Development and characterisation of a membrane gradostat bioreactor for the bioremediation of aromatic pollutants using white rot fungi
- Authors: Leukes, Winston D
- Date: 1999
- Subjects: Aromatic compounds Pollutants Fungi Bioremediation Industrial microbiology Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4032 , http://hdl.handle.net/10962/d1004092
- Description: Bioremediation of aromatic pollutants using the ligninolytic enzymes of the white rot fungi has been thoroughly researched and has been shown to have considerable potential for industrial application. However, little success in scale-up and industrialisation of this technology has been attained due to problems associated with the continuous production of the pollutant-degrading enzymes using conventional bioreactor systems. The low productivities reported result from the incompatibility of conventional submerged culture reactor techniques with the physiological requirements of these fungi which have evolved on a solid-air interface, viz. wood. The enzymes are also produced only during the stationary phase of growth and can therefore be regarded as secondary metabolites. This study reports the conceptualisation, characterisation and evaluation of a novel bioreactor system as a solution to the continuous production of idiophasic pollutant degrading enzymes by the white rot fungus Phanerochaete chlysosporium. The reactor concept evolved from observation of these fungi in their native state, i. e. the metabolism of lignocellulosic material and involves the immobilisation of the organism onto a capillary ultrafiltration membrane. Nutrient gradients established across the biofilm, an inherent characteristic of fixed bed perfusion reactors, are exploited to provide both nutrient rich and nutrient poor zones across the biofilm. This allows growth or primary metabolism in the nutrient rich zone, pushing older biomass into the nutrient poor zone where secondary metabolism is induced by nutrient starvation. In effect, this represents a transformation of the events of a batch culture from a temporal to a spatial domain, allowing continuous production of secondary metabolites over time. Direct contact of the outer part of the biofilm with an air stream simulated the solid-air interface of the native state of the fungus. In order to facilitate the practical application of the membrane gradostat reactor (MGR) concept, conventional capillary membranes and membrane bioreactor modules were first evaluated. These were found to be unsuitable for application of the MGR concept. However, critical analysis of the shortcomings of the conventional systems resulted in the formulation of a set of design criteria for the development of a suitable membrane and module. These design criteria were satisfied by the development of a novel capillary membrane for membrane bioreactors, as well as a transverse flow membrane module, which is a novel approach in membrane bioreactor configuration. For the physiological characterisation of the MGR concept, a single fibre bioreactor unit was designed, which allowed destructive sampling of the biofilm for analysis. Using this system, it was shown that distinct morphological zones could be observed radially across the mature biofilm obtained through MGR operation. That these morphotypes do represent the temporal events of a typical batch culture in a spatial domain was confirmed by following the morphological changes occurring during batch culture of the immobilised fungus where the onset of primary and secondary metabolic conditions were manipulated through control of the nutrient supply. The different morphotypes were correlated to distinct growth phases by comparison of the morphology to the secretion of known enzymatic markers for secondary metabolism, viz. succinate dehydrogenase and cytochrome C oxidoreductase. Detailed structure-function analysis of the biofilm using transmission electron microscopy and adapted enzyme cytochemical staining techniques showed that the biofilm appeared to operate as a co-ordinated unit, with primary and secondary metabolism apparently linked in one thallus through nutrient translocation. This study provided new insights into the physiology of P. chrysosp,o rium and a detailed descriptive model was formulated which correlates well to existing models of wood degradation by the white rot fungi (WRF). Evaluation of the process on a laboratory scale using a novel transverse flow membrane bioreactor showed that a volumetric productivity of 1916 U.L.⁻¹day⁻¹ for manganese peroxidase, one of the pollutant degrading enzymes, could be attained, corresponding to a final concentration of 2 361 U.L.⁻¹ This may be compared to the best reported system (Moreira el at. 1997), where a volumetric productivity of 202 U.L.⁻¹day⁻¹was achieved with a final concentration of 250 U.L.⁻¹ However, MGR productivity is yet to be subjected to rigorous optimisation studies. The process could be operated continuously for 60 days. However, peak productivity could not be maintained for long periods. This was found to be due to physical phenomena relating to the fluid dynamics of the system which caused fluid flow maldistribution, which would have to be resolved through engineering analysis. In evaluation of the MGR concept for aromatic pollutant removal, in this case ρ- cresol, from growth medium, good performance was also achieved. The VmaxKm calculated by linear regression for the MGR was 0.8 (R² = 0.93), which compared favourably to that reported by Lewandowski et al. (1990), who obtained a Vmax/Km of 0.34 for a packed bed reactor treating chlorophenol. It was concluded that the MGR showed suitable potential to warrant further development, and that the descriptive characterisation of the biofilm physiology provided a sufficient basis for process analysis once engineering aspects ofthe system could be resolved.
- Full Text:
- Authors: Leukes, Winston D
- Date: 1999
- Subjects: Aromatic compounds Pollutants Fungi Bioremediation Industrial microbiology Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4032 , http://hdl.handle.net/10962/d1004092
- Description: Bioremediation of aromatic pollutants using the ligninolytic enzymes of the white rot fungi has been thoroughly researched and has been shown to have considerable potential for industrial application. However, little success in scale-up and industrialisation of this technology has been attained due to problems associated with the continuous production of the pollutant-degrading enzymes using conventional bioreactor systems. The low productivities reported result from the incompatibility of conventional submerged culture reactor techniques with the physiological requirements of these fungi which have evolved on a solid-air interface, viz. wood. The enzymes are also produced only during the stationary phase of growth and can therefore be regarded as secondary metabolites. This study reports the conceptualisation, characterisation and evaluation of a novel bioreactor system as a solution to the continuous production of idiophasic pollutant degrading enzymes by the white rot fungus Phanerochaete chlysosporium. The reactor concept evolved from observation of these fungi in their native state, i. e. the metabolism of lignocellulosic material and involves the immobilisation of the organism onto a capillary ultrafiltration membrane. Nutrient gradients established across the biofilm, an inherent characteristic of fixed bed perfusion reactors, are exploited to provide both nutrient rich and nutrient poor zones across the biofilm. This allows growth or primary metabolism in the nutrient rich zone, pushing older biomass into the nutrient poor zone where secondary metabolism is induced by nutrient starvation. In effect, this represents a transformation of the events of a batch culture from a temporal to a spatial domain, allowing continuous production of secondary metabolites over time. Direct contact of the outer part of the biofilm with an air stream simulated the solid-air interface of the native state of the fungus. In order to facilitate the practical application of the membrane gradostat reactor (MGR) concept, conventional capillary membranes and membrane bioreactor modules were first evaluated. These were found to be unsuitable for application of the MGR concept. However, critical analysis of the shortcomings of the conventional systems resulted in the formulation of a set of design criteria for the development of a suitable membrane and module. These design criteria were satisfied by the development of a novel capillary membrane for membrane bioreactors, as well as a transverse flow membrane module, which is a novel approach in membrane bioreactor configuration. For the physiological characterisation of the MGR concept, a single fibre bioreactor unit was designed, which allowed destructive sampling of the biofilm for analysis. Using this system, it was shown that distinct morphological zones could be observed radially across the mature biofilm obtained through MGR operation. That these morphotypes do represent the temporal events of a typical batch culture in a spatial domain was confirmed by following the morphological changes occurring during batch culture of the immobilised fungus where the onset of primary and secondary metabolic conditions were manipulated through control of the nutrient supply. The different morphotypes were correlated to distinct growth phases by comparison of the morphology to the secretion of known enzymatic markers for secondary metabolism, viz. succinate dehydrogenase and cytochrome C oxidoreductase. Detailed structure-function analysis of the biofilm using transmission electron microscopy and adapted enzyme cytochemical staining techniques showed that the biofilm appeared to operate as a co-ordinated unit, with primary and secondary metabolism apparently linked in one thallus through nutrient translocation. This study provided new insights into the physiology of P. chrysosp,o rium and a detailed descriptive model was formulated which correlates well to existing models of wood degradation by the white rot fungi (WRF). Evaluation of the process on a laboratory scale using a novel transverse flow membrane bioreactor showed that a volumetric productivity of 1916 U.L.⁻¹day⁻¹ for manganese peroxidase, one of the pollutant degrading enzymes, could be attained, corresponding to a final concentration of 2 361 U.L.⁻¹ This may be compared to the best reported system (Moreira el at. 1997), where a volumetric productivity of 202 U.L.⁻¹day⁻¹was achieved with a final concentration of 250 U.L.⁻¹ However, MGR productivity is yet to be subjected to rigorous optimisation studies. The process could be operated continuously for 60 days. However, peak productivity could not be maintained for long periods. This was found to be due to physical phenomena relating to the fluid dynamics of the system which caused fluid flow maldistribution, which would have to be resolved through engineering analysis. In evaluation of the MGR concept for aromatic pollutant removal, in this case ρ- cresol, from growth medium, good performance was also achieved. The VmaxKm calculated by linear regression for the MGR was 0.8 (R² = 0.93), which compared favourably to that reported by Lewandowski et al. (1990), who obtained a Vmax/Km of 0.34 for a packed bed reactor treating chlorophenol. It was concluded that the MGR showed suitable potential to warrant further development, and that the descriptive characterisation of the biofilm physiology provided a sufficient basis for process analysis once engineering aspects ofthe system could be resolved.
- Full Text:
Development of integrated biological processing for the biodesalination of sulphate- and metal-rich wastewaters
- Authors: Boshoff, Genevieve Ann
- Date: 1999
- Subjects: Sewage -- Purification -- Biological treatment Sulfates Mineral industries -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3899 , http://hdl.handle.net/10962/d1003958
- Description: The substantial pollution threat to the South African environment from acid mine drainage (AMD) effluents has been well documented. Due to the juvenile nature of acidity in these flows, any remediation strategies implemented will need to function effectively and at low cost for long periods of time. The widespread use of sulphate reducing biological systems for the treatment of such effluents, and in particular large volume flows, has been limited. The supply of inexpensive electron donor and carbon sources, as well as appropriate reactor designs capable of handling large volume flows, have been identified as among the principal factors limiting development of this technology. The broad aim of the research programme reported here was to undertake an evaluation of the feasibility of an algal-bacterial integrated ponding system for the treatment of AMD, and the waste stabilisation pond (WSP) as an appropriate reactor design for this application. The study attempted to demonstrate the feasibility of individual unit operations in a proposed process train using complex organic carbon serving as the electron donor source for the sulphate reducing bacteria (SRB). Studies were undertaken as laboratory and pilot-scale investigations. Tannery effluent was shown to be a functional carbon source for biological sulphate reduction, with effective removal of sulphate and organics being recorded. In turn, the use of biological sulphate reduction for the treatment of tannery effluent was demonstrated. Algal biomass was shown in laboratory studies to function as an effective carbon source for biological sulphate reduction. It is known that micro-algae produce large quantities of photosynthate which is released to the growth medium under conditions of physiological stress. The potential for the use of photosynthate production in high rate algal ponding systems and its manipulation and use as a sustainable carbon source for sulphate reduction was investigated. Growth of a mixed culture of Dunaliella under conditions of light, temperature and salinity stress demonstrated production of large quantities of organic carbon. However, growth was inhibited at high temperatures. An elevation of salinity levels led to a decrease in growth of Dunaliella, but to increased organic carbon production. Spirulina spp., on the other hand, grew well at higher temperatures but showed the highest organic carbon production, and release to the medium, under low light conditions. These results led to a proposed process for the integration of algal ponding into an integrated system for the treatment of AMD. The algal biomass may be fed into the anaerobic digester as a carbon source, or it may be passed into a High Rate Algal Pond (HRAP) where it is stressed to enhance the organic carbon content. This can then be fed into the anaerobic digester as a carbon source. The impact of high levels of sulphide in the water feeding to the algal growth compartment was investigated. Spirulina spp. isolated from a tannery waste stabilisation pond was shown to be a sulphidophilic strain of cyanobacterium, capable of being adapted to high concentrations of sulphide. Dunaliella salina on the other hand was less tolerant. These results demonstrated the practical use of algal biomass providing an oxygen-rich cap for odour control on the surface of the facultative pond as well for the secondary treatment of sulphide-rich overflow to the High Rate Algal Pond. The ability of micro-algae to elevate the pH of their surrounding environment was evaluated as a functional precipitant and neutralisation reagent for acidic metal containing wastewater. Spirulina spp. was shown to perform effectively. D. salina was less functional in this environment. Anacystis spp. was effective in elevating the pH of a defined medium as well as a zinc-rich effluent. These results indicated the practicality of a neutralising function for algal ponds in the treatment of AMD. Metal removal in the system was found to be a combined function of sulphide precipitation, removal by binding to micro-algal biomass and extracellular polymeric substances. The feasibility of waste stabilisation ponding technology use for the treatment of large volume AMD effluents was provisionally demonstrated. It was shown that complex carbon sources would be used as efficient electron donors for sulphate reduction. The integration of algal ponding into the system provides for the generation of a sustainable carbon source, odour control with the recycling of oxygen-rich water onto the top of the facultative pond, secondary treatment of the anaerobic digester overflow, and the neutralisation of the incoming acidic effluents and removal of heavy metals. Integration of the individual unit operations, the feasibility of which has been provisionally demonstrated in this study, into a continuous process train is being investigated in follow-upstudies.
- Full Text:
- Authors: Boshoff, Genevieve Ann
- Date: 1999
- Subjects: Sewage -- Purification -- Biological treatment Sulfates Mineral industries -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3899 , http://hdl.handle.net/10962/d1003958
- Description: The substantial pollution threat to the South African environment from acid mine drainage (AMD) effluents has been well documented. Due to the juvenile nature of acidity in these flows, any remediation strategies implemented will need to function effectively and at low cost for long periods of time. The widespread use of sulphate reducing biological systems for the treatment of such effluents, and in particular large volume flows, has been limited. The supply of inexpensive electron donor and carbon sources, as well as appropriate reactor designs capable of handling large volume flows, have been identified as among the principal factors limiting development of this technology. The broad aim of the research programme reported here was to undertake an evaluation of the feasibility of an algal-bacterial integrated ponding system for the treatment of AMD, and the waste stabilisation pond (WSP) as an appropriate reactor design for this application. The study attempted to demonstrate the feasibility of individual unit operations in a proposed process train using complex organic carbon serving as the electron donor source for the sulphate reducing bacteria (SRB). Studies were undertaken as laboratory and pilot-scale investigations. Tannery effluent was shown to be a functional carbon source for biological sulphate reduction, with effective removal of sulphate and organics being recorded. In turn, the use of biological sulphate reduction for the treatment of tannery effluent was demonstrated. Algal biomass was shown in laboratory studies to function as an effective carbon source for biological sulphate reduction. It is known that micro-algae produce large quantities of photosynthate which is released to the growth medium under conditions of physiological stress. The potential for the use of photosynthate production in high rate algal ponding systems and its manipulation and use as a sustainable carbon source for sulphate reduction was investigated. Growth of a mixed culture of Dunaliella under conditions of light, temperature and salinity stress demonstrated production of large quantities of organic carbon. However, growth was inhibited at high temperatures. An elevation of salinity levels led to a decrease in growth of Dunaliella, but to increased organic carbon production. Spirulina spp., on the other hand, grew well at higher temperatures but showed the highest organic carbon production, and release to the medium, under low light conditions. These results led to a proposed process for the integration of algal ponding into an integrated system for the treatment of AMD. The algal biomass may be fed into the anaerobic digester as a carbon source, or it may be passed into a High Rate Algal Pond (HRAP) where it is stressed to enhance the organic carbon content. This can then be fed into the anaerobic digester as a carbon source. The impact of high levels of sulphide in the water feeding to the algal growth compartment was investigated. Spirulina spp. isolated from a tannery waste stabilisation pond was shown to be a sulphidophilic strain of cyanobacterium, capable of being adapted to high concentrations of sulphide. Dunaliella salina on the other hand was less tolerant. These results demonstrated the practical use of algal biomass providing an oxygen-rich cap for odour control on the surface of the facultative pond as well for the secondary treatment of sulphide-rich overflow to the High Rate Algal Pond. The ability of micro-algae to elevate the pH of their surrounding environment was evaluated as a functional precipitant and neutralisation reagent for acidic metal containing wastewater. Spirulina spp. was shown to perform effectively. D. salina was less functional in this environment. Anacystis spp. was effective in elevating the pH of a defined medium as well as a zinc-rich effluent. These results indicated the practicality of a neutralising function for algal ponds in the treatment of AMD. Metal removal in the system was found to be a combined function of sulphide precipitation, removal by binding to micro-algal biomass and extracellular polymeric substances. The feasibility of waste stabilisation ponding technology use for the treatment of large volume AMD effluents was provisionally demonstrated. It was shown that complex carbon sources would be used as efficient electron donors for sulphate reduction. The integration of algal ponding into the system provides for the generation of a sustainable carbon source, odour control with the recycling of oxygen-rich water onto the top of the facultative pond, secondary treatment of the anaerobic digester overflow, and the neutralisation of the incoming acidic effluents and removal of heavy metals. Integration of the individual unit operations, the feasibility of which has been provisionally demonstrated in this study, into a continuous process train is being investigated in follow-upstudies.
- Full Text:
Dramatic learning : a case study of theatre for development and environmental education
- Authors: Burt, Jane Caroline
- Date: 1999
- Subjects: Drama in education -- South Africa Environmental education -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1501 , http://hdl.handle.net/10962/d1003383
- Description: The aim of my research was to introduce drama, in the form of theatre for development processes, to local Grahamstown Primary School teachers, and to work closely with one teacher to explore theatre for development in the classroom, as a means of introducing both environmental education and learner-centred, constructivist teaching methodologies. I started my research by interviewing Primary School principals as well as sending out questionnaires to teachers, to survey their understanding and practice of drama and environmental education in the school curriculum and to invite them to participate in the research project. In collaboration with Educational Drama and Theatre students, I developed two workshops to introduce theatre for development processes such as image theatre and role-play to the teachers. Nine teachers attended this workshop which was video-taped. After the workshop I gave two lessons at a local school, in partnership with a teacher. Throughout this process I kept a research journal. All action components of the research were followed up with individual interviews, group discussions and a focus group. Although the study gave rise to multiple themes, I chose to highlight two: Firstly, Curriculum 2005 advocates a move towards more learner-centred,constructivist and process-orientated pedagogies. All of the participants in this study, including myself, had intentions of adopting a new approach tq education and teaching but found that we often reverted back to earlier learnt roles of product-orientated, text-based, authoritarian approaches to education which we originally had rejected. Secondly, I reflect on how we set out viewing environmental education, education, drama and research as a process and yet all the participants, including myself, continually tried to 'put on' the perfect performance in the form of a drama, a learning experience and research. This project was a participatory research project. The textwork of the research reflects a post-structural orientation. It has been written in the form of a drama to represent the many voices of the participants, but also to question the role of research in society and make research more accessible to non-academic readers. I also intend to perform the research process at a later stage.
- Full Text:
- Authors: Burt, Jane Caroline
- Date: 1999
- Subjects: Drama in education -- South Africa Environmental education -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1501 , http://hdl.handle.net/10962/d1003383
- Description: The aim of my research was to introduce drama, in the form of theatre for development processes, to local Grahamstown Primary School teachers, and to work closely with one teacher to explore theatre for development in the classroom, as a means of introducing both environmental education and learner-centred, constructivist teaching methodologies. I started my research by interviewing Primary School principals as well as sending out questionnaires to teachers, to survey their understanding and practice of drama and environmental education in the school curriculum and to invite them to participate in the research project. In collaboration with Educational Drama and Theatre students, I developed two workshops to introduce theatre for development processes such as image theatre and role-play to the teachers. Nine teachers attended this workshop which was video-taped. After the workshop I gave two lessons at a local school, in partnership with a teacher. Throughout this process I kept a research journal. All action components of the research were followed up with individual interviews, group discussions and a focus group. Although the study gave rise to multiple themes, I chose to highlight two: Firstly, Curriculum 2005 advocates a move towards more learner-centred,constructivist and process-orientated pedagogies. All of the participants in this study, including myself, had intentions of adopting a new approach tq education and teaching but found that we often reverted back to earlier learnt roles of product-orientated, text-based, authoritarian approaches to education which we originally had rejected. Secondly, I reflect on how we set out viewing environmental education, education, drama and research as a process and yet all the participants, including myself, continually tried to 'put on' the perfect performance in the form of a drama, a learning experience and research. This project was a participatory research project. The textwork of the research reflects a post-structural orientation. It has been written in the form of a drama to represent the many voices of the participants, but also to question the role of research in society and make research more accessible to non-academic readers. I also intend to perform the research process at a later stage.
- Full Text:
Dreamwork and imaginal healing: the incorporation of artwork in a systematized method of group dreamwork
- Authors: Euvrard, Gwenda Joan
- Date: 1999
- Subjects: Dreams -- Therapeutic use , Art therapy , Jungian psychology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2972 , http://hdl.handle.net/10962/d1002481 , Dreams -- Therapeutic use , Art therapy , Jungian psychology
- Description: This exploratory study investigated the expansion of an established systematized group dreamwork method (Shuttleworth-Jordan, 1995) to incorporate artwork. The rationale for the addition of artwork was situated firstly, in a poetic Jungian understanding of the image as a holistic "place" of gnosis or transformative healing and, secondly, in an argument that in order to carry the gnostic potential of the image into the lived world, a dreamwork method should involve all four styles of consciousness (thinking, intuition, sensation and feeling). It was considered that the verbal interpretive Shuttleworth-Jordan method would be enhanced by the incorporation of a visual artwork process in order more fully to open the potential of the method for incorporating the nonverbal intuitive, sensation and feeling styles of consciousness. In order to compare the established method (dreamwork Without Art) and the proposed method (dreamwork With Art), two dreamwork workshops were conducted in which all participants experienced all four conditions of the study: Dream Presenter Without Art, Dream Presenter With Art, Group Member Without Art, Group Member With Art. Two levels of assessment were utilized: a quantitative analysis (involving rating scales completed after each dreamwork session), supported by a qualitative analysis (involving written questionnaires completed at the end of the workshops and follow-up interviews conducted a week after completion of the workshops). The results suggested that the incorporation of artwork in the Shuttleworth-Jordan (1995) group dreamwork method enhanced the established method in that a consistent trend of increased involvement in the dreamwork process and increased dreamwork effectiveness was reflected, while no deleterious effects were noted which might detract from the effectiveness of the existing model which had been established in previous research studies. Finally, a refined step-by-step group dreamwork method incorporating artwork was proposed, which included qualitative feedback from the present study.
- Full Text:
- Authors: Euvrard, Gwenda Joan
- Date: 1999
- Subjects: Dreams -- Therapeutic use , Art therapy , Jungian psychology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2972 , http://hdl.handle.net/10962/d1002481 , Dreams -- Therapeutic use , Art therapy , Jungian psychology
- Description: This exploratory study investigated the expansion of an established systematized group dreamwork method (Shuttleworth-Jordan, 1995) to incorporate artwork. The rationale for the addition of artwork was situated firstly, in a poetic Jungian understanding of the image as a holistic "place" of gnosis or transformative healing and, secondly, in an argument that in order to carry the gnostic potential of the image into the lived world, a dreamwork method should involve all four styles of consciousness (thinking, intuition, sensation and feeling). It was considered that the verbal interpretive Shuttleworth-Jordan method would be enhanced by the incorporation of a visual artwork process in order more fully to open the potential of the method for incorporating the nonverbal intuitive, sensation and feeling styles of consciousness. In order to compare the established method (dreamwork Without Art) and the proposed method (dreamwork With Art), two dreamwork workshops were conducted in which all participants experienced all four conditions of the study: Dream Presenter Without Art, Dream Presenter With Art, Group Member Without Art, Group Member With Art. Two levels of assessment were utilized: a quantitative analysis (involving rating scales completed after each dreamwork session), supported by a qualitative analysis (involving written questionnaires completed at the end of the workshops and follow-up interviews conducted a week after completion of the workshops). The results suggested that the incorporation of artwork in the Shuttleworth-Jordan (1995) group dreamwork method enhanced the established method in that a consistent trend of increased involvement in the dreamwork process and increased dreamwork effectiveness was reflected, while no deleterious effects were noted which might detract from the effectiveness of the existing model which had been established in previous research studies. Finally, a refined step-by-step group dreamwork method incorporating artwork was proposed, which included qualitative feedback from the present study.
- Full Text:
Drie susters II
- Authors: De Wet, Reza
- Date: 1999
- Subjects: To be catalogued
- Language: Afrikaans
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469612 , vital:77272
- Description: Masja (laggie): O, ek weet wat jy dink... Jy dink dis Marofski... Dat hy my ongelukkig maak. Ja, ek weet hy het 'n reputasie. So 'n paar weke na ek saam met hom weg is... alles vir hom opgeoffer het... het hy een nag nooit huis toe gekom nie, en toe ek die volgende oggend vra waar hy was... (Laggie) het hy gesê: "My liefling, jy dink tog nie jy is genoeg vir my nie." Ek het gevoel asof ek sou sterf. Ek wou weggaan... Dadelik weggaan... Maar ek kon nie! As hy net na my kyk... aan my raak... Ek was heeltemal verlore... Asof ek deur 'n diep, donkerstroom meegesleur word en niks daaraan kon doen nie. Vir jare het dit so aangegaan. En toe... het iets gebeur. Dit was sommer 'n kleinigheidjie. (Bars uit van die lag. Sukkel om tussen die lag deur te praai) Een nag... het hy weer laat by die huis gekom... en sommer in sy klere aan die slaap geraag. Net sy skoene uitgeskop. En toe sien ek skielik... hoe klein sy voete is. So klein soos 'n vroe se voete. Hy het gestreepte sokkies aangehad, en aan die punt van elkeen, het... 'n... stukkie wit... garing... in die lug opgestaan. (Wys met haar twee wysvingers, hyg na asem en vee haar oë af) Snaaks... maar daarna het ek sterker geword en hy... Dit was asof hy skielik bang was om my te verloor. (Staan op en loop na die venster) Maar dis nie Marofski nie... Arme Marofski... Dis veel erger as dit. (Draai om en kyk na hom) Dit raak nie net vir my nie... maar vir ons almal.
- Full Text:
- Authors: De Wet, Reza
- Date: 1999
- Subjects: To be catalogued
- Language: Afrikaans
- Type: text , article
- Identifier: http://hdl.handle.net/10962/469612 , vital:77272
- Description: Masja (laggie): O, ek weet wat jy dink... Jy dink dis Marofski... Dat hy my ongelukkig maak. Ja, ek weet hy het 'n reputasie. So 'n paar weke na ek saam met hom weg is... alles vir hom opgeoffer het... het hy een nag nooit huis toe gekom nie, en toe ek die volgende oggend vra waar hy was... (Laggie) het hy gesê: "My liefling, jy dink tog nie jy is genoeg vir my nie." Ek het gevoel asof ek sou sterf. Ek wou weggaan... Dadelik weggaan... Maar ek kon nie! As hy net na my kyk... aan my raak... Ek was heeltemal verlore... Asof ek deur 'n diep, donkerstroom meegesleur word en niks daaraan kon doen nie. Vir jare het dit so aangegaan. En toe... het iets gebeur. Dit was sommer 'n kleinigheidjie. (Bars uit van die lag. Sukkel om tussen die lag deur te praai) Een nag... het hy weer laat by die huis gekom... en sommer in sy klere aan die slaap geraag. Net sy skoene uitgeskop. En toe sien ek skielik... hoe klein sy voete is. So klein soos 'n vroe se voete. Hy het gestreepte sokkies aangehad, en aan die punt van elkeen, het... 'n... stukkie wit... garing... in die lug opgestaan. (Wys met haar twee wysvingers, hyg na asem en vee haar oë af) Snaaks... maar daarna het ek sterker geword en hy... Dit was asof hy skielik bang was om my te verloor. (Staan op en loop na die venster) Maar dis nie Marofski nie... Arme Marofski... Dis veel erger as dit. (Draai om en kyk na hom) Dit raak nie net vir my nie... maar vir ons almal.
- Full Text:
DSC screening of potential prochlorperazine-excipient interactions in preformulation studies
- Brown, Michael E, Antunes, Edith M, Glass, Beverley M, Lebete, Mosimotsana L, Walker, Roderick B
- Authors: Brown, Michael E , Antunes, Edith M , Glass, Beverley M , Lebete, Mosimotsana L , Walker, Roderick B
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184367 , vital:44212 , xlink:href="https://doi.org/10.1023/A:1010150305542"
- Description: Differential scanning calorimetry was used to examine the thermal behaviour of mixtures of the drug prochlorperazine with standard excipients, to assess potential interactions, and of mixtures with cyclodextrins, to investigate inclusion complexation which could increase the photostability of the drug. For most of the excipients (magnesium stearate, stearic acid, Explotab®, Ac-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab® was the only 'inert' excipient tested. Mixtures of prochlorperazine and the cyclodextrins gave incomplete inclusion complexation as shown by only partial disappearance of the melting endotherm of the drug.
- Full Text: false
- Authors: Brown, Michael E , Antunes, Edith M , Glass, Beverley M , Lebete, Mosimotsana L , Walker, Roderick B
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184367 , vital:44212 , xlink:href="https://doi.org/10.1023/A:1010150305542"
- Description: Differential scanning calorimetry was used to examine the thermal behaviour of mixtures of the drug prochlorperazine with standard excipients, to assess potential interactions, and of mixtures with cyclodextrins, to investigate inclusion complexation which could increase the photostability of the drug. For most of the excipients (magnesium stearate, stearic acid, Explotab®, Ac-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab® was the only 'inert' excipient tested. Mixtures of prochlorperazine and the cyclodextrins gave incomplete inclusion complexation as shown by only partial disappearance of the melting endotherm of the drug.
- Full Text: false
Effect of concentration and degree of saturation of topical fluocinonide formulations on in vitro membrane transport and in vivo availability on human skin
- Schwarb, Fabian P, Imanidis, Georgios, Smith, Eric W, Haigh, John M, Surber, Christian
- Authors: Schwarb, Fabian P , Imanidis, Georgios , Smith, Eric W , Haigh, John M , Surber, Christian
- Date: 1999
- Language: English
- Type: text , Article
- Identifier: vital:6425 , http://hdl.handle.net/10962/d1006560
- Description: Purpose. The thermodynamic acitvity of drugs in topical vehicles is considered to significantly influence topical delivery. In vitro diffusion across a synthetic membrane was shown to be correlated to the degree of saturation of the drug in the applied vehicle and therefore offers a potential for increased topical drug delivery. Fluocinonide a topical corticosteroid, was chosen as a model compound to investigate in vitro and in vivo availability from formulations with different degrees of saturation. Methods. Sub-, as well as, supersaturated drug solutions were prepared using PVP as an antinucleant agent. In vitro membrane diffusion experiments across silicone membrane and in vivo pharmacodynamic activity assessments, using the human skin blanching assay, were carried out. Results. Over the concentration range studied, the in vitro membrane transport of fluocinonide was proportional to the degree of saturation of the respective formulations. The in vivo pharmacodynamic response in the human skin blanching assay was related to the concentration of the drug in the vehicle irrespective of the degree of saturation. Conclusions. From the membrane permeation experiment it can be concluded, that the drug flux might be increased supra-proportionally with increasing donor concentration, drug (super-)saturation (proportional), beyond what would be anticipated based on ideal donor concentration and partition coefficient considerations only. These findings could not be confirmed in the in vivo investigation, probably due to additional vehicle effects (e.g., enhancement, irritation, drug binding) which have to be expected and could have altered the integrity of the stratum corneum and therewith topical bioavailability of the drug.
- Full Text: false
- Authors: Schwarb, Fabian P , Imanidis, Georgios , Smith, Eric W , Haigh, John M , Surber, Christian
- Date: 1999
- Language: English
- Type: text , Article
- Identifier: vital:6425 , http://hdl.handle.net/10962/d1006560
- Description: Purpose. The thermodynamic acitvity of drugs in topical vehicles is considered to significantly influence topical delivery. In vitro diffusion across a synthetic membrane was shown to be correlated to the degree of saturation of the drug in the applied vehicle and therefore offers a potential for increased topical drug delivery. Fluocinonide a topical corticosteroid, was chosen as a model compound to investigate in vitro and in vivo availability from formulations with different degrees of saturation. Methods. Sub-, as well as, supersaturated drug solutions were prepared using PVP as an antinucleant agent. In vitro membrane diffusion experiments across silicone membrane and in vivo pharmacodynamic activity assessments, using the human skin blanching assay, were carried out. Results. Over the concentration range studied, the in vitro membrane transport of fluocinonide was proportional to the degree of saturation of the respective formulations. The in vivo pharmacodynamic response in the human skin blanching assay was related to the concentration of the drug in the vehicle irrespective of the degree of saturation. Conclusions. From the membrane permeation experiment it can be concluded, that the drug flux might be increased supra-proportionally with increasing donor concentration, drug (super-)saturation (proportional), beyond what would be anticipated based on ideal donor concentration and partition coefficient considerations only. These findings could not be confirmed in the in vivo investigation, probably due to additional vehicle effects (e.g., enhancement, irritation, drug binding) which have to be expected and could have altered the integrity of the stratum corneum and therewith topical bioavailability of the drug.
- Full Text: false
Effects of zone and wave exposure on population structure and recruitment of the mussel (Perna perna) in South Africa
- Authors: Lindsay, Justin Robert
- Date: 1999
- Subjects: Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5685 , http://hdl.handle.net/10962/d1005371 , Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Description:
Certain aspects of the population dynamics of the brown mussel, Perna perna, were examined at 18 sites along the south coast of South African. Specifically the effects of wave exposure and tidal height were examined in relation to mussel size, biomass and density. A single set of samples was removed from each of the 18 sites, over three spring tide cycles. Sites were classified as exposed or sheltered prior to sampling. Principal component analysis (PCA) (based on mussel length data) and length frequency histograms revealed that there was a general decrease in the modal size of the adult mussel cohort with an increase in tidal height. The effects of exposure on mussel size decreased higher on the shore. On the exposed low shore the maximum size of mussels had a mean length of 102.3mm and was significantly larger (ANOVA, p<0.0001) than that for mussels on sheltered shores (86.7mm). The difference between mean maximum lengths of mussels on the mid shore was not so great, exposed sites had a average mean maximum length of 79.9, while on the sheltered shores it was 68.4mm. On the high shore the difference between the average mean maximum lengths at exposed and sheltered sites was only 3.9mm. The fact that the effects of exposure were greatest on the low shore was also borne out in the PCA. In this analysis low shore exposed and sheltered zones separated into two groups with little overlap, mid shore exposed and sheltered zones were positioned next to each other, and exposed and sheltered high shore zones were clumped together. Densities of adult mussels (>l5mm) were calculated as real densities from randomly placed quads i.e. not from areas of 100% cover. Density decreased up the shore; low, mid and high shore zones were significantly different from each other (ANOVA , p<0.0001; followed by multiple range tests). There was no significant difference between the densities of mussels at exposed and sheltered sites within each zone (ANOVA, p=0.7155). Recruit (
- Full Text:
- Authors: Lindsay, Justin Robert
- Date: 1999
- Subjects: Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5685 , http://hdl.handle.net/10962/d1005371 , Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Description:
Certain aspects of the population dynamics of the brown mussel, Perna perna, were examined at 18 sites along the south coast of South African. Specifically the effects of wave exposure and tidal height were examined in relation to mussel size, biomass and density. A single set of samples was removed from each of the 18 sites, over three spring tide cycles. Sites were classified as exposed or sheltered prior to sampling. Principal component analysis (PCA) (based on mussel length data) and length frequency histograms revealed that there was a general decrease in the modal size of the adult mussel cohort with an increase in tidal height. The effects of exposure on mussel size decreased higher on the shore. On the exposed low shore the maximum size of mussels had a mean length of 102.3mm and was significantly larger (ANOVA, p<0.0001) than that for mussels on sheltered shores (86.7mm). The difference between mean maximum lengths of mussels on the mid shore was not so great, exposed sites had a average mean maximum length of 79.9, while on the sheltered shores it was 68.4mm. On the high shore the difference between the average mean maximum lengths at exposed and sheltered sites was only 3.9mm. The fact that the effects of exposure were greatest on the low shore was also borne out in the PCA. In this analysis low shore exposed and sheltered zones separated into two groups with little overlap, mid shore exposed and sheltered zones were positioned next to each other, and exposed and sheltered high shore zones were clumped together. Densities of adult mussels (>l5mm) were calculated as real densities from randomly placed quads i.e. not from areas of 100% cover. Density decreased up the shore; low, mid and high shore zones were significantly different from each other (ANOVA , p<0.0001; followed by multiple range tests). There was no significant difference between the densities of mussels at exposed and sheltered sites within each zone (ANOVA, p=0.7155). Recruit (
- Full Text:
Electrochemical studies of gold bioaccumulation by yeast cell wall components
- Authors: Lack, Barbara Anne
- Date: 1999
- Subjects: Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4311 , http://hdl.handle.net/10962/d1004969 , Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Description: Gold, amongst other group 11 metals, was almost certainly one of the first three metals known to man. In addition to the economic importance of the metal, gold has a wide variety of applications in the medical, electrocatalytical and micro-electronics fields. However, the determination of gold ions in solution, with accuracy, precision, sensitivity and selectivity is still an interesting and much debated topic in analytical chemistry. A system whereby gold ions have been successfully detected employing an electrochemical technique, known as stripping voltammetry, has been developed. The electrochemical method was chosen over other available techniques for the sensitivity, particularly at low concentrations, and selectivity properties; notably in the presence of other metal ions. Under acidic conditions, the electrochemical technique was applied and the presence of gold(III), at a concentration of 2.53 x 10⁻⁵ mol dm⁻³ in a mine waste water sample, was detected. Biomass, in particular yeast and algal types, have been successfully employed in extracting low concentrations of gold ions from industrial effluents. The manipulation of the biological facility for mineral interaction, biohydrometallurgy, may yield numerous potential new technologies. South Africa in particular would benefit from this area of research, since the country is a major ore and metal refining country and if the output and the efficiency of the mines could be improved, even by a small percentage, the financial rewards would be vast. In this study, the application of adsorptive cathodic stripping voltammetry (AdCSV) of gold(III) in the presence of various Saccharomyces cerevisiae cell wall components, was investigated to determine which, if any, were involved specifically in the chemical binding of the gold ions. The chitin and mannan extracts showed the most promise with detection limits of 1.10 x 10⁻⁶ mol dm⁻³ and 9 x 10⁻⁹ mol dm⁻³, respectively; employing the AdCSV technique. A modification of the stripping voltammetry technique, Osteryoung square wave stripping voltammetry (OSWSV), provided the lowest detection limit, for gold(IIl) in the presence of mannan, of 1.70 x 10⁻¹¹ mol dm⁻³ ; utilising a modified carbon paste electrode. The detection of gold(III) has been shown to be dependent on the type of electrode employed, the electrolyte solution and the presence of interfering agents. The effect of copper(II) and silver(I) on the detection of the gold(III) in solution was investigated; whilst the silver(I) has shown no detrimental effects on gold (III) detection systems, copper(II) has indicated the possibility of forming an inter-metallic compound with the gold(III). However, mannan has shown to selectively and preferentially bind the gold(III) in the presence of a ten-fold excess of copper(II). Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, as well as computer modelling techniques were employed to further investIgate the mannan-gold(III) interaction and proposed complex formed. The NMR, IR and computer modelling data are in agreement with the electrochemical data on proposing a mannan-gold(III) complex. The co-ordination site was established to be in the vicinity of the H-I and H-2 protons and the gold(III) adopts a square-planar geometry upon co-ordination. The benefits of the research are useful from a biological perspective (i. e. as more is known about the binding sites, microbiologists/biochemists may work on the optimisation of parameters for these sites or work could be furthered into the enhanced expression of the sites) and an industrial one. In addition to the' two major benefits, an improved understanding of gold and its chemistry would be achieved, which is advantageous for other fields of research as well.
- Full Text:
- Authors: Lack, Barbara Anne
- Date: 1999
- Subjects: Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4311 , http://hdl.handle.net/10962/d1004969 , Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Description: Gold, amongst other group 11 metals, was almost certainly one of the first three metals known to man. In addition to the economic importance of the metal, gold has a wide variety of applications in the medical, electrocatalytical and micro-electronics fields. However, the determination of gold ions in solution, with accuracy, precision, sensitivity and selectivity is still an interesting and much debated topic in analytical chemistry. A system whereby gold ions have been successfully detected employing an electrochemical technique, known as stripping voltammetry, has been developed. The electrochemical method was chosen over other available techniques for the sensitivity, particularly at low concentrations, and selectivity properties; notably in the presence of other metal ions. Under acidic conditions, the electrochemical technique was applied and the presence of gold(III), at a concentration of 2.53 x 10⁻⁵ mol dm⁻³ in a mine waste water sample, was detected. Biomass, in particular yeast and algal types, have been successfully employed in extracting low concentrations of gold ions from industrial effluents. The manipulation of the biological facility for mineral interaction, biohydrometallurgy, may yield numerous potential new technologies. South Africa in particular would benefit from this area of research, since the country is a major ore and metal refining country and if the output and the efficiency of the mines could be improved, even by a small percentage, the financial rewards would be vast. In this study, the application of adsorptive cathodic stripping voltammetry (AdCSV) of gold(III) in the presence of various Saccharomyces cerevisiae cell wall components, was investigated to determine which, if any, were involved specifically in the chemical binding of the gold ions. The chitin and mannan extracts showed the most promise with detection limits of 1.10 x 10⁻⁶ mol dm⁻³ and 9 x 10⁻⁹ mol dm⁻³, respectively; employing the AdCSV technique. A modification of the stripping voltammetry technique, Osteryoung square wave stripping voltammetry (OSWSV), provided the lowest detection limit, for gold(IIl) in the presence of mannan, of 1.70 x 10⁻¹¹ mol dm⁻³ ; utilising a modified carbon paste electrode. The detection of gold(III) has been shown to be dependent on the type of electrode employed, the electrolyte solution and the presence of interfering agents. The effect of copper(II) and silver(I) on the detection of the gold(III) in solution was investigated; whilst the silver(I) has shown no detrimental effects on gold (III) detection systems, copper(II) has indicated the possibility of forming an inter-metallic compound with the gold(III). However, mannan has shown to selectively and preferentially bind the gold(III) in the presence of a ten-fold excess of copper(II). Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, as well as computer modelling techniques were employed to further investIgate the mannan-gold(III) interaction and proposed complex formed. The NMR, IR and computer modelling data are in agreement with the electrochemical data on proposing a mannan-gold(III) complex. The co-ordination site was established to be in the vicinity of the H-I and H-2 protons and the gold(III) adopts a square-planar geometry upon co-ordination. The benefits of the research are useful from a biological perspective (i. e. as more is known about the binding sites, microbiologists/biochemists may work on the optimisation of parameters for these sites or work could be furthered into the enhanced expression of the sites) and an industrial one. In addition to the' two major benefits, an improved understanding of gold and its chemistry would be achieved, which is advantageous for other fields of research as well.
- Full Text:
Electrochemical studies of metal-ligand interactions and of metal binding proteins
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
Employment Equity: An Introductory Workshop for Trade Unionists Organised by the COSATU Education Department
- COSATU
- Authors: COSATU
- Date: 1999
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/176014 , vital:42652
- Description: This workshop is designed to give you a reliable introduction the Employment Equity Act. It is based on hard information and on ACTIVITIES or discussion exercises that will help you to understand how the Act works, who it covers, and what the implications are for trade unionists. Each of the Activities is complemented with information that will help you to understand the Act in more detail. Sections have been added to help you find further information, and to understand the terms that are used in the Act itself In a two day programme, you are not going to be an 'expert' on the Employment Equity Act, but we hope that you will feel more confident about using the Act, especially in ensuring that it is used to address a wide range of discriminatory practices at the workplace. As with most legislation, the more that you begin to use it, the more its strengths and weaknesses will emerge. It is very important that any weaknesses in the practical application of the Act are reported through your Union to the Federation. This will help the Federation to campaign for improvements in the legislation, and to close any loopholes that allow employers to avoid their responsibilities. All Labour Legislation, including the new Employment Equity Act should serve as a 'base-line' or minimum standard. Employer and Union observance of the minimum standards as laid down in law should be our starting point. Through collective bargaining and improved Union organisation, we aim to improve upon the standards set by the law, and increase the protection of our members. This is a real challenge. It is especially important for us all to recognise that as we enter into a period where employers are demanding more 'flexibility', the introduction of a new law to correct the legacy of imbalances left by apartheid at the workplace deserves our special attention. We hope this workshop is the first in a series of educational events that will cover this vital new area. The main aim of this workshop is to help you to understand the basic workings of the law, and how best it can be implemented. We also hope this programme encourages you to find out more about Employment Equity issues, and contribute positively to the struggle for the eradication of inequality. This pack is designed for a series of two-day introductory workshops that are being sponsored by COSATU in each region. A workshop of COSATU Educators held in September 1999 helped to assemble the material, and to test its appropriateness. As a result there are a considerable number of educators who can advise, and facilitate this workshop and who can be contacted via COSATU Education Department. We would also be very interested to hear how the pack has been used, and in particular how it can be improved to meet the needs of trade unionists who want to tackle discrimination using the tool of the Employment Equity Act, as well as other organisational means. If you use this pack, feedback would be most welcome.
- Full Text:
- Authors: COSATU
- Date: 1999
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/176014 , vital:42652
- Description: This workshop is designed to give you a reliable introduction the Employment Equity Act. It is based on hard information and on ACTIVITIES or discussion exercises that will help you to understand how the Act works, who it covers, and what the implications are for trade unionists. Each of the Activities is complemented with information that will help you to understand the Act in more detail. Sections have been added to help you find further information, and to understand the terms that are used in the Act itself In a two day programme, you are not going to be an 'expert' on the Employment Equity Act, but we hope that you will feel more confident about using the Act, especially in ensuring that it is used to address a wide range of discriminatory practices at the workplace. As with most legislation, the more that you begin to use it, the more its strengths and weaknesses will emerge. It is very important that any weaknesses in the practical application of the Act are reported through your Union to the Federation. This will help the Federation to campaign for improvements in the legislation, and to close any loopholes that allow employers to avoid their responsibilities. All Labour Legislation, including the new Employment Equity Act should serve as a 'base-line' or minimum standard. Employer and Union observance of the minimum standards as laid down in law should be our starting point. Through collective bargaining and improved Union organisation, we aim to improve upon the standards set by the law, and increase the protection of our members. This is a real challenge. It is especially important for us all to recognise that as we enter into a period where employers are demanding more 'flexibility', the introduction of a new law to correct the legacy of imbalances left by apartheid at the workplace deserves our special attention. We hope this workshop is the first in a series of educational events that will cover this vital new area. The main aim of this workshop is to help you to understand the basic workings of the law, and how best it can be implemented. We also hope this programme encourages you to find out more about Employment Equity issues, and contribute positively to the struggle for the eradication of inequality. This pack is designed for a series of two-day introductory workshops that are being sponsored by COSATU in each region. A workshop of COSATU Educators held in September 1999 helped to assemble the material, and to test its appropriateness. As a result there are a considerable number of educators who can advise, and facilitate this workshop and who can be contacted via COSATU Education Department. We would also be very interested to hear how the pack has been used, and in particular how it can be improved to meet the needs of trade unionists who want to tackle discrimination using the tool of the Employment Equity Act, as well as other organisational means. If you use this pack, feedback would be most welcome.
- Full Text:
Evaluation of a 'defouling on demand' strategy for the ultrafiltration of brown water using activatable enzymes
- Authors: Buchanan, K
- Date: 1999
- Subjects: Water -- Purification , Ultrafiltration , Enzymes , Membranes (Technology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3904 , http://hdl.handle.net/10962/d1003963 , Water -- Purification , Ultrafiltration , Enzymes , Membranes (Technology)
- Description: New approaches to the application of membranes for the production of potable water are constantly being sought after in anticipation of future demands for increasingly rigorous water quality standards and reduced environmental impact. A major limitation, however, is membrane fouling, which manifests itself as a continual reduction in flux over time and thus restricts the practical implementation to restore flux. Mechanical and chemical methods have been implemented to restore flux to ultrafiltration systems, but these either result in a break in the process operation or lead to membrane damage or additional pollution problems. This project was aimed to develop a 'defouling on demand' stategy for cleaning membranes used during brown water ultrafiltration. The process involves the use of activatable peroxidase enzymes, which were immobilised onto flat sheet polysulphone membranes. Following flux decline which reaches a critical level with the build-up of the foulant layer, the immobilised enzyme layer was activated by the addition of a chemical activator solution, in this case hydrogen peroxidase and manganous sulphate. Manganese peroxidase was found to be the most effective enzyme at alleviating fouling by degrading the foulant layer formed on the membrane surface and hence restored flux to the ultrafiltration system. A 93% flux improvement was observed when manganese peroxidase was activated when 800uM manganous sulphate, 100mM hydrogen peroxide were added in the presence of a manganese chelator, lactate. The concept and the potential benefits this system holds will be discussed in further detail.
- Full Text:
- Authors: Buchanan, K
- Date: 1999
- Subjects: Water -- Purification , Ultrafiltration , Enzymes , Membranes (Technology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3904 , http://hdl.handle.net/10962/d1003963 , Water -- Purification , Ultrafiltration , Enzymes , Membranes (Technology)
- Description: New approaches to the application of membranes for the production of potable water are constantly being sought after in anticipation of future demands for increasingly rigorous water quality standards and reduced environmental impact. A major limitation, however, is membrane fouling, which manifests itself as a continual reduction in flux over time and thus restricts the practical implementation to restore flux. Mechanical and chemical methods have been implemented to restore flux to ultrafiltration systems, but these either result in a break in the process operation or lead to membrane damage or additional pollution problems. This project was aimed to develop a 'defouling on demand' stategy for cleaning membranes used during brown water ultrafiltration. The process involves the use of activatable peroxidase enzymes, which were immobilised onto flat sheet polysulphone membranes. Following flux decline which reaches a critical level with the build-up of the foulant layer, the immobilised enzyme layer was activated by the addition of a chemical activator solution, in this case hydrogen peroxidase and manganous sulphate. Manganese peroxidase was found to be the most effective enzyme at alleviating fouling by degrading the foulant layer formed on the membrane surface and hence restored flux to the ultrafiltration system. A 93% flux improvement was observed when manganese peroxidase was activated when 800uM manganous sulphate, 100mM hydrogen peroxide were added in the presence of a manganese chelator, lactate. The concept and the potential benefits this system holds will be discussed in further detail.
- Full Text:
Experiencing space and place in Grahamstown's informal settlements
- Coetzee, Jan K, Houssay-Holzschuch, Myriam, O'Reilly, Caroline
- Authors: Coetzee, Jan K , Houssay-Holzschuch, Myriam , O'Reilly, Caroline
- Date: 1999
- Subjects: Black people -- housing -- South Africa -- South Africa -- Grahamstown Squatter settlements -- South Africa -- Grahamstown Squatters -- South Africa -- Grahamstown -- interviews
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/2623 , vital:20310 , ISBN 0868103616
- Description: In this research the relationship between people and the space they occupy will be looked at. In doing so, we shall see how people enter into a relationship with their environment in order to create out of material at their disposal, a shelter wherein they can live. By erecting a structure which serves as a house, the people involved in this project do essentially the same as other people in other parts of the world, who create a dwelling that provides protection against the climate and the elements in nature. A question to be raised, is extent their (i.e. the people involved in this project) entering into a relationship with their environment, was forced into a particular direction because of a set of political and economic factors. What are the political and economic factors which impact on the manner of building houses in the informal residential areas of Grahamstown? Traditional housing in France, for example, differs from region to region and has been shaped over long periods of time by the climate, family structures, the availability of land, modes of production, etc. One finds that large vine-growing families from the Mediterranean South of France live in fairly big villages; individual farmers of Brittany dwell in small, slate-roofed houses which are isolated among enclosed fields; pastoral communities in the Alps undertake seasonal moves up or down the slopes of the mountains and share their space during winter with their cattle. The way in which these families and/or communities have come to shape their lifeworlds, was not exposed to the same kind of determining factors as, for instance, in South Africa in general and in Grahamstown in particular. Notwithstanding political and economic determinants, it is clear that residents of informal houses in the Grahamstown area draw to a large extent from tradition with regards to the kind of shelters which they build (cf. the many mud-and-stick constructions). Similarly the settlement of people impacts on nature. Elements of the environment inform certain choices, but people interpret their natural environment and will erect shelters in terms of these interpretations. In addition there are the issues of how people orientate themselves in terms of important landmarks, what kind of representation they have of the future they are moving towards and which values do they draw from or attribute to their physical environment. The landscape surrounding people, contains and reflects cultural information. Important landmarks express aspects of life: the past, the present and the future. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Authors: Coetzee, Jan K , Houssay-Holzschuch, Myriam , O'Reilly, Caroline
- Date: 1999
- Subjects: Black people -- housing -- South Africa -- South Africa -- Grahamstown Squatter settlements -- South Africa -- Grahamstown Squatters -- South Africa -- Grahamstown -- interviews
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/2623 , vital:20310 , ISBN 0868103616
- Description: In this research the relationship between people and the space they occupy will be looked at. In doing so, we shall see how people enter into a relationship with their environment in order to create out of material at their disposal, a shelter wherein they can live. By erecting a structure which serves as a house, the people involved in this project do essentially the same as other people in other parts of the world, who create a dwelling that provides protection against the climate and the elements in nature. A question to be raised, is extent their (i.e. the people involved in this project) entering into a relationship with their environment, was forced into a particular direction because of a set of political and economic factors. What are the political and economic factors which impact on the manner of building houses in the informal residential areas of Grahamstown? Traditional housing in France, for example, differs from region to region and has been shaped over long periods of time by the climate, family structures, the availability of land, modes of production, etc. One finds that large vine-growing families from the Mediterranean South of France live in fairly big villages; individual farmers of Brittany dwell in small, slate-roofed houses which are isolated among enclosed fields; pastoral communities in the Alps undertake seasonal moves up or down the slopes of the mountains and share their space during winter with their cattle. The way in which these families and/or communities have come to shape their lifeworlds, was not exposed to the same kind of determining factors as, for instance, in South Africa in general and in Grahamstown in particular. Notwithstanding political and economic determinants, it is clear that residents of informal houses in the Grahamstown area draw to a large extent from tradition with regards to the kind of shelters which they build (cf. the many mud-and-stick constructions). Similarly the settlement of people impacts on nature. Elements of the environment inform certain choices, but people interpret their natural environment and will erect shelters in terms of these interpretations. In addition there are the issues of how people orientate themselves in terms of important landmarks, what kind of representation they have of the future they are moving towards and which values do they draw from or attribute to their physical environment. The landscape surrounding people, contains and reflects cultural information. Important landmarks express aspects of life: the past, the present and the future. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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Exploring new terrain - tackling a tri-media approach to the 1999 election: an analysis of online coverage of elections by media organisations in their respective countries and recommendations for multi-platform publishing within the South African Broadcasting Corporation to cover the national election
- Authors: Naidoo, Kameshnee
- Date: 1999
- Subjects: South African Broadcasting Corporation , Elections , Journalism -- Political aspects -- South Africa , Mass media -- Political aspects -- South Africa , Internet , Electronic news gathering , Television broadcasting of news -- Political aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3473 , http://hdl.handle.net/10962/d1002928 , South African Broadcasting Corporation , Elections , Journalism -- Political aspects -- South Africa , Mass media -- Political aspects -- South Africa , Internet , Electronic news gathering , Television broadcasting of news -- Political aspects
- Description: This study attempts to analyse the way foreign media organisations have used the Internet to inform, educate and mobilise citizens for participation in their national election. These foreign experiences provide a framework with which to analyse the implications for the SABC as a public broadcaster of the next elections in South Africa. The research was informed by theories of media and democracy. One of the most powerful features of the new technology is its technical ability to facilitate an interactive flow of information. This research examines the concept of cyberdemocracy and the implications for the SABC, especially as it is planning on launching an online election strategy. The democratic roles of journalism and the implications for the SABC are also discussed. As a public service broadcaster, the SABC is bound to educate, inform, and mobilise voters for participation, build community and national identity and scrutinise the poll in the interests of transparency, accountability and fair play. International journalists are advocating a new type of journalism, called public or civic journalism, which combines these roles. This research draws primarily on qualitative research methods, using a case study methodology. It draws upon direct observation and interview methodology in the fieldwork. However, it also uses some quantitative methods in the analysis of the websites and the SABC research.Finally, the research analyses the situation at the SABC and provides recommendations for the election website within this context.
- Full Text:
- Authors: Naidoo, Kameshnee
- Date: 1999
- Subjects: South African Broadcasting Corporation , Elections , Journalism -- Political aspects -- South Africa , Mass media -- Political aspects -- South Africa , Internet , Electronic news gathering , Television broadcasting of news -- Political aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3473 , http://hdl.handle.net/10962/d1002928 , South African Broadcasting Corporation , Elections , Journalism -- Political aspects -- South Africa , Mass media -- Political aspects -- South Africa , Internet , Electronic news gathering , Television broadcasting of news -- Political aspects
- Description: This study attempts to analyse the way foreign media organisations have used the Internet to inform, educate and mobilise citizens for participation in their national election. These foreign experiences provide a framework with which to analyse the implications for the SABC as a public broadcaster of the next elections in South Africa. The research was informed by theories of media and democracy. One of the most powerful features of the new technology is its technical ability to facilitate an interactive flow of information. This research examines the concept of cyberdemocracy and the implications for the SABC, especially as it is planning on launching an online election strategy. The democratic roles of journalism and the implications for the SABC are also discussed. As a public service broadcaster, the SABC is bound to educate, inform, and mobilise voters for participation, build community and national identity and scrutinise the poll in the interests of transparency, accountability and fair play. International journalists are advocating a new type of journalism, called public or civic journalism, which combines these roles. This research draws primarily on qualitative research methods, using a case study methodology. It draws upon direct observation and interview methodology in the fieldwork. However, it also uses some quantitative methods in the analysis of the websites and the SABC research.Finally, the research analyses the situation at the SABC and provides recommendations for the election website within this context.
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Farming against the odds : an examination of the challenges facing farming and rural development in the Eastern Cape province of South Africa
- Authors: Nel, Etienne L , Davies, J
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6715 , http://hdl.handle.net/10962/d1006788
- Description: Recent political transformation in South Africa has laid the basis for significant socioeconomic change. One area in which the greatest socioeconomic disparities are discernable is the agricultural sector and rural development in general. Through the medium of a case study of the Eastern Cape province, the obstacles and opportunities facing the two predominant farming groups —emerging black small-scale farmers and white commercial farmers — are examined. The paper concludes with an examination of the economic potential of the former ‘white' areas to sustain the resettlement of people previously excluded from that land market on racial grounds.
- Full Text:
- Authors: Nel, Etienne L , Davies, J
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6715 , http://hdl.handle.net/10962/d1006788
- Description: Recent political transformation in South Africa has laid the basis for significant socioeconomic change. One area in which the greatest socioeconomic disparities are discernable is the agricultural sector and rural development in general. Through the medium of a case study of the Eastern Cape province, the obstacles and opportunities facing the two predominant farming groups —emerging black small-scale farmers and white commercial farmers — are examined. The paper concludes with an examination of the economic potential of the former ‘white' areas to sustain the resettlement of people previously excluded from that land market on racial grounds.
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Fish population dynamics in a temporarily open/closed South African estuary
- Cowley, Paul D (Paul Denfer), 1964-
- Authors: Cowley, Paul D (Paul Denfer), 1964-
- Date: 1999
- Subjects: Fish populations Estuarine ecology -- South Africa -- Eastern Cape Estuarine fishes -- Ecology -- South Africa Fish populations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5354 , http://hdl.handle.net/10962/d1008543
- Description: The primary aim of this study was to investigate the population dynamics of the fishes associated with a small (17.5 hectares) temporarily open/closed estuary on the south east coast of South Africa. The results are based on the findings of an intensive sampling programme conducted over a period of four years in the East Kleinemonde estuary (33° 32' S : 27° 03' E). By adopting a quantitative approach, this study addresses the need for information on estuarine-associated fish population sizes, standing stock (biomass) estimates and productivity. The ichthyoplankton assemblage in the surf zone adjacent to the mouth of the estuary was dominated by postflexion larvae representing at least 21 taxa in 14 families. Rhabdosargus holubi of sizes ranging between 9 mm and 21 mm BL was the most abundant species with a mean density of 7.3 individuals per 100 m'. This species, which accounted for 77.6% of the catch composition, was recorded throughout the year but revealed a distinct peak in abundance in spring (August - September). The ichthyofaunal community within the East Kleinemonde estuary was dominated by juvenile marine-spawning species and typical of a warm temperate southern African estuary. A total of 30 species in 17 families was recorded, including the endangered estuarine pipefish Syngnathus watermeyeri. Multivariate analyses (classification and ordination) of the catch assemblages revealed a high degree of similarity (> 70%) throughout the estuary, with two distinct groups being identified on the basis of substratum type. The sampling stations near the mouth with a sandy substratum were distinguished from all other sampling sites in the estuary. The dominant estuarine-spawning species were represented by all life-history stages, suggesting that they bred successfully in the estuary. This group was numerically and gravimetrically dominated by the two zooplanktivorous shoaling species Gilchristella aestuaria and Atherina breviceps with density extrapolated population size estimates of 420 973 and 198 275 individuals, and biomass estimates of 1.6 and 0.6 g m⁻² respectively. The total population size of all estuarine-spawning species with a mean biomass 00.4 g m⁻² was estimated at 754 217 individuals. Population size estimates of the marine-spawning species were calculated using data obtained from three independent mark-recapture experiments. The assumptions for the mark-recapture analyses were adequately met and it was concluded that the techniques provided reliable estimates of population size. However, estimates obtained from density extrapolation revealed enormous variability and were considered to be unreliable. The total population size was estimated at 63 342, 18 592 and 13 5 192 during the three mark-recapture experiments respectively. The numerically dominant species during all three experiments was Rhabdosargus holubi. Biomass production of the marine-spawning species was evaluated over a 123 day census period when population sizes and estimates of growth rates were known. Productivity for all fishes with a standing stock of 26.2 g m⁻² was calculated at 4.5 g m⁻² month01 Rhabdosargus holubi accounted for more than 75% of the total marine fish productivity. This study draws attention to the success of Rhabdosargus holubi in the East Kleinemonde estuary, which is ascribed to aspects of its biology. These include an extended breeding season, the ability to recruit into the estuary under adverse open mouth conditions and its omnivorous food habits. The dominance of this migratory species suggests that it plays an important role in the transfer of energy to the coastal marine environment when the mouth of the East Kleinemonde estuary opens. Predation by birds and a dominant piscivorous fish (Lichia amia) was quantitatively assessed over a period of two years. Monthly food consumption by all piscivorous birds revealed large temporal variability, ranging from 32 to 466 kg month-I An unusual invasion of Cape cormorants during the winter of 1994 accounted for large scale mortality (2246 kg of fish) over a relatively short period. The predatory impact of this episodic event was reflected in the findings of the fish mark-recapture experiments, which revealed a 70% reduction in the total population of marine-spawning fishes (above a certain minimum size) in the estuary subsequent to this invasion. Monthly food consumption by the Lichia amia population in the estuary was calculated at 68 and 58 kg month-I for two distinct time periods when the population size was known. These findings suggest that this species is the top piscivorous predator in the East Kleinemonde estuary. Finally, the findings of this study highlight the temporal variability of fish populations within a single estuary. It is suggested that predation and estuary mouth conditions are the main factors influencing the abundance (and its variability) of individual species in the East Kleinemonde estuary.
- Full Text:
- Authors: Cowley, Paul D (Paul Denfer), 1964-
- Date: 1999
- Subjects: Fish populations Estuarine ecology -- South Africa -- Eastern Cape Estuarine fishes -- Ecology -- South Africa Fish populations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5354 , http://hdl.handle.net/10962/d1008543
- Description: The primary aim of this study was to investigate the population dynamics of the fishes associated with a small (17.5 hectares) temporarily open/closed estuary on the south east coast of South Africa. The results are based on the findings of an intensive sampling programme conducted over a period of four years in the East Kleinemonde estuary (33° 32' S : 27° 03' E). By adopting a quantitative approach, this study addresses the need for information on estuarine-associated fish population sizes, standing stock (biomass) estimates and productivity. The ichthyoplankton assemblage in the surf zone adjacent to the mouth of the estuary was dominated by postflexion larvae representing at least 21 taxa in 14 families. Rhabdosargus holubi of sizes ranging between 9 mm and 21 mm BL was the most abundant species with a mean density of 7.3 individuals per 100 m'. This species, which accounted for 77.6% of the catch composition, was recorded throughout the year but revealed a distinct peak in abundance in spring (August - September). The ichthyofaunal community within the East Kleinemonde estuary was dominated by juvenile marine-spawning species and typical of a warm temperate southern African estuary. A total of 30 species in 17 families was recorded, including the endangered estuarine pipefish Syngnathus watermeyeri. Multivariate analyses (classification and ordination) of the catch assemblages revealed a high degree of similarity (> 70%) throughout the estuary, with two distinct groups being identified on the basis of substratum type. The sampling stations near the mouth with a sandy substratum were distinguished from all other sampling sites in the estuary. The dominant estuarine-spawning species were represented by all life-history stages, suggesting that they bred successfully in the estuary. This group was numerically and gravimetrically dominated by the two zooplanktivorous shoaling species Gilchristella aestuaria and Atherina breviceps with density extrapolated population size estimates of 420 973 and 198 275 individuals, and biomass estimates of 1.6 and 0.6 g m⁻² respectively. The total population size of all estuarine-spawning species with a mean biomass 00.4 g m⁻² was estimated at 754 217 individuals. Population size estimates of the marine-spawning species were calculated using data obtained from three independent mark-recapture experiments. The assumptions for the mark-recapture analyses were adequately met and it was concluded that the techniques provided reliable estimates of population size. However, estimates obtained from density extrapolation revealed enormous variability and were considered to be unreliable. The total population size was estimated at 63 342, 18 592 and 13 5 192 during the three mark-recapture experiments respectively. The numerically dominant species during all three experiments was Rhabdosargus holubi. Biomass production of the marine-spawning species was evaluated over a 123 day census period when population sizes and estimates of growth rates were known. Productivity for all fishes with a standing stock of 26.2 g m⁻² was calculated at 4.5 g m⁻² month01 Rhabdosargus holubi accounted for more than 75% of the total marine fish productivity. This study draws attention to the success of Rhabdosargus holubi in the East Kleinemonde estuary, which is ascribed to aspects of its biology. These include an extended breeding season, the ability to recruit into the estuary under adverse open mouth conditions and its omnivorous food habits. The dominance of this migratory species suggests that it plays an important role in the transfer of energy to the coastal marine environment when the mouth of the East Kleinemonde estuary opens. Predation by birds and a dominant piscivorous fish (Lichia amia) was quantitatively assessed over a period of two years. Monthly food consumption by all piscivorous birds revealed large temporal variability, ranging from 32 to 466 kg month-I An unusual invasion of Cape cormorants during the winter of 1994 accounted for large scale mortality (2246 kg of fish) over a relatively short period. The predatory impact of this episodic event was reflected in the findings of the fish mark-recapture experiments, which revealed a 70% reduction in the total population of marine-spawning fishes (above a certain minimum size) in the estuary subsequent to this invasion. Monthly food consumption by the Lichia amia population in the estuary was calculated at 68 and 58 kg month-I for two distinct time periods when the population size was known. These findings suggest that this species is the top piscivorous predator in the East Kleinemonde estuary. Finally, the findings of this study highlight the temporal variability of fish populations within a single estuary. It is suggested that predation and estuary mouth conditions are the main factors influencing the abundance (and its variability) of individual species in the East Kleinemonde estuary.
- Full Text:
Forms and techniques of modern painting
- Authors: Ning, Cui
- Date: 1999
- Subjects: Painting, Modern
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2418 , http://hdl.handle.net/10962/d1002214
- Description: In this thesis, I have made an attempt to discuss and comment on oil painting from the "angle of concepts, forms, both traditional as well as more recent techniques of modern painting
- Full Text:
- Authors: Ning, Cui
- Date: 1999
- Subjects: Painting, Modern
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2418 , http://hdl.handle.net/10962/d1002214
- Description: In this thesis, I have made an attempt to discuss and comment on oil painting from the "angle of concepts, forms, both traditional as well as more recent techniques of modern painting
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Glimpsing the balance between earth and sky: a meeting ground for postmodernism and Christianity in four selected novels by Jeanette Winterson and John Irving
- Authors: Edwards, Ross Stephen
- Date: 1999
- Subjects: Postmodernism -- Religious aspects Winterson, Jeanette, 1959- Irving, John, 1942- Postmodernism (Literature)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2186 , http://hdl.handle.net/10962/d1002228
- Description: The phrase “glimpsing the balance between earth and sky” in the thesis title is taken from Jeanette Winterson’s Oranges Are Not the Only Fruit. In this novel, the central character Jeanette believes she has glimpsed the possibility that human relationships can find their mirror in the relationship with God, as she understands the divine Other. This glimpse has set her wandering, trying to find such a balance. This examination of four selected novels by Jeanette Winterson and John Irving shows that for Irving, “glimpsing the balance” means in part, giving voice to a strongly “Christian” view of humankind and human nature but in an age where the prevailing intellectual worldview is strongly sceptical of any Grand Narrative. The “voice” expressed in Irving’s work has to be situated, like Winterson’s, as one among many possibilities. Irving’s voice is itself masked as different, other/Other, freakish, in the narrative worlds he creates. Through his use of grotesque comedy as a vehicle for deeper philosophical concerns, Irving asks us: What after all in the postmodern world is the main show? This thesis argues that if Winterson and Irving are testing or re-presenting a Christian worldview in a postmodern context, than they are asking whether Christianity is capable of assimilating and rising above the worst circumstances the world, writer, and life can throw at it. In Oranges Are Not the Only Fruit, Winterson tells a story of “forbidden love”, posed as a direct challenge to the prevailing way of knowing in her character’s community. In Gut Symmetries, she expands this challenge by employing the insights of quantum physics to make sense of the complexities raised by a triangular love relationship. Irving offers the story of Owen in A Prayer for Owen Meany as the kind of story which might possibly make a believer out of him; in short, that he would have to be a witness to some kind of miracle, something utterly inexplicable. In A Son of the Circus Irving narrates the quest for identity undertaken by an Indian doctor who is in every way a Displaced Person – the condition, he implies, of anyone who purports to find their piece of the truth. The theoretical concerns of the postmodern project are examined through Lawrence Cahoone’s argument that postmodern writing offers criticism of: presence, origin, unity and transcendence through an analytical strategy of constitutive otherness. In each of their texts, Irving and Winterson are seen to use these four critical elements and to offer a postmodern strategy of re-presenting meaning through “constitutive otherness”. Both writers also employ a strategy of historiographic metafiction (as defined by Linda Hutcheon) as a means of constructing and re-presenting their narrated stories. Postmodern paradox is compatible with what could be called a Christian plan for living, if the latter is in turn given an appropriate 1990s interpretation. The selected novels by Winterson and Irving are offered as contemporary evidence for this view. This thesis argues that the connection between postmodernism and other worldviews, particularly Christianity, is found in both projects’ process of making meanings through encounters with an other/Other.
- Full Text:
- Authors: Edwards, Ross Stephen
- Date: 1999
- Subjects: Postmodernism -- Religious aspects Winterson, Jeanette, 1959- Irving, John, 1942- Postmodernism (Literature)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2186 , http://hdl.handle.net/10962/d1002228
- Description: The phrase “glimpsing the balance between earth and sky” in the thesis title is taken from Jeanette Winterson’s Oranges Are Not the Only Fruit. In this novel, the central character Jeanette believes she has glimpsed the possibility that human relationships can find their mirror in the relationship with God, as she understands the divine Other. This glimpse has set her wandering, trying to find such a balance. This examination of four selected novels by Jeanette Winterson and John Irving shows that for Irving, “glimpsing the balance” means in part, giving voice to a strongly “Christian” view of humankind and human nature but in an age where the prevailing intellectual worldview is strongly sceptical of any Grand Narrative. The “voice” expressed in Irving’s work has to be situated, like Winterson’s, as one among many possibilities. Irving’s voice is itself masked as different, other/Other, freakish, in the narrative worlds he creates. Through his use of grotesque comedy as a vehicle for deeper philosophical concerns, Irving asks us: What after all in the postmodern world is the main show? This thesis argues that if Winterson and Irving are testing or re-presenting a Christian worldview in a postmodern context, than they are asking whether Christianity is capable of assimilating and rising above the worst circumstances the world, writer, and life can throw at it. In Oranges Are Not the Only Fruit, Winterson tells a story of “forbidden love”, posed as a direct challenge to the prevailing way of knowing in her character’s community. In Gut Symmetries, she expands this challenge by employing the insights of quantum physics to make sense of the complexities raised by a triangular love relationship. Irving offers the story of Owen in A Prayer for Owen Meany as the kind of story which might possibly make a believer out of him; in short, that he would have to be a witness to some kind of miracle, something utterly inexplicable. In A Son of the Circus Irving narrates the quest for identity undertaken by an Indian doctor who is in every way a Displaced Person – the condition, he implies, of anyone who purports to find their piece of the truth. The theoretical concerns of the postmodern project are examined through Lawrence Cahoone’s argument that postmodern writing offers criticism of: presence, origin, unity and transcendence through an analytical strategy of constitutive otherness. In each of their texts, Irving and Winterson are seen to use these four critical elements and to offer a postmodern strategy of re-presenting meaning through “constitutive otherness”. Both writers also employ a strategy of historiographic metafiction (as defined by Linda Hutcheon) as a means of constructing and re-presenting their narrated stories. Postmodern paradox is compatible with what could be called a Christian plan for living, if the latter is in turn given an appropriate 1990s interpretation. The selected novels by Winterson and Irving are offered as contemporary evidence for this view. This thesis argues that the connection between postmodernism and other worldviews, particularly Christianity, is found in both projects’ process of making meanings through encounters with an other/Other.
- Full Text:
Graphicacy as a form of communication
- Authors: Wilmot, P Dianne
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6091 , http://hdl.handle.net/10962/d1008613
- Description: Children of today inhabit a multi-dimensional world and in order to communicate effectively in it they need the ability to utilise four forms of communication namely, oracy, literacy, numeracy and graphicacy. Communicating in graphic form requires an ability to both encode and decode spatial information using symbols which requires the utilisation and application of spatial perceptual skills and concepts. The draft Curriculum Framework for General and Further Education and Training identifies graphic literacy as one of the critical outcomes of the new South African curriculum. Spatial information about the environment is most frequently communicated in the graphic mode. Yet if graphicacy is to be recognised as an essential mode of communication and, as such, a vital element in education, then we need to seek ways of developing and introducing an explicit and critical pedagogy in our schools to foster the development of graphic and critical graphic literacy. But first, the skills and concepts integral to graphicacy need to be identified and understood. This article provides a framework for thinking about graphicacy as a form of communication in the General Education and Training (GET) band, the compulsory component of South African education (Grades 1-9).
- Full Text: false
- Authors: Wilmot, P Dianne
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6091 , http://hdl.handle.net/10962/d1008613
- Description: Children of today inhabit a multi-dimensional world and in order to communicate effectively in it they need the ability to utilise four forms of communication namely, oracy, literacy, numeracy and graphicacy. Communicating in graphic form requires an ability to both encode and decode spatial information using symbols which requires the utilisation and application of spatial perceptual skills and concepts. The draft Curriculum Framework for General and Further Education and Training identifies graphic literacy as one of the critical outcomes of the new South African curriculum. Spatial information about the environment is most frequently communicated in the graphic mode. Yet if graphicacy is to be recognised as an essential mode of communication and, as such, a vital element in education, then we need to seek ways of developing and introducing an explicit and critical pedagogy in our schools to foster the development of graphic and critical graphic literacy. But first, the skills and concepts integral to graphicacy need to be identified and understood. This article provides a framework for thinking about graphicacy as a form of communication in the General Education and Training (GET) band, the compulsory component of South African education (Grades 1-9).
- Full Text: false
Guy Butler (obituary)
- Authors: Wright, Laurence
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:7052 , http://hdl.handle.net/10962/d1007411
- Description: An obituary focusing on Guy Butler's Shakespearean preoccupations. The 1999/2000 volume of Shakespeare in Southern Africa only appeared in 2001. The Butler obituary was included as a 'stop-press' item as the volume went to print, which accounts for the apparent anomaly between the date of publication and the date of Guy Butler's death.
- Full Text:
- Authors: Wright, Laurence
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:7052 , http://hdl.handle.net/10962/d1007411
- Description: An obituary focusing on Guy Butler's Shakespearean preoccupations. The 1999/2000 volume of Shakespeare in Southern Africa only appeared in 2001. The Butler obituary was included as a 'stop-press' item as the volume went to print, which accounts for the apparent anomaly between the date of publication and the date of Guy Butler's death.
- Full Text: