Development of a hydantoin-hydrolysing biocatalyst for the production of optically pure amino acids using Agrobacterium tumefaciens strain RU-ORPN1
- Authors: Foster, Ingrid Margaret
- Date: 2004
- Subjects: Agrobacterium tumefaciens Amino acids Hydantoin Hydrolysis Enzymes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3943 , http://hdl.handle.net/10962/d1004002
- Description: A calcium alginate bead-immobilised biocatalyst was developed utilising the D-hydantoinase and D-N-carbamoylase from a novel, mutant Agrobacterium tumefaciens strain RU-ORPN1. The growth conditions for the inducer-independent strain were optimised for production of hydantoinase and N-carbamoylase activities. Methods for the preparation of crude enzyme extracts were evaluated in terms of hydantoinase and N-carbamoylase activities produced. After comparison of the enzyme activities and stabilities in various extracts from fresh and frozen cells, sonication of frozen cells for 5 minutes was found to be the best method for the production of the enzyme extract. The optimal pH and temperature for the hydantoinase activity were pH 10 and 30°C, respectively, while pH 9 and 40°C were optimal for Ncarbamoylase activity. The hydantoinase activity was enhanced by the addition of Mg^(2+) ions to the enzyme extract and the N-carbamoylase was enhanced by the addition of Mg^(2+), Mn^(2+) or Zn^(2+) ions to the enzyme extract. The enzyme activities increased in the presence of ATP suggesting that the enzymes may be ATP-dependent. The addition of DTT and PMSF to the enzyme extract enhanced the hydantoinase activity but had no effect on the N-carbamoylase activity. The N-carbamoylase was unstable at 40°C and was almost completely inactivated after 24 hours incubation at this temperature. The hydantoinase and N-carbamoylase appeared to be insoluble. Various techniques were investigated for the solubilisation of the enzymes including various cell lysis methods, cell lysis at extremes of pH and ionic strength, addition of a reducing agent and protease inhibitors, and treatment with hydrolysing enzymes and detergents. Treatment with Triton X-100 was most effective for the solubilisation of the enzymes indicating that the enzymes were membrane-bound. Hydropathy and transmembrane prediction plots of the predicted amino acid sequences for two identified N-carbamoylase genes from A. tumefaciens RU-ORPN1 revealed possible transmembrane regions in the amino acid sequences, and thus supported the hypothesis that the enzymes were membrane-bound. Various methods were evaluated for the immobilisation of the enzymes in whole cells and enzyme extracts. Immobilisation of the enzyme extract in calcium alginate beads was found to be the best method in terms of enzyme activity retention and stability. The hydantoinase retained 55% activity while the N-carbamoylase exhibited a remarkable sevenfold increase in activity after immobilisation by this method. Furthermore, the hydantoinase activity increased after storage at 4°C for 21 days, while the N-carbamoylase retained 30% activity after this storage period. The calcium alginate bead-immobilised enzymes were further biochemically characterised and then applied in a bioreactor system for the production of D-hydroxyphenylglycine (D-HPG) from D,L-5-hydroxyphenylhydantoin (D,L-5-HPH). The pH and temperature optima for the immobilised hydantoinase were pH 7 and 50°C, respectively, while pH 8 and 40°C were optimal for the immobilised N-carbamoylase enzyme. The immobilised enzymes showed improved thermostability at 40°C in comparison to the free enzymes and retained high levels of activity after five repeated batch reactions. Low levels of conversion were obtained in a packed-bed bioreactor containing the A. tumefaciens RU-ORPN1 biocatalyst due to the low hydantoinase activity present in the strain, relative to N-carbamoylase. A novel, packed-bed bioreactor system was therefore developed for the production of D-HPG from D,L-5-HPH using the A. tumefaciens biocatalyst in combination with a Pseudomonas sp. biocatalyst having high hydantoinase activity. A conversion yield of 22 to 30% was achieved for the production of D-HPG from D,L-5-HPH over 5 days operation demonstrating that the hydantoin-hydrolysing enzymes from A. tumefaciens RU-ORPN1 could be stabilised by immobilisation and, in combination with a biocatalyst with high hydantoinase activity, could be applied to the fully enzymatic conversion of D,L-5-HPH to D-HPG.
- Full Text:
- Date Issued: 2004
- Authors: Foster, Ingrid Margaret
- Date: 2004
- Subjects: Agrobacterium tumefaciens Amino acids Hydantoin Hydrolysis Enzymes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3943 , http://hdl.handle.net/10962/d1004002
- Description: A calcium alginate bead-immobilised biocatalyst was developed utilising the D-hydantoinase and D-N-carbamoylase from a novel, mutant Agrobacterium tumefaciens strain RU-ORPN1. The growth conditions for the inducer-independent strain were optimised for production of hydantoinase and N-carbamoylase activities. Methods for the preparation of crude enzyme extracts were evaluated in terms of hydantoinase and N-carbamoylase activities produced. After comparison of the enzyme activities and stabilities in various extracts from fresh and frozen cells, sonication of frozen cells for 5 minutes was found to be the best method for the production of the enzyme extract. The optimal pH and temperature for the hydantoinase activity were pH 10 and 30°C, respectively, while pH 9 and 40°C were optimal for Ncarbamoylase activity. The hydantoinase activity was enhanced by the addition of Mg^(2+) ions to the enzyme extract and the N-carbamoylase was enhanced by the addition of Mg^(2+), Mn^(2+) or Zn^(2+) ions to the enzyme extract. The enzyme activities increased in the presence of ATP suggesting that the enzymes may be ATP-dependent. The addition of DTT and PMSF to the enzyme extract enhanced the hydantoinase activity but had no effect on the N-carbamoylase activity. The N-carbamoylase was unstable at 40°C and was almost completely inactivated after 24 hours incubation at this temperature. The hydantoinase and N-carbamoylase appeared to be insoluble. Various techniques were investigated for the solubilisation of the enzymes including various cell lysis methods, cell lysis at extremes of pH and ionic strength, addition of a reducing agent and protease inhibitors, and treatment with hydrolysing enzymes and detergents. Treatment with Triton X-100 was most effective for the solubilisation of the enzymes indicating that the enzymes were membrane-bound. Hydropathy and transmembrane prediction plots of the predicted amino acid sequences for two identified N-carbamoylase genes from A. tumefaciens RU-ORPN1 revealed possible transmembrane regions in the amino acid sequences, and thus supported the hypothesis that the enzymes were membrane-bound. Various methods were evaluated for the immobilisation of the enzymes in whole cells and enzyme extracts. Immobilisation of the enzyme extract in calcium alginate beads was found to be the best method in terms of enzyme activity retention and stability. The hydantoinase retained 55% activity while the N-carbamoylase exhibited a remarkable sevenfold increase in activity after immobilisation by this method. Furthermore, the hydantoinase activity increased after storage at 4°C for 21 days, while the N-carbamoylase retained 30% activity after this storage period. The calcium alginate bead-immobilised enzymes were further biochemically characterised and then applied in a bioreactor system for the production of D-hydroxyphenylglycine (D-HPG) from D,L-5-hydroxyphenylhydantoin (D,L-5-HPH). The pH and temperature optima for the immobilised hydantoinase were pH 7 and 50°C, respectively, while pH 8 and 40°C were optimal for the immobilised N-carbamoylase enzyme. The immobilised enzymes showed improved thermostability at 40°C in comparison to the free enzymes and retained high levels of activity after five repeated batch reactions. Low levels of conversion were obtained in a packed-bed bioreactor containing the A. tumefaciens RU-ORPN1 biocatalyst due to the low hydantoinase activity present in the strain, relative to N-carbamoylase. A novel, packed-bed bioreactor system was therefore developed for the production of D-HPG from D,L-5-HPH using the A. tumefaciens biocatalyst in combination with a Pseudomonas sp. biocatalyst having high hydantoinase activity. A conversion yield of 22 to 30% was achieved for the production of D-HPG from D,L-5-HPH over 5 days operation demonstrating that the hydantoin-hydrolysing enzymes from A. tumefaciens RU-ORPN1 could be stabilised by immobilisation and, in combination with a biocatalyst with high hydantoinase activity, could be applied to the fully enzymatic conversion of D,L-5-HPH to D-HPG.
- Full Text:
- Date Issued: 2004
Die bestuursrol van die skoolhoof in die implementering van 'n nuwe kurrikulum
- Authors: Mey, Hermanus Pieter
- Date: 2004
- Subjects: School principals -- South Africa , Educational leadership -- South Africa , Curriculum change -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MPhil
- Identifier: vital:11010 , http://hdl.handle.net/10948/367 , School principals -- South Africa , Educational leadership -- South Africa , Curriculum change -- South Africa
- Description: The implementation of a new curriculum has become a very relevant issue in South Africa with the implementation of Curriculum 2005 (C 2005) since 1998. The school principal plays a very important role at school level in the implementation of change in general and a new curriculum in particular. The aim of this study was to have a closer look at this role. It is a qualitative study executed in six schools in the Port Elizabeth area. It investigates the problems school principals experienced with the implementation of C 2005 with the objective of identifying guidelines for the role of the principal in the implementation of a new curriculum The most important findings include the importance of equipping the principal to provide guidance with the implementation of a new curriculum. This equipping refers to the principal’s knowledge of the new curriculum, the ability to employ various leadership styles, as well as the maintenance of a certain balance between supporting and putting pressure on the staff. Other findings refer to the importance of well-trained and prepared facilitators of workshops, as well as the role the Department of Education needs to play in the training and preparation of these facilitators. The ongoing support of schools in the implementation process also needs to be emphasized. The principal should play a key role with respect to this last role of the Department. The study also emphasizes the principal’s responsibility to bind the educators together in building a shared vision, so that their focus will remain on the curriculum implementation.
- Full Text:
- Date Issued: 2004
- Authors: Mey, Hermanus Pieter
- Date: 2004
- Subjects: School principals -- South Africa , Educational leadership -- South Africa , Curriculum change -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MPhil
- Identifier: vital:11010 , http://hdl.handle.net/10948/367 , School principals -- South Africa , Educational leadership -- South Africa , Curriculum change -- South Africa
- Description: The implementation of a new curriculum has become a very relevant issue in South Africa with the implementation of Curriculum 2005 (C 2005) since 1998. The school principal plays a very important role at school level in the implementation of change in general and a new curriculum in particular. The aim of this study was to have a closer look at this role. It is a qualitative study executed in six schools in the Port Elizabeth area. It investigates the problems school principals experienced with the implementation of C 2005 with the objective of identifying guidelines for the role of the principal in the implementation of a new curriculum The most important findings include the importance of equipping the principal to provide guidance with the implementation of a new curriculum. This equipping refers to the principal’s knowledge of the new curriculum, the ability to employ various leadership styles, as well as the maintenance of a certain balance between supporting and putting pressure on the staff. Other findings refer to the importance of well-trained and prepared facilitators of workshops, as well as the role the Department of Education needs to play in the training and preparation of these facilitators. The ongoing support of schools in the implementation process also needs to be emphasized. The principal should play a key role with respect to this last role of the Department. The study also emphasizes the principal’s responsibility to bind the educators together in building a shared vision, so that their focus will remain on the curriculum implementation.
- Full Text:
- Date Issued: 2004
Die toepassing van die proses van geïntegreerde ontwikkelingsbeplanning deur kategorie B plaaslike owerhede
- Authors: Els, Christoffel Gerhardus
- Date: 2004
- Subjects: Local government -- South Africa , Public administration -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MTech (Public Management)
- Identifier: vital:10768 , http://hdl.handle.net/10948/266 , Local government -- South Africa , Public administration -- South Africa
- Description: Samevattende oorsig: In hierdie skripsie, is 'n studie onderneem ten opsigte van die Geïntegreerde Ontwikkelingsbeplanningsproses, wat die proses van beplanning en die toepassing van hierdie beplanningsresultate ten opsigte van twee klein B-munisipaliteite in die Wes-Kaap Provinsie insluit. Die skripsie bestaan uit sewe hoofstukke en is gebaseer op die veronderstelling dat die beplanningsproses van so 'n tegniese aard is dat kleiner owerhede nie in staat is om die proses na behore te kan bestuur nie. Dit gaan verder van die onderstelling uit dat die implementeeringskapasiteit by kleiner owerhede ontbreek om dievoorsiene uitkomste na behore te realiseer. Die primêre doelwitte van die navorsing sluit die volgende in: 'n basiese oorsig van openbare bestuur, die rolle en funksies van funksionarisse binne hierdie omgewing en die veranderende aard van openbare bestuur. Die proses van geïntegreerde ontwikkelingsbeplanning binne plaaslike regering word bestudeer met 'n volledige proses toeligting. Die noodsaaklikheid van beplanning en prestasiebestuur word bevestig tesame met die uitdagings en probleme wat die nuwe benadering bring aan klein plaaslike owerhede. 'n Finale waardebepaling rond die studie af. Die studie bestaan uit bronnavorsing om die veranderende aard van openbare bestuur toe te lig tesame met die werklike aard van die beplanningsproses soos vereis binne relevante wetgewing. Die impak van hierdie vereistes op klein plaaslike owerhede in die Wes-Kaap word ontleed aan die hand van twee geïntegreerde ontwikkelingsplanne soos deur die skrywer hiervan gefasiliteer by dié owerhede. Die gevolgtrekkings gemaak uit hierdie studie word dan ook aangedui met 'n aanbeveling oor die mees sinvolle inkrementele benadering ten opsigte van ontwikkeling as proses en die deelname van rolspelers daarbinne.
- Full Text:
- Date Issued: 2004
- Authors: Els, Christoffel Gerhardus
- Date: 2004
- Subjects: Local government -- South Africa , Public administration -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MTech (Public Management)
- Identifier: vital:10768 , http://hdl.handle.net/10948/266 , Local government -- South Africa , Public administration -- South Africa
- Description: Samevattende oorsig: In hierdie skripsie, is 'n studie onderneem ten opsigte van die Geïntegreerde Ontwikkelingsbeplanningsproses, wat die proses van beplanning en die toepassing van hierdie beplanningsresultate ten opsigte van twee klein B-munisipaliteite in die Wes-Kaap Provinsie insluit. Die skripsie bestaan uit sewe hoofstukke en is gebaseer op die veronderstelling dat die beplanningsproses van so 'n tegniese aard is dat kleiner owerhede nie in staat is om die proses na behore te kan bestuur nie. Dit gaan verder van die onderstelling uit dat die implementeeringskapasiteit by kleiner owerhede ontbreek om dievoorsiene uitkomste na behore te realiseer. Die primêre doelwitte van die navorsing sluit die volgende in: 'n basiese oorsig van openbare bestuur, die rolle en funksies van funksionarisse binne hierdie omgewing en die veranderende aard van openbare bestuur. Die proses van geïntegreerde ontwikkelingsbeplanning binne plaaslike regering word bestudeer met 'n volledige proses toeligting. Die noodsaaklikheid van beplanning en prestasiebestuur word bevestig tesame met die uitdagings en probleme wat die nuwe benadering bring aan klein plaaslike owerhede. 'n Finale waardebepaling rond die studie af. Die studie bestaan uit bronnavorsing om die veranderende aard van openbare bestuur toe te lig tesame met die werklike aard van die beplanningsproses soos vereis binne relevante wetgewing. Die impak van hierdie vereistes op klein plaaslike owerhede in die Wes-Kaap word ontleed aan die hand van twee geïntegreerde ontwikkelingsplanne soos deur die skrywer hiervan gefasiliteer by dié owerhede. Die gevolgtrekkings gemaak uit hierdie studie word dan ook aangedui met 'n aanbeveling oor die mees sinvolle inkrementele benadering ten opsigte van ontwikkeling as proses en die deelname van rolspelers daarbinne.
- Full Text:
- Date Issued: 2004
Discourse domination?: the role of gender in seminar interaction
- De Klerk, Vivian A, Hunt, Sally
- Authors: De Klerk, Vivian A , Hunt, Sally
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139160 , vital:37710 , https://www.ajol.info/index.php/salas/article/view/6501
- Description: This paper focuses on the effect of the gender of participants on the discourse patterns of university seminars, and compares the interaction patterns in two undergraduate seminars with those in two post-graduate seminars at Rhodes University. In the undergraduate seminars, two different groups of students at first year level in different disciplines were videotaped. The major difference was in terms of composition: in one seminar, there were equal numbers of male and female students, while in the other, female students dominated numerically (75%). In addition, five of the six formed a close-knit group of friends, which proved to be an important factor in the analysis. At the postgraduate level, the student participants were identical and met in the same venue and at the same time on two successive days to discuss the same topic (affirmative action in the workplace). The important difference between the two classes was the fact that the first seminar was led by a female tutor and the second seminar by a male tutor, both under 40 years of age and white, both members of staff in the department, and both known to the students. The discourse patterns in these two sets of seminars were analysed in order to investigate the ways in which the gender of tutors and students influenced the floor-winning and floor-holding conventions of participants.
- Full Text:
- Date Issued: 2004
- Authors: De Klerk, Vivian A , Hunt, Sally
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/139160 , vital:37710 , https://www.ajol.info/index.php/salas/article/view/6501
- Description: This paper focuses on the effect of the gender of participants on the discourse patterns of university seminars, and compares the interaction patterns in two undergraduate seminars with those in two post-graduate seminars at Rhodes University. In the undergraduate seminars, two different groups of students at first year level in different disciplines were videotaped. The major difference was in terms of composition: in one seminar, there were equal numbers of male and female students, while in the other, female students dominated numerically (75%). In addition, five of the six formed a close-knit group of friends, which proved to be an important factor in the analysis. At the postgraduate level, the student participants were identical and met in the same venue and at the same time on two successive days to discuss the same topic (affirmative action in the workplace). The important difference between the two classes was the fact that the first seminar was led by a female tutor and the second seminar by a male tutor, both under 40 years of age and white, both members of staff in the department, and both known to the students. The discourse patterns in these two sets of seminars were analysed in order to investigate the ways in which the gender of tutors and students influenced the floor-winning and floor-holding conventions of participants.
- Full Text:
- Date Issued: 2004
Dismissal for medical incapacity
- Authors: Boy, Anthony Albert
- Date: 2004
- Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Capacity and disability -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11047 , http://hdl.handle.net/10948/316 , Employees -- Dismissal of -- Law and legislation -- South Africa , Capacity and disability -- South Africa , Labor laws and legislation -- South Africa
- Description: Labour law in South Africa has evolved over the past century at an ever increasing pace. The establishment of a democratic government in 1995 has been the trigger for a large number of labour law statutes being promulgated, particularly with reference to the laws governing the employment relationship and dismissal. From very humble and employer biased dispute resolution application under the common law of contract, labour law in this country has evolved through the various acts culminating in a labour law system which is highly regulated and codified. Dismissal for medical incapacity in this treatise is reviewed with regard to the applicable statutes and the various codes of good practice as the law has evolved and developed from the period covered by the common law through that covered by the 1995 LRA up to and including the current period. Particular attention is paid to both substantive and procedural requirements as well as the remedies applicable under the different legal regimes and the pertinent tribunals and courts. Regard is also given to the duration and causes of incapacity and the effect this may have on the applicable remedy applied by these tribunals. It will become apparant that the medically incapacitated employee occupied a relatively weak and vulnerable position under the common law as opposed to the current position under the 1995 LRA. The influence of the remedies applied by the tribunals under the 1956 LRA are clearly evident in the current regulations and codes under the 1995 LRA which contain specific statutory provisions for employees not to be unfairly dismissed. Distinctions are drawn between permissible and impermissible dismissals, with medical incapacity falling under the former. v Furthermore, a distinction is drawn statutorily between permanent and temporary illhealth/ injury incapacity with detailed guidelines for substantive and procedural fairness requirements to be met by employers. The powers of the specialist tribunals (CCMA, Bargaining Councils and Labour Courts) are regulated by statutory provisions and deal with appropriate remedies (reinstatement and/or compensation) a wardable in appropriate circumstances. Certain specific areas nonetheless still remain problematic for these tribunals and hence questions that require clear direction from the drafters of our law are: 1. How to distinguish misconduct in alcohol and drug abuse cases? 2. What degree of intermittent absenteeism is required before dismissal would be warranted? In certain other areas the tribunals have been fairly consistent and prescriptive in their approach and remedies awarded. Included here would be permanent incapacity, HIV cases and misconduct. It will emerge, however, that under the 1995 LRA the position of employees and the protections afforded them have been greatly increased.
- Full Text:
- Date Issued: 2004
- Authors: Boy, Anthony Albert
- Date: 2004
- Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Capacity and disability -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11047 , http://hdl.handle.net/10948/316 , Employees -- Dismissal of -- Law and legislation -- South Africa , Capacity and disability -- South Africa , Labor laws and legislation -- South Africa
- Description: Labour law in South Africa has evolved over the past century at an ever increasing pace. The establishment of a democratic government in 1995 has been the trigger for a large number of labour law statutes being promulgated, particularly with reference to the laws governing the employment relationship and dismissal. From very humble and employer biased dispute resolution application under the common law of contract, labour law in this country has evolved through the various acts culminating in a labour law system which is highly regulated and codified. Dismissal for medical incapacity in this treatise is reviewed with regard to the applicable statutes and the various codes of good practice as the law has evolved and developed from the period covered by the common law through that covered by the 1995 LRA up to and including the current period. Particular attention is paid to both substantive and procedural requirements as well as the remedies applicable under the different legal regimes and the pertinent tribunals and courts. Regard is also given to the duration and causes of incapacity and the effect this may have on the applicable remedy applied by these tribunals. It will become apparant that the medically incapacitated employee occupied a relatively weak and vulnerable position under the common law as opposed to the current position under the 1995 LRA. The influence of the remedies applied by the tribunals under the 1956 LRA are clearly evident in the current regulations and codes under the 1995 LRA which contain specific statutory provisions for employees not to be unfairly dismissed. Distinctions are drawn between permissible and impermissible dismissals, with medical incapacity falling under the former. v Furthermore, a distinction is drawn statutorily between permanent and temporary illhealth/ injury incapacity with detailed guidelines for substantive and procedural fairness requirements to be met by employers. The powers of the specialist tribunals (CCMA, Bargaining Councils and Labour Courts) are regulated by statutory provisions and deal with appropriate remedies (reinstatement and/or compensation) a wardable in appropriate circumstances. Certain specific areas nonetheless still remain problematic for these tribunals and hence questions that require clear direction from the drafters of our law are: 1. How to distinguish misconduct in alcohol and drug abuse cases? 2. What degree of intermittent absenteeism is required before dismissal would be warranted? In certain other areas the tribunals have been fairly consistent and prescriptive in their approach and remedies awarded. Included here would be permanent incapacity, HIV cases and misconduct. It will emerge, however, that under the 1995 LRA the position of employees and the protections afforded them have been greatly increased.
- Full Text:
- Date Issued: 2004
Dismissal for medical incapacity
- Authors: Boy, Anthony Albert
- Date: 2004
- Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Capacity and disability -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10242 , http://hdl.handle.net/10948/d1016262
- Description: Labour law in South Africa has evolved over the past century at an ever increasing pace. The establishment of a democratic government in 1995 has been the trigger for a large number of labour law statutes being promulgated, particularly with reference to the laws governing the employment relationship and dismissal. From very humble and employer biased dispute resolution application under the common law of contract, labour law in this country has evolved through the various acts culminating in a labour law system which is highly regulated and codified. Dismissal for medical incapacity in this treatise is reviewed with regard to the applicable statutes and the various codes of good practice as the law has evolved and developed from the period covered by the common law through that covered by the 1995 LRA up to and including the current period. Particular attention is paid to both substantive and procedural requirements as well as the remedies applicable under the different legal regimes and the pertinent tribunals and courts. Regard is also given to the duration and causes of incapacity and the effect this may have on the applicable remedy applied by these tribunals. It will become apparant that the medically incapacitated employee occupied a relatively weak and vulnerable position under the common law as opposed to the current position under the 1995 LRA. The influence of the remedies applied by the tribunals under the 1956 LRA are clearly evident in the current regulations and codes under the 1995 LRA which contain specific statutory provisions for employees not to be unfairly dismissed. Distinctions are drawn between permissible and impermissible dismissals, with medical incapacity falling under the former. Furthermore, a distinction is drawn statutorily between permanent and temporary illhealth/injury incapacity with detailed guidelines for substantive and procedural fairness requirements to be met by employers. The powers of the specialist tribunals (CCMA, Bargaining Councils and Labour Courts) are regulated by statutory provisions and deal with appropriate remedies (reinstatement and/or compensation) a wardable in appropriate circumstances. Certain specific areas nonetheless still remain problematic for these tribunals and hence questions that require clear direction from the drafters of our law are: How to distinguish misconduct in alcohol and drug abuse cases? What degree of intermittent absenteeism is required before dismissal would be warranted? In certain other areas the tribunals have been fairly consistent and prescriptive in their approach and remedies awarded. Included here would be permanent incapacity, HIV cases and misconduct. It will emerge, however, that under the 1995 LRA the position of employees and the protections afforded them have been greatly increased.
- Full Text:
- Date Issued: 2004
- Authors: Boy, Anthony Albert
- Date: 2004
- Subjects: Employees -- Dismissal of -- Law and legislation -- South Africa , Capacity and disability -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10242 , http://hdl.handle.net/10948/d1016262
- Description: Labour law in South Africa has evolved over the past century at an ever increasing pace. The establishment of a democratic government in 1995 has been the trigger for a large number of labour law statutes being promulgated, particularly with reference to the laws governing the employment relationship and dismissal. From very humble and employer biased dispute resolution application under the common law of contract, labour law in this country has evolved through the various acts culminating in a labour law system which is highly regulated and codified. Dismissal for medical incapacity in this treatise is reviewed with regard to the applicable statutes and the various codes of good practice as the law has evolved and developed from the period covered by the common law through that covered by the 1995 LRA up to and including the current period. Particular attention is paid to both substantive and procedural requirements as well as the remedies applicable under the different legal regimes and the pertinent tribunals and courts. Regard is also given to the duration and causes of incapacity and the effect this may have on the applicable remedy applied by these tribunals. It will become apparant that the medically incapacitated employee occupied a relatively weak and vulnerable position under the common law as opposed to the current position under the 1995 LRA. The influence of the remedies applied by the tribunals under the 1956 LRA are clearly evident in the current regulations and codes under the 1995 LRA which contain specific statutory provisions for employees not to be unfairly dismissed. Distinctions are drawn between permissible and impermissible dismissals, with medical incapacity falling under the former. Furthermore, a distinction is drawn statutorily between permanent and temporary illhealth/injury incapacity with detailed guidelines for substantive and procedural fairness requirements to be met by employers. The powers of the specialist tribunals (CCMA, Bargaining Councils and Labour Courts) are regulated by statutory provisions and deal with appropriate remedies (reinstatement and/or compensation) a wardable in appropriate circumstances. Certain specific areas nonetheless still remain problematic for these tribunals and hence questions that require clear direction from the drafters of our law are: How to distinguish misconduct in alcohol and drug abuse cases? What degree of intermittent absenteeism is required before dismissal would be warranted? In certain other areas the tribunals have been fairly consistent and prescriptive in their approach and remedies awarded. Included here would be permanent incapacity, HIV cases and misconduct. It will emerge, however, that under the 1995 LRA the position of employees and the protections afforded them have been greatly increased.
- Full Text:
- Date Issued: 2004
Distinct kimberlite pipe classes with contrasting eruption processes
- Skinner, E M W, Marsh, Julian S
- Authors: Skinner, E M W , Marsh, Julian S
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150603 , vital:38988 , https://doi.org/10.1016/j.lithos.2004.03.044
- Description: Field and Scott Smith [Field, M., Scott Smith, B.H., 1999. Contrasting geology and near-surface emplacement of kimberlite pipes in southern Africa and Canada. Proc. 7th Int. Kimb. Conf. (Eds. Gurney et al.) 1, 214–237.] propose that kimberlite pipes can be grouped into three types or classes. Classical or Class 1 pipes are the only class with characteristic low temperature, diatreme-facies kimberlite in addition to hypabyssal- and crater-facies kimberlite. Class 2 and 3 pipes are characterized only by hypabyssal-and crater-facies kimberlite.
- Full Text: false
- Date Issued: 2004
- Authors: Skinner, E M W , Marsh, Julian S
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150603 , vital:38988 , https://doi.org/10.1016/j.lithos.2004.03.044
- Description: Field and Scott Smith [Field, M., Scott Smith, B.H., 1999. Contrasting geology and near-surface emplacement of kimberlite pipes in southern Africa and Canada. Proc. 7th Int. Kimb. Conf. (Eds. Gurney et al.) 1, 214–237.] propose that kimberlite pipes can be grouped into three types or classes. Classical or Class 1 pipes are the only class with characteristic low temperature, diatreme-facies kimberlite in addition to hypabyssal- and crater-facies kimberlite. Class 2 and 3 pipes are characterized only by hypabyssal-and crater-facies kimberlite.
- Full Text: false
- Date Issued: 2004
Drimia chalumnensis (Hyacinthaceae - Urgineoideae), a new species from Eastern Cape, South Africa
- Dold, Anthony P, Brink, Estelle
- Authors: Dold, Anthony P , Brink, Estelle
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6516 , http://hdl.handle.net/10962/d1005944
- Description: Drimia chalumnensis, a new inconspicuous dwarf species from the Albany Centre of Floristic Endemism in Eastern Cape, South Africa, is restricted to the coastal plains of the Chalumna river in small scattered aggregated colonies on exposed sandstone sheets in pockets of loose sandy soil. It is distinguished by its capitate inflorescence, separate, petiolate bulb scales, and prostrate, coriaceous, linear-lanceolate leaves with cartilaginous margins.
- Full Text:
- Date Issued: 2004
- Authors: Dold, Anthony P , Brink, Estelle
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6516 , http://hdl.handle.net/10962/d1005944
- Description: Drimia chalumnensis, a new inconspicuous dwarf species from the Albany Centre of Floristic Endemism in Eastern Cape, South Africa, is restricted to the coastal plains of the Chalumna river in small scattered aggregated colonies on exposed sandstone sheets in pockets of loose sandy soil. It is distinguished by its capitate inflorescence, separate, petiolate bulb scales, and prostrate, coriaceous, linear-lanceolate leaves with cartilaginous margins.
- Full Text:
- Date Issued: 2004
DRUBIS : a distributed face-identification experimentation framework - design, implementation and performance issues
- Authors: Ndlangisa, Mboneli
- Date: 2004
- Subjects: Principal components analysis , Human face recognition (Computer science) , Image processing , Biometric identification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4704 , http://hdl.handle.net/10962/d1015768
- Description: We report on the design, implementation and performance issues of the DRUBIS (Distributed Rhodes University Biometric Identification System) experimentation framework. The Principal Component Analysis (PCA) face-recognition approach is used as a case study. DRUBIS is a flexible experimentation framework, distributed over a number of modules that are easily pluggable and swappable, allowing for the easy construction of prototype systems. Web services are the logical means of distributing DRUBIS components and a number of prototype applications have been implemented from this framework. Different popular PCA face-recognition related experiments were used to evaluate our experimentation framework. We extract recognition performance measures from these experiments. In particular, we use the framework for a more indepth study of the suitability of the DFFS (Difference From Face Space) metric as a means for image classification in the area of race and gender determination.
- Full Text:
- Date Issued: 2004
- Authors: Ndlangisa, Mboneli
- Date: 2004
- Subjects: Principal components analysis , Human face recognition (Computer science) , Image processing , Biometric identification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4704 , http://hdl.handle.net/10962/d1015768
- Description: We report on the design, implementation and performance issues of the DRUBIS (Distributed Rhodes University Biometric Identification System) experimentation framework. The Principal Component Analysis (PCA) face-recognition approach is used as a case study. DRUBIS is a flexible experimentation framework, distributed over a number of modules that are easily pluggable and swappable, allowing for the easy construction of prototype systems. Web services are the logical means of distributing DRUBIS components and a number of prototype applications have been implemented from this framework. Different popular PCA face-recognition related experiments were used to evaluate our experimentation framework. We extract recognition performance measures from these experiments. In particular, we use the framework for a more indepth study of the suitability of the DFFS (Difference From Face Space) metric as a means for image classification in the area of race and gender determination.
- Full Text:
- Date Issued: 2004
Early development of water quality methods and approaches in ecological Reserve assessments
- Palmer, Carolyn G, Scherman, Patricia, Muller, Nikite W J, Rossouw, J N, Malan, H L, Jooste, S
- Authors: Palmer, Carolyn G , Scherman, Patricia , Muller, Nikite W J , Rossouw, J N , Malan, H L , Jooste, S
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437840 , vital:73416 , ISBN 1-77005-227-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/1108-1-041.pdf
- Description: This project was initiated in 2000 to allow the ecological Reserve team for water quality to undertake additional research while working on eco-logical Reserve determinations funded by the Department of Water Af-fairs and Forestry. The results of this work form the basis of the meth-ods reported in the Water Research Commission report Hughes DA (Ed)(in press).
- Full Text:
- Date Issued: 2004
- Authors: Palmer, Carolyn G , Scherman, Patricia , Muller, Nikite W J , Rossouw, J N , Malan, H L , Jooste, S
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437840 , vital:73416 , ISBN 1-77005-227-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/1108-1-041.pdf
- Description: This project was initiated in 2000 to allow the ecological Reserve team for water quality to undertake additional research while working on eco-logical Reserve determinations funded by the Department of Water Af-fairs and Forestry. The results of this work form the basis of the meth-ods reported in the Water Research Commission report Hughes DA (Ed)(in press).
- Full Text:
- Date Issued: 2004
Economic feasibility of an experimental octopus fishery in South Africa
- Authors: Oosthuizen, Ané
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6760 , http://hdl.handle.net/10962/d1007773
- Description: Octopus vulgaris was identified as a new marine resource to be commercially exploited through an experimental fishery. A recent policy on developing fisheries in South Africa emphasizes the importance of investigating the economic feasibility of a fishery as part of its management framework. The study reported here generated baseline information necessary in the design of the experimental fishery, giving guidelines as to which vessels, fishing gear and markets would be most feasible. The proposed fishery, gear and vessel type, fishing techniques and expected catch rates are described, the results of market research are outlined, and the cost of fishing is estimated. The potential business should consist of small and medium-sized vessels deploying unbaited pots attached to long lines. The longline pot fishery could be economically feasible, provided a 30 percent catch in 6600 pots/month is attained. Only existing, debt-free vessels should be used. The minimum catch per unit effort (CPUE) for various fishing operation scenarios was calculated to determine economic feasibility. This is an estimated minimum CPUE, based on assumptions that cannot be confirmed until the fishery starts. Furthermore, this economic analysis also needs to be assessed by stakeholders with experience of fishery operations , Rhodes Centenary issue of: South African Journal of Science.
- Full Text:
- Date Issued: 2004
- Authors: Oosthuizen, Ané
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6760 , http://hdl.handle.net/10962/d1007773
- Description: Octopus vulgaris was identified as a new marine resource to be commercially exploited through an experimental fishery. A recent policy on developing fisheries in South Africa emphasizes the importance of investigating the economic feasibility of a fishery as part of its management framework. The study reported here generated baseline information necessary in the design of the experimental fishery, giving guidelines as to which vessels, fishing gear and markets would be most feasible. The proposed fishery, gear and vessel type, fishing techniques and expected catch rates are described, the results of market research are outlined, and the cost of fishing is estimated. The potential business should consist of small and medium-sized vessels deploying unbaited pots attached to long lines. The longline pot fishery could be economically feasible, provided a 30 percent catch in 6600 pots/month is attained. Only existing, debt-free vessels should be used. The minimum catch per unit effort (CPUE) for various fishing operation scenarios was calculated to determine economic feasibility. This is an estimated minimum CPUE, based on assumptions that cannot be confirmed until the fishery starts. Furthermore, this economic analysis also needs to be assessed by stakeholders with experience of fishery operations , Rhodes Centenary issue of: South African Journal of Science.
- Full Text:
- Date Issued: 2004
Effects of substituents and solvents on the photochemical properties of zinc phthalocyanine complexes and their protonated derivatives
- Ogunsipe, Abimbola Olukayode, Nyokong, Tebello
- Authors: Ogunsipe, Abimbola Olukayode , Nyokong, Tebello
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6585 , http://hdl.handle.net/10962/d1004161
- Description: Zinc phthalocyanine derivatives containing various ring substituents and axial ligands were studied with respect to the effect of substituents on protonation. Aggregation resulted in failure of some of the ZnPc derivatives to protonate. In fact addition of protonating agents to aggregated ZnPc derivatives resulted in increase in aggregation followed by slow degradation. Axial ligands were lost on protonation. Photobleaching, fluorescence and singlet oxygen quantum yields of the protonated derivatives were compared with those of the unprotonated derivatives. In all cases protonation decreases the singlet oxygen and fluorescence quantum yields. However, photobleaching quantum yields decreased (i.e. stability increased) for the protonated derivatives except when axial ligands were present, where protonation resulted in decrease in stability.
- Full Text:
- Date Issued: 2004
- Authors: Ogunsipe, Abimbola Olukayode , Nyokong, Tebello
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6585 , http://hdl.handle.net/10962/d1004161
- Description: Zinc phthalocyanine derivatives containing various ring substituents and axial ligands were studied with respect to the effect of substituents on protonation. Aggregation resulted in failure of some of the ZnPc derivatives to protonate. In fact addition of protonating agents to aggregated ZnPc derivatives resulted in increase in aggregation followed by slow degradation. Axial ligands were lost on protonation. Photobleaching, fluorescence and singlet oxygen quantum yields of the protonated derivatives were compared with those of the unprotonated derivatives. In all cases protonation decreases the singlet oxygen and fluorescence quantum yields. However, photobleaching quantum yields decreased (i.e. stability increased) for the protonated derivatives except when axial ligands were present, where protonation resulted in decrease in stability.
- Full Text:
- Date Issued: 2004
Electrochemical and catalytic properties of chromium tetraaminophthalocyanine
- Obirai, Joe, Nyokong, Tebello
- Authors: Obirai, Joe , Nyokong, Tebello
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300310 , vital:57915 , xlink:href="https://doi.org/10.1016/j.jelechem.2004.06.026"
- Description: Chromium tetraaminophthalocyanine (CrIIITAPc) has been synthesized and its electrochemical and spectroelectrochemical properties reported. The first reduction and oxidation in this complex occur at the central metal, giving CrIITAPc and CrIVTAPc complexes, respectively, the latter having been observed for the first time. The CrIIITAPc species was polymerized onto glassy carbon (GCE) or indium tin oxide (ITO) electrodes and the polymer evolution confirmed by UV/Visible spectroscopy and by scanning electron microscopy. The polymers were employed for the catalytic oxidation of nitrite or nitric oxide, and the catalysis involved the CrIVTAPc−1 species.
- Full Text:
- Date Issued: 2004
- Authors: Obirai, Joe , Nyokong, Tebello
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300310 , vital:57915 , xlink:href="https://doi.org/10.1016/j.jelechem.2004.06.026"
- Description: Chromium tetraaminophthalocyanine (CrIIITAPc) has been synthesized and its electrochemical and spectroelectrochemical properties reported. The first reduction and oxidation in this complex occur at the central metal, giving CrIITAPc and CrIVTAPc complexes, respectively, the latter having been observed for the first time. The CrIIITAPc species was polymerized onto glassy carbon (GCE) or indium tin oxide (ITO) electrodes and the polymer evolution confirmed by UV/Visible spectroscopy and by scanning electron microscopy. The polymers were employed for the catalytic oxidation of nitrite or nitric oxide, and the catalysis involved the CrIVTAPc−1 species.
- Full Text:
- Date Issued: 2004
Electrochemical investigation of valve regulated lead acid batteries
- Authors: Ferg, Ernst Eduard
- Date: 2004
- Subjects: Lead acid batteries -- South Africa , Storage batteries -- South Africa , Electrochemistry -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech (Chemistry)
- Identifier: vital:10979 , http://hdl.handle.net/10948/228 , Lead acid batteries -- South Africa , Storage batteries -- South Africa , Electrochemistry -- South Africa
- Description: One of the technical advances made by the lead-acid battery industry in the field of portable power supply was the development of the valve regulated lead-acid battery (VRLA). This battery reduced the necessity for periodic servicing in terms of having to replenish the cells with distilled water. Further, this new type of battery can now be installed near sensitive electronic equipment without the danger of acid spill or dangerous fumes being emitted. In addition, longer service performance is achieved in terms of life cycle capacity, when compared to the conventional flooded type batteries. However, the new type of battery requires the manufacturing of high precision electrodes and components with low tolerances for error. In order for the manufacturers to produce such a premium product, a thorough understanding of the electrochemistry of the inner components is necessary. None of the South African lead-acid battery manufacturers are currently making VRLA batteries to supply a very competitive global market, where a large range of sizes and capabilities are available. In order to introduce the VRLA battery into such a competing market in South Africa, a niche area for its application was identified in order to establish the viability of manufacturing such a battery locally. This is done by integrating the VRLA concept into an existing battery, such as the miners cap lamp (MCL) battery. Its application is specific with well-defined performance criteria in a relatively large consumable market in the South African mining industry. The study looked at various components within a local manufacturing environment that required a better understanding and modification of the processes to build VRLA MCL batteries. This included a detailed study of the manufacturing processes of the positive electrode. The study involved the investigation of the types of grid alloys used, the type of electrode design, such as tubular or flat plate, the addition of redlead to the paste mixing process and subjecting the batteries to accelerated life cycle testing. A better understanding of the oxygen recombination cycle was also performed in order to evaluate the correct use of certain design criteria in the manufacturing process. This included the study of the pressure release valve and the type of positive electrode used. The study also looked at developing an inexpensive analytical technique to evaluate the porosity of cured and formed electrodes using a glycerol displacement method. The monitoring of the state of health (SoH) of VRLA batteries on a continuous basis is an important parameter in unique applications such as remote power supply. A device was developed to monitor the SoH of VRLA batteries on a continuous basis. The working principle of the device was tested on a MCL VRLA battery. With the development of other types of VRLA batteries for specific applications such as in stand-by power supplies, the monitoring device would then be integrated in the battery design.
- Full Text:
- Date Issued: 2004
- Authors: Ferg, Ernst Eduard
- Date: 2004
- Subjects: Lead acid batteries -- South Africa , Storage batteries -- South Africa , Electrochemistry -- South Africa
- Language: English
- Type: Thesis , Doctoral , DTech (Chemistry)
- Identifier: vital:10979 , http://hdl.handle.net/10948/228 , Lead acid batteries -- South Africa , Storage batteries -- South Africa , Electrochemistry -- South Africa
- Description: One of the technical advances made by the lead-acid battery industry in the field of portable power supply was the development of the valve regulated lead-acid battery (VRLA). This battery reduced the necessity for periodic servicing in terms of having to replenish the cells with distilled water. Further, this new type of battery can now be installed near sensitive electronic equipment without the danger of acid spill or dangerous fumes being emitted. In addition, longer service performance is achieved in terms of life cycle capacity, when compared to the conventional flooded type batteries. However, the new type of battery requires the manufacturing of high precision electrodes and components with low tolerances for error. In order for the manufacturers to produce such a premium product, a thorough understanding of the electrochemistry of the inner components is necessary. None of the South African lead-acid battery manufacturers are currently making VRLA batteries to supply a very competitive global market, where a large range of sizes and capabilities are available. In order to introduce the VRLA battery into such a competing market in South Africa, a niche area for its application was identified in order to establish the viability of manufacturing such a battery locally. This is done by integrating the VRLA concept into an existing battery, such as the miners cap lamp (MCL) battery. Its application is specific with well-defined performance criteria in a relatively large consumable market in the South African mining industry. The study looked at various components within a local manufacturing environment that required a better understanding and modification of the processes to build VRLA MCL batteries. This included a detailed study of the manufacturing processes of the positive electrode. The study involved the investigation of the types of grid alloys used, the type of electrode design, such as tubular or flat plate, the addition of redlead to the paste mixing process and subjecting the batteries to accelerated life cycle testing. A better understanding of the oxygen recombination cycle was also performed in order to evaluate the correct use of certain design criteria in the manufacturing process. This included the study of the pressure release valve and the type of positive electrode used. The study also looked at developing an inexpensive analytical technique to evaluate the porosity of cured and formed electrodes using a glycerol displacement method. The monitoring of the state of health (SoH) of VRLA batteries on a continuous basis is an important parameter in unique applications such as remote power supply. A device was developed to monitor the SoH of VRLA batteries on a continuous basis. The working principle of the device was tested on a MCL VRLA battery. With the development of other types of VRLA batteries for specific applications such as in stand-by power supplies, the monitoring device would then be integrated in the battery design.
- Full Text:
- Date Issued: 2004
Electrochemical studies of manganese tetraamminophthalocyanine monomer and polymer
- Obirai, Joseph, Nyokong, Tebello
- Authors: Obirai, Joseph , Nyokong, Tebello
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290330 , vital:56738 , xlink:href="https://doi.org/10.1016/j.electacta.2003.11.006"
- Description: Manganese tetraaminophthalocyanine (MnTAPc) has been synthesised. The cyclic voltammetry and spectroelectrochemistry of the complex have been examined. Spectroelectrochemistry has been used to confirm that the species synthesised in this work contains MnIII, giving (OH)MnIIITAPc. The oxidation and reduction couples obtained from cyclic voltammetry have been assigned to MnIVPc−/MnIVPc2− (couple I), MnIVPc2−/MnIIIPc2− (couple I′), MnIIIPc2−/MnIIPc2− (couple II) and MnIIPc2−/MnIIPc3− (couple III). Electropolymerization of the MnTAPc onto either the indium tin oxide or glassy carbon electrode results in the in the formation of a poly-MnTAPc. The poly-MnTAPc shows improved reversibility at low pH. The poly-MnTAPc electrode was employed to analyse glycine.
- Full Text:
- Date Issued: 2004
- Authors: Obirai, Joseph , Nyokong, Tebello
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290330 , vital:56738 , xlink:href="https://doi.org/10.1016/j.electacta.2003.11.006"
- Description: Manganese tetraaminophthalocyanine (MnTAPc) has been synthesised. The cyclic voltammetry and spectroelectrochemistry of the complex have been examined. Spectroelectrochemistry has been used to confirm that the species synthesised in this work contains MnIII, giving (OH)MnIIITAPc. The oxidation and reduction couples obtained from cyclic voltammetry have been assigned to MnIVPc−/MnIVPc2− (couple I), MnIVPc2−/MnIIIPc2− (couple I′), MnIIIPc2−/MnIIPc2− (couple II) and MnIIPc2−/MnIIPc3− (couple III). Electropolymerization of the MnTAPc onto either the indium tin oxide or glassy carbon electrode results in the in the formation of a poly-MnTAPc. The poly-MnTAPc shows improved reversibility at low pH. The poly-MnTAPc electrode was employed to analyse glycine.
- Full Text:
- Date Issued: 2004
Emerging patterns of abstraction in environmental education: A review of materials, methods and professional development perspectives
- O'Donoghue, Rob B, Russo, Vladimir
- Authors: O'Donoghue, Rob B , Russo, Vladimir
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373610 , vital:66707 , xlink:href="https://doi.org/10.1080/1350462042000258170"
- Description: The epistemic unconscious is the history of the field. And it is clear that, to secure some chance of really knowing what one is doing, one has to unfold what is inscribed in the various relations of implication in which the thinker and his thoughts are caught up, that is, the presuppositions he engages and the inclusions and exclusions he unwittingly performs. (Bourdieu, 2000, p. 99).
- Full Text:
- Date Issued: 2004
- Authors: O'Donoghue, Rob B , Russo, Vladimir
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373610 , vital:66707 , xlink:href="https://doi.org/10.1080/1350462042000258170"
- Description: The epistemic unconscious is the history of the field. And it is clear that, to secure some chance of really knowing what one is doing, one has to unfold what is inscribed in the various relations of implication in which the thinker and his thoughts are caught up, that is, the presuppositions he engages and the inclusions and exclusions he unwittingly performs. (Bourdieu, 2000, p. 99).
- Full Text:
- Date Issued: 2004
Emotions, social transformation and education
- Authors: Delport, Aletta Catherine
- Date: 2004
- Subjects: Educational sociology -- South Africa , Education -- Philosophy , Emotions (Philosophy)
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:11009 , http://hdl.handle.net/10948/318 , Educational sociology -- South Africa , Education -- Philosophy , Emotions (Philosophy)
- Description: This thesis addresses the topic of the education of the emotions in the context of a rapidly transforming South African society. It attempts to reconfigure the conceptual landscape in terms of which we think about rationality, social transformation and education, and contests the intellectual and instrumental prejudice in the currently dominant ways of thinking about education. It reclaims a sense of what it would be to think of education in terms of cultivating humanity, as a key to the profound transformation of the South African society. It argues that the emotions should be relocated in our conception of transformation and education, because without it, education will fail to assist South African society to transform into a society where most people are able to live improved quality lives. The thesis comprises three distinct parts. The first part consists of an account of a particular cognitive theory of the emotions, as developed by Martha Nussbaum in her book, Upheavals of thought. The Intelligence of Emotions (2001). This theory is then applied in Part 2 to examine the complexities of social transformation in South Africa at the more profound, personal level. This investigation is presented as a narrative and comprises the perspectives of the author, who is a white Afrikaner female, who grew up in South Africa in the heyday of Apartheid. In the final part, the concept of ‘education for transformation’ is discussed. It is argued that, in order for education to enhance the social transformation of South Africa, social transformation should be conceived according to a fundamental aspect of Rousseau’s political philosophy, namely that the ideal society comprises two reciprocally related spheres, the political and the personal sphere. Part 3 argues that ‘education for transformation’ should be conceived according to a conception of transformation, which acknowledges this double-layered texture. It further argues that ‘education for transformation’ should primarily be concerned with transformation at the personal level, since, according to Rousseau’s philosophy, this dimension is fundamental to ensuring the stability and legitimacy of the political order. However, built on the main insights of Part 2, this thesis also argues that personal transformation is only possible within a framework of rationality, which acknowledges the emotions as constitutive elements of rationality itself. Essentially, this thesis is about the conception of human being, which should be esteemed as the most fundamental and crucial element of successful social transformation.
- Full Text:
- Date Issued: 2004
- Authors: Delport, Aletta Catherine
- Date: 2004
- Subjects: Educational sociology -- South Africa , Education -- Philosophy , Emotions (Philosophy)
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:11009 , http://hdl.handle.net/10948/318 , Educational sociology -- South Africa , Education -- Philosophy , Emotions (Philosophy)
- Description: This thesis addresses the topic of the education of the emotions in the context of a rapidly transforming South African society. It attempts to reconfigure the conceptual landscape in terms of which we think about rationality, social transformation and education, and contests the intellectual and instrumental prejudice in the currently dominant ways of thinking about education. It reclaims a sense of what it would be to think of education in terms of cultivating humanity, as a key to the profound transformation of the South African society. It argues that the emotions should be relocated in our conception of transformation and education, because without it, education will fail to assist South African society to transform into a society where most people are able to live improved quality lives. The thesis comprises three distinct parts. The first part consists of an account of a particular cognitive theory of the emotions, as developed by Martha Nussbaum in her book, Upheavals of thought. The Intelligence of Emotions (2001). This theory is then applied in Part 2 to examine the complexities of social transformation in South Africa at the more profound, personal level. This investigation is presented as a narrative and comprises the perspectives of the author, who is a white Afrikaner female, who grew up in South Africa in the heyday of Apartheid. In the final part, the concept of ‘education for transformation’ is discussed. It is argued that, in order for education to enhance the social transformation of South Africa, social transformation should be conceived according to a fundamental aspect of Rousseau’s political philosophy, namely that the ideal society comprises two reciprocally related spheres, the political and the personal sphere. Part 3 argues that ‘education for transformation’ should be conceived according to a conception of transformation, which acknowledges this double-layered texture. It further argues that ‘education for transformation’ should primarily be concerned with transformation at the personal level, since, according to Rousseau’s philosophy, this dimension is fundamental to ensuring the stability and legitimacy of the political order. However, built on the main insights of Part 2, this thesis also argues that personal transformation is only possible within a framework of rationality, which acknowledges the emotions as constitutive elements of rationality itself. Essentially, this thesis is about the conception of human being, which should be esteemed as the most fundamental and crucial element of successful social transformation.
- Full Text:
- Date Issued: 2004
Endothermy in African Platypleurine Cicadas: the influence of body size and habitat (Hemiptera: Cicadidae)
- Sanborn, Allen F, Villet, Martin H, Phillips, Polly K F
- Authors: Sanborn, Allen F , Villet, Martin H , Phillips, Polly K F
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6925 , http://hdl.handle.net/10962/d1011912
- Description: The platypleurine cicadas have a wide distribution across Africa and southern Asia. We investigate endothermy as a thermoregulatory strategy in 11 South African species from five genera, with comparisons to the lone ectothermic platypleurine we found, in an attempt to ascertain any influence that habitat and/or body size have on the expression of endothermy in the platypleurine cicadas. Field measurements of body temperature (Tb) show that these animals regulate Tb through endogenous heat production. Heat production in the laboratory elevated Tb to the same range as in animals active in the field. Maximum Tb measured during calling activity when there was no access to solar radiation ranged from 13.2° to 22.3°C above ambient temperature in the five species measured. The mean Tb during activity without access to solar radiation did not differ from the mean Tb during diurnal activity. All platypleurines exhibit a unique behavior for cicadas while warming endogenously, a temperature- dependent telescoping pulsation of the abdomen that probably functions in ventilation. Platypleurines generally call from trunks and branches within the canopy and appear to rely on endothermy even when the sun is available to elevate Tb, in contrast to the facultative endothermy exhibited by New World endothermic species. The two exceptions to this generalization we found within the platypleurines are Platypleura wahlbergi and Albanycada albigera, which were the smallest species studied. The small size of P. wahlbergi appears to have altered their thermoregulatory strategy to one of facultative endothermy, whereby they use the sun when it is available to facilitate increases in Tb. Albanycada albigera is the only ectothermic platypleurine we found. The habitat and host plant association of A. albigera appear to have influenced the choice of ectothermy as a thermoregulatory strategy, as the species possesses the metabolic machinery to elevate to the Tb range observed in the endothermic species. Therefore, size and habitat appear to influence the expression of thermoregulatory strategies in African platypleurine cicadas.
- Full Text:
- Date Issued: 2004
- Authors: Sanborn, Allen F , Villet, Martin H , Phillips, Polly K F
- Date: 2004
- Language: English
- Type: text , Article
- Identifier: vital:6925 , http://hdl.handle.net/10962/d1011912
- Description: The platypleurine cicadas have a wide distribution across Africa and southern Asia. We investigate endothermy as a thermoregulatory strategy in 11 South African species from five genera, with comparisons to the lone ectothermic platypleurine we found, in an attempt to ascertain any influence that habitat and/or body size have on the expression of endothermy in the platypleurine cicadas. Field measurements of body temperature (Tb) show that these animals regulate Tb through endogenous heat production. Heat production in the laboratory elevated Tb to the same range as in animals active in the field. Maximum Tb measured during calling activity when there was no access to solar radiation ranged from 13.2° to 22.3°C above ambient temperature in the five species measured. The mean Tb during activity without access to solar radiation did not differ from the mean Tb during diurnal activity. All platypleurines exhibit a unique behavior for cicadas while warming endogenously, a temperature- dependent telescoping pulsation of the abdomen that probably functions in ventilation. Platypleurines generally call from trunks and branches within the canopy and appear to rely on endothermy even when the sun is available to elevate Tb, in contrast to the facultative endothermy exhibited by New World endothermic species. The two exceptions to this generalization we found within the platypleurines are Platypleura wahlbergi and Albanycada albigera, which were the smallest species studied. The small size of P. wahlbergi appears to have altered their thermoregulatory strategy to one of facultative endothermy, whereby they use the sun when it is available to facilitate increases in Tb. Albanycada albigera is the only ectothermic platypleurine we found. The habitat and host plant association of A. albigera appear to have influenced the choice of ectothermy as a thermoregulatory strategy, as the species possesses the metabolic machinery to elevate to the Tb range observed in the endothermic species. Therefore, size and habitat appear to influence the expression of thermoregulatory strategies in African platypleurine cicadas.
- Full Text:
- Date Issued: 2004
English language teaching and learning in the African preschool and educational achievement at grade 1: a case study
- Authors: Rendel, Philip Boudewijn
- Date: 2004
- Subjects: Education, Preschool -- South Africa -- Case studies , English language -- Study and teaching (Preschool) -- South Africa Case studies , English language -- Study and teaching (Elementary) -- South Africa -- Case studies , Children -- South Africa -- Language -- Case studies , Language acquisition -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2360 , http://hdl.handle.net/10962/d1002643 , Education, Preschool -- South Africa -- Case studies , English language -- Study and teaching (Preschool) -- South Africa Case studies , English language -- Study and teaching (Elementary) -- South Africa -- Case studies , Children -- South Africa -- Language -- Case studies , Language acquisition -- Case studies
- Description: In 1998, seventy per cent of children in South Africa failed and had to repeat the Grade 1 year. This is the result of a number of factors, among them academic and cultural readiness for school. Many primary schools in South Africa teach through English, a language that is not the home language of the majority of learners. Despite recent legislation aimed at improving preschool facilities and teacher capacity, there has been insufficient consideration of which languages are taught and how they should be taught to children before they arrive at Grade 1. This study sets out to explore whether there is a relational link between preschool English language teaching and learning and subsequent educational achievement at Grade 1. It also sketches out possible recommendations for improving the teaching and learning of English in the sample schools. The study does not attempt to enter the debate over choice of language of teaching and learning (LoLT). In this longitudinal case study, four children from two different preschools, (one mainly isiXhosa medium and one English medium), were observed in their classroom environments over a period of four months. The following year, the same children were observed in their respective Grade 1 classrooms, all of which were English medium either entirely or to a degree. The parents of all four children were interviewed in their home environment, as were their teachers. The study found that there is a significant communication gap between preschool teachers and Grade 1 teachers. This was combined with a self-confessed need amongst some teachers for increased training in teaching through English. Low motivation and limited professional experience in some cases contributed to a preschool language-learning environment that lacked many of the factors identified as being essential for a positive learning environment in early childhood There was in addition a clear bias in many sites towards universality of ECD prinCiples with little regard for the hegemony of Western pedagogy, particularly in the area of literacy acquisition. The study concludes by suggesting some ways in which this situation could be improved in order to enable preschool children to cope better with the demands of Grade 1.
- Full Text:
- Date Issued: 2004
- Authors: Rendel, Philip Boudewijn
- Date: 2004
- Subjects: Education, Preschool -- South Africa -- Case studies , English language -- Study and teaching (Preschool) -- South Africa Case studies , English language -- Study and teaching (Elementary) -- South Africa -- Case studies , Children -- South Africa -- Language -- Case studies , Language acquisition -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2360 , http://hdl.handle.net/10962/d1002643 , Education, Preschool -- South Africa -- Case studies , English language -- Study and teaching (Preschool) -- South Africa Case studies , English language -- Study and teaching (Elementary) -- South Africa -- Case studies , Children -- South Africa -- Language -- Case studies , Language acquisition -- Case studies
- Description: In 1998, seventy per cent of children in South Africa failed and had to repeat the Grade 1 year. This is the result of a number of factors, among them academic and cultural readiness for school. Many primary schools in South Africa teach through English, a language that is not the home language of the majority of learners. Despite recent legislation aimed at improving preschool facilities and teacher capacity, there has been insufficient consideration of which languages are taught and how they should be taught to children before they arrive at Grade 1. This study sets out to explore whether there is a relational link between preschool English language teaching and learning and subsequent educational achievement at Grade 1. It also sketches out possible recommendations for improving the teaching and learning of English in the sample schools. The study does not attempt to enter the debate over choice of language of teaching and learning (LoLT). In this longitudinal case study, four children from two different preschools, (one mainly isiXhosa medium and one English medium), were observed in their classroom environments over a period of four months. The following year, the same children were observed in their respective Grade 1 classrooms, all of which were English medium either entirely or to a degree. The parents of all four children were interviewed in their home environment, as were their teachers. The study found that there is a significant communication gap between preschool teachers and Grade 1 teachers. This was combined with a self-confessed need amongst some teachers for increased training in teaching through English. Low motivation and limited professional experience in some cases contributed to a preschool language-learning environment that lacked many of the factors identified as being essential for a positive learning environment in early childhood There was in addition a clear bias in many sites towards universality of ECD prinCiples with little regard for the hegemony of Western pedagogy, particularly in the area of literacy acquisition. The study concludes by suggesting some ways in which this situation could be improved in order to enable preschool children to cope better with the demands of Grade 1.
- Full Text:
- Date Issued: 2004
Environmental education research and social change: Southern African perspectives
- Authors: Lotz-Sisitka, Heila
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182709 , vital:43855 , xlink:href="https://doi.org/10.1080/1350462042000258143"
- Description: Environmental issues and risks in southern Africa have, like elsewhere in the world, their roots in the structures and orientations of modern societies. In modernist fashion, we draw on education and research to address socio-ecological concerns. In 1995 Eureta Janse van Rensburg, then Murray and Roberts Chair of Environmental Education at Rhodes University,1 undertook a study to identify environmental education research priorities, and through her study she provided a description of research in environmental education as a ‘landscape of shifting priorites’ (Janse van Rensburg, 1995). The papers in this journal offer a contemporary ‘snapshot’ of the landscape of environmental education research in southern Africa, illustrating a fresh range of ‘shifting priorities’.
- Full Text:
- Date Issued: 2004
- Authors: Lotz-Sisitka, Heila
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182709 , vital:43855 , xlink:href="https://doi.org/10.1080/1350462042000258143"
- Description: Environmental issues and risks in southern Africa have, like elsewhere in the world, their roots in the structures and orientations of modern societies. In modernist fashion, we draw on education and research to address socio-ecological concerns. In 1995 Eureta Janse van Rensburg, then Murray and Roberts Chair of Environmental Education at Rhodes University,1 undertook a study to identify environmental education research priorities, and through her study she provided a description of research in environmental education as a ‘landscape of shifting priorites’ (Janse van Rensburg, 1995). The papers in this journal offer a contemporary ‘snapshot’ of the landscape of environmental education research in southern Africa, illustrating a fresh range of ‘shifting priorities’.
- Full Text:
- Date Issued: 2004