The exploitation of methane from landfill
- Authors: Schütte, Renate
- Date: 1992
- Subjects: Methane , Waste products as fuel , Refuse as fuel , Sanitary landfills -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4530 , http://hdl.handle.net/10962/d1015949
- Description: A review of literature on the subject of methane exploitation from landfill is presented in conjunction with the results of experiments concerning landfill gas extraction at the Grahamstown Landfill Site. A description of the LFG extraction system and the utilisation of LFG at the Grahamstown Landfill Site is included. Data concerning LFG enhancement parameters, LFG compositions and flow rates, refuse composition, LFG modelling, LFG pumping trials and the economics of LFG extraction and utilisation are presented. The indication is that LFG can be economically extracted and utilised as a heating fuel in South Africa.
- Full Text:
- Date Issued: 1992
- Authors: Schütte, Renate
- Date: 1992
- Subjects: Methane , Waste products as fuel , Refuse as fuel , Sanitary landfills -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4530 , http://hdl.handle.net/10962/d1015949
- Description: A review of literature on the subject of methane exploitation from landfill is presented in conjunction with the results of experiments concerning landfill gas extraction at the Grahamstown Landfill Site. A description of the LFG extraction system and the utilisation of LFG at the Grahamstown Landfill Site is included. Data concerning LFG enhancement parameters, LFG compositions and flow rates, refuse composition, LFG modelling, LFG pumping trials and the economics of LFG extraction and utilisation are presented. The indication is that LFG can be economically extracted and utilised as a heating fuel in South Africa.
- Full Text:
- Date Issued: 1992
The exploration for and possible genesis of, some Archaean granite/gneiss-hosted gold deposits in the Pietersburg granite-greenstone terrane
- Linklater, Michael Anthony Leonard Flanders
- Authors: Linklater, Michael Anthony Leonard Flanders
- Date: 1992
- Subjects: Gold ores -- Geology -- South Africa , Gneiss , Granite
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4945 , http://hdl.handle.net/10962/d1005557 , Gold ores -- Geology -- South Africa , Gneiss , Granite
- Description: Abstract The gold mineralization event within Archaean granite-greenstone terranes occurred during the late Archaean, and followed the intrusion of syn- to late-tectonic granitic plutons into previously deformed greenstone belts. An Archaean granite/gneiss-hosted gold deposit, in terms of this project, is classified as having a gold-assay cutoff of 1g/metric ton over widths of at least several metres, or higher grades over narrower widths and/or verbal descriptions that indicate such values. Fluid inclusion studies and isotopic data identify two possible origins for the auriferous fluids; namely magmatic and metamorphic. The exploration target according to the magmatic model, is a late-Archaean, hydrothermally altered, mineralized and fractured granitic intrusion preferably with a granodioritic or quartz-dioritic composition. The exploration target according to the metamorphic replacement model is a granitic stock that has intruded a zone of crustal weakness such as a shear zone, active during the late Archaean. Alternatively, the granitic intrusion should be affected by regionally extensive late-Archaean shearing. It should be hydrothermally altered, deformed and mineralized. Five areas within the Pietersburg granite-greenstone terrane were selected for the 'Regional Area Selection' phase of exploration for Archaean granite/gneiss-hosted gold deposits; namely Roodepoort, Waterval, Ramagoep, Moletsie and Matlala. Roodepoort contains a known granodiorite-hosted gold deposit; the Knight's Pluton, and served as an orientation survey for this project. The use and interpretation of LANDSAT images formed an integral part of exploration techniques; to assess their usefulness in the exploration of Archaean granite/gneiss-hosted gold deposits. Area selection criteria for granite/gneiss-hosted gold mineralization at Roodepoort are the major ENE-trending shear zone, the NNW-trending lineament and hydrothermal alteration, shearing, quartz-stockworks and sulphide mineralization within the Knight's Pluton. The origin of the gold within the Knight's Pluton is uncertain; both magmatic and metamorphic models are possibilities. Ongoing exploration is in progress at Roodepoort. The only area selection criterion for granite/gneiss-hosted gold mineralization at Waterval is the sericitized, subcropping granites located within trenches. Gold mineralization is insignificant. No area selection criteria for Archaean granite/gneiss-hosted gold mineralization were located at Ramagoep, Matlala and Moletsie. No further exploration is recommended for all these areas. The MES image interpretations were successful in identifying lineaments, granitic outcrops, greenstones, vegetation and soil cover. The Clay-iron images adequately differentiated betweeen iron-rich and clay-bearing areas. However, not all clay-bearing areas were associated with hydrothermal alteratian; field checks were necessary to discriminate between weathered granites and hydrothermally altered granites. The Wallis images served to locally enhance the contrasts of the MES and Clay-iron images.
- Full Text:
- Date Issued: 1992
- Authors: Linklater, Michael Anthony Leonard Flanders
- Date: 1992
- Subjects: Gold ores -- Geology -- South Africa , Gneiss , Granite
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4945 , http://hdl.handle.net/10962/d1005557 , Gold ores -- Geology -- South Africa , Gneiss , Granite
- Description: Abstract The gold mineralization event within Archaean granite-greenstone terranes occurred during the late Archaean, and followed the intrusion of syn- to late-tectonic granitic plutons into previously deformed greenstone belts. An Archaean granite/gneiss-hosted gold deposit, in terms of this project, is classified as having a gold-assay cutoff of 1g/metric ton over widths of at least several metres, or higher grades over narrower widths and/or verbal descriptions that indicate such values. Fluid inclusion studies and isotopic data identify two possible origins for the auriferous fluids; namely magmatic and metamorphic. The exploration target according to the magmatic model, is a late-Archaean, hydrothermally altered, mineralized and fractured granitic intrusion preferably with a granodioritic or quartz-dioritic composition. The exploration target according to the metamorphic replacement model is a granitic stock that has intruded a zone of crustal weakness such as a shear zone, active during the late Archaean. Alternatively, the granitic intrusion should be affected by regionally extensive late-Archaean shearing. It should be hydrothermally altered, deformed and mineralized. Five areas within the Pietersburg granite-greenstone terrane were selected for the 'Regional Area Selection' phase of exploration for Archaean granite/gneiss-hosted gold deposits; namely Roodepoort, Waterval, Ramagoep, Moletsie and Matlala. Roodepoort contains a known granodiorite-hosted gold deposit; the Knight's Pluton, and served as an orientation survey for this project. The use and interpretation of LANDSAT images formed an integral part of exploration techniques; to assess their usefulness in the exploration of Archaean granite/gneiss-hosted gold deposits. Area selection criteria for granite/gneiss-hosted gold mineralization at Roodepoort are the major ENE-trending shear zone, the NNW-trending lineament and hydrothermal alteration, shearing, quartz-stockworks and sulphide mineralization within the Knight's Pluton. The origin of the gold within the Knight's Pluton is uncertain; both magmatic and metamorphic models are possibilities. Ongoing exploration is in progress at Roodepoort. The only area selection criterion for granite/gneiss-hosted gold mineralization at Waterval is the sericitized, subcropping granites located within trenches. Gold mineralization is insignificant. No area selection criteria for Archaean granite/gneiss-hosted gold mineralization were located at Ramagoep, Matlala and Moletsie. No further exploration is recommended for all these areas. The MES image interpretations were successful in identifying lineaments, granitic outcrops, greenstones, vegetation and soil cover. The Clay-iron images adequately differentiated betweeen iron-rich and clay-bearing areas. However, not all clay-bearing areas were associated with hydrothermal alteratian; field checks were necessary to discriminate between weathered granites and hydrothermally altered granites. The Wallis images served to locally enhance the contrasts of the MES and Clay-iron images.
- Full Text:
- Date Issued: 1992
The failure of the Coloured Persons' Representative Council and its constitutional repercussions, 1956-1985
- Authors: Saks, David
- Date: 1992
- Subjects: South African Labour Party , Federal Coloured People's Party -- South Africa , South Africa. Parliament , South Africa -- Politics and government -- 20th century , South Africa -- Race relations , Coloured Persons Representative Council of South Africa , Colored people (South Africa) -- Politics and government , Political parties -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2624 , http://hdl.handle.net/10962/d1015907
- Description: The thesis starts by providing a brief overview of South African ''Coloured" politics from the passing of Ordinance 50 in 1828 to the removal of the Cape Coloured people from the common voter's roll in 1956. It then goes on to discuss in detail the structures instituted by successive Nationalist Governments to serve as an alternative to parliamentary representation for the coloured people, the role of the various coloured political parties within such structures and the latter's gradual adaptation and development, culminating in the inauguration of the Tricameral Parliament in early 1985. The thesis is, on the one hand, a detailed record of coloured political activity following the loss of common roll voting rights in the Cape, focusing on specifically coloured political parties rather than on broader, non-ethnic resistance movements in which many coloured people took part during the same period. This covers the rise and rapid decline of a conservative grouping within the coloured community which sought to foster an exclusively coloured nationalism operating within the Government's policy of parallel development, and attempted to use the Coloured Persons' Representative Council as a means towards achieving the economic, social and political upliftment of the coloured people. It also deals with the important role of the Labour Party after 1966, showing how a moderate resistance movement carne to use the Council as a platform from which to confront the Government's apartheid policies and to render the institutions of parallel development unworkable through noncooperation and boycotting. The second important preoccupation of the thesis concerns the ambiguous and often contradictory attitudes towards the "coloured question" within the National Party itself. This ambivalence, it is argued, not only had much to do with the eventual failure of the Coloured Persons' Representative Council to become a viable substitute for Parliamentary representation acceptable to the majority of coloured people, but was also a primary cause of the National Party split in 1982. It shows too how the collapse of Grand Apartheid had its origins in the failure to incorporate the coloured population within its framework. The thesis is concerned primarily with coloured political developments. When relevant, however, the establishment and development of representative institutions for the Indian people is also dealt with, in so far as this overlaps with issues and events concerning the coloured Council. Finally, the five year period following the dissolution of the Coloured Persons' Representative Council in 1980 and the inauguration of the Tricameral Parliament in 1985 is briefly dealt with in a concluding chapter. This mainly concerns the gradual accommodation reached between the Government and the Labour Party when the latter eventually agreed, conditionally, to take part in the new constitution.
- Full Text:
- Date Issued: 1992
- Authors: Saks, David
- Date: 1992
- Subjects: South African Labour Party , Federal Coloured People's Party -- South Africa , South Africa. Parliament , South Africa -- Politics and government -- 20th century , South Africa -- Race relations , Coloured Persons Representative Council of South Africa , Colored people (South Africa) -- Politics and government , Political parties -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2624 , http://hdl.handle.net/10962/d1015907
- Description: The thesis starts by providing a brief overview of South African ''Coloured" politics from the passing of Ordinance 50 in 1828 to the removal of the Cape Coloured people from the common voter's roll in 1956. It then goes on to discuss in detail the structures instituted by successive Nationalist Governments to serve as an alternative to parliamentary representation for the coloured people, the role of the various coloured political parties within such structures and the latter's gradual adaptation and development, culminating in the inauguration of the Tricameral Parliament in early 1985. The thesis is, on the one hand, a detailed record of coloured political activity following the loss of common roll voting rights in the Cape, focusing on specifically coloured political parties rather than on broader, non-ethnic resistance movements in which many coloured people took part during the same period. This covers the rise and rapid decline of a conservative grouping within the coloured community which sought to foster an exclusively coloured nationalism operating within the Government's policy of parallel development, and attempted to use the Coloured Persons' Representative Council as a means towards achieving the economic, social and political upliftment of the coloured people. It also deals with the important role of the Labour Party after 1966, showing how a moderate resistance movement carne to use the Council as a platform from which to confront the Government's apartheid policies and to render the institutions of parallel development unworkable through noncooperation and boycotting. The second important preoccupation of the thesis concerns the ambiguous and often contradictory attitudes towards the "coloured question" within the National Party itself. This ambivalence, it is argued, not only had much to do with the eventual failure of the Coloured Persons' Representative Council to become a viable substitute for Parliamentary representation acceptable to the majority of coloured people, but was also a primary cause of the National Party split in 1982. It shows too how the collapse of Grand Apartheid had its origins in the failure to incorporate the coloured population within its framework. The thesis is concerned primarily with coloured political developments. When relevant, however, the establishment and development of representative institutions for the Indian people is also dealt with, in so far as this overlaps with issues and events concerning the coloured Council. Finally, the five year period following the dissolution of the Coloured Persons' Representative Council in 1980 and the inauguration of the Tricameral Parliament in 1985 is briefly dealt with in a concluding chapter. This mainly concerns the gradual accommodation reached between the Government and the Labour Party when the latter eventually agreed, conditionally, to take part in the new constitution.
- Full Text:
- Date Issued: 1992
The geology and evaluation of the "A"-reef at No.3 shaft, Western Holdings Mine, Welkom goldfield
- Blamey, Nigel John Frederick
- Authors: Blamey, Nigel John Frederick
- Date: 1992
- Subjects: Gold mines and mining -- South Africa -- Free State , Gold ores -- Geology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4957 , http://hdl.handle.net/10962/d1005569 , Gold mines and mining -- South Africa -- Free State , Gold ores -- Geology -- South Africa
- Description: The "A" -Reef occurs within the Aandenk Formation of the Central Rand Group, Witwatersrand Supergroup, in the Welkom Goldfield. It comprises the Witpan and Uitsig Reefs which are both oligomictic conglomerates, and are exploited for their gold content by Anglo American Corporation. The main Witpan channel complex is orientated in a NW-SE direction and occurs close to No.3 Shaft of Western Holdings Mine where it is currently being mined. The Witpan Reef varies in thickness from 7-220cm, with lateral facies changes controlling the thickness. Within the reef, gold is associated with degradation surfaces, carbonaceous material, increase in pebble sphericity, and channel edges. Two channel edges have yielded the best gold values on No.3 Shaft although the potential for further payable gold lies in the recognition of sieve conditions. The potential also exists for extensions of the "carbon"-bearing Uitsig channel currently being mined on President Steyn Mine. The palaeo-environment proposed for formation of the Witpan Reef is a braidplain that was partly reworked by a brief transgression. Ore evaluation using geostatistics was considered a valid technique as the dataset is sufficiently well structured. Semi-variograms in the channel and across-channel directions differ markedly. It was found that variograms of gold in cmg/t lacked sufficient structure for modelling, however, log semi-variogram modelling followed by simple log-kriging and back-transformation, proved to be the most successful method. Owing to the morphology and distribution of gold within the reef, a geologically based geostatistical valuation method is proposed. The potential for further exploration of "A" -Reef depends on a substantially higher gold price. In this event, exploration of Uitsig Reef to the southwest of the current mining area is recommended as well as a new exploration strategy for Witpan Reef.
- Full Text:
- Date Issued: 1992
- Authors: Blamey, Nigel John Frederick
- Date: 1992
- Subjects: Gold mines and mining -- South Africa -- Free State , Gold ores -- Geology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4957 , http://hdl.handle.net/10962/d1005569 , Gold mines and mining -- South Africa -- Free State , Gold ores -- Geology -- South Africa
- Description: The "A" -Reef occurs within the Aandenk Formation of the Central Rand Group, Witwatersrand Supergroup, in the Welkom Goldfield. It comprises the Witpan and Uitsig Reefs which are both oligomictic conglomerates, and are exploited for their gold content by Anglo American Corporation. The main Witpan channel complex is orientated in a NW-SE direction and occurs close to No.3 Shaft of Western Holdings Mine where it is currently being mined. The Witpan Reef varies in thickness from 7-220cm, with lateral facies changes controlling the thickness. Within the reef, gold is associated with degradation surfaces, carbonaceous material, increase in pebble sphericity, and channel edges. Two channel edges have yielded the best gold values on No.3 Shaft although the potential for further payable gold lies in the recognition of sieve conditions. The potential also exists for extensions of the "carbon"-bearing Uitsig channel currently being mined on President Steyn Mine. The palaeo-environment proposed for formation of the Witpan Reef is a braidplain that was partly reworked by a brief transgression. Ore evaluation using geostatistics was considered a valid technique as the dataset is sufficiently well structured. Semi-variograms in the channel and across-channel directions differ markedly. It was found that variograms of gold in cmg/t lacked sufficient structure for modelling, however, log semi-variogram modelling followed by simple log-kriging and back-transformation, proved to be the most successful method. Owing to the morphology and distribution of gold within the reef, a geologically based geostatistical valuation method is proposed. The potential for further exploration of "A" -Reef depends on a substantially higher gold price. In this event, exploration of Uitsig Reef to the southwest of the current mining area is recommended as well as a new exploration strategy for Witpan Reef.
- Full Text:
- Date Issued: 1992
The geology and geochemistry of the north-western portion of the Usushwana Complex, South-Eastern Transvaal
- Authors: Riganti, Angela
- Date: 1992
- Subjects: Geology -- South Africa -- Transvaal , Geochemistry -- South Africa -- Transvaal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4958 , http://hdl.handle.net/10962/d1005570 , Geology -- South Africa -- Transvaal , Geochemistry -- South Africa -- Transvaal
- Description: The 2.9 Ga old Usushwana Complex in the Piet Retief-Amsterdam area (south-eastern Transvaal) represents an exposed segment of a layered intrusion. It has the form of a dyke-like body elongated in a northwesterly direction, and extends to an estimated depth of 3000 -5500 m. Lithologically, the Complex consists of a cumulate succession of mafic rocks capped by granitoids and has intruded along the contact between the basement and the supracrustal sequences of the Kaapvaal Craton. Differentiation of an already contaminated gabbroic magma resulted in an ordered stratigraphic sequence comprising progressively more evolved lithotypes, with at least two imperfect cyclic units developed over a stratigraphic thickness of about 700 metres (Hlelo River Section). Meso- to orthocumulate textured gabbros and quartz gabbros grade upwards into magnetite- and apatite-bearing quartz gabbros, interlayered with discontinuous magnetitite horizons. The gabbros in turn grade into hornblende-rich, granophyric granodiorites. The differentiation process is regarded as having been considerably enhanced by the assimilation of acidic material, derived by partial melting of the felsic country rocks at the roof of the magma chamber. Recrystallisation of these rocks gave rise to the microgranites that locally overlie the granodiorites. Mineralogical, textural and geochemical features indicate a relatively advanced fractionation stage, suggesting that the exposed sequence of the Usushwana Complex in the study area represents the upper portion of the intrusion. No significant mineralised occurrences were identified. However, on the basis of similarities between the Usushwana Complex and other mafic layered intrusions which host significant ore deposits, it is suggested that economic concentrations of base metal(Cu-Ni) sulphides, PGE and chromitites are likely to be developed at lower stratigraphic levels.
- Full Text:
- Date Issued: 1992
- Authors: Riganti, Angela
- Date: 1992
- Subjects: Geology -- South Africa -- Transvaal , Geochemistry -- South Africa -- Transvaal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4958 , http://hdl.handle.net/10962/d1005570 , Geology -- South Africa -- Transvaal , Geochemistry -- South Africa -- Transvaal
- Description: The 2.9 Ga old Usushwana Complex in the Piet Retief-Amsterdam area (south-eastern Transvaal) represents an exposed segment of a layered intrusion. It has the form of a dyke-like body elongated in a northwesterly direction, and extends to an estimated depth of 3000 -5500 m. Lithologically, the Complex consists of a cumulate succession of mafic rocks capped by granitoids and has intruded along the contact between the basement and the supracrustal sequences of the Kaapvaal Craton. Differentiation of an already contaminated gabbroic magma resulted in an ordered stratigraphic sequence comprising progressively more evolved lithotypes, with at least two imperfect cyclic units developed over a stratigraphic thickness of about 700 metres (Hlelo River Section). Meso- to orthocumulate textured gabbros and quartz gabbros grade upwards into magnetite- and apatite-bearing quartz gabbros, interlayered with discontinuous magnetitite horizons. The gabbros in turn grade into hornblende-rich, granophyric granodiorites. The differentiation process is regarded as having been considerably enhanced by the assimilation of acidic material, derived by partial melting of the felsic country rocks at the roof of the magma chamber. Recrystallisation of these rocks gave rise to the microgranites that locally overlie the granodiorites. Mineralogical, textural and geochemical features indicate a relatively advanced fractionation stage, suggesting that the exposed sequence of the Usushwana Complex in the study area represents the upper portion of the intrusion. No significant mineralised occurrences were identified. However, on the basis of similarities between the Usushwana Complex and other mafic layered intrusions which host significant ore deposits, it is suggested that economic concentrations of base metal(Cu-Ni) sulphides, PGE and chromitites are likely to be developed at lower stratigraphic levels.
- Full Text:
- Date Issued: 1992
The growth characteristics of sparid otoliths
- Authors: Lang, Judy Brenda
- Date: 1992
- Subjects: Fishes -- Age determination , Otoliths , Sparidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5285 , http://hdl.handle.net/10962/d1005129 , Fishes -- Age determination , Otoliths , Sparidae
- Description: The periodicity of formation of growth increments in the otoliths of South African sparids was validated by the oxytetracycline labelling technique. Intramuscular injections of oxytetracycline at a dosage of 250mg/kg marked the otoliths of laboratory held juvenile sparids, while a dosage range of 50 - 100mg/kg oxytetracycline, injected intramuscularly, marked adult sparids in the field. Laboratory held, larval sparid otoliths were marked by immersion for 24hrs a solution of 100-150mg/l alizarin complexone. Both daily (microstructural) and annual (macrostructural) growth increments were identified in the otoliths. The micro incremental pattern of deposition in the sparid otoliths conformed to the general pattern of otolith structure. Sparid otoliths consisted of a central opaque nucleus composed of multiple primordia. surrounding this nucleus were daily increments which decreased in width as the distance from the nucleus increased. Both check rings and subdaily increments were visible throughout the otolith. Minor environmental changes did not affect micro incremental deposition. Narrow opaque and wide hyaline annual growth zones were identified in sectioned sparid otoliths. Scanning electron microscope analysis of the annual growth zones revealed that microincrements within the opaque zone were narrowly spaced with prominent discontinuous phases. This resulted in the greater optical density and higher protein content of the zone. The hyaline zone was composed of widely spaced daily increments with prominent incremental phases accounting for the translucent nature of this zone. Opaque zone formation in the otoliths of many South African sparids was found to occur primarily during periods of reproductive activity and was shown to be indicative of slow otolith growth. The hyaline zone was formed after the spawning season, representative of fast otolith growth. The results of this study have resolved much of the controversy surrounding the rate of growth and time of formation of the opaque and hyaline growth zones in South African sparid otoliths.
- Full Text:
- Date Issued: 1992
- Authors: Lang, Judy Brenda
- Date: 1992
- Subjects: Fishes -- Age determination , Otoliths , Sparidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5285 , http://hdl.handle.net/10962/d1005129 , Fishes -- Age determination , Otoliths , Sparidae
- Description: The periodicity of formation of growth increments in the otoliths of South African sparids was validated by the oxytetracycline labelling technique. Intramuscular injections of oxytetracycline at a dosage of 250mg/kg marked the otoliths of laboratory held juvenile sparids, while a dosage range of 50 - 100mg/kg oxytetracycline, injected intramuscularly, marked adult sparids in the field. Laboratory held, larval sparid otoliths were marked by immersion for 24hrs a solution of 100-150mg/l alizarin complexone. Both daily (microstructural) and annual (macrostructural) growth increments were identified in the otoliths. The micro incremental pattern of deposition in the sparid otoliths conformed to the general pattern of otolith structure. Sparid otoliths consisted of a central opaque nucleus composed of multiple primordia. surrounding this nucleus were daily increments which decreased in width as the distance from the nucleus increased. Both check rings and subdaily increments were visible throughout the otolith. Minor environmental changes did not affect micro incremental deposition. Narrow opaque and wide hyaline annual growth zones were identified in sectioned sparid otoliths. Scanning electron microscope analysis of the annual growth zones revealed that microincrements within the opaque zone were narrowly spaced with prominent discontinuous phases. This resulted in the greater optical density and higher protein content of the zone. The hyaline zone was composed of widely spaced daily increments with prominent incremental phases accounting for the translucent nature of this zone. Opaque zone formation in the otoliths of many South African sparids was found to occur primarily during periods of reproductive activity and was shown to be indicative of slow otolith growth. The hyaline zone was formed after the spawning season, representative of fast otolith growth. The results of this study have resolved much of the controversy surrounding the rate of growth and time of formation of the opaque and hyaline growth zones in South African sparid otoliths.
- Full Text:
- Date Issued: 1992
The in-service development of primary school teachers in the use of computers in education with special reference to computer assisted learning: a case study
- Authors: Murray, John Charles
- Date: 1992
- Subjects: Education, Elementary -- South Africa -- Data processing Computer-assisted instruction Teachers -- In-service training -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1572 , http://hdl.handle.net/10962/d1003454
- Description: Many white primary schools in South Africa have acquired computers which are being used in various ways. In my experience few members of staff are confident enough to use the computers in the school for educational purposes. Those who have been using them, generally have been doing computer literacy. The teachers in our school expressed the view that they would like to be able to use the computer, but that they lack the necessary skills and therefore would welcome some form of training. In my opinion computers should form an integral part of a child's learning environment. It has, for some time formed a part of his social environment, either in the home or in the workplace. For computers to be used effectively in the classroom, it follows that the teachers need to be trained to use them. In an attempt to overcome this problem, I designed and presented an in-service course, which used selected computer assisted learning (CAL) programs with teachers. These teachers then used these programs with the pupils in their class and evaluated the pupils' reactions to the innovation. As a result of the observations and the feedback provided by the sample of teachers, it is suggested that this might be a possible approach to in-service training for other schools. With adaptation it should be possible to follow this approach in any school which has a computer and someone on the staff who is willing to take the initiative to implement such an innovation.
- Full Text:
- Date Issued: 1992
- Authors: Murray, John Charles
- Date: 1992
- Subjects: Education, Elementary -- South Africa -- Data processing Computer-assisted instruction Teachers -- In-service training -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1572 , http://hdl.handle.net/10962/d1003454
- Description: Many white primary schools in South Africa have acquired computers which are being used in various ways. In my experience few members of staff are confident enough to use the computers in the school for educational purposes. Those who have been using them, generally have been doing computer literacy. The teachers in our school expressed the view that they would like to be able to use the computer, but that they lack the necessary skills and therefore would welcome some form of training. In my opinion computers should form an integral part of a child's learning environment. It has, for some time formed a part of his social environment, either in the home or in the workplace. For computers to be used effectively in the classroom, it follows that the teachers need to be trained to use them. In an attempt to overcome this problem, I designed and presented an in-service course, which used selected computer assisted learning (CAL) programs with teachers. These teachers then used these programs with the pupils in their class and evaluated the pupils' reactions to the innovation. As a result of the observations and the feedback provided by the sample of teachers, it is suggested that this might be a possible approach to in-service training for other schools. With adaptation it should be possible to follow this approach in any school which has a computer and someone on the staff who is willing to take the initiative to implement such an innovation.
- Full Text:
- Date Issued: 1992
The influence of children on decision-makers in their homes : a case study in environmental education
- Authors: Kruger, Jacqueline
- Date: 1992
- Subjects: Environmental education -- South Africa , Parent and child -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1574 , http://hdl.handle.net/10962/d1003456
- Description: This study explores the possible influence of twenty children on their 'parents', with a view to better understanding the potential 'multiplier effect' of children regarding environmental responsibility. The criteria employed to study the potential influence included certain of the environmental activities learnt by the children during an Environmental Education programme. The programme was undertaken by the researcher with a Std 4 class from Ryneveld Primêreskool in Graaff-Reinet. An action research approach was adopted and results were analysed qualitatively. Due to the short duration and exploratory nature of the project, these results should be viewed as tentative. Proposals are made for increasing the impact of Environmental Education programmes in peri-urban township communities, and recommendations are put forward to help facilitate related studies in the future.
- Full Text:
- Date Issued: 1992
- Authors: Kruger, Jacqueline
- Date: 1992
- Subjects: Environmental education -- South Africa , Parent and child -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1574 , http://hdl.handle.net/10962/d1003456
- Description: This study explores the possible influence of twenty children on their 'parents', with a view to better understanding the potential 'multiplier effect' of children regarding environmental responsibility. The criteria employed to study the potential influence included certain of the environmental activities learnt by the children during an Environmental Education programme. The programme was undertaken by the researcher with a Std 4 class from Ryneveld Primêreskool in Graaff-Reinet. An action research approach was adopted and results were analysed qualitatively. Due to the short duration and exploratory nature of the project, these results should be viewed as tentative. Proposals are made for increasing the impact of Environmental Education programmes in peri-urban township communities, and recommendations are put forward to help facilitate related studies in the future.
- Full Text:
- Date Issued: 1992
The interactive effects of light, temperature and CO₂/O₂ ratios in photosynthesis of Coix lachryma-jobi L
- Authors: Mjwara, Jabulani Michael
- Date: 1992
- Subjects: Coix , Plants -- Effect of light on , Plants -- Effect of oxygen on , Plants -- Effect of carbon dioxide on , Photosynthesis , Plants -- Effect of temperature on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4216 , http://hdl.handle.net/10962/d1003785
- Description: A portable infra red gas analyzer was used to investigate the interactive effects of light, temperature, and CO,jO, ratios under controlled environmental conditions in an attempt to model gas exchange characteristics of Coix Iachryma-jobi L. Plotting light response curves as a function of temperature (20, 25 30 and 35°C) revealed no sign of light saturation even at a photosynthetic photon flux density (PPFD) close to 2000 !Lmol m-' sol. High net assimilation rates (A) of approximately 24 !Lmol CO, m"s'! were realized at 30-35°C. Assimilation (A) versus internal CO, partial pressure (C,) curves showed a steep rise with increase in C, but saturated at approximately 150 (JLII-!) and all the results, either in the absence or presence of 0" showed a similar response under all temperature regimes. C. Iachryma-jobi exhibited low CO, compensation points cr ) between 0 and 10 JLlI-! under similar experimental temperatures and either at 0 or 21%0,. The slopes of double reciprocal plots of llA versus llCi, were nearly identical and crossed the yintercept at almost identical points under all 0, concentrations. These data indicate first; that there was no apparent 0, inhibition and second; indicated that the apparent inhIbitor constant (K,) for 0, at the site of carboxylation did not change with increase in [OJ from 0 to 21% oxygen. These observations were further confirmed by results obtained from the analysis of apparent carboxylation efficiency (CE, as defined as the slope of response of A to increasing CO,), as no inhibition of A with increase of [OJ occurred. These characteristics were consistent with typical features of C,photosynthesis. The absence of 0, inhibition and low r values indicated that an efficient CO, concentrating mechanism which eliminates photorespiration exists in C. Iachryma-jobi. At the light microscope level, leaf anatomy exhibited typical C, structure viz. bundle sheath with large chloroplasts and this sheath is further surrounded by a radiate Kranz mesophyU cells. Furthermore the anatomical features suggested that C. wchryma-jobi was an NADP-ME species. Stomatal conductance (g,) to assimilation (g,/A) indicated an increase in A with decrease in g" an essential feature of improving water use efficiency (WUE), but one which drastically reduces CO, diffusion rate. The physical lintitation (stomatal lintitation, t) to CO, diffusion under various [0,] and temperatures, but constant PPFD, did not exhibit statistically significant change in t values at either 0 or 21% a, within each temperature regime, however there was a marked decrease in t as the plant approached its optimum photosynthetic temperature.
- Full Text:
- Date Issued: 1992
- Authors: Mjwara, Jabulani Michael
- Date: 1992
- Subjects: Coix , Plants -- Effect of light on , Plants -- Effect of oxygen on , Plants -- Effect of carbon dioxide on , Photosynthesis , Plants -- Effect of temperature on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4216 , http://hdl.handle.net/10962/d1003785
- Description: A portable infra red gas analyzer was used to investigate the interactive effects of light, temperature, and CO,jO, ratios under controlled environmental conditions in an attempt to model gas exchange characteristics of Coix Iachryma-jobi L. Plotting light response curves as a function of temperature (20, 25 30 and 35°C) revealed no sign of light saturation even at a photosynthetic photon flux density (PPFD) close to 2000 !Lmol m-' sol. High net assimilation rates (A) of approximately 24 !Lmol CO, m"s'! were realized at 30-35°C. Assimilation (A) versus internal CO, partial pressure (C,) curves showed a steep rise with increase in C, but saturated at approximately 150 (JLII-!) and all the results, either in the absence or presence of 0" showed a similar response under all temperature regimes. C. Iachryma-jobi exhibited low CO, compensation points cr ) between 0 and 10 JLlI-! under similar experimental temperatures and either at 0 or 21%0,. The slopes of double reciprocal plots of llA versus llCi, were nearly identical and crossed the yintercept at almost identical points under all 0, concentrations. These data indicate first; that there was no apparent 0, inhibition and second; indicated that the apparent inhIbitor constant (K,) for 0, at the site of carboxylation did not change with increase in [OJ from 0 to 21% oxygen. These observations were further confirmed by results obtained from the analysis of apparent carboxylation efficiency (CE, as defined as the slope of response of A to increasing CO,), as no inhibition of A with increase of [OJ occurred. These characteristics were consistent with typical features of C,photosynthesis. The absence of 0, inhibition and low r values indicated that an efficient CO, concentrating mechanism which eliminates photorespiration exists in C. Iachryma-jobi. At the light microscope level, leaf anatomy exhibited typical C, structure viz. bundle sheath with large chloroplasts and this sheath is further surrounded by a radiate Kranz mesophyU cells. Furthermore the anatomical features suggested that C. wchryma-jobi was an NADP-ME species. Stomatal conductance (g,) to assimilation (g,/A) indicated an increase in A with decrease in g" an essential feature of improving water use efficiency (WUE), but one which drastically reduces CO, diffusion rate. The physical lintitation (stomatal lintitation, t) to CO, diffusion under various [0,] and temperatures, but constant PPFD, did not exhibit statistically significant change in t values at either 0 or 21% a, within each temperature regime, however there was a marked decrease in t as the plant approached its optimum photosynthetic temperature.
- Full Text:
- Date Issued: 1992
The psychological sequelae of involvement in combat: a preliminary investigation
- Authors: Hodgson, Shane Ralph Colin
- Date: 1992
- Subjects: War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:2993 , http://hdl.handle.net/10962/d1002502 , War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Description: The psychological sequelae of being involved in combat are only recently coming to be understood. Most of the available data are from research conducted on help-seeking Vietnam veterans in the United States, and very little work has been done in South Africa. There does not as yet appear to be any instrument designed specifically to detect combat-related psychopathologies amongst soldiers who are still in active service, either in the USA or in South Africa. Combat involvement has been shown to lead to a high incidence of combat stress reaction. This in turn has shown that it can predispose sufferers to the development of a Post-traumatic Stress Disorder. It is thus expected that there would be significantly higher incidences of reported symptoms of stress disorders amongst soldiers exposed to high levels of combat as compared with a similar group of soldiers who had no combat involvement. This study used a self-reporting questionnaire, developed in the USA but adapted for use in South Africa, to allow the soldiers in the study to rate the severity of various symptoms derived from the DSM-III criteria for Post-traumatic Stress Disorder. A Beck Depression Inventory was also administered to eliminate any persons who nay have been exhibiting symptoms of depression, as this would have confounded the results. Both questionnaires were administered to serving members of the Permanent Force of the South African Defence Force, with one group being members of various high-combat units based in what was then South West Africa, and the other group being non-combat or Headquarters elements. As a precondition of the study, absolute confidentiality of the respondents and their units was maintained. The study found the expected higher scores in the high-combat group, and also showed that the Keane questionnaire has a good coefficient alpha in South Africa. The study closes with several recommendations for further research, especially in the light of the new PTSD criteria in the DSM-IIIR.
- Full Text:
- Date Issued: 1992
- Authors: Hodgson, Shane Ralph Colin
- Date: 1992
- Subjects: War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:2993 , http://hdl.handle.net/10962/d1002502 , War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Description: The psychological sequelae of being involved in combat are only recently coming to be understood. Most of the available data are from research conducted on help-seeking Vietnam veterans in the United States, and very little work has been done in South Africa. There does not as yet appear to be any instrument designed specifically to detect combat-related psychopathologies amongst soldiers who are still in active service, either in the USA or in South Africa. Combat involvement has been shown to lead to a high incidence of combat stress reaction. This in turn has shown that it can predispose sufferers to the development of a Post-traumatic Stress Disorder. It is thus expected that there would be significantly higher incidences of reported symptoms of stress disorders amongst soldiers exposed to high levels of combat as compared with a similar group of soldiers who had no combat involvement. This study used a self-reporting questionnaire, developed in the USA but adapted for use in South Africa, to allow the soldiers in the study to rate the severity of various symptoms derived from the DSM-III criteria for Post-traumatic Stress Disorder. A Beck Depression Inventory was also administered to eliminate any persons who nay have been exhibiting symptoms of depression, as this would have confounded the results. Both questionnaires were administered to serving members of the Permanent Force of the South African Defence Force, with one group being members of various high-combat units based in what was then South West Africa, and the other group being non-combat or Headquarters elements. As a precondition of the study, absolute confidentiality of the respondents and their units was maintained. The study found the expected higher scores in the high-combat group, and also showed that the Keane questionnaire has a good coefficient alpha in South Africa. The study closes with several recommendations for further research, especially in the light of the new PTSD criteria in the DSM-IIIR.
- Full Text:
- Date Issued: 1992
The relationship of general retention ability to new South African group test non-verbal/verbal IQ discrepancies and their academic correlates
- Authors: Watson, Peter James
- Date: 1992
- Subjects: Intellect Intelligence tests -- South Africa Academic achievement -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1725 , http://hdl.handle.net/10962/d1003608
- Description: Both experimental research (Robbertse,1952)and clinical observation (Kruger, 1972; van der Merwe,1978) have indicated that pupils with a Verbal IQ score 10 or more points lower than their non-Verbal IQ (termed a 'Type 1' discrepancy in the present research) on the New South African Group Test (NSAGT) show poorer academic achievement than their peers of similar ability. The present research investigates the relationship of general retention ability, as defined by Hakstian and Cattell (1978), to Type 1 discrepancies as well as to their academic correlates. One hundred and thirty-nine standard seven English-speaking boys were tested on the NSAGT and the Junior Aptitude Test (JAT) (of which tests 8 and 9 give an indication of general retention ability) and divided into a group with Type 1 discrepancies and two control groups. All three groups were matched on full-scale IQ. Comparison of these three groups, using the analysis of variance technique, showed that there was no significant difference between them in level of general retention ability or in academic performance (measured by average percentage in the final standard seven examination). While no significant difference was found between the three groups regarding the relationship of general retention ability to academic performance, in the Type 1 discrepancy group the relationship of rote memory (JAT test 8) to academic performance differed markedly from that of associative memory (JAT test 9) to academic performance. In the Type 1 discrepancy group rote memory was highly associated with academic performance, possibly indicating a compensatory strategy for the lower Verbal ability in this group, enabling it to achieve academically on par with the control groups, contrary to what would be expected on the basis of Robbertse's (1962) findings. In terms of Jensen's (1982) Level 1/Level 11 theory of intelligence, it appears from the present research that rote memory ability (JAT test 8) varies between being a Level 11 ability (in the Type 1 discrepancy group) to acting as a Level 1 ability in the two control groups. The present research questions Verwey and Wolmarans's (1980) description of both JAT tests 8 and 9 as simple measures of retention Test 9, in particular, appears to function consistently as a Level 11 ability.
- Full Text:
- Date Issued: 1992
- Authors: Watson, Peter James
- Date: 1992
- Subjects: Intellect Intelligence tests -- South Africa Academic achievement -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1725 , http://hdl.handle.net/10962/d1003608
- Description: Both experimental research (Robbertse,1952)and clinical observation (Kruger, 1972; van der Merwe,1978) have indicated that pupils with a Verbal IQ score 10 or more points lower than their non-Verbal IQ (termed a 'Type 1' discrepancy in the present research) on the New South African Group Test (NSAGT) show poorer academic achievement than their peers of similar ability. The present research investigates the relationship of general retention ability, as defined by Hakstian and Cattell (1978), to Type 1 discrepancies as well as to their academic correlates. One hundred and thirty-nine standard seven English-speaking boys were tested on the NSAGT and the Junior Aptitude Test (JAT) (of which tests 8 and 9 give an indication of general retention ability) and divided into a group with Type 1 discrepancies and two control groups. All three groups were matched on full-scale IQ. Comparison of these three groups, using the analysis of variance technique, showed that there was no significant difference between them in level of general retention ability or in academic performance (measured by average percentage in the final standard seven examination). While no significant difference was found between the three groups regarding the relationship of general retention ability to academic performance, in the Type 1 discrepancy group the relationship of rote memory (JAT test 8) to academic performance differed markedly from that of associative memory (JAT test 9) to academic performance. In the Type 1 discrepancy group rote memory was highly associated with academic performance, possibly indicating a compensatory strategy for the lower Verbal ability in this group, enabling it to achieve academically on par with the control groups, contrary to what would be expected on the basis of Robbertse's (1962) findings. In terms of Jensen's (1982) Level 1/Level 11 theory of intelligence, it appears from the present research that rote memory ability (JAT test 8) varies between being a Level 11 ability (in the Type 1 discrepancy group) to acting as a Level 1 ability in the two control groups. The present research questions Verwey and Wolmarans's (1980) description of both JAT tests 8 and 9 as simple measures of retention Test 9, in particular, appears to function consistently as a Level 11 ability.
- Full Text:
- Date Issued: 1992
The role of the teachers' centre in the professional development and in-service training of teachers with specific reference to the East London Teachers' Centre
- Authors: Badenhorst, John Henry
- Date: 1992
- Subjects: Teachers -- In-service training -- South Africa , Education -- South Africa -- East London , Professional education -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1755 , http://hdl.handle.net/10962/d1003639 , Teachers -- In-service training -- South Africa , Education -- South Africa -- East London , Professional education -- South Africa , Educational change -- South Africa
- Description: Teachers' Centres are one of the means whereby teachers needs for in-service education and training (Inset) can be met. The professional basis of Teachers' Centres as providers of in-service education and training derives from the need of teachers to develop professionally throughout their careers. Aspects which need to be considered are the need for professional growth and the professional nature of teaching. The effective provision of in-service training requires a knowledge of effective in-service training practise and the barriers that could be encountered in presenting it. Central to any Inset for teachers would be the teachers' needs for such activity. Following on a general statement of teachers needs for Inset the role of the Teachers' Centre in meeting these needs will be examined. Teachers' Centres have specific advantages in meeting certain areas of need for Inset by teachers. A knowledge of the professional activities of teachers activity and methods of establishing the needs for Inset of teachers should promote the effective provision of these programmes. The teacher as an adult learner is important to effective Teachers' Centre operation and the nature of adult learning and variables which affect it will determine the Teachers' Centre reaction in providing Inset. Subject study group activity is very important in Teachers' Centres in the Cape Province and the principles involved in their operation together with practical considerations regarding their operation are important in the provision of Inset. The practical application of theory is illustrated by examples from the East London Teachers' Centre with an emphasis on organisation and the creation of a climate within the Centre for the existence of study groups. The presentation methods used in these study group activities are important and will vary according to the needs of the study group. The selection of methods together with the organisation of presentations and practical methods used in presentation will have an important effect on how they operate. Teachers' Centres have a role to play in promoting change and innovation in schools. The theories of promoting innovation and the roles of the change agent are important. Practical examples from the East London Teachers' Centre are provided. This research, thus, provides a theoretical study of the role of Teachers' Centres in meeting some of the inset needs of teachers as well as practical examples of such activities.
- Full Text:
- Date Issued: 1992
- Authors: Badenhorst, John Henry
- Date: 1992
- Subjects: Teachers -- In-service training -- South Africa , Education -- South Africa -- East London , Professional education -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1755 , http://hdl.handle.net/10962/d1003639 , Teachers -- In-service training -- South Africa , Education -- South Africa -- East London , Professional education -- South Africa , Educational change -- South Africa
- Description: Teachers' Centres are one of the means whereby teachers needs for in-service education and training (Inset) can be met. The professional basis of Teachers' Centres as providers of in-service education and training derives from the need of teachers to develop professionally throughout their careers. Aspects which need to be considered are the need for professional growth and the professional nature of teaching. The effective provision of in-service training requires a knowledge of effective in-service training practise and the barriers that could be encountered in presenting it. Central to any Inset for teachers would be the teachers' needs for such activity. Following on a general statement of teachers needs for Inset the role of the Teachers' Centre in meeting these needs will be examined. Teachers' Centres have specific advantages in meeting certain areas of need for Inset by teachers. A knowledge of the professional activities of teachers activity and methods of establishing the needs for Inset of teachers should promote the effective provision of these programmes. The teacher as an adult learner is important to effective Teachers' Centre operation and the nature of adult learning and variables which affect it will determine the Teachers' Centre reaction in providing Inset. Subject study group activity is very important in Teachers' Centres in the Cape Province and the principles involved in their operation together with practical considerations regarding their operation are important in the provision of Inset. The practical application of theory is illustrated by examples from the East London Teachers' Centre with an emphasis on organisation and the creation of a climate within the Centre for the existence of study groups. The presentation methods used in these study group activities are important and will vary according to the needs of the study group. The selection of methods together with the organisation of presentations and practical methods used in presentation will have an important effect on how they operate. Teachers' Centres have a role to play in promoting change and innovation in schools. The theories of promoting innovation and the roles of the change agent are important. Practical examples from the East London Teachers' Centre are provided. This research, thus, provides a theoretical study of the role of Teachers' Centres in meeting some of the inset needs of teachers as well as practical examples of such activities.
- Full Text:
- Date Issued: 1992
The status of the American bollworm, Heliothis armigera (Hubner) (Lepidoptera : Noctuidae), on sunflower in the central Transvaal
- Authors: Von Maltitz, Emil Friedrich
- Date: 1992
- Subjects: Helicoverpa armigera , Noctuidae -- South Africa -- Transvaal , Noctuidae , Sunflowers -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5773 , http://hdl.handle.net/10962/d1005461 , Helicoverpa armigera , Noctuidae -- South Africa -- Transvaal , Noctuidae , Sunflowers -- Diseases and pests
- Description: Sunflower production in South Africa has increased four fold since the 1970's. This study was done to elucidate the pest status of Heliothis armigera (Hiibner) on sunflower. Field studies were undertaken at Warmbaths, Brits and Delmas during the summer seasons of 1988/89 to 1990/91. The infestations at the latter two areas were negligible throughout the study period and their statistics have not been included in this thesis. Plant development and oviposition by natural H. armigera populations were found to be correlated as, regardless of planting date, oviposition started at six to seven weeks after planting; when the flowering stage began. A peak in egg numbers was reached by the tenth week with an average for the three seasons at two eggs per plant. The eggs were laid singly on the bracts and bases of the flower buds. A peak in larval numbers was reached at the thirteenth week after planting with the average for the three seasons of 0,4 larvae per plant. The preferred feeding sites were on, between and under the bracts from where the larvae burrow into the pithy tissue of the receptacle. Only six percent of the larvae were found feeding directly on the achenes. Eggs and larvae collected were reared to determine the degree of parasitism. Overall, 19% of the eggs were parasitised; 18% by Telenomus ullyetti Nixon (Scelionidae) and one percent by Trichogrammatoidea lutea (Trichogrammatidae). Larval parasitism at Warmbaths was 23% in 1988/89, 27% in 1989/90 and 34% in 1990/91. Of the parasitised larvae, 44% succumbed to Palexorista prob. laxa (Tachinidae). The remainder were unidentified Braconidae and Ichneumonidae. Predators, such as chrysopids, were observed during the study but their effect on egg and larvae numbers was not studied in detail. A polyhedral virus occurred late in the seasons and caused mortality of the larvae. The low numbers of H. armigera on sunflower, the slight damage to the crop and the reasonably high rate of parasitism, all seem to indicate that H. armigera is not an economica1ly important pest of sunflower and that additional control methods are not justified.
- Full Text:
- Date Issued: 1992
- Authors: Von Maltitz, Emil Friedrich
- Date: 1992
- Subjects: Helicoverpa armigera , Noctuidae -- South Africa -- Transvaal , Noctuidae , Sunflowers -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5773 , http://hdl.handle.net/10962/d1005461 , Helicoverpa armigera , Noctuidae -- South Africa -- Transvaal , Noctuidae , Sunflowers -- Diseases and pests
- Description: Sunflower production in South Africa has increased four fold since the 1970's. This study was done to elucidate the pest status of Heliothis armigera (Hiibner) on sunflower. Field studies were undertaken at Warmbaths, Brits and Delmas during the summer seasons of 1988/89 to 1990/91. The infestations at the latter two areas were negligible throughout the study period and their statistics have not been included in this thesis. Plant development and oviposition by natural H. armigera populations were found to be correlated as, regardless of planting date, oviposition started at six to seven weeks after planting; when the flowering stage began. A peak in egg numbers was reached by the tenth week with an average for the three seasons at two eggs per plant. The eggs were laid singly on the bracts and bases of the flower buds. A peak in larval numbers was reached at the thirteenth week after planting with the average for the three seasons of 0,4 larvae per plant. The preferred feeding sites were on, between and under the bracts from where the larvae burrow into the pithy tissue of the receptacle. Only six percent of the larvae were found feeding directly on the achenes. Eggs and larvae collected were reared to determine the degree of parasitism. Overall, 19% of the eggs were parasitised; 18% by Telenomus ullyetti Nixon (Scelionidae) and one percent by Trichogrammatoidea lutea (Trichogrammatidae). Larval parasitism at Warmbaths was 23% in 1988/89, 27% in 1989/90 and 34% in 1990/91. Of the parasitised larvae, 44% succumbed to Palexorista prob. laxa (Tachinidae). The remainder were unidentified Braconidae and Ichneumonidae. Predators, such as chrysopids, were observed during the study but their effect on egg and larvae numbers was not studied in detail. A polyhedral virus occurred late in the seasons and caused mortality of the larvae. The low numbers of H. armigera on sunflower, the slight damage to the crop and the reasonably high rate of parasitism, all seem to indicate that H. armigera is not an economica1ly important pest of sunflower and that additional control methods are not justified.
- Full Text:
- Date Issued: 1992
The surface geology of the Lavino Chrome Mine of the farm Grootboom 336KT, eastern Transvaal
- Authors: Tinney, Christopher Bruce
- Date: 1992
- Subjects: Chromium ores -- Geology -- South Africa -- Mpumalanga
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5067 , http://hdl.handle.net/10962/d1013404
- Description: A mapping project of the surface geology of the Lavino chrome mine and its surroundings was initiated in order to establish the surface geological relationships in the area. In so doing the chromitite layer presently being mined has been identified and potential exploration targets in the area have been outlined. The Lavino Chrome mine field area is situated within the eastern lobe of the Bushveld Igneous Complex. The area is bounded by in the north by the Steelpoort Lineament, in the west by the Dwars River fault and in the east by the contact with the Transvaal Sequence floor rocks. Layered igneous rocks (pyroxenites, norites and anorthosites) of the Rustenburg Layered Suite dominate the geological landscape at the Lavino mine. The fact that outcropping igneous rocks of the Critical Zone abut directly against the quartzite floor rocks on the mine property makes this area unique in the Bushveld Complex. The hills in the field area are capped by mafic/ultramafic iron-rich sheet - like bodies. Extensive strike-slip faulting is seen in outcrop in the area to the north/northwest of present mining operations. On the basis of field relationships, the main chromitite layer presently being mined at Lavino is identified as the Middle Group chromitite layer MG 1. Three other prominent chromitite layers stratigraphically associated with MG 1 are identified as the Middle Group chromitites MG 2, MG 3 and MG 4. Several other less prominent outcropping chromitite layers are tentatively identified as those belonging to the Lower and Upper group of chromitites. The disconformable nature of the contact between the layered igneous rocks and the Transvaal Sequence floor rocks has resulted in the development of a wedge of undifferentiated pyroxenites in the north of the field area. The economically important LG 6 chromitite layer may be developed in subcrop within this wedge.
- Full Text:
- Date Issued: 1992
- Authors: Tinney, Christopher Bruce
- Date: 1992
- Subjects: Chromium ores -- Geology -- South Africa -- Mpumalanga
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5067 , http://hdl.handle.net/10962/d1013404
- Description: A mapping project of the surface geology of the Lavino chrome mine and its surroundings was initiated in order to establish the surface geological relationships in the area. In so doing the chromitite layer presently being mined has been identified and potential exploration targets in the area have been outlined. The Lavino Chrome mine field area is situated within the eastern lobe of the Bushveld Igneous Complex. The area is bounded by in the north by the Steelpoort Lineament, in the west by the Dwars River fault and in the east by the contact with the Transvaal Sequence floor rocks. Layered igneous rocks (pyroxenites, norites and anorthosites) of the Rustenburg Layered Suite dominate the geological landscape at the Lavino mine. The fact that outcropping igneous rocks of the Critical Zone abut directly against the quartzite floor rocks on the mine property makes this area unique in the Bushveld Complex. The hills in the field area are capped by mafic/ultramafic iron-rich sheet - like bodies. Extensive strike-slip faulting is seen in outcrop in the area to the north/northwest of present mining operations. On the basis of field relationships, the main chromitite layer presently being mined at Lavino is identified as the Middle Group chromitite layer MG 1. Three other prominent chromitite layers stratigraphically associated with MG 1 are identified as the Middle Group chromitites MG 2, MG 3 and MG 4. Several other less prominent outcropping chromitite layers are tentatively identified as those belonging to the Lower and Upper group of chromitites. The disconformable nature of the contact between the layered igneous rocks and the Transvaal Sequence floor rocks has resulted in the development of a wedge of undifferentiated pyroxenites in the north of the field area. The economically important LG 6 chromitite layer may be developed in subcrop within this wedge.
- Full Text:
- Date Issued: 1992
The utilization of tilting-filter photometry in airglow and auroral research
- Authors: Dore, Ian Stuart
- Date: 1992
- Subjects: Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5494 , http://hdl.handle.net/10962/d1005280 , Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Description: This thesis describes the application of tilting-filter photometry to the study of the airglow and aurora. Previous South African photometric research is reviewed. Optical instrumentation and techniques used in airglow and auroral research are reviewed. The transmission characteristics of narrowband interference filters are discussed. The analogue meridian-scanning tilting-filter photometry system used at Sanae, Antarctica is described. Shortcomings of this system have been identified, and modifications have been made to improve its spatial and temporal resolution. Details are given of the computer-controlled digital photometry system which replaced the analogue system. Equations are derived for the conversion of raw photometric data (analogue chart deflections or digital photon counts) to absolute emission intensities. The accuracy of the intensities obtained depends on the absolute calibration of the photometer, the transmission characteristics of the filter used to isolate the spectral feature of interest, and the effects of atmospheric extinction and scattering. The influence of these factors on observed emission intensities is discussed. Various models used to determine atmospheric correction factors are reviewed. It is shown that atmospheric correction factors can have a significant effect on both emission intensities and intensity ratios. The procedure used to determine the transmission characteristics of interference filters is described, as is the procedure used to cross-calibrate secondary light sources. The transmission characteristics of the filters and the brightnesses of the light sources were both found to have changed appreciably with age. The observation of a magnetospheric substorm at Sanae (L ≃ 4) is used to illustrate the use of a meridian-scanning tilting-filter photometer system in auroral research. The ratio I(557.7)/ I(391.4) observed at Sanae was found to be lower than expected, as were the OJ airglow emission intensities. A prototype digital photometer system was used aboard a ship, to observe the airglow in the region of the South Atlantic Anomaly. Significant N₂⁺ lNG emissions at 391.4 nm were measured, confirming the presence of discernable particle precipitation in the region. The 0I557.7 and 630.0 nm intensities measured from the ship were found to be lower than expected. This, combined with low airglow and auroral intensities measured at Sanae, is a cause for concern. It is recommended that further checks be made regarding the brightness of the calibration sources.
- Full Text:
- Date Issued: 1992
- Authors: Dore, Ian Stuart
- Date: 1992
- Subjects: Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5494 , http://hdl.handle.net/10962/d1005280 , Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Description: This thesis describes the application of tilting-filter photometry to the study of the airglow and aurora. Previous South African photometric research is reviewed. Optical instrumentation and techniques used in airglow and auroral research are reviewed. The transmission characteristics of narrowband interference filters are discussed. The analogue meridian-scanning tilting-filter photometry system used at Sanae, Antarctica is described. Shortcomings of this system have been identified, and modifications have been made to improve its spatial and temporal resolution. Details are given of the computer-controlled digital photometry system which replaced the analogue system. Equations are derived for the conversion of raw photometric data (analogue chart deflections or digital photon counts) to absolute emission intensities. The accuracy of the intensities obtained depends on the absolute calibration of the photometer, the transmission characteristics of the filter used to isolate the spectral feature of interest, and the effects of atmospheric extinction and scattering. The influence of these factors on observed emission intensities is discussed. Various models used to determine atmospheric correction factors are reviewed. It is shown that atmospheric correction factors can have a significant effect on both emission intensities and intensity ratios. The procedure used to determine the transmission characteristics of interference filters is described, as is the procedure used to cross-calibrate secondary light sources. The transmission characteristics of the filters and the brightnesses of the light sources were both found to have changed appreciably with age. The observation of a magnetospheric substorm at Sanae (L ≃ 4) is used to illustrate the use of a meridian-scanning tilting-filter photometer system in auroral research. The ratio I(557.7)/ I(391.4) observed at Sanae was found to be lower than expected, as were the OJ airglow emission intensities. A prototype digital photometer system was used aboard a ship, to observe the airglow in the region of the South Atlantic Anomaly. Significant N₂⁺ lNG emissions at 391.4 nm were measured, confirming the presence of discernable particle precipitation in the region. The 0I557.7 and 630.0 nm intensities measured from the ship were found to be lower than expected. This, combined with low airglow and auroral intensities measured at Sanae, is a cause for concern. It is recommended that further checks be made regarding the brightness of the calibration sources.
- Full Text:
- Date Issued: 1992
Training in note making : the effects of a training scheme on first year teacher-training students
- Authors: Ferreira, Ignatius Leopold
- Date: 1992
- Subjects: Note-taking Teachers -- Training of Study skills
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1803 , http://hdl.handle.net/10962/d1003688
- Description: This research work is based upon a training technique devised and recommended by J. Smith (1985) in a pamphlet published by The British Historical Association. The technique involves training school pupils in the making of notes from text books and references and then selecting appropriate points to answer specific questions. The technique was slightly adapted and used on a small Experimental Group drawn from Black first year College of Education students at an Eastern Cape College. A Control Group from the same College received conventional lectures on two topicS from the first year college syllabus - the San and Khoi peoples of Southern Africa. The Experimental Group was given a brief training period in Smith's technique and then worked independently on extended reading passages on the same topics. Both groups received a similar introduction of a video tape on the San and a slide presentation on the Khoi. Both groups wrote the same final test after their learning experiences were over and both groups completed questionnaires on the initial visual input and on their reactions to the learning experience. Comparisons are drawn between the results and the students' reaction to those learning experiences.
- Full Text:
- Date Issued: 1992
- Authors: Ferreira, Ignatius Leopold
- Date: 1992
- Subjects: Note-taking Teachers -- Training of Study skills
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1803 , http://hdl.handle.net/10962/d1003688
- Description: This research work is based upon a training technique devised and recommended by J. Smith (1985) in a pamphlet published by The British Historical Association. The technique involves training school pupils in the making of notes from text books and references and then selecting appropriate points to answer specific questions. The technique was slightly adapted and used on a small Experimental Group drawn from Black first year College of Education students at an Eastern Cape College. A Control Group from the same College received conventional lectures on two topicS from the first year college syllabus - the San and Khoi peoples of Southern Africa. The Experimental Group was given a brief training period in Smith's technique and then worked independently on extended reading passages on the same topics. Both groups received a similar introduction of a video tape on the San and a slide presentation on the Khoi. Both groups wrote the same final test after their learning experiences were over and both groups completed questionnaires on the initial visual input and on their reactions to the learning experience. Comparisons are drawn between the results and the students' reaction to those learning experiences.
- Full Text:
- Date Issued: 1992
Transkei College of Education students' perceptions of fieldwork in geographical education
- Authors: Ngquba, Tokozile
- Date: 1992
- Subjects: Geography -- Fieldwork -- Study and teaching Teachers -- Training of -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1806 , http://hdl.handle.net/10962/d1003691
- Description: The understanding of geographical concepts and the development of skills requires the use of appropriate teaching strategies. Modern school geography incorporates a wealth of techniques and embraces a wide range of strategies which are directly suited to achieve the aims which are central to current geographical education. Techniques which directly involve the learner are perceived to be the most valuable. Of the many participatory strategies suited to the teaching of geography, fieldwork is accepted as the most worthwhile. This study investigates student teachers' perceptions of fieldwork in their college studies and as a teaching strategy. Extensive literature on fieldwork in geographical education was analysed. A survey was conducted to assess the student teachers' fieldwork experiences. The results reveal that fieldwork is neglected in Transkeian schools and Colleges of Education, despite the fact that it is required by school syllabuses, and the fact that in many areas suitable sites are readily accessible. Conclusions are drawn and recommendations made for the inclusion of fieldwork in geography courses at Transkei Colleges of Education.
- Full Text:
- Date Issued: 1992
- Authors: Ngquba, Tokozile
- Date: 1992
- Subjects: Geography -- Fieldwork -- Study and teaching Teachers -- Training of -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1806 , http://hdl.handle.net/10962/d1003691
- Description: The understanding of geographical concepts and the development of skills requires the use of appropriate teaching strategies. Modern school geography incorporates a wealth of techniques and embraces a wide range of strategies which are directly suited to achieve the aims which are central to current geographical education. Techniques which directly involve the learner are perceived to be the most valuable. Of the many participatory strategies suited to the teaching of geography, fieldwork is accepted as the most worthwhile. This study investigates student teachers' perceptions of fieldwork in their college studies and as a teaching strategy. Extensive literature on fieldwork in geographical education was analysed. A survey was conducted to assess the student teachers' fieldwork experiences. The results reveal that fieldwork is neglected in Transkeian schools and Colleges of Education, despite the fact that it is required by school syllabuses, and the fact that in many areas suitable sites are readily accessible. Conclusions are drawn and recommendations made for the inclusion of fieldwork in geography courses at Transkei Colleges of Education.
- Full Text:
- Date Issued: 1992
Understanding and treating combat-related post traumatic stress disorder: a soldier's story
- Authors: Koen, Gary
- Date: 1992
- Subjects: Post-traumatic stress disorder -- Case studies , Post-traumatic stress disorder -- Treatment , Soldiers -- Mental health -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3134 , http://hdl.handle.net/10962/d1006879 , Post-traumatic stress disorder -- Case studies , Post-traumatic stress disorder -- Treatment , Soldiers -- Mental health -- South Africa
- Description: This work documents the treatment of a 20-year-old male suffering from Post Traumatic Stress Disorder as a result of his experience during two years of national service as an Operations "Ops" Medic in the South African Defence Force. The literature review is drawn largely from the body of work emerging from the Vietnam War, and in particular the work of Robert Lifton and Erwin Parson is considered. The case study consists of a detailed synopsis of the treatment based upon material from the therapy sessions. This section hopes to accurately convey the experience of working with someone suffering from Post Traumatic Stress Disorder and provide insight into the dynamics of such a therapeutic relationship. Finally the discussion examines the links between the theory and the treatment and attempts to understand the various factors which shaped and influenced the final outcome of the therapy. Special consideration is given to showing how essentially cognitive restructuring techniques are successfully utilised within a more existential, psychodynamic framework. Furthermore, there is a paucity of literature on the subject of combat-related Post Traumatic Stress Disorder in South Africa and it is hoped that this work will both point to a need for further research in this field whilst simultaneously provide guidance for those who wish to become involved in working with individuals suffering from Post Traumatic Stress Disorder.
- Full Text:
- Date Issued: 1992
- Authors: Koen, Gary
- Date: 1992
- Subjects: Post-traumatic stress disorder -- Case studies , Post-traumatic stress disorder -- Treatment , Soldiers -- Mental health -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3134 , http://hdl.handle.net/10962/d1006879 , Post-traumatic stress disorder -- Case studies , Post-traumatic stress disorder -- Treatment , Soldiers -- Mental health -- South Africa
- Description: This work documents the treatment of a 20-year-old male suffering from Post Traumatic Stress Disorder as a result of his experience during two years of national service as an Operations "Ops" Medic in the South African Defence Force. The literature review is drawn largely from the body of work emerging from the Vietnam War, and in particular the work of Robert Lifton and Erwin Parson is considered. The case study consists of a detailed synopsis of the treatment based upon material from the therapy sessions. This section hopes to accurately convey the experience of working with someone suffering from Post Traumatic Stress Disorder and provide insight into the dynamics of such a therapeutic relationship. Finally the discussion examines the links between the theory and the treatment and attempts to understand the various factors which shaped and influenced the final outcome of the therapy. Special consideration is given to showing how essentially cognitive restructuring techniques are successfully utilised within a more existential, psychodynamic framework. Furthermore, there is a paucity of literature on the subject of combat-related Post Traumatic Stress Disorder in South Africa and it is hoped that this work will both point to a need for further research in this field whilst simultaneously provide guidance for those who wish to become involved in working with individuals suffering from Post Traumatic Stress Disorder.
- Full Text:
- Date Issued: 1992
Working with the contemptuous client in psychotherapy
- Authors: Hoffman, Elan
- Date: 1992
- Subjects: Psychotherapist and patient -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3213 , http://hdl.handle.net/10962/d1012315 , Psychotherapist and patient -- Case studies
- Description: The purpose of this case study is to explore the issue of contempt in the therapeutic relationship. The aims are twofold; namely, to illustrate to what extent the case studied throws light on existing theories on contempt in psychotherapy, and to enquire about which stance adopted by the therapist is most appropriate in the therapeutic interaction with a contemptuous client. It investigates the validity of using the case study method in examining both the content and the process of this particular course of psychotherapy. Literature on contempt in psychotherapy is reviewed, as well as the foundation-stone on which it rests, namely, the Kleinian approach to envy . The concepts of the superego and false self are also drawn upon in understanding this particular client's dynamics. The client's therapy is then presented and explored, in order to gain insight into how a psychotherapist's understanding of the contemptuous client can clarify the process of therapy. It highlights the limitations and potentialities that exist in working in this sphere of resistance, and raises questions relevant to therapists faced with these clients. The case study shows how theory in this area is helpful in understanding the contemptuous client, and that the ability of the therapist to endure and survive the contempt of the client is a crucial factor in working with the contemptuous individual.
- Full Text:
- Date Issued: 1992
- Authors: Hoffman, Elan
- Date: 1992
- Subjects: Psychotherapist and patient -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3213 , http://hdl.handle.net/10962/d1012315 , Psychotherapist and patient -- Case studies
- Description: The purpose of this case study is to explore the issue of contempt in the therapeutic relationship. The aims are twofold; namely, to illustrate to what extent the case studied throws light on existing theories on contempt in psychotherapy, and to enquire about which stance adopted by the therapist is most appropriate in the therapeutic interaction with a contemptuous client. It investigates the validity of using the case study method in examining both the content and the process of this particular course of psychotherapy. Literature on contempt in psychotherapy is reviewed, as well as the foundation-stone on which it rests, namely, the Kleinian approach to envy . The concepts of the superego and false self are also drawn upon in understanding this particular client's dynamics. The client's therapy is then presented and explored, in order to gain insight into how a psychotherapist's understanding of the contemptuous client can clarify the process of therapy. It highlights the limitations and potentialities that exist in working in this sphere of resistance, and raises questions relevant to therapists faced with these clients. The case study shows how theory in this area is helpful in understanding the contemptuous client, and that the ability of the therapist to endure and survive the contempt of the client is a crucial factor in working with the contemptuous individual.
- Full Text:
- Date Issued: 1992