Studies on the bioactivities of selected Eastern Cape seaweeds
- Authors: Carter, Anne Margaret
- Date: 1994
- Subjects: Marine algae -- South Africa -- Eastern Cape , Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4033 , http://hdl.handle.net/10962/d1004093 , Marine algae -- South Africa -- Eastern Cape , Marine algae
- Description: In studies on the bioactivities of selected eastern Cape seaweeds, a suitable extraction solvent, namely methanol was used. The antimicrobial, antineoplastic and antiviral activities were investigated, and a seasonal comparison of antimicrobial activities as well as a scanning electron microscopic study were included. A number of algae were found to display significantly high antibacterial activities, of these, the two red algae Plocamium corallorhiza and Laurencia glomerata and the two brown algae Zonaria subarticulata and Ecklonia biruncinata showed the most potent broad spectrum antibacterial activity. L.glomerata and E.biruncinata were active against all five test bacteria, but were inactive against the yeast Candida albicans. C.albicans was the most resistant organism tested,~with only Peyssonelia capensis, f-corallorhiza and Ulva rigida inhibiting its growth. Of the 17 seaweeds tested, none showed any clear seasonal changes in antimicrobial activity. The microorganisms however did vary in their susceptibility to treatment. Staphylococcus aureus and the Micrococcus species were the most susceptible to treatment by the algal extracts, with the Gram positive endospore former, Bacillus subtilis and the two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa showing more resistance to treatment. C.albicans however was the most resistant organism. In the antineoplastic studies, the brown algae Z.subarticulata, E.biruncinata and Sargassum heterophyllum showed potent activity against both the normal, LLCMK, and cancerous, mouse melanoma-3S0 cells, reducing cell growth in each case. The green algae showed potent activity against the cancerous cells, lowering growth to 30% that of the normal cells. Normal cell growth was unaffected or was stimulated by the presence of these algal extracts. The red algae showed no antineoplastic activity. Representatives of each of the red, brown and green algae were used in the brine shrimp (Artemia salina) cytotoxicity study. None of the algae showed any toxicity towards the brine shrimp. In the antiviral studies against Polio Type 1, strain L-Sa, a reduction in virus infectivity was used as an indication of the presence of antiviral properties in the seaweeds tested. This was done by comparing the virus titres of algal-treated cells with those of untreated cells. Six of the algae tested displayed antiviral activity, these were the two Rhodophyceae Hypnea spicifera and L.glomerata, the two Phaeophyceae Dictyopteris macrocarpa and Dictyota naevosa, and the two Chlorophyceae U.rigida and Halimeda cuneata. Of these, D.naevosa showed particularly strong activity, recording a log reduction in virus titre of 4.
- Full Text:
- Date Issued: 1994
- Authors: Carter, Anne Margaret
- Date: 1994
- Subjects: Marine algae -- South Africa -- Eastern Cape , Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4033 , http://hdl.handle.net/10962/d1004093 , Marine algae -- South Africa -- Eastern Cape , Marine algae
- Description: In studies on the bioactivities of selected eastern Cape seaweeds, a suitable extraction solvent, namely methanol was used. The antimicrobial, antineoplastic and antiviral activities were investigated, and a seasonal comparison of antimicrobial activities as well as a scanning electron microscopic study were included. A number of algae were found to display significantly high antibacterial activities, of these, the two red algae Plocamium corallorhiza and Laurencia glomerata and the two brown algae Zonaria subarticulata and Ecklonia biruncinata showed the most potent broad spectrum antibacterial activity. L.glomerata and E.biruncinata were active against all five test bacteria, but were inactive against the yeast Candida albicans. C.albicans was the most resistant organism tested,~with only Peyssonelia capensis, f-corallorhiza and Ulva rigida inhibiting its growth. Of the 17 seaweeds tested, none showed any clear seasonal changes in antimicrobial activity. The microorganisms however did vary in their susceptibility to treatment. Staphylococcus aureus and the Micrococcus species were the most susceptible to treatment by the algal extracts, with the Gram positive endospore former, Bacillus subtilis and the two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa showing more resistance to treatment. C.albicans however was the most resistant organism. In the antineoplastic studies, the brown algae Z.subarticulata, E.biruncinata and Sargassum heterophyllum showed potent activity against both the normal, LLCMK, and cancerous, mouse melanoma-3S0 cells, reducing cell growth in each case. The green algae showed potent activity against the cancerous cells, lowering growth to 30% that of the normal cells. Normal cell growth was unaffected or was stimulated by the presence of these algal extracts. The red algae showed no antineoplastic activity. Representatives of each of the red, brown and green algae were used in the brine shrimp (Artemia salina) cytotoxicity study. None of the algae showed any toxicity towards the brine shrimp. In the antiviral studies against Polio Type 1, strain L-Sa, a reduction in virus infectivity was used as an indication of the presence of antiviral properties in the seaweeds tested. This was done by comparing the virus titres of algal-treated cells with those of untreated cells. Six of the algae tested displayed antiviral activity, these were the two Rhodophyceae Hypnea spicifera and L.glomerata, the two Phaeophyceae Dictyopteris macrocarpa and Dictyota naevosa, and the two Chlorophyceae U.rigida and Halimeda cuneata. Of these, D.naevosa showed particularly strong activity, recording a log reduction in virus titre of 4.
- Full Text:
- Date Issued: 1994
An investigation of the effects which using the word processor has on the writing of standard six pupils
- Authors: McKenzie, Donald John
- Date: 1994
- Subjects: Written communication -- Study and teaching -- Data processing Word processors in education Language arts -- Computer-assisted instruction English language -- Writing--Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1648 , http://hdl.handle.net/10962/d1003531
- Description: In order to discover to what extent the use of the word processor affects the motivation of high school students when engaged in writing tasks, and to determine the effects of the word processing on the length and quality of their work and editing, two groups, carefully matched in terms of prior computer experience, intelligence and language ability were given eight writing tasks. The test group used word processors while the control group used pen and paper. Their behaviour was closely observed and their writing was subsequently compared. It was found that while the test group were more motivated and spent longer both writing and editing their work, the quality of the work of both groups was similar. The degree of editing was greater for the test group. The conclusion is that there is a place for the use of the word processor in the English classroom, but specific strategies need to be developed to optimise its benefits.
- Full Text:
- Date Issued: 1994
- Authors: McKenzie, Donald John
- Date: 1994
- Subjects: Written communication -- Study and teaching -- Data processing Word processors in education Language arts -- Computer-assisted instruction English language -- Writing--Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1648 , http://hdl.handle.net/10962/d1003531
- Description: In order to discover to what extent the use of the word processor affects the motivation of high school students when engaged in writing tasks, and to determine the effects of the word processing on the length and quality of their work and editing, two groups, carefully matched in terms of prior computer experience, intelligence and language ability were given eight writing tasks. The test group used word processors while the control group used pen and paper. Their behaviour was closely observed and their writing was subsequently compared. It was found that while the test group were more motivated and spent longer both writing and editing their work, the quality of the work of both groups was similar. The degree of editing was greater for the test group. The conclusion is that there is a place for the use of the word processor in the English classroom, but specific strategies need to be developed to optimise its benefits.
- Full Text:
- Date Issued: 1994
South Africa's post-apartheid foreign policy : towards a diplomacy of trade
- Authors: Dullabh, Nitesh Amratlal
- Date: 1994
- Subjects: Foreign trade regulation -- South Africa , South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2774 , http://hdl.handle.net/10962/d1002984 , Foreign trade regulation -- South Africa , South Africa -- Foreign relations
- Description: This thesis attempts to argue that a post-apartheid foreign policy will no longer be based on seeking legitimacy for the South African Government. Instead, it argues that if South Africa wants to grow, both domestically and nternationally, it will be imperative for it (South Africa) to move from an import substitution trade policy to an export-oriented trade policy. It is further suggested that the export-led strategy will be an important component for the promotion of South African international trade in the post-Cold War era. South Africa cannot improve the status of its trade regime by its own doing. It will require the support and assistance of international organizations and hence, the international community. Following the principles, rules and procedures of the General Agreement on Tariffs and Trade (GATT); it is argued, will help South Africa reconstruct its trade policies on the basis that they are free, fair and above all competitive. Furthermore, maintaining a constantly favourable relationship with the international community will allow easy access to international markets for South African goods and services, and eventually the smooth integration of the South African economy in the international political economy. This study, noting the importance of trade with a dedicated commitment to exports, concludes that although exports would flourish, there will be an immediate need for diplomats to be conversant with contemporary international trade developments. This would require diplomats to be innovative, steadfast and disciplined in their day-to-day negotiations. In the final instance, the role of trade in South Africa's future will ultimately be determined by its trade postures and the type of diplomacy to be used by its diplomats.
- Full Text:
- Date Issued: 1994
- Authors: Dullabh, Nitesh Amratlal
- Date: 1994
- Subjects: Foreign trade regulation -- South Africa , South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2774 , http://hdl.handle.net/10962/d1002984 , Foreign trade regulation -- South Africa , South Africa -- Foreign relations
- Description: This thesis attempts to argue that a post-apartheid foreign policy will no longer be based on seeking legitimacy for the South African Government. Instead, it argues that if South Africa wants to grow, both domestically and nternationally, it will be imperative for it (South Africa) to move from an import substitution trade policy to an export-oriented trade policy. It is further suggested that the export-led strategy will be an important component for the promotion of South African international trade in the post-Cold War era. South Africa cannot improve the status of its trade regime by its own doing. It will require the support and assistance of international organizations and hence, the international community. Following the principles, rules and procedures of the General Agreement on Tariffs and Trade (GATT); it is argued, will help South Africa reconstruct its trade policies on the basis that they are free, fair and above all competitive. Furthermore, maintaining a constantly favourable relationship with the international community will allow easy access to international markets for South African goods and services, and eventually the smooth integration of the South African economy in the international political economy. This study, noting the importance of trade with a dedicated commitment to exports, concludes that although exports would flourish, there will be an immediate need for diplomats to be conversant with contemporary international trade developments. This would require diplomats to be innovative, steadfast and disciplined in their day-to-day negotiations. In the final instance, the role of trade in South Africa's future will ultimately be determined by its trade postures and the type of diplomacy to be used by its diplomats.
- Full Text:
- Date Issued: 1994
Southern African Journal of Gerontology, volume 3, number 2, October 1994
- Ferreira, Monica (editor), Møller, Valerie (editor), HSRC/UCT Centre for Gerontology
- Authors: Ferreira, Monica (editor) , Møller, Valerie (editor) , HSRC/UCT Centre for Gerontology
- Date: 1994
- Subjects: Gerontology -- South Africa , Older people -- Care -- South Africa
- Language: English
- Type: Text
- Identifier: vital:8069 , http://hdl.handle.net/10962/d1012861
- Description: Intergenerational relations is not a new focus area of study in Southern Africa. Trends in changing relationships between age cohorts have been traced in family, migration and urbanization studies. This special issue of the Southern African Journal of Gerontology presents a case for studying intergenerational relations from a gerontological perspective. The issue includes work from leading international gerontologists and experts in the field of intergenerational relations writing on the United States. Two further contributions come from other parts of Africa - Ghana and Kenya. The articles on intergenerational relations in South Africa, tellingly, come from outside the field of gerontology, a point to be picked up below.
- Full Text:
- Date Issued: 1994
- Authors: Ferreira, Monica (editor) , Møller, Valerie (editor) , HSRC/UCT Centre for Gerontology
- Date: 1994
- Subjects: Gerontology -- South Africa , Older people -- Care -- South Africa
- Language: English
- Type: Text
- Identifier: vital:8069 , http://hdl.handle.net/10962/d1012861
- Description: Intergenerational relations is not a new focus area of study in Southern Africa. Trends in changing relationships between age cohorts have been traced in family, migration and urbanization studies. This special issue of the Southern African Journal of Gerontology presents a case for studying intergenerational relations from a gerontological perspective. The issue includes work from leading international gerontologists and experts in the field of intergenerational relations writing on the United States. Two further contributions come from other parts of Africa - Ghana and Kenya. The articles on intergenerational relations in South Africa, tellingly, come from outside the field of gerontology, a point to be picked up below.
- Full Text:
- Date Issued: 1994
Review of the grenadiers (Teleostei: Gadiformes) of Southern Africa, with descriptions of four new species
- Iwamoto, Tomio, Anderson, M Eric
- Authors: Iwamoto, Tomio , Anderson, M Eric
- Date: 1994
- Language: English
- Type: Text
- Identifier: vital:15023 , http://hdl.handle.net/10962/d1019883 , ISBN 0-86810-276-8 , Ichthyological Bulletin J.L.B. Smith Institute of Ichthyology; No. 61
- Description: Grenadier fishes of the families Bathygadidae and Macrouridae from southern Africa are reviewed since publication of the book Smiths’ Sea Fishes (1986). The bathygadid and macrourid fauna is increased to 46 species in 20 genera with the addition of the following new species and new records for southern Africa: Bathygadus cottoides, Caelorinchus kaiyomaru, Caelorinchus karrerrae, Caelorinchus simorhynchus sp.n, (misidentified in southern Africa as Caelorinchus fasciatus), Caelorinchus trunovi sp.n, (misidentified in southern Africa as Caelorinchus flabellispinis), Cetonurus globiceps, Co- ryphaenoides carapinus, Coryphaenoides grahami, Coryphaenoides mcmillani, Haplomacrurus nudirostris, Hymenocephalus heterolepis (uncertain identification), Malacocephalus occidentalis, Nezumia spinosa, Nezumia umbracincta sp.n., Odon- tomacrurus murrayi, Sphagemacrurus richardi, Ventrifossa mystax sp.n, (previously identified as V. sp. aff. divergens), and an indeterminate species of Ventrifossa. Name changes include: formerly Nezumia hebetata in southern Africa changed to Kumba sp.; formerly Nezumia bubonis and N. leonis now included in Kuronezumia; formerly Ventrifossa ori now Lucigadus ori; Paracetonurus sp. now Pseudonezumia sp. The species of Macrourus from southern Africa is identified as M. carinatus (Gunther, 1878). Range extensions of previously known grenadiers include Caelorinchus acanthiger far into the western Indian Ocean and Australia, C. denticulatus to Kenya, Nezumia milleri to southern Namibia, N. propinqua to Natal, Trachonurus villosus to off False Bay, western Cape Province, Ventrifossa mystax, sp. n. to the Cape west coast and V. nasuta to off Port Elizabeth. , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1994
- Authors: Iwamoto, Tomio , Anderson, M Eric
- Date: 1994
- Language: English
- Type: Text
- Identifier: vital:15023 , http://hdl.handle.net/10962/d1019883 , ISBN 0-86810-276-8 , Ichthyological Bulletin J.L.B. Smith Institute of Ichthyology; No. 61
- Description: Grenadier fishes of the families Bathygadidae and Macrouridae from southern Africa are reviewed since publication of the book Smiths’ Sea Fishes (1986). The bathygadid and macrourid fauna is increased to 46 species in 20 genera with the addition of the following new species and new records for southern Africa: Bathygadus cottoides, Caelorinchus kaiyomaru, Caelorinchus karrerrae, Caelorinchus simorhynchus sp.n, (misidentified in southern Africa as Caelorinchus fasciatus), Caelorinchus trunovi sp.n, (misidentified in southern Africa as Caelorinchus flabellispinis), Cetonurus globiceps, Co- ryphaenoides carapinus, Coryphaenoides grahami, Coryphaenoides mcmillani, Haplomacrurus nudirostris, Hymenocephalus heterolepis (uncertain identification), Malacocephalus occidentalis, Nezumia spinosa, Nezumia umbracincta sp.n., Odon- tomacrurus murrayi, Sphagemacrurus richardi, Ventrifossa mystax sp.n, (previously identified as V. sp. aff. divergens), and an indeterminate species of Ventrifossa. Name changes include: formerly Nezumia hebetata in southern Africa changed to Kumba sp.; formerly Nezumia bubonis and N. leonis now included in Kuronezumia; formerly Ventrifossa ori now Lucigadus ori; Paracetonurus sp. now Pseudonezumia sp. The species of Macrourus from southern Africa is identified as M. carinatus (Gunther, 1878). Range extensions of previously known grenadiers include Caelorinchus acanthiger far into the western Indian Ocean and Australia, C. denticulatus to Kenya, Nezumia milleri to southern Namibia, N. propinqua to Natal, Trachonurus villosus to off False Bay, western Cape Province, Ventrifossa mystax, sp. n. to the Cape west coast and V. nasuta to off Port Elizabeth. , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1994
Methods for assessing the susceptibility of freshwater ecosystems in Southern Africa to invasion by alien aquatic animals
- Authors: De Moor, Irene J
- Date: 1994
- Subjects: Biotic communities -- South Africa , Animal introduction , Freshwater ecology -- Africa, Southern , Animal introduction -- South Africa , Geographic information systems
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5300 , http://hdl.handle.net/10962/d1005145
- Description: Two methods for predicting regions susceptible to invasion by alien aquatic animals were developed for southern Africa (excluding Zimbabwe and Mozambique). In the "traditional" (data-poor) approach, distributions of three categories of alien "indicator" species (warm mesothermal, cold stenothermal and eurytopic) were compared to seven existing biogeographical models of distribution patterns of various animals in southern Africa. On the basis of these comparisons a synthesis model was developed which divided southern Africa into seven regions characterised by their susceptibility to invasion by alien aquatic animals with particular habitat requirements. In the "data-rich," geographic information systems (GIS) approach, the distribution of trout (Oncorhynchus mykiss and Salmo trutta) in selected "sampled regions" was related to elevation (as a surrogate of water temperature) and median annual rainfall (MAR) (as a surrogate of water availability). Using concentration analysis, optimum conditions for trout were identified. Regions within a larger "predictive area" which satisfied these conditions, were plotted as a digital map using the IDRISI package. Using this method seven models of potential trout distribution were generated for the following regions: northern Natal (two); southern Natal/Lesotho/Transkei (three), eastern Cape (two) and western Cape (two). Since two of the models were used to refine the methods, only five models were considered for the final assessment. In a modification of the GIS method, another model of potential trout distribution, based on mean monthly July minimum air temperature and MAR parameters, was developed for the region bounded by 29º - 34º S and 26 º - 32°E. This model showed marked similarities to another model, developed for the region bounded by 29 º - 32°S and 26º - 32°E, which was based on elevation and MAR parameters. The validity of the models developed was assessed by independent experts. Of the six models considered, four received favourable judgements, one was equivocal and one was judged to be poor. Based on these assessments it was concluded that the GIS method has credibility and could be used to develop a "data-rich" model of the susceptibility of southern Africa to invasion by alien aquatic animals. This method represents an alternative to the bioclimatic matching approach developed by scientists in Australia. The GIS method has a number of advantages over the "traditional" method: it is more amenable to testing, has greater flexibility, stores more information, produces images of a finer resolution, and can be easily updated. The traditional method has the advantage of being less expensive and requiring a less extensive database.
- Full Text:
- Date Issued: 1994
- Authors: De Moor, Irene J
- Date: 1994
- Subjects: Biotic communities -- South Africa , Animal introduction , Freshwater ecology -- Africa, Southern , Animal introduction -- South Africa , Geographic information systems
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5300 , http://hdl.handle.net/10962/d1005145
- Description: Two methods for predicting regions susceptible to invasion by alien aquatic animals were developed for southern Africa (excluding Zimbabwe and Mozambique). In the "traditional" (data-poor) approach, distributions of three categories of alien "indicator" species (warm mesothermal, cold stenothermal and eurytopic) were compared to seven existing biogeographical models of distribution patterns of various animals in southern Africa. On the basis of these comparisons a synthesis model was developed which divided southern Africa into seven regions characterised by their susceptibility to invasion by alien aquatic animals with particular habitat requirements. In the "data-rich," geographic information systems (GIS) approach, the distribution of trout (Oncorhynchus mykiss and Salmo trutta) in selected "sampled regions" was related to elevation (as a surrogate of water temperature) and median annual rainfall (MAR) (as a surrogate of water availability). Using concentration analysis, optimum conditions for trout were identified. Regions within a larger "predictive area" which satisfied these conditions, were plotted as a digital map using the IDRISI package. Using this method seven models of potential trout distribution were generated for the following regions: northern Natal (two); southern Natal/Lesotho/Transkei (three), eastern Cape (two) and western Cape (two). Since two of the models were used to refine the methods, only five models were considered for the final assessment. In a modification of the GIS method, another model of potential trout distribution, based on mean monthly July minimum air temperature and MAR parameters, was developed for the region bounded by 29º - 34º S and 26 º - 32°E. This model showed marked similarities to another model, developed for the region bounded by 29 º - 32°S and 26º - 32°E, which was based on elevation and MAR parameters. The validity of the models developed was assessed by independent experts. Of the six models considered, four received favourable judgements, one was equivocal and one was judged to be poor. Based on these assessments it was concluded that the GIS method has credibility and could be used to develop a "data-rich" model of the susceptibility of southern Africa to invasion by alien aquatic animals. This method represents an alternative to the bioclimatic matching approach developed by scientists in Australia. The GIS method has a number of advantages over the "traditional" method: it is more amenable to testing, has greater flexibility, stores more information, produces images of a finer resolution, and can be easily updated. The traditional method has the advantage of being less expensive and requiring a less extensive database.
- Full Text:
- Date Issued: 1994
Perceptions of language teaching in science from student and teacher discourse
- Authors: Garraway, James Windsor
- Date: 1994
- Subjects: Physics -- Study and teaching -- South Africa Language arts -- South Africa Written communication -- Study and teaching -- South Africa Language arts -- Correlation with content subjects -- South Africa Physics teachers -- Language
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1693 , http://hdl.handle.net/10962/d1003576
- Description: The research was concerned with perceptions of language and physics in three strata of participants in a writing across the curriculum teaching course at an intermediate college. The participants were: a language teacher, two physics teachers and a class of twenty physics students - the students were studying in order to enter the Engineering Faculty at the University of Cape Town. The predominant understanding of the teachers was that of a limited interpenetration between the discourse of physics and language teaching. Physics teachers thought that language teachers would experience difficulties with both the concepts and language of physics. In actual practice however, students and the language teacher managed physics knowledge with some degree of success in the language classroom. Some students understood writing as helping them to understand physics. However, the dominant understanding of language was that of knowing the appropriate language of physics for their teachers. An appropriate language understanding was seen as potentially problematic in that it could encourage an unquestioning or monodimensional approach to physics knowledge. As a way around this problem, it was suggested that language teachers teach students to recognise and to use particular genres within science, and to develop their voice within these constraints.
- Full Text:
- Date Issued: 1994
- Authors: Garraway, James Windsor
- Date: 1994
- Subjects: Physics -- Study and teaching -- South Africa Language arts -- South Africa Written communication -- Study and teaching -- South Africa Language arts -- Correlation with content subjects -- South Africa Physics teachers -- Language
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1693 , http://hdl.handle.net/10962/d1003576
- Description: The research was concerned with perceptions of language and physics in three strata of participants in a writing across the curriculum teaching course at an intermediate college. The participants were: a language teacher, two physics teachers and a class of twenty physics students - the students were studying in order to enter the Engineering Faculty at the University of Cape Town. The predominant understanding of the teachers was that of a limited interpenetration between the discourse of physics and language teaching. Physics teachers thought that language teachers would experience difficulties with both the concepts and language of physics. In actual practice however, students and the language teacher managed physics knowledge with some degree of success in the language classroom. Some students understood writing as helping them to understand physics. However, the dominant understanding of language was that of knowing the appropriate language of physics for their teachers. An appropriate language understanding was seen as potentially problematic in that it could encourage an unquestioning or monodimensional approach to physics knowledge. As a way around this problem, it was suggested that language teachers teach students to recognise and to use particular genres within science, and to develop their voice within these constraints.
- Full Text:
- Date Issued: 1994
Comparative aspects of the reproductive biology of seabreams (Pisces: Sparidae)
- Authors: Garratt, Patrick Ashworth
- Date: 1994
- Subjects: Sparidae -- Physiology Sparidae -- Reproduction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5245 , http://hdl.handle.net/10962/d1005088
- Description: Sexuality in seabreams (Sparidae) is considered to be more complex than in any other family of fishes. Early work indicated five reproductive styles within the family: protandry, protogyny, simultaneous hermaphroditism, rudimentary hermaphroditism and gonochorism. More recently two reproductive styles have been suggested: sex change (protandry and protogyny) and secondary gonochorism (rudimentary hermaphrodites). The need for detailed descriptions of sex differentiation, gonad development and spawning behaviour in this family has been identified by a number of workers in this field. The aims of the present study were: i) to provide accurate, detailed descriptions and comparisons of gonadal development in representatives of each reproductive style, ii) to investigate their spawning strategies, and iii) to relate these findings to current theories on hermaphroditism and sex change in fishes. Four species were investigated. Slinger, Chrysoblephus puniceus, the only known protogynous hermaphrodite in Natal. Santer, Cheimerius nufar, described in the literature as a rudimentary hermaphrodite. Riverbream, Acanthopagrus berda suspected to be a protandrous hermaphrodite. Natal stump nose, Rhabdosargus sarba, reported elsewhere as a protandrous hermaphrodite. Detailed histological analysis showed that morphological and cytological development of all gonads proceeded initially in a female direction, irrespective of reproductive style, but that differentiating gonads of protandrous and protogynous hermaphrodites could easily be distinguished from one another. Early gonadal development was similar in R. sarba and A. berda with gonadal primordia differentiating into distinctly bisexual organs. In C. puniceus and C. nufar gonadal primordia differentiated into ovaries with reduced, inert male elements in the tunica albuginea. Sex differentiation occurred relatively late (100-150mm fork length) in all the species investigated. Few cells conforming to primordial germ cells (PGC's) described in other teleosts were identified. These cells only became evident after the appearance of gonial cells and their identity is questioned. Gonial cells appeared to develop within less-electron-dense cysts of cells. Gonial cells in presumptive male and female elements could not be distinguished from one another morphologically, suggesting the bipotentiality of these cells. All R. sarba and A. berda gonads pass through a predominantly male phase and all fish function first as males, indicating protandrous sex change in both species. All C. puniceus and C. nufar gonads develop initially into ovaries. Sex change thus occurs in both species and protogyny in C. puniceus is confirmed. In C. nufar, sex change may occur before or after sexual maturity and its reproductive style remains uncertain. Investigations into the spawning habits of A. berda have shown that this species spawns inside the Kosi estuary at night. Eggs are released during peak ebb tides. Spawning occurs in large aggregations and several to many males compete to spawn with individual females. This spawning strategy does not conform to predictions made from the size advantage model for protandrous species. Chrysoblephus puniceus appears to have preferential spawning sites on down-current outer reef margins. Spawning was not observed in this species, but changes in behaviour, social structure and colour during the spawning season suggest that it may have a mating system similar to several protogynous labrids and scarids, in which territories are temporary. Cheimerius nufar has a similar mating system. Temporary territories are established by large males during the spawning season, which extends from August to November. Mating is by pair-spawning and dominant territorial males obtain a disproportionate number of matings. 'Streaking' appears to represent an alternative mating strategy for males until they attain a sufficient size to establish and defend territories. The mating pattern of C. nufar suggests that it is either a gonochorist which does not conform to current theoretical predictions; or that it is a protogynous hermaphrodite incorrectly diagnosed as a rudimentary hermaphrodite; or that protogyny in the Sparidae is an ancestral condition and C. nufar is in the process of evolutionary change from a protogynous to a gonochoristic form (or visa versa).
- Full Text:
- Date Issued: 1994
- Authors: Garratt, Patrick Ashworth
- Date: 1994
- Subjects: Sparidae -- Physiology Sparidae -- Reproduction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5245 , http://hdl.handle.net/10962/d1005088
- Description: Sexuality in seabreams (Sparidae) is considered to be more complex than in any other family of fishes. Early work indicated five reproductive styles within the family: protandry, protogyny, simultaneous hermaphroditism, rudimentary hermaphroditism and gonochorism. More recently two reproductive styles have been suggested: sex change (protandry and protogyny) and secondary gonochorism (rudimentary hermaphrodites). The need for detailed descriptions of sex differentiation, gonad development and spawning behaviour in this family has been identified by a number of workers in this field. The aims of the present study were: i) to provide accurate, detailed descriptions and comparisons of gonadal development in representatives of each reproductive style, ii) to investigate their spawning strategies, and iii) to relate these findings to current theories on hermaphroditism and sex change in fishes. Four species were investigated. Slinger, Chrysoblephus puniceus, the only known protogynous hermaphrodite in Natal. Santer, Cheimerius nufar, described in the literature as a rudimentary hermaphrodite. Riverbream, Acanthopagrus berda suspected to be a protandrous hermaphrodite. Natal stump nose, Rhabdosargus sarba, reported elsewhere as a protandrous hermaphrodite. Detailed histological analysis showed that morphological and cytological development of all gonads proceeded initially in a female direction, irrespective of reproductive style, but that differentiating gonads of protandrous and protogynous hermaphrodites could easily be distinguished from one another. Early gonadal development was similar in R. sarba and A. berda with gonadal primordia differentiating into distinctly bisexual organs. In C. puniceus and C. nufar gonadal primordia differentiated into ovaries with reduced, inert male elements in the tunica albuginea. Sex differentiation occurred relatively late (100-150mm fork length) in all the species investigated. Few cells conforming to primordial germ cells (PGC's) described in other teleosts were identified. These cells only became evident after the appearance of gonial cells and their identity is questioned. Gonial cells appeared to develop within less-electron-dense cysts of cells. Gonial cells in presumptive male and female elements could not be distinguished from one another morphologically, suggesting the bipotentiality of these cells. All R. sarba and A. berda gonads pass through a predominantly male phase and all fish function first as males, indicating protandrous sex change in both species. All C. puniceus and C. nufar gonads develop initially into ovaries. Sex change thus occurs in both species and protogyny in C. puniceus is confirmed. In C. nufar, sex change may occur before or after sexual maturity and its reproductive style remains uncertain. Investigations into the spawning habits of A. berda have shown that this species spawns inside the Kosi estuary at night. Eggs are released during peak ebb tides. Spawning occurs in large aggregations and several to many males compete to spawn with individual females. This spawning strategy does not conform to predictions made from the size advantage model for protandrous species. Chrysoblephus puniceus appears to have preferential spawning sites on down-current outer reef margins. Spawning was not observed in this species, but changes in behaviour, social structure and colour during the spawning season suggest that it may have a mating system similar to several protogynous labrids and scarids, in which territories are temporary. Cheimerius nufar has a similar mating system. Temporary territories are established by large males during the spawning season, which extends from August to November. Mating is by pair-spawning and dominant territorial males obtain a disproportionate number of matings. 'Streaking' appears to represent an alternative mating strategy for males until they attain a sufficient size to establish and defend territories. The mating pattern of C. nufar suggests that it is either a gonochorist which does not conform to current theoretical predictions; or that it is a protogynous hermaphrodite incorrectly diagnosed as a rudimentary hermaphrodite; or that protogyny in the Sparidae is an ancestral condition and C. nufar is in the process of evolutionary change from a protogynous to a gonochoristic form (or visa versa).
- Full Text:
- Date Issued: 1994
The impact of the end of the Cold War on transition in South Africa
- Authors: Du Preez, Roni
- Date: 1994
- Subjects: Cold War , International relations , South Africa -- Politics and government -- 1989-1994 , South Africa -- Foreign relations -- 1989-1994 , South Africa -- Politics and government -- 1978-1989 , South Africa -- Foreign relations -- 1978-1989
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2773 , http://hdl.handle.net/10962/d1002983 , Cold War , International relations , South Africa -- Politics and government -- 1989-1994 , South Africa -- Foreign relations -- 1989-1994 , South Africa -- Politics and government -- 1978-1989 , South Africa -- Foreign relations -- 1978-1989
- Description: This thesis argues that F.W. de Klerk's historic February 1990 speech was the end product of a set of circumstances in recent South African and global history which made possible the new phase of transitional politics which South Africa is currently experiencing. It seeks to establish that of all the factors that contributed to change, it was the late 1980s thaw in the Cold War, and its resultant repercussions internationally and regionally which was the catalytic factor which made the new era possible. In all the literature on transition there has been no comprehensive analysis of the plausible link between the two superpowers agreeing in the mid-1980s to abandon confrontational practices and to change their approaches to regional conflicts and the South African government agreeing to negotiate for a new political dispensation. This thesis will seek to establish and analyse such a link. By 1986 there was in certain governmental circles a non-public view that the policy of apartheid had failed both as a solution to the problem of black political aspirations and as a legitimating ideology. Constraining any serious move towards political change was a widely held fear at the top level of government that an accelerated reform process would make South Africa vulnerable to external aggression and internal revolutionary forces. This thesis suggests that the collapse of communist rule in Eastern Europe and the 'new political thinking' in Soviet foreign policy resulted in the notion of a communist-inspired total onslaught against South Africa losing currency - as did the position of those within the ruling elite who remained dogmatically attached to it. The end of the Cold War is the common thread which links South Africa's international , regional and domestic environments. Two important events occurred in the international and regional arenas, which against the backdrop of the end of the Cold War, strengthened the credibility of the alternative view in government: (i) the October 1986 Reykjavik Summit and (ii) the South African Defence Force setback at Cuito Cuanavale. P.W. Botha's resignation as leader of the National Party and soon after as State President created the political space through which the view of the reformers could emerge as dominant. Recognising that neither the international nor regional environments sustained the beliefs and fears held by the military hawks, F.W. de Klerk was able to capitalise on the ambience of negotiations and apply it to the South African situation. De Klerk's February 1990 speech was therefore the culmination of a process which had its origins in the mid-1980's.
- Full Text:
- Date Issued: 1994
- Authors: Du Preez, Roni
- Date: 1994
- Subjects: Cold War , International relations , South Africa -- Politics and government -- 1989-1994 , South Africa -- Foreign relations -- 1989-1994 , South Africa -- Politics and government -- 1978-1989 , South Africa -- Foreign relations -- 1978-1989
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2773 , http://hdl.handle.net/10962/d1002983 , Cold War , International relations , South Africa -- Politics and government -- 1989-1994 , South Africa -- Foreign relations -- 1989-1994 , South Africa -- Politics and government -- 1978-1989 , South Africa -- Foreign relations -- 1978-1989
- Description: This thesis argues that F.W. de Klerk's historic February 1990 speech was the end product of a set of circumstances in recent South African and global history which made possible the new phase of transitional politics which South Africa is currently experiencing. It seeks to establish that of all the factors that contributed to change, it was the late 1980s thaw in the Cold War, and its resultant repercussions internationally and regionally which was the catalytic factor which made the new era possible. In all the literature on transition there has been no comprehensive analysis of the plausible link between the two superpowers agreeing in the mid-1980s to abandon confrontational practices and to change their approaches to regional conflicts and the South African government agreeing to negotiate for a new political dispensation. This thesis will seek to establish and analyse such a link. By 1986 there was in certain governmental circles a non-public view that the policy of apartheid had failed both as a solution to the problem of black political aspirations and as a legitimating ideology. Constraining any serious move towards political change was a widely held fear at the top level of government that an accelerated reform process would make South Africa vulnerable to external aggression and internal revolutionary forces. This thesis suggests that the collapse of communist rule in Eastern Europe and the 'new political thinking' in Soviet foreign policy resulted in the notion of a communist-inspired total onslaught against South Africa losing currency - as did the position of those within the ruling elite who remained dogmatically attached to it. The end of the Cold War is the common thread which links South Africa's international , regional and domestic environments. Two important events occurred in the international and regional arenas, which against the backdrop of the end of the Cold War, strengthened the credibility of the alternative view in government: (i) the October 1986 Reykjavik Summit and (ii) the South African Defence Force setback at Cuito Cuanavale. P.W. Botha's resignation as leader of the National Party and soon after as State President created the political space through which the view of the reformers could emerge as dominant. Recognising that neither the international nor regional environments sustained the beliefs and fears held by the military hawks, F.W. de Klerk was able to capitalise on the ambience of negotiations and apply it to the South African situation. De Klerk's February 1990 speech was therefore the culmination of a process which had its origins in the mid-1980's.
- Full Text:
- Date Issued: 1994
Up Beat Issue Number 4 1994
- SACHED
- Authors: SACHED
- Date: 1994
- Subjects: SACHED
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/115656 , vital:34211
- Description: Well, here we are, a month after the elections. Let us pray that everyone in our country will be able to put their differences behind them and work together to build a better South Africa. In this issue of Upbeat we speak to young people about the violence in Bophuthatswana before the elections. But there are also lots of fun stories for you to read. Meet Toni Braxton and find out more a sport that is taking over in South Africa - basketball. Finally there is a story about smoking and what it does to your body on page 12. If you are a beginner smoker, do the quiz at the end of the story and see if you really want to smoke.
- Full Text:
- Date Issued: 1994
- Authors: SACHED
- Date: 1994
- Subjects: SACHED
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/115656 , vital:34211
- Description: Well, here we are, a month after the elections. Let us pray that everyone in our country will be able to put their differences behind them and work together to build a better South Africa. In this issue of Upbeat we speak to young people about the violence in Bophuthatswana before the elections. But there are also lots of fun stories for you to read. Meet Toni Braxton and find out more a sport that is taking over in South Africa - basketball. Finally there is a story about smoking and what it does to your body on page 12. If you are a beginner smoker, do the quiz at the end of the story and see if you really want to smoke.
- Full Text:
- Date Issued: 1994
Site Tax Campaign Manual
- COSATU
- Authors: COSATU
- Date: 1994
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/137159 , vital:37493
- Description: Since 1989 most workers in South Africa have had their wages taxed under the Site Tax system. SITE stands for Standard Income Tax on Employees. Under the Site Tax system, the employer is responsible for making sure that workers pay the correct, amount of tax. This is different from the old Pay As You Earn (PAYE) system where the Receiver of Revenue had to make sure that the amount of tax paid was correct. Now the employer works out how much tax has to be paid from the personal information, such as number of children, given to them by each worker. But COSATU has seen that many workers have been taxed too much by their employers. This is mostly because no-one has explained to workers how the Site Tax system works and what tax reductions they are entitled to.
- Full Text:
- Date Issued: 1994
- Authors: COSATU
- Date: 1994
- Subjects: COSATU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/137159 , vital:37493
- Description: Since 1989 most workers in South Africa have had their wages taxed under the Site Tax system. SITE stands for Standard Income Tax on Employees. Under the Site Tax system, the employer is responsible for making sure that workers pay the correct, amount of tax. This is different from the old Pay As You Earn (PAYE) system where the Receiver of Revenue had to make sure that the amount of tax paid was correct. Now the employer works out how much tax has to be paid from the personal information, such as number of children, given to them by each worker. But COSATU has seen that many workers have been taxed too much by their employers. This is mostly because no-one has explained to workers how the Site Tax system works and what tax reductions they are entitled to.
- Full Text:
- Date Issued: 1994
Uncertainty and fear - but restoration completed
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6169 , http://hdl.handle.net/10962/d1012359
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1994
- Authors: Lewis, Colin A
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6169 , http://hdl.handle.net/10962/d1012359
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1994
The search for an ionospheric model suitable for real-time applications in HF radio communications
- Mercer, Christopher Crossley
- Authors: Mercer, Christopher Crossley
- Date: 1994
- Subjects: Ionospheric radio wave propagation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5488 , http://hdl.handle.net/10962/d1005274 , Ionospheric radio wave propagation
- Description: Statement of work: In essence the research work was to focus on the development of an ionospheric model suitable for real time HF frequency prediction and direction finding applications. The modelling of the ionosphere had to be generic in nature, sufficient to ensure that the CSIR could simultaneously secure commercial competitiveness in each of the three niche market areas aforementioned, while requiring only minimal changes to software architecture in the case of each application. A little research quickly showed that the development of an ionospheric model capable of driving a HFDFSSL system in "real time" would result in one having to make only slight re-structuring of the software to facilitate application of the same model in the areas of real time frequency prediction and spectrum management. The decision made at the outset of the project to slant the research toward the development of a model best suited for HF direction finding applications is reflected in the avenues followed during the course of the modelling process
- Full Text:
- Date Issued: 1994
- Authors: Mercer, Christopher Crossley
- Date: 1994
- Subjects: Ionospheric radio wave propagation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5488 , http://hdl.handle.net/10962/d1005274 , Ionospheric radio wave propagation
- Description: Statement of work: In essence the research work was to focus on the development of an ionospheric model suitable for real time HF frequency prediction and direction finding applications. The modelling of the ionosphere had to be generic in nature, sufficient to ensure that the CSIR could simultaneously secure commercial competitiveness in each of the three niche market areas aforementioned, while requiring only minimal changes to software architecture in the case of each application. A little research quickly showed that the development of an ionospheric model capable of driving a HFDFSSL system in "real time" would result in one having to make only slight re-structuring of the software to facilitate application of the same model in the areas of real time frequency prediction and spectrum management. The decision made at the outset of the project to slant the research toward the development of a model best suited for HF direction finding applications is reflected in the avenues followed during the course of the modelling process
- Full Text:
- Date Issued: 1994
Ideology, hegemony, and Xhosa written poetry, 1948-1990
- Authors: Mona, Godfrey Vulindlela
- Date: 1994
- Subjects: Xhosa poetry -- History and criticism , Protest poetry, Xhosa -- History and criticism , Ideology and literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3597 , http://hdl.handle.net/10962/d1002172 , Xhosa poetry -- History and criticism , Protest poetry, Xhosa -- History and criticism , Ideology and literature
- Description: This interdisciplinary study locates Xhosa written poetry (1948-1990) within the framework of the socio-politico-economic scenario in South Africa. It sets out to examine the impact of the above stated factors on literature, by supporting the hypothesis that Xhosa written poetry of the Apartheid epoch is a terrain of the struggle for hegemony between the dominant ideology and the alternative ideologies.
- Full Text:
- Date Issued: 1994
- Authors: Mona, Godfrey Vulindlela
- Date: 1994
- Subjects: Xhosa poetry -- History and criticism , Protest poetry, Xhosa -- History and criticism , Ideology and literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3597 , http://hdl.handle.net/10962/d1002172 , Xhosa poetry -- History and criticism , Protest poetry, Xhosa -- History and criticism , Ideology and literature
- Description: This interdisciplinary study locates Xhosa written poetry (1948-1990) within the framework of the socio-politico-economic scenario in South Africa. It sets out to examine the impact of the above stated factors on literature, by supporting the hypothesis that Xhosa written poetry of the Apartheid epoch is a terrain of the struggle for hegemony between the dominant ideology and the alternative ideologies.
- Full Text:
- Date Issued: 1994
The Quakers in South Africa a social witness
- Authors: Tonsing, Betty Kathryn
- Date: 1994
- Subjects: Society of Friends Quakers -- History Quakers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2564 , http://hdl.handle.net/10962/d1002417
- Description: The Religious Society of Friends, or Quakers, began their witness in the 1600s during a time of religious debate when competing doctrines reflected the political, social and intellectual turmoil of seventeenth-century England. George Fox (1624-1691), the founder, preached that people are guided by God's inner light which is present in the hearts and conscience of all people and reflects God's 'divine' will. The Quakers form a small religious membership not larger than 200,000 people sect, its world-wide. Yet, historically, the group's impact on social issues has always outweighed its numerical strength. The earliest Quakers to reside more permanently in South Africa were British settlers, several of whom became outspoken civic leaders. Quaker humanitarian gestures led to the opening of a multi-racial school for poor children in Cape Town (1840) and investigations into the treatment of Afrikaner women and children in concentration camps during the Anglo-Boer War (1899-1902). Early Quakers are also credited with initiating the Joint Council Movement of Europeans and Africans (1920s), forerunner to the South African Institute of Race Relations. This study traces the Quaker presence in South Africa from its earliest history to the present, with particular emphasis on the twentieth century. Specifically, the examination of the Quaker presence addresses the group's reaction to South African society and politics in reference to segregationist and apartheid legislation. The study includes a comparative analysis of the response among South African Quakers to these issues with Quaker response in England and the United states. The purpose of this analysis is to attempt an assessment of the extent to which South African Quaker practices were consistent with the philosophies of their world-wide religious fellowship. Relevant to the Quaker belief in peace and justice for all, with no discrimination, specific issues that involved South African Quakers and for which sufficient primary sources were available are closely examined. Of particular interest is the opening of a Quaker boarding school during the early 1930s, the Quaker response to the Defiance Campaign in 1952, and South African Quaker response to the call for international sanctions and boycotts against South Africa. More recent Quaker activities, including mediation between the African National Congress and the government, provide significant data. South African Quakers have defined themselves as members of a religious body whose belief of pacifism and commitment to non-violence dictates to a certain extent their obedience to a higher authority -- which some call their conscience and others call God -- if a civil law is deemed immoral and unjust . Thus, the study seeks to define the individual and corporate Quaker witness in South Africa in relation to the Society's principles.
- Full Text:
- Date Issued: 1994
- Authors: Tonsing, Betty Kathryn
- Date: 1994
- Subjects: Society of Friends Quakers -- History Quakers -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2564 , http://hdl.handle.net/10962/d1002417
- Description: The Religious Society of Friends, or Quakers, began their witness in the 1600s during a time of religious debate when competing doctrines reflected the political, social and intellectual turmoil of seventeenth-century England. George Fox (1624-1691), the founder, preached that people are guided by God's inner light which is present in the hearts and conscience of all people and reflects God's 'divine' will. The Quakers form a small religious membership not larger than 200,000 people sect, its world-wide. Yet, historically, the group's impact on social issues has always outweighed its numerical strength. The earliest Quakers to reside more permanently in South Africa were British settlers, several of whom became outspoken civic leaders. Quaker humanitarian gestures led to the opening of a multi-racial school for poor children in Cape Town (1840) and investigations into the treatment of Afrikaner women and children in concentration camps during the Anglo-Boer War (1899-1902). Early Quakers are also credited with initiating the Joint Council Movement of Europeans and Africans (1920s), forerunner to the South African Institute of Race Relations. This study traces the Quaker presence in South Africa from its earliest history to the present, with particular emphasis on the twentieth century. Specifically, the examination of the Quaker presence addresses the group's reaction to South African society and politics in reference to segregationist and apartheid legislation. The study includes a comparative analysis of the response among South African Quakers to these issues with Quaker response in England and the United states. The purpose of this analysis is to attempt an assessment of the extent to which South African Quaker practices were consistent with the philosophies of their world-wide religious fellowship. Relevant to the Quaker belief in peace and justice for all, with no discrimination, specific issues that involved South African Quakers and for which sufficient primary sources were available are closely examined. Of particular interest is the opening of a Quaker boarding school during the early 1930s, the Quaker response to the Defiance Campaign in 1952, and South African Quaker response to the call for international sanctions and boycotts against South Africa. More recent Quaker activities, including mediation between the African National Congress and the government, provide significant data. South African Quakers have defined themselves as members of a religious body whose belief of pacifism and commitment to non-violence dictates to a certain extent their obedience to a higher authority -- which some call their conscience and others call God -- if a civil law is deemed immoral and unjust . Thus, the study seeks to define the individual and corporate Quaker witness in South Africa in relation to the Society's principles.
- Full Text:
- Date Issued: 1994
Synthetic and spectroscopic studies of 1,4-benzodiazepine analogues
- Authors: Mphahlele, Malose Jack
- Date: 1994
- Subjects: Benzodiazepines Tranquilizing drugs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4384 , http://hdl.handle.net/10962/d1005049
- Description: In this project, an extensive range of benzodiazepine analogues have been synthesised via Schmidt reaction of specially prepared flavanone, 4-quinolone and l-thioflavanone precursors; nitrogen insertion being effected by use of trimethylsilyl azide in trifluoroacetic acid. In some cases, several of the benzodiazepine analogues have also been prepared by alternative cyclisation routes. A detailed kinetic-mechanistic study of the Schmidt reaction of flavanones has been carried out using 'H NMR spectroscopy to explain the observed regiochemistry of nitrogen insertion. The reaction rates, for the formation of both amide and tetrazolo derivatives have been found to be influenced by the electronic effects of the A- and B-ring substituents. A series of benzodiazepine analogues have been shown to undergo regioselective A-ring chlorination with t-butylhypochlorite; the products being characterised by 'H NMR, IR and mass spectroscopy. The mass spectrometric fragmentation patterns of series of 2-aryl-4-quinolones, and 2-aryl-l ,4-benzodiazepinones and their tetrazolo[l ,5-dl analogues have been elucidated using a combination of low-resolution, high-resolution and metastable-peak analyses. The binding affinities of various benzodiazepine analogues for rat brain benzodiazepine receptors have been evaluated using a radioreceptor assay technique. Structure-activity relationships were investigated to establish the effects of various A-, B- and Coring substituents on binding affinity. The conformational preferences of selected systems have been studied using a combination of multi-pulse 'H NMR spectroscopy, X-ray crystallography and computer modelling techniques with a view to establishing the influence of conformation on binding affinity.
- Full Text:
- Date Issued: 1994
- Authors: Mphahlele, Malose Jack
- Date: 1994
- Subjects: Benzodiazepines Tranquilizing drugs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4384 , http://hdl.handle.net/10962/d1005049
- Description: In this project, an extensive range of benzodiazepine analogues have been synthesised via Schmidt reaction of specially prepared flavanone, 4-quinolone and l-thioflavanone precursors; nitrogen insertion being effected by use of trimethylsilyl azide in trifluoroacetic acid. In some cases, several of the benzodiazepine analogues have also been prepared by alternative cyclisation routes. A detailed kinetic-mechanistic study of the Schmidt reaction of flavanones has been carried out using 'H NMR spectroscopy to explain the observed regiochemistry of nitrogen insertion. The reaction rates, for the formation of both amide and tetrazolo derivatives have been found to be influenced by the electronic effects of the A- and B-ring substituents. A series of benzodiazepine analogues have been shown to undergo regioselective A-ring chlorination with t-butylhypochlorite; the products being characterised by 'H NMR, IR and mass spectroscopy. The mass spectrometric fragmentation patterns of series of 2-aryl-4-quinolones, and 2-aryl-l ,4-benzodiazepinones and their tetrazolo[l ,5-dl analogues have been elucidated using a combination of low-resolution, high-resolution and metastable-peak analyses. The binding affinities of various benzodiazepine analogues for rat brain benzodiazepine receptors have been evaluated using a radioreceptor assay technique. Structure-activity relationships were investigated to establish the effects of various A-, B- and Coring substituents on binding affinity. The conformational preferences of selected systems have been studied using a combination of multi-pulse 'H NMR spectroscopy, X-ray crystallography and computer modelling techniques with a view to establishing the influence of conformation on binding affinity.
- Full Text:
- Date Issued: 1994
An evaluation of case study teaching materials on hazards: based on the current aims of geographical education
- Authors: Pyle, Desmond Mark
- Date: 1994
- Subjects: Geography -- Study and teaching (Secondary) -- South Africa Disasters -- Study and teaching -- South Africa Hazardous geographic environments -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1524 , http://hdl.handle.net/10962/d1003406
- Description: Hazards are an integral part of people-environment relationships. The impact of hazards locally and globally has become increasinglymore severe. particularly in the previous two decades. This is largely as a result of unwise human intervention in natural systems. The study of hazards at secondary school level affords valuable opportunities for learning about people-environment issues. This in turn, can promote a greater awareness of environmental problems. One of the most important current aims of Geographical Education is the development of critical thinking skills in pupils. Such skills are vital for equipping pupils with the necessary tools to understand and participate in solving the world's increasing human and environmental problems. The development of a critical faculty in pupils is best achieved by the use of learner-based participatory teaching strategies where pupils are involved in problem solving activities. Research has shown that British and South African Geography curricula reflect current thinking in Geographical education and learning theory. The 1992 Junior Secondary Geography Syllabus in line with these trends. includes a section for study on hazards. Hazards are presented primarily as case studies in modern Geographical texts. which is seen as one of the most effective ways of teaching hazards. Research however suggests that South African textbooks have certain shortcomings. notwithstanding the importance placed on textbooks by teachers in this country. This study investigated the extent to which case study teaching materials on hazards are optimising opportunities available for effective learning within an Environmental Paradigm. An evaluation methodology, which is believed to have value for use by other researchers, was developed to suit the specific requirements of the study. The study findings reveal a poor realisation of the current aims of Geographical Education and learning theory, regarding the South African teaching materials. Recommendations are made improvements in the development and use of local case teaching materials. Guidelines for the development of for study local materials are provided from case studies in British texts and from methods developed by the researcher.
- Full Text:
- Date Issued: 1994
- Authors: Pyle, Desmond Mark
- Date: 1994
- Subjects: Geography -- Study and teaching (Secondary) -- South Africa Disasters -- Study and teaching -- South Africa Hazardous geographic environments -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1524 , http://hdl.handle.net/10962/d1003406
- Description: Hazards are an integral part of people-environment relationships. The impact of hazards locally and globally has become increasinglymore severe. particularly in the previous two decades. This is largely as a result of unwise human intervention in natural systems. The study of hazards at secondary school level affords valuable opportunities for learning about people-environment issues. This in turn, can promote a greater awareness of environmental problems. One of the most important current aims of Geographical Education is the development of critical thinking skills in pupils. Such skills are vital for equipping pupils with the necessary tools to understand and participate in solving the world's increasing human and environmental problems. The development of a critical faculty in pupils is best achieved by the use of learner-based participatory teaching strategies where pupils are involved in problem solving activities. Research has shown that British and South African Geography curricula reflect current thinking in Geographical education and learning theory. The 1992 Junior Secondary Geography Syllabus in line with these trends. includes a section for study on hazards. Hazards are presented primarily as case studies in modern Geographical texts. which is seen as one of the most effective ways of teaching hazards. Research however suggests that South African textbooks have certain shortcomings. notwithstanding the importance placed on textbooks by teachers in this country. This study investigated the extent to which case study teaching materials on hazards are optimising opportunities available for effective learning within an Environmental Paradigm. An evaluation methodology, which is believed to have value for use by other researchers, was developed to suit the specific requirements of the study. The study findings reveal a poor realisation of the current aims of Geographical Education and learning theory, regarding the South African teaching materials. Recommendations are made improvements in the development and use of local case teaching materials. Guidelines for the development of for study local materials are provided from case studies in British texts and from methods developed by the researcher.
- Full Text:
- Date Issued: 1994
Perceptions of environmental education among senior Ciskeian educationists, and the implications for educational change in the Ciskei region
- Authors: Mkala-Pholo, Pumla Patricia
- Date: 1994
- Subjects: Environmental education -- South Africa -- Ciskei Environmental education -- Curricula -- South Africa -- Ciskei Educators -- South Africa -- Ciskei -- Attitudes Educational planning -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1692 , http://hdl.handle.net/10962/d1003575
- Description: This study was conducted to investigate perceptions of Environmental Education among senior Ciskeian educationists, and to explore the possibility of implementing Environmental Education in school and college curricula in the Ciskei region. Data was collected from interviews with a sample of senior Ciskeian educationists, then analysed and assessed. Corroborating information was obtained from attendance at several regional workshops organised by the Environmental Education Policy Initiative. The data indicated a sound general awareness of environmental problems in Ciskei and a belief in Environmental Education as a means toward their solution. Although the interviewees' understanding of Environmental Education was imperfect, there was broad support for its aims and principles. Since the study was motivated by concern about the implementation of Environmental Education in Ciskei, the results obtained were encouraging.
- Full Text:
- Date Issued: 1994
- Authors: Mkala-Pholo, Pumla Patricia
- Date: 1994
- Subjects: Environmental education -- South Africa -- Ciskei Environmental education -- Curricula -- South Africa -- Ciskei Educators -- South Africa -- Ciskei -- Attitudes Educational planning -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1692 , http://hdl.handle.net/10962/d1003575
- Description: This study was conducted to investigate perceptions of Environmental Education among senior Ciskeian educationists, and to explore the possibility of implementing Environmental Education in school and college curricula in the Ciskei region. Data was collected from interviews with a sample of senior Ciskeian educationists, then analysed and assessed. Corroborating information was obtained from attendance at several regional workshops organised by the Environmental Education Policy Initiative. The data indicated a sound general awareness of environmental problems in Ciskei and a belief in Environmental Education as a means toward their solution. Although the interviewees' understanding of Environmental Education was imperfect, there was broad support for its aims and principles. Since the study was motivated by concern about the implementation of Environmental Education in Ciskei, the results obtained were encouraging.
- Full Text:
- Date Issued: 1994
Tangentially symplectic foliations
- Authors: Remsing, Claudiu Cristian
- Date: 1994
- Subjects: Geometry Problems, exercises, etc Geometry, Differential Symplectic manifolds Poisson manifolds Foliations (Mathematics)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5419 , http://hdl.handle.net/10962/d1005233
- Description: This thesis is concerned principally with tangential geometry and the applications of these concepts to tangentially symplectic foliations. The subject of tangential geometry is still at an elementary stage. The author here systematises current concepts and results and extends them, leading to the definition of vertical connections and vertical G-structures. Tangentially symplectic foliations are then characterised in terms of vertical symplectic forms. Some significant particular cases are discussed.
- Full Text:
- Date Issued: 1994
- Authors: Remsing, Claudiu Cristian
- Date: 1994
- Subjects: Geometry Problems, exercises, etc Geometry, Differential Symplectic manifolds Poisson manifolds Foliations (Mathematics)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5419 , http://hdl.handle.net/10962/d1005233
- Description: This thesis is concerned principally with tangential geometry and the applications of these concepts to tangentially symplectic foliations. The subject of tangential geometry is still at an elementary stage. The author here systematises current concepts and results and extends them, leading to the definition of vertical connections and vertical G-structures. Tangentially symplectic foliations are then characterised in terms of vertical symplectic forms. Some significant particular cases are discussed.
- Full Text:
- Date Issued: 1994
An investigation into the need for environmental information in South Africa: a case study of the Enviro Facts Project
- Authors: Paxton, Linda Janet
- Date: 1994
- Subjects: Enviro facts project Environmental education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1611 , http://hdl.handle.net/10962/d1003493
- Description: Growing awareness of the environmental risks associated with modernity has contributed to an increasing demand for information about the environment. Conservation and other environmental organisations receive many such requests for information. The research reported here was motivated first, by the view that these requests presented an opportunity for environmental education, and second, by a concern that this potential was not being realised. The research question was thus "How can environmental education be supported by optimally responding to requests for environmental information?" It is argued that social change is the raison d' etre of environmental education as a response to environmental risks. Further, it is proposed that this might be best achieved through an approach described here as socially critical environmental education. The study comprised an historical review of the Enviro Facts Project, a recent attempt to meet the need for environmental information; a questionnaire survey; interviews; and workshops. Results were collected from 115 questionnaire responses; 23 telephone interviews and nine face-to-face interviews; and six workshops. The research design was participative. It aimed to answer the research question through co-developing practical solutions with participants. Further, it endeavoured to be of practical relevance to those participants. Conclusions are drawn as to how the research question might be answered. Recommendations are made as follows. Responses to environmental information requests might best support socially critical environmental education through an approach characterised by: * a recognition of the importance of responding optimally to environmental information requests, as well as a recognition of existing structures and resource materials with which to respond; * the mobilisation of those structures and resource materials through, for example, the effective marketing and distribution of resource materials; informed and focused networking to make existing resources and capacities more accessible; and the effective use of libraries to provide environmental information; * the enhancement of the capacities of local sources of environmental information. The findings of this study could usefully inform both resource development in environmental education, and those who in their line of work respond to requests for environmental information.
- Full Text:
- Date Issued: 1994
- Authors: Paxton, Linda Janet
- Date: 1994
- Subjects: Enviro facts project Environmental education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1611 , http://hdl.handle.net/10962/d1003493
- Description: Growing awareness of the environmental risks associated with modernity has contributed to an increasing demand for information about the environment. Conservation and other environmental organisations receive many such requests for information. The research reported here was motivated first, by the view that these requests presented an opportunity for environmental education, and second, by a concern that this potential was not being realised. The research question was thus "How can environmental education be supported by optimally responding to requests for environmental information?" It is argued that social change is the raison d' etre of environmental education as a response to environmental risks. Further, it is proposed that this might be best achieved through an approach described here as socially critical environmental education. The study comprised an historical review of the Enviro Facts Project, a recent attempt to meet the need for environmental information; a questionnaire survey; interviews; and workshops. Results were collected from 115 questionnaire responses; 23 telephone interviews and nine face-to-face interviews; and six workshops. The research design was participative. It aimed to answer the research question through co-developing practical solutions with participants. Further, it endeavoured to be of practical relevance to those participants. Conclusions are drawn as to how the research question might be answered. Recommendations are made as follows. Responses to environmental information requests might best support socially critical environmental education through an approach characterised by: * a recognition of the importance of responding optimally to environmental information requests, as well as a recognition of existing structures and resource materials with which to respond; * the mobilisation of those structures and resource materials through, for example, the effective marketing and distribution of resource materials; informed and focused networking to make existing resources and capacities more accessible; and the effective use of libraries to provide environmental information; * the enhancement of the capacities of local sources of environmental information. The findings of this study could usefully inform both resource development in environmental education, and those who in their line of work respond to requests for environmental information.
- Full Text:
- Date Issued: 1994