Movement patterns, stock delineation and conservation of an overexploited fishery species, Lithognathus Lithognathus (Pisces: Sparidae)
- Authors: Bennett, Rhett Hamilton
- Date: 2012
- Subjects: Reef fishes -- Behavior , Endangered species -- South Africa , Fish stock assessment -- South Africa , Fishery management -- South Africa , Fish communities -- South Africa , Sparidae , Lithognathus , Lithognathus -- Growth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5374 , http://hdl.handle.net/10962/d1015709
- Description: White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.
- Full Text:
- Date Issued: 2012
- Authors: Bennett, Rhett Hamilton
- Date: 2012
- Subjects: Reef fishes -- Behavior , Endangered species -- South Africa , Fish stock assessment -- South Africa , Fishery management -- South Africa , Fish communities -- South Africa , Sparidae , Lithognathus , Lithognathus -- Growth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5374 , http://hdl.handle.net/10962/d1015709
- Description: White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.
- Full Text:
- Date Issued: 2012
Management perceptions regarding skills shortages in gold mines
- Authors: Xingwana, Lumkwana
- Date: 2012
- Subjects: Labor supply--South Africa , Professional employees--South Africa , Occupational training--South Africa , Gold mines and mining--South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9279 , http://hdl.handle.net/10948/d1007959 , Labor supply--South Africa , Professional employees--South Africa , Occupational training--South Africa , Gold mines and mining--South Africa
- Description: The skills shortages in mining and mineral sector had existed for a decade and had a widespread effect on South Africa economy. It affects the level of economic productivity and reduces the country’s capacity to develop a knowledge society. This, in turn, affects the country’s functioning in the global economy. Despite the sector’s best efforts, the shortages continue to grow and threaten the delivery of projects and growth plans. Some researchers contend with the view that the persistence of skills shortages in mining and mineral sector is largely due to entrenched attitudes among both the industry and the community. They claim that employers have the means to change the educational profile of the subsectors by appointing recruits with higher levels of schooling. However, owing to the limited number of higher educated people living in the communities surrounding the mining operations and lack of interest in mining of people with higher levels of education, to name but few, employers are perceived to have a habit of employing people with little skills. The current study was aimed at investigating the impact of skills shortage on organisational performance, propensity to leave, competitive advantage and sustainability, from the management perceptive. The main objective of this study was to incorporate and embed previous research findings and theories into a comprehensive hypothetical model. A hypothetical model showed various factors that may influence skills shortage. Four independent variables (working environment, employment conditions, resources and education and training) were identified as variables that may influence skills shortage; and mediating variable (skills shortage) was also identified as a variable that have potential to affect dependent variables (organisational performance, propensity to leave, competitive advantage and sustainability) of gold mining sector. Furthermore, eight hypotheses were developed to test the relationship between independent, mediating and dependent variables. All these variables were clearly defined and operationalized with various items obtained from measuring instruments used in other similar studies. A purposive sample of 343 respondents was drawn from the population. A seven-point Likert scale and structured questionnaire were administered in person to the respondents and of which 300 were usable and subjected further to several statistical analyses. The validity and reliability of the measuring instrument was evaluated using significant effect p< = 0.001 and Pearson’s correlation test (α = 0.05). Data gathered were fed to and analysed by STATISTICA (version 10) and factor analysis and regression analyses were the statistical procedures used to test the significance of the relationships between the various independent and dependent variables. Consequently, working environment, resources and education and training were three independent variables that were identified as having ability to predict propensity to leave, competitive advantage and sustainability. An attempt was made to establish whether various demographic variables have an influence on mediating and dependent variables through the introduction of gender and position in the organisation while conducting an Analysis of Variance and Multiple linear regressions, but they obtained negative values. The conclusion is that demographic variables do not have over mediating and depended variables. The findings of this study states that with conducive working environment, availability of resources, the high levels of education and training, the country could produce skills that would reduce propensity to leave, drive competitive advantage and sustainability, innovation and entrepreneurship, create competitive advantages and boost employment sustainability.
- Full Text:
- Date Issued: 2012
- Authors: Xingwana, Lumkwana
- Date: 2012
- Subjects: Labor supply--South Africa , Professional employees--South Africa , Occupational training--South Africa , Gold mines and mining--South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9279 , http://hdl.handle.net/10948/d1007959 , Labor supply--South Africa , Professional employees--South Africa , Occupational training--South Africa , Gold mines and mining--South Africa
- Description: The skills shortages in mining and mineral sector had existed for a decade and had a widespread effect on South Africa economy. It affects the level of economic productivity and reduces the country’s capacity to develop a knowledge society. This, in turn, affects the country’s functioning in the global economy. Despite the sector’s best efforts, the shortages continue to grow and threaten the delivery of projects and growth plans. Some researchers contend with the view that the persistence of skills shortages in mining and mineral sector is largely due to entrenched attitudes among both the industry and the community. They claim that employers have the means to change the educational profile of the subsectors by appointing recruits with higher levels of schooling. However, owing to the limited number of higher educated people living in the communities surrounding the mining operations and lack of interest in mining of people with higher levels of education, to name but few, employers are perceived to have a habit of employing people with little skills. The current study was aimed at investigating the impact of skills shortage on organisational performance, propensity to leave, competitive advantage and sustainability, from the management perceptive. The main objective of this study was to incorporate and embed previous research findings and theories into a comprehensive hypothetical model. A hypothetical model showed various factors that may influence skills shortage. Four independent variables (working environment, employment conditions, resources and education and training) were identified as variables that may influence skills shortage; and mediating variable (skills shortage) was also identified as a variable that have potential to affect dependent variables (organisational performance, propensity to leave, competitive advantage and sustainability) of gold mining sector. Furthermore, eight hypotheses were developed to test the relationship between independent, mediating and dependent variables. All these variables were clearly defined and operationalized with various items obtained from measuring instruments used in other similar studies. A purposive sample of 343 respondents was drawn from the population. A seven-point Likert scale and structured questionnaire were administered in person to the respondents and of which 300 were usable and subjected further to several statistical analyses. The validity and reliability of the measuring instrument was evaluated using significant effect p< = 0.001 and Pearson’s correlation test (α = 0.05). Data gathered were fed to and analysed by STATISTICA (version 10) and factor analysis and regression analyses were the statistical procedures used to test the significance of the relationships between the various independent and dependent variables. Consequently, working environment, resources and education and training were three independent variables that were identified as having ability to predict propensity to leave, competitive advantage and sustainability. An attempt was made to establish whether various demographic variables have an influence on mediating and dependent variables through the introduction of gender and position in the organisation while conducting an Analysis of Variance and Multiple linear regressions, but they obtained negative values. The conclusion is that demographic variables do not have over mediating and depended variables. The findings of this study states that with conducive working environment, availability of resources, the high levels of education and training, the country could produce skills that would reduce propensity to leave, drive competitive advantage and sustainability, innovation and entrepreneurship, create competitive advantages and boost employment sustainability.
- Full Text:
- Date Issued: 2012
The relationship between health and safety and human risk taking behaviour in the South African electrical construction industry
- Authors: Du Toit, Willem Johannes
- Date: 2012
- Subjects: Electrical engineering -- Safety measures , Electrical engineering -- Health aspects , Construction industry -- Safety measures , Psychology, industrial
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9691 , http://hdl.handle.net/10948/d1009529 , Electrical engineering -- Safety measures , Electrical engineering -- Health aspects , Construction industry -- Safety measures , Psychology, industrial
- Description: Mankind, and the development of people, exists due to risk-taking behaviour. It is not that humans should not take risks, but rather the ability to identify the magnitude of risk exposure in order that mankind‟s actions would be so selected as to mitigate exposed risk factors, that no harm should befall them. The approach to health and safety (H&S) has always been to manage H&S environmental factors that could have a negative impact on people, capital, and organisational systems. However, the critical component of human risk-taking behaviour that would have a far greater impact has rarely been acknowledged as part of the drivers that increase risk exposure. Human behaviour is a major contributing factor in accident causation. Although human error cannot be completely eliminated, it should be identified and correctly managed according to each individual‟s risk-taking profile. The reason people decide to take certain risks under certain conditions and the effect it has on H&S management systems is a key component to managing organisational risk exposure. To quantify the value of individual risk-taking behaviour could provide management with better opportunities of lowering the organisational risk exposure. Human risk-taking behaviour is influenced by each individual‟s perception of risk. Such perception of risk will influence decisions on risk-taking behaviour, which in turn is influenced by the individual‟s psychological profile and environmental factors, including character and the impact of a cultural environment. The electrical construction and maintenance industry differs from other similar industries in that the physical entity of electricity requires not only sensory perception for the identification and evaluation of risk factors, but also requires specialised knowledge and testing equipment to evaluate the parameters of electrical installation, plant or equipment. Without such competence, direct exposure to most electrical installations could be fatal. The optimum human resource (HR) solution for managing the risk potential of high risk-taking behaviour is the rating and allocation of specific job tasks that can match and limit the individual potential for risk-taking behaviour and the impact on organisational incident statistics. Maintaining and optimising employee job performance enables organisations to better achieve pre-set goals and missions. Such improvements being a catalyst for better job performance by setting limitations on high risk-taking behaviour, that will improve H&S performance by lowering incident rates.
- Full Text:
- Date Issued: 2012
- Authors: Du Toit, Willem Johannes
- Date: 2012
- Subjects: Electrical engineering -- Safety measures , Electrical engineering -- Health aspects , Construction industry -- Safety measures , Psychology, industrial
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9691 , http://hdl.handle.net/10948/d1009529 , Electrical engineering -- Safety measures , Electrical engineering -- Health aspects , Construction industry -- Safety measures , Psychology, industrial
- Description: Mankind, and the development of people, exists due to risk-taking behaviour. It is not that humans should not take risks, but rather the ability to identify the magnitude of risk exposure in order that mankind‟s actions would be so selected as to mitigate exposed risk factors, that no harm should befall them. The approach to health and safety (H&S) has always been to manage H&S environmental factors that could have a negative impact on people, capital, and organisational systems. However, the critical component of human risk-taking behaviour that would have a far greater impact has rarely been acknowledged as part of the drivers that increase risk exposure. Human behaviour is a major contributing factor in accident causation. Although human error cannot be completely eliminated, it should be identified and correctly managed according to each individual‟s risk-taking profile. The reason people decide to take certain risks under certain conditions and the effect it has on H&S management systems is a key component to managing organisational risk exposure. To quantify the value of individual risk-taking behaviour could provide management with better opportunities of lowering the organisational risk exposure. Human risk-taking behaviour is influenced by each individual‟s perception of risk. Such perception of risk will influence decisions on risk-taking behaviour, which in turn is influenced by the individual‟s psychological profile and environmental factors, including character and the impact of a cultural environment. The electrical construction and maintenance industry differs from other similar industries in that the physical entity of electricity requires not only sensory perception for the identification and evaluation of risk factors, but also requires specialised knowledge and testing equipment to evaluate the parameters of electrical installation, plant or equipment. Without such competence, direct exposure to most electrical installations could be fatal. The optimum human resource (HR) solution for managing the risk potential of high risk-taking behaviour is the rating and allocation of specific job tasks that can match and limit the individual potential for risk-taking behaviour and the impact on organisational incident statistics. Maintaining and optimising employee job performance enables organisations to better achieve pre-set goals and missions. Such improvements being a catalyst for better job performance by setting limitations on high risk-taking behaviour, that will improve H&S performance by lowering incident rates.
- Full Text:
- Date Issued: 2012
Synthetic and bioactivity studies of antiplasmodial and antibacterial marine natural products
- Authors: Young, Ryan Mark
- Date: 2012
- Subjects: Antibacterial agents Marine natural products Marine pharmacology Plasmodium falciparum Staphylococcus aureus Isocyanides Imidazoles
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4378 , http://hdl.handle.net/10962/d1005043
- Description: This thesis is divided into two parts, assessing marine and synthetic compounds active firstly against Plasmodium falciparum (Chapter 3 and 4) and secondly active against methicillin resistant Staphylococcus aureus (MRSA, Chapter 5). In Chapter 3 the synthesis of nine new tricyclic podocarpanes (3.203-3.207 and 3.209-3.212) from the diterpene (+)-manool is described. Initial SAR study of synthetic podocarpanes concluded that the most active compound was a C-13 phenyl substituted podocarpane (3.204, IC₅₀ 6.6 μM). By preparing analogues with varying halogenated substituents on the phenyl ring (3.209-3.212) the antiplasmodial activity was improved (IC₅₀ 1.4 μM), while simultaneously decreasing the haemolysis previously reported for this class of compounds. Inspired by the antiplasmodial activity of Wright and Wattanapiromsakul’s tricycle marine isonitriles (2.16-2.21 and 2.24-2.27) an unsuccessfully attempt was made to convert tertiary alcohol moieties to isonitrile functionalities in compounds 3.188, 3.204-3.207 and 3.209-3.212. Over a decade ago Wright et al. proposed a putative antiplasmodial mechanism of action for marine isonitriles (2.4, 2.9, 2.15, 2.19 and 2.35) and isothiocyanate (2.34) which involved interference in haem detoxification by P. falciparum thus inhibiting the growth of the parasite. In Chapter 4 we describe how we successfully managed to scale down Egan’s β-haematin inhibition assay for the analyses of small quantities of marine natural products as potential β-haematin inhibitors. Our modified assay revealed that the most active antiplasmodial marine isonitrile 2.9 (IC₅₀ 13 nM) showed total β-haematin inhibition while 2.15 (IC₅₀ 81 nM) and 2.19 (IC₅₀ 31 nM) showed partial inhibition at three equivalents relative to haem. Using contempary molecular modelling techniques the charge on the isonitrile functionality was more accurately describe and the modified charge data sets was used to explore docking of marine isonitriles to haem using AutoDock. In Chapter 5 we describe how a lead South African marine bisindole MRSA pyruvate kinase inhibitor (5.8) was discovered in collaboration with colleagues at the University of British Columbia (UBC) and how this discovery inspired us to design a synthetic route to the dibrominated bisindole, isobromotopsentin (5.20) in an attempt to increase the bioactivity displayed by 5.8. We devised a fast and high yielding synthetic route using microwave assited organic synthesis. We first tested this synthesis using simple aryl glyoxals (5.27-5.32) as precursors to synthesize biphenylimidazoles (5.21-5.26), which later allowed us to synthesize the ascidian natural product 5.111. This method was sucessfully extended to the synthesis of deoxytopsentin (5.33) from an N-Boc protected indole methyl ketone (5.89). We subsequently were able to effectively remove the carbamate protection via thermal decomposition by heating the protected bisindole imidazole (5.90) in a microwave reactor for 5 min under argon. The synthesis of 5.20 resulted in an inseparable mixture of monoprotected and totally deprotected topsentin products, and due to time constraints we were not able to optimise this synthesis. Nonetheless our synthesis of the marine natural product 5.33 which was faster and higher yielding than previously reported routes could be extended to the synthesis of other topsentin bisindoles (5.138-5.140). Work towards this goal continues in our laboratory.
- Full Text:
- Date Issued: 2012
- Authors: Young, Ryan Mark
- Date: 2012
- Subjects: Antibacterial agents Marine natural products Marine pharmacology Plasmodium falciparum Staphylococcus aureus Isocyanides Imidazoles
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4378 , http://hdl.handle.net/10962/d1005043
- Description: This thesis is divided into two parts, assessing marine and synthetic compounds active firstly against Plasmodium falciparum (Chapter 3 and 4) and secondly active against methicillin resistant Staphylococcus aureus (MRSA, Chapter 5). In Chapter 3 the synthesis of nine new tricyclic podocarpanes (3.203-3.207 and 3.209-3.212) from the diterpene (+)-manool is described. Initial SAR study of synthetic podocarpanes concluded that the most active compound was a C-13 phenyl substituted podocarpane (3.204, IC₅₀ 6.6 μM). By preparing analogues with varying halogenated substituents on the phenyl ring (3.209-3.212) the antiplasmodial activity was improved (IC₅₀ 1.4 μM), while simultaneously decreasing the haemolysis previously reported for this class of compounds. Inspired by the antiplasmodial activity of Wright and Wattanapiromsakul’s tricycle marine isonitriles (2.16-2.21 and 2.24-2.27) an unsuccessfully attempt was made to convert tertiary alcohol moieties to isonitrile functionalities in compounds 3.188, 3.204-3.207 and 3.209-3.212. Over a decade ago Wright et al. proposed a putative antiplasmodial mechanism of action for marine isonitriles (2.4, 2.9, 2.15, 2.19 and 2.35) and isothiocyanate (2.34) which involved interference in haem detoxification by P. falciparum thus inhibiting the growth of the parasite. In Chapter 4 we describe how we successfully managed to scale down Egan’s β-haematin inhibition assay for the analyses of small quantities of marine natural products as potential β-haematin inhibitors. Our modified assay revealed that the most active antiplasmodial marine isonitrile 2.9 (IC₅₀ 13 nM) showed total β-haematin inhibition while 2.15 (IC₅₀ 81 nM) and 2.19 (IC₅₀ 31 nM) showed partial inhibition at three equivalents relative to haem. Using contempary molecular modelling techniques the charge on the isonitrile functionality was more accurately describe and the modified charge data sets was used to explore docking of marine isonitriles to haem using AutoDock. In Chapter 5 we describe how a lead South African marine bisindole MRSA pyruvate kinase inhibitor (5.8) was discovered in collaboration with colleagues at the University of British Columbia (UBC) and how this discovery inspired us to design a synthetic route to the dibrominated bisindole, isobromotopsentin (5.20) in an attempt to increase the bioactivity displayed by 5.8. We devised a fast and high yielding synthetic route using microwave assited organic synthesis. We first tested this synthesis using simple aryl glyoxals (5.27-5.32) as precursors to synthesize biphenylimidazoles (5.21-5.26), which later allowed us to synthesize the ascidian natural product 5.111. This method was sucessfully extended to the synthesis of deoxytopsentin (5.33) from an N-Boc protected indole methyl ketone (5.89). We subsequently were able to effectively remove the carbamate protection via thermal decomposition by heating the protected bisindole imidazole (5.90) in a microwave reactor for 5 min under argon. The synthesis of 5.20 resulted in an inseparable mixture of monoprotected and totally deprotected topsentin products, and due to time constraints we were not able to optimise this synthesis. Nonetheless our synthesis of the marine natural product 5.33 which was faster and higher yielding than previously reported routes could be extended to the synthesis of other topsentin bisindoles (5.138-5.140). Work towards this goal continues in our laboratory.
- Full Text:
- Date Issued: 2012
An investigation of persistence of rural poverty in South Africa: the case of O.R. Tambo district municipality
- Authors: Kongwa, Kekelwa Samuele
- Date: 2012
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11443 , http://hdl.handle.net/10353/d1007577
- Description: The purpose of this study was an investigation of the reasons for persistent poverty and low level of economic growth and development in the OR Tambo district municipality of the Eastern Cape Province since the advent of democracy in South Africa. To accomplish this objective, a case study of the OR Tambo district municipality was undertaken within the concept of development, seeking to answer three research questions: What are the factors that explain the persistence of poverty in the OR Tambo district municipality? Why is the OR Tambo district municipality the most exposed to poverty in relative and absolute terms? What have state poverty intervention strategies done to alleviate poverty in the OR Tambo district since the advent of democracy in South Africa? Mainly qualitative data collection methods, involving in-depth semi-structured interviews, textual and document analyses, focus group discussions and observations were employed to answer the research questions. A purposive sampling of nineteen participants, supplemented by three focus groups, was selected. The macro-level case study design was supplemented by micro-level documentary evidence on poverty and development. From the synthesised findings of the investigation, twelve causal factors were identified as responsible for persistent poverty and low level of economic growth and development in the OR Tambo district. These included political neglect, agricultural neglect, poor infrastructure, corruption, poor service delivery, poor quality of natural resources, brain drain, migrant labour system, culture of tolerance and conservatism, culture of dependence, no long-term development strategy and globalisation.
- Full Text:
- Date Issued: 2012
- Authors: Kongwa, Kekelwa Samuele
- Date: 2012
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11443 , http://hdl.handle.net/10353/d1007577
- Description: The purpose of this study was an investigation of the reasons for persistent poverty and low level of economic growth and development in the OR Tambo district municipality of the Eastern Cape Province since the advent of democracy in South Africa. To accomplish this objective, a case study of the OR Tambo district municipality was undertaken within the concept of development, seeking to answer three research questions: What are the factors that explain the persistence of poverty in the OR Tambo district municipality? Why is the OR Tambo district municipality the most exposed to poverty in relative and absolute terms? What have state poverty intervention strategies done to alleviate poverty in the OR Tambo district since the advent of democracy in South Africa? Mainly qualitative data collection methods, involving in-depth semi-structured interviews, textual and document analyses, focus group discussions and observations were employed to answer the research questions. A purposive sampling of nineteen participants, supplemented by three focus groups, was selected. The macro-level case study design was supplemented by micro-level documentary evidence on poverty and development. From the synthesised findings of the investigation, twelve causal factors were identified as responsible for persistent poverty and low level of economic growth and development in the OR Tambo district. These included political neglect, agricultural neglect, poor infrastructure, corruption, poor service delivery, poor quality of natural resources, brain drain, migrant labour system, culture of tolerance and conservatism, culture of dependence, no long-term development strategy and globalisation.
- Full Text:
- Date Issued: 2012
A psycho-educational programme to facilitate the mental health of adolescent girls who are victims of verbal bullying
- Authors: Jacobs, Ruwayda
- Date: 2012
- Subjects: Teenage girls -- Mental health -- South Africa , Psychoanalysis , Bullying
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9946 , http://hdl.handle.net/10948/d1014579
- Description: Bullying appears to be a worldwide phenomenon. It occurs within schools, homes, and in the community too. Bullying is a form of aggressive behaviour. Female bullying is not so easily noticed, as girls hardly ever use physical forms of aggression. Bullying can have a detrimental effect on the mental health of the victim. The victims of bullying experience symptoms of mental discomfort, which include low self esteem, feelings of helplessness, feelings of worthlessness and inferiority, lack of confidence, isolation, self-conscientiousness; and lastly, this can lead to suicide. Some form of intervention is necessary to provide adolescents with skills to combat bullying and help them to become mentally healthy again. The overall goal of the study was to develop, implement and evaluate a psycho-educational programme for female adolescents in a secondary school setting, in order to assist them in coping with bullying. The objectives of the research study were to: Conduct asituational analysis to identify the mental health needs of adolescent girls, as victimsof bullying. Develop a psycho-educational programme to facilitate the promotion of mental health of those adolescent girls who are victims of bullying. Implement the psycho-educational programme to facilitate coping by adolescent girls who are victims of bullying. Assess whether the adolescent girls have benefitted from attending the psycho-educational programme. The researcher used a qualitative, explorative, descriptive and contextual design. The research methodology consisted of four phases. In phase one of the research, a situational analysis was done; and the characteristics of mental discomfort exhibited by the victim were identified. The needs of the adolescent girl who has been bullied have already been described. Phase two involved the development of a psycho-educational programme. The information from the situational analysis was used to develop the conceptual framework. The six concepts in the survey list of Dickoff et al. (1968:422) were described as follows: the recipient is the adolescent girl who has been bullied, the agent is an advanced psychiatric nurse, the context is the community and the secondary school where bullying takes place, the dynamics of the intervention constitute the mental discomfort experienced by the adolescent girl. This is what motivates her to participate in the programme. The procedure was identified as the psycho-educational programme, while the terminus or outcome of the intervention for the adolescent girl would be for her to experience mental health after being exposed to the psycho-educational programme. The relationship between the concepts was used to form the mind map of the conceptual framework. This guided the development of the psycho-educational programme. The content of the programme has already been described. In phase three the psycho-educational programme is implemented and in phase four the programme is evaluated. The psycho-educational programme taught the teenage girls skills and it provided them with knowledge to cope better with the bullying. Attending the programme made the teenagers aware that they needed to change to experience mental health and happiness. The empirical study took place in phase four. The data-gathering method in phase four included the conducting of semi-structured interviews with the adolescent girls who participated in the programme, as well as the teachers of these adolescent girls and their parents. Naïve sketches, reflective journals, observations made and field notes formed part of this database. The data was analyzed by means of Tesch‟s descriptive analysis (in Creswell, 2003:192). The participants had to comment on how they were coping after the implementation of the psycho-educational programme. In conclusion, an intervention in the form of the psycho-educational programme was shown to be beneficial to adolescent girls who were victims of bullying, to assist them in coping with the aftermath of being bullied. Recommendations were made to enhance nursing practice, as well as nursing education and nursing research. Keywords: Adolescent girls, bullying, secondary schools, advanced psychiatric nurse, psycho-educational programme, mental health.
- Full Text:
- Date Issued: 2012
- Authors: Jacobs, Ruwayda
- Date: 2012
- Subjects: Teenage girls -- Mental health -- South Africa , Psychoanalysis , Bullying
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9946 , http://hdl.handle.net/10948/d1014579
- Description: Bullying appears to be a worldwide phenomenon. It occurs within schools, homes, and in the community too. Bullying is a form of aggressive behaviour. Female bullying is not so easily noticed, as girls hardly ever use physical forms of aggression. Bullying can have a detrimental effect on the mental health of the victim. The victims of bullying experience symptoms of mental discomfort, which include low self esteem, feelings of helplessness, feelings of worthlessness and inferiority, lack of confidence, isolation, self-conscientiousness; and lastly, this can lead to suicide. Some form of intervention is necessary to provide adolescents with skills to combat bullying and help them to become mentally healthy again. The overall goal of the study was to develop, implement and evaluate a psycho-educational programme for female adolescents in a secondary school setting, in order to assist them in coping with bullying. The objectives of the research study were to: Conduct asituational analysis to identify the mental health needs of adolescent girls, as victimsof bullying. Develop a psycho-educational programme to facilitate the promotion of mental health of those adolescent girls who are victims of bullying. Implement the psycho-educational programme to facilitate coping by adolescent girls who are victims of bullying. Assess whether the adolescent girls have benefitted from attending the psycho-educational programme. The researcher used a qualitative, explorative, descriptive and contextual design. The research methodology consisted of four phases. In phase one of the research, a situational analysis was done; and the characteristics of mental discomfort exhibited by the victim were identified. The needs of the adolescent girl who has been bullied have already been described. Phase two involved the development of a psycho-educational programme. The information from the situational analysis was used to develop the conceptual framework. The six concepts in the survey list of Dickoff et al. (1968:422) were described as follows: the recipient is the adolescent girl who has been bullied, the agent is an advanced psychiatric nurse, the context is the community and the secondary school where bullying takes place, the dynamics of the intervention constitute the mental discomfort experienced by the adolescent girl. This is what motivates her to participate in the programme. The procedure was identified as the psycho-educational programme, while the terminus or outcome of the intervention for the adolescent girl would be for her to experience mental health after being exposed to the psycho-educational programme. The relationship between the concepts was used to form the mind map of the conceptual framework. This guided the development of the psycho-educational programme. The content of the programme has already been described. In phase three the psycho-educational programme is implemented and in phase four the programme is evaluated. The psycho-educational programme taught the teenage girls skills and it provided them with knowledge to cope better with the bullying. Attending the programme made the teenagers aware that they needed to change to experience mental health and happiness. The empirical study took place in phase four. The data-gathering method in phase four included the conducting of semi-structured interviews with the adolescent girls who participated in the programme, as well as the teachers of these adolescent girls and their parents. Naïve sketches, reflective journals, observations made and field notes formed part of this database. The data was analyzed by means of Tesch‟s descriptive analysis (in Creswell, 2003:192). The participants had to comment on how they were coping after the implementation of the psycho-educational programme. In conclusion, an intervention in the form of the psycho-educational programme was shown to be beneficial to adolescent girls who were victims of bullying, to assist them in coping with the aftermath of being bullied. Recommendations were made to enhance nursing practice, as well as nursing education and nursing research. Keywords: Adolescent girls, bullying, secondary schools, advanced psychiatric nurse, psycho-educational programme, mental health.
- Full Text:
- Date Issued: 2012
Electrospun nanofibers : an alternative sorbent material for solid phase extraction
- Chigome, Samuel, Samuel Chigome
- Authors: Chigome, Samuel , Samuel Chigome
- Date: 2012 , 2012-03-26
- Subjects: Nanofibers -- Research Electrospinning -- Research Sorbents -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4314 , http://hdl.handle.net/10962/d1004972
- Description: The work described in the thesis seeks to lay a foundation for a better understanding of the use of electrospun nanofibers as a sorbent material. Three miniaturised electrospun nanofiber based solid phase extraction devices were fabricated. For the first two, 10 mg of electrospun polystyrene fibers were used as a sorbent bed for a micro column SPE device (8 mm bed height in a 200 μl pipette tip) and a disk (I) SPE device (5 mm 1 mm sorbent bed in a 1000 μl SPE barrel). While for the third, 4.6 mg of electrospun nylon nanofibers were used as a sorbent bed for a disk (II) SPE device, (sorbent bed consisting of 5 5 mm 350 μm stacked disks in a 500 μl SPE barrel). Corticosteroids were employed as model analytes for performance evaluation of the fabricated SPE devices. Quantitative recoveries (45.5-124.29 percent) were achieved for all SPE devices at a loading volume of 100 μl and analyte concentration of 500 ng ml-1. Three mathematical models; the Boltzmann, Weibull five parameter and the Sigmoid three parameter were employed to describe the break through profiles of each of the sorbent beds. The micro column SPE device exhibited a breakthrough volume of 1400 μl, and theoretical plates (7.98-9.1) while disk (I) SPE device exhibited 400-500 μl and 1.39-2.82 respectively. Disk (II) SPE device exhibited a breakthrough volume of 200 μl and theoretical plates 0.38-1.15. It was proposed that the formats of future electrospun nanofiber sorbent based SPE devices will be guided by mechanical strength of the polymer. The study classified electrospun polymer fibers into two as polystyrene type (relatively low mechanical strength) and nylon type (relatively high mechanical strength).
- Full Text:
- Date Issued: 2012
- Authors: Chigome, Samuel , Samuel Chigome
- Date: 2012 , 2012-03-26
- Subjects: Nanofibers -- Research Electrospinning -- Research Sorbents -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4314 , http://hdl.handle.net/10962/d1004972
- Description: The work described in the thesis seeks to lay a foundation for a better understanding of the use of electrospun nanofibers as a sorbent material. Three miniaturised electrospun nanofiber based solid phase extraction devices were fabricated. For the first two, 10 mg of electrospun polystyrene fibers were used as a sorbent bed for a micro column SPE device (8 mm bed height in a 200 μl pipette tip) and a disk (I) SPE device (5 mm 1 mm sorbent bed in a 1000 μl SPE barrel). While for the third, 4.6 mg of electrospun nylon nanofibers were used as a sorbent bed for a disk (II) SPE device, (sorbent bed consisting of 5 5 mm 350 μm stacked disks in a 500 μl SPE barrel). Corticosteroids were employed as model analytes for performance evaluation of the fabricated SPE devices. Quantitative recoveries (45.5-124.29 percent) were achieved for all SPE devices at a loading volume of 100 μl and analyte concentration of 500 ng ml-1. Three mathematical models; the Boltzmann, Weibull five parameter and the Sigmoid three parameter were employed to describe the break through profiles of each of the sorbent beds. The micro column SPE device exhibited a breakthrough volume of 1400 μl, and theoretical plates (7.98-9.1) while disk (I) SPE device exhibited 400-500 μl and 1.39-2.82 respectively. Disk (II) SPE device exhibited a breakthrough volume of 200 μl and theoretical plates 0.38-1.15. It was proposed that the formats of future electrospun nanofiber sorbent based SPE devices will be guided by mechanical strength of the polymer. The study classified electrospun polymer fibers into two as polystyrene type (relatively low mechanical strength) and nylon type (relatively high mechanical strength).
- Full Text:
- Date Issued: 2012
Photophysicochemical and photodynamic studies of phthalocyanines conjugated to selected drug delivery agents
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
- Full Text:
- Date Issued: 2012
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
- Full Text:
- Date Issued: 2012
Media and agriculture in Africa : a case study of agriculture radio programming in Malawi
- Authors: Manda, Levison Zeleza
- Date: 2012
- Subjects: Radio in agriculture -- Malawi , Communication -- Agriculture -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:8434 , http://hdl.handle.net/10948/d1020925
- Description: This thesis argues that although participatory communication for development has been extolled to be more effective than the monologic or top-down communication approaches associated with the modernization development paradigm, its influence in making Malawian smallholder farmers adopt radio-mediated innovations and technologies seems to be minimal and ought to be reconsidered for more effective communication for development models. The study used mostly qualitative methodology, with focus group discussions, key informant interviews, and a semi-structured questionnaire to gather verbal and statistical from the primary beneficiaries in order data to understand why three mass media interventions in Malawi had similar effects when only one of them was strictly participatory. It found, inter alia, that in two sites food security was the overriding factor that influenced the community members to adopt radio messages while in the third the participants were mostly driven by the desire to earn money, essentially because the area is food-secure. Thus, participation in radio production was found not to have any significant role in the acceptance and adoption of radio-mediated innovations by the farming communities. Based on the above findings, the study recommends a) an integrated communication for development (IC4D) model that combines top-down information dissemination techniques and participatory communication approaches since the two reinforce more than they oppose each other, and b) the formation of a Communication for Development (C4D) pool fund in Malawi to finance C4D activities. The C4D pool fund is theorised to be resourced by the Malawi government departments, local farmers ‘organisations, international NGOs, and UN bodies such as UNICEF, WHO, and the FAO.
- Full Text:
- Date Issued: 2012
- Authors: Manda, Levison Zeleza
- Date: 2012
- Subjects: Radio in agriculture -- Malawi , Communication -- Agriculture -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:8434 , http://hdl.handle.net/10948/d1020925
- Description: This thesis argues that although participatory communication for development has been extolled to be more effective than the monologic or top-down communication approaches associated with the modernization development paradigm, its influence in making Malawian smallholder farmers adopt radio-mediated innovations and technologies seems to be minimal and ought to be reconsidered for more effective communication for development models. The study used mostly qualitative methodology, with focus group discussions, key informant interviews, and a semi-structured questionnaire to gather verbal and statistical from the primary beneficiaries in order data to understand why three mass media interventions in Malawi had similar effects when only one of them was strictly participatory. It found, inter alia, that in two sites food security was the overriding factor that influenced the community members to adopt radio messages while in the third the participants were mostly driven by the desire to earn money, essentially because the area is food-secure. Thus, participation in radio production was found not to have any significant role in the acceptance and adoption of radio-mediated innovations by the farming communities. Based on the above findings, the study recommends a) an integrated communication for development (IC4D) model that combines top-down information dissemination techniques and participatory communication approaches since the two reinforce more than they oppose each other, and b) the formation of a Communication for Development (C4D) pool fund in Malawi to finance C4D activities. The C4D pool fund is theorised to be resourced by the Malawi government departments, local farmers ‘organisations, international NGOs, and UN bodies such as UNICEF, WHO, and the FAO.
- Full Text:
- Date Issued: 2012
Development of a hydraulic sub-model as part of a desktop environmental flow assessment method
- Authors: Desai, Ahmed Yacoob
- Date: 2012
- Subjects: Hydrologic models -- Research -- South Africa Hydraulic engineering -- South Africa Rivers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6041 , http://hdl.handle.net/10962/d1006200
- Description: Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.
- Full Text:
- Date Issued: 2012
- Authors: Desai, Ahmed Yacoob
- Date: 2012
- Subjects: Hydrologic models -- Research -- South Africa Hydraulic engineering -- South Africa Rivers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6041 , http://hdl.handle.net/10962/d1006200
- Description: Countries around the world have been developing ecological policies to protect their water resources and minimise the impacts of development on their river systems. The concept of ‘minimum flows’ was initially established as a solution but it did not provide sufficient protection as all elements of a flow regime were found to be important for the protection of the river ecosystem. “Environmental flows” were developed to determine these flow regimes to maintain a river in some defined ecological condition. Rapid, initial estimates of the quantity component of environmental flows may be determined using the Desktop Reserve Model in South Africa. However, the Desktop Reserve Model is dependent upon the characteristics of the reference natural hydrology used. The advancements in hydraulic and ecological relationships from the past decade have prompted the development of a Revised Desktop Reserve Model (RDRM) that would incorporate these relationships. The research in this thesis presents the development of the hydraulic sub-model for the RDRM. The hydraulic sub-model was designed to produce a realistic representation of the hydraulic conditions using hydraulic parameters/characteristics from readily available information for any part of South Africa. Hydraulic data from past EWR studies were used to estimate the hydraulic parameters. These estimated hydraulic parameters were used to develop hydraulic estimation relationships and these relationships were developed based on a combination of regression and rule-based procedures. The estimation relationships were incorporated into the hydraulic sub-model of the integrated RDRM and assessments of the hydraulic outputs and EWR results were undertaken to assess the ‘applicability’ of the hydraulic sub-model. The hydraulic sub-model was assessed to be at a stage where it can satisfactorily be incorporated in the RDRM and that it is adequately robust in many situations. Recommendations for future work include the refinement of estimation of the channel forming discharge or the use of spatial imagery to check the maximum channel width estimation. It is also proposed that a future version of the hydraulic sub-model could include flow regime change impacts on channel geomorphology and sedimentology so that flow management scenarios can be more effectively assessed.
- Full Text:
- Date Issued: 2012
An action learning model to assist circuit teams to support school management teams towards whole-school development
- Van der Voort, Geoffrey Hermanus
- Authors: Van der Voort, Geoffrey Hermanus
- Date: 2012
- Subjects: Action research in education -- South Africa -- Cape Town , School management teams -- South Africa -- Cape Town , Low-performing schools -- South Africa -- Cape Town , School improvement programs -- South Africa -- Cape Town , Active learning -- South Africa -- Cape Town
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9567 , http://hdl.handle.net/10948/d1016065
- Description: This research study took as its point of departure the general state of underperformance of the majority of schools in South Africa. A review of the literature uncovered evidence that suggested that the state of school management in the majority of schools was in disarray. The problem was compounded by the poor quality and haphazard nature of support that District and Circuit Officials of the Education Department rendered to schools. I therefore saw the need to conduct a scientific investigation into how Circuit Teams could be assisted to support School Management Teams towards whole-school development. Against this background, I formulated the following primary research question to guide the study: “How can Circuit Teams effectively support School Management Teams of underperforming schools towards whole-school development?” The following secondary research questions arose out of this to provide further direction to the study: How can Circuit Teams assist School Management Teams to develop and implement their respective School Improvement Plans? How can Circuit Teams be assisted to develop, implement and monitor their Circuit Improvement Plans? What recommendations can be made to improve service delivery to the schools?. The primary aim of the research was therefore to design an action learning model that would enable Circuit Teams to support School Management Teams of underperforming high schools towards whole-school development. A qualitative research approach was adopted for this study, as it best suited the purpose of the research, and the philosophical assumptions of the researcher. In addition, I drew on a constructivist-interpretative and a critical theory paradigm to guide the design. I chose action research as the specific methodology for the study as, in line with critical theory it aims to empower people to facilitate social change and improvement at a local level. Purposive sampling was used to select four underperforming high schools in the same township within the Cape Town Metro, belonging to the same education Circuit and District Office to participate in the research. In addition, the members of the Circuit Team that serviced these schools were also brought on board as participants. In total, 40 people participated in the research: 4 members from the Circuit Team, 4 Principals, 8 Deputy Principals and 24 Heads of Department. Data were generated in the period January to June 2012 using structured, semi-structured and unstructured interviews, participant observation, and document analysis. Data were analysed by following the eight steps for analysing qualitative data identified by Tesch. An Action Research cycle consisting of the following five steps was followed with participants during the fieldwork, viz.: Identification of the problem; Designing the action plan; Implementing the action plan; Evaluating the action, and Reflection and lessons learnt. Two Action Research cycles emerged from the fieldwork. The first cycle dealt with assisting the schools and Circuit Team to construct their improvement plans. The main findings from this cycle were (1) that the Circuit Team did not function as a team, due to the autocratic management style of the Circuit Team Manager, and the plan of action to address the underperforming schools was not developed in a participative manner. In addition, the Circuit Team had no Circuit Improvement Plan in place with which to support the schools. (2) The schools did not receive the required support to prepare their School Improvement Plans, and although they were able to articulate their areas of support needed, none of them undertook the process of School Self-Evaluation and therefore did not have School Improvement Plans in place. The second action r esearch cycle dealt with the support that schools needed from the other pillars of the District Office to implement their intervention plans. Three themes emerged from this action research cycle: (1) The School Management Teams required capacitybuilding to manage their schools effectively, (2) teachers needed support to implement the curriculum, and (3) learners required assistance to achieve better results. As the outcome of the research, a spiral model consisting of three distinctive phases, each having several loops that describe the particular action that Circuit Teams and School Management Teams have to undertake was developed as the ultimate outcome of the research. The structure of the model was explained, and explicit guidelines for operationalizing it in practice were provided. Based on the findings and the construction of the model, a number of recommendations were put forward to guide future research and practice in the area of Circuit Team support to nderperforming schools. In conclusion, this research study contributed to the body of knowledge by exploring, investigating and describing the working relationship between Circuit Teams and School Management Teams, which until now has not been adequately covered in the existing literature and research. The study culminated in a theoretical model which can be used to improve this relationship permitting Circuit Teams to better support School Management Teams towards whole-school development. The action research design also allowed a more participative and democratic relationship to develop between the Circuit Team and the School Management Teams of the four schools, which is also an innovative idea considering the traditional hierarchic and autocratic approach which has been the norm in the past. Hopefully the findings of this study will encourage the emergence of democratic partnerships between Departmental officials and school management, leading to the empowerment and transformation of school management.
- Full Text:
- Date Issued: 2012
- Authors: Van der Voort, Geoffrey Hermanus
- Date: 2012
- Subjects: Action research in education -- South Africa -- Cape Town , School management teams -- South Africa -- Cape Town , Low-performing schools -- South Africa -- Cape Town , School improvement programs -- South Africa -- Cape Town , Active learning -- South Africa -- Cape Town
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9567 , http://hdl.handle.net/10948/d1016065
- Description: This research study took as its point of departure the general state of underperformance of the majority of schools in South Africa. A review of the literature uncovered evidence that suggested that the state of school management in the majority of schools was in disarray. The problem was compounded by the poor quality and haphazard nature of support that District and Circuit Officials of the Education Department rendered to schools. I therefore saw the need to conduct a scientific investigation into how Circuit Teams could be assisted to support School Management Teams towards whole-school development. Against this background, I formulated the following primary research question to guide the study: “How can Circuit Teams effectively support School Management Teams of underperforming schools towards whole-school development?” The following secondary research questions arose out of this to provide further direction to the study: How can Circuit Teams assist School Management Teams to develop and implement their respective School Improvement Plans? How can Circuit Teams be assisted to develop, implement and monitor their Circuit Improvement Plans? What recommendations can be made to improve service delivery to the schools?. The primary aim of the research was therefore to design an action learning model that would enable Circuit Teams to support School Management Teams of underperforming high schools towards whole-school development. A qualitative research approach was adopted for this study, as it best suited the purpose of the research, and the philosophical assumptions of the researcher. In addition, I drew on a constructivist-interpretative and a critical theory paradigm to guide the design. I chose action research as the specific methodology for the study as, in line with critical theory it aims to empower people to facilitate social change and improvement at a local level. Purposive sampling was used to select four underperforming high schools in the same township within the Cape Town Metro, belonging to the same education Circuit and District Office to participate in the research. In addition, the members of the Circuit Team that serviced these schools were also brought on board as participants. In total, 40 people participated in the research: 4 members from the Circuit Team, 4 Principals, 8 Deputy Principals and 24 Heads of Department. Data were generated in the period January to June 2012 using structured, semi-structured and unstructured interviews, participant observation, and document analysis. Data were analysed by following the eight steps for analysing qualitative data identified by Tesch. An Action Research cycle consisting of the following five steps was followed with participants during the fieldwork, viz.: Identification of the problem; Designing the action plan; Implementing the action plan; Evaluating the action, and Reflection and lessons learnt. Two Action Research cycles emerged from the fieldwork. The first cycle dealt with assisting the schools and Circuit Team to construct their improvement plans. The main findings from this cycle were (1) that the Circuit Team did not function as a team, due to the autocratic management style of the Circuit Team Manager, and the plan of action to address the underperforming schools was not developed in a participative manner. In addition, the Circuit Team had no Circuit Improvement Plan in place with which to support the schools. (2) The schools did not receive the required support to prepare their School Improvement Plans, and although they were able to articulate their areas of support needed, none of them undertook the process of School Self-Evaluation and therefore did not have School Improvement Plans in place. The second action r esearch cycle dealt with the support that schools needed from the other pillars of the District Office to implement their intervention plans. Three themes emerged from this action research cycle: (1) The School Management Teams required capacitybuilding to manage their schools effectively, (2) teachers needed support to implement the curriculum, and (3) learners required assistance to achieve better results. As the outcome of the research, a spiral model consisting of three distinctive phases, each having several loops that describe the particular action that Circuit Teams and School Management Teams have to undertake was developed as the ultimate outcome of the research. The structure of the model was explained, and explicit guidelines for operationalizing it in practice were provided. Based on the findings and the construction of the model, a number of recommendations were put forward to guide future research and practice in the area of Circuit Team support to nderperforming schools. In conclusion, this research study contributed to the body of knowledge by exploring, investigating and describing the working relationship between Circuit Teams and School Management Teams, which until now has not been adequately covered in the existing literature and research. The study culminated in a theoretical model which can be used to improve this relationship permitting Circuit Teams to better support School Management Teams towards whole-school development. The action research design also allowed a more participative and democratic relationship to develop between the Circuit Team and the School Management Teams of the four schools, which is also an innovative idea considering the traditional hierarchic and autocratic approach which has been the norm in the past. Hopefully the findings of this study will encourage the emergence of democratic partnerships between Departmental officials and school management, leading to the empowerment and transformation of school management.
- Full Text:
- Date Issued: 2012
Biochemical evaluation of Tulbaghia violacea harv.rhizomes in diet induced hypercholestrolemic rats
- Olorunnisola, Olubukola Sinbad
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
Megaherbivores in succulent thicket: resource use and implications
- Authors: Landman, Marietjie
- Date: 2012
- Subjects: Elephants , African elephant , Black rhinoceros , Succulent plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10689 , http://hdl.handle.net/10948/d1007956 , Elephants , African elephant , Black rhinoceros , Succulent plants
- Description: This study aims to develop a predictive understanding of the resource use, impacts and interactions of elephant Loxodonta africana and black rhinoceros Diceros bicornis in the succulent thickets of the Eastern Cape, South Africa. While these megaherbivores typically dominate the biomass, elephant are more abundant, such that their impacts off-set that of all other herbivores. Consequently, this thesis has three main foci: first, developing a mechanistic understanding of the influences of elephant; second, developing predictive insights into elephant impacts on plant communities; finally, an understanding of the knockon-effects of the impacts for coexisting rhinoceros. Thus, by documenting the diet and dietary preferences of elephant, I firstly show that only about 18 percent of the species previously thought vulnerable to herbivory, occur in the diet. This refutes the generally held belief that elephant herbivory is the primary driver of decline among plants, and emphasizes the likely contribution of other mechanisms (e.g. trampling, knock-on-effects, etc.). Thus, the accurate prediction of the impacts caused by elephant requires an understanding of previously marginalized mechanisms. From here, I quantify >50 years of impacts on the thicket shrub community and test their spatial and temporal extent near water. I confirm the vulnerability of thicket to transformation (particularly near water) as the accumulated influences of elephant reduce community composition and structure, and predict that these impacts will eventually bring about landscape-level degradation and a significant loss of biodiversity. Importantly, results show an uneven distribution of effects between elements of this community: from community composition and structure, to the structure of individual canopy species and ecological functioning. While these findings confound our interpretation of the extent of the impacts, it demonstrates the importance of explicitly recognizing biodiversity and heterogeneity for the conservation management of elephant. Finally, I test the consequences of the impacts for coexisting rhinoceros. While I show that this causes rhinoceros to change their foraging strategies in the presence of elephant at high densities, I also show that elephant may facilitate access to food for rhinoceros at reduced densities. These findings indicate the importance of elephant in driving the structure and composition of the thicket shrub community and the consequences of this for coexisting large herbivores. Thus, developing a predictive understanding of the spatial and temporal variations of elephant impacts between elements of biodiversity and the mechanisms driving these changes are key to their management. This implies that the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes.
- Full Text:
- Date Issued: 2012
- Authors: Landman, Marietjie
- Date: 2012
- Subjects: Elephants , African elephant , Black rhinoceros , Succulent plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10689 , http://hdl.handle.net/10948/d1007956 , Elephants , African elephant , Black rhinoceros , Succulent plants
- Description: This study aims to develop a predictive understanding of the resource use, impacts and interactions of elephant Loxodonta africana and black rhinoceros Diceros bicornis in the succulent thickets of the Eastern Cape, South Africa. While these megaherbivores typically dominate the biomass, elephant are more abundant, such that their impacts off-set that of all other herbivores. Consequently, this thesis has three main foci: first, developing a mechanistic understanding of the influences of elephant; second, developing predictive insights into elephant impacts on plant communities; finally, an understanding of the knockon-effects of the impacts for coexisting rhinoceros. Thus, by documenting the diet and dietary preferences of elephant, I firstly show that only about 18 percent of the species previously thought vulnerable to herbivory, occur in the diet. This refutes the generally held belief that elephant herbivory is the primary driver of decline among plants, and emphasizes the likely contribution of other mechanisms (e.g. trampling, knock-on-effects, etc.). Thus, the accurate prediction of the impacts caused by elephant requires an understanding of previously marginalized mechanisms. From here, I quantify >50 years of impacts on the thicket shrub community and test their spatial and temporal extent near water. I confirm the vulnerability of thicket to transformation (particularly near water) as the accumulated influences of elephant reduce community composition and structure, and predict that these impacts will eventually bring about landscape-level degradation and a significant loss of biodiversity. Importantly, results show an uneven distribution of effects between elements of this community: from community composition and structure, to the structure of individual canopy species and ecological functioning. While these findings confound our interpretation of the extent of the impacts, it demonstrates the importance of explicitly recognizing biodiversity and heterogeneity for the conservation management of elephant. Finally, I test the consequences of the impacts for coexisting rhinoceros. While I show that this causes rhinoceros to change their foraging strategies in the presence of elephant at high densities, I also show that elephant may facilitate access to food for rhinoceros at reduced densities. These findings indicate the importance of elephant in driving the structure and composition of the thicket shrub community and the consequences of this for coexisting large herbivores. Thus, developing a predictive understanding of the spatial and temporal variations of elephant impacts between elements of biodiversity and the mechanisms driving these changes are key to their management. This implies that the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes.
- Full Text:
- Date Issued: 2012
Comparative biogeography and ecology of freshwater fishes in the Breede and associated river systems, South Africa
- Authors: Chakona, Albert
- Date: 2012
- Subjects: Freshwater fishes -- South Africa -- Breede River , Freshwater fishes -- South Africa -- Geographical distribution , Freshwater fishes -- Ecology , Feshwater fishes -- Genetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5372 , http://hdl.handle.net/10962/d1015694
- Description: Distribution patterns and levels of genetic diversity in extant taxa are a product of complex palaeogeographic processes and climatic oscillations as well as the species’ intrinsic ecological adaptations. The Cape Floristic Region of South Africa presents a unique system for studying the processes that promote species diversification and distribution patterns. This region has a high degree of endemism of both terrestrial and aquatic biota and is clearly isolated from neighbouring areas by the Cape Fold Mountains and the Great Escarpment. The objective of this study was to firstly examine the ecology of freshwater fishes belonging to the genera Galaxias, Pseudobarbus and Sandelia in the south-western CFR. This was followed by an assessment of the genetic diversity of these taxa. Unique lineages were identified and their distribution was mapped. The work aimed to explore the role of the region’s complex palaeogeographic and climatic history as well as the role of the species’ ecological adaptations in driving lineage diversification and shaping contemporary distribution patterns. The four main components of the study can be summarised as follows: 1. Habitat associations of three widely distributed lineages of Galaxias zebratus Pseudobarbus burchelli and Sandelia capensis were evaluated at multiple localities in minimally disturbed mountain tributaries of the Breede, Duiwenhoks and Goukou River systems. The lineages have distinct habitat associations which were related to differences in their morphological traits. The slender-bodied Galaxias ‘nebula’ and the fusiform-shaped Pseudobarbus ‘Breede’ are capable of exploiting upper reaches with faster water velocity. By contrast, the laterally compressed Sandelia ‘eastern’ is restricted to lower reaches, making this lineage more susceptible to a wide array of impacts. 2. A recently discovered lineage of Galaxias zebratus, (Galaxias ‘nebula’), was found to be capable of tolerating emersion for a prolonged period of time. This is the first time that such capabilities have been documented in an African galaxiid. These adaptations have implications for the interpretation of Galaxias ‘nebula’s wide distribution range. 3. The phylogeography of Galaxias ‘nebula’ across its entire distribution range was investigated using two mitochondrial genes (cytochrome c oxidase subunit I (COI) and cytochrome b (cyt b)). This lineage has a complex evolutionary history that was influenced by both intrinsic and extrinsic factors. Rare events such as episodic drainage connections during Pleistocene and Holocene pluvial periods, possibly augmented by river confluences during periods of lower sea-levels and river capture events seem to be the most credible explanation for the extensive contemporary distribution and the relatively shallow genetic divergence between different river systems. 4. Mitochondrial cyt b sequences were used (i) to assess genetic diversity in G. zebratus, P. burchelli and S. capensis from the south-western CFR and (ii) to determine the roles of intrinsic ecological adaptations and extrinsic landscape and climatic changes in promoting genetic diversification and shaping present day distribution patterns of lineages in the three taxa. Marine incursions during periods of major sea-level transgressions are proposed to have isolated populations in upland refugia, thereby driving allopatric divergence in these species. Subsequent connections of rivers during wetter periods and lower sea-levels are proposed to have facilitated post-speciation dispersal of lineages to attain present day distribution patterns. While detailed morphological studies and further genetic analysis are needed to substantiate the taxonomic status of the newly discovered lineages of Galaxias zebratus, Pseudobarbus burchelli and Sandelia capensis, results of the present study indicate that the south-western CFR represents a previously unrecognised centre of freshwater fish diversity and microendemism in the broader Cape Floristic Region. Accurate identification of lineages and comprehensive mapping of their distribution is a fundamental pre-requisite for ecological studies, assessing conservation status and implementation of appropriate conservation measures.
- Full Text:
- Date Issued: 2012
- Authors: Chakona, Albert
- Date: 2012
- Subjects: Freshwater fishes -- South Africa -- Breede River , Freshwater fishes -- South Africa -- Geographical distribution , Freshwater fishes -- Ecology , Feshwater fishes -- Genetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5372 , http://hdl.handle.net/10962/d1015694
- Description: Distribution patterns and levels of genetic diversity in extant taxa are a product of complex palaeogeographic processes and climatic oscillations as well as the species’ intrinsic ecological adaptations. The Cape Floristic Region of South Africa presents a unique system for studying the processes that promote species diversification and distribution patterns. This region has a high degree of endemism of both terrestrial and aquatic biota and is clearly isolated from neighbouring areas by the Cape Fold Mountains and the Great Escarpment. The objective of this study was to firstly examine the ecology of freshwater fishes belonging to the genera Galaxias, Pseudobarbus and Sandelia in the south-western CFR. This was followed by an assessment of the genetic diversity of these taxa. Unique lineages were identified and their distribution was mapped. The work aimed to explore the role of the region’s complex palaeogeographic and climatic history as well as the role of the species’ ecological adaptations in driving lineage diversification and shaping contemporary distribution patterns. The four main components of the study can be summarised as follows: 1. Habitat associations of three widely distributed lineages of Galaxias zebratus Pseudobarbus burchelli and Sandelia capensis were evaluated at multiple localities in minimally disturbed mountain tributaries of the Breede, Duiwenhoks and Goukou River systems. The lineages have distinct habitat associations which were related to differences in their morphological traits. The slender-bodied Galaxias ‘nebula’ and the fusiform-shaped Pseudobarbus ‘Breede’ are capable of exploiting upper reaches with faster water velocity. By contrast, the laterally compressed Sandelia ‘eastern’ is restricted to lower reaches, making this lineage more susceptible to a wide array of impacts. 2. A recently discovered lineage of Galaxias zebratus, (Galaxias ‘nebula’), was found to be capable of tolerating emersion for a prolonged period of time. This is the first time that such capabilities have been documented in an African galaxiid. These adaptations have implications for the interpretation of Galaxias ‘nebula’s wide distribution range. 3. The phylogeography of Galaxias ‘nebula’ across its entire distribution range was investigated using two mitochondrial genes (cytochrome c oxidase subunit I (COI) and cytochrome b (cyt b)). This lineage has a complex evolutionary history that was influenced by both intrinsic and extrinsic factors. Rare events such as episodic drainage connections during Pleistocene and Holocene pluvial periods, possibly augmented by river confluences during periods of lower sea-levels and river capture events seem to be the most credible explanation for the extensive contemporary distribution and the relatively shallow genetic divergence between different river systems. 4. Mitochondrial cyt b sequences were used (i) to assess genetic diversity in G. zebratus, P. burchelli and S. capensis from the south-western CFR and (ii) to determine the roles of intrinsic ecological adaptations and extrinsic landscape and climatic changes in promoting genetic diversification and shaping present day distribution patterns of lineages in the three taxa. Marine incursions during periods of major sea-level transgressions are proposed to have isolated populations in upland refugia, thereby driving allopatric divergence in these species. Subsequent connections of rivers during wetter periods and lower sea-levels are proposed to have facilitated post-speciation dispersal of lineages to attain present day distribution patterns. While detailed morphological studies and further genetic analysis are needed to substantiate the taxonomic status of the newly discovered lineages of Galaxias zebratus, Pseudobarbus burchelli and Sandelia capensis, results of the present study indicate that the south-western CFR represents a previously unrecognised centre of freshwater fish diversity and microendemism in the broader Cape Floristic Region. Accurate identification of lineages and comprehensive mapping of their distribution is a fundamental pre-requisite for ecological studies, assessing conservation status and implementation of appropriate conservation measures.
- Full Text:
- Date Issued: 2012
Development of molecularly imprinted polymer based solid phase extraction sorbents for the selective cleanup of food and pharmaceutical residue samples
- Authors: Batlokwa, Bareki Shima
- Date: 2012
- Subjects: Sorbents -- Research Nanofibers -- Research Aflatoxins -- Research Electrospinning -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4309 , http://hdl.handle.net/10962/d1004967
- Description: This thesis presents the development of chlorophyll, cholic acid, aflatoxin B1 molecularly imprinted polymer (MIP) particles and cholic acid MIP nanofibers for application as selective solid phase extraction (SPE) sorbents. The particles were prepared by bulk polymerization and the nanofibers by a novel approach combining molecular imprinting and electrospinning technology. The AFB1 MIP particles were compared with an aflatoxin specific immunoextraction sorbent in cleaning-up and pre-concentrating aflatoxins from nut extracts. They both recorded high extraction efficiencies (EEs) of > 97 % in selectively extracting the aflatoxins (AFB1, AFB2, AFG1 and AFG2). High reproducibility marked by the low %RSDs of < 1% and low LODs of ≤ 0.02 ng/g were calculated in all cases. The LODs were within the monitoring requirements of the European Commission. The results were validated with a peanut butter certified reference material. The chlorophyll MIP on the other hand selectively removed chlorophyll that would otherwise interfere during pesticide residue analysis (PRA) from > 0.6 to <0.09 Au in green plants extracts. The extracted chlorophyll was removed to far below the level of ≥ 0.399 Au that is usually associated with interference during PRA. Furthermore, the MIP demonstrated better selectivity by removing only chlorophyll (> 99%) in the presence of planar pesticides than the currently employed graphitized carbon black (GCB) that removed both the chlorophyll (> 88%) and planar pesticides (> 89%). For the interfering cholic acid during drug residue analysis, cholic acid MIP electrospun nanofibers demonstrated to be more sensitive and possessing higher loading capacity than the MIP particles. 100% cholic acid was removed by the nanofibers from standard solutions relative to 80% by the particles. This showed that the nanofibers have better performance than the micro particles and as such have potential to replace the particle based SPE sorbents that are currently in use. All the templates were optimally removed from the prepared MIPs by employing a novel pressurized hot water extraction template removal method that was used for the first time in this thesis. The method employed only water, an environmentally friendly solvent to remove templates to ≥ 99.6% with template residual bleeding of ≤ 0.02%.
- Full Text:
- Date Issued: 2012
- Authors: Batlokwa, Bareki Shima
- Date: 2012
- Subjects: Sorbents -- Research Nanofibers -- Research Aflatoxins -- Research Electrospinning -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4309 , http://hdl.handle.net/10962/d1004967
- Description: This thesis presents the development of chlorophyll, cholic acid, aflatoxin B1 molecularly imprinted polymer (MIP) particles and cholic acid MIP nanofibers for application as selective solid phase extraction (SPE) sorbents. The particles were prepared by bulk polymerization and the nanofibers by a novel approach combining molecular imprinting and electrospinning technology. The AFB1 MIP particles were compared with an aflatoxin specific immunoextraction sorbent in cleaning-up and pre-concentrating aflatoxins from nut extracts. They both recorded high extraction efficiencies (EEs) of > 97 % in selectively extracting the aflatoxins (AFB1, AFB2, AFG1 and AFG2). High reproducibility marked by the low %RSDs of < 1% and low LODs of ≤ 0.02 ng/g were calculated in all cases. The LODs were within the monitoring requirements of the European Commission. The results were validated with a peanut butter certified reference material. The chlorophyll MIP on the other hand selectively removed chlorophyll that would otherwise interfere during pesticide residue analysis (PRA) from > 0.6 to <0.09 Au in green plants extracts. The extracted chlorophyll was removed to far below the level of ≥ 0.399 Au that is usually associated with interference during PRA. Furthermore, the MIP demonstrated better selectivity by removing only chlorophyll (> 99%) in the presence of planar pesticides than the currently employed graphitized carbon black (GCB) that removed both the chlorophyll (> 88%) and planar pesticides (> 89%). For the interfering cholic acid during drug residue analysis, cholic acid MIP electrospun nanofibers demonstrated to be more sensitive and possessing higher loading capacity than the MIP particles. 100% cholic acid was removed by the nanofibers from standard solutions relative to 80% by the particles. This showed that the nanofibers have better performance than the micro particles and as such have potential to replace the particle based SPE sorbents that are currently in use. All the templates were optimally removed from the prepared MIPs by employing a novel pressurized hot water extraction template removal method that was used for the first time in this thesis. The method employed only water, an environmentally friendly solvent to remove templates to ≥ 99.6% with template residual bleeding of ≤ 0.02%.
- Full Text:
- Date Issued: 2012
An analysis of the Southern African Development Community (SADC) preventive diplomacy in the kingdom of Lesotho: a case study
- Authors: Bukae, Nkosi Makhonya
- Date: 2012
- Subjects: Southern African Development Community , Diplomatic negotiations in international disputes , Diplomacy , Conflict management -- Lesotho , Africa, Southern -- Politics and government , Lesotho -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8196 , http://hdl.handle.net/10948/d1008296 , Southern African Development Community , Diplomatic negotiations in international disputes , Diplomacy , Conflict management -- Lesotho , Africa, Southern -- Politics and government , Lesotho -- Politics and government
- Description: The focus of this study is the Southern African Development Community (SADC) preventive diplomacy interventions in Lesotho in 1994, 1998 and 2007. The core aim of the study was to evaluate the efficacy of the SADC security mechanism (the Organ on Politics, Defence and Security (OPDS) in conflict prevention, management and resolution on the basis of the Lesotho experience. Data for this qualitative case study was collected through interviews and document analysis. The twenty four participants for the study were drawn from the SADC OPDS unit, Lesotho political parties, Civil Society Organisations (CSOs), Academics from the University of Botswana (UB) and the National University of Lesotho (NUL), retired Botswana Defence officers who participated in the Lesotho missions and office of the post-2007election dispute dialogue facilitator in Lesotho. Documents on the SADC Treaties, Protocols, Communiqués and interventions in other set ups were used to highlight its operational policies, mandate, structures, successes and challenges. Lesotho was chosen as a case study because SADC employed both non-coercive (SADC Troika and Eminent Person mediation, 1994 and 2007 respectively) and coercive measures (the 1998 military intervention). The findings of the study revealed that SADC as a regional body had its own successes and challenges. Different perceptions on the SADC interventions in Lesotho emerged mainly between the participants from the ruling party and the opposition parties. While the former commended SADC for successfully mitigating the calamitous effects of 1994, 1998 and 2007 post-electoral violence, the opposition parties viewed the regional organisations as engaged in illegal interference in the domestic affairs of the country to defend the incumbent governing party. It also emerged from the study that the SADC security mechanism has numerous structural and operational flaws. There were several unanswered questions revolving around the legality and mandate of some of the missions. For instance, no concrete evidence emerged as to whether the 1998 military intervention was authorised by the SADC. The study also revealed that SADC has learnt valuable lessons from the Lesotho missions. Some of the reforms which the SADC has introduced in the OPDS such as the establishment of the SADC Stand by Force, Early Warning structures, the Mediation Unit, and a panel of expert mediators emanated mainly from the Lesotho experiences. The study recommends that SADC needs to harmonise the efforts of its OPDS structures such as the Mediation Unit; the Troika; the Inter-State Defence and Security Committee (ISDSC); the Inter-State Politics and Diplomacy Committee (ISPDC) and the Summit of Heads of States and Governments for rapid, coherent and well coordinated interventions in future regional preventive missions. It is also recommended that SADC should focus on identifying and mitigating underlying causal factors such as underdevelopment; poverty; deprivation of freedoms, marginalisation and other forms of social stratifications and oppression in its preventive diplomacy missions if durable peace is to be achieved in Lesotho and any other future cases.
- Full Text:
- Date Issued: 2012
- Authors: Bukae, Nkosi Makhonya
- Date: 2012
- Subjects: Southern African Development Community , Diplomatic negotiations in international disputes , Diplomacy , Conflict management -- Lesotho , Africa, Southern -- Politics and government , Lesotho -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8196 , http://hdl.handle.net/10948/d1008296 , Southern African Development Community , Diplomatic negotiations in international disputes , Diplomacy , Conflict management -- Lesotho , Africa, Southern -- Politics and government , Lesotho -- Politics and government
- Description: The focus of this study is the Southern African Development Community (SADC) preventive diplomacy interventions in Lesotho in 1994, 1998 and 2007. The core aim of the study was to evaluate the efficacy of the SADC security mechanism (the Organ on Politics, Defence and Security (OPDS) in conflict prevention, management and resolution on the basis of the Lesotho experience. Data for this qualitative case study was collected through interviews and document analysis. The twenty four participants for the study were drawn from the SADC OPDS unit, Lesotho political parties, Civil Society Organisations (CSOs), Academics from the University of Botswana (UB) and the National University of Lesotho (NUL), retired Botswana Defence officers who participated in the Lesotho missions and office of the post-2007election dispute dialogue facilitator in Lesotho. Documents on the SADC Treaties, Protocols, Communiqués and interventions in other set ups were used to highlight its operational policies, mandate, structures, successes and challenges. Lesotho was chosen as a case study because SADC employed both non-coercive (SADC Troika and Eminent Person mediation, 1994 and 2007 respectively) and coercive measures (the 1998 military intervention). The findings of the study revealed that SADC as a regional body had its own successes and challenges. Different perceptions on the SADC interventions in Lesotho emerged mainly between the participants from the ruling party and the opposition parties. While the former commended SADC for successfully mitigating the calamitous effects of 1994, 1998 and 2007 post-electoral violence, the opposition parties viewed the regional organisations as engaged in illegal interference in the domestic affairs of the country to defend the incumbent governing party. It also emerged from the study that the SADC security mechanism has numerous structural and operational flaws. There were several unanswered questions revolving around the legality and mandate of some of the missions. For instance, no concrete evidence emerged as to whether the 1998 military intervention was authorised by the SADC. The study also revealed that SADC has learnt valuable lessons from the Lesotho missions. Some of the reforms which the SADC has introduced in the OPDS such as the establishment of the SADC Stand by Force, Early Warning structures, the Mediation Unit, and a panel of expert mediators emanated mainly from the Lesotho experiences. The study recommends that SADC needs to harmonise the efforts of its OPDS structures such as the Mediation Unit; the Troika; the Inter-State Defence and Security Committee (ISDSC); the Inter-State Politics and Diplomacy Committee (ISPDC) and the Summit of Heads of States and Governments for rapid, coherent and well coordinated interventions in future regional preventive missions. It is also recommended that SADC should focus on identifying and mitigating underlying causal factors such as underdevelopment; poverty; deprivation of freedoms, marginalisation and other forms of social stratifications and oppression in its preventive diplomacy missions if durable peace is to be achieved in Lesotho and any other future cases.
- Full Text:
- Date Issued: 2012
Re-tracing representations and identities in twentieth century South African and African photography: Joseph Denfield, regimes of seeing and alternative visual histories
- Authors: Mnyaka, Phindezwa Elizabeth
- Date: 2012
- Subjects: Historical museums -- South Africa -- Eastern Cape , Natural history , Photography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (History)
- Identifier: vital:11536 , http://hdl.handle.net/10353/540 , Historical museums -- South Africa -- Eastern Cape , Natural history , Photography -- South Africa
- Description: The thesis examines the photographic collection of Joseph Denfield, an archivist and historian who experimented with photography over a twenty-year period. The study is located within the field of critical visual studies that focuses on historical photography in its depiction of identities and groups in the context of social change. The thesis pays attention to the manner and extent to which Denfield participated in regional visual economies at various moments during his photographic career in order to establish his contribution towards a visual history in Africa and more broadly Southern Africa. It follows Denfield’s career trajectory chronologically. It begins with a study of his photographic work in Nigeria which was oriented around so-called ‘pagan tribes’ and which was framed within the discourse of ethnography. It then pays attention to his growth as an artist in photography that resulted from years of exhibiting in salons. I read these photographs and texts in relation to his earlier work in Nigeria given the extent to which he drew on anthropological discourses. It is through his involvement with photographic art circles that Denfield developed as a historian as a result of his research into the history of photography and regional visual histories. This took the form of both unearthing historical photographs as well as photographing historical sites to construct the past in particular ways through the visual. At each stage he translated these histories into public forms of representation and power thus he figures among a small group of ‘colonial’ photographers that shaped the visual economy of Southern Africa. Through a detailed study of his work, the thesis thus aims to re-think through new dimensions of visual culture.
- Full Text:
- Date Issued: 2012
- Authors: Mnyaka, Phindezwa Elizabeth
- Date: 2012
- Subjects: Historical museums -- South Africa -- Eastern Cape , Natural history , Photography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (History)
- Identifier: vital:11536 , http://hdl.handle.net/10353/540 , Historical museums -- South Africa -- Eastern Cape , Natural history , Photography -- South Africa
- Description: The thesis examines the photographic collection of Joseph Denfield, an archivist and historian who experimented with photography over a twenty-year period. The study is located within the field of critical visual studies that focuses on historical photography in its depiction of identities and groups in the context of social change. The thesis pays attention to the manner and extent to which Denfield participated in regional visual economies at various moments during his photographic career in order to establish his contribution towards a visual history in Africa and more broadly Southern Africa. It follows Denfield’s career trajectory chronologically. It begins with a study of his photographic work in Nigeria which was oriented around so-called ‘pagan tribes’ and which was framed within the discourse of ethnography. It then pays attention to his growth as an artist in photography that resulted from years of exhibiting in salons. I read these photographs and texts in relation to his earlier work in Nigeria given the extent to which he drew on anthropological discourses. It is through his involvement with photographic art circles that Denfield developed as a historian as a result of his research into the history of photography and regional visual histories. This took the form of both unearthing historical photographs as well as photographing historical sites to construct the past in particular ways through the visual. At each stage he translated these histories into public forms of representation and power thus he figures among a small group of ‘colonial’ photographers that shaped the visual economy of Southern Africa. Through a detailed study of his work, the thesis thus aims to re-think through new dimensions of visual culture.
- Full Text:
- Date Issued: 2012
Dreams, sexuality and fantasy: a psychoanalytic reading of K. Sello Duiker’s novels
- Authors: Kirton-Els, Teneille
- Date: 2012
- Language: English
- Type: Thesis , Doctoral , DLitt et Phil
- Identifier: vital:11890 , http://hdl.handle.net/10353/d1020154
- Description: The primary aim of this thesis is to provide a text-based literary study exploring the characters and themes created by K. Sello Duiker in the three novels, Thirteen Cents, The Quiet Violence of Dreams and The Hidden Star. Duiker’s work is significant because it highlights prominent societal challenges prevalent in post-apartheid society. By analysing Duiker’s novels one acquires a better understanding of this author, an understanding of the world that contributed to the creation of his texts and his contribution to South African literature. Insight into Duiker’s fictional world allows for a careful investigation of the prominent societal issues prevalent in Duiker’s work - a world riddled with violence, issues of sexuality and psychological distress. For this purpose this thesis is premised on the notion that underpinning K. Sello Duiker’s oeuvre is a central focus on dreams, sexuality and fantasy. Logically, therefore, the main focus of the study is specifically on the inner working of the characters’ minds and how they deal/ or are unable to cope with contemporary social concerns, often resulting in psychological turmoil and dysfunctionality. For this reason, prominent themes examined in this study are the interpretation of dreams, an exploration of sexuality and an examination of fantasy in the three novels. Psychoanalytic literary theory, with the main focus being specifically on the theories presented by Sigmund Freud is used as an analytic tool to read Duiker’s texts. Psychoanalytic theory is arguably the most appropriate for analysing Duiker’s novels as it allows one to investigate the characters’ psyches and the psychological effect of societal influences on these characters. In addition, one is also able to examine how the characters are able/ unable to deal with the trauma caused by the contemporary issues in society – issues of violence, sexuality and psychological distress. Thus, one is able to grasp an overall understanding of the characters’ behaviour and actions. Furthermore, the characters’ experiences are based on the behaviour and incidents of real people, people suffering from psychological dysfunctionality, sexuality issues and identity crisis. The first chapter discusses post-apartheid literature, and provides a brief background on Duiker, his works and his conception as a writer. Chapter two provides an overview of psychoanalytic theory and on the relevant theories of Sigmund Freud. Chapter three offers a reading of Thirteen Cents, a novel that pays particular attention to the lives of children living on the streets of Cape Town. In the next chapter The Quiet Violence of Dreams is examined with a special focus on Duiker’s experimentation with form in the construction of this novel. Aspects pertaining to sexuality and dreams are also examined. Chapter five pays particular attention to magical realism and fantasy in The Hidden Star.
- Full Text:
- Date Issued: 2012
- Authors: Kirton-Els, Teneille
- Date: 2012
- Language: English
- Type: Thesis , Doctoral , DLitt et Phil
- Identifier: vital:11890 , http://hdl.handle.net/10353/d1020154
- Description: The primary aim of this thesis is to provide a text-based literary study exploring the characters and themes created by K. Sello Duiker in the three novels, Thirteen Cents, The Quiet Violence of Dreams and The Hidden Star. Duiker’s work is significant because it highlights prominent societal challenges prevalent in post-apartheid society. By analysing Duiker’s novels one acquires a better understanding of this author, an understanding of the world that contributed to the creation of his texts and his contribution to South African literature. Insight into Duiker’s fictional world allows for a careful investigation of the prominent societal issues prevalent in Duiker’s work - a world riddled with violence, issues of sexuality and psychological distress. For this purpose this thesis is premised on the notion that underpinning K. Sello Duiker’s oeuvre is a central focus on dreams, sexuality and fantasy. Logically, therefore, the main focus of the study is specifically on the inner working of the characters’ minds and how they deal/ or are unable to cope with contemporary social concerns, often resulting in psychological turmoil and dysfunctionality. For this reason, prominent themes examined in this study are the interpretation of dreams, an exploration of sexuality and an examination of fantasy in the three novels. Psychoanalytic literary theory, with the main focus being specifically on the theories presented by Sigmund Freud is used as an analytic tool to read Duiker’s texts. Psychoanalytic theory is arguably the most appropriate for analysing Duiker’s novels as it allows one to investigate the characters’ psyches and the psychological effect of societal influences on these characters. In addition, one is also able to examine how the characters are able/ unable to deal with the trauma caused by the contemporary issues in society – issues of violence, sexuality and psychological distress. Thus, one is able to grasp an overall understanding of the characters’ behaviour and actions. Furthermore, the characters’ experiences are based on the behaviour and incidents of real people, people suffering from psychological dysfunctionality, sexuality issues and identity crisis. The first chapter discusses post-apartheid literature, and provides a brief background on Duiker, his works and his conception as a writer. Chapter two provides an overview of psychoanalytic theory and on the relevant theories of Sigmund Freud. Chapter three offers a reading of Thirteen Cents, a novel that pays particular attention to the lives of children living on the streets of Cape Town. In the next chapter The Quiet Violence of Dreams is examined with a special focus on Duiker’s experimentation with form in the construction of this novel. Aspects pertaining to sexuality and dreams are also examined. Chapter five pays particular attention to magical realism and fantasy in The Hidden Star.
- Full Text:
- Date Issued: 2012
The competitiveness of the South African citrus industry in the face of the changing global health and environmental standards
- Authors: Ndou, Portia
- Date: 2012
- Subjects: Citrus fruit industry -- South Africa , Food industry and trade -- Safety regulations , Agricultural industries -- Safety regulations , Food -- Safety measures -- International cooperation , Export marketing -- Law and legislation -- South Africa , Competition, International
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11162 , http://hdl.handle.net/10353/477 , Citrus fruit industry -- South Africa , Food industry and trade -- Safety regulations , Agricultural industries -- Safety regulations , Food -- Safety measures -- International cooperation , Export marketing -- Law and legislation -- South Africa , Competition, International
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2012
- Authors: Ndou, Portia
- Date: 2012
- Subjects: Citrus fruit industry -- South Africa , Food industry and trade -- Safety regulations , Agricultural industries -- Safety regulations , Food -- Safety measures -- International cooperation , Export marketing -- Law and legislation -- South Africa , Competition, International
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11162 , http://hdl.handle.net/10353/477 , Citrus fruit industry -- South Africa , Food industry and trade -- Safety regulations , Agricultural industries -- Safety regulations , Food -- Safety measures -- International cooperation , Export marketing -- Law and legislation -- South Africa , Competition, International
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2012
Creating a space for integrative education within the sciences
- Authors: Van der Post, Leda
- Date: 2012
- Subjects: Computer science -- Vocational guidance , Education, Cooperative , Curriculum evaluation , Experiential learning -- Science
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10482 , http://hdl.handle.net/10948/d1012677 , Computer science -- Vocational guidance , Education, Cooperative , Curriculum evaluation , Experiential learning -- Science
- Description: This thesis documents an action research project that was carried out within the Department of Computing Sciences at the Nelson Mandela Metropolitan University (NMMU), South Africa, from January 2010 to December 2011. The overall aim of the research was to foster an environment in which academics could explore ways to teach using an integrative approach to education. Previous research within the department had raised the concern that students were graduating without the type of high-level cognitive skills that were required in the workplace. While the students’ technical skills were perceived as being excellent, employers indicated that students would benefit from opportunities to develop or improve skills such as communication, teamwork, innovative thinking and time management. These skills include high-level cognitive skills, and are often referred to as “soft skills”. The academics participating in the research project came to believe that it was essential to develop teaching methods that would provide opportunities for students to develop these soft skills, in conjunction with the content and technical knowledge currently addressed in their courses. The research project followed the living theory approach to action research. A living theory action research project allows the researcher to investigate her own teaching, and develop a theory of practice. The theory of practice can be applied to the issues under investigation, to improve the situation or solve problems. At the same time, the theory of practice can contribute to the body of knowledge within the academic domain of the research. Action research is an iterative, cyclical process. There were four research cycles, each one semester in length, during the two years of the project. The project will continue, with a fifth research cycle, starting in January 2012. By the end of the fourth research cycle—Semester Two, 2011—there were eleven academics actively participating in the research group. The project had extended its influence to include academics from the Department of Mathematics at NMMU. The academics ranged from senior, long-serving professors to junior lecturing staff. The results of the research, or the researcher-practitioner’s living theory, explain the process by which an effective and enthusiastic community of practice, dedicated to improving the academics’ teaching and learning practice, was developed. The living theory is applicable to academics within a scientific discipline, desiring to explore and improve their education practice. My living theory explains the characteristics of the TLC (The Learning Community) space, and the action strategies for creating such a space. The explanation of the process of this project includes an analysis of the development process of the research group, typical characteristics of the environment or “space” of the group, and action strategies that other academics could use to create a similar community of practice.
- Full Text:
- Date Issued: 2012
- Authors: Van der Post, Leda
- Date: 2012
- Subjects: Computer science -- Vocational guidance , Education, Cooperative , Curriculum evaluation , Experiential learning -- Science
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10482 , http://hdl.handle.net/10948/d1012677 , Computer science -- Vocational guidance , Education, Cooperative , Curriculum evaluation , Experiential learning -- Science
- Description: This thesis documents an action research project that was carried out within the Department of Computing Sciences at the Nelson Mandela Metropolitan University (NMMU), South Africa, from January 2010 to December 2011. The overall aim of the research was to foster an environment in which academics could explore ways to teach using an integrative approach to education. Previous research within the department had raised the concern that students were graduating without the type of high-level cognitive skills that were required in the workplace. While the students’ technical skills were perceived as being excellent, employers indicated that students would benefit from opportunities to develop or improve skills such as communication, teamwork, innovative thinking and time management. These skills include high-level cognitive skills, and are often referred to as “soft skills”. The academics participating in the research project came to believe that it was essential to develop teaching methods that would provide opportunities for students to develop these soft skills, in conjunction with the content and technical knowledge currently addressed in their courses. The research project followed the living theory approach to action research. A living theory action research project allows the researcher to investigate her own teaching, and develop a theory of practice. The theory of practice can be applied to the issues under investigation, to improve the situation or solve problems. At the same time, the theory of practice can contribute to the body of knowledge within the academic domain of the research. Action research is an iterative, cyclical process. There were four research cycles, each one semester in length, during the two years of the project. The project will continue, with a fifth research cycle, starting in January 2012. By the end of the fourth research cycle—Semester Two, 2011—there were eleven academics actively participating in the research group. The project had extended its influence to include academics from the Department of Mathematics at NMMU. The academics ranged from senior, long-serving professors to junior lecturing staff. The results of the research, or the researcher-practitioner’s living theory, explain the process by which an effective and enthusiastic community of practice, dedicated to improving the academics’ teaching and learning practice, was developed. The living theory is applicable to academics within a scientific discipline, desiring to explore and improve their education practice. My living theory explains the characteristics of the TLC (The Learning Community) space, and the action strategies for creating such a space. The explanation of the process of this project includes an analysis of the development process of the research group, typical characteristics of the environment or “space” of the group, and action strategies that other academics could use to create a similar community of practice.
- Full Text:
- Date Issued: 2012