A critical investigation into course development for the preparation of school leaders
- Authors: McFarlane, Johannes
- Date: 2000
- Subjects: Educational leadership Educational leadership -- South Africa Action research in education School principals -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1929 , http://hdl.handle.net/10962/d1007596
- Description: Many schools in South Africa suffer from the consequences of bad leadership and management practices. A contributing factor to this problem is the inadequate preparation of school leaders for the wide variety of challenges facing them. This study formed part of a three-year project to develop a preparation programme for school leaders in the Southern Cape area of South Africa. Its aims focussed on the identification of principles for the design of preparation programmes leading to improvements in practice. Twelve teachers and principals participated in the project. They enrolled for a programme in school leadership designed and offered by the University of Port Elizabeth in consultation and cooperation with the Southern Cape Learning Resource Unit in George. Five sources were utilized for the provision of data: - The existing literature on the development of preparation programmes; - The group of twelve participants of the programme; - The four school principals in the group who acted as a focus group; - The staff and certain documents from the schools where these four principals are employed; - Local stakeholders with an interest in the success of the programme. Research methods typical of the interpretive tradition were utilized in orderto arrive at a better understanding of the needs of participants and of those elements of programmes which have the greatest impact on practice. Among the insights to have emerged from the study are the following: - The fact that the preparation of school leaders is a complex and multifaceted process which is enhanced by variety, continuous interaction between presenters and participants, flexibilityt o respond to changing needs and contexts, and an ongoing implementation in and feedback from practice ; - The central role played in the professional and academic growth of participants by individuals and groups around them; - The importance of action research as a tool in the accomplishment of a variety of goals in the preparation of school leaders. The main contributions of this study include: - A framework for the development of preparation programmes, ensuring the inclusion of a wide range of elements enhancing the effectiveness of the course; - A framework for the establishment of professional networks supporting participants in preparation programmes.
- Full Text:
- Date Issued: 2000
- Authors: McFarlane, Johannes
- Date: 2000
- Subjects: Educational leadership Educational leadership -- South Africa Action research in education School principals -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1929 , http://hdl.handle.net/10962/d1007596
- Description: Many schools in South Africa suffer from the consequences of bad leadership and management practices. A contributing factor to this problem is the inadequate preparation of school leaders for the wide variety of challenges facing them. This study formed part of a three-year project to develop a preparation programme for school leaders in the Southern Cape area of South Africa. Its aims focussed on the identification of principles for the design of preparation programmes leading to improvements in practice. Twelve teachers and principals participated in the project. They enrolled for a programme in school leadership designed and offered by the University of Port Elizabeth in consultation and cooperation with the Southern Cape Learning Resource Unit in George. Five sources were utilized for the provision of data: - The existing literature on the development of preparation programmes; - The group of twelve participants of the programme; - The four school principals in the group who acted as a focus group; - The staff and certain documents from the schools where these four principals are employed; - Local stakeholders with an interest in the success of the programme. Research methods typical of the interpretive tradition were utilized in orderto arrive at a better understanding of the needs of participants and of those elements of programmes which have the greatest impact on practice. Among the insights to have emerged from the study are the following: - The fact that the preparation of school leaders is a complex and multifaceted process which is enhanced by variety, continuous interaction between presenters and participants, flexibilityt o respond to changing needs and contexts, and an ongoing implementation in and feedback from practice ; - The central role played in the professional and academic growth of participants by individuals and groups around them; - The importance of action research as a tool in the accomplishment of a variety of goals in the preparation of school leaders. The main contributions of this study include: - A framework for the development of preparation programmes, ensuring the inclusion of a wide range of elements enhancing the effectiveness of the course; - A framework for the establishment of professional networks supporting participants in preparation programmes.
- Full Text:
- Date Issued: 2000
Designing and making a difference: an exploration of technology education for rural school teachers
- Authors: Schäfer, Marc
- Date: 2000
- Subjects: Technology -- Study and teaching -- South Africa -- Eastern Cape Technology -- Study and teaching -- South Africa Rural schools -- South Africa -- Eastern Cape Education, Rural -- South Africa Winterberg schools trust
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1491 , http://hdl.handle.net/10962/d1003372
- Description: This qualitative study focused on a Technology Education programme for farm school teachers in the Eastern Cape province of South Africa. These teachers were faced with the challenge of incorporating Technology Education into their curriculum. The study was conducted within the context of an investigation into the conceptual nature of technology and an exploration of the theoretical underpinnings of Technology Education within both the international and South African context. Technology Education is being introduced into the South African curriculum against a background of educational transformation and the building of capacity to solve real life problems. This calls for a curriculum that will empower learners to be innovative, creative and skilled problem solvers. The introduction and incorporation of Technoiogy Education into the school curriculum poses a formidable challenge to farm schools in particular. Their unique history of neglect and legacy of underqualified teachers has made the introduction of any curriculum innovation process very difficult and challenging. This study analyses how an introductory Technology Education programme for farm school teachers in the Winterberg area of the Eastern Cape impacted~ on the teachers' professional and personal lives. It shows the importance of developing teclpological skills in conjunction with life skills in cO.ntributing to the empowerment, both in the work place and in the wider context, of rural school teachers. It highlights the need for supportive in-service education programmes and strengthens the argument for an integrative and mulitidisciplinary approach to the introduction of Technology Education in farm schools. Data was collected by means of questionnaires, interviews and photographs.
- Full Text:
- Date Issued: 2000
- Authors: Schäfer, Marc
- Date: 2000
- Subjects: Technology -- Study and teaching -- South Africa -- Eastern Cape Technology -- Study and teaching -- South Africa Rural schools -- South Africa -- Eastern Cape Education, Rural -- South Africa Winterberg schools trust
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1491 , http://hdl.handle.net/10962/d1003372
- Description: This qualitative study focused on a Technology Education programme for farm school teachers in the Eastern Cape province of South Africa. These teachers were faced with the challenge of incorporating Technology Education into their curriculum. The study was conducted within the context of an investigation into the conceptual nature of technology and an exploration of the theoretical underpinnings of Technology Education within both the international and South African context. Technology Education is being introduced into the South African curriculum against a background of educational transformation and the building of capacity to solve real life problems. This calls for a curriculum that will empower learners to be innovative, creative and skilled problem solvers. The introduction and incorporation of Technoiogy Education into the school curriculum poses a formidable challenge to farm schools in particular. Their unique history of neglect and legacy of underqualified teachers has made the introduction of any curriculum innovation process very difficult and challenging. This study analyses how an introductory Technology Education programme for farm school teachers in the Winterberg area of the Eastern Cape impacted~ on the teachers' professional and personal lives. It shows the importance of developing teclpological skills in conjunction with life skills in cO.ntributing to the empowerment, both in the work place and in the wider context, of rural school teachers. It highlights the need for supportive in-service education programmes and strengthens the argument for an integrative and mulitidisciplinary approach to the introduction of Technology Education in farm schools. Data was collected by means of questionnaires, interviews and photographs.
- Full Text:
- Date Issued: 2000
The psychological role of homoeroticism in the spiritual growth of priests: a study of individuation processes and homoerotic sexualities
- Authors: Taute, Harold Graeme
- Date: 2000
- Subjects: Homosexuality -- Psychological aspects Homosexuality -- Religious aspects -- Christianity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3069 , http://hdl.handle.net/10962/d1002578
- Description: The study explored the psychological role of homoeroticism in the spiritual growth of priests, using Grounded Theory and James Fowler’s stages of faith development as the basis for the research methodology. Three Anglican priests were interviewed using a semi-structured interview format. The research interview combined Fowler’s Faith Development Interview Guide and a semi-structured interview in order to ascertain the priests’ level of spiritual development, as well as to explore their experience of the homoerotic component to their sexuality, and its influence on their spiritual growth. The interviews and iterative analysis focussed on four major questions: (1) Are priests who experience and actively work at integrating the homoerotic aspect to themselves assisted thereby in their spiritual growth, and if so, how might this be accounted for?; (2) Following Fowler’s model of spiritual development, what processes characterise each priest’s approach to meaning-creation in their lives?; (3) Following Fowler’s model, can the psychological work of engaging with and accepting homoeroticism be conceived of as serving an initiatory function in the emergence of new processes of meaning-creation?; (4) What role does homoeroticism serve in the spiritual growth of priests? The interpretative phase consisted of three stages. A grounded theory analysis of each interview was undertaken, developing a model for understanding the role of homoeroticism in spiritual growth. In the second stage, the priest’s level of spiritual development was ascertained, using Fowler’s Faith Development Guide. The third stage linked each participant’s level of spiritual development (in Fowler’s terms) with their core stories regarding experiences, meanings, and roles of homoeroticism. Finally, an integrative theory of the role of homoeroticism in spiritual growth was developed, using Jungian and post-Jungian theory as a basis for the discussion. The results suggested that homoeroticism did not play any role in spiritual growth and individuation separate to the manner in which it was experienced as having been constructed by society and the Church, and separate to the manner in which each priest in the study expressed, experienced, or engaged with it. In this context the experience of homoeroticism appeared to play a diversity of roles, including representing the collective and personal shadow, the archetypal anima/animus, the archetypal puer/senex constellation, the transcendent function, and thereby, as an expression of these roles, contribute to the emergence of new processes of meaning-creation in the spiritual growth and individuation of priests.
- Full Text:
- Date Issued: 2000
- Authors: Taute, Harold Graeme
- Date: 2000
- Subjects: Homosexuality -- Psychological aspects Homosexuality -- Religious aspects -- Christianity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3069 , http://hdl.handle.net/10962/d1002578
- Description: The study explored the psychological role of homoeroticism in the spiritual growth of priests, using Grounded Theory and James Fowler’s stages of faith development as the basis for the research methodology. Three Anglican priests were interviewed using a semi-structured interview format. The research interview combined Fowler’s Faith Development Interview Guide and a semi-structured interview in order to ascertain the priests’ level of spiritual development, as well as to explore their experience of the homoerotic component to their sexuality, and its influence on their spiritual growth. The interviews and iterative analysis focussed on four major questions: (1) Are priests who experience and actively work at integrating the homoerotic aspect to themselves assisted thereby in their spiritual growth, and if so, how might this be accounted for?; (2) Following Fowler’s model of spiritual development, what processes characterise each priest’s approach to meaning-creation in their lives?; (3) Following Fowler’s model, can the psychological work of engaging with and accepting homoeroticism be conceived of as serving an initiatory function in the emergence of new processes of meaning-creation?; (4) What role does homoeroticism serve in the spiritual growth of priests? The interpretative phase consisted of three stages. A grounded theory analysis of each interview was undertaken, developing a model for understanding the role of homoeroticism in spiritual growth. In the second stage, the priest’s level of spiritual development was ascertained, using Fowler’s Faith Development Guide. The third stage linked each participant’s level of spiritual development (in Fowler’s terms) with their core stories regarding experiences, meanings, and roles of homoeroticism. Finally, an integrative theory of the role of homoeroticism in spiritual growth was developed, using Jungian and post-Jungian theory as a basis for the discussion. The results suggested that homoeroticism did not play any role in spiritual growth and individuation separate to the manner in which it was experienced as having been constructed by society and the Church, and separate to the manner in which each priest in the study expressed, experienced, or engaged with it. In this context the experience of homoeroticism appeared to play a diversity of roles, including representing the collective and personal shadow, the archetypal anima/animus, the archetypal puer/senex constellation, the transcendent function, and thereby, as an expression of these roles, contribute to the emergence of new processes of meaning-creation in the spiritual growth and individuation of priests.
- Full Text:
- Date Issued: 2000
The role of black consciousness in the experience of being black in South Africa: the shaping of the identity of two members of AZAPO
- Authors: Mnguni, Mphikeleli Matthew
- Date: 2000
- Subjects: Black consciousness , Azanian People's Organization , Identity (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3022 , http://hdl.handle.net/10962/d1002531 , Black consciousness , Azanian People's Organization , Identity (Psychology)
- Description: The research attempts to understand the role Black Consciousness (BC) plays in the identity of blacks in South Africa by exploring and describing the experience of self-identity in the life-history context of two members of AZAPO, a BC organisation. The literature review explores the work of Biko, Manganyi, and Fanon with a view to understanding whether and how it might be claimed that BC galvanises the black person to discard the crippling fear of colonialism which inflicts feelings of inferiority, and to rise up to claim his/her rightful place in community life. To explore the philosophical assumptions made in the literature review, a qualitative study was conducted. Interviews were conducted with two black adults who have adopted BC philosophy. Three separate in-depth phenomenological interviews were conducted which yielded a description of the experiences of each respondent. A tape recorder was used to record the interviews and they were transcribed for analysis. A thematic analysis was conducted using the reading guide method. The material was thematised using the following questions: What biographical factors are seen as being important prior to the respondent becoming black conscious? How did the participant come to realise his/her self-identity as problematic? How did the process of adopting BC change the participant’s selfidentity? The results indicate that participants became aware very early in their lives and prior to adopting BC, that their own supportive and cohesive family cultures were at odds with the surrounding social context. Early experiences of this were initially unintelligible but impressionable. BC in this sense provided a framework for understanding and engaging with these experiences. The study shows that the adoption of BC helped to make sense of experiences of community isolation, discrimination, oppression and provided them with a mode of engaging practically with these issues. It was not adopted from a perspective of poor self-esteem or other such purely personal characteristics which may have been expected on the basis of literature in the area. BC was adopted as a way of understanding the relationship between their communities or backgrounds and the broader social environment and if there was a ‘healing’ project it was at this level.However, the study did show the close relationship between individual and social well-being that emerged as intrinsic both to the philosophy of BC and the lives of these individuals. This was shown to play out in the commitment of these individuals to the development of black communities and in their tying of their own destinies to the destiny of the oppressed black people in general. These and other issues which emerged in the two case studies are discussed in relation to the literature in the area.
- Full Text:
- Date Issued: 2000
- Authors: Mnguni, Mphikeleli Matthew
- Date: 2000
- Subjects: Black consciousness , Azanian People's Organization , Identity (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3022 , http://hdl.handle.net/10962/d1002531 , Black consciousness , Azanian People's Organization , Identity (Psychology)
- Description: The research attempts to understand the role Black Consciousness (BC) plays in the identity of blacks in South Africa by exploring and describing the experience of self-identity in the life-history context of two members of AZAPO, a BC organisation. The literature review explores the work of Biko, Manganyi, and Fanon with a view to understanding whether and how it might be claimed that BC galvanises the black person to discard the crippling fear of colonialism which inflicts feelings of inferiority, and to rise up to claim his/her rightful place in community life. To explore the philosophical assumptions made in the literature review, a qualitative study was conducted. Interviews were conducted with two black adults who have adopted BC philosophy. Three separate in-depth phenomenological interviews were conducted which yielded a description of the experiences of each respondent. A tape recorder was used to record the interviews and they were transcribed for analysis. A thematic analysis was conducted using the reading guide method. The material was thematised using the following questions: What biographical factors are seen as being important prior to the respondent becoming black conscious? How did the participant come to realise his/her self-identity as problematic? How did the process of adopting BC change the participant’s selfidentity? The results indicate that participants became aware very early in their lives and prior to adopting BC, that their own supportive and cohesive family cultures were at odds with the surrounding social context. Early experiences of this were initially unintelligible but impressionable. BC in this sense provided a framework for understanding and engaging with these experiences. The study shows that the adoption of BC helped to make sense of experiences of community isolation, discrimination, oppression and provided them with a mode of engaging practically with these issues. It was not adopted from a perspective of poor self-esteem or other such purely personal characteristics which may have been expected on the basis of literature in the area. BC was adopted as a way of understanding the relationship between their communities or backgrounds and the broader social environment and if there was a ‘healing’ project it was at this level.However, the study did show the close relationship between individual and social well-being that emerged as intrinsic both to the philosophy of BC and the lives of these individuals. This was shown to play out in the commitment of these individuals to the development of black communities and in their tying of their own destinies to the destiny of the oppressed black people in general. These and other issues which emerged in the two case studies are discussed in relation to the literature in the area.
- Full Text:
- Date Issued: 2000
Water requirements and distribution of Ammophila arenaria and Scaevola plumieri on South African coastal dunes
- Authors: Peter, Craig Ingram
- Date: 2000
- Subjects: Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4219 , http://hdl.handle.net/10962/d1003788 , Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Description: Phenomenological models are presented which predicts transpiration rates (E) of individual leaves of Scaevola plumieri, an indigenous dune pioneer, and Ammophila arenaria, an exotic grass species introduced to stabilise mobile sand. In both cases E is predictably related to atmospheric vapour pressure deficit (VPD). VPD is calculated from measurements of ambient temperature and humidity, hence, where these two environmental variables are known, E can be calculated. Possible physiological reasons for the relationships of E to VPD in both species are discussed. Scaling from measurements of E at the leaf level to the canopy level is achieved by summing the leaf area of the canopy in question. E is predicted for the entire canopy leaf area by extrapolation to this larger leaf area. Predicted transpiration rates of individual shoot within the canopy were tested gravimetrically and shown to be accurate in the case of S. plumieri, but less so in the case of A. arenaria. Using this model, the amount of water used by a known area of sand dune is shown to be less than the rainfall input in the case of S. plumieri in wet and dry years. The water use of A. arenaria exceeds rainfall in the low-rainfall year of 1995, while in 1998 rainfall input is slightly higher than water extraction by the plants. Using a geographic information system (GIS), regional maps (surfaces) of transpiration were calculated from surfaces of mean monthly temperature and mean monthly relative humidity. Monthly surfaces of transpiration were subtracted from the monthly median rainfall to produce a surface of mean monthly water deficit. Areas of water surpluses along the coast correspond with the recorded distribution of both species in the seasons that the plants are most actively growing and reproducing. This suggests that unfavourable water availability during these two species growth periods limit their distributions along the coast. In addition to unfavourable water deficits, additional climatic variables that may be important in limiting the distribution of these two species were investigated using a discriminant function analysis.
- Full Text:
- Date Issued: 2000
- Authors: Peter, Craig Ingram
- Date: 2000
- Subjects: Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4219 , http://hdl.handle.net/10962/d1003788 , Scaevola plumieri , Sand dune plants , Sand dune planting , Plants -- Transpiration , Sandworts , Plant-water relationships , Evapotranspiration , Plants, Effect of heat on
- Description: Phenomenological models are presented which predicts transpiration rates (E) of individual leaves of Scaevola plumieri, an indigenous dune pioneer, and Ammophila arenaria, an exotic grass species introduced to stabilise mobile sand. In both cases E is predictably related to atmospheric vapour pressure deficit (VPD). VPD is calculated from measurements of ambient temperature and humidity, hence, where these two environmental variables are known, E can be calculated. Possible physiological reasons for the relationships of E to VPD in both species are discussed. Scaling from measurements of E at the leaf level to the canopy level is achieved by summing the leaf area of the canopy in question. E is predicted for the entire canopy leaf area by extrapolation to this larger leaf area. Predicted transpiration rates of individual shoot within the canopy were tested gravimetrically and shown to be accurate in the case of S. plumieri, but less so in the case of A. arenaria. Using this model, the amount of water used by a known area of sand dune is shown to be less than the rainfall input in the case of S. plumieri in wet and dry years. The water use of A. arenaria exceeds rainfall in the low-rainfall year of 1995, while in 1998 rainfall input is slightly higher than water extraction by the plants. Using a geographic information system (GIS), regional maps (surfaces) of transpiration were calculated from surfaces of mean monthly temperature and mean monthly relative humidity. Monthly surfaces of transpiration were subtracted from the monthly median rainfall to produce a surface of mean monthly water deficit. Areas of water surpluses along the coast correspond with the recorded distribution of both species in the seasons that the plants are most actively growing and reproducing. This suggests that unfavourable water availability during these two species growth periods limit their distributions along the coast. In addition to unfavourable water deficits, additional climatic variables that may be important in limiting the distribution of these two species were investigated using a discriminant function analysis.
- Full Text:
- Date Issued: 2000
Characterization of amide bond hydrolysis in novel hydantoinase-producing bacteria
- Authors: Skepu, Zoleka G
- Date: 2000
- Subjects: Amides , Hydrolysis , Hydantoin , Imides
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3911 , http://hdl.handle.net/10962/d1003970 , Amides , Hydrolysis , Hydantoin , Imides
- Description: This thesis describes a series of investigations into the amide bond-hydrolyzing activity of bacterial strains RU-KM1, RU-KM3L, RU-KM3S, and RU-OR, which were previously isolated for their ability to hydrolyze hydantoins to amino acids. The main aim of the study was to develop biotransformations with potential application in the production of enantiomerically pure amino acids and related compounds. Several compounds may be used as substrates by biocatalysts for the production of amino acids, such as hydantoins, amino nitriles, and amides. These compounds are not only important for amino acid production, but they may be used for production of other industrially important compounds, such as 2- arylpropionic acids, which are non-steroidal anti-inflammatory drugs. Thus, the ability of the above-mentioned strains to hydrolyze these substrates was investigated, with the view to utilizing the maximum potential of these biocatalysts. The compounds used as substrates in the investigation are all essentially amides. Thus, the ability of the strains to hydrolyze imides, hydantoins, and amides, was investigated. In particular, imides have a structure which is very similar to that of hydantoins, and thus it was an objective of the study to determine whether these strains could hydrolyze imides. Imidehydrolyzing activity has only recently been discovered in microorganisms. Hydantoin conversion involves a two-step hydrolysis reaction which yields, initially, an Ncarbamylamino acid intermediate, and subsequently, an "-amino acid. The hydantoinhydrolyzing enzymes of a Pseudomonas putida strain, RU-KM3S, were characterized in a crude extract preparation and reaction conditions for its biocatalytic application were optimized. The optimum conditions for conversion of 5-methylhydantoin were found to be 3 hours at 40°C, with conversion yields greater than 50% achieved. The enzymes of RU-KM3S demonstrated considerable stability, retaining 80% of their activity after incubation at 40°C for 3 hours. The activities of the enzymes were increased by the addition of a detergent to the extraction medium, suggesting that the enzymes might be membrane-bound. The results of the determination of the metal-dependence of the hydantoinase and N-carbamylase of RUKM3S suggested that these enzymes required metal ions for activity, with metal ions such as Mg²⁺, Mn²⁺, Zn²⁺, and Co²⁺ resulting in activation of the enzymes. However, Cu²⁺ and Fe²⁺ caused inactivation of these enzymes. The stereoselectivity of the enzymes was investigated, and the results suggested that the hydantoinase was non-selective, whereas the N-carbamylase was L-selective. The hydantoin substrate selectivity of RU-KM3S was compared to that of three other hydantoinase-producing bacteria, RU-KM1, RU-KM3L, and RU-OR. The four strains were able to hydrolyze all of the seven substrates tested. However, there was a difference in activity levels between crude extract preparations and whole cells, with crude extracts generally showing higher activity than whole cells, except in the case of RU-KM1. Some difference was also observed in the order of preference of substrates between whole cells and crude extracts. The preferred substrate for RU-KM1 whole cells was isopropylhydantoin, whereas the crude extract preparation preferentially hydrolyzed p-hydroxyphenylhydantoin. RU-KM3L whole cells achieved a higher conversion yield with isobutylhydantoin, whereas the crude extract achieved a higher yield with 5-t-butylhydantoin. RU-KM3S whole cells and crude extract preferentially hydrolyzed 5-n-butylhydantoin, although the yield was greater with the crude extract. The highest conversion yields were observed with RU-KM3S crude extract, with conversion yields of 71.6% and 100% for n-butylhydantoin and phydroxyphenylhydantoin, respectively.The ability of RU-KM1, RU-KM3L, and RU-KM3S to hydrolyze nitriles, initially to amides and subsequently to carboxylic acids, was investigated. These strains were demonstrated to be unable to utilize acrylonitrile, propionitrile and benzonitrile as nitrogen sources, but were able to hydrolyze acrylonitrile, propionitrile and acetonitrile, in resting cell reactions. Nitrile hydrolysis was demonstrated to be inducible in all three strains, and the enzyme system responsible for nitrile hydrolysis was proposed to be a nitrile hydratase-amidase system. Amidase activity in the four bacterial strains was investigated. The ability of RU-KM1, RUKM3L, RU-KM3S, and RU-OR to utilize amides as a nitrogen source was investigated, and the results showed that propionamide was a good nitrogen source for all four of the strains. Amide-hydrolyzing activity, by resting cells, was shown to be inducible by propionamide in all four strains. RU-KM3S demonstrated superior amide-hydrolyzing ability in that it hydrolyzed propionamide, acetamide, and acrylamide to a greater extent than the other strains. Resting cells of RU-KM1 and RU-OR were demonstrated to have the ability to hydrolyze the imide substrate, succinimide, and this imidase activity was found to be inducible. These strains were also able to utilize this imide as the sole source of nitrogen for growth, which is a novel finding, as to date, bacteria have only be reported to utilize imides as a carbon source. The identity of the enzyme system responsible for succinimide hydrolysis is not yet clear. In conclusion, the hydantoin-hydrolyzing enzymes of RU-KM3S have been shown to be possibly membrane associated, which is a novel finding that has also been proposed in three other hydantoinase-producing strains in our laboratory. This study has shown that the Ncarbamylase of RU-KM3S is L-stereoselective, which, to our knowledge, is the first report of an L-stereospecific N-carbamylase in a Pseudomonas putida. Publication of these findings is already in progress. This is the first report on the study of imide hydrolysis in either an Agrobacterium tumefaciens or a Pseudomonas sp., and publications reporting these results are in preparation.
- Full Text:
- Date Issued: 2000
- Authors: Skepu, Zoleka G
- Date: 2000
- Subjects: Amides , Hydrolysis , Hydantoin , Imides
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3911 , http://hdl.handle.net/10962/d1003970 , Amides , Hydrolysis , Hydantoin , Imides
- Description: This thesis describes a series of investigations into the amide bond-hydrolyzing activity of bacterial strains RU-KM1, RU-KM3L, RU-KM3S, and RU-OR, which were previously isolated for their ability to hydrolyze hydantoins to amino acids. The main aim of the study was to develop biotransformations with potential application in the production of enantiomerically pure amino acids and related compounds. Several compounds may be used as substrates by biocatalysts for the production of amino acids, such as hydantoins, amino nitriles, and amides. These compounds are not only important for amino acid production, but they may be used for production of other industrially important compounds, such as 2- arylpropionic acids, which are non-steroidal anti-inflammatory drugs. Thus, the ability of the above-mentioned strains to hydrolyze these substrates was investigated, with the view to utilizing the maximum potential of these biocatalysts. The compounds used as substrates in the investigation are all essentially amides. Thus, the ability of the strains to hydrolyze imides, hydantoins, and amides, was investigated. In particular, imides have a structure which is very similar to that of hydantoins, and thus it was an objective of the study to determine whether these strains could hydrolyze imides. Imidehydrolyzing activity has only recently been discovered in microorganisms. Hydantoin conversion involves a two-step hydrolysis reaction which yields, initially, an Ncarbamylamino acid intermediate, and subsequently, an "-amino acid. The hydantoinhydrolyzing enzymes of a Pseudomonas putida strain, RU-KM3S, were characterized in a crude extract preparation and reaction conditions for its biocatalytic application were optimized. The optimum conditions for conversion of 5-methylhydantoin were found to be 3 hours at 40°C, with conversion yields greater than 50% achieved. The enzymes of RU-KM3S demonstrated considerable stability, retaining 80% of their activity after incubation at 40°C for 3 hours. The activities of the enzymes were increased by the addition of a detergent to the extraction medium, suggesting that the enzymes might be membrane-bound. The results of the determination of the metal-dependence of the hydantoinase and N-carbamylase of RUKM3S suggested that these enzymes required metal ions for activity, with metal ions such as Mg²⁺, Mn²⁺, Zn²⁺, and Co²⁺ resulting in activation of the enzymes. However, Cu²⁺ and Fe²⁺ caused inactivation of these enzymes. The stereoselectivity of the enzymes was investigated, and the results suggested that the hydantoinase was non-selective, whereas the N-carbamylase was L-selective. The hydantoin substrate selectivity of RU-KM3S was compared to that of three other hydantoinase-producing bacteria, RU-KM1, RU-KM3L, and RU-OR. The four strains were able to hydrolyze all of the seven substrates tested. However, there was a difference in activity levels between crude extract preparations and whole cells, with crude extracts generally showing higher activity than whole cells, except in the case of RU-KM1. Some difference was also observed in the order of preference of substrates between whole cells and crude extracts. The preferred substrate for RU-KM1 whole cells was isopropylhydantoin, whereas the crude extract preparation preferentially hydrolyzed p-hydroxyphenylhydantoin. RU-KM3L whole cells achieved a higher conversion yield with isobutylhydantoin, whereas the crude extract achieved a higher yield with 5-t-butylhydantoin. RU-KM3S whole cells and crude extract preferentially hydrolyzed 5-n-butylhydantoin, although the yield was greater with the crude extract. The highest conversion yields were observed with RU-KM3S crude extract, with conversion yields of 71.6% and 100% for n-butylhydantoin and phydroxyphenylhydantoin, respectively.The ability of RU-KM1, RU-KM3L, and RU-KM3S to hydrolyze nitriles, initially to amides and subsequently to carboxylic acids, was investigated. These strains were demonstrated to be unable to utilize acrylonitrile, propionitrile and benzonitrile as nitrogen sources, but were able to hydrolyze acrylonitrile, propionitrile and acetonitrile, in resting cell reactions. Nitrile hydrolysis was demonstrated to be inducible in all three strains, and the enzyme system responsible for nitrile hydrolysis was proposed to be a nitrile hydratase-amidase system. Amidase activity in the four bacterial strains was investigated. The ability of RU-KM1, RUKM3L, RU-KM3S, and RU-OR to utilize amides as a nitrogen source was investigated, and the results showed that propionamide was a good nitrogen source for all four of the strains. Amide-hydrolyzing activity, by resting cells, was shown to be inducible by propionamide in all four strains. RU-KM3S demonstrated superior amide-hydrolyzing ability in that it hydrolyzed propionamide, acetamide, and acrylamide to a greater extent than the other strains. Resting cells of RU-KM1 and RU-OR were demonstrated to have the ability to hydrolyze the imide substrate, succinimide, and this imidase activity was found to be inducible. These strains were also able to utilize this imide as the sole source of nitrogen for growth, which is a novel finding, as to date, bacteria have only be reported to utilize imides as a carbon source. The identity of the enzyme system responsible for succinimide hydrolysis is not yet clear. In conclusion, the hydantoin-hydrolyzing enzymes of RU-KM3S have been shown to be possibly membrane associated, which is a novel finding that has also been proposed in three other hydantoinase-producing strains in our laboratory. This study has shown that the Ncarbamylase of RU-KM3S is L-stereoselective, which, to our knowledge, is the first report of an L-stereospecific N-carbamylase in a Pseudomonas putida. Publication of these findings is already in progress. This is the first report on the study of imide hydrolysis in either an Agrobacterium tumefaciens or a Pseudomonas sp., and publications reporting these results are in preparation.
- Full Text:
- Date Issued: 2000
Rhodes University Graduation Ceremony 2000
- Authors: Rhodes University
- Date: 2000
- Language: English
- Type: text
- Identifier: vital:8147 , http://hdl.handle.net/10962/d1007297
- Description: Rhodes University Graduation Ceremony [at] 1820 Settlers National Monument Friday, 7 April 2000 at 10:30; 18:00 [and] Saturday, 8 April 2000 at 10:30 , Graduation Ceremony Guild Theatre, Oxford Street, East London Friday, 19 May 2000 at 18:00 [and] Saturday, 20 May 2000 at 14:30
- Full Text:
- Date Issued: 2000
- Authors: Rhodes University
- Date: 2000
- Language: English
- Type: text
- Identifier: vital:8147 , http://hdl.handle.net/10962/d1007297
- Description: Rhodes University Graduation Ceremony [at] 1820 Settlers National Monument Friday, 7 April 2000 at 10:30; 18:00 [and] Saturday, 8 April 2000 at 10:30 , Graduation Ceremony Guild Theatre, Oxford Street, East London Friday, 19 May 2000 at 18:00 [and] Saturday, 20 May 2000 at 14:30
- Full Text:
- Date Issued: 2000
The experience of multi-cultural communication within a South African organization
- Authors: Lesch, Anthea M
- Date: 2000
- Subjects: Intercultural communication -- South Africa , Communication in management -- South Africa , Communication in personnel management -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:3008 , http://hdl.handle.net/10962/d1002517 , Intercultural communication -- South Africa , Communication in management -- South Africa , Communication in personnel management -- South Africa
- Description: This research study was conducted in an attempt to explore the experience of multicultural communication within a South African organization. To this end employees, representing both Black and White culture, within a South African organization in the throes of transformation, were accessed. A model of managing diversity, focussing on the personal, interpersonal and organizational levels, was utilized in an attempt to uncover the nature of the experience of multi-cultural communication within Company X. A qualitative research design, and more specifically the case study method was employed in this study. Consistent with the case study approach a number of data sources were accessed. The primary data source consisted of a 3-stage interview process. Other data sources included documentary sources and company publications. By accessing multiple data sources, the researcher attempted to gain a holistic understanding of the experience of multi-cultural communication. It was found that the societal context of our post-Apartheid society exercises a profound influence on multi-cultural communication. Under Apartheid cultural separation was promoted. Diverse peoples thus have little common basis for interaction and view each other with skepticism and distrust. This exercises an effect on the personal and organizational levels of the managing diversity model. Influences at the personal level relate to the cultural paradigms of the individuals which provide the rules governing interactions and affect judgements of acceptable and unacceptable behaviours. Issues at the organizational level relate to its structures and policies which are still based on the “white is right ideology”. These issues, in turn, affect the interpersonal level of managing diversity, i.e., where the interactions occur, causing “communication short circuits” within the process of multi-cultural communication. In order to deal with failed multi-cultural communication, the individuals have developed a number of coping strategies. The results of the study indicate that both the organization and its employees share a responsibility for creating an environment that will facilitate effective multi-cultural communication.
- Full Text:
- Date Issued: 2000
- Authors: Lesch, Anthea M
- Date: 2000
- Subjects: Intercultural communication -- South Africa , Communication in management -- South Africa , Communication in personnel management -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:3008 , http://hdl.handle.net/10962/d1002517 , Intercultural communication -- South Africa , Communication in management -- South Africa , Communication in personnel management -- South Africa
- Description: This research study was conducted in an attempt to explore the experience of multicultural communication within a South African organization. To this end employees, representing both Black and White culture, within a South African organization in the throes of transformation, were accessed. A model of managing diversity, focussing on the personal, interpersonal and organizational levels, was utilized in an attempt to uncover the nature of the experience of multi-cultural communication within Company X. A qualitative research design, and more specifically the case study method was employed in this study. Consistent with the case study approach a number of data sources were accessed. The primary data source consisted of a 3-stage interview process. Other data sources included documentary sources and company publications. By accessing multiple data sources, the researcher attempted to gain a holistic understanding of the experience of multi-cultural communication. It was found that the societal context of our post-Apartheid society exercises a profound influence on multi-cultural communication. Under Apartheid cultural separation was promoted. Diverse peoples thus have little common basis for interaction and view each other with skepticism and distrust. This exercises an effect on the personal and organizational levels of the managing diversity model. Influences at the personal level relate to the cultural paradigms of the individuals which provide the rules governing interactions and affect judgements of acceptable and unacceptable behaviours. Issues at the organizational level relate to its structures and policies which are still based on the “white is right ideology”. These issues, in turn, affect the interpersonal level of managing diversity, i.e., where the interactions occur, causing “communication short circuits” within the process of multi-cultural communication. In order to deal with failed multi-cultural communication, the individuals have developed a number of coping strategies. The results of the study indicate that both the organization and its employees share a responsibility for creating an environment that will facilitate effective multi-cultural communication.
- Full Text:
- Date Issued: 2000
Portfolio of three projects
- Authors: Thomas, Lorraine
- Date: 2000
- Subjects: Educational leadership Organizational change Educational change School management and organization -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1707 , http://hdl.handle.net/10962/d1003590
- Description: Educational leadership and management is a very wide field of study with interdependent components that should form a chain reaction in order to bring about effective management. This study attempts to investigate planning in schools which is one of the educational leadership and management components or functions. Very little research work has been done on educational planning in the Ciskei schools. This is a shortcoming since the number of secondary schools has mushroomed in the late twentieth century. The Ciskei educational managers and parents need to know and take note of the possible situations in the various schools. This is opportune time, particularly that recent events, i.e. students' demands and strikes, are drawing parents closer to the education of their children. The researcher's experience of inspecting school administration since 1990 has reinforced his conviction that the managerial teams in the Ciskei secondary schools have little knowledge of management, and of planning in particular. Although the investigation is into secondary school administration, it is also pertinent to primary school planning. Management, i.e. school year-planning, control of work, staff development, appointment of teachers, policy governing students and teachers are discussed at length . Joint planning, i.e. a participative or consultative approach, and advance planning, are investigated in relation to the school year-programme. The existence of statutory bodies in the various schools is assessed in order to test parents' involvement in the education of their children. School tours are discussed in relation to students' involvement in the school activities. The analysis of the results highlights areas that require attention, and the recommendations given address the controversial issues in planning in the various schools.
- Full Text:
- Date Issued: 2000
- Authors: Thomas, Lorraine
- Date: 2000
- Subjects: Educational leadership Organizational change Educational change School management and organization -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1707 , http://hdl.handle.net/10962/d1003590
- Description: Educational leadership and management is a very wide field of study with interdependent components that should form a chain reaction in order to bring about effective management. This study attempts to investigate planning in schools which is one of the educational leadership and management components or functions. Very little research work has been done on educational planning in the Ciskei schools. This is a shortcoming since the number of secondary schools has mushroomed in the late twentieth century. The Ciskei educational managers and parents need to know and take note of the possible situations in the various schools. This is opportune time, particularly that recent events, i.e. students' demands and strikes, are drawing parents closer to the education of their children. The researcher's experience of inspecting school administration since 1990 has reinforced his conviction that the managerial teams in the Ciskei secondary schools have little knowledge of management, and of planning in particular. Although the investigation is into secondary school administration, it is also pertinent to primary school planning. Management, i.e. school year-planning, control of work, staff development, appointment of teachers, policy governing students and teachers are discussed at length . Joint planning, i.e. a participative or consultative approach, and advance planning, are investigated in relation to the school year-programme. The existence of statutory bodies in the various schools is assessed in order to test parents' involvement in the education of their children. School tours are discussed in relation to students' involvement in the school activities. The analysis of the results highlights areas that require attention, and the recommendations given address the controversial issues in planning in the various schools.
- Full Text:
- Date Issued: 2000
Ethnic nationalism and democratisation in South Africa : political implications for the rainbow nation
- Authors: Naidoo, Vinothan
- Date: 2000
- Subjects: Nationalism -- South Africa , Ethnicity -- South Africa , Democracy -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2815 , http://hdl.handle.net/10962/d1003025 , Nationalism -- South Africa , Ethnicity -- South Africa , Democracy -- South Africa , South Africa -- Politics and government -- 1994-
- Description: Ethnic identities in South Africa have had a particularly contrived history, set within the constraints and motivations of population classification by race. A more democratic political environment emerged with the dismantling of apartheid, bringing with it a multitude of issues including the design and character of the country’s political institutions and framework. This thesis will address two principal questions. The first and primary one investigates what lies behind the initiation and development of ethnic bonds. The second concerns the political implications and management of ethnic expressions in a democratic South Africa. An analysis of Zulu ethnic nationalism will be undertaken, because it constituted the most prominent case of assertive communal interests during democratic transitional negotiations. This thesis argues that circumstantial and instrumental factors (based on conditions, and the actions of individuals and organizations respectively), have been predominately responsible for the initiation and formation of ethnic bonds, especially amongst those who identify with a Zulu identity. The “conditions” describe the increasingly segregationist direction in which successive South African government authorities were moving, especially after the 1948 election victory of the National Party and the subsequent introduction of apartheid. Secondly, the “actions” denote the motivations of both Zulu actors and governments in generating and elaborating an ethnic discourse where their desired interests could be more effectively supported and assured. It will also be argued that because of the instrumental and selective use of ethnicity, as well as the narrow interests being served by its popular and community-centred expressions, a developing South African democratic culture should seek to protect ethnic diversity rather than promote ethnic interests. To do so would be to deny the perpetuation of ethnic cleavages and the violence and instability perpetrated in its name in recent years. The “protection” of cultural diversity is consistent with a constitution that seeks non-discrimination among all South African identities. Finally, it is believed that an emphasis on the individual as individual, as well as member of a cultural group, will break from subordinating the individual to an ascribed racial and ethnic identity as in the past, and assist in reconstituting the state as equally reflective of all South Africans.
- Full Text:
- Date Issued: 2000
- Authors: Naidoo, Vinothan
- Date: 2000
- Subjects: Nationalism -- South Africa , Ethnicity -- South Africa , Democracy -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2815 , http://hdl.handle.net/10962/d1003025 , Nationalism -- South Africa , Ethnicity -- South Africa , Democracy -- South Africa , South Africa -- Politics and government -- 1994-
- Description: Ethnic identities in South Africa have had a particularly contrived history, set within the constraints and motivations of population classification by race. A more democratic political environment emerged with the dismantling of apartheid, bringing with it a multitude of issues including the design and character of the country’s political institutions and framework. This thesis will address two principal questions. The first and primary one investigates what lies behind the initiation and development of ethnic bonds. The second concerns the political implications and management of ethnic expressions in a democratic South Africa. An analysis of Zulu ethnic nationalism will be undertaken, because it constituted the most prominent case of assertive communal interests during democratic transitional negotiations. This thesis argues that circumstantial and instrumental factors (based on conditions, and the actions of individuals and organizations respectively), have been predominately responsible for the initiation and formation of ethnic bonds, especially amongst those who identify with a Zulu identity. The “conditions” describe the increasingly segregationist direction in which successive South African government authorities were moving, especially after the 1948 election victory of the National Party and the subsequent introduction of apartheid. Secondly, the “actions” denote the motivations of both Zulu actors and governments in generating and elaborating an ethnic discourse where their desired interests could be more effectively supported and assured. It will also be argued that because of the instrumental and selective use of ethnicity, as well as the narrow interests being served by its popular and community-centred expressions, a developing South African democratic culture should seek to protect ethnic diversity rather than promote ethnic interests. To do so would be to deny the perpetuation of ethnic cleavages and the violence and instability perpetrated in its name in recent years. The “protection” of cultural diversity is consistent with a constitution that seeks non-discrimination among all South African identities. Finally, it is believed that an emphasis on the individual as individual, as well as member of a cultural group, will break from subordinating the individual to an ascribed racial and ethnic identity as in the past, and assist in reconstituting the state as equally reflective of all South Africans.
- Full Text:
- Date Issued: 2000
A portfolio of original compositions with a commentary
- Authors: Nkuna, Musa
- Date: 2000
- Subjects: String quartets -- Scores Song cycles -- Scores Music -- Africa -- Scores
- Language: English
- Type: text , Thesis , Masters , MMus
- Identifier: vital:2698 , http://hdl.handle.net/10962/d1018689
- Description: This portfolio consists of four diverse original compositions written in 1999 : a string quartet, a cello suite and a set of two choral pieces.
- Full Text:
- Date Issued: 2000
- Authors: Nkuna, Musa
- Date: 2000
- Subjects: String quartets -- Scores Song cycles -- Scores Music -- Africa -- Scores
- Language: English
- Type: text , Thesis , Masters , MMus
- Identifier: vital:2698 , http://hdl.handle.net/10962/d1018689
- Description: This portfolio consists of four diverse original compositions written in 1999 : a string quartet, a cello suite and a set of two choral pieces.
- Full Text:
- Date Issued: 2000
Physiological, perceptual and other performance decrements in combat related tasks following prolonged heavy-load marching
- Authors: Clark, Lisa Anne
- Date: 2000
- Subjects: Performance -- Psychological aspects , Performance standards -- Case studies , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Marching -- Physiological aspects , Soldiers -- Job stress
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5130 , http://hdl.handle.net/10962/d1005209 , Performance -- Psychological aspects , Performance standards -- Case studies , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Marching -- Physiological aspects , Soldiers -- Job stress
- Description: In response to challenging situations physiological and psychological adaptations result in elevated levels of arousal and when these levels are 'optimal' performance is enhanced. There are however, limitations to the amount of physiological and mental stimulation one can tolerate, with cumulative fatigue effects being the outcome when stressful conditions are imposed on the individual over an extended period of time. As a result of the extreme physical and cognitive demands placed on military forces while in combat, with soldiers being thrust into battle and required to make critical life-or-death determining decisions followed by appropriate motor responses, the physical and psychological capabilities of the troops are pushed to maximal limits, often resulting in undesirable decrements in physical and mental performance, with consequential human and materiel losses. Thirty-two soldiers participated in a battery of combat-related field and laboratory tests, first under 'normal' conditions with no prior physical activity and then immediately after the participation of an intensive bout of exercise. Physiological and perceptual responses plus standard of performance were measured at various stages of testing. Results of the Rating of Perceived Exertion (RPE), Body Discomfort Scale and heart rate responses revealed significantly higher levels of psychophysical strai,n in response to the strenuous physical activity. Despite these findings, the electromyographic (EMG) activity and efficiency of the combat-related skills were not negatively affected. Rather, nominal improvements in post-activity performance were noted, specifically response time, and this was attributed to elevated arousal and activation as a result of the exercise that was of sufficient duration to enhance arousal without imposing long term cumulative fatigue effects.
- Full Text:
- Date Issued: 2000
- Authors: Clark, Lisa Anne
- Date: 2000
- Subjects: Performance -- Psychological aspects , Performance standards -- Case studies , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Marching -- Physiological aspects , Soldiers -- Job stress
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5130 , http://hdl.handle.net/10962/d1005209 , Performance -- Psychological aspects , Performance standards -- Case studies , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Marching -- Physiological aspects , Soldiers -- Job stress
- Description: In response to challenging situations physiological and psychological adaptations result in elevated levels of arousal and when these levels are 'optimal' performance is enhanced. There are however, limitations to the amount of physiological and mental stimulation one can tolerate, with cumulative fatigue effects being the outcome when stressful conditions are imposed on the individual over an extended period of time. As a result of the extreme physical and cognitive demands placed on military forces while in combat, with soldiers being thrust into battle and required to make critical life-or-death determining decisions followed by appropriate motor responses, the physical and psychological capabilities of the troops are pushed to maximal limits, often resulting in undesirable decrements in physical and mental performance, with consequential human and materiel losses. Thirty-two soldiers participated in a battery of combat-related field and laboratory tests, first under 'normal' conditions with no prior physical activity and then immediately after the participation of an intensive bout of exercise. Physiological and perceptual responses plus standard of performance were measured at various stages of testing. Results of the Rating of Perceived Exertion (RPE), Body Discomfort Scale and heart rate responses revealed significantly higher levels of psychophysical strai,n in response to the strenuous physical activity. Despite these findings, the electromyographic (EMG) activity and efficiency of the combat-related skills were not negatively affected. Rather, nominal improvements in post-activity performance were noted, specifically response time, and this was attributed to elevated arousal and activation as a result of the exercise that was of sufficient duration to enhance arousal without imposing long term cumulative fatigue effects.
- Full Text:
- Date Issued: 2000
A case study of multigrade teaching in Canada: implications for South Africa
- Authors: Muthayan, Saloshini
- Date: 2000
- Subjects: Combination of grades -- South Africa Combination of grades -- Canada Education, Elementary -- South Africa Education, Elementary -- Canada Combination of grades
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1438 , http://hdl.handle.net/10962/d1003319
- Description: This study examines multigrade teaching in selected schools in Canada and its implications for improving multigrade teaching in South Africa, where over 50 % of primary schools are multigrade and the teachers have not received preparation in multigrade teaching. The case study method was adopted because it allowed for 'an intensive, holistic description and analysis' of the multigrade classroom. The approach is interpretivist, based on the assumption that social phenomena are 'socially constituted' and 'valuationally based'. Research techniques included a literature review, interviews and observations. Four classrooms with grade combinations ranging from two grades to eight grades (Kindergarten to grade 7) were studied. Despite problems such as the lack of official recognition, inadequate teacher education and support - problems common to both Canada and South Africa - the Canadian teachers managed their classrooms effectively. This was indicated by their understanding of the children's needs, their integration of the curriculum for teaching across the grades and the learning areas, their use of effective instructional strategies and their involyement of parents in the classroom. A reason for their success may be that their teacher education includes child-centred, activity based approaches, integration of the curriculum, critical thinking, flexibility and effective instructional strategies, which they may adapt for effective multigrade teaching. The study found that successful multigrade teaching depended on the teacher. For South Africa, this may imply that intervention programmes should focus on relevant preparation and support for multigrade teachers. The emphasis on material resources in the implementation of Curriculum 2005 has not been balanced with adequate training on policy, curriculum and instructional strategies. Teacher education should include methodologies that are experiential, reflective and participatory. A variety of instructional strategies should be employed in the multigrade classroom. The respondents in the study believed further that multigrade teaching is more beneficial than single-grade teaching because it caters for the diversity of needs amongst children and allows for peer tutoring, thereby exploiting Vygotsky's theory of the 'zone of proximal development'. Thus, instead of viewing multigrade teaching as a temporary phenomenon, it should be viewed as an opportunity for improving school effectiveness.
- Full Text:
- Date Issued: 2000
- Authors: Muthayan, Saloshini
- Date: 2000
- Subjects: Combination of grades -- South Africa Combination of grades -- Canada Education, Elementary -- South Africa Education, Elementary -- Canada Combination of grades
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1438 , http://hdl.handle.net/10962/d1003319
- Description: This study examines multigrade teaching in selected schools in Canada and its implications for improving multigrade teaching in South Africa, where over 50 % of primary schools are multigrade and the teachers have not received preparation in multigrade teaching. The case study method was adopted because it allowed for 'an intensive, holistic description and analysis' of the multigrade classroom. The approach is interpretivist, based on the assumption that social phenomena are 'socially constituted' and 'valuationally based'. Research techniques included a literature review, interviews and observations. Four classrooms with grade combinations ranging from two grades to eight grades (Kindergarten to grade 7) were studied. Despite problems such as the lack of official recognition, inadequate teacher education and support - problems common to both Canada and South Africa - the Canadian teachers managed their classrooms effectively. This was indicated by their understanding of the children's needs, their integration of the curriculum for teaching across the grades and the learning areas, their use of effective instructional strategies and their involyement of parents in the classroom. A reason for their success may be that their teacher education includes child-centred, activity based approaches, integration of the curriculum, critical thinking, flexibility and effective instructional strategies, which they may adapt for effective multigrade teaching. The study found that successful multigrade teaching depended on the teacher. For South Africa, this may imply that intervention programmes should focus on relevant preparation and support for multigrade teachers. The emphasis on material resources in the implementation of Curriculum 2005 has not been balanced with adequate training on policy, curriculum and instructional strategies. Teacher education should include methodologies that are experiential, reflective and participatory. A variety of instructional strategies should be employed in the multigrade classroom. The respondents in the study believed further that multigrade teaching is more beneficial than single-grade teaching because it caters for the diversity of needs amongst children and allows for peer tutoring, thereby exploiting Vygotsky's theory of the 'zone of proximal development'. Thus, instead of viewing multigrade teaching as a temporary phenomenon, it should be viewed as an opportunity for improving school effectiveness.
- Full Text:
- Date Issued: 2000
Photocatalytic reactions of metal diphthalocyanine complexes
- Authors: Nensala, Ngudiankama
- Date: 2000
- Subjects: Metal complexes Electrochemistry Photochemistry Pentachlorophenol
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4328 , http://hdl.handle.net/10962/d1004989
- Description: Photocatalytic reactions of tin diphthalocyanine, Sn ^IVPc₂ and anionic form of Nd^III, Dy^III, Eu^III, Tm^III and Lu^III diphthalocyanine complexes ( [Pc(-2)Nd^IIIpc(-2)]⁻ , [Pc(-2)Dy^IIIPc(-2)]⁻ , [Pc(-2)Eu^IIIPc(-2)⁻, [Pc(-2)Tm^IIlPc(-2)r and [Pc(-2)LuIIIpc(-2)]⁻ respectively) in the presence of CH₂CI₂, S0₂, pentachlorophenol (PCP), 4-chlorophenol (4-Cp) and thionyl chloride have been studied. Photoreactions involving lanthanide diphthalocyanines, filtered and unfiltered radiations were employed, whereas for photoreactions involving tin diphthalocyanine, only unfiltered radiation was employed. For lanthanide diphthalocyanine complexes, LnPce-, the photosensitization power increases with the decrease of the lanthanide ionic radii, implying that the photocatalytic activity of LnPc₂⁻ complexes is associated with the π-π interaction between both phthalocyanine rings. Thus, LuPc₂⁻ is a better photocatalyst than other lanthanide diphthalocyanine complexes. Photolysis ofSnPc₂ in an acetonitrile/dichloromethane solvent mixture, using unfiltered radiation from a tungsten lamp, results in the one-electron oxidation of this species to [Pc( -2 )Sn(IV)Pc(-1)]⁻. The relative quantum yields for the disappearance of SnPc₂ are in the order of 10⁻¹. The photoreaction of SnPc₂ is preceded by excitation to nπ* excited states, before been ,quenched by CH₂CI₂. The one-electron oxidation species, [Pc(-2)Sn(lV)pc(-1)]⁻ was also formed during the photolysis of SnPc₂ in dichloromethane containing S0₂, and with quantum yields of order of 10⁻³. Visible photolysis of [Pc( -2)Nd^IIIpc(-2)]⁻, [Pc(-2)Dy^IIIPc(-2)]⁻ and [Pc(-2)Lu^IIIpc(-2)]⁻ in N,N. dimethylformamide (DMF)/dichloromethane solvent mixture containing SO₂, results in the formation of the one-electron oxidation species, Pc(-2 )Nd^IIIpc(-1), Pc( -2) Dyi^IIIPc(-1) and Pc(-2)Lu^IIIpc(-1), respectively. The relative quantum yields are in the order of 10². The photoreactions are preceded by population of the excited triplet state,³π-π* [ LnPc₂]⁻ complex, before exchanging an electron with S0₂. The one-electron oxidation species of Dy^III and Lu^III diphthalocyanine complexes have also been formed from visible photolysis of [Pc(-2 )Dy^IIIPc(-2)]⁻and [Pc(-2)Lu^IIIpc(-2)]⁻in acetonitrile containing PCP. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are in the order of 1 0⁻. Photolysis, using visible radiation from 220 W Quartzline lamp, of an aqueous solution of 4-Cp, saturated with oxygen and containing a suspension of solid [Pc(-2)Nd^IIIpc(-2)]⁻, results in the formation of benzoquinone, hydro quinone and 4-chlorocatechol. The quantum yields for the degradation of 4-Cp are in the order of 10⁻. Langmuir-Hinshelwood kinetic model shows the adsorption of 4-chlorophenol onto solid [Pc(-2)Nd^IIIpc(-2)]⁻. Lanthanide diphthalocyanine complexes ([Pc-2)Nd^IIIpc(-2)]⁻. [Pc(-2)Eu^IIIpc(-2)]⁻, (Pc(-2)Tm^IIIpc( -2)]⁻ and (Pc(-2)Lu^IIIpc(-2)]⁻) undergo one or two-electron oxidation in the presence of thionyl chloride. At low concentrations of SOCI₂(<10⁻⁴ mol dm⁻³) the visible yhotolysis of [Pc(-2 )LnPc(-2)]⁻ complexes result in the one-electron oxidation, giving neutral lanthanide diphthalocyanine species, Pc(-2)Ln^IIIpc(-1). The Pc(-2 )LnPc(-I) species undergoes one-electron photooxidation to [Pc(-I )LnPc( -I)]⁻ in dichloromethane and in the presence of SOC₁₂. At large concentrations of SOC₁₂ (>10⁻² mol dm⁻³), direct two-electron oxidation of the (Pc(-2 )LnPc - 2)]⁻ species to (Pc(-1)LnPc(-1)]⁻ occurs. Spectroelectrochemical behaviours of Sn^IVPc₂ have been also studied. The cyclic voltammetry ofSnPc₂ in CH₂CI₂/TBAP show two reduction couples at -0.56 V and -0.89 V versus saturated calomel electrode (SCE) and one oxidation couple at 0.35 V versus SCE. In DMFITEAP system, the reduction couples are observed at -0.44 V and -0.81 V versus SCE whereas the oxidation couple occurred at 0.43 V versus SCE. The oxidation couple corresponds to [Pc(-2 )Sn^IVPc(-2 )]/[Pc(-2)Sn^IVPc( -I)] . and the reduction couples to [Pc(-2)Sn^IVPc( -2 )]/[Pc(-2 )Sn^IVPc( -3 )]⁻ and [Pc(-2)Snl^IVPc( -3)] ⁻/[Pc(-3 )Sn^IVPc(-3)]²⁻, respectively. The electronic absorption spectra of these reduced and oxidized species are reported.
- Full Text:
- Date Issued: 2000
- Authors: Nensala, Ngudiankama
- Date: 2000
- Subjects: Metal complexes Electrochemistry Photochemistry Pentachlorophenol
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4328 , http://hdl.handle.net/10962/d1004989
- Description: Photocatalytic reactions of tin diphthalocyanine, Sn ^IVPc₂ and anionic form of Nd^III, Dy^III, Eu^III, Tm^III and Lu^III diphthalocyanine complexes ( [Pc(-2)Nd^IIIpc(-2)]⁻ , [Pc(-2)Dy^IIIPc(-2)]⁻ , [Pc(-2)Eu^IIIPc(-2)⁻, [Pc(-2)Tm^IIlPc(-2)r and [Pc(-2)LuIIIpc(-2)]⁻ respectively) in the presence of CH₂CI₂, S0₂, pentachlorophenol (PCP), 4-chlorophenol (4-Cp) and thionyl chloride have been studied. Photoreactions involving lanthanide diphthalocyanines, filtered and unfiltered radiations were employed, whereas for photoreactions involving tin diphthalocyanine, only unfiltered radiation was employed. For lanthanide diphthalocyanine complexes, LnPce-, the photosensitization power increases with the decrease of the lanthanide ionic radii, implying that the photocatalytic activity of LnPc₂⁻ complexes is associated with the π-π interaction between both phthalocyanine rings. Thus, LuPc₂⁻ is a better photocatalyst than other lanthanide diphthalocyanine complexes. Photolysis ofSnPc₂ in an acetonitrile/dichloromethane solvent mixture, using unfiltered radiation from a tungsten lamp, results in the one-electron oxidation of this species to [Pc( -2 )Sn(IV)Pc(-1)]⁻. The relative quantum yields for the disappearance of SnPc₂ are in the order of 10⁻¹. The photoreaction of SnPc₂ is preceded by excitation to nπ* excited states, before been ,quenched by CH₂CI₂. The one-electron oxidation species, [Pc(-2)Sn(lV)pc(-1)]⁻ was also formed during the photolysis of SnPc₂ in dichloromethane containing S0₂, and with quantum yields of order of 10⁻³. Visible photolysis of [Pc( -2)Nd^IIIpc(-2)]⁻, [Pc(-2)Dy^IIIPc(-2)]⁻ and [Pc(-2)Lu^IIIpc(-2)]⁻ in N,N. dimethylformamide (DMF)/dichloromethane solvent mixture containing SO₂, results in the formation of the one-electron oxidation species, Pc(-2 )Nd^IIIpc(-1), Pc( -2) Dyi^IIIPc(-1) and Pc(-2)Lu^IIIpc(-1), respectively. The relative quantum yields are in the order of 10². The photoreactions are preceded by population of the excited triplet state,³π-π* [ LnPc₂]⁻ complex, before exchanging an electron with S0₂. The one-electron oxidation species of Dy^III and Lu^III diphthalocyanine complexes have also been formed from visible photolysis of [Pc(-2 )Dy^IIIPc(-2)]⁻and [Pc(-2)Lu^IIIpc(-2)]⁻in acetonitrile containing PCP. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are in the order of 1 0⁻. Photolysis, using visible radiation from 220 W Quartzline lamp, of an aqueous solution of 4-Cp, saturated with oxygen and containing a suspension of solid [Pc(-2)Nd^IIIpc(-2)]⁻, results in the formation of benzoquinone, hydro quinone and 4-chlorocatechol. The quantum yields for the degradation of 4-Cp are in the order of 10⁻. Langmuir-Hinshelwood kinetic model shows the adsorption of 4-chlorophenol onto solid [Pc(-2)Nd^IIIpc(-2)]⁻. Lanthanide diphthalocyanine complexes ([Pc-2)Nd^IIIpc(-2)]⁻. [Pc(-2)Eu^IIIpc(-2)]⁻, (Pc(-2)Tm^IIIpc( -2)]⁻ and (Pc(-2)Lu^IIIpc(-2)]⁻) undergo one or two-electron oxidation in the presence of thionyl chloride. At low concentrations of SOCI₂(<10⁻⁴ mol dm⁻³) the visible yhotolysis of [Pc(-2 )LnPc(-2)]⁻ complexes result in the one-electron oxidation, giving neutral lanthanide diphthalocyanine species, Pc(-2)Ln^IIIpc(-1). The Pc(-2 )LnPc(-I) species undergoes one-electron photooxidation to [Pc(-I )LnPc( -I)]⁻ in dichloromethane and in the presence of SOC₁₂. At large concentrations of SOC₁₂ (>10⁻² mol dm⁻³), direct two-electron oxidation of the (Pc(-2 )LnPc - 2)]⁻ species to (Pc(-1)LnPc(-1)]⁻ occurs. Spectroelectrochemical behaviours of Sn^IVPc₂ have been also studied. The cyclic voltammetry ofSnPc₂ in CH₂CI₂/TBAP show two reduction couples at -0.56 V and -0.89 V versus saturated calomel electrode (SCE) and one oxidation couple at 0.35 V versus SCE. In DMFITEAP system, the reduction couples are observed at -0.44 V and -0.81 V versus SCE whereas the oxidation couple occurred at 0.43 V versus SCE. The oxidation couple corresponds to [Pc(-2 )Sn^IVPc(-2 )]/[Pc(-2)Sn^IVPc( -I)] . and the reduction couples to [Pc(-2)Sn^IVPc( -2 )]/[Pc(-2 )Sn^IVPc( -3 )]⁻ and [Pc(-2)Snl^IVPc( -3)] ⁻/[Pc(-3 )Sn^IVPc(-3)]²⁻, respectively. The electronic absorption spectra of these reduced and oxidized species are reported.
- Full Text:
- Date Issued: 2000
Ammonia removal from water by ion exchange using South African and Zambian zeolite samples
- Authors: Mwale, Monica
- Date: 2000
- Subjects: Ammonia -- Toxicology , Water -- Purification , Zeolites , Ion exchange
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5215 , http://hdl.handle.net/10962/d1005058 , Ammonia -- Toxicology , Water -- Purification , Zeolites , Ion exchange
- Description: One problem of intensive fish culture systems is the progressive build-up of toxic wastes such as ammonia. The possibility of improving aquaculture water quality using two kinds of zeolite is discussed. Zeolites are alumino-silicates whose framework allows them to exchange cations. Ion exchange has been demonstrated to be competitive with other methods of ammonia removal due to the high selectivity for ammonia exhibited by zeolite materials. In this study an unknown Zambian zeolite (identified as laumontite by X-ray diffraction techniques) and Pratley clinoptilolite (a South African zeolite) were tested under laboratory conditions and in a fresh water recirculating system. Ammonia cation exchange capacities (CEC) and suitable application rates for efficient water treatment were determined using the batch and column ion exchange procedures. Estimated ammonia uptake, the most important criterion used to assess performance of zeolite filters was strongly influenced by zeolite type, particle size, pre-treatment, regeneration and ion exchange method used. Statistical analysis showed significant differences in average ammonia CEC values between clinoptilolite (14.94 mg g⁻¹) and laumontite (2.77 mg g⁻¹), with the former displaying a higher Na⁺ ® NH₄⁺ exchange rate especially in the early reaction stages. This difference accords with the higher purity of clinoptilolite, 47% as opposed to 4.7% for laumontite, which makes it a better zeolite for ammonium removal. CEC increased linearly as particle size of the clinoptilolite was reduced resulting in a linear regression model (y = 18.29 – 3.704 x; r² = 74%). Pre-treatment of clinoptilolite using 1N NaCl significantly improved the ammonia CEC of clinoptilolite. Overall performance of both the batch and column methods achieved after regeneration (18.3 mg g⁻¹) was 25% higher than the estimated CEC values (13.0 mg g⁻¹) for the unregenerated samples of clinoptilolite. Comparison of CEC estimates using Pratley clinoptilolite, showed that average batch CEC estimates were significantly lower than the column method estimates. The average ammonia CEC values estimated in a fresh water recirculating system (5.80 mg g⁻¹ and 4.12 mg g⁻¹ for the 0.7-1.0 and 1.0-1.4 mm particle sizes, respectively) were significantly lower than the column and batch estimates for the same particle sizes (P < 0.05). Some nitrite (NO₂) and nitrate (NO3) build up was experienced probably due to the growth of autotrophs in the filters. Mass balance of nitrogen (N) for the three treatments of the fish trial (0.7-1.0 mm, 1.0-1.4 mm and the control treatment that had no zeolite in the filter) indicated that less that 10% of the N was retained for growth. It was found that 60% of the NH₄-N present associated with the soluble N was available for absorption by the zeolite filter or biological nitrification and that a total of approximately 22% of NH₄-N available was absorbed by clinoptilolite. The results indicate that the rate of nitrification can be deductively estimated by allowing a zeolite filter to become a biological filter. It is concluded that water treatment by ion exchange using natural zeolites, provides a reliable and efficient method for ammonia removal and appears to be a viable supplementary water treatment method for fresh water systems.
- Full Text:
- Date Issued: 2000
- Authors: Mwale, Monica
- Date: 2000
- Subjects: Ammonia -- Toxicology , Water -- Purification , Zeolites , Ion exchange
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5215 , http://hdl.handle.net/10962/d1005058 , Ammonia -- Toxicology , Water -- Purification , Zeolites , Ion exchange
- Description: One problem of intensive fish culture systems is the progressive build-up of toxic wastes such as ammonia. The possibility of improving aquaculture water quality using two kinds of zeolite is discussed. Zeolites are alumino-silicates whose framework allows them to exchange cations. Ion exchange has been demonstrated to be competitive with other methods of ammonia removal due to the high selectivity for ammonia exhibited by zeolite materials. In this study an unknown Zambian zeolite (identified as laumontite by X-ray diffraction techniques) and Pratley clinoptilolite (a South African zeolite) were tested under laboratory conditions and in a fresh water recirculating system. Ammonia cation exchange capacities (CEC) and suitable application rates for efficient water treatment were determined using the batch and column ion exchange procedures. Estimated ammonia uptake, the most important criterion used to assess performance of zeolite filters was strongly influenced by zeolite type, particle size, pre-treatment, regeneration and ion exchange method used. Statistical analysis showed significant differences in average ammonia CEC values between clinoptilolite (14.94 mg g⁻¹) and laumontite (2.77 mg g⁻¹), with the former displaying a higher Na⁺ ® NH₄⁺ exchange rate especially in the early reaction stages. This difference accords with the higher purity of clinoptilolite, 47% as opposed to 4.7% for laumontite, which makes it a better zeolite for ammonium removal. CEC increased linearly as particle size of the clinoptilolite was reduced resulting in a linear regression model (y = 18.29 – 3.704 x; r² = 74%). Pre-treatment of clinoptilolite using 1N NaCl significantly improved the ammonia CEC of clinoptilolite. Overall performance of both the batch and column methods achieved after regeneration (18.3 mg g⁻¹) was 25% higher than the estimated CEC values (13.0 mg g⁻¹) for the unregenerated samples of clinoptilolite. Comparison of CEC estimates using Pratley clinoptilolite, showed that average batch CEC estimates were significantly lower than the column method estimates. The average ammonia CEC values estimated in a fresh water recirculating system (5.80 mg g⁻¹ and 4.12 mg g⁻¹ for the 0.7-1.0 and 1.0-1.4 mm particle sizes, respectively) were significantly lower than the column and batch estimates for the same particle sizes (P < 0.05). Some nitrite (NO₂) and nitrate (NO3) build up was experienced probably due to the growth of autotrophs in the filters. Mass balance of nitrogen (N) for the three treatments of the fish trial (0.7-1.0 mm, 1.0-1.4 mm and the control treatment that had no zeolite in the filter) indicated that less that 10% of the N was retained for growth. It was found that 60% of the NH₄-N present associated with the soluble N was available for absorption by the zeolite filter or biological nitrification and that a total of approximately 22% of NH₄-N available was absorbed by clinoptilolite. The results indicate that the rate of nitrification can be deductively estimated by allowing a zeolite filter to become a biological filter. It is concluded that water treatment by ion exchange using natural zeolites, provides a reliable and efficient method for ammonia removal and appears to be a viable supplementary water treatment method for fresh water systems.
- Full Text:
- Date Issued: 2000
An evaluation of recirculating artificial stream designs for acute toxicity testing using two South African Ephemeroptera species exposed to sodium sulphate
- Authors: Binder, Markus
- Date: 2000
- Subjects: Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5690 , http://hdl.handle.net/10962/d1005376 , Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Description: Three artificial stream designs, termed Large Artificial Stream Units (LASUs), Raceways, and Channels, at two major scales (1700 L, 12.5 L and 20 L recirculated volume) were developed at the Institute for Water Research, Rhodes University, Grahamstown, in order to explore the possibilities of using indigenous rheophilic macroinvertebrates in routine toxicity tests. This study compared these systems, using 96h-EC50 values from sodium sulphate toxicity tests as the experimental response. Two local Ephemeroptera (Leptophlebiidae: Adenophlebia auriculata Eaton, and Baetidae: Afroptilum sudafricanum Lestage) were evaluated for their suitability in routine toxicity tests; and the possible effects of elevated salinity levels in South African rivers on the test species were assessed. Two sets of experiments with each mayfly species were conducted, following an unreplicated regression design. Dechlorinated tap water was used as the water source. Experiments in the Channels were repeated to determine experimental variability. Results were compared statistically by testing for overlap of 95% confidence limits (95%Cls) of EC50 values. The differences between A. auriculata EC50 values in the different systems were statistically significant (no overlap of 95%CLs), but they were not more variable than has been considered normal for biological systems (Coefficient of variation 20.1 %; ratio of greatest EC50 / smallest EC50 1.63). The differences were not related to the scale or the average current velocity characteristic of each stream design (average current velocity LASUs - Raceways - Channels 0.090 - 0.083 - 0.038 m/s). The Channels proved to be most efficient with regard to practical performance as they are portable and easily transportable, user-friendly, reliable, splash-free, cost effective to construct, and can easily be adapted to specific requirements. These systems are therefore recommended for regular use. The suitability of the two mayfly species for routine toxicity testing was evaluated. A. auriculata EC50 values showed a significant negative correlation with the corresponding average body-size (range 1476 - 1610 μm, mean 1555 μm). The different average body-sizes probably reflected the abundance of a certain size range present in the Palmiet River at the time of collection. Both species reacted similarly to Na₂S0₄ (similar slopes of the toxicity curves), identifying this salt as a slow acting toxicant. A. sudafricanum populations were more sensitive to Na₂S0₄ (EC50 3.404 g/L) than A. auriculata (EC50 8.090 g/L), probably because of its smaller body-size (mean 709 μm) and a lack of extremely tolerant individuals. In comparison to other freshwater macro invertebrates, including the standard toxicity test organism Daphnia spp., both mayfly species seemed to be moderately tolerant of Na₂S0₄; therefore there was no particular advantage to using these indigenous taxa rather than Daphnia spp. An assessment of the effects of elevated salinity/TDS levels on the test taxa yielded preliminary insights. A NaCI-EC50 for A. sudafricanum could be extrapolated and suggested a higher sensitivity to Na₂S0₄ than to NaCl. When Na₂S0₄ EC50 values of both species were compared to selected TDS levels of South African rivers, 4. auriculata would mostly not be affected, but A. sudafricanum might occasionally suffer from sub-lethal effects, depending on the sulphate proportion of the TDS. The South African guideline for TDS seemed to protect both species sufficiently.
- Full Text:
- Date Issued: 2000
- Authors: Binder, Markus
- Date: 2000
- Subjects: Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5690 , http://hdl.handle.net/10962/d1005376 , Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Description: Three artificial stream designs, termed Large Artificial Stream Units (LASUs), Raceways, and Channels, at two major scales (1700 L, 12.5 L and 20 L recirculated volume) were developed at the Institute for Water Research, Rhodes University, Grahamstown, in order to explore the possibilities of using indigenous rheophilic macroinvertebrates in routine toxicity tests. This study compared these systems, using 96h-EC50 values from sodium sulphate toxicity tests as the experimental response. Two local Ephemeroptera (Leptophlebiidae: Adenophlebia auriculata Eaton, and Baetidae: Afroptilum sudafricanum Lestage) were evaluated for their suitability in routine toxicity tests; and the possible effects of elevated salinity levels in South African rivers on the test species were assessed. Two sets of experiments with each mayfly species were conducted, following an unreplicated regression design. Dechlorinated tap water was used as the water source. Experiments in the Channels were repeated to determine experimental variability. Results were compared statistically by testing for overlap of 95% confidence limits (95%Cls) of EC50 values. The differences between A. auriculata EC50 values in the different systems were statistically significant (no overlap of 95%CLs), but they were not more variable than has been considered normal for biological systems (Coefficient of variation 20.1 %; ratio of greatest EC50 / smallest EC50 1.63). The differences were not related to the scale or the average current velocity characteristic of each stream design (average current velocity LASUs - Raceways - Channels 0.090 - 0.083 - 0.038 m/s). The Channels proved to be most efficient with regard to practical performance as they are portable and easily transportable, user-friendly, reliable, splash-free, cost effective to construct, and can easily be adapted to specific requirements. These systems are therefore recommended for regular use. The suitability of the two mayfly species for routine toxicity testing was evaluated. A. auriculata EC50 values showed a significant negative correlation with the corresponding average body-size (range 1476 - 1610 μm, mean 1555 μm). The different average body-sizes probably reflected the abundance of a certain size range present in the Palmiet River at the time of collection. Both species reacted similarly to Na₂S0₄ (similar slopes of the toxicity curves), identifying this salt as a slow acting toxicant. A. sudafricanum populations were more sensitive to Na₂S0₄ (EC50 3.404 g/L) than A. auriculata (EC50 8.090 g/L), probably because of its smaller body-size (mean 709 μm) and a lack of extremely tolerant individuals. In comparison to other freshwater macro invertebrates, including the standard toxicity test organism Daphnia spp., both mayfly species seemed to be moderately tolerant of Na₂S0₄; therefore there was no particular advantage to using these indigenous taxa rather than Daphnia spp. An assessment of the effects of elevated salinity/TDS levels on the test taxa yielded preliminary insights. A NaCI-EC50 for A. sudafricanum could be extrapolated and suggested a higher sensitivity to Na₂S0₄ than to NaCl. When Na₂S0₄ EC50 values of both species were compared to selected TDS levels of South African rivers, 4. auriculata would mostly not be affected, but A. sudafricanum might occasionally suffer from sub-lethal effects, depending on the sulphate proportion of the TDS. The South African guideline for TDS seemed to protect both species sufficiently.
- Full Text:
- Date Issued: 2000
The response of the two interrelated river components, geomorphology and riparian vegetation, to interbasin water transfers in the Orange-Fish-Sundays River Interbasin Transfer Scheme
- Authors: du Plessis, A J E
- Date: 2000
- Subjects: Skoenmakers River (South Africa) , Riparian ecology -- South Africa -- Eastern Cape , Geomorphology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4850 , http://hdl.handle.net/10962/d1005526
- Description: The Skoenmakers River (located in the semi-arid Karoo region of the Eastern Cape) is being used as a transfer route for water transferred by the Orange-Fish-Sundays River Interbasin Transfer Scheme. The change in the hydrological regime of this once ephemeral stream to a much bigger perennial river led to dramatic changes to both the physical structure and riparian vegetation structure of the river system. These changes differ for each of the three river sections, the upper,middle and lower reaches. Qualitative, descriptive geomorphological data was gathered by means of field observations and this was then compared to the quantitative data collected by means of surveyed cross-sectional profiles at selected sites along the length of both the regulated Skoenmakers River and a nonregulated tributary of equivalent size, the Volkers River. Riparian vegetation data was gathered by means of plot sampling along belt transects at each site. A qualitative assessment of the vegetation conditions was also made at each site and then added to the quantitative data from the plot sampling. At each site the different morphological units were identified along the cross-section and changes in the vegetation and sediment composition were recorded. Aerial photographs were used as additional sources of data and observations made from these were compared to data gathered in the field. The pre-IBT channel in this river section was formed by low frequency flood flows but the hydrological regime has now been converted to base flows much higher than normal flood flows. Severe incision, erosion and degradation of both the channel bed and banks occurred. In the lower reaches, post-IBT base flows are lower than pre-IBT flood flows and, due to the increased catchment area, the impact of the IBT was better ‘absorbed’ by the river system. Aggradation and deposition increased for the regulated river in comparison to the non-regulated river due to more sediment introduced The IBT had the greatest impact in the upper reaches of the regulated river due to more sediment introduced at the top of the system.
- Full Text:
- Date Issued: 2000
- Authors: du Plessis, A J E
- Date: 2000
- Subjects: Skoenmakers River (South Africa) , Riparian ecology -- South Africa -- Eastern Cape , Geomorphology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4850 , http://hdl.handle.net/10962/d1005526
- Description: The Skoenmakers River (located in the semi-arid Karoo region of the Eastern Cape) is being used as a transfer route for water transferred by the Orange-Fish-Sundays River Interbasin Transfer Scheme. The change in the hydrological regime of this once ephemeral stream to a much bigger perennial river led to dramatic changes to both the physical structure and riparian vegetation structure of the river system. These changes differ for each of the three river sections, the upper,middle and lower reaches. Qualitative, descriptive geomorphological data was gathered by means of field observations and this was then compared to the quantitative data collected by means of surveyed cross-sectional profiles at selected sites along the length of both the regulated Skoenmakers River and a nonregulated tributary of equivalent size, the Volkers River. Riparian vegetation data was gathered by means of plot sampling along belt transects at each site. A qualitative assessment of the vegetation conditions was also made at each site and then added to the quantitative data from the plot sampling. At each site the different morphological units were identified along the cross-section and changes in the vegetation and sediment composition were recorded. Aerial photographs were used as additional sources of data and observations made from these were compared to data gathered in the field. The pre-IBT channel in this river section was formed by low frequency flood flows but the hydrological regime has now been converted to base flows much higher than normal flood flows. Severe incision, erosion and degradation of both the channel bed and banks occurred. In the lower reaches, post-IBT base flows are lower than pre-IBT flood flows and, due to the increased catchment area, the impact of the IBT was better ‘absorbed’ by the river system. Aggradation and deposition increased for the regulated river in comparison to the non-regulated river due to more sediment introduced The IBT had the greatest impact in the upper reaches of the regulated river due to more sediment introduced at the top of the system.
- Full Text:
- Date Issued: 2000
Peer group supervision as an adjunct to individual supervision: an investigation of models of learning
- Akhurst, Jacqueline Elizabeth
- Authors: Akhurst, Jacqueline Elizabeth
- Date: 2000
- Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
- Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
- Full Text:
- Date Issued: 2000
- Authors: Akhurst, Jacqueline Elizabeth
- Date: 2000
- Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
- Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
- Full Text:
- Date Issued: 2000
An investigation into the influence of the environment on spawning aggregations and jig catches of chokka squid Loligo Vulgaris reynaudii off the south coast of South Africa
- Authors: Schön, Pieter-Jan
- Date: 2000
- Subjects: Squids -- Spawning , Squid fisheries -- South Africa , Squids , Shellfish fisheries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5378 , http://hdl.handle.net/10962/d1016369
- Description: Erratic and highly variable catches in the South African chokka squid Loligo vulgaris reynaudii fishery, cause socio-economic hardship for the industry and uncertainty for resource managers. Catch forecasting can reduce this problem as it is believed that catch variability is strongly influenced by environmental factors. In this study, data were collected at varying temporal and spatial scales. Data for the hourly time-scale study were collected from 1996-1998, aboard commercial vessels, whilst for the longer time-scales, data were extracted for Kromme Bay (a single fishing area) from existing databases (1991-1998) that were comprised of compulsory catch returns and oceanographic data. The environment-catch relationship for chokka squid on the inshore spawning grounds was then investigated using multiple correlation and regression analysis, analysis of variance, contingency table analysis and cross-correlation statistical techniques. This simple, direct, 'black box' statistical approach was relatively successful in developing a predictive capability. On a short time-scale (hourly), the regression model accounted for 32% of the variability in catch, with turbidity the main determinant (13%). On a daily monthly time-scale, the best prediction model was on a monthly scale, accounting for 40% of the variability in catch. The principal determinant, bottom temperature anomaly (11 %), was found to lag one month forward. Seasonal and diel catch variations induced changes in the relative importance of turbidity, water temperature and wind direction on catches. A strong, positive relationship was found between easterly winds (which cause upwelling) and catch, particularly in summer. Catch rates, however, decreased with an increase in turbidity. The correlation between temperature and catch was generally negative, however, higher catches were associated with a temperature range of 13-18°C. Highest catch rates were associated with easterly winds, zero turbidity conditions and sea surface temperatures from 15.0-16.9°C. Selected case studies (in situ observations) suggested that upwelling and turbidity events act as environmental triggers for the initiation or termination of the spawning process, respectively. A holistic approach is required to improve predictive capability of chokka squid abundance. Although short-term predictability remains essential (i.e. hourly-scale), future research should concentrate on long-term prediction models (e.g., monthly time-scales) involving greater spatial variation, which are the most important for management.
- Full Text:
- Date Issued: 2000
- Authors: Schön, Pieter-Jan
- Date: 2000
- Subjects: Squids -- Spawning , Squid fisheries -- South Africa , Squids , Shellfish fisheries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5378 , http://hdl.handle.net/10962/d1016369
- Description: Erratic and highly variable catches in the South African chokka squid Loligo vulgaris reynaudii fishery, cause socio-economic hardship for the industry and uncertainty for resource managers. Catch forecasting can reduce this problem as it is believed that catch variability is strongly influenced by environmental factors. In this study, data were collected at varying temporal and spatial scales. Data for the hourly time-scale study were collected from 1996-1998, aboard commercial vessels, whilst for the longer time-scales, data were extracted for Kromme Bay (a single fishing area) from existing databases (1991-1998) that were comprised of compulsory catch returns and oceanographic data. The environment-catch relationship for chokka squid on the inshore spawning grounds was then investigated using multiple correlation and regression analysis, analysis of variance, contingency table analysis and cross-correlation statistical techniques. This simple, direct, 'black box' statistical approach was relatively successful in developing a predictive capability. On a short time-scale (hourly), the regression model accounted for 32% of the variability in catch, with turbidity the main determinant (13%). On a daily monthly time-scale, the best prediction model was on a monthly scale, accounting for 40% of the variability in catch. The principal determinant, bottom temperature anomaly (11 %), was found to lag one month forward. Seasonal and diel catch variations induced changes in the relative importance of turbidity, water temperature and wind direction on catches. A strong, positive relationship was found between easterly winds (which cause upwelling) and catch, particularly in summer. Catch rates, however, decreased with an increase in turbidity. The correlation between temperature and catch was generally negative, however, higher catches were associated with a temperature range of 13-18°C. Highest catch rates were associated with easterly winds, zero turbidity conditions and sea surface temperatures from 15.0-16.9°C. Selected case studies (in situ observations) suggested that upwelling and turbidity events act as environmental triggers for the initiation or termination of the spawning process, respectively. A holistic approach is required to improve predictive capability of chokka squid abundance. Although short-term predictability remains essential (i.e. hourly-scale), future research should concentrate on long-term prediction models (e.g., monthly time-scales) involving greater spatial variation, which are the most important for management.
- Full Text:
- Date Issued: 2000
The universtiy in a developing free society : challenges to autonomy and academic freedom
- Authors: Makgoba, M W
- Date: 2000
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education, Higher -- Political aspects -- South Africa Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/684 , vital:19981
- Description: The real point of democratic reform, what I have been calling institutional reform, is not just to change the complexion of researchers, teachers and students, nor just to change the location of research and teaching, to be truly meaning- fill, reform has to lead to a change in the orientation of these activities. Let me take a hypothetical example, one where you succeed in adding more black and female faces to the research and leaching establishment and even to shifting the location of that establishment mainly to historically black universities - say your most advanced medical research facilities come to be located at the University of Fort Hare, with researchers mainly black and female, but the facility is still oriented to proton beam research for special types of cancer, away from the public health needs of the people - what will you have achieved? I dare say you would then have joined the ranks of independent Africa. The key issue will still remain not addressed: who should centres of research and learning serve and how? This is why I think the real challenge for all of us, whether south or north of the Limpopo, whether black or brown, yellow or white, is to begin thinking of how to root African universities in African soil.
- Full Text:
- Date Issued: 2000
- Authors: Makgoba, M W
- Date: 2000
- Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education, Higher -- Political aspects -- South Africa Education and state -- South Africa Education, Higher -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/684 , vital:19981
- Description: The real point of democratic reform, what I have been calling institutional reform, is not just to change the complexion of researchers, teachers and students, nor just to change the location of research and teaching, to be truly meaning- fill, reform has to lead to a change in the orientation of these activities. Let me take a hypothetical example, one where you succeed in adding more black and female faces to the research and leaching establishment and even to shifting the location of that establishment mainly to historically black universities - say your most advanced medical research facilities come to be located at the University of Fort Hare, with researchers mainly black and female, but the facility is still oriented to proton beam research for special types of cancer, away from the public health needs of the people - what will you have achieved? I dare say you would then have joined the ranks of independent Africa. The key issue will still remain not addressed: who should centres of research and learning serve and how? This is why I think the real challenge for all of us, whether south or north of the Limpopo, whether black or brown, yellow or white, is to begin thinking of how to root African universities in African soil.
- Full Text:
- Date Issued: 2000