The use of interactive computer simulations to engender conceptual changes about wave motion
- Authors: Jacob, Sunny
- Date: 2001
- Subjects: Computer simulation
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1921 , http://hdl.handle.net/10962/d1007409
- Description: Computers are expensive equipment which most schools in South Africa cannot afford to use as an instructional tool in the same way as they are being used in affluent schools in the countly and in the western world. In this study a computer was used as a demonstration tool to help learners to visualise the different aspects of wave motion with the aid of interactive computer simulations. The study investigated how learners alter their intuitive notions of wave motion after experiencing the common teaching techniques in township schools, and then by observing interactive computer simulations. Data was collected by means of field notes, observation, questionnaires and in-depth semi-structured interviews with the participation of twelve Grade 9 learners in a secondary school over a three-week period. A combination of qualitative and quantitative methods was used in the study and the data was analysed within an interpretive framework. A detailed analysis revealed that interactive computer simulations could bring about positive conceptual changes in learners, especially in the micro level aspects of wave motion. The inexperience of the learners in a discovery method of learning and a learner centred approach of teaching seemed to interfere with the teaching techniques. To a considerable extent, language problems also hindered the revelation of conceptualisation.In writing this report of the research study J agree wilh Squires and McDougall (1994: 12) that it is difficult to use a non-interactive medium (paper-based text) to report on the interactive medium of computer simulations, as written words cannot bring out all the essential aspects of interactive computer simulations.
- Full Text:
- Date Issued: 2001
- Authors: Jacob, Sunny
- Date: 2001
- Subjects: Computer simulation
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1921 , http://hdl.handle.net/10962/d1007409
- Description: Computers are expensive equipment which most schools in South Africa cannot afford to use as an instructional tool in the same way as they are being used in affluent schools in the countly and in the western world. In this study a computer was used as a demonstration tool to help learners to visualise the different aspects of wave motion with the aid of interactive computer simulations. The study investigated how learners alter their intuitive notions of wave motion after experiencing the common teaching techniques in township schools, and then by observing interactive computer simulations. Data was collected by means of field notes, observation, questionnaires and in-depth semi-structured interviews with the participation of twelve Grade 9 learners in a secondary school over a three-week period. A combination of qualitative and quantitative methods was used in the study and the data was analysed within an interpretive framework. A detailed analysis revealed that interactive computer simulations could bring about positive conceptual changes in learners, especially in the micro level aspects of wave motion. The inexperience of the learners in a discovery method of learning and a learner centred approach of teaching seemed to interfere with the teaching techniques. To a considerable extent, language problems also hindered the revelation of conceptualisation.In writing this report of the research study J agree wilh Squires and McDougall (1994: 12) that it is difficult to use a non-interactive medium (paper-based text) to report on the interactive medium of computer simulations, as written words cannot bring out all the essential aspects of interactive computer simulations.
- Full Text:
- Date Issued: 2001
The vegetation potential of natural rangelands in the mid-Fish River Valley, Eastern Cape, South Africa: towards a sustainable and acceptable management system
- Birch, Natalie Vivienne Evans
- Authors: Birch, Natalie Vivienne Evans
- Date: 2001
- Subjects: Vegetation and climate -- South Africa -- Eastern Cape Vegetation dynamics -- South Africa -- Eastern Cape Vegetation surveys -- South Africa -- Eastern Cape Land -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4186 , http://hdl.handle.net/10962/d1003754
- Description: Desertification is the diminution or destruction of the biological potential of land, and can lead ultimately to desert-like conditions. The vegetation of southern Africa is claimed to have altered over the past 100 years and much of the change is attributed to pastoral practice. In recent years however there has been much debate around the issue of the deterioration and loss of productivity of the natural rangelands, specifically those under communal management. It is one thing to claim that the vegetation has changed but quite another to produce data and analyses to show this unequivocally. Furthermore it is generally difficult to determine the nature and extent of change in natural ecosystems, as one does not know what the optimal base-line conditions should be. For this reason emphasis has been placed on developing models of potential or expected vegetation. By comparing a model of potential or expected vegetation with that of the contemporary vegetation, areas that deviate from expectation can be identified, in so doing providing evidence of the direction of change in the rangelands under various management treatments. The objective of this study was to determine shifts in the vegetation under different land-use treatments, by developing a technique to predict the potential vegetation of an area. In order to explore the nature and extent of degradation at the landscape scale a study site was selected where a range of land-use and rangeland management practices could be studied in parallel. The mid-Fish River valley consists of three markedly different units of land management, namely commercial rangelands, communal rangelands and nature conservation areas. The vegetation within the mid-Fish River valley falls within the Thicket biome and consists of three main vegetation types namely, Short Succulent Thicket, Medium Succulent Thicket and Mesic Bushclump Savanna. The creation of this potential vegetation model was dependent on the direct gradient analysis approach of relating the community patterns with environmental variables. To achieve this, floristic information was collected at sites along a topographical-moisture gradient. A Canonical Correspondence Analysis (CCA) between the environmental variables and the plant communities produced a classification from which the conditions normally associated with the major plant communities were predicted. When projected as a digital map, the qualifying sites provided a testable hypothesis of the potential vegetation. The results of this study showed a definite grazing gradient, which reflects a change from a more mesic environment towards a more arid environment with an increase in utilisation pressure. The predictive vegetation model proved to be useful for predicting the occurrence of the valley thicket communities within the Eastern Cape.
- Full Text:
- Date Issued: 2001
- Authors: Birch, Natalie Vivienne Evans
- Date: 2001
- Subjects: Vegetation and climate -- South Africa -- Eastern Cape Vegetation dynamics -- South Africa -- Eastern Cape Vegetation surveys -- South Africa -- Eastern Cape Land -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4186 , http://hdl.handle.net/10962/d1003754
- Description: Desertification is the diminution or destruction of the biological potential of land, and can lead ultimately to desert-like conditions. The vegetation of southern Africa is claimed to have altered over the past 100 years and much of the change is attributed to pastoral practice. In recent years however there has been much debate around the issue of the deterioration and loss of productivity of the natural rangelands, specifically those under communal management. It is one thing to claim that the vegetation has changed but quite another to produce data and analyses to show this unequivocally. Furthermore it is generally difficult to determine the nature and extent of change in natural ecosystems, as one does not know what the optimal base-line conditions should be. For this reason emphasis has been placed on developing models of potential or expected vegetation. By comparing a model of potential or expected vegetation with that of the contemporary vegetation, areas that deviate from expectation can be identified, in so doing providing evidence of the direction of change in the rangelands under various management treatments. The objective of this study was to determine shifts in the vegetation under different land-use treatments, by developing a technique to predict the potential vegetation of an area. In order to explore the nature and extent of degradation at the landscape scale a study site was selected where a range of land-use and rangeland management practices could be studied in parallel. The mid-Fish River valley consists of three markedly different units of land management, namely commercial rangelands, communal rangelands and nature conservation areas. The vegetation within the mid-Fish River valley falls within the Thicket biome and consists of three main vegetation types namely, Short Succulent Thicket, Medium Succulent Thicket and Mesic Bushclump Savanna. The creation of this potential vegetation model was dependent on the direct gradient analysis approach of relating the community patterns with environmental variables. To achieve this, floristic information was collected at sites along a topographical-moisture gradient. A Canonical Correspondence Analysis (CCA) between the environmental variables and the plant communities produced a classification from which the conditions normally associated with the major plant communities were predicted. When projected as a digital map, the qualifying sites provided a testable hypothesis of the potential vegetation. The results of this study showed a definite grazing gradient, which reflects a change from a more mesic environment towards a more arid environment with an increase in utilisation pressure. The predictive vegetation model proved to be useful for predicting the occurrence of the valley thicket communities within the Eastern Cape.
- Full Text:
- Date Issued: 2001
The weekly newsletter for COSATU - Affiliates and Regions
- COSATU
- Authors: COSATU
- Date: 2001
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/109802 , vital:33191
- Description: The largest nursing organisation in the country, the Democratic Nursing Organisation of South Africa (DENOSA), has taken a historic decision to join COSATU at its recent congress held last week in Pretoria. The 200 delegates at the congress voted in favour of the move. The congress was held between under theme: ’’Nursing facing challenges. Development and HIV/Aids." COSATU campaigns secretary, Mcedisi Nontseie, said the union’s affiliation is a step forward in the consolidation of public sector unions within the federation. "This also consolidates white collar workers within the federation and further demystifies the long held reactionary notion that COSATU only represents workers in the lower ranks,” said Nontseie. South African Football Players Organisation (SAPPU) and Performing Arts Workers Equity (PAWE) joined the federation last year. DONOSA’s affiliation is set to boost the federation’s membership from its present of 1.8 million.
- Full Text:
- Date Issued: 2001
- Authors: COSATU
- Date: 2001
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/109802 , vital:33191
- Description: The largest nursing organisation in the country, the Democratic Nursing Organisation of South Africa (DENOSA), has taken a historic decision to join COSATU at its recent congress held last week in Pretoria. The 200 delegates at the congress voted in favour of the move. The congress was held between under theme: ’’Nursing facing challenges. Development and HIV/Aids." COSATU campaigns secretary, Mcedisi Nontseie, said the union’s affiliation is a step forward in the consolidation of public sector unions within the federation. "This also consolidates white collar workers within the federation and further demystifies the long held reactionary notion that COSATU only represents workers in the lower ranks,” said Nontseie. South African Football Players Organisation (SAPPU) and Performing Arts Workers Equity (PAWE) joined the federation last year. DONOSA’s affiliation is set to boost the federation’s membership from its present of 1.8 million.
- Full Text:
- Date Issued: 2001
Theatre Reviews: Confronting the African nightmate
- Wright, Laurence, Jefferey, C
- Authors: Wright, Laurence , Jefferey, C
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/455890 , vital:75465 , https://hdl.handle.net/10520/AJA1011582X_170
- Description: Yael Farber's adaptation of Julius Caesar marks something of a breakthrough in South African Shakespeare productions. The key achievement is that the play is no longer about Rome or Renaissance England, nor is it about processes of cultural translation or trendy theatrical Africanisation, largely cosmetic. This production is, in a generous way, squarely and pointedly about Africa.
- Full Text:
- Date Issued: 2001
- Authors: Wright, Laurence , Jefferey, C
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/455890 , vital:75465 , https://hdl.handle.net/10520/AJA1011582X_170
- Description: Yael Farber's adaptation of Julius Caesar marks something of a breakthrough in South African Shakespeare productions. The key achievement is that the play is no longer about Rome or Renaissance England, nor is it about processes of cultural translation or trendy theatrical Africanisation, largely cosmetic. This production is, in a generous way, squarely and pointedly about Africa.
- Full Text:
- Date Issued: 2001
Three days to remember in Latin America
- Authors: StreetNet Association
- Date: 2001
- Subjects: StreetNet Association
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/162159 , vital:40767
- Description: What do a street vendor of traditional sweets in Venezuela, an indigenous vendor of flowers in Bolivia and an immigrant vendor of “empanadas” in Costa Rica have in common? A lot despite their different realities! For example, livelihoods that rely on production and sale on the streets or at markets that cost them years of struggle; goods frequently made with their own hands, battles against unsympathetic municipalities; harassment -sometimes violent - from the local police; the desire to organise themselves, which must overcome daily problems of leadership, politics and internal conflicts, and lack of resources to improve their situation or to help solve problems of their fellow vendors.
- Full Text:
- Date Issued: 2001
- Authors: StreetNet Association
- Date: 2001
- Subjects: StreetNet Association
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/162159 , vital:40767
- Description: What do a street vendor of traditional sweets in Venezuela, an indigenous vendor of flowers in Bolivia and an immigrant vendor of “empanadas” in Costa Rica have in common? A lot despite their different realities! For example, livelihoods that rely on production and sale on the streets or at markets that cost them years of struggle; goods frequently made with their own hands, battles against unsympathetic municipalities; harassment -sometimes violent - from the local police; the desire to organise themselves, which must overcome daily problems of leadership, politics and internal conflicts, and lack of resources to improve their situation or to help solve problems of their fellow vendors.
- Full Text:
- Date Issued: 2001
to the setting sun
- Authors: Berold, Robert
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , poem
- Identifier: http://hdl.handle.net/10962/462503 , vital:76309 , ISBN 0028-4459 , https://journals.co.za/doi/epdf/10.10520/AJA00284459_573
- Description: New Coin is one of South Africa's most established and influential poetry journals. It publishes poetry, and poetry-related reviews, commentary and interviews. New Coin places a particular emphasis on evolving forms and experimental use of the English language in poetry in the South African context. In this sense it has traced the most exciting trends and currents in contemporary poetry in South Africa for a decade of more. The journal is published twice a year in June and December by the Institute for the Study of English in Africa (ISEA), Rhodes University.
- Full Text:
- Date Issued: 2001
- Authors: Berold, Robert
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , poem
- Identifier: http://hdl.handle.net/10962/462503 , vital:76309 , ISBN 0028-4459 , https://journals.co.za/doi/epdf/10.10520/AJA00284459_573
- Description: New Coin is one of South Africa's most established and influential poetry journals. It publishes poetry, and poetry-related reviews, commentary and interviews. New Coin places a particular emphasis on evolving forms and experimental use of the English language in poetry in the South African context. In this sense it has traced the most exciting trends and currents in contemporary poetry in South Africa for a decade of more. The journal is published twice a year in June and December by the Institute for the Study of English in Africa (ISEA), Rhodes University.
- Full Text:
- Date Issued: 2001
Tolerance of selected riverine indigenous macroinvertebrates from the Sabie River (Mpumalanga), and Buffalo River (Eastern Cape) to complex saline kraft and textile effluents
- Authors: Zokufa, T S
- Date: 2001
- Subjects: Water quality management -- South Africa -- Sabie River , Water -- South Africa -- Analysis , Water -- Toxicology -- South Africa , Mayflies -- South Africa , Freshwater invertebrates -- South Africa -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5787 , http://hdl.handle.net/10962/d1005475
- Description: Whole Effluent Toxicity (WET) testing has been identified as one of the tools in the management of complex effluents in aquatic ecosystems. In South Africa, toxicity testing has not been required for regulatory purposes. Recently, the Department of Water Affairs and Forestry has adopted WET testing as a tool to evaluate the suitability of hazardous effluent for discharge into receiving environments. This has necessitated suitable procedures to be established for use in the South African situation. With the implementation of the new National Water Act (No 36 of 1998), industries have to comply with set standards to protect the aquatic environment. However, the South African Water Quality Guidelines for Aquatic Ecosystems have been set using international toxicity data, and it is not known if they are comparable with South African conditions. The aim of this study was to investigate the tolerances of selected indigenous riverine invertebrates to complex saline effluents. The study investigated the effects of kraft mill effluent to Tricorythus tinctus, a tricorythid mayfly from the Sabie River, Mpumalanga, and the effects of a textile effluent to baetid mayflies of the Buffalo River, Eastern Cape. Indigenous riverine invertebrates were chosen as test organisms, as there is no toxicity data in South Africa which could be used to evaluate the level of protection afforded by the South African Water Quality Guidelines for Aquatic Ecosystems. The use of indigenous riverine invertebrates added the challenge of variability of a wild population, and the use of a complex effluent as toxicant added the variability of effluent composition. In this study, WET testing was used to determine the dilution of whole effluents required for discharge. Hazard-based guidelines were developed for the disposal of kraft and textile effluents. The level of environmental hazard posed by different effluent concentrations was ranked, and was related to the River Health Class. This indicated effluent concentrations that may be allowed to enter the aquatic environment, e.g. 3% effluent concentration guideline for both general kraft effluent and general textile effluent for the protection of a Class A river. This approach could contribute to the use of an Environmental Risk Assessment, approach for the management of complex effluents. A number of acute 96 hour toxicity tests were conducted following an unreplicated regression design, using kraft and textile effluents as toxicants, mayfly nymphs as test organisms, and river water as diluent and control. Test organisms were sampled from unimpacted, flowing-water riffle areas, and were exposed in recirculating artificial streams (or channels) to a range of effluent concentrations. Mortality was selected as end-point and observed twice daily. The experimental results showed the variability and acute toxicity of both kraft and textile mill effluents. Baetids were more sensitive (mean LC50=16% effluent concentration) to General Textile Effluent (GTE), but less sensitive to Post Irrigation Textile Effluent (PITE). Textile effluent (PITE) held in a holding dam were therefore less variable and less toxic; suggesting that stabilization of the effluent could have contributed to reduced toxicity. Effluent composition, e.g. higher calcium levels, may also have contributed to lowering toxicity. T. tinctus was sensitive to kraft effluents, but showed less variable responses to Irrigation Kraft Effluent than General Kraft Effluent. Toxicity test data indicated that GKE, IKE and GTE should not enter the aquatic environment without treatment, as they can cause adverse effects to aquatic biota. Both kraft and textile effluents must therefore be treated before discharge. Different responses to different effluent batches were probably due to effluent variability. The use of indigenous organisms, and not a standard laboratory organism, could also have contributed to variability. A hazard-based approach could be useful, as it will provide a consistent basis for deciding on the acceptability of impacts, while allowing natural site-specific differences to be taken into account.
- Full Text:
- Date Issued: 2001
- Authors: Zokufa, T S
- Date: 2001
- Subjects: Water quality management -- South Africa -- Sabie River , Water -- South Africa -- Analysis , Water -- Toxicology -- South Africa , Mayflies -- South Africa , Freshwater invertebrates -- South Africa -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5787 , http://hdl.handle.net/10962/d1005475
- Description: Whole Effluent Toxicity (WET) testing has been identified as one of the tools in the management of complex effluents in aquatic ecosystems. In South Africa, toxicity testing has not been required for regulatory purposes. Recently, the Department of Water Affairs and Forestry has adopted WET testing as a tool to evaluate the suitability of hazardous effluent for discharge into receiving environments. This has necessitated suitable procedures to be established for use in the South African situation. With the implementation of the new National Water Act (No 36 of 1998), industries have to comply with set standards to protect the aquatic environment. However, the South African Water Quality Guidelines for Aquatic Ecosystems have been set using international toxicity data, and it is not known if they are comparable with South African conditions. The aim of this study was to investigate the tolerances of selected indigenous riverine invertebrates to complex saline effluents. The study investigated the effects of kraft mill effluent to Tricorythus tinctus, a tricorythid mayfly from the Sabie River, Mpumalanga, and the effects of a textile effluent to baetid mayflies of the Buffalo River, Eastern Cape. Indigenous riverine invertebrates were chosen as test organisms, as there is no toxicity data in South Africa which could be used to evaluate the level of protection afforded by the South African Water Quality Guidelines for Aquatic Ecosystems. The use of indigenous riverine invertebrates added the challenge of variability of a wild population, and the use of a complex effluent as toxicant added the variability of effluent composition. In this study, WET testing was used to determine the dilution of whole effluents required for discharge. Hazard-based guidelines were developed for the disposal of kraft and textile effluents. The level of environmental hazard posed by different effluent concentrations was ranked, and was related to the River Health Class. This indicated effluent concentrations that may be allowed to enter the aquatic environment, e.g. 3% effluent concentration guideline for both general kraft effluent and general textile effluent for the protection of a Class A river. This approach could contribute to the use of an Environmental Risk Assessment, approach for the management of complex effluents. A number of acute 96 hour toxicity tests were conducted following an unreplicated regression design, using kraft and textile effluents as toxicants, mayfly nymphs as test organisms, and river water as diluent and control. Test organisms were sampled from unimpacted, flowing-water riffle areas, and were exposed in recirculating artificial streams (or channels) to a range of effluent concentrations. Mortality was selected as end-point and observed twice daily. The experimental results showed the variability and acute toxicity of both kraft and textile mill effluents. Baetids were more sensitive (mean LC50=16% effluent concentration) to General Textile Effluent (GTE), but less sensitive to Post Irrigation Textile Effluent (PITE). Textile effluent (PITE) held in a holding dam were therefore less variable and less toxic; suggesting that stabilization of the effluent could have contributed to reduced toxicity. Effluent composition, e.g. higher calcium levels, may also have contributed to lowering toxicity. T. tinctus was sensitive to kraft effluents, but showed less variable responses to Irrigation Kraft Effluent than General Kraft Effluent. Toxicity test data indicated that GKE, IKE and GTE should not enter the aquatic environment without treatment, as they can cause adverse effects to aquatic biota. Both kraft and textile effluents must therefore be treated before discharge. Different responses to different effluent batches were probably due to effluent variability. The use of indigenous organisms, and not a standard laboratory organism, could also have contributed to variability. A hazard-based approach could be useful, as it will provide a consistent basis for deciding on the acceptability of impacts, while allowing natural site-specific differences to be taken into account.
- Full Text:
- Date Issued: 2001
Towards a broader application of decision-making paradigms: a case study of the establishment of ECOWAS Cease-fire Monitoring Group (ECOMOG)
- Authors: Domson-Lindsay, Albert
- Date: 2001
- Subjects: Liberia -- History -- Civil War, 1989-1996 , Liberia -- politics and government -- 1980- , Ecomog , Economic community of west african states
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2771 , http://hdl.handle.net/10962/d1002981 , Liberia -- History -- Civil War, 1989-1996 , Liberia -- politics and government -- 1980- , Ecomog , Economic community of west african states
- Description: The thesis in the main, looks at the decision-making process which underlined the Economic Community of West African States' attempt to end the Liberian crisis. It examines the establishment of ECOMOG to intervene in the Liberian civil crisis and the various pacific attempts to resolve the Liberian question. It does so through the medium of decision - making theory and some of the conceptual models that have flowed out of it. The thesis' focus on the decisional process of a regional body marks an attempt to broaden the scope of application of decision - making paradigms, which are usually employed to analyse decisions of national governments. The imperative for analysing the decisional process of ECOWAS in its quest to find solution to the Liberian problem has in part been dictated by the novelty of the ECOMOG concept. It marks the first major attempt of a sub - regional economic organization to successfully find solution to a civil conflict, as a result, there are numerous lessons to be gleaned from its failures and successes. Its relevance in the African context, with its intractable conflicts cannot be overemphasized. It has also been motivated by the fact that more works need to be produced on the decision-making processes of governments and regional bodies within the continent. The thesis argues that, both rational and "irrational" elements infused the decisional process of ECOW AS in its bid to solve the Liberian Crisis. Among other things, Policy-makers were influenced in their choice of decision by rational calculations based on national interest. It examines the clash of interests which characterized the establishment ofECOMOG as an tntervention force, the impasse this fostered and how it was eventually resolved. It postulates that exteljIlal actors influenced the decision process and that policy :Qiakers were aided to make the decisions they made by other organs in the decisional chain. The "irrational" component of the process, among other things, could be seen from the fact that the Liberian question was solved in " bits and pieces". Besides, blunders were committed through defective decision - making mechanism. The thesis concludes by offering suggestions to improve the quality of ECOW AS decision-making process with regard to conflict resolution and how to achieve regional consensus.
- Full Text:
- Date Issued: 2001
- Authors: Domson-Lindsay, Albert
- Date: 2001
- Subjects: Liberia -- History -- Civil War, 1989-1996 , Liberia -- politics and government -- 1980- , Ecomog , Economic community of west african states
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2771 , http://hdl.handle.net/10962/d1002981 , Liberia -- History -- Civil War, 1989-1996 , Liberia -- politics and government -- 1980- , Ecomog , Economic community of west african states
- Description: The thesis in the main, looks at the decision-making process which underlined the Economic Community of West African States' attempt to end the Liberian crisis. It examines the establishment of ECOMOG to intervene in the Liberian civil crisis and the various pacific attempts to resolve the Liberian question. It does so through the medium of decision - making theory and some of the conceptual models that have flowed out of it. The thesis' focus on the decisional process of a regional body marks an attempt to broaden the scope of application of decision - making paradigms, which are usually employed to analyse decisions of national governments. The imperative for analysing the decisional process of ECOWAS in its quest to find solution to the Liberian problem has in part been dictated by the novelty of the ECOMOG concept. It marks the first major attempt of a sub - regional economic organization to successfully find solution to a civil conflict, as a result, there are numerous lessons to be gleaned from its failures and successes. Its relevance in the African context, with its intractable conflicts cannot be overemphasized. It has also been motivated by the fact that more works need to be produced on the decision-making processes of governments and regional bodies within the continent. The thesis argues that, both rational and "irrational" elements infused the decisional process of ECOW AS in its bid to solve the Liberian Crisis. Among other things, Policy-makers were influenced in their choice of decision by rational calculations based on national interest. It examines the clash of interests which characterized the establishment ofECOMOG as an tntervention force, the impasse this fostered and how it was eventually resolved. It postulates that exteljIlal actors influenced the decision process and that policy :Qiakers were aided to make the decisions they made by other organs in the decisional chain. The "irrational" component of the process, among other things, could be seen from the fact that the Liberian question was solved in " bits and pieces". Besides, blunders were committed through defective decision - making mechanism. The thesis concludes by offering suggestions to improve the quality of ECOW AS decision-making process with regard to conflict resolution and how to achieve regional consensus.
- Full Text:
- Date Issued: 2001
Towards a collaborative approach to teacher professional development : a journey of negotiation
- Authors: Southwood, Sue
- Date: 2001
- Subjects: Teachers -- Training of -- South Africa Teachers -- In-service training -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1866 , http://hdl.handle.net/10962/d1004649
- Description: The research presented in this thesis is a case study, based on ethnographic principles, located in the interpretive paradigm of qualitative research. The focus is specifically on the development of a collaborative approach ro teacher professional development: an approach that recognises and celebrates teachers themselves as resources for their own and other teachers' professional development. The study was carried out over a period of four years with a group of twelve teachers who had recognised the need and expressed the desire to develop their teaching. The research evolved in two main phases. The initial phase was based on the implementation and evaluation of a project designed to encourage a collaborative approach to teacher development based on mutual peer support. This led to a second phase, the main focus of the research, aimed at gaining a greater understanding of the teachers' situation and situating their practice in the wider context generated by this understanding. Conversations with the teachers led to the identification of dimensions and tensions characterising their experience. The research presented here, represents an attempt to understand, interpret and make recommendations relating to the professional development of teachers. The understanding is linked to the teachers' educational biographies and experience of the culture in which they are situated. The interpretation is based on what may be viewed as a dynamic ongoing construction of meaning - a journey of negotiation. The text, described as a narrative collage, a tapestry of voices interwoven by threads of negotiation, represents a collaborative accomplishment. The teachers' words have been interpretively framed and these constructions validated in an interpersonal construction of social reality. The reader is invited to engage in an act of complicity, to collude with the text in the construction and negotiation of shared meaning, possibly finding resonance with their own situations. Reflections on the teachers' experience reveal journeys which resonate with that of the society in which the school is located - 'a case in transition' - situated between an environment characterised by constrained cooperation and an environment characterised by freer collaboration. The overall tension may be viewed metaphorically as a 'Tug o' War'. On one end of the rope is a cultural legacy of authority, isolation, social division and conservatism, while on the other end there is a pull towards greater autonomy and interaction, to adapt rather than conserve and to work together in mutual collegial support: a struggle between cooperating with what is and collaborating towards what could be. The main contention of this thesis is that we ought strongly to support and encourage collaborative approaches to professional development based on mutual peer support. We need to look towards a future of open professionalism where the teachers are regarded as key persons in the process. The attainment of such an ideal needs to be seen as part of systemic changes in management, policies and structure geared towards greater inclusivity and democratic practice; it necessitates a coherent approach that is based on relationships of mutual respect and appreciation.
- Full Text:
- Date Issued: 2001
- Authors: Southwood, Sue
- Date: 2001
- Subjects: Teachers -- Training of -- South Africa Teachers -- In-service training -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1866 , http://hdl.handle.net/10962/d1004649
- Description: The research presented in this thesis is a case study, based on ethnographic principles, located in the interpretive paradigm of qualitative research. The focus is specifically on the development of a collaborative approach ro teacher professional development: an approach that recognises and celebrates teachers themselves as resources for their own and other teachers' professional development. The study was carried out over a period of four years with a group of twelve teachers who had recognised the need and expressed the desire to develop their teaching. The research evolved in two main phases. The initial phase was based on the implementation and evaluation of a project designed to encourage a collaborative approach to teacher development based on mutual peer support. This led to a second phase, the main focus of the research, aimed at gaining a greater understanding of the teachers' situation and situating their practice in the wider context generated by this understanding. Conversations with the teachers led to the identification of dimensions and tensions characterising their experience. The research presented here, represents an attempt to understand, interpret and make recommendations relating to the professional development of teachers. The understanding is linked to the teachers' educational biographies and experience of the culture in which they are situated. The interpretation is based on what may be viewed as a dynamic ongoing construction of meaning - a journey of negotiation. The text, described as a narrative collage, a tapestry of voices interwoven by threads of negotiation, represents a collaborative accomplishment. The teachers' words have been interpretively framed and these constructions validated in an interpersonal construction of social reality. The reader is invited to engage in an act of complicity, to collude with the text in the construction and negotiation of shared meaning, possibly finding resonance with their own situations. Reflections on the teachers' experience reveal journeys which resonate with that of the society in which the school is located - 'a case in transition' - situated between an environment characterised by constrained cooperation and an environment characterised by freer collaboration. The overall tension may be viewed metaphorically as a 'Tug o' War'. On one end of the rope is a cultural legacy of authority, isolation, social division and conservatism, while on the other end there is a pull towards greater autonomy and interaction, to adapt rather than conserve and to work together in mutual collegial support: a struggle between cooperating with what is and collaborating towards what could be. The main contention of this thesis is that we ought strongly to support and encourage collaborative approaches to professional development based on mutual peer support. We need to look towards a future of open professionalism where the teachers are regarded as key persons in the process. The attainment of such an ideal needs to be seen as part of systemic changes in management, policies and structure geared towards greater inclusivity and democratic practice; it necessitates a coherent approach that is based on relationships of mutual respect and appreciation.
- Full Text:
- Date Issued: 2001
Towards more accurate measurement of the value of the arts to society: economic impact and willingness to pay studies at the Standard Bank National Arts Festival
- Authors: Snowball, Jeanette Dalziel
- Date: 2001
- Subjects: Standard Bank National Arts Festival , Standard Bank National Arts Festival -- Economic aspects , Art -- Economic aspects , Money in art , Art -- Marketing , Performing arts festivals -- Economic aspects -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:939 , http://hdl.handle.net/10962/d1002672
- Description: The accurate measurement of the value of the arts to society is becoming increasingly important in developing countries, like South Africa, where the arts must compete with housing, health, education and the like for public funds. Motivation for the public funding of arts events, like the Standard Bank National Arts Festival in Grahamstown, is usually based on the economic impact, that is, the financial benefits to the region, of such events. The argument is problematic, however, because the primary recipients of such economic benefits are often middle to upper income groups who also attend more arts performances. Furthermore, the studies have not taken into account the positive externalities which, it is argued, are generated by the arts and are enjoyed by attenders and non attenders alike. This thesis argues that it is the social benefits which the arts provide, those external to the market, which should be the basis of public funding. In order to quantify these positive externalities, a willingness to pay (WTP) study was conducted in the Grahamstown region. It is generally, but erroneously, believed that the Festival does not benefit the poorer, largely black, Grahamstown East residents. The study found that, in addition to the economic value (R23 - 25 million a year), the non-market benefits which the festival provides are worth between R2.3 and R3 million a year and form a very important part of its value, particularly to low income groups. The study also found that there are methodological adjustments which can be made to WTP studies to successfully control for the many forms of bias it is prone to. By using a combination of closed and open ended and liable and non-liable questions, the motivation of respondents' answers to WTP questions was determined, making it possible to adjust for bias caused by, for example, "free rider" and "warm glow" responses. It is argued that by identifying and excluding such responses from WTP surveys, it is possible to reduce bias to an acceptable level.
- Full Text:
- Date Issued: 2001
- Authors: Snowball, Jeanette Dalziel
- Date: 2001
- Subjects: Standard Bank National Arts Festival , Standard Bank National Arts Festival -- Economic aspects , Art -- Economic aspects , Money in art , Art -- Marketing , Performing arts festivals -- Economic aspects -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:939 , http://hdl.handle.net/10962/d1002672
- Description: The accurate measurement of the value of the arts to society is becoming increasingly important in developing countries, like South Africa, where the arts must compete with housing, health, education and the like for public funds. Motivation for the public funding of arts events, like the Standard Bank National Arts Festival in Grahamstown, is usually based on the economic impact, that is, the financial benefits to the region, of such events. The argument is problematic, however, because the primary recipients of such economic benefits are often middle to upper income groups who also attend more arts performances. Furthermore, the studies have not taken into account the positive externalities which, it is argued, are generated by the arts and are enjoyed by attenders and non attenders alike. This thesis argues that it is the social benefits which the arts provide, those external to the market, which should be the basis of public funding. In order to quantify these positive externalities, a willingness to pay (WTP) study was conducted in the Grahamstown region. It is generally, but erroneously, believed that the Festival does not benefit the poorer, largely black, Grahamstown East residents. The study found that, in addition to the economic value (R23 - 25 million a year), the non-market benefits which the festival provides are worth between R2.3 and R3 million a year and form a very important part of its value, particularly to low income groups. The study also found that there are methodological adjustments which can be made to WTP studies to successfully control for the many forms of bias it is prone to. By using a combination of closed and open ended and liable and non-liable questions, the motivation of respondents' answers to WTP questions was determined, making it possible to adjust for bias caused by, for example, "free rider" and "warm glow" responses. It is argued that by identifying and excluding such responses from WTP surveys, it is possible to reduce bias to an acceptable level.
- Full Text:
- Date Issued: 2001
Traditional veterinary medicine in the Alice district of the Eastern Cape Province, South Africa
- Dold, Anthony P, Cocks, Michelle L
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6513 , http://hdl.handle.net/10962/d1005941
- Description: Resource-poor farmers in rural and peri-urban areas have limited access to veterinary care in terms of support services (from state and private veterinarian and animal health technicians), information about the prevention and treatment of livestock diseases, and preventative and therapeutic veterinary medicines. This results in reduced productivity and in livestock disease and deaths, which is a great burden on these farmers, who can least afford the loss of their animals. There is a need to encourage disadvantaged farmers to use available resources and methods, at minimal cost, and to improve their productivity. One of these resources is ethnoveterinary medicine. A list of 53 plants used as veterinary medicines by stock farmers in the Alice district in the Eastern Cape is presented together with their preparation and methods of administration.
- Full Text:
- Date Issued: 2001
- Authors: Dold, Anthony P , Cocks, Michelle L
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6513 , http://hdl.handle.net/10962/d1005941
- Description: Resource-poor farmers in rural and peri-urban areas have limited access to veterinary care in terms of support services (from state and private veterinarian and animal health technicians), information about the prevention and treatment of livestock diseases, and preventative and therapeutic veterinary medicines. This results in reduced productivity and in livestock disease and deaths, which is a great burden on these farmers, who can least afford the loss of their animals. There is a need to encourage disadvantaged farmers to use available resources and methods, at minimal cost, and to improve their productivity. One of these resources is ethnoveterinary medicine. A list of 53 plants used as veterinary medicines by stock farmers in the Alice district in the Eastern Cape is presented together with their preparation and methods of administration.
- Full Text:
- Date Issued: 2001
Trends in mobilisation and unionisation in South Africa and Germany: a comparative analysis
- Authors: Whiteley, Julianne Beverley
- Date: 2001
- Subjects: Industrial mobilization -- South Africa , Labor unions -- South Africa , Industrial mobilization -- Germany , Labor unions -- Germany , South Africa -- Economic conditions , Germany -- Economic conditions
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3332 , http://hdl.handle.net/10962/d1003125 , Industrial mobilization -- South Africa , Labor unions -- South Africa , Industrial mobilization -- Germany , Labor unions -- Germany , South Africa -- Economic conditions , Germany -- Economic conditions
- Description: The purpose of this study is to investigate long-term trends in the union membership of South Africa and Germany, and to highlight trends in unionisation in both of these countries over a period of time. The long-term aspect of this study differentiates it from more detailed specific studies concerned with the individual fortunes of confederations or unions. The changing fortunes of trade unions have been associated with changes in work organisation, the influence of institutional pressures, or long term changes in the economic cycle. All these factors may, of course, shape and be shaped by each other. From a comparative perspective this dissertation determines whether the fortunes of unions are ultimately a product of the long waves of an economic cycle, or if other factors, such as variations in union/state relations, changes in the forms of work organisation and shifts in the employment market, impact upon union membership and mobilisation. It is hoped that the comparison of a transitional and an advanced economy may shed new light on the causes of union growth and decline, and the impact of specific social, legal and cultural variables thereon. The theoretical frame of reference for this study emerged from literature pertaining to union growth and decline. This literature discusses the historical, economic and sectoral challenges that confront the identity of unions and their ability to mobilise membership within contemporary labour markets. The entire study relies heavily on primary data collected from a wide range of sources in both countries. This method facilitates the comparison and cross-checking of information, which ensures a full and balanced study. A synthesis of the facts obtained led to certain suggestions relating to the areas in which both South African and German labour organisations could adapt their agenda and interests to the changing nature of the employment market in order to avert membership decline. The methodology of this research draws from Skopol’s work which argues that social studies ought to be grounded in historical experience in order to make sense out of specific social events that occur today. The research design utilises an initial comparative historical-political analysis of the emergence of unionism in South Africa and Germany, so as to establish those factors which have, in the past, affected union growth and decline in both countries. Thereafter, the impact of contemporary economic and sectoral trends that reoccur in the South African and German labour markets are examined and compared, in order to establish their influence on the growth or decline of union membership in both countries in the future. This study consists of four sections. The first section comprises a historical dimension that uses Valenzuela’s work relating to the political nature of labour movements to establish those factors which, in the past, have affected union growth and decline. This is done to determine whether the type of insertion of labour movements into historical national political processes, and the links formed between trade unions and political parties influences membership growth or decline. The following three sections deal with the present challenges that may affect the unions in the future. Section Two deals with factors of economic recession (namely, poverty and unemployment) which confront trade unions in the 1990s. Hyman’s Theory of Disaggregation is applied to determine if recessive socio-economic factors can account for the strength of decline of unions, as opposed to union mobilisation being purely linked to transitions between long waves of the economy as Kelly suggests. The relevance of these theories to the rise and decline of unionism in South Africa and Germany is compared and contrasted. The third section determines whether changes to more flexible forms of work organisation and shifts in the employment market can account for the contrasting strength of the South African labour movement and the decline of the German labour movement today. The way in which these issues impact negatively upon union strength in South Africa and Germany in the 1990s is compared and contrasted, again using Hyman’s Theory of Disaggregation. The final section establishes whether or not the roles adopted by the South African and German labour movements during their confrontation with labour repressive regimes impacts upon their ability to attract union membership today, despite the constraints imposed upon unions by prevailing economic and structural uncertainties. Therefore the historicity of the South African and German labour movements, (based upon the findings of the first part of this study), is referred back to. At the same time, the reactions of the South African and German labour movements to prevailing economic and structural realities, (as examined in the second part of this research) are re-examined. Three conclusions are reached. Firstly, regardless of their strengths or weaknesses, all labour organisations are capable of adjusting to the adverse changes taking place in contemporary employment markets if they prove willing to advance and defend the interests of all who work, including those in the informal sector. If unions continue to neglect the informal labour market, they run the risk of being transposed by social movements that are antagonistic to trade unions or new expressions of the workforce’s latent collectivism. Secondly, in successfully playing a social movement role that led to the downfall of Apartheid in 1994, the South African labour movement has evolved as an energetic body with a dimension of recumbent militancy that attempts to adapt its identity to the changing nature of the employment market. This enables the South African labour movement to continue to attract membership despite the prevailing economic uncertainties. In contrast, forced co-operation and consensus within the German industrial relations arena since World War Two has resulted in a less dynamic union movement that lacks initiative in adapting to the changing nature of the employment market. The result is a decline in unionism. Finally, the fortunes of unions are not, as Kelly suggests, purely a product of economic cycles. Political climates can also influence mobilisation, as has occurred in both South Africa and Germany. This implies that mobilisation is not only activated by the economic dissatisfaction of a union movement.
- Full Text:
- Date Issued: 2001
- Authors: Whiteley, Julianne Beverley
- Date: 2001
- Subjects: Industrial mobilization -- South Africa , Labor unions -- South Africa , Industrial mobilization -- Germany , Labor unions -- Germany , South Africa -- Economic conditions , Germany -- Economic conditions
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3332 , http://hdl.handle.net/10962/d1003125 , Industrial mobilization -- South Africa , Labor unions -- South Africa , Industrial mobilization -- Germany , Labor unions -- Germany , South Africa -- Economic conditions , Germany -- Economic conditions
- Description: The purpose of this study is to investigate long-term trends in the union membership of South Africa and Germany, and to highlight trends in unionisation in both of these countries over a period of time. The long-term aspect of this study differentiates it from more detailed specific studies concerned with the individual fortunes of confederations or unions. The changing fortunes of trade unions have been associated with changes in work organisation, the influence of institutional pressures, or long term changes in the economic cycle. All these factors may, of course, shape and be shaped by each other. From a comparative perspective this dissertation determines whether the fortunes of unions are ultimately a product of the long waves of an economic cycle, or if other factors, such as variations in union/state relations, changes in the forms of work organisation and shifts in the employment market, impact upon union membership and mobilisation. It is hoped that the comparison of a transitional and an advanced economy may shed new light on the causes of union growth and decline, and the impact of specific social, legal and cultural variables thereon. The theoretical frame of reference for this study emerged from literature pertaining to union growth and decline. This literature discusses the historical, economic and sectoral challenges that confront the identity of unions and their ability to mobilise membership within contemporary labour markets. The entire study relies heavily on primary data collected from a wide range of sources in both countries. This method facilitates the comparison and cross-checking of information, which ensures a full and balanced study. A synthesis of the facts obtained led to certain suggestions relating to the areas in which both South African and German labour organisations could adapt their agenda and interests to the changing nature of the employment market in order to avert membership decline. The methodology of this research draws from Skopol’s work which argues that social studies ought to be grounded in historical experience in order to make sense out of specific social events that occur today. The research design utilises an initial comparative historical-political analysis of the emergence of unionism in South Africa and Germany, so as to establish those factors which have, in the past, affected union growth and decline in both countries. Thereafter, the impact of contemporary economic and sectoral trends that reoccur in the South African and German labour markets are examined and compared, in order to establish their influence on the growth or decline of union membership in both countries in the future. This study consists of four sections. The first section comprises a historical dimension that uses Valenzuela’s work relating to the political nature of labour movements to establish those factors which, in the past, have affected union growth and decline. This is done to determine whether the type of insertion of labour movements into historical national political processes, and the links formed between trade unions and political parties influences membership growth or decline. The following three sections deal with the present challenges that may affect the unions in the future. Section Two deals with factors of economic recession (namely, poverty and unemployment) which confront trade unions in the 1990s. Hyman’s Theory of Disaggregation is applied to determine if recessive socio-economic factors can account for the strength of decline of unions, as opposed to union mobilisation being purely linked to transitions between long waves of the economy as Kelly suggests. The relevance of these theories to the rise and decline of unionism in South Africa and Germany is compared and contrasted. The third section determines whether changes to more flexible forms of work organisation and shifts in the employment market can account for the contrasting strength of the South African labour movement and the decline of the German labour movement today. The way in which these issues impact negatively upon union strength in South Africa and Germany in the 1990s is compared and contrasted, again using Hyman’s Theory of Disaggregation. The final section establishes whether or not the roles adopted by the South African and German labour movements during their confrontation with labour repressive regimes impacts upon their ability to attract union membership today, despite the constraints imposed upon unions by prevailing economic and structural uncertainties. Therefore the historicity of the South African and German labour movements, (based upon the findings of the first part of this study), is referred back to. At the same time, the reactions of the South African and German labour movements to prevailing economic and structural realities, (as examined in the second part of this research) are re-examined. Three conclusions are reached. Firstly, regardless of their strengths or weaknesses, all labour organisations are capable of adjusting to the adverse changes taking place in contemporary employment markets if they prove willing to advance and defend the interests of all who work, including those in the informal sector. If unions continue to neglect the informal labour market, they run the risk of being transposed by social movements that are antagonistic to trade unions or new expressions of the workforce’s latent collectivism. Secondly, in successfully playing a social movement role that led to the downfall of Apartheid in 1994, the South African labour movement has evolved as an energetic body with a dimension of recumbent militancy that attempts to adapt its identity to the changing nature of the employment market. This enables the South African labour movement to continue to attract membership despite the prevailing economic uncertainties. In contrast, forced co-operation and consensus within the German industrial relations arena since World War Two has resulted in a less dynamic union movement that lacks initiative in adapting to the changing nature of the employment market. The result is a decline in unionism. Finally, the fortunes of unions are not, as Kelly suggests, purely a product of economic cycles. Political climates can also influence mobilisation, as has occurred in both South Africa and Germany. This implies that mobilisation is not only activated by the economic dissatisfaction of a union movement.
- Full Text:
- Date Issued: 2001
Using gene shuffling to increase genetic diversity in genes involved in beta-lactam biosynthesis
- Authors: Tarr, Shahida
- Date: 2001
- Subjects: Beta lactam antibiotics , Genes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4014 , http://hdl.handle.net/10962/d1004074 , Beta lactam antibiotics , Genes
- Description: The actinomycetes are gram-positive bacteria that produce more than two-thirds of the known biologically active microbial natural products, including many commercially important antibiotics, anti-cancer agents, other pharmacologically useful agents, animal health products and agrochemicals. The prevailing utilization of antibiotics continues to be the mainstay against microbial infections and a majority ofthe over six thousand antibiotics discovered thus far are from Streptomyces spp. One of the most well-characterized antibiotic biosynthetic pathway is the one involving the biosynthesis of the penicillins, cephalosporins and cephamycins. This pathway involves two initial steps which are common in filamentous fungi, lower eukaryotes and prokaryotes. The penam nucleus of penicillins and the cephem nucleus of both cephamycins andcephalosporins are formed by the condensation of the three precursor amino acids L-a-aminoadipic acid, Lcysteine and L-valine by a mechanism designated as 'non-ribosomal peptide synthesis', which involves activation and condensation of the three component amino acids and epimerization of the L- to D-valine to form a linear acyclic tripeptide called o-(L-a-aminoadipyl)-L-cysteinyl-Dvaline (ACV) by the action of a peptide synthetase. ACV is then cyclized to form isopenicillin N, an intermediate that contains an L-a-aminoadipyl side-chain attached to the penem nucleus (Fig. 1.2) by isopenicilin N synthase (IPNS or Cyclase) and this encompasses the creation of the Beta-lactam and thiazolidine rings. A broad range of ~-lactam producing Streptomyces spp were grown, the DNA extraction procedure optimised and total chromosomal DNA isolated. A bioinformatics analysis of known IPNS gene sequences allowed the synthesis of PCR primers for the iso-penicillin N synthase gene. IPNS genes and lPNS-like genes were successfully amplified from the total DNA of ten strains including two novel thermophilic strains, A. and B. Sequencing was carried out on the genes from S. hygroscopicus, S. tanashiensis and the two thermophiles A and B. This allowed development of the conditions for gene shuffiing of the IPNS gene which was carried out pairwise and resulted in the reconstitution of shuffied genes of the correct size. The resulting mixed gene sequences were cloned into the pTrcHis2-TOPO expression vector and the plasmid DNA screened and assayed for IPNS activity using HPLC which showed ten fold increase in IPNS activity as a result of the shuffiing.
- Full Text:
- Date Issued: 2001
- Authors: Tarr, Shahida
- Date: 2001
- Subjects: Beta lactam antibiotics , Genes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4014 , http://hdl.handle.net/10962/d1004074 , Beta lactam antibiotics , Genes
- Description: The actinomycetes are gram-positive bacteria that produce more than two-thirds of the known biologically active microbial natural products, including many commercially important antibiotics, anti-cancer agents, other pharmacologically useful agents, animal health products and agrochemicals. The prevailing utilization of antibiotics continues to be the mainstay against microbial infections and a majority ofthe over six thousand antibiotics discovered thus far are from Streptomyces spp. One of the most well-characterized antibiotic biosynthetic pathway is the one involving the biosynthesis of the penicillins, cephalosporins and cephamycins. This pathway involves two initial steps which are common in filamentous fungi, lower eukaryotes and prokaryotes. The penam nucleus of penicillins and the cephem nucleus of both cephamycins andcephalosporins are formed by the condensation of the three precursor amino acids L-a-aminoadipic acid, Lcysteine and L-valine by a mechanism designated as 'non-ribosomal peptide synthesis', which involves activation and condensation of the three component amino acids and epimerization of the L- to D-valine to form a linear acyclic tripeptide called o-(L-a-aminoadipyl)-L-cysteinyl-Dvaline (ACV) by the action of a peptide synthetase. ACV is then cyclized to form isopenicillin N, an intermediate that contains an L-a-aminoadipyl side-chain attached to the penem nucleus (Fig. 1.2) by isopenicilin N synthase (IPNS or Cyclase) and this encompasses the creation of the Beta-lactam and thiazolidine rings. A broad range of ~-lactam producing Streptomyces spp were grown, the DNA extraction procedure optimised and total chromosomal DNA isolated. A bioinformatics analysis of known IPNS gene sequences allowed the synthesis of PCR primers for the iso-penicillin N synthase gene. IPNS genes and lPNS-like genes were successfully amplified from the total DNA of ten strains including two novel thermophilic strains, A. and B. Sequencing was carried out on the genes from S. hygroscopicus, S. tanashiensis and the two thermophiles A and B. This allowed development of the conditions for gene shuffiing of the IPNS gene which was carried out pairwise and resulted in the reconstitution of shuffied genes of the correct size. The resulting mixed gene sequences were cloned into the pTrcHis2-TOPO expression vector and the plasmid DNA screened and assayed for IPNS activity using HPLC which showed ten fold increase in IPNS activity as a result of the shuffiing.
- Full Text:
- Date Issued: 2001
Using virtual reality to monitor and control an industrial robot via the Internet
- Authors: Vermeulen, Heinrich
- Date: 2001
- Subjects: Virtual reality , Robotics -- Computer programs
- Language: English
- Type: Thesis , Masters , MTech (Engineering)
- Identifier: vital:10820 , http://hdl.handle.net/10948/74 , Virtual reality , Robotics -- Computer programs
- Description: Manufacturing processes may be modeled in various ways, including 3D modeling. There is a need to visualise, control and monitor manufacturing processes remotely via the Internet. Virtual Reality (VR) can be described as the science of integrating man with information. It is based on three distinct environments: three-dimensional, interactive and computer-generated. VR has come to the Internet in the form of VR modeling. The evolution of Web technologies in recent years has enabled the use of VR modeling for visualisation of manufacturing processes. The VR modeling language (VRML), which has become the standard for transmitting 3D virtual worlds across the Internet, can be used to control and monitor manufacturing processes visually. A 3D model of a manufacturing process, specifically an industrial robot arm, was created for this project. This model was successfully linked to the industrial robot that it represents in order to control and monitor the robot’s actions remotely via the Internet using Web technologies. This dissertation proves the viablity of using Virtual Reality to effectively visualise, monitor and control an industrial robot via the Internet. It also describes the methodology that was followed in modeling the industrial robot arm in VRML as well as linking the model to the real world application.
- Full Text:
- Date Issued: 2001
- Authors: Vermeulen, Heinrich
- Date: 2001
- Subjects: Virtual reality , Robotics -- Computer programs
- Language: English
- Type: Thesis , Masters , MTech (Engineering)
- Identifier: vital:10820 , http://hdl.handle.net/10948/74 , Virtual reality , Robotics -- Computer programs
- Description: Manufacturing processes may be modeled in various ways, including 3D modeling. There is a need to visualise, control and monitor manufacturing processes remotely via the Internet. Virtual Reality (VR) can be described as the science of integrating man with information. It is based on three distinct environments: three-dimensional, interactive and computer-generated. VR has come to the Internet in the form of VR modeling. The evolution of Web technologies in recent years has enabled the use of VR modeling for visualisation of manufacturing processes. The VR modeling language (VRML), which has become the standard for transmitting 3D virtual worlds across the Internet, can be used to control and monitor manufacturing processes visually. A 3D model of a manufacturing process, specifically an industrial robot arm, was created for this project. This model was successfully linked to the industrial robot that it represents in order to control and monitor the robot’s actions remotely via the Internet using Web technologies. This dissertation proves the viablity of using Virtual Reality to effectively visualise, monitor and control an industrial robot via the Internet. It also describes the methodology that was followed in modeling the industrial robot arm in VRML as well as linking the model to the real world application.
- Full Text:
- Date Issued: 2001
Valuing South Africa's savannas: Methodological Issues
- Ballance, A, Shackleton, Charlie M, Shackleton, Sheona E, Geach, B S, Crookes, D, De Wit, M, Evans, J, von Maltitz, Graham P, Willis, C B, Kelatwang, S, Havemann, J
- Authors: Ballance, A , Shackleton, Charlie M , Shackleton, Sheona E , Geach, B S , Crookes, D , De Wit, M , Evans, J , von Maltitz, Graham P , Willis, C B , Kelatwang, S , Havemann, J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182262 , vital:43816 , xlink:href="https://hdl.handle.net/10520/EJC33860"
- Description: Natural resource valuation techniques have been applied in recent years to savannas and savanna resources in South and southern Africa. Results from these studies have been used to demonstrate the importance of savannas, and to assist in resource-use planning. Because these studies have been conducted to meet different research objectives a large number of disparities exist between studies. This makes comparison of results difficult and identification of underlying drivers of value is problematic. This paper discusses issues which can lead to differences in estimates of resource value, and makes recommendations for future studies to reduce incompatibilities. In particular, this paper recommends that future studies make full descriptions of the objectives of the study, the background characteristics of the study area (including the social, political, economic, cultural, and biophysical characteristics), the methods used, and assumptions made. In this way, the values reported from case studies may be used in other research and decision-making exercises.
- Full Text:
- Date Issued: 2001
- Authors: Ballance, A , Shackleton, Charlie M , Shackleton, Sheona E , Geach, B S , Crookes, D , De Wit, M , Evans, J , von Maltitz, Graham P , Willis, C B , Kelatwang, S , Havemann, J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182262 , vital:43816 , xlink:href="https://hdl.handle.net/10520/EJC33860"
- Description: Natural resource valuation techniques have been applied in recent years to savannas and savanna resources in South and southern Africa. Results from these studies have been used to demonstrate the importance of savannas, and to assist in resource-use planning. Because these studies have been conducted to meet different research objectives a large number of disparities exist between studies. This makes comparison of results difficult and identification of underlying drivers of value is problematic. This paper discusses issues which can lead to differences in estimates of resource value, and makes recommendations for future studies to reduce incompatibilities. In particular, this paper recommends that future studies make full descriptions of the objectives of the study, the background characteristics of the study area (including the social, political, economic, cultural, and biophysical characteristics), the methods used, and assumptions made. In this way, the values reported from case studies may be used in other research and decision-making exercises.
- Full Text:
- Date Issued: 2001
Vein structure in relation to phloem loading in selected Ranunculaceae, Apocynaceae and Asclepiadaceae of the Eastern Cape
- Authors: Buswell, Alison Mary
- Date: 2001
- Subjects: Ranunculaceae Apocynaceae Asclepiadaceae Phloem Plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4243 , http://hdl.handle.net/10962/d1007277
- Description: The relationship between leaf architecture, vein anatomy and phloem ultrastructure, and that of possible routes from mesophyll cells to phloem and potential phloem loading method was investigated using species adapted to the southern African climate. The research was based on the hypothesis of Gamaiei and Van Bel, using nothern hemisphere species only (Gamalei 1985a, b, 1989, 1991, VanBeletal. 1988, Van Bel 1992, 1994, 1996, Van Bel & Gamalei 1991, 1992, Gamalei et al. 1992, 1994, 1996, Van Bel 1992a-c, 1993a, b, 1996). The thesis commenced with a survey ofleafarchitecture of the Ranunculaceae, Apocynaceae and Asclepiadaceae. Anatomical and ultrastructural studies followed. Leaf architecture was described according to Hickey (1973). Within the Ranuncuiaceae, leaf architecture was found to be marginally actinodromous. Venation pattern consisted of a widely spaced reticulum of delicate veins, especially in Ranunculus. Leaf architecture of the Apocynaceae was described as pinnate, camptodromous and brochidodromous. The Asclepiadaceae showed less uniformity in terms of leaf architecture, being pinnate and camptodromous, with mostly brochidodromous and, unexpectedly, eucamptodromous patterns of secondary venation. A predominantly common leaf architecture supported the move to amalgamate the two families. As the less advanced eucamptodromous arrangement could represent a more primitive branch of this huge family, the phylogenetic classification of the new amalgamated family is eagerly awaited for discussion. Allocation of vein order allowed comparisons between species and families to be drawn. Reticulum density and vein order anatomy was used to indicate potential routes from mesophyll to phloem. A definite contrast was obvious between the loose arrangement of mesophyll and veins in the mesic Ranunculus, and the close mesophyll and dense venation of the xeric apocynate and asclepiad species, and was related to habitat. Ultrastructural characteristics of companion cells, together with plasmodesmatal abundance, were considered especially important for the determination of minor vein configuration. Descriptions of plasmodesmatal distribution did not consider functional status. In this thesis, vein structure and ultrastructure were considered in relation to phloem loading, not as a demonstration thereof. All three families were designated minor vein configuration type 2a. Two interesting examples that did not adhere to the familial norm, viz. few plasmodesmata and normal companion cells, occurred in the Asclepiadaceae. Secamone alpinii had abundant aggregated plasmodesmata, forming a potential symplasmic continuum from mesophyll to companion cells. The question of plasmodesmatal functionality remained open. Ceropegia carnosa showed folding of the companion cell membrane, but no accompanying wall ingrowths. The folds were suggested to increase surface area for apoplasmic phloem loading in the noted absence of plasmodesmata. Loading routes and methods suggested were based on anatomical and ultrastructural evidence only. Whilst these results were supported by published data for other species of these families, the prediction of the Gamalei and Van Bel hypothesis did not hold true. The relatively primitive Ranunculaceae were expected to have the least advanced type 1 minor vein configuration, with abundance plasmodesmata providing a symplasmic phloem loading pathway. The relatively advanced Apocynaceae and Asc1epiadaceae were predicted to have the most progressive minor vein configuration, type 2b, with specialised transfer cells to maximise apoplasrnic uptake. As families with type 2a minor vein configurations, the Ranunculaceae were more advanced than expected and the Apocynaceae and Asc1epiadaceae less so.
- Full Text:
- Date Issued: 2001
- Authors: Buswell, Alison Mary
- Date: 2001
- Subjects: Ranunculaceae Apocynaceae Asclepiadaceae Phloem Plants -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4243 , http://hdl.handle.net/10962/d1007277
- Description: The relationship between leaf architecture, vein anatomy and phloem ultrastructure, and that of possible routes from mesophyll cells to phloem and potential phloem loading method was investigated using species adapted to the southern African climate. The research was based on the hypothesis of Gamaiei and Van Bel, using nothern hemisphere species only (Gamalei 1985a, b, 1989, 1991, VanBeletal. 1988, Van Bel 1992, 1994, 1996, Van Bel & Gamalei 1991, 1992, Gamalei et al. 1992, 1994, 1996, Van Bel 1992a-c, 1993a, b, 1996). The thesis commenced with a survey ofleafarchitecture of the Ranunculaceae, Apocynaceae and Asclepiadaceae. Anatomical and ultrastructural studies followed. Leaf architecture was described according to Hickey (1973). Within the Ranuncuiaceae, leaf architecture was found to be marginally actinodromous. Venation pattern consisted of a widely spaced reticulum of delicate veins, especially in Ranunculus. Leaf architecture of the Apocynaceae was described as pinnate, camptodromous and brochidodromous. The Asclepiadaceae showed less uniformity in terms of leaf architecture, being pinnate and camptodromous, with mostly brochidodromous and, unexpectedly, eucamptodromous patterns of secondary venation. A predominantly common leaf architecture supported the move to amalgamate the two families. As the less advanced eucamptodromous arrangement could represent a more primitive branch of this huge family, the phylogenetic classification of the new amalgamated family is eagerly awaited for discussion. Allocation of vein order allowed comparisons between species and families to be drawn. Reticulum density and vein order anatomy was used to indicate potential routes from mesophyll to phloem. A definite contrast was obvious between the loose arrangement of mesophyll and veins in the mesic Ranunculus, and the close mesophyll and dense venation of the xeric apocynate and asclepiad species, and was related to habitat. Ultrastructural characteristics of companion cells, together with plasmodesmatal abundance, were considered especially important for the determination of minor vein configuration. Descriptions of plasmodesmatal distribution did not consider functional status. In this thesis, vein structure and ultrastructure were considered in relation to phloem loading, not as a demonstration thereof. All three families were designated minor vein configuration type 2a. Two interesting examples that did not adhere to the familial norm, viz. few plasmodesmata and normal companion cells, occurred in the Asclepiadaceae. Secamone alpinii had abundant aggregated plasmodesmata, forming a potential symplasmic continuum from mesophyll to companion cells. The question of plasmodesmatal functionality remained open. Ceropegia carnosa showed folding of the companion cell membrane, but no accompanying wall ingrowths. The folds were suggested to increase surface area for apoplasmic phloem loading in the noted absence of plasmodesmata. Loading routes and methods suggested were based on anatomical and ultrastructural evidence only. Whilst these results were supported by published data for other species of these families, the prediction of the Gamalei and Van Bel hypothesis did not hold true. The relatively primitive Ranunculaceae were expected to have the least advanced type 1 minor vein configuration, with abundance plasmodesmata providing a symplasmic phloem loading pathway. The relatively advanced Apocynaceae and Asc1epiadaceae were predicted to have the most progressive minor vein configuration, type 2b, with specialised transfer cells to maximise apoplasrnic uptake. As families with type 2a minor vein configurations, the Ranunculaceae were more advanced than expected and the Apocynaceae and Asc1epiadaceae less so.
- Full Text:
- Date Issued: 2001
Voltammetric determination of nitric oxide on cobalt phthalocyanine modified microelectrodes
- Vilakazi, Sibulelo Lea, Nyokong, Tebello
- Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/291629 , vital:56893 , xlink:href="https://doi.org/10.1016/S0022-0728(01)00583-6"
- Description: The catalytic activity of a carbon fiber microelectrode modified with cobalt phthalocyanine (CoPc-ME) for the detection of nitric oxide in the presence of possible interfering molecules (dopamine and serotonin) is examined. A linear plot is observed for the variation of the catalytic currents with NO concentration in the presence of excess dopamine and serotonin, showing that NO may be determined in the presence of these molecules. However, oxidation currents due to serotonin were found to decrease with increase in NO concentration. The CoPc-ME could also detect NO added to blood or its components, the oxidation currents for NO, however, decreased rapidly with time. The decrease in currents was slower in blood serum, followed by whole blood, with a faster decrease being observed in blood plasma.
- Full Text:
- Date Issued: 2001
- Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/291629 , vital:56893 , xlink:href="https://doi.org/10.1016/S0022-0728(01)00583-6"
- Description: The catalytic activity of a carbon fiber microelectrode modified with cobalt phthalocyanine (CoPc-ME) for the detection of nitric oxide in the presence of possible interfering molecules (dopamine and serotonin) is examined. A linear plot is observed for the variation of the catalytic currents with NO concentration in the presence of excess dopamine and serotonin, showing that NO may be determined in the presence of these molecules. However, oxidation currents due to serotonin were found to decrease with increase in NO concentration. The CoPc-ME could also detect NO added to blood or its components, the oxidation currents for NO, however, decreased rapidly with time. The decrease in currents was slower in blood serum, followed by whole blood, with a faster decrease being observed in blood plasma.
- Full Text:
- Date Issued: 2001
Water quality and faunal studies in the Umzimvubu catchment, Eastern Cape, with particular emphasis on species as indicators of environmental change
- Madikizela, B R, Dye, Arthur H, O'Keeffe, Jay H
- Authors: Madikizela, B R , Dye, Arthur H , O'Keeffe, Jay H
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437730 , vital:73405 , ISBN 1 86845 705 2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/716-1-01.pdf
- Description: The primary aim of the project was to establish a water quality database and an in-ventory of aquatic fauna for the Umzimvubu River and its four main tributaries. The identification of species that are sensitive to environmental threats and that might be used as future indicators of environmental change, was the secondary aim. The results are outlined in Chapters 2, 3 and 4, while Chapter 5 reflects on conclusions and recommendations for further research. Based on the water quality data in Chapter 2 and macro-invertebrate scores (SASS4 and ASPT) in Chapter 3, the quality of water is good, suggesting that the catchment is not significantly degraded, ex-cept threats by soil erosion (Fig.2.15) leading to very high TSS loads (see Appendices 1- 3).
- Full Text:
- Date Issued: 2001
- Authors: Madikizela, B R , Dye, Arthur H , O'Keeffe, Jay H
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437730 , vital:73405 , ISBN 1 86845 705 2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/716-1-01.pdf
- Description: The primary aim of the project was to establish a water quality database and an in-ventory of aquatic fauna for the Umzimvubu River and its four main tributaries. The identification of species that are sensitive to environmental threats and that might be used as future indicators of environmental change, was the secondary aim. The results are outlined in Chapters 2, 3 and 4, while Chapter 5 reflects on conclusions and recommendations for further research. Based on the water quality data in Chapter 2 and macro-invertebrate scores (SASS4 and ASPT) in Chapter 3, the quality of water is good, suggesting that the catchment is not significantly degraded, ex-cept threats by soil erosion (Fig.2.15) leading to very high TSS loads (see Appendices 1- 3).
- Full Text:
- Date Issued: 2001
Woodlands or wastelands: Examining the value of South Africa's woodlands paper
- Shackleton, Charlie M, Willis, C B, Scholes, Robert J
- Authors: Shackleton, Charlie M , Willis, C B , Scholes, Robert J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182158 , vital:43805 , xlink:href="https://hdl.handle.net/10520/EJC33869"
- Description: The savanna woodlands are the largest biome in the country, constituting one-third of South Africa. They are also home to one-quarter of the population, with 70 % of the former homelands being in the savanna biome. Consequently, they have the potential to make a marked contribution to the national economy, both in the formal and informal sector. They are also valuable on a national scale in terms of the ecosystem services they provide, such as carbon storage, biodiversity and water yield. Until recently the real and potential values attached to South Africa's savannas have not been recognised in policy fora and government institutions. Recent policy changes, especially the National Forestry Action Programme and the National Forest Act, have attempted to remedy this situation. These policies have not filtered down to land owners and managers, nor have they resulted in a redirection of government resources. Thus, large areas remain subject to unsustainable use. It is necessary that the true value of woodlands be determined and acknowledged as a stimulus to government agencies, the private sector and local users to use this valuable resource sustainably.
- Full Text:
- Date Issued: 2001
- Authors: Shackleton, Charlie M , Willis, C B , Scholes, Robert J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182158 , vital:43805 , xlink:href="https://hdl.handle.net/10520/EJC33869"
- Description: The savanna woodlands are the largest biome in the country, constituting one-third of South Africa. They are also home to one-quarter of the population, with 70 % of the former homelands being in the savanna biome. Consequently, they have the potential to make a marked contribution to the national economy, both in the formal and informal sector. They are also valuable on a national scale in terms of the ecosystem services they provide, such as carbon storage, biodiversity and water yield. Until recently the real and potential values attached to South Africa's savannas have not been recognised in policy fora and government institutions. Recent policy changes, especially the National Forestry Action Programme and the National Forest Act, have attempted to remedy this situation. These policies have not filtered down to land owners and managers, nor have they resulted in a redirection of government resources. Thus, large areas remain subject to unsustainable use. It is necessary that the true value of woodlands be determined and acknowledged as a stimulus to government agencies, the private sector and local users to use this valuable resource sustainably.
- Full Text:
- Date Issued: 2001
Working conditions agreement for SACCAWU employees
- SACCAWU
- Authors: SACCAWU
- Date: 2001
- Subjects: SACCAWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/175924 , vital:42641
- Description: As a SACCAWU Staff Member it is important to know exactly what your Conditions of Service are hence this booklet. The Union believes in the principle of good and fair treatment of Staff and sees this as encouraging motivated and dedicated Officials. We have therefore tried to make Conditions as favourable as possible within the constraints of being a no-profit making organisation. In return, however the organisation does expect diligence, commitment and efficiency. Staff have the right before 1st March, every year to put forward proposals to* National Finance Committee in order to improve Working Conditions. Two Representatives elected from each Region will attend National Discussions/Engagements which shall put together a national mandate and elect Representatives to meet with NFC.
- Full Text:
- Date Issued: 2001
- Authors: SACCAWU
- Date: 2001
- Subjects: SACCAWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/175924 , vital:42641
- Description: As a SACCAWU Staff Member it is important to know exactly what your Conditions of Service are hence this booklet. The Union believes in the principle of good and fair treatment of Staff and sees this as encouraging motivated and dedicated Officials. We have therefore tried to make Conditions as favourable as possible within the constraints of being a no-profit making organisation. In return, however the organisation does expect diligence, commitment and efficiency. Staff have the right before 1st March, every year to put forward proposals to* National Finance Committee in order to improve Working Conditions. Two Representatives elected from each Region will attend National Discussions/Engagements which shall put together a national mandate and elect Representatives to meet with NFC.
- Full Text:
- Date Issued: 2001