The role of the trade union in post democratic South Africa
- Authors: Collins, Selwyn Charles
- Date: 2004
- Subjects: Labor unions -- South Africa , Labor policy -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11036 , http://hdl.handle.net/10948/354 , Labor unions -- South Africa , Labor policy -- South Africa
- Description: In South Africa, labour has played a central role in shaping the transition to democracy. It remained an open question as to whether labour could sustain it’s involvement during the period of consolidation after the first democratic elections. As was evident in other emerging democracies, economic liberalization often led to stagnation and high costs being imposed on workers, while weakening the state. South African trade unions thus faced formidable problems as they had to respond to rapid economic and industrial change. While being stubborn, South African trade unions remain adaptable enough to survive and grow into the 21st Century. In this dissertation, the writer examines the relevance of trade unions in contemporary South Africa and how they are coming to terms with the deregulated labour market, and the question of globalisation. We look at the emergence of new forms of collective bargaining, the growth of trade unions as partners in a changing workplace and the different ways trade unions are modernising themselves to attract new members. Labour when used as a collective force is capable of shaping democratization through the strategic use of power. Labour has the potential , through participation in negotiated compromises, to ensure that the costs of adjustments are not borne by workers alone. To this end, the South African trade union movement has developed innovative strategies and institutions.
- Full Text:
- Date Issued: 2004
- Authors: Collins, Selwyn Charles
- Date: 2004
- Subjects: Labor unions -- South Africa , Labor policy -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11036 , http://hdl.handle.net/10948/354 , Labor unions -- South Africa , Labor policy -- South Africa
- Description: In South Africa, labour has played a central role in shaping the transition to democracy. It remained an open question as to whether labour could sustain it’s involvement during the period of consolidation after the first democratic elections. As was evident in other emerging democracies, economic liberalization often led to stagnation and high costs being imposed on workers, while weakening the state. South African trade unions thus faced formidable problems as they had to respond to rapid economic and industrial change. While being stubborn, South African trade unions remain adaptable enough to survive and grow into the 21st Century. In this dissertation, the writer examines the relevance of trade unions in contemporary South Africa and how they are coming to terms with the deregulated labour market, and the question of globalisation. We look at the emergence of new forms of collective bargaining, the growth of trade unions as partners in a changing workplace and the different ways trade unions are modernising themselves to attract new members. Labour when used as a collective force is capable of shaping democratization through the strategic use of power. Labour has the potential , through participation in negotiated compromises, to ensure that the costs of adjustments are not borne by workers alone. To this end, the South African trade union movement has developed innovative strategies and institutions.
- Full Text:
- Date Issued: 2004
The Southern Ocean Group at Rhodes University: seventeen years of biological oceanography in the Southern Ocean reviewed
- McQuaid, Christopher D, Froneman, P William
- Authors: McQuaid, Christopher D , Froneman, P William
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6834 , http://hdl.handle.net/10962/d1010423
- Description: This paper reviews the main findings of the Southern Ocean Group at Rhodes University over the last 17 years. A primary contribution has been the development of conceptual models of the physical-biological driving mechanisms that support enormous seasonal populations of land-based top predators at the Prince Edward Islands. Collectively, these models are referred to as the life-support system of the islands. Near-shore subcomponents of the ecosystem, including inshore feeding predators, are largely supported by autochthonous primary production of kelps and localized diatom blooms. These energy sources feed indirectly into top predator populations via the benthic communities. A crucial link is formed by the bottom-dwelling shrimp, Nauticaris marionis, which feeds largely on benthic species and detritus and is eaten by a number of diving seabirds. The frontal systems that lie north and south of the islands are important feeding grounds for offshore feeding birds. A decadal-scale southward shift in the position of the Sub-antarctic Front towards the islands is reflected in increases in populations of these species. , Rhodes Centenary issue
- Full Text:
- Date Issued: 2004
- Authors: McQuaid, Christopher D , Froneman, P William
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6834 , http://hdl.handle.net/10962/d1010423
- Description: This paper reviews the main findings of the Southern Ocean Group at Rhodes University over the last 17 years. A primary contribution has been the development of conceptual models of the physical-biological driving mechanisms that support enormous seasonal populations of land-based top predators at the Prince Edward Islands. Collectively, these models are referred to as the life-support system of the islands. Near-shore subcomponents of the ecosystem, including inshore feeding predators, are largely supported by autochthonous primary production of kelps and localized diatom blooms. These energy sources feed indirectly into top predator populations via the benthic communities. A crucial link is formed by the bottom-dwelling shrimp, Nauticaris marionis, which feeds largely on benthic species and detritus and is eaten by a number of diving seabirds. The frontal systems that lie north and south of the islands are important feeding grounds for offshore feeding birds. A decadal-scale southward shift in the position of the Sub-antarctic Front towards the islands is reflected in increases in populations of these species. , Rhodes Centenary issue
- Full Text:
- Date Issued: 2004
The streets and the gods of truth: memory
- Authors: Duiker, Sello
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454916 , vital:75386 , https://hdl.handle.net/10520/EJC146213
- Description: It is hard to believe that 10 years of democracy have passed since the new democratically elected government came into power in 1994. While growing up in the turbulent '80s, it seemed as if the reign of terror and oppression would never end. But like most things it did.
- Full Text:
- Date Issued: 2004
- Authors: Duiker, Sello
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454916 , vital:75386 , https://hdl.handle.net/10520/EJC146213
- Description: It is hard to believe that 10 years of democracy have passed since the new democratically elected government came into power in 1994. While growing up in the turbulent '80s, it seemed as if the reign of terror and oppression would never end. But like most things it did.
- Full Text:
- Date Issued: 2004
The toxic effect of heavy metals on algal biomass (Spirulina sp.) and carbonic anhydrase activity, an enzyme which is central to algal application in metal precipitation
- Authors: Nightingale, Leigh
- Date: 2004
- Subjects: Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4093 , http://hdl.handle.net/10962/d1007858 , Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Description: Acid rmne drainage (AMD) is a major pollution problem througbout the world, adversely affecting both surface and groundwaters. AMD is principally associated with the mining of sulphide ores. The most commonly associated minerals being sulphur, copper, zinc, silver, gold, lead and uranium. As conventional methods for removing heavy metals from wastewater are often prohibitively expensive, the implementation of biological processes for the removal of heavy metals has become a realistic practice. The objectives of this project was firstly to establish the effect of copper, lead and nickel, heavy metals commonly found in AMD waters, on the enzyme carbonic anhydrase, which is an integral part of the carbon concentrating mechanism (CCM) and secondly, to determine the feasibility of using the alkalinity generated by Spindina for the precipitation of heavy metals from solution. Initially, batch flask experiments were performed and it was found that the algae were able to utilise the bicarbonate supplied in the medium, under CO, limiting conditions, through the induction of their CCM, resulting in the generation of carbonate. The effect of the inhibitors, acetazolamide (AZ) and ethoxyzolamide (EZ), were also investigated in order to determine the importance of carbonic anhydrase (CA) in inorganic carbon accumulation and photosynthesis. Results obtained were consistent with those observed in literature and it was found that at IOOf.LM AZ and EZ, complete inhibition of photosynthesis and carbonic anhydrase occurred, with no oxygen being evolved. The results obtained from the inhibitor experiments substantiate the findings that carbonic anhydrase is an important part of the CCM, and that the dehydration of bicarbonate to carbon dioxide and hydroxide ions, is in fact an enzymatic process regulated by the enzyme carbonic anhydrase and is essential for efficient photosynthesis. The effect of heavy metals on Spirulina was also investigated. Lead, copper and nickel were all found to cause a reduction in the synthesis of chlorophyll a, which resulted in a decrease in photosynthetic efficiency and eventually death of the culture. The morphology of the algae was also severely affected by heavy metals, with degradation and aJmost complete disintegration of the algal filaments occurring. Using the Wilbur-Anderson assay method, carbonic anhydrase activity was found to be lower in the experimental flasks containing heavy metals, than the control flasks, reducing the algae's ability to utilise the bicarbonate in solution for effective photosynthesis. The Wilbur-Anderson assay method did not prove to be a reliable method for measuring changes in enzyme activity as results were found to be erratic. Therefore attempts were made to use an oxygen electrode as an alternative method for determining the effects of various parameters on enzyme activity and photosynthesis, this proved to be more successful. Because of the toxic effects of heavy metals on Spirulina it was decided that the use of the biogenic alkalinity generated by the algae for the precipitation of heavy metals may be successfully employed as an alternative method for bioremediation and metal recovery. Carbonate reacts readily with metals, therefore the carbonate produced by this algal system was used for the precipitation of metals. It was possible to categorise the precipitation reactions observed into three groups, namely those metals which, a) precipitate as hydroxides, b) precipitate as carbonates generated from the dissociation of bicarbonate and c) metals which can only precipitate if there is free carbonate present in solution.
- Full Text:
- Date Issued: 2004
- Authors: Nightingale, Leigh
- Date: 2004
- Subjects: Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4093 , http://hdl.handle.net/10962/d1007858 , Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Description: Acid rmne drainage (AMD) is a major pollution problem througbout the world, adversely affecting both surface and groundwaters. AMD is principally associated with the mining of sulphide ores. The most commonly associated minerals being sulphur, copper, zinc, silver, gold, lead and uranium. As conventional methods for removing heavy metals from wastewater are often prohibitively expensive, the implementation of biological processes for the removal of heavy metals has become a realistic practice. The objectives of this project was firstly to establish the effect of copper, lead and nickel, heavy metals commonly found in AMD waters, on the enzyme carbonic anhydrase, which is an integral part of the carbon concentrating mechanism (CCM) and secondly, to determine the feasibility of using the alkalinity generated by Spindina for the precipitation of heavy metals from solution. Initially, batch flask experiments were performed and it was found that the algae were able to utilise the bicarbonate supplied in the medium, under CO, limiting conditions, through the induction of their CCM, resulting in the generation of carbonate. The effect of the inhibitors, acetazolamide (AZ) and ethoxyzolamide (EZ), were also investigated in order to determine the importance of carbonic anhydrase (CA) in inorganic carbon accumulation and photosynthesis. Results obtained were consistent with those observed in literature and it was found that at IOOf.LM AZ and EZ, complete inhibition of photosynthesis and carbonic anhydrase occurred, with no oxygen being evolved. The results obtained from the inhibitor experiments substantiate the findings that carbonic anhydrase is an important part of the CCM, and that the dehydration of bicarbonate to carbon dioxide and hydroxide ions, is in fact an enzymatic process regulated by the enzyme carbonic anhydrase and is essential for efficient photosynthesis. The effect of heavy metals on Spirulina was also investigated. Lead, copper and nickel were all found to cause a reduction in the synthesis of chlorophyll a, which resulted in a decrease in photosynthetic efficiency and eventually death of the culture. The morphology of the algae was also severely affected by heavy metals, with degradation and aJmost complete disintegration of the algal filaments occurring. Using the Wilbur-Anderson assay method, carbonic anhydrase activity was found to be lower in the experimental flasks containing heavy metals, than the control flasks, reducing the algae's ability to utilise the bicarbonate in solution for effective photosynthesis. The Wilbur-Anderson assay method did not prove to be a reliable method for measuring changes in enzyme activity as results were found to be erratic. Therefore attempts were made to use an oxygen electrode as an alternative method for determining the effects of various parameters on enzyme activity and photosynthesis, this proved to be more successful. Because of the toxic effects of heavy metals on Spirulina it was decided that the use of the biogenic alkalinity generated by the algae for the precipitation of heavy metals may be successfully employed as an alternative method for bioremediation and metal recovery. Carbonate reacts readily with metals, therefore the carbonate produced by this algal system was used for the precipitation of metals. It was possible to categorise the precipitation reactions observed into three groups, namely those metals which, a) precipitate as hydroxides, b) precipitate as carbonates generated from the dissociation of bicarbonate and c) metals which can only precipitate if there is free carbonate present in solution.
- Full Text:
- Date Issued: 2004
The unfair labour practice relating to promotion
- Authors: Abrahams, Dawood
- Date: 2004
- Subjects: Unfair labor practices -- South Africa , Promotions -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11035 , http://hdl.handle.net/10948/329 , Unfair labor practices -- South Africa , Promotions -- South Africa , Labor laws and legislation -- South Africa
- Description: This article deals with the South African law relating to promotions. As promotion disputes mostly arise as alleged unfair labour practices, a short discussion on how the concept of an unfair labour practice developed in South Africa is undertaken. In this regard the common law is studied in order to see whether it makes provision for protection of employees subjected to unfair labour practices relating to promotions. Through this study one soon realises that the common law is in fact inadequate to deal with unfair labour practices relating to promotions, and thus an enquiry into various legislative provisions are undertaken. The impact of the all-important Wiehahn Commission of Enquiry, established in 1979, is also briefly discussed. In this article an attempt is made to define the term ‘promotion’. In this regard reference is made to some cases adjudicated upon by the Commission for Conciliation Mediation and Arbitration (the “CCMA”). The cases referred to seem to favour the view that when one is defining the term ‘promotion’, regard must be had to the employment relationship between the employer and the employee, as well as the nature of the employee’s current work in relation to the work applied for, in order to establish whether in fact a promotion has taken place. It is necessary to consider what unfair conduct is defined as in the context of promotions. It seems that managerial prerogative is at the center of the enquiry into unfair conduct of the employer. Further to the analysis of unfair conduct, various principles that govern both procedural and substantive unfairness are considered. These principles are dealt with separately with reference to case law. Lastly the dispute resolution mechanisms are considered and a brief discussion on remedies is undertaken. The remedies are discussed with reference to case law, as well as the provisions of the Labour Relations Act 66 of 1995 as amended by the Labour Relations Amendment Act 12 of 2002. The broad headings of this article are accordingly unfair labour practices, definition of promotions, unfair conduct of the employer, onus of proof and remedies. It is concluded with the proposition that once an employer has set policies and procedures in place in dealing with promotions, then such an employer should stick to those policies and procedures within the context of the law, as well as within the percepts of the vague and nebulous term of ‘fairness’. Should the employer fail to do so, the majority of cases indicate that such an employer will be guilty of an unfair labour practice relating to promotion.
- Full Text:
- Date Issued: 2004
- Authors: Abrahams, Dawood
- Date: 2004
- Subjects: Unfair labor practices -- South Africa , Promotions -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11035 , http://hdl.handle.net/10948/329 , Unfair labor practices -- South Africa , Promotions -- South Africa , Labor laws and legislation -- South Africa
- Description: This article deals with the South African law relating to promotions. As promotion disputes mostly arise as alleged unfair labour practices, a short discussion on how the concept of an unfair labour practice developed in South Africa is undertaken. In this regard the common law is studied in order to see whether it makes provision for protection of employees subjected to unfair labour practices relating to promotions. Through this study one soon realises that the common law is in fact inadequate to deal with unfair labour practices relating to promotions, and thus an enquiry into various legislative provisions are undertaken. The impact of the all-important Wiehahn Commission of Enquiry, established in 1979, is also briefly discussed. In this article an attempt is made to define the term ‘promotion’. In this regard reference is made to some cases adjudicated upon by the Commission for Conciliation Mediation and Arbitration (the “CCMA”). The cases referred to seem to favour the view that when one is defining the term ‘promotion’, regard must be had to the employment relationship between the employer and the employee, as well as the nature of the employee’s current work in relation to the work applied for, in order to establish whether in fact a promotion has taken place. It is necessary to consider what unfair conduct is defined as in the context of promotions. It seems that managerial prerogative is at the center of the enquiry into unfair conduct of the employer. Further to the analysis of unfair conduct, various principles that govern both procedural and substantive unfairness are considered. These principles are dealt with separately with reference to case law. Lastly the dispute resolution mechanisms are considered and a brief discussion on remedies is undertaken. The remedies are discussed with reference to case law, as well as the provisions of the Labour Relations Act 66 of 1995 as amended by the Labour Relations Amendment Act 12 of 2002. The broad headings of this article are accordingly unfair labour practices, definition of promotions, unfair conduct of the employer, onus of proof and remedies. It is concluded with the proposition that once an employer has set policies and procedures in place in dealing with promotions, then such an employer should stick to those policies and procedures within the context of the law, as well as within the percepts of the vague and nebulous term of ‘fairness’. Should the employer fail to do so, the majority of cases indicate that such an employer will be guilty of an unfair labour practice relating to promotion.
- Full Text:
- Date Issued: 2004
The use and performance of recycling polypropylene in lead-acid battery cases
- Authors: Rust, Nico
- Date: 2004
- Subjects: Polypropylene , Lead-acid batteries
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10978 , http://hdl.handle.net/10948/269 , Polypropylene , Lead-acid batteries
- Description: Polypropylene has proven to be the ideal material for the outer shell of the lead acid batteries. Due to its mold-ability and inert properties the material provides a capsule for the functioning components of the lead acid battery and can withstand a variety conditions encountered during its application, such as impact shock resistance, high and low temperatures and acid resistance. Polypropylene has however become of great concern with regards to environmental pollution since it is generally resistant to normal conditions of degradation and can only be properly disposed of by incineration. This factor has encouraged the industry to find ways to regenerate spent polypropylene. A good example of such a process is the recycling of lead acid batteries. This allows not only for the regeneration of lead, but also for the recycling of polypropylene in the manufacturing of battery cases. There are some cost advantages in using recycled polypropylene. However it does have its disadvantages in that the material does start to deteriorate after multiple processes. A common practice amongst battery manufacturers is to add virgin polypropylene to the recycled material in order to ensure performance consistency. The comparative study investigated the use of various ratios of virgin and recycled PP in the manufacturing of lead acid battery cases and their influence on the physical properties and performance of the final material. The degradation of PP was also investigated as the material was subjected to multiple manufacturing processes where the influence of stabilizers was further considered. A common technique of PP analysis such as MFI was shown to be an effective technique to maintain good quality control. The study further showed that it is important that the material grade of PP used in the manufacturing of the battery case and lid is compatible in order to allow for effective heating sealing of the two components. Polypropylene has a waxy surface finish and it is generally difficult to label or write on. Labels tend to fall off in application and make it difficult to maintain a track record of the manufactured batteries with time. This study showed successfully that a laser activated dye can be added to the PP without influencing its color or its performance. This allows for successful labeling of battery cases by various bar coding writers that can trace the battery through its manufacturing process. Lead acid batteries are often operated outside the specified temperature range that is determined by battery manufacturers resulting in premature failure. These failures can occur within the warranty period of the battery and result in illicit claims since the monitoring of the batteries in its application was not possible. A suitable temperature monitoring device was designed that would be incorporated into the vent cap or lid of the battery case. The device contained temperature sensitive indicators that would undergo a permanent color change at specified temperatures thereby giving the battery manufacturer an indication as to the maximum temperature the battery was exposed to.
- Full Text:
- Date Issued: 2004
- Authors: Rust, Nico
- Date: 2004
- Subjects: Polypropylene , Lead-acid batteries
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10978 , http://hdl.handle.net/10948/269 , Polypropylene , Lead-acid batteries
- Description: Polypropylene has proven to be the ideal material for the outer shell of the lead acid batteries. Due to its mold-ability and inert properties the material provides a capsule for the functioning components of the lead acid battery and can withstand a variety conditions encountered during its application, such as impact shock resistance, high and low temperatures and acid resistance. Polypropylene has however become of great concern with regards to environmental pollution since it is generally resistant to normal conditions of degradation and can only be properly disposed of by incineration. This factor has encouraged the industry to find ways to regenerate spent polypropylene. A good example of such a process is the recycling of lead acid batteries. This allows not only for the regeneration of lead, but also for the recycling of polypropylene in the manufacturing of battery cases. There are some cost advantages in using recycled polypropylene. However it does have its disadvantages in that the material does start to deteriorate after multiple processes. A common practice amongst battery manufacturers is to add virgin polypropylene to the recycled material in order to ensure performance consistency. The comparative study investigated the use of various ratios of virgin and recycled PP in the manufacturing of lead acid battery cases and their influence on the physical properties and performance of the final material. The degradation of PP was also investigated as the material was subjected to multiple manufacturing processes where the influence of stabilizers was further considered. A common technique of PP analysis such as MFI was shown to be an effective technique to maintain good quality control. The study further showed that it is important that the material grade of PP used in the manufacturing of the battery case and lid is compatible in order to allow for effective heating sealing of the two components. Polypropylene has a waxy surface finish and it is generally difficult to label or write on. Labels tend to fall off in application and make it difficult to maintain a track record of the manufactured batteries with time. This study showed successfully that a laser activated dye can be added to the PP without influencing its color or its performance. This allows for successful labeling of battery cases by various bar coding writers that can trace the battery through its manufacturing process. Lead acid batteries are often operated outside the specified temperature range that is determined by battery manufacturers resulting in premature failure. These failures can occur within the warranty period of the battery and result in illicit claims since the monitoring of the batteries in its application was not possible. A suitable temperature monitoring device was designed that would be incorporated into the vent cap or lid of the battery case. The device contained temperature sensitive indicators that would undergo a permanent color change at specified temperatures thereby giving the battery manufacturer an indication as to the maximum temperature the battery was exposed to.
- Full Text:
- Date Issued: 2004
The use of computer-based management information systems as a recruitment tool an assessment of the attitudes of recruitment agents in a selected area of the Western Cape on 10 February 2004
- Authors: Victor, Louana
- Date: 2004
- Subjects: Employment agencies -- South Africa -- Western Cape -- Evaluation , Employee selection -- South Africa -- Western Cape -- Data processing , Management information systems -- South Africa -- Western Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10997 , http://hdl.handle.net/10948/342 , Employment agencies -- South Africa -- Western Cape -- Evaluation , Employee selection -- South Africa -- Western Cape -- Data processing , Management information systems -- South Africa -- Western Cape
- Description: Recruitment and selection has become a specialised industry and is competing in a global market. To remain competitive, recruitment agents have to stay ahead of their competitors, by providing an excellent service to customers and applicants, and by keeping up with technological developments in their field. The current investigation focuses on an assessment of the attitudes of recruitment agents in a selected area of the Western Cape Province to the use of computer-based management information systems as a recruitment tool. A questionnaire was distributed amongst recruitment agents in the identified area. It focused on recruiter biographical information, the services they offer, the methods and processes they use in recruitment, the knowledge and skills they need in their field, and their knowledge and attitude towards electronic-recruitment. The literature indicated a move towards using technology in the field of recruitment, and this was consistent with the findings of the study. Although the respondents were familiar with developments in technology used for recruitment, only a small number were familiar with the major business information systems, namely, SAP R/3, Oracle and PeopleSoft. Information specifically related to recruitment agents in South Africa was limited, but the study provided some insight into this field. It was found that recruitment agents disagree on what a good advertisement, as well as a good résumé, should contain, and this is problematic as these are two of the most important things that recruitment agents work with every day. The literature provided no indication of the qualifications needed by a recruitment agent, and resulting from this, a second finding of the study indicated that, according to the respondents, the qualifications needed by a recruitment agent are varied. It was found that qualifications of the sample group varied from only a school-leaving certificate to post-graduate degrees. A significant trend identified that only 24.2 per cent of recruitment agents are involved in research related to recruitment, and write articles related to their field. This contributes to the fact that so little information is available about South African recruitment agents. The study indicated that recruitment agents hold a positive attitude towards computer-based information systems, although they are accepted with caution because of various logistical problems in the South African market. The study also provided useful information to start a process of drawing up a profile of the South African recruitment agency business.
- Full Text:
- Date Issued: 2004
- Authors: Victor, Louana
- Date: 2004
- Subjects: Employment agencies -- South Africa -- Western Cape -- Evaluation , Employee selection -- South Africa -- Western Cape -- Data processing , Management information systems -- South Africa -- Western Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10997 , http://hdl.handle.net/10948/342 , Employment agencies -- South Africa -- Western Cape -- Evaluation , Employee selection -- South Africa -- Western Cape -- Data processing , Management information systems -- South Africa -- Western Cape
- Description: Recruitment and selection has become a specialised industry and is competing in a global market. To remain competitive, recruitment agents have to stay ahead of their competitors, by providing an excellent service to customers and applicants, and by keeping up with technological developments in their field. The current investigation focuses on an assessment of the attitudes of recruitment agents in a selected area of the Western Cape Province to the use of computer-based management information systems as a recruitment tool. A questionnaire was distributed amongst recruitment agents in the identified area. It focused on recruiter biographical information, the services they offer, the methods and processes they use in recruitment, the knowledge and skills they need in their field, and their knowledge and attitude towards electronic-recruitment. The literature indicated a move towards using technology in the field of recruitment, and this was consistent with the findings of the study. Although the respondents were familiar with developments in technology used for recruitment, only a small number were familiar with the major business information systems, namely, SAP R/3, Oracle and PeopleSoft. Information specifically related to recruitment agents in South Africa was limited, but the study provided some insight into this field. It was found that recruitment agents disagree on what a good advertisement, as well as a good résumé, should contain, and this is problematic as these are two of the most important things that recruitment agents work with every day. The literature provided no indication of the qualifications needed by a recruitment agent, and resulting from this, a second finding of the study indicated that, according to the respondents, the qualifications needed by a recruitment agent are varied. It was found that qualifications of the sample group varied from only a school-leaving certificate to post-graduate degrees. A significant trend identified that only 24.2 per cent of recruitment agents are involved in research related to recruitment, and write articles related to their field. This contributes to the fact that so little information is available about South African recruitment agents. The study indicated that recruitment agents hold a positive attitude towards computer-based information systems, although they are accepted with caution because of various logistical problems in the South African market. The study also provided useful information to start a process of drawing up a profile of the South African recruitment agency business.
- Full Text:
- Date Issued: 2004
The use of environmental learning support materials to mediate learning in outcomes-based education: a case study in an Eastern Cape school
- Authors: Nduna, Nomalungelo Rosement
- Date: 2004
- Subjects: Environmental education -- South Africa -- Eastern Cape Environmental education -- Curricula -- South Africa Teaching -- Aids and devices -- South Africa Environmental education -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1812 , http://hdl.handle.net/10962/d1003698
- Description: Educational transformation and curriculum reform within the new South African Outcomes Based Education (OBE) system has introduced new roles for teachers, and a focus on environmental learning within each learning area. In an OBE system, teachers are required to mediate learning, develop learning programmes, and use a range of different learning support materials. This study aimed to explore how one teacher in an Eastern Cape school used environmental learning support materials to mediate learning within an OBE curriculum framework. Over the past ten years a number of environmental educators and researchers have been participating in curriculum policy development and curriculum implementation research. This has led to the incorporation of an environmental focus within different learning areas in Curriculum 2005. The focus on environment in the curriculum was strengthened by the introduction of the National Environmental Education Project in the General Education and Training (NEEP-GET) band in 2001. I am employed as a provincial co-coordinator within this project (for the Eastern Cape province), and one of my tasks is to work with service providers (who provide learning support materials) and teachers (who use these materials) to ensure improved environmental learning within the OBE curriculum. A qualitative and empirical case study was conducted in which I observed one teacher in a multi-grade class (with grade 6 and 7 learners) using learning support materials to achieve learning outcomes in three different lessons. The study employed a range of data collection methods such as questionnaires, interviews, field notes, video recording, and document analysis, photographs and journal entries. I compiled a contextual profile of the school and classroom and undertook two 'layers' of data analysis to report the findings of the study. This research indicates that theories of learning and associated teaching methods influence learning interactions, and the use of learning support material in the class. The study also highlighted emerging issues in the use of environmental learning support materials, which relate to planning; access to materials; over-use of materials; and the relationship between learning support materials and teaching methods.
- Full Text:
- Date Issued: 2004
- Authors: Nduna, Nomalungelo Rosement
- Date: 2004
- Subjects: Environmental education -- South Africa -- Eastern Cape Environmental education -- Curricula -- South Africa Teaching -- Aids and devices -- South Africa Environmental education -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1812 , http://hdl.handle.net/10962/d1003698
- Description: Educational transformation and curriculum reform within the new South African Outcomes Based Education (OBE) system has introduced new roles for teachers, and a focus on environmental learning within each learning area. In an OBE system, teachers are required to mediate learning, develop learning programmes, and use a range of different learning support materials. This study aimed to explore how one teacher in an Eastern Cape school used environmental learning support materials to mediate learning within an OBE curriculum framework. Over the past ten years a number of environmental educators and researchers have been participating in curriculum policy development and curriculum implementation research. This has led to the incorporation of an environmental focus within different learning areas in Curriculum 2005. The focus on environment in the curriculum was strengthened by the introduction of the National Environmental Education Project in the General Education and Training (NEEP-GET) band in 2001. I am employed as a provincial co-coordinator within this project (for the Eastern Cape province), and one of my tasks is to work with service providers (who provide learning support materials) and teachers (who use these materials) to ensure improved environmental learning within the OBE curriculum. A qualitative and empirical case study was conducted in which I observed one teacher in a multi-grade class (with grade 6 and 7 learners) using learning support materials to achieve learning outcomes in three different lessons. The study employed a range of data collection methods such as questionnaires, interviews, field notes, video recording, and document analysis, photographs and journal entries. I compiled a contextual profile of the school and classroom and undertook two 'layers' of data analysis to report the findings of the study. This research indicates that theories of learning and associated teaching methods influence learning interactions, and the use of learning support material in the class. The study also highlighted emerging issues in the use of environmental learning support materials, which relate to planning; access to materials; over-use of materials; and the relationship between learning support materials and teaching methods.
- Full Text:
- Date Issued: 2004
The value of many small vs. few large marine protected areas in the Western Solomon Islands
- Shankar, Aswani, Hamilton, Richard
- Authors: Shankar, Aswani , Hamilton, Richard
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440050 , vital:73731
- Description: Scientists and policy makers are universally promoting marine protected areas (MPAs) as a fisheries and ecosystem management tool. Experts generally agree that MPAs, particularly fully protected “no-take” zones, can enhance spawning stock biomass, allow for larval dispersal and the export of adults to adjacent non-protected areas, maintain species diversity, preserve habitat, and sustain ecosystem function (eg Bergen and Carr 2003; Johnson et al. 1999; Russ and Alcala 1999). In the case of tropical multi-species fisheries, in which absolute yields are difficult to predict and in which there are multiple users and fishing techniques, marine reserves also can act as precautionary tools to prevent overexploitation. Considering that orthodox fisheries management strategies have generally failed to prevent overfishing globally, the inception of MPAs as a management tool is of particular preventive significance (Russ 2002). Proponents of MPAs have broadly debated the appropriate size and number of MPAs that should be established in order to produce what a particular management prescription proposes to deliver. Some scientists argue that for MPAs to be effective they should cover areas in the magnitude of hundreds or even thousands of square miles, depending upon the type of environment (eg Beattie et al. 2002; Man et al. 1995; Walters 2000). Others have suggested that from a fisheries enhancement perspective, many small reserves in a network are preferred over fewer, larger reserves (eg Roberts et al. 2003). Other debates have centred on how much attention should be paid to science-driven vs. stakeholder-driven considerations when designing MPAs (eg Agardy 1997; Alder et al. 2002; Christie et al. 2003; Jones 2002).
- Full Text:
- Date Issued: 2004
- Authors: Shankar, Aswani , Hamilton, Richard
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440050 , vital:73731
- Description: Scientists and policy makers are universally promoting marine protected areas (MPAs) as a fisheries and ecosystem management tool. Experts generally agree that MPAs, particularly fully protected “no-take” zones, can enhance spawning stock biomass, allow for larval dispersal and the export of adults to adjacent non-protected areas, maintain species diversity, preserve habitat, and sustain ecosystem function (eg Bergen and Carr 2003; Johnson et al. 1999; Russ and Alcala 1999). In the case of tropical multi-species fisheries, in which absolute yields are difficult to predict and in which there are multiple users and fishing techniques, marine reserves also can act as precautionary tools to prevent overexploitation. Considering that orthodox fisheries management strategies have generally failed to prevent overfishing globally, the inception of MPAs as a management tool is of particular preventive significance (Russ 2002). Proponents of MPAs have broadly debated the appropriate size and number of MPAs that should be established in order to produce what a particular management prescription proposes to deliver. Some scientists argue that for MPAs to be effective they should cover areas in the magnitude of hundreds or even thousands of square miles, depending upon the type of environment (eg Beattie et al. 2002; Man et al. 1995; Walters 2000). Others have suggested that from a fisheries enhancement perspective, many small reserves in a network are preferred over fewer, larger reserves (eg Roberts et al. 2003). Other debates have centred on how much attention should be paid to science-driven vs. stakeholder-driven considerations when designing MPAs (eg Agardy 1997; Alder et al. 2002; Christie et al. 2003; Jones 2002).
- Full Text:
- Date Issued: 2004
The viability of small-scale farming at the Tyhefu Irrigation Scheme, Eastern Cape
- Authors: Sishuta, Happy Babalwa
- Date: 2004
- Subjects: Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3344 , http://hdl.handle.net/10962/d1004924 , Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Description: This investigation is conducted against the background of current attempts to rehabilitate and revive the now defunct Tyhefu irrigation scheme. The poor track record of many irrigation schemes (despite huge investments) in the former homelands has prompted the government to reconsider its active and direct role in small-scale irrigation farming. This has resulted in the closure of many irrigation schemes including Tyhefu irrigation scheme. The new policy framework in South Africa, known as the irrigation management transfer, is premised on the transfer of ownership, authority and responsibility of small-scale irrigation schemes from government to the farmers. Tyhefu irrigation scheme was a state-driven, top-down initiative. This study argues that the justifications for the Tyhefu irrigation scheme were conflated, with the result that the need for political control of the Tyhefu area far outweighed the considerations regarding the financial viability and sustainability of the proposed project. Given the repressive political climate of the time in South Africa, the planners' proposals were a mechanism for the realization of the socio-political and economic agendas of the apartheid state and Ciskei government. Although technical factors critical for project success were examined, little or no attention was paid to the socio-economic aspects. For the planners, the main requirements for success entailed centralized managerial control, no participation of the beneficiaries, capital intensive and sophisticated agricultural techniques and the production of high value crops. Therefore, it can be argued that the nature of the planning and implementation of the Tyhefu irrigation scheme was ill-conceived, short-sighted and misguided. A review of the literature on irrigation development on the African continent provided useful insights for this study. The lessons from irrigation development experience in Sub-Saharan Africa indicate that the continent is littered with examples of derelict and costly failures. What stands out in many of these irrigation projects is their over-emphasis on technical issues to the complete neglect of human and other social aspects. Working partnerships between the farmers and irrigation scheme management could, thus, not be realized. Almost without exception the case studies used here indicate that the industrious type of farmer was never developed as was envisioned in the planning documents. Neither were rural livelihoods improved in a sustainable manner. The findings of this study suggest that irrigation management transfer is a complex and delicate process. In this new set of arrangements, beneficiaries face formidable challenges in terms of capacity (human and financial) if small-scale irrigation farming is to become a viable sector. No doubt, the viability and sustainability of the Tyhefu irrigation scheme demands a comprehensive package of interventions that address various issues of markets and marketing, capital investment and access to finance, technology, education and training, support and extension services. It is evident that institutional aspects and the related issue of functional literacy require much more attention than thus far. As a result, at the moment there is no possibility for independent agricultural production. , KMBT_363
- Full Text:
- Date Issued: 2004
- Authors: Sishuta, Happy Babalwa
- Date: 2004
- Subjects: Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3344 , http://hdl.handle.net/10962/d1004924 , Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Description: This investigation is conducted against the background of current attempts to rehabilitate and revive the now defunct Tyhefu irrigation scheme. The poor track record of many irrigation schemes (despite huge investments) in the former homelands has prompted the government to reconsider its active and direct role in small-scale irrigation farming. This has resulted in the closure of many irrigation schemes including Tyhefu irrigation scheme. The new policy framework in South Africa, known as the irrigation management transfer, is premised on the transfer of ownership, authority and responsibility of small-scale irrigation schemes from government to the farmers. Tyhefu irrigation scheme was a state-driven, top-down initiative. This study argues that the justifications for the Tyhefu irrigation scheme were conflated, with the result that the need for political control of the Tyhefu area far outweighed the considerations regarding the financial viability and sustainability of the proposed project. Given the repressive political climate of the time in South Africa, the planners' proposals were a mechanism for the realization of the socio-political and economic agendas of the apartheid state and Ciskei government. Although technical factors critical for project success were examined, little or no attention was paid to the socio-economic aspects. For the planners, the main requirements for success entailed centralized managerial control, no participation of the beneficiaries, capital intensive and sophisticated agricultural techniques and the production of high value crops. Therefore, it can be argued that the nature of the planning and implementation of the Tyhefu irrigation scheme was ill-conceived, short-sighted and misguided. A review of the literature on irrigation development on the African continent provided useful insights for this study. The lessons from irrigation development experience in Sub-Saharan Africa indicate that the continent is littered with examples of derelict and costly failures. What stands out in many of these irrigation projects is their over-emphasis on technical issues to the complete neglect of human and other social aspects. Working partnerships between the farmers and irrigation scheme management could, thus, not be realized. Almost without exception the case studies used here indicate that the industrious type of farmer was never developed as was envisioned in the planning documents. Neither were rural livelihoods improved in a sustainable manner. The findings of this study suggest that irrigation management transfer is a complex and delicate process. In this new set of arrangements, beneficiaries face formidable challenges in terms of capacity (human and financial) if small-scale irrigation farming is to become a viable sector. No doubt, the viability and sustainability of the Tyhefu irrigation scheme demands a comprehensive package of interventions that address various issues of markets and marketing, capital investment and access to finance, technology, education and training, support and extension services. It is evident that institutional aspects and the related issue of functional literacy require much more attention than thus far. As a result, at the moment there is no possibility for independent agricultural production. , KMBT_363
- Full Text:
- Date Issued: 2004
The wing coupling apparatus and the morphometric analysis of honeybee populations
- Hepburn, H Randall, Radloff, Sarah E
- Authors: Hepburn, H Randall , Radloff, Sarah E
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6904 , http://hdl.handle.net/10962/d1011760
- Description: Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used.
- Full Text:
- Date Issued: 2004
- Authors: Hepburn, H Randall , Radloff, Sarah E
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6904 , http://hdl.handle.net/10962/d1011760
- Description: Significant differences between countries were found in the distribution of the number of hamuli within Apis andreniformis, A. florea, A. cerana and A. koschevnikovi. The mean hamuli numbers for Apis mellifera intermissa differed significantly among localities in Algeria. Significant differences in intercolonial variability between countries were found within A. cerana. There was no significant infraspecific variability within A. andreniformis, A. florea, A. koschevnikovi and A. m. intermissa. Significant differences in the mean number of hamuli occur between A. m. intermissa and A. andreniformis, A. florea and A. cerana; also between A. cerana/A. koschevnikovi and A. andreniformis and A. florea. Significant differences were found in the distribution and variability of the number of hamuli between species (populations). The mean numbers of hamuli for A. andreniformis differed from those of A. florea. Both these population means differed from those of A. cerana, A. koschevnikovi and A. m. intermissa. No significant differences were found between A. cerana and A. koschevnikovi. When the analysis included data for A. dorsata, A. nigrocincta, A. m. carnica, A. m. caucasica and A. m. ligustica, the results showed significant differences in hamuli numbers between A. andreniformis/A. florea and A. cerana/A. koschevnikovi/A. nigrocincta and A. m. intermissa/A. m. carnica/A. m. caucasica/A. m. ligustica. Hamuli numbers in A. dorsata significantly differed from those of other populations except A. m. intermissa. These results show that hamuli numbers are useful in the classification of honeybee populations. Whether hamuli would be useful in multivariate analysis depends on the correlation between the number of hamuli and the other characters used.
- Full Text:
- Date Issued: 2004
Thermal and photostability studies of triprolidine hydrochloride and its mixtures with cyclodextrin and glucose
- Authors: Ndlebe, Vuyelwa Jacqueline
- Date: 2004
- Subjects: Antihistamines , Glucose , Cyclodextrins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4387 , http://hdl.handle.net/10962/d1005052 , Antihistamines , Glucose , Cyclodextrins
- Description: Triprolidine hydrochloride (C₁₉H₂₂N₂.HCl.H₂O) (TPH) is a well-known antihistamine drug. It melts between 118°C and 122°C and the amount of water present is 4.5 mass percent. TPH is reported as being photosensitive and must be stored in sealed, light-tight containers. The thermal stabilities of TPH and of 1:1 molar and 1:1 mass ratio physical mixtures of TPH with beta-cyclodextrin (BCD) and with glucose have been examined using DSC, TG and TG-FTIR, complemented by X-ray powder diffraction (XRD) and infrared spectroscopic (IR) studies. Thermal studies of the solid TPH/BCD mixtures indicated that interaction between the components occurs and it is possible that the TPH molecule may be least partially accommodated in the cavity of the BCD host molecule. XRD results support this indication of inclusion. The results for mixtures of TPH/glucose also suggest that there is interaction between the two components. The results of molecular modelling suggest that TPH is most likely to be accommodated in the BCD cavity as a neutral triprolidine molecule with the toluene portion of the molecule entering first. There is also an indication that the Z-isomer should be accommodated slightly more readily than the E-isomer. Photostability studies were done by irradiating thin layers of solid samples of TPH and its mixtures for various times at 40°C using an Atlas Sun test CPS lamp operating at 550 W h m⁻². An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants. The results obtained illustrate the general stability of TPH, especially in the solid state. Although the potential for isomerization to the pharmaceutically inactive Z-isomer exists, this transformation would require extreme light conditions. The study has also shown TPH to be compatible with both glucose and BCD, which are potential excipients both in solid and liquid dosage forms. The presents of these excipients in dosage forms will thus not adversely affect the stability and the therapeutic efficacy of TPH. . An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants.
- Full Text:
- Date Issued: 2004
- Authors: Ndlebe, Vuyelwa Jacqueline
- Date: 2004
- Subjects: Antihistamines , Glucose , Cyclodextrins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4387 , http://hdl.handle.net/10962/d1005052 , Antihistamines , Glucose , Cyclodextrins
- Description: Triprolidine hydrochloride (C₁₉H₂₂N₂.HCl.H₂O) (TPH) is a well-known antihistamine drug. It melts between 118°C and 122°C and the amount of water present is 4.5 mass percent. TPH is reported as being photosensitive and must be stored in sealed, light-tight containers. The thermal stabilities of TPH and of 1:1 molar and 1:1 mass ratio physical mixtures of TPH with beta-cyclodextrin (BCD) and with glucose have been examined using DSC, TG and TG-FTIR, complemented by X-ray powder diffraction (XRD) and infrared spectroscopic (IR) studies. Thermal studies of the solid TPH/BCD mixtures indicated that interaction between the components occurs and it is possible that the TPH molecule may be least partially accommodated in the cavity of the BCD host molecule. XRD results support this indication of inclusion. The results for mixtures of TPH/glucose also suggest that there is interaction between the two components. The results of molecular modelling suggest that TPH is most likely to be accommodated in the BCD cavity as a neutral triprolidine molecule with the toluene portion of the molecule entering first. There is also an indication that the Z-isomer should be accommodated slightly more readily than the E-isomer. Photostability studies were done by irradiating thin layers of solid samples of TPH and its mixtures for various times at 40°C using an Atlas Sun test CPS lamp operating at 550 W h m⁻². An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants. The results obtained illustrate the general stability of TPH, especially in the solid state. Although the potential for isomerization to the pharmaceutically inactive Z-isomer exists, this transformation would require extreme light conditions. The study has also shown TPH to be compatible with both glucose and BCD, which are potential excipients both in solid and liquid dosage forms. The presents of these excipients in dosage forms will thus not adversely affect the stability and the therapeutic efficacy of TPH. . An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants.
- Full Text:
- Date Issued: 2004
Three decades of hydrological modelling research in South Africa
- Authors: Hughes, Denis A
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:7072 , http://hdl.handle.net/10962/d1009526
- Description: This paper presents a review of the research undertaken in the field of hydrological modelling over roughly the last three decades, concentrating primarily on South African work in an international context. The focus is on deterministic, rainfall-runoff models and addresses issues related to model design as well as to the application of models in practice. I provide a brief description of what hydrological models are and what they are used for and discuss also the following issues: • Developments in understanding hydrological process and the extent to which these have filtered down into models. • Model calibration and parameter estimation. • Trends in data availability and how these have affected model development. • Trends in computer technology and their impacts on model development. I suggest that there have been substantial developments in the science and practice of hydrological modelling, but that there remain many problems that need to be addressed to improve the ability of models to contribute to the solution of problems of water resource management. Southern African scientists have contributed to the body of knowledge on hydrological modelling, despite the limited resources available compared to resources elsewhere. Internationally, the focus has not always been on the practical issues of model application and has commonly tended towards the more theoretical and mathematical issues of model calibration. This is not a trend that has found much favour in southern Africa (particularly amongst research funding agencies), where there are many problems of water resource management that have the potential to be resolved with existing models, applied in an appropriate way. The paper concludes by suggesting that further research needs to focus on the integration of the best in international developments with the tried and tested models that have been developed locally. The context of this research should be the search for more reliable estimations of water resource availability.
- Full Text:
- Date Issued: 2004
- Authors: Hughes, Denis A
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:7072 , http://hdl.handle.net/10962/d1009526
- Description: This paper presents a review of the research undertaken in the field of hydrological modelling over roughly the last three decades, concentrating primarily on South African work in an international context. The focus is on deterministic, rainfall-runoff models and addresses issues related to model design as well as to the application of models in practice. I provide a brief description of what hydrological models are and what they are used for and discuss also the following issues: • Developments in understanding hydrological process and the extent to which these have filtered down into models. • Model calibration and parameter estimation. • Trends in data availability and how these have affected model development. • Trends in computer technology and their impacts on model development. I suggest that there have been substantial developments in the science and practice of hydrological modelling, but that there remain many problems that need to be addressed to improve the ability of models to contribute to the solution of problems of water resource management. Southern African scientists have contributed to the body of knowledge on hydrological modelling, despite the limited resources available compared to resources elsewhere. Internationally, the focus has not always been on the practical issues of model application and has commonly tended towards the more theoretical and mathematical issues of model calibration. This is not a trend that has found much favour in southern Africa (particularly amongst research funding agencies), where there are many problems of water resource management that have the potential to be resolved with existing models, applied in an appropriate way. The paper concludes by suggesting that further research needs to focus on the integration of the best in international developments with the tried and tested models that have been developed locally. The context of this research should be the search for more reliable estimations of water resource availability.
- Full Text:
- Date Issued: 2004
Timing of moult and breeding in the Cape White-eye, Zosterops pallidus, from three different geographical regions in South Africa
- Hulley, Patrick E, Craig, Adrian J F K, Underhill, George D, Bonnevie, Bo T, Nuttall, R J, De Swardt, D H
- Authors: Hulley, Patrick E , Craig, Adrian J F K , Underhill, George D , Bonnevie, Bo T , Nuttall, R J , De Swardt, D H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465570 , vital:76621 , https://doi.org/10.1071/MU03055
- Description: Cape White-eyes are widespread in South Africa, occurring in different climatic regions. We analysed primary moult data for large samples of this species from three geographical regions. There were no apparent long-term changes in duration or timing of moult during the nine years that the Western Cape results were collected, but sites within this region had different mean starting dates for primary moult. The Eastern Cape and Free State birds began moult about a month later than those in the Western Cape. This correlated well with the earlier breeding season in the Western Cape, and there was no evidence of overlap between moult and breeding. Mean primary moult duration was not significantly different among the sites or regions, and may be a species-specific trait. There was no evidence of regular long-distance movements in this species.
- Full Text:
- Date Issued: 2004
- Authors: Hulley, Patrick E , Craig, Adrian J F K , Underhill, George D , Bonnevie, Bo T , Nuttall, R J , De Swardt, D H
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465570 , vital:76621 , https://doi.org/10.1071/MU03055
- Description: Cape White-eyes are widespread in South Africa, occurring in different climatic regions. We analysed primary moult data for large samples of this species from three geographical regions. There were no apparent long-term changes in duration or timing of moult during the nine years that the Western Cape results were collected, but sites within this region had different mean starting dates for primary moult. The Eastern Cape and Free State birds began moult about a month later than those in the Western Cape. This correlated well with the earlier breeding season in the Western Cape, and there was no evidence of overlap between moult and breeding. Mean primary moult duration was not significantly different among the sites or regions, and may be a species-specific trait. There was no evidence of regular long-distance movements in this species.
- Full Text:
- Date Issued: 2004
To investigate the effect of a change in hard gelatin capsule supplier on a phenytoin sodium capsule formulation
- Authors: Marx, Amor
- Date: 2004
- Subjects: Capsules (Pharmacy) , Phenytoin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10984 , http://hdl.handle.net/10948/265 , Capsules (Pharmacy) , Phenytoin
- Description: Stability studies were undertaken at ambient (25ºC/60%RH) and accelerated conditions (40ºC/75%RH) to determine the effect of changing of hard gelatin capsule supplier on a phenytoin sodium (100 mg) capsule formulation. Three hard gelatin capsule suppliers: RP Scherer (Supplier A), Capsugel (supplier B) and Associated Caps (Supplier C) were used in the study. Capsules were analyzed just after filling of the capsules (T0), after 1 month (T1), after 2 months (T2) and after 3 months (T3) after being stored in securitainers under the above-mentioned conditions. The moisture content of the empty shells as well as the capsule contents were analysed at each time-point. The capsule disintegration time was recorded at each time point. Multi-point dissolution testing was performed at each time point to determine the release of the active substance in each case. Based on the achieved results, the best capsule shell supplier was recommended, and other suggestions were made to improve the capsule formulation.
- Full Text:
- Date Issued: 2004
- Authors: Marx, Amor
- Date: 2004
- Subjects: Capsules (Pharmacy) , Phenytoin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10984 , http://hdl.handle.net/10948/265 , Capsules (Pharmacy) , Phenytoin
- Description: Stability studies were undertaken at ambient (25ºC/60%RH) and accelerated conditions (40ºC/75%RH) to determine the effect of changing of hard gelatin capsule supplier on a phenytoin sodium (100 mg) capsule formulation. Three hard gelatin capsule suppliers: RP Scherer (Supplier A), Capsugel (supplier B) and Associated Caps (Supplier C) were used in the study. Capsules were analyzed just after filling of the capsules (T0), after 1 month (T1), after 2 months (T2) and after 3 months (T3) after being stored in securitainers under the above-mentioned conditions. The moisture content of the empty shells as well as the capsule contents were analysed at each time-point. The capsule disintegration time was recorded at each time point. Multi-point dissolution testing was performed at each time point to determine the release of the active substance in each case. Based on the achieved results, the best capsule shell supplier was recommended, and other suggestions were made to improve the capsule formulation.
- Full Text:
- Date Issued: 2004
Towards a better understanding of information systems strategy options and its link with business strategy
- Authors: Buchanan, Darryl Vaughn
- Date: 2004
- Subjects: Management information systems , Strategic planning -- Data processing , Information technology -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10864 , http://hdl.handle.net/10948/267 , Management information systems , Strategic planning -- Data processing , Information technology -- Management
- Description: There is considerable evidence that the strategic use of Information Systems can lead to a competitive advantage. There is however, a marked lack of understanding of the options available, as well as the smooth coordination of Information Systems strategy with Business strategy. This paper provides insight into the role of Information Systems and its link with business strategy. It focuses on Information Systems strategy options, and explores the criteria needed for successful Information Systems strategy and Business strategy alignment. The paper presents and examines the results of a study of strategic alignment at Volkswagen of South Africa. Data was obtained from business and Information Technology executives. The result of the study enables Volkswagen not only to benchmark themselves, but also provides direction to enable successful business/IT alignment. It identifies specific actions necessary to ensure that IT is being used to appropriately enable or drive the business strategy.
- Full Text:
- Date Issued: 2004
- Authors: Buchanan, Darryl Vaughn
- Date: 2004
- Subjects: Management information systems , Strategic planning -- Data processing , Information technology -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10864 , http://hdl.handle.net/10948/267 , Management information systems , Strategic planning -- Data processing , Information technology -- Management
- Description: There is considerable evidence that the strategic use of Information Systems can lead to a competitive advantage. There is however, a marked lack of understanding of the options available, as well as the smooth coordination of Information Systems strategy with Business strategy. This paper provides insight into the role of Information Systems and its link with business strategy. It focuses on Information Systems strategy options, and explores the criteria needed for successful Information Systems strategy and Business strategy alignment. The paper presents and examines the results of a study of strategic alignment at Volkswagen of South Africa. Data was obtained from business and Information Technology executives. The result of the study enables Volkswagen not only to benchmark themselves, but also provides direction to enable successful business/IT alignment. It identifies specific actions necessary to ensure that IT is being used to appropriately enable or drive the business strategy.
- Full Text:
- Date Issued: 2004
Towards an extended enterprise through e-Business integration
- Authors: Mostert, Nicolette
- Date: 2004
- Subjects: Enterprise application integration (Computer systems) , Electronic commerce , Business enterprises -- Data processing
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10803 , http://hdl.handle.net/10948/268 , Enterprise application integration (Computer systems) , Electronic commerce , Business enterprises -- Data processing
- Description: The focus of this project will be on introducing the concept of an extended enterprise to business leaders, subsequently presenting e- Business Integration and the supporting role that it can play in the establishment of an extended enterprise. Various literature sources will be consolidated to describe the integration approaches and supporting integration technologies and standards that can be employed in establishing integrated communication between the members of the extended enterprise. Finally, a phased approach will be proposed that can be employed in supporting the establishment of an extended enterprise through e-Business Integration.
- Full Text:
- Date Issued: 2004
- Authors: Mostert, Nicolette
- Date: 2004
- Subjects: Enterprise application integration (Computer systems) , Electronic commerce , Business enterprises -- Data processing
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10803 , http://hdl.handle.net/10948/268 , Enterprise application integration (Computer systems) , Electronic commerce , Business enterprises -- Data processing
- Description: The focus of this project will be on introducing the concept of an extended enterprise to business leaders, subsequently presenting e- Business Integration and the supporting role that it can play in the establishment of an extended enterprise. Various literature sources will be consolidated to describe the integration approaches and supporting integration technologies and standards that can be employed in establishing integrated communication between the members of the extended enterprise. Finally, a phased approach will be proposed that can be employed in supporting the establishment of an extended enterprise through e-Business Integration.
- Full Text:
- Date Issued: 2004
Towards sustainable utilisation of the fishery resources of the Kowie Estuary, South Africa
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2004
- Subjects: Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4761 , http://hdl.handle.net/10962/d1007154 , Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Description: The annual biomass of fish caught from estuaries in South Africa is currently estimated at over 24,800 tons. These estuarine fishes are caught by over 73,000 fishers, most of them recreational. Annual income derived from South Africa’s total estuarine fishery was worth approximately R430,000,000 in 1997. There is increasing concern that unless our estuarine fisheries are effectively managed, we will not be able to sustain these benefits into the future. Two factors that contribute to inadequate management of the estuarine fisheries in South Africa are a lack of data on which to base management decisions, and the lack of indicators by which to assess trends towards sustainability. The main aims of this study were to provide a description of the Kowie estuary fishery, identify suitable indicators of sustainability for this fishery, and assess its sustainability. Boat-based and shore-based roving creel surveys were carried out on the Kowie estuary between July 2000 and June 2001; 1,091 interviews were conducted with linefishers, and 277 interviews with bait collectors. In the boat-based interviews, data were collected on fisher demographics, fishing site, fishing method, choice of bait, fishing duration and catch statistics. In the shore-based surveys, additional data were collected from shore-based linefishers and bait collectors on their perceptions, attitudes, and knowledge of fishery regulations. Total annual fishing effort on the Kowie estuary was estimated at 30,952 angler hours (SD=154); 84% of it recreational, and the rest subsistence. Most fishing occurred during December and January, and decreased during winter, especially June and July. The annual yield of fish from the estuary was estimated at 16,240 fish (SD=667) or 5.99 tons (SD=0.81). By number, recreational anglers caught 69% of the annual catch. Three species dominated the catch by number: Rhabdosargus holubi (62%), Pomadasys commersonnii (17%) and Argyrosomus japonicus (7%). By mass, the dominant species caught were Argyrosomus japonicus (60%) and Pomadasys commersonnii (19%). Overall catch rate on the estuary was 0.57 fish.ang.⁻¹h⁻¹ (SD=0.24), or 0.298 kg ang.⁻¹h⁻¹ (SD=0.31). Overall catch rate by number was highest in the subsistence sector at 1.13 fish.ang.⁻¹h⁻¹(SD=0.70), while the boat-based recreational sector recorded the highest overall catch rate by mass (0.427 kg.ang.⁻¹h⁻¹, SD=0.625). Argyrosomus japonicus had the highest overall catch rate by mass on the estuary (0.496 kg ang.⁻¹h⁻¹), and Rhabdosargus holubi the highest overall catch rate by number (1.233 fish.ang.⁻¹h⁻¹). Only 19% of the catch of R. holubi was above the minimum legal size, while the estimates for P. commersonnii and A. japonicus were 21% and 25%, respectively. The annual number of bait collecting outings on the estuary was estimated at 2,889, of which 75% were subsistence. The highest numbers of bait collecting outings were recorded in December and April. The Bay of Biscay was the most popular site for bait collecting. A total of five invertebrate species were collected from the estuary to be used as bait, of which the mud prawn Upogebia africana was the dominant species. Total annual number of mud prawns collected from the estuary was estimated at 260,648; of which 41% was collected by subsistence bait collectors. Thirteen indicators were selected to assess sustainability in three fishery sectors on the Kowie estuary: namely, the shore-based recreational linefishery, the subsistence linefishery and the subsistence bait fishery. Social sustainability was evaluated on the basis of the use fishery resources to fulfil Maslow's basic human needs of food and employment, safety and security, affiliation, self-esteem and selfactualisation. Indicators of ecosystem sustainability assessed the productivity, diversity, disturbance and degree of water quality in the estuary. Institutional sustainability was assessed on the basis that management systems in the fishery should be results-oriented, consent-based, truth-seeking and adaptable. Data on indicator performance was collected during the shore-based roving creel survey, and from published literature. Arbitrarily set reference points were used to assess indicator performance, which was graded on a scale from 1 (indicating minimum probability of sustainability) to 4 (indicating maximum probability of sustainability). Sustainability was illustrated with the aid of amoeba plots. Overall sustainability was low in all three fishery sectors investigated. Nine of the 13 indicators in the shore-based recreational fishery performed poorly, while 11 of 13 in the subsistence line fishery, and 10 of 13 in the subsistence bait fishery, performed poorly. In all three fishery sectors all four selected indicators of institutional sustainability performed poorly. The probability of social sustainability was higher in the shore-based recreational line fishery, where the performance of two of the five selected indicators was very good. The probability of ecological sustainability was lowest in the shore-based recreational linefishery, while in the subsistence linefishery only one selected indicator performed very well. Recommendations made towards assessing sustainability in small-scale estuarine fisheries include the formulation of national policy for assessing sustainability in fisheries, the involvement of fishers in the assessment process, use of fisher perceptions where data gaps exist, and the use of research results to guide future management decisions. Management changes recommended for the Kowie estuary fishery include the formulation of an effective and integrated management plan, identification of the key stakeholders in the fishery, inclusion of fishers in management, the protection of the estuary’s Zostera capensis beds, and the establishment of a programme to increase research and monitoring in the fishery.
- Full Text:
- Date Issued: 2004
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2004
- Subjects: Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4761 , http://hdl.handle.net/10962/d1007154 , Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Description: The annual biomass of fish caught from estuaries in South Africa is currently estimated at over 24,800 tons. These estuarine fishes are caught by over 73,000 fishers, most of them recreational. Annual income derived from South Africa’s total estuarine fishery was worth approximately R430,000,000 in 1997. There is increasing concern that unless our estuarine fisheries are effectively managed, we will not be able to sustain these benefits into the future. Two factors that contribute to inadequate management of the estuarine fisheries in South Africa are a lack of data on which to base management decisions, and the lack of indicators by which to assess trends towards sustainability. The main aims of this study were to provide a description of the Kowie estuary fishery, identify suitable indicators of sustainability for this fishery, and assess its sustainability. Boat-based and shore-based roving creel surveys were carried out on the Kowie estuary between July 2000 and June 2001; 1,091 interviews were conducted with linefishers, and 277 interviews with bait collectors. In the boat-based interviews, data were collected on fisher demographics, fishing site, fishing method, choice of bait, fishing duration and catch statistics. In the shore-based surveys, additional data were collected from shore-based linefishers and bait collectors on their perceptions, attitudes, and knowledge of fishery regulations. Total annual fishing effort on the Kowie estuary was estimated at 30,952 angler hours (SD=154); 84% of it recreational, and the rest subsistence. Most fishing occurred during December and January, and decreased during winter, especially June and July. The annual yield of fish from the estuary was estimated at 16,240 fish (SD=667) or 5.99 tons (SD=0.81). By number, recreational anglers caught 69% of the annual catch. Three species dominated the catch by number: Rhabdosargus holubi (62%), Pomadasys commersonnii (17%) and Argyrosomus japonicus (7%). By mass, the dominant species caught were Argyrosomus japonicus (60%) and Pomadasys commersonnii (19%). Overall catch rate on the estuary was 0.57 fish.ang.⁻¹h⁻¹ (SD=0.24), or 0.298 kg ang.⁻¹h⁻¹ (SD=0.31). Overall catch rate by number was highest in the subsistence sector at 1.13 fish.ang.⁻¹h⁻¹(SD=0.70), while the boat-based recreational sector recorded the highest overall catch rate by mass (0.427 kg.ang.⁻¹h⁻¹, SD=0.625). Argyrosomus japonicus had the highest overall catch rate by mass on the estuary (0.496 kg ang.⁻¹h⁻¹), and Rhabdosargus holubi the highest overall catch rate by number (1.233 fish.ang.⁻¹h⁻¹). Only 19% of the catch of R. holubi was above the minimum legal size, while the estimates for P. commersonnii and A. japonicus were 21% and 25%, respectively. The annual number of bait collecting outings on the estuary was estimated at 2,889, of which 75% were subsistence. The highest numbers of bait collecting outings were recorded in December and April. The Bay of Biscay was the most popular site for bait collecting. A total of five invertebrate species were collected from the estuary to be used as bait, of which the mud prawn Upogebia africana was the dominant species. Total annual number of mud prawns collected from the estuary was estimated at 260,648; of which 41% was collected by subsistence bait collectors. Thirteen indicators were selected to assess sustainability in three fishery sectors on the Kowie estuary: namely, the shore-based recreational linefishery, the subsistence linefishery and the subsistence bait fishery. Social sustainability was evaluated on the basis of the use fishery resources to fulfil Maslow's basic human needs of food and employment, safety and security, affiliation, self-esteem and selfactualisation. Indicators of ecosystem sustainability assessed the productivity, diversity, disturbance and degree of water quality in the estuary. Institutional sustainability was assessed on the basis that management systems in the fishery should be results-oriented, consent-based, truth-seeking and adaptable. Data on indicator performance was collected during the shore-based roving creel survey, and from published literature. Arbitrarily set reference points were used to assess indicator performance, which was graded on a scale from 1 (indicating minimum probability of sustainability) to 4 (indicating maximum probability of sustainability). Sustainability was illustrated with the aid of amoeba plots. Overall sustainability was low in all three fishery sectors investigated. Nine of the 13 indicators in the shore-based recreational fishery performed poorly, while 11 of 13 in the subsistence line fishery, and 10 of 13 in the subsistence bait fishery, performed poorly. In all three fishery sectors all four selected indicators of institutional sustainability performed poorly. The probability of social sustainability was higher in the shore-based recreational line fishery, where the performance of two of the five selected indicators was very good. The probability of ecological sustainability was lowest in the shore-based recreational linefishery, while in the subsistence linefishery only one selected indicator performed very well. Recommendations made towards assessing sustainability in small-scale estuarine fisheries include the formulation of national policy for assessing sustainability in fisheries, the involvement of fishers in the assessment process, use of fisher perceptions where data gaps exist, and the use of research results to guide future management decisions. Management changes recommended for the Kowie estuary fishery include the formulation of an effective and integrated management plan, identification of the key stakeholders in the fishery, inclusion of fishers in management, the protection of the estuary’s Zostera capensis beds, and the establishment of a programme to increase research and monitoring in the fishery.
- Full Text:
- Date Issued: 2004
Towards the development of species-specific fish production models for small reservoirs in Southern Africa
- Authors: Potts, Warren M
- Date: 2004
- Subjects: Freshwater fishes -- Africa, Southern Fish populations -- Africa, Southern Fisheries -- Africa, Southern Sustainable fisheries -- Africa, Southern Labeo -- Reproduction Cyprinidae -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5330 , http://hdl.handle.net/10962/d1005176
- Description: The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.
- Full Text:
- Date Issued: 2004
- Authors: Potts, Warren M
- Date: 2004
- Subjects: Freshwater fishes -- Africa, Southern Fish populations -- Africa, Southern Fisheries -- Africa, Southern Sustainable fisheries -- Africa, Southern Labeo -- Reproduction Cyprinidae -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5330 , http://hdl.handle.net/10962/d1005176
- Description: The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.
- Full Text:
- Date Issued: 2004
Train to Alice
- Ncozana, J., Kese, E., Jafta, B. H., Mbeza, H. F., Hangana, S. A., Composer not specified, Dargie, Dave
- Authors: Ncozana, J. , Kese, E. , Jafta, B. H. , Mbeza, H. F. , Hangana, S. A. , Composer not specified , Dargie, Dave
- Date: 2004
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Alice sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343327 , vital:62996 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC344b-06
- Description: Song accompanied by guitar and various types of marimbas
- Full Text: false
- Date Issued: 2004
- Authors: Ncozana, J. , Kese, E. , Jafta, B. H. , Mbeza, H. F. , Hangana, S. A. , Composer not specified , Dargie, Dave
- Date: 2004
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Alice sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343327 , vital:62996 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC344b-06
- Description: Song accompanied by guitar and various types of marimbas
- Full Text: false
- Date Issued: 2004