Characterization of the hydantoin-hydrolysing system of Pseudomonas putida RU-KM3s
- Authors: Matcher, Gwynneth Felicity
- Date: 2005
- Subjects: Hydantoin Hydrolysis Pseudomonas Enzymes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3939 , http://hdl.handle.net/10962/d1003998
- Description: The biocatalytic conversion of 5-monosubstituted hydantoin derivatives to optically pure amino acids involves two reaction steps: the hydrolysis of hydantoin to N-carbamylamino acid by an hydantoinase or dihydropyrimidinase enzyme, followed by conversion of the Ncarbamylamino acid to the corresponding amino acid by an N-carbamoylase enzyme. This biocatalytic process has been successfully applied in several industrial processes for the production of enantiomerically pure amino acids used in the synthesis of pharmaceuticals, insecticides, hormones, and food additives. P. putida RU-KM3S was selected for study based on inherent high levels of hydantoinase and N-carbamoylase activity. Subsequent biocatalytic analysis of the enzyme activity within this strain revealed unique properties thus prompting further characterization. The main focus of this research was the isolation of the genes encoding the hydantoin-hydrolysing pathway in RU-KM3S. A genomic library was constructed and screened for heterologous expression of the hydantoin-hydrolysing enzymes. However, this approach was unsuccessful prompting the use of transposon mutagenesis in order to circumvent the drawbacks associated with complementation studies. The enzymes responsible for hydantoin-hydrolysis were identified by insertional inactivation as a dihydropyrimidinase and b-ureidopropionase encoded by dhp and bup respectively. A third open reading frame, encoding a putative transport protein, was identified between the dhp and bup genes and appeared to share a promoter with bup. Analysis of the amino acid sequence deduced from bup and dhp substantiated the distinctive properties and potential industrial application of the L-enantioselective b-ureidopropionase and provided targets for potential optimisation of the substrate-selectivity and activity of the dihydropyrimidinase by site directed mutagenesis. Several transposon-generated mutants with an altered phenotype for growth on minimal medium with hydantoin as the sole source of nitrogen were also isolated. Analysis of the insertion events in these mutants revealed disruptions of genes encoding key elements of the Ntr global regulatory pathway. However, inactivation of these genes had no effect on the dihydropyrimidinase and b-ureidopropionase activity levels. An additional mutant in which the gene coding for the dihydrolipoamide succinyltransferase, which is involved in the TCA cycle, was isolated with reduced levels of both dihydropyrimidinase and b-ureidopropionase activities. These results indicated that the hydantoin-hydrolysis pathway in RU-KM3S is regulated by carbon rather than nitrogen catabolite repression. This was confirmed by the reduction of hydantoin-hydrolysis in cells grown in excess carbon as opposed to nitrogen. Identification of a putative CRP-binding site within the promoter region of these enzymes further supported the regulatory role of carbon catabolite repression (CCR). As CCR in Pseudomonads is poorly understood, elucidation of the mechanism by which the hydantoinhydrolysing pathway in RU-KM3S is regulated would provide valuable insight into this complex process.
- Full Text:
- Date Issued: 2005
- Authors: Matcher, Gwynneth Felicity
- Date: 2005
- Subjects: Hydantoin Hydrolysis Pseudomonas Enzymes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3939 , http://hdl.handle.net/10962/d1003998
- Description: The biocatalytic conversion of 5-monosubstituted hydantoin derivatives to optically pure amino acids involves two reaction steps: the hydrolysis of hydantoin to N-carbamylamino acid by an hydantoinase or dihydropyrimidinase enzyme, followed by conversion of the Ncarbamylamino acid to the corresponding amino acid by an N-carbamoylase enzyme. This biocatalytic process has been successfully applied in several industrial processes for the production of enantiomerically pure amino acids used in the synthesis of pharmaceuticals, insecticides, hormones, and food additives. P. putida RU-KM3S was selected for study based on inherent high levels of hydantoinase and N-carbamoylase activity. Subsequent biocatalytic analysis of the enzyme activity within this strain revealed unique properties thus prompting further characterization. The main focus of this research was the isolation of the genes encoding the hydantoin-hydrolysing pathway in RU-KM3S. A genomic library was constructed and screened for heterologous expression of the hydantoin-hydrolysing enzymes. However, this approach was unsuccessful prompting the use of transposon mutagenesis in order to circumvent the drawbacks associated with complementation studies. The enzymes responsible for hydantoin-hydrolysis were identified by insertional inactivation as a dihydropyrimidinase and b-ureidopropionase encoded by dhp and bup respectively. A third open reading frame, encoding a putative transport protein, was identified between the dhp and bup genes and appeared to share a promoter with bup. Analysis of the amino acid sequence deduced from bup and dhp substantiated the distinctive properties and potential industrial application of the L-enantioselective b-ureidopropionase and provided targets for potential optimisation of the substrate-selectivity and activity of the dihydropyrimidinase by site directed mutagenesis. Several transposon-generated mutants with an altered phenotype for growth on minimal medium with hydantoin as the sole source of nitrogen were also isolated. Analysis of the insertion events in these mutants revealed disruptions of genes encoding key elements of the Ntr global regulatory pathway. However, inactivation of these genes had no effect on the dihydropyrimidinase and b-ureidopropionase activity levels. An additional mutant in which the gene coding for the dihydrolipoamide succinyltransferase, which is involved in the TCA cycle, was isolated with reduced levels of both dihydropyrimidinase and b-ureidopropionase activities. These results indicated that the hydantoin-hydrolysis pathway in RU-KM3S is regulated by carbon rather than nitrogen catabolite repression. This was confirmed by the reduction of hydantoin-hydrolysis in cells grown in excess carbon as opposed to nitrogen. Identification of a putative CRP-binding site within the promoter region of these enzymes further supported the regulatory role of carbon catabolite repression (CCR). As CCR in Pseudomonads is poorly understood, elucidation of the mechanism by which the hydantoinhydrolysing pathway in RU-KM3S is regulated would provide valuable insight into this complex process.
- Full Text:
- Date Issued: 2005
Clay sculpture within an object relational therapy: a phenomenological-hermeneutic case study
- Authors: Masters, Carin-Lee
- Date: 2005
- Subjects: Art -- Psychology , Art therapy -- Case studies , Psychotherapy , Modeling -- Therapeutic use
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3015 , http://hdl.handle.net/10962/d1002524 , Art -- Psychology , Art therapy -- Case studies , Psychotherapy , Modeling -- Therapeutic use
- Description: The overall aim of this thesis is to explore the process of working with the Edwards claywork method with a psychotherapy client who had significant relational difficulties and feared being exposed as defective. Within this there are particular aims: Firstly, to investigate whether the distancing that art therapy can create, can help the client with relational difficulties to tolerate unexpressed disavowed feelings, in particular her sense of shame about being exposed as defective; and secondly, to examine whether material evoked through the claywork process can assist in furthering the psychological formulation of this kind of client. The research was a phenomenological-hermeneutic case study of a psychotherapy client, called Kim. Kim’s experience of therapy, including two claywork sessions, was documented. This comprises a thematic narrative of her therapy process prior to the claywork process, as well as a thematic narrative focusing on the two claywork sessions. Her clay sculpture was photographed and alphabetically labeled according to the chronological order in which she made the eight pieces comprising her sculpture. A hermeneutic reading of the narratives was conducted using theoretical perspectives including object relations, Adlerian psychology and art therapy. It was concluded that, firstly, the distancing that art therapy can create does help the client, who is afraid of being exposed as defective, to tolerate previously disavowed and unexpressed feelings; and secondly, art therapy such as the Edwards claywork method, does deepen psychological formulation of the client’s affective and relational difficulties. However, although the image may graphically symbolize unconscious aspects of a client’s psyche, the present study illustrates that a client may not always be able to enter into a relationship with the image or dialogue between conscious and unconscious states. In this respect, the present study focuses on aspects of art therapy of which there is limited literature.
- Full Text:
- Date Issued: 2005
- Authors: Masters, Carin-Lee
- Date: 2005
- Subjects: Art -- Psychology , Art therapy -- Case studies , Psychotherapy , Modeling -- Therapeutic use
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3015 , http://hdl.handle.net/10962/d1002524 , Art -- Psychology , Art therapy -- Case studies , Psychotherapy , Modeling -- Therapeutic use
- Description: The overall aim of this thesis is to explore the process of working with the Edwards claywork method with a psychotherapy client who had significant relational difficulties and feared being exposed as defective. Within this there are particular aims: Firstly, to investigate whether the distancing that art therapy can create, can help the client with relational difficulties to tolerate unexpressed disavowed feelings, in particular her sense of shame about being exposed as defective; and secondly, to examine whether material evoked through the claywork process can assist in furthering the psychological formulation of this kind of client. The research was a phenomenological-hermeneutic case study of a psychotherapy client, called Kim. Kim’s experience of therapy, including two claywork sessions, was documented. This comprises a thematic narrative of her therapy process prior to the claywork process, as well as a thematic narrative focusing on the two claywork sessions. Her clay sculpture was photographed and alphabetically labeled according to the chronological order in which she made the eight pieces comprising her sculpture. A hermeneutic reading of the narratives was conducted using theoretical perspectives including object relations, Adlerian psychology and art therapy. It was concluded that, firstly, the distancing that art therapy can create does help the client, who is afraid of being exposed as defective, to tolerate previously disavowed and unexpressed feelings; and secondly, art therapy such as the Edwards claywork method, does deepen psychological formulation of the client’s affective and relational difficulties. However, although the image may graphically symbolize unconscious aspects of a client’s psyche, the present study illustrates that a client may not always be able to enter into a relationship with the image or dialogue between conscious and unconscious states. In this respect, the present study focuses on aspects of art therapy of which there is limited literature.
- Full Text:
- Date Issued: 2005
Coastal dune dynamics and management at the Bushman's River mouth, Kenton-on-Sea
- Authors: Fraser, Claire
- Date: 2005
- Subjects: Sand dunes -- South Africa -- Management , Sand dune ecology -- South Africa -- Kenton-on-Sea , Coastal ecology -- South Africa -- Kenton-on-Sea , Coastal zone management -- South Africa -- Kenton-on-Sea
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4192 , http://hdl.handle.net/10962/d1003761 , Sand dunes -- South Africa -- Management , Sand dune ecology -- South Africa -- Kenton-on-Sea , Coastal ecology -- South Africa -- Kenton-on-Sea , Coastal zone management -- South Africa -- Kenton-on-Sea
- Description: A study of the dynamics and functions of a coastal dunefield at the Bushman’s River Mouth in Kenton-on-Sea was conducted to provide essential information for the formulation of a management strategy based on an ecosystem approach. Bi-monthly tacheometric surveys were undertaken at the Westbourne Road Car Park dunefield to investigate the sedimentological processes. Changes in the topography, the amount and rate of sand accretion were monitored. Accretion and progradation were the dominant long-term sedimentological processes at the site. Long-term spatial variation in these processes corresponded to the temporal pattern of sedimentation in the river mouth while short-term variation resulted from dynamics inherent to the types of dunes present. Factors affecting aeolian accretion at the site are topography, river mouth configuration, dune types and the presence of vegetation as well as the seasonal wind regime. A vegetation study, recording species present, cover and abundance of the plants along the surveyed transects, was also conducted to examine the progressive establishment of vegetation. Five plant communities were discerned namely, saltmarsh, pioneer, enriched pioneer, open scrub, closed scrub and scrub-thicket communities. The spatial distribution of these communities coincided with the north-westerly development of the sandbank. A successional trend in community change occurred along a gradient of increasing diversity, complexity and age. Initially, autogenic changes wrought by pioneer species facilitated the recruitment and survival of other species and commenced succession at the study site. Multiple successional pathways were discussed in relation to subsequent species establishment that occurred after facilitation. The amalgamation of ecological data with a social study in the form of public perception surveys allowed for a greater understanding of the present interactions between the ecosystem and the demands placed on it. The area primarily functions as a recreational site that offered numerous beach and water-related activities. A lack of information regarding the ecology and management programmes influenced public perception of the environment and management issues in general. Different management perspectives and the use of the information presented in this study were also discussed.
- Full Text:
- Date Issued: 2005
- Authors: Fraser, Claire
- Date: 2005
- Subjects: Sand dunes -- South Africa -- Management , Sand dune ecology -- South Africa -- Kenton-on-Sea , Coastal ecology -- South Africa -- Kenton-on-Sea , Coastal zone management -- South Africa -- Kenton-on-Sea
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4192 , http://hdl.handle.net/10962/d1003761 , Sand dunes -- South Africa -- Management , Sand dune ecology -- South Africa -- Kenton-on-Sea , Coastal ecology -- South Africa -- Kenton-on-Sea , Coastal zone management -- South Africa -- Kenton-on-Sea
- Description: A study of the dynamics and functions of a coastal dunefield at the Bushman’s River Mouth in Kenton-on-Sea was conducted to provide essential information for the formulation of a management strategy based on an ecosystem approach. Bi-monthly tacheometric surveys were undertaken at the Westbourne Road Car Park dunefield to investigate the sedimentological processes. Changes in the topography, the amount and rate of sand accretion were monitored. Accretion and progradation were the dominant long-term sedimentological processes at the site. Long-term spatial variation in these processes corresponded to the temporal pattern of sedimentation in the river mouth while short-term variation resulted from dynamics inherent to the types of dunes present. Factors affecting aeolian accretion at the site are topography, river mouth configuration, dune types and the presence of vegetation as well as the seasonal wind regime. A vegetation study, recording species present, cover and abundance of the plants along the surveyed transects, was also conducted to examine the progressive establishment of vegetation. Five plant communities were discerned namely, saltmarsh, pioneer, enriched pioneer, open scrub, closed scrub and scrub-thicket communities. The spatial distribution of these communities coincided with the north-westerly development of the sandbank. A successional trend in community change occurred along a gradient of increasing diversity, complexity and age. Initially, autogenic changes wrought by pioneer species facilitated the recruitment and survival of other species and commenced succession at the study site. Multiple successional pathways were discussed in relation to subsequent species establishment that occurred after facilitation. The amalgamation of ecological data with a social study in the form of public perception surveys allowed for a greater understanding of the present interactions between the ecosystem and the demands placed on it. The area primarily functions as a recreational site that offered numerous beach and water-related activities. A lack of information regarding the ecology and management programmes influenced public perception of the environment and management issues in general. Different management perspectives and the use of the information presented in this study were also discussed.
- Full Text:
- Date Issued: 2005
Conceptualizing and implementing the meaning of Africa's new partnership with the industrialized north : implications and possibilities for the renaissance
- Authors: Somhlaba, Zamokwakhe Ludidi
- Date: 2005
- Subjects: New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2841 , http://hdl.handle.net/10962/d1004655 , New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Description: This study is a contribution to the on-going debate about the path that Africa has taken in realising the vision of its renewal. The central theme of the study is the idea of Africa's 'new partnership' with the industrialised North, which is envisaged under the New Partnership for Africa's Development (NEPAD). Acknowledging that asymmetrical partnerships have existed between Africa and the North, particularly in the last century, the question this study poses is: to what extent does the idea of the 'new partnership' represent something new? The study argues two points. Firstly, it argues that the idea of the new partnership has become a terrain of contestation between the Africanist and the post-modernist social forces. Secondly, the study argues that it is unlikely that conceptualising the idea of the new partnership in post-modernist terms will result in sustainable development and rebirth of Africa. That is particularly the case, because post-modernity suggests a certain degree of loyalty to the prevailing and asymmetrical global order. Against this background, the study concludes that the extent to which Africa will enjoy the benefits of a truly revised partnership with the North, and thus fulfil the vision of its rebirth, will be determined, by and large, by the modalities of accommodation and struggle between these social forces.
- Full Text:
- Date Issued: 2005
- Authors: Somhlaba, Zamokwakhe Ludidi
- Date: 2005
- Subjects: New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2841 , http://hdl.handle.net/10962/d1004655 , New Partnership for Africa's Development , Sustainable development -- Africa , Economic development -- Africa , Africa -- Foreign economic relations , Africa -- Economic conditions -- 1960-
- Description: This study is a contribution to the on-going debate about the path that Africa has taken in realising the vision of its renewal. The central theme of the study is the idea of Africa's 'new partnership' with the industrialised North, which is envisaged under the New Partnership for Africa's Development (NEPAD). Acknowledging that asymmetrical partnerships have existed between Africa and the North, particularly in the last century, the question this study poses is: to what extent does the idea of the 'new partnership' represent something new? The study argues two points. Firstly, it argues that the idea of the new partnership has become a terrain of contestation between the Africanist and the post-modernist social forces. Secondly, the study argues that it is unlikely that conceptualising the idea of the new partnership in post-modernist terms will result in sustainable development and rebirth of Africa. That is particularly the case, because post-modernity suggests a certain degree of loyalty to the prevailing and asymmetrical global order. Against this background, the study concludes that the extent to which Africa will enjoy the benefits of a truly revised partnership with the North, and thus fulfil the vision of its rebirth, will be determined, by and large, by the modalities of accommodation and struggle between these social forces.
- Full Text:
- Date Issued: 2005
Consolidating democracy, building civil society : the South African Council of Churches in post-apartheid South Africa and its policy of critical solidarity with the state
- Authors: Joseph, Stacey-Leigh
- Date: 2005
- Subjects: South African Council of Churches Church and state -- South Africa Christianity and politics -- South Africa Apartheid -- Religious aspects -- South Africa AIDS (Disease) -- Government policy -- South Africa Debts, External -- South Africa South Africa -- Foreign relations -- Zimbabwe South Africa -- Politics and government -- 1994
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2874 , http://hdl.handle.net/10962/d1007957
- Description: The South African Council of Churches (SACC) played an extremely crucial role during the struggle against apartheid. The role of the SACC was first and foremost to provide a voice for the voiceless. It managed, among other tasks, to actively fill the void left by movements banned by the illegitimate apartheid government. As a result of its fight against the inequalities that existed in South Africa, its work adopted a political character. In the aftermath of post-apartheid South Africa, the SACC was left with the task of redefining its role within South African society and civil society, specifically. The euphoric sentiment in the mid-1990s was in part reflected in the SACC. However, the conclusion reached by the Council in 1995 was that it would also play a role of 'critical solidarity' which essentially meant that it would not shy away from attacking the government when the need arose. Since 1994, the South African government has implemented a number of policies that do not appear to be in the immediate interest of the majority of South African citizens atld have brought church and state into conflict. This thesis attempts to tackle three issues which are pertinent to the South African situation and which shed light on state-civil society interactions. These issues are HIV I Aids, the question of odious debt and the Zimbabwe crisis. By using both primary and secondary sources, the SACC's responses to government's handling of these matters will be compared with the responses of the South African Catholic Bishops Conference in order to determine their relationships with government. The conclusion of this investigation is that the SACC has in fact managed to maintain a position of critical solidarity. It has been faced with numerous challenges with regard to maintaining the fragile boundary of alliance with government on the one hand, and becoming anti-government on the other. However, by forming alliances with other civil society actors as well as fostering a relationship with government in order to facilitate mediation this dissertation argues that the SACC has become an essential member of South Africa's vibrant civil society.
- Full Text:
- Date Issued: 2005
- Authors: Joseph, Stacey-Leigh
- Date: 2005
- Subjects: South African Council of Churches Church and state -- South Africa Christianity and politics -- South Africa Apartheid -- Religious aspects -- South Africa AIDS (Disease) -- Government policy -- South Africa Debts, External -- South Africa South Africa -- Foreign relations -- Zimbabwe South Africa -- Politics and government -- 1994
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2874 , http://hdl.handle.net/10962/d1007957
- Description: The South African Council of Churches (SACC) played an extremely crucial role during the struggle against apartheid. The role of the SACC was first and foremost to provide a voice for the voiceless. It managed, among other tasks, to actively fill the void left by movements banned by the illegitimate apartheid government. As a result of its fight against the inequalities that existed in South Africa, its work adopted a political character. In the aftermath of post-apartheid South Africa, the SACC was left with the task of redefining its role within South African society and civil society, specifically. The euphoric sentiment in the mid-1990s was in part reflected in the SACC. However, the conclusion reached by the Council in 1995 was that it would also play a role of 'critical solidarity' which essentially meant that it would not shy away from attacking the government when the need arose. Since 1994, the South African government has implemented a number of policies that do not appear to be in the immediate interest of the majority of South African citizens atld have brought church and state into conflict. This thesis attempts to tackle three issues which are pertinent to the South African situation and which shed light on state-civil society interactions. These issues are HIV I Aids, the question of odious debt and the Zimbabwe crisis. By using both primary and secondary sources, the SACC's responses to government's handling of these matters will be compared with the responses of the South African Catholic Bishops Conference in order to determine their relationships with government. The conclusion of this investigation is that the SACC has in fact managed to maintain a position of critical solidarity. It has been faced with numerous challenges with regard to maintaining the fragile boundary of alliance with government on the one hand, and becoming anti-government on the other. However, by forming alliances with other civil society actors as well as fostering a relationship with government in order to facilitate mediation this dissertation argues that the SACC has become an essential member of South Africa's vibrant civil society.
- Full Text:
- Date Issued: 2005
Contending issues in South Africa's foreign policy : universalism versus economic national interest : the case of South Africa's arms sales to 'pariah states' 1994-1999
- Authors: Othieno, Timothy
- Date: 2005
- Subjects: South Africa -- Foreign relations -- 1994- South Africa -- Politics and government -- 1994- South Africa -- Foreign economic relations Arms transfers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2868 , http://hdl.handle.net/10962/d1007712
- Description: This study examines post-apartheid South African foreign policy under former President Nelson Mandela, and the apparent ambiguities that were its recurrent feature in the period from 1994 to 1999. Its focus is on the inherent irreconcilability of the economic national interests and the foreign policy principles which included the promotion of and respect for universalist principles and interests such as human rights, democracy, international peace and security. In examining South African foreign policy during this period, it would appear that the country was trapped between two competing priorities: the need to promote "universalist" principles and the need to satisfy its national economic interests. The main aim of the study is to explain how this "irreconcilability" between universalist principles and national economic interests would later create ambiguities and contradictions in South Africa's foreign policy, weaken respect for its foreign policy principles, and ultimately lead to ideological failure among politicians who employed 'short-term gain' policy decision-making in dealing with 'pariah states'. The study further demonstrates that "realist" national interests are frequently short-term, realizable and vital for a country, while universalist interests are long-term, idealistic and usually not easily realizable. It will be argued, therefore, that a country faced with making decisions about its vital national interests, will not make efforts to pursue long-term universalist interests if that choice would in any way endanger its fundamental national interests. In order to better assess this ambiguity, this thesis will provide a case study of Pretoria's arms sales to 'pariah states' during the period. The purpose of this study is not to attempt to explain all of the issues around post-apartheid foreign policymaking, or even to argue whether the sale of arms to 'pariah states' was 'politically incorrect', but to provide a 'piece of the puzzle' which might explain how the social and economic situation may have compelled Pretoria to sell arms when these actions disregarded universalist principles of foreign policy. The conclusion seems to confirm the realist view that universal values and principles can be regarded only when they are in harmony with a state's perceived self-interests.
- Full Text:
- Date Issued: 2005
- Authors: Othieno, Timothy
- Date: 2005
- Subjects: South Africa -- Foreign relations -- 1994- South Africa -- Politics and government -- 1994- South Africa -- Foreign economic relations Arms transfers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2868 , http://hdl.handle.net/10962/d1007712
- Description: This study examines post-apartheid South African foreign policy under former President Nelson Mandela, and the apparent ambiguities that were its recurrent feature in the period from 1994 to 1999. Its focus is on the inherent irreconcilability of the economic national interests and the foreign policy principles which included the promotion of and respect for universalist principles and interests such as human rights, democracy, international peace and security. In examining South African foreign policy during this period, it would appear that the country was trapped between two competing priorities: the need to promote "universalist" principles and the need to satisfy its national economic interests. The main aim of the study is to explain how this "irreconcilability" between universalist principles and national economic interests would later create ambiguities and contradictions in South Africa's foreign policy, weaken respect for its foreign policy principles, and ultimately lead to ideological failure among politicians who employed 'short-term gain' policy decision-making in dealing with 'pariah states'. The study further demonstrates that "realist" national interests are frequently short-term, realizable and vital for a country, while universalist interests are long-term, idealistic and usually not easily realizable. It will be argued, therefore, that a country faced with making decisions about its vital national interests, will not make efforts to pursue long-term universalist interests if that choice would in any way endanger its fundamental national interests. In order to better assess this ambiguity, this thesis will provide a case study of Pretoria's arms sales to 'pariah states' during the period. The purpose of this study is not to attempt to explain all of the issues around post-apartheid foreign policymaking, or even to argue whether the sale of arms to 'pariah states' was 'politically incorrect', but to provide a 'piece of the puzzle' which might explain how the social and economic situation may have compelled Pretoria to sell arms when these actions disregarded universalist principles of foreign policy. The conclusion seems to confirm the realist view that universal values and principles can be regarded only when they are in harmony with a state's perceived self-interests.
- Full Text:
- Date Issued: 2005
Creating a relationship: a discourse analysis focusing on the construction of identities and relationships in distance education materials for a teacher upgrade programme
- Authors: Van der Mescht, Caroline
- Date: 2005
- Subjects: Distance education -- South Africa Teachers -- Training of -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1467 , http://hdl.handle.net/10962/d1003348
- Description: Distance education, and therefore the writing of distance materials, is a growing field in South Africa. This makes it potentially a site of innovation and change as writers experiment with ways of creating effective teaching situations at long range. The Fort Hare Distance Education Project materials seem to be a response to both the increased need for teacher upgrade programmes and the need for innovation to tailor those programmes to the needs of local teachers in a changing society. This innovative attempt to communicate with tertiary distance students has unusual features which suggest that they are worth investigation. Using discourse analysis, including the work of Scollon and Scollon on politeness theory, and an analysis of visual elements using categories developed by Kress and van Leeuwen, this study focuses on 18 pages of a sample text, booklet 9, “A Whole Language Approach,” to investigate how the writer-reader relationship and the identity of the reader are constructed. The analysis reveals a complex, interlocking construction of identity and relationship, producing and resolving apparent contradictions as writers move from one position to another while they negotiate their ongoing and evolving relationship with the readers. Features of identity and relationship operating through the text include issues of authority, changing roles of teachers and learners, trust, what constitutes appropriate language and materials, acknowledging prior learning in under-qualified professionals, ownership of the text, hierarchy and egalitarianism, and stereotyping. The study suggests that the Fort Hare Distance Project materials offer an example of strategies suited to local students which should benefit those who design such courses. It further suggests that visual analysis together with discourse analysis provides insights which seem not to be accessible through a study of the verbal text, and that an analysis of visual elements may widen a researcher’s options. It reveals ways in which writers can negotiate conflicting positions and consciously or unconsciously attempt to resolve contradictions and ambivalence. It suggests issues which need to be negotiated in any text written in South Africa for a similar audience.
- Full Text:
- Date Issued: 2005
- Authors: Van der Mescht, Caroline
- Date: 2005
- Subjects: Distance education -- South Africa Teachers -- Training of -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1467 , http://hdl.handle.net/10962/d1003348
- Description: Distance education, and therefore the writing of distance materials, is a growing field in South Africa. This makes it potentially a site of innovation and change as writers experiment with ways of creating effective teaching situations at long range. The Fort Hare Distance Education Project materials seem to be a response to both the increased need for teacher upgrade programmes and the need for innovation to tailor those programmes to the needs of local teachers in a changing society. This innovative attempt to communicate with tertiary distance students has unusual features which suggest that they are worth investigation. Using discourse analysis, including the work of Scollon and Scollon on politeness theory, and an analysis of visual elements using categories developed by Kress and van Leeuwen, this study focuses on 18 pages of a sample text, booklet 9, “A Whole Language Approach,” to investigate how the writer-reader relationship and the identity of the reader are constructed. The analysis reveals a complex, interlocking construction of identity and relationship, producing and resolving apparent contradictions as writers move from one position to another while they negotiate their ongoing and evolving relationship with the readers. Features of identity and relationship operating through the text include issues of authority, changing roles of teachers and learners, trust, what constitutes appropriate language and materials, acknowledging prior learning in under-qualified professionals, ownership of the text, hierarchy and egalitarianism, and stereotyping. The study suggests that the Fort Hare Distance Project materials offer an example of strategies suited to local students which should benefit those who design such courses. It further suggests that visual analysis together with discourse analysis provides insights which seem not to be accessible through a study of the verbal text, and that an analysis of visual elements may widen a researcher’s options. It reveals ways in which writers can negotiate conflicting positions and consciously or unconsciously attempt to resolve contradictions and ambivalence. It suggests issues which need to be negotiated in any text written in South Africa for a similar audience.
- Full Text:
- Date Issued: 2005
Developing an environmental education strategy framework: a case study of the Endangered Wildlife Trust (EWT)
- Authors: O'Grady, Janis
- Date: 2005
- Subjects: Endangered Wildlife Trust Environmental education -- South Africa Conservation of natural resources -- South Africa Biodiversity -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1494 , http://hdl.handle.net/10962/d1003375
- Description: The study focused on the development of an environmental education (EE) strategy framework in the Endangered Wildlife Trust (EWT) of South Africa. Evidence shows that the roles of conservation and biodiversity education could potentially be merged towards producing a practical strategy, beneficial to the organisation and its individual staff members. Questionnaires, interviews and the individual perceptions of staff members, as well as the analysis of relevant documents, suggested that the potential for the practice of EE towards the development of an EE strategy within the organisation is substantial. EWT staff members can contribute towards a change in the way that South Africans think about conservation and nature. Environmental ethics need to be promoted and understood by all. Within the EWT, environmental education activities are in place and diverse, yet they lack any form of monitoring and evaluation. The Trust is already practicing a form of EE but the potential to do more and the opportunities for expansion are unlimited.
- Full Text:
- Date Issued: 2005
- Authors: O'Grady, Janis
- Date: 2005
- Subjects: Endangered Wildlife Trust Environmental education -- South Africa Conservation of natural resources -- South Africa Biodiversity -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1494 , http://hdl.handle.net/10962/d1003375
- Description: The study focused on the development of an environmental education (EE) strategy framework in the Endangered Wildlife Trust (EWT) of South Africa. Evidence shows that the roles of conservation and biodiversity education could potentially be merged towards producing a practical strategy, beneficial to the organisation and its individual staff members. Questionnaires, interviews and the individual perceptions of staff members, as well as the analysis of relevant documents, suggested that the potential for the practice of EE towards the development of an EE strategy within the organisation is substantial. EWT staff members can contribute towards a change in the way that South Africans think about conservation and nature. Environmental ethics need to be promoted and understood by all. Within the EWT, environmental education activities are in place and diverse, yet they lack any form of monitoring and evaluation. The Trust is already practicing a form of EE but the potential to do more and the opportunities for expansion are unlimited.
- Full Text:
- Date Issued: 2005
Developing strategies for creating an environmental focus in a school: narrating the change process
- Authors: Hope, Megan Samantha
- Date: 2005
- Subjects: Environmental education Educational change School environment
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1946 , http://hdl.handle.net/10962/d1008093
- Description: Effective environmental education goes beyond raising environmental awareness and developing positive environmental values, to the encouragement of personal responsibility and action in response to contextual environmental issues in particular. The whole school approach has been advocated as the best approach to environmental education, based on the assumption that the values and attitudes espoused in the classroom need to be reflected in the day-to-day school practice. By practising what they teach, schools reinforce values with action. In contrast, inconsistencies between the formal and non-formal curriculum may lead young people to question the integrity of their teachers or condition them to accept such inconsistencies as cultural and social norms, which in turn may lead to apathy about the environment. Adjustments to the ethos of a school to foreground the environment, both within the curriculum , the management of the school and the behaviour of teachers, pupils and support staff, is not a straightforward undertaking. Institutional factors influence the change process in schools and each school presents a unique context. It is, therefore, difficult to develop a general strategy for the evolution of an environmental ethos. This case study narrates an attempt to implement a change towards an improved environmental focus in a school, and focuses on developing an understanding of how available resources can assist this process while engaging with complexity of change.
- Full Text:
- Date Issued: 2005
- Authors: Hope, Megan Samantha
- Date: 2005
- Subjects: Environmental education Educational change School environment
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1946 , http://hdl.handle.net/10962/d1008093
- Description: Effective environmental education goes beyond raising environmental awareness and developing positive environmental values, to the encouragement of personal responsibility and action in response to contextual environmental issues in particular. The whole school approach has been advocated as the best approach to environmental education, based on the assumption that the values and attitudes espoused in the classroom need to be reflected in the day-to-day school practice. By practising what they teach, schools reinforce values with action. In contrast, inconsistencies between the formal and non-formal curriculum may lead young people to question the integrity of their teachers or condition them to accept such inconsistencies as cultural and social norms, which in turn may lead to apathy about the environment. Adjustments to the ethos of a school to foreground the environment, both within the curriculum , the management of the school and the behaviour of teachers, pupils and support staff, is not a straightforward undertaking. Institutional factors influence the change process in schools and each school presents a unique context. It is, therefore, difficult to develop a general strategy for the evolution of an environmental ethos. This case study narrates an attempt to implement a change towards an improved environmental focus in a school, and focuses on developing an understanding of how available resources can assist this process while engaging with complexity of change.
- Full Text:
- Date Issued: 2005
Development and assessment of medicines information for antiretroviral therapy in Sub-Saharan Africa
- Authors: Mwingira, Betty
- Date: 2005
- Subjects: AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3779 , http://hdl.handle.net/10962/d1003257 , AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Full Text:
- Date Issued: 2005
Development and assessment of medicines information for antiretroviral therapy in Sub-Saharan Africa
- Authors: Mwingira, Betty
- Date: 2005
- Subjects: AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3779 , http://hdl.handle.net/10962/d1003257 , AIDS (Disease) -- Africa, Sub-Saharan , AIDS (Disease) -- Treatment -- Africa, Sub-Saharan , AIDS (Disease) -- Juvenile literature -- Africa, Sub-Saharan , HIV infections -- Treatment -- Africa, Sub-Saharan , HIV infections -- Africa, Sub-Saharan , Antiretroviral agents -- Africa, Sub-Saharan , HIV-positive persons -- Care -- Africa, Sub-Saharan , Hiv-positive persons -- Medical care -- Africa, Sub-Saharan , AIDS (Disease) -- Study and teaching -- Africa, Sub-Saharan
- Full Text:
- Date Issued: 2005
Development of an experimental system to investigate the interaction between the Helicoverpa armigera stunt virus capsid protein and viral RNA
- Authors: Nel, Andrew James Mascré
- Date: 2005
- Subjects: Helicoverpa armigera , RNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3946 , http://hdl.handle.net/10962/d1004005 , Helicoverpa armigera , RNA viruses
- Description: Tetraviruses are entomopathogenic viruses that propagate solely in lepidopteran hosts. Viruses of this group possess non-enveloped 38- to 40-nm capsids arranged in T = 4 surface symmetry. The viral genome consists of one or two single stranded positive sense RNA strands, which define the two genera of this family, the monopartite betatetraviruses and the bipartite omegatetraviruses. Two extensively studied members of the tetraviruses are the omegatetraviruses, Helicoverpa armigera stunt virus (HaSV) and the closely related Nudaurelia capensis ω virus (NωV). The larger genomic strand of HaSV (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71-kDa capsid precursor protein (p71). The pro-capsid is assembled from 240 copies of p71, which undergo a maturation auto-catalytic cleavage into the 64-kDa (p64) capsid protein and a 7-kDa peptide (p7) forming the capsid shell. The mechanism for the recognition and packaging of the viral genome is poorly understood for these viruses. The principle objective of the research described in this study was to develop in vitro and in vivo experimental systems to investigate interactions between the N terminal domain of HaSV p71 and viral RNAs. More specifically, the two positively charged clusters of predominantly arginine residues that are conserved amongst tetraviruses and the structurally analologous nodaviruses capsid protomers’ N terminal domains were investigated. An in vitro RNA-protein “pull down” system was developed using the rapid protein purification technique of the IMPACTTM-CN system. The coding sequence of the N terminal domain of p71 was fused to that of a chitin binding affinity tag (intein). This fusion protein was used as protein bait for the viral RNA. It was proposed that if RNA interacted with the fusion protein, it would be pulled down by the mass of affinity matrix and be precipitated and fluoresce when analysed by agarose gel electrophoresis using ethidium bromide. Despite optimisation of the in vitro assay, results were affected by the interaction between the intein-tag and nucleic acids, the state of the expressed fusion protein (in particular self-cleavage) and the excessive fluorescence present on the gels. The ADH2-GAPDH yeast expression system was used to investigate the in vivo assembly of p71 containing deletions of either one or both clusters within N terminal domain. It was found that all p71 mutants were expressed with the exception of the mutant containing a deletion of the second cluster. The reasons for this still require further investigation. The expressed p71 mutants were not processed into p64 and were degraded in vivo. In addition, an experimental attempt to purify assembled p71 mutant VLPs was unsuccessful. The assembly defect of p71 mutants emphasised the significance of the clusters, which are possibly required for interaction with viral RNAs for efficient VLP assembly. The results of this study suggest that an alternative tag or in vitro RNA-protein interaction assay be used. In addition, further experiments are required to investigate whether the co-expression of full length viral RNAs are required to rescue the in vivo assembly defect of p71 mutants into VLPs.
- Full Text:
- Date Issued: 2005
- Authors: Nel, Andrew James Mascré
- Date: 2005
- Subjects: Helicoverpa armigera , RNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3946 , http://hdl.handle.net/10962/d1004005 , Helicoverpa armigera , RNA viruses
- Description: Tetraviruses are entomopathogenic viruses that propagate solely in lepidopteran hosts. Viruses of this group possess non-enveloped 38- to 40-nm capsids arranged in T = 4 surface symmetry. The viral genome consists of one or two single stranded positive sense RNA strands, which define the two genera of this family, the monopartite betatetraviruses and the bipartite omegatetraviruses. Two extensively studied members of the tetraviruses are the omegatetraviruses, Helicoverpa armigera stunt virus (HaSV) and the closely related Nudaurelia capensis ω virus (NωV). The larger genomic strand of HaSV (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71-kDa capsid precursor protein (p71). The pro-capsid is assembled from 240 copies of p71, which undergo a maturation auto-catalytic cleavage into the 64-kDa (p64) capsid protein and a 7-kDa peptide (p7) forming the capsid shell. The mechanism for the recognition and packaging of the viral genome is poorly understood for these viruses. The principle objective of the research described in this study was to develop in vitro and in vivo experimental systems to investigate interactions between the N terminal domain of HaSV p71 and viral RNAs. More specifically, the two positively charged clusters of predominantly arginine residues that are conserved amongst tetraviruses and the structurally analologous nodaviruses capsid protomers’ N terminal domains were investigated. An in vitro RNA-protein “pull down” system was developed using the rapid protein purification technique of the IMPACTTM-CN system. The coding sequence of the N terminal domain of p71 was fused to that of a chitin binding affinity tag (intein). This fusion protein was used as protein bait for the viral RNA. It was proposed that if RNA interacted with the fusion protein, it would be pulled down by the mass of affinity matrix and be precipitated and fluoresce when analysed by agarose gel electrophoresis using ethidium bromide. Despite optimisation of the in vitro assay, results were affected by the interaction between the intein-tag and nucleic acids, the state of the expressed fusion protein (in particular self-cleavage) and the excessive fluorescence present on the gels. The ADH2-GAPDH yeast expression system was used to investigate the in vivo assembly of p71 containing deletions of either one or both clusters within N terminal domain. It was found that all p71 mutants were expressed with the exception of the mutant containing a deletion of the second cluster. The reasons for this still require further investigation. The expressed p71 mutants were not processed into p64 and were degraded in vivo. In addition, an experimental attempt to purify assembled p71 mutant VLPs was unsuccessful. The assembly defect of p71 mutants emphasised the significance of the clusters, which are possibly required for interaction with viral RNAs for efficient VLP assembly. The results of this study suggest that an alternative tag or in vitro RNA-protein interaction assay be used. In addition, further experiments are required to investigate whether the co-expression of full length viral RNAs are required to rescue the in vivo assembly defect of p71 mutants into VLPs.
- Full Text:
- Date Issued: 2005
Development of experimental systems for studying the biology of Nudaurelia capensis ß virus
- Authors: Walter, Cheryl Tracy
- Date: 2005
- Subjects: Imbrasia cytherea , Insects -- Viruses , RNA viruses , DNA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3948 , http://hdl.handle.net/10962/d1004007 , Imbrasia cytherea , Insects -- Viruses , RNA viruses , DNA
- Description: After 20 years, Nudaurelia ß virus (NßV) was re-isolated from a population of Nudaurelia capensis larvae exhibiting similar symptoms to those described in 1974 for a tetravirus infection. NßV is a member of the Tetraviridae, a family of positive sense insect RNA viruses that exclusively infect Lepidopteran insects. In addition to NbV, there was evidence that the insects were infected with another small RNA virus. SDS-PAGE and Western analysis revealed two proteins (p56 and p58), that cross-reacted with anti-NbV antibodies. Transmission Electron Microscopy (TEM) analysis showed the presence of particles exhibiting a morphology described for NbV and majority of particles of a diameter of 37 nm. In addition there was a second, minor population of particles with a diameter of 34 nm, which also exhibited the characteristic pitted surface of NßV, raising the possibility of two species of NßV in the N. capensis population. To further investigate this, cDNA corresponding to the 3` end of the replicase gene as well as the entire capsid gene of NbV was synthesized and sequenced. Alignments of the cDNA sequence showed a 99.46 % identity to the published sequence of NbV. Two amino acid substitutions were observed in the capsid coding sequence, one of which was a conservative substitution. Both of these substitutions were found in the b-sandwich domain of the capsid protein. Inspection of the capsid coding sequence showed a second methionine (Met50) at the VCAP amino terminus raising the possibility that p56 might arise from a translation product starting at this site. To investigate this, a full length and truncated capsid coding sequence starting at Met50, were expressed in a baculovirus expression system. VLPs were examined by TEM and Western analysis showed the presence of virus like particles with NßV morphology, but smaller in diameter than the wild-type with an average of 33.33 nm, similar to the smaller particles observed in the virus preparations of NßV. This result supported the hypothesis that NßV translates a smaller coat protein from the second in-frame methionine residue.
- Full Text:
- Date Issued: 2005
- Authors: Walter, Cheryl Tracy
- Date: 2005
- Subjects: Imbrasia cytherea , Insects -- Viruses , RNA viruses , DNA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3948 , http://hdl.handle.net/10962/d1004007 , Imbrasia cytherea , Insects -- Viruses , RNA viruses , DNA
- Description: After 20 years, Nudaurelia ß virus (NßV) was re-isolated from a population of Nudaurelia capensis larvae exhibiting similar symptoms to those described in 1974 for a tetravirus infection. NßV is a member of the Tetraviridae, a family of positive sense insect RNA viruses that exclusively infect Lepidopteran insects. In addition to NbV, there was evidence that the insects were infected with another small RNA virus. SDS-PAGE and Western analysis revealed two proteins (p56 and p58), that cross-reacted with anti-NbV antibodies. Transmission Electron Microscopy (TEM) analysis showed the presence of particles exhibiting a morphology described for NbV and majority of particles of a diameter of 37 nm. In addition there was a second, minor population of particles with a diameter of 34 nm, which also exhibited the characteristic pitted surface of NßV, raising the possibility of two species of NßV in the N. capensis population. To further investigate this, cDNA corresponding to the 3` end of the replicase gene as well as the entire capsid gene of NbV was synthesized and sequenced. Alignments of the cDNA sequence showed a 99.46 % identity to the published sequence of NbV. Two amino acid substitutions were observed in the capsid coding sequence, one of which was a conservative substitution. Both of these substitutions were found in the b-sandwich domain of the capsid protein. Inspection of the capsid coding sequence showed a second methionine (Met50) at the VCAP amino terminus raising the possibility that p56 might arise from a translation product starting at this site. To investigate this, a full length and truncated capsid coding sequence starting at Met50, were expressed in a baculovirus expression system. VLPs were examined by TEM and Western analysis showed the presence of virus like particles with NßV morphology, but smaller in diameter than the wild-type with an average of 33.33 nm, similar to the smaller particles observed in the virus preparations of NßV. This result supported the hypothesis that NßV translates a smaller coat protein from the second in-frame methionine residue.
- Full Text:
- Date Issued: 2005
Development of the South African monetary banking sector and money market
- Authors: Patel, Aadil Suleman
- Date: 2005
- Subjects: South African Reserve Bank , Banks and banking -- South Africa , Money market -- South Africa , Economic development -- South Africa , Monetary policy -- South Africa , South Africa -- Economic conditions , Financial institutions -- South Africa , Money -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:997 , http://hdl.handle.net/10962/d1002732 , South African Reserve Bank , Banks and banking -- South Africa , Money market -- South Africa , Economic development -- South Africa , Monetary policy -- South Africa , South Africa -- Economic conditions , Financial institutions -- South Africa , Money -- South Africa
- Description: This thesis presents a theoretical analysis of developments in the South African monetary banking sector and money market. In the first section, evolution of the political, social and economic environments over the past few decades are discussed to provide the reader with an idea of some factors responsible for the underdeveloped nature of this market. It has been argued that the domestic political and economic landscape is relatively stable. Nevertheless, factors such as Zimbabwe’s political and ensuing economic turmoil, coupled with numerous financial crises in other developing nations have had negative consequences on domestic financial market development and economic growth. The current state of monetary policy is also analysed, within the economic environment, and various policy considerations have been put forth concerning the inflation targeting policy. The thesis then goes on to scrutinise the statutory and institutional environments within which the monetary banking institutions operate. Recent changes in the regulations governing the operations of these institutions are identified, together with the consequences of such laws on banking institutions and possible amendments have been suggested. In particular, a system of Asset Based Reserve Requirements (ABRR) has been recommended, in place of the current cash reserve requirement, to ensure regulators create a level playing field in the financial sector. The system can also provide authorities with the necessary control required to direct funds to the most desirable sectors of the economy. Development of the interbank market and the effect of reduced banking competition on the efficacy of the South African Reserve Bank’s refinancing operations and inflation targeting policy are also considered. Finally, the thesis analyses some effects of financial development on the South African economy, and whether it is in the best interests of the country to pursue financial reforms with such vigour. While financial development may bring South Africa closer to international standards of best practice, the timing and extent of the reforms will be critical to guarantee success.
- Full Text:
- Date Issued: 2005
- Authors: Patel, Aadil Suleman
- Date: 2005
- Subjects: South African Reserve Bank , Banks and banking -- South Africa , Money market -- South Africa , Economic development -- South Africa , Monetary policy -- South Africa , South Africa -- Economic conditions , Financial institutions -- South Africa , Money -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:997 , http://hdl.handle.net/10962/d1002732 , South African Reserve Bank , Banks and banking -- South Africa , Money market -- South Africa , Economic development -- South Africa , Monetary policy -- South Africa , South Africa -- Economic conditions , Financial institutions -- South Africa , Money -- South Africa
- Description: This thesis presents a theoretical analysis of developments in the South African monetary banking sector and money market. In the first section, evolution of the political, social and economic environments over the past few decades are discussed to provide the reader with an idea of some factors responsible for the underdeveloped nature of this market. It has been argued that the domestic political and economic landscape is relatively stable. Nevertheless, factors such as Zimbabwe’s political and ensuing economic turmoil, coupled with numerous financial crises in other developing nations have had negative consequences on domestic financial market development and economic growth. The current state of monetary policy is also analysed, within the economic environment, and various policy considerations have been put forth concerning the inflation targeting policy. The thesis then goes on to scrutinise the statutory and institutional environments within which the monetary banking institutions operate. Recent changes in the regulations governing the operations of these institutions are identified, together with the consequences of such laws on banking institutions and possible amendments have been suggested. In particular, a system of Asset Based Reserve Requirements (ABRR) has been recommended, in place of the current cash reserve requirement, to ensure regulators create a level playing field in the financial sector. The system can also provide authorities with the necessary control required to direct funds to the most desirable sectors of the economy. Development of the interbank market and the effect of reduced banking competition on the efficacy of the South African Reserve Bank’s refinancing operations and inflation targeting policy are also considered. Finally, the thesis analyses some effects of financial development on the South African economy, and whether it is in the best interests of the country to pursue financial reforms with such vigour. While financial development may bring South Africa closer to international standards of best practice, the timing and extent of the reforms will be critical to guarantee success.
- Full Text:
- Date Issued: 2005
Discourses surrounding 'race', equity, disadvantage and transformation in times of rapid social change : higher education in post-apartheid South Africa
- Authors: Robus, Donovan
- Date: 2005
- Subjects: Rhodes University , University of Fort Hare , Universities and colleges -- Mergers -- South Africa , Education, Higher -- South Africa , Education and state -- South Africa , Apartheid -- South Africa , Discourse analysis -- Methodology , Discrimination in education -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3142 , http://hdl.handle.net/10962/d1007196 , Rhodes University , University of Fort Hare , Universities and colleges -- Mergers -- South Africa , Education, Higher -- South Africa , Education and state -- South Africa , Apartheid -- South Africa , Discourse analysis -- Methodology , Discrimination in education -- South Africa , Educational change -- South Africa
- Description: Since the dismantling of Apartheid in South Africa in 1994, the South African socio-political and economic landscape has been characterised by rapid change. In the ten years since the 'new' democratic South Africa emerged, transformation has become a dominant discourse that has driven much action and practice in a variety of public areas. One of the areas of focus for transformation has been Higher Education whereby the Department of Education aimed to do away with disparity caused by Apartheid segregation by reducing the number of Higher Education institutions from 36 to 21. This research draws on Foucauldian theory and post-colonial theories (in particular Edward Said and Frantz Fanon), and the concept of racialisation in an analysis of the incorporation of Rhodes University's East London campus into the University of Fort Hare. Ian Parker's discourse analytic approach which suggests that discourses support institutions, reproduce power relations and have ideological effects, was utilised to analyse the talk of students and staff at the three sites affected by the incorporation (viz. Rhodes, Grahamstown, Rhodes, East London and Fort Hare) as well as newspaper articles and public statements made by the two institutions. What emerged was that in post-Apartheid South Africa, institutional and geographic space is still racialised with virtually no reference to the historical and contextual foundations from which this emerged being made. In positioning space and institutions in this racialised manner a discourse of 'white' excellence and 'black' failure emerges with the notion of competence gaining legitimacy through an appeal to academic standards. In addition to this, transformation emerges as a signifier of shifting boundaries in a post-Apartheid society where racialised institutional, spatial and social boundaries evidently still exist discursively.
- Full Text:
- Date Issued: 2005
- Authors: Robus, Donovan
- Date: 2005
- Subjects: Rhodes University , University of Fort Hare , Universities and colleges -- Mergers -- South Africa , Education, Higher -- South Africa , Education and state -- South Africa , Apartheid -- South Africa , Discourse analysis -- Methodology , Discrimination in education -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3142 , http://hdl.handle.net/10962/d1007196 , Rhodes University , University of Fort Hare , Universities and colleges -- Mergers -- South Africa , Education, Higher -- South Africa , Education and state -- South Africa , Apartheid -- South Africa , Discourse analysis -- Methodology , Discrimination in education -- South Africa , Educational change -- South Africa
- Description: Since the dismantling of Apartheid in South Africa in 1994, the South African socio-political and economic landscape has been characterised by rapid change. In the ten years since the 'new' democratic South Africa emerged, transformation has become a dominant discourse that has driven much action and practice in a variety of public areas. One of the areas of focus for transformation has been Higher Education whereby the Department of Education aimed to do away with disparity caused by Apartheid segregation by reducing the number of Higher Education institutions from 36 to 21. This research draws on Foucauldian theory and post-colonial theories (in particular Edward Said and Frantz Fanon), and the concept of racialisation in an analysis of the incorporation of Rhodes University's East London campus into the University of Fort Hare. Ian Parker's discourse analytic approach which suggests that discourses support institutions, reproduce power relations and have ideological effects, was utilised to analyse the talk of students and staff at the three sites affected by the incorporation (viz. Rhodes, Grahamstown, Rhodes, East London and Fort Hare) as well as newspaper articles and public statements made by the two institutions. What emerged was that in post-Apartheid South Africa, institutional and geographic space is still racialised with virtually no reference to the historical and contextual foundations from which this emerged being made. In positioning space and institutions in this racialised manner a discourse of 'white' excellence and 'black' failure emerges with the notion of competence gaining legitimacy through an appeal to academic standards. In addition to this, transformation emerges as a signifier of shifting boundaries in a post-Apartheid society where racialised institutional, spatial and social boundaries evidently still exist discursively.
- Full Text:
- Date Issued: 2005
Effective management of an information technology professional's career
- Authors: Tedder, Derek
- Date: 2005
- Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
- Full Text:
- Date Issued: 2005
- Authors: Tedder, Derek
- Date: 2005
- Subjects: Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1148 , http://hdl.handle.net/10962/d1004543 , Information technology -- Vocational guidance , Information technology -- Management , Knowledge management , Career development , Computer Science -- Vocational guidance , System analysis -- Vocational guidance
- Description: The human resource is constantly cited as an organisation's greatest asset. In a rapidly changing technological environment this is most applicable to the Information Technology (IT) function. Organisations are experiencing IT human resource problems such as low satisfaction, early plateauing, high turnover, burnout, limited advancement potential, nominal corporate commitment, supervisory aversion, poor organisational culture, and exceptional compensation. These problems are directly related to the IT professional's career. There is a lack of information and awareness surrounding IT careers to deal effectively with these problems. The research aims to create increased awareness of IT careers and the inherent problems through the development of a career management model. The research aims to identify the factors that influence IT careers, provide career management with a means to measure compatibility of the factors, and suggest solutions to incompatibility. The solving of this problem will be of mutual benefit to both organisations and individuals as they seek to better manage IT careers. After reviewing research literature relating to career anchors, IT job types, IT skills portfolios, and career dynamics a model for Effective IT Career Management (EITCM) has been constructed. The model represents the dynamic interactions between individual, organisational, and dependent factors. The model examines the compatibility of these interacting factors by measuring the levels of relevant career variables. The model suggests appropriate career management techniques to increase the compatibility of the interacting factors. An empirical study was designed and launched online to provide data that would confirm the seven Critical Success Factors (CSF) relating to the proposed model. The responses from the members of the Computer Society of South Africa (CSSA) allowed the seven hypotheses derived from the CSFs to be tested. The results of the empirical study were positive but required modification to five of the CSFs before they could be confirmed. The EITCM model was modified to reflect the improved CSFs. An awareness of career influencing factors combined with active career management is advantageous to both IT professionals and their organisations.
- Full Text:
- Date Issued: 2005
Enabling reflexivity and the development of reflexive competence within course processes: a case study of an environmental education professional development course
- Authors: Raven, Glenda C
- Date: 2005
- Subjects: Rhodes University / Gold Fields Course in Environmental Education Environmental education -- Research -- South Africa Environmental education -- South Africa -- Curricula Competency-based education -- South Africa Education and state -- South Africa Education -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1507 , http://hdl.handle.net/10962/d1003389
- Description: This research was undertaken in the context of socio-economic transformation in South Africa, and more specifically, in the context of change in education policy. To support socio-economic transformation in South Africa after the first democratic elections in 1994, a competence-based National Qualifications Framework (NQF) was introduced in 1995. In responding to the particular socio-historical context of South Africa, the South African NQF is underpinned by the notion of applied competence, integrating practical, foundational and reflexive competence, which is the key and distinguishing feature of this competence-based framework. In this context of transformation, the research was aimed at an in-depth exploration of the notion of reflexivity and reflexive competence, and course processes that enable its development, with a view to providing curriculum development insights for learning programme development in the competence-based NQF, more broadly, and environmental education professional development programmes, more specifically. To enable these aims, the research was undertaken in the context of the Rhodes University / Gold Fields Participatory Course in Environmental Education (RU/GF course), as a case example of a professional development course that aims to develop critically reflexive practitioners. Within an interpretivist orientation, a multiple-embedded case study approach was used to gain insight into the relationship between course processes, reflexivity and the development of reflexive competence to clarify and provide a critical perspective on how competence develops in the context of the course. Data was collected over a period of one year using observation, interviewing and document analysis as the primary data collection techniques. Data was analysed through various phases and layers to inform data generation and the synthesising of data for further interpretation. Through the literature review undertaken within the study, various significant insights emerged around the notion of reflexivity and reflexive competence. Firstly, there appears to be a need to distinguish between reflexivity as social processes of change (social actions and interactions within social systems, structures and processes) and reflexive competence (a range of integrative elements of competence) that provides the evidence of an engagement within social processes of change. The second key insight emerging is the significance of social structure in shaping participation in reflexive processes, thus emphasising the duality of structure as both the medium for, and outcome of reflexive social actions and interactions and so challenges the deterministic conception of social structure. Further, the significance of an epistemologically framed notion of reflexivity and reflexive competence emerged, in the context of responding to the complex and uncertain quality of socio-ecological risks and in supporting change in context. Reflexivity, distinguished from processes of critical reflection, foregrounds a critical exploration of both knowledge and unawareness. As such a reinterpretation of reflexive competence is offered as a process of potential challenge to dominant and reigning forms of reasoning (knowledge frameworks) and consequent principles of ordering. Through this reframing of reflexive competence, the potential exists to destabilise dominant forms of reasoning and principles of ordering to create a broader scope of possibilities for action and change in context. This reframing of reflexive competence in the context of transformation in South Africa has critical implications for engaging within processes of learning programme design in the NQF to support an engagement within reflexive processes of change and the development of a range of integrative elements of reflexive competence. In this light, the study attempts to make the following contribution to curriculum deliberations within the context of environmental education and the NQF in relation to reflexivity, reflexive competence and change: ♦ Reflexivity is conceptualised as social processes of change with reflexive competence providing evidence of engagement within these social processes of change; ♦ An epistemologically framed conception of reflexivity and reflexive competence recognises how rules of reason and the ordering of the ‘reasonable’ person come to shape social life; and so ♦ Change is conceptualised as ruptures and breaks in dominant knowledge frames and the power relations embedded in these; ♦ Unawareness emerges as a key dimension within reflexive environmental education processes in responding to the unpredictable and uncertain nature of risks; ♦ An epistemological framing of reflexivity and reflexive competence highlights the need to develop open processes of learning to support the critical exploration of knowledge and unawareness; and ♦ Within this framing of reflexivity and reflexive competence, the difficulty emerges in specifically predefining reflexive competence to inform standard setting processes within a context of intended change. In framing data within this emerging conception of reflexivity and reflexive competence, a review of course processes highlighted potential areas for reorienting the RU/GF course to support change in context, for which I make specific recommendations. Drawing on the review of course processes in the RU/GF course, and in light of the reframing of reflexivity and reflexive competence, I further offer summative discussions as ‘possible implications’ for learning programme design in the South African competence-based NQF, broadly and environmental education professional development programmes in this framework, more specifically.
- Full Text:
- Date Issued: 2005
- Authors: Raven, Glenda C
- Date: 2005
- Subjects: Rhodes University / Gold Fields Course in Environmental Education Environmental education -- Research -- South Africa Environmental education -- South Africa -- Curricula Competency-based education -- South Africa Education and state -- South Africa Education -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1507 , http://hdl.handle.net/10962/d1003389
- Description: This research was undertaken in the context of socio-economic transformation in South Africa, and more specifically, in the context of change in education policy. To support socio-economic transformation in South Africa after the first democratic elections in 1994, a competence-based National Qualifications Framework (NQF) was introduced in 1995. In responding to the particular socio-historical context of South Africa, the South African NQF is underpinned by the notion of applied competence, integrating practical, foundational and reflexive competence, which is the key and distinguishing feature of this competence-based framework. In this context of transformation, the research was aimed at an in-depth exploration of the notion of reflexivity and reflexive competence, and course processes that enable its development, with a view to providing curriculum development insights for learning programme development in the competence-based NQF, more broadly, and environmental education professional development programmes, more specifically. To enable these aims, the research was undertaken in the context of the Rhodes University / Gold Fields Participatory Course in Environmental Education (RU/GF course), as a case example of a professional development course that aims to develop critically reflexive practitioners. Within an interpretivist orientation, a multiple-embedded case study approach was used to gain insight into the relationship between course processes, reflexivity and the development of reflexive competence to clarify and provide a critical perspective on how competence develops in the context of the course. Data was collected over a period of one year using observation, interviewing and document analysis as the primary data collection techniques. Data was analysed through various phases and layers to inform data generation and the synthesising of data for further interpretation. Through the literature review undertaken within the study, various significant insights emerged around the notion of reflexivity and reflexive competence. Firstly, there appears to be a need to distinguish between reflexivity as social processes of change (social actions and interactions within social systems, structures and processes) and reflexive competence (a range of integrative elements of competence) that provides the evidence of an engagement within social processes of change. The second key insight emerging is the significance of social structure in shaping participation in reflexive processes, thus emphasising the duality of structure as both the medium for, and outcome of reflexive social actions and interactions and so challenges the deterministic conception of social structure. Further, the significance of an epistemologically framed notion of reflexivity and reflexive competence emerged, in the context of responding to the complex and uncertain quality of socio-ecological risks and in supporting change in context. Reflexivity, distinguished from processes of critical reflection, foregrounds a critical exploration of both knowledge and unawareness. As such a reinterpretation of reflexive competence is offered as a process of potential challenge to dominant and reigning forms of reasoning (knowledge frameworks) and consequent principles of ordering. Through this reframing of reflexive competence, the potential exists to destabilise dominant forms of reasoning and principles of ordering to create a broader scope of possibilities for action and change in context. This reframing of reflexive competence in the context of transformation in South Africa has critical implications for engaging within processes of learning programme design in the NQF to support an engagement within reflexive processes of change and the development of a range of integrative elements of reflexive competence. In this light, the study attempts to make the following contribution to curriculum deliberations within the context of environmental education and the NQF in relation to reflexivity, reflexive competence and change: ♦ Reflexivity is conceptualised as social processes of change with reflexive competence providing evidence of engagement within these social processes of change; ♦ An epistemologically framed conception of reflexivity and reflexive competence recognises how rules of reason and the ordering of the ‘reasonable’ person come to shape social life; and so ♦ Change is conceptualised as ruptures and breaks in dominant knowledge frames and the power relations embedded in these; ♦ Unawareness emerges as a key dimension within reflexive environmental education processes in responding to the unpredictable and uncertain nature of risks; ♦ An epistemological framing of reflexivity and reflexive competence highlights the need to develop open processes of learning to support the critical exploration of knowledge and unawareness; and ♦ Within this framing of reflexivity and reflexive competence, the difficulty emerges in specifically predefining reflexive competence to inform standard setting processes within a context of intended change. In framing data within this emerging conception of reflexivity and reflexive competence, a review of course processes highlighted potential areas for reorienting the RU/GF course to support change in context, for which I make specific recommendations. Drawing on the review of course processes in the RU/GF course, and in light of the reframing of reflexivity and reflexive competence, I further offer summative discussions as ‘possible implications’ for learning programme design in the South African competence-based NQF, broadly and environmental education professional development programmes in this framework, more specifically.
- Full Text:
- Date Issued: 2005
Enzymatic recovery of rhodium(III) from aqueous solution and industrial effluent using sulphate reducing bacteria: role of a hydrogenase enzyme
- Authors: Ngwenya, Nonhlanhla
- Date: 2005
- Subjects: Enzymes , Rhodium , Enzymes -- Industrial applications , Sulfur bacteria , Hydrogenation , Hydragenase , Factory and trade waste -- Purification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3956 , http://hdl.handle.net/10962/d1004015 , Enzymes , Rhodium , Enzymes -- Industrial applications , Sulfur bacteria , Hydrogenation , Hydragenase , Factory and trade waste -- Purification
- Description: In an attempt to overcome the high maintenance and costs associated with traditional physico-chemical methods, much work is being done on the application of enzymes for the recovery of valuable metals from solutions and industrial effluents. One of the most widely studied enzymatic metal recovery systems uses hydrogenase enzymes, particularly from sulphate reducing bacteria (SRB). While it is known that hydrogenases from SRB mediate the reductive precipitation of metals, the mechanism of enzymatic reduction, however, is not yet fully understood. The main aim of the present study was to investigate the role of a hydrogenase enzyme in the removal of rhodium from both aqueous solution and industrial effluent. A quantitative analysis of the rate of removal of rhodium(III) by a resting SRB consortium under different initial rhodium and biomass concentrations, pH, temperature, presence and absence of SRB cells and electron donor, was studied. Rhodium speciation was found to be the main factor controlling the rate of removal of rhodium from solution. SRB cells were found to have a higher affinity for anionic rhodium species, as compared to both cationic and neutral species, which become abundant when speciation equilibrium was reached. Consequently, a pH-dependant rate of rhodium removal from solution was observed. The maximum SRB uptake capacity for rhodium was found to be 66 mg rhodium per g of resting SRB biomass. Electron microscopy studies revealed a time-dependant localization and distribution of rhodium precipitates, initially intracellularly and then extracellularly, suggesting the involvement of an enzymatic reductive precipitation process. A hydrogenase enzyme capable of reducing rhodium(III) from solution was isolated and purified by PEG, DEAE-Sephacel anion exchanger and Sephadex G200 gel exclusion. A distinct protein band with a molecular weight of 62kDa was obtained when the hydrogenase containing fractions were subjected to a 10% SDS-PAGE. Characterization studies indicated that the purified hydrogenase had an optimum pH and temperature of 8 and 40°C, respectively. A maximum of 88% of the initial rhodium in solution was removed when the purified hydrogenase was incubated under hydrogen. Due to the low pH of the industrial effluent (1.31), the enzymatic reduction of rhodium by the purified hydrogenase was greatly retarded. It was apparent that industrial effluent pretreatment was necessary before the application an enzymatic treatment method. In the present study, however, it has been established that SRB are good candidates for the enzymatic recovery of rhodium from both solution and effluent.
- Full Text:
- Date Issued: 2005
- Authors: Ngwenya, Nonhlanhla
- Date: 2005
- Subjects: Enzymes , Rhodium , Enzymes -- Industrial applications , Sulfur bacteria , Hydrogenation , Hydragenase , Factory and trade waste -- Purification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3956 , http://hdl.handle.net/10962/d1004015 , Enzymes , Rhodium , Enzymes -- Industrial applications , Sulfur bacteria , Hydrogenation , Hydragenase , Factory and trade waste -- Purification
- Description: In an attempt to overcome the high maintenance and costs associated with traditional physico-chemical methods, much work is being done on the application of enzymes for the recovery of valuable metals from solutions and industrial effluents. One of the most widely studied enzymatic metal recovery systems uses hydrogenase enzymes, particularly from sulphate reducing bacteria (SRB). While it is known that hydrogenases from SRB mediate the reductive precipitation of metals, the mechanism of enzymatic reduction, however, is not yet fully understood. The main aim of the present study was to investigate the role of a hydrogenase enzyme in the removal of rhodium from both aqueous solution and industrial effluent. A quantitative analysis of the rate of removal of rhodium(III) by a resting SRB consortium under different initial rhodium and biomass concentrations, pH, temperature, presence and absence of SRB cells and electron donor, was studied. Rhodium speciation was found to be the main factor controlling the rate of removal of rhodium from solution. SRB cells were found to have a higher affinity for anionic rhodium species, as compared to both cationic and neutral species, which become abundant when speciation equilibrium was reached. Consequently, a pH-dependant rate of rhodium removal from solution was observed. The maximum SRB uptake capacity for rhodium was found to be 66 mg rhodium per g of resting SRB biomass. Electron microscopy studies revealed a time-dependant localization and distribution of rhodium precipitates, initially intracellularly and then extracellularly, suggesting the involvement of an enzymatic reductive precipitation process. A hydrogenase enzyme capable of reducing rhodium(III) from solution was isolated and purified by PEG, DEAE-Sephacel anion exchanger and Sephadex G200 gel exclusion. A distinct protein band with a molecular weight of 62kDa was obtained when the hydrogenase containing fractions were subjected to a 10% SDS-PAGE. Characterization studies indicated that the purified hydrogenase had an optimum pH and temperature of 8 and 40°C, respectively. A maximum of 88% of the initial rhodium in solution was removed when the purified hydrogenase was incubated under hydrogen. Due to the low pH of the industrial effluent (1.31), the enzymatic reduction of rhodium by the purified hydrogenase was greatly retarded. It was apparent that industrial effluent pretreatment was necessary before the application an enzymatic treatment method. In the present study, however, it has been established that SRB are good candidates for the enzymatic recovery of rhodium from both solution and effluent.
- Full Text:
- Date Issued: 2005
Establishment and impact of the sap-sucking mirid, Falconia intermedia (Distant) (Hemiptera: Miridae) on Lantana camara (Verbenaceae) varieties in the Eastern Cape Province, South Africa
- Heshula, Unathi-Nkosi Lelethu Peter
- Authors: Heshula, Unathi-Nkosi Lelethu Peter
- Date: 2005
- Subjects: Lantana camara -- South Africa -- Eastern Cape , Biological pest control agents -- South Africa -- Eastern Cape , Hemiptera -- South Africa -- Eastern Cape , Miridae -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5832 , http://hdl.handle.net/10962/d1008085
- Description: The biological control of the weedy complex Lantana camara (L.) (Verbenaceae) has been ongoing in South Africa for over 40 years. Despite this, the weed is still not under sufficient control and continues to invade new territories in the country. The biological control programme needs to be bolstered with releases of new and potentially damaging biological control agents. A promising biological control agent endemic to Central America, Falconia intermedia (Distant) (Hemiptera: Miridae), was imported into quarantine from Jamaica in 1994. This agent was released on sites in KwaZulu-Natal and Limpopo provinces of South Africa in 1999. Even though it initially established and damaged L. camara, populations died out at most of the release sites. As varietal difference and adverse climate have been cited as the reason for non-establishment and ineffective control in L. camara biocontrol programmes worldwide, this study attempts to investigate the role that these two factors play in this weed herbivore relationship. Laboratory no-choice trials were conducted to determine the varietal performance of F intermedia, among five Eastern Cape varieties of the weed from East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm, and a variety from the Plant Protection Research Institute (PPRI), Pretoria. However, there were differences in performance as the adult mirids performed better on white-pink varieties from Whitney Farm and Heather Glen Farm. To test varietal preference in field conditions, field releases of F intermedia were also made at East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm. Post release evaluations were conducted monthly for two years (2002 and 2003). The insect established at East London and Whitney Farm, both of which have white-pink varieties. Insect populations quickly died out at the Lyndhurst Farm and Port Alfred sites, which have dark pink varieties. It is suggested that field conditions may have resulted in poor plant quality and led indirectly to varietal preference, and to non-establishment at these two sites. With the onset of cooler weather, populations disappeared at Heather Glen Farm. This suggested that F. intermedia was suitable for release in more subtropical areas within South Africa where climatic conditions would be suitable throughout the year. The mirid performed well at Whitney Farm, resulting in significant reduction in plant growth parameters such as height and percentage cover, and increasing the cover of other flora growing beneath L. camara plants. Finally, ways to improve the efficacy of this agent are considered in an effort towards better control of L. camara in South Africa.
- Full Text:
- Date Issued: 2005
- Authors: Heshula, Unathi-Nkosi Lelethu Peter
- Date: 2005
- Subjects: Lantana camara -- South Africa -- Eastern Cape , Biological pest control agents -- South Africa -- Eastern Cape , Hemiptera -- South Africa -- Eastern Cape , Miridae -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5832 , http://hdl.handle.net/10962/d1008085
- Description: The biological control of the weedy complex Lantana camara (L.) (Verbenaceae) has been ongoing in South Africa for over 40 years. Despite this, the weed is still not under sufficient control and continues to invade new territories in the country. The biological control programme needs to be bolstered with releases of new and potentially damaging biological control agents. A promising biological control agent endemic to Central America, Falconia intermedia (Distant) (Hemiptera: Miridae), was imported into quarantine from Jamaica in 1994. This agent was released on sites in KwaZulu-Natal and Limpopo provinces of South Africa in 1999. Even though it initially established and damaged L. camara, populations died out at most of the release sites. As varietal difference and adverse climate have been cited as the reason for non-establishment and ineffective control in L. camara biocontrol programmes worldwide, this study attempts to investigate the role that these two factors play in this weed herbivore relationship. Laboratory no-choice trials were conducted to determine the varietal performance of F intermedia, among five Eastern Cape varieties of the weed from East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm, and a variety from the Plant Protection Research Institute (PPRI), Pretoria. However, there were differences in performance as the adult mirids performed better on white-pink varieties from Whitney Farm and Heather Glen Farm. To test varietal preference in field conditions, field releases of F intermedia were also made at East London, Whitney Farm, Heather Glen Farm, Port Alfred and Lyndhurst Farm. Post release evaluations were conducted monthly for two years (2002 and 2003). The insect established at East London and Whitney Farm, both of which have white-pink varieties. Insect populations quickly died out at the Lyndhurst Farm and Port Alfred sites, which have dark pink varieties. It is suggested that field conditions may have resulted in poor plant quality and led indirectly to varietal preference, and to non-establishment at these two sites. With the onset of cooler weather, populations disappeared at Heather Glen Farm. This suggested that F. intermedia was suitable for release in more subtropical areas within South Africa where climatic conditions would be suitable throughout the year. The mirid performed well at Whitney Farm, resulting in significant reduction in plant growth parameters such as height and percentage cover, and increasing the cover of other flora growing beneath L. camara plants. Finally, ways to improve the efficacy of this agent are considered in an effort towards better control of L. camara in South Africa.
- Full Text:
- Date Issued: 2005
Euphausiid population structure and grazing in the Indian sector of the Antarctic Polar Frontal Zone, during austral autumn
- Bernard, Anthony Thomas Firth
- Authors: Bernard, Anthony Thomas Firth
- Date: 2005
- Subjects: Euphausiacea -- Antarctic Ocean , Euphausiacea -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5913 , http://hdl.handle.net/10962/d1015960
- Description: The trophodynamics of the numerically dominant euphausiid species within a region of high mesoscale oceanographic variability in the southwest Indian sector of the Antarctic Polar Frontal Zone (PFZ) were investigated during the austral autumns April/May) of 2004 and 2005. During the 2004 survey, sub-surface (200 m) temperature profiles indicated that an intense frontal feature, formed by the convergence of the Sub-Antarctic Front (SAF) and the Antarctic Polar Front (APF) bisected the survey area into two distinct zones, the Sub- Antarctic Zone (SAZ) and the Antarctic Zone (AAZ). Total integrated chlorophyll-a (chl-a) biomass was typical for the region (< 25 mg chl-a m⁻²), and was dominated by picophytoplankton. Total euphausiid abundance and biomass ranged from 0.1 to 3.1 ind m⁻³ and 0.1 to 8.1 mg dwt m⁻³, respectively, and did not differ significantly between the stations occupied in the SAZ and AAZ (p > 0.05). The multivariate analysis identified two interacting mechanisms controlling the distribution patterns, abundance and biomass of the various euphausiid species, namely (1) diel changes in abundance and biomass, (2) and restricted distribution patterns associated with the different water masses. Ingestion rates were determined for five euphausiid species. E. triacantha was found to have the highest daily ingestion rate ranging from 1 226.1 to 6 029.1 ng pigm ind⁻¹d⁻¹, while the lowest daily ingestion rates were observed in the juvenile Thysanoessa species (6.4 to 943.0 ng pigm ind⁻¹ d⁻¹). The total grazing impact of the selected euphausiids ranged from < 0.1 to 20.1 μg pigm m⁻²d⁻¹, corresponding to < 0.15 % of the areal chl-a biomass. The daily ration estimates of autotrophic carbon for the euphausiids suggested that phytoplankton represented a minor component in their diets, with only the sub-adult E. vallentini consuming sufficient phytoplankton to meet their daily carbon requirements. A cyclonic cold-core eddy spawned from the region of the APF located in the southwest Indian sector of the PFZ was the dominant feature during the 2005 survey. The total areal chl-a biomass throughout the region was low, ranging between 5.6 and 11.4 mg chl-a m⁻², and was significantly higher within the core of the eddy compared to the surrounding waters (p < 0.05). RMT-8 and WP-2 total euphausiid abundance and biomass estimates were high, and ranged from 0.004 to 0.36 ind m⁻³ and 0.065 to 1.21 mg dwt m⁻³, and from 0.01 to 18.2 ind m⁻³ and 0.01 to 15.7 mg dwt m⁻³, respectively. A distinct spatial pattern in the euphausiid community was evident with the Antarctic species, Euphausia frigida, E. triacantha and E. superba predominating within the core of the eddy, while the PFZ waters were characterized by the sub-Antarctic species, E. longirostris, Stylocheiron maximum, Nematoscelis megalops and Thysanoessa gregaria. The eddy edge acted as a transition zone where species from both regions co-occurred. Within the survey area the combined ingestion rate of the six numerically dominant euphausiid species ranged between 0.02 and 5.31 μg pigm m⁻²d¹, which corresponded to a loss of between < 0.001 and 0.11 % of the available chl-a biomass. E. triacantha and juvenile T. macura were identified as the dominant grazers. There was no apparent spatial pattern in the grazing activity of the euphausiids within the region of investigation. The average daily rations of the euphausiids examined were < 2 % of their body carbon. The low daily ration of the euphausiids could be ascribed to the predominance of small picophytoplankton in the region of investigation, which are too small to be grazed efficiently by larger zooplankton. The marked spatial patterns in species composition and the elevated abundance and biomass of euphausiids, suggest that the mesoscale eddies contribute to the spatial and temporal heterogeneity of the planktonic community of the PFZ and may represent important foraging regions for many of the apex predators within the region.
- Full Text:
- Date Issued: 2005
- Authors: Bernard, Anthony Thomas Firth
- Date: 2005
- Subjects: Euphausiacea -- Antarctic Ocean , Euphausiacea -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5913 , http://hdl.handle.net/10962/d1015960
- Description: The trophodynamics of the numerically dominant euphausiid species within a region of high mesoscale oceanographic variability in the southwest Indian sector of the Antarctic Polar Frontal Zone (PFZ) were investigated during the austral autumns April/May) of 2004 and 2005. During the 2004 survey, sub-surface (200 m) temperature profiles indicated that an intense frontal feature, formed by the convergence of the Sub-Antarctic Front (SAF) and the Antarctic Polar Front (APF) bisected the survey area into two distinct zones, the Sub- Antarctic Zone (SAZ) and the Antarctic Zone (AAZ). Total integrated chlorophyll-a (chl-a) biomass was typical for the region (< 25 mg chl-a m⁻²), and was dominated by picophytoplankton. Total euphausiid abundance and biomass ranged from 0.1 to 3.1 ind m⁻³ and 0.1 to 8.1 mg dwt m⁻³, respectively, and did not differ significantly between the stations occupied in the SAZ and AAZ (p > 0.05). The multivariate analysis identified two interacting mechanisms controlling the distribution patterns, abundance and biomass of the various euphausiid species, namely (1) diel changes in abundance and biomass, (2) and restricted distribution patterns associated with the different water masses. Ingestion rates were determined for five euphausiid species. E. triacantha was found to have the highest daily ingestion rate ranging from 1 226.1 to 6 029.1 ng pigm ind⁻¹d⁻¹, while the lowest daily ingestion rates were observed in the juvenile Thysanoessa species (6.4 to 943.0 ng pigm ind⁻¹ d⁻¹). The total grazing impact of the selected euphausiids ranged from < 0.1 to 20.1 μg pigm m⁻²d⁻¹, corresponding to < 0.15 % of the areal chl-a biomass. The daily ration estimates of autotrophic carbon for the euphausiids suggested that phytoplankton represented a minor component in their diets, with only the sub-adult E. vallentini consuming sufficient phytoplankton to meet their daily carbon requirements. A cyclonic cold-core eddy spawned from the region of the APF located in the southwest Indian sector of the PFZ was the dominant feature during the 2005 survey. The total areal chl-a biomass throughout the region was low, ranging between 5.6 and 11.4 mg chl-a m⁻², and was significantly higher within the core of the eddy compared to the surrounding waters (p < 0.05). RMT-8 and WP-2 total euphausiid abundance and biomass estimates were high, and ranged from 0.004 to 0.36 ind m⁻³ and 0.065 to 1.21 mg dwt m⁻³, and from 0.01 to 18.2 ind m⁻³ and 0.01 to 15.7 mg dwt m⁻³, respectively. A distinct spatial pattern in the euphausiid community was evident with the Antarctic species, Euphausia frigida, E. triacantha and E. superba predominating within the core of the eddy, while the PFZ waters were characterized by the sub-Antarctic species, E. longirostris, Stylocheiron maximum, Nematoscelis megalops and Thysanoessa gregaria. The eddy edge acted as a transition zone where species from both regions co-occurred. Within the survey area the combined ingestion rate of the six numerically dominant euphausiid species ranged between 0.02 and 5.31 μg pigm m⁻²d¹, which corresponded to a loss of between < 0.001 and 0.11 % of the available chl-a biomass. E. triacantha and juvenile T. macura were identified as the dominant grazers. There was no apparent spatial pattern in the grazing activity of the euphausiids within the region of investigation. The average daily rations of the euphausiids examined were < 2 % of their body carbon. The low daily ration of the euphausiids could be ascribed to the predominance of small picophytoplankton in the region of investigation, which are too small to be grazed efficiently by larger zooplankton. The marked spatial patterns in species composition and the elevated abundance and biomass of euphausiids, suggest that the mesoscale eddies contribute to the spatial and temporal heterogeneity of the planktonic community of the PFZ and may represent important foraging regions for many of the apex predators within the region.
- Full Text:
- Date Issued: 2005
Exploring learners' mathematical understanding through an analysis of their solution strategies
- Authors: Penlington, Thomas Helm
- Date: 2005
- Subjects: Mathematics -- Study and teaching (Elementary) Mathematics -- Problems, exercises, etc. Problem solving -- Study and teaching Reasoning Mathematical ability
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1934 , http://hdl.handle.net/10962/d1007642
- Description: The purpose of this study is to investigate various solution strategies employed by Grade 7 learners and their teachers when solving a given set of mathematical tasks. This study is oriented in an interpretive paradigm and is characterised by qualitative methods. The research, set in nine schools in the Eastern Cape, was carried out with nine learners and their mathematics teachers and was designed around two phases. The research tools consisted of a set of 12 tasks that were modelled after the Third International Mathematics and Science Study (TIMSS), and a process of clinical interviews that interrogated the solution strategies that were used in solving the 12 tasks. Aspects of grounded theory were used in the analysis of the data. The study reveals that in most tasks, learners relied heavily on procedural understanding at the expense of conceptual understanding. It also emphasises that the solution strategies adopted by learners, particularly whole number operations, were consistent with those strategies used by their teachers. Both learners and teachers favoured using the traditional, standard algorithm strategies and appeared to have learned these algorithms in isolation from concepts, failing to relate them to understanding. Another important finding was that there was evidence to suggest that some learners and teachers did employ their own constructed solution strategies. They were able to make sense of the problems and to 'mathematize' effectively and reason mathematically. An interesting outcome of the study shows that participants were more proficient in solving word problems than mathematical computations. This is in contrast to existing research on word problems, where it is shown that teachers find them difficult to teach and learners find them difficult to understand. The findings of this study also highlight issues for mathematics teachers to consider when dealing with computations and word problems involving number sense and other problem solving type problems.
- Full Text:
- Date Issued: 2005
- Authors: Penlington, Thomas Helm
- Date: 2005
- Subjects: Mathematics -- Study and teaching (Elementary) Mathematics -- Problems, exercises, etc. Problem solving -- Study and teaching Reasoning Mathematical ability
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1934 , http://hdl.handle.net/10962/d1007642
- Description: The purpose of this study is to investigate various solution strategies employed by Grade 7 learners and their teachers when solving a given set of mathematical tasks. This study is oriented in an interpretive paradigm and is characterised by qualitative methods. The research, set in nine schools in the Eastern Cape, was carried out with nine learners and their mathematics teachers and was designed around two phases. The research tools consisted of a set of 12 tasks that were modelled after the Third International Mathematics and Science Study (TIMSS), and a process of clinical interviews that interrogated the solution strategies that were used in solving the 12 tasks. Aspects of grounded theory were used in the analysis of the data. The study reveals that in most tasks, learners relied heavily on procedural understanding at the expense of conceptual understanding. It also emphasises that the solution strategies adopted by learners, particularly whole number operations, were consistent with those strategies used by their teachers. Both learners and teachers favoured using the traditional, standard algorithm strategies and appeared to have learned these algorithms in isolation from concepts, failing to relate them to understanding. Another important finding was that there was evidence to suggest that some learners and teachers did employ their own constructed solution strategies. They were able to make sense of the problems and to 'mathematize' effectively and reason mathematically. An interesting outcome of the study shows that participants were more proficient in solving word problems than mathematical computations. This is in contrast to existing research on word problems, where it is shown that teachers find them difficult to teach and learners find them difficult to understand. The findings of this study also highlight issues for mathematics teachers to consider when dealing with computations and word problems involving number sense and other problem solving type problems.
- Full Text:
- Date Issued: 2005