zimbabwe’s peak demand was about 1574MW. ZESA had the capacity to supply 1080MW and imported 100MW (guaranteed from Mozambique), leaving a shortfall of 394MW. This shortfall is worsened by transmission losses (about 108MW) and consumption by ZESA properties (about 200MW) bringng down the supply to customers of about 700MW. The supply shortage is the result of a lack of investment in the power sector by government for expanded generation capacity, incorrect pricing, droughts, internal conflicts, skills flight, government energy sector regulation, vandalism of equipment and under supply of coal to thermal power stations. Consumers in all sectors are experiencing power outage incidences of different duration. The severity of the inconvenience depends on the load shedding time table, preferences of the power utility and arrangements that can be made with the utility. Power outages negatively affect (and result in cost to) the productive sectors (industry, mining and farming) and households. The main objective of the thesis is to estimate the cost of power outages to the sectors. Sub-objectives of the study include: to identify the main features of power crisis in Zimbabwe and government response to it with a regional power generated setting; to formulate a model that clearly identifies the different cost components of power outages in Zimbabwe; to identify appropriate methods by which to estimate these cost components; to estimate the cost of power outages to the productive sectors (mining, agriculture and industrial) and households of Zimbabwe; to critically analyse the credibility of these estimates, and to consider the saving of the costs of outages achieved through increased investment in generating capacity in Zimbabwe. ZESA undertook reforms (institutional and tariff) in order to improve management efficiencies and supply. It was divided into five entities resulting in management and financial improvement, but its reform of tariffs has been stiffled by subsidies and price regulations. ZESA adopted the cost plus rate of return pricing strategy in 2004 but regulation kept the tariff below cost. The regulation is pro-poor in aim but it encourages wasteful consumption. Similar supply shortages are affecting the whole SAPP group. The power pool load shed 758MW in 2009. In Zimbabwe alone load shedding was 315MW. In an attempt to solve the problem, member utilities engage in bilateral contacts and short-term trading through Short Term Energy Markets (STEM). A number of Southern African countries have to load shed - the average frequency being three to five (3-5) times per week for the region. A number of studies have been carried out by different scholars attempting to assess the impact and cost of outages. The general conclusion is that power outages cause significant costs to consumers, both direct and indirect. From a global perspective, the increase in the quality of electricity supplied has fallen behind the increase in quantity demanded, causing an increase of incidence in power outages. An analysis of Sub-Saharan Africa shows that the causes of supply shortages are natural (drought), oil price shocks, conflict and the lack of investment in generation capacity. This generates two outage cost estimates – a direct cost (welfare loss) and indirect cost (backup cost). The sum of these estimates is the total outage cost. The direct cost estimate is based on direct loss incurred during the power outages - lost production, lost materials, and lost time or leisure. In order to derive an estimated direct cost, it is necessary to obtain an accurate respondent self-assessment, which, in turn depends on the keeping of good records of hours of outages and losses incurred during outage times. The estimated indirect cost (backup cost) is derived from the cost of investment in backup sources and running of these sources as a mitigating measure during a power outage. The expected gain from self-generated kWh is assumed to be equal to the expected loss from the marginal kWh electricity not supplied by the utility (the outage). The annualised capital cost of backup source plus the variable cost of generating electricity by the backup source are another element of the cost of power outages. The prices of backup sources were obtained from the two leading retailers, Tendo Power and Ellis Electronics. To the extent that the captive generation includes investment in emergency or optional plant (as part of normal production infrastructure), it may overestimate cost.
- Full Text:
- Date Issued: 2012
- Authors: Kaseke, Nyasa
- Date: 2012
- Subjects: Electric power failures -- Zimbabwe , Electric utilities
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: vital:8997 , http://hdl.handle.net/10948/d1011119 , Electric power failures -- Zimbabwe , Electric utilities
- Description: This thesis estimates the cost of electricity outages in Zimbabwe for the year 2009. Much reference is made to government, the power utility - Zimbabwe Electricity Supply Authority (ZESA) and other countries in the Southern African Power Pool (SAPP), also experiencing electricity outages. An electricity outage is a complete loss of power supply to an area. An outage may result from planned or unplanned load shedding or faults. Load shedding is accelerated by power supply shortages. The shortages are experienced during peak demand times. In 2009, Zimbabwe’s peak demand was about 1574MW. ZESA had the capacity to supply 1080MW and imported 100MW (guaranteed from Mozambique), leaving a shortfall of 394MW. This shortfall is worsened by transmission losses (about 108MW) and consumption by ZESA properties (about 200MW) bringng down the supply to customers of about 700MW. The supply shortage is the result of a lack of investment in the power sector by government for expanded generation capacity, incorrect pricing, droughts, internal conflicts, skills flight, government energy sector regulation, vandalism of equipment and under supply of coal to thermal power stations. Consumers in all sectors are experiencing power outage incidences of different duration. The severity of the inconvenience depends on the load shedding time table, preferences of the power utility and arrangements that can be made with the utility. Power outages negatively affect (and result in cost to) the productive sectors (industry, mining and farming) and households. The main objective of the thesis is to estimate the cost of power outages to the sectors. Sub-objectives of the study include: to identify the main features of power crisis in Zimbabwe and government response to it with a regional power generated setting; to formulate a model that clearly identifies the different cost components of power outages in Zimbabwe; to identify appropriate methods by which to estimate these cost components; to estimate the cost of power outages to the productive sectors (mining, agriculture and industrial) and households of Zimbabwe; to critically analyse the credibility of these estimates, and to consider the saving of the costs of outages achieved through increased investment in generating capacity in Zimbabwe. ZESA undertook reforms (institutional and tariff) in order to improve management efficiencies and supply. It was divided into five entities resulting in management and financial improvement, but its reform of tariffs has been stiffled by subsidies and price regulations. ZESA adopted the cost plus rate of return pricing strategy in 2004 but regulation kept the tariff below cost. The regulation is pro-poor in aim but it encourages wasteful consumption. Similar supply shortages are affecting the whole SAPP group. The power pool load shed 758MW in 2009. In Zimbabwe alone load shedding was 315MW. In an attempt to solve the problem, member utilities engage in bilateral contacts and short-term trading through Short Term Energy Markets (STEM). A number of Southern African countries have to load shed - the average frequency being three to five (3-5) times per week for the region. A number of studies have been carried out by different scholars attempting to assess the impact and cost of outages. The general conclusion is that power outages cause significant costs to consumers, both direct and indirect. From a global perspective, the increase in the quality of electricity supplied has fallen behind the increase in quantity demanded, causing an increase of incidence in power outages. An analysis of Sub-Saharan Africa shows that the causes of supply shortages are natural (drought), oil price shocks, conflict and the lack of investment in generation capacity. This generates two outage cost estimates – a direct cost (welfare loss) and indirect cost (backup cost). The sum of these estimates is the total outage cost. The direct cost estimate is based on direct loss incurred during the power outages - lost production, lost materials, and lost time or leisure. In order to derive an estimated direct cost, it is necessary to obtain an accurate respondent self-assessment, which, in turn depends on the keeping of good records of hours of outages and losses incurred during outage times. The estimated indirect cost (backup cost) is derived from the cost of investment in backup sources and running of these sources as a mitigating measure during a power outage. The expected gain from self-generated kWh is assumed to be equal to the expected loss from the marginal kWh electricity not supplied by the utility (the outage). The annualised capital cost of backup source plus the variable cost of generating electricity by the backup source are another element of the cost of power outages. The prices of backup sources were obtained from the two leading retailers, Tendo Power and Ellis Electronics. To the extent that the captive generation includes investment in emergency or optional plant (as part of normal production infrastructure), it may overestimate cost.
- Full Text:
- Date Issued: 2012
An evaluation of programming assistance tools to support the learning of IT programming: a case study in South African secondary schools
- Authors: Koorsse, Melisa
- Date: 2012
- Subjects: Computer science , Computer literacy , Computer programming
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10472 , http://hdl.handle.net/10948/d1010581 , Computer science , Computer literacy , Computer programming
- Description: Worldwide, there is a decline in interest in the computer science profession and in the subject at secondary school level. Novice programmers struggle to understand introductory programming concepts and this difficulty of learning to program is contributing to the lack of interest in the field of computer science. Information Technology (IT) learners in South African secondary schools are novice programmers, introduced to introductory programming concepts in the subject which also includes topics on hardware and system software, e-communication, social and ethical issues, spreadsheets and databases. The difficulties faced by IT learners are worsened by the lack of suitably qualified teachers, a saturated learning programme that allocates very little time to the understanding of complex programming concepts and limited class time where practical examples can be implemented with the support of the IT teacher. This research proposes that IT learners could be supported by a programming assistance tool (PAT). A PAT is a software program that can be used by novice programmers to learn how to program and/or improve their understanding of programming concepts. PATs use different techniques to assist novice programmers. The main objective of this research was to determine whether the use of a PAT impacted IT learners’ understanding of programming concepts and motivation towards programming. The literature study and feedback from IT learners and teachers were used to identify novice programming difficulties and IT learner programming difficulties, respectively. Selection criteria were derived from the programming difficulties identified. The selection criteria were grouped into three categories, namely, programming concepts, programming knowledge and programming skills. Existing PATs were evaluated using the selection criteria and three PATs, namely, RoboMind, Scratch and B#, were selected as suitable for use by IT learners. RoboMind was adapted in this research study, allowing it to support the Delphi programming language. The three PATs were evaluated by participating IT learners at four schools. The findings of this research provided no conclusive evidence that IT learners who used a PAT had a significantly better understanding of programming concepts and motivation towards programming than learners who did not use a PAT. IT learner feedback was used to identify the strengths and shortcomings of the three PATs and to provide recommendations for the development of PATs specifically to support IT learners. This research study has provided several theoretical and practical contributions, including the research design, selection criteria, adaptations to RoboMind and the evaluation of the three PATs. In addition, IT teachers and learners have been made aware of PATs and the support that can be provided by these PATs. IT teachers have also been provided with a means of selecting PATs applicable to the IT curriculum. All the research contributions have formed the basis for future work, such as improving and extending RoboMind’s functionality and support of programming concepts, the refinement of the selection criteria and, ultimately, the development of a new PAT, specifically designed to support IT learner understanding of programming concepts and motivation towards programming.
- Full Text:
- Date Issued: 2012
- Authors: Koorsse, Melisa
- Date: 2012
- Subjects: Computer science , Computer literacy , Computer programming
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10472 , http://hdl.handle.net/10948/d1010581 , Computer science , Computer literacy , Computer programming
- Description: Worldwide, there is a decline in interest in the computer science profession and in the subject at secondary school level. Novice programmers struggle to understand introductory programming concepts and this difficulty of learning to program is contributing to the lack of interest in the field of computer science. Information Technology (IT) learners in South African secondary schools are novice programmers, introduced to introductory programming concepts in the subject which also includes topics on hardware and system software, e-communication, social and ethical issues, spreadsheets and databases. The difficulties faced by IT learners are worsened by the lack of suitably qualified teachers, a saturated learning programme that allocates very little time to the understanding of complex programming concepts and limited class time where practical examples can be implemented with the support of the IT teacher. This research proposes that IT learners could be supported by a programming assistance tool (PAT). A PAT is a software program that can be used by novice programmers to learn how to program and/or improve their understanding of programming concepts. PATs use different techniques to assist novice programmers. The main objective of this research was to determine whether the use of a PAT impacted IT learners’ understanding of programming concepts and motivation towards programming. The literature study and feedback from IT learners and teachers were used to identify novice programming difficulties and IT learner programming difficulties, respectively. Selection criteria were derived from the programming difficulties identified. The selection criteria were grouped into three categories, namely, programming concepts, programming knowledge and programming skills. Existing PATs were evaluated using the selection criteria and three PATs, namely, RoboMind, Scratch and B#, were selected as suitable for use by IT learners. RoboMind was adapted in this research study, allowing it to support the Delphi programming language. The three PATs were evaluated by participating IT learners at four schools. The findings of this research provided no conclusive evidence that IT learners who used a PAT had a significantly better understanding of programming concepts and motivation towards programming than learners who did not use a PAT. IT learner feedback was used to identify the strengths and shortcomings of the three PATs and to provide recommendations for the development of PATs specifically to support IT learners. This research study has provided several theoretical and practical contributions, including the research design, selection criteria, adaptations to RoboMind and the evaluation of the three PATs. In addition, IT teachers and learners have been made aware of PATs and the support that can be provided by these PATs. IT teachers have also been provided with a means of selecting PATs applicable to the IT curriculum. All the research contributions have formed the basis for future work, such as improving and extending RoboMind’s functionality and support of programming concepts, the refinement of the selection criteria and, ultimately, the development of a new PAT, specifically designed to support IT learner understanding of programming concepts and motivation towards programming.
- Full Text:
- Date Issued: 2012
Characterisation and optimisation of waterjet impact forces and energy parameters during hydroentanglement
- Authors: Moyo, Doice
- Date: 2012
- Subjects: Textile chemistry , Nonwoven fabrics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10453 , http://hdl.handle.net/10948/d1020134
- Description: Hydroentanglement is an important technique of bonding fibres to produce nonwovens using high velocity waterjets as the primary bonding tool. The work reported in this thesis addresses the gap in scientific knowledge and understanding, both theoretical and experimental, related to the impact forces and energy of the waterjets used in the hydroentanglement process. The current study focused on the impact forces and energy involved in, and the optimisation of, the hydroentanglement process. The results of the experimentally measured waterjet impact forces have been used to characterise the waterjets as well as to verify empirically the theoretical models currently available for explaining the mechanics of the hydroentanglement process. Since the process of supplying pressurised waterjets consumes a great deal of energy, the study of energy consumption and efficiency of the system has been critical. A method was proposed and used to determine the coefficients of velocity and water discharge of an industrial machine set-up, helping explain the mechanism of energy transfer during hydroentanglement and to concurrently optimise the process. Furthermore, a response surface experimental design was used to optimise the hydroentanglement of viscose and Polylactic acid (PLA) fibres into nonwovens. The selected Box-Behnken design, with four factors, namely the waterjet force, machine processing speed, input weight and fibre type, was employed to investigate the multivariate process factors and their interactive effects on physical and mechanical properties of nonwovens. Two sets of experiments, the later for validation, were performed to study the energy transfer efficiency. The results of the relative energy transfer to bond the fibrous web showed that it was possible to produce nonwovens using lower input energy without compromising the quality of the products. The optimum waterjet pressure and machine speed used to produce the Abstract nonwoven with the highest tensile strength for the least amount of energy supplied were identified.
- Full Text:
- Date Issued: 2012
- Authors: Moyo, Doice
- Date: 2012
- Subjects: Textile chemistry , Nonwoven fabrics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10453 , http://hdl.handle.net/10948/d1020134
- Description: Hydroentanglement is an important technique of bonding fibres to produce nonwovens using high velocity waterjets as the primary bonding tool. The work reported in this thesis addresses the gap in scientific knowledge and understanding, both theoretical and experimental, related to the impact forces and energy of the waterjets used in the hydroentanglement process. The current study focused on the impact forces and energy involved in, and the optimisation of, the hydroentanglement process. The results of the experimentally measured waterjet impact forces have been used to characterise the waterjets as well as to verify empirically the theoretical models currently available for explaining the mechanics of the hydroentanglement process. Since the process of supplying pressurised waterjets consumes a great deal of energy, the study of energy consumption and efficiency of the system has been critical. A method was proposed and used to determine the coefficients of velocity and water discharge of an industrial machine set-up, helping explain the mechanism of energy transfer during hydroentanglement and to concurrently optimise the process. Furthermore, a response surface experimental design was used to optimise the hydroentanglement of viscose and Polylactic acid (PLA) fibres into nonwovens. The selected Box-Behnken design, with four factors, namely the waterjet force, machine processing speed, input weight and fibre type, was employed to investigate the multivariate process factors and their interactive effects on physical and mechanical properties of nonwovens. Two sets of experiments, the later for validation, were performed to study the energy transfer efficiency. The results of the relative energy transfer to bond the fibrous web showed that it was possible to produce nonwovens using lower input energy without compromising the quality of the products. The optimum waterjet pressure and machine speed used to produce the Abstract nonwoven with the highest tensile strength for the least amount of energy supplied were identified.
- Full Text:
- Date Issued: 2012
Mesozooplankton dynamics in a biogeographical transition zone estuary
- Deyzel, (Shaun) Herklaas Phillipus
- Authors: Deyzel, (Shaun) Herklaas Phillipus
- Date: 2012
- Subjects: Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10687 , http://hdl.handle.net/10948/d1007901 , Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Description: This thesis presents the first intensive community-level investigation of the mesozooplankton from a biogeographical transition zone estuary. The Mgazana Estuary is located along a rural, semi-undeveloped part of South Africa’s east coast, believed to represent a transition zone between the subtropical and warm-temperate biogeographical zones. The research represented in this thesis involves data collected over a five year period between 2002 and 2006, with additional data collection made in 2008. The study focussed on five areas of investigation, the first of which investigated the physico-chemical dynamics of the Mgazana Estuary. The Mgazana Estuary exhibited marked vertical, horizontal and regional structures in the hydrological environment. Prominent vertical and horizontal stratification characterised summer months. A substantial turbidity front was observed in the lower estuary during summer and winter. The upper estuary was marked by considerable variation in multiple variables but especially salinity. These structures appeared to have shifted in position over the horizontal plane, which was attributed to variation in freshwater flow. The second study focused on the spatial dynamics of mesozooplankton in the Mgazana Estuary. The zooplankton was rich and in terms of composition typical of mangrove systems. The Copepoda were dominant, numerically and in terms of taxonomic representation. Calanoids Acartiella natalensis and Pseudodiaptomus hessei characterised middle and upper reaches in summer and mostly upper reaches in winter. On community level, a highly structured assemblage arrangement was observed during summer and winter months. These trends were further scrutinised under the theoretical framework of ecological boundaries. In so doing, an agreeable spatial association emerged between specific assemblages and their environments. These trends were concluded to reflect ecoclinal as well as ecotonal properties, the latter describing interactions over narrow spatial bands of marked changes in turbidity. The third study investigated flooding events as short-lived extreme meteorological events and the influence on zooplankton. Within this regard, second-stage multivariate statistics was used to assess year-to-year variability in assemblage structures on whole-system and regional scales. The impact of two major flooding events that flushed the estuary some days prior to sampling could clearly be elucidated. Flooding emerged as a significant source of inter-annual variability in the zooplankton of the Mgazana Estuary. Second-stage multivariate analysis proved to be an effective analytical strategy for investigating inter-annual variability in species assemblage structures. Results from the preceding study prompted a detailed investigation into the spatio-temporal dynamics of Acartiella natalensis, the most important zooplankton species of the system aimed at elucidating flood responses. Acartiella natalensis showed indication of temporal arrest in association with flooding events in a similar fashion as is observed in seasonal variation trends in estuaries towards its geographical distribution limit south of the study area. It was concluded that A. natalensis was severely affected by floods and the possibility exist for entrainment of entire populations from the estuary during flooding events. The final study tested the hypothesis of post-flood propagation from a resting egg bank in the sediments of the Mgazana Estuary. Preliminary data revealed that numerous eggs were present in the sediments. Nauplii hatched from eggs under laboratory conditions were identified as belonging to the family Acartiidae. The preliminary mode of diapause is presented as a schematic model, emphasising the role of freshwater flow and specific environmental variables. This was the first discovery of resting eggs from a subtropical estuary from South Africa. It is hoped that the findings of this study would give rise to new research initiatives investigating the importance of resting stages in estuarine and coastal Copepoda species and the role such reproductive strategies may play in estuarine functioning.
- Full Text:
- Date Issued: 2012
- Authors: Deyzel, (Shaun) Herklaas Phillipus
- Date: 2012
- Subjects: Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10687 , http://hdl.handle.net/10948/d1007901 , Marine zooplankton -- South Africa , Benthos -- South Africa , Estuarine ecology -- South Africa , Mangrove forests
- Description: This thesis presents the first intensive community-level investigation of the mesozooplankton from a biogeographical transition zone estuary. The Mgazana Estuary is located along a rural, semi-undeveloped part of South Africa’s east coast, believed to represent a transition zone between the subtropical and warm-temperate biogeographical zones. The research represented in this thesis involves data collected over a five year period between 2002 and 2006, with additional data collection made in 2008. The study focussed on five areas of investigation, the first of which investigated the physico-chemical dynamics of the Mgazana Estuary. The Mgazana Estuary exhibited marked vertical, horizontal and regional structures in the hydrological environment. Prominent vertical and horizontal stratification characterised summer months. A substantial turbidity front was observed in the lower estuary during summer and winter. The upper estuary was marked by considerable variation in multiple variables but especially salinity. These structures appeared to have shifted in position over the horizontal plane, which was attributed to variation in freshwater flow. The second study focused on the spatial dynamics of mesozooplankton in the Mgazana Estuary. The zooplankton was rich and in terms of composition typical of mangrove systems. The Copepoda were dominant, numerically and in terms of taxonomic representation. Calanoids Acartiella natalensis and Pseudodiaptomus hessei characterised middle and upper reaches in summer and mostly upper reaches in winter. On community level, a highly structured assemblage arrangement was observed during summer and winter months. These trends were further scrutinised under the theoretical framework of ecological boundaries. In so doing, an agreeable spatial association emerged between specific assemblages and their environments. These trends were concluded to reflect ecoclinal as well as ecotonal properties, the latter describing interactions over narrow spatial bands of marked changes in turbidity. The third study investigated flooding events as short-lived extreme meteorological events and the influence on zooplankton. Within this regard, second-stage multivariate statistics was used to assess year-to-year variability in assemblage structures on whole-system and regional scales. The impact of two major flooding events that flushed the estuary some days prior to sampling could clearly be elucidated. Flooding emerged as a significant source of inter-annual variability in the zooplankton of the Mgazana Estuary. Second-stage multivariate analysis proved to be an effective analytical strategy for investigating inter-annual variability in species assemblage structures. Results from the preceding study prompted a detailed investigation into the spatio-temporal dynamics of Acartiella natalensis, the most important zooplankton species of the system aimed at elucidating flood responses. Acartiella natalensis showed indication of temporal arrest in association with flooding events in a similar fashion as is observed in seasonal variation trends in estuaries towards its geographical distribution limit south of the study area. It was concluded that A. natalensis was severely affected by floods and the possibility exist for entrainment of entire populations from the estuary during flooding events. The final study tested the hypothesis of post-flood propagation from a resting egg bank in the sediments of the Mgazana Estuary. Preliminary data revealed that numerous eggs were present in the sediments. Nauplii hatched from eggs under laboratory conditions were identified as belonging to the family Acartiidae. The preliminary mode of diapause is presented as a schematic model, emphasising the role of freshwater flow and specific environmental variables. This was the first discovery of resting eggs from a subtropical estuary from South Africa. It is hoped that the findings of this study would give rise to new research initiatives investigating the importance of resting stages in estuarine and coastal Copepoda species and the role such reproductive strategies may play in estuarine functioning.
- Full Text:
- Date Issued: 2012
A comparative study of the language, mathematics and science literacy knowledge and skills of grade 9 learners in secondary schools in Port Elizabeth
- Authors: Arnolds, Keith Victor
- Date: 2012
- Subjects: Educational tests and measurements -- South Africa -- Port Elizabeth , Comparative education , Language and languages -- Study and teaching -- South Africa -- Port Elizabeth , Mathematics -- Study and teaching -- South Africa -- Port Elizabeth , Science -- Study and teaching -- South Africa -- Port Elizabeth , Education, Secondary -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9566 , http://hdl.handle.net/10948/d1016062
- Description: In South Africa, on-going concerns surrounding the development of learners’ literacy, mathematics and science skills are evident and drive various research studies in this field. International studies and assessments, such as the Trends in International Mathematics and Science Study (TIMSS) and the Progress in International Reading Literacy Study (PIRLS) show major differences in the proficiency levels of learners in South Africa in comparison with their international counter parts. To date, however, the more comprehensive international standardised assessment called the Programme for International Student Assessment (PISA), has not been administered in South Africa. The main aim of this research study was to investigate and scientifically explore the real situation in terms of language, mathematics and science literacy knowledge and skills of Grade 9 learners in South Africa and to draw a comparison between Grade 9 learners from secondary schools in the Port Elizabeth district in South Africa and their international counterparts, using the PISA standardised international assessment. In addition, the aim of the study was to determine the actual language, mathematics and science literacy skills and knowledge acquired by participants in this study. Quantitative data collection was done by administering a modified version of the Program for International Student Assessment (PISA) to learners from eight schools in Port Elizabeth, supplemented with questionnaires completed by participating learners and school principals. Findings revealed that the South African learners sampled, ranked in the bottom percentile of participating countries in reading, mathematics and science. The study also exposed the glaring inequalities still prevalent in South African education today, 17 years into democracy. The implications point to a serious investigation into the societal and political factors responsible for the discrepancies in the South African educational system at present.
- Full Text:
- Date Issued: 2012
- Authors: Arnolds, Keith Victor
- Date: 2012
- Subjects: Educational tests and measurements -- South Africa -- Port Elizabeth , Comparative education , Language and languages -- Study and teaching -- South Africa -- Port Elizabeth , Mathematics -- Study and teaching -- South Africa -- Port Elizabeth , Science -- Study and teaching -- South Africa -- Port Elizabeth , Education, Secondary -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9566 , http://hdl.handle.net/10948/d1016062
- Description: In South Africa, on-going concerns surrounding the development of learners’ literacy, mathematics and science skills are evident and drive various research studies in this field. International studies and assessments, such as the Trends in International Mathematics and Science Study (TIMSS) and the Progress in International Reading Literacy Study (PIRLS) show major differences in the proficiency levels of learners in South Africa in comparison with their international counter parts. To date, however, the more comprehensive international standardised assessment called the Programme for International Student Assessment (PISA), has not been administered in South Africa. The main aim of this research study was to investigate and scientifically explore the real situation in terms of language, mathematics and science literacy knowledge and skills of Grade 9 learners in South Africa and to draw a comparison between Grade 9 learners from secondary schools in the Port Elizabeth district in South Africa and their international counterparts, using the PISA standardised international assessment. In addition, the aim of the study was to determine the actual language, mathematics and science literacy skills and knowledge acquired by participants in this study. Quantitative data collection was done by administering a modified version of the Program for International Student Assessment (PISA) to learners from eight schools in Port Elizabeth, supplemented with questionnaires completed by participating learners and school principals. Findings revealed that the South African learners sampled, ranked in the bottom percentile of participating countries in reading, mathematics and science. The study also exposed the glaring inequalities still prevalent in South African education today, 17 years into democracy. The implications point to a serious investigation into the societal and political factors responsible for the discrepancies in the South African educational system at present.
- Full Text:
- Date Issued: 2012
Exploiting the adaptability of recent information and communication technology to improve the site management process
- Ozumba, Aghaegbuna Obinna Uche
- Authors: Ozumba, Aghaegbuna Obinna Uche
- Date: 2012
- Subjects: Construction industry -- Information technology , Construction industry -- Materials management , Information technology -- Management.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9705 , http://hdl.handle.net/10948/d1019811
- Description: Construction is a big role player in every economy, and the Site Management Process (SMP) occupies a strategic position in the construction process. Despite existence of appreciable research, technology diffusion in the construction industry is slow. Information and Communication Technology (ICT) implementation processes and products have not adequately and beneficially exploited ICT for improvement of the SMP. This is especially true in developing countries. Without increase in utilisation of ICT, potential benefits for the SMP remain untapped. The aim of the thesis was to ascertain the levels of utilisation of recent ICT developments for the SMP, and thereby gauge the benefits or lack thereof. The theoretical concept of the research is based on the technology transfer sub-concept of adaptation. A fundamentally positivistic view, with principles of objectivist approach was used for the enquiry. The approach included an extensive literature review, and a multi-stage investigation strategy, set in South Africa. Theory reviewed was in the main disciplines of construction science and technology, computer science and technology, and management science. Investigations involved case studies of construction sites, a global ICT survey, a national practitioner survey, and analysis of ICT products. Findings from literature assert the appreciable potential utility in recent ICT, thereby substantiating the adaptability of recent ICT. In addition ICT adoption in the SMP is inadequate and inexpedient, falling short of potential benefits for construction, both generally and in the local context. Furthermore there are challenges to ICT adoption, which could vary according to context. Field research results also point to underutilisation of innovations located in recent ICT. The main challenges in this regard include inadequate knowledge of potential utility of recent ICT, and lack of relevant support and effective approaches to technology integration, in the SMP. Moreover exploitation of the adaptability of recent ICT in the local SMP does not go beyond basic adoption. As such most diffusion occurs only for items requiring an adaptation of usage context or area of application. The results strongly indicate minimal innovativeness in this regard. Frameworks for possible adaptations of existing technologies were also derived, while propositions are made for approaches to improve the utility of recent ICT in the SMP. Through a customised approach, the thesis establishes foundational understanding towards a generic framework for adapting potential utility in ICT to uses in construction, especially in the SMP. Thus the research contributes strategic information to the fledgling CICT body of knowledge, especially in the local context.
- Full Text:
- Date Issued: 2012
- Authors: Ozumba, Aghaegbuna Obinna Uche
- Date: 2012
- Subjects: Construction industry -- Information technology , Construction industry -- Materials management , Information technology -- Management.
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9705 , http://hdl.handle.net/10948/d1019811
- Description: Construction is a big role player in every economy, and the Site Management Process (SMP) occupies a strategic position in the construction process. Despite existence of appreciable research, technology diffusion in the construction industry is slow. Information and Communication Technology (ICT) implementation processes and products have not adequately and beneficially exploited ICT for improvement of the SMP. This is especially true in developing countries. Without increase in utilisation of ICT, potential benefits for the SMP remain untapped. The aim of the thesis was to ascertain the levels of utilisation of recent ICT developments for the SMP, and thereby gauge the benefits or lack thereof. The theoretical concept of the research is based on the technology transfer sub-concept of adaptation. A fundamentally positivistic view, with principles of objectivist approach was used for the enquiry. The approach included an extensive literature review, and a multi-stage investigation strategy, set in South Africa. Theory reviewed was in the main disciplines of construction science and technology, computer science and technology, and management science. Investigations involved case studies of construction sites, a global ICT survey, a national practitioner survey, and analysis of ICT products. Findings from literature assert the appreciable potential utility in recent ICT, thereby substantiating the adaptability of recent ICT. In addition ICT adoption in the SMP is inadequate and inexpedient, falling short of potential benefits for construction, both generally and in the local context. Furthermore there are challenges to ICT adoption, which could vary according to context. Field research results also point to underutilisation of innovations located in recent ICT. The main challenges in this regard include inadequate knowledge of potential utility of recent ICT, and lack of relevant support and effective approaches to technology integration, in the SMP. Moreover exploitation of the adaptability of recent ICT in the local SMP does not go beyond basic adoption. As such most diffusion occurs only for items requiring an adaptation of usage context or area of application. The results strongly indicate minimal innovativeness in this regard. Frameworks for possible adaptations of existing technologies were also derived, while propositions are made for approaches to improve the utility of recent ICT in the SMP. Through a customised approach, the thesis establishes foundational understanding towards a generic framework for adapting potential utility in ICT to uses in construction, especially in the SMP. Thus the research contributes strategic information to the fledgling CICT body of knowledge, especially in the local context.
- Full Text:
- Date Issued: 2012