The labour market drop-out rate : a new approach to estimating the returns to government investment in higher education : the case for marine science in South Africa
- Authors: Grootes, Pieter Brian
- Date: 2005
- Subjects: Labor market Marine scientists -- South Africa Education -- Economic aspects -- South Africa Higher education and state -- South Africa Education -- Social aspects Human capital -- South Africa Education, Higher -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:950 , http://hdl.handle.net/10962/d1002684
- Description: The private and social returns to education literature share the same conclusion: that education is beneficial for both the individual and society. However, the theoretical underpinnings are flawed as the literature does not account for the main feature that leads to the acquisition of education: the private demand for education. An understanding of the factors that motivate the individual to invest in education would lead to a deeper insight as to why both private and social returns to education exist, and would provide a clearer framework on which to base the government funding of education. This thesis provides a first attempt at filling this gap by introducing a method of estimating the returns to government investment in education, which is labelled the ‘labour market drop-out rate approach’. The approach focuses on the social return to education, not in terms of graduate earnings, but in terms of the interaction of the graduate with the economy. The approach introduces a measure of expertise utilisation, based on the premise that there is no social return to an individual acquiring education if he or she does not utilise the acquired knowledge base on entering the labour market. The approach is tested using the labour market for marine scientists in South Africa as a case study. In this case the private demand for education is found to be heavily influenced by the provision of student bursaries from the National Research Foundation, with a resulting estimate of the social return to a degree in marine science being a mere 20% to 25%. Owing to this, a new approach to government investment in marine science is introduced, that of graduate contribution schemes. Of broader significance is the ease of application of this approach, it may be adopted to analyse any funding programme in which a government may decide to invest. As such, the labour market drop-out rate provides an extension to the returns to education literature through its theoretical dealings of the private demand for education, as well as a practical tool which government agencies can use to evaluate the efficacy of any government funding of education.
- Full Text:
- Date Issued: 2005
- Authors: Grootes, Pieter Brian
- Date: 2005
- Subjects: Labor market Marine scientists -- South Africa Education -- Economic aspects -- South Africa Higher education and state -- South Africa Education -- Social aspects Human capital -- South Africa Education, Higher -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:950 , http://hdl.handle.net/10962/d1002684
- Description: The private and social returns to education literature share the same conclusion: that education is beneficial for both the individual and society. However, the theoretical underpinnings are flawed as the literature does not account for the main feature that leads to the acquisition of education: the private demand for education. An understanding of the factors that motivate the individual to invest in education would lead to a deeper insight as to why both private and social returns to education exist, and would provide a clearer framework on which to base the government funding of education. This thesis provides a first attempt at filling this gap by introducing a method of estimating the returns to government investment in education, which is labelled the ‘labour market drop-out rate approach’. The approach focuses on the social return to education, not in terms of graduate earnings, but in terms of the interaction of the graduate with the economy. The approach introduces a measure of expertise utilisation, based on the premise that there is no social return to an individual acquiring education if he or she does not utilise the acquired knowledge base on entering the labour market. The approach is tested using the labour market for marine scientists in South Africa as a case study. In this case the private demand for education is found to be heavily influenced by the provision of student bursaries from the National Research Foundation, with a resulting estimate of the social return to a degree in marine science being a mere 20% to 25%. Owing to this, a new approach to government investment in marine science is introduced, that of graduate contribution schemes. Of broader significance is the ease of application of this approach, it may be adopted to analyse any funding programme in which a government may decide to invest. As such, the labour market drop-out rate provides an extension to the returns to education literature through its theoretical dealings of the private demand for education, as well as a practical tool which government agencies can use to evaluate the efficacy of any government funding of education.
- Full Text:
- Date Issued: 2005
A decade of changes Eastern Cape white commercial farmers' discourses of democracy
- Authors: Böhmke, Werner
- Date: 2005
- Subjects: Farmers -- Psychology , Agriculture -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Democracy -- South Africa -- Eastern Cape , Political culture -- South Africa -- Eastern Cape , Social psychology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2934 , http://hdl.handle.net/10962/d1002443 , Farmers -- Psychology , Agriculture -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Democracy -- South Africa -- Eastern Cape , Political culture -- South Africa -- Eastern Cape , Social psychology -- South Africa -- Eastern Cape
- Description: This paper deals with an analysis of the discursive accounts of Eastern Cape white commercial farmers on the subject of Democracy. Drawing on the theoretical perspectives of Social Constructionism and Discourse Analysis – which view individuals’ accounts of their realities as produced and informed by their particular social and historical context – the paper seeks to provide an analysis of the content of, and rhetorical strategies within the participants’ accounts and explanations. Such accounts of the social, historical and political circumstances in which Eastern Cape commercial farmers find themselves are thought to provide valuable insights into the manner in which the process of democratisation has been received by members of the agricultural sector. Data collection was conducted via brief, audio taped, semi-structured interviews. The participants were all white men and women, living in a commercial farming region of the Eastern Cape Province. Responses to the interviews were subjected to the Discourse Analytical procedure advanced by Ian Parker. Analyses reveal that participants are critical of the notion of democracy; utilize specific rhetorical and argumentation strategies; make use of notions and techniques of ‘Othering’; and subscribe to a colonial / patriarchal ideology which attempts to idealize pre-democratic South Africa. These findings illustrate what is in many ways still an ongoing political and ideological struggle in the rural regions of the country.
- Full Text:
- Date Issued: 2005
- Authors: Böhmke, Werner
- Date: 2005
- Subjects: Farmers -- Psychology , Agriculture -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Democracy -- South Africa -- Eastern Cape , Political culture -- South Africa -- Eastern Cape , Social psychology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2934 , http://hdl.handle.net/10962/d1002443 , Farmers -- Psychology , Agriculture -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Democracy -- South Africa -- Eastern Cape , Political culture -- South Africa -- Eastern Cape , Social psychology -- South Africa -- Eastern Cape
- Description: This paper deals with an analysis of the discursive accounts of Eastern Cape white commercial farmers on the subject of Democracy. Drawing on the theoretical perspectives of Social Constructionism and Discourse Analysis – which view individuals’ accounts of their realities as produced and informed by their particular social and historical context – the paper seeks to provide an analysis of the content of, and rhetorical strategies within the participants’ accounts and explanations. Such accounts of the social, historical and political circumstances in which Eastern Cape commercial farmers find themselves are thought to provide valuable insights into the manner in which the process of democratisation has been received by members of the agricultural sector. Data collection was conducted via brief, audio taped, semi-structured interviews. The participants were all white men and women, living in a commercial farming region of the Eastern Cape Province. Responses to the interviews were subjected to the Discourse Analytical procedure advanced by Ian Parker. Analyses reveal that participants are critical of the notion of democracy; utilize specific rhetorical and argumentation strategies; make use of notions and techniques of ‘Othering’; and subscribe to a colonial / patriarchal ideology which attempts to idealize pre-democratic South Africa. These findings illustrate what is in many ways still an ongoing political and ideological struggle in the rural regions of the country.
- Full Text:
- Date Issued: 2005
An investigation into the possible neuroprotective or neurotoxic properties of metrifonate
- Authors: Ramsunder, Adrusha
- Date: 2005 , 2013-06-11
- Subjects: Nervous system -- Degeneration -- Treatment , Neurotoxic agents , Alzheimer's disease -- Treatment , Metrifonate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3833 , http://hdl.handle.net/10962/d1007560 , Nervous system -- Degeneration -- Treatment , Neurotoxic agents , Alzheimer's disease -- Treatment , Metrifonate
- Description: Alzheimer's disease is a progressive neurodegenerative disorder, in which there is a marked decline in neurotransmitters, especially those of the cholinergic pathways. One of the approaches to the symptomatic treatment of Alzheimer's disease is the inhibition of the breakdown of the neurotransmitter acetylcholine, using an acetylcholinesterase inhibitor. One such drug tested, is the organophosphate, metrifonate. Any drug used for the treatment of neurodegenerative disorders should preferably not induce further neurological damage. Thus, in the present study, we investigated whether or not metrifonate is neuroprotective. The in vivo and in vitro effect of this drug on free radicals generation shows that metrifonate increases the level ofthese reactive species. Lipid peroxidation induced using quinolinic acid (QA) and iron (II) and show that metrifonate increased the peroxidative damage induced by using quinolinic acid. Metrifonate is also able to induce lipid peroxidation both in vivo and in vitro. This was reduced in vitro in the presence of melatonin. Using iron (II), in vi/ro, there was no significant difference in the level of lipid peroxidation in the presence of this drug. An investigation of the activity of the mitochondrial electron transport chain and complex I of the electron transport chain in the presence of metrifonate revealed that metrifonate reduces the activity of the electron transport chain at the level of complex I. The activity of the mitochondrial electron transport chain was restored in the presence of melatonin. Pineal organ culture showed that metrifonate does not increase melatonin production. Histological and apoptosis studies show that tissue necrosis and apoptosis respectively, occur in the presence of this agent, which is reduced in the presence of melatonin. Metal binding studies were performed USing ultraviolet spectroscopy, and electrochemical analysis to examine the interaction of metrifonate with iron (II) and iron (III). No shift in the peak was observed in the ultraviolet spectrum when iron (ll) was added to metrifonate. Electrochemical studies show that there may be a very weak or no ligand formed between the metal and drug. This study shows that while drugs such as metrifonate may be beneficial in restoring cognitive function in Alzheimer's disease, it could also have the potential to enhance neurodegeneration, thus worsening the condition, in the long term. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2005
- Authors: Ramsunder, Adrusha
- Date: 2005 , 2013-06-11
- Subjects: Nervous system -- Degeneration -- Treatment , Neurotoxic agents , Alzheimer's disease -- Treatment , Metrifonate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3833 , http://hdl.handle.net/10962/d1007560 , Nervous system -- Degeneration -- Treatment , Neurotoxic agents , Alzheimer's disease -- Treatment , Metrifonate
- Description: Alzheimer's disease is a progressive neurodegenerative disorder, in which there is a marked decline in neurotransmitters, especially those of the cholinergic pathways. One of the approaches to the symptomatic treatment of Alzheimer's disease is the inhibition of the breakdown of the neurotransmitter acetylcholine, using an acetylcholinesterase inhibitor. One such drug tested, is the organophosphate, metrifonate. Any drug used for the treatment of neurodegenerative disorders should preferably not induce further neurological damage. Thus, in the present study, we investigated whether or not metrifonate is neuroprotective. The in vivo and in vitro effect of this drug on free radicals generation shows that metrifonate increases the level ofthese reactive species. Lipid peroxidation induced using quinolinic acid (QA) and iron (II) and show that metrifonate increased the peroxidative damage induced by using quinolinic acid. Metrifonate is also able to induce lipid peroxidation both in vivo and in vitro. This was reduced in vitro in the presence of melatonin. Using iron (II), in vi/ro, there was no significant difference in the level of lipid peroxidation in the presence of this drug. An investigation of the activity of the mitochondrial electron transport chain and complex I of the electron transport chain in the presence of metrifonate revealed that metrifonate reduces the activity of the electron transport chain at the level of complex I. The activity of the mitochondrial electron transport chain was restored in the presence of melatonin. Pineal organ culture showed that metrifonate does not increase melatonin production. Histological and apoptosis studies show that tissue necrosis and apoptosis respectively, occur in the presence of this agent, which is reduced in the presence of melatonin. Metal binding studies were performed USing ultraviolet spectroscopy, and electrochemical analysis to examine the interaction of metrifonate with iron (II) and iron (III). No shift in the peak was observed in the ultraviolet spectrum when iron (ll) was added to metrifonate. Electrochemical studies show that there may be a very weak or no ligand formed between the metal and drug. This study shows that while drugs such as metrifonate may be beneficial in restoring cognitive function in Alzheimer's disease, it could also have the potential to enhance neurodegeneration, thus worsening the condition, in the long term. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2005
The feeding ecology, habitat selection and hunting behaviour of re-introduced cheetah on Kwandwe Private Game Reserve, Eastern Cape Province
- Authors: Bissett, Charlene
- Date: 2005
- Subjects: Kwandwe Game Reserve (South Africa) , Cheetah -- Behavior -- South Africa -- Eastern Cape , Cheetah -- Nutrition -- South Africa -- Eastern Cape , Cheetah -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5698 , http://hdl.handle.net/10962/d1005384 , Kwandwe Game Reserve (South Africa) , Cheetah -- Behavior -- South Africa -- Eastern Cape , Cheetah -- Nutrition -- South Africa -- Eastern Cape , Cheetah -- South Africa -- Eastern Cape
- Description: The re-introduction of cheetah onto small reserves in the Eastern Cape Province has created the opportunity to study this species in an environment (Valley Bushveld) in which it has not previously been studied and which is quite different from the less wooded habitats in which previous studies have occurred. Thus the aim of this study is to add to the growing number of studies of cheetah in more wooded habitats and to contribute a better understanding of the level of specialization or adaptability in space use, habitat selection, diet and hunting behaviour that the cheetah possesses. The research was conducted on Kwandwe Private Game Reserve from February 2003 to August 2004. Direct observations, scat analysis and continuous observations were used to avoid bias towards large sized prey found when only using direct observations to study diet. The cheetah killed 15 species and four of the five most important prey species (kudu, springbok, grey duiker and bushbuck) were hunted according to their abundance on the reserve, while impala, the fifth most important prey species, was avoided (i.e. preference index less than one) by the cheetah. The cheetah’s main prey was medium sized ungulates, although the three male coalition killed larger prey than females and females with cubs. The daily food intake per cheetah per day was calculated to range from 5.3kg/cheetah/day for the coalition to 8kg/cheetah/day for a solitary female. Home range areas ranged from 11.1 km² for female cheetah with cubs in a den to 65.6 km² for single female cheetah and core areas ranged from 6 km² for the three male coalition to 26.5 km² for independent cubs. Habitat selection by cheetah on Kwandwe varied between the social groups depending on their susceptibility to predation by lions, their need for cover and need for water, and was similar to what has been previously reported. The home range of the coalition incorporated the most open vegetation type (karroid shrubland) with surrounding denser vegetation, while females occupied areas of denser vegetation. Activity patterns and hunting behaviour varied between different cheetah social groups with female cheetah being more active during day light hours compared to males which made 38% of their kills after dark. The average chase distances for the various cheetah groups varied considerably, and the chase distance for successful hunts was longer than for unsuccessful for all groups except single female cheetah. The percentage of kills’ kleptoparasitised on Kwandwe was very low compared to other studies possibly due to the low density of direct competitors, which in turn lead to longer mean kill retention times. These results suggest that cheetah are more adaptable than previously thought and this adaptability may have important implications for their conservation.
- Full Text:
- Date Issued: 2005
- Authors: Bissett, Charlene
- Date: 2005
- Subjects: Kwandwe Game Reserve (South Africa) , Cheetah -- Behavior -- South Africa -- Eastern Cape , Cheetah -- Nutrition -- South Africa -- Eastern Cape , Cheetah -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5698 , http://hdl.handle.net/10962/d1005384 , Kwandwe Game Reserve (South Africa) , Cheetah -- Behavior -- South Africa -- Eastern Cape , Cheetah -- Nutrition -- South Africa -- Eastern Cape , Cheetah -- South Africa -- Eastern Cape
- Description: The re-introduction of cheetah onto small reserves in the Eastern Cape Province has created the opportunity to study this species in an environment (Valley Bushveld) in which it has not previously been studied and which is quite different from the less wooded habitats in which previous studies have occurred. Thus the aim of this study is to add to the growing number of studies of cheetah in more wooded habitats and to contribute a better understanding of the level of specialization or adaptability in space use, habitat selection, diet and hunting behaviour that the cheetah possesses. The research was conducted on Kwandwe Private Game Reserve from February 2003 to August 2004. Direct observations, scat analysis and continuous observations were used to avoid bias towards large sized prey found when only using direct observations to study diet. The cheetah killed 15 species and four of the five most important prey species (kudu, springbok, grey duiker and bushbuck) were hunted according to their abundance on the reserve, while impala, the fifth most important prey species, was avoided (i.e. preference index less than one) by the cheetah. The cheetah’s main prey was medium sized ungulates, although the three male coalition killed larger prey than females and females with cubs. The daily food intake per cheetah per day was calculated to range from 5.3kg/cheetah/day for the coalition to 8kg/cheetah/day for a solitary female. Home range areas ranged from 11.1 km² for female cheetah with cubs in a den to 65.6 km² for single female cheetah and core areas ranged from 6 km² for the three male coalition to 26.5 km² for independent cubs. Habitat selection by cheetah on Kwandwe varied between the social groups depending on their susceptibility to predation by lions, their need for cover and need for water, and was similar to what has been previously reported. The home range of the coalition incorporated the most open vegetation type (karroid shrubland) with surrounding denser vegetation, while females occupied areas of denser vegetation. Activity patterns and hunting behaviour varied between different cheetah social groups with female cheetah being more active during day light hours compared to males which made 38% of their kills after dark. The average chase distances for the various cheetah groups varied considerably, and the chase distance for successful hunts was longer than for unsuccessful for all groups except single female cheetah. The percentage of kills’ kleptoparasitised on Kwandwe was very low compared to other studies possibly due to the low density of direct competitors, which in turn lead to longer mean kill retention times. These results suggest that cheetah are more adaptable than previously thought and this adaptability may have important implications for their conservation.
- Full Text:
- Date Issued: 2005
Effective management of an information technology professional's career
- Authors: Tedder, Derek
- Date: 2005
- Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
- Full Text:
- Date Issued: 2005
- Authors: Tedder, Derek
- Date: 2005
- Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
- Full Text:
- Date Issued: 2005
Synthesis and electrocatalytic properties of polymerizable metallophthalocyanines
- Authors: Obirai, Joseph Chinye
- Date: 2005
- Subjects: Phthalocyanines Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4447 , http://hdl.handle.net/10962/d1007733
- Description: The syntheses, spectral and electrochemical characterization of new family electropolymerizable pyrrole, thiophene and mercaptopyrimidin substituted metallophthalocyanine (MPc) complexes are described. Tetraamino substituted chromium and manganese phthalocyanine complexes were also synthesized and characterized. The spectral and electrochemical results are comparable to literature reports. The complexes formed stable films when deposited on electrode surfaces. The MPc films were formed by electropolymerization, drop-dry method and self-assembling. Nickel hydroxide-like electrodes were formed by electrotransformation of nickel-tetra-4- (pyrrol-1-yl)phenoxy phthalocyanine polymer films to the corresponding PcNi-O-NiPc modified electrodes in alkaline solution. The thiophene, mercaptopyrimidine functionalized MPcs and amino group containing complexes formed good self-assembled monolayers (SAMs) on gold electrode. The electrode modification processes were reproducible. The conductivities of the electrode were dependent on the surface concentrations of the complexes as a function of electropolymerization scan numbers. The electrodes showed good catalytic responses toward L-cysteine, nitrite, nitric oxide (NO), glycine, phenol and its derivative and oxygen. The results also suggest that the presence of thio groups on the ring substituents lowers the oxidation potential of Lcysteine more compared to literature values. The stability of the amperometric responses toward the various analytes is used to diagnose the applicability of the materials for electroanalytical purposes. The limits of detection for L-cysteine, nitrite, NO and glycine were in the range of ~10⁻⁷ to 10⁻⁵ mol dm⁻³.
- Full Text:
- Date Issued: 2005
- Authors: Obirai, Joseph Chinye
- Date: 2005
- Subjects: Phthalocyanines Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4447 , http://hdl.handle.net/10962/d1007733
- Description: The syntheses, spectral and electrochemical characterization of new family electropolymerizable pyrrole, thiophene and mercaptopyrimidin substituted metallophthalocyanine (MPc) complexes are described. Tetraamino substituted chromium and manganese phthalocyanine complexes were also synthesized and characterized. The spectral and electrochemical results are comparable to literature reports. The complexes formed stable films when deposited on electrode surfaces. The MPc films were formed by electropolymerization, drop-dry method and self-assembling. Nickel hydroxide-like electrodes were formed by electrotransformation of nickel-tetra-4- (pyrrol-1-yl)phenoxy phthalocyanine polymer films to the corresponding PcNi-O-NiPc modified electrodes in alkaline solution. The thiophene, mercaptopyrimidine functionalized MPcs and amino group containing complexes formed good self-assembled monolayers (SAMs) on gold electrode. The electrode modification processes were reproducible. The conductivities of the electrode were dependent on the surface concentrations of the complexes as a function of electropolymerization scan numbers. The electrodes showed good catalytic responses toward L-cysteine, nitrite, nitric oxide (NO), glycine, phenol and its derivative and oxygen. The results also suggest that the presence of thio groups on the ring substituents lowers the oxidation potential of Lcysteine more compared to literature values. The stability of the amperometric responses toward the various analytes is used to diagnose the applicability of the materials for electroanalytical purposes. The limits of detection for L-cysteine, nitrite, NO and glycine were in the range of ~10⁻⁷ to 10⁻⁵ mol dm⁻³.
- Full Text:
- Date Issued: 2005
Developing strategies for creating an environmental focus in a school: narrating the change process
- Authors: Hope, Megan Samantha
- Date: 2005
- Subjects: Environmental education Educational change School environment
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1946 , http://hdl.handle.net/10962/d1008093
- Description: Effective environmental education goes beyond raising environmental awareness and developing positive environmental values, to the encouragement of personal responsibility and action in response to contextual environmental issues in particular. The whole school approach has been advocated as the best approach to environmental education, based on the assumption that the values and attitudes espoused in the classroom need to be reflected in the day-to-day school practice. By practising what they teach, schools reinforce values with action. In contrast, inconsistencies between the formal and non-formal curriculum may lead young people to question the integrity of their teachers or condition them to accept such inconsistencies as cultural and social norms, which in turn may lead to apathy about the environment. Adjustments to the ethos of a school to foreground the environment, both within the curriculum , the management of the school and the behaviour of teachers, pupils and support staff, is not a straightforward undertaking. Institutional factors influence the change process in schools and each school presents a unique context. It is, therefore, difficult to develop a general strategy for the evolution of an environmental ethos. This case study narrates an attempt to implement a change towards an improved environmental focus in a school, and focuses on developing an understanding of how available resources can assist this process while engaging with complexity of change.
- Full Text:
- Date Issued: 2005
- Authors: Hope, Megan Samantha
- Date: 2005
- Subjects: Environmental education Educational change School environment
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1946 , http://hdl.handle.net/10962/d1008093
- Description: Effective environmental education goes beyond raising environmental awareness and developing positive environmental values, to the encouragement of personal responsibility and action in response to contextual environmental issues in particular. The whole school approach has been advocated as the best approach to environmental education, based on the assumption that the values and attitudes espoused in the classroom need to be reflected in the day-to-day school practice. By practising what they teach, schools reinforce values with action. In contrast, inconsistencies between the formal and non-formal curriculum may lead young people to question the integrity of their teachers or condition them to accept such inconsistencies as cultural and social norms, which in turn may lead to apathy about the environment. Adjustments to the ethos of a school to foreground the environment, both within the curriculum , the management of the school and the behaviour of teachers, pupils and support staff, is not a straightforward undertaking. Institutional factors influence the change process in schools and each school presents a unique context. It is, therefore, difficult to develop a general strategy for the evolution of an environmental ethos. This case study narrates an attempt to implement a change towards an improved environmental focus in a school, and focuses on developing an understanding of how available resources can assist this process while engaging with complexity of change.
- Full Text:
- Date Issued: 2005
Rainfall variability in Southern Africa, its influences on streamflow variations and its relationships with climatic variations
- Authors: Valimba, Patrick
- Date: 2005
- Subjects: Rain and rainfall -- Africa, Southern Climatic changes -- Africa, Southern Streamflow -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6030 , http://hdl.handle.net/10962/d1006159
- Description: Hydrological variability involving rainfall and streamflows in southern Africa have been often studied separately or have used cumulative rainfall and streamflow indices. The main objective of this study was to investigate spatio-temporal variations of rainfall, their influences on streamflows and their relationships with climatic variations with emphasis on indices that characterise the hydrological extremes, floods and droughts. It was found that 60-70% of the time when it rains, daily rainfalls are below their long-term averages and daily amounts below 10 mm are the most frequent in southern Africa. Spatially, climatologies of rainfall sub-divided the southern African subcontinent into the dry western/southwestern part and the “humid” eastern and northern part. The daily amounts below 20 mm contribute significantly to annual rainfall amounts in the dry part while all types of daily rainfall exceeding 1 mm have comparable contributions in the humid part. The climatologies indicated the highest likelihood of experiencing intense daily events during the core of the wet seasons with the highest frequencies in central Mozambique and the southern highlands of Tanzania. Interannual variations of rainfall indicated that significant changes had occurred between the late-1940s and early-1980s, particularly in the 1970s. The changes in rainfall were more evident in the number of daily rainfall events than in rainfall amounts, led generally to increasing early summer and decreased late summer rainfall. It was also found that intra-seasonal dry day sequences were an important parameter in the definition of a rainy season’s onset and end in southern Africa apart from rainfall amounts. Interannual variations of the rainy season characteristics (onset, end, duration) followed the variations of rainfall amounts and number of events. The duration of the rainy season was affected by the onset (Tanzania), onset or end (tropical southern Africa - southwestern highlands of Tanzania, Zambia, northern Zimbabwe and central Mozambique) and end (the remaing part of southern Africa). Flow duration curves (FDCs) identified three types of rivers (ephemeral, seasonal and perennial) in southern Africa with ephemeral rivers found mainly in the dry western part of the region. Seasonal streamflow patterns followed those of rainfall while interannual streamflow variations indicated significant changes of mean flows with little evidences of high and low flow regime changes except in Namibia and some parts of northern Zimbabwe. It was, however, not possible to provide strong links between the identified changes in streamflows and those in rainfall. Regarding the influences of climate variability on hydrological variability in southern Africa, rainfall variations in southern Africa were found to be influenced strongly by ENSO and SST in the tropical Indian ocean and moderately by SST in the south Madagascar basin. The influence of ENSO was consistent for all types of daily rainfall and peaks for the light and moderate (< 20 mm) events in the southern part and for the intense events in the northern part. SST in the tropical Indian ocean influence the light and moderate events while SST close to the region influence the heavy events. However, the relationships experienced significant changes in the mid-1950s and in the 1970s. The former changes led to improved associations while the latter deteriorated or reversed the relationships. The influences of climatic variables on streamflows and rainy season characteristics were inferred from the rainfall-streamflow and rainfall-climatic variables relationships.
- Full Text:
- Date Issued: 2005
- Authors: Valimba, Patrick
- Date: 2005
- Subjects: Rain and rainfall -- Africa, Southern Climatic changes -- Africa, Southern Streamflow -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6030 , http://hdl.handle.net/10962/d1006159
- Description: Hydrological variability involving rainfall and streamflows in southern Africa have been often studied separately or have used cumulative rainfall and streamflow indices. The main objective of this study was to investigate spatio-temporal variations of rainfall, their influences on streamflows and their relationships with climatic variations with emphasis on indices that characterise the hydrological extremes, floods and droughts. It was found that 60-70% of the time when it rains, daily rainfalls are below their long-term averages and daily amounts below 10 mm are the most frequent in southern Africa. Spatially, climatologies of rainfall sub-divided the southern African subcontinent into the dry western/southwestern part and the “humid” eastern and northern part. The daily amounts below 20 mm contribute significantly to annual rainfall amounts in the dry part while all types of daily rainfall exceeding 1 mm have comparable contributions in the humid part. The climatologies indicated the highest likelihood of experiencing intense daily events during the core of the wet seasons with the highest frequencies in central Mozambique and the southern highlands of Tanzania. Interannual variations of rainfall indicated that significant changes had occurred between the late-1940s and early-1980s, particularly in the 1970s. The changes in rainfall were more evident in the number of daily rainfall events than in rainfall amounts, led generally to increasing early summer and decreased late summer rainfall. It was also found that intra-seasonal dry day sequences were an important parameter in the definition of a rainy season’s onset and end in southern Africa apart from rainfall amounts. Interannual variations of the rainy season characteristics (onset, end, duration) followed the variations of rainfall amounts and number of events. The duration of the rainy season was affected by the onset (Tanzania), onset or end (tropical southern Africa - southwestern highlands of Tanzania, Zambia, northern Zimbabwe and central Mozambique) and end (the remaing part of southern Africa). Flow duration curves (FDCs) identified three types of rivers (ephemeral, seasonal and perennial) in southern Africa with ephemeral rivers found mainly in the dry western part of the region. Seasonal streamflow patterns followed those of rainfall while interannual streamflow variations indicated significant changes of mean flows with little evidences of high and low flow regime changes except in Namibia and some parts of northern Zimbabwe. It was, however, not possible to provide strong links between the identified changes in streamflows and those in rainfall. Regarding the influences of climate variability on hydrological variability in southern Africa, rainfall variations in southern Africa were found to be influenced strongly by ENSO and SST in the tropical Indian ocean and moderately by SST in the south Madagascar basin. The influence of ENSO was consistent for all types of daily rainfall and peaks for the light and moderate (< 20 mm) events in the southern part and for the intense events in the northern part. SST in the tropical Indian ocean influence the light and moderate events while SST close to the region influence the heavy events. However, the relationships experienced significant changes in the mid-1950s and in the 1970s. The former changes led to improved associations while the latter deteriorated or reversed the relationships. The influences of climatic variables on streamflows and rainy season characteristics were inferred from the rainfall-streamflow and rainfall-climatic variables relationships.
- Full Text:
- Date Issued: 2005
The role of anthropogenic disturbance in the creation of a socio-ecological landscape
- Authors: Fox, Helen Elizabeth
- Date: 2005
- Subjects: Human ecology -- South Africa -- Kat River Valley , Land use -- Environmental aspects-- South Africa -- Kat River Valley , Landscapes -- Social aspects -- South Africa -- Kat River Valley , Landscape ecology -- South Africa -- Kat River Valley , Vegetation and climate -- South Africa -- Kat River Valley , Xhosa (African people) -- Folklore , Kat River Valley (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4772 , http://hdl.handle.net/10962/d1008061 , Human ecology -- South Africa -- Kat River Valley , Land use -- Environmental aspects-- South Africa -- Kat River Valley , Landscapes -- Social aspects -- South Africa -- Kat River Valley , Landscape ecology -- South Africa -- Kat River Valley , Vegetation and climate -- South Africa -- Kat River Valley , Xhosa (African people) -- Folklore , Kat River Valley (South Africa)
- Description: The aim of this thesis is to examine the role of anthropogenic disturbance in the creation of a socio-ecological landscape. Three key questions were answered: what impact has past anthropogenic disturbance had on present vegetative characteristics; what value did this disturbed landscape have to local people; how did the local peoples' worldviews and eco-cosmologies influence how they perceived, valued and managed their landscape? Research was based in a rural, predominantly amaXhosa village in the Kat River valley, Eastern Cape, South Africa. Four major landscape components characterised the environment, namely dense forests, former grazing lands, abandoned fields and old settlements. A combination of qualitative and quantitative methods were adopted, consisting of a vegetation and soil survey and social science methods including semistructured interviews, focus groups, transect walks and participant observation. The key finding was that anthropogenic disturbance is necessary to enhance the potential of the area to support human habitation. However, anthropogenic disturbance can have positive or negative effects for both local people and the environment. An intermediate level of disturbance is a key factor leading to a resilient socio-ecological system. Various anthropogenic disturbances have had significant affects on vegetation characteristics in terms of species richness, and a change in vegetation composition and species heights. Of the three anthropogenic landscapes examined, former grazing lands were the least intensively disturbed. They were also more species rich and structurally diverse than areas that were under agricultural production or used as a settlement. Dense forests, although the least desirable landscape to local people were, together with sacred pools, sources of ecosystem renewal and played a critical role during times of disturbance. Anthropogenic disturbance has added value to local people's livelihoods; this disturbance has resulted in a patchy landscape that supplies a wide variety of resources to local people. Local people are dependent on their environment for their basic needs; this has encouraged sustainable management practices. The local AmaXhosa still retain many elements of their traditional worldview, which has many characteristics of Animism. The environment is an integral component of their belief system and certain sites and species have significant cultural value and are protected.
- Full Text:
- Date Issued: 2005
- Authors: Fox, Helen Elizabeth
- Date: 2005
- Subjects: Human ecology -- South Africa -- Kat River Valley , Land use -- Environmental aspects-- South Africa -- Kat River Valley , Landscapes -- Social aspects -- South Africa -- Kat River Valley , Landscape ecology -- South Africa -- Kat River Valley , Vegetation and climate -- South Africa -- Kat River Valley , Xhosa (African people) -- Folklore , Kat River Valley (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4772 , http://hdl.handle.net/10962/d1008061 , Human ecology -- South Africa -- Kat River Valley , Land use -- Environmental aspects-- South Africa -- Kat River Valley , Landscapes -- Social aspects -- South Africa -- Kat River Valley , Landscape ecology -- South Africa -- Kat River Valley , Vegetation and climate -- South Africa -- Kat River Valley , Xhosa (African people) -- Folklore , Kat River Valley (South Africa)
- Description: The aim of this thesis is to examine the role of anthropogenic disturbance in the creation of a socio-ecological landscape. Three key questions were answered: what impact has past anthropogenic disturbance had on present vegetative characteristics; what value did this disturbed landscape have to local people; how did the local peoples' worldviews and eco-cosmologies influence how they perceived, valued and managed their landscape? Research was based in a rural, predominantly amaXhosa village in the Kat River valley, Eastern Cape, South Africa. Four major landscape components characterised the environment, namely dense forests, former grazing lands, abandoned fields and old settlements. A combination of qualitative and quantitative methods were adopted, consisting of a vegetation and soil survey and social science methods including semistructured interviews, focus groups, transect walks and participant observation. The key finding was that anthropogenic disturbance is necessary to enhance the potential of the area to support human habitation. However, anthropogenic disturbance can have positive or negative effects for both local people and the environment. An intermediate level of disturbance is a key factor leading to a resilient socio-ecological system. Various anthropogenic disturbances have had significant affects on vegetation characteristics in terms of species richness, and a change in vegetation composition and species heights. Of the three anthropogenic landscapes examined, former grazing lands were the least intensively disturbed. They were also more species rich and structurally diverse than areas that were under agricultural production or used as a settlement. Dense forests, although the least desirable landscape to local people were, together with sacred pools, sources of ecosystem renewal and played a critical role during times of disturbance. Anthropogenic disturbance has added value to local people's livelihoods; this disturbance has resulted in a patchy landscape that supplies a wide variety of resources to local people. Local people are dependent on their environment for their basic needs; this has encouraged sustainable management practices. The local AmaXhosa still retain many elements of their traditional worldview, which has many characteristics of Animism. The environment is an integral component of their belief system and certain sites and species have significant cultural value and are protected.
- Full Text:
- Date Issued: 2005
Phylogeography and comparative ecophysiology of Chrysanthemoides Turn. Ex Medik. (Tribe Calenduleae)
- Authors: Howis, Seranne
- Date: 2005
- Subjects: Chrysanthemoides , Phylogeny , Ecophysiology , DNA , Plant genetics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4256 , http://hdl.handle.net/10962/d1008189
- Description: Chrysanthem Oides is a common Southern African shrub that grows in a variety of habitats. From coastal shrubland and fynbos to mountainous areas as far north as Kenya. The genus has two species and 8 subspecies. The diagnoses and delimitation of which have been based almost exclusively on morphological characteristics. This project aims to investigate, with the use of phylogenetic species concepts. The validity of these subspecies. Unlike biological species concepts that rely on reproductive isolation as a defining character of a species. Phylogenetic species concepts (PSC) are concerned with delimiting evolutionary significant units (ESUs). ESUs are evolutionarily isolated lineages, and under the PSC a species is an aggregation of organisms consistently diagnosable by a fixed character or combination of characters. This project therefore searched for genetic and physiological characters by which to delimit ESUs within the Cill), samhemoides genus. DNA sequencing was used to investigate the genetic characters, while gas exchange studies were used to investigate the ecophysiological characters. DNA sequence analysis indicated that the ESUs can be diagnosed by genetic means and that one species may be of hybrid origin. Field studies of three disparate genetically identifiable ESUs from three disparate climates found that there are noticeable differences in ecophysiological responses of these ESUs in the field. Plants from each ESU were transferred to a greenhouse and grown under identical conditions for several months and compared to determine if these traits are inherent, or elastic in relation to environmental conditions. Under simulated high rainfall conditions. There does not appear to be a significant difference in the photosynthetic traits.
- Full Text:
- Date Issued: 2005
Phylogeography and comparative ecophysiology of Chrysanthemoides Turn. Ex Medik. (Tribe Calenduleae)
- Authors: Howis, Seranne
- Date: 2005
- Subjects: Chrysanthemoides , Phylogeny , Ecophysiology , DNA , Plant genetics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4256 , http://hdl.handle.net/10962/d1008189
- Description: Chrysanthem Oides is a common Southern African shrub that grows in a variety of habitats. From coastal shrubland and fynbos to mountainous areas as far north as Kenya. The genus has two species and 8 subspecies. The diagnoses and delimitation of which have been based almost exclusively on morphological characteristics. This project aims to investigate, with the use of phylogenetic species concepts. The validity of these subspecies. Unlike biological species concepts that rely on reproductive isolation as a defining character of a species. Phylogenetic species concepts (PSC) are concerned with delimiting evolutionary significant units (ESUs). ESUs are evolutionarily isolated lineages, and under the PSC a species is an aggregation of organisms consistently diagnosable by a fixed character or combination of characters. This project therefore searched for genetic and physiological characters by which to delimit ESUs within the Cill), samhemoides genus. DNA sequencing was used to investigate the genetic characters, while gas exchange studies were used to investigate the ecophysiological characters. DNA sequence analysis indicated that the ESUs can be diagnosed by genetic means and that one species may be of hybrid origin. Field studies of three disparate genetically identifiable ESUs from three disparate climates found that there are noticeable differences in ecophysiological responses of these ESUs in the field. Plants from each ESU were transferred to a greenhouse and grown under identical conditions for several months and compared to determine if these traits are inherent, or elastic in relation to environmental conditions. Under simulated high rainfall conditions. There does not appear to be a significant difference in the photosynthetic traits.
- Full Text:
- Date Issued: 2005
Biology, population dynamics and management of carpenter (Argyrozona argyrozona) an endemic South African reef fish
- Authors: Brouwer, Stephen Leonard
- Date: 2005
- Subjects: Reef fishes -- South Africa Sparidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5241 , http://hdl.handle.net/10962/d1005084
- Description: Carpenter, Argyrozona argyrozona (Valenciennes, 1830), is an endemic South African sparid fish. They form an important component of the commercial linefishery on the South African east coast, where they are the third most important species landed. Recent investigations revealed that the catch per unit effort (cpue) of this species has declined markedly since the early 1900’s. Despite these declines and the importance of this resource, remarkably little biological information on this species exists for providing management advice. This thesis investigates the life history of carpenter, particularly those aspects that are used for management. This includes an investigation into the stock distribution and identification of nursery areas, and an assessment of age, growth, reproduction and movement patterns. Age and growth was assessed using methods based on both otoliths and mark-recapture. Transverse sagittal sections from the Tsitsikamma National Park showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. A. argyrozona were found to be long lived (up to 27 years) and slow growing. Within reader (between counts) and between readers average percent error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly under-estimated the age of fish older than 10 years (p<0.01). A large proportion (68%) of the individual growth rates derived from mark-recapture data were below those predicted by the otolith based von Bertalanffy growth model (p<0.01). This was attributed to the negative influence of external tags, as hydroids, frequently occurring on the tags of recaptured fish, were observed to cause severe lesions and in some cases, extensive fin damage. This brings into question the use of mark-recapture studies to calculate growth of some species. The effects of sampling design and sample size on age and growth estimation were assessed. The minimum sample size required to accurately estimate growth and mortality, and the effects of using either random or stratified sampling procedures were tested. Decimal and integer ageing both produced similar estimates of von Bertalanffy growth parameters, growth curves, spawner biomass-per-recruit (SB/R) and fishing mortality (F) estimates. Sampling monthly throughout the year and collecting data in a single large sample provided similar growth curves, von Bertalanffy, F and SB/R estimates. The data showed that estimates based on less than 300 random samples were unreliable. However, accurate growth parameter estimates were achievable with less than 200 samples if the sample was stratified with 10 or more samples per 2 cm size class. An investigation into the reproductive biology of A. argyrozona within the Tsitsikamma National Park revealed that they were serial spawning late gonochorists. The size at 50% maturity (L₅₀) was estimated at 292 and 297 mm FL for females and males, respectively. Both monthly gonadosomatic indices and macroscopically determined ovarian stages strongly suggest that A. argyrozona within the Tsitsikamma National Park spawn in the austral summer between November and April. The presence of post-ovulatory follicles (POF's) confirmed the six month spawning season, while monthly proportions of early (0-6 hour old) POF's showed that spawning frequency was highest (once every 1-2 days) from December to March. Although spawning season was more highly correlated to photoperiod (r = 0.859) than temperature (r = -0.161), the daily proportion of spawning fish was strongly correlated (r = 0.93) to ambient temperature over the range 9-22⁰C. Both spawning frequency and season increased with fish length. As a result of the allometric relationship between annual fecundity and fish mass a 3 kg fish was calculated to produce 5 fold more eggs per kilogram of body weight than a fish of 1 kg. In addition to producing more eggs per unit weight each year, larger fish also produce significantly larger eggs. Adult emigration and larval dispersal of A. argyrozona from the Tsitsikamma National Park (TNP), South Africa, were investigated using mark-recapture data and Acoustic Doppler Current Profiler measurements of currents. Tagging data showed that adult carpenter were mainly resident, with a small proportion (7%) leaving the TNP in both easterly and westerly directions. No relationship was found between fish movement patterns and fish size or time-at-liberty. Current patterns suggest that eggs and larvae spawned within the TNP are mainly transported eastwards towards established nursery grounds; the median estimated distance moved was 299 km (range 42-561 km) in 30 days (time to flexion). Given this pattern of ichthyoplankton dispersal together with the fact that adult carpenter within the TNP display a high degree of residency and that they are much more abundant than in adjacent fishing grounds (cpue = 23 times greater), it appears that the TNP protects a viable carpenter spawner population capable of seeding adjacent fishing grounds. Fishery independent biomass surveys and commercial linefish catch returns were used to elucidate the spatial patterns of A. argyrozona distributed along the South African continental shelf. Two distinct areas of abundance were determined, one on the central and the other on the eastern Agulhas Bank. Tagging studies revealed little exchange between them. Two distinct nursery areas were identified. These data suggest that in each area juvenile A. argyrozona settle and move inshore, and then move offshore as they grow. Otolith readability and growth rates varied between regions, with fish from the Eastern Cape having the lowest average percentage error and the slowest growth rates, readability decreased westward. L₅₀ varied between the central and eastern Agulhas Bank as did mass at length. Based on the distribution of carpenter, variability in otolith readability, mass at length, variation in growth and size at maturity, it is concluded that carpenter exist as two separate stocks, one on the central Agulhas Bank and the other on the eastern Agulhas Bank. SB/R, fecundity-per-recruit (Egg/R) and yield-per-recruit (Y/R) models were used to model both South African carpenter stocks. Owing to the allometric relationship between annual fecundity and individual size, Egg/R ratios were between 40 and 74% of SB/R at equivalent F. Egg/R ratios account for allometric increases in fecundity with size/age, and are therefore regarded as more accurate estimates of reproductive potential, and biological reference points for per-recruit analysis should wherever possible be based on this quantum. It is shown that the current length at first capture (lc) (250 mm TL) and F (at M = 0.1) will reduce Egg/R to 6.41% of the pristine value in the Eastern Cape and between 6.06 and 14.15% on the central Agulhas Bank, indicating that both stocks are heavily over exploited. An increase in lc from 250 to 350 mm TL and a 70% reduction in commercial fishing effort is recommended to attain a target reference point of 40% Egg/RF=0. Bag frequency analysis indicates that a reduction in daily bag limit from 10 to 4 fish.person¹.day⁻¹ would effect an equivalent reduction in recreational F. The trawl bycatch of carpenter is only 3% of the reported line catch, consequently restrictions to this fishery are not recommended.
- Full Text:
- Date Issued: 2005
- Authors: Brouwer, Stephen Leonard
- Date: 2005
- Subjects: Reef fishes -- South Africa Sparidae -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5241 , http://hdl.handle.net/10962/d1005084
- Description: Carpenter, Argyrozona argyrozona (Valenciennes, 1830), is an endemic South African sparid fish. They form an important component of the commercial linefishery on the South African east coast, where they are the third most important species landed. Recent investigations revealed that the catch per unit effort (cpue) of this species has declined markedly since the early 1900’s. Despite these declines and the importance of this resource, remarkably little biological information on this species exists for providing management advice. This thesis investigates the life history of carpenter, particularly those aspects that are used for management. This includes an investigation into the stock distribution and identification of nursery areas, and an assessment of age, growth, reproduction and movement patterns. Age and growth was assessed using methods based on both otoliths and mark-recapture. Transverse sagittal sections from the Tsitsikamma National Park showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. A. argyrozona were found to be long lived (up to 27 years) and slow growing. Within reader (between counts) and between readers average percent error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly under-estimated the age of fish older than 10 years (p<0.01). A large proportion (68%) of the individual growth rates derived from mark-recapture data were below those predicted by the otolith based von Bertalanffy growth model (p<0.01). This was attributed to the negative influence of external tags, as hydroids, frequently occurring on the tags of recaptured fish, were observed to cause severe lesions and in some cases, extensive fin damage. This brings into question the use of mark-recapture studies to calculate growth of some species. The effects of sampling design and sample size on age and growth estimation were assessed. The minimum sample size required to accurately estimate growth and mortality, and the effects of using either random or stratified sampling procedures were tested. Decimal and integer ageing both produced similar estimates of von Bertalanffy growth parameters, growth curves, spawner biomass-per-recruit (SB/R) and fishing mortality (F) estimates. Sampling monthly throughout the year and collecting data in a single large sample provided similar growth curves, von Bertalanffy, F and SB/R estimates. The data showed that estimates based on less than 300 random samples were unreliable. However, accurate growth parameter estimates were achievable with less than 200 samples if the sample was stratified with 10 or more samples per 2 cm size class. An investigation into the reproductive biology of A. argyrozona within the Tsitsikamma National Park revealed that they were serial spawning late gonochorists. The size at 50% maturity (L₅₀) was estimated at 292 and 297 mm FL for females and males, respectively. Both monthly gonadosomatic indices and macroscopically determined ovarian stages strongly suggest that A. argyrozona within the Tsitsikamma National Park spawn in the austral summer between November and April. The presence of post-ovulatory follicles (POF's) confirmed the six month spawning season, while monthly proportions of early (0-6 hour old) POF's showed that spawning frequency was highest (once every 1-2 days) from December to March. Although spawning season was more highly correlated to photoperiod (r = 0.859) than temperature (r = -0.161), the daily proportion of spawning fish was strongly correlated (r = 0.93) to ambient temperature over the range 9-22⁰C. Both spawning frequency and season increased with fish length. As a result of the allometric relationship between annual fecundity and fish mass a 3 kg fish was calculated to produce 5 fold more eggs per kilogram of body weight than a fish of 1 kg. In addition to producing more eggs per unit weight each year, larger fish also produce significantly larger eggs. Adult emigration and larval dispersal of A. argyrozona from the Tsitsikamma National Park (TNP), South Africa, were investigated using mark-recapture data and Acoustic Doppler Current Profiler measurements of currents. Tagging data showed that adult carpenter were mainly resident, with a small proportion (7%) leaving the TNP in both easterly and westerly directions. No relationship was found between fish movement patterns and fish size or time-at-liberty. Current patterns suggest that eggs and larvae spawned within the TNP are mainly transported eastwards towards established nursery grounds; the median estimated distance moved was 299 km (range 42-561 km) in 30 days (time to flexion). Given this pattern of ichthyoplankton dispersal together with the fact that adult carpenter within the TNP display a high degree of residency and that they are much more abundant than in adjacent fishing grounds (cpue = 23 times greater), it appears that the TNP protects a viable carpenter spawner population capable of seeding adjacent fishing grounds. Fishery independent biomass surveys and commercial linefish catch returns were used to elucidate the spatial patterns of A. argyrozona distributed along the South African continental shelf. Two distinct areas of abundance were determined, one on the central and the other on the eastern Agulhas Bank. Tagging studies revealed little exchange between them. Two distinct nursery areas were identified. These data suggest that in each area juvenile A. argyrozona settle and move inshore, and then move offshore as they grow. Otolith readability and growth rates varied between regions, with fish from the Eastern Cape having the lowest average percentage error and the slowest growth rates, readability decreased westward. L₅₀ varied between the central and eastern Agulhas Bank as did mass at length. Based on the distribution of carpenter, variability in otolith readability, mass at length, variation in growth and size at maturity, it is concluded that carpenter exist as two separate stocks, one on the central Agulhas Bank and the other on the eastern Agulhas Bank. SB/R, fecundity-per-recruit (Egg/R) and yield-per-recruit (Y/R) models were used to model both South African carpenter stocks. Owing to the allometric relationship between annual fecundity and individual size, Egg/R ratios were between 40 and 74% of SB/R at equivalent F. Egg/R ratios account for allometric increases in fecundity with size/age, and are therefore regarded as more accurate estimates of reproductive potential, and biological reference points for per-recruit analysis should wherever possible be based on this quantum. It is shown that the current length at first capture (lc) (250 mm TL) and F (at M = 0.1) will reduce Egg/R to 6.41% of the pristine value in the Eastern Cape and between 6.06 and 14.15% on the central Agulhas Bank, indicating that both stocks are heavily over exploited. An increase in lc from 250 to 350 mm TL and a 70% reduction in commercial fishing effort is recommended to attain a target reference point of 40% Egg/RF=0. Bag frequency analysis indicates that a reduction in daily bag limit from 10 to 4 fish.person¹.day⁻¹ would effect an equivalent reduction in recreational F. The trawl bycatch of carpenter is only 3% of the reported line catch, consequently restrictions to this fishery are not recommended.
- Full Text:
- Date Issued: 2005
Growth, feeding and sex change in the sequential protandric shrimp Nauticaris marionis Bate 1888 at the Prince Edward Islands (Southern Ocean)
- Authors: Vumazonke, Lukhanyiso Unam
- Date: 2005
- Subjects: Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5704 , http://hdl.handle.net/10962/d1005390 , Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Description: Demographic parameters and the general biology of the subantarctic shrimp Nauticaris marionis from the Prince Edward Islands were investigated. The carapace length is the most accurate indicator of body size and it was confirmed that N. marionis is a partially protandric hermaphrodite. Gravid females of N. marionis observed mainly in March with negligible hatching persisting until April/May. The majority of juveniles develop into males. Juveniles are characterised by an appendage on the endopodite of the first pleopod called the appendix interna or a.i.1. Juveniles that develop into males do so by growing a further appendage on the endopodite of the second pleopod. This appendage characterises males and is called the appendix masculina (or a.m.). Juveniles may develop directly into primary females through the development of an ovary and the loss of the a.i.1. The sequence differs among individuals, with some developing the ovary before losing the a.i.1 and others losing the a.i.1 first. Loss of the a.i.1 appears to be by shedding during a single moult, rather than by atrophy. Females can also develop by an alternative route as secondary females. Such animals first become males with an a.m. and then develop an ovary, thus forming an intermediate form called a tertium quid, or “third thing”. Again, there are two forms of tertium quid. Tertia quae a have the a.m. as well as the a.i.1. Tertia quae b have the a.m. in combination with an ovary but no a.i.1. Either form of tertium quid can develop into a secondary female through loss of the a.m., and in the case of the tertium quid a, loss of the a.i.1. It is unclear whether sexual differentiation occurs in the plankton or just after N. marionis settles on the benthos. The results of gut content analysis suggest that N. marionis is an opportunistic feeder, preying on a variety of prey with a preference for detritus, benthic amphipods and gastropods. Cannibalism of conspecific pleopods by large individuals of N. marionis occurred mostly in females, particularly in incubation containers. Cannibalism also occurs in males, and its occurrence depends on individual size, not gender. No diel patterns were observed in the feeding activity of N. marionis. In situ daily rations of males (carapace length <7mm) and females (>7mm) were equivalent to ≈10% and ≈5% of body dry weight, respectively. The von Bertalanffy growth curve parameters were empirically identified, by cohort analysis of data collected during 4 years, as K = 0.22239/year, L[subscript]∞ = 14.05789mm, t₀ = -0.05174, L₀ = 0.16083mm. N. marionis can survive up to seven years under natural conditions.
- Full Text:
- Date Issued: 2005
- Authors: Vumazonke, Lukhanyiso Unam
- Date: 2005
- Subjects: Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5704 , http://hdl.handle.net/10962/d1005390 , Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Description: Demographic parameters and the general biology of the subantarctic shrimp Nauticaris marionis from the Prince Edward Islands were investigated. The carapace length is the most accurate indicator of body size and it was confirmed that N. marionis is a partially protandric hermaphrodite. Gravid females of N. marionis observed mainly in March with negligible hatching persisting until April/May. The majority of juveniles develop into males. Juveniles are characterised by an appendage on the endopodite of the first pleopod called the appendix interna or a.i.1. Juveniles that develop into males do so by growing a further appendage on the endopodite of the second pleopod. This appendage characterises males and is called the appendix masculina (or a.m.). Juveniles may develop directly into primary females through the development of an ovary and the loss of the a.i.1. The sequence differs among individuals, with some developing the ovary before losing the a.i.1 and others losing the a.i.1 first. Loss of the a.i.1 appears to be by shedding during a single moult, rather than by atrophy. Females can also develop by an alternative route as secondary females. Such animals first become males with an a.m. and then develop an ovary, thus forming an intermediate form called a tertium quid, or “third thing”. Again, there are two forms of tertium quid. Tertia quae a have the a.m. as well as the a.i.1. Tertia quae b have the a.m. in combination with an ovary but no a.i.1. Either form of tertium quid can develop into a secondary female through loss of the a.m., and in the case of the tertium quid a, loss of the a.i.1. It is unclear whether sexual differentiation occurs in the plankton or just after N. marionis settles on the benthos. The results of gut content analysis suggest that N. marionis is an opportunistic feeder, preying on a variety of prey with a preference for detritus, benthic amphipods and gastropods. Cannibalism of conspecific pleopods by large individuals of N. marionis occurred mostly in females, particularly in incubation containers. Cannibalism also occurs in males, and its occurrence depends on individual size, not gender. No diel patterns were observed in the feeding activity of N. marionis. In situ daily rations of males (carapace length <7mm) and females (>7mm) were equivalent to ≈10% and ≈5% of body dry weight, respectively. The von Bertalanffy growth curve parameters were empirically identified, by cohort analysis of data collected during 4 years, as K = 0.22239/year, L[subscript]∞ = 14.05789mm, t₀ = -0.05174, L₀ = 0.16083mm. N. marionis can survive up to seven years under natural conditions.
- Full Text:
- Date Issued: 2005
Writing, identity, and change : a narrative case study of the use of journals to promote reflexivity within a Drama Studies curriculum
- Authors: Sutherland, Alexandra
- Date: 2005
- Subjects: Drama -- Study and teaching (Higher) -- South Africa Drama in education Scholarly publishing Academic writing Reflection (Philosophy) Playwriting
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1845 , http://hdl.handle.net/10962/d1004384
- Description: The study adopts a case study examination of three student reflective joumals written about class and field based applied Drama experiences over one year. The journals were written as part of a curriculum outcome to develop reflective practice, for one Drama Honours paper (Educational Drama and Theatre) at Rhodes University Drama Department, South Africa. Based on a narrative inquiry approach, the study documents the changes in identity, discourse, and representation of self and other, which emerge through the journal writing process. The research analyses how identities are constructed through reflective writing practices, and how these identities might relate to the arguments for the development of reflexivity. The development of reflexivity is seen as integral to contemporary educational policies associated with lifelong learning, and the skills required of graduates in South Africa's emerging democracy. These policies centre on means of preparing students for a world characterised by change and instability, or what Barnett (2000) has termed a "supercomplex world". The research findings suggest that journal writing within a Drama Studies curriculum, allows students to construct subjectivities which support Barnett's claim that "the main pedagogical task in a university is not that of the transmission of knowledge but of promoting forms of human being appropriate to the conditions of supercomplexity" (Barnett, 2000b: 164). In addition, the development of different writing genres within a Drama Studies curriculum allows students to develop disciplinarily relevant ways of discussing and researching artistic processes and products. A reflective journal is a potential site for students to interrogate and construct emerging identities which enable them to negotiate diversity, thus preparing them for their lives beyond the university.
- Full Text:
- Date Issued: 2005
- Authors: Sutherland, Alexandra
- Date: 2005
- Subjects: Drama -- Study and teaching (Higher) -- South Africa Drama in education Scholarly publishing Academic writing Reflection (Philosophy) Playwriting
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1845 , http://hdl.handle.net/10962/d1004384
- Description: The study adopts a case study examination of three student reflective joumals written about class and field based applied Drama experiences over one year. The journals were written as part of a curriculum outcome to develop reflective practice, for one Drama Honours paper (Educational Drama and Theatre) at Rhodes University Drama Department, South Africa. Based on a narrative inquiry approach, the study documents the changes in identity, discourse, and representation of self and other, which emerge through the journal writing process. The research analyses how identities are constructed through reflective writing practices, and how these identities might relate to the arguments for the development of reflexivity. The development of reflexivity is seen as integral to contemporary educational policies associated with lifelong learning, and the skills required of graduates in South Africa's emerging democracy. These policies centre on means of preparing students for a world characterised by change and instability, or what Barnett (2000) has termed a "supercomplex world". The research findings suggest that journal writing within a Drama Studies curriculum, allows students to construct subjectivities which support Barnett's claim that "the main pedagogical task in a university is not that of the transmission of knowledge but of promoting forms of human being appropriate to the conditions of supercomplexity" (Barnett, 2000b: 164). In addition, the development of different writing genres within a Drama Studies curriculum allows students to develop disciplinarily relevant ways of discussing and researching artistic processes and products. A reflective journal is a potential site for students to interrogate and construct emerging identities which enable them to negotiate diversity, thus preparing them for their lives beyond the university.
- Full Text:
- Date Issued: 2005
A case study investigation into the utility of baseline data versus normative data using a computer-based concussion management programme
- Authors: Mitchell, Julia
- Date: 2005
- Subjects: Brain -- Concussion , Neuropsychological tests , Sports injuries -- Psychological aspects , Head -- Wounds and injuries -- Complications
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3021 , http://hdl.handle.net/10962/d1002530 , Brain -- Concussion , Neuropsychological tests , Sports injuries -- Psychological aspects , Head -- Wounds and injuries -- Complications
- Description: Neuropsychological testing is recognised as one of the cornerstones of concussion evaluation, contributing significantly to both an understanding of the injury as well as management of the recovery process. Despite the high incidence of concussion at school level, traditional paper-and-pencil neuropsychological testing has generally been absent from school concussion management programmes, largely due to time and cost constraints. Now, the recent development of computerised neuropsychological testing is providing the opportunity for including neurocognitive assessment in this process. The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is a valid and reliable instrument of this type and normed on 13 - 18 year old North American high school athletes, as well as adult groups. The current recommendation is that athletes are baselined preseason in order to provide an individualised comparative level against which to monitor recovery and provide return-to-play recommendations. This in itself is quite a cumbersome process, thus the present study set out to ascertain whether baseline testing of all athletes is necessary, or whether the use of US or SA normative data alone would provide an appropriate standard against which to interpret the postinjury scores. From a leading South African rugby playing school, the 1st and 2nd rugby teams, (16 - 18 years) were baselined using ImPACT. Three athletes, who were subsequently referred with concussion during the rugby season, were followed up with serial testing on ImPACT. An analysis of the follow up scores was conducted to chart the athletes' recovery process, in relation to the athletes own baseline scores (using US and SA reliable change indices) and age appropriate US and SA normative ranges. The relative utility of individual baselines scores versus these normative ranges was then critically evaluated. It was concluded that a combination of both baseline and normative data provided optimal management of the athlete, with the methods complementing each other in the interpretation of post-injury results. Overall, the SA normative ranges seemed to provide slightly better management guidelines than the US normative ranges when used with this sample of South African high school athletes.
- Full Text:
- Date Issued: 2005
- Authors: Mitchell, Julia
- Date: 2005
- Subjects: Brain -- Concussion , Neuropsychological tests , Sports injuries -- Psychological aspects , Head -- Wounds and injuries -- Complications
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3021 , http://hdl.handle.net/10962/d1002530 , Brain -- Concussion , Neuropsychological tests , Sports injuries -- Psychological aspects , Head -- Wounds and injuries -- Complications
- Description: Neuropsychological testing is recognised as one of the cornerstones of concussion evaluation, contributing significantly to both an understanding of the injury as well as management of the recovery process. Despite the high incidence of concussion at school level, traditional paper-and-pencil neuropsychological testing has generally been absent from school concussion management programmes, largely due to time and cost constraints. Now, the recent development of computerised neuropsychological testing is providing the opportunity for including neurocognitive assessment in this process. The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is a valid and reliable instrument of this type and normed on 13 - 18 year old North American high school athletes, as well as adult groups. The current recommendation is that athletes are baselined preseason in order to provide an individualised comparative level against which to monitor recovery and provide return-to-play recommendations. This in itself is quite a cumbersome process, thus the present study set out to ascertain whether baseline testing of all athletes is necessary, or whether the use of US or SA normative data alone would provide an appropriate standard against which to interpret the postinjury scores. From a leading South African rugby playing school, the 1st and 2nd rugby teams, (16 - 18 years) were baselined using ImPACT. Three athletes, who were subsequently referred with concussion during the rugby season, were followed up with serial testing on ImPACT. An analysis of the follow up scores was conducted to chart the athletes' recovery process, in relation to the athletes own baseline scores (using US and SA reliable change indices) and age appropriate US and SA normative ranges. The relative utility of individual baselines scores versus these normative ranges was then critically evaluated. It was concluded that a combination of both baseline and normative data provided optimal management of the athlete, with the methods complementing each other in the interpretation of post-injury results. Overall, the SA normative ranges seemed to provide slightly better management guidelines than the US normative ranges when used with this sample of South African high school athletes.
- Full Text:
- Date Issued: 2005
Establishment and impact of the sap-sucking mirid, Falconia intermedia (Distant) (Hemiptera: Miridae) on Lantana camara (Verbenaceae) varieties in the Eastern Cape Province, South Africa
- Heshula, Unathi-Nkosi Lelethu Peter
- Authors: Heshula, Unathi-Nkosi Lelethu Peter
- Date: 2005
- Subjects: Lantana camara -- South Africa -- Eastern Cape , Biological pest control agents -- South Africa -- Eastern Cape , Hemiptera -- South Africa -- Eastern Cape , Miridae -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5832 , http://hdl.handle.net/10962/d1008085
- Description: The biological control of the weedy complex Lantana camara (L.) (Verbenaceae) has been ongoing in South Africa for over 40 years. Despite this, the weed is still not under sufficient control and continues to invade new territories in the country. The biological control programme needs to be bolstered with releases of new and potentially damaging biological control agents. A promising biological control agent endemic to Central America, Falconia intermedia (Distant) (Hemiptera: Miridae), was imported into quarantine from Jamaica in 1994. This agent was released on sites in KwaZulu-Natal and Limpopo provinces of South Africa in 1999. Even though it initially established and damaged L. camara, populations died out at most of the release sites. As varietal difference and adverse climate have been cited as the reason for non-establishment and ineffective control in L. camara biocontrol programmes worldwide, this study attempts to investigate the role that these two factors play in this weed herbivore relationship. Laboratory no-choice trials were conducted to determine the varietal performance of F intermedia, among five Eastern Cape varieties of the weed from East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm, and a variety from the Plant Protection Research Institute (PPRI), Pretoria. However, there were differences in performance as the adult mirids performed better on white-pink varieties from Whitney Farm and Heather Glen Farm. To test varietal preference in field conditions, field releases of F intermedia were also made at East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm. Post release evaluations were conducted monthly for two years (2002 and 2003). The insect established at East London and Whitney Farm, both of which have white-pink varieties. Insect populations quickly died out at the Lyndhurst Farm and Port Alfred sites, which have dark pink varieties. It is suggested that field conditions may have resulted in poor plant quality and led indirectly to varietal preference, and to non-establishment at these two sites. With the onset of cooler weather, populations disappeared at Heather Glen Farm. This suggested that F. intermedia was suitable for release in more subtropical areas within South Africa where climatic conditions would be suitable throughout the year. The mirid performed well at Whitney Farm, resulting in significant reduction in plant growth parameters such as height and percentage cover, and increasing the cover of other flora growing beneath L. camara plants. Finally, ways to improve the efficacy of this agent are considered in an effort towards better control of L. camara in South Africa.
- Full Text:
- Date Issued: 2005
- Authors: Heshula, Unathi-Nkosi Lelethu Peter
- Date: 2005
- Subjects: Lantana camara -- South Africa -- Eastern Cape , Biological pest control agents -- South Africa -- Eastern Cape , Hemiptera -- South Africa -- Eastern Cape , Miridae -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5832 , http://hdl.handle.net/10962/d1008085
- Description: The biological control of the weedy complex Lantana camara (L.) (Verbenaceae) has been ongoing in South Africa for over 40 years. Despite this, the weed is still not under sufficient control and continues to invade new territories in the country. The biological control programme needs to be bolstered with releases of new and potentially damaging biological control agents. A promising biological control agent endemic to Central America, Falconia intermedia (Distant) (Hemiptera: Miridae), was imported into quarantine from Jamaica in 1994. This agent was released on sites in KwaZulu-Natal and Limpopo provinces of South Africa in 1999. Even though it initially established and damaged L. camara, populations died out at most of the release sites. As varietal difference and adverse climate have been cited as the reason for non-establishment and ineffective control in L. camara biocontrol programmes worldwide, this study attempts to investigate the role that these two factors play in this weed herbivore relationship. Laboratory no-choice trials were conducted to determine the varietal performance of F intermedia, among five Eastern Cape varieties of the weed from East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm, and a variety from the Plant Protection Research Institute (PPRI), Pretoria. However, there were differences in performance as the adult mirids performed better on white-pink varieties from Whitney Farm and Heather Glen Farm. To test varietal preference in field conditions, field releases of F intermedia were also made at East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm. Post release evaluations were conducted monthly for two years (2002 and 2003). The insect established at East London and Whitney Farm, both of which have white-pink varieties. Insect populations quickly died out at the Lyndhurst Farm and Port Alfred sites, which have dark pink varieties. It is suggested that field conditions may have resulted in poor plant quality and led indirectly to varietal preference, and to non-establishment at these two sites. With the onset of cooler weather, populations disappeared at Heather Glen Farm. This suggested that F. intermedia was suitable for release in more subtropical areas within South Africa where climatic conditions would be suitable throughout the year. The mirid performed well at Whitney Farm, resulting in significant reduction in plant growth parameters such as height and percentage cover, and increasing the cover of other flora growing beneath L. camara plants. Finally, ways to improve the efficacy of this agent are considered in an effort towards better control of L. camara in South Africa.
- Full Text:
- Date Issued: 2005
A floristic study of a portion of the Pondoland Centre of Endeminism, Port St Johns, South Africa
- Authors: Cloete, Elizabeth Carinus
- Date: 2005
- Subjects: Endemic plants -- South Africa -- Port St Johns , Phytogeography -- South Africa -- Port St Johns , Plants -- South Africa -- Port St Johns , Alien plants -- South Africa -- Port St Johns
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4188 , http://hdl.handle.net/10962/d1003757 , Endemic plants -- South Africa -- Port St Johns , Phytogeography -- South Africa -- Port St Johns , Plants -- South Africa -- Port St Johns , Alien plants -- South Africa -- Port St Johns
- Description: Analysis of the flora of the Pondoland Centre of Endemism (PCE) recorded 2253 species in the combined checklist of four sites (Port St. Johns, Mkambati, Umtamvuna and Oribi Gorge). Of these 1 % species are endemic to Pondoland, representing 8.7% of the Species, 15% of the genera and 26% of the families of the combined flora. Forty-four percent ofthe combined flora was only recorded from one locality (between 17% and 26% of each flora) and only 12% of the flora was present in all four localities. Of the endemics only sixteen (8%) occurred in all four sites thus each site had its own complement of unique endemics and 21 % endemics were not recorded from any of the four sites. At species level the floras of Mkambati and Umtamvuna were the most similar, followed by that of Umtamvuna and Oribi Gorge. Port St Johns had the least in common with any of the othersites, but more in common with non-neighbours Umtamvuna and Oribi Gorge than with its nearest neighbour Mkambati. Mkambati and Umtamvuna had the largest proportion of PCE endemics and Port St Johns had the lowest. The four sites are quite similar at family level, sharing thirteen families in the top ten family list between them, but much less similar at generic level.
- Full Text:
- Date Issued: 2005
- Authors: Cloete, Elizabeth Carinus
- Date: 2005
- Subjects: Endemic plants -- South Africa -- Port St Johns , Phytogeography -- South Africa -- Port St Johns , Plants -- South Africa -- Port St Johns , Alien plants -- South Africa -- Port St Johns
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4188 , http://hdl.handle.net/10962/d1003757 , Endemic plants -- South Africa -- Port St Johns , Phytogeography -- South Africa -- Port St Johns , Plants -- South Africa -- Port St Johns , Alien plants -- South Africa -- Port St Johns
- Description: Analysis of the flora of the Pondoland Centre of Endemism (PCE) recorded 2253 species in the combined checklist of four sites (Port St. Johns, Mkambati, Umtamvuna and Oribi Gorge). Of these 1 % species are endemic to Pondoland, representing 8.7% of the Species, 15% of the genera and 26% of the families of the combined flora. Forty-four percent ofthe combined flora was only recorded from one locality (between 17% and 26% of each flora) and only 12% of the flora was present in all four localities. Of the endemics only sixteen (8%) occurred in all four sites thus each site had its own complement of unique endemics and 21 % endemics were not recorded from any of the four sites. At species level the floras of Mkambati and Umtamvuna were the most similar, followed by that of Umtamvuna and Oribi Gorge. Port St Johns had the least in common with any of the othersites, but more in common with non-neighbours Umtamvuna and Oribi Gorge than with its nearest neighbour Mkambati. Mkambati and Umtamvuna had the largest proportion of PCE endemics and Port St Johns had the lowest. The four sites are quite similar at family level, sharing thirteen families in the top ten family list between them, but much less similar at generic level.
- Full Text:
- Date Issued: 2005
Development and assessment of medicines information for antiretroviral therapy in Sub-Saharan Africa
- Authors: Mwingira, Betty
- Date: 2005
- Subjects: AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3779 , http://hdl.handle.net/10962/d1003257 , AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Full Text:
- Date Issued: 2005
Development and assessment of medicines information for antiretroviral therapy in Sub-Saharan Africa
- Authors: Mwingira, Betty
- Date: 2005
- Subjects: AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3779 , http://hdl.handle.net/10962/d1003257 , AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Full Text:
- Date Issued: 2005
Animal suffering in factory farming and the best way to prevent it
- Authors: Watkins, Gareth
- Date: 2005
- Subjects: Vegetarianism -- Moral and ethical aspects Food animals -- Moral and ethical aspects Animal rights Animal welfare Animal welfare -- Moral and ethical aspects Vegetarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2728 , http://hdl.handle.net/10962/d1003736
- Description: This thesis moves beyond the traditional approaches of how we ought to treat animals, and instead concentrates on the best strategy for preventing animal suffering in the farming industry. Chapter 1 considers the question of how we can know that animals feel pain, and concludes not only that it is rational to believe that they can, but also that this is a significant fact. Chapter 2 then analyses one possible strategy for helping to prevent animal suffering, namely demi-vegetarianism. For a number of reasons, however, this strategy is found to be flawed, therefore Chapter 3 analyses a second possible strategy, namely vegetarianism, and concludes that this is, in fact, the best strategy for helping to prevent animal suffering in the farming industry.
- Full Text:
- Date Issued: 2005
- Authors: Watkins, Gareth
- Date: 2005
- Subjects: Vegetarianism -- Moral and ethical aspects Food animals -- Moral and ethical aspects Animal rights Animal welfare Animal welfare -- Moral and ethical aspects Vegetarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2728 , http://hdl.handle.net/10962/d1003736
- Description: This thesis moves beyond the traditional approaches of how we ought to treat animals, and instead concentrates on the best strategy for preventing animal suffering in the farming industry. Chapter 1 considers the question of how we can know that animals feel pain, and concludes not only that it is rational to believe that they can, but also that this is a significant fact. Chapter 2 then analyses one possible strategy for helping to prevent animal suffering, namely demi-vegetarianism. For a number of reasons, however, this strategy is found to be flawed, therefore Chapter 3 analyses a second possible strategy, namely vegetarianism, and concludes that this is, in fact, the best strategy for helping to prevent animal suffering in the farming industry.
- Full Text:
- Date Issued: 2005
September 11 : catalyst for structural-genealogical narrative of a new world (Dis)order
- Authors: Buijs, Lorena Maria Elisa
- Date: 2005
- Subjects: September 11 Terrorist Attacks, 2001 , United States -- Politics and government -- 2001- , Terrorism -- Government policy -- United States , United States -- Foreign relations -- Middle East , Middle East -- Foreign relations -- United States , Islam and world politics , Terrorism -- Religious aspects -- Islam , Jihad
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2852 , http://hdl.handle.net/10962/d1006463 , September 11 Terrorist Attacks, 2001 , United States -- Politics and government -- 2001- , Terrorism -- Government policy -- United States , United States -- Foreign relations -- Middle East , Middle East -- Foreign relations -- United States , Islam and world politics , Terrorism -- Religious aspects -- Islam , Jihad
- Description: The attacks of September 11, 2001, have changed America forever. In a horrific manner the vulnerability of the highly developed states was demonstrated and exposed in world politics. The event is ushering a new political era where far reaching shifts in international relations are under way. In the post Cold-War international world it appears that the ideological conflict between capitalism and socialism has been replaced by a new world order. One that has retained the binary conflict structure of the Cold War, except that this binary is now presented by political Islam and consumerist's capitalism (Martin, 2000:155). Indeed, in the previous bipolar world order, the acute distinction between capitalism and communism served to attenuate the discord in and between religions. This complex blurring of distinctions has been systematically heightened since the end of the Cold War, as it has allowed Western governments to maintain controlling interests outside of their dominions (Gupta, 2002:6) . This struggle has since been conceived in a variety of different, but related ways: A 'Clash of Civilizations' (Huntington 1996), or as an inescapable dialectic typical of the process of globalization itself (Barber, 1996:245). In the case of Huntington's (1996:19-20) genealogical narrative, he refers to global politics and the way in which the future will be reconfigured according to cultural identities. The division along these cultural lines, will furthermore "shape" the patterns of cohesion, disintegration, and conflict in the Post-Cold War world" (Huntington, 1996:20). Huntington's thesis is rather overriding in explaining the clash between the supposedly 'West' vs. 'Rest', whose interaction is historically determined. Yet, the genealogical narrative is not sufficient in taking into account the dynamics of globalization. Benjamin Barber's structural narrative, on the other hand, goes to great lengths to illustrate the paradoxical relationship between Jihad and McWorld, and how both forces tend to survive in a world that they inevitably create. By' acknowledging the relevance of both binaries (East/West), it is hoped to transcend them by presenting a structural-genealogical grand narrative, which will essentially allow one to understand Jihad as being a structural moment of the genealogical narrative. Given this general strategy, it will become perceptible that Jihad is one form of anti-globalization as the structural narratives become part of the genealogical and the genealogical part of the structural. In essence, then, this thesis is attempting to come to grips with the phenomenon of September 11, from a political-philosophical perspective. More specifically, this study will firstly be looking at two different, but related narratives that have emerged post-September 11, to make sense of the event. Given the structural-genealogical approach, the central concern in this study is consequently to look at two separate but related interests. The one pertains to history and the other to historiography.
- Full Text:
- Date Issued: 2005
- Authors: Buijs, Lorena Maria Elisa
- Date: 2005
- Subjects: September 11 Terrorist Attacks, 2001 , United States -- Politics and government -- 2001- , Terrorism -- Government policy -- United States , United States -- Foreign relations -- Middle East , Middle East -- Foreign relations -- United States , Islam and world politics , Terrorism -- Religious aspects -- Islam , Jihad
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2852 , http://hdl.handle.net/10962/d1006463 , September 11 Terrorist Attacks, 2001 , United States -- Politics and government -- 2001- , Terrorism -- Government policy -- United States , United States -- Foreign relations -- Middle East , Middle East -- Foreign relations -- United States , Islam and world politics , Terrorism -- Religious aspects -- Islam , Jihad
- Description: The attacks of September 11, 2001, have changed America forever. In a horrific manner the vulnerability of the highly developed states was demonstrated and exposed in world politics. The event is ushering a new political era where far reaching shifts in international relations are under way. In the post Cold-War international world it appears that the ideological conflict between capitalism and socialism has been replaced by a new world order. One that has retained the binary conflict structure of the Cold War, except that this binary is now presented by political Islam and consumerist's capitalism (Martin, 2000:155). Indeed, in the previous bipolar world order, the acute distinction between capitalism and communism served to attenuate the discord in and between religions. This complex blurring of distinctions has been systematically heightened since the end of the Cold War, as it has allowed Western governments to maintain controlling interests outside of their dominions (Gupta, 2002:6) . This struggle has since been conceived in a variety of different, but related ways: A 'Clash of Civilizations' (Huntington 1996), or as an inescapable dialectic typical of the process of globalization itself (Barber, 1996:245). In the case of Huntington's (1996:19-20) genealogical narrative, he refers to global politics and the way in which the future will be reconfigured according to cultural identities. The division along these cultural lines, will furthermore "shape" the patterns of cohesion, disintegration, and conflict in the Post-Cold War world" (Huntington, 1996:20). Huntington's thesis is rather overriding in explaining the clash between the supposedly 'West' vs. 'Rest', whose interaction is historically determined. Yet, the genealogical narrative is not sufficient in taking into account the dynamics of globalization. Benjamin Barber's structural narrative, on the other hand, goes to great lengths to illustrate the paradoxical relationship between Jihad and McWorld, and how both forces tend to survive in a world that they inevitably create. By' acknowledging the relevance of both binaries (East/West), it is hoped to transcend them by presenting a structural-genealogical grand narrative, which will essentially allow one to understand Jihad as being a structural moment of the genealogical narrative. Given this general strategy, it will become perceptible that Jihad is one form of anti-globalization as the structural narratives become part of the genealogical and the genealogical part of the structural. In essence, then, this thesis is attempting to come to grips with the phenomenon of September 11, from a political-philosophical perspective. More specifically, this study will firstly be looking at two different, but related narratives that have emerged post-September 11, to make sense of the event. Given the structural-genealogical approach, the central concern in this study is consequently to look at two separate but related interests. The one pertains to history and the other to historiography.
- Full Text:
- Date Issued: 2005
A critical investigation of plant optimization, to improve the production process of Mercedes-Benz commercial vehicles in South Africa. (Jan 2004 - Sept 2004)
- Authors: Naidoo, Desalin Rajoo
- Date: 2005
- Subjects: Automobile industry and trade -- South Africa -- Management Motor vehicle industry -- Production control -- South Africa Production management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:737 , http://hdl.handle.net/10962/d1003857
- Description: The research thesis reflects a positive improvement to the plant efficiency through strategic optimisation planning and controlling systems. It’s important to note that the set goals of the research were achieved, with total employee buy-in contributing to the success and sustainability of these improvements. Purposive sample methods allowed for the twenty employees from a total of 172, to be interviewed for both the pre and post testing. The paradigm of the research contributed to integrative communication between brainstorming and action. The efforts of the total workforce must be commended, for strategically aligning the organizational goals and objectives to realization. The content of the thesis, show a direct relationship between the plant optimisation and the increase in the production volumes. The understanding of the downtime reports for the period specified is a direct reflection to the improvement in quality, and the reduction of the overall poor workmanship graphs indicates positively to the reduction in cost. The last value driver, on-time delivery shows a vast improvement in maintaining the customer satisfaction, when considering the increase to the production volume capacity. These improvements have made further volume increases probable, and the understanding of Ikhwezi Trucktech management to negotiate with realized information for future capacity planning.
- Full Text:
- Date Issued: 2005
- Authors: Naidoo, Desalin Rajoo
- Date: 2005
- Subjects: Automobile industry and trade -- South Africa -- Management Motor vehicle industry -- Production control -- South Africa Production management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:737 , http://hdl.handle.net/10962/d1003857
- Description: The research thesis reflects a positive improvement to the plant efficiency through strategic optimisation planning and controlling systems. It’s important to note that the set goals of the research were achieved, with total employee buy-in contributing to the success and sustainability of these improvements. Purposive sample methods allowed for the twenty employees from a total of 172, to be interviewed for both the pre and post testing. The paradigm of the research contributed to integrative communication between brainstorming and action. The efforts of the total workforce must be commended, for strategically aligning the organizational goals and objectives to realization. The content of the thesis, show a direct relationship between the plant optimisation and the increase in the production volumes. The understanding of the downtime reports for the period specified is a direct reflection to the improvement in quality, and the reduction of the overall poor workmanship graphs indicates positively to the reduction in cost. The last value driver, on-time delivery shows a vast improvement in maintaining the customer satisfaction, when considering the increase to the production volume capacity. These improvements have made further volume increases probable, and the understanding of Ikhwezi Trucktech management to negotiate with realized information for future capacity planning.
- Full Text:
- Date Issued: 2005