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
Colonial photography in nineteenth century Grahamstown: an analysis of the Dr W.G. Atherstone Bequest
- Authors: Waters, Hywell George
- Date: 2000
- Subjects: Atherstone, W. G. (William Guybon), 1814-1898 Art and photography Photography -- Technique
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2426 , http://hdl.handle.net/10962/d1002222
- Description: The research for this degree comprises of a theoretical dissertationand a practicalcomponent of exhibited photographs. The theoretical research investigates the original photographic prints and glass-plate negatives taken betweenthe 1840's and 1890's, by the late Dr. W.G. Atherstone - an enthusiastic, Grahamstown amateur photographer. Dr W. G Atherstone's prints and negatives were examined by the author to deduce and establish his photographic abilities, his numerous techniques, diverse subject matter and the pictorialconstructionof his images. Selected works will be examined in order to interpret and illustrate his diverse interests and approaches towards photography. The selection of these photographs was determined by their pertinence to subject matter, and to the pictorial and historical considerations of the candidate. These issues are finally examined in relation to the candidates's own approach to photography today.
- Full Text:
- Date Issued: 2000
- Authors: Waters, Hywell George
- Date: 2000
- Subjects: Atherstone, W. G. (William Guybon), 1814-1898 Art and photography Photography -- Technique
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2426 , http://hdl.handle.net/10962/d1002222
- Description: The research for this degree comprises of a theoretical dissertationand a practicalcomponent of exhibited photographs. The theoretical research investigates the original photographic prints and glass-plate negatives taken betweenthe 1840's and 1890's, by the late Dr. W.G. Atherstone - an enthusiastic, Grahamstown amateur photographer. Dr W. G Atherstone's prints and negatives were examined by the author to deduce and establish his photographic abilities, his numerous techniques, diverse subject matter and the pictorialconstructionof his images. Selected works will be examined in order to interpret and illustrate his diverse interests and approaches towards photography. The selection of these photographs was determined by their pertinence to subject matter, and to the pictorial and historical considerations of the candidate. These issues are finally examined in relation to the candidates's own approach to photography today.
- Full Text:
- Date Issued: 2000
Comparative Spectroscopic and Electrochemical Properties of Bis (octakis (dodecylthio) naphthalocyaninato) europium (III) and Bis (tetra-tert-butylnaphthalocyaninato) europium (III) Complexes
- Nyokong, Tebello, Furuya, Fumio, Kobayashi, Nagao, Du, Daming, Liu, Wei, Jiang, Jianzhuang
- Authors: Nyokong, Tebello , Furuya, Fumio , Kobayashi, Nagao , Du, Daming , Liu, Wei , Jiang, Jianzhuang
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293174 , vital:57062 , xlink:href="https://doi.org/10.1021/ic990483b"
- Description: Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(SC12H25)8]2, 1} and bis(tetra-tert-butyl-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(t-Bu)4]2, 2} have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3·H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV−visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2 → 2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = −0.28 V (for 2) and −0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = −0.61, −1.64, −1.97, and −2.42 V, and for 1 they were observed at E1/2 = −0.62, −1.60, −1.86, and −2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared.
- Full Text:
- Date Issued: 2000
- Authors: Nyokong, Tebello , Furuya, Fumio , Kobayashi, Nagao , Du, Daming , Liu, Wei , Jiang, Jianzhuang
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293174 , vital:57062 , xlink:href="https://doi.org/10.1021/ic990483b"
- Description: Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(SC12H25)8]2, 1} and bis(tetra-tert-butyl-2,3-naphthalocyaninato)europium(III) {Eu[2,3-Nc(t-Bu)4]2, 2} have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3·H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV−visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2 → 2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = −0.28 V (for 2) and −0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = −0.61, −1.64, −1.97, and −2.42 V, and for 1 they were observed at E1/2 = −0.62, −1.60, −1.86, and −2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared.
- Full Text:
- Date Issued: 2000
Comparative study on the biological performance of progenies of Western Sanga x Afrikaner and Bonsmara cattle in the sourish mixed bushveld of the North West Province
- Authors: Moraka, Joseph Ntlhoki
- Date: 2000
- Subjects: Beef cattle breeds , Bonsmara cattle , Afrikaner cattle
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10947 , http://hdl.handle.net/10948/21 , Beef cattle breeds , Bonsmara cattle , Afrikaner cattle
- Description: The study compares the biological performance of progenies of the Afrikaner x Western Sanga crossbred (small frame) and the Bonsmara (medium frame) cattle on the following traits: calving and growth rates as well as mortalities. The study was conducted in the Sourish Mixed Bushveld of the North West province. The objective was to identify a lowcare cattle breed, which can withstand unfavourable conditions under which most farmers in the North West Province operate. The results of this study indicated that, under good management, the Bonsmara cattle have higher growth rates compared to the Sanga cattle. There were statistical differences with regards to birth, pre-wean and wean masses, (P< 0.0001). Sanga cattle however were able to maintain higher calving rates under all varying conditions (Bonsmara 77% average and Sanga 84% average). The Sanga, due to its lower nutritional requirements, on average requires 15% less of the surface area required by the Bonsmara. Sanga cattle also returned better yields in terms of kilogram weaned calf per LSU and per hectare. With regard to herd mortalities, there was no significant difference (P = 0.03329).
- Full Text:
- Date Issued: 2000
- Authors: Moraka, Joseph Ntlhoki
- Date: 2000
- Subjects: Beef cattle breeds , Bonsmara cattle , Afrikaner cattle
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10947 , http://hdl.handle.net/10948/21 , Beef cattle breeds , Bonsmara cattle , Afrikaner cattle
- Description: The study compares the biological performance of progenies of the Afrikaner x Western Sanga crossbred (small frame) and the Bonsmara (medium frame) cattle on the following traits: calving and growth rates as well as mortalities. The study was conducted in the Sourish Mixed Bushveld of the North West province. The objective was to identify a lowcare cattle breed, which can withstand unfavourable conditions under which most farmers in the North West Province operate. The results of this study indicated that, under good management, the Bonsmara cattle have higher growth rates compared to the Sanga cattle. There were statistical differences with regards to birth, pre-wean and wean masses, (P< 0.0001). Sanga cattle however were able to maintain higher calving rates under all varying conditions (Bonsmara 77% average and Sanga 84% average). The Sanga, due to its lower nutritional requirements, on average requires 15% less of the surface area required by the Bonsmara. Sanga cattle also returned better yields in terms of kilogram weaned calf per LSU and per hectare. With regard to herd mortalities, there was no significant difference (P = 0.03329).
- Full Text:
- Date Issued: 2000
Comparison of plant diversity in protected and communal lands in the Bushbuckridge lowveld savanna, South Africa
- Authors: Shackleton, Charlie M
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181885 , vital:43777 , xlink:href="https://doi.org/10.1016/S0006-3207(00)00001-X"
- Description: Patterns of higher plant species richness and beta diversity were assessed using standard Modified-Whittaker plots in relation to land use, slope position and mean annual rainfall across a rainfall gradient in the savanna areas of the Bushbuckridge lowveld, South Africa. In particular, comparison of communal areas with adjacent protected areas was important in showing the impacts of potential changes in land use within an overarching catchment management plan. Although most of the protected areas considered preservation of biodiversity as their primary goal, they were characterised by significantly fewer plant species than the adjacent, highly utilised, communal lands, at both the plot and point scale. Slope position also had a significant effect on plant species richness, with eutrophic bottomlands having c. 30% more species than the dystrophic toplands. This adds weight to the need for greater public awareness for the judicious use and management of the sensitive bottomlands, which fringe the primary drainage lines that are vital for sustained supplies of good quality surface water in this semi-arid environment. The total number of species increased with increasing mean annual rainfall across the rainfall gradient. This suggests that, if the catchment management plan aims to identify additional areas for conservation, the higher rainfall areas should be the first to be assessed. Species turnover was greater along the rainfall gradient than the catenal gradient between toplands and bottomlands.
- Full Text:
- Date Issued: 2000
- Authors: Shackleton, Charlie M
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181885 , vital:43777 , xlink:href="https://doi.org/10.1016/S0006-3207(00)00001-X"
- Description: Patterns of higher plant species richness and beta diversity were assessed using standard Modified-Whittaker plots in relation to land use, slope position and mean annual rainfall across a rainfall gradient in the savanna areas of the Bushbuckridge lowveld, South Africa. In particular, comparison of communal areas with adjacent protected areas was important in showing the impacts of potential changes in land use within an overarching catchment management plan. Although most of the protected areas considered preservation of biodiversity as their primary goal, they were characterised by significantly fewer plant species than the adjacent, highly utilised, communal lands, at both the plot and point scale. Slope position also had a significant effect on plant species richness, with eutrophic bottomlands having c. 30% more species than the dystrophic toplands. This adds weight to the need for greater public awareness for the judicious use and management of the sensitive bottomlands, which fringe the primary drainage lines that are vital for sustained supplies of good quality surface water in this semi-arid environment. The total number of species increased with increasing mean annual rainfall across the rainfall gradient. This suggests that, if the catchment management plan aims to identify additional areas for conservation, the higher rainfall areas should be the first to be assessed. Species turnover was greater along the rainfall gradient than the catenal gradient between toplands and bottomlands.
- Full Text:
- Date Issued: 2000
Computers in science teaching: a reality or dream; The role of computers in effective science education: a case of using a computer to teach colour mixing; Career oriented science education for the next millennium
- Authors: Nadarajah, Kumaravel
- Date: 2000
- Subjects: Science -- Study and teaching Computer-assisted instruction Education -- Data processing
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1460 , http://hdl.handle.net/10962/d1003341
- Description: Science education in South Africa is not improving much. Many science educators do not have appropriate science qualifications. Majority of the learners have limited facilities to learn science. In this dilemma the move to OBE may result in further substantial deterioration of science education. A possible way out is to use computers in science education to facilitate the learning process. This study was designed to investigate how computers contribute to learners’ skills development in a physics course. A series of interactive computer simulations of colour mixing and a number of closely related traditional practical activities are aimed to promote learners’ understanding of colour. It was concluded that while computer environments have greater potentialas learning tools, they also limit interactions in significant ways.
- Full Text:
- Date Issued: 2000
- Authors: Nadarajah, Kumaravel
- Date: 2000
- Subjects: Science -- Study and teaching Computer-assisted instruction Education -- Data processing
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1460 , http://hdl.handle.net/10962/d1003341
- Description: Science education in South Africa is not improving much. Many science educators do not have appropriate science qualifications. Majority of the learners have limited facilities to learn science. In this dilemma the move to OBE may result in further substantial deterioration of science education. A possible way out is to use computers in science education to facilitate the learning process. This study was designed to investigate how computers contribute to learners’ skills development in a physics course. A series of interactive computer simulations of colour mixing and a number of closely related traditional practical activities are aimed to promote learners’ understanding of colour. It was concluded that while computer environments have greater potentialas learning tools, they also limit interactions in significant ways.
- Full Text:
- Date Issued: 2000
Constitutional frameworks and democratization in Africa since independence
- Authors: Neirynck, Karim
- Date: 2000
- Subjects: Democracy -- Africa , Constitutions -- Africa , Africa -- Politics and government -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2816 , http://hdl.handle.net/10962/d1003026 , Democracy -- Africa , Constitutions -- Africa , Africa -- Politics and government -- 1960-
- Description: The subject of this thesis is international studies, specifically a study of constitutional frameworks in Africa in the second half of the 20th century, focussing on a statistical correlation between constitutional frameworks, party systems, electoral systems and the Index of Democracy. The struggle to consolidate new democracies - especially those in Eastern Europe, Latin America and Asia - has given rise to a wide-ranging debate about the hard choices concerning democratic political institutions and political markets. According to Stepan and Skach " this literature has produced provocative hypotheses about the effects of institutions on democracy" (Stepan and Skach, 1993 : 1). It forms part of the' new institutionalism I literature in comparative politics that'holds as a premise that political democracy depends not only on economic and social conditions but also on the design of political institutions (Koelble, 1995 : 231-243). " One fundamental political-institutional question that has only received serious scholarly attention concerns the impact of different constitutional frameworks on democratic consolidation. Although the topic has been increasingly debated and discussed, little systematic cross-regional evidence [especially for our field of research: Africa] has been brought to bear on it " (Stepan and Skach, 1993 : 1-2). So far, only the book"on regime transitions in Africa written by Bratton and Van De Walle seeks to fill this empirical gap (Bratton and Van De Walle, 1997, preface xiii). In this thesis, we paid particular attention to the dichotomy between (pure) parliamentarism and (pure) presidentialism. Each type has fundamental characteristics, and for the purposes of classification these characteristics are necessary and sufficient. It was not our purpose to weigh the benefits and drawbacks of parliamentarism and presidentialism. Our intention was to report and analyse different sources of data, and we based our case exclusively on statistic correlatiohs between regime type and the record of democratic success and failure. We collected a data set about constitutional frameworks (matrix1), democracy indices (matrix2), party systems (matrix3) and election systems (matrix4). The basis for matrix 1 was the constitutions of the African countries (over time) and relevant literature. The basis for matrix 2 was the annual Freedom House ratings made by Raymond D. Gastil and others. The basis for matrix 3 and 4 was relevant literature. Once these matrices had been composed, we compared them and calculated statistic correlations. This long-dyration model allowed us to estimate whether African constitutional frameworks, party systems and electoral systems exhibit positive or negative correlation with the index of democracy.
- Full Text:
- Date Issued: 2000
- Authors: Neirynck, Karim
- Date: 2000
- Subjects: Democracy -- Africa , Constitutions -- Africa , Africa -- Politics and government -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2816 , http://hdl.handle.net/10962/d1003026 , Democracy -- Africa , Constitutions -- Africa , Africa -- Politics and government -- 1960-
- Description: The subject of this thesis is international studies, specifically a study of constitutional frameworks in Africa in the second half of the 20th century, focussing on a statistical correlation between constitutional frameworks, party systems, electoral systems and the Index of Democracy. The struggle to consolidate new democracies - especially those in Eastern Europe, Latin America and Asia - has given rise to a wide-ranging debate about the hard choices concerning democratic political institutions and political markets. According to Stepan and Skach " this literature has produced provocative hypotheses about the effects of institutions on democracy" (Stepan and Skach, 1993 : 1). It forms part of the' new institutionalism I literature in comparative politics that'holds as a premise that political democracy depends not only on economic and social conditions but also on the design of political institutions (Koelble, 1995 : 231-243). " One fundamental political-institutional question that has only received serious scholarly attention concerns the impact of different constitutional frameworks on democratic consolidation. Although the topic has been increasingly debated and discussed, little systematic cross-regional evidence [especially for our field of research: Africa] has been brought to bear on it " (Stepan and Skach, 1993 : 1-2). So far, only the book"on regime transitions in Africa written by Bratton and Van De Walle seeks to fill this empirical gap (Bratton and Van De Walle, 1997, preface xiii). In this thesis, we paid particular attention to the dichotomy between (pure) parliamentarism and (pure) presidentialism. Each type has fundamental characteristics, and for the purposes of classification these characteristics are necessary and sufficient. It was not our purpose to weigh the benefits and drawbacks of parliamentarism and presidentialism. Our intention was to report and analyse different sources of data, and we based our case exclusively on statistic correlatiohs between regime type and the record of democratic success and failure. We collected a data set about constitutional frameworks (matrix1), democracy indices (matrix2), party systems (matrix3) and election systems (matrix4). The basis for matrix 1 was the constitutions of the African countries (over time) and relevant literature. The basis for matrix 2 was the annual Freedom House ratings made by Raymond D. Gastil and others. The basis for matrix 3 and 4 was relevant literature. Once these matrices had been composed, we compared them and calculated statistic correlations. This long-dyration model allowed us to estimate whether African constitutional frameworks, party systems and electoral systems exhibit positive or negative correlation with the index of democracy.
- Full Text:
- Date Issued: 2000
Criteria social workers employ in making child custody recommendations
- Authors: Froneman, Anna Petronella
- Date: 2000
- Subjects: Custody of children -- South Africa Social work with children -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:696 , http://hdl.handle.net/10962/d1006414
- Description: During this study, an attempt was made to investigate the process employed by social workers in conducting child custody evaluations and making decisions related to the process, as well as to provide insight into which criteria are currently being used. The goal was to explore the perceived usefulness of these criteria from the perspective of social work, and to assess the adequacy of the requirements of the custody report in reflecting the above process and decision-making. In order to meet this goal, literature and empirical studies were conducted. The literature study focuses on the history of child custody matters, custody decision-making and legislation, types of custody arrangements, criteria social workers employ in making child custody recommendations, evaluator bias and custody evaluation reports. During the empirical research phase, a non-probability purposive sampling procedure was adopted. Five family counsellors from the office of the family advocate serving the Eastern Cape were selected. After an interview schedule was compiled to cover certain topics and their sequence, semi-structured interviews were conducted with the family counsellors. In order to compare the criteria stated in the interviews with the criteria applied in the custody reports, three cases from each family counsellor were selected and the final custody report and recommendation were studied. This study has revealed the following: some of the family counsellors experience proqlems with the process of custody evaluations; certain aspects regarding the process are not in line with some ofthe literature; some of the criteria used by the family counsellors are not evident in the custody reports and are not discussed in detail; a lack of training exists for the family counsellors; and the family counsellors experience some form of bias. Finally, based on the research findings, recommendations were made regarding the process of custody evaluation, the criteria social workers employ when conducting child custody evaluations, training and bias of family counsellors, the role of the family advocate and possible future research.
- Full Text:
- Date Issued: 2000
- Authors: Froneman, Anna Petronella
- Date: 2000
- Subjects: Custody of children -- South Africa Social work with children -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:696 , http://hdl.handle.net/10962/d1006414
- Description: During this study, an attempt was made to investigate the process employed by social workers in conducting child custody evaluations and making decisions related to the process, as well as to provide insight into which criteria are currently being used. The goal was to explore the perceived usefulness of these criteria from the perspective of social work, and to assess the adequacy of the requirements of the custody report in reflecting the above process and decision-making. In order to meet this goal, literature and empirical studies were conducted. The literature study focuses on the history of child custody matters, custody decision-making and legislation, types of custody arrangements, criteria social workers employ in making child custody recommendations, evaluator bias and custody evaluation reports. During the empirical research phase, a non-probability purposive sampling procedure was adopted. Five family counsellors from the office of the family advocate serving the Eastern Cape were selected. After an interview schedule was compiled to cover certain topics and their sequence, semi-structured interviews were conducted with the family counsellors. In order to compare the criteria stated in the interviews with the criteria applied in the custody reports, three cases from each family counsellor were selected and the final custody report and recommendation were studied. This study has revealed the following: some of the family counsellors experience proqlems with the process of custody evaluations; certain aspects regarding the process are not in line with some ofthe literature; some of the criteria used by the family counsellors are not evident in the custody reports and are not discussed in detail; a lack of training exists for the family counsellors; and the family counsellors experience some form of bias. Finally, based on the research findings, recommendations were made regarding the process of custody evaluation, the criteria social workers employ when conducting child custody evaluations, training and bias of family counsellors, the role of the family advocate and possible future research.
- Full Text:
- Date Issued: 2000
Cuba's revolutionist and anti-imperialist foreign policy in Southern Africa: the case of Angola and Namibia
- Authors: Othieno, Timothy
- Date: 2000
- Subjects: Cuba -- Foreign Relations -- Africa, Southern , Cuba -- Dependency on foreign countries -- History , Cuba -- Foreign relations -- Angola , Cuba -- Foreign relations -- Namibia , Cuba -- Politics and government
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2819 , http://hdl.handle.net/10962/d1003029 , Cuba -- Foreign Relations -- Africa, Southern , Cuba -- Dependency on foreign countries -- History , Cuba -- Foreign relations -- Angola , Cuba -- Foreign relations -- Namibia , Cuba -- Politics and government
- Description: This study examines Cuba’s role in the two southern African countries of Angola and Namibia during the Cold War period. It argues that Cuba’s ideological motivations have been embodied in the mutually reinforcing concepts of proletarian internationalism and anti-imperialism. These conceptual perspectives constitute some of the central variables that influence Cuba’s foreign policy behaviour in international relations. It is within this context that one can understand Cuba’s involvement in Southern Africa. This study also attempts to explain that Cuban foreign policy towards Africa was based on two complementary and contextual objectives namely, promoting nationalism at home and nurturing revolutionary Marxist-Leninist governments, as well as supporting anti-colonial and anti-imperialist movements abroad. For the purpose of achieving these foreign policy objectives, Cuba not only engaged in state-to-state relations with Angola and Namibia; but had cordial relations with the rest of the continent and in particular Southern Africa, which also became a direct military testing ground for Cuba’s commitment to an anti-colonial and anti-imperialist revolutionary stance. Furthermore, the thesis shows that Cuba’s relentless hatred of imperialism is rooted in its historical relationship with the United States because from the turn of the century till 1958, the Americans interfered in Cuba’s internal affairs by supporting corrupt administrations and exploited the country. These practices by the United States laid the foundation for Cuba’s anti-colonialism and antiimperialism abroad. Ultimately, this thesis shows that Cuban involvement in Angola and Namibia can be conceptualised within these contexts (anti-imperialism, anti-colonialism, proletarian internationalism and revolutionary Marxism-Leninism). The role of Cuban nationalism in the realisation of these objectives and ideals, as well as its role in perpetuating and consolidating her foreign policy is assessed in this study. This nationalism and ideals of internationalism constitutes the central idea in the Cuban revolution. Finally, this thesis asserts that Cuban motives for getting involved in the politics of Southern Africa were not motivated by economic or imperialistic reasons. Rather, the historical similarity and colonial experiences between Africa and Cuba were some of the central causal factors.
- Full Text:
- Date Issued: 2000
- Authors: Othieno, Timothy
- Date: 2000
- Subjects: Cuba -- Foreign Relations -- Africa, Southern , Cuba -- Dependency on foreign countries -- History , Cuba -- Foreign relations -- Angola , Cuba -- Foreign relations -- Namibia , Cuba -- Politics and government
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2819 , http://hdl.handle.net/10962/d1003029 , Cuba -- Foreign Relations -- Africa, Southern , Cuba -- Dependency on foreign countries -- History , Cuba -- Foreign relations -- Angola , Cuba -- Foreign relations -- Namibia , Cuba -- Politics and government
- Description: This study examines Cuba’s role in the two southern African countries of Angola and Namibia during the Cold War period. It argues that Cuba’s ideological motivations have been embodied in the mutually reinforcing concepts of proletarian internationalism and anti-imperialism. These conceptual perspectives constitute some of the central variables that influence Cuba’s foreign policy behaviour in international relations. It is within this context that one can understand Cuba’s involvement in Southern Africa. This study also attempts to explain that Cuban foreign policy towards Africa was based on two complementary and contextual objectives namely, promoting nationalism at home and nurturing revolutionary Marxist-Leninist governments, as well as supporting anti-colonial and anti-imperialist movements abroad. For the purpose of achieving these foreign policy objectives, Cuba not only engaged in state-to-state relations with Angola and Namibia; but had cordial relations with the rest of the continent and in particular Southern Africa, which also became a direct military testing ground for Cuba’s commitment to an anti-colonial and anti-imperialist revolutionary stance. Furthermore, the thesis shows that Cuba’s relentless hatred of imperialism is rooted in its historical relationship with the United States because from the turn of the century till 1958, the Americans interfered in Cuba’s internal affairs by supporting corrupt administrations and exploited the country. These practices by the United States laid the foundation for Cuba’s anti-colonialism and antiimperialism abroad. Ultimately, this thesis shows that Cuban involvement in Angola and Namibia can be conceptualised within these contexts (anti-imperialism, anti-colonialism, proletarian internationalism and revolutionary Marxism-Leninism). The role of Cuban nationalism in the realisation of these objectives and ideals, as well as its role in perpetuating and consolidating her foreign policy is assessed in this study. This nationalism and ideals of internationalism constitutes the central idea in the Cuban revolution. Finally, this thesis asserts that Cuban motives for getting involved in the politics of Southern Africa were not motivated by economic or imperialistic reasons. Rather, the historical similarity and colonial experiences between Africa and Cuba were some of the central causal factors.
- Full Text:
- Date Issued: 2000
Cumulative mild head injury in contact sport: a comparison of the cognitive profiles of rugby players and non-contact sport controls with normative data
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Date Issued: 2000
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Date Issued: 2000
Cyanide-induced free radical production and lipid peroxidation in rat brain homogenate is reduced by aspirin
- Daya, Santylal, Walker, Roderick B, Anoopkumar-Dukie, Shailendra
- Authors: Daya, Santylal , Walker, Roderick B , Anoopkumar-Dukie, Shailendra
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184346 , vital:44210 , xlink:href="https://doi.org/10.1007/BF02674529"
- Description: The neuroprotective properties of aspirin were investigated using cyanide-induced neurotoxicity as model. Cyanide, a known neurotoxic agent significantly increased lipid peroxidation and superoxide anion levels in rat brain homogenate in a concentration-dependent manner (0.25–1.0 mM). When homogenate, containing 1.0 mM KCN was cotreated with aspirin (1.0 mM) there was a significant decrease in lipid peroxidation. Aspirin (0.5 mM and 1.0 mM) also significantly reduced KCN-induced superoxide anion generation. The results of the present report therefore indicate a neuroprotective role for aspirin.
- Full Text:
- Date Issued: 2000
- Authors: Daya, Santylal , Walker, Roderick B , Anoopkumar-Dukie, Shailendra
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184346 , vital:44210 , xlink:href="https://doi.org/10.1007/BF02674529"
- Description: The neuroprotective properties of aspirin were investigated using cyanide-induced neurotoxicity as model. Cyanide, a known neurotoxic agent significantly increased lipid peroxidation and superoxide anion levels in rat brain homogenate in a concentration-dependent manner (0.25–1.0 mM). When homogenate, containing 1.0 mM KCN was cotreated with aspirin (1.0 mM) there was a significant decrease in lipid peroxidation. Aspirin (0.5 mM and 1.0 mM) also significantly reduced KCN-induced superoxide anion generation. The results of the present report therefore indicate a neuroprotective role for aspirin.
- Full Text:
- Date Issued: 2000
Desert
- Authors: Harper, Sean Julian
- Date: 2000
- Subjects: Rawls, John, 1921-2002 , Rawls, John, 1921-2002 Theory of justice , Ethics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2710 , http://hdl.handle.net/10962/d1002840 , Rawls, John, 1921-2002 , Rawls, John, 1921-2002 Theory of justice , Ethics
- Description: This thesis examines the idea of desert as expounded in the work of John Rawls, and some of the implications of this conception of desert for moral and political philosophy. In this work, I analyse a series of arguments against retaining this particular conception of desert.I argue that none of these arguments sufficiently diminishes the force of Rawls’ argument for desert, while many of them do state, and I argue that they are correct in doing so, that this conception of desert is dangerous for political or moral philosophy to maintain. I argue that the moral, political and legal implications of accepting this account of desert severely undermine various institutions of differential treatment, and indeed, moral assessment. I regard it as obvious that societies must, on occasion, treat members of those societies differently, for moral, as well as practical reasons. The Rawlsian account of desert, and the account of responsibility on which it rests, however, will endanger the legitimacy of such procedures. I argue further that the Rawlsian account of desert requires that differences in wealth, and inheritance of wealth, influence and privilege be diminished, if not abolished, if we are to talk of any form of desert meaningfully. I argue that this is a strength of Rawls’ account, and further that any account of desert that is true to the philosophical tradition of the concept will require similar steps to be taken. The primary aim of this thesis is to show that Rawls’ arguments against desert are serious ones, both in terms of strength and scope, and that they must be addressed. I intend to show that these arguments are founded on strong moral intuitions, and that it is plausible that these intuitions may need revision. Finally,I intend to show that desert is an important moral and political concept, and that the disciplines of moral and political philosophy will be impoverished by the absence this concept. This absence, I will argue, is a natural consequence of the acceptance of the Rawlsian arguments.
- Full Text:
- Date Issued: 2000
- Authors: Harper, Sean Julian
- Date: 2000
- Subjects: Rawls, John, 1921-2002 , Rawls, John, 1921-2002 Theory of justice , Ethics
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2710 , http://hdl.handle.net/10962/d1002840 , Rawls, John, 1921-2002 , Rawls, John, 1921-2002 Theory of justice , Ethics
- Description: This thesis examines the idea of desert as expounded in the work of John Rawls, and some of the implications of this conception of desert for moral and political philosophy. In this work, I analyse a series of arguments against retaining this particular conception of desert.I argue that none of these arguments sufficiently diminishes the force of Rawls’ argument for desert, while many of them do state, and I argue that they are correct in doing so, that this conception of desert is dangerous for political or moral philosophy to maintain. I argue that the moral, political and legal implications of accepting this account of desert severely undermine various institutions of differential treatment, and indeed, moral assessment. I regard it as obvious that societies must, on occasion, treat members of those societies differently, for moral, as well as practical reasons. The Rawlsian account of desert, and the account of responsibility on which it rests, however, will endanger the legitimacy of such procedures. I argue further that the Rawlsian account of desert requires that differences in wealth, and inheritance of wealth, influence and privilege be diminished, if not abolished, if we are to talk of any form of desert meaningfully. I argue that this is a strength of Rawls’ account, and further that any account of desert that is true to the philosophical tradition of the concept will require similar steps to be taken. The primary aim of this thesis is to show that Rawls’ arguments against desert are serious ones, both in terms of strength and scope, and that they must be addressed. I intend to show that these arguments are founded on strong moral intuitions, and that it is plausible that these intuitions may need revision. Finally,I intend to show that desert is an important moral and political concept, and that the disciplines of moral and political philosophy will be impoverished by the absence this concept. This absence, I will argue, is a natural consequence of the acceptance of the Rawlsian arguments.
- Full Text:
- Date Issued: 2000
Designing and implementing a virtual reality interaction framework
- Authors: Rorke, Michael
- Date: 2000
- Subjects: Virtual reality , Computer simulation , Human-computer interaction , Computer graphics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4623 , http://hdl.handle.net/10962/d1006491 , Virtual reality , Computer simulation , Human-computer interaction , Computer graphics
- Description: Virtual Reality offers the possibility for humans to interact in a more natural way with the computer and its applications. Currently, Virtual Reality is used mainly in the field of visualisation where 3D graphics allow users to more easily view complex sets of data or structures. The field of interaction in Virtual Reality has been largely neglected due mainly to problems with input devices and equipment costs. Recent research has aimed to overcome these interaction problems, thereby creating a usable interaction platform for Virtual Reality. This thesis presents a background into the field of interaction in Virtual Reality. It goes on to propose a generic framework for the implementation of common interaction techniques into a homogeneous application development environment. This framework adds a new layer to the standard Virtual Reality toolkit – the interaction abstraction layer, or interactor layer. This separation is in line with current HCI practices. The interactor layer is further divided into specific sections – input component, interaction component, system component, intermediaries, entities and widgets. Each of these performs a specific function, with clearly defined interfaces between the different components to promote easy objectoriented implementation of the framework. The validity of the framework is shown in comparison with accepted taxonomies in the area of Virtual Reality interaction. Thus demonstrating that the framework covers all the relevant factors involved in the field. Furthermore, the thesis describes an implementation of this framework. The implementation was completed using the Rhodes University CoRgi Virtual Reality toolkit. Several postgraduate students in the Rhodes University Computer Science Department utilised the framework implementation to develop a set of case studies. These case studies demonstrate the practical use of the framework to create useful Virtual Reality applications, as well as demonstrating the generic nature of the framework and its extensibility to be able to handle new interaction techniques. Finally, the generic nature of the framework is further demonstrated by moving it from the standard CoRgi Virtual Reality toolkit, to a distributed version of this toolkit. The distributed implementation of the framework utilises the Common Object Request Broker Architecture (CORBA) to implement the distribution of the objects in the system. Using this distributed implementation, we are able to ascertain that CORBA is useful in the field of distributed real-time Virtual Reality, even taking into account the extra overhead introduced by the additional abstraction layer. We conclude from this thesis that it is important to abstract the interaction layer from the other layers of a Virtual Reality toolkit in order to provide a consistent interface to developers. We have shown that our framework is implementable and useful in the field, making it easier for developers to include interaction in their Virtual Reality applications. Our framework is able to handle all the current aspects of interaction in Virtual Reality, as well as being general enough to implement future interaction techniques. The framework is also applicable to different Virtual Reality toolkits and development platforms, making it ideal for developing general, cross-platform interactive Virtual Reality applications.
- Full Text:
- Date Issued: 2000
- Authors: Rorke, Michael
- Date: 2000
- Subjects: Virtual reality , Computer simulation , Human-computer interaction , Computer graphics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4623 , http://hdl.handle.net/10962/d1006491 , Virtual reality , Computer simulation , Human-computer interaction , Computer graphics
- Description: Virtual Reality offers the possibility for humans to interact in a more natural way with the computer and its applications. Currently, Virtual Reality is used mainly in the field of visualisation where 3D graphics allow users to more easily view complex sets of data or structures. The field of interaction in Virtual Reality has been largely neglected due mainly to problems with input devices and equipment costs. Recent research has aimed to overcome these interaction problems, thereby creating a usable interaction platform for Virtual Reality. This thesis presents a background into the field of interaction in Virtual Reality. It goes on to propose a generic framework for the implementation of common interaction techniques into a homogeneous application development environment. This framework adds a new layer to the standard Virtual Reality toolkit – the interaction abstraction layer, or interactor layer. This separation is in line with current HCI practices. The interactor layer is further divided into specific sections – input component, interaction component, system component, intermediaries, entities and widgets. Each of these performs a specific function, with clearly defined interfaces between the different components to promote easy objectoriented implementation of the framework. The validity of the framework is shown in comparison with accepted taxonomies in the area of Virtual Reality interaction. Thus demonstrating that the framework covers all the relevant factors involved in the field. Furthermore, the thesis describes an implementation of this framework. The implementation was completed using the Rhodes University CoRgi Virtual Reality toolkit. Several postgraduate students in the Rhodes University Computer Science Department utilised the framework implementation to develop a set of case studies. These case studies demonstrate the practical use of the framework to create useful Virtual Reality applications, as well as demonstrating the generic nature of the framework and its extensibility to be able to handle new interaction techniques. Finally, the generic nature of the framework is further demonstrated by moving it from the standard CoRgi Virtual Reality toolkit, to a distributed version of this toolkit. The distributed implementation of the framework utilises the Common Object Request Broker Architecture (CORBA) to implement the distribution of the objects in the system. Using this distributed implementation, we are able to ascertain that CORBA is useful in the field of distributed real-time Virtual Reality, even taking into account the extra overhead introduced by the additional abstraction layer. We conclude from this thesis that it is important to abstract the interaction layer from the other layers of a Virtual Reality toolkit in order to provide a consistent interface to developers. We have shown that our framework is implementable and useful in the field, making it easier for developers to include interaction in their Virtual Reality applications. Our framework is able to handle all the current aspects of interaction in Virtual Reality, as well as being general enough to implement future interaction techniques. The framework is also applicable to different Virtual Reality toolkits and development platforms, making it ideal for developing general, cross-platform interactive Virtual Reality applications.
- 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
Determining the essential traits for successful retail pharmacists in the Port Elizabeth-Uitenhage metropole
- Authors: Melamed, Graham Morrison
- Date: 2000
- Subjects: Retail trade -- Port Elizabeth -- South Africa , Pharmacists -- South Africa , Pharmacy management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10831 , http://hdl.handle.net/10948/22 , Retail trade -- Port Elizabeth -- South Africa , Pharmacists -- South Africa , Pharmacy management
- Description: The research problem addressed in this study was to determine whether successful retail pharmacists exhibited specific traits. To achieve this objective a theoretical schedule of traits was developed, using relevant literature in which traits of entrepreneurs are described. The theoretical list consisted of the possession of the following traits: The need to achieve; Confidence in their abilities; The successful management of risk; Creativity and the possession of vision; The tendency/ability to view changes as opportunities; Internal locus of control; Leadership; High level of motivation; Tenacity; Communication skills. Each trait of the schedule was analysed using the literature identified during the literature study. The theoretical list was then used to develop a questionnaire to test the degree to which retail pharmacists in the Greater Port Elizabeth/Uitenhage Metropole concur. The empirical results obtained indicate a strong concurrence with the theoretical list of traits of successful retail pharmacists that was developed in the study. This resulted in the theoretical schedule being confirmed and accepted as a list of traits possessed by successful retail pharmacists.
- Full Text:
- Date Issued: 2000
- Authors: Melamed, Graham Morrison
- Date: 2000
- Subjects: Retail trade -- Port Elizabeth -- South Africa , Pharmacists -- South Africa , Pharmacy management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10831 , http://hdl.handle.net/10948/22 , Retail trade -- Port Elizabeth -- South Africa , Pharmacists -- South Africa , Pharmacy management
- Description: The research problem addressed in this study was to determine whether successful retail pharmacists exhibited specific traits. To achieve this objective a theoretical schedule of traits was developed, using relevant literature in which traits of entrepreneurs are described. The theoretical list consisted of the possession of the following traits: The need to achieve; Confidence in their abilities; The successful management of risk; Creativity and the possession of vision; The tendency/ability to view changes as opportunities; Internal locus of control; Leadership; High level of motivation; Tenacity; Communication skills. Each trait of the schedule was analysed using the literature identified during the literature study. The theoretical list was then used to develop a questionnaire to test the degree to which retail pharmacists in the Greater Port Elizabeth/Uitenhage Metropole concur. The empirical results obtained indicate a strong concurrence with the theoretical list of traits of successful retail pharmacists that was developed in the study. This resulted in the theoretical schedule being confirmed and accepted as a list of traits possessed by successful retail pharmacists.
- Full Text:
- Date Issued: 2000
Development of a Human Resource development strategy for the Border-Kei motor industry cluster
- Authors: Maritz, Andre
- Date: 2000
- Subjects: Manpower policy , Automobile industry and trade -- South Africa , Automobile industry and trade -- Management , Personnel management -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10832 , http://hdl.handle.net/10948/23 , Manpower policy , Automobile industry and trade -- South Africa , Automobile industry and trade -- Management , Personnel management -- South Africa
- Description: DaimlerChrysler’s investment of R 1.4 billion in its East London Plant has resulted in the formation and development of an industry cluster, with DaimlerChrysler as the main industry driver. The rest of the cluster is made up of suppliers to the motor industry, as well as organisations involved in attracting and stimulating economic development in the region. The investment by DaimlerChrysler signalled the entry of DaimlerChrysler South Africa (DCSA) into global markets, supplying right-hand drive C-Class vehicles to the rest of the world. As a global player, world-class quality standards are expected of DCSA and, in turn, their suppliers. World-Class skills are therefore expected of the employees from all of the organisations within the cluster. This factor poses a challenge to South African organisations who are subjected to and challenged by the legislation that seeks to address and correct the societal imbalance of the past. The research problem addressed in this study was two-fold. The first objective was to determine whether or not there was a competitive advantage to be gained by being part of an industry cluster. The second objective was to determine how suppliers to DCSA from within the cluster developed world-class skills despite the constraints imposed upon them by South African legislation. To achieve these objectives, a theoretical study was conducted on existing conditions within clusters worldwide, as well as on methods being implemented by global organisations to develop world-class skills. An empirical study, covering the topics of competitive advantage and developing world-class skills, was developed and sent to suppliers of DCSA to test the degree of concurrence between methods implemented in the Border-Kei Motor Industry Cluster and global organisations elsewhere in the world. The results of the empirical study indicated a strong concurrence in many of the factors, and essentially only differed in instances where a cluster was more developed.
- Full Text:
- Date Issued: 2000
- Authors: Maritz, Andre
- Date: 2000
- Subjects: Manpower policy , Automobile industry and trade -- South Africa , Automobile industry and trade -- Management , Personnel management -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10832 , http://hdl.handle.net/10948/23 , Manpower policy , Automobile industry and trade -- South Africa , Automobile industry and trade -- Management , Personnel management -- South Africa
- Description: DaimlerChrysler’s investment of R 1.4 billion in its East London Plant has resulted in the formation and development of an industry cluster, with DaimlerChrysler as the main industry driver. The rest of the cluster is made up of suppliers to the motor industry, as well as organisations involved in attracting and stimulating economic development in the region. The investment by DaimlerChrysler signalled the entry of DaimlerChrysler South Africa (DCSA) into global markets, supplying right-hand drive C-Class vehicles to the rest of the world. As a global player, world-class quality standards are expected of DCSA and, in turn, their suppliers. World-Class skills are therefore expected of the employees from all of the organisations within the cluster. This factor poses a challenge to South African organisations who are subjected to and challenged by the legislation that seeks to address and correct the societal imbalance of the past. The research problem addressed in this study was two-fold. The first objective was to determine whether or not there was a competitive advantage to be gained by being part of an industry cluster. The second objective was to determine how suppliers to DCSA from within the cluster developed world-class skills despite the constraints imposed upon them by South African legislation. To achieve these objectives, a theoretical study was conducted on existing conditions within clusters worldwide, as well as on methods being implemented by global organisations to develop world-class skills. An empirical study, covering the topics of competitive advantage and developing world-class skills, was developed and sent to suppliers of DCSA to test the degree of concurrence between methods implemented in the Border-Kei Motor Industry Cluster and global organisations elsewhere in the world. The results of the empirical study indicated a strong concurrence in many of the factors, and essentially only differed in instances where a cluster was more developed.
- Full Text:
- Date Issued: 2000
Development of a model of factors promoting team effectiveness in the automotive component industry
- Authors: Hutton, Timothy Strathearn
- Date: 2000
- Subjects: Teams in the workplace , Automobile industry and trade -- Management , Automobile industry and trade -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10833 , http://hdl.handle.net/10948/24 , Teams in the workplace , Automobile industry and trade -- Management , Automobile industry and trade -- South Africa
- Description: The research problem addressed in this study was to determine what makes a work team successful. To achieve this objective a theoretical model of factors promoting team effectiveness was developed, using relevant literature in which models for team effectiveness are described. The theoretical model consisted of the following factors: Individual background factors; Facilitation; Team Factors; Synergy; Team effectiveness; Organisational factors. Each factor of the model was broken down into dimensions that were then analysed using literature identified during the literature study. The theoretical model was then used to develop a questionnaire to test the degree to which managers working for automotive component manufacturers in the Port Elizabeth /Uitenhage magisterial district and falling under Chapter III of the Bargaining Council for the Motor Industry concur. The empirical results obtained indicate a strong concurrence with the theoretical model of factors promoting team effectiveness that was developed in the study. This resulted in the theoretical model being confirmed and being accepted as a model of factors promoting team effectiveness.
- Full Text:
- Date Issued: 2000
- Authors: Hutton, Timothy Strathearn
- Date: 2000
- Subjects: Teams in the workplace , Automobile industry and trade -- Management , Automobile industry and trade -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10833 , http://hdl.handle.net/10948/24 , Teams in the workplace , Automobile industry and trade -- Management , Automobile industry and trade -- South Africa
- Description: The research problem addressed in this study was to determine what makes a work team successful. To achieve this objective a theoretical model of factors promoting team effectiveness was developed, using relevant literature in which models for team effectiveness are described. The theoretical model consisted of the following factors: Individual background factors; Facilitation; Team Factors; Synergy; Team effectiveness; Organisational factors. Each factor of the model was broken down into dimensions that were then analysed using literature identified during the literature study. The theoretical model was then used to develop a questionnaire to test the degree to which managers working for automotive component manufacturers in the Port Elizabeth /Uitenhage magisterial district and falling under Chapter III of the Bargaining Council for the Motor Industry concur. The empirical results obtained indicate a strong concurrence with the theoretical model of factors promoting team effectiveness that was developed in the study. This resulted in the theoretical model being confirmed and being accepted as a model of factors promoting team effectiveness.
- Full Text:
- Date Issued: 2000