(L, M)-fuzzy topological spaces
- Authors: Matutu, Phethiwe Precious
- Date: 1992
- Subjects: Topological spaces , Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5410 , http://hdl.handle.net/10962/d1005224 , Topological spaces , Fuzzy sets
- Description: The objective of this thesis is to develop certain aspects of the theory of (L,M)-fuzzy topological spaces, where L and M are complete lattices (with additional conditions when necessary). We obtain results which are to a large extent analogous to results given in a series of papers of Šostak (where L = M = [0,1]) but not necessarily with analogous proofs. Often, our generalizations require a variety of techniques from lattice theory e.g. from continuity or complete distributive lattices.
- Full Text:
- Date Issued: 1992
- Authors: Matutu, Phethiwe Precious
- Date: 1992
- Subjects: Topological spaces , Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5410 , http://hdl.handle.net/10962/d1005224 , Topological spaces , Fuzzy sets
- Description: The objective of this thesis is to develop certain aspects of the theory of (L,M)-fuzzy topological spaces, where L and M are complete lattices (with additional conditions when necessary). We obtain results which are to a large extent analogous to results given in a series of papers of Šostak (where L = M = [0,1]) but not necessarily with analogous proofs. Often, our generalizations require a variety of techniques from lattice theory e.g. from continuity or complete distributive lattices.
- Full Text:
- Date Issued: 1992
Power play and the changing face of English
- Authors: De Klerk, Vivian A
- Date: 1992
- Language: English
- Type: Conference paper
- Identifier: vital:6126 , http://hdl.handle.net/10962/d1011599
- Full Text:
- Date Issued: 1992
- Authors: De Klerk, Vivian A
- Date: 1992
- Language: English
- Type: Conference paper
- Identifier: vital:6126 , http://hdl.handle.net/10962/d1011599
- Full Text:
- Date Issued: 1992
The chemistry of a new water-recirculation aquaculture system with emphasis on the influence of ozone on water quality
- Authors: Stobart, Michael David
- Date: 1992
- Subjects: Water quality -- Environmental aspects -- Testing , Ozone -- Physiological effect , Aquatic ecology , Aquaculture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5244 , http://hdl.handle.net/10962/d1005087 , Water quality -- Environmental aspects -- Testing , Ozone -- Physiological effect , Aquatic ecology , Aquaculture
- Description: Water quality changes that occur during establishment and maintenance of nitrification in two identical recirculating aquaculture systems containing rainbow trout are described. The time taken for the nitrification process to become established was 40-45 days. Mortality of fish attributed to elevated nitrite concentrations were recorded during the initial conditioning phase of the systems. Un-ionised ammonia concentrations did not attain lethal levels during this period. Nitrate concentrations accumulated slowly throughout the study, while the pH and alkalinity of the water decreased with progressive nitrification. Levels of carbon dioxide, calcium, dissolved and suspended solids remained relatively stable until the carrying capacity of the systems was increased, upon which they increased rapidly and general water quality deteriorated. Permanently elevated concentrations of ammonia and nitrite served as an indication that the carrying capacity of the systems had been exceeded. The use of ozone as a water enhancement treatment in aquaculture systems during one- and six-hour applications was also considered in this study. Ozonation significantly reduced nitrite levels at · low concentrations (0,1 - 0,15 mg/l), although they returned to pre-treatment levels within a few hours of cessation of the treatment. The formation of an unstable, intermediate product that reforms as nitrite in the absence of ozone, rather than the complete oxidation of nitrite to nitrate, is proposed. Ozonation also resulted in decreased dissolved solids, and improved the clarity and odour of the water. Ozone had no effect on ammonia concentrations (at pH > 7,0), or on nitrate or calcium levels, and did not conclusively increase the redox potential of the water. Residual ozone concentrations up to 0,04 mg/l in a sixhour treatment had no harmful effects on rainbow trout, and there were no signs of gas-bubble disease arising from supersaturation of the water with oxygen. Activated carbon filters were effective at removing residual ozone from the water after treatment. Treatment of the water with oxygen alone had no effect on nitrite concentrations.
- Full Text:
- Date Issued: 1992
- Authors: Stobart, Michael David
- Date: 1992
- Subjects: Water quality -- Environmental aspects -- Testing , Ozone -- Physiological effect , Aquatic ecology , Aquaculture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5244 , http://hdl.handle.net/10962/d1005087 , Water quality -- Environmental aspects -- Testing , Ozone -- Physiological effect , Aquatic ecology , Aquaculture
- Description: Water quality changes that occur during establishment and maintenance of nitrification in two identical recirculating aquaculture systems containing rainbow trout are described. The time taken for the nitrification process to become established was 40-45 days. Mortality of fish attributed to elevated nitrite concentrations were recorded during the initial conditioning phase of the systems. Un-ionised ammonia concentrations did not attain lethal levels during this period. Nitrate concentrations accumulated slowly throughout the study, while the pH and alkalinity of the water decreased with progressive nitrification. Levels of carbon dioxide, calcium, dissolved and suspended solids remained relatively stable until the carrying capacity of the systems was increased, upon which they increased rapidly and general water quality deteriorated. Permanently elevated concentrations of ammonia and nitrite served as an indication that the carrying capacity of the systems had been exceeded. The use of ozone as a water enhancement treatment in aquaculture systems during one- and six-hour applications was also considered in this study. Ozonation significantly reduced nitrite levels at · low concentrations (0,1 - 0,15 mg/l), although they returned to pre-treatment levels within a few hours of cessation of the treatment. The formation of an unstable, intermediate product that reforms as nitrite in the absence of ozone, rather than the complete oxidation of nitrite to nitrate, is proposed. Ozonation also resulted in decreased dissolved solids, and improved the clarity and odour of the water. Ozone had no effect on ammonia concentrations (at pH > 7,0), or on nitrate or calcium levels, and did not conclusively increase the redox potential of the water. Residual ozone concentrations up to 0,04 mg/l in a sixhour treatment had no harmful effects on rainbow trout, and there were no signs of gas-bubble disease arising from supersaturation of the water with oxygen. Activated carbon filters were effective at removing residual ozone from the water after treatment. Treatment of the water with oxygen alone had no effect on nitrite concentrations.
- Full Text:
- Date Issued: 1992
Form and substance in R.M. Hare's utilitarianism
- Authors: Coetzee, Pieter Hendrik
- Date: 1992
- Subjects: Hare, R. M. (Richard Mervyn) -- Ethics , Utilitarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2706 , http://hdl.handle.net/10962/d1002836 , Hare, R. M. (Richard Mervyn) -- Ethics , Utilitarianism
- Description: Throughout his career as moral philosopher Hare has insisted that there is a rational way of arriving at substantive moral judgements. Hare develops this view - first presented in ' The language of morals' (1952) and ' Universalizability' (1955) - into the claim that rational agents are required to adopt utilitarian solutions to moral disputes. In ' Freedom and reason ' (1963) this claim is defended with reference to the view that the formal features of moral language (universalizability and prescriptivity)commit moral agents to a certain method of reasoning, and that this method of reasoning, when conjoined with facts about people's desires and preferences, leads us to accept substantive moral judgements consistent with those required by a form of utilitarianism. This view features throughout Hare's subsequent work, but the argument for it undergoes change. This means change in the defence of the claim that the meta-theory Universal Prescriptivism is consistent with a form of normative utilitarian theory, as this claim is argued for in 'Ethical theory and utilitarianism' (1976) and 'Moral Thinking' (1981). I shall endeavour to trace the chronological development of Hare's thinking, and will concentrate on developments in the argument for a theory of act-utilitarianism. I shall argue that the argument for utilitarianism gives rise to two major problems which arise from a specific feature of the argument, namely, the attempt to run the resolution of bi-lateral and multi-lateral cases of conflict along lines analogous to the resolution of conflict in the single-person case. Hare's argument requires that a decision-maker must identify the person with whom he reverses roles as himself, and that he must be prepared to concede that the things his recipient has good reasons for wanting are also reasons for him to want the same things. I argue that it is not possible to make coherent sense of the identity of the person in the reversed-role situation and that the motivational states a decision -maker is expected to deem 'his own' are not properly states of himself. If I am right, the 'identity'-question sits at the root of a motivational gap in Hare's theory.
- Full Text:
- Date Issued: 1992
- Authors: Coetzee, Pieter Hendrik
- Date: 1992
- Subjects: Hare, R. M. (Richard Mervyn) -- Ethics , Utilitarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2706 , http://hdl.handle.net/10962/d1002836 , Hare, R. M. (Richard Mervyn) -- Ethics , Utilitarianism
- Description: Throughout his career as moral philosopher Hare has insisted that there is a rational way of arriving at substantive moral judgements. Hare develops this view - first presented in ' The language of morals' (1952) and ' Universalizability' (1955) - into the claim that rational agents are required to adopt utilitarian solutions to moral disputes. In ' Freedom and reason ' (1963) this claim is defended with reference to the view that the formal features of moral language (universalizability and prescriptivity)commit moral agents to a certain method of reasoning, and that this method of reasoning, when conjoined with facts about people's desires and preferences, leads us to accept substantive moral judgements consistent with those required by a form of utilitarianism. This view features throughout Hare's subsequent work, but the argument for it undergoes change. This means change in the defence of the claim that the meta-theory Universal Prescriptivism is consistent with a form of normative utilitarian theory, as this claim is argued for in 'Ethical theory and utilitarianism' (1976) and 'Moral Thinking' (1981). I shall endeavour to trace the chronological development of Hare's thinking, and will concentrate on developments in the argument for a theory of act-utilitarianism. I shall argue that the argument for utilitarianism gives rise to two major problems which arise from a specific feature of the argument, namely, the attempt to run the resolution of bi-lateral and multi-lateral cases of conflict along lines analogous to the resolution of conflict in the single-person case. Hare's argument requires that a decision-maker must identify the person with whom he reverses roles as himself, and that he must be prepared to concede that the things his recipient has good reasons for wanting are also reasons for him to want the same things. I argue that it is not possible to make coherent sense of the identity of the person in the reversed-role situation and that the motivational states a decision -maker is expected to deem 'his own' are not properly states of himself. If I am right, the 'identity'-question sits at the root of a motivational gap in Hare's theory.
- Full Text:
- Date Issued: 1992
56 years old and growing : Geography
- Authors: Lewis, Colin A
- Date: 1992
- Language: English
- Type: Article
- Identifier: vital:6708 , http://hdl.handle.net/10962/d1006745
- Description: This article traces the growth and development of the Rhodes University Geography Department from 1936 to 1992, the academic staff and students associated with it, and the research emanating from it.
- Full Text: false
- Date Issued: 1992
- Authors: Lewis, Colin A
- Date: 1992
- Language: English
- Type: Article
- Identifier: vital:6708 , http://hdl.handle.net/10962/d1006745
- Description: This article traces the growth and development of the Rhodes University Geography Department from 1936 to 1992, the academic staff and students associated with it, and the research emanating from it.
- Full Text: false
- Date Issued: 1992
Up Beat Issue Number 2 1992
- SACHED
- Authors: SACHED
- Date: 1992
- Subjects: SACHED
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/116190 , vital:34331
- Description: Teenage life is full of challenges.’ That’s what Ebrahim Abader from Cape Town thinks. He’s right. When you are young there is lots to learn and discover about yourself and the big world out there. It's exciting! But it can be a miserable time too. It is not easy to meet a challenge when you are worried about pimples, can’t do your maths and are suffering from a broken heart. You are special but you are not alone. Young people all over the world are probably going through what you are. Believe it or not your parents and teachers where once teenagers too. Ask them what it was like. There is a big challenge facing all of us, especially young people in South Africa today. We have to learn to live together; to accept differences and respect one another’s feelings and beliefs. It is called tolerance! Your parents, brothers, sisters, comrades, neighbours and friends have their own ideas. Listen to them with an open mind. In this issue you can read about a great school in Tongaat in Natal. Here students have learnt to forget about colour and together are discovering what real learning is all about. Meet Simon Nkoli. He knows what it’s like to be treated unfairly and to grow up feeling different and alone. So readers, speak out, listen, read and learn. That’s the way to get wise. That’s the way to meet the challenge of being a teenager in South Africa today. Some of you may be writing supplementary exams. Go for it - you can do it this time! We are holding thumbs.
- Full Text:
- Date Issued: 1992
- Authors: SACHED
- Date: 1992
- Subjects: SACHED
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/116190 , vital:34331
- Description: Teenage life is full of challenges.’ That’s what Ebrahim Abader from Cape Town thinks. He’s right. When you are young there is lots to learn and discover about yourself and the big world out there. It's exciting! But it can be a miserable time too. It is not easy to meet a challenge when you are worried about pimples, can’t do your maths and are suffering from a broken heart. You are special but you are not alone. Young people all over the world are probably going through what you are. Believe it or not your parents and teachers where once teenagers too. Ask them what it was like. There is a big challenge facing all of us, especially young people in South Africa today. We have to learn to live together; to accept differences and respect one another’s feelings and beliefs. It is called tolerance! Your parents, brothers, sisters, comrades, neighbours and friends have their own ideas. Listen to them with an open mind. In this issue you can read about a great school in Tongaat in Natal. Here students have learnt to forget about colour and together are discovering what real learning is all about. Meet Simon Nkoli. He knows what it’s like to be treated unfairly and to grow up feeling different and alone. So readers, speak out, listen, read and learn. That’s the way to get wise. That’s the way to meet the challenge of being a teenager in South Africa today. Some of you may be writing supplementary exams. Go for it - you can do it this time! We are holding thumbs.
- Full Text:
- Date Issued: 1992
A microstructural kinematic study of selected shear zones in the Hartbees River Thrust Belt, northeastern Namaqua Tectonic Province
- Authors: Jackson, Christopher
- Date: 1992
- Subjects: Metamorphic rocks -- South Africa -- Northern Cape , Mylonite -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4976 , http://hdl.handle.net/10962/d1005588 , Metamorphic rocks -- South Africa -- Northern Cape , Mylonite -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Description: The Hartbees River Thrust Belt (HRTS) is a 40-60 km wide, southwest-vergent zone of complex structure, lithostratigraphy and high-grade metamorphism in the northeastern part of the mid-Proterozoic Namaqua Tectonic Province. The HRTS comprises the boundary zone separating the Bushmanland and Gordonia Subprovinces of the Namaqua Province. A knowledge of the movement histories of major ductile shear zones within the HRTS is fundamental to understanding the tectonic development of the belt, and Namaqua tectogenesis as a whole. In spite of this, no detailed microstructural kinematic studies have been attempted and the movement histories and age relationships of these shear zones have not been described in detail. This thesis represents a detailed microstructural kinematic study of a representative suite of orientated samples of mylonitic rocks, collected from five ductile shear zones within the HRTS. These shear zones include the Neusspruit Lineament, the Kakamas shear zone (KSZ), the Hugosput shear system (HSS), the Rozynenbosch-Ganzenmond shear zone (RGSZ) and the Graafwater shear system (GSS). Accepted modern methods of microstructural kinematic analysis were applied to samples of mylonite from these shear zones, in order to determine the precise orientation of the kinematic vectors, and the sense and relative ages of movements on each of the shear zones. Shear sense criteria, including composite SoC planar fabrics and shear band foliations, asymmetrical porphyroclast systems, mica-fish, oblique grain-shape and subgrain fabrics, asymmetrical microfolds, and the displacement of fractured rigid grains, together with a well-developed mylonite elongation lineation, conclusively indicate that SSW-directed thrusting occurred along the HSS, RGSZ, GSS and possibly along the Neusspruit Lineament, while normal, top-to-NE movements occurred on the Neusspruit Lineament, KSZ and HSS. Rare transposition criteria, and textural and paragenetic contrasts between syn-kinematic fabrics, strongly suggest that the phase of normal, top-to-NE movement seen in the northeastern HRTS shear zones is younger than the more widespread top-to-SW thrusting event. On the basis of mesoscopic structural criteria, SSW-directed thrusting is correlated with the D₂ deformation event in the HRTS. The mylonite zones have been refolded by ENE-SSW trending F₃ crossfolds, whose demonstrated coaxial relationship to the mylonite elongation lineation precluded reorientation of primary kinematic vectors. In the southwestern HRTS, primary thrust vectors have been reoriented by right-lateral, strike-slip shearing adjacent to the Pofadder Lineament during D₄. Simple shear dispersion of mylonite lineations related to normal movement, suggests that they too have been modified by D₄ shearing, and this constrains the timing of extensional movements to post-D₂ and pre- or syn-D₄. Syn-kinematic mineral assemblages, rheological criteria and the annealing states of the mylonites, provide insight into the thermotectonic evolution of the shear zones. A model is proposed in which the movement histories of shear zones within the HRTS are explained in terms of a typical orogenic cycle, involving crustal thickening by thrusting during a compressional orogenic phase, followed by collapse of the thickened crust during an extensional taphrogenic phase.
- Full Text:
- Date Issued: 1992
- Authors: Jackson, Christopher
- Date: 1992
- Subjects: Metamorphic rocks -- South Africa -- Northern Cape , Mylonite -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4976 , http://hdl.handle.net/10962/d1005588 , Metamorphic rocks -- South Africa -- Northern Cape , Mylonite -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Description: The Hartbees River Thrust Belt (HRTS) is a 40-60 km wide, southwest-vergent zone of complex structure, lithostratigraphy and high-grade metamorphism in the northeastern part of the mid-Proterozoic Namaqua Tectonic Province. The HRTS comprises the boundary zone separating the Bushmanland and Gordonia Subprovinces of the Namaqua Province. A knowledge of the movement histories of major ductile shear zones within the HRTS is fundamental to understanding the tectonic development of the belt, and Namaqua tectogenesis as a whole. In spite of this, no detailed microstructural kinematic studies have been attempted and the movement histories and age relationships of these shear zones have not been described in detail. This thesis represents a detailed microstructural kinematic study of a representative suite of orientated samples of mylonitic rocks, collected from five ductile shear zones within the HRTS. These shear zones include the Neusspruit Lineament, the Kakamas shear zone (KSZ), the Hugosput shear system (HSS), the Rozynenbosch-Ganzenmond shear zone (RGSZ) and the Graafwater shear system (GSS). Accepted modern methods of microstructural kinematic analysis were applied to samples of mylonite from these shear zones, in order to determine the precise orientation of the kinematic vectors, and the sense and relative ages of movements on each of the shear zones. Shear sense criteria, including composite SoC planar fabrics and shear band foliations, asymmetrical porphyroclast systems, mica-fish, oblique grain-shape and subgrain fabrics, asymmetrical microfolds, and the displacement of fractured rigid grains, together with a well-developed mylonite elongation lineation, conclusively indicate that SSW-directed thrusting occurred along the HSS, RGSZ, GSS and possibly along the Neusspruit Lineament, while normal, top-to-NE movements occurred on the Neusspruit Lineament, KSZ and HSS. Rare transposition criteria, and textural and paragenetic contrasts between syn-kinematic fabrics, strongly suggest that the phase of normal, top-to-NE movement seen in the northeastern HRTS shear zones is younger than the more widespread top-to-SW thrusting event. On the basis of mesoscopic structural criteria, SSW-directed thrusting is correlated with the D₂ deformation event in the HRTS. The mylonite zones have been refolded by ENE-SSW trending F₃ crossfolds, whose demonstrated coaxial relationship to the mylonite elongation lineation precluded reorientation of primary kinematic vectors. In the southwestern HRTS, primary thrust vectors have been reoriented by right-lateral, strike-slip shearing adjacent to the Pofadder Lineament during D₄. Simple shear dispersion of mylonite lineations related to normal movement, suggests that they too have been modified by D₄ shearing, and this constrains the timing of extensional movements to post-D₂ and pre- or syn-D₄. Syn-kinematic mineral assemblages, rheological criteria and the annealing states of the mylonites, provide insight into the thermotectonic evolution of the shear zones. A model is proposed in which the movement histories of shear zones within the HRTS are explained in terms of a typical orogenic cycle, involving crustal thickening by thrusting during a compressional orogenic phase, followed by collapse of the thickened crust during an extensional taphrogenic phase.
- Full Text:
- Date Issued: 1992
Assessment of the profit sharing schemes
- NUM
- Authors: NUM
- Date: 1992
- Subjects: NUM
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/149616 , vital:38869
- Description: In 1991 and 1992, the NUM accepted basic wage Increases on the gold mines that were far below the annual Inflation rate because of the crisis in the industry. The priority of the union was to preserve employment. But this left the door wide open for rich mines (like Kloof, Elandsrand and Vaal Reefs) to hide behind the low increases that are set in the Chamber negotiations at levels that Freegold, Buffelsfontein and marginal mines can live with. The NUM decided that workers need a way of adding more money onto their wages If the mines can afford to pay more.
- Full Text:
- Date Issued: 1992
- Authors: NUM
- Date: 1992
- Subjects: NUM
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/149616 , vital:38869
- Description: In 1991 and 1992, the NUM accepted basic wage Increases on the gold mines that were far below the annual Inflation rate because of the crisis in the industry. The priority of the union was to preserve employment. But this left the door wide open for rich mines (like Kloof, Elandsrand and Vaal Reefs) to hide behind the low increases that are set in the Chamber negotiations at levels that Freegold, Buffelsfontein and marginal mines can live with. The NUM decided that workers need a way of adding more money onto their wages If the mines can afford to pay more.
- Full Text:
- Date Issued: 1992
Benthic assemblage structure, and the feeding biology of sixteen macroinvertebrate taxa from the Buffalo River, Eastern Cape, South Africa
- Authors: Palmer, Carolyn Gay
- Date: 1992
- Subjects: Aquatic invertebrates -- South Africa -- Eastern Cape Benthos -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5646 , http://hdl.handle.net/10962/d1005328
- Description: The River continuum concept (RCC) (Vannote et al. 1980) attempted to provide a unifying theory of river function. The Functional Feeding Group (FFG) concept (Cummins 1973, 1974) became a major component of the RCC. The FFG concept provides testable hypotheses about the changes in proportions of FFGs along a downstream gradient in a river, in response to the changing nature of food resources. The following short-comings of the FFG concept have been identified: 1) the variability of macroinvertebrate feeding, 2) problems with gut analysis as a method for assigning taxa to FFGs, and 3) inconsistent criteria defining FFGs. The objective of this study was to investigate the macroinvertebrate fauna of the Buffalo River in order to assess the applicability of aspects of the RCC and the FFG concept. The specific aims of the study were: 1) to describe the distribution of macroinvertebrate assemblages in the Buffalo River; 2) to clarify aspects of the FFG concept listed above; 3) to establish whether selected taxa could be assigned to FFGs; 4) to assess whether the proportions of different FFGs in successive reaches of a southern African river conformed to the predictions of the RCC; and 5) to test whether a functional classification is a useful alternative to a taxonomic classification. Macroinvertebrates were collected seasonally from a variety of biotopes at three sites, one each in the upper, middle and lower reaches. Riffles were sampled in summer at 16 sites. Over 100 taxa were identified and an hierarchical classification was prepared using two-way indicator species analysis. Invertebrate assemblages in the narrow headwater stream were taxonomically distinct from those of the middle/lower reaches and were not positively associated with subjectively identified biotopes. Biotopes were characterised by distinct assemblages in the wider middle/lower reaches. Sixteen abundant taxa whose feeding had not been previously investigated were selected for feeding studies, four from the headwaters and 12 from the middle/lower reaches. Methods used included gut content analysis, behavioural observations, food choice experiments and morphological studies using scanning electron microscopy. Three aspects of the functional feeding group concept were clarified. 1) Dietary variability was assessed using gut contents as an index of diet. The gut contents of both early (small) and late (large) instar larvae of all 16 taxa collected from different sites and biotopes, and in different seasons were compared using a multifactor analysis of variance. For all taxa the most consistently significant differences in gut contents were between large and small larvae. These were due to differences in the amount of material in the gut and in varying amounts of rarer dietary items. Dietary variability did not prevent taxa from being assigned to FFGs. 2) Gut content analysis satisfactorily provided basic information about the feeding biology of taxa but proved to be an inadequate single method for positively assigning taxa to FFGs. 3) Before taxa could be assigned to FFGs the definitions for some FFG categories had to be described clearly. It is suggested that the term shredder be based on the observation of shredding and a predominance of leaf fragments in the foregut. The presence of algae was not diagnostic of scrapers and a morphological basis is suggested. A morphological basis for the brusher FFG is described for the first time. All 16 taxa were assigned to FFGs. Three headwater taxa were shredders ((Goerodes caffrariae (Lepidostomatidae), Dyschimus ensifer (Pisulidae), Afronemoura spp. (Notonemouridae)) and one was a collector:brusher (Adenophlebia auriculata (Leptophlebiidae). These results were consistent with RCC predictions. All 12 of the taxa from the middle/lower reaches were filterers or collectors and this result was also consistent with RCC predictions. The Hydropsychidae, Cheumtopsyche afra and Macrostemum capense, were passive net filterers; Neurocaenis reticulatus (Tricorythidae) was a passive setal filterer; Caenidae sp. Band Pseudocloeon maculosum (Baetidae) were active filterers; caenidae sp. A, and the Baetidae, Baetis harrisoni, Centroptilum excisum and Cloeon africanum, were collector: gatherers; the Leptophlebiidae, Choroterpes elegans and Choroterpes nigrescens, were collector:brushers; and Afronurus harrisoni (Heptageniidae) was a scraper. Gut content analyses alone were insufficient to assign taxa to FFGs, but when augmented by morphological and/or behavioural data, taxa could be assigned to FFGs with confidence. In all cases the FFG designation referred to the most frequent style of feeding. N. reticulatus, A. harrisoni and A. auriculata were particularly flexible in their feeding behaviour. A functional classification of macro invertebrates in the Buffalo River was compared with a taxonomic classification. In both cases similar groups were identified, but their taxonomic and functional descriptions yielded different information. It is suggested that functional and taxonomic classifications should be viewed as complementary rather than alternative options.
- Full Text:
- Date Issued: 1992
- Authors: Palmer, Carolyn Gay
- Date: 1992
- Subjects: Aquatic invertebrates -- South Africa -- Eastern Cape Benthos -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5646 , http://hdl.handle.net/10962/d1005328
- Description: The River continuum concept (RCC) (Vannote et al. 1980) attempted to provide a unifying theory of river function. The Functional Feeding Group (FFG) concept (Cummins 1973, 1974) became a major component of the RCC. The FFG concept provides testable hypotheses about the changes in proportions of FFGs along a downstream gradient in a river, in response to the changing nature of food resources. The following short-comings of the FFG concept have been identified: 1) the variability of macroinvertebrate feeding, 2) problems with gut analysis as a method for assigning taxa to FFGs, and 3) inconsistent criteria defining FFGs. The objective of this study was to investigate the macroinvertebrate fauna of the Buffalo River in order to assess the applicability of aspects of the RCC and the FFG concept. The specific aims of the study were: 1) to describe the distribution of macroinvertebrate assemblages in the Buffalo River; 2) to clarify aspects of the FFG concept listed above; 3) to establish whether selected taxa could be assigned to FFGs; 4) to assess whether the proportions of different FFGs in successive reaches of a southern African river conformed to the predictions of the RCC; and 5) to test whether a functional classification is a useful alternative to a taxonomic classification. Macroinvertebrates were collected seasonally from a variety of biotopes at three sites, one each in the upper, middle and lower reaches. Riffles were sampled in summer at 16 sites. Over 100 taxa were identified and an hierarchical classification was prepared using two-way indicator species analysis. Invertebrate assemblages in the narrow headwater stream were taxonomically distinct from those of the middle/lower reaches and were not positively associated with subjectively identified biotopes. Biotopes were characterised by distinct assemblages in the wider middle/lower reaches. Sixteen abundant taxa whose feeding had not been previously investigated were selected for feeding studies, four from the headwaters and 12 from the middle/lower reaches. Methods used included gut content analysis, behavioural observations, food choice experiments and morphological studies using scanning electron microscopy. Three aspects of the functional feeding group concept were clarified. 1) Dietary variability was assessed using gut contents as an index of diet. The gut contents of both early (small) and late (large) instar larvae of all 16 taxa collected from different sites and biotopes, and in different seasons were compared using a multifactor analysis of variance. For all taxa the most consistently significant differences in gut contents were between large and small larvae. These were due to differences in the amount of material in the gut and in varying amounts of rarer dietary items. Dietary variability did not prevent taxa from being assigned to FFGs. 2) Gut content analysis satisfactorily provided basic information about the feeding biology of taxa but proved to be an inadequate single method for positively assigning taxa to FFGs. 3) Before taxa could be assigned to FFGs the definitions for some FFG categories had to be described clearly. It is suggested that the term shredder be based on the observation of shredding and a predominance of leaf fragments in the foregut. The presence of algae was not diagnostic of scrapers and a morphological basis is suggested. A morphological basis for the brusher FFG is described for the first time. All 16 taxa were assigned to FFGs. Three headwater taxa were shredders ((Goerodes caffrariae (Lepidostomatidae), Dyschimus ensifer (Pisulidae), Afronemoura spp. (Notonemouridae)) and one was a collector:brusher (Adenophlebia auriculata (Leptophlebiidae). These results were consistent with RCC predictions. All 12 of the taxa from the middle/lower reaches were filterers or collectors and this result was also consistent with RCC predictions. The Hydropsychidae, Cheumtopsyche afra and Macrostemum capense, were passive net filterers; Neurocaenis reticulatus (Tricorythidae) was a passive setal filterer; Caenidae sp. Band Pseudocloeon maculosum (Baetidae) were active filterers; caenidae sp. A, and the Baetidae, Baetis harrisoni, Centroptilum excisum and Cloeon africanum, were collector: gatherers; the Leptophlebiidae, Choroterpes elegans and Choroterpes nigrescens, were collector:brushers; and Afronurus harrisoni (Heptageniidae) was a scraper. Gut content analyses alone were insufficient to assign taxa to FFGs, but when augmented by morphological and/or behavioural data, taxa could be assigned to FFGs with confidence. In all cases the FFG designation referred to the most frequent style of feeding. N. reticulatus, A. harrisoni and A. auriculata were particularly flexible in their feeding behaviour. A functional classification of macro invertebrates in the Buffalo River was compared with a taxonomic classification. In both cases similar groups were identified, but their taxonomic and functional descriptions yielded different information. It is suggested that functional and taxonomic classifications should be viewed as complementary rather than alternative options.
- Full Text:
- Date Issued: 1992
Mabandla
- Venancio Mbande and his Chopi timbila xylophone group, Tracey, Andrew T N
- Authors: Venancio Mbande and his Chopi timbila xylophone group , Tracey, Andrew T N
- Date: 1992
- Subjects: Chopi (African people) -- South Africa , Folk music , Xylophone music , Rattle (Musical instrument) , Drum (Musical instrument) , Africa South Africa Rustenburg f-sa
- Language: Chopi
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/96531 , vital:31291 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC049b-05
- Description: Traditional dance song accompanied by timbila xylophone rattles and one drum
- Full Text: false
- Date Issued: 1992
- Authors: Venancio Mbande and his Chopi timbila xylophone group , Tracey, Andrew T N
- Date: 1992
- Subjects: Chopi (African people) -- South Africa , Folk music , Xylophone music , Rattle (Musical instrument) , Drum (Musical instrument) , Africa South Africa Rustenburg f-sa
- Language: Chopi
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/96531 , vital:31291 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC049b-05
- Description: Traditional dance song accompanied by timbila xylophone rattles and one drum
- Full Text: false
- Date Issued: 1992
Genetic models for epithermal gold deposits and applications to exploration
- Authors: Veselinović, Milica
- Date: 1992
- Subjects: Gold ores -- Geology , Hydrothermal deposits
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4950 , http://hdl.handle.net/10962/d1005562 , Gold ores -- Geology , Hydrothermal deposits
- Description: Epithermal gold deposits are the product of large-scale hydrothermal systems in tectonically active regions. They form at shallow crustal levels where the physico-chemical conditions change abruptly. Two major groups of epithermal gold deposits can be distinguished based on their genetic connection with: A) Copper-molybdenum porphyry systems and B) Geothermal systems related to volcanic centres and calderas. Epithermal gold deposits connected with geothermal systems encompass three major types: adularia-sericite, acid-sulphate and disseminated replacement (the Carlin-type). Their essential ingredients are: high heat source which leads to convection of groundwater in the upper crust; source of hydrothermal fluid, metals and reduced sulphur; and high-permeability structures which allow fluid convection and metal deposition. Mixing of these ingredients leads to the formation of epithermal gold deposits throughout crustal history, without any restriction on age. The ores were deposited from near-neutral (adularia-sericite type and some of the Carlin-type) to acidic (acid-sulphate type and porphyry-related epithermal gold deposits), low-salinity, high C0₂ and high H₂S fluids, which were predominantly meteoritic in origin. The transport capability of deep fluids in epithermal hydrothermal systems may be shown to be dependent largely on their H₂S content and, through a series of fluid mineral equilibria, on temperature and on C0₂ content. The most common mechanisms of ore deposition are boiling (phase separation), mixing of fluids of different temperatures and salinities, reaction between them and wall rocks, dilution and cooling. An understanding of genetic models for epithermal gold deposits provides the basis for the selection of favourable areas for regional to prospect-scale exploration.
- Full Text:
- Date Issued: 1992
- Authors: Veselinović, Milica
- Date: 1992
- Subjects: Gold ores -- Geology , Hydrothermal deposits
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4950 , http://hdl.handle.net/10962/d1005562 , Gold ores -- Geology , Hydrothermal deposits
- Description: Epithermal gold deposits are the product of large-scale hydrothermal systems in tectonically active regions. They form at shallow crustal levels where the physico-chemical conditions change abruptly. Two major groups of epithermal gold deposits can be distinguished based on their genetic connection with: A) Copper-molybdenum porphyry systems and B) Geothermal systems related to volcanic centres and calderas. Epithermal gold deposits connected with geothermal systems encompass three major types: adularia-sericite, acid-sulphate and disseminated replacement (the Carlin-type). Their essential ingredients are: high heat source which leads to convection of groundwater in the upper crust; source of hydrothermal fluid, metals and reduced sulphur; and high-permeability structures which allow fluid convection and metal deposition. Mixing of these ingredients leads to the formation of epithermal gold deposits throughout crustal history, without any restriction on age. The ores were deposited from near-neutral (adularia-sericite type and some of the Carlin-type) to acidic (acid-sulphate type and porphyry-related epithermal gold deposits), low-salinity, high C0₂ and high H₂S fluids, which were predominantly meteoritic in origin. The transport capability of deep fluids in epithermal hydrothermal systems may be shown to be dependent largely on their H₂S content and, through a series of fluid mineral equilibria, on temperature and on C0₂ content. The most common mechanisms of ore deposition are boiling (phase separation), mixing of fluids of different temperatures and salinities, reaction between them and wall rocks, dilution and cooling. An understanding of genetic models for epithermal gold deposits provides the basis for the selection of favourable areas for regional to prospect-scale exploration.
- Full Text:
- Date Issued: 1992
Applicability of the SERVQUAL instrument under South African conditions : an assessment of four situations
- Authors: Pitt, Leyland Frederick
- Date: 1992
- Subjects: SERVQUAL instrument , Customer service , Measurement , Service quality , South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1160 , http://hdl.handle.net/10962/d1001627
- Description: On-going research in recent years has shown quality of product and service, as perceived by customer, relative to competition, to be the single most important factor contributing to organizational well-being. Quality of product and service also presents one of the most significant opportunities for corporate differentiation. A major requirement for the successful management of quality is therefore effective measurement. In the case of physical goods, progress has been made over a long period. However, in the case of services, real advances have only occurred within the past decade. The importance of service quality is also highlighted by the fact that most businesses today are losing customers due to its inadequacy, rather than poor products. Indeed, from the customer's point of view, services and products probably do not exist in a dichotomy, but, rather, along a spectrum. Therefore, the measurement of service quality is critical, not only in traditional service organizations, but in manufacturing situations as well. The development of the SERVQUAL questionnaire in 1988, offered researchers, perhaps for the first time, an apparently reliable and valid instrument for the measurement of service quality. However, to date the instrument has not been subjected to rigorous testing for reliability and validity in South Africa, across a range of service organizations, within a typology. In this study, the SERVQUAL instrument was used to measure service quality across a range of firms within the Larsson-Bowen contingency framework, under South African conditions. Its main objectives were to assess its reliability and validity in these circumstances. It was found that SERVQUAL performed well across all organizations within the Larsson-Bowen framework, under South African conditions, with regard to reliability, convergent and nomological validity. Its construct validity proved to be less sound, and it was not found to possess discriminant validity. It is suggested that this is less attributable to South African circumstances than to the nature of the organizations. In cases of low diversity of demand, the instrument appears to capture the essence of service quality less effectively. Means of overcoming this in future studies are suggested, as well as other directions for research in the area of service quality measurement
- Full Text:
- Date Issued: 1992
- Authors: Pitt, Leyland Frederick
- Date: 1992
- Subjects: SERVQUAL instrument , Customer service , Measurement , Service quality , South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1160 , http://hdl.handle.net/10962/d1001627
- Description: On-going research in recent years has shown quality of product and service, as perceived by customer, relative to competition, to be the single most important factor contributing to organizational well-being. Quality of product and service also presents one of the most significant opportunities for corporate differentiation. A major requirement for the successful management of quality is therefore effective measurement. In the case of physical goods, progress has been made over a long period. However, in the case of services, real advances have only occurred within the past decade. The importance of service quality is also highlighted by the fact that most businesses today are losing customers due to its inadequacy, rather than poor products. Indeed, from the customer's point of view, services and products probably do not exist in a dichotomy, but, rather, along a spectrum. Therefore, the measurement of service quality is critical, not only in traditional service organizations, but in manufacturing situations as well. The development of the SERVQUAL questionnaire in 1988, offered researchers, perhaps for the first time, an apparently reliable and valid instrument for the measurement of service quality. However, to date the instrument has not been subjected to rigorous testing for reliability and validity in South Africa, across a range of service organizations, within a typology. In this study, the SERVQUAL instrument was used to measure service quality across a range of firms within the Larsson-Bowen contingency framework, under South African conditions. Its main objectives were to assess its reliability and validity in these circumstances. It was found that SERVQUAL performed well across all organizations within the Larsson-Bowen framework, under South African conditions, with regard to reliability, convergent and nomological validity. Its construct validity proved to be less sound, and it was not found to possess discriminant validity. It is suggested that this is less attributable to South African circumstances than to the nature of the organizations. In cases of low diversity of demand, the instrument appears to capture the essence of service quality less effectively. Means of overcoming this in future studies are suggested, as well as other directions for research in the area of service quality measurement
- Full Text:
- Date Issued: 1992
Phenology of the important coleopterous pests of pine forests in the Western Cape, South Africa
- Authors: Tribe, Geoffrey Darryl
- Date: 1992
- Subjects: Beetles -- South Africa Bark beetles -- South Africa -- Cape of Good Hope Scolytidae Phenology -- South Africa Phenology -- South Africa -- Cape of Good Hope
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5737 , http://hdl.handle.net/10962/d1005423
- Description: The phenology of the three exotic pine bark beetles present in South Africa was determined in the south-western Cape Province. Results from weekly trapping of adult beetles using trap-logs over a period of five years showed that the different species had activity peaks at different times of the year. Hylastes angustatus was the most consistent with 95% of the beetles captured in September and October. The Orthotomicus erosus activity peak was more variable but always occurred in the summer months (October to February) when 84% of the beetles were captured. Hylurgus ligniperda was the most variable, being found in every month of the year, although an autumn peak representing 37% of the beetles occurred in April/May. Activity peaks of each species coincided with distinct climatic conditions. Buried and partially-buried pine logs placed vertically in the soil to simulate roots and stems of seedlings were used to determine the colonisation sites of the three bark beetle species. Ninety-eight percent of O. erosus beetles were found in the protruding parts of the logs while 86% of H. ligniperda beetles were found mainly below soil level. H. angustatus were intermediate, entering the logs at or just below the soil interface but colonising mainly the buried parts in which 64% of the beetles were found. Both H. angustatus and H. ligniperda were able to detect and colonise logs buried horizontally at depths of 400mm, but O. erosus beetles were unable to do so. For adequate protection of seedlings from bark beetles, insecticide should be applied to both stems and roots. The phenology of the indigenous pine needle feeders Oosomus varius (Curculionidae) and Prasoidea sericea (Chrysomelidae) was determined by counting, at weekly intervals, the number of beetles present on 10 young pine trees. The O. varius activity peak occurred in August where 42% of all beetles were active, with 87% of the beetles present in July, August and September. P. sericea also had their activity peak in August when 60% of all beetles were active, but with August and September alone accounting for 87% of the beetles. The occurrence of the activity peaks was consistent each year over the five-year study period. This information facilitates the correct timing of prophylactic insecticide sprays.
- Full Text:
- Date Issued: 1992
- Authors: Tribe, Geoffrey Darryl
- Date: 1992
- Subjects: Beetles -- South Africa Bark beetles -- South Africa -- Cape of Good Hope Scolytidae Phenology -- South Africa Phenology -- South Africa -- Cape of Good Hope
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5737 , http://hdl.handle.net/10962/d1005423
- Description: The phenology of the three exotic pine bark beetles present in South Africa was determined in the south-western Cape Province. Results from weekly trapping of adult beetles using trap-logs over a period of five years showed that the different species had activity peaks at different times of the year. Hylastes angustatus was the most consistent with 95% of the beetles captured in September and October. The Orthotomicus erosus activity peak was more variable but always occurred in the summer months (October to February) when 84% of the beetles were captured. Hylurgus ligniperda was the most variable, being found in every month of the year, although an autumn peak representing 37% of the beetles occurred in April/May. Activity peaks of each species coincided with distinct climatic conditions. Buried and partially-buried pine logs placed vertically in the soil to simulate roots and stems of seedlings were used to determine the colonisation sites of the three bark beetle species. Ninety-eight percent of O. erosus beetles were found in the protruding parts of the logs while 86% of H. ligniperda beetles were found mainly below soil level. H. angustatus were intermediate, entering the logs at or just below the soil interface but colonising mainly the buried parts in which 64% of the beetles were found. Both H. angustatus and H. ligniperda were able to detect and colonise logs buried horizontally at depths of 400mm, but O. erosus beetles were unable to do so. For adequate protection of seedlings from bark beetles, insecticide should be applied to both stems and roots. The phenology of the indigenous pine needle feeders Oosomus varius (Curculionidae) and Prasoidea sericea (Chrysomelidae) was determined by counting, at weekly intervals, the number of beetles present on 10 young pine trees. The O. varius activity peak occurred in August where 42% of all beetles were active, with 87% of the beetles present in July, August and September. P. sericea also had their activity peak in August when 60% of all beetles were active, but with August and September alone accounting for 87% of the beetles. The occurrence of the activity peaks was consistent each year over the five-year study period. This information facilitates the correct timing of prophylactic insecticide sprays.
- Full Text:
- Date Issued: 1992
Neuropharmacological interactions in the rat pineal gland a study of antidepressant drugs
- Authors: Banoo, Shabir
- Date: 1992
- Subjects: Antidepressants -- Research , Pineal gland -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3744 , http://hdl.handle.net/10962/d1003222 , Antidepressants -- Research , Pineal gland -- Research
- Description: The rat pineal gland provides a convenient model for investigating nor adrenergic receptor neurotransmission and the effects of various drugs on these processes in health and disease. The effect of a variety of antidepressant drugs on rat pineal gland function following acute and chronic administration is described. Antidepressants from several different classes increase melatonin synthesis in rat pineal gland cultures when administered acutely. This effect appears to be mediated by noradrenaline acting on postsynaptic β-adrenoceptors. Activation of these receptors, in turn, activates the enzyme serotonin N-acetyltransferase via a cyclic adenosine monophosphate (cAMP) second messenger system. Serotonin N-acetyltransferase catalyses the rate-limiting conversion of serotonin to melatonin. Blockade of postsynaptic β-adrenoceptors prevents the antidepressant-induced increase in melatonin synthesis. The possibility that atypical antidepressants as well as those that selectively inhibit serotonin reuptake may increase melatonin synthesis via a β-adrenoceptor mechanism is discussed. In contrast, however, antidepressants from different classes have variable effects on rat pineal gland function when administered repeatedly. Chronic treatment with antidepressants that selectively inhibit noradrenaline reuptake appear to down-regulate the β-adrenoceptor system while, simultaneously, increasing melatonin output. Atypical antidepressants and those that selectively inhibit serotonin reuptake appear to be without these effects when administered repeatedly. The pineal gland of normal rats may therefore not represent a suitable model for evaluating the biochemical effects of chronic antidepressant treatment. In an attempt to investigatc pineal gland function in rats with "model depression" , antidepressants were administered to chronically reserpinized rats. Treatment with reserpine produced an increase in the density of pineal β-adrenoceptors. In addition, pineal cyclic AMP accumulation and N-acetyltransferase activity were increased in reserpinized rats following exogenous catecholamine stimulation. Reserpine, by depleting intraneuronal catecholamine stores, prevented the nocturnal induction of N-acetyltransferase activity and reduced the synthesis of melatonin in pineal gland cultures. A variety of antidepressants, irrespective of their acute pharmacological actions, reversed these effects when administered chronically to resepinized rats. Acute antidepressant administration was not associated with a reversal of the reserpine-induced effects. These findings provide additional evidence against the hypothesis that antidepressant drugs act by reducing noradrenergic neurotransmission and casts doubt on the importance of β-adrenoceptor down-regulation in the mechanism of antidepressant action. The possibility that the pineal gland of the reserpinized rat may represent an alternative model for evaluating antidepressant therapies is discussed.
- Full Text:
- Date Issued: 1992
- Authors: Banoo, Shabir
- Date: 1992
- Subjects: Antidepressants -- Research , Pineal gland -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3744 , http://hdl.handle.net/10962/d1003222 , Antidepressants -- Research , Pineal gland -- Research
- Description: The rat pineal gland provides a convenient model for investigating nor adrenergic receptor neurotransmission and the effects of various drugs on these processes in health and disease. The effect of a variety of antidepressant drugs on rat pineal gland function following acute and chronic administration is described. Antidepressants from several different classes increase melatonin synthesis in rat pineal gland cultures when administered acutely. This effect appears to be mediated by noradrenaline acting on postsynaptic β-adrenoceptors. Activation of these receptors, in turn, activates the enzyme serotonin N-acetyltransferase via a cyclic adenosine monophosphate (cAMP) second messenger system. Serotonin N-acetyltransferase catalyses the rate-limiting conversion of serotonin to melatonin. Blockade of postsynaptic β-adrenoceptors prevents the antidepressant-induced increase in melatonin synthesis. The possibility that atypical antidepressants as well as those that selectively inhibit serotonin reuptake may increase melatonin synthesis via a β-adrenoceptor mechanism is discussed. In contrast, however, antidepressants from different classes have variable effects on rat pineal gland function when administered repeatedly. Chronic treatment with antidepressants that selectively inhibit noradrenaline reuptake appear to down-regulate the β-adrenoceptor system while, simultaneously, increasing melatonin output. Atypical antidepressants and those that selectively inhibit serotonin reuptake appear to be without these effects when administered repeatedly. The pineal gland of normal rats may therefore not represent a suitable model for evaluating the biochemical effects of chronic antidepressant treatment. In an attempt to investigatc pineal gland function in rats with "model depression" , antidepressants were administered to chronically reserpinized rats. Treatment with reserpine produced an increase in the density of pineal β-adrenoceptors. In addition, pineal cyclic AMP accumulation and N-acetyltransferase activity were increased in reserpinized rats following exogenous catecholamine stimulation. Reserpine, by depleting intraneuronal catecholamine stores, prevented the nocturnal induction of N-acetyltransferase activity and reduced the synthesis of melatonin in pineal gland cultures. A variety of antidepressants, irrespective of their acute pharmacological actions, reversed these effects when administered chronically to resepinized rats. Acute antidepressant administration was not associated with a reversal of the reserpine-induced effects. These findings provide additional evidence against the hypothesis that antidepressant drugs act by reducing noradrenergic neurotransmission and casts doubt on the importance of β-adrenoceptor down-regulation in the mechanism of antidepressant action. The possibility that the pineal gland of the reserpinized rat may represent an alternative model for evaluating antidepressant therapies is discussed.
- Full Text:
- Date Issued: 1992
Up Beat Issue Number 10 1992
- SACHED
- Authors: SACHED
- Date: 1992
- Subjects: SACHED
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/116706 , vital:34427
- Description: The days are getting longer and warmer. It is almost holiday time. This year, there is no need to sit around feeling bored. There are lots of exciting events for young people in the December holidays. Many youth feel that places like museums and art galleries, aren't for them. But they are for everyone. Learn to paint t-shirts or to do beadwork. Attend a workshop on photography or spend an afternoon learning to be a DJ - mixing and scratching records. Find out about all these exciting holiday events on page 36. Upbeat has also organised Upbeat Days. We've got together with schools and resource centres around the country. There will be clean-ups and plays, beach walks and treasure hunts, food, fun and great prizes to win. Why not write a story for Upbeat during the holidays? Spend a day being a reporter. If we publish your story, you will be R30 richer. Find out how to be an Upbeat reporter on page 7. Here's another holiday idea! Put your feet up and spend the afternoon enjoying reading this issue of Upbeat. Read about Bronwyn, the young local teenage star. Wangari Maathai is a tireless and brave woman from Kenya. Don't miss her story on page 4. Have fun making a mask. Or try and find your way through our mind-boggling maze. Reading and learning is always fun with Upbeat!
- Full Text:
- Date Issued: 1992
- Authors: SACHED
- Date: 1992
- Subjects: SACHED
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/116706 , vital:34427
- Description: The days are getting longer and warmer. It is almost holiday time. This year, there is no need to sit around feeling bored. There are lots of exciting events for young people in the December holidays. Many youth feel that places like museums and art galleries, aren't for them. But they are for everyone. Learn to paint t-shirts or to do beadwork. Attend a workshop on photography or spend an afternoon learning to be a DJ - mixing and scratching records. Find out about all these exciting holiday events on page 36. Upbeat has also organised Upbeat Days. We've got together with schools and resource centres around the country. There will be clean-ups and plays, beach walks and treasure hunts, food, fun and great prizes to win. Why not write a story for Upbeat during the holidays? Spend a day being a reporter. If we publish your story, you will be R30 richer. Find out how to be an Upbeat reporter on page 7. Here's another holiday idea! Put your feet up and spend the afternoon enjoying reading this issue of Upbeat. Read about Bronwyn, the young local teenage star. Wangari Maathai is a tireless and brave woman from Kenya. Don't miss her story on page 4. Have fun making a mask. Or try and find your way through our mind-boggling maze. Reading and learning is always fun with Upbeat!
- Full Text:
- Date Issued: 1992
Evaluation of three simple hydrosalinity models applied to citrus orchards in the Lower Coerney River irrigation area, Eastern Cape, South Africa
- Authors: Cobban, Dale Anne
- Date: 1992
- Subjects: Irrigation -- Management , Irrigation -- Research -- South Africa -- Eastern Cape , Water in agriculture , Citrus -- Irrigation -- South Africa , Soils, Salts in
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4829 , http://hdl.handle.net/10962/d1005504 , Irrigation -- Management , Irrigation -- Research -- South Africa -- Eastern Cape , Water in agriculture , Citrus -- Irrigation -- South Africa , Soils, Salts in
- Description: Three hydrosalinity models of different complexity were evaluated against data from selected citrus orchards in the Lower Coerney River irrigation area. These models were statistically compared with field data, and found to vary in accuracy of output predictions. The simplest model, the LEACHING REQUIREMENT (LR) model, has the lowest data input requirements and produces output predictions that correlate with up to 93% of the variance in measured data. SODICS, which is theoretically more detailed and requires a greater level of detail in input, produces predictions of an accuracy equivalent to the LR model. The PEAK model was assessed in two parts, the PEAKM module simulating soil moisture and soil moisture movement was able to predict variations in moisture up to 99% of the time. The PEAKD module, which predicts solute concentrations was less effective in replicating real world conditions
- Full Text:
- Date Issued: 1992
- Authors: Cobban, Dale Anne
- Date: 1992
- Subjects: Irrigation -- Management , Irrigation -- Research -- South Africa -- Eastern Cape , Water in agriculture , Citrus -- Irrigation -- South Africa , Soils, Salts in
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4829 , http://hdl.handle.net/10962/d1005504 , Irrigation -- Management , Irrigation -- Research -- South Africa -- Eastern Cape , Water in agriculture , Citrus -- Irrigation -- South Africa , Soils, Salts in
- Description: Three hydrosalinity models of different complexity were evaluated against data from selected citrus orchards in the Lower Coerney River irrigation area. These models were statistically compared with field data, and found to vary in accuracy of output predictions. The simplest model, the LEACHING REQUIREMENT (LR) model, has the lowest data input requirements and produces output predictions that correlate with up to 93% of the variance in measured data. SODICS, which is theoretically more detailed and requires a greater level of detail in input, produces predictions of an accuracy equivalent to the LR model. The PEAK model was assessed in two parts, the PEAKM module simulating soil moisture and soil moisture movement was able to predict variations in moisture up to 99% of the time. The PEAKD module, which predicts solute concentrations was less effective in replicating real world conditions
- Full Text:
- Date Issued: 1992
Mchuyo
- Venancio Mbande and his Chopi timbila xylophone group, Tracey, Andrew T N
- Authors: Venancio Mbande and his Chopi timbila xylophone group , Tracey, Andrew T N
- Date: 1992
- Subjects: Chopi (African people) -- South Africa , Folk music , Xylophone music , Rattle (Musical instrument) , Drum (Musical instrument) , Africa South Africa Rustenburg f-sa
- Language: Chopi
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/96466 , vital:31281 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC049b-01
- Description: Traditional dance song accompanied by timbila xylophone rattles and one drum
- Full Text: false
- Date Issued: 1992
- Authors: Venancio Mbande and his Chopi timbila xylophone group , Tracey, Andrew T N
- Date: 1992
- Subjects: Chopi (African people) -- South Africa , Folk music , Xylophone music , Rattle (Musical instrument) , Drum (Musical instrument) , Africa South Africa Rustenburg f-sa
- Language: Chopi
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/96466 , vital:31281 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC049b-01
- Description: Traditional dance song accompanied by timbila xylophone rattles and one drum
- Full Text: false
- Date Issued: 1992
A study of Ngugi wa Thiong'o's later novels to assess his adaptation of dramatic techniques and Gikuyu oral traditions to the requirements of fiction
- Authors: Erapu, Laban Omella
- Date: 1992
- Subjects: Ngũgĩ wa Thiongʼo, 1938- Folk literature, Kikuyu Oral tradition -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2235 , http://hdl.handle.net/10962/d1002278
- Description: This thesis examines Ngugi wa Thiong'o's later writings in order to establish the nature of his quest for a people's literature. It illustrates how the author attempts to break the barriers between traditional oral forms and the relatively new written forms in addressing a basically "illiterate" audience. The research begins with an exploration of Gikuyu oral literature as an essential background to Ngugi's later dramatic and fictional writings as distinct from his earlier literary works in which he initiates the dominant quest for a more just society. Ngugi's return to these roots constitutes the central "homecoming" that characterizes his search for new forms. The analysis is conducted through three significant chronological stages representing Ngugi's writings over a period of about a decade from the mid-1970s to the early 1980s. Each stage starts with a play and performance followed by a parallel novel, the first pair written in English and the subsequent ones in Gikuyu. The three stages - designated Transition, Homecoming and Realization - mark Ngugi's involvement in the promotion of Gikuyu culture and orature, both as a source of inspiration and as a cause to which he fully dedicates himself. The transitional stage depicts the convergence between conventional and traditional oral literary forms with which Ngugi begins to experiment. The second stage introduces significant departures as Ngugi begins to use the Gikuyu language as his primary medium of creative expression. The final stage demonstrates his ultimate assertion of the primacy of orality over the written word as a dynamic agent of transmission. The thesis concludes that Ngugi wa Thiong'o in these later works - while leaving the possibilities of his vision of a "New Earth" unfulfilled pioneers the African writers' climb down from an "ivory tower" to deal with the realities of the experience of the predominantly non-reading African masses, acknowledged as both recipients of and active participants in the relatively new written literature which purports to speak for their experiences and their times.
- Full Text:
- Date Issued: 1992
- Authors: Erapu, Laban Omella
- Date: 1992
- Subjects: Ngũgĩ wa Thiongʼo, 1938- Folk literature, Kikuyu Oral tradition -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2235 , http://hdl.handle.net/10962/d1002278
- Description: This thesis examines Ngugi wa Thiong'o's later writings in order to establish the nature of his quest for a people's literature. It illustrates how the author attempts to break the barriers between traditional oral forms and the relatively new written forms in addressing a basically "illiterate" audience. The research begins with an exploration of Gikuyu oral literature as an essential background to Ngugi's later dramatic and fictional writings as distinct from his earlier literary works in which he initiates the dominant quest for a more just society. Ngugi's return to these roots constitutes the central "homecoming" that characterizes his search for new forms. The analysis is conducted through three significant chronological stages representing Ngugi's writings over a period of about a decade from the mid-1970s to the early 1980s. Each stage starts with a play and performance followed by a parallel novel, the first pair written in English and the subsequent ones in Gikuyu. The three stages - designated Transition, Homecoming and Realization - mark Ngugi's involvement in the promotion of Gikuyu culture and orature, both as a source of inspiration and as a cause to which he fully dedicates himself. The transitional stage depicts the convergence between conventional and traditional oral literary forms with which Ngugi begins to experiment. The second stage introduces significant departures as Ngugi begins to use the Gikuyu language as his primary medium of creative expression. The final stage demonstrates his ultimate assertion of the primacy of orality over the written word as a dynamic agent of transmission. The thesis concludes that Ngugi wa Thiong'o in these later works - while leaving the possibilities of his vision of a "New Earth" unfulfilled pioneers the African writers' climb down from an "ivory tower" to deal with the realities of the experience of the predominantly non-reading African masses, acknowledged as both recipients of and active participants in the relatively new written literature which purports to speak for their experiences and their times.
- Full Text:
- Date Issued: 1992
The tonology of Xhosa
- Authors: Claughton, John Sellick
- Date: 1992
- Subjects: Xhosa language -- Tone
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3596 , http://hdl.handle.net/10962/d1002171
- Description: This thesis is an examination of the tonology of Xhosa. After an initial survey of the surface tones of the language, and a review of previous studies of Xhosa tone, a description is given of the major tonal patterns of Xhosa noun and verb morphology. In the course of this description the major tonologica1 rules are allowed to emerge. In particular it is shown that some of these rules lead to complex patterns of variation in the pronunciation of the same individual. The derivation of the tone patterns of adjectives and relatives is discussed and it is shown that these tone patterns offer partial support for the derivation of some adjective and relative constructions as derived from embedded sentences but also support for deriving simple attributive adjective constructions by means of phrase structure rules. Some interesting tonal patterns such as that shown by reduplicated stems are then explored. The tones of loan words are then investigated and evidence for the identification of English and Afrikaans stress with high tones by Xhosa speakers is adduced. In the final chapter certain general problems of Xhosa tone are discussed. In particular it is argued that attempts to interpret the tonal system in terms of an accent are unrevealing and also it is suggested that attempts to unify the various rules that spread tones to the right are mistaken. In the appendices a comprehensive survey of the tones of Xhosa inflections is given together with a substantial list of Xhosa words with the tones marked.
- Full Text:
- Date Issued: 1992
- Authors: Claughton, John Sellick
- Date: 1992
- Subjects: Xhosa language -- Tone
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3596 , http://hdl.handle.net/10962/d1002171
- Description: This thesis is an examination of the tonology of Xhosa. After an initial survey of the surface tones of the language, and a review of previous studies of Xhosa tone, a description is given of the major tonal patterns of Xhosa noun and verb morphology. In the course of this description the major tonologica1 rules are allowed to emerge. In particular it is shown that some of these rules lead to complex patterns of variation in the pronunciation of the same individual. The derivation of the tone patterns of adjectives and relatives is discussed and it is shown that these tone patterns offer partial support for the derivation of some adjective and relative constructions as derived from embedded sentences but also support for deriving simple attributive adjective constructions by means of phrase structure rules. Some interesting tonal patterns such as that shown by reduplicated stems are then explored. The tones of loan words are then investigated and evidence for the identification of English and Afrikaans stress with high tones by Xhosa speakers is adduced. In the final chapter certain general problems of Xhosa tone are discussed. In particular it is argued that attempts to interpret the tonal system in terms of an accent are unrevealing and also it is suggested that attempts to unify the various rules that spread tones to the right are mistaken. In the appendices a comprehensive survey of the tones of Xhosa inflections is given together with a substantial list of Xhosa words with the tones marked.
- Full Text:
- Date Issued: 1992
Environmentalism and its implications for education: a study of private schools in the Eastern Cape
- Authors: Slade, Wilfred John
- Date: 1992
- Subjects: Environmental education -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa Private schools -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1520 , http://hdl.handle.net/10962/d1003402
- Description: This study explores the extent to which the ethos and the basic approach to education taken by three Eastern Cape private schools influences the practice of environmental education within these schools. Their environmental education programmes are evaluated in terms of the guiding principles adopted by the international community in the 'Tbilisi Principles of Environmental Education'. An ethnographic approach was adopted for this research and findings are essentially descriptive and qualitative, with special regard to social structures and the attitudes of individuals within these structures.
- Full Text:
- Date Issued: 1992
- Authors: Slade, Wilfred John
- Date: 1992
- Subjects: Environmental education -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa Private schools -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1520 , http://hdl.handle.net/10962/d1003402
- Description: This study explores the extent to which the ethos and the basic approach to education taken by three Eastern Cape private schools influences the practice of environmental education within these schools. Their environmental education programmes are evaluated in terms of the guiding principles adopted by the international community in the 'Tbilisi Principles of Environmental Education'. An ethnographic approach was adopted for this research and findings are essentially descriptive and qualitative, with special regard to social structures and the attitudes of individuals within these structures.
- Full Text:
- Date Issued: 1992