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
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
The porphyry copper system and the precious metal-gold potential
- Authors: Gendall, Ian Richard
- Date: 1994
- Subjects: Copper ores , Porphyry , Gold ores -- Geology , Prospecting
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4992 , http://hdl.handle.net/10962/d1005604 , Copper ores , Porphyry , Gold ores -- Geology , Prospecting
- Description: It has been established that porphyry copper/copper-gold deposits have formed from I Ma to 2 Ga ago. Generally, they are related to the Mesozoic-Cenozoic interval with few reported occurrences from the Palaeozoic or Precambrian. A reason cited is the erosion of these deposits which are often related to convergent plate margins and orogenic belts. Observations of the alteration and mineralisation within and around porphyry copper/copper-gold systems have been included in numerous idealised models. These alteration and mineralisation patterns are dependent on the phases of intrusion, the tectonic setting and rock type, depth of emplacement and relationship to coeval volcanics, physiochemical conditions operative within and surrounding the intrusive and many other mechanical and geochemical conditions. Island arc and cratonic arc/margin deposits are generally considered to be richer in gold than their molybdenum-rich, intra-cratonic counterparts. Metal zonation may occur around these copper/copper-gold deposits, e.g. copper in the core moving out to silver, lead, zinc and gold. This zonation is not always present and gold may occur in the core, intermediate or distal zones. Examples of gold-rich porphyry deposits from British Columbia, Chile and the SW Pacific Island regions suggest gold is closely associated with the potassic-rich zones. Generally these gold-rich zones have greater than 2% magnetite and a high oxygen fugacity is considered to be an important control for gold deposition. High Cl contents within the magma are necessary for gold mobility within the host intrusive centres. Beyond this zone HS₂ becomes an important transporting ligand. Exploration for porphyry copper-gold deposits includes an integrated geological, geophysical and geochemical approach. Petrographic work through to Landsat imagery may be used to determine the chemical conditions of the system, ore association, favourable structural zones and alteration patterns, in order to focus exploration activities.
- Full Text:
- Date Issued: 1994
- Authors: Gendall, Ian Richard
- Date: 1994
- Subjects: Copper ores , Porphyry , Gold ores -- Geology , Prospecting
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4992 , http://hdl.handle.net/10962/d1005604 , Copper ores , Porphyry , Gold ores -- Geology , Prospecting
- Description: It has been established that porphyry copper/copper-gold deposits have formed from I Ma to 2 Ga ago. Generally, they are related to the Mesozoic-Cenozoic interval with few reported occurrences from the Palaeozoic or Precambrian. A reason cited is the erosion of these deposits which are often related to convergent plate margins and orogenic belts. Observations of the alteration and mineralisation within and around porphyry copper/copper-gold systems have been included in numerous idealised models. These alteration and mineralisation patterns are dependent on the phases of intrusion, the tectonic setting and rock type, depth of emplacement and relationship to coeval volcanics, physiochemical conditions operative within and surrounding the intrusive and many other mechanical and geochemical conditions. Island arc and cratonic arc/margin deposits are generally considered to be richer in gold than their molybdenum-rich, intra-cratonic counterparts. Metal zonation may occur around these copper/copper-gold deposits, e.g. copper in the core moving out to silver, lead, zinc and gold. This zonation is not always present and gold may occur in the core, intermediate or distal zones. Examples of gold-rich porphyry deposits from British Columbia, Chile and the SW Pacific Island regions suggest gold is closely associated with the potassic-rich zones. Generally these gold-rich zones have greater than 2% magnetite and a high oxygen fugacity is considered to be an important control for gold deposition. High Cl contents within the magma are necessary for gold mobility within the host intrusive centres. Beyond this zone HS₂ becomes an important transporting ligand. Exploration for porphyry copper-gold deposits includes an integrated geological, geophysical and geochemical approach. Petrographic work through to Landsat imagery may be used to determine the chemical conditions of the system, ore association, favourable structural zones and alteration patterns, in order to focus exploration activities.
- Full Text:
- Date Issued: 1994
Synthesis and conformational studies of indolizines
- Authors: George, Rosemary
- Date: 1994
- Subjects: Indole alkaloids -- Research , Organic compounds -- Synthesis , Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4367 , http://hdl.handle.net/10962/d1005032 , Indole alkaloids -- Research , Organic compounds -- Synthesis , Chemistry, Organic
- Description: The present investigation has involved a kinetic and mechanistic study of the thermal cyclization of 3-acetoxy-3-(2-pyridyl)-2-methylenepropanoate esters and related compounds to 2-substituted indolizines. Substrates for the kinetic study were prepared via the Baylis-Hillmann reaction of pyridine-2-carboxaldehydes with acrylate esters, acrylonitrile and methyl vinyl ketone. The resulting hydroxy compounds were then acetylated to afford the acetoxy derivatives, thermal cyclization of which gave the corresponding 2-substituted indolizines. The cyclization reactions was followed using 'H NMR spectroscopy and were shown to follow firstorder kinetics. The influence of the various substituents on the observed first-order rate constants has been examined and variable temperature studies have permitted evaluation of activation parameters for the formation of methyl indolizine-2-carboxylate and ethyl indolizine-2-carboxylate. An alternative route to 2-substituted indolizines via halogenated derivatives was explored and several halogenated 2-pyridyl derivatives were synthesised and their thermal cyclization to indolizines was attempted. Novel 5-methylindolizine-2-carboxamides were prepared as part of this investigation and dynamic NMR spectroscopy was used to study internal rotation about the amide N-CO bond in these compounds.
- Full Text:
- Date Issued: 1994
- Authors: George, Rosemary
- Date: 1994
- Subjects: Indole alkaloids -- Research , Organic compounds -- Synthesis , Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4367 , http://hdl.handle.net/10962/d1005032 , Indole alkaloids -- Research , Organic compounds -- Synthesis , Chemistry, Organic
- Description: The present investigation has involved a kinetic and mechanistic study of the thermal cyclization of 3-acetoxy-3-(2-pyridyl)-2-methylenepropanoate esters and related compounds to 2-substituted indolizines. Substrates for the kinetic study were prepared via the Baylis-Hillmann reaction of pyridine-2-carboxaldehydes with acrylate esters, acrylonitrile and methyl vinyl ketone. The resulting hydroxy compounds were then acetylated to afford the acetoxy derivatives, thermal cyclization of which gave the corresponding 2-substituted indolizines. The cyclization reactions was followed using 'H NMR spectroscopy and were shown to follow firstorder kinetics. The influence of the various substituents on the observed first-order rate constants has been examined and variable temperature studies have permitted evaluation of activation parameters for the formation of methyl indolizine-2-carboxylate and ethyl indolizine-2-carboxylate. An alternative route to 2-substituted indolizines via halogenated derivatives was explored and several halogenated 2-pyridyl derivatives were synthesised and their thermal cyclization to indolizines was attempted. Novel 5-methylindolizine-2-carboxamides were prepared as part of this investigation and dynamic NMR spectroscopy was used to study internal rotation about the amide N-CO bond in these compounds.
- Full Text:
- Date Issued: 1994
A process for the detanning of chrome leather wastes utilising tannery effluents
- Authors: Glaum, Deanne Melanie
- Date: 1994
- Subjects: Tanneries -- Waste disposal , Recycling (Waste, etc.) , Leather
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4029 , http://hdl.handle.net/10962/d1004089 , Tanneries -- Waste disposal , Recycling (Waste, etc.) , Leather
- Description: The considerable volume of chromium-bearing wastes generated during the process of leather tanning, exacerbated by the potential for trivalent chromium in the wastes to be oxidised to the toxic hexavalent state, has created a major waste disposal dilemma for the tanning industry. While methods are available for the safe and effective treatment of residual chrome-tanning liquors, little has been done to address the issue of the chrome-bearing solid wastes. Given the increasingly stringent environmental compliance standards facing tanneries, unless an appropriate treatment process is developed in the immediate future, the continued use of chromium as a tanning agent could be compromised. Recent investigations have demonstrated the potential of heated alkaline conditions for dechroming these solid wastes. This study expanded upon these considerations and examined the feasibility of utilising the highly alkaline tannery waste effluents as cost-effective, substitute alkaline media. The three effluents considered in this study, classed as lime sulphide liquors, were shown to be capable of dechroming wet blue shavings, with resultant separation of the solid wastes into a protein and a concentrated chromium product. The solubilised protein product contained low chromium concentrations which comply with legal discharge limits. The precipitated chromium product offers opportunity for reutilisation in the tannery. A novel industrial-scale treatment process, based on these investigations, indicated the process to be capable of treating the quantity of shavings produced on a daily basis by a medium to large scale tannery. Application of this method for the dechroming of other chrome-tanned solid wastes was also shown to be feasible.
- Full Text:
- Date Issued: 1994
- Authors: Glaum, Deanne Melanie
- Date: 1994
- Subjects: Tanneries -- Waste disposal , Recycling (Waste, etc.) , Leather
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4029 , http://hdl.handle.net/10962/d1004089 , Tanneries -- Waste disposal , Recycling (Waste, etc.) , Leather
- Description: The considerable volume of chromium-bearing wastes generated during the process of leather tanning, exacerbated by the potential for trivalent chromium in the wastes to be oxidised to the toxic hexavalent state, has created a major waste disposal dilemma for the tanning industry. While methods are available for the safe and effective treatment of residual chrome-tanning liquors, little has been done to address the issue of the chrome-bearing solid wastes. Given the increasingly stringent environmental compliance standards facing tanneries, unless an appropriate treatment process is developed in the immediate future, the continued use of chromium as a tanning agent could be compromised. Recent investigations have demonstrated the potential of heated alkaline conditions for dechroming these solid wastes. This study expanded upon these considerations and examined the feasibility of utilising the highly alkaline tannery waste effluents as cost-effective, substitute alkaline media. The three effluents considered in this study, classed as lime sulphide liquors, were shown to be capable of dechroming wet blue shavings, with resultant separation of the solid wastes into a protein and a concentrated chromium product. The solubilised protein product contained low chromium concentrations which comply with legal discharge limits. The precipitated chromium product offers opportunity for reutilisation in the tannery. A novel industrial-scale treatment process, based on these investigations, indicated the process to be capable of treating the quantity of shavings produced on a daily basis by a medium to large scale tannery. Application of this method for the dechroming of other chrome-tanned solid wastes was also shown to be feasible.
- Full Text:
- Date Issued: 1994
Records of the inquest into the murder of Matthew Goniwe, Sparrow Mkonto, Fort Calata and Sicelo Mhlauli near Port Elizabeth on 27 June 1985
- Goniwe Inquest, Du Plessis, Lourens, Van Rensburg, Janse, South African Police, South Africa
- Authors: Goniwe Inquest , Du Plessis, Lourens , Van Rensburg, Janse , South African Police , South Africa
- Date: 1993-1994 , 1994
- Subjects: Goniwe, Matthew 1946-1985 , Calata, Fort -1985 , Mkonto, Sparrow -1985 , Mhlauli, Sicelo -1985 , South Africa South African Defence Force , South African Police , Violent deaths South Africa , Inquests South Africa , Colonel Du Plessis, Lourens SADF , General Van der Westhuizen, C P SADF
- Language: English , Afrikaans
- Type: legal case and case notes , text
- Identifier: http://hdl.handle.net/10962/165353 , vital:41236 , Rhodes University, Cory Library for Humanities Research Cory Library Manuscript Collection MS 18 905
- Description: Heads of Argument presented by the South African Defence Force, Col. Lourens du Plessis, the South African Police, the Acting Attorney-General of the Eastern Cape and General Janse van Rensburg, 1993-1994.
- Full Text:
- Date Issued: 1993-1994
- Date Issued: 1994
- Authors: Goniwe Inquest , Du Plessis, Lourens , Van Rensburg, Janse , South African Police , South Africa
- Date: 1993-1994 , 1994
- Subjects: Goniwe, Matthew 1946-1985 , Calata, Fort -1985 , Mkonto, Sparrow -1985 , Mhlauli, Sicelo -1985 , South Africa South African Defence Force , South African Police , Violent deaths South Africa , Inquests South Africa , Colonel Du Plessis, Lourens SADF , General Van der Westhuizen, C P SADF
- Language: English , Afrikaans
- Type: legal case and case notes , text
- Identifier: http://hdl.handle.net/10962/165353 , vital:41236 , Rhodes University, Cory Library for Humanities Research Cory Library Manuscript Collection MS 18 905
- Description: Heads of Argument presented by the South African Defence Force, Col. Lourens du Plessis, the South African Police, the Acting Attorney-General of the Eastern Cape and General Janse van Rensburg, 1993-1994.
- Full Text:
- Date Issued: 1993-1994
- Date Issued: 1994
Motion arrested : body politics and the struggle for a physical theatre
- Authors: Gordon, G E
- Date: 1994
- Subjects: Movement (Acting) , Experimental drama
- Language: English
- Type: Text
- Identifier: vital:571 , http://hdl.handle.net/10962/d1005946
- Description: [From the text]: Physical theatre does have a political agenda but it is not to provide a counter argument in terms of the body/mind divide. It utilises this encompassing approach to argue for the legitimacy and potential of the body and to counteract the argument for the supremacy of the mind over the body. The body is mobilised as a source of power to question conventional views on race, gender, sexual stereotyping and sexuality. This new "physicality" should not be viewed as a negation of the word, the text or the rational, but should be seen rather as an integration of the physical with the vocal, mental and emotional resources of the performer.
- Full Text:
- Date Issued: 1994
- Authors: Gordon, G E
- Date: 1994
- Subjects: Movement (Acting) , Experimental drama
- Language: English
- Type: Text
- Identifier: vital:571 , http://hdl.handle.net/10962/d1005946
- Description: [From the text]: Physical theatre does have a political agenda but it is not to provide a counter argument in terms of the body/mind divide. It utilises this encompassing approach to argue for the legitimacy and potential of the body and to counteract the argument for the supremacy of the mind over the body. The body is mobilised as a source of power to question conventional views on race, gender, sexual stereotyping and sexuality. This new "physicality" should not be viewed as a negation of the word, the text or the rational, but should be seen rather as an integration of the physical with the vocal, mental and emotional resources of the performer.
- Full Text:
- Date Issued: 1994
The need for a multicultural approach to mathematics curriculum design for the senior secondary school phase: a case study conducted at the Woolhope Secondary School, Port Elizabeth
- Authors: Govender, Vasuthavan Gopaul
- Date: 1994
- Subjects: Mathematics -- Curricula -- South Africa -- Case studies Multicultural education -- South Africa -- Case studies Education, Secondary -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1676 , http://hdl.handle.net/10962/d1003559
- Description: Multicultural countries such as England have recognised the need to multiculturalise their mathematics curricula to cater for the needs of all ethnic/cultural groups, to encourage racial harmony and have pupils of a specific culture learn about, and accord respect to, another culture (Duncan, 1986;Dyson, 1986; Gilbert, 1984). However, in South Africa, a multicultural country with its large Black majority, such an approach has not been given the necessary attention. Laridon (1990) has criticised the way in which curriculum development in mathematics is conducted in South Africa. He describes it as a "top-down" approach and based on input from non-representative samples of teachers and not taking into account the needs of all cultural groups in South Africa. He criticises the manner in which topics are added to or removed from the syllabus and calls this "syllabus tinkering". With a number of, mostly English medium, schools opening their doors to all races, it is possible that certain cultural groups are at a disadvantage when compared with others if modifications to the syllabus, to accommodate their needs, are not made. This study is a small scale case-study, conducted at Woolhope Secondary, a predominantly Indian school, but with a significant number of Black pupils (approximately 25%). The study focusses on the need for a multicultural approach to mathematics curriculum design. The views of the senior mathematics pupils and mathematics teachers are considered in this regard, and together with the relevant literature, broad guidelines for a multicultural mathematics curriculum design in South Africa are suggested.
- Full Text:
- Date Issued: 1994
- Authors: Govender, Vasuthavan Gopaul
- Date: 1994
- Subjects: Mathematics -- Curricula -- South Africa -- Case studies Multicultural education -- South Africa -- Case studies Education, Secondary -- Research -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1676 , http://hdl.handle.net/10962/d1003559
- Description: Multicultural countries such as England have recognised the need to multiculturalise their mathematics curricula to cater for the needs of all ethnic/cultural groups, to encourage racial harmony and have pupils of a specific culture learn about, and accord respect to, another culture (Duncan, 1986;Dyson, 1986; Gilbert, 1984). However, in South Africa, a multicultural country with its large Black majority, such an approach has not been given the necessary attention. Laridon (1990) has criticised the way in which curriculum development in mathematics is conducted in South Africa. He describes it as a "top-down" approach and based on input from non-representative samples of teachers and not taking into account the needs of all cultural groups in South Africa. He criticises the manner in which topics are added to or removed from the syllabus and calls this "syllabus tinkering". With a number of, mostly English medium, schools opening their doors to all races, it is possible that certain cultural groups are at a disadvantage when compared with others if modifications to the syllabus, to accommodate their needs, are not made. This study is a small scale case-study, conducted at Woolhope Secondary, a predominantly Indian school, but with a significant number of Black pupils (approximately 25%). The study focusses on the need for a multicultural approach to mathematics curriculum design. The views of the senior mathematics pupils and mathematics teachers are considered in this regard, and together with the relevant literature, broad guidelines for a multicultural mathematics curriculum design in South Africa are suggested.
- Full Text:
- Date Issued: 1994
The effects of particle precipitation on the ionosphere in the South Atlantic Anomaly Region
- Authors: Haggard, Raymond
- Date: 1994
- Subjects: Precipitation (Chemistry) Ionosphere Ionospheric electron density
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5463 , http://hdl.handle.net/10962/d1005248
- Description: The first ground based observations of aeronomic phenomena in the South Atlantic Anomaly Region are presented. These data show that enhancements in foF2 and foE can be directly attributed to precipitated electron energy fluxes in the Anomaly Region. The regular occurrence of particle induced sporadic-E ionization is also presented together with the first measurable 391.4 nm airglow radiation of about 16 R. The first comprehensive survey of energy fluxes carried by energetic particles using satellites is also presented for both daytime and nighttime as well as the seasonal fluctuations. We found that the nocturnally precipitated electron energy fluxes varied between 1 x 10⁻⁴ and 38 x 10⁻⁴ erg cm²s⁻¹, depending upon magnetic activity and season, whereas the daytime precipitated electron energy fluxes tended to vary between 1 x 10⁻³ and 8 x 10⁻³ erg cm⁻²s⁻¹, with a tendency to decrease during magnetically active periods. Electron density and temperature contours as well as NO⁺ and 0⁺ ions contours for nighttime are also presented. The main conclusion of the study is that precipitating electrons provide a significant and sometimes dominant source of ionization in the ionosphere over the South Atlantic Anomaly Region.
- Full Text:
- Date Issued: 1994
- Authors: Haggard, Raymond
- Date: 1994
- Subjects: Precipitation (Chemistry) Ionosphere Ionospheric electron density
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5463 , http://hdl.handle.net/10962/d1005248
- Description: The first ground based observations of aeronomic phenomena in the South Atlantic Anomaly Region are presented. These data show that enhancements in foF2 and foE can be directly attributed to precipitated electron energy fluxes in the Anomaly Region. The regular occurrence of particle induced sporadic-E ionization is also presented together with the first measurable 391.4 nm airglow radiation of about 16 R. The first comprehensive survey of energy fluxes carried by energetic particles using satellites is also presented for both daytime and nighttime as well as the seasonal fluctuations. We found that the nocturnally precipitated electron energy fluxes varied between 1 x 10⁻⁴ and 38 x 10⁻⁴ erg cm²s⁻¹, depending upon magnetic activity and season, whereas the daytime precipitated electron energy fluxes tended to vary between 1 x 10⁻³ and 8 x 10⁻³ erg cm⁻²s⁻¹, with a tendency to decrease during magnetically active periods. Electron density and temperature contours as well as NO⁺ and 0⁺ ions contours for nighttime are also presented. The main conclusion of the study is that precipitating electrons provide a significant and sometimes dominant source of ionization in the ionosphere over the South Atlantic Anomaly Region.
- Full Text:
- Date Issued: 1994
The selection and use of natural and synthetic membranes for in vitro diffusion experiments
- Haigh, John M, Smith, Eric W
- Authors: Haigh, John M , Smith, Eric W
- Date: 1994
- Language: English
- Type: text , Article
- Identifier: vital:6379 , http://hdl.handle.net/10962/d1006297
- Description: The following membranes are discussed: human skin; animal models (including mouse, hairless mouse, rat, guinea pig, rabbit, monkey, pig, shed snake skin, egg-shell membrane, and synthetic stratum corneum); and synthetic membranes (including cellulose media, filter membranes, and synthetic polymers). Membrane integrity and diffusive characteristics are also considered.
- Full Text:
- Date Issued: 1994
- Authors: Haigh, John M , Smith, Eric W
- Date: 1994
- Language: English
- Type: text , Article
- Identifier: vital:6379 , http://hdl.handle.net/10962/d1006297
- Description: The following membranes are discussed: human skin; animal models (including mouse, hairless mouse, rat, guinea pig, rabbit, monkey, pig, shed snake skin, egg-shell membrane, and synthetic stratum corneum); and synthetic membranes (including cellulose media, filter membranes, and synthetic polymers). Membrane integrity and diffusive characteristics are also considered.
- Full Text:
- Date Issued: 1994
The South African lobby in America: the battle over sanctions
- Authors: Harning, Jeannie
- Date: 1994
- Subjects: Lobbying -- South Africa , Lobbying -- United States , Economic sanctions, American -- South Africa , South Africa -- Foreign relations -- United States , United States -- Foreign relations -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2779 , http://hdl.handle.net/10962/d1002989 , Lobbying -- South Africa , Lobbying -- United States , Economic sanctions, American -- South Africa , South Africa -- Foreign relations -- United States , United States -- Foreign relations -- South Africa
- Description: The relationship between South Africa and the United States was, historically, quite mutually profitable. The South African government regarded the United States as an ally in the world and sought continued friendship with them. The United States was mildly critical of the South African system of apartheid, but they, however, viewed South Africa as an ally. During the 1980's the relationship between the two countries became strained as the anti-apartheid voices in the United States grew louder and louder. The movement sought to end the atrocities of apartheid and change American foreign policy toward South Africa. The strongest diplomatic means available to them was imposing economic sanctions on South Africa in an attempt to force political change in the country. The anti-apartheid movement lobbied extensively gaining support among the American pub1ic and eventually the U.S. Congress. The sanctions campaign culminated in the enactment of the Comprehensive Anti-Apartheid Act (CAAA) of 1986. Prior to the enactment of the CAAA the South African government and its allies launched their own campaign in an attempt to combat the imposition of sanctions. Lobbying played a key role in the process for those on both sides of the issue. For the anti- apartheid movement, lobbying was effective on the American public and the U.S Congress. For the South African government lobbying was effective on the conservative right wing and President Reagan and his administration.
- Full Text:
- Date Issued: 1994
- Authors: Harning, Jeannie
- Date: 1994
- Subjects: Lobbying -- South Africa , Lobbying -- United States , Economic sanctions, American -- South Africa , South Africa -- Foreign relations -- United States , United States -- Foreign relations -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2779 , http://hdl.handle.net/10962/d1002989 , Lobbying -- South Africa , Lobbying -- United States , Economic sanctions, American -- South Africa , South Africa -- Foreign relations -- United States , United States -- Foreign relations -- South Africa
- Description: The relationship between South Africa and the United States was, historically, quite mutually profitable. The South African government regarded the United States as an ally in the world and sought continued friendship with them. The United States was mildly critical of the South African system of apartheid, but they, however, viewed South Africa as an ally. During the 1980's the relationship between the two countries became strained as the anti-apartheid voices in the United States grew louder and louder. The movement sought to end the atrocities of apartheid and change American foreign policy toward South Africa. The strongest diplomatic means available to them was imposing economic sanctions on South Africa in an attempt to force political change in the country. The anti-apartheid movement lobbied extensively gaining support among the American pub1ic and eventually the U.S. Congress. The sanctions campaign culminated in the enactment of the Comprehensive Anti-Apartheid Act (CAAA) of 1986. Prior to the enactment of the CAAA the South African government and its allies launched their own campaign in an attempt to combat the imposition of sanctions. Lobbying played a key role in the process for those on both sides of the issue. For the anti- apartheid movement, lobbying was effective on the American public and the U.S Congress. For the South African government lobbying was effective on the conservative right wing and President Reagan and his administration.
- Full Text:
- Date Issued: 1994
A survey of the writing approaches followed by ESL teachers in Port Elizabeth secondary schools where Afrikaans is the first language
- Authors: Harran, Marcelle
- Date: 1994
- Subjects: English language -- Study and teaching -- South Africa -- Foreign speakers Written communication -- Study and teaching -- South Africa English language -- Writing
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1789 , http://hdl.handle.net/10962/d1003674
- Description: In this study an attempt is made to describe and illuminate the current approaches to ESL writing in secondary schools in the Port Elizabeth-Despatch areas where Afrikaans is the first language of the pupils. Teacher and pupil Questionnaires were used as a means of data collection through which the approaches, practices and attitudes to the teaching of ESL writing in the secondary schools in the survey area could be reviewed and assessed. The teacher Questionnaire revealed that most respondents appeared to have a limited awareness or understanding of basic composing processes, especially the role of multiple drafting and teacher intervention in the form of interactive feedback. There is also evidence that there is a limited understanding of how these activities can be effectively implemented in a classroom situation. The pupil Questionnaire was used as a means to extend the understanding of teacher approaches to ESL writing as revealed in the teacher Questionnaire, to enable comparisons to be made and to evaluate the writing approaches currently practised in the ESL classroom. Many of the observations revealed in the teacher Questionnaire were echoed in the analysis of the pupil Questionnaire, especially the limited roles of planning and feedback, treatment of error, attitude to writing and the limited improvement in writing as pupils progress through the secondary school. The analysis also revealed that pupils were reluctant to expose, or share their work with audiences, were pre-occupied with error and viewed the teacher as grade-giver, grammarian and topic-provider. Topic selection was also revealed as a factor which influenced the pupils' negative or indifferent attitudes to writing. Although the process approach was considered a traditional approach to writing by 1986, the analysis and review of the Questionnaire data has revealed that a fair assessment of the state of ESL writing in the survey schools would place the current writing approaches in the traditional product- centred, form-dominated, teacher-centred mould. For this position to change, research pedagogy will need to become part of teacher training and the classroom so that there can be greater teacher awareness and understanding of composing processes and their implementation in the classroom. This is necessary, because research findings have revealed that a genuine orientation to a process approach and the application of composing stategies followed by good writers will result in improved writing progress and pupils having a more positive attitude to writing.
- Full Text:
- Date Issued: 1994
- Authors: Harran, Marcelle
- Date: 1994
- Subjects: English language -- Study and teaching -- South Africa -- Foreign speakers Written communication -- Study and teaching -- South Africa English language -- Writing
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1789 , http://hdl.handle.net/10962/d1003674
- Description: In this study an attempt is made to describe and illuminate the current approaches to ESL writing in secondary schools in the Port Elizabeth-Despatch areas where Afrikaans is the first language of the pupils. Teacher and pupil Questionnaires were used as a means of data collection through which the approaches, practices and attitudes to the teaching of ESL writing in the secondary schools in the survey area could be reviewed and assessed. The teacher Questionnaire revealed that most respondents appeared to have a limited awareness or understanding of basic composing processes, especially the role of multiple drafting and teacher intervention in the form of interactive feedback. There is also evidence that there is a limited understanding of how these activities can be effectively implemented in a classroom situation. The pupil Questionnaire was used as a means to extend the understanding of teacher approaches to ESL writing as revealed in the teacher Questionnaire, to enable comparisons to be made and to evaluate the writing approaches currently practised in the ESL classroom. Many of the observations revealed in the teacher Questionnaire were echoed in the analysis of the pupil Questionnaire, especially the limited roles of planning and feedback, treatment of error, attitude to writing and the limited improvement in writing as pupils progress through the secondary school. The analysis also revealed that pupils were reluctant to expose, or share their work with audiences, were pre-occupied with error and viewed the teacher as grade-giver, grammarian and topic-provider. Topic selection was also revealed as a factor which influenced the pupils' negative or indifferent attitudes to writing. Although the process approach was considered a traditional approach to writing by 1986, the analysis and review of the Questionnaire data has revealed that a fair assessment of the state of ESL writing in the survey schools would place the current writing approaches in the traditional product- centred, form-dominated, teacher-centred mould. For this position to change, research pedagogy will need to become part of teacher training and the classroom so that there can be greater teacher awareness and understanding of composing processes and their implementation in the classroom. This is necessary, because research findings have revealed that a genuine orientation to a process approach and the application of composing stategies followed by good writers will result in improved writing progress and pupils having a more positive attitude to writing.
- Full Text:
- Date Issued: 1994
Perceptions of primary school teachers towards the South African Museum as an environmental education resource
- Authors: Harrison, Jo-Anne Elizabeth
- Date: 1994
- Subjects: Elementary school teachers -- South Africa -- Attitudes South African Museum Environmental education -- South Africa Environmental education -- Curricula -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1694 , http://hdl.handle.net/10962/d1003577
- Description: This study examines the perceptions of a small group of primary school teachers from Gugulethu in Cape Town, of the various exhibitions and education services currently offered at the South African Museum. Their perceptions of proposed services are also examined in order to find out which of these proposals, as well as existing services, best meet the needs expressed by this group of teachers. An attempt was also made to determine their level of understanding of environmental education and awareness of environmental issues. This study suggested the need for greater emphasis to be placed on the 'hands-on' components of the Museum's education programmes. The need for syllabus related and enriching educational programmes and resource materials was also identified. In this regard, the exhibits perceived to be of greatest benefit to the pupils were those relating either to the syllabus or their culture, whilst exhibits seen to be 'out of the pupils' experience' (eg. Fossils) were perceived as unimportant. The teachers also epressed a strong desire for training sessions to be held at the Museum that would help them improve their knowledge of the displays and programmes. It was found that the teachers understanding of environmental education ranged from syllabus-related definitions to more holistic views. The environmental issues perceived to be of greatest importance were mainly social issues such as poverty, violence, child abuse and street children as well as water pollution and cruelty to animals. The production of posters and resource materials, drama, story-telling and programmes for parents were seen to be among the choices most favoured for the Museum to adopt in promoting environmental awareness in the community.
- Full Text:
- Date Issued: 1994
- Authors: Harrison, Jo-Anne Elizabeth
- Date: 1994
- Subjects: Elementary school teachers -- South Africa -- Attitudes South African Museum Environmental education -- South Africa Environmental education -- Curricula -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1694 , http://hdl.handle.net/10962/d1003577
- Description: This study examines the perceptions of a small group of primary school teachers from Gugulethu in Cape Town, of the various exhibitions and education services currently offered at the South African Museum. Their perceptions of proposed services are also examined in order to find out which of these proposals, as well as existing services, best meet the needs expressed by this group of teachers. An attempt was also made to determine their level of understanding of environmental education and awareness of environmental issues. This study suggested the need for greater emphasis to be placed on the 'hands-on' components of the Museum's education programmes. The need for syllabus related and enriching educational programmes and resource materials was also identified. In this regard, the exhibits perceived to be of greatest benefit to the pupils were those relating either to the syllabus or their culture, whilst exhibits seen to be 'out of the pupils' experience' (eg. Fossils) were perceived as unimportant. The teachers also epressed a strong desire for training sessions to be held at the Museum that would help them improve their knowledge of the displays and programmes. It was found that the teachers understanding of environmental education ranged from syllabus-related definitions to more holistic views. The environmental issues perceived to be of greatest importance were mainly social issues such as poverty, violence, child abuse and street children as well as water pollution and cruelty to animals. The production of posters and resource materials, drama, story-telling and programmes for parents were seen to be among the choices most favoured for the Museum to adopt in promoting environmental awareness in the community.
- Full Text:
- Date Issued: 1994
Ecology of the ichthyofauna in three temporarily open/closed estuaries on the Natal coast
- Authors: Harrison, Trevor D
- Date: 1994
- Subjects: Estuarine ecology -- South Africa -- KwaZulu-Natal , Estuarine animals -- South Africa -- Swartkops River Estuary , Fishes -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5269 , http://hdl.handle.net/10962/d1005113 , Estuarine ecology -- South Africa -- KwaZulu-Natal , Estuarine animals -- South Africa -- Swartkops River Estuary , Fishes -- South Africa -- KwaZulu-Natal
- Description: The ichthyofauna of three small Natal estuaries, the Mhlanga, Damba and Zotsha was sampled over a period of two years. A total of 68 kinds of fishes representing 24 families, 39 genera and 56 species were captured during this study. Forty seven kinds of fishes were recorded in the Mhlanga of which Gilchristella aestuaria,Oreochromis mossambicus, Valamugil cunnesius, Valamugil sp. and juvenile mugilids numerically dominated. In terms of biomass, O. mossambicus, V. cunnesius, Liza alata, Myxus capensis and Mugil cephalus dominated the ichthyofauna of the Mhlanga. In the Damba, 24 kinds of fishes were recorded. The most abundant fishes captured were Glossogobius callidus, M. capensis and O. mossambicus. M. capensis, M. cephalus, O. mossambicus and G. callidus dominated the fish biomass captured in the Damba. A total of 56 kinds of fishes were recorded in the Zotsha during this study. The ichthyofauna of the Zotsha was numerically dominated by juvenile mugilids, G. aestuaria, O. mossambicus, Rhabdosargus holubi, Terapon jarbua, Ambassis productus and G. callidus. The species which dominated the fish biomass in the Zotsha were O. mossambicus, L. alata, Valamugil robustus, Valamugil buchanani, M. capensis, M. cephalus and V. cunnesius. Classifying the species captured according to whether they were resident estuarine species, freshwater species, estuarine-dependent marine species and marine species revealed that the first three groups were all well represented in the systems. The only system in which marine species made any significant contribution to the ichthyofauna was the Zotsha. Oreochromis mossambicus was the dominant freshwater species in all three estuaries during this study. Gilchristella aestuaria and Glossogobius callidus were the principal estuarine species in the Mhlanga and the Damba respectively. Both G. aestuaria and G. callidus were the dominant estuarine species captured in the Zotsha. The principal estuarine-dependent marine fishes captured in the Mhlanga were V. cunnesius, Valamugil sp., juvenile mugilids, M. capensis, M. cephalus and L. alata. In the Damba, M. capensis and M. cephalus were the dominant estuarine-dependent marine species and in the Zotsha juvenile mugilids, R. holubi, T. jarbua, A . productus, M. capensis, V. cunnesius, V. robustus, M. cephalus and L. alata predominated. The results of this study indicate that the estuaries are dominated at different periods by different assemblages of fishes. This is linked to the spawning and migration patterns of the various species as well as the hydrological regime of each estuary. During the winter these systems are normally closed with relatively deep waters and high food resource and habitat availability. Freshwater and estuarine species mainly inhabit the upper reaches of the systems while estuarine-dependent marine species mainly occupy the middle and lower reaches and dominate the fish community. When these systems open with the onset of the spring/summer rains, adult and sub-adult estuarine-dependent marine species emigrate to the marine environment and juveniles begin recruiting into the systems. Spring is also the peak breeding period of resident estuarine and freshwater species, resulting in an increase in the contribution of these fishes to the overall population during this period. When closed estuaries open many of them drain and this results in the fishes concentrating in the lower reaches of the system where moderate water depths are present, thus further contributing to an increase in the proportion of freshwater and estuarine species in this region. The breaching of closed estuaries also results in a slump in food resources and habitat availability. Competition and possible increased vulnerability to avian predation (due to the shallow nature of the systems), may contribute to a decrease in the proportion of estuarine and freshwater species in summer. The prolonged spawning and recruitment of 0+ juveniles of estuarine-dependent marine species results in an increase in the proportion of these fishes present in the estuaries during summer. In autumn, these systems normally close, water levels rise and available food resources and habitat increase. This allows the redistribution of freshwater and estuarine species upstream, leaving estuarine-dependent marine species to dominate the middle and lower reaches. Although temporarily open/closed estuaries along the Natal coast may not be as diverse as permanently open estuaries in terms of their ichthyofauna, their importance must not be underestimated since by providing a continuous sequence of sheltered habitats along the coast they may contribute significantly to the viability of estuarine-dependent marine fish stocks.
- Full Text:
- Date Issued: 1994
- Authors: Harrison, Trevor D
- Date: 1994
- Subjects: Estuarine ecology -- South Africa -- KwaZulu-Natal , Estuarine animals -- South Africa -- Swartkops River Estuary , Fishes -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5269 , http://hdl.handle.net/10962/d1005113 , Estuarine ecology -- South Africa -- KwaZulu-Natal , Estuarine animals -- South Africa -- Swartkops River Estuary , Fishes -- South Africa -- KwaZulu-Natal
- Description: The ichthyofauna of three small Natal estuaries, the Mhlanga, Damba and Zotsha was sampled over a period of two years. A total of 68 kinds of fishes representing 24 families, 39 genera and 56 species were captured during this study. Forty seven kinds of fishes were recorded in the Mhlanga of which Gilchristella aestuaria,Oreochromis mossambicus, Valamugil cunnesius, Valamugil sp. and juvenile mugilids numerically dominated. In terms of biomass, O. mossambicus, V. cunnesius, Liza alata, Myxus capensis and Mugil cephalus dominated the ichthyofauna of the Mhlanga. In the Damba, 24 kinds of fishes were recorded. The most abundant fishes captured were Glossogobius callidus, M. capensis and O. mossambicus. M. capensis, M. cephalus, O. mossambicus and G. callidus dominated the fish biomass captured in the Damba. A total of 56 kinds of fishes were recorded in the Zotsha during this study. The ichthyofauna of the Zotsha was numerically dominated by juvenile mugilids, G. aestuaria, O. mossambicus, Rhabdosargus holubi, Terapon jarbua, Ambassis productus and G. callidus. The species which dominated the fish biomass in the Zotsha were O. mossambicus, L. alata, Valamugil robustus, Valamugil buchanani, M. capensis, M. cephalus and V. cunnesius. Classifying the species captured according to whether they were resident estuarine species, freshwater species, estuarine-dependent marine species and marine species revealed that the first three groups were all well represented in the systems. The only system in which marine species made any significant contribution to the ichthyofauna was the Zotsha. Oreochromis mossambicus was the dominant freshwater species in all three estuaries during this study. Gilchristella aestuaria and Glossogobius callidus were the principal estuarine species in the Mhlanga and the Damba respectively. Both G. aestuaria and G. callidus were the dominant estuarine species captured in the Zotsha. The principal estuarine-dependent marine fishes captured in the Mhlanga were V. cunnesius, Valamugil sp., juvenile mugilids, M. capensis, M. cephalus and L. alata. In the Damba, M. capensis and M. cephalus were the dominant estuarine-dependent marine species and in the Zotsha juvenile mugilids, R. holubi, T. jarbua, A . productus, M. capensis, V. cunnesius, V. robustus, M. cephalus and L. alata predominated. The results of this study indicate that the estuaries are dominated at different periods by different assemblages of fishes. This is linked to the spawning and migration patterns of the various species as well as the hydrological regime of each estuary. During the winter these systems are normally closed with relatively deep waters and high food resource and habitat availability. Freshwater and estuarine species mainly inhabit the upper reaches of the systems while estuarine-dependent marine species mainly occupy the middle and lower reaches and dominate the fish community. When these systems open with the onset of the spring/summer rains, adult and sub-adult estuarine-dependent marine species emigrate to the marine environment and juveniles begin recruiting into the systems. Spring is also the peak breeding period of resident estuarine and freshwater species, resulting in an increase in the contribution of these fishes to the overall population during this period. When closed estuaries open many of them drain and this results in the fishes concentrating in the lower reaches of the system where moderate water depths are present, thus further contributing to an increase in the proportion of freshwater and estuarine species in this region. The breaching of closed estuaries also results in a slump in food resources and habitat availability. Competition and possible increased vulnerability to avian predation (due to the shallow nature of the systems), may contribute to a decrease in the proportion of estuarine and freshwater species in summer. The prolonged spawning and recruitment of 0+ juveniles of estuarine-dependent marine species results in an increase in the proportion of these fishes present in the estuaries during summer. In autumn, these systems normally close, water levels rise and available food resources and habitat increase. This allows the redistribution of freshwater and estuarine species upstream, leaving estuarine-dependent marine species to dominate the middle and lower reaches. Although temporarily open/closed estuaries along the Natal coast may not be as diverse as permanently open estuaries in terms of their ichthyofauna, their importance must not be underestimated since by providing a continuous sequence of sheltered habitats along the coast they may contribute significantly to the viability of estuarine-dependent marine fish stocks.
- Full Text:
- Date Issued: 1994
Influence of blue/green versus red and white light sources on human dark adaptation and other selected visual functions
- Authors: Hendrikse, Egbert Johannes
- Date: 1994
- Subjects: Light -- Physiological effect Lighting Vision -- Research Night vision Visual acuity Color -- Physiological effect Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5146 , http://hdl.handle.net/10962/d1009497
- Description: Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
- Full Text:
- Date Issued: 1994
- Authors: Hendrikse, Egbert Johannes
- Date: 1994
- Subjects: Light -- Physiological effect Lighting Vision -- Research Night vision Visual acuity Color -- Physiological effect Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5146 , http://hdl.handle.net/10962/d1009497
- Description: Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
- Full Text:
- Date Issued: 1994
A strategy for promoting the use of computers across the curriculum at primary school level: a case study
- Authors: Heukelman, Delene
- Date: 1994
- Subjects: Education, Elementary -- Computer programs Computers and children Education, Elementary -- Data processing Computer-assisted instruction
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1774 , http://hdl.handle.net/10962/d1003659
- Description: A growing number of primary schools are acquiring computers, mainly through parent funding. The study concerns the promotion of computer use across the curriculum in primary schools. Teachers need to be trained in the use of computers as a teaching aid in different subjects. A study comparing two periods of training was undertaken. Two model C primary schools, administered by the Department of Education and Culture, with similar profiles of educational computer use, were selected for the purpose. A training course consisting of five sections, where the use of the word processor, spreadsheet and database, both as personal tools and as teaching aids were introduced, was offered. Care was taken to select topics from current syllabi and to demonstrate how these topics could be presented and enhanced by using the computer. The training was presented at school A over a period of 8 months and at school B over a period of 5 weeks. The supporting material and contents of the course were the same for both groups. A comparison between the effectiveness of the two training regimes was made. The researcher's initial perceptions of the teachers' initial low level of computer literacy were confirmed by a questionnaire, responded to by each participant. It would seem that the shorter raining period was more effective in raising the level of computer literacy and that if the training period was longer, the contact time should be increased to maintain support. Neither training period resulted in a significant increase in computer use, either as a personal tool or as a teaching aid. The failure to do so may be ascribed to a number of influences, one of which is the teaching style of individual teachers. Changing the teaching style of an experienced teacher takes time and more effort than was available for either training period.
- Full Text:
- Date Issued: 1994
- Authors: Heukelman, Delene
- Date: 1994
- Subjects: Education, Elementary -- Computer programs Computers and children Education, Elementary -- Data processing Computer-assisted instruction
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1774 , http://hdl.handle.net/10962/d1003659
- Description: A growing number of primary schools are acquiring computers, mainly through parent funding. The study concerns the promotion of computer use across the curriculum in primary schools. Teachers need to be trained in the use of computers as a teaching aid in different subjects. A study comparing two periods of training was undertaken. Two model C primary schools, administered by the Department of Education and Culture, with similar profiles of educational computer use, were selected for the purpose. A training course consisting of five sections, where the use of the word processor, spreadsheet and database, both as personal tools and as teaching aids were introduced, was offered. Care was taken to select topics from current syllabi and to demonstrate how these topics could be presented and enhanced by using the computer. The training was presented at school A over a period of 8 months and at school B over a period of 5 weeks. The supporting material and contents of the course were the same for both groups. A comparison between the effectiveness of the two training regimes was made. The researcher's initial perceptions of the teachers' initial low level of computer literacy were confirmed by a questionnaire, responded to by each participant. It would seem that the shorter raining period was more effective in raising the level of computer literacy and that if the training period was longer, the contact time should be increased to maintain support. Neither training period resulted in a significant increase in computer use, either as a personal tool or as a teaching aid. The failure to do so may be ascribed to a number of influences, one of which is the teaching style of individual teachers. Changing the teaching style of an experienced teacher takes time and more effort than was available for either training period.
- Full Text:
- Date Issued: 1994
An investigation into twentieth century flute trios with special reference to representative works by Goossens, Sil'vansky, Raphael, Damase, Marx and Crumb
- Authors: Heunis, Daniela
- Date: 1994
- Subjects: Goossens, Eugene, 1893-1962 Silʹvanskíí, Nikolǎi Iosifovich, 1915-1985 Raphael, Günter, 1903-1960 Damase, Jean-Michel, 1928- Crumb, George Woodwind trios (Flutes (3))
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2641 , http://hdl.handle.net/10962/d1002306
- Description: This thesis ventures into the world of twentieth century chamber music, specifically the trios written for flute, cello and piano. The first chapter discusses the history of the trio, tracing its development from the trio sonata of the Baroque Period to the accompanied sonatas and specifically the sonatas with flute and cello obbligato. Following the unpopularity of the genre throughout the Romantic period, its greater prominence in the Twentieth century is discussed, mentioning specific groups through whom the repertoire has been extended. Forty trios are grouped according to compositional styles. Six trios, each representing an example of a specific style period, have been selected for more detailed discussion, with particular reference to the various ways in which a sense of unity is achieved in each trio. The English composer Eugene Goossens uses impressionistic images, whole tone and chromatic scale patterns and other motifs to unify his trio: "Five Impressions of a Holiday". Nikolay Iosifovich Sil'vansky's "The Hedgehog and the Nightingale" is based on a Russian tale by Juri Jarmicha and uses a narrator. The three characters are represented by specific motivic and / or thematic material which is used throughout the trio. Günter Raphael's Trio-Suite op 44 is the only cyclic work unifying the two outer movements, without repeating any additional motivic material. Jean-Michel Damase condenses some of the material introduced in the opening Prelude in both the two Largo's and the two Arias in his "Sonate en Concert" of 1950. Karl Julius Marx builds his entire "Trio op 61" on a flexible six-note motif. Various movements in the trio" Vox Ba1aenae" by the American George Crumb are 1inked through the use of motives and characteristic instrumental colour. A comprehensive list of 180 twentieth century trios has been compiled, including details of dedications, commissions and first performances. 163 composers from twenty countries, are represented.
- Full Text:
- Date Issued: 1994
- Authors: Heunis, Daniela
- Date: 1994
- Subjects: Goossens, Eugene, 1893-1962 Silʹvanskíí, Nikolǎi Iosifovich, 1915-1985 Raphael, Günter, 1903-1960 Damase, Jean-Michel, 1928- Crumb, George Woodwind trios (Flutes (3))
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2641 , http://hdl.handle.net/10962/d1002306
- Description: This thesis ventures into the world of twentieth century chamber music, specifically the trios written for flute, cello and piano. The first chapter discusses the history of the trio, tracing its development from the trio sonata of the Baroque Period to the accompanied sonatas and specifically the sonatas with flute and cello obbligato. Following the unpopularity of the genre throughout the Romantic period, its greater prominence in the Twentieth century is discussed, mentioning specific groups through whom the repertoire has been extended. Forty trios are grouped according to compositional styles. Six trios, each representing an example of a specific style period, have been selected for more detailed discussion, with particular reference to the various ways in which a sense of unity is achieved in each trio. The English composer Eugene Goossens uses impressionistic images, whole tone and chromatic scale patterns and other motifs to unify his trio: "Five Impressions of a Holiday". Nikolay Iosifovich Sil'vansky's "The Hedgehog and the Nightingale" is based on a Russian tale by Juri Jarmicha and uses a narrator. The three characters are represented by specific motivic and / or thematic material which is used throughout the trio. Günter Raphael's Trio-Suite op 44 is the only cyclic work unifying the two outer movements, without repeating any additional motivic material. Jean-Michel Damase condenses some of the material introduced in the opening Prelude in both the two Largo's and the two Arias in his "Sonate en Concert" of 1950. Karl Julius Marx builds his entire "Trio op 61" on a flexible six-note motif. Various movements in the trio" Vox Ba1aenae" by the American George Crumb are 1inked through the use of motives and characteristic instrumental colour. A comprehensive list of 180 twentieth century trios has been compiled, including details of dedications, commissions and first performances. 163 composers from twenty countries, are represented.
- Full Text:
- Date Issued: 1994
The challenge of trade union rights in Africa
- ICFTU
- Authors: ICFTU
- Date: 1994
- Subjects: International Confederation of Free Trade Unions (ICFTU)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/153951 , vital:39540
- Description: A purely academic observer would probably find significant cause for optimism about the evolution of the trade union rights situation in Africa in the 1990’s, and about the observance of human rights more generally. The continent has lived under the sign of democratization since the beginning of the decade, and the extent of political transformation has been unprecedented and astonishing. Since 1989, at least 25 African nations have adopted entirely new constitutions or major constitutional reforms. To them may be added those countries - for so long an isolated minority - which already operated pluralist democratic systems and those, more numerous, which are still engaged in processes of transition and reform.
- Full Text:
- Date Issued: 1994
- Authors: ICFTU
- Date: 1994
- Subjects: International Confederation of Free Trade Unions (ICFTU)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/153951 , vital:39540
- Description: A purely academic observer would probably find significant cause for optimism about the evolution of the trade union rights situation in Africa in the 1990’s, and about the observance of human rights more generally. The continent has lived under the sign of democratization since the beginning of the decade, and the extent of political transformation has been unprecedented and astonishing. Since 1989, at least 25 African nations have adopted entirely new constitutions or major constitutional reforms. To them may be added those countries - for so long an isolated minority - which already operated pluralist democratic systems and those, more numerous, which are still engaged in processes of transition and reform.
- 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
The design, implementation and evaluation of an English language development component within a Grahamstown community project
- Authors: Jefferay, Charlotte Ruth
- Date: 1994
- Subjects: Grahamstown Tertiary Education Bridging Project , English language -- Study and teaching -- South Africa -- Foreign speakers , English language -- Writing -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2351 , http://hdl.handle.net/10962/d1002633 , Grahamstown Tertiary Education Bridging Project , English language -- Study and teaching -- South Africa -- Foreign speakers , English language -- Writing -- Study and teaching -- South Africa -- Foreign speakers
- Description: The Grahamstown Tertiary Education Bridging Project (GRATEP) was formed in 1991 by a group of post-matriculants from Grahamstown who had not been accepted into any tertiary institution for 1991. The overall aim of GRATEP was to prepare these students for tertiary education. The Academic Skills Programme at Rhodes University offered a programme in English Language Development. The present study aimed to research the design, implementation and evaluation of the GRATEP English Language Development programme which was implemented from May through to October 1991. A multimethod approach has been used to assess the progress made by the students in terms of developing communicative competence in English and to evaluate the course itself. The data included writing samples, questionnaires, exercises in hierarchical organization, a clozetest, comments made by the students and the participant observers. The programme appeared to have been most effective in terms of building confidence, developing academic skills and encouraging the students to take greater responsibility for their own learning. Statistical comparisons of the first and final writing samples revealed no overall significant improvement in communicative competence in English. However, comparisons of the scores in the categories and sub-categories of communicative competence revealed that students had improved in their ability to structure and organize their writing. The research raised questions about the design, implementation and assessment of non-formal language courses of this kind and made suggestions for improvement and further research.
- Full Text:
- Date Issued: 1994
- Authors: Jefferay, Charlotte Ruth
- Date: 1994
- Subjects: Grahamstown Tertiary Education Bridging Project , English language -- Study and teaching -- South Africa -- Foreign speakers , English language -- Writing -- Study and teaching -- South Africa -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2351 , http://hdl.handle.net/10962/d1002633 , Grahamstown Tertiary Education Bridging Project , English language -- Study and teaching -- South Africa -- Foreign speakers , English language -- Writing -- Study and teaching -- South Africa -- Foreign speakers
- Description: The Grahamstown Tertiary Education Bridging Project (GRATEP) was formed in 1991 by a group of post-matriculants from Grahamstown who had not been accepted into any tertiary institution for 1991. The overall aim of GRATEP was to prepare these students for tertiary education. The Academic Skills Programme at Rhodes University offered a programme in English Language Development. The present study aimed to research the design, implementation and evaluation of the GRATEP English Language Development programme which was implemented from May through to October 1991. A multimethod approach has been used to assess the progress made by the students in terms of developing communicative competence in English and to evaluate the course itself. The data included writing samples, questionnaires, exercises in hierarchical organization, a clozetest, comments made by the students and the participant observers. The programme appeared to have been most effective in terms of building confidence, developing academic skills and encouraging the students to take greater responsibility for their own learning. Statistical comparisons of the first and final writing samples revealed no overall significant improvement in communicative competence in English. However, comparisons of the scores in the categories and sub-categories of communicative competence revealed that students had improved in their ability to structure and organize their writing. The research raised questions about the design, implementation and assessment of non-formal language courses of this kind and made suggestions for improvement and further research.
- Full Text:
- Date Issued: 1994