The alluvial diamond deposits of the lower Vaal river between Barkly West and the Vaal-Harts confluence in the Northern Cape province, South Africa
- Authors: Matheys, Fabrice Gilbert
- Date: 1991
- Subjects: Diamond deposits -- South Africa , Geology, Economic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4933 , http://hdl.handle.net/10962/d1005545 , Diamond deposits -- South Africa , Geology, Economic
- Description: The alluvial diamond deposits along the Vaal River, between Barkly West and the Vaal-Harts confluence, have been worked for more than one century by thousands of private diggers. The diamonds are recovered from two sedimentary units of Cenozoic age, the Older Gravels and the Younger Gravels. These rest on a basement of Ventersdorp Supergroup andesites and Karoo Sequence sediments, which have been intruded by Cretaceous kimberlites. The gravels are, in turn, overlain by the Riverton Formation and the Hutton Sand. On a large scale, tectonic setting, geomorphology and palaeoclimate have played a major role in the formation of diamondiferous placers in the area under investigation. A study of the sedimentology of the Younger Gravels was carried out with the aim of acquiring an understanding of the processes responsible for the economic concentration of high quality diamonds. An investigation of facies assemblages, clast composition, clast size, palaeocurrent directions external geometry, particle morphology and led to the conclusion that the Younger Gravels were deposited in a proximal braided stream environment during high discharge. A small-scale experiment was carried out to test the efficiency of different sedimentological trap sites in concentrating kimberlite indicator minerals. The results show that the concentration of indicator minerals is dependent on the size fraction chosen, bed roughness and gravel calibre. The examination of surface features on pyrope, picroilmenite and chrome diopside from kimberlite led to the conclusion that most of these minerals are locally derived. Diamond grade variations within the Younger Gravels are influenced by a combination of factors, including bed roughness, channel width and sorting process from the source. Alluvial diamond exploration programmes must take into account the tectonic setting, the palaeoclimate, the level of erosion, the stability of the drainage system in the area as well as the presence of local trap sites in the river profile. It is concluded that the diamonds are the product of a long and complex process of erosion, reworking and concentration and are derived from Cretaceous kimberlites in the area.
- Full Text:
- Date Issued: 1991
- Authors: Matheys, Fabrice Gilbert
- Date: 1991
- Subjects: Diamond deposits -- South Africa , Geology, Economic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4933 , http://hdl.handle.net/10962/d1005545 , Diamond deposits -- South Africa , Geology, Economic
- Description: The alluvial diamond deposits along the Vaal River, between Barkly West and the Vaal-Harts confluence, have been worked for more than one century by thousands of private diggers. The diamonds are recovered from two sedimentary units of Cenozoic age, the Older Gravels and the Younger Gravels. These rest on a basement of Ventersdorp Supergroup andesites and Karoo Sequence sediments, which have been intruded by Cretaceous kimberlites. The gravels are, in turn, overlain by the Riverton Formation and the Hutton Sand. On a large scale, tectonic setting, geomorphology and palaeoclimate have played a major role in the formation of diamondiferous placers in the area under investigation. A study of the sedimentology of the Younger Gravels was carried out with the aim of acquiring an understanding of the processes responsible for the economic concentration of high quality diamonds. An investigation of facies assemblages, clast composition, clast size, palaeocurrent directions external geometry, particle morphology and led to the conclusion that the Younger Gravels were deposited in a proximal braided stream environment during high discharge. A small-scale experiment was carried out to test the efficiency of different sedimentological trap sites in concentrating kimberlite indicator minerals. The results show that the concentration of indicator minerals is dependent on the size fraction chosen, bed roughness and gravel calibre. The examination of surface features on pyrope, picroilmenite and chrome diopside from kimberlite led to the conclusion that most of these minerals are locally derived. Diamond grade variations within the Younger Gravels are influenced by a combination of factors, including bed roughness, channel width and sorting process from the source. Alluvial diamond exploration programmes must take into account the tectonic setting, the palaeoclimate, the level of erosion, the stability of the drainage system in the area as well as the presence of local trap sites in the river profile. It is concluded that the diamonds are the product of a long and complex process of erosion, reworking and concentration and are derived from Cretaceous kimberlites in the area.
- Full Text:
- Date Issued: 1991
The contribution of meditative experiences to personal growth : a case study
- Authors: Knight, Zelda Gillian
- Date: 1991
- Subjects: Meditation Self-actualization (Psychology)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1466 , http://hdl.handle.net/10962/d1003347
- Description: A three month meditation programme based on Joseph Goldstein's (1976) instructions and discourses given at a Vipassana meditation retreat was implemented among four 17 year old white English-speaking school girls at a private non-racial co-educational high school in South Africa. The meditation experiences of all four subjects were noted, hut only one subject's meditative experiences were documented and used as a case study to explore their use as a tool for personal growth within the framework of ego-psychology and transpersonal psychology. It is concluded that the subject, who meditated on a daily basis, experienced personal growth primarily from the ego-psychology perspective and, it is interesting to note, less so from the transpersonal perspective. Three bypotheses have been put forward for this. Firstly, the actual length of the meditation programme may have been too short, and secondly, the daily meditation sessions too brief to facilitate a process of personal growth and development from within the trans personal psychology framework. Thirdly, the subject was an adolescent school girl and thus may not have been developmentally ready in terms of reaching a level of cognitive, emotional, social and spiritual maturity necessary to experience identification to the transpersonal self.
- Full Text:
- Date Issued: 1991
- Authors: Knight, Zelda Gillian
- Date: 1991
- Subjects: Meditation Self-actualization (Psychology)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1466 , http://hdl.handle.net/10962/d1003347
- Description: A three month meditation programme based on Joseph Goldstein's (1976) instructions and discourses given at a Vipassana meditation retreat was implemented among four 17 year old white English-speaking school girls at a private non-racial co-educational high school in South Africa. The meditation experiences of all four subjects were noted, hut only one subject's meditative experiences were documented and used as a case study to explore their use as a tool for personal growth within the framework of ego-psychology and transpersonal psychology. It is concluded that the subject, who meditated on a daily basis, experienced personal growth primarily from the ego-psychology perspective and, it is interesting to note, less so from the transpersonal perspective. Three bypotheses have been put forward for this. Firstly, the actual length of the meditation programme may have been too short, and secondly, the daily meditation sessions too brief to facilitate a process of personal growth and development from within the trans personal psychology framework. Thirdly, the subject was an adolescent school girl and thus may not have been developmentally ready in terms of reaching a level of cognitive, emotional, social and spiritual maturity necessary to experience identification to the transpersonal self.
- Full Text:
- Date Issued: 1991
The development, pursuit and maintenance of a South African Antarctic policy : 1926-1988
- Authors: Laverde, René
- Date: 1991
- Subjects: Antarctic Treaty -- (1959) , Antarctica -- History , South Africa -- Foreign relations -- Antarctica
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2523 , http://hdl.handle.net/10962/d1001852
- Description: Connections between South Africa and Antarctica can be traced as far back as the 1700s when European expeditions in search of the southern continent used Cape Town (and later Simonstown) as a base of operation. This link expanded considerably after formal British acquisition of the Cape of Good Hope in 1815, yet it was not until 1926 that an actual South African policy towards the Antarctic began to materialize. Once this policy was established it continued to be characterized by procrastination as well as resistance both from within and without South Africa. The history of South Africa's Antarctic policy can be divided into five periods: first, the commencement of the policy (focusing primarily on economic interests), 1926-1939; second, the pursuit of interests through the policy (focusing on political interests), 1944- 1958; third, the entrenchment of South Africa's interests in the Antarctic (by securing South Africa's position within the Antarctic Treaty System), 1958-1960; fourth, the expansion of and foreign assault on the policy (under the auspices of the Antarctic Treaty System), 1960-1988; and fifth, the defence of and future prospects for the policy (from United Nation's calls for South Africa's exclusion from the Antarctic Treaty System), since 1982. While resistance from inside and outside the government during the first two periods resulted from inadequacies in the South African Antarctic policy itself, resistance in the final two periods has centred upon non-Antarctic issues. As South Africa has faced ever-increasing exclusion from international governmental organizations over opposition to Its apartheid policies, organizations such as the Antarctic Treaty Organization have inevitably been drawn into the debate. As a result, the Consultative Parties of the Antarctic Treaty (of which South Africa is one of the original twelve) have been forced to deal with the following question: to what extent will political issues outside the scope of the management policies of the Antarctic Treaty Organization be allowed to affect the functioning of the Antarctic Treaty System? While the Consultative Parties continue to ponder this and the fact that South Africa's Consultative Status has become the most divisive factor within the Antarctic Treaty System, no final solutions to these issues appear likely before 1991.
- Full Text:
- Date Issued: 1991
- Authors: Laverde, René
- Date: 1991
- Subjects: Antarctic Treaty -- (1959) , Antarctica -- History , South Africa -- Foreign relations -- Antarctica
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2523 , http://hdl.handle.net/10962/d1001852
- Description: Connections between South Africa and Antarctica can be traced as far back as the 1700s when European expeditions in search of the southern continent used Cape Town (and later Simonstown) as a base of operation. This link expanded considerably after formal British acquisition of the Cape of Good Hope in 1815, yet it was not until 1926 that an actual South African policy towards the Antarctic began to materialize. Once this policy was established it continued to be characterized by procrastination as well as resistance both from within and without South Africa. The history of South Africa's Antarctic policy can be divided into five periods: first, the commencement of the policy (focusing primarily on economic interests), 1926-1939; second, the pursuit of interests through the policy (focusing on political interests), 1944- 1958; third, the entrenchment of South Africa's interests in the Antarctic (by securing South Africa's position within the Antarctic Treaty System), 1958-1960; fourth, the expansion of and foreign assault on the policy (under the auspices of the Antarctic Treaty System), 1960-1988; and fifth, the defence of and future prospects for the policy (from United Nation's calls for South Africa's exclusion from the Antarctic Treaty System), since 1982. While resistance from inside and outside the government during the first two periods resulted from inadequacies in the South African Antarctic policy itself, resistance in the final two periods has centred upon non-Antarctic issues. As South Africa has faced ever-increasing exclusion from international governmental organizations over opposition to Its apartheid policies, organizations such as the Antarctic Treaty Organization have inevitably been drawn into the debate. As a result, the Consultative Parties of the Antarctic Treaty (of which South Africa is one of the original twelve) have been forced to deal with the following question: to what extent will political issues outside the scope of the management policies of the Antarctic Treaty Organization be allowed to affect the functioning of the Antarctic Treaty System? While the Consultative Parties continue to ponder this and the fact that South Africa's Consultative Status has become the most divisive factor within the Antarctic Treaty System, no final solutions to these issues appear likely before 1991.
- Full Text:
- Date Issued: 1991
The digestive mechanisms of an intertidal grazer, the sea urchin Parechinus angulosus
- Authors: Sweijd, Neville Anthony
- Date: 1991
- Subjects: Sea urchins -- Nutrition , Sea urchins , Echinoida
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5662 , http://hdl.handle.net/10962/d1005346 , Sea urchins -- Nutrition , Sea urchins , Echinoida
- Description: Echinoids are important grazers in the near-shore ecosystem and can significantly effect their ecology. The sea urchin Parechinus angulosus occurs inter- and subtidally along the southern African coast. Within this range it consumes an extremely wide variety of algae. Since algal cell walls have an almost species specific chemical composition, the question arises as to how it can digest the algae that it consumes. In order to investigate the digestive mechanisms employed by P. angulosus, an ultrastructural study of the gut was undertaken to characterize the tissue and identify functional regions in the gut. Ten structural and storage polysaccharides commonly found in macroalgae were used as substrates to assay the digestive polysaccharidases of the sea urchin. The enteric bacteria of the sea urchin were isolated and tested separately for polysaccharidase activity using the same substrates. The results shown that the gut of Parechinus angulosus is regionally specialized, with the foregut primarily responsible for the production of hydrolytic enzymes, while the hindgut is primarily absorptive. The occurrence of lamellar bodies, heterolysosomes, cytoplasmic blebs and paddle cilia among other characteristic features of the digestive epithelium are described and discussed. Two levels of enzyme activity are apparent. Generally the urchin could hydrolyze the reserve polysaccharides, but only partially hydrolyze the structural polysaccharides, of red and green algae. P.angulosus was unable to digest alginic acid, the main structural polysaccharide of brown algae. Mixed cultures of bacteria utilized only the reserve polysaccharides of red and green algae. Significantly, the bacteria were able to hydrolyze alginic acid. Enteric bacteria also showed agarolytic activity. Parechinus angulosus has the ability to digest red and green algae. No lysozyme activity was detected. The enteric bacteria can digest the same algal reserve polysaccharides and so may compete for carbon in the gut. However, in the case of brown algae, bacteria have a potentially important endosymbiotic role as agents of digestion. These results correspond with food preference studies which have shown that, although P.angulosus consumes the kelp Ecklonia maxima, in the western Cape, it is amongst its least preferred food species. The reasons for this are its unpalatability and the urchin's inability to digest brown algae. The digestibility of algal material can be an important factor in determining algal-herbivore interactions.
- Full Text:
- Date Issued: 1991
- Authors: Sweijd, Neville Anthony
- Date: 1991
- Subjects: Sea urchins -- Nutrition , Sea urchins , Echinoida
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5662 , http://hdl.handle.net/10962/d1005346 , Sea urchins -- Nutrition , Sea urchins , Echinoida
- Description: Echinoids are important grazers in the near-shore ecosystem and can significantly effect their ecology. The sea urchin Parechinus angulosus occurs inter- and subtidally along the southern African coast. Within this range it consumes an extremely wide variety of algae. Since algal cell walls have an almost species specific chemical composition, the question arises as to how it can digest the algae that it consumes. In order to investigate the digestive mechanisms employed by P. angulosus, an ultrastructural study of the gut was undertaken to characterize the tissue and identify functional regions in the gut. Ten structural and storage polysaccharides commonly found in macroalgae were used as substrates to assay the digestive polysaccharidases of the sea urchin. The enteric bacteria of the sea urchin were isolated and tested separately for polysaccharidase activity using the same substrates. The results shown that the gut of Parechinus angulosus is regionally specialized, with the foregut primarily responsible for the production of hydrolytic enzymes, while the hindgut is primarily absorptive. The occurrence of lamellar bodies, heterolysosomes, cytoplasmic blebs and paddle cilia among other characteristic features of the digestive epithelium are described and discussed. Two levels of enzyme activity are apparent. Generally the urchin could hydrolyze the reserve polysaccharides, but only partially hydrolyze the structural polysaccharides, of red and green algae. P.angulosus was unable to digest alginic acid, the main structural polysaccharide of brown algae. Mixed cultures of bacteria utilized only the reserve polysaccharides of red and green algae. Significantly, the bacteria were able to hydrolyze alginic acid. Enteric bacteria also showed agarolytic activity. Parechinus angulosus has the ability to digest red and green algae. No lysozyme activity was detected. The enteric bacteria can digest the same algal reserve polysaccharides and so may compete for carbon in the gut. However, in the case of brown algae, bacteria have a potentially important endosymbiotic role as agents of digestion. These results correspond with food preference studies which have shown that, although P.angulosus consumes the kelp Ecklonia maxima, in the western Cape, it is amongst its least preferred food species. The reasons for this are its unpalatability and the urchin's inability to digest brown algae. The digestibility of algal material can be an important factor in determining algal-herbivore interactions.
- Full Text:
- Date Issued: 1991
The distribution patterns and community structure of the Tsitsikamma rocky littoral ichthyofauna
- Authors: Burger, Lynton Francois
- Date: 1991
- Subjects: Fishes -- South Africa -- Geographical distribution , Tripterygiidae -- South Africa -- Geographical distribution , Littoral plants -- South Africa -- Tsitsikamma , Littoral plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5260 , http://hdl.handle.net/10962/d1005104 , Fishes -- South Africa -- Geographical distribution , Tripterygiidae -- South Africa -- Geographical distribution , Littoral plants -- South Africa -- Tsitsikamma , Littoral plants
- Description: The results of a community survey of the rocky intertidal and subtidal reef ichthyofauna of the Tsitsikamma National Park and adjacent areas are presented. An updated species checklist is given, comprising 116 species of 46 families, including a new genus and species of Tripterygiid. Single species are shown to dominate, in terms of numbers, both the cryptic and subtidal components for all the areas sampled down the vertical profile. Species richness, evenness and diversity are found to increase with depth for both the cryptic and suprabenthic components. A community level feeding study shows an increase in trophic specialisation with depth and food availability is found to be an important factor delimiting littoral fish vertical distribution. The nursery function of the Tsitsikamma rocky littoral area is assessed and it is shown that shallow littoral areas as a whole are more important than intertidal pools alone in functioning as nurseries. The results of the study are found to fit into the existing trend of an increase in species richness and diversity, from west to east, along the South African coast. A significant difference is shown between the observed frequencies of species on exploited reefs outside the Park and unexploited reefs inside the Park. The density of the key reef predator Petrus rupestris is shown to be nine times more abundant on deep reef inside the park compared to deep reef outside the park (0.0045 fish/m² and 0.0005 fish/m² respectively) and a paucity of larger individuals of this species on exploited reefs is noted. Marked differences in the relative abundance of other species between exploited and unexploited reefs are evident and it is hypothesised that community disruption has occurred on exploited reefs, either directly or indirectly because of the removal of P. rupestris. These results are discussed in the context of marine reserves as a conservation strategy and a recommendation is made to extend the 5.6km seaward boundary of the Tsitsikamma National Park westwards to include the large concentration of presently exploited rocky reefs between the Blaaukrans river mouth and Natures Valley.
- Full Text:
- Date Issued: 1991
- Authors: Burger, Lynton Francois
- Date: 1991
- Subjects: Fishes -- South Africa -- Geographical distribution , Tripterygiidae -- South Africa -- Geographical distribution , Littoral plants -- South Africa -- Tsitsikamma , Littoral plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5260 , http://hdl.handle.net/10962/d1005104 , Fishes -- South Africa -- Geographical distribution , Tripterygiidae -- South Africa -- Geographical distribution , Littoral plants -- South Africa -- Tsitsikamma , Littoral plants
- Description: The results of a community survey of the rocky intertidal and subtidal reef ichthyofauna of the Tsitsikamma National Park and adjacent areas are presented. An updated species checklist is given, comprising 116 species of 46 families, including a new genus and species of Tripterygiid. Single species are shown to dominate, in terms of numbers, both the cryptic and subtidal components for all the areas sampled down the vertical profile. Species richness, evenness and diversity are found to increase with depth for both the cryptic and suprabenthic components. A community level feeding study shows an increase in trophic specialisation with depth and food availability is found to be an important factor delimiting littoral fish vertical distribution. The nursery function of the Tsitsikamma rocky littoral area is assessed and it is shown that shallow littoral areas as a whole are more important than intertidal pools alone in functioning as nurseries. The results of the study are found to fit into the existing trend of an increase in species richness and diversity, from west to east, along the South African coast. A significant difference is shown between the observed frequencies of species on exploited reefs outside the Park and unexploited reefs inside the Park. The density of the key reef predator Petrus rupestris is shown to be nine times more abundant on deep reef inside the park compared to deep reef outside the park (0.0045 fish/m² and 0.0005 fish/m² respectively) and a paucity of larger individuals of this species on exploited reefs is noted. Marked differences in the relative abundance of other species between exploited and unexploited reefs are evident and it is hypothesised that community disruption has occurred on exploited reefs, either directly or indirectly because of the removal of P. rupestris. These results are discussed in the context of marine reserves as a conservation strategy and a recommendation is made to extend the 5.6km seaward boundary of the Tsitsikamma National Park westwards to include the large concentration of presently exploited rocky reefs between the Blaaukrans river mouth and Natures Valley.
- Full Text:
- Date Issued: 1991
The ecology and culture of the rock catlet Chiloglanis pretoriae (Pisces : mochokidae)
- Authors: De Villiers, Pierre
- Date: 1991
- Subjects: Catfishes -- Africa , Catfishes -- Breeding -- Africa , Catfishes -- Ecology -- Africa , Fishes -- Cultural control -- Africa , Fishes -- Cultural control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5267 , http://hdl.handle.net/10962/d1005111 , Catfishes -- Africa , Catfishes -- Breeding -- Africa , Catfishes -- Ecology -- Africa , Fishes -- Cultural control -- Africa , Fishes -- Cultural control
- Description: Chiloglanis pretoriae is a rock catlet, indigenous to southern Africa. The aim of the study was to develop a technique to culture C. pretoriae as an alternative to harvesting and selling wild caught fish on the international aquarium trade. As nothing was known about the culture of African rock catlets an investigation into the biology and ecology of the species was necessary to develop the culture protocol. Chiloglanis pretoriae inhabits fast flowing rapids (current speeds over 0.6 metres per second). It is a serial interstitial gravel spawner, that spawns during the summer months. Chiloglanis pretoriae is a carnivorous fish species, feeding on aquatic insects. The natural growth rate is relatively fast in the first two years where after it levels off. Sexual maturity (50%) is attained within the first year (44mm total length). From the four cell stage, embryos took seven days to hatch, 16 days to first feeding and 75 days to reach the juvenile phase. The free embryos were well developed and readily accepted artificial feed at first feeding. The fish spawned readily, without hormone induction, in a continuous raceway. Spawning in the 801 retangular glass aquaria was irregular. The substrate within the raceway consisted of gravel and large rocks. The current was maintained at 0.6m/sec, temperature at 26± 0.6⁰C, dissolved oxygen concentrations at 7.1± 0.3mg/l, pH at 6.9± 0.2 and photoperiod at 16L:8D. Conductivity was monitored and remained within the acceptable range of C. pretoriae (84± 10uS/m).
- Full Text:
- Date Issued: 1991
- Authors: De Villiers, Pierre
- Date: 1991
- Subjects: Catfishes -- Africa , Catfishes -- Breeding -- Africa , Catfishes -- Ecology -- Africa , Fishes -- Cultural control -- Africa , Fishes -- Cultural control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5267 , http://hdl.handle.net/10962/d1005111 , Catfishes -- Africa , Catfishes -- Breeding -- Africa , Catfishes -- Ecology -- Africa , Fishes -- Cultural control -- Africa , Fishes -- Cultural control
- Description: Chiloglanis pretoriae is a rock catlet, indigenous to southern Africa. The aim of the study was to develop a technique to culture C. pretoriae as an alternative to harvesting and selling wild caught fish on the international aquarium trade. As nothing was known about the culture of African rock catlets an investigation into the biology and ecology of the species was necessary to develop the culture protocol. Chiloglanis pretoriae inhabits fast flowing rapids (current speeds over 0.6 metres per second). It is a serial interstitial gravel spawner, that spawns during the summer months. Chiloglanis pretoriae is a carnivorous fish species, feeding on aquatic insects. The natural growth rate is relatively fast in the first two years where after it levels off. Sexual maturity (50%) is attained within the first year (44mm total length). From the four cell stage, embryos took seven days to hatch, 16 days to first feeding and 75 days to reach the juvenile phase. The free embryos were well developed and readily accepted artificial feed at first feeding. The fish spawned readily, without hormone induction, in a continuous raceway. Spawning in the 801 retangular glass aquaria was irregular. The substrate within the raceway consisted of gravel and large rocks. The current was maintained at 0.6m/sec, temperature at 26± 0.6⁰C, dissolved oxygen concentrations at 7.1± 0.3mg/l, pH at 6.9± 0.2 and photoperiod at 16L:8D. Conductivity was monitored and remained within the acceptable range of C. pretoriae (84± 10uS/m).
- Full Text:
- Date Issued: 1991
The effect of teaching text organisation on reading in English as a second language
- Authors: Silburn, Gail Deirdre
- Date: 1991
- Subjects: English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1372 , http://hdl.handle.net/10962/d1001438
- Description: This research investigated the effect of teaching text organisation on reading in English second language to schoolgirls. All subjects underwent a training programme of five one-hour sessions on consecutive school days. The experimental group were trained in the use and recognition of top-level organisation as a reading strategy, based on work done by Bartlett (1978) and Carrell (1985). The control group were trained in unrelated grammar exercises. A pre-test was administered to each group before their programme began. Post-test 1 was administered immediately after the training was completed, and Post-test 2, three weeks later. These tests required a written recall of two passages once they had been read, and an answer to a question on their organisation. The null hypotheses stated that the experimental group's training in the use and recognition of top-level organisation as a reading strategy would make no difference in their ability to read and recall information or to recognise and use top-level organisation in their recalls. For the quantity of information recalled, no differences were found in the Pre-test and Post-test 1; a statistically significant difference was found in Post-test 2 in favour of the experimental group. For the quality of information recalled, the control group remembered more top-level idea units in the Pre-test; there was no difference in Post-test 1; the experimental group did better in three out of five levels in Post-test 2. There was no difference in the Pretest in either group's use of the passage's top-level organisation to structure recalls, but the experimental group did better in both post-tests. The control group did better in the Pre-test in recognising the passage's top-level organisation, but the experimental group did better in both post-tests. The null hypotheses were rejected as the experimental training made a difference, although this difference only became apparent three weeks later, and not immediately after the training. The experimental group's nullifying the control group's Pre-test advantage in Post-test 1 and surpassing it in Post-test 2, powerfully supports Bartlett's and Carrell's findings that teaching the strategy did make a difference and that this effect could be maintained over three weeks
- Full Text:
- Date Issued: 1991
- Authors: Silburn, Gail Deirdre
- Date: 1991
- Subjects: English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1372 , http://hdl.handle.net/10962/d1001438
- Description: This research investigated the effect of teaching text organisation on reading in English second language to schoolgirls. All subjects underwent a training programme of five one-hour sessions on consecutive school days. The experimental group were trained in the use and recognition of top-level organisation as a reading strategy, based on work done by Bartlett (1978) and Carrell (1985). The control group were trained in unrelated grammar exercises. A pre-test was administered to each group before their programme began. Post-test 1 was administered immediately after the training was completed, and Post-test 2, three weeks later. These tests required a written recall of two passages once they had been read, and an answer to a question on their organisation. The null hypotheses stated that the experimental group's training in the use and recognition of top-level organisation as a reading strategy would make no difference in their ability to read and recall information or to recognise and use top-level organisation in their recalls. For the quantity of information recalled, no differences were found in the Pre-test and Post-test 1; a statistically significant difference was found in Post-test 2 in favour of the experimental group. For the quality of information recalled, the control group remembered more top-level idea units in the Pre-test; there was no difference in Post-test 1; the experimental group did better in three out of five levels in Post-test 2. There was no difference in the Pretest in either group's use of the passage's top-level organisation to structure recalls, but the experimental group did better in both post-tests. The control group did better in the Pre-test in recognising the passage's top-level organisation, but the experimental group did better in both post-tests. The null hypotheses were rejected as the experimental training made a difference, although this difference only became apparent three weeks later, and not immediately after the training. The experimental group's nullifying the control group's Pre-test advantage in Post-test 1 and surpassing it in Post-test 2, powerfully supports Bartlett's and Carrell's findings that teaching the strategy did make a difference and that this effect could be maintained over three weeks
- Full Text:
- Date Issued: 1991
The genesis and controls of gold mineralization south of Rehoboth, Namibia
- Authors: Whitfield, Derek
- Date: 1991
- Subjects: Gold ores -- Geology -- Namibia , Gold ores -- Geology -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4948 , http://hdl.handle.net/10962/d1005560 , Gold ores -- Geology -- Namibia , Gold ores -- Geology -- Africa, Southern
- Description: Gold mineralization is hosted within gossanous quartz-haematite veins in volcano-sedimentary lithologies of the Klein Aub - Rehoboth basin of the Irumide Belt, Namibia. Mineralization and hydrothermal alteration are restricted to deformed lithologies particularly the metasediments. Lithological relationships, geochemistry and metallogenic characteristics of the Irumide Belt suggest an intra-continental rift setting. Copper mineralization is well known along the length of the belt, from Klein Aub in the southwest to Ghanzi in the northeast, whereas gold mineralization appears restricted to the Klein Aub Rehoboth basin. The gold is envisaged as having being leached initially from graben fill sequences during rift closure and basin dewatering. Location of the mineralization is strongly controlled by structure and lithological contact zones. Such zones are percieved as having acted as conduit zones for escaping mineralized fluids during basin closure and deformation. Apart from the lack of an effective mineralizing trap, all features consistent with the development of an ore deposit are present. The largest mineralization traps within the area studied are shear zones followed by lithological contact zones. The Mebi and Blanks gold mines are developed over large shear zones while the Swartmodder and Neuras gold mines are situated over mineralized lithological contacts. The Swartmodder copper mine yielded ore from a mineralized schist enclave within granite. Copper and gold occurrences are attributed to two contrasting styles of mineralization. Copper mineralization is suggested to have developed during initial rifting of the belt (ie. stratabound sedimentary exhalative type), while the gold and minor copper resulted from rift closure and basin dewatering. Although no economical orebody was realized during the course of this study a model is proposed for the development of mineralization within the Irumide basement lithologies as a working hypothesis for future exploration.
- Full Text:
- Date Issued: 1991
- Authors: Whitfield, Derek
- Date: 1991
- Subjects: Gold ores -- Geology -- Namibia , Gold ores -- Geology -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4948 , http://hdl.handle.net/10962/d1005560 , Gold ores -- Geology -- Namibia , Gold ores -- Geology -- Africa, Southern
- Description: Gold mineralization is hosted within gossanous quartz-haematite veins in volcano-sedimentary lithologies of the Klein Aub - Rehoboth basin of the Irumide Belt, Namibia. Mineralization and hydrothermal alteration are restricted to deformed lithologies particularly the metasediments. Lithological relationships, geochemistry and metallogenic characteristics of the Irumide Belt suggest an intra-continental rift setting. Copper mineralization is well known along the length of the belt, from Klein Aub in the southwest to Ghanzi in the northeast, whereas gold mineralization appears restricted to the Klein Aub Rehoboth basin. The gold is envisaged as having being leached initially from graben fill sequences during rift closure and basin dewatering. Location of the mineralization is strongly controlled by structure and lithological contact zones. Such zones are percieved as having acted as conduit zones for escaping mineralized fluids during basin closure and deformation. Apart from the lack of an effective mineralizing trap, all features consistent with the development of an ore deposit are present. The largest mineralization traps within the area studied are shear zones followed by lithological contact zones. The Mebi and Blanks gold mines are developed over large shear zones while the Swartmodder and Neuras gold mines are situated over mineralized lithological contacts. The Swartmodder copper mine yielded ore from a mineralized schist enclave within granite. Copper and gold occurrences are attributed to two contrasting styles of mineralization. Copper mineralization is suggested to have developed during initial rifting of the belt (ie. stratabound sedimentary exhalative type), while the gold and minor copper resulted from rift closure and basin dewatering. Although no economical orebody was realized during the course of this study a model is proposed for the development of mineralization within the Irumide basement lithologies as a working hypothesis for future exploration.
- Full Text:
- Date Issued: 1991
The genesis of ilmenite-rich heavy mineral deposits in the Bothaville/Delmas area, and an economic analysis of titanium, with particular reference to the Dwarsfontein deposit, Delmas district
- Authors: Brennan, Michael Brendan
- Date: 1991
- Subjects: Heavy minerals -- South Africa -- Transvaal , Titanium , Geology -- South Africa -- Transvaal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4949 , http://hdl.handle.net/10962/d1005561 , Heavy minerals -- South Africa -- Transvaal , Titanium , Geology -- South Africa -- Transvaal
- Description: A number of ilmenite-rich heavy mineral deposits occur along the northern margin of the intracratonic Karoo basin, and are hosted by the fluvio-deltaic Middle Ecca Group. Coastal reworking of delta front sands within a regressive, microtidal shoreline may be considered as a depositional model for the development of the heavy mineral deposits. An economic analysis of titanium suggests long term positive demand, and sustained high prices for this commodity. An evaluation of the Dwarsfontein ilmenite-rich heavy mineral deposit, using available data, indicates how important it is for deposits of this type to be situated close to an upgrading plant or export harbour.
- Full Text:
- Date Issued: 1991
- Authors: Brennan, Michael Brendan
- Date: 1991
- Subjects: Heavy minerals -- South Africa -- Transvaal , Titanium , Geology -- South Africa -- Transvaal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4949 , http://hdl.handle.net/10962/d1005561 , Heavy minerals -- South Africa -- Transvaal , Titanium , Geology -- South Africa -- Transvaal
- Description: A number of ilmenite-rich heavy mineral deposits occur along the northern margin of the intracratonic Karoo basin, and are hosted by the fluvio-deltaic Middle Ecca Group. Coastal reworking of delta front sands within a regressive, microtidal shoreline may be considered as a depositional model for the development of the heavy mineral deposits. An economic analysis of titanium suggests long term positive demand, and sustained high prices for this commodity. An evaluation of the Dwarsfontein ilmenite-rich heavy mineral deposit, using available data, indicates how important it is for deposits of this type to be situated close to an upgrading plant or export harbour.
- Full Text:
- Date Issued: 1991
The geology, petrology and geochemistry of the mineralization and hydrothermal alteration at Ongeama, Ongombo and Matchless West Extension, Namibia
- Authors: Moroni, Marilena
- Date: 1991
- Subjects: Geology -- Namibia , Petrology -- Namibia , Geochemistry -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5045 , http://hdl.handle.net/10962/d1007693 , Geology -- Namibia , Petrology -- Namibia , Geochemistry -- Namibia
- Description: The Matchless Amphibolite Belt (Damara Orogen, Namibia) hosts several volcanogenic-exhalative, sediment-hosted stratiform cupriferous pyrite deposits. These are thought to be related to submarine volcanism during the early evolutionary stages of a narrow Damaran ocean, the Matchless Trough. The mineralized bodies examined (Ongeama, Ongombo and Matchless West Extension) are deformed and metamorphosed to low-medium grade (greenschist-amphibolite facies). They are associated with metapelite and amphibolite country rocks, and crop out as prominent limonite-rich gossans. The elongated shape of the sulphide bodies suggests a structural control. The mineralization normally consists of a variably developed massive sulphide portion, either quartz-, talc- or amphibole-bearing, and a stratigraphically overlying, extensive horizon of sulphide- and baryte-bearing exhalite (magnetite quartzite and less common talc- and actinolite-bearing schists). Lateral and vertical mineralogical changes within the mineralization match with significant variations in the element distribution. A metamorphosed and deformed alteration pipe, indicating the position of the fluid conduit, can be recognized in association with some ore bodies. The formation of quartz-muscovite and chlorite alteration envelopes (Ongeama, Matchless West Extension) and the presence of subtle mineralogical changes (Ongombo) in the immediate wallrocks, accompanied by extensive redistribution, leaching and introduction of elements from outside, suggest the hydrothermal metasomatic origin of the alteration zones. Element zoning within the mineralized bodies can be related to the original position of the vent, possibly coinciding with the intersection of the axis of the alteration pipe with the sulphide body. Cu, Zn, Au (pro parte) and Mo are enriched proximal to the vent, whereas Pb, Ba, Mn, Ag, Au, Sn, Bi and W enrichment characterizes the distal facies of the mineralization. In spite of the obliterating and disrupting effects of the regional dynamo-metamorphism, the element distribution within the mineralization and alteration zones examined is comparable with the geochemical trends observed in present-day mineralizing systems in early- stage oceanic environments (e.g. Guaymas Basin). During exploration for blind volcanogenic mineralization, the detection of hydrothermally altered rocks is fundamental in indicating the proximity to the mineralization. The localization of the alteration zone is also important in the interpretation of the regional geology of the explored area: in deformed terrains the assessment of the stratigraphic position of the alteration zone, relative to the mineralization, helps in establishing the polarity of the sequence.
- Full Text:
- Date Issued: 1991
- Authors: Moroni, Marilena
- Date: 1991
- Subjects: Geology -- Namibia , Petrology -- Namibia , Geochemistry -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5045 , http://hdl.handle.net/10962/d1007693 , Geology -- Namibia , Petrology -- Namibia , Geochemistry -- Namibia
- Description: The Matchless Amphibolite Belt (Damara Orogen, Namibia) hosts several volcanogenic-exhalative, sediment-hosted stratiform cupriferous pyrite deposits. These are thought to be related to submarine volcanism during the early evolutionary stages of a narrow Damaran ocean, the Matchless Trough. The mineralized bodies examined (Ongeama, Ongombo and Matchless West Extension) are deformed and metamorphosed to low-medium grade (greenschist-amphibolite facies). They are associated with metapelite and amphibolite country rocks, and crop out as prominent limonite-rich gossans. The elongated shape of the sulphide bodies suggests a structural control. The mineralization normally consists of a variably developed massive sulphide portion, either quartz-, talc- or amphibole-bearing, and a stratigraphically overlying, extensive horizon of sulphide- and baryte-bearing exhalite (magnetite quartzite and less common talc- and actinolite-bearing schists). Lateral and vertical mineralogical changes within the mineralization match with significant variations in the element distribution. A metamorphosed and deformed alteration pipe, indicating the position of the fluid conduit, can be recognized in association with some ore bodies. The formation of quartz-muscovite and chlorite alteration envelopes (Ongeama, Matchless West Extension) and the presence of subtle mineralogical changes (Ongombo) in the immediate wallrocks, accompanied by extensive redistribution, leaching and introduction of elements from outside, suggest the hydrothermal metasomatic origin of the alteration zones. Element zoning within the mineralized bodies can be related to the original position of the vent, possibly coinciding with the intersection of the axis of the alteration pipe with the sulphide body. Cu, Zn, Au (pro parte) and Mo are enriched proximal to the vent, whereas Pb, Ba, Mn, Ag, Au, Sn, Bi and W enrichment characterizes the distal facies of the mineralization. In spite of the obliterating and disrupting effects of the regional dynamo-metamorphism, the element distribution within the mineralization and alteration zones examined is comparable with the geochemical trends observed in present-day mineralizing systems in early- stage oceanic environments (e.g. Guaymas Basin). During exploration for blind volcanogenic mineralization, the detection of hydrothermally altered rocks is fundamental in indicating the proximity to the mineralization. The localization of the alteration zone is also important in the interpretation of the regional geology of the explored area: in deformed terrains the assessment of the stratigraphic position of the alteration zone, relative to the mineralization, helps in establishing the polarity of the sequence.
- Full Text:
- Date Issued: 1991
The hermeneutic value of the Daseinsanalytic approach to dream interpretation in psychotherapy: a case study
- Authors: Oberholzer, Sofia Adriana
- Date: 1991
- Subjects: Boss, Medard, 1903-1990 , Dreams -- Psychological aspects -- Case studies , Dream interpretation -- Case studies , Psychotherapy -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3222 , http://hdl.handle.net/10962/d1012988
- Description: The purpose of this study was to investigate the hermeneutic value of the Daseinsanalytic approach to dream interpretation in the process of psychotherapy. After delineating the Daseinsanalytic view on dream interpretation, with emphasis on the conceptualization of Medard Boss, the study explores the usefulness and validity of the case study as a method of investigating the content and process of psychotherapy. A psychodynamic formulation of the presenting problem is based on the conceptualization of the nature and etiology of neurosis as delineated by Andras Angyal, with particular reference to the pattern of noncommitment. The dreams included in the case material are then examined to determine to what degree they facilitated insight into the subjective experience and phenomenological existence of the dreamer, and what effect the dream interpretation based on the Daseinsanalytic approach had on the process of therapy. It is established that a phenomenological understanding of the client's dreams corresponds with his subjective experience of his emotional and existential condition, and that positive changes in the content of the dreams during the course of therapy correspond with overt, observable changes in his behaviour, ideation and mood. Based on these findings, the case study leads to the conclusion that the Daseinsanalytic approach to dream interpretation has hermeneutic value in the process of psychotherapy.
- Full Text:
- Date Issued: 1991
- Authors: Oberholzer, Sofia Adriana
- Date: 1991
- Subjects: Boss, Medard, 1903-1990 , Dreams -- Psychological aspects -- Case studies , Dream interpretation -- Case studies , Psychotherapy -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3222 , http://hdl.handle.net/10962/d1012988
- Description: The purpose of this study was to investigate the hermeneutic value of the Daseinsanalytic approach to dream interpretation in the process of psychotherapy. After delineating the Daseinsanalytic view on dream interpretation, with emphasis on the conceptualization of Medard Boss, the study explores the usefulness and validity of the case study as a method of investigating the content and process of psychotherapy. A psychodynamic formulation of the presenting problem is based on the conceptualization of the nature and etiology of neurosis as delineated by Andras Angyal, with particular reference to the pattern of noncommitment. The dreams included in the case material are then examined to determine to what degree they facilitated insight into the subjective experience and phenomenological existence of the dreamer, and what effect the dream interpretation based on the Daseinsanalytic approach had on the process of therapy. It is established that a phenomenological understanding of the client's dreams corresponds with his subjective experience of his emotional and existential condition, and that positive changes in the content of the dreams during the course of therapy correspond with overt, observable changes in his behaviour, ideation and mood. Based on these findings, the case study leads to the conclusion that the Daseinsanalytic approach to dream interpretation has hermeneutic value in the process of psychotherapy.
- Full Text:
- Date Issued: 1991
The informal sector in the Eastern Cape: a case study of New Brighton and Kwamagxaki, Port Elizabeth
- Authors: Sofisa, Thembela Nicholas
- Date: 1991
- Subjects: Informal sector (Economics) -- South Africa -- Port Elizabeth , Self-employed -- South Africa , New Brighton (Port Elizabeth, South Africa) , Port Elizabeth (South Africa) -- Economic conditions , KwaMagxaki (Port Elizabeth, South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:934 , http://hdl.handle.net/10962/d1002667 , Informal sector (Economics) -- South Africa -- Port Elizabeth , Self-employed -- South Africa , New Brighton (Port Elizabeth, South Africa) , Port Elizabeth (South Africa) -- Economic conditions
- Description: Recently, researchers have shown enormous interest in the informal sector due to extensive poverty and rising unemployment trend in the South African economy. These problems have worsened in the Port Elizabeth economy, as most entrepreneurs have scaled down their operations or liquidated their businesses due to a structural decline in the manufacturing sector and periodic recessions in the national economy. Undoubtedly, the informal sector has become a reasonable economic alternative as far as income accumulation and employment generation. The present study shows that the informal sector is characterised mainly by self-employment and also the income from this sector has also improved the standard of living of most sampled households in New Brighton and KwaMagxaki. The aim of this thesis, then, is to evaluate the nature, extent, meaning and influence of the informal sector in the Port Elizabeth Black economy. However, this can only be achieved once the informal sector is placed within the appropriate theoretical framework. This is done by comparing and contrasting the different conceptualisations of the informal sector in the literature. In conclusion, the thesis combines the different conceptualisations of the informal sector in the literature with the empirical evidence from the Port Elizabeth townships' informal sector. The important findings of the study are: The informal sector is mainly characterised by distributive activities than productive activities. Women comprised 62% of the informal sector. Economically-active members of the economy are in the informal sector. Education levels in this sector are relatively low. The informal sector is characterised by one-man businesses with few employees who are also family members. There was no trace of migrants in the informal sector. The informal sector is characterised by linkages. Informal income alleviates conditions of poverty. Policies have to implemented for the development of the informal sector. Twenty-three percent of the households in New Brighton were in the informal sector and only 6% in KwaMagxaki. Although, this study focuses in Port Elizabeth, it is the intention that the results presented will provide a broad overview of what the informal sector is.
- Full Text:
- Date Issued: 1991
The informal sector in the Eastern Cape: a case study of New Brighton and Kwamagxaki, Port Elizabeth
- Authors: Sofisa, Thembela Nicholas
- Date: 1991
- Subjects: Informal sector (Economics) -- South Africa -- Port Elizabeth , Self-employed -- South Africa , New Brighton (Port Elizabeth, South Africa) , Port Elizabeth (South Africa) -- Economic conditions , KwaMagxaki (Port Elizabeth, South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:934 , http://hdl.handle.net/10962/d1002667 , Informal sector (Economics) -- South Africa -- Port Elizabeth , Self-employed -- South Africa , New Brighton (Port Elizabeth, South Africa) , Port Elizabeth (South Africa) -- Economic conditions
- Description: Recently, researchers have shown enormous interest in the informal sector due to extensive poverty and rising unemployment trend in the South African economy. These problems have worsened in the Port Elizabeth economy, as most entrepreneurs have scaled down their operations or liquidated their businesses due to a structural decline in the manufacturing sector and periodic recessions in the national economy. Undoubtedly, the informal sector has become a reasonable economic alternative as far as income accumulation and employment generation. The present study shows that the informal sector is characterised mainly by self-employment and also the income from this sector has also improved the standard of living of most sampled households in New Brighton and KwaMagxaki. The aim of this thesis, then, is to evaluate the nature, extent, meaning and influence of the informal sector in the Port Elizabeth Black economy. However, this can only be achieved once the informal sector is placed within the appropriate theoretical framework. This is done by comparing and contrasting the different conceptualisations of the informal sector in the literature. In conclusion, the thesis combines the different conceptualisations of the informal sector in the literature with the empirical evidence from the Port Elizabeth townships' informal sector. The important findings of the study are: The informal sector is mainly characterised by distributive activities than productive activities. Women comprised 62% of the informal sector. Economically-active members of the economy are in the informal sector. Education levels in this sector are relatively low. The informal sector is characterised by one-man businesses with few employees who are also family members. There was no trace of migrants in the informal sector. The informal sector is characterised by linkages. Informal income alleviates conditions of poverty. Policies have to implemented for the development of the informal sector. Twenty-three percent of the households in New Brighton were in the informal sector and only 6% in KwaMagxaki. Although, this study focuses in Port Elizabeth, it is the intention that the results presented will provide a broad overview of what the informal sector is.
- Full Text:
- Date Issued: 1991
The nature and origin of gold mineralization in the Tugela valley, Natal Structural and Metamorphic Province
- Authors: De Klerk, Ian Duncan
- Date: 1991
- Subjects: Gold ores -- Geology -- South Africa , Gold mines and mining -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4979 , http://hdl.handle.net/10962/d1005591 , Gold ores -- Geology -- South Africa , Gold mines and mining -- South Africa
- Description: The project area is situated within the Tugela Valley, located in the Northern Marginal Zone of the Natal Structural and Metamorphic Province, and this work outlines the different styles of gold mineralization found in the Tugela Valley. Two different styles have been recognized and both have economic significance:- 1) Epigenetic shear zone-hosted gold occurs in late-stage relatively undeformed thin quartz veins confined to shear zones, and is present in both the greenschist facies Natal Thrust Belt and the amphibolite facies Natal Nappe Complex. However the vast majority of these occurrences are concentrated within the thrust front (i.e. the Natal Thrust Belt). The gold grades (up to 7 g/t) and the hydrothermal alteration assemblages associated with the epigenetic deposits have been documented. 2) An as yet unrecognized occurrence of syngenetic gold mineralization is found associated with the sediment-hosted exhalative massive, to semi-massive, sulphides of the iThuma prospect, located within the amphibolite facies Natal Nappe Complex. Here gold (up to 3 g/t) is concentrated together with the main sulphide are, as well as some gold enrichment (230ppb) in the hydrothermally altered footwall feeder pipe. It is proposed that the epigenetic mineralization was formed as a consequence of the northward directed abduction of the major thrust slices of the Natal Nappe Complex. This increased the permeability of the rocks and provided channelways for the focussing of fluids. Deposition took place at the thrust front where metamorphic hydrothermal fluids interacted with meteoric water.
- Full Text:
- Date Issued: 1991
- Authors: De Klerk, Ian Duncan
- Date: 1991
- Subjects: Gold ores -- Geology -- South Africa , Gold mines and mining -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4979 , http://hdl.handle.net/10962/d1005591 , Gold ores -- Geology -- South Africa , Gold mines and mining -- South Africa
- Description: The project area is situated within the Tugela Valley, located in the Northern Marginal Zone of the Natal Structural and Metamorphic Province, and this work outlines the different styles of gold mineralization found in the Tugela Valley. Two different styles have been recognized and both have economic significance:- 1) Epigenetic shear zone-hosted gold occurs in late-stage relatively undeformed thin quartz veins confined to shear zones, and is present in both the greenschist facies Natal Thrust Belt and the amphibolite facies Natal Nappe Complex. However the vast majority of these occurrences are concentrated within the thrust front (i.e. the Natal Thrust Belt). The gold grades (up to 7 g/t) and the hydrothermal alteration assemblages associated with the epigenetic deposits have been documented. 2) An as yet unrecognized occurrence of syngenetic gold mineralization is found associated with the sediment-hosted exhalative massive, to semi-massive, sulphides of the iThuma prospect, located within the amphibolite facies Natal Nappe Complex. Here gold (up to 3 g/t) is concentrated together with the main sulphide are, as well as some gold enrichment (230ppb) in the hydrothermally altered footwall feeder pipe. It is proposed that the epigenetic mineralization was formed as a consequence of the northward directed abduction of the major thrust slices of the Natal Nappe Complex. This increased the permeability of the rocks and provided channelways for the focussing of fluids. Deposition took place at the thrust front where metamorphic hydrothermal fluids interacted with meteoric water.
- Full Text:
- Date Issued: 1991
The notion of physicality in vocal training for the performer in South African theatre, with particular reference to the Alexander technique
- Authors: Cox, Frances Jayne
- Date: 1991
- Subjects: Voice culture , Alexander technique , Drama -- Study and teaching
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2134 , http://hdl.handle.net/10962/d1002366 , Voice culture , Alexander technique , Drama -- Study and teaching
- Description: Voice training has been influenced by separatist attitudes which have allowed for classes which train the body to be separate from those which train the voice. This study acknowledges that to train an actor in separate compartments and then expect the completeness of human expression in performance, is to train under false pretences. There is a need to address the imbalance of separatism and this is examined within the context of voice training. An holistic approach to voice training forms the basis of the argument, which focuses on the need to re-educate the notion of physicality in voice training. Chapter one proposes an understanding of the notion of physicality by drawing on the attitudes of selected theatre practitioners towards the physical nature of the theatre encounter. The expressive energies of the actor's body are responsible for the physicalisation of a play; for this reason the movement of voice and speech is not only examined as source movement, but also as the movement of an actor's response and communication. Chapter two examines some practices which led to attitudes of separatism in voice training, and introduces prevalent practices which are attempting to involve the energy of the physical experience. Chapter three proposes that the Alexander technique be used as the foundation for an awareness of individual physicality. Where chapter one examines the theory of this notion, chapter three proposes an experiential understanding of the same. The Alexander technique is a training in effective body use and it's principles are fundamental to an awareness of body use and functioning. It is argued that these principles should underlie a re-education of physicality. The final chapter of the thesis argues for physicality in South African voice training programmes which would complement the physicality of contemporary theatre forms. It is hoped that this study will provide further incentive for the continued review and adjustment of drama training in South Africa.
- Full Text:
- Date Issued: 1991
- Authors: Cox, Frances Jayne
- Date: 1991
- Subjects: Voice culture , Alexander technique , Drama -- Study and teaching
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2134 , http://hdl.handle.net/10962/d1002366 , Voice culture , Alexander technique , Drama -- Study and teaching
- Description: Voice training has been influenced by separatist attitudes which have allowed for classes which train the body to be separate from those which train the voice. This study acknowledges that to train an actor in separate compartments and then expect the completeness of human expression in performance, is to train under false pretences. There is a need to address the imbalance of separatism and this is examined within the context of voice training. An holistic approach to voice training forms the basis of the argument, which focuses on the need to re-educate the notion of physicality in voice training. Chapter one proposes an understanding of the notion of physicality by drawing on the attitudes of selected theatre practitioners towards the physical nature of the theatre encounter. The expressive energies of the actor's body are responsible for the physicalisation of a play; for this reason the movement of voice and speech is not only examined as source movement, but also as the movement of an actor's response and communication. Chapter two examines some practices which led to attitudes of separatism in voice training, and introduces prevalent practices which are attempting to involve the energy of the physical experience. Chapter three proposes that the Alexander technique be used as the foundation for an awareness of individual physicality. Where chapter one examines the theory of this notion, chapter three proposes an experiential understanding of the same. The Alexander technique is a training in effective body use and it's principles are fundamental to an awareness of body use and functioning. It is argued that these principles should underlie a re-education of physicality. The final chapter of the thesis argues for physicality in South African voice training programmes which would complement the physicality of contemporary theatre forms. It is hoped that this study will provide further incentive for the continued review and adjustment of drama training in South Africa.
- Full Text:
- Date Issued: 1991
The pineal gland as a model to elucidate the primary mode of action of sympathoactive agents
- Authors: Welman, Alan David
- Date: 1991
- Subjects: Pineal gland , Cythochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3876 , http://hdl.handle.net/10962/d1001610
- Description: An attempt was made to use the pineal gland as a model for the study of the primary mode of action of sympathoactive agents. Two drugs were investigated, viz. alpha-methyldopa and ephedrine whose mode of action is not entirely clear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radioactive serotonin to melatonin (aMT) , as well as its precursor Nacetylserotonin (aHT). This treatment was also found to raise Nacetyltransferase (NAT) activity. These increases associated with alpha-methyldopa treatment were further enhanced by the beta-adrenergic agonist, isoproterenol, suggesting a supersensitivity-type effect occurring at the level of the beta-receptor. A subsequent binding study, however, showed a decrease in beta-receptor binding with exposure to alpha-methyldopa, providing mitigating evidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha-methyldopa acts as an alpha 1 and beta-adrenergic agonist, resulting in greater melatonin (aMT) and N-acetylserotonin (aHT) synthesis than by a beta-adrenergic agonist, isoproterenol. Combined treatment of pineals with alpha-methyldopa and an alphareceptor blocker, phentolamine, resulted in melatonin (aMT) , Nacetylserotonin (aHT) , and N-acetyltransferase (NAT) activity levels which were lower than those obtained with alpha-methyldopa treatment alone, thus confirming the alpha-adrenergic activity of the metabolite of alpha-methyldopa. Additional pineal metabolites were isolated and measured simultaneously in the organ culture experiments. Organ cultures of rat pineal glands treated with ephedrine showed raised levels of melatonin (aMT) and N-acetylserotonin (aHT). Treatment with ephedrine also produced raised N-acetyltransferase activity. A further enhancement of these parameters was induced by norepinephrine, suggesting a supersensitivity-type effect occurring at the level of the beta-adrenergic receptor. Rats were treated with reserpine (a norepinephrine depleter) and the pineals exposed to ephedrine. Endogenous norepinephrine normally released by the action of ephedrine was thus absent, and under these conditions, levels of melatonin (aMT) and N-acetylserotonin (aHT) were reduced. N-acetyltransferase (NAT) activity was also reduced, but maintained levels pointing to substantial adrenergic activity of ephedrine as well as norepinephrine released by virtue of the drug's action. A subsequent binding study showed a decrease in beta-adrenergic receptor binding with exposure to ephedrine and a further decrease in ephedrine treated pineals from reserpine treated rats, thus ruling out the occurrence of a supersensitivity phenomenon. It is possible that both ephedrine and released norepinephrine have alpha- and beta-receptor activity. Additional pineal metabolites were isolated and measured in the organ culture experiments. A 16-hour time profile of the production of melatonin (aMT) and N-acetylserotonin (aHT) with norepinephrine and ephedrine treatment provided useful information regarding the course of action of the two agents. A pineal cell-culture system was developed and exposed to ephedrine and norepinephrine. N-acetyltransferase (NAT) activity levels measured after exposure to these agents were raised, confirming the adrenergic activity of both in the model. Finally, an HPLC system coupled to a UV detector was used in an attempt to measure melatonin (aMT) extracted from pineal organ culture media. The results showed that melatonin could be measured by this method, however, a more sensitive detection system was recommended for future work.
- Full Text:
- Date Issued: 1991
- Authors: Welman, Alan David
- Date: 1991
- Subjects: Pineal gland , Cythochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3876 , http://hdl.handle.net/10962/d1001610
- Description: An attempt was made to use the pineal gland as a model for the study of the primary mode of action of sympathoactive agents. Two drugs were investigated, viz. alpha-methyldopa and ephedrine whose mode of action is not entirely clear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radioactive serotonin to melatonin (aMT) , as well as its precursor Nacetylserotonin (aHT). This treatment was also found to raise Nacetyltransferase (NAT) activity. These increases associated with alpha-methyldopa treatment were further enhanced by the beta-adrenergic agonist, isoproterenol, suggesting a supersensitivity-type effect occurring at the level of the beta-receptor. A subsequent binding study, however, showed a decrease in beta-receptor binding with exposure to alpha-methyldopa, providing mitigating evidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha-methyldopa acts as an alpha 1 and beta-adrenergic agonist, resulting in greater melatonin (aMT) and N-acetylserotonin (aHT) synthesis than by a beta-adrenergic agonist, isoproterenol. Combined treatment of pineals with alpha-methyldopa and an alphareceptor blocker, phentolamine, resulted in melatonin (aMT) , Nacetylserotonin (aHT) , and N-acetyltransferase (NAT) activity levels which were lower than those obtained with alpha-methyldopa treatment alone, thus confirming the alpha-adrenergic activity of the metabolite of alpha-methyldopa. Additional pineal metabolites were isolated and measured simultaneously in the organ culture experiments. Organ cultures of rat pineal glands treated with ephedrine showed raised levels of melatonin (aMT) and N-acetylserotonin (aHT). Treatment with ephedrine also produced raised N-acetyltransferase activity. A further enhancement of these parameters was induced by norepinephrine, suggesting a supersensitivity-type effect occurring at the level of the beta-adrenergic receptor. Rats were treated with reserpine (a norepinephrine depleter) and the pineals exposed to ephedrine. Endogenous norepinephrine normally released by the action of ephedrine was thus absent, and under these conditions, levels of melatonin (aMT) and N-acetylserotonin (aHT) were reduced. N-acetyltransferase (NAT) activity was also reduced, but maintained levels pointing to substantial adrenergic activity of ephedrine as well as norepinephrine released by virtue of the drug's action. A subsequent binding study showed a decrease in beta-adrenergic receptor binding with exposure to ephedrine and a further decrease in ephedrine treated pineals from reserpine treated rats, thus ruling out the occurrence of a supersensitivity phenomenon. It is possible that both ephedrine and released norepinephrine have alpha- and beta-receptor activity. Additional pineal metabolites were isolated and measured in the organ culture experiments. A 16-hour time profile of the production of melatonin (aMT) and N-acetylserotonin (aHT) with norepinephrine and ephedrine treatment provided useful information regarding the course of action of the two agents. A pineal cell-culture system was developed and exposed to ephedrine and norepinephrine. N-acetyltransferase (NAT) activity levels measured after exposure to these agents were raised, confirming the adrenergic activity of both in the model. Finally, an HPLC system coupled to a UV detector was used in an attempt to measure melatonin (aMT) extracted from pineal organ culture media. The results showed that melatonin could be measured by this method, however, a more sensitive detection system was recommended for future work.
- Full Text:
- Date Issued: 1991
The pineal gland as a model to elucidate the primary mode of action of sympathoactive agents
- Authors: Welman, Alan David
- Date: 1991
- Subjects: Pineal gland , Cythochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4279 , http://hdl.handle.net/10962/d1002005 , Pineal gland
- Description: An attempt was made to use the pineal gland as a model for the study of the primary mode of action of sympathoactive agents. Two drugs were investigated, viz. alpha-methyldopa and ephedrine whose mode of action is not entirely clear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radioactive serotonin to melatonin (aMT) , as well as its precursor Nacetylserotonin (aHT). This treatment was also found to raise Nacetyltransferase (NAT) activity. These increases associated with alpha-methyldopa treatment were further enhanced by the beta-adrenergic agonist, isoproterenol, suggesting a supersensitivity-type effect occurring at the level of the beta-receptor. A subsequent binding study, however, showed a decrease in beta-receptor binding with exposure to alpha-methyldopa, providing mitigating evidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha-methyldopa acts as an alpha 1 and beta-adrenergic agonist, resulting in greater melatonin (aMT) and N-acetylserotonin (aHT) synthesis than by a beta-adrenergic agonist, isoproterenol. Combined treatment of pineals with alpha-methyldopa and an alphareceptor blocker, phentolamine, resulted in melatonin (aMT) , Nacetylserotonin (aHT) , and N-acetyltransferase (NAT) activity levels which were lower than those obtained with alpha-methyldopa treatment alone, thus confirming the alpha-adrenergic activity of the metabolite of alpha-methyldopa. Additional pineal metabolites were isolated and measured simultaneously in the organ culture experiments. Organ cultures of rat pineal glands treated with ephedrine showed raised levels of melatonin (aMT) and N-acetylserotonin (aHT). Treatment with ephedrine also produced raised N-acetyltransferase activity. A further enhancement of these parameters was induced by norepinephrine, suggesting a supersensitivity-type effect occurring at the level of the beta-adrenergic receptor. Rats were treated with reserpine (a norepinephrine depleter) and the pineals exposed to ephedrine. Endogenous norepinephrine normally released by the action of ephedrine was thus absent, and under these conditions, levels of melatonin (aMT) and N-acetylserotonin (aHT) were reduced. N-acetyltransferase (NAT) activity was also reduced, but maintained levels pointing to substantial adrenergic activity of ephedrine as well as norepinephrine released by virtue of the drug's action. A subsequent binding study showed a decrease in beta-adrenergic receptor binding with exposure to ephedrine and a further decrease in ephedrine treated pineals from reserpine treated rats, thus ruling out the occurrence of a supersensitivity phenomenon. It is possible that both ephedrine and released norepinephrine have alpha- and beta-receptor activity. Additional pineal metabolites were isolated and measured in the organ culture experiments. A 16-hour time profile of the production of melatonin (aMT) and N-acetylserotonin (aHT) with norepinephrine and ephedrine treatment provided useful information regarding the course of action of the two agents. A pineal cell-culture system was developed and exposed to ephedrine and norepinephrine. N-acetyltransferase (NAT) activity levels measured after exposure to these agents were raised, confirming the adrenergic activity of both in the model. Finally, an HPLC system coupled to a UV detector was used in an attempt to measure melatonin (aMT) extracted from pineal organ culture media. The results showed that melatonin could be measured by this method, however, a more sensitive detection system was recommended for future work
- Full Text:
- Date Issued: 1991
- Authors: Welman, Alan David
- Date: 1991
- Subjects: Pineal gland , Cythochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4279 , http://hdl.handle.net/10962/d1002005 , Pineal gland
- Description: An attempt was made to use the pineal gland as a model for the study of the primary mode of action of sympathoactive agents. Two drugs were investigated, viz. alpha-methyldopa and ephedrine whose mode of action is not entirely clear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radioactive serotonin to melatonin (aMT) , as well as its precursor Nacetylserotonin (aHT). This treatment was also found to raise Nacetyltransferase (NAT) activity. These increases associated with alpha-methyldopa treatment were further enhanced by the beta-adrenergic agonist, isoproterenol, suggesting a supersensitivity-type effect occurring at the level of the beta-receptor. A subsequent binding study, however, showed a decrease in beta-receptor binding with exposure to alpha-methyldopa, providing mitigating evidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha-methyldopa acts as an alpha 1 and beta-adrenergic agonist, resulting in greater melatonin (aMT) and N-acetylserotonin (aHT) synthesis than by a beta-adrenergic agonist, isoproterenol. Combined treatment of pineals with alpha-methyldopa and an alphareceptor blocker, phentolamine, resulted in melatonin (aMT) , Nacetylserotonin (aHT) , and N-acetyltransferase (NAT) activity levels which were lower than those obtained with alpha-methyldopa treatment alone, thus confirming the alpha-adrenergic activity of the metabolite of alpha-methyldopa. Additional pineal metabolites were isolated and measured simultaneously in the organ culture experiments. Organ cultures of rat pineal glands treated with ephedrine showed raised levels of melatonin (aMT) and N-acetylserotonin (aHT). Treatment with ephedrine also produced raised N-acetyltransferase activity. A further enhancement of these parameters was induced by norepinephrine, suggesting a supersensitivity-type effect occurring at the level of the beta-adrenergic receptor. Rats were treated with reserpine (a norepinephrine depleter) and the pineals exposed to ephedrine. Endogenous norepinephrine normally released by the action of ephedrine was thus absent, and under these conditions, levels of melatonin (aMT) and N-acetylserotonin (aHT) were reduced. N-acetyltransferase (NAT) activity was also reduced, but maintained levels pointing to substantial adrenergic activity of ephedrine as well as norepinephrine released by virtue of the drug's action. A subsequent binding study showed a decrease in beta-adrenergic receptor binding with exposure to ephedrine and a further decrease in ephedrine treated pineals from reserpine treated rats, thus ruling out the occurrence of a supersensitivity phenomenon. It is possible that both ephedrine and released norepinephrine have alpha- and beta-receptor activity. Additional pineal metabolites were isolated and measured in the organ culture experiments. A 16-hour time profile of the production of melatonin (aMT) and N-acetylserotonin (aHT) with norepinephrine and ephedrine treatment provided useful information regarding the course of action of the two agents. A pineal cell-culture system was developed and exposed to ephedrine and norepinephrine. N-acetyltransferase (NAT) activity levels measured after exposure to these agents were raised, confirming the adrenergic activity of both in the model. Finally, an HPLC system coupled to a UV detector was used in an attempt to measure melatonin (aMT) extracted from pineal organ culture media. The results showed that melatonin could be measured by this method, however, a more sensitive detection system was recommended for future work
- Full Text:
- Date Issued: 1991
The precambrian iron-formations in the Limpopo belt as represented by the magnetite quartzite deposits at Moonlight, Koedoesrand area, Northern Transvaal
- Authors: Badenhorst, Jaco Cornelis
- Date: 1991 , 2013-02-20
- Subjects: Iron ores -- Geology -- South Africa , Quartzite -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5064 , http://hdl.handle.net/10962/d1013309
- Description: This dissertation is based largely on data that was accumulated during the execution of an exploration program by Iscor Ltd in the Northern Transvaal. The program included geological mapping, geophysical surveys and drilling, on Precambrian iron-formations in the Central Zone of the Limpopo Belt. The structure, stratigraphy, metamorphism, and economic importance of the magnetite quartzites and associated lithologies of the Moonlight prospect are discussed. The lithologies underlying the Moonlight prospect area consist of various pink- and grey-banded gneisses and pink granulite, together with a variety of metasedimentary supracrustal rock-types and concordant serpentinite bodies. The gneissic rock-types consist of chlorite-quartz-feldspar gneiss, chlorite-quartz-feldspar augen gneiss, hornblende-quartz-feldspar gneiss, biotite-quartz-feldspar gneiss, felsic and mafic granulite, and foliated amphibolite. The metasedimentary lithologies are represented by calc-silicates and marble, white quartz-feldspar granulite, magnetite quartzite, metaquartzite and garnet-bearing granulite and gneiss (metapelites). The concordant ultramafic bodies consist of serpentinite with lesser amphibolite, dunite, and chromitite. Intrusive pegmatites and diabase dykes are also present in the prospect area. Metamorphism reached granulite-facies, and more than one retrqgrade metamorphic event is recognized . Amphibolite-facies assemblages are present, but it is uncertain whether they represent another retrograde event . Polyphase deformation has produced intense and complex folding , resulting in irregular magnetite quartzite orebodies. The high metamorphic grades have resulted in medium- grained recrystallization of the magnetite-quartzites with a loss of prominent banding often associated with these rock-types . The magnetite quartzite occurs as three seperate but related ore zones, consisting of one or more ore-bands seperated by other lithologies. All three zones form poor outcrops and suboutcrops in a generally flat lying and sand covered area. · Although representing a low-grade iron ore (32% total Fe), the magnetite quartzite deposits at Moonlight are regarded as potentially viable due to the large opencast tonnages available at low stripping ratios, and the relatively cheap and easy beneficiation process needed to produce a magnetite concentrate with 69-70% total Fe.
- Full Text:
- Date Issued: 1991
- Authors: Badenhorst, Jaco Cornelis
- Date: 1991 , 2013-02-20
- Subjects: Iron ores -- Geology -- South Africa , Quartzite -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5064 , http://hdl.handle.net/10962/d1013309
- Description: This dissertation is based largely on data that was accumulated during the execution of an exploration program by Iscor Ltd in the Northern Transvaal. The program included geological mapping, geophysical surveys and drilling, on Precambrian iron-formations in the Central Zone of the Limpopo Belt. The structure, stratigraphy, metamorphism, and economic importance of the magnetite quartzites and associated lithologies of the Moonlight prospect are discussed. The lithologies underlying the Moonlight prospect area consist of various pink- and grey-banded gneisses and pink granulite, together with a variety of metasedimentary supracrustal rock-types and concordant serpentinite bodies. The gneissic rock-types consist of chlorite-quartz-feldspar gneiss, chlorite-quartz-feldspar augen gneiss, hornblende-quartz-feldspar gneiss, biotite-quartz-feldspar gneiss, felsic and mafic granulite, and foliated amphibolite. The metasedimentary lithologies are represented by calc-silicates and marble, white quartz-feldspar granulite, magnetite quartzite, metaquartzite and garnet-bearing granulite and gneiss (metapelites). The concordant ultramafic bodies consist of serpentinite with lesser amphibolite, dunite, and chromitite. Intrusive pegmatites and diabase dykes are also present in the prospect area. Metamorphism reached granulite-facies, and more than one retrqgrade metamorphic event is recognized . Amphibolite-facies assemblages are present, but it is uncertain whether they represent another retrograde event . Polyphase deformation has produced intense and complex folding , resulting in irregular magnetite quartzite orebodies. The high metamorphic grades have resulted in medium- grained recrystallization of the magnetite-quartzites with a loss of prominent banding often associated with these rock-types . The magnetite quartzite occurs as three seperate but related ore zones, consisting of one or more ore-bands seperated by other lithologies. All three zones form poor outcrops and suboutcrops in a generally flat lying and sand covered area. · Although representing a low-grade iron ore (32% total Fe), the magnetite quartzite deposits at Moonlight are regarded as potentially viable due to the large opencast tonnages available at low stripping ratios, and the relatively cheap and easy beneficiation process needed to produce a magnetite concentrate with 69-70% total Fe.
- Full Text:
- Date Issued: 1991
The shadowed corners of sunlit ruins: Gothic elements in twentieth century children's adventure fiction
- Authors: Wagenaar, Peter Simon
- Date: 1991
- Subjects: Children's literature -- 20th century -- History and criticism , Gothic literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2250 , http://hdl.handle.net/10962/d1002293 , Children's literature -- 20th century -- History and criticism , Gothic literature
- Description: This thesis examines the way in which children's adventure fiction makes use of Gothic features, how these features have been modified for a younger audience and how these modifications have been influenced by other developments in children's and popular fiction: Chapter One sets out to define the nature of Gothic and isolate those aspects of it relevant to the proposed study. It puts forward a theory to account for the movement of Gothic trends into later children's fiction. Chapter Two examines the use of landscape, setting and atmospheric effects in Gothic and the way in which children's fiction has used similar trappings to create similar effects. Children's fiction, emphasising pleasurable excitement rather than fear has, however, muted these effects somewhat and played down the role of the supernatural, so intrinsic to Gothic. Chapter Three emphasises the Gothic's use of stereotypes, focusing on the portrayal of heroes and heroines. Those of children's fiction are portrayed very similarly to those of Gothic and the chapter compares and, on occasion, contrasts them noting, inter alia, their adherence to rigid moral codes and narrowly defined norms of masculine and feminine behaviour. Chapter Four looks at the portrayal of villains and the way in which their appearance defines them as such (as, indeed, does that of heroes and heroines). It examines in some detail their relationship to and interaction with the heroes and heroines, noting, for example, the 'pseudo-parental' role of villains who are characteristically older and in socially approved positions to exert power over heroes and heroines. The Conclusion addresses the fantasy aspect of these novels,referred to several times in passing in the course of earlier chapters, and comments on how the features detailed in Chapters Two, Three and Four all operate within the conventions of a fantasy.
- Full Text:
- Date Issued: 1991
- Authors: Wagenaar, Peter Simon
- Date: 1991
- Subjects: Children's literature -- 20th century -- History and criticism , Gothic literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2250 , http://hdl.handle.net/10962/d1002293 , Children's literature -- 20th century -- History and criticism , Gothic literature
- Description: This thesis examines the way in which children's adventure fiction makes use of Gothic features, how these features have been modified for a younger audience and how these modifications have been influenced by other developments in children's and popular fiction: Chapter One sets out to define the nature of Gothic and isolate those aspects of it relevant to the proposed study. It puts forward a theory to account for the movement of Gothic trends into later children's fiction. Chapter Two examines the use of landscape, setting and atmospheric effects in Gothic and the way in which children's fiction has used similar trappings to create similar effects. Children's fiction, emphasising pleasurable excitement rather than fear has, however, muted these effects somewhat and played down the role of the supernatural, so intrinsic to Gothic. Chapter Three emphasises the Gothic's use of stereotypes, focusing on the portrayal of heroes and heroines. Those of children's fiction are portrayed very similarly to those of Gothic and the chapter compares and, on occasion, contrasts them noting, inter alia, their adherence to rigid moral codes and narrowly defined norms of masculine and feminine behaviour. Chapter Four looks at the portrayal of villains and the way in which their appearance defines them as such (as, indeed, does that of heroes and heroines). It examines in some detail their relationship to and interaction with the heroes and heroines, noting, for example, the 'pseudo-parental' role of villains who are characteristically older and in socially approved positions to exert power over heroes and heroines. The Conclusion addresses the fantasy aspect of these novels,referred to several times in passing in the course of earlier chapters, and comments on how the features detailed in Chapters Two, Three and Four all operate within the conventions of a fantasy.
- Full Text:
- Date Issued: 1991
The Springfontein prospect : a case study of a tertiary age epithermal hot spring deposit in the Eastern Cape
- Authors: Nichols, Richard Lionel
- Date: 1991
- Subjects: Hot springs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5058 , http://hdl.handle.net/10962/d1012963
- Description: The Springfontein Prospect is a Tertiary aged epithermal Hot Spring deposit that was investigated for precious metal mineralisation. It is located some 14 kilometres due west of East London (Cape Province), within Beaufort Group sediments and Karoo dolerite. Prior to the work described in this case study, the location was known for it's abundant plant fossils and barite mineralisation. A gossan sample collected near the main barite vein returned 1,07 g/t Au and 26,6 g/t Ag. Remote sensing studies of the site revealed a set of north-south lineaments paralleling the barite vein system. Geophysical surveys confirmed this orientation and revealed an extensive alteration system underlying the prominent sinter terrace. A detailed soil geochemical survey returned elevated values in the classical epithermal gold mineralisation element suite (Rg, Tl, As, Bi, Sb, Te, Mo, Ba and Pb - Bonham, 1986). Trenching of geochemical anomalies revealed zones of intense argillic alteration and vein stockworks). Four percussion and three diamond drill holes intersected a 'feeder-fissure' system of veins, alteration and brecciation, but failed to repeat gold levels seen at surface. Mineralogical and petrographic studies of the cores determined temperatures of formation of important indicator minerals (e.g. adularia and zeolites). Litho-geochemical work revealed mercury (and thallium) to be most elevated in the feeder systems. Stratigraphic and paleontological observations determined that the Springfontein Tertiary deposit was clearly different to the other siliceous (silcrete) units that crop out in the Eastern Cape region. A number of distinguished visitors to the prospect, with epithermal deposit experience, confirmed that the characteristics and dimensions of the system is within those of mineralised deposits elsewhere. A brief review of current epithermal models are presented. The conceptual geological model for the Springfontein prospect evolved through the exploration programme. The final consensus is that it best fits Bonham's (1986) alkalic model and the Tertiary epithermal event was sustained by rifting associated with the break-up of Gondwanaland.
- Full Text:
- Date Issued: 1991
- Authors: Nichols, Richard Lionel
- Date: 1991
- Subjects: Hot springs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5058 , http://hdl.handle.net/10962/d1012963
- Description: The Springfontein Prospect is a Tertiary aged epithermal Hot Spring deposit that was investigated for precious metal mineralisation. It is located some 14 kilometres due west of East London (Cape Province), within Beaufort Group sediments and Karoo dolerite. Prior to the work described in this case study, the location was known for it's abundant plant fossils and barite mineralisation. A gossan sample collected near the main barite vein returned 1,07 g/t Au and 26,6 g/t Ag. Remote sensing studies of the site revealed a set of north-south lineaments paralleling the barite vein system. Geophysical surveys confirmed this orientation and revealed an extensive alteration system underlying the prominent sinter terrace. A detailed soil geochemical survey returned elevated values in the classical epithermal gold mineralisation element suite (Rg, Tl, As, Bi, Sb, Te, Mo, Ba and Pb - Bonham, 1986). Trenching of geochemical anomalies revealed zones of intense argillic alteration and vein stockworks). Four percussion and three diamond drill holes intersected a 'feeder-fissure' system of veins, alteration and brecciation, but failed to repeat gold levels seen at surface. Mineralogical and petrographic studies of the cores determined temperatures of formation of important indicator minerals (e.g. adularia and zeolites). Litho-geochemical work revealed mercury (and thallium) to be most elevated in the feeder systems. Stratigraphic and paleontological observations determined that the Springfontein Tertiary deposit was clearly different to the other siliceous (silcrete) units that crop out in the Eastern Cape region. A number of distinguished visitors to the prospect, with epithermal deposit experience, confirmed that the characteristics and dimensions of the system is within those of mineralised deposits elsewhere. A brief review of current epithermal models are presented. The conceptual geological model for the Springfontein prospect evolved through the exploration programme. The final consensus is that it best fits Bonham's (1986) alkalic model and the Tertiary epithermal event was sustained by rifting associated with the break-up of Gondwanaland.
- Full Text:
- Date Issued: 1991
The synthesis of sound with application in a MIDI environment
- Authors: Kesterton, Anthony James
- Date: 1991
- Subjects: Computer sound processing -- Research , Music -- Data processing -- Research , MIDI (Standard)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4678 , http://hdl.handle.net/10962/d1006701 , Computer sound processing -- Research , Music -- Data processing -- Research , MIDI (Standard)
- Description: The wide range of options for experimentation with the synthesis of sound are usually expensive, difficult to obtain, or limit the experimenter. The work described in this thesis shows how the IBM PC and software can be combined to provide a suitable platform for experimentation with different synthesis techniques. This platform is based on the PC, the Musical Instrument Digital Interface (MIDI) and a musical instrument called a digital sampler. The fundamental concepts of sound are described, with reference to digital sound reproduction. A number of synthesis techniques are described. These are evaluated according to the criteria of generality, efficiency and control. The techniques discussed are additive synthesis, frequency modulation synthesis, subtractive synthesis, granular synthesis, resynthesis, wavetable synthesis, and sampling. Spiral synthesis, physical modelling, waveshaping and spectral interpolation are discussed briefly. The Musical Instrument Digital Interface is a standard method of connecting digital musical instruments together. It is the MIDI standard and equipment conforming to that standard that makes this implementation of synthesis techniques possible. As a demonstration of the PC platform, additive synthesis, frequency modulation synthesis, granular synthesis and spiral synthesis have been implemented in software. A PC equipped with a MIDI interface card is used to perform the synthesis. The MIDI protocol is used to transmit the resultant sound to a digital sampler. The INMOS transputer is used as an accelerator, as the calculation of a waveform using software is a computational intensive process. It is concluded that sound synthesis can be performed successfully using a PC and the appropriate software, and utilizing the facilities provided by a MIDI environment including a digital sampler.
- Full Text:
- Date Issued: 1991
- Authors: Kesterton, Anthony James
- Date: 1991
- Subjects: Computer sound processing -- Research , Music -- Data processing -- Research , MIDI (Standard)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4678 , http://hdl.handle.net/10962/d1006701 , Computer sound processing -- Research , Music -- Data processing -- Research , MIDI (Standard)
- Description: The wide range of options for experimentation with the synthesis of sound are usually expensive, difficult to obtain, or limit the experimenter. The work described in this thesis shows how the IBM PC and software can be combined to provide a suitable platform for experimentation with different synthesis techniques. This platform is based on the PC, the Musical Instrument Digital Interface (MIDI) and a musical instrument called a digital sampler. The fundamental concepts of sound are described, with reference to digital sound reproduction. A number of synthesis techniques are described. These are evaluated according to the criteria of generality, efficiency and control. The techniques discussed are additive synthesis, frequency modulation synthesis, subtractive synthesis, granular synthesis, resynthesis, wavetable synthesis, and sampling. Spiral synthesis, physical modelling, waveshaping and spectral interpolation are discussed briefly. The Musical Instrument Digital Interface is a standard method of connecting digital musical instruments together. It is the MIDI standard and equipment conforming to that standard that makes this implementation of synthesis techniques possible. As a demonstration of the PC platform, additive synthesis, frequency modulation synthesis, granular synthesis and spiral synthesis have been implemented in software. A PC equipped with a MIDI interface card is used to perform the synthesis. The MIDI protocol is used to transmit the resultant sound to a digital sampler. The INMOS transputer is used as an accelerator, as the calculation of a waveform using software is a computational intensive process. It is concluded that sound synthesis can be performed successfully using a PC and the appropriate software, and utilizing the facilities provided by a MIDI environment including a digital sampler.
- Full Text:
- Date Issued: 1991