An evaluation of policies for attaining excellence in service delivery in the Port Elizabeth municipality
- Binza, Mzikayise Shakespeare
- Authors: Binza, Mzikayise Shakespeare
- Date: 2000
- Subjects: Customer services -- Quality control , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10777 , http://hdl.handle.net/10948/d1006186 , Customer services -- Quality control , Customer services -- Management
- Description: This dissertation is based on the assumption that the Port Elizabeth Municipality should deliver essential services effectively, efficiently and economically so as to attain excellence in service delivery. The essential services dealt with in this study are electricity; refuse collection; sewerage; and water services. Attaining excellence in service delivery will lead the Port Elizabeth Municipality to improve and sustain the quality of life of the local inhabitants. The primary objectives of this dissertation include, inter alia: An historical analysis of delivery systems of the former government prior to 1994, which provides the primary reasons and purposes of delivery systems, and the effects on the Port Elizabeth Municipality. Reformation and transformation of South African local government since 1994, with particular reference to the Port Elizabeth Municipality. A normative model for service delivery, which is designed to accelerate service delivery in the local spheres of government, with special reference to the Port Elizabeth Municipality as the locus of this study. The nature, extent and evaluation of the existing service delivery by the Port Elizabeth Municipality from 1994 to 1999. An empirical survey is conducted in the form of questionnaires to the directors, heads of departments, senior managers, as well as councillors. Approaches and strategies for attaining excellence in service delivery, which include, inter alia: a government-business paradigm and an equilibrium approach. Lastly, a number of recommendations are made and conclusions are drawn based on the findings of the empirical survey in order to deliver essential services equitably, efficiently, effectively and economically to attain excellence in service delivery in the Port Elizabeth Municipality.
- Full Text:
- Date Issued: 2000
- Authors: Binza, Mzikayise Shakespeare
- Date: 2000
- Subjects: Customer services -- Quality control , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10777 , http://hdl.handle.net/10948/d1006186 , Customer services -- Quality control , Customer services -- Management
- Description: This dissertation is based on the assumption that the Port Elizabeth Municipality should deliver essential services effectively, efficiently and economically so as to attain excellence in service delivery. The essential services dealt with in this study are electricity; refuse collection; sewerage; and water services. Attaining excellence in service delivery will lead the Port Elizabeth Municipality to improve and sustain the quality of life of the local inhabitants. The primary objectives of this dissertation include, inter alia: An historical analysis of delivery systems of the former government prior to 1994, which provides the primary reasons and purposes of delivery systems, and the effects on the Port Elizabeth Municipality. Reformation and transformation of South African local government since 1994, with particular reference to the Port Elizabeth Municipality. A normative model for service delivery, which is designed to accelerate service delivery in the local spheres of government, with special reference to the Port Elizabeth Municipality as the locus of this study. The nature, extent and evaluation of the existing service delivery by the Port Elizabeth Municipality from 1994 to 1999. An empirical survey is conducted in the form of questionnaires to the directors, heads of departments, senior managers, as well as councillors. Approaches and strategies for attaining excellence in service delivery, which include, inter alia: a government-business paradigm and an equilibrium approach. Lastly, a number of recommendations are made and conclusions are drawn based on the findings of the empirical survey in order to deliver essential services equitably, efficiently, effectively and economically to attain excellence in service delivery in the Port Elizabeth Municipality.
- Full Text:
- Date Issued: 2000
Principals' perceptions of the management of staff appraisal in schools.
- Authors: Blaauw, Lindiwe Ellen
- Date: 2000
- Subjects: Educational evaluation , Teachers -- Rating of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2011 , http://hdl.handle.net/10962/d1016080
- Description: Teacher appraisal has long been a contentious and contested area in educational management. The recent implementation of a new system of appraisal in Eastern Cape Schools has led to renewed interest in the role and management of appraisal. The objective of this study was to investigate principals' perception of the management of staff appraisal. An interpretive paradigm was adopted and the research is a case study of four secondary schools in Port Elizabeth. Two methods were used in collecting data, namely, questionnaires and interviews. The content comparative method was used to analyse the data. The findings of this study showed areas of continuities and discontinuities with the literature and the new document on appraisal. There is a clear understanding among the principals interviewed that staff appraisal should be used to assess individual teacher performance and that it should also be developmental. There is clear support from the principals on the involvement of other stakeholders. They see the process as transformative and participatory. They find it acceptable and are willing to be involved. However, the findings also indicate a lack of readiness on the part of the principals to fully embrace a fully participative and developmental approach to appraisal. On the strength of these findings I conclude the thesis by making recommendations for policy, principals, teachers and for future researchers in the field.
- Full Text:
- Date Issued: 2000
- Authors: Blaauw, Lindiwe Ellen
- Date: 2000
- Subjects: Educational evaluation , Teachers -- Rating of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2011 , http://hdl.handle.net/10962/d1016080
- Description: Teacher appraisal has long been a contentious and contested area in educational management. The recent implementation of a new system of appraisal in Eastern Cape Schools has led to renewed interest in the role and management of appraisal. The objective of this study was to investigate principals' perception of the management of staff appraisal. An interpretive paradigm was adopted and the research is a case study of four secondary schools in Port Elizabeth. Two methods were used in collecting data, namely, questionnaires and interviews. The content comparative method was used to analyse the data. The findings of this study showed areas of continuities and discontinuities with the literature and the new document on appraisal. There is a clear understanding among the principals interviewed that staff appraisal should be used to assess individual teacher performance and that it should also be developmental. There is clear support from the principals on the involvement of other stakeholders. They see the process as transformative and participatory. They find it acceptable and are willing to be involved. However, the findings also indicate a lack of readiness on the part of the principals to fully embrace a fully participative and developmental approach to appraisal. On the strength of these findings I conclude the thesis by making recommendations for policy, principals, teachers and for future researchers in the field.
- Full Text:
- Date Issued: 2000
The interpretation of ABET placement tests in the recognition of prior learning
- Authors: Blunt, Sandra Viki
- Date: 2000
- Subjects: English language -- Ability testing , English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1582 , http://hdl.handle.net/10962/d1003464
- Description: This thesis analyses the way in which placement testing is being interpreted in Adult Basic Education and Training (ABET). The thesis examines whether the placement tests used in the case study were valid in terms of whether their contents were relevant and authentic with regard to what English second language speakers could reasonably be expected to know. Adult learners have differing English second language knowledge depending on the different contexts in which they have learned their second language. This thesis investigates the implications of the different contexts and different language needs of adult learners for the testing of English as a second language for placement purposes in ABET programmes. The thesis examined two placement tests to determine how the recognition of prior second language learning was being interpreted and how the interpretation affected the validity of the tests. Learners= perceptions of the assessment process and test content were elicited in order to determine whether a policy of transparency had been followed in the implementation of the assessment. It was also established what the goals of the organisation were in implementing an ABET programme. This research suggests that placement testing should be viewed holistically; in other words, the goals of the organisation and the level of transparency affect the validity of the placement test. The conclusions were that the placement tests were inauthentic since their contents excluded certain vital aspects of real life performance, namely, that related to the work context. The research revealed that if the placement testing process and the ABET programme are integrated into the culture of the organisation and if employees are remunerated when they have passed the different levels in the programme, the programme is likely to achieve a fair measure of success. Recommendations are that literacy should be viewed as based on a variety of contexts and uses and that therefore tests should be tailored to suit each particular organisation and should contain workrelated content. Furthermore, multiple methods of assessment should be considered.
- Full Text:
- Date Issued: 2000
- Authors: Blunt, Sandra Viki
- Date: 2000
- Subjects: English language -- Ability testing , English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1582 , http://hdl.handle.net/10962/d1003464
- Description: This thesis analyses the way in which placement testing is being interpreted in Adult Basic Education and Training (ABET). The thesis examines whether the placement tests used in the case study were valid in terms of whether their contents were relevant and authentic with regard to what English second language speakers could reasonably be expected to know. Adult learners have differing English second language knowledge depending on the different contexts in which they have learned their second language. This thesis investigates the implications of the different contexts and different language needs of adult learners for the testing of English as a second language for placement purposes in ABET programmes. The thesis examined two placement tests to determine how the recognition of prior second language learning was being interpreted and how the interpretation affected the validity of the tests. Learners= perceptions of the assessment process and test content were elicited in order to determine whether a policy of transparency had been followed in the implementation of the assessment. It was also established what the goals of the organisation were in implementing an ABET programme. This research suggests that placement testing should be viewed holistically; in other words, the goals of the organisation and the level of transparency affect the validity of the placement test. The conclusions were that the placement tests were inauthentic since their contents excluded certain vital aspects of real life performance, namely, that related to the work context. The research revealed that if the placement testing process and the ABET programme are integrated into the culture of the organisation and if employees are remunerated when they have passed the different levels in the programme, the programme is likely to achieve a fair measure of success. Recommendations are that literacy should be viewed as based on a variety of contexts and uses and that therefore tests should be tailored to suit each particular organisation and should contain workrelated content. Furthermore, multiple methods of assessment should be considered.
- Full Text:
- Date Issued: 2000
Cumulative mild head injury in contact sport: a comparison of the cognitive profiles of rugby players and non-contact sport controls with normative data
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Date Issued: 2000
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Date Issued: 2000
The implications of the introduction of outcomes based education in the natural sciences curriculum at Cape College of Education: the assessment of perceptions of squatter camp teachers in Khayelitsha towards the outcomes based education
- Authors: Booi, Kwanele
- Date: 2000
- Subjects: Competency-based education -- South Africa Competency-based education -- Evaluation Competency-based education -- South Africa -- Khayelitsha -- Evaluation Physical sciences -- Study and teaching -- Evaluation Life sciences -- Study and teaching -- Evaluation Cape College of Education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1569 , http://hdl.handle.net/10962/d1003451
- Description: 1. This pilot study is a survey of practices of natural sciences educators at Cape College of Education to establish if they reflect the conceptual development, development of skills, change of attitudes and values that are the pillars of the Outcomes Based Education (OBE). Their approaches of lecturing have been assessed to determine if they incorporate investigative approaches based on social constructivism, the theory underpinning Curriculum 2005. The status of science education in the college has been analyzed to establish whether the curriculum can adapt itself to the specifications of the new curriculum. It has been concluded that the educators at Cape College of Education need to be empowered about strategies that will help them function along the principles embracing Curriculum 2005 specifications. The educators have shown not to be ready to practice social constructivism and the assessment strategies incorporated in their programmes do not embrace a variety of approaches that will enable their learners to develop conceptually, skill wise and enable them to develop change in attitudes and values. Investigative approaches to practical work appear to be lacking in the college teaching/learning and this also indicates that Curriculum 2005 will take time to be properly implemented at Cape College of Education. 2. This study is based on the practices of science educators in the squatter-camp school in Khayelitsha, a densely populated area for blacks near Cape Town. Teachers at Vuselela primary school were interviewed about their teaching assessment strategies to establish whether they incorporate a learner centred approach, which is the necessity for the Outcomes Based Education approach. Also some of the lessons they taught were observed in order to find out whether they validate what transpired from the interviews through a process of triangulation. It has become evident that the teachers are to some extent aware of the changes the education system is going through in South Africa. It also became clear from the study that the teachers are still lacking expertise as to how to practice along the lines of Curriculum 2005, the South African version of Outcomes Based Education (OBE). They also showed that they are keen to learn and practice OBE even though more opportunities need to be created for their epistemological empowerment as well as empowerment on the content of science.
- Full Text:
- Date Issued: 2000
- Authors: Booi, Kwanele
- Date: 2000
- Subjects: Competency-based education -- South Africa Competency-based education -- Evaluation Competency-based education -- South Africa -- Khayelitsha -- Evaluation Physical sciences -- Study and teaching -- Evaluation Life sciences -- Study and teaching -- Evaluation Cape College of Education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1569 , http://hdl.handle.net/10962/d1003451
- Description: 1. This pilot study is a survey of practices of natural sciences educators at Cape College of Education to establish if they reflect the conceptual development, development of skills, change of attitudes and values that are the pillars of the Outcomes Based Education (OBE). Their approaches of lecturing have been assessed to determine if they incorporate investigative approaches based on social constructivism, the theory underpinning Curriculum 2005. The status of science education in the college has been analyzed to establish whether the curriculum can adapt itself to the specifications of the new curriculum. It has been concluded that the educators at Cape College of Education need to be empowered about strategies that will help them function along the principles embracing Curriculum 2005 specifications. The educators have shown not to be ready to practice social constructivism and the assessment strategies incorporated in their programmes do not embrace a variety of approaches that will enable their learners to develop conceptually, skill wise and enable them to develop change in attitudes and values. Investigative approaches to practical work appear to be lacking in the college teaching/learning and this also indicates that Curriculum 2005 will take time to be properly implemented at Cape College of Education. 2. This study is based on the practices of science educators in the squatter-camp school in Khayelitsha, a densely populated area for blacks near Cape Town. Teachers at Vuselela primary school were interviewed about their teaching assessment strategies to establish whether they incorporate a learner centred approach, which is the necessity for the Outcomes Based Education approach. Also some of the lessons they taught were observed in order to find out whether they validate what transpired from the interviews through a process of triangulation. It has become evident that the teachers are to some extent aware of the changes the education system is going through in South Africa. It also became clear from the study that the teachers are still lacking expertise as to how to practice along the lines of Curriculum 2005, the South African version of Outcomes Based Education (OBE). They also showed that they are keen to learn and practice OBE even though more opportunities need to be created for their epistemological empowerment as well as empowerment on the content of science.
- Full Text:
- Date Issued: 2000
Key decision-makers' perceptions of sustainable sea fisheries in Namibia and the implications for environmental education programmes
- Authors: Boois, Ulrich
- Date: 2000
- Subjects: Environmental education -- Namibia Fisheries -- Environmental aspects Fisheries -- Environmental aspects -- Namibia Sustainable development -- Environmental aspects Sustainable development -- Environmental aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1661 , http://hdl.handle.net/10962/d1003544
- Description: This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.
- Full Text:
- Date Issued: 2000
- Authors: Boois, Ulrich
- Date: 2000
- Subjects: Environmental education -- Namibia Fisheries -- Environmental aspects Fisheries -- Environmental aspects -- Namibia Sustainable development -- Environmental aspects Sustainable development -- Environmental aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1661 , http://hdl.handle.net/10962/d1003544
- Description: This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.
- Full Text:
- Date Issued: 2000
Histological validation of gonadal macroscopic staging criteria for Labeo cylindricus (Pisces: Cyprinidae)
- Booth, Anthony J, Weyl, Olaf L F
- Authors: Booth, Anthony J , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124593 , vital:35634 , https://doi.org/10.1080/15627020.2000.11657094
- Description: Histological examination of gametogenesis revealed that the current staging criteria used to assess gonadal recrudescence of the redeye labeo, Labeo cylindricus, were adequate. Gametogenesis was qualitatively similar to that of freshwater teleosts with a clearly defined seasonal reproductive cycle. L. cylindricus undergoes seasonal gross morphological and cytological gonadal changes with previtellogenesis dominating during the winter, vitellogenic development during spring and summer culminating in large-scale spawning at the end of summer. Post-spawning mass atresia of oocytes was evident in autumn. The histological data presented support macroscopical evidence that L. cylindricus is a synchronous iteroparous spawner, reproducing over a short period each year throughout its life-span.
- Full Text:
- Date Issued: 2010
- Authors: Booth, Anthony J , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124593 , vital:35634 , https://doi.org/10.1080/15627020.2000.11657094
- Description: Histological examination of gametogenesis revealed that the current staging criteria used to assess gonadal recrudescence of the redeye labeo, Labeo cylindricus, were adequate. Gametogenesis was qualitatively similar to that of freshwater teleosts with a clearly defined seasonal reproductive cycle. L. cylindricus undergoes seasonal gross morphological and cytological gonadal changes with previtellogenesis dominating during the winter, vitellogenic development during spring and summer culminating in large-scale spawning at the end of summer. Post-spawning mass atresia of oocytes was evident in autumn. The histological data presented support macroscopical evidence that L. cylindricus is a synchronous iteroparous spawner, reproducing over a short period each year throughout its life-span.
- Full Text:
- Date Issued: 2010
Incorporating the spatial component of fisheries data into stock assessment models
- Authors: Booth, Anthony J
- Date: 2000
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124800 , vital:35698 , https://doi.10.1006/jmsc.2000.0816
- Description: Fisheries-dependent and independent data have a strong spatial component. These data are also multi-dimensional, making them difficult to visualize and analyze, prompting the use of spatial analysis to facilitate an understanding of their relationships. One aspect of fisheries data that is often ignored is the distribution and abundance of a particular resource and the fishing patterns of its harvesting fisheries. In order to improve management advice, stock assessors need to incorporate the spatial component of these data into an existing assessment framework. This paper presents a three-dimensional visualization of the age-structure and fishery dependent and independent data associated with the sparid fish Pterogymnus laniarius on the Agulhas Bank, South Africa. A spatially-referenced spawner biomass per-recruit model is developed to illustrate the applicability of incorporating spatially referenced information in providing management advice. The model provided evidence that, even on a spatial scale, fishing mortality is significantly correlated to fishing effort. Areas of high levels of spawner biomass are noted, all of which corresponded to those geographic areas with a combination of low fishing effort and high adult biomass.
- Full Text:
- Date Issued: 2000
- Authors: Booth, Anthony J
- Date: 2000
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124800 , vital:35698 , https://doi.10.1006/jmsc.2000.0816
- Description: Fisheries-dependent and independent data have a strong spatial component. These data are also multi-dimensional, making them difficult to visualize and analyze, prompting the use of spatial analysis to facilitate an understanding of their relationships. One aspect of fisheries data that is often ignored is the distribution and abundance of a particular resource and the fishing patterns of its harvesting fisheries. In order to improve management advice, stock assessors need to incorporate the spatial component of these data into an existing assessment framework. This paper presents a three-dimensional visualization of the age-structure and fishery dependent and independent data associated with the sparid fish Pterogymnus laniarius on the Agulhas Bank, South Africa. A spatially-referenced spawner biomass per-recruit model is developed to illustrate the applicability of incorporating spatially referenced information in providing management advice. The model provided evidence that, even on a spatial scale, fishing mortality is significantly correlated to fishing effort. Areas of high levels of spawner biomass are noted, all of which corresponded to those geographic areas with a combination of low fishing effort and high adult biomass.
- Full Text:
- Date Issued: 2000
Spatial aspects of the reproductive and feeding biology of the striped robber, Brycinus lateralis (Pisces: Characidae), in the Okavango Delta, Botswana
- Booth, Anthony J, McKinlay, Bruce W
- Authors: Booth, Anthony J , McKinlay, Bruce W
- Date: 2001
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127020 , vital:35944 , https://doi.10.1080/15627020.2001.11657111
- Description: The Okavango Delta is a vast inland wetland system situated in northern Botswana. High rainfall is received in early summer in the southern Angolan highlands and throughout the Delta with the flood waters reaching the upper riverine floodplain between March and May where it percolates through to the lower drainage rivers between July and September. Aspects of the reproductive and feeding biology of two allopatric populations of the striped robber, Brycinus lateralis, a small characin species inhabiting the northern riverine floodplain and southern drainage rivers, were investigated. Both populations were similar in the biological aspects studied, with the flood cycle having little influence on the timing of reproduction, sexual maturity and dietary composition. Female fish from both populations matured sexually at 57mmSL, breeding over a protracted period during the warm, summer months. In both populations, the sex ratio was female-dominated at 4.8:1 (riverine floodplain) and 2.2:1 (drainage rivers). The striped robber is an opportunistic micro-carnivore with immature fish feeding predominantly on Daphnia spp. and adults being largely insectivorous.
- Full Text:
- Date Issued: 2001
- Authors: Booth, Anthony J , McKinlay, Bruce W
- Date: 2001
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127020 , vital:35944 , https://doi.10.1080/15627020.2001.11657111
- Description: The Okavango Delta is a vast inland wetland system situated in northern Botswana. High rainfall is received in early summer in the southern Angolan highlands and throughout the Delta with the flood waters reaching the upper riverine floodplain between March and May where it percolates through to the lower drainage rivers between July and September. Aspects of the reproductive and feeding biology of two allopatric populations of the striped robber, Brycinus lateralis, a small characin species inhabiting the northern riverine floodplain and southern drainage rivers, were investigated. Both populations were similar in the biological aspects studied, with the flood cycle having little influence on the timing of reproduction, sexual maturity and dietary composition. Female fish from both populations matured sexually at 57mmSL, breeding over a protracted period during the warm, summer months. In both populations, the sex ratio was female-dominated at 4.8:1 (riverine floodplain) and 2.2:1 (drainage rivers). The striped robber is an opportunistic micro-carnivore with immature fish feeding predominantly on Daphnia spp. and adults being largely insectivorous.
- Full Text:
- Date Issued: 2001
Phloem loading in the sucrose-export-defective (SXD-1) mutant maize is limited by callose deposition at plasmodesmata in bundle sheath-vascular parenchyma interface
- Botha, Christiaan E J, Cross, Robin H M, Van Bel, A J E, Peter, Craig I
- Authors: Botha, Christiaan E J , Cross, Robin H M , Van Bel, A J E , Peter, Craig I
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6503 , http://hdl.handle.net/10962/d1005926
- Description: Using Lucifer Yellow we have demonstrated that the phloem-loading pathway from the mesophyll to the bundle sheath-vascular parenchyma interface in Zea mays source leaves follows a symplasmic route in small and intermediate vascular bundles in control as well as in the green sections of mutant sucrose-export-defective (SXD-1) plants. In the anthocyanin-rich mutant leaf sections, Lucifer Yellow transport was prohibited along the same path, at the bundle sheath-vascular parenchyma interface in particular. Plasmodesmata at the latter interface in SXD-1 anthocyanin-rich leaf sections appear to be structurally altered through callose deposition at the plasmodesmal orifices. We suggest that a transport bottleneck at the bundle sheath-vascular parenchyma interface is thus orchestrated and regulated through callose formation, preventing symplasmic transport across this important loading interface.
- Full Text:
- Date Issued: 2000
- Authors: Botha, Christiaan E J , Cross, Robin H M , Van Bel, A J E , Peter, Craig I
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6503 , http://hdl.handle.net/10962/d1005926
- Description: Using Lucifer Yellow we have demonstrated that the phloem-loading pathway from the mesophyll to the bundle sheath-vascular parenchyma interface in Zea mays source leaves follows a symplasmic route in small and intermediate vascular bundles in control as well as in the green sections of mutant sucrose-export-defective (SXD-1) plants. In the anthocyanin-rich mutant leaf sections, Lucifer Yellow transport was prohibited along the same path, at the bundle sheath-vascular parenchyma interface in particular. Plasmodesmata at the latter interface in SXD-1 anthocyanin-rich leaf sections appear to be structurally altered through callose deposition at the plasmodesmal orifices. We suggest that a transport bottleneck at the bundle sheath-vascular parenchyma interface is thus orchestrated and regulated through callose formation, preventing symplasmic transport across this important loading interface.
- Full Text:
- Date Issued: 2000
Towards reconciliation of structure with function in plasmodesmata—who is the gatekeeper?
- Botha, Christiaan E J, Cross, Robin H M
- Authors: Botha, Christiaan E J , Cross, Robin H M
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6497 , http://hdl.handle.net/10962/d1004493
- Description: Whilst the structure of higher plant plasmodesmata was first described by Robards (1963. Desmotubule—a plasmodesmatal substructure. Nature 218, 784), and despite many subsequent intensive investigations, there is still much that remains unclear relating to their ultrastructure and functioning in higher plants. We have examined chemically fixed plant material, and suggest that the conformational changes seen in plasmodesmatal substructure, particularly the deposition of electron-dense extra-plasmodesmal material, is linked to either manipulation of the hormonal balance (as in Avocado fruit), or of osmotic potential in leaf blade material. These changes result in the deposition of β 1,3-glucan (callose) at the neck region of these plasmodesmata. This electron-dense material is deposited at the neck region of plasmodesmata, and forms a collar-like structure. The formation of a collar is shown to be coupled with loss of lucence within the cytoplasmic sleeve. The formation of a collar at the plasmodesmatal orifice thus results in encapsulation and closure of the plasmodesmatal orifice. Closure of the orifice coincides with a loss of electron-lucence and a lack of resolution of the desmotubule. These ultrastructural changes are potentially significant and could contribute to, result in, or assist in the down-regulation of cell to cell trafficking via plasmodesmata.
- Full Text:
- Date Issued: 2000
- Authors: Botha, Christiaan E J , Cross, Robin H M
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6497 , http://hdl.handle.net/10962/d1004493
- Description: Whilst the structure of higher plant plasmodesmata was first described by Robards (1963. Desmotubule—a plasmodesmatal substructure. Nature 218, 784), and despite many subsequent intensive investigations, there is still much that remains unclear relating to their ultrastructure and functioning in higher plants. We have examined chemically fixed plant material, and suggest that the conformational changes seen in plasmodesmatal substructure, particularly the deposition of electron-dense extra-plasmodesmal material, is linked to either manipulation of the hormonal balance (as in Avocado fruit), or of osmotic potential in leaf blade material. These changes result in the deposition of β 1,3-glucan (callose) at the neck region of these plasmodesmata. This electron-dense material is deposited at the neck region of plasmodesmata, and forms a collar-like structure. The formation of a collar is shown to be coupled with loss of lucence within the cytoplasmic sleeve. The formation of a collar at the plasmodesmatal orifice thus results in encapsulation and closure of the plasmodesmatal orifice. Closure of the orifice coincides with a loss of electron-lucence and a lack of resolution of the desmotubule. These ultrastructural changes are potentially significant and could contribute to, result in, or assist in the down-regulation of cell to cell trafficking via plasmodesmata.
- Full Text:
- Date Issued: 2000
Environmental youth clubs in Namibia : what role do, could or should they play in environmental education?
- Authors: Botma, Connie
- Date: 2000
- Subjects: Environmental education -- Namibia Environmental education -- Study and teaching -- Namibia Youth -- Societies and clubs Youth -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1519 , http://hdl.handle.net/10962/d1003401
- Description: Although the existence of wildlife clubs in Africa dates back to the start of the environmental movement in the 1970s, youth involvement through environmental clubs only commenced in Namibia in 1992. I became involved with the clubs in 1995 when I was employed by the Rossing Foundation Environmental Education Project to encourage, support and coordinate environmental clubs in Namibia. During the last three years the number of Namibian clubs has increased from 20 to ±85, and they are now established in most geographical regions of the country. During my involvement with the clubs I became increasingly interested in the philosophical underpinnings of youth movements like clubs and started questioning what we could expect from the youth and what could be achieved through the clubs. One of my main concerns was whether youth could make a significant improvement to the quality of their lives and their environment through these clubs. The aim of my research was therefore to describe and reflect critically on the role of environmental youth clubs in environmental education in Namibia. My study was guided by a socially critical orientation which emphasises the construction of meaning through social dialogue and critical reflection. I chose an interpretative research strategy and generated data mainly through semi-structured interviews, participant observation, a focus-group discussion and a workshop. Due to the focus of the research I purposefully selected the sample of existing youth clubs to be included in the study. The iterative strategy of gathering and interpreting data in successive cycles allowed for continuous reflection throughout the research process. It also allowed me to identify key patterns and trends in analysing and interpreting the data. The study findings suggest that environmental clubs do playa role in learning about environmental issues; in developing personal and social identity, confidence and a sense of purpose in society; in establishing new and supportive relationships between teachers and learners and with other community resourde people; in creating opportunities and enabling exposure to diverse learning environments, options and alternatives; and ih fostering the orientation and skills needed to effect meaningful d1'inges in the environment. The findings also suggest that environmental clubs could make a significant contribution to environmental education, providing that they incorporate a socially critical orientation, gain greater recognition from significant adults and education officials, collaborate with other projects and organisations, and use guidelines of models such as the action research framework to ensure relevant and effective action projects. The main challenges to environmental clubs in Namibia include changing perceptions that youth do not have much to contribute; improving relationships between clubs, schools and communities; dealing with the tension between the possible disempowering effect of central control and the need for more formalised structures in order to gain official recognition; and developing strategies to ensure the clubs' sustainability in the future.
- Full Text:
- Date Issued: 2000
- Authors: Botma, Connie
- Date: 2000
- Subjects: Environmental education -- Namibia Environmental education -- Study and teaching -- Namibia Youth -- Societies and clubs Youth -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1519 , http://hdl.handle.net/10962/d1003401
- Description: Although the existence of wildlife clubs in Africa dates back to the start of the environmental movement in the 1970s, youth involvement through environmental clubs only commenced in Namibia in 1992. I became involved with the clubs in 1995 when I was employed by the Rossing Foundation Environmental Education Project to encourage, support and coordinate environmental clubs in Namibia. During the last three years the number of Namibian clubs has increased from 20 to ±85, and they are now established in most geographical regions of the country. During my involvement with the clubs I became increasingly interested in the philosophical underpinnings of youth movements like clubs and started questioning what we could expect from the youth and what could be achieved through the clubs. One of my main concerns was whether youth could make a significant improvement to the quality of their lives and their environment through these clubs. The aim of my research was therefore to describe and reflect critically on the role of environmental youth clubs in environmental education in Namibia. My study was guided by a socially critical orientation which emphasises the construction of meaning through social dialogue and critical reflection. I chose an interpretative research strategy and generated data mainly through semi-structured interviews, participant observation, a focus-group discussion and a workshop. Due to the focus of the research I purposefully selected the sample of existing youth clubs to be included in the study. The iterative strategy of gathering and interpreting data in successive cycles allowed for continuous reflection throughout the research process. It also allowed me to identify key patterns and trends in analysing and interpreting the data. The study findings suggest that environmental clubs do playa role in learning about environmental issues; in developing personal and social identity, confidence and a sense of purpose in society; in establishing new and supportive relationships between teachers and learners and with other community resourde people; in creating opportunities and enabling exposure to diverse learning environments, options and alternatives; and ih fostering the orientation and skills needed to effect meaningful d1'inges in the environment. The findings also suggest that environmental clubs could make a significant contribution to environmental education, providing that they incorporate a socially critical orientation, gain greater recognition from significant adults and education officials, collaborate with other projects and organisations, and use guidelines of models such as the action research framework to ensure relevant and effective action projects. The main challenges to environmental clubs in Namibia include changing perceptions that youth do not have much to contribute; improving relationships between clubs, schools and communities; dealing with the tension between the possible disempowering effect of central control and the need for more formalised structures in order to gain official recognition; and developing strategies to ensure the clubs' sustainability in the future.
- Full Text:
- Date Issued: 2000
Red Clay
- Boubacar N'Dour, Prince Charles Alexander, Youssou N'Dour (written by), Youssou N'Dour (vocal), Habib Faye (bass), Manu Katche (drums), Jimi Mbaye, Pape Oumar Ngom (guitar), Babacar Faye (Senegalese percussion), Jerome Lemmier (keyboards, arranger, programmer), Assane Thiam (sabar talking drum), Pierre Bianchi
- Authors: Boubacar N'Dour, Prince Charles Alexander, Youssou N'Dour (written by) , Youssou N'Dour (vocal) , Habib Faye (bass) , Manu Katche (drums) , Jimi Mbaye, Pape Oumar Ngom (guitar) , Babacar Faye (Senegalese percussion) , Jerome Lemmier (keyboards, arranger, programmer) , Assane Thiam (sabar talking drum) , Pierre Bianchi
- Date: 2000
- Subjects: Rhythm and blues music , Popular music--Africa, West , Africa Senegal Dakar f-sg
- Language: English , Wolof
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/130534 , vital:36434 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC44-04
- Description: Fusion of Senegalese desert music and Western rhythm and blues
- Full Text: false
- Date Issued: 2000
- Authors: Boubacar N'Dour, Prince Charles Alexander, Youssou N'Dour (written by) , Youssou N'Dour (vocal) , Habib Faye (bass) , Manu Katche (drums) , Jimi Mbaye, Pape Oumar Ngom (guitar) , Babacar Faye (Senegalese percussion) , Jerome Lemmier (keyboards, arranger, programmer) , Assane Thiam (sabar talking drum) , Pierre Bianchi
- Date: 2000
- Subjects: Rhythm and blues music , Popular music--Africa, West , Africa Senegal Dakar f-sg
- Language: English , Wolof
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/130534 , vital:36434 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC44-04
- Description: Fusion of Senegalese desert music and Western rhythm and blues
- Full Text: false
- Date Issued: 2000
She doesn't need to fall
- Boubacar N'Dour, Prince Charles Alexander, Youssou N'Dour (written by), Youssou N'Dour (vocal), Habib Faye (bass), Manu Katche (drums), Jimi Mbaye, Pape Oumar Ngom (guitar), Babacar Faye (Senegalese percussion), Jerome Lemmier (keyboards, arranger, programmer), Assane Thiam (sabar talking drum), Pierre Bianchi
- Authors: Boubacar N'Dour, Prince Charles Alexander, Youssou N'Dour (written by) , Youssou N'Dour (vocal) , Habib Faye (bass) , Manu Katche (drums) , Jimi Mbaye, Pape Oumar Ngom (guitar) , Babacar Faye (Senegalese percussion) , Jerome Lemmier (keyboards, arranger, programmer) , Assane Thiam (sabar talking drum) , Pierre Bianchi
- Date: 2000
- Subjects: Rhythm and blues music , Popular music--Africa, West , Africa Senegal Dakar f-sg
- Language: English , Wolof
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/130519 , vital:36433 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC44-03
- Description: Fusion of Senegalese desert music and Western rhythm and blues
- Full Text: false
- Date Issued: 2000
- Authors: Boubacar N'Dour, Prince Charles Alexander, Youssou N'Dour (written by) , Youssou N'Dour (vocal) , Habib Faye (bass) , Manu Katche (drums) , Jimi Mbaye, Pape Oumar Ngom (guitar) , Babacar Faye (Senegalese percussion) , Jerome Lemmier (keyboards, arranger, programmer) , Assane Thiam (sabar talking drum) , Pierre Bianchi
- Date: 2000
- Subjects: Rhythm and blues music , Popular music--Africa, West , Africa Senegal Dakar f-sg
- Language: English , Wolof
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/130519 , vital:36433 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC44-03
- Description: Fusion of Senegalese desert music and Western rhythm and blues
- Full Text: false
- Date Issued: 2000
Multiple metaphors in an understanding of academic literacy
- Authors: Boughey, Chrissie
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6088 , http://hdl.handle.net/10962/d1008587
- Description: This article describes understandings derived from work in a first year Systematic Philosophy class at a historically black South African university which challenge the assumptions on which the writer has based her practice as a teacher of English as a second language for many years. These assumptions focus on the perception of problems related to the production and reception of academic texts as solely, or even mainly, linguistic in origin. Analysis of writing and interviews with students suggests that the problems in the writing stem mainly from their unfamiliarity with academic discourses in spite of the fact that all are speakers of English as an additional language.
- Full Text:
- Date Issued: 2000
- Authors: Boughey, Chrissie
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6088 , http://hdl.handle.net/10962/d1008587
- Description: This article describes understandings derived from work in a first year Systematic Philosophy class at a historically black South African university which challenge the assumptions on which the writer has based her practice as a teacher of English as a second language for many years. These assumptions focus on the perception of problems related to the production and reception of academic texts as solely, or even mainly, linguistic in origin. Analysis of writing and interviews with students suggests that the problems in the writing stem mainly from their unfamiliarity with academic discourses in spite of the fact that all are speakers of English as an additional language.
- Full Text:
- Date Issued: 2000
Visual literacy in adult basic education : a study of ABET learners' visual perception with regard to their general level of English second language learning
- Authors: Bouwer, Anne Margaret
- Date: 2000
- Subjects: English language -- Study and teaching (Secondary) -- Foreign speakers Visual literacy -- South Africa Adult education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1821 , http://hdl.handle.net/10962/d1003707
- Description: Adult learners face many difficulties in their learning programmes, particularly due to the fact that having mastered literacy in their mother tongues, they move on to further educational programmes which are mostly produced in English. In contemporary society, people need to be adept in a number of literacies, termed multiliteracies. Adult learners are rarely taught visual competence as visual images are relegated to illustrations for written texts, and attention is mainly focussed on the all-important written word. Adult basic education learners need to be able to interpret pictures in books, newspapers and magazines, just as much as they need to be able to read and write. It is the premise of this research that visual literacy enhances thinking skills and that adult learners need to be actively taught how to interpret visual images in order to more ably deal with the written word, the more 'important' part of literacy. The goals of this research are to develop understanding of the processes which go into understanding images and text, and to examine how pictures can be used to help adult learners develop proficiency in English. Another goal is to teach learners the basics of visual literacy so as to improve their comprehension of the plethora of images surrounding them. The research findings could help to inform adult educators facing the current crisis in Adult Basic Education and Training in South Africa, focusing on a little-studied aspect of literacy, visual literacy, one of the critical outcomes in the new South African curriculum for Adult Education and one of the multiliteracies required by citizens of today's world.
- Full Text:
- Date Issued: 2000
- Authors: Bouwer, Anne Margaret
- Date: 2000
- Subjects: English language -- Study and teaching (Secondary) -- Foreign speakers Visual literacy -- South Africa Adult education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1821 , http://hdl.handle.net/10962/d1003707
- Description: Adult learners face many difficulties in their learning programmes, particularly due to the fact that having mastered literacy in their mother tongues, they move on to further educational programmes which are mostly produced in English. In contemporary society, people need to be adept in a number of literacies, termed multiliteracies. Adult learners are rarely taught visual competence as visual images are relegated to illustrations for written texts, and attention is mainly focussed on the all-important written word. Adult basic education learners need to be able to interpret pictures in books, newspapers and magazines, just as much as they need to be able to read and write. It is the premise of this research that visual literacy enhances thinking skills and that adult learners need to be actively taught how to interpret visual images in order to more ably deal with the written word, the more 'important' part of literacy. The goals of this research are to develop understanding of the processes which go into understanding images and text, and to examine how pictures can be used to help adult learners develop proficiency in English. Another goal is to teach learners the basics of visual literacy so as to improve their comprehension of the plethora of images surrounding them. The research findings could help to inform adult educators facing the current crisis in Adult Basic Education and Training in South Africa, focusing on a little-studied aspect of literacy, visual literacy, one of the critical outcomes in the new South African curriculum for Adult Education and one of the multiliteracies required by citizens of today's world.
- Full Text:
- Date Issued: 2000
An investigation into dopamine-melatonin interactions in the rat Corpus striatum and pineal gland: a possible pineal-striatal axis
- Authors: Boyd, Clinton Shane
- Date: 2000
- Subjects: Pineal gland -- Research Melatonin Dopamine -- Physiological effect Dopamine Brain chemistry Rats -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3906 , http://hdl.handle.net/10962/d1003965
- Description: Dysfunction of central dopaminergic systems has been implicated in neuroendocrine, neurodegenerative and psychiatric disorders. Monoamine oxidase and catechol-Omethyltransferase represent the key catabolic enzymes of dopamine, terminating neurotransmission following synaptic release of this catecholamine. Thus, both enzymes have been associated with the pathology of dopaminergic systems and represent therapeutic targets elf enormous clinical importance. Some neuroendocrine and circadian effects of melatonin have been attributed to an antidopamimetic effect of this pineal hormone in the hypothalamus and pituitary. Furthermore, both melatonin and dopamine modulate the behavioural output of the mesencephalic dopaminergic pathways of the basal ganglia, including movement disorders. However, the biochemical basis for the tonic inhibitory effect of melatonin in the nigro-striatal pathway has been poorly delineated. Thus, this study determined whether melatonin influences dopaminergic function in the corpus striatum of the Wistar rat by modulating monoamine oxidase and catecholO- methyltransferase activity. Reciprocally, the putative existence of an intrapineal dopaminergic system was investigated by determining the effect of selective dopaminergic agents, R-( -)apomorphine, haloperidol and dopamine, on indole metabolism of the pineal gland. The akinetic state of drug-induced catalepsy was employed as an animal model of Parkinson's disease to probe the neurotransmitter systems involved in the behavioural effects of melatonin. Indole metabolism was a reliable indicator of state-dependent metabolic fluxes in pineal gland function. These included a robust diurnal and seasonal variation in N-acetylserotonin and melatonin biosynthesis, and photoperiod- and drug-induced alterations of Inftabolism. The predominant changes could be attributed to an effect on serotonin N-acetyltransferase activity and/or the melatoninl5-methoxytryptophol ratio. Pineal 5-methoxyindole biosynthesis was determined primarily by the bioavailability of the corresponding 5-hydroxyindole and its affinity for hydroxyindole-O-methyltransferase. Evidence was found for the negative feedback or paracrine control of pineal indole metabolism by melatonin. A high inter-individual variability was observed in the biosynthesis of N-acetylserotonin and melatonin biosynthesis, and the weight of the pineal glands. Accordingly, the rats could be classified as either high or low capacity producers of these two indoles. R-(-)-apomorphine and dopamine in vitro, but not acute haloperidol in vivo, had dose- and phase-dependent effects on pineal indole metabolism. The predominant effect was a suppression of the scotophase-dependent induction ofN-acetylserotonin and melatonin biosynthesis by dopamine and R-( -)-apomorphine. It is postulated that these agonists inhibited nocturnal N-acetyltransferase activity via postsynaptic pineal D2 or D2-like receptors. The observed modulatory nature of the intrapineal dopaminergic system suggests that dopamine may be involved in the long-term regulation of pineal indole biosynthesis. Several lines of evidence are presented that the activity of striatal monoamine oxidase A and catechol-O-methyltransferase, represented predominantly by the soluble isoform, is statedependent and regulated in vivo by endogenous melatonin. Firstly, both enzymes showed a daynight variation in activity. Secondly, acute and subchronic administration and photoperiod manipulation studies indicated that both exogenous and endogenous melatonin inhibited each enzyme in a chronotypic fashion, with a more robust effect against catechol- -methyltransferase. The intensity of the in vivo effects was critically dependent on the dose, duration, route and the phase-timing of administration during the light dark cycle, and the length of the exposure to constant light. Melatonin in vitro had no effect on basal or Mg2+ -induced catechol-Omethyltransferase activity. Thus, it is proposed that the in vivo effects of the hormone can be attributed to a time-dependent change in the amount of active molecules of this enzyme. In contrast, melatonin and numerous other endogenous indolic compounds were found to be reversible inhibitors of striatal monoamine oxidase A in vitro. Structure-activity modeling revealed that the 5-methoxy moiety on the indole nucleus and substitution of the free primary amine of these compounds were the principal determinants of the potency and time-dependency of inhibition. Thus melatonin most likely has a direct inhibitory effect in vivo at the level of the active site of monoamine oxidase A. Exogenous melatonin alone had no cataleptogenic potential whereas a variety of behavioural responses were observed following intraperitoneal administration of y-hydroxybutyrate. The latter responses were state-dependent with day-night variations in intensity. Furthermore, yhydroxybutyrate stimulated melatonin biosynthesis during the photophase both in vitro and in vivo. These results point to a possible involvement of melatonin in the behavioural and neurochemical effects of y-hydroxybutyrate. Thus the general conclusion is that dopamine and melatonin display functional antagonism at the level of the pineal gland and corpus striatum of the Wistar rats. Therefore melatonin may be an important homeostatic modulator of dopaminergic neurotransmission throu~out the central nervous system. Furthermore, the putative existence of a functional pineal-striatal axis would greatly strengthen the argument for a holistic concept of brain homeostasis. The ability of endogenous melatonin to regulate monoamine oxidase A and catechol-O-methyltransferase may represent an alternative strategy for the treatment of disorders associated with these enzymes.
- Full Text:
- Date Issued: 2000
- Authors: Boyd, Clinton Shane
- Date: 2000
- Subjects: Pineal gland -- Research Melatonin Dopamine -- Physiological effect Dopamine Brain chemistry Rats -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3906 , http://hdl.handle.net/10962/d1003965
- Description: Dysfunction of central dopaminergic systems has been implicated in neuroendocrine, neurodegenerative and psychiatric disorders. Monoamine oxidase and catechol-Omethyltransferase represent the key catabolic enzymes of dopamine, terminating neurotransmission following synaptic release of this catecholamine. Thus, both enzymes have been associated with the pathology of dopaminergic systems and represent therapeutic targets elf enormous clinical importance. Some neuroendocrine and circadian effects of melatonin have been attributed to an antidopamimetic effect of this pineal hormone in the hypothalamus and pituitary. Furthermore, both melatonin and dopamine modulate the behavioural output of the mesencephalic dopaminergic pathways of the basal ganglia, including movement disorders. However, the biochemical basis for the tonic inhibitory effect of melatonin in the nigro-striatal pathway has been poorly delineated. Thus, this study determined whether melatonin influences dopaminergic function in the corpus striatum of the Wistar rat by modulating monoamine oxidase and catecholO- methyltransferase activity. Reciprocally, the putative existence of an intrapineal dopaminergic system was investigated by determining the effect of selective dopaminergic agents, R-( -)apomorphine, haloperidol and dopamine, on indole metabolism of the pineal gland. The akinetic state of drug-induced catalepsy was employed as an animal model of Parkinson's disease to probe the neurotransmitter systems involved in the behavioural effects of melatonin. Indole metabolism was a reliable indicator of state-dependent metabolic fluxes in pineal gland function. These included a robust diurnal and seasonal variation in N-acetylserotonin and melatonin biosynthesis, and photoperiod- and drug-induced alterations of Inftabolism. The predominant changes could be attributed to an effect on serotonin N-acetyltransferase activity and/or the melatoninl5-methoxytryptophol ratio. Pineal 5-methoxyindole biosynthesis was determined primarily by the bioavailability of the corresponding 5-hydroxyindole and its affinity for hydroxyindole-O-methyltransferase. Evidence was found for the negative feedback or paracrine control of pineal indole metabolism by melatonin. A high inter-individual variability was observed in the biosynthesis of N-acetylserotonin and melatonin biosynthesis, and the weight of the pineal glands. Accordingly, the rats could be classified as either high or low capacity producers of these two indoles. R-(-)-apomorphine and dopamine in vitro, but not acute haloperidol in vivo, had dose- and phase-dependent effects on pineal indole metabolism. The predominant effect was a suppression of the scotophase-dependent induction ofN-acetylserotonin and melatonin biosynthesis by dopamine and R-( -)-apomorphine. It is postulated that these agonists inhibited nocturnal N-acetyltransferase activity via postsynaptic pineal D2 or D2-like receptors. The observed modulatory nature of the intrapineal dopaminergic system suggests that dopamine may be involved in the long-term regulation of pineal indole biosynthesis. Several lines of evidence are presented that the activity of striatal monoamine oxidase A and catechol-O-methyltransferase, represented predominantly by the soluble isoform, is statedependent and regulated in vivo by endogenous melatonin. Firstly, both enzymes showed a daynight variation in activity. Secondly, acute and subchronic administration and photoperiod manipulation studies indicated that both exogenous and endogenous melatonin inhibited each enzyme in a chronotypic fashion, with a more robust effect against catechol- -methyltransferase. The intensity of the in vivo effects was critically dependent on the dose, duration, route and the phase-timing of administration during the light dark cycle, and the length of the exposure to constant light. Melatonin in vitro had no effect on basal or Mg2+ -induced catechol-Omethyltransferase activity. Thus, it is proposed that the in vivo effects of the hormone can be attributed to a time-dependent change in the amount of active molecules of this enzyme. In contrast, melatonin and numerous other endogenous indolic compounds were found to be reversible inhibitors of striatal monoamine oxidase A in vitro. Structure-activity modeling revealed that the 5-methoxy moiety on the indole nucleus and substitution of the free primary amine of these compounds were the principal determinants of the potency and time-dependency of inhibition. Thus melatonin most likely has a direct inhibitory effect in vivo at the level of the active site of monoamine oxidase A. Exogenous melatonin alone had no cataleptogenic potential whereas a variety of behavioural responses were observed following intraperitoneal administration of y-hydroxybutyrate. The latter responses were state-dependent with day-night variations in intensity. Furthermore, yhydroxybutyrate stimulated melatonin biosynthesis during the photophase both in vitro and in vivo. These results point to a possible involvement of melatonin in the behavioural and neurochemical effects of y-hydroxybutyrate. Thus the general conclusion is that dopamine and melatonin display functional antagonism at the level of the pineal gland and corpus striatum of the Wistar rats. Therefore melatonin may be an important homeostatic modulator of dopaminergic neurotransmission throu~out the central nervous system. Furthermore, the putative existence of a functional pineal-striatal axis would greatly strengthen the argument for a holistic concept of brain homeostasis. The ability of endogenous melatonin to regulate monoamine oxidase A and catechol-O-methyltransferase may represent an alternative strategy for the treatment of disorders associated with these enzymes.
- Full Text:
- Date Issued: 2000
Mefie-toi (remix maquis)
- Brighess (author, composer, lead singer, chorus, percussions), Turbo (chorus), Le Ziboua Stars (band), Cisky de Panza (chorus, guitar, arranger), Ras live I
- Authors: Brighess (author, composer, lead singer, chorus, percussions) , Turbo (chorus) , Le Ziboua Stars (band) , Cisky de Panza (chorus, guitar, arranger) , Ras live I
- Date: 2000
- Subjects: Popular music , Popular music--Africa, West , Africa Guinea Conakry f-gv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129315 , vital:36261 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC20-09
- Description: Male vocal group sing in traditional Guinean harmonies and sounds, accompanied by percussion, keyboard, bass and striking bell, overlaid with modern afrobeat rhythm
- Full Text: false
- Date Issued: 2000
- Authors: Brighess (author, composer, lead singer, chorus, percussions) , Turbo (chorus) , Le Ziboua Stars (band) , Cisky de Panza (chorus, guitar, arranger) , Ras live I
- Date: 2000
- Subjects: Popular music , Popular music--Africa, West , Africa Guinea Conakry f-gv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129315 , vital:36261 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC20-09
- Description: Male vocal group sing in traditional Guinean harmonies and sounds, accompanied by percussion, keyboard, bass and striking bell, overlaid with modern afrobeat rhythm
- Full Text: false
- Date Issued: 2000
Elle est occupee (remix maquis)
- Brighess (author, composer, lead singer, chorus, percussions), Turbo (chorus), Le Ziboua Stars (band), Cisky de Panza (chorus, guitar, arranger), Ras live I
- Authors: Brighess (author, composer, lead singer, chorus, percussions) , Turbo (chorus) , Le Ziboua Stars (band) , Cisky de Panza (chorus, guitar, arranger) , Ras live I
- Date: 2000
- Subjects: Popular music , Popular music--Africa, West , Africa Guinea Conakry f-gv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129305 , vital:36259 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC20-07
- Description: Male vocal group sing in traditional Guinean harmonies and sounds, accompanied by percussion, keyboard, bass and striking bell, overlaid with modern afrobeat rhythm
- Full Text: false
- Date Issued: 2000
- Authors: Brighess (author, composer, lead singer, chorus, percussions) , Turbo (chorus) , Le Ziboua Stars (band) , Cisky de Panza (chorus, guitar, arranger) , Ras live I
- Date: 2000
- Subjects: Popular music , Popular music--Africa, West , Africa Guinea Conakry f-gv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129305 , vital:36259 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC20-07
- Description: Male vocal group sing in traditional Guinean harmonies and sounds, accompanied by percussion, keyboard, bass and striking bell, overlaid with modern afrobeat rhythm
- Full Text: false
- Date Issued: 2000
Reviens
- Brighess (author, composer, lead singer, chorus, percussions), Turbo (chorus), Le Ziboua Stars (band), Cisky de Panza (chorus, guitar, arranger), Ras live I
- Authors: Brighess (author, composer, lead singer, chorus, percussions) , Turbo (chorus) , Le Ziboua Stars (band) , Cisky de Panza (chorus, guitar, arranger) , Ras live I
- Date: 2000
- Subjects: Popular music , Popular music--Africa, West , Africa Guinea Conakry f-gv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129284 , vital:36257 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC20-06
- Description: Male vocal group sing in traditional Guinean harmonies and sounds, accompanied by percussion, keyboard, bass and striking bell, overlaid with modern afrobeat rhythm
- Full Text: false
- Date Issued: 2000
- Authors: Brighess (author, composer, lead singer, chorus, percussions) , Turbo (chorus) , Le Ziboua Stars (band) , Cisky de Panza (chorus, guitar, arranger) , Ras live I
- Date: 2000
- Subjects: Popular music , Popular music--Africa, West , Africa Guinea Conakry f-gv
- Language: French
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/129284 , vital:36257 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDC20-06
- Description: Male vocal group sing in traditional Guinean harmonies and sounds, accompanied by percussion, keyboard, bass and striking bell, overlaid with modern afrobeat rhythm
- Full Text: false
- Date Issued: 2000