Synthetic approaches to marine labdane diterpenes
- Authors: Wisch, Gregory Albert
- Date: 2002 , 2013-05-10
- Subjects: Diterpenes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4289 , http://hdl.handle.net/10962/d1003131 , Diterpenes
- Description: The work presented in this thesis describes the synthesis of labd-13-en-8ß, 15-diol (46) a stable reduced derivative of an unstable marine natural product aldehyde [8ß-hydroxylabd-13E-en-15-al (6)] isolated by Cimino, et al. from the skin of a Notaspidean mollusc Pleurobranchaea meckelii. The rationale for the synthesis was to provide sufficient 46 for eventual mild oxidation to 6 and investigation of the biological activity of this latter compound. (-)-Sclareol (32), a common diterpene synthetic precursor, was the starting point for the ten step synthesis of 46 described in this thesis. A search of the literature revealed that only one non stereospecific synthesis of 46 had been previously reported. To provide the necessary background to the synthetic component of this thesis, both the occurrence of labdane and ent-labdane in the marine environment and the use of sclareol in the synthesis of marine natural products, was reviewed. The initial step in the synthesis of 46 was the potassium permanganate oxidation of sclareol to give a bisnorlabdane ketone. Reduction of this ketone with lithium aluminium hydride produced a mixture of diols which, through t-butyldimethysilyl triflate protection, afforded a quantitative route to protecting the C-13 ketone in an effort to prevent unwanted intramolecular cyclization reactions. Dehydration of the tertiary alcohol moiety at C-8 with phosphorous oxychloride yielded the Δ⁸·¹⁵ exocyclic alkene required for the next oxidation step. Ozonolysis succeeded in producing the desired C-8 ketone after much deliberation and research into alternative oxidation strategies. Methyl lithium methylation quantitatively afforded the desired a-methyl substitution at C-8, identified at the onset as the key step in the synthesis. Tetra-butylarnmonium fluoride deprotection yielded the 8ß,13-dihydoxylated product, which was in turn subjected to a Swern oxidition to give the desired 8ß-hydroxy-bisnorlabda-13-one. A modified Horner-Wadsworth-Emmons reaction allowed for elaboration at C-13 to yield a to Δ¹³ olefin with a terminal C-15 ethyl ester. Diisobutylaluminium hydride reduction of the ester produced the desired labd-13-en-8ß, 15-diol (46) in a low overall yield of 3.4%. Although opportunities for optimization of at least three steps in the synthesis exist, time constraints prevented both optimization of these steps and an investigation of the oxidation of 46 to 6. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2002
- Authors: Wisch, Gregory Albert
- Date: 2002 , 2013-05-10
- Subjects: Diterpenes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4289 , http://hdl.handle.net/10962/d1003131 , Diterpenes
- Description: The work presented in this thesis describes the synthesis of labd-13-en-8ß, 15-diol (46) a stable reduced derivative of an unstable marine natural product aldehyde [8ß-hydroxylabd-13E-en-15-al (6)] isolated by Cimino, et al. from the skin of a Notaspidean mollusc Pleurobranchaea meckelii. The rationale for the synthesis was to provide sufficient 46 for eventual mild oxidation to 6 and investigation of the biological activity of this latter compound. (-)-Sclareol (32), a common diterpene synthetic precursor, was the starting point for the ten step synthesis of 46 described in this thesis. A search of the literature revealed that only one non stereospecific synthesis of 46 had been previously reported. To provide the necessary background to the synthetic component of this thesis, both the occurrence of labdane and ent-labdane in the marine environment and the use of sclareol in the synthesis of marine natural products, was reviewed. The initial step in the synthesis of 46 was the potassium permanganate oxidation of sclareol to give a bisnorlabdane ketone. Reduction of this ketone with lithium aluminium hydride produced a mixture of diols which, through t-butyldimethysilyl triflate protection, afforded a quantitative route to protecting the C-13 ketone in an effort to prevent unwanted intramolecular cyclization reactions. Dehydration of the tertiary alcohol moiety at C-8 with phosphorous oxychloride yielded the Δ⁸·¹⁵ exocyclic alkene required for the next oxidation step. Ozonolysis succeeded in producing the desired C-8 ketone after much deliberation and research into alternative oxidation strategies. Methyl lithium methylation quantitatively afforded the desired a-methyl substitution at C-8, identified at the onset as the key step in the synthesis. Tetra-butylarnmonium fluoride deprotection yielded the 8ß,13-dihydoxylated product, which was in turn subjected to a Swern oxidition to give the desired 8ß-hydroxy-bisnorlabda-13-one. A modified Horner-Wadsworth-Emmons reaction allowed for elaboration at C-13 to yield a to Δ¹³ olefin with a terminal C-15 ethyl ester. Diisobutylaluminium hydride reduction of the ester produced the desired labd-13-en-8ß, 15-diol (46) in a low overall yield of 3.4%. Although opportunities for optimization of at least three steps in the synthesis exist, time constraints prevented both optimization of these steps and an investigation of the oxidation of 46 to 6. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2002
Teacher responses to the Namibian education reform : a case study of two Caprivi schools
- Authors: Kamwi, Kamwi Kenneth
- Date: 2002
- Subjects: Education -- Namibia Education and state -- Namibia Educational change -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1791 , http://hdl.handle.net/10962/d1003676
- Description: Effective implementation of education reforms consists of alterations in curriculum materials, instructional practices and behaviour, beliefs and understandings on the part of the teachers involved in the reform (Fullan and Hargreaves, 1993: 5). A process of implementation is therefore, a learning process, learning how to do something new (ibid.). This study was done to establish how Biology teachers in Caprivi have responded to the reform process ten years down the line. I used a qualitative case study of two secondary schools. Four Biology teachers, two school principals and two groups of learners participated in the study. Data was collected by means of interviews, lesson observations, a workshop, and school inventories. The data was analysed within an interpretive framework. The results of the study show a move into 'activity-based teaching'. It shows a shift from the traditional transmission teaching approach. In general teachers seem to equate 'activity-based teaching' with the learner-centred approach.
- Full Text:
- Date Issued: 2002
- Authors: Kamwi, Kamwi Kenneth
- Date: 2002
- Subjects: Education -- Namibia Education and state -- Namibia Educational change -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1791 , http://hdl.handle.net/10962/d1003676
- Description: Effective implementation of education reforms consists of alterations in curriculum materials, instructional practices and behaviour, beliefs and understandings on the part of the teachers involved in the reform (Fullan and Hargreaves, 1993: 5). A process of implementation is therefore, a learning process, learning how to do something new (ibid.). This study was done to establish how Biology teachers in Caprivi have responded to the reform process ten years down the line. I used a qualitative case study of two secondary schools. Four Biology teachers, two school principals and two groups of learners participated in the study. Data was collected by means of interviews, lesson observations, a workshop, and school inventories. The data was analysed within an interpretive framework. The results of the study show a move into 'activity-based teaching'. It shows a shift from the traditional transmission teaching approach. In general teachers seem to equate 'activity-based teaching' with the learner-centred approach.
- Full Text:
- Date Issued: 2002
The adaptation of the Clark (1997) treatment for social phobia into a group therapy format, and a preliminary evaluation
- Authors: Kannan, Swetha
- Date: 2002
- Subjects: Social phobia -- Treatment , Group psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3109 , http://hdl.handle.net/10962/d1004547 , Social phobia -- Treatment , Group psychotherapy
- Description: Clark and Wells (1995) constructed a comprehensive cognitive model of social phobic behaviour, in terms of which social phobic behaviour is activated and maintained by a system consisting of negative thoughts and beliefs, anxiety s)mptoms, avoidance and safety behaviours, and processing of self as a social object. The interaction of these elements creates a series of vicious circles which escalate and which keep the phobic individual in a state of chronic -disability, either because they chronically avoid significant social situations or because they find themselves incapacitated by anxiety when they enter them. The Clark and Wells (1995) treatment programme is designed to alleviate the social phobia by targeting the components that form the vicious maintenance cycle and replacing these by new patterns of cognition and behaviour. This treatment programme was designed for individual treatment, and the present study adapted it to a group format. Seven social phobic university students participated in the adapted group treatment format over the course of 13, 2-hour group sessions. Regular assessment of participants' response to the programme was carried out weekly and at two follow-up assessments, with the use of a series of questionnaires. In addition, sessions were audio taped and videotaped, facilitators took notes during sessions and keep records made by participants of their homework exercises. Individual case studies were written for all participants (including two non-completers) in which case narratives were juxtaposed against their responses to each of the self-report questionnaires. These we used as a basis for evaluating the validity of the Clark and Wells theoretical model and in examining the effectiveness of the treatment programme in bringing to awareness and interrupting the cycles that maintained the phobic behaviour. It is concluded that the group programme showed evidence of being very effective and, a group treatment manual was constructed so that it can be employed clinically and in future research.
- Full Text:
- Date Issued: 2002
- Authors: Kannan, Swetha
- Date: 2002
- Subjects: Social phobia -- Treatment , Group psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3109 , http://hdl.handle.net/10962/d1004547 , Social phobia -- Treatment , Group psychotherapy
- Description: Clark and Wells (1995) constructed a comprehensive cognitive model of social phobic behaviour, in terms of which social phobic behaviour is activated and maintained by a system consisting of negative thoughts and beliefs, anxiety s)mptoms, avoidance and safety behaviours, and processing of self as a social object. The interaction of these elements creates a series of vicious circles which escalate and which keep the phobic individual in a state of chronic -disability, either because they chronically avoid significant social situations or because they find themselves incapacitated by anxiety when they enter them. The Clark and Wells (1995) treatment programme is designed to alleviate the social phobia by targeting the components that form the vicious maintenance cycle and replacing these by new patterns of cognition and behaviour. This treatment programme was designed for individual treatment, and the present study adapted it to a group format. Seven social phobic university students participated in the adapted group treatment format over the course of 13, 2-hour group sessions. Regular assessment of participants' response to the programme was carried out weekly and at two follow-up assessments, with the use of a series of questionnaires. In addition, sessions were audio taped and videotaped, facilitators took notes during sessions and keep records made by participants of their homework exercises. Individual case studies were written for all participants (including two non-completers) in which case narratives were juxtaposed against their responses to each of the self-report questionnaires. These we used as a basis for evaluating the validity of the Clark and Wells theoretical model and in examining the effectiveness of the treatment programme in bringing to awareness and interrupting the cycles that maintained the phobic behaviour. It is concluded that the group programme showed evidence of being very effective and, a group treatment manual was constructed so that it can be employed clinically and in future research.
- Full Text:
- Date Issued: 2002
The biology and molecular ecology of floating sulphur biofilms
- Authors: Bowker, Michelle Louise
- Date: 2002
- Subjects: Biofilms , Microbial ecology , Sulfur
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4056 , http://hdl.handle.net/10962/d1004117 , Biofilms , Microbial ecology , Sulfur
- Description: Floating sulphur biofilms have been observed to occur on sulphate-containing natural systems and waste stabilization ponds. It has been postulated that these biofilms form on the surface of the water because sulphate reducing bacteria present in the bottom layers of the water body reduce sulphate to sulphide which then diffuses upwards and is oxidized under the correct redox conditions to sulphur by sulphide oxidizing bacteria. Very little information exists on these complex floating systems and in order to study them further, model systems were designed. The Baffle Reactor was successfully used to cultivate floating sulphur biofilms. Conditions within the reactor could be closely scrutinized in the laboratory and it was found that sulphate levels decreased, sulphide levels increased and that sulphur was produced over a period of 2 weeks. The success of this system led to it being scaled-up and currently a method to harvest sulphur from the biofilm is under development. It is thought that biofilms are highly complex, heterogeneous structures with different bacteria distributed in different layers. Preliminary work suggested that bacteria were differentially distributed along nutrient and oxygen gradients within the biofilm. Biofilms are very thin structures and therefore difficult to study and Gradient systems were developed in an attempt to spatially separate the biofilm species into functional layers. Gradient Tubes were designed; these provided a gradient of high-sulphide, low oxygen conditions to high-oxygen, low-sulphide conditions. Bacteria were observed to grow in different layers of these systems. The Gradient Tubes could be sectioned and the chemical characteristics of each section as well as the species present could be determined. Silicon Tubular Bioreactors were also developed and these were very efficient at producing large amounts of sulphur under strictly controlled redox conditions. Microscopy and molecular methods including the amplification of a section of Ribosomal Ribonucleic acid by Polymerase Chain Reaction were used in an attempt to characterize the populations present in these biofilm systems. Denaturing Gradient Gel Electrophoresis was used to create band profiles of the populations; individual bands were excised from the gels and sequenced. Identified species included Ectothiorhodospira sp., Dethiosulfovibrio russensis, Pseudomonas geniculata, Thiobacillus baregensis and Halothiobacillus kellyi.
- Full Text:
- Date Issued: 2002
- Authors: Bowker, Michelle Louise
- Date: 2002
- Subjects: Biofilms , Microbial ecology , Sulfur
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4056 , http://hdl.handle.net/10962/d1004117 , Biofilms , Microbial ecology , Sulfur
- Description: Floating sulphur biofilms have been observed to occur on sulphate-containing natural systems and waste stabilization ponds. It has been postulated that these biofilms form on the surface of the water because sulphate reducing bacteria present in the bottom layers of the water body reduce sulphate to sulphide which then diffuses upwards and is oxidized under the correct redox conditions to sulphur by sulphide oxidizing bacteria. Very little information exists on these complex floating systems and in order to study them further, model systems were designed. The Baffle Reactor was successfully used to cultivate floating sulphur biofilms. Conditions within the reactor could be closely scrutinized in the laboratory and it was found that sulphate levels decreased, sulphide levels increased and that sulphur was produced over a period of 2 weeks. The success of this system led to it being scaled-up and currently a method to harvest sulphur from the biofilm is under development. It is thought that biofilms are highly complex, heterogeneous structures with different bacteria distributed in different layers. Preliminary work suggested that bacteria were differentially distributed along nutrient and oxygen gradients within the biofilm. Biofilms are very thin structures and therefore difficult to study and Gradient systems were developed in an attempt to spatially separate the biofilm species into functional layers. Gradient Tubes were designed; these provided a gradient of high-sulphide, low oxygen conditions to high-oxygen, low-sulphide conditions. Bacteria were observed to grow in different layers of these systems. The Gradient Tubes could be sectioned and the chemical characteristics of each section as well as the species present could be determined. Silicon Tubular Bioreactors were also developed and these were very efficient at producing large amounts of sulphur under strictly controlled redox conditions. Microscopy and molecular methods including the amplification of a section of Ribosomal Ribonucleic acid by Polymerase Chain Reaction were used in an attempt to characterize the populations present in these biofilm systems. Denaturing Gradient Gel Electrophoresis was used to create band profiles of the populations; individual bands were excised from the gels and sequenced. Identified species included Ectothiorhodospira sp., Dethiosulfovibrio russensis, Pseudomonas geniculata, Thiobacillus baregensis and Halothiobacillus kellyi.
- Full Text:
- Date Issued: 2002
The characterisation of a South African isolate of Cryptophlebia leucotreta Granulovirus (CIGV)
- Authors: Singh, Shalene
- Date: 2002
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4067 , http://hdl.handle.net/10962/d1004929 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Description: The false codling moth (FCM), Cryptophlehia Leucatreta, causes widespread damage to economically important fruit crops throughout sub-Saharan Africa. Fruit are rendered unfit for consumption once they have been stung by FCM larvae. Larval infestation of fruit can lead to significant pre-harvest losses or post-harvest waste, posing a major problem to the citrus industry. Current control of the pest includes the use of chemical pesticides. The larval form of FCM is known to be infected by a granulovirus called Cryptophlebia leucotreta granulovirus (CIGV). Granuloviruses are highly specific against their hosts and are harmless to vertebrates, plants and the environment. The development of CIGV into a biological control agent would offer an attractive and safer alternative for the control of this pest. A full characterisation of CIGV is required prior to the virus being disseminated into the environment. In this project, the characteristics of CIGV will be examined. Viral DNA was extracted from infected larvae and the DNA analysed by restriction fragment length polymorphism (RFLP). Fragmentation profiles of the South African and Cape Verde (CV3) isolates of the virus were compared, revealing distinct differences between them. The size of the CIGV-SA genome was calculated to be 112 kbp, identical to the size of the CV3 isolate. Physical maps for five restriction enzymes were constructed for the CIGV-SA genome. The alignment of these maps with maps the CV3 isolate (for the same enzymes) further highlighted the differences between the isolates. The genetic engineering of granuloviruses could significantly improve the speed of kill of these viruses. Therefore essential genes like egt and granulin were isolated (by PCR) and their position located in the genome. Both genes were sequenced and their phylogeny with other granulin and egt genes investigated. Finally, tbe incidence of CIGV in natural populations of FCM larvae was investigated, by screening field-collected larvae for the presence of the virus. CIGV was successfully detected from dot blots of larval DNA using both radiolabelled and non-radiolabelled probes and by PCR. Trends regarding the incidence of CIGV in natural populations of larvae were also determined.
- Full Text:
- Date Issued: 2002
- Authors: Singh, Shalene
- Date: 2002
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4067 , http://hdl.handle.net/10962/d1004929 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Description: The false codling moth (FCM), Cryptophlehia Leucatreta, causes widespread damage to economically important fruit crops throughout sub-Saharan Africa. Fruit are rendered unfit for consumption once they have been stung by FCM larvae. Larval infestation of fruit can lead to significant pre-harvest losses or post-harvest waste, posing a major problem to the citrus industry. Current control of the pest includes the use of chemical pesticides. The larval form of FCM is known to be infected by a granulovirus called Cryptophlebia leucotreta granulovirus (CIGV). Granuloviruses are highly specific against their hosts and are harmless to vertebrates, plants and the environment. The development of CIGV into a biological control agent would offer an attractive and safer alternative for the control of this pest. A full characterisation of CIGV is required prior to the virus being disseminated into the environment. In this project, the characteristics of CIGV will be examined. Viral DNA was extracted from infected larvae and the DNA analysed by restriction fragment length polymorphism (RFLP). Fragmentation profiles of the South African and Cape Verde (CV3) isolates of the virus were compared, revealing distinct differences between them. The size of the CIGV-SA genome was calculated to be 112 kbp, identical to the size of the CV3 isolate. Physical maps for five restriction enzymes were constructed for the CIGV-SA genome. The alignment of these maps with maps the CV3 isolate (for the same enzymes) further highlighted the differences between the isolates. The genetic engineering of granuloviruses could significantly improve the speed of kill of these viruses. Therefore essential genes like egt and granulin were isolated (by PCR) and their position located in the genome. Both genes were sequenced and their phylogeny with other granulin and egt genes investigated. Finally, tbe incidence of CIGV in natural populations of FCM larvae was investigated, by screening field-collected larvae for the presence of the virus. CIGV was successfully detected from dot blots of larval DNA using both radiolabelled and non-radiolabelled probes and by PCR. Trends regarding the incidence of CIGV in natural populations of larvae were also determined.
- Full Text:
- Date Issued: 2002
The concurrent jurisdiction of the Labour Court and the High Court
- Authors: Wagener, Pieter Cornelius
- Date: 2002
- Subjects: South Africa. High Court , South Africa. Labour Court , Exclusive and concurrent legislative powers -- South Africa , Law, Interpretation and construction
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11051 , http://hdl.handle.net/10948/286 , South Africa. High Court , South Africa. Labour Court , Exclusive and concurrent legislative powers -- South Africa , Law, Interpretation and construction
- Description: An overview is given of the difficulties surrounding the concurrent jurisdiction of the Labour Court and High Court The main categories of the jurisdictional dispute are identified and systemised. The main branches are those of statutory overlap and interpretation of statutes. Statutory overlap concerns matters remaining from the industrial court era, urgent applications, delict and law of contract. Statutory interpretation mainly involves the interpretation of provisions in the Bill of Rights of the Constitution. An overview of the principles of jurisdiction with respect to the different courts, as well as a brief historical review of the development of such jurisdiction is given. Particular attention is given to the role of fundamental rights in the Constitution. Broad principles are identified whereby the difficulties may be addressed.
- Full Text:
- Date Issued: 2002
- Authors: Wagener, Pieter Cornelius
- Date: 2002
- Subjects: South Africa. High Court , South Africa. Labour Court , Exclusive and concurrent legislative powers -- South Africa , Law, Interpretation and construction
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11051 , http://hdl.handle.net/10948/286 , South Africa. High Court , South Africa. Labour Court , Exclusive and concurrent legislative powers -- South Africa , Law, Interpretation and construction
- Description: An overview is given of the difficulties surrounding the concurrent jurisdiction of the Labour Court and High Court The main categories of the jurisdictional dispute are identified and systemised. The main branches are those of statutory overlap and interpretation of statutes. Statutory overlap concerns matters remaining from the industrial court era, urgent applications, delict and law of contract. Statutory interpretation mainly involves the interpretation of provisions in the Bill of Rights of the Constitution. An overview of the principles of jurisdiction with respect to the different courts, as well as a brief historical review of the development of such jurisdiction is given. Particular attention is given to the role of fundamental rights in the Constitution. Broad principles are identified whereby the difficulties may be addressed.
- Full Text:
- Date Issued: 2002
The determination of a strategy for the implementation of learnerships in the catalytic converter canning industry in the Eastern Cape
- Authors: Heather, Keith Buxmann
- Date: 2002
- Subjects: Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10851 , http://hdl.handle.net/10948/117 , Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Description: The Eastern Cape Region, once had sufficient job seekers with automotive component manufacturing skills and experience. Indications are that this pool has been desiccated. The draining of skills out of the area is starting to affect growth potential and competitiveness in the industry in the area. In 1998, the Skills Development Act was passed to implement the National Skills Development Plan, and to encourage employers to train personnel. The strategy promotes a three faceted approach to encourage the development of skills; Workplace Skills Development Plans, Learnerships and Sector Specific Initiatives. This study will focus on the implementation of learnerships in the Catalytic Converter Canning Industry. The aim of this research is to verify the skills shortages; identify which skills are required by the Catalytic Converter Canning Industry in the Eastern Cape and propose a strategy of addressing these needs by means of learnerships. By studying the Legislation supporting the National Skills Development Plan, conducting a literature study, and interviewing knowledgeable people in the industry, the skills requirements of the industry were identified. Thereafter, a questionnaire was drawn up and completed together with representatives from Eberspächer South Africa, Faurecia Exhaust Systems South Africa, Precision Exhaust Systems and Tenneco Automotive South Africa, the active manufacturers of catalytic converters, for OEM’s worldwide, who are based in the Eastern Cape Region. The empirical study confirmed the findings of the research and skills deficiencies were identified. In conclusion, a strategy is proposed whereby the Catalytic Converter Canning Industry could address the skills shortage by the implementation and development of learnerships.
- Full Text:
- Date Issued: 2002
- Authors: Heather, Keith Buxmann
- Date: 2002
- Subjects: Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10851 , http://hdl.handle.net/10948/117 , Automobiles -- Catalytic converters , Automobile industry and trade -- South Africa -- Eastern Cape , Apprenticeship programs -- South Africa -- Eastern Cape
- Description: The Eastern Cape Region, once had sufficient job seekers with automotive component manufacturing skills and experience. Indications are that this pool has been desiccated. The draining of skills out of the area is starting to affect growth potential and competitiveness in the industry in the area. In 1998, the Skills Development Act was passed to implement the National Skills Development Plan, and to encourage employers to train personnel. The strategy promotes a three faceted approach to encourage the development of skills; Workplace Skills Development Plans, Learnerships and Sector Specific Initiatives. This study will focus on the implementation of learnerships in the Catalytic Converter Canning Industry. The aim of this research is to verify the skills shortages; identify which skills are required by the Catalytic Converter Canning Industry in the Eastern Cape and propose a strategy of addressing these needs by means of learnerships. By studying the Legislation supporting the National Skills Development Plan, conducting a literature study, and interviewing knowledgeable people in the industry, the skills requirements of the industry were identified. Thereafter, a questionnaire was drawn up and completed together with representatives from Eberspächer South Africa, Faurecia Exhaust Systems South Africa, Precision Exhaust Systems and Tenneco Automotive South Africa, the active manufacturers of catalytic converters, for OEM’s worldwide, who are based in the Eastern Cape Region. The empirical study confirmed the findings of the research and skills deficiencies were identified. In conclusion, a strategy is proposed whereby the Catalytic Converter Canning Industry could address the skills shortage by the implementation and development of learnerships.
- Full Text:
- Date Issued: 2002
The determination of critical success factors that impact on the performance of SMEs in e-commerce
- Authors: Zeelie, Eben Johannes
- Date: 2002
- Subjects: Electronic commerce , Small business -- Management , New business enterprises -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10905 , http://hdl.handle.net/10948/118 , Electronic commerce , Small business -- Management , New business enterprises -- Management
- Description: The research problem addressed in this study is the determination of the critical success factors for SMEs in e-commerce. To achieve the objective, an integrated list of critical success factors, gathered from practitioner- and academic literature, had to be identified. The integrated list was developed through the following sub-processes: · The first consisted of a literature survey of the sources and the identification of critical success factors, which lead to insights into the role of critical success factors in strategic management and the objectivity of the CSF identification process. The second comprised surveying the literature dealing specifically with the unique characteristics of SMEs, to identify factors that are critical to the survival and growth of SMEs. · The third consisted of a survey of the academic and practitioner literature dealing with critical success factors in e-commerce, in order to develop an integrated list of critical success factors for SMEs in ecommerce. The integrated list that emerged from the literature study consisted of the following seventeen critical success factors: 1. Target the right customers 2. Involve all stakeholders 3. Provide access to all customer information 4. User-friendly web design 5. Let customers help themselves 6. Offer online and offline assistance to customer enquiries 7. Deliver personalized service 8. Foster online community 9. Top management support 10. Technical infrastructure 11. Security and control of the e-commerce system 12. Promotion of site 13. Financial planning and control of project 14. Loyalty 15. Development of a business plan 16. Branding of the site 17. Shipping and fulfilment The integrated list was used as the basis for the compilation of a survey questionnaire to identify the eight most critical success factors for SMEs in ecommerce. The survey questionnaire was sent to SMEs that are members of the Port Elizabeth Chamber of Commerce and Industry, have a website and comply with the criteria for SMEs. The empirical study identified the eight most critical success factors for SMEs in e-commerce and indicated strong concurrence with the unique characteristics of SMEs.
- Full Text:
- Date Issued: 2002
- Authors: Zeelie, Eben Johannes
- Date: 2002
- Subjects: Electronic commerce , Small business -- Management , New business enterprises -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10905 , http://hdl.handle.net/10948/118 , Electronic commerce , Small business -- Management , New business enterprises -- Management
- Description: The research problem addressed in this study is the determination of the critical success factors for SMEs in e-commerce. To achieve the objective, an integrated list of critical success factors, gathered from practitioner- and academic literature, had to be identified. The integrated list was developed through the following sub-processes: · The first consisted of a literature survey of the sources and the identification of critical success factors, which lead to insights into the role of critical success factors in strategic management and the objectivity of the CSF identification process. The second comprised surveying the literature dealing specifically with the unique characteristics of SMEs, to identify factors that are critical to the survival and growth of SMEs. · The third consisted of a survey of the academic and practitioner literature dealing with critical success factors in e-commerce, in order to develop an integrated list of critical success factors for SMEs in ecommerce. The integrated list that emerged from the literature study consisted of the following seventeen critical success factors: 1. Target the right customers 2. Involve all stakeholders 3. Provide access to all customer information 4. User-friendly web design 5. Let customers help themselves 6. Offer online and offline assistance to customer enquiries 7. Deliver personalized service 8. Foster online community 9. Top management support 10. Technical infrastructure 11. Security and control of the e-commerce system 12. Promotion of site 13. Financial planning and control of project 14. Loyalty 15. Development of a business plan 16. Branding of the site 17. Shipping and fulfilment The integrated list was used as the basis for the compilation of a survey questionnaire to identify the eight most critical success factors for SMEs in ecommerce. The survey questionnaire was sent to SMEs that are members of the Port Elizabeth Chamber of Commerce and Industry, have a website and comply with the criteria for SMEs. The empirical study identified the eight most critical success factors for SMEs in e-commerce and indicated strong concurrence with the unique characteristics of SMEs.
- Full Text:
- Date Issued: 2002
The development assumptions of Botswana television : an assessment
- Authors: Mmusi, Bishy
- Date: 2002
- Subjects: Television -- Social aspects -- Botswana , Botswana -- Social conditions , AIDS (Disease) -- Botswana
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3511 , http://hdl.handle.net/10962/d1007668 , Television -- Social aspects -- Botswana , Botswana -- Social conditions , AIDS (Disease) -- Botswana
- Description: This study researched a project to set up a national television service for Botswana to find out whether the service could be used for rural development generally, and in particular to assist the Ministry of Health to implement its health projects in the rural areas and including the fight against the AIDS disease. It reviews conceptions of development and also analyses various communication models that usefully inform the conceptualisation of a TV service that can contribute to development. The study was done by going through reports of feasibility studies on the project and through letters of official correspondence among officials of the Government of Botswana who debated the subject of whether or not the country should have a national TV service. The reports and correspondence were supplemented with interviews of key people involved in the implementation of the project, as well as interviews of officials of the Ministry of Health. The findings of the study are that the Botswana television service project started and ended on a footing that forgot about television, a medium that is dependent on professional and organisational capacity and purpose, and as a result the project did not take-off. A qualitative method was used as the study required in-depth interviews during which new issues kept on emerging and nothing could be pre-determined because the study took place as the project was being implemented. The study was completed in June 2000, at a point where the project should have been completed but it was discovered that the station could not go on air as a television service had not been conceptualised and there was no management structure in place and the Government of Botswana appealed to the British Government for the staff of the British Broadcasting Corporation to come quickly to Botswana to rescue the project and put it on track, supposedly. The study has concluded that the Botswana television service project became stillborn because there was a lack of professional and intellectual capacity to conceptualise the service, and instead there had been too much concentration on the construction of the TV building and acquisition of equipment.
- Full Text:
- Date Issued: 2002
- Authors: Mmusi, Bishy
- Date: 2002
- Subjects: Television -- Social aspects -- Botswana , Botswana -- Social conditions , AIDS (Disease) -- Botswana
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3511 , http://hdl.handle.net/10962/d1007668 , Television -- Social aspects -- Botswana , Botswana -- Social conditions , AIDS (Disease) -- Botswana
- Description: This study researched a project to set up a national television service for Botswana to find out whether the service could be used for rural development generally, and in particular to assist the Ministry of Health to implement its health projects in the rural areas and including the fight against the AIDS disease. It reviews conceptions of development and also analyses various communication models that usefully inform the conceptualisation of a TV service that can contribute to development. The study was done by going through reports of feasibility studies on the project and through letters of official correspondence among officials of the Government of Botswana who debated the subject of whether or not the country should have a national TV service. The reports and correspondence were supplemented with interviews of key people involved in the implementation of the project, as well as interviews of officials of the Ministry of Health. The findings of the study are that the Botswana television service project started and ended on a footing that forgot about television, a medium that is dependent on professional and organisational capacity and purpose, and as a result the project did not take-off. A qualitative method was used as the study required in-depth interviews during which new issues kept on emerging and nothing could be pre-determined because the study took place as the project was being implemented. The study was completed in June 2000, at a point where the project should have been completed but it was discovered that the station could not go on air as a television service had not been conceptualised and there was no management structure in place and the Government of Botswana appealed to the British Government for the staff of the British Broadcasting Corporation to come quickly to Botswana to rescue the project and put it on track, supposedly. The study has concluded that the Botswana television service project became stillborn because there was a lack of professional and intellectual capacity to conceptualise the service, and instead there had been too much concentration on the construction of the TV building and acquisition of equipment.
- Full Text:
- Date Issued: 2002
The development of a competency based model for training operators within the confectionery industry
- Authors: Van Heerden, Alan Joshua
- Date: 2002
- Subjects: Employees, Training Of
- Language: English
- Type: Thesis , Masters , MTech (Business Administration)
- Identifier: vital:10914 , http://hdl.handle.net/10948/83 , Employees, Training Of
- Description: Most South African manufacturing companies provide some sort of training for its shop floor employees to help them improve productivity and reduce wastage. Unfortunately, training presented on-the-job to operators is more often than not implemented in an unstructured and unplanned manner, usually when a crisis occurs and fires need to be put out quickly. The introduction of the National Qualifications Framework (NQF) demands that training practitioners structure their training efforts and ensure that all training leads to national qualifications. This study is aimed at making a contribution towards the NQF and in particular, the development of shop floor employees. Firstly, a model for operator training was developed from a survey of the relevant literature. This phase of the study identified the components of the model and their respective guidelines. Secondly, the model was e.mailed to managers working in confectionery companies requesting their opinion on the guidelines of the model. Lastly, the feedback received from the empirical study was evaluated, conclusions were drawn and recommendations made, based on the information obtained from both the literature study and empirical study. The results from the empirical study indicated strong concurrence with the theoretical model on operator training. In contrast to theory that the use of rewards after training results in improved productivity, the majority of respondents disagreed with the implementation of a reward What are the long term benefits to an organization with a productivity reward system in place? · What kind of reward system would work best in the confectionery industry? · How would management implement an effective performancerelated reward system at shop floor level?
- Full Text:
- Date Issued: 2002
The development of a competency based model for training operators within the confectionery industry
- Authors: Van Heerden, Alan Joshua
- Date: 2002
- Subjects: Employees, Training Of
- Language: English
- Type: Thesis , Masters , MTech (Business Administration)
- Identifier: vital:10914 , http://hdl.handle.net/10948/83 , Employees, Training Of
- Description: Most South African manufacturing companies provide some sort of training for its shop floor employees to help them improve productivity and reduce wastage. Unfortunately, training presented on-the-job to operators is more often than not implemented in an unstructured and unplanned manner, usually when a crisis occurs and fires need to be put out quickly. The introduction of the National Qualifications Framework (NQF) demands that training practitioners structure their training efforts and ensure that all training leads to national qualifications. This study is aimed at making a contribution towards the NQF and in particular, the development of shop floor employees. Firstly, a model for operator training was developed from a survey of the relevant literature. This phase of the study identified the components of the model and their respective guidelines. Secondly, the model was e.mailed to managers working in confectionery companies requesting their opinion on the guidelines of the model. Lastly, the feedback received from the empirical study was evaluated, conclusions were drawn and recommendations made, based on the information obtained from both the literature study and empirical study. The results from the empirical study indicated strong concurrence with the theoretical model on operator training. In contrast to theory that the use of rewards after training results in improved productivity, the majority of respondents disagreed with the implementation of a reward What are the long term benefits to an organization with a productivity reward system in place? · What kind of reward system would work best in the confectionery industry? · How would management implement an effective performancerelated reward system at shop floor level?
- Full Text:
- Date Issued: 2002
The development of a financial plan to partly cover the cost of frail care in a retirement village in George
- Authors: Brink, F J
- Date: 2002
- Subjects: Older people -- Care -- South Africa , Frail elderly -- Medical care -- South Africa -- George , Frail elderly -- Care -- South Africa -- George
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10919 , http://hdl.handle.net/10948/84 , Older people -- Care -- South Africa , Frail elderly -- Medical care -- South Africa -- George , Frail elderly -- Care -- South Africa -- George
- Description: The world population is ageing, and this is also relevant to South Africa. At the same time the potential support ratio (the number of persons aged 15 to 64 years per one older person aged 65 years or older) is falling, and the dependency burden on potential workers increases. To alleviate the financial burden on the aged, and their families, it has become necessary to develop a financial plan to cover the cost of frail care. The overall purpose of this research is to determine whether any financial plans exist which are relevant. If nothing existed, a plan had to be developed. The research methodology for this study comprised the following steps: Firstly, the demographics of the world and South Africa were researched. The concept of frail (long-term) care in the United States of America and New Zealand was investigated to determine what is available. The subsidisation concept of the South African Government towards caring for the elderly was also investigated. Secondly, a questionnaire was sent to the residents of five retirement complexes in George to determine their interest in such a plan. The records of the frail care unit that these residents utilise were analysed to determine the number of residents needing frail care. A comparative study of the cost of frail care in the Southern Cape was undertaken. Thirdly, two options to partly subsidise the cost of frail care were examined, where the first option covers the running cost, and the second option, subsidising one third of the frail care cost, builds up a sustainable fund after the first five year period. The funds of the second option can then be utilised in the subsequent years to increase the subsidisation portion of frail care cost. The final step of this study entailed the formulation of recommendations to implement the frail care nursing levy as soon as possible, with special attention given to the following: a) It must be compulsory for new residents to join the fund. b) A yearly capital amount of R100 000 or more is needed to sustain the fund. c) A contract must be drafted to set out all the rules and regulations to the residents. d) An attitude change amongst some residents is required. Individuals must realise that the success of this plan depends upon themselves and with the necessary support could make a significant contribution towards their own peace of mind if and when frail care is needed.
- Full Text:
- Date Issued: 2002
- Authors: Brink, F J
- Date: 2002
- Subjects: Older people -- Care -- South Africa , Frail elderly -- Medical care -- South Africa -- George , Frail elderly -- Care -- South Africa -- George
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10919 , http://hdl.handle.net/10948/84 , Older people -- Care -- South Africa , Frail elderly -- Medical care -- South Africa -- George , Frail elderly -- Care -- South Africa -- George
- Description: The world population is ageing, and this is also relevant to South Africa. At the same time the potential support ratio (the number of persons aged 15 to 64 years per one older person aged 65 years or older) is falling, and the dependency burden on potential workers increases. To alleviate the financial burden on the aged, and their families, it has become necessary to develop a financial plan to cover the cost of frail care. The overall purpose of this research is to determine whether any financial plans exist which are relevant. If nothing existed, a plan had to be developed. The research methodology for this study comprised the following steps: Firstly, the demographics of the world and South Africa were researched. The concept of frail (long-term) care in the United States of America and New Zealand was investigated to determine what is available. The subsidisation concept of the South African Government towards caring for the elderly was also investigated. Secondly, a questionnaire was sent to the residents of five retirement complexes in George to determine their interest in such a plan. The records of the frail care unit that these residents utilise were analysed to determine the number of residents needing frail care. A comparative study of the cost of frail care in the Southern Cape was undertaken. Thirdly, two options to partly subsidise the cost of frail care were examined, where the first option covers the running cost, and the second option, subsidising one third of the frail care cost, builds up a sustainable fund after the first five year period. The funds of the second option can then be utilised in the subsequent years to increase the subsidisation portion of frail care cost. The final step of this study entailed the formulation of recommendations to implement the frail care nursing levy as soon as possible, with special attention given to the following: a) It must be compulsory for new residents to join the fund. b) A yearly capital amount of R100 000 or more is needed to sustain the fund. c) A contract must be drafted to set out all the rules and regulations to the residents. d) An attitude change amongst some residents is required. Individuals must realise that the success of this plan depends upon themselves and with the necessary support could make a significant contribution towards their own peace of mind if and when frail care is needed.
- Full Text:
- Date Issued: 2002
The development of a marketing plan for an emergency medical service
- Authors: Barley, Kim Wayne
- Date: 2002
- Subjects: Market -- Planning , Emergency medical services , Health facilities -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10853 , http://hdl.handle.net/10948/120 , Market -- Planning , Emergency medical services , Health facilities -- South Africa
- Description: The research problem addressed in this study was to develop a comprehensive marketing plan that would help an emergency medical service (EMS) in the Nelson Mandela Metropolitan Municipality (NMMM), capture a significant market share and gain a competitive advantage over competitors. To achieve this object, a literature study to determine the key components of a marketing plan was undertaken and used as a theoretical model in developing an actual marketing plan. In addition to the literature study, an empirical study was conducted to identify the key issues critical to the development of a marketing plan for the EMS. The survey method used, based on the key components gained from the literature study, consisted of an in-depth scan of the macro-environment and thorough market investigation of the target industry. The investigation involved the general management and senior personnel from the local emergency medical industry, medical aid schemes and private hospitals and clinics delimited in the study. The results of the above literature study were finally combined with the results of the empirical study and a marketing plan for an emergency medical service was developed. This study concludes with recommendations applicable for the implementation of the actual marketing plan.
- Full Text:
- Date Issued: 2002
- Authors: Barley, Kim Wayne
- Date: 2002
- Subjects: Market -- Planning , Emergency medical services , Health facilities -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10853 , http://hdl.handle.net/10948/120 , Market -- Planning , Emergency medical services , Health facilities -- South Africa
- Description: The research problem addressed in this study was to develop a comprehensive marketing plan that would help an emergency medical service (EMS) in the Nelson Mandela Metropolitan Municipality (NMMM), capture a significant market share and gain a competitive advantage over competitors. To achieve this object, a literature study to determine the key components of a marketing plan was undertaken and used as a theoretical model in developing an actual marketing plan. In addition to the literature study, an empirical study was conducted to identify the key issues critical to the development of a marketing plan for the EMS. The survey method used, based on the key components gained from the literature study, consisted of an in-depth scan of the macro-environment and thorough market investigation of the target industry. The investigation involved the general management and senior personnel from the local emergency medical industry, medical aid schemes and private hospitals and clinics delimited in the study. The results of the above literature study were finally combined with the results of the empirical study and a marketing plan for an emergency medical service was developed. This study concludes with recommendations applicable for the implementation of the actual marketing plan.
- Full Text:
- Date Issued: 2002
The development of a model for the assessment of the subject entrepreneurship and business management at the N4 level using an outcomes based education approach
- Authors: Olivier, Marina
- Date: 2002
- Subjects: Curriculum-based assessment -- South Africa , Competency-based education
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10781 , http://hdl.handle.net/10948/86 , Curriculum-based assessment -- South Africa , Competency-based education
- Description: The focus of this study is on assessment in an Outcomes Based Education environment. The question arises as to how assessment of Entrepreneurship and Business Management-N4 can be changed to suit an Outcomes Based Education approach. Action research was used as the research methodology and the findings were reported as case studies. A sample of three colleges in the Eastern Cape was chosen to take part in the study. Only two modules of the Entrepreneurship and Business Management-N4 syllabus were adapted to suit an Outcomes Based Education approach, as the students still had to write the normal external examination at the end of the semester as required by the Department of Education. In the first two cycles the participants implemented Outcomes Based Education in the classroom using only the resources available at the college for the old education system. During the third cycle the researcher implemented Outcomes Based Education in the classroom under the same circumstances, but with the advantage that the researcher benefited from the reflections of the first two cycles. In order for assessment to meet the requirements of an Outcomes Based Education approach, it was necessary to change teaching practices as well. Important aspects such as group work, new assessment methods, the role of resource materials and the training of lecturers were included in the study. At the end of the third cycle a model for the assessment of Entrepreneurship and Business Management-N4 was developed. Recommendations on aspects such as students, lecturers, resources and assessment were made.
- Full Text:
- Date Issued: 2002
- Authors: Olivier, Marina
- Date: 2002
- Subjects: Curriculum-based assessment -- South Africa , Competency-based education
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10781 , http://hdl.handle.net/10948/86 , Curriculum-based assessment -- South Africa , Competency-based education
- Description: The focus of this study is on assessment in an Outcomes Based Education environment. The question arises as to how assessment of Entrepreneurship and Business Management-N4 can be changed to suit an Outcomes Based Education approach. Action research was used as the research methodology and the findings were reported as case studies. A sample of three colleges in the Eastern Cape was chosen to take part in the study. Only two modules of the Entrepreneurship and Business Management-N4 syllabus were adapted to suit an Outcomes Based Education approach, as the students still had to write the normal external examination at the end of the semester as required by the Department of Education. In the first two cycles the participants implemented Outcomes Based Education in the classroom using only the resources available at the college for the old education system. During the third cycle the researcher implemented Outcomes Based Education in the classroom under the same circumstances, but with the advantage that the researcher benefited from the reflections of the first two cycles. In order for assessment to meet the requirements of an Outcomes Based Education approach, it was necessary to change teaching practices as well. Important aspects such as group work, new assessment methods, the role of resource materials and the training of lecturers were included in the study. At the end of the third cycle a model for the assessment of Entrepreneurship and Business Management-N4 was developed. Recommendations on aspects such as students, lecturers, resources and assessment were made.
- Full Text:
- Date Issued: 2002
The development of a model on which to base franchise relationships
- Authors: Kirabira, Godfrey
- Date: 2002
- Subjects: Franchises (Retail trade) -- South Africa , Franchises (Retail trade) -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10920 , http://hdl.handle.net/10948/85 , Franchises (Retail trade) -- South Africa , Franchises (Retail trade) -- Law and legislation -- South Africa
- Description: This paper aims at developing a model on which to base good quality franchise relationships. The franchise sector has the potential to generate wealth for the franchisee and the franchisor, create employment and be a tool of empowerment. It is also associated with relatively less risk than other forms of self-employment. However, there have been a disturbing number of failures in the sector and reported cases of abuses of franchisees by franchisors. Some franchisors have sought liquidation of franchise units in courts of law. An investigation was commissioned into the sector with the objective of uncovering problems in the quality of the relationships in the sector. The obligations of both the franchisees and franchisors were stipulated. Aspects of quality were then considered to lay a foundation upon which improvements in the relationships could be based. This was followed by a survey to find the performance gap between the quality of service that was expected from the franchisor and what the franchisees were actually receiving. Five dimensions of service quality – tangibles, reliability, responsiveness, assurance and empathy were empirically investigated. The findings of this research revealed that the quality of service of franchisors fell short in all dimensions. It is arguable that other aspects of quality are being neglected by the franchisors. It is against this backdrop that a model is proposed to improve the quality of service in the franchise relationships. The model incorporates contemporary ideas on quality. Principles of total quality management, quality function deployment, customer satisfaction and self-assessment are applied to the franchise relationship. The use of the model will contribute towards better relationships in the franchise sector.
- Full Text:
- Date Issued: 2002
- Authors: Kirabira, Godfrey
- Date: 2002
- Subjects: Franchises (Retail trade) -- South Africa , Franchises (Retail trade) -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10920 , http://hdl.handle.net/10948/85 , Franchises (Retail trade) -- South Africa , Franchises (Retail trade) -- Law and legislation -- South Africa
- Description: This paper aims at developing a model on which to base good quality franchise relationships. The franchise sector has the potential to generate wealth for the franchisee and the franchisor, create employment and be a tool of empowerment. It is also associated with relatively less risk than other forms of self-employment. However, there have been a disturbing number of failures in the sector and reported cases of abuses of franchisees by franchisors. Some franchisors have sought liquidation of franchise units in courts of law. An investigation was commissioned into the sector with the objective of uncovering problems in the quality of the relationships in the sector. The obligations of both the franchisees and franchisors were stipulated. Aspects of quality were then considered to lay a foundation upon which improvements in the relationships could be based. This was followed by a survey to find the performance gap between the quality of service that was expected from the franchisor and what the franchisees were actually receiving. Five dimensions of service quality – tangibles, reliability, responsiveness, assurance and empathy were empirically investigated. The findings of this research revealed that the quality of service of franchisors fell short in all dimensions. It is arguable that other aspects of quality are being neglected by the franchisors. It is against this backdrop that a model is proposed to improve the quality of service in the franchise relationships. The model incorporates contemporary ideas on quality. Principles of total quality management, quality function deployment, customer satisfaction and self-assessment are applied to the franchise relationship. The use of the model will contribute towards better relationships in the franchise sector.
- Full Text:
- Date Issued: 2002
The development of an operations strategy for Eissmann South Africa that addresses market requirements and the needs of its customers
- Authors: Richards, Scott
- Date: 2002
- Subjects: Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10899 , http://hdl.handle.net/10948/88 , Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Description: With global competition becoming a key concept in the majority of companies worldwide, it is necessary for organisations to develop operations strategies that enable them to meet their customers‘ needs. Organisations will never be capable of reaching future goals without their customers. For this reason it is imperative for organisations to identify what competitive factors are required by the market, and which performance objectives are needed in order to increase the competitiveness of the organisation. In this research, Chapters 1 and 2 were used to identify the main and subproblems of the research, to delimit the research and to provide literature background to operations strategies and related operations topics. The empirical study in Chapter 3 was used to gather information pertaining to the specific requirements of ESA’s customers, and the operations performanceof ESA. Chapter 4 was used to analyse the data gathered from the empirical study. From this analysis it was possible for the researcher to identify the specific requirements of ESA’s customers and the operations performance of ESA. Chapter 5 was used to provide recommendations to bridge the performance gap between the customer requirements and the operations performance of ESA. By effectively implementing all of the recommendations suggested in this research, ESA will be able to improve its operation performance and meet the specific requirements of its market and its customers.
- Full Text:
- Date Issued: 2002
- Authors: Richards, Scott
- Date: 2002
- Subjects: Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10899 , http://hdl.handle.net/10948/88 , Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Description: With global competition becoming a key concept in the majority of companies worldwide, it is necessary for organisations to develop operations strategies that enable them to meet their customers‘ needs. Organisations will never be capable of reaching future goals without their customers. For this reason it is imperative for organisations to identify what competitive factors are required by the market, and which performance objectives are needed in order to increase the competitiveness of the organisation. In this research, Chapters 1 and 2 were used to identify the main and subproblems of the research, to delimit the research and to provide literature background to operations strategies and related operations topics. The empirical study in Chapter 3 was used to gather information pertaining to the specific requirements of ESA’s customers, and the operations performanceof ESA. Chapter 4 was used to analyse the data gathered from the empirical study. From this analysis it was possible for the researcher to identify the specific requirements of ESA’s customers and the operations performance of ESA. Chapter 5 was used to provide recommendations to bridge the performance gap between the customer requirements and the operations performance of ESA. By effectively implementing all of the recommendations suggested in this research, ESA will be able to improve its operation performance and meet the specific requirements of its market and its customers.
- Full Text:
- Date Issued: 2002
The development of effective promotional strategies to market public FET/Technical Colleges in the Eastern Cape Province
- Authors: Gaika, Nandipha Gloria
- Date: 2002
- Subjects: Universities and colleges -- South Africa -- Business Management , Marketing research -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10940 , http://hdl.handle.net/10948/d1006191 , Universities and colleges -- South Africa -- Business Management , Marketing research -- South Africa
- Description: Education is a powerful and pervasive agent of change. Therefore, it is the key to unlock the doors to development and modernisation. Currently, business and communities knowledge very little about what the FET/Technical College is offering and its importance to the society as whole. Therefore there is a great need to market the technical sector so that the community is knowledgeable about the FET/Technical Colleges. The research conducted focuses on which promotional strategies are effective in marketing the FET Colleges. In order to make technical college students marketable it is necessary to market the institutions effectively so that all the stakeholders can be aware of what technical colleges can offer. Because of high competition in this industry, it is of vital importance not to be out-marketed by competitors by keeping abreast of new trends in promotional strategies. In order to obtain more relevant information about promotional strategies a literature study was conducted to develop a questionnaire to survey the importance of promotional strategies and determine which promotional strategies are being used by the FET Colleges. The East-London, Queenstown and Ezibeleni Public FET Colleges form the respondents. From each college five academic staff, two management members and five students formed the respondents. Community members, business community members, the Department of Education and the Department of Labour representatives were also included in the sample from each of the selected FET Colleges. The findings of the survey revealed the high level of agreement in terms of the importance of the promotional strategies identified in the literature study with the exception of some promotional strategies, which were identified as not compatible with the FET target market. The study recommended that further research be done on a larger sample size focusing on particular stakeholders eg. students of the FET Colleges in a specific area.
- Full Text:
- Date Issued: 2002
- Authors: Gaika, Nandipha Gloria
- Date: 2002
- Subjects: Universities and colleges -- South Africa -- Business Management , Marketing research -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10940 , http://hdl.handle.net/10948/d1006191 , Universities and colleges -- South Africa -- Business Management , Marketing research -- South Africa
- Description: Education is a powerful and pervasive agent of change. Therefore, it is the key to unlock the doors to development and modernisation. Currently, business and communities knowledge very little about what the FET/Technical College is offering and its importance to the society as whole. Therefore there is a great need to market the technical sector so that the community is knowledgeable about the FET/Technical Colleges. The research conducted focuses on which promotional strategies are effective in marketing the FET Colleges. In order to make technical college students marketable it is necessary to market the institutions effectively so that all the stakeholders can be aware of what technical colleges can offer. Because of high competition in this industry, it is of vital importance not to be out-marketed by competitors by keeping abreast of new trends in promotional strategies. In order to obtain more relevant information about promotional strategies a literature study was conducted to develop a questionnaire to survey the importance of promotional strategies and determine which promotional strategies are being used by the FET Colleges. The East-London, Queenstown and Ezibeleni Public FET Colleges form the respondents. From each college five academic staff, two management members and five students formed the respondents. Community members, business community members, the Department of Education and the Department of Labour representatives were also included in the sample from each of the selected FET Colleges. The findings of the survey revealed the high level of agreement in terms of the importance of the promotional strategies identified in the literature study with the exception of some promotional strategies, which were identified as not compatible with the FET target market. The study recommended that further research be done on a larger sample size focusing on particular stakeholders eg. students of the FET Colleges in a specific area.
- Full Text:
- Date Issued: 2002
The effect of a soil-amending hydrogel on Eucalyptus grandis establishment practices in the Zululand forestry region
- Authors: Viero, Paul Walter Mario
- Date: 2002
- Subjects: Eucalyptus grandis
- Language: English
- Type: Thesis , Masters , MTech (Forestry)
- Identifier: vital:10973 , http://hdl.handle.net/10948/90 , Eucalyptus grandis
- Description: To ensure acceptable survival and initial growth of Eucalyptus grandis clonal and clonal hybrid material planted in the cool temperate and sub-tropical climates of Zululand (KwaZulu-Natal, South Africa) the planting seasons are currently restricted to the winter or summer months respectively. The Zululand coast (sub-tropical climate) experiences traditionally hot and humid summers and as a result Eucalyptus planting is largely restricted to the cool and dry winter months when survival is acceptable (90- 95%). In comparison, the Zululand interior (cool temperate climate) experiences moderately cooler summers followed by drier winters. As a result, the Eucalyptus planting season is reversed to that of the Zululand coast, with most of the planting taking place during the summer months with little or no planting occurring during winter. To ensure adequate transplant survival during and beyond these periods, transplants are planted with large volumes of water at a high cost. To determine whether it was possible to significantly reduce current water volumes at planting and therefore reduce costs, and to potentially extend the current planting seasons, two field trials were initiated during traditionally unsuitable planting periods (winter months for the Zululand interior and summer months for the Zululand coast). These trials were established near Kwambonambi on the Zululand coast and at Ntonjaneni in the Zululand interior. Five levels of water were combined with five levels of hydrogel and applied to the pit at planting in a 5 x 5 factorial treatment design for both trials. The tree variates of mortality, height, groundline diameter, crown diameter, corrected leaf surface index (LSIC) and corrected biomass index (BIC) were assessed at regular intervals until the final measurement dates (118 and 128 days after planting for the Ntonjaneni and Kwambonambi trials respectively). For the Kwambonambi trial, the response of transplant survival to the application water was highly significant (p<0,01) 128 days after planting, but not to the application of the hydrogel. Transplant survival nevertheless conformed to the silviculturally accepted norms of 90-95% using the hydrogel, thus water volumes could be significantly reduced without negatively affecting current survival standards. The lack of the expected response of significantly reduced transplant survival to increasing levels of hydrogel could possibly be attributed to the significant rainfall event (146 mm) that fell two days after trial initiation. Increasing levels of both water and hydrogel resulted in significantly enhanced growth (LSIC and BIC: p<0.01) for the final measurement date. For the Ntonjaneni trial, there was a significant (p<0,01) interaction between hydrogel and water, 118 days after planting. There were significant (p<0,01) differences between water only and all hydrogel treatments, with the hydrogel treatments performing significantly better. Optimum transplant survival for water only treatments was 50% using 4000 ml water while that for hydrogel treatments was 100% using 6 g hydrogel with 1000 ml of water and 12 g hydrogel with 2000 ml of water. The variates, corrected leaf surface index and corrected biomass index indicated that tree growth was significantly enhanced by the addition of a hydrogel over all levels of water. A pot trial was subsequently implemented to ascertain whether the significant increases obtained for initial transplant growth for the sandy clay loam soils of Ntonjaneni were due to an initial but unsustainable positive response of the roots to the presence of the hydrogel, or whether root growth was sustainably advantaged by the presence of the hydrogel. There was a highly significant (p<0,01) response of root biomass and above ground biomass over all levels of hydrogel, including a significant positive linear (p<0,01) relationship between increased root biomass and above ground biomass. This clearly indicated that initial root growth was not negatively affected by the addition of the soil-amending hydrogel Stockosorb 400K.
- Full Text:
- Date Issued: 2002
- Authors: Viero, Paul Walter Mario
- Date: 2002
- Subjects: Eucalyptus grandis
- Language: English
- Type: Thesis , Masters , MTech (Forestry)
- Identifier: vital:10973 , http://hdl.handle.net/10948/90 , Eucalyptus grandis
- Description: To ensure acceptable survival and initial growth of Eucalyptus grandis clonal and clonal hybrid material planted in the cool temperate and sub-tropical climates of Zululand (KwaZulu-Natal, South Africa) the planting seasons are currently restricted to the winter or summer months respectively. The Zululand coast (sub-tropical climate) experiences traditionally hot and humid summers and as a result Eucalyptus planting is largely restricted to the cool and dry winter months when survival is acceptable (90- 95%). In comparison, the Zululand interior (cool temperate climate) experiences moderately cooler summers followed by drier winters. As a result, the Eucalyptus planting season is reversed to that of the Zululand coast, with most of the planting taking place during the summer months with little or no planting occurring during winter. To ensure adequate transplant survival during and beyond these periods, transplants are planted with large volumes of water at a high cost. To determine whether it was possible to significantly reduce current water volumes at planting and therefore reduce costs, and to potentially extend the current planting seasons, two field trials were initiated during traditionally unsuitable planting periods (winter months for the Zululand interior and summer months for the Zululand coast). These trials were established near Kwambonambi on the Zululand coast and at Ntonjaneni in the Zululand interior. Five levels of water were combined with five levels of hydrogel and applied to the pit at planting in a 5 x 5 factorial treatment design for both trials. The tree variates of mortality, height, groundline diameter, crown diameter, corrected leaf surface index (LSIC) and corrected biomass index (BIC) were assessed at regular intervals until the final measurement dates (118 and 128 days after planting for the Ntonjaneni and Kwambonambi trials respectively). For the Kwambonambi trial, the response of transplant survival to the application water was highly significant (p<0,01) 128 days after planting, but not to the application of the hydrogel. Transplant survival nevertheless conformed to the silviculturally accepted norms of 90-95% using the hydrogel, thus water volumes could be significantly reduced without negatively affecting current survival standards. The lack of the expected response of significantly reduced transplant survival to increasing levels of hydrogel could possibly be attributed to the significant rainfall event (146 mm) that fell two days after trial initiation. Increasing levels of both water and hydrogel resulted in significantly enhanced growth (LSIC and BIC: p<0.01) for the final measurement date. For the Ntonjaneni trial, there was a significant (p<0,01) interaction between hydrogel and water, 118 days after planting. There were significant (p<0,01) differences between water only and all hydrogel treatments, with the hydrogel treatments performing significantly better. Optimum transplant survival for water only treatments was 50% using 4000 ml water while that for hydrogel treatments was 100% using 6 g hydrogel with 1000 ml of water and 12 g hydrogel with 2000 ml of water. The variates, corrected leaf surface index and corrected biomass index indicated that tree growth was significantly enhanced by the addition of a hydrogel over all levels of water. A pot trial was subsequently implemented to ascertain whether the significant increases obtained for initial transplant growth for the sandy clay loam soils of Ntonjaneni were due to an initial but unsustainable positive response of the roots to the presence of the hydrogel, or whether root growth was sustainably advantaged by the presence of the hydrogel. There was a highly significant (p<0,01) response of root biomass and above ground biomass over all levels of hydrogel, including a significant positive linear (p<0,01) relationship between increased root biomass and above ground biomass. This clearly indicated that initial root growth was not negatively affected by the addition of the soil-amending hydrogel Stockosorb 400K.
- Full Text:
- Date Issued: 2002
The effect of energy and protein nutritional levels on production of breeding ostriches
- Authors: Brand, Zanell
- Date: 2002
- Subjects: Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5805 , http://hdl.handle.net/10962/d1006312 , Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Description: Adequate and appropriate nutrition is essential for the production of high quality commercially farmed animal species. Although South Africa has had a well-established ostrich industry for over a century, little information on ostrich nutrition, in particular the specific nutritional requirements at different stages of production, is available. The industry has consequently relied heavily on data derived from poultry and pigs, but this has often proved to be unsatisfactory for ostriches and has resulted in serious nutritional-related problems. Recent studies on the metabolisable energy of specific components of diet formulations and balanced diets have indicated that ostriches have enhanced digestibility compared with poultry and pigs. At the same time, in the present economic climate, it is necessary to find cost-effective diets for breeding birds without compromising egg and chick production. This study primarily assessed the effect of different dietary protein and energy levels on production parameters and body condition of breeding female and male ostriches. The energy content of the diet appears to be the main constraint to egg production and breeders on low energy diets laid fewer eggs and lost more body condition compared with breeders fed higher energy diets. A diet with 8.5 MJ/kg DM and 10% protein with well balanced amino acids appears to be sufficient for female breeders without compromising production and a diet with 7.5 MJ/kg DM and 10% protein appears suitable for breeding male ostriches. Different dietary energy and protein levels similarly had little or no effect on egg quality and composition. This study also assessed the carry-over effect of the nutritional regime in one year on the production in the following breeding season. Females fed diets as low as 7.5 MJ/kg ME in the previous breeding season produced significantly fewer eggs in the next breeding season, which resulted in lower chick production. Energy had no effect on the percentage infertile eggs or on the initial egg weight. Different levels of dietary protein had no effect on egg production, egg weight, fertility, hatchability and initial chick weight.
- Full Text:
- Date Issued: 2002
- Authors: Brand, Zanell
- Date: 2002
- Subjects: Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5805 , http://hdl.handle.net/10962/d1006312 , Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Description: Adequate and appropriate nutrition is essential for the production of high quality commercially farmed animal species. Although South Africa has had a well-established ostrich industry for over a century, little information on ostrich nutrition, in particular the specific nutritional requirements at different stages of production, is available. The industry has consequently relied heavily on data derived from poultry and pigs, but this has often proved to be unsatisfactory for ostriches and has resulted in serious nutritional-related problems. Recent studies on the metabolisable energy of specific components of diet formulations and balanced diets have indicated that ostriches have enhanced digestibility compared with poultry and pigs. At the same time, in the present economic climate, it is necessary to find cost-effective diets for breeding birds without compromising egg and chick production. This study primarily assessed the effect of different dietary protein and energy levels on production parameters and body condition of breeding female and male ostriches. The energy content of the diet appears to be the main constraint to egg production and breeders on low energy diets laid fewer eggs and lost more body condition compared with breeders fed higher energy diets. A diet with 8.5 MJ/kg DM and 10% protein with well balanced amino acids appears to be sufficient for female breeders without compromising production and a diet with 7.5 MJ/kg DM and 10% protein appears suitable for breeding male ostriches. Different dietary energy and protein levels similarly had little or no effect on egg quality and composition. This study also assessed the carry-over effect of the nutritional regime in one year on the production in the following breeding season. Females fed diets as low as 7.5 MJ/kg ME in the previous breeding season produced significantly fewer eggs in the next breeding season, which resulted in lower chick production. Energy had no effect on the percentage infertile eggs or on the initial egg weight. Different levels of dietary protein had no effect on egg production, egg weight, fertility, hatchability and initial chick weight.
- Full Text:
- Date Issued: 2002
The effect of nutrient levels and ratios on the growth of Microcystis aeruginosa and microcystin production
- Authors: Sember, Craig Stewart
- Date: 2002
- Subjects: Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11076 , http://hdl.handle.net/10948/287 , Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Description: This study reports the findings on the effect of nitrates and phosphates on the biomass and toxin production of various strains of the unicellular non-nitrogen fixing cyanobacterium, Microcystis aeruginosa. The occurrence of blooms of Microcystis aeruginosa and microcystin in freshwater impoundments across the globe has been on the increase lately due to increased levels of eutrophication, resulting in human and animal deaths and illness, as well as drinking and recreational water foulment. A range of environmental factors have been shown to effect growth and microcystin production. Existing literature however is somewhat contradictory as to the effects of these physical and chemical factors on toxin production. Therefore Microcystis aeruginosa strains were cultured under batch and continuous conditions to determine the effect of nitrate and phosphate concentrations and ratios on biomass and toxin production. Cultures were analysed with regards to internal nutrient stores, biomass production, nutrient depletion, photosynthetic efficiency and microcystin production. Results showed that microcystin production correlated to growth rate, photosynthetic efficiency and internal nitrogen stores and that an optimal N:P ratio was associated with microcystin levels, growth rate and photosynthetic efficiency. Results therefore led to the conclusion that the nitrogen, carbon, and phosphate balance within the cell is closely associated with microcystin production. Whether or not microcystin is produced to maintain this balance or produced as a function of this balance remains to be determined.
- Full Text:
- Date Issued: 2002
- Authors: Sember, Craig Stewart
- Date: 2002
- Subjects: Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11076 , http://hdl.handle.net/10948/287 , Microcystis aeruginosa -- Toxicology , Nitrates , Microcystins
- Description: This study reports the findings on the effect of nitrates and phosphates on the biomass and toxin production of various strains of the unicellular non-nitrogen fixing cyanobacterium, Microcystis aeruginosa. The occurrence of blooms of Microcystis aeruginosa and microcystin in freshwater impoundments across the globe has been on the increase lately due to increased levels of eutrophication, resulting in human and animal deaths and illness, as well as drinking and recreational water foulment. A range of environmental factors have been shown to effect growth and microcystin production. Existing literature however is somewhat contradictory as to the effects of these physical and chemical factors on toxin production. Therefore Microcystis aeruginosa strains were cultured under batch and continuous conditions to determine the effect of nitrate and phosphate concentrations and ratios on biomass and toxin production. Cultures were analysed with regards to internal nutrient stores, biomass production, nutrient depletion, photosynthetic efficiency and microcystin production. Results showed that microcystin production correlated to growth rate, photosynthetic efficiency and internal nitrogen stores and that an optimal N:P ratio was associated with microcystin levels, growth rate and photosynthetic efficiency. Results therefore led to the conclusion that the nitrogen, carbon, and phosphate balance within the cell is closely associated with microcystin production. Whether or not microcystin is produced to maintain this balance or produced as a function of this balance remains to be determined.
- Full Text:
- Date Issued: 2002
The effect of selenium in the detoxification of the microcystin hepatotoxins
- Authors: Downs, Kerry
- Date: 2002
- Subjects: Cynaobacterial toxins , Microcystins , Selenium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11070 , http://hdl.handle.net/10948/284 , Cynaobacterial toxins , Microcystins , Selenium
- Description: Blooms of cyanobacteria have been known to cause illness in humans and death in wild and domestic animals. One of the toxins produced by cyanobacteria is microcystin, which is a potent hepatotoxin. Microcystin is taken up by bile acid transporters in the intestine and transported into the liver. After exposure to acute doses of microcystin, severe haemorrhage has been observed along with apoptotic and necrotic hepatocytes. The cytoskeletal structure of the hepatocytes is disrupted and oxidative stress is induced. Selenium, a known anti-oxidant, has been shown to induce increased activity of glutathione peroxidase. Glutathione peroxidase removes peroxides from cells protecting them from oxidative stress. This study set out to determine if selenium could play a role in preventing the damage to mice livers due to microcystin toxin. The protective role of selenium was explored in three main studies: in the first study, the ability of selenium to increase the survival time of mice exposed to a lethal dose of toxin was determined. In the second study the mice were exposed to sublethal chronic doses of toxin over 30 days. The ability of selenium to minimise liver damage under these conditions was determined. The final study investigated the mechanism of the protective effect of selenium. The results of the first study suggested that selenium could extend survival time. In the second study the selenium supplemented mice showed a reduction in the extent of the increase in liver weight and a decrease in the amount of lipid peroxidation induced compared to the mice that received only toxin. The histology of the selenium supplemented mice also showed a decrease in the severity and amount of morphological changes in the liver. The third study indicated that the protection shown by selenium might be mediated by an increase in the glutathione peroxidase (GPX) activity in selenium supplemented mice. This increase in GPX activity would increase the removal of the lipid hydroperoxides and prevent the damage they would cause in the cell. A further result indicated an increase in glutathione S-transferase in only the toxin control mice when compared to the selenium supplemented and control mice. ii In conclusion selenium offers protection against microcystin but further studies need to be done to provide statistically valid results to clarify the level of protection.
- Full Text:
- Date Issued: 2002
- Authors: Downs, Kerry
- Date: 2002
- Subjects: Cynaobacterial toxins , Microcystins , Selenium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11070 , http://hdl.handle.net/10948/284 , Cynaobacterial toxins , Microcystins , Selenium
- Description: Blooms of cyanobacteria have been known to cause illness in humans and death in wild and domestic animals. One of the toxins produced by cyanobacteria is microcystin, which is a potent hepatotoxin. Microcystin is taken up by bile acid transporters in the intestine and transported into the liver. After exposure to acute doses of microcystin, severe haemorrhage has been observed along with apoptotic and necrotic hepatocytes. The cytoskeletal structure of the hepatocytes is disrupted and oxidative stress is induced. Selenium, a known anti-oxidant, has been shown to induce increased activity of glutathione peroxidase. Glutathione peroxidase removes peroxides from cells protecting them from oxidative stress. This study set out to determine if selenium could play a role in preventing the damage to mice livers due to microcystin toxin. The protective role of selenium was explored in three main studies: in the first study, the ability of selenium to increase the survival time of mice exposed to a lethal dose of toxin was determined. In the second study the mice were exposed to sublethal chronic doses of toxin over 30 days. The ability of selenium to minimise liver damage under these conditions was determined. The final study investigated the mechanism of the protective effect of selenium. The results of the first study suggested that selenium could extend survival time. In the second study the selenium supplemented mice showed a reduction in the extent of the increase in liver weight and a decrease in the amount of lipid peroxidation induced compared to the mice that received only toxin. The histology of the selenium supplemented mice also showed a decrease in the severity and amount of morphological changes in the liver. The third study indicated that the protection shown by selenium might be mediated by an increase in the glutathione peroxidase (GPX) activity in selenium supplemented mice. This increase in GPX activity would increase the removal of the lipid hydroperoxides and prevent the damage they would cause in the cell. A further result indicated an increase in glutathione S-transferase in only the toxin control mice when compared to the selenium supplemented and control mice. ii In conclusion selenium offers protection against microcystin but further studies need to be done to provide statistically valid results to clarify the level of protection.
- Full Text:
- Date Issued: 2002