The spatial planning of racial residential segregation in King William's Town : 1826-1991
- Authors: Zituta, Heyman Mandlakayise
- Date: 1997
- Subjects: Apartheid -- South Africa -- King William's Town , City planning -- South Africa -- King William's Town , King William's Town (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4855 , http://hdl.handle.net/10962/d1005531 , Apartheid -- South Africa -- King William's Town , City planning -- South Africa -- King William's Town , King William's Town (South Africa) -- History
- Description: This study investigates the spatial planning of racial residential segregation in King William's Town, induding its former homeland township of Zwelitsha, from 1826 to 1991. The first settlement in the 'white' King William's Town, Brownlee Mission Station, was established in 1826.The town of King William's Town was developed from this settlement. The racial laws which were applied to segregate blacks nationally and locally came to an end in 1991. Primary sources of information were used to determine whether King William's Town was planned along racial lines and to determine the major role players who formulated and implemented the policy. Key sources were archival material, newspapers, maps, interviews, Deeds Office files and the work of other scholars. The establishment of the towm from its genesis as a mission station and a military base is traced and the effects of this legacy on racial separation is detailed. It was found that racial planning of residential areas in King William's Town had been practised in this small town for a long time (prior to the Group Areas Act). The implementation of this policy was marked by forced removal of blacks from areas which were regarded as being for whites. These predominently African concentrations on the east bank of the Buffalo River were relocated to the west bank which was regarded as a black area.An anomalous incident was discovered in this study namely that these racial removals took place before the central state introduced national policy which compelled all local states to plan their residential areas along ethnic considerations. In parallel with the practice of segregation in King William's Town, the township of Zwelitsha was developed adjacent to the town by the government. As this thesis reveals, the development of Zwelitsha was intimately related to that of King William's Town. The major role players in planning residential areas on racial basis were identified as the municipal Council of King William's Town. They were involved in planning racially segregated areas before and after the Group Areas Act. They (the Council) succeeded in closing all freehold locations in the town (1940) and forced the residents to become their tenants who rented dwellings in the west bank municipal location. There were attempts to incorporate this municipal location into the neighbouring homeland township of Zwelitsha. This move was eventually accomplished when all townships in the vicinity of King William's Town were amalgamated to form King William's Town Transitional Local Council in terms of the Local Government Transition Act of 1994 (Government Gazette No. 15468 of 2nd February 1994).
- Full Text:
- Date Issued: 1997
- Authors: Zituta, Heyman Mandlakayise
- Date: 1997
- Subjects: Apartheid -- South Africa -- King William's Town , City planning -- South Africa -- King William's Town , King William's Town (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4855 , http://hdl.handle.net/10962/d1005531 , Apartheid -- South Africa -- King William's Town , City planning -- South Africa -- King William's Town , King William's Town (South Africa) -- History
- Description: This study investigates the spatial planning of racial residential segregation in King William's Town, induding its former homeland township of Zwelitsha, from 1826 to 1991. The first settlement in the 'white' King William's Town, Brownlee Mission Station, was established in 1826.The town of King William's Town was developed from this settlement. The racial laws which were applied to segregate blacks nationally and locally came to an end in 1991. Primary sources of information were used to determine whether King William's Town was planned along racial lines and to determine the major role players who formulated and implemented the policy. Key sources were archival material, newspapers, maps, interviews, Deeds Office files and the work of other scholars. The establishment of the towm from its genesis as a mission station and a military base is traced and the effects of this legacy on racial separation is detailed. It was found that racial planning of residential areas in King William's Town had been practised in this small town for a long time (prior to the Group Areas Act). The implementation of this policy was marked by forced removal of blacks from areas which were regarded as being for whites. These predominently African concentrations on the east bank of the Buffalo River were relocated to the west bank which was regarded as a black area.An anomalous incident was discovered in this study namely that these racial removals took place before the central state introduced national policy which compelled all local states to plan their residential areas along ethnic considerations. In parallel with the practice of segregation in King William's Town, the township of Zwelitsha was developed adjacent to the town by the government. As this thesis reveals, the development of Zwelitsha was intimately related to that of King William's Town. The major role players in planning residential areas on racial basis were identified as the municipal Council of King William's Town. They were involved in planning racially segregated areas before and after the Group Areas Act. They (the Council) succeeded in closing all freehold locations in the town (1940) and forced the residents to become their tenants who rented dwellings in the west bank municipal location. There were attempts to incorporate this municipal location into the neighbouring homeland township of Zwelitsha. This move was eventually accomplished when all townships in the vicinity of King William's Town were amalgamated to form King William's Town Transitional Local Council in terms of the Local Government Transition Act of 1994 (Government Gazette No. 15468 of 2nd February 1994).
- Full Text:
- Date Issued: 1997
A predictive biogeography of selected alien plant invaders in South Africa
- Authors: Youthed, Jennifer Gay
- Date: 1997
- Subjects: Alien plants -- South Africa , Biogeography -- South Africa , Acacia -- South Africa , Acacia mearnsii -- South Africa , Opuntia ficus-indica -- South Africa , Solanum -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4846 , http://hdl.handle.net/10962/d1005522 , Alien plants -- South Africa , Biogeography -- South Africa , Acacia -- South Africa , Acacia mearnsii -- South Africa , Opuntia ficus-indica -- South Africa , Solanum -- South Africa
- Description: Five techniques were used to predict the potential biogeography of the four alien plant species, Acacia longifolia, Acacia mearnsii, Opuntia ficus-indica and Solanum sisymbrifolium. Prediction was based on five environmental factors, median annual rainfall, co-efficient of variation for rainfall, mean monthly maximum temperature for January, mean monthly minimum temperature for July and elevation. A geographical information system was used to manage the data and produce the predictive maps. The models were constructed with presence and absence data and then validated by means of an independent data set and chisquared tests. Of the five models used, three (the range, principal components analysis and discriminant function analysis) were linear while the other two (artificial neural networks and fuzzy logic) were non-linear. The two non-linear techniques were chosen as a plant's response to its environment is commonly assumed to be non-linear. However, these two techniques did not offer significant advantages over the linear methods. The principal components analysis was particularly useful in ascertaining the variables that were important in determining the distribution of each species. Artifacts on the predictive maps were also proved useful for this purpose. The techniques that produced the most statistically accurate validation results were the artificial neural networks (77% correct median prediction rate) and the discriminant function analysis (71% correct median prediction rate) while the techniques that performed the worst were the range and the fuzzy classification. The artificial neural network, discriminant function analysis and principal component analysis techniques all show great potential as predictive distribution models.
- Full Text:
- Date Issued: 1997
- Authors: Youthed, Jennifer Gay
- Date: 1997
- Subjects: Alien plants -- South Africa , Biogeography -- South Africa , Acacia -- South Africa , Acacia mearnsii -- South Africa , Opuntia ficus-indica -- South Africa , Solanum -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4846 , http://hdl.handle.net/10962/d1005522 , Alien plants -- South Africa , Biogeography -- South Africa , Acacia -- South Africa , Acacia mearnsii -- South Africa , Opuntia ficus-indica -- South Africa , Solanum -- South Africa
- Description: Five techniques were used to predict the potential biogeography of the four alien plant species, Acacia longifolia, Acacia mearnsii, Opuntia ficus-indica and Solanum sisymbrifolium. Prediction was based on five environmental factors, median annual rainfall, co-efficient of variation for rainfall, mean monthly maximum temperature for January, mean monthly minimum temperature for July and elevation. A geographical information system was used to manage the data and produce the predictive maps. The models were constructed with presence and absence data and then validated by means of an independent data set and chisquared tests. Of the five models used, three (the range, principal components analysis and discriminant function analysis) were linear while the other two (artificial neural networks and fuzzy logic) were non-linear. The two non-linear techniques were chosen as a plant's response to its environment is commonly assumed to be non-linear. However, these two techniques did not offer significant advantages over the linear methods. The principal components analysis was particularly useful in ascertaining the variables that were important in determining the distribution of each species. Artifacts on the predictive maps were also proved useful for this purpose. The techniques that produced the most statistically accurate validation results were the artificial neural networks (77% correct median prediction rate) and the discriminant function analysis (71% correct median prediction rate) while the techniques that performed the worst were the range and the fuzzy classification. The artificial neural network, discriminant function analysis and principal component analysis techniques all show great potential as predictive distribution models.
- Full Text:
- Date Issued: 1997
Radio observation of the Gum Nebula Region
- Authors: Woermann, Beate
- Date: 1997
- Subjects: Radio sources (Astronomy) Nebulae -- Observations Radio astronomy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5485 , http://hdl.handle.net/10962/d1005271
- Description: This thesis describes the results of an investigation of the physical properties of the Gum Nebula. For this investigation a radio continuum map of the region was made at 2326 MHz and resolution ⅓° with the HartRAO antenna. This map was used to generate spectral index images and an infrared to radio flux density ratio (IRR) image. The latter image shows that the IRR of the nebula is in the range 20 to 250, identifying it as an old SNR. Several spectral index images of this region were generated using two different methods, one based on the isolation of the nebula from its background radiation, the other based on TT-plots (Turtle et al., 1962). The two methods yield similar results, which show that the nebula has a thermal shell with a non-thermal region in its interior. Below the galactic plane the thermal region dominates and above the plane the nonthermal region. These results suggest a model of an old SNR with an H II region shell. Spectral line observations of hydrogen recombination lines and hydroxyl (OH) were made with the HartRAO and the Mopra telescopes. The detection of hydrogen recombination lines at four positions in the thermal regions of the nebula give electron temperatures and emission measures in the ranges 4000 to 6000 K and 220 to 460 pc.cm⁻⁶ respectively. The turbulent velocities are of the order of 20 km/s. A search for shocked OH lines at 1667 MHz and 1720 MHz in the Gum Nebula gave results that were negative, but numerous unshocked 1667 MHz OH lines were detected. The latter were used in a test for an expansion of the nebula. The most plausible fit to the data gives an expansion centre at l = 260.5°, b = -2.5° and at a distance of 0.7 kpc from us. The front face angular radius and expansion velocity are 10.5° and 16 km/s respectively. The back face angular radius and expansion velocity are 8.50 and 7 km/s respectively.
- Full Text:
- Date Issued: 1997
- Authors: Woermann, Beate
- Date: 1997
- Subjects: Radio sources (Astronomy) Nebulae -- Observations Radio astronomy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5485 , http://hdl.handle.net/10962/d1005271
- Description: This thesis describes the results of an investigation of the physical properties of the Gum Nebula. For this investigation a radio continuum map of the region was made at 2326 MHz and resolution ⅓° with the HartRAO antenna. This map was used to generate spectral index images and an infrared to radio flux density ratio (IRR) image. The latter image shows that the IRR of the nebula is in the range 20 to 250, identifying it as an old SNR. Several spectral index images of this region were generated using two different methods, one based on the isolation of the nebula from its background radiation, the other based on TT-plots (Turtle et al., 1962). The two methods yield similar results, which show that the nebula has a thermal shell with a non-thermal region in its interior. Below the galactic plane the thermal region dominates and above the plane the nonthermal region. These results suggest a model of an old SNR with an H II region shell. Spectral line observations of hydrogen recombination lines and hydroxyl (OH) were made with the HartRAO and the Mopra telescopes. The detection of hydrogen recombination lines at four positions in the thermal regions of the nebula give electron temperatures and emission measures in the ranges 4000 to 6000 K and 220 to 460 pc.cm⁻⁶ respectively. The turbulent velocities are of the order of 20 km/s. A search for shocked OH lines at 1667 MHz and 1720 MHz in the Gum Nebula gave results that were negative, but numerous unshocked 1667 MHz OH lines were detected. The latter were used in a test for an expansion of the nebula. The most plausible fit to the data gives an expansion centre at l = 260.5°, b = -2.5° and at a distance of 0.7 kpc from us. The front face angular radius and expansion velocity are 10.5° and 16 km/s respectively. The back face angular radius and expansion velocity are 8.50 and 7 km/s respectively.
- Full Text:
- Date Issued: 1997
A revised checklist of the epipelagic and shore fishes of the Chagos Archipelago, central Indian Ocean
- Winterbottom, Richard, 1944-, Anderson, R Charles
- Authors: Winterbottom, Richard, 1944- , Anderson, R Charles
- Date: 1997
- Language: English
- Type: Text
- Identifier: vital:15031 , http://hdl.handle.net/10962/d1019907 , ISSN 0073-4381 , Ichthyological Bulletin J.L.B. Smith Institute of Ichthyology; No. 66
- Description: A recent (Feb.-Mar., 1996) trip to the Chagos Archipelago, central Indian Ocean, by one of us (RCA) resulted in 51 new records of fishes for the islands. In addition, another 29 new records were discovered either in the collections of the National Museum of Natural History at the Smithsonian Institution, or were gleaned from the literature. In total, 80 new records for Chagos are reported here. The checklist by Winterbottom et al. (1989) recorded 703 species from Chagos, that total is raised to 773 species. Eighty-nine changes in nomenclature from that used in the 1989 list are documented. Three geographic localities (Indo-Pacific, Indo-west Pacific and marginally on the Pacific plate, and Indo-west Pacific) account for just over 80% of the fish fauna. The five most speciose families (numbers of species in parentheses) are the Gobiidae (98), Labridae (63), Serranidae (50), Muraenidae (41) and Pomacentridae (38), and these together account for 38% of the total fish fauna. , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1997
- Authors: Winterbottom, Richard, 1944- , Anderson, R Charles
- Date: 1997
- Language: English
- Type: Text
- Identifier: vital:15031 , http://hdl.handle.net/10962/d1019907 , ISSN 0073-4381 , Ichthyological Bulletin J.L.B. Smith Institute of Ichthyology; No. 66
- Description: A recent (Feb.-Mar., 1996) trip to the Chagos Archipelago, central Indian Ocean, by one of us (RCA) resulted in 51 new records of fishes for the islands. In addition, another 29 new records were discovered either in the collections of the National Museum of Natural History at the Smithsonian Institution, or were gleaned from the literature. In total, 80 new records for Chagos are reported here. The checklist by Winterbottom et al. (1989) recorded 703 species from Chagos, that total is raised to 773 species. Eighty-nine changes in nomenclature from that used in the 1989 list are documented. Three geographic localities (Indo-Pacific, Indo-west Pacific and marginally on the Pacific plate, and Indo-west Pacific) account for just over 80% of the fish fauna. The five most speciose families (numbers of species in parentheses) are the Gobiidae (98), Labridae (63), Serranidae (50), Muraenidae (41) and Pomacentridae (38), and these together account for 38% of the total fish fauna. , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1997
Macroinvertebrate community and species responses to chlorinated sewage effluent in the Umsunduze and Umbilo rivers, Kwa Zulu-Natal, South Africa
- Authors: Williams, Margot Lluttrell
- Date: 1997
- Subjects: Sewage -- Environmental aspects -- South Africa -- KwaZulu-Natal , Sewage -- Purification -- Chlorination -- South Africa -- KwaZulu-Natal , Baetis -- South Africa -- KwaZulu-Natal , Mayflies -- South Africa -- KwaZulu-Natal , Chlorine -- Environmental aspects -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5727 , http://hdl.handle.net/10962/d1005413 , Sewage -- Environmental aspects -- South Africa -- KwaZulu-Natal , Sewage -- Purification -- Chlorination -- South Africa -- KwaZulu-Natal , Baetis -- South Africa -- KwaZulu-Natal , Mayflies -- South Africa -- KwaZulu-Natal , Chlorine -- Environmental aspects -- South Africa -- KwaZulu-Natal
- Description: Chlorine has a wide variety of applications in water treatment. Because of its disinfectant efficacy, it is used world wide for the treatment of potable water, sewage, swimming pools and for the control of nuisance organisms in cooling towers. A problem arises when such chlorinated water enters the natural environment, as chlorine's greatest advantage, i.e. its germicidal capacity, becomes its greatest disadvantage. In particular, the discharge of heated, chlorinated water from cooling towers and chlorinated, treated sewage into rivers have severe consequences for the riverine flora and fauna. This study focused on the effects of chlorinated, treated sewage effluent on the community structure of benthic macroinvertebrates in two rivers in KwaZulu-Natal viz. the Umsunduze River in the Pietermaritzburg area, and the Umbilo River in the Durban area. The study was conducted in three phases. The first two phases comprised a toxicological investigation of the effects of chlorine on a selected riverine macroinvertebrate, and the third phase comprised an ecotoxicological investigation of the effects of chlorinated treated sewage on benthic macroinvertebrate community structure. The first phase of the study involved the development of an artificial stream system which would be suitable for determining the response of a selected macroinvertebrate species to chlorine. Chlorine is both reactive and volatile, so this necessitated the development of a specialised flow-through system with apparatus which would allow continuous dosing of a sodium hypochlorite solution. The system was set up at the Process Evaluation Facility at Wiggins Waterworks, Durban, where raw water from lnanda Dam was used. The second phase involved the use of this artificial stream system to conduct acute 96 h toxicity tests. Baetid mayfly nymphs (Baetis harrisoni Barnard) were selected as the test organisms after a preliminary investigation found them to be suitable for survival under laboratory conditions. For comparative purposes, tests were run first on B. harrisoni from a relatively uncontaminated stream in a residential area of Westville, then on specimens from the severely impacted Umbilo River. The LC₅₀ of chlorine for organisms from both sources was found to be in the region of 0.004 mg/l (free chlorine). This value was well below the general effluent standard of 0.1 mg/l in effect at the time. The recommended acute environmental guideline is 0.001 mg/l. The third phase of the study involved field validation of the toxicity test results. It was hypothesised that since the LC₅₀ for free chlorine was 0.004 mg/l, B. harrisoni would not be found downstream from a point source of chlorinated effluent where the concentration of free chlorine ranged from 0.06 to 0.2 mg/l, and that the macroinvertebrate community structure would also be altered. In order to test these hypotheses, benthic macro invertebrate community structure was investigated at several sites up- and downstream from the outlets of the Darvill Wastewater Works in the Umsunduze River and the Umbilo Sewage Purification Works in the Umbilo River. In addition, in order to differentiate between the effects of chlorinated and unchlorinated treated sewage, a section of the Umbilo River (upstream from the chlorinated discharge) was exposed to unchlorinated, treated sewage. In this way, a limited "before and after" sewage and an "upstream and downstream" from sewage investigation could be carried out. Organisms were collected from riffles (and from pools in the Umbilo River) and the samples were then sorted and organisms were identified to species level, where possible, otherwise to genus or family. Changes in community composition were shown graphically as pie charts of relative proportions of organisms found at each site, graphs of the average number of taxa at each site; and graphs of the average number of individuals at each site; Data from the Umbilo River were also analysed using TWINSPAN (Two-way indicator species analysis). In both the Umsunduze and the Umbilo rivers, the deleterious effects of the chlorinated effluent were clearly evident. At Umsunduze Site 3 and Umbilo Site 5 (both immediately downstream from the chlorinated effluent) both the number of taxa and number of individuals were substantially reduced, sometimes to zero. Where organisms were found at the next sites downstream (Sites 4 and 6 respectively), the samples were dominated by Chironomus. In contrast, the unchlorinated effluent in the Umbilo River caused very little difference in community structure. As predicted, B. harrisoni was not found in downstream samples in which chlorine was present, yet appeared to be relatively unaffected by the unchlorinated effluent, suggesting that chlorine, rather than the effluent was responsible for its absence at downstream sites. In conclusion, it would appear that while treated sewage effluent certainly causes changes in macroinvertebrate community structure, chlorination of this effluent leads to large scale destruction of the riverine community. This in turn delays the recovery process of the river, rendering a longer stretch unfit for use. The consequences of this delayed recovery are that the failure to meet the water quality requirements of the natural environment results in those of the other water users (agriculture, industry, domestic and recreation) not being met. This reduces the natural capacity of the riverine community to process organic waste and recover from the discharge of sewage effluent. Chlorination increases the distance of impaired water quality and environmental integrity which result from organically enriched treated sewage effluent. The results of the study indicated that the draft water quality guidelines for aquatic ecosystems, derived from inadequate data, and calculated with a safety factor, were the correct order of magnitude. The approach followed in the study will be useful in the development and refinement of water quality guidelines for aquatic ecosystems.
- Full Text:
- Date Issued: 1997
- Authors: Williams, Margot Lluttrell
- Date: 1997
- Subjects: Sewage -- Environmental aspects -- South Africa -- KwaZulu-Natal , Sewage -- Purification -- Chlorination -- South Africa -- KwaZulu-Natal , Baetis -- South Africa -- KwaZulu-Natal , Mayflies -- South Africa -- KwaZulu-Natal , Chlorine -- Environmental aspects -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5727 , http://hdl.handle.net/10962/d1005413 , Sewage -- Environmental aspects -- South Africa -- KwaZulu-Natal , Sewage -- Purification -- Chlorination -- South Africa -- KwaZulu-Natal , Baetis -- South Africa -- KwaZulu-Natal , Mayflies -- South Africa -- KwaZulu-Natal , Chlorine -- Environmental aspects -- South Africa -- KwaZulu-Natal
- Description: Chlorine has a wide variety of applications in water treatment. Because of its disinfectant efficacy, it is used world wide for the treatment of potable water, sewage, swimming pools and for the control of nuisance organisms in cooling towers. A problem arises when such chlorinated water enters the natural environment, as chlorine's greatest advantage, i.e. its germicidal capacity, becomes its greatest disadvantage. In particular, the discharge of heated, chlorinated water from cooling towers and chlorinated, treated sewage into rivers have severe consequences for the riverine flora and fauna. This study focused on the effects of chlorinated, treated sewage effluent on the community structure of benthic macroinvertebrates in two rivers in KwaZulu-Natal viz. the Umsunduze River in the Pietermaritzburg area, and the Umbilo River in the Durban area. The study was conducted in three phases. The first two phases comprised a toxicological investigation of the effects of chlorine on a selected riverine macroinvertebrate, and the third phase comprised an ecotoxicological investigation of the effects of chlorinated treated sewage on benthic macroinvertebrate community structure. The first phase of the study involved the development of an artificial stream system which would be suitable for determining the response of a selected macroinvertebrate species to chlorine. Chlorine is both reactive and volatile, so this necessitated the development of a specialised flow-through system with apparatus which would allow continuous dosing of a sodium hypochlorite solution. The system was set up at the Process Evaluation Facility at Wiggins Waterworks, Durban, where raw water from lnanda Dam was used. The second phase involved the use of this artificial stream system to conduct acute 96 h toxicity tests. Baetid mayfly nymphs (Baetis harrisoni Barnard) were selected as the test organisms after a preliminary investigation found them to be suitable for survival under laboratory conditions. For comparative purposes, tests were run first on B. harrisoni from a relatively uncontaminated stream in a residential area of Westville, then on specimens from the severely impacted Umbilo River. The LC₅₀ of chlorine for organisms from both sources was found to be in the region of 0.004 mg/l (free chlorine). This value was well below the general effluent standard of 0.1 mg/l in effect at the time. The recommended acute environmental guideline is 0.001 mg/l. The third phase of the study involved field validation of the toxicity test results. It was hypothesised that since the LC₅₀ for free chlorine was 0.004 mg/l, B. harrisoni would not be found downstream from a point source of chlorinated effluent where the concentration of free chlorine ranged from 0.06 to 0.2 mg/l, and that the macroinvertebrate community structure would also be altered. In order to test these hypotheses, benthic macro invertebrate community structure was investigated at several sites up- and downstream from the outlets of the Darvill Wastewater Works in the Umsunduze River and the Umbilo Sewage Purification Works in the Umbilo River. In addition, in order to differentiate between the effects of chlorinated and unchlorinated treated sewage, a section of the Umbilo River (upstream from the chlorinated discharge) was exposed to unchlorinated, treated sewage. In this way, a limited "before and after" sewage and an "upstream and downstream" from sewage investigation could be carried out. Organisms were collected from riffles (and from pools in the Umbilo River) and the samples were then sorted and organisms were identified to species level, where possible, otherwise to genus or family. Changes in community composition were shown graphically as pie charts of relative proportions of organisms found at each site, graphs of the average number of taxa at each site; and graphs of the average number of individuals at each site; Data from the Umbilo River were also analysed using TWINSPAN (Two-way indicator species analysis). In both the Umsunduze and the Umbilo rivers, the deleterious effects of the chlorinated effluent were clearly evident. At Umsunduze Site 3 and Umbilo Site 5 (both immediately downstream from the chlorinated effluent) both the number of taxa and number of individuals were substantially reduced, sometimes to zero. Where organisms were found at the next sites downstream (Sites 4 and 6 respectively), the samples were dominated by Chironomus. In contrast, the unchlorinated effluent in the Umbilo River caused very little difference in community structure. As predicted, B. harrisoni was not found in downstream samples in which chlorine was present, yet appeared to be relatively unaffected by the unchlorinated effluent, suggesting that chlorine, rather than the effluent was responsible for its absence at downstream sites. In conclusion, it would appear that while treated sewage effluent certainly causes changes in macroinvertebrate community structure, chlorination of this effluent leads to large scale destruction of the riverine community. This in turn delays the recovery process of the river, rendering a longer stretch unfit for use. The consequences of this delayed recovery are that the failure to meet the water quality requirements of the natural environment results in those of the other water users (agriculture, industry, domestic and recreation) not being met. This reduces the natural capacity of the riverine community to process organic waste and recover from the discharge of sewage effluent. Chlorination increases the distance of impaired water quality and environmental integrity which result from organically enriched treated sewage effluent. The results of the study indicated that the draft water quality guidelines for aquatic ecosystems, derived from inadequate data, and calculated with a safety factor, were the correct order of magnitude. The approach followed in the study will be useful in the development and refinement of water quality guidelines for aquatic ecosystems.
- Full Text:
- Date Issued: 1997
Corporate taxes and the taxation of dividends
- Authors: Williams, John Mark
- Date: 1997
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:890 , http://hdl.handle.net/10962/d1001644
- Description: The classical system of taxation, whereby companies are taxed without a deduction for dividends paid and shareholders are taxed on their dividend receipts, results in double taxation of dividends. Split rate and imputation systems have been developed in an attempt to mitigate the effects of double taxation of dividends. Double taxation of dividends and differences between corporate and maximum individual marginal tax rates result in corporate tax systems lacking neutrality. Distortions arise between organisational forms, between debt and equity financing and between the retention and distribution of profits. Various methods of integrating corporate and individual taxes have been advocated to overcome the lack of neutrality caused by corporate taxes. Following the introduction of the South African Income Tax Act in 1914, a number of taxes relating to dividends have existed. These have included a Dividend Tax, Non-resident Shareholder's Tax, Undistributed Profits Tax and Secondary Tax on Companies, hereafter referred to as STC. STC is a tax on net dividends declared and results in distributed income being taxed at higher rates than retained income. Despite the implementation of group relief provisions, STC results in an inhibition on the reinvestment of profits within the context of a group of companies. It is also a major cause of the lack of neutrality of the South African corporate tax system. As a result of the lack of neutrality and inhibition of group reinvestment caused by STC, a full imputation system is suggested as an alternative to replace STC.
- Full Text:
- Date Issued: 1997
- Authors: Williams, John Mark
- Date: 1997
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:890 , http://hdl.handle.net/10962/d1001644
- Description: The classical system of taxation, whereby companies are taxed without a deduction for dividends paid and shareholders are taxed on their dividend receipts, results in double taxation of dividends. Split rate and imputation systems have been developed in an attempt to mitigate the effects of double taxation of dividends. Double taxation of dividends and differences between corporate and maximum individual marginal tax rates result in corporate tax systems lacking neutrality. Distortions arise between organisational forms, between debt and equity financing and between the retention and distribution of profits. Various methods of integrating corporate and individual taxes have been advocated to overcome the lack of neutrality caused by corporate taxes. Following the introduction of the South African Income Tax Act in 1914, a number of taxes relating to dividends have existed. These have included a Dividend Tax, Non-resident Shareholder's Tax, Undistributed Profits Tax and Secondary Tax on Companies, hereafter referred to as STC. STC is a tax on net dividends declared and results in distributed income being taxed at higher rates than retained income. Despite the implementation of group relief provisions, STC results in an inhibition on the reinvestment of profits within the context of a group of companies. It is also a major cause of the lack of neutrality of the South African corporate tax system. As a result of the lack of neutrality and inhibition of group reinvestment caused by STC, a full imputation system is suggested as an alternative to replace STC.
- Full Text:
- Date Issued: 1997
Assessment of amoxycillin suppositories
- Authors: Webster, Jessica Angela
- Date: 1997
- Subjects: Solid dosage forms , Suppositories , Amoxicillin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3802 , http://hdl.handle.net/10962/d1003280 , Solid dosage forms , Suppositories , Amoxicillin
- Description: The investigations in this dissertation have been 'conducted to investigate the formulation and analysis of a paediatric amoxycillin suppository. The oral administration of antibiotics to young children can at times be roblematic. Compliance is sometimes poor because of a sore throat, nausea, vomiting, a high fever or a dislike for the taste or smell of the medicine:- In-such cases the rectal administration of an antibiotic could provide an alternative route of administration that avoids some of the problems that affect oral administration. Difficulties associated with rectal administration are bioavailability, local irritation, acceptability to patients and rejection of the dosage form. Few data, however, are available on the usefulness in children of suppositories in general, and antibiotic suppositories in particular. The areas of investigation have included the formulation of an amoxycillin suppository in various fatty bases, the quantitation of amoxycillin in both aqueous solution and human serum, assessment of stability of amoxycillin in stored aqueous and biological samples, in vitro drug release testing of suppositories, and bioavailability and pharmacokinetics following administration to human subjects of capsule, suppository, oral suspension and rectal suspension dosage forms. Suppositories containing 250 mg amoxycillin were prepared in theobroma oil and in the semisynthetic bases Witepso[ W35, Suppocire A32, Novata BD and Novata 299. The in vitro release characteristics of amoxycillin from these lipophilic suppository formulations were investigated using the USP rotating basket method. The dissolution of a drug from a solid dosage unit is an important parameter affecting drug bioavialability. High Performance Liquid Chromatography (HPLC) was used as the main analytical technique. An original HPLC method for analysis of amoxycillin in aqueous solution, using ultraviolet detection at 230 nm was develcfped. The validated method was a~plied to the determination of the stability of aqueous amoxycillin solutions, and was utilized to determine the amount of drug released during dissolution testing. Differential scanning calorimetry (DSC) is a technique commonly used in preformulation studies. Dissolution testing was used in conjunction with DSC to select a suppository base suitable for formulation with amoxycillin trihydrate. An HPLC method for analysis of amoxycillin in human serum using UV detection at 230 nm is presented. The method involves a solid phase extraction procedure followed by chromatography on a reversed phase column. The limit of sensitivity of 0.3 ILg/mL in serum is sufficiently sensitive to monitor serum concentrations of amoxycillin in humans after the administration of a single 250 mg oral dose. Pharmacokinetic parameters were calculated from data obtained following the administration of a capsule and oral suspension. These parameters were consistent with previously published results. Following administration of a lipophilic suppository and a rectal suspension, to human volunteers, it was concluded that amoxycillin trihydrate is not readily absorbed from the rectum. Further investigations into the modification of the suppository dosage form with absorption enhancers to improve rectal absorption of amoxycillin, as well as elucidation of the mechanism of absorption of the drug, could assist in improving this formulation so that it is suitable for paediatric use.
- Full Text:
- Date Issued: 1997
- Authors: Webster, Jessica Angela
- Date: 1997
- Subjects: Solid dosage forms , Suppositories , Amoxicillin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3802 , http://hdl.handle.net/10962/d1003280 , Solid dosage forms , Suppositories , Amoxicillin
- Description: The investigations in this dissertation have been 'conducted to investigate the formulation and analysis of a paediatric amoxycillin suppository. The oral administration of antibiotics to young children can at times be roblematic. Compliance is sometimes poor because of a sore throat, nausea, vomiting, a high fever or a dislike for the taste or smell of the medicine:- In-such cases the rectal administration of an antibiotic could provide an alternative route of administration that avoids some of the problems that affect oral administration. Difficulties associated with rectal administration are bioavailability, local irritation, acceptability to patients and rejection of the dosage form. Few data, however, are available on the usefulness in children of suppositories in general, and antibiotic suppositories in particular. The areas of investigation have included the formulation of an amoxycillin suppository in various fatty bases, the quantitation of amoxycillin in both aqueous solution and human serum, assessment of stability of amoxycillin in stored aqueous and biological samples, in vitro drug release testing of suppositories, and bioavailability and pharmacokinetics following administration to human subjects of capsule, suppository, oral suspension and rectal suspension dosage forms. Suppositories containing 250 mg amoxycillin were prepared in theobroma oil and in the semisynthetic bases Witepso[ W35, Suppocire A32, Novata BD and Novata 299. The in vitro release characteristics of amoxycillin from these lipophilic suppository formulations were investigated using the USP rotating basket method. The dissolution of a drug from a solid dosage unit is an important parameter affecting drug bioavialability. High Performance Liquid Chromatography (HPLC) was used as the main analytical technique. An original HPLC method for analysis of amoxycillin in aqueous solution, using ultraviolet detection at 230 nm was develcfped. The validated method was a~plied to the determination of the stability of aqueous amoxycillin solutions, and was utilized to determine the amount of drug released during dissolution testing. Differential scanning calorimetry (DSC) is a technique commonly used in preformulation studies. Dissolution testing was used in conjunction with DSC to select a suppository base suitable for formulation with amoxycillin trihydrate. An HPLC method for analysis of amoxycillin in human serum using UV detection at 230 nm is presented. The method involves a solid phase extraction procedure followed by chromatography on a reversed phase column. The limit of sensitivity of 0.3 ILg/mL in serum is sufficiently sensitive to monitor serum concentrations of amoxycillin in humans after the administration of a single 250 mg oral dose. Pharmacokinetic parameters were calculated from data obtained following the administration of a capsule and oral suspension. These parameters were consistent with previously published results. Following administration of a lipophilic suppository and a rectal suspension, to human volunteers, it was concluded that amoxycillin trihydrate is not readily absorbed from the rectum. Further investigations into the modification of the suppository dosage form with absorption enhancers to improve rectal absorption of amoxycillin, as well as elucidation of the mechanism of absorption of the drug, could assist in improving this formulation so that it is suitable for paediatric use.
- Full Text:
- Date Issued: 1997
Urban agriculture: advocacy and practice: a discursive study with particular reference to three Eastern Cape centres
- Authors: Webb, Nigel Leigh
- Date: 1997
- Subjects: Urban agriculture -- South Africa -- Eastern Cape Land use, Urban -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2095 , http://hdl.handle.net/10962/d1002658
- Description: The purpose of this thesis is to explain the continued advocacy of 'urban agriculture' (UA) in the literature in the face of the seemingly modest role played by cultivation in practice. The analytical framework adopted isrthat of discourse, the theoretical underpinnings of which are derived from the early works of Foucault, and applications such as those of Escobar (1989; 1991) and Ferguson (1990). Using a discursive orientation involves two main tasks - an explanation of how 'UA' has gained some prominence and the man~er in which its currency is able to be maintained. The investigation included an in-depth analysis of the literature and empirical research in th!"e~Eastern Cape centres. The function of the empirical findings is to expose the discourse, as well as to extend the empirical base relating to 'urban agricultural' research in general. The thesis suggests that the growth in interest in 'UA' is a result of a Foucaultian "gap" opening in the discourse. Changes in the conceptualisation of development, the rise-in prominence of the urban poor and emerging ecodevelopment views, among others, have given proponents of "UA' greater room for manoeuvre. However, most case studies promote 'UA' despite providing little evidence of its role in household welfare. The way the discourse maintains its' currency is in the manner in which the objects of 'UA' are constituted. Firstly, the people are characterised as poor, largely divorced from their rural origins, and mainly female. Each of these assertions is questioned on the basis of the literature itself and the empirical findings. Secondly, in the practice of cultivation, emphasis is placed on the inputs used, and the crops that are produced. The treatment of both the inputs and the crops by the literature is cursory. Investigations show that land availability, garden size and irrigation water are e~pecially problematic and vegetable consumption remains low. Four types of alleged benefit associated with 'UA' are analysed - environmental and ecological, psychological and social, financial, and nutritional. In each case commonly held assumptions are undermined by closer investigation. Thus, the thesis contends that the role played by cultivation is a modest one. Most of the claims made on behalf of 'UA' are more congruent with development discourse than actual cultivation practice.
- Full Text:
- Date Issued: 1997
- Authors: Webb, Nigel Leigh
- Date: 1997
- Subjects: Urban agriculture -- South Africa -- Eastern Cape Land use, Urban -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2095 , http://hdl.handle.net/10962/d1002658
- Description: The purpose of this thesis is to explain the continued advocacy of 'urban agriculture' (UA) in the literature in the face of the seemingly modest role played by cultivation in practice. The analytical framework adopted isrthat of discourse, the theoretical underpinnings of which are derived from the early works of Foucault, and applications such as those of Escobar (1989; 1991) and Ferguson (1990). Using a discursive orientation involves two main tasks - an explanation of how 'UA' has gained some prominence and the man~er in which its currency is able to be maintained. The investigation included an in-depth analysis of the literature and empirical research in th!"e~Eastern Cape centres. The function of the empirical findings is to expose the discourse, as well as to extend the empirical base relating to 'urban agricultural' research in general. The thesis suggests that the growth in interest in 'UA' is a result of a Foucaultian "gap" opening in the discourse. Changes in the conceptualisation of development, the rise-in prominence of the urban poor and emerging ecodevelopment views, among others, have given proponents of "UA' greater room for manoeuvre. However, most case studies promote 'UA' despite providing little evidence of its role in household welfare. The way the discourse maintains its' currency is in the manner in which the objects of 'UA' are constituted. Firstly, the people are characterised as poor, largely divorced from their rural origins, and mainly female. Each of these assertions is questioned on the basis of the literature itself and the empirical findings. Secondly, in the practice of cultivation, emphasis is placed on the inputs used, and the crops that are produced. The treatment of both the inputs and the crops by the literature is cursory. Investigations show that land availability, garden size and irrigation water are e~pecially problematic and vegetable consumption remains low. Four types of alleged benefit associated with 'UA' are analysed - environmental and ecological, psychological and social, financial, and nutritional. In each case commonly held assumptions are undermined by closer investigation. Thus, the thesis contends that the role played by cultivation is a modest one. Most of the claims made on behalf of 'UA' are more congruent with development discourse than actual cultivation practice.
- Full Text:
- Date Issued: 1997
Idolatry and the artist's role with special reference to the work and thought of Andy Warhol
- Authors: Waterkeyn, Linda Catherine
- Date: 1997
- Subjects: Warhol, Andy, 1928-1987 -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2425 , http://hdl.handle.net/10962/d1002221
- Description: This thesis uses Hirsch's dual notion of intention, i. e. conscious, intentional meaning and symptomatic, unconscious meaning, in order to avoid a dead end in the critical assessment of Warhol's work. T.S. Eliot's term "objective correlative" refers to a phenomenon whereby "an inner emotional reality" is evoked by its "external equivalent". (Benet, 1965). Thus, given that no work of art is purely self-referential (as distinct from its being autonomous),Hirsch's notion allows that viewerreconstruction of a painting involves shared values and concerns; that a painting reconstructed by a viewer acquires the status of an icon through which the viewer participates in the artist's sacred cosmos. Sociology of art tends on the whole to extrapolate from actual works to the alleged conditions that gave rise to them. That it cannot predict what specific works will arise from given conditions makes it unscientific. However, its usefulness lies in its ability to reveal what values and concerns are shared by artist and viewer. This is vital for an interpretation of Warhol's work. Warhol's biography leads directly into the meaning of his work. The sickly child of an immigrant steelworker, he grew up in Pittsburgh - an epitome of the technocratic-industrial environment - and was exposed from an early age to a violent and ugly world where the disparity between the super-wealthy and the struggling workers was deeply disturbing. That Warhol himself became a multi-millionaire artistic tycoon is significant, for it means that his works, his icons, were participatory in the very cultural myths and neuroses they appear to display or even despise. That his work has meaning and is open to interpretation there is no doubt. For example, a man-made soup can, as a manifestation and containment of the sacred, is coercive. Here the sacred becomes familiar, affordable and disposable. An electric chair, a man-made instrument of death, gives man supremacy over mortality and the divine prerogative of purging the world of all evil. The essay, however, does not attempt to answer the broader questions raised by Fromm and Roszak about the spiritual emptiness of the twentieth century and the existential crises experienced by those who hunger for meaning and fasten greedily onto anything that seems to proffer a glimpse of something beyond. The essay, nevertheless, strives within this context to elucidate the valid in Warhol's work
- Full Text:
- Date Issued: 1997
- Authors: Waterkeyn, Linda Catherine
- Date: 1997
- Subjects: Warhol, Andy, 1928-1987 -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2425 , http://hdl.handle.net/10962/d1002221
- Description: This thesis uses Hirsch's dual notion of intention, i. e. conscious, intentional meaning and symptomatic, unconscious meaning, in order to avoid a dead end in the critical assessment of Warhol's work. T.S. Eliot's term "objective correlative" refers to a phenomenon whereby "an inner emotional reality" is evoked by its "external equivalent". (Benet, 1965). Thus, given that no work of art is purely self-referential (as distinct from its being autonomous),Hirsch's notion allows that viewerreconstruction of a painting involves shared values and concerns; that a painting reconstructed by a viewer acquires the status of an icon through which the viewer participates in the artist's sacred cosmos. Sociology of art tends on the whole to extrapolate from actual works to the alleged conditions that gave rise to them. That it cannot predict what specific works will arise from given conditions makes it unscientific. However, its usefulness lies in its ability to reveal what values and concerns are shared by artist and viewer. This is vital for an interpretation of Warhol's work. Warhol's biography leads directly into the meaning of his work. The sickly child of an immigrant steelworker, he grew up in Pittsburgh - an epitome of the technocratic-industrial environment - and was exposed from an early age to a violent and ugly world where the disparity between the super-wealthy and the struggling workers was deeply disturbing. That Warhol himself became a multi-millionaire artistic tycoon is significant, for it means that his works, his icons, were participatory in the very cultural myths and neuroses they appear to display or even despise. That his work has meaning and is open to interpretation there is no doubt. For example, a man-made soup can, as a manifestation and containment of the sacred, is coercive. Here the sacred becomes familiar, affordable and disposable. An electric chair, a man-made instrument of death, gives man supremacy over mortality and the divine prerogative of purging the world of all evil. The essay, however, does not attempt to answer the broader questions raised by Fromm and Roszak about the spiritual emptiness of the twentieth century and the existential crises experienced by those who hunger for meaning and fasten greedily onto anything that seems to proffer a glimpse of something beyond. The essay, nevertheless, strives within this context to elucidate the valid in Warhol's work
- Full Text:
- Date Issued: 1997
Regulation of tryptophan-2,3-dioxygenase and pineal indoleamines by selected tryptophan derivatives and antidepressants
- Authors: Walsh, Harold Archibold
- Date: 1997
- Subjects: Antidepressants Tryptophan -- Physiological effect Tryptophan -- Therapeutic use Depression, Mental -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4017 , http://hdl.handle.net/10962/d1004077
- Description: The regulation of tryptophan-2,3-dioxygenase (TDO) (EC 1.13.1.12) and, to a lesser extent, pineal indoleamines, both in vitro and in vivo, is examined in this study. Rat liver TDO is a cytosolic enzyme which plays a crucial role in the regulation of circulating tryptophan (TRP) levels. Stimulation of this enzyme by heme enhances the catabolism of TRP, making less TRP available for uptake into the brain and other tissues, and for protein synthesis. At pH 7, the enzyme has an approximate Km of 100μM, is subject to substrate inhibition immediately beyond Sopt([S] at Vmax), and response of the enzyme is cooperative in both uninhibited and inhibited regions. Hill analysis of the uninhibited region reveals a biphasic plot and two classes of binding sites. Negative cooperativity is brought about through deprotonation of the enzyme. Substrate iphibition also occurs at both acidic and basic pH values with concomitant shifts in Sopt. The results obtained indicate that substrate inhibition could be an additional mechanism whereby the flux through the TRP-kynurenine pathway is regulated. TDO is subject to a diurnal rhythm, with peak activity during the pre-dark period and the loweSt activity towards the end of the dark period. It is possible that the enzyme controls the synthesis of the neurotransmitter serotonin (5-HT), and that the circadian rhythm in TDO activity is due to the endogenous rhythm of melatonin (aMT) production by the pineal gland. In the present study, aMT displaces TRP from bovine serum albumin (BSA) in vitro, and it is therefore possible for the indoleamine to regulate the availability of TRP for uptake into the brain for conversion to its derivatives. Chronic intraperitoneal administration of aMT affects physiological hepatic parameters in rats, such as TDO activity and stromal fatty acid composition, whilst no observable effect is demonstrable with respect to protein synthesis, nucleic acid metabolism, membrane fatty acid composition and pineal indole biosynthesis. On the other hand, chronic treatment of rats with antidepressants, the tricyclic desmethylimipramine (DMI) and the selective serotonin reuptake inhibitor (SSRI), fluoxetine, reveals significant negative alterations in TDO concentrations and pineal indole amine synthesis. Combining aMT with any of these two drugs normalises the activity of the hepatic enzyme. DMI is found to be an effective inhibitor of TDO in the micromolar range in vitro, and also affects total enzyme concentrations in vivo. Fluoxetine has no effect on TDO in vitro, but in vivo also reduces total enzyme levels in the liver. However, the SSRI does not affect conjugation between apo- and holoenzyme. Instead, it decreases extant holoenzyme levels. Indoleamine synthesis by the pineal gland, in organ culture, is altered by both antidepressants, although in different ways. DMI increases N-acetylserotonin levels and reduces the output of methoxyindole acetic acid and meth6xytryptophol. Fluoxetine treatment markedly reduces aMT concentrations and also brings about high levels of the 5-HT catabolites, 5-hydroxytryptophol and 5-hydroxyindole acetic acid. Insulin also lowers aMT synthesis significantly in pineal organ cultures, via a mechamsm that involves inhibition of the enzyme, N-acetyl transferase, that regulates aMT synthesis. The effects of insulin on pineal indole metabolism are due to the observation that a carbohydrate rich diet which induces insulin release elevates plasma TRP and brain 5-HT, but has no effect on pineal TRP and indole amine synthesis. It could thus be possible for insulin to have an effect on the pineal, since the latter is outside the blood brain barrier. The finilings of this study support the biogenic amine deficiency hypothesis, implicating some of the major biogenic amines such as noradrenaline (NA), 5-HT and aMT in depression. There is believed to be a deficiency of NA and 5-HT at their respective synapses in the depressed state. The drug DMI could act, firstly, by inhibiting TDO and thus increasing plasma TRP levels, and could, secondly, stimulate NA release and inhibit NA reuptake at the pineal membrane. The combined effect would be to enhance aMT synthesis, with eventual remission. Fluoxetine, on the other hand, appears to utilize a slightly different mode of action to DMI, which seems to focus on the preservation of 5-HT. The fact that aMT counteracts the effects of both antidepressants, and restores the activity of TDO to that of the controls, is also consistent with the observation that the therapeutic action of drugs such as these coincides willi the restoration of normal plasma levels of the neurohormone in depressives. In view of the biogenic amine deficiency hypothesis of depression and the contentious claim that TDO is the major peripheral determinant of brain TRP, brain 5-HT and ultimately aMT, the regulation of TDO is investigated and discussed. The study concludes that TDO activity is regulated by a number of endogenous compounds which are mainly derivatives of TRP, such as aMT and oxidized nicotinamide adenine dinucleotide and exogenous substances, of which DMI and fluoxetine are but two. In addition, modulation of IDO activity in depression appears to be an important aspect of antidepressant action. aMT, the product of the pineal gland, also has the potential to increase plasma TRP and hence forebrain TRP levels, and ultimately 5-HT concentrations, firstly by displacing TRP from serum albumin and secondly by inhibiting TDO.
- Full Text:
- Date Issued: 1997
- Authors: Walsh, Harold Archibold
- Date: 1997
- Subjects: Antidepressants Tryptophan -- Physiological effect Tryptophan -- Therapeutic use Depression, Mental -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4017 , http://hdl.handle.net/10962/d1004077
- Description: The regulation of tryptophan-2,3-dioxygenase (TDO) (EC 1.13.1.12) and, to a lesser extent, pineal indoleamines, both in vitro and in vivo, is examined in this study. Rat liver TDO is a cytosolic enzyme which plays a crucial role in the regulation of circulating tryptophan (TRP) levels. Stimulation of this enzyme by heme enhances the catabolism of TRP, making less TRP available for uptake into the brain and other tissues, and for protein synthesis. At pH 7, the enzyme has an approximate Km of 100μM, is subject to substrate inhibition immediately beyond Sopt([S] at Vmax), and response of the enzyme is cooperative in both uninhibited and inhibited regions. Hill analysis of the uninhibited region reveals a biphasic plot and two classes of binding sites. Negative cooperativity is brought about through deprotonation of the enzyme. Substrate iphibition also occurs at both acidic and basic pH values with concomitant shifts in Sopt. The results obtained indicate that substrate inhibition could be an additional mechanism whereby the flux through the TRP-kynurenine pathway is regulated. TDO is subject to a diurnal rhythm, with peak activity during the pre-dark period and the loweSt activity towards the end of the dark period. It is possible that the enzyme controls the synthesis of the neurotransmitter serotonin (5-HT), and that the circadian rhythm in TDO activity is due to the endogenous rhythm of melatonin (aMT) production by the pineal gland. In the present study, aMT displaces TRP from bovine serum albumin (BSA) in vitro, and it is therefore possible for the indoleamine to regulate the availability of TRP for uptake into the brain for conversion to its derivatives. Chronic intraperitoneal administration of aMT affects physiological hepatic parameters in rats, such as TDO activity and stromal fatty acid composition, whilst no observable effect is demonstrable with respect to protein synthesis, nucleic acid metabolism, membrane fatty acid composition and pineal indole biosynthesis. On the other hand, chronic treatment of rats with antidepressants, the tricyclic desmethylimipramine (DMI) and the selective serotonin reuptake inhibitor (SSRI), fluoxetine, reveals significant negative alterations in TDO concentrations and pineal indole amine synthesis. Combining aMT with any of these two drugs normalises the activity of the hepatic enzyme. DMI is found to be an effective inhibitor of TDO in the micromolar range in vitro, and also affects total enzyme concentrations in vivo. Fluoxetine has no effect on TDO in vitro, but in vivo also reduces total enzyme levels in the liver. However, the SSRI does not affect conjugation between apo- and holoenzyme. Instead, it decreases extant holoenzyme levels. Indoleamine synthesis by the pineal gland, in organ culture, is altered by both antidepressants, although in different ways. DMI increases N-acetylserotonin levels and reduces the output of methoxyindole acetic acid and meth6xytryptophol. Fluoxetine treatment markedly reduces aMT concentrations and also brings about high levels of the 5-HT catabolites, 5-hydroxytryptophol and 5-hydroxyindole acetic acid. Insulin also lowers aMT synthesis significantly in pineal organ cultures, via a mechamsm that involves inhibition of the enzyme, N-acetyl transferase, that regulates aMT synthesis. The effects of insulin on pineal indole metabolism are due to the observation that a carbohydrate rich diet which induces insulin release elevates plasma TRP and brain 5-HT, but has no effect on pineal TRP and indole amine synthesis. It could thus be possible for insulin to have an effect on the pineal, since the latter is outside the blood brain barrier. The finilings of this study support the biogenic amine deficiency hypothesis, implicating some of the major biogenic amines such as noradrenaline (NA), 5-HT and aMT in depression. There is believed to be a deficiency of NA and 5-HT at their respective synapses in the depressed state. The drug DMI could act, firstly, by inhibiting TDO and thus increasing plasma TRP levels, and could, secondly, stimulate NA release and inhibit NA reuptake at the pineal membrane. The combined effect would be to enhance aMT synthesis, with eventual remission. Fluoxetine, on the other hand, appears to utilize a slightly different mode of action to DMI, which seems to focus on the preservation of 5-HT. The fact that aMT counteracts the effects of both antidepressants, and restores the activity of TDO to that of the controls, is also consistent with the observation that the therapeutic action of drugs such as these coincides willi the restoration of normal plasma levels of the neurohormone in depressives. In view of the biogenic amine deficiency hypothesis of depression and the contentious claim that TDO is the major peripheral determinant of brain TRP, brain 5-HT and ultimately aMT, the regulation of TDO is investigated and discussed. The study concludes that TDO activity is regulated by a number of endogenous compounds which are mainly derivatives of TRP, such as aMT and oxidized nicotinamide adenine dinucleotide and exogenous substances, of which DMI and fluoxetine are but two. In addition, modulation of IDO activity in depression appears to be an important aspect of antidepressant action. aMT, the product of the pineal gland, also has the potential to increase plasma TRP and hence forebrain TRP levels, and ultimately 5-HT concentrations, firstly by displacing TRP from serum albumin and secondly by inhibiting TDO.
- Full Text:
- Date Issued: 1997
The biology of two important by-catch skate species on the Agulhas Bank, South Africa
- Authors: Walmsley, Sarah Ann
- Date: 1997
- Subjects: Skates (Fishes) -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5240 , http://hdl.handle.net/10962/d1005083 , Skates (Fishes) -- South Africa -- Physiology
- Description: Members of the family Rajidae are common components of the demersal trawl fishery, contributing around 1% to the total catch. However, apart from a single species all South African rajids are currently discarded. With demands for new protein sources ever-increasing, it is possible that currently underutilised species, such as the skates will be utilized to a greater extent. Raja wallacei and R.pullopunctata are common trawler by-catch species, ranging along most of the South African coast. The current study allred to further knowledge on the population biology of both species through age and growth, reproductive and feeding studies. The study also allred to assess whether any of the South African skate species show the potential for utilization as a food source. Band counts of vertebral centra were used to determine growth parameters and generate growth curves for males and females of both species. Growth was significantly different between the sexes. In both cases, females grew slower than males but reached a greater asymptotic disc width. As with other elasmobranchs, R.wallacei and R.pullopunctata are long-lived and slow growing. As with all other skates, the study species are oviparous laying large, yolked eggs in tough, leathery cases on the sea bed. The onset of maturity occurs at a large size (approximately 400mm disc width (10-11 years of age) for R.wallacei and 600mm disc width (12-13 years of age) for Rpullopunctata) and is very rapid. The oldest R.wallacei and R.pullopunctata observed were 16 and 18 years of age, respectively. No distinct breeding season was determined and no nursery areas were observed. A large proportion of individuals, especially R.pullopunctata was immature. Both species fed primarily on crustaceans and teleosts with an ontogenetic shift in diet from mysids, amphipods, isopods and bregmatocerids to larger Gnathophis sp., Mursia cristimanus and carid shrimps. Large discrepancies were seen in the diet of animals spatially, temporally and between research and commercially-caught animals. Disc-width frequency data was limited but suggested that both species show preference for depths of 100-300m. Size distribution did not appear to be affected by depth, although the data set was limited. A paucity of large individuals in the catch may indicate that stocks are suffering from growth overfishing by trawling operations. Historical and observer data showed that although skates are common components of the by-catch, the potential for greater use is limited. The biscuit skate, R.straeleni, on the west coast is the only species that could be better utilized. If skates are treated as a single group the potential is increased but this causes problems in assessing stocks.
- Full Text:
- Date Issued: 1997
- Authors: Walmsley, Sarah Ann
- Date: 1997
- Subjects: Skates (Fishes) -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5240 , http://hdl.handle.net/10962/d1005083 , Skates (Fishes) -- South Africa -- Physiology
- Description: Members of the family Rajidae are common components of the demersal trawl fishery, contributing around 1% to the total catch. However, apart from a single species all South African rajids are currently discarded. With demands for new protein sources ever-increasing, it is possible that currently underutilised species, such as the skates will be utilized to a greater extent. Raja wallacei and R.pullopunctata are common trawler by-catch species, ranging along most of the South African coast. The current study allred to further knowledge on the population biology of both species through age and growth, reproductive and feeding studies. The study also allred to assess whether any of the South African skate species show the potential for utilization as a food source. Band counts of vertebral centra were used to determine growth parameters and generate growth curves for males and females of both species. Growth was significantly different between the sexes. In both cases, females grew slower than males but reached a greater asymptotic disc width. As with other elasmobranchs, R.wallacei and R.pullopunctata are long-lived and slow growing. As with all other skates, the study species are oviparous laying large, yolked eggs in tough, leathery cases on the sea bed. The onset of maturity occurs at a large size (approximately 400mm disc width (10-11 years of age) for R.wallacei and 600mm disc width (12-13 years of age) for Rpullopunctata) and is very rapid. The oldest R.wallacei and R.pullopunctata observed were 16 and 18 years of age, respectively. No distinct breeding season was determined and no nursery areas were observed. A large proportion of individuals, especially R.pullopunctata was immature. Both species fed primarily on crustaceans and teleosts with an ontogenetic shift in diet from mysids, amphipods, isopods and bregmatocerids to larger Gnathophis sp., Mursia cristimanus and carid shrimps. Large discrepancies were seen in the diet of animals spatially, temporally and between research and commercially-caught animals. Disc-width frequency data was limited but suggested that both species show preference for depths of 100-300m. Size distribution did not appear to be affected by depth, although the data set was limited. A paucity of large individuals in the catch may indicate that stocks are suffering from growth overfishing by trawling operations. Historical and observer data showed that although skates are common components of the by-catch, the potential for greater use is limited. The biscuit skate, R.straeleni, on the west coast is the only species that could be better utilized. If skates are treated as a single group the potential is increased but this causes problems in assessing stocks.
- Full Text:
- Date Issued: 1997
Environmental education : a strategy for primary teacher education
- Authors: Wagiet, Razeena
- Date: 1997
- Subjects: Environmental education -- Study and teaching (Elementary) Environmental education -- Study and teaching (Elementary) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1512 , http://hdl.handle.net/10962/d1003394
- Description: This research focuses on environmental education in initial teacher education, and is grounded in three interlinked and widely recognised assumptions. First, that education for sustainable living can assist in resolving some environmental problems that are contributing to the environmental crises of sustainability currently facing South Africa and the rest of the world. Second, that education for sustainable living can assist in the establishment of a new environmental ethic that will foster a sustainable way of living. Third, that teacher education is a vital process for the attainment of both. These assumptions inform the aim of this research, which is to explore the potential for the implementation of education for sustainable living, and to identify a strategy for this, for initial teacher education, for senior primary school student teachers in the Western Cape. The strategy is derived following the grounded theory approach, developed through the case study method. In the process of identifying the strategy, this study establishes that there are challenges at macro, meso and micro levels that are obstructing the changes necessary for education for sustainable living. Change theory provides the basis for explaining these shortcomings, by helping to identify the barriers that might obstruct the realisation of the changes that are necessary for education for sustainable living. These challenges need to be perceived in the light of overcoming three sets of barriers in the way of the potential implementation of education for sustainable living in teacher education. First are those that can be ascribed to the formal education system that, while clinging to Western, Eurocentric values on the one hand, bave also failed to secure a policy for environmental education on the other. Second are the barriers ascribed to the teacher educators themselves, with the whole notion of their powerlessness at its core. Finally, there are the logistical barriers, which encompass, for example, time and financial constraints. With these barriers as a backdrop, to facilitate the incorporation of environmental education into initial teacher education, the study identifies a need for the development of a strategy to secure that education for sustainable living assumes its rightful place in the curriculum for initial teacher education. This framework emerges from the theory grounded in the interviewees' responses during the research, and from the theory grounded in the literature. Central to this framework is for education for sustainable living to contribute to the realisation of real change, change that would further the transformation of our conflict-riddled and inequitable society towards a more democratic and just one. This thesis demonstrates that the realisation of the changes necessary for education for sustainable living demand a reconstruction of current teacher education in order to secure and to sustain an appropriate and sound education ethic to form the basis of a trans formative teacher education curriculum for sustainable living within initial teacher education. Except formal policy, but central to overcoming these barriers, is the need for professional development programmes for teacher educators. A strategy in this regard, is outlined.
- Full Text:
- Date Issued: 1997
- Authors: Wagiet, Razeena
- Date: 1997
- Subjects: Environmental education -- Study and teaching (Elementary) Environmental education -- Study and teaching (Elementary) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1512 , http://hdl.handle.net/10962/d1003394
- Description: This research focuses on environmental education in initial teacher education, and is grounded in three interlinked and widely recognised assumptions. First, that education for sustainable living can assist in resolving some environmental problems that are contributing to the environmental crises of sustainability currently facing South Africa and the rest of the world. Second, that education for sustainable living can assist in the establishment of a new environmental ethic that will foster a sustainable way of living. Third, that teacher education is a vital process for the attainment of both. These assumptions inform the aim of this research, which is to explore the potential for the implementation of education for sustainable living, and to identify a strategy for this, for initial teacher education, for senior primary school student teachers in the Western Cape. The strategy is derived following the grounded theory approach, developed through the case study method. In the process of identifying the strategy, this study establishes that there are challenges at macro, meso and micro levels that are obstructing the changes necessary for education for sustainable living. Change theory provides the basis for explaining these shortcomings, by helping to identify the barriers that might obstruct the realisation of the changes that are necessary for education for sustainable living. These challenges need to be perceived in the light of overcoming three sets of barriers in the way of the potential implementation of education for sustainable living in teacher education. First are those that can be ascribed to the formal education system that, while clinging to Western, Eurocentric values on the one hand, bave also failed to secure a policy for environmental education on the other. Second are the barriers ascribed to the teacher educators themselves, with the whole notion of their powerlessness at its core. Finally, there are the logistical barriers, which encompass, for example, time and financial constraints. With these barriers as a backdrop, to facilitate the incorporation of environmental education into initial teacher education, the study identifies a need for the development of a strategy to secure that education for sustainable living assumes its rightful place in the curriculum for initial teacher education. This framework emerges from the theory grounded in the interviewees' responses during the research, and from the theory grounded in the literature. Central to this framework is for education for sustainable living to contribute to the realisation of real change, change that would further the transformation of our conflict-riddled and inequitable society towards a more democratic and just one. This thesis demonstrates that the realisation of the changes necessary for education for sustainable living demand a reconstruction of current teacher education in order to secure and to sustain an appropriate and sound education ethic to form the basis of a trans formative teacher education curriculum for sustainable living within initial teacher education. Except formal policy, but central to overcoming these barriers, is the need for professional development programmes for teacher educators. A strategy in this regard, is outlined.
- Full Text:
- Date Issued: 1997
A phenomenological investigation into educational leaders' perceptions of themselves, their followers, and their organisational contexts
- Authors: Van der Mescht, Hennie
- Date: 1997
- Subjects: Educational leadership -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1697 , http://hdl.handle.net/10962/d1003580
- Description: Leadership is a richly researched ana widely covered topic, attracting the attention of virtually every discipline within the human sciences. Research which focuses on leadership within an educational context is, however, a relatively recent development. Most of the leadership research conducted in this century has been driven by the needs of industry. Consequently, leadership theories have tended to emphasise the instrumentality, measurability and effectiveness of leadership. Leadership models, intent on being prescriptive and 'learnable', have been inclined to oversimplify the complexity of the leadership phenomenon. Another factor which accounts for these features is the research approach adopted by researchers, which has largely been positivistic. This study is an attempt to investigate the underlying dynamics of educational leadership. It is an in-depth study of five educational leaders' perceptions of themselves as leaders, of the people with whom they interact, and of the organisations within which they work. The study is conducted along the lines suggested by phenomenology, a highly qualitative, anti-positivistic research approach, which encourages the researcher to set aside pre-conceived notions of the phenomenon, and to describe what is found exactly as it presents itself. My findings have highlighted a wide and richly varied range of psychological, emotional and cultural factors which seem to play significant roles in how leaders perceive themselves, others and their environments. Most of these factors have been either entirely ignored or very scantily covered in mainstream leadership literature. Educational leadership emerges as a complex, virtually undefinable phenomenon; new and challenging research approaches and methods have the potential for increasing our understanding of how leaders lead, which in turn will have implications for leadership education and selection.
- Full Text:
- Date Issued: 1997
- Authors: Van der Mescht, Hennie
- Date: 1997
- Subjects: Educational leadership -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1697 , http://hdl.handle.net/10962/d1003580
- Description: Leadership is a richly researched ana widely covered topic, attracting the attention of virtually every discipline within the human sciences. Research which focuses on leadership within an educational context is, however, a relatively recent development. Most of the leadership research conducted in this century has been driven by the needs of industry. Consequently, leadership theories have tended to emphasise the instrumentality, measurability and effectiveness of leadership. Leadership models, intent on being prescriptive and 'learnable', have been inclined to oversimplify the complexity of the leadership phenomenon. Another factor which accounts for these features is the research approach adopted by researchers, which has largely been positivistic. This study is an attempt to investigate the underlying dynamics of educational leadership. It is an in-depth study of five educational leaders' perceptions of themselves as leaders, of the people with whom they interact, and of the organisations within which they work. The study is conducted along the lines suggested by phenomenology, a highly qualitative, anti-positivistic research approach, which encourages the researcher to set aside pre-conceived notions of the phenomenon, and to describe what is found exactly as it presents itself. My findings have highlighted a wide and richly varied range of psychological, emotional and cultural factors which seem to play significant roles in how leaders perceive themselves, others and their environments. Most of these factors have been either entirely ignored or very scantily covered in mainstream leadership literature. Educational leadership emerges as a complex, virtually undefinable phenomenon; new and challenging research approaches and methods have the potential for increasing our understanding of how leaders lead, which in turn will have implications for leadership education and selection.
- Full Text:
- Date Issued: 1997
Music Universe
- Unknown
- Authors: Unknown
- Subjects: McGregor, Chris--1936-1990 , Brotherhood of Breath (Musical group) , Blue Notes (Musical group : South Africa) , Jazz
- Language: English
- Type: Article
- Identifier: vital:13734 , http://hdl.handle.net/10962/d1012748
- Description: Photocopied article from the New Zealand Jazziz Magazine about Maxine McGregor's book "Chris McGregor and The Brotherhood of Breath" (Bamberger Books).
- Full Text:
- Authors: Unknown
- Subjects: McGregor, Chris--1936-1990 , Brotherhood of Breath (Musical group) , Blue Notes (Musical group : South Africa) , Jazz
- Language: English
- Type: Article
- Identifier: vital:13734 , http://hdl.handle.net/10962/d1012748
- Description: Photocopied article from the New Zealand Jazziz Magazine about Maxine McGregor's book "Chris McGregor and The Brotherhood of Breath" (Bamberger Books).
- Full Text:
SA in the global economy
- TURP
- Authors: TURP
- Date: 1997
- Subjects: TURP
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/160942 , vital:40569
- Description: There are growing ties in the world between countries which coincides with current major social, political and economic restructuring. This is what many refer to as “globalisation”. Globalisation is a process which involves greater influence by global forces on individual countries such as South Africa. It means that global rules are being set which impact on: the policies of our government, the way companies in South Africa make their plans, the way that trade unions, community organisations and development organisations take up issues, and the way individuals make a living in the country. Globalisation has raised new and difficult issues for the labour movement and have thrown up new forms of struggle. Some of these issues have stumped and even demobilised some unionists in South Africa and internationally. Some feel that globalisation cannot be challenged and that there is no alternative. Others feel that we have not become powerless and that there are ways to fight its negative effects. Turp has published a book on these issues entitled, South Africa in the Global Economy: understanding the challenges, working towards alternatives. One of the main purposes of the book is to clarify what the new complex and challenging issues are. By doing this, we hope to clarify what we are up against.
- Full Text:
- Date Issued: 1997
- Authors: TURP
- Date: 1997
- Subjects: TURP
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/160942 , vital:40569
- Description: There are growing ties in the world between countries which coincides with current major social, political and economic restructuring. This is what many refer to as “globalisation”. Globalisation is a process which involves greater influence by global forces on individual countries such as South Africa. It means that global rules are being set which impact on: the policies of our government, the way companies in South Africa make their plans, the way that trade unions, community organisations and development organisations take up issues, and the way individuals make a living in the country. Globalisation has raised new and difficult issues for the labour movement and have thrown up new forms of struggle. Some of these issues have stumped and even demobilised some unionists in South Africa and internationally. Some feel that globalisation cannot be challenged and that there is no alternative. Others feel that we have not become powerless and that there are ways to fight its negative effects. Turp has published a book on these issues entitled, South Africa in the Global Economy: understanding the challenges, working towards alternatives. One of the main purposes of the book is to clarify what the new complex and challenging issues are. By doing this, we hope to clarify what we are up against.
- Full Text:
- Date Issued: 1997
Title not specified
- Three Lunyankole men, Tracey, Andrew T N
- Authors: Three Lunyankole men , Tracey, Andrew T N
- Date: 1997
- Subjects: Nyankole (African people) -- Uganda , Music -- Religious aspects , Harp , Drum music , Sub-Saharan African music , Africa Uganda Ankole f-ug
- Language: English
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/93405 , vital:30877 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC027-03
- Description: Church song accompanied by two harps and a drum.
- Full Text: false
- Date Issued: 1997
- Authors: Three Lunyankole men , Tracey, Andrew T N
- Date: 1997
- Subjects: Nyankole (African people) -- Uganda , Music -- Religious aspects , Harp , Drum music , Sub-Saharan African music , Africa Uganda Ankole f-ug
- Language: English
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/93405 , vital:30877 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC027-03
- Description: Church song accompanied by two harps and a drum.
- Full Text: false
- Date Issued: 1997
Share-net: a case study of environmental education resource material development in a risk society
- Authors: Taylor, Robert James
- Date: 1997
- Subjects: Environmental education Environmental education -- South Africa Environmental education -- Activity programs -- South Africa Environmental education -- South Africa -- Information resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1765 , http://hdl.handle.net/10962/d1003650
- Description: This narrative study reviews the development of Share-Net, an informal resource materials network, located within the developing environmental education activities of the Wildlife and Environment Society of South Africa. Historical shaping factors within the Society are discussed and changing views on conservation, environmental education and research are described. Rather than the research process being a utilitarian and outside endeavour for clarifying and monitoring, the research orientation of this study is one of grounded activity within and integrally part of processes of change. Within a developing story of resource materials and workshops, themes are traced and emergent tensions are critically reviewed. Teacher workshops from 1981 until 1995 are analysed and developing orientations are described. Within this review changes are evident from an orientation of 'us' informing 'them' to joint, collaborative endeavours within the development and use of resource materials. The study reviews and illuminates the Share-Net project around questions of project orientation and management and this is done through the narration of case studies. Principles and patterns emerging within these are examined to guide future resource development projects. Popularist notions of networking and structural functionalist notions of social change are also examined. Grand, modernist strategies designed to cause change in others are questioned and the role of small-scale nodes of resource material activity cooperating within an open network are clarified as useful alternatives. Local resourcing centres such as these have proved useful in supporting teachers in the development, use and adaptation of resource materials. The study also examines income and expenditure of the Share-Net project since 1988 to review economic sustainability. A case is made for sustaining the project conceptually and financially through the sales of products and services rather than through external donor sources. Finally the study raises questions and challenges within the project and proposes guiding frameworks for future review, in action, as the story continues.
- Full Text:
- Date Issued: 1997
- Authors: Taylor, Robert James
- Date: 1997
- Subjects: Environmental education Environmental education -- South Africa Environmental education -- Activity programs -- South Africa Environmental education -- South Africa -- Information resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1765 , http://hdl.handle.net/10962/d1003650
- Description: This narrative study reviews the development of Share-Net, an informal resource materials network, located within the developing environmental education activities of the Wildlife and Environment Society of South Africa. Historical shaping factors within the Society are discussed and changing views on conservation, environmental education and research are described. Rather than the research process being a utilitarian and outside endeavour for clarifying and monitoring, the research orientation of this study is one of grounded activity within and integrally part of processes of change. Within a developing story of resource materials and workshops, themes are traced and emergent tensions are critically reviewed. Teacher workshops from 1981 until 1995 are analysed and developing orientations are described. Within this review changes are evident from an orientation of 'us' informing 'them' to joint, collaborative endeavours within the development and use of resource materials. The study reviews and illuminates the Share-Net project around questions of project orientation and management and this is done through the narration of case studies. Principles and patterns emerging within these are examined to guide future resource development projects. Popularist notions of networking and structural functionalist notions of social change are also examined. Grand, modernist strategies designed to cause change in others are questioned and the role of small-scale nodes of resource material activity cooperating within an open network are clarified as useful alternatives. Local resourcing centres such as these have proved useful in supporting teachers in the development, use and adaptation of resource materials. The study also examines income and expenditure of the Share-Net project since 1988 to review economic sustainability. A case is made for sustaining the project conceptually and financially through the sales of products and services rather than through external donor sources. Finally the study raises questions and challenges within the project and proposes guiding frameworks for future review, in action, as the story continues.
- Full Text:
- Date Issued: 1997
The application of a landscape diversity index using remote sensing and geographical information systems to identify degradation patterns in the Great Fish River Valley, Eastern Cape Province, South Africa
- Authors: Tanser, Frank Courteney
- Date: 1997
- Subjects: Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4814 , http://hdl.handle.net/10962/d1005488 , Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Description: Using a range of satellite-derived indices I describe. monitor and predict vegetation conditions that exist in the Great Fish River Valley, Eastern Cape. The heterogeneous nature of the area necessitates that the mapping of vegetation classes be accomplished using a combination of a supervised approach, an unsupervised approach and the use of a Moving Standard Deviation Index (MSDI). Nine vegetation classes are identified and mapped at an accuracy of 84%. The vegetation classes are strongly related to land-use and the communal areas demonstrate a reduction in palatable species and a shift towards dominance by a single species. Nature reserves and commercial rangeland are by contrast dominated by good condition vegetation types. The Modified Soil Adjusted Vegetation Index (MSA VI) is used to map the vegetation production in the study area. The influence of soil reflectance is reduced using this index. The MSA VI proves to be a good predictor of vegetation condition in the higher rainfall areas but not in the more semi-arid regions. The MSA VI has a significant relationship to rainfall but no absolute relationship to biomass. However, a stratification approach (on the basis of vegetation type) reveals that the MSA VI exhibits relationships to biomass in vegetation types occurring in the higher rainfall areas and consisting of a large cover of shrubs. A technique based on an index which describes landscape spatial variability is presented to assist in the interpretation of landscape condition. The research outlines a method for degradation assessment which overcomes many of the problems associated with cost and repeatability. Indices that attempt to provide a correlation with net primary productivity, e.g. NDVI, do not consider changes in the quality of net primary productivity. Landscape variability represents a measure of ecosystem change in the landscape that underlies the degradation process. The hypothesis is that healthy/undisturbed/stable landscapes tend to be less variable and homogenous than their degraded heterogenous counterparts. The Moving Standard Deviation Index (MSDI) is calculated by performing a 3 x 3 moving standard deviation window across Landsat Thematic Mapper (TM) band 3. The result is a sensitive indicator of landscape condition which is not affected by moisture availability and vegetation type. The MSDI shows a significant negative relationship to NDVI confirming its relationship to condition. The cross-classification of MSDI with NDVI allows the identification of invasive woody weeds which exhibit strong photosynthetic signals and would therefore be categorised as good condition using NDVI. Other ecosystems are investigated to determine the relationship between NDVI and MSDI. Where increase in NDVI is disturbance-induced (such as the Kalahari Desert) the relationship is positive. Where high NDVI values are indicative of good condition rangeland (such as the Fish River Valley) the relationship is negative. The MSDI therefore always exhibits a significant positive relationship to degradation irrespective of the relationship of NDVI to condition in the ecosystem.
- Full Text:
- Date Issued: 1997
- Authors: Tanser, Frank Courteney
- Date: 1997
- Subjects: Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4814 , http://hdl.handle.net/10962/d1005488 , Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Description: Using a range of satellite-derived indices I describe. monitor and predict vegetation conditions that exist in the Great Fish River Valley, Eastern Cape. The heterogeneous nature of the area necessitates that the mapping of vegetation classes be accomplished using a combination of a supervised approach, an unsupervised approach and the use of a Moving Standard Deviation Index (MSDI). Nine vegetation classes are identified and mapped at an accuracy of 84%. The vegetation classes are strongly related to land-use and the communal areas demonstrate a reduction in palatable species and a shift towards dominance by a single species. Nature reserves and commercial rangeland are by contrast dominated by good condition vegetation types. The Modified Soil Adjusted Vegetation Index (MSA VI) is used to map the vegetation production in the study area. The influence of soil reflectance is reduced using this index. The MSA VI proves to be a good predictor of vegetation condition in the higher rainfall areas but not in the more semi-arid regions. The MSA VI has a significant relationship to rainfall but no absolute relationship to biomass. However, a stratification approach (on the basis of vegetation type) reveals that the MSA VI exhibits relationships to biomass in vegetation types occurring in the higher rainfall areas and consisting of a large cover of shrubs. A technique based on an index which describes landscape spatial variability is presented to assist in the interpretation of landscape condition. The research outlines a method for degradation assessment which overcomes many of the problems associated with cost and repeatability. Indices that attempt to provide a correlation with net primary productivity, e.g. NDVI, do not consider changes in the quality of net primary productivity. Landscape variability represents a measure of ecosystem change in the landscape that underlies the degradation process. The hypothesis is that healthy/undisturbed/stable landscapes tend to be less variable and homogenous than their degraded heterogenous counterparts. The Moving Standard Deviation Index (MSDI) is calculated by performing a 3 x 3 moving standard deviation window across Landsat Thematic Mapper (TM) band 3. The result is a sensitive indicator of landscape condition which is not affected by moisture availability and vegetation type. The MSDI shows a significant negative relationship to NDVI confirming its relationship to condition. The cross-classification of MSDI with NDVI allows the identification of invasive woody weeds which exhibit strong photosynthetic signals and would therefore be categorised as good condition using NDVI. Other ecosystems are investigated to determine the relationship between NDVI and MSDI. Where increase in NDVI is disturbance-induced (such as the Kalahari Desert) the relationship is positive. Where high NDVI values are indicative of good condition rangeland (such as the Fish River Valley) the relationship is negative. The MSDI therefore always exhibits a significant positive relationship to degradation irrespective of the relationship of NDVI to condition in the ecosystem.
- Full Text:
- Date Issued: 1997
Student-teachers' perspectives of the role of environmental education in geography education
- Authors: Symmonds, Joanne
- Date: 1997
- Subjects: Geography -- Study and teaching -- Environmental aspects Environmental education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1776 , http://hdl.handle.net/10962/d1003661
- Description: The ideas contained in socially critical Environmental Education cannot be ignored given the current environmental crisis and the need to achieve democracy in South African society. In order to achieve this learners need to develop the skills to make informed decisions which will facilitate the achievement of a sustainable society. It is the contention of this research that a socially critical Environmental Education approach to education can facilitate the above. Teachers of formal secondary school Geography Education are in the position to implement socially critical Environmental Education into their teaching. This study therefore investigates the perspectives of student teachers regarding the role of Environmental Education in secondary school Geography Education. This was done within the Interpretative Paradigm using a case study which involved five Higher Diploma in Education Geography method students. The research has revealed that even though the Geography method students have been exposed to an Environmental Education course, in their teaching preparation and are motivated to use it, they have limited understanding of the theory underpinning Environmental Education and how to apply it to their Geography teaching. The problems of bridging theory and practice was apparent. Recommendations are made as how to best facilitate the gap between theory and practice.
- Full Text:
- Date Issued: 1997
- Authors: Symmonds, Joanne
- Date: 1997
- Subjects: Geography -- Study and teaching -- Environmental aspects Environmental education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1776 , http://hdl.handle.net/10962/d1003661
- Description: The ideas contained in socially critical Environmental Education cannot be ignored given the current environmental crisis and the need to achieve democracy in South African society. In order to achieve this learners need to develop the skills to make informed decisions which will facilitate the achievement of a sustainable society. It is the contention of this research that a socially critical Environmental Education approach to education can facilitate the above. Teachers of formal secondary school Geography Education are in the position to implement socially critical Environmental Education into their teaching. This study therefore investigates the perspectives of student teachers regarding the role of Environmental Education in secondary school Geography Education. This was done within the Interpretative Paradigm using a case study which involved five Higher Diploma in Education Geography method students. The research has revealed that even though the Geography method students have been exposed to an Environmental Education course, in their teaching preparation and are motivated to use it, they have limited understanding of the theory underpinning Environmental Education and how to apply it to their Geography teaching. The problems of bridging theory and practice was apparent. Recommendations are made as how to best facilitate the gap between theory and practice.
- Full Text:
- Date Issued: 1997
Bioaccumulation of heavy metals by the yeast S. cerevisiae and the bioremediation of industrial waste water
- Authors: Stoll, Anita
- Date: 1997
- Subjects: Saccharomyces cerevisiae Yeast fungi -- Biotechnology Metal ions Bioremediation Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4015 , http://hdl.handle.net/10962/d1004075
- Description: Water is an essential element in all aspects of life and is vital for both domestic and industrial purposes regarding both the quality and quantity thereof. Similar to many other drought stricken countries, South Africa requires water for the socio-economic growth of the country, yet is faced with the problem of maintaining the quality of its drinking water as well as protecting the dwindling supplies. In an attempt to prevent the deterioration of South African water supplies the treatment, purification and recycling of industrial and mining waste water has recently become of prime importance. Many industrial and mining waste waters contain heavy metals in toxic quantities. The conventional processes that have been used till recently to address this problem, are often expensive or contain chemical agents which compound the environmental problem. As an alternative biological methods of metal accumulation appear to offer an economic and efficient alternative to these methods. An advantage to the South African scenario is the commercial production of the yeast, S. cerevisiae as a readily inexpensive by-product from some fermentation industries, Yeast cells, and in particular S. cerevisiae have proven to be capable of accumulating heavy metals, and therefore exhibit potential application in the bioremediation of waste water. The aim of this project was twofold. The initial part of this work attempted to define the mechanisms of metal accumulation by the yeast cells and cellular components. The information obtained from these initial studies provided a data base required for the development of a bioremediation system. Initial contact with the metal ions occurs at the wall interface of the yeast cell. Metal accumulation appears to be a function of all the cell wall components. The isolated cell wall components are better metal chelators then the intact cell walls. An apparent affinity series of mannan > chitin> glucan > intact cell walls exists. However, these components differ in their affinities for metal ions. Storage of metal ions within the cell occurs predominantly in the vacuole. The present study concluded that metal accumulation by the vacuole could be related to size. Metal accumulation occurred in the order of Cu2+ > Co2+ > Cd2+ with a corresponding decrease in atomic radii of Cd2+ > C02+ > Cu2+. Vacuolar ion deposition occurs at an early stage during the internalization of metal ions within the yeast cells. At the onset of vacuolar saturation, depositions of metal ions as granules within the cytosol occurs. In the presence of heavy metal cations viable yeast cells can be shown to exhibit two types of cellular responses. Uptake of Cu2+ and Cd2+ causes the loss of intracellular physiological cations from within the yeast cell. In comparison, uptake of Co2+ into the cell does not have this effect. All three heavy metal cations initiate plasma cell membrane permeability, thus the Cu2+ and Cd2+ induced loss of the intracellular cations, occurs. ~ a result of ion-exchange mechanisms and not due to cation leakage brought about by membrane permeabilization. Uptake of heavy metals by viable yeasts appears to be generally non-selective though the amount of metals accumulated are largely affected by the ratio of ambient metal concentration to biomass quantity. In addition, the energy dependent nature of internalization necessitates the availability of an external energy source for metal uptake by viable yeast cells. For these reasons metal removal from industrial waste water was investigated using non-viable biomass. By immobilizing the yeast cells additional mechanical integrity and stability was conferred apon the biomass. The three types of biomass preparations developed in this study, viz. polyvinyl alcohol (PV A) Na-alginate, PV A Na-orthophosphate and alkali treated polyethylenimine (PEI):glutaraldehyde (GA) biomass pellets, all fulfilled the necessary physical requirements. However, the superior metal accumulating properties of the PEI:GA biomass determined its selection as a biosorbent for bioremediation purposes. Biosorption of heavy metals by PEI:GA biomass is of a competitive nature, with the amount of metal accumulated influenced by the availability of the metal ions. This availability is largely determined by the solution pH. At low pH values the affinity of the biomass for metals decreases, whilst enhanced metal biosorption occurs at higher pHs, ego pH 4.5 - 6.0. PEI:GA biomass pellets can be implemented -as a biosorbent for the bi9remediaiton of high concentration, low-volume metal containing industrial waste. Several options regarding the bioremediation system are available. Depending on the concentration of the metals in the effluent, the bioremediation process can either be used independently or as part of a biphasic remediation system for the treatment of waste water. Initial phase chemical modification may be required, whilst two types of biological systems can be implemented as 'part of the second phase. The PEI:GA biomass can either be contained within continuous-flow fixed bed tanks or continuous-flow stirred bioreactor tanks. Due to the simplicity of the process and the ease with which scale-up is facilitated, the second type of system shows greater application potential for the treatment of this type of industrial waste water than the fixed-bed systems.
- Full Text:
- Date Issued: 1997
- Authors: Stoll, Anita
- Date: 1997
- Subjects: Saccharomyces cerevisiae Yeast fungi -- Biotechnology Metal ions Bioremediation Water -- Purification -- Biological treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4015 , http://hdl.handle.net/10962/d1004075
- Description: Water is an essential element in all aspects of life and is vital for both domestic and industrial purposes regarding both the quality and quantity thereof. Similar to many other drought stricken countries, South Africa requires water for the socio-economic growth of the country, yet is faced with the problem of maintaining the quality of its drinking water as well as protecting the dwindling supplies. In an attempt to prevent the deterioration of South African water supplies the treatment, purification and recycling of industrial and mining waste water has recently become of prime importance. Many industrial and mining waste waters contain heavy metals in toxic quantities. The conventional processes that have been used till recently to address this problem, are often expensive or contain chemical agents which compound the environmental problem. As an alternative biological methods of metal accumulation appear to offer an economic and efficient alternative to these methods. An advantage to the South African scenario is the commercial production of the yeast, S. cerevisiae as a readily inexpensive by-product from some fermentation industries, Yeast cells, and in particular S. cerevisiae have proven to be capable of accumulating heavy metals, and therefore exhibit potential application in the bioremediation of waste water. The aim of this project was twofold. The initial part of this work attempted to define the mechanisms of metal accumulation by the yeast cells and cellular components. The information obtained from these initial studies provided a data base required for the development of a bioremediation system. Initial contact with the metal ions occurs at the wall interface of the yeast cell. Metal accumulation appears to be a function of all the cell wall components. The isolated cell wall components are better metal chelators then the intact cell walls. An apparent affinity series of mannan > chitin> glucan > intact cell walls exists. However, these components differ in their affinities for metal ions. Storage of metal ions within the cell occurs predominantly in the vacuole. The present study concluded that metal accumulation by the vacuole could be related to size. Metal accumulation occurred in the order of Cu2+ > Co2+ > Cd2+ with a corresponding decrease in atomic radii of Cd2+ > C02+ > Cu2+. Vacuolar ion deposition occurs at an early stage during the internalization of metal ions within the yeast cells. At the onset of vacuolar saturation, depositions of metal ions as granules within the cytosol occurs. In the presence of heavy metal cations viable yeast cells can be shown to exhibit two types of cellular responses. Uptake of Cu2+ and Cd2+ causes the loss of intracellular physiological cations from within the yeast cell. In comparison, uptake of Co2+ into the cell does not have this effect. All three heavy metal cations initiate plasma cell membrane permeability, thus the Cu2+ and Cd2+ induced loss of the intracellular cations, occurs. ~ a result of ion-exchange mechanisms and not due to cation leakage brought about by membrane permeabilization. Uptake of heavy metals by viable yeasts appears to be generally non-selective though the amount of metals accumulated are largely affected by the ratio of ambient metal concentration to biomass quantity. In addition, the energy dependent nature of internalization necessitates the availability of an external energy source for metal uptake by viable yeast cells. For these reasons metal removal from industrial waste water was investigated using non-viable biomass. By immobilizing the yeast cells additional mechanical integrity and stability was conferred apon the biomass. The three types of biomass preparations developed in this study, viz. polyvinyl alcohol (PV A) Na-alginate, PV A Na-orthophosphate and alkali treated polyethylenimine (PEI):glutaraldehyde (GA) biomass pellets, all fulfilled the necessary physical requirements. However, the superior metal accumulating properties of the PEI:GA biomass determined its selection as a biosorbent for bioremediation purposes. Biosorption of heavy metals by PEI:GA biomass is of a competitive nature, with the amount of metal accumulated influenced by the availability of the metal ions. This availability is largely determined by the solution pH. At low pH values the affinity of the biomass for metals decreases, whilst enhanced metal biosorption occurs at higher pHs, ego pH 4.5 - 6.0. PEI:GA biomass pellets can be implemented -as a biosorbent for the bi9remediaiton of high concentration, low-volume metal containing industrial waste. Several options regarding the bioremediation system are available. Depending on the concentration of the metals in the effluent, the bioremediation process can either be used independently or as part of a biphasic remediation system for the treatment of waste water. Initial phase chemical modification may be required, whilst two types of biological systems can be implemented as 'part of the second phase. The PEI:GA biomass can either be contained within continuous-flow fixed bed tanks or continuous-flow stirred bioreactor tanks. Due to the simplicity of the process and the ease with which scale-up is facilitated, the second type of system shows greater application potential for the treatment of this type of industrial waste water than the fixed-bed systems.
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- Date Issued: 1997