The "Civilised Labour Policy" and the private sector : the operation of the South African Wage Act, 1925-1937
- Authors: Phillips, Ian Munro
- Date: 1984
- Subjects: Wages -- Government policy -- South Africa. Labour policy -- South Africa Discrimination in employment -- South Africa Wages -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2594 , http://hdl.handle.net/10962/d1007354
- Description: The early history of South African industrial development has been approached from essentially two angles. One body of thought has concentrated on the adverse effect colour bars have had on the development of South Africa. It is argued that racial discrimination in industry originated from the racial prejudice of white workers and from state intervention in the economy. Opposed to that view is the interpretation that the colour bar originated out of the specific character and subsequent development of South African capitalism. This study approaches the debates and arguments through an analysis of the Wage Act of 1925. The industrial relations system which operates in South Africa has its origins in the legislation of the 1920s. It is based on the Industrial Conciliation Act of 1924 and the Wage Act of 1925. Very few systematic analyses of the Wage Act have been produced hitherto. Most commentators have focussed on single aspects of the Act, but very few have attempted an examination of the operation of the Wage Board which was established by the Act. The Wage Board was instituted as an element to promote the civilised labour policy in the private sector. Whereas the Industrial Conciliation Act operated to protect organised labour, the Wage Act concentrated on unorganised trades and sections of trades. Although empowered to investigate conditions in the mining industry, the Wage Board was never used to regulate wages in that industry under the Wage Act due to opposition from the industry. It was concerned solely with secondary industrial and manufacturing establishments because agriculture and domestic service were excluded from the Wage Act. The Wage Act was based on the principal of compulsory regulation. Determinations in terms of the Board's recommendations were binding on employees and employers alike. Complex procedures hampered the activity of the Board until 1930 when the Act was amended and simplified. The Board faced a great deal of opposition from manufacturers in its early years. But a cautious approach and the gradual implementation of determinations ensured that employers opposition soon changed to support when it became clear the Board was not an arbitrary one. The Board had to take a number of strict considerations into account. It could not recommend wages if its recommendation would affect the particular trade concerned adversely. It concerned itself with the promotion of efficiency in business, production costs, consumerism , the wasteful employment of labour, the length of the working day and the productivity of employees. As such it was used as a means to assist the necessary rationalisation and reorganisation of South African industry. It could not recommend wages without the Minister's express instructions if all the employees covered by a reference could not receive a civilised wage . Civilised wages were classified as wages at which employees could enjoy white standards of living. This clause effectively introduced a colour bar into wage determinations. It operated before 1930 to buttress Industrial Council Agreements to prevent the displacement of whites by Africans at lower rates. The Wage Board also considered investigations from unskilled, African workers. The Board was not permitted by law to discriminate against people of colour. Apart from the potential colour bar of wage regulation in general in South Africa, the Board was instructed in 1930 to refrain from issuing recommendations for African workers. Regulations were also altered to exclude Africans. The Wage Act declined in importance after the Great Depression as white workers were drawn closer to the wider-reaching Industrial Conciliation Act. The need to regulate African wages and to control African labour became more evident during the period of economic expansion in the 1930s. The Act was replaced in 1937 and the restrictions formerly placed on Africans were removed. The workforce had finally been separated with the provision of different industrial relations appartuses." "...Every industrial and commercial centre in England now possesses a working class divided into two hostile camps, English proletarians and Irish proletarians. The ordinary English worker hates the Irish worker as a competitor who lowers his standard of life. In relation to the Irish worker he feels himself a member of the ruling nation and so turns himself into a tool of the aristocrats and capitalists of his country against Ireland, thus strengthening their domination over himself. He cherishes religious, social, and national prejudices against the Irish worker. His attitude towards him is much the same as that of the 'poor whites' to the 'niggers' in the former slave states of the USA. The Irishman pays him back with interest in his own money. He sees in the English worker at once the accomplice and the stupid tool of the English rule in Ireland. This antagonism is artificially kept alive and intensified by the press, the pulpit, the comic papers, in short, by all the means at the disposal of the ruling classes. This antagonism is the secret of the impotence of the English working class, despite its organisation. It is the secret by which the capitalist class maintains its power. And that class is fully aware of it." Marx to Siegfried Meyer and August Vogt April 9 1870 Marx and Engels Ireland and the Irish Question.
- Full Text:
- Date Issued: 1984
- Authors: Phillips, Ian Munro
- Date: 1984
- Subjects: Wages -- Government policy -- South Africa. Labour policy -- South Africa Discrimination in employment -- South Africa Wages -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2594 , http://hdl.handle.net/10962/d1007354
- Description: The early history of South African industrial development has been approached from essentially two angles. One body of thought has concentrated on the adverse effect colour bars have had on the development of South Africa. It is argued that racial discrimination in industry originated from the racial prejudice of white workers and from state intervention in the economy. Opposed to that view is the interpretation that the colour bar originated out of the specific character and subsequent development of South African capitalism. This study approaches the debates and arguments through an analysis of the Wage Act of 1925. The industrial relations system which operates in South Africa has its origins in the legislation of the 1920s. It is based on the Industrial Conciliation Act of 1924 and the Wage Act of 1925. Very few systematic analyses of the Wage Act have been produced hitherto. Most commentators have focussed on single aspects of the Act, but very few have attempted an examination of the operation of the Wage Board which was established by the Act. The Wage Board was instituted as an element to promote the civilised labour policy in the private sector. Whereas the Industrial Conciliation Act operated to protect organised labour, the Wage Act concentrated on unorganised trades and sections of trades. Although empowered to investigate conditions in the mining industry, the Wage Board was never used to regulate wages in that industry under the Wage Act due to opposition from the industry. It was concerned solely with secondary industrial and manufacturing establishments because agriculture and domestic service were excluded from the Wage Act. The Wage Act was based on the principal of compulsory regulation. Determinations in terms of the Board's recommendations were binding on employees and employers alike. Complex procedures hampered the activity of the Board until 1930 when the Act was amended and simplified. The Board faced a great deal of opposition from manufacturers in its early years. But a cautious approach and the gradual implementation of determinations ensured that employers opposition soon changed to support when it became clear the Board was not an arbitrary one. The Board had to take a number of strict considerations into account. It could not recommend wages if its recommendation would affect the particular trade concerned adversely. It concerned itself with the promotion of efficiency in business, production costs, consumerism , the wasteful employment of labour, the length of the working day and the productivity of employees. As such it was used as a means to assist the necessary rationalisation and reorganisation of South African industry. It could not recommend wages without the Minister's express instructions if all the employees covered by a reference could not receive a civilised wage . Civilised wages were classified as wages at which employees could enjoy white standards of living. This clause effectively introduced a colour bar into wage determinations. It operated before 1930 to buttress Industrial Council Agreements to prevent the displacement of whites by Africans at lower rates. The Wage Board also considered investigations from unskilled, African workers. The Board was not permitted by law to discriminate against people of colour. Apart from the potential colour bar of wage regulation in general in South Africa, the Board was instructed in 1930 to refrain from issuing recommendations for African workers. Regulations were also altered to exclude Africans. The Wage Act declined in importance after the Great Depression as white workers were drawn closer to the wider-reaching Industrial Conciliation Act. The need to regulate African wages and to control African labour became more evident during the period of economic expansion in the 1930s. The Act was replaced in 1937 and the restrictions formerly placed on Africans were removed. The workforce had finally been separated with the provision of different industrial relations appartuses." "...Every industrial and commercial centre in England now possesses a working class divided into two hostile camps, English proletarians and Irish proletarians. The ordinary English worker hates the Irish worker as a competitor who lowers his standard of life. In relation to the Irish worker he feels himself a member of the ruling nation and so turns himself into a tool of the aristocrats and capitalists of his country against Ireland, thus strengthening their domination over himself. He cherishes religious, social, and national prejudices against the Irish worker. His attitude towards him is much the same as that of the 'poor whites' to the 'niggers' in the former slave states of the USA. The Irishman pays him back with interest in his own money. He sees in the English worker at once the accomplice and the stupid tool of the English rule in Ireland. This antagonism is artificially kept alive and intensified by the press, the pulpit, the comic papers, in short, by all the means at the disposal of the ruling classes. This antagonism is the secret of the impotence of the English working class, despite its organisation. It is the secret by which the capitalist class maintains its power. And that class is fully aware of it." Marx to Siegfried Meyer and August Vogt April 9 1870 Marx and Engels Ireland and the Irish Question.
- Full Text:
- Date Issued: 1984
The career maturity of the gifted and talented pupil
- Authors: Rainier, Markseller Garrett
- Date: 1984
- Subjects: Gifted children--Psychology Counseling in vocational education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1371 , http://hdl.handle.net/10962/d1001437
- Description: In 1980 the cape Education Department launched a Gifted and Talented programme in some schools which was intended to enrich the educational experience of the more able pupils. Numerous studies have shown these pupils to have a higher level of career maturity than non-gifted pupils, but the studies have also shown that these pupils face unique career- development problems. Gifted and Talented pupils constitute an important source of manpower and their potential contribution to the total society is great. Consequently they are in need of effective career guidance to help them overcome their unique problems and realize their potential. This study set out to discover if the career maturity of a group of Standard 9 Gifted and Talented pupils, identified according to the original Cape Education Department criteria, is indeed higher than that of their peers and to make recommendations for facilitating career education among these pupils. Contrary to expectations the Gifted and Talented pupils did not show significantly higher levels of career maturity than their peers, as measured on the Attitude Scale of Crites ' Career Maturity Inventory. Compared with the American norms , the scores obtained by the research population were unfavourable. The validity of the I .Q. scores used and the criteria for identification of Gifted and Talented pupils are seen as questionable which could have led to an inaccurate grouping of the pupils as Gifted and Talented or non- gifted. Recommendations are made for a basic career education programme for all pupils which would include periods of active work experience. Recommendations for additional career education for those currently classified as Gifted and Talented pupils are also made, so as to allow these pupils additional time for self- development, decisionmaking and dealing with their unique life situation
- Full Text:
- Date Issued: 1984
- Authors: Rainier, Markseller Garrett
- Date: 1984
- Subjects: Gifted children--Psychology Counseling in vocational education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1371 , http://hdl.handle.net/10962/d1001437
- Description: In 1980 the cape Education Department launched a Gifted and Talented programme in some schools which was intended to enrich the educational experience of the more able pupils. Numerous studies have shown these pupils to have a higher level of career maturity than non-gifted pupils, but the studies have also shown that these pupils face unique career- development problems. Gifted and Talented pupils constitute an important source of manpower and their potential contribution to the total society is great. Consequently they are in need of effective career guidance to help them overcome their unique problems and realize their potential. This study set out to discover if the career maturity of a group of Standard 9 Gifted and Talented pupils, identified according to the original Cape Education Department criteria, is indeed higher than that of their peers and to make recommendations for facilitating career education among these pupils. Contrary to expectations the Gifted and Talented pupils did not show significantly higher levels of career maturity than their peers, as measured on the Attitude Scale of Crites ' Career Maturity Inventory. Compared with the American norms , the scores obtained by the research population were unfavourable. The validity of the I .Q. scores used and the criteria for identification of Gifted and Talented pupils are seen as questionable which could have led to an inaccurate grouping of the pupils as Gifted and Talented or non- gifted. Recommendations are made for a basic career education programme for all pupils which would include periods of active work experience. Recommendations for additional career education for those currently classified as Gifted and Talented pupils are also made, so as to allow these pupils additional time for self- development, decisionmaking and dealing with their unique life situation
- Full Text:
- Date Issued: 1984
The chemistry and petrogenesis of igneous rocks of the Karoo central area, southern Africa
- Eales, Hugh V, Marsh, Julian S
- Authors: Eales, Hugh V , Marsh, Julian S
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133934 , vital:37042 , https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6519911
- Description: Outcrops of the Jurassic Karoo basalts and dolerites in central South Africa are remnants of an intracratonic continental igneous suite whose volume probably once exceeded 1.5 x 106 km³. Basic rocks with 6-8% MgO, 50-55% Si02 and Mg-number = 53-67 are overwhelmingly dominant in the Central area suite. Application of discriminant analysis to a data set of major and trace element analyses of the basic rocks confirms field and petrographic evidence that a number of compositionally distinct basalt magma types exist in the Central area.
- Full Text:
- Date Issued: 1984
- Authors: Eales, Hugh V , Marsh, Julian S
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133934 , vital:37042 , https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6519911
- Description: Outcrops of the Jurassic Karoo basalts and dolerites in central South Africa are remnants of an intracratonic continental igneous suite whose volume probably once exceeded 1.5 x 106 km³. Basic rocks with 6-8% MgO, 50-55% Si02 and Mg-number = 53-67 are overwhelmingly dominant in the Central area suite. Application of discriminant analysis to a data set of major and trace element analyses of the basic rocks confirms field and petrographic evidence that a number of compositionally distinct basalt magma types exist in the Central area.
- Full Text:
- Date Issued: 1984
The community education centre : a factor in the formula for the provision of education in South Africa
- Authors: Heath, Thomas Brian Charles
- Date: 1984
- Subjects: Community education -- South Africa Fundamental education -- South Africa Adult education -- South Africa Education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1908 , http://hdl.handle.net/10962/d1006915
- Full Text:
- Date Issued: 1984
- Authors: Heath, Thomas Brian Charles
- Date: 1984
- Subjects: Community education -- South Africa Fundamental education -- South Africa Adult education -- South Africa Education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1908 , http://hdl.handle.net/10962/d1006915
- Full Text:
- Date Issued: 1984
The demography, breeding biology and management of two mullet species (Pisces : Mugilidae) in the Eastern Cape, South Africa
- Authors: Bok, Anton
- Date: 1984
- Subjects: Fishes -- South Africa -- Eastern Cape Mullidae -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5213 , http://hdl.handle.net/10962/d1004931
- Description: Aspects of the life history of Myxus capensis which were likely to be most affected by man-induced habitat changes, were studied in the eastern Cape. Myxus capensis was found to be specialized for a catadromous life history. The fry migrate into freshwater reaches of rivers within a few months of being spawned at sea and return to an estuarine or marine environment when maximum size has been attained and large energy reserves necessary for spawning have been accumulated. Myxus capensis penetrates considerable distances up eastern Cape rivers and although present in the upper reaches of some estuaries, is only common in freshwater-dominated systems. Myxus capensis has adapted its life history style in a number of ways to overcome the constraints associated with the spatial separation of the freshwater feeding areas and the marine spawning grounds in a region prone to droughts and erratic river flow. Research on the more estuarine-dependent Mugil cephalus, which is also found in the freshwater reaches of eastern Cape rivers, enabled useful comparisons to be drawn. As the latter species is not dependent on a freshwater phase in its life cycle, it is subject to different selection pressures. This comparative approach gave insights into the adaptive significance of the life history tactics of Myxus capensis. Myxus capensis displays a number of life history tactics characteristic of migratory fish species which are thought to increase population fecundity by increasing the number of large females and hence maximizing egg production. These include a sex ratio in favour of females, faster female growth, females remaining longer in the freshwater feeding areas and reaching a larger ultimate size. Possible adaptations to the periodic isolation of the feeding and spawning areas include: (i) the development of ripe gonads only in estuarine or marine areas when access to the spawning grounds is ensured; (ii) year-round spawning and hence recruitment which enables the erratic floods to be used at any time for downriver spawning migrations and reduces the chances of total recruitment failure due to short-term adverse environmental conditions and (iii) a relatively wide range of size and age at first (and final) sexual maturity (2+ to 5+ years); this tends to ensure successful reproduction and recruitment in spite of a series of poor years, as well as dampen population fluctuations after long periods of isolation in fresh water. The dependence of Myxus capensis on the freshwater reaches of eastern Cape rivers makes this species vulnerable to man-induced habitat changes. The erection of barriers to migration has cut off large stretches of suitable habitat and almost completely eliminated Myxus capensis from certain rivers. This detrimental effect has been largely responsible for the recent inclusion of this species on the Red Data list of endangered fish species in South Africa. This study demonstrated the considerable fisheries potential of both mullet species and this should ensure that their conservation and wise utilization be given high priority. Management proposals include: (i) the netting and lifting of Myxus capensis over barriers to migration; (ii) the construction of fish ladders when feasible and (iii) the artificial propagation of this species to enable large-scale stockings of existing man-made impoundments as well as natural habitats to be carried out. It is predicted that the life history characteristics of Myxus capensis, which evolved in response to an erratic freshwater environment, should ensure that when man-induced habitat changes are rectified, this species will again flourish in eastern Cape rivers.
- Full Text:
- Date Issued: 1984
- Authors: Bok, Anton
- Date: 1984
- Subjects: Fishes -- South Africa -- Eastern Cape Mullidae -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5213 , http://hdl.handle.net/10962/d1004931
- Description: Aspects of the life history of Myxus capensis which were likely to be most affected by man-induced habitat changes, were studied in the eastern Cape. Myxus capensis was found to be specialized for a catadromous life history. The fry migrate into freshwater reaches of rivers within a few months of being spawned at sea and return to an estuarine or marine environment when maximum size has been attained and large energy reserves necessary for spawning have been accumulated. Myxus capensis penetrates considerable distances up eastern Cape rivers and although present in the upper reaches of some estuaries, is only common in freshwater-dominated systems. Myxus capensis has adapted its life history style in a number of ways to overcome the constraints associated with the spatial separation of the freshwater feeding areas and the marine spawning grounds in a region prone to droughts and erratic river flow. Research on the more estuarine-dependent Mugil cephalus, which is also found in the freshwater reaches of eastern Cape rivers, enabled useful comparisons to be drawn. As the latter species is not dependent on a freshwater phase in its life cycle, it is subject to different selection pressures. This comparative approach gave insights into the adaptive significance of the life history tactics of Myxus capensis. Myxus capensis displays a number of life history tactics characteristic of migratory fish species which are thought to increase population fecundity by increasing the number of large females and hence maximizing egg production. These include a sex ratio in favour of females, faster female growth, females remaining longer in the freshwater feeding areas and reaching a larger ultimate size. Possible adaptations to the periodic isolation of the feeding and spawning areas include: (i) the development of ripe gonads only in estuarine or marine areas when access to the spawning grounds is ensured; (ii) year-round spawning and hence recruitment which enables the erratic floods to be used at any time for downriver spawning migrations and reduces the chances of total recruitment failure due to short-term adverse environmental conditions and (iii) a relatively wide range of size and age at first (and final) sexual maturity (2+ to 5+ years); this tends to ensure successful reproduction and recruitment in spite of a series of poor years, as well as dampen population fluctuations after long periods of isolation in fresh water. The dependence of Myxus capensis on the freshwater reaches of eastern Cape rivers makes this species vulnerable to man-induced habitat changes. The erection of barriers to migration has cut off large stretches of suitable habitat and almost completely eliminated Myxus capensis from certain rivers. This detrimental effect has been largely responsible for the recent inclusion of this species on the Red Data list of endangered fish species in South Africa. This study demonstrated the considerable fisheries potential of both mullet species and this should ensure that their conservation and wise utilization be given high priority. Management proposals include: (i) the netting and lifting of Myxus capensis over barriers to migration; (ii) the construction of fish ladders when feasible and (iii) the artificial propagation of this species to enable large-scale stockings of existing man-made impoundments as well as natural habitats to be carried out. It is predicted that the life history characteristics of Myxus capensis, which evolved in response to an erratic freshwater environment, should ensure that when man-induced habitat changes are rectified, this species will again flourish in eastern Cape rivers.
- Full Text:
- Date Issued: 1984
The development of an in-service training programme for mathematics teachers on the development and use of resource materials in black schools at the standard six-seven level
- Authors: Jiya, M A Yaliwe
- Date: 1984
- Subjects: Mathematics teachers -- In-service training -- South Africa Black people -- Education -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1875 , http://hdl.handle.net/10962/d1005634
- Full Text:
- Date Issued: 1984
- Authors: Jiya, M A Yaliwe
- Date: 1984
- Subjects: Mathematics teachers -- In-service training -- South Africa Black people -- Education -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1875 , http://hdl.handle.net/10962/d1005634
- Full Text:
- Date Issued: 1984
The effects of relative market share and the rate of market growth on the strategic attributes and financial performance of selected South African companies from 1977 to 1981
- Authors: Viljoen, John
- Date: 1984
- Subjects: Johannesburg Stock Exchange Boston Consulting Group Business enterprises -- Valuation -- South Africa Business enterprises -- South Africa -- Finance Business enterprises -- Economic aspects -- South Africa Stock exchanges -- South Africa Success in business Marketing research Strategic planning Business planning
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:722 , http://hdl.handle.net/10962/d1003816
- Description: This thesis analyses the effects of relative market share and the rate of market growth on the strategic characteristics and financial performance of selected companies quoted on the Johannesburg Stock Exchange over the period 1977 to 198. It is well established that business performance is partially contingent upon relative market share position and the rate of market growth. Together these variables comprise the basis of the Boston Consulting Group approach to portfolio analysis in the form of the Boston Consulting Group Growth/Share Matrix. A methodology was designed to test the validity of this matrix in measuring and predicting corporate behaviour at the business level in South Africa. Selected companies were placed into the matrix and analysed in terms of their strategic attributes (represented by selected financial ratios) and their level of performance (represented by a wide range of financial performance measures). The research findings show that relative market share and the rate of market growth have a significant impact on the strategic attributes and financial performance of South African businesses. Also, certain attributes are closely associated with particular types of performance. Therefore, given a specific performance target, management should ultimately be able to isolate and monitor the relevant strategic attributes in ensuring that the target is achieved. The analysis of contingent models of strategy is still in its infancy, but this study indicates that the field is possessed of great potential.
- Full Text:
- Date Issued: 1984
- Authors: Viljoen, John
- Date: 1984
- Subjects: Johannesburg Stock Exchange Boston Consulting Group Business enterprises -- Valuation -- South Africa Business enterprises -- South Africa -- Finance Business enterprises -- Economic aspects -- South Africa Stock exchanges -- South Africa Success in business Marketing research Strategic planning Business planning
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:722 , http://hdl.handle.net/10962/d1003816
- Description: This thesis analyses the effects of relative market share and the rate of market growth on the strategic characteristics and financial performance of selected companies quoted on the Johannesburg Stock Exchange over the period 1977 to 198. It is well established that business performance is partially contingent upon relative market share position and the rate of market growth. Together these variables comprise the basis of the Boston Consulting Group approach to portfolio analysis in the form of the Boston Consulting Group Growth/Share Matrix. A methodology was designed to test the validity of this matrix in measuring and predicting corporate behaviour at the business level in South Africa. Selected companies were placed into the matrix and analysed in terms of their strategic attributes (represented by selected financial ratios) and their level of performance (represented by a wide range of financial performance measures). The research findings show that relative market share and the rate of market growth have a significant impact on the strategic attributes and financial performance of South African businesses. Also, certain attributes are closely associated with particular types of performance. Therefore, given a specific performance target, management should ultimately be able to isolate and monitor the relevant strategic attributes in ensuring that the target is achieved. The analysis of contingent models of strategy is still in its infancy, but this study indicates that the field is possessed of great potential.
- Full Text:
- Date Issued: 1984
The evolution of heteronomous host relationships in Aphelinidaa (Hymenoptera Chalcidoidea) with special reference to the biology of Coccophagus Bartletti Annecke and Insley
- Authors: Walter, Grenville Hugh
- Date: 1984
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5620 , http://hdl.handle.net/10962/d1003746
- Description: Résumé: Heteronomous host relationships are unique to parasitoids in about 8 aphelinid genera. Males have host relationships quite distinct from those of their females. Females of ALL species are primary endoparasitoids of homopterous hosts. Males, on the other hand, may be either primary ectoparasitoids of the same host species as their conspecific females, or they may be hyperparasitic upon parasitoids within Homoptera, and some are primary endoparasitoids of moth eggs. Species in these groups are termed DIPHAGOUS PARASITOIDS, HETERONOMOUS HYPERPARASITOIDS and HETEROTROPHIC PARASITOIDS, respectively. The selective advantages proposed to explain the evolution of these unusual host relationships are examined in this thesis. The biology of a diphagous parasitoid was examined in detail because diphagous parasitism is considered the most primitive of heteronomous host relationships. Diphagous parasitism is thought to have evolved during a period when ovipositing females continuously encountered large proportions of parasitised hosts. Larval competition may have generated the selection pressures that favoured male ectoparasitism. Ectoparasitoids are known to be superior in competition against other larvae, even older ones. A series of observations was carried out on the diphagous parasitoid, Coccophagus bartletti. Information was gathered on oviposition and host-feeding behaviour, daily activity patterns, and sex ratios in the laboratory and field. This enabled the design and interpretation of a series of observations on the responses of mated C. bartletti females to already-parasitised hosts. The results indicate that competition from other parasitoids probably played no role in the evolution of diphagous host relationships. Heteronomous hyperparasitoids, thought to have evolved from diphagous parasitoids, appear to be strong competitors because their males kill other parasitoids. However, an alternative hypothesis to the competition one, and based on the present study, is presented. Implications for the generally-held view, that competition is important in moulding species' characters, are discussed.
- Full Text:
- Date Issued: 1984
- Authors: Walter, Grenville Hugh
- Date: 1984
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5620 , http://hdl.handle.net/10962/d1003746
- Description: Résumé: Heteronomous host relationships are unique to parasitoids in about 8 aphelinid genera. Males have host relationships quite distinct from those of their females. Females of ALL species are primary endoparasitoids of homopterous hosts. Males, on the other hand, may be either primary ectoparasitoids of the same host species as their conspecific females, or they may be hyperparasitic upon parasitoids within Homoptera, and some are primary endoparasitoids of moth eggs. Species in these groups are termed DIPHAGOUS PARASITOIDS, HETERONOMOUS HYPERPARASITOIDS and HETEROTROPHIC PARASITOIDS, respectively. The selective advantages proposed to explain the evolution of these unusual host relationships are examined in this thesis. The biology of a diphagous parasitoid was examined in detail because diphagous parasitism is considered the most primitive of heteronomous host relationships. Diphagous parasitism is thought to have evolved during a period when ovipositing females continuously encountered large proportions of parasitised hosts. Larval competition may have generated the selection pressures that favoured male ectoparasitism. Ectoparasitoids are known to be superior in competition against other larvae, even older ones. A series of observations was carried out on the diphagous parasitoid, Coccophagus bartletti. Information was gathered on oviposition and host-feeding behaviour, daily activity patterns, and sex ratios in the laboratory and field. This enabled the design and interpretation of a series of observations on the responses of mated C. bartletti females to already-parasitised hosts. The results indicate that competition from other parasitoids probably played no role in the evolution of diphagous host relationships. Heteronomous hyperparasitoids, thought to have evolved from diphagous parasitoids, appear to be strong competitors because their males kill other parasitoids. However, an alternative hypothesis to the competition one, and based on the present study, is presented. Implications for the generally-held view, that competition is important in moulding species' characters, are discussed.
- Full Text:
- Date Issued: 1984
The geology, mineralogy and chemistry of the Grahamstown clay deposits
- Authors: Smuts, Johann, 1951-
- Date: 1984
- Subjects: Clay minerals -- South Africa -- Grahamstown , Mineralogy -- South Africa -- Grahamstown , Geochemistry -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5080 , http://hdl.handle.net/10962/d1015969
- Description: The Grahamstown clay deposits extend in a broad belt from 26°23 to 26°50 East longitude and from 33°15 to 33°22 South latitude along two distinct geomorphological features, the Grahamstown Peneplane (650 m) and the Coastal Plain (520m). The clay deposits traverse four different lithologies including the Bokkeveld Shale, Witteberg Shale, Dwyka Tillite and Ecca Shale. The two planes invariably have a covering of silcrete which is also present over most of the clay deposits except where erosion has taken place. X-ray fluorescence analysis shows that chemically there is a fairly wide variation between and witnin the deposits. The greatest variation is in the Si0₂/Al₂0₃ ratio which appears to be controlled by the parent lithology and to some extent by the amount of leaching. K²0 shows an increase in concentration with depth and therefore indicates the limits of hydrolysis and leaching and of the clay. X-ray diffraction study shows the Peneplane and Coastal Plain deposits to be quite distinct. The Peneplane deposits consist of kaolinite, illite and quartz and the Coastal Plain deposits of kaolinite, illite, quartz and pyrophyllite. The presence of pyrophyllite is not fully understood as there is no indication of major faulting, metamorphism or pyrophyllite in the parent rock. The pyrophyllite most probably represents a transformation product of kaolinite. The kaolinite from the various deposits shows a considerable variation in crystallinity in both the X-ray diffraction traces and electron photomicrographs. The most poorly crystalline kaolinites are from the Coastal Plain deposits and the difference in crystallinity is most probably due to differences in the degree of hydrolysis and the parent rock material in the case of the tillite. Genetically all of the deposits are residual types generated by hydrolysis and subsequent leaching of micas and feldspars. The principal elements leached are silicon, iron and potassium. The hydrolysis and leaching took place over a long period of time in the flat lying areas of the Peneplane and Coastal Plain. The deposits are exploited economically and the clay is used principally in the tile, pottery and whiteware industries with some usage in the paper, refractory and brickmaking industries. The price commanded by raw kaolin is not very high and as a result the clay industry in Grahamstown is not as viable economically as it could be.
- Full Text:
- Date Issued: 1984
- Authors: Smuts, Johann, 1951-
- Date: 1984
- Subjects: Clay minerals -- South Africa -- Grahamstown , Mineralogy -- South Africa -- Grahamstown , Geochemistry -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5080 , http://hdl.handle.net/10962/d1015969
- Description: The Grahamstown clay deposits extend in a broad belt from 26°23 to 26°50 East longitude and from 33°15 to 33°22 South latitude along two distinct geomorphological features, the Grahamstown Peneplane (650 m) and the Coastal Plain (520m). The clay deposits traverse four different lithologies including the Bokkeveld Shale, Witteberg Shale, Dwyka Tillite and Ecca Shale. The two planes invariably have a covering of silcrete which is also present over most of the clay deposits except where erosion has taken place. X-ray fluorescence analysis shows that chemically there is a fairly wide variation between and witnin the deposits. The greatest variation is in the Si0₂/Al₂0₃ ratio which appears to be controlled by the parent lithology and to some extent by the amount of leaching. K²0 shows an increase in concentration with depth and therefore indicates the limits of hydrolysis and leaching and of the clay. X-ray diffraction study shows the Peneplane and Coastal Plain deposits to be quite distinct. The Peneplane deposits consist of kaolinite, illite and quartz and the Coastal Plain deposits of kaolinite, illite, quartz and pyrophyllite. The presence of pyrophyllite is not fully understood as there is no indication of major faulting, metamorphism or pyrophyllite in the parent rock. The pyrophyllite most probably represents a transformation product of kaolinite. The kaolinite from the various deposits shows a considerable variation in crystallinity in both the X-ray diffraction traces and electron photomicrographs. The most poorly crystalline kaolinites are from the Coastal Plain deposits and the difference in crystallinity is most probably due to differences in the degree of hydrolysis and the parent rock material in the case of the tillite. Genetically all of the deposits are residual types generated by hydrolysis and subsequent leaching of micas and feldspars. The principal elements leached are silicon, iron and potassium. The hydrolysis and leaching took place over a long period of time in the flat lying areas of the Peneplane and Coastal Plain. The deposits are exploited economically and the clay is used principally in the tile, pottery and whiteware industries with some usage in the paper, refractory and brickmaking industries. The price commanded by raw kaolin is not very high and as a result the clay industry in Grahamstown is not as viable economically as it could be.
- Full Text:
- Date Issued: 1984
The Hakea fruit weevil, Erytenna consputa Pascoe (Coleoptera: Curculionidae), and the biological control of Hakea sericea Schrader in South Africa
- Authors: Kluge, Robert Louis
- Date: 1984
- Subjects: Insects as biological pest control agents -- South Africa Biological pest control agents -- South Africa Beetles -- South Africa Curculionidae -- South Africa Weeds -- Biological control -- South Africa Pests -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5629 , http://hdl.handle.net/10962/d1004911
- Description: Hakea sericea is a shrub, introduced into South Africa from southern Australia, that is now invading the indigenous "fynbos" vegetation in the Cape mountains. Presently an area of 480 000 hectares is affected. One of the main factors contributing to the success of H. sericea as a weed is its copious seed production. The seeds are accumulated on the plant throughout its life-time. When the plant eventually dies, usually after a fire, the fruits dehisce and all the seeds are released within the space of a few days, resulting in seed densities of up to 7 500 seeds per m². Dense, impenetrable stands of H. sericea develop which suppress the indigenous vegetation. Apart from the labour intensive mechanical clearing of H. sericea, biological control appears to be the only other means of control. This study deals with the post-release evaluation of the effectiveness of the first successfully-established, biological control agent, the hakea fruit weevil, Erytenna consputa. Most of the damage is done by the larval stage of the weevil which attacks the young developing fruits, thereby reducing seed production.
- Full Text:
- Date Issued: 1984
- Authors: Kluge, Robert Louis
- Date: 1984
- Subjects: Insects as biological pest control agents -- South Africa Biological pest control agents -- South Africa Beetles -- South Africa Curculionidae -- South Africa Weeds -- Biological control -- South Africa Pests -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5629 , http://hdl.handle.net/10962/d1004911
- Description: Hakea sericea is a shrub, introduced into South Africa from southern Australia, that is now invading the indigenous "fynbos" vegetation in the Cape mountains. Presently an area of 480 000 hectares is affected. One of the main factors contributing to the success of H. sericea as a weed is its copious seed production. The seeds are accumulated on the plant throughout its life-time. When the plant eventually dies, usually after a fire, the fruits dehisce and all the seeds are released within the space of a few days, resulting in seed densities of up to 7 500 seeds per m². Dense, impenetrable stands of H. sericea develop which suppress the indigenous vegetation. Apart from the labour intensive mechanical clearing of H. sericea, biological control appears to be the only other means of control. This study deals with the post-release evaluation of the effectiveness of the first successfully-established, biological control agent, the hakea fruit weevil, Erytenna consputa. Most of the damage is done by the larval stage of the weevil which attacks the young developing fruits, thereby reducing seed production.
- Full Text:
- Date Issued: 1984
The historical collection, King George VI Art Gallery, Port Elizabeth
- Authors: Forster-Towne, Rosemary
- Date: 1984
- Subjects: Art collections and art museums Fine arts and History of art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2463 , http://hdl.handle.net/10962/d1008567
- Description: From Conclusion: For the sake of posterity and historical research, our need for secure origins and our appreciation of and pleasure in fine craftsmanship and art, it is important that any Art Collection, particularly an Historical one, be fully documented. All data pertaining to the pictures should be recorded from an artistic, historical and even scientific point of view and photographs should be taken of the pictures. An organized classification system, the correct registering and labeling of each picture and its accessioning and cataloguing as part of the contents of the Gallery and for visitors information, should be constantly 53 maintained and where necessary and in as many ways as possible, cross-references made so that the stored information be usable. To this end and with the growth and increasing importance being placed on Art Museums and Galleries in the community it would probably be of value to cross-reference with other similar institutions and in the respect and day and age, it is not unrealistic to propose that the King George VI Art Gallery consider a computer cataloguing system to facilitate research and complement a more simplified version for the use and guide of the general viewing public . The significance of a picture is not only its value as such, but also the information relating to it. The importance of the Historical Collection as Africana and works of art, expressive of the places, events, people and even attitudes, and as cultural and historic items, goes without saying. Without the Historical Collection of the King George VI Art Gallery, Port Elizabeth, the Eastern Cape community and South Africa too, would be the poorer. The pictures have their role to play .
- Full Text:
- Date Issued: 1984
- Authors: Forster-Towne, Rosemary
- Date: 1984
- Subjects: Art collections and art museums Fine arts and History of art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2463 , http://hdl.handle.net/10962/d1008567
- Description: From Conclusion: For the sake of posterity and historical research, our need for secure origins and our appreciation of and pleasure in fine craftsmanship and art, it is important that any Art Collection, particularly an Historical one, be fully documented. All data pertaining to the pictures should be recorded from an artistic, historical and even scientific point of view and photographs should be taken of the pictures. An organized classification system, the correct registering and labeling of each picture and its accessioning and cataloguing as part of the contents of the Gallery and for visitors information, should be constantly 53 maintained and where necessary and in as many ways as possible, cross-references made so that the stored information be usable. To this end and with the growth and increasing importance being placed on Art Museums and Galleries in the community it would probably be of value to cross-reference with other similar institutions and in the respect and day and age, it is not unrealistic to propose that the King George VI Art Gallery consider a computer cataloguing system to facilitate research and complement a more simplified version for the use and guide of the general viewing public . The significance of a picture is not only its value as such, but also the information relating to it. The importance of the Historical Collection as Africana and works of art, expressive of the places, events, people and even attitudes, and as cultural and historic items, goes without saying. Without the Historical Collection of the King George VI Art Gallery, Port Elizabeth, the Eastern Cape community and South Africa too, would be the poorer. The pictures have their role to play .
- Full Text:
- Date Issued: 1984
The hydrogeology and hydrogeochemisty of the aquifers of the Hex River Valley, Cape Province
- Authors: Rosewarne, Peter Nigel
- Date: 1984 , 2013-04-11
- Subjects: Hydrogeology , Aquifers , Water chemistry , Hydrogeology -- South Africa -- Cape Colony
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4863 , http://hdl.handle.net/10962/d1007224 , Hydrogeology , Aquifers , Water chemistry , Hydrogeology -- South Africa -- Cape Colony
- Description: The Hex River Valley is one of the main centres in South Africa for cultivation of table grapes of export quality. The vines require irrigation water, which must be low in dissolved solids. Approximately two thirds of the annual irrigation requirement is obtained from boreholes and the balance from surface water sources. During the early 1960s a deterioration in the quality of the groundwater was noticed, becoming critical in some areas, and borehole yields also declined. The main objectives of this study were therefore to obtain an understanding of the hydrogeological and hydrogeochemical processes operating in the valley to explain the derogation of the groundwater resource and enable optimum utilisation and management of the resource in the future. To achieve these objectives, field work involving exploration drilling, aquifer tests, hydrocensus, long-term monitoring of groundwater levels and surfacewater flows and extensive sampling of the ground and surface waters was carried out. Analysis of these data gave quantitative information on groundwater occurrence, aquifer hydraulic properties, groundwater recharge and storage, chemical characteristics of the ground and surfacewaters and sources of dissolved species. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1984
- Authors: Rosewarne, Peter Nigel
- Date: 1984 , 2013-04-11
- Subjects: Hydrogeology , Aquifers , Water chemistry , Hydrogeology -- South Africa -- Cape Colony
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4863 , http://hdl.handle.net/10962/d1007224 , Hydrogeology , Aquifers , Water chemistry , Hydrogeology -- South Africa -- Cape Colony
- Description: The Hex River Valley is one of the main centres in South Africa for cultivation of table grapes of export quality. The vines require irrigation water, which must be low in dissolved solids. Approximately two thirds of the annual irrigation requirement is obtained from boreholes and the balance from surface water sources. During the early 1960s a deterioration in the quality of the groundwater was noticed, becoming critical in some areas, and borehole yields also declined. The main objectives of this study were therefore to obtain an understanding of the hydrogeological and hydrogeochemical processes operating in the valley to explain the derogation of the groundwater resource and enable optimum utilisation and management of the resource in the future. To achieve these objectives, field work involving exploration drilling, aquifer tests, hydrocensus, long-term monitoring of groundwater levels and surfacewater flows and extensive sampling of the ground and surface waters was carried out. Analysis of these data gave quantitative information on groundwater occurrence, aquifer hydraulic properties, groundwater recharge and storage, chemical characteristics of the ground and surfacewaters and sources of dissolved species. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1984
The Karoo igneous province: an introduction
- Eales, Hugh V, Marsh, Julian S, Cox, K G
- Authors: Eales, Hugh V , Marsh, Julian S , Cox, K G
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133945 , vital:37043 , http://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6519910
- Description: The Karoo rocks are amongst the earliest manifestations of igneous activity accompanying the break-up of Gondwanaland during the early Mesozoic. Remnants of the once extensive lava sequence and the associated dolerite sills are found throughout southern Africa south of latitude 150S, the present outcrop being ca. 140,000 km². The main peak of volcanic activity is dated at about 190 m.y. and is probably coincident with the earliest stages of the opening of the Indian Ocean by the separation of Antarctica from southern Africa.
- Full Text:
- Date Issued: 1984
- Authors: Eales, Hugh V , Marsh, Julian S , Cox, K G
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133945 , vital:37043 , http://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6519910
- Description: The Karoo rocks are amongst the earliest manifestations of igneous activity accompanying the break-up of Gondwanaland during the early Mesozoic. Remnants of the once extensive lava sequence and the associated dolerite sills are found throughout southern Africa south of latitude 150S, the present outcrop being ca. 140,000 km². The main peak of volcanic activity is dated at about 190 m.y. and is probably coincident with the earliest stages of the opening of the Indian Ocean by the separation of Antarctica from southern Africa.
- Full Text:
- Date Issued: 1984
The mathematical experience : inaugural lecture delivered at Rhodes University
- Authors: Kotze, W.J.
- Date: 1984
- Language: English
- Type: Text
- Identifier: vital:644 , http://hdl.handle.net/10962/d1020713 , ISBN 0868101060
- Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1984
- Authors: Kotze, W.J.
- Date: 1984
- Language: English
- Type: Text
- Identifier: vital:644 , http://hdl.handle.net/10962/d1020713 , ISBN 0868101060
- Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1984
The petrology of the Merensky cyclic unit and associated rocks and their significance in the evolution of the Western Bushveld Complex
- Authors: Kruger, Floris Johan
- Date: 1984
- Subjects: Petrology -- Africa, Southern Petrofabric analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5006 , http://hdl.handle.net/10962/d1005636
- Description: A brief review of the various models proposed to account for the Bushveld Complex shows that there are two main hypotheses. These are the Multiple Intrusion hypothesis and the In Situ Crystallization hypothesis. The latter also allows for multiple additions to the crystallizing magma, and several variants involving the number of these inputs , their composition, volume and timing have been proposed. To facilitate description and investigation of the study section, the stratigraphic nomenclature of this part of the Rustenberg Layered Suite is revised and clarified. It is proposed that the boundary between the Critical Zone and Main Zone be placed at the base of the Merensky cyclic unit, and thus the whole of the Merensky and Bastard cyclic units are included in the Main Zone. Furthermore, the extremely confused terminology for smaller units within the Merensky and Bastard cyclic units is resolved by discarding the term Reef as a formal term and substituting lithological terms such as Merensky pegmatoid, Merensky pyroxenite, Bastard pyroxenite and Merensky mottled anorthosite etc. It is recommended that the term Reef be retained as an informal term to designate the mineralized horizon which may be mined, regardless of lithology. The term "pegmatoid" is restricted to stratiform or lensoid masses of coarse grained feldspathic pyroxenite or harzburgite which are part of the layered sequence. The transgressive vertical pipe-like, coarse-grained ultramafic "iron-rich bodies are termed "ultramafic pegmatites ". The main features of the Merensky and Bastard cyclic units are the regular chemical and mineralogical changes that occur with respect to stratigraphic height in these units. In the Merensky cyclic unit there is a smooth iron enrichment in the orthopyroxenes upward in the succession and a transition from pyroxenite at the base to mottled anorthosite at the top of the unit. The Bastard cyclic unit is broadly similar to the Merensky cyclic unit. A variety of textures and chemical features are in disequilibrium in some samples but not in others, and great complexity is evident wh en individual samples are studied in detail. The initial ⁸⁷Sr/⁸⁶Sr ratios of plagioclase separates and whole rocks from the study section show a distinct step-like increase in the Merensky cyclic unit to .70806 at the base of the, Merensky cyclic unit to .70806 at the base of the Bastard cyclic unit. In contrast , samples from below the Merensky cyclic unit have a constant initial Sr-isotopic ratio, as do the samples from the Bastard cyclic unit. These isotopic and chemical data, and available published geologic relationships suggest that a major new influx of basic magma occurred after the Footwall unit was deposited and that this mixed with the residual magma in the chamber and then precipitated the Merensky and Bastard cyclic units. The crystal settling theory as outlined by Wager and Brown (1968) fails to account for the chemical and stratigraphic variations observed in the study section. The theory of bottom crystallization, initially proposed by Jackson (1961), more adequately explains the features observed. Applying a model outlined by Irvine (1980a & b), it has been established from chemical data, that the Merensky cyclic unit crystallized from a magma layer with a thickness roughly equivalent to the average thickness of the cyclic unit itself (±10m). A similar exercise on the Bastard unit was not possible. The formation of the Footwall unit is still enigmatic. Infiltration metasomatism and sintering can modify the petrographic and chemical characteristics of rocks and minerals after deposition at the liquidus stage. During the solidification of the crystal mush a separate vapour phase may form in the crystal mush, which could move up through the crystal pile. This process may ultimately be responsible for the generation of potholes and pegmatoidal horizons, such as the Merensky pegmatoid. The upward increase in the initial ⁸⁷Sr/⁸⁶Sr ratio within the Merensky cyclic unit is strong evidence that infiltration metasomatism has played an important part in the generation of the Merensky cyclic unit. This process, coupled with fluid enrichment, may also result in the formation of pegmatoid layers. Sintering appears to have been a common process in the mottled anorthosites of the study section and may have severely reduced the amount of trapped interstitial liquid in these rocks.
- Full Text:
- Date Issued: 1984
- Authors: Kruger, Floris Johan
- Date: 1984
- Subjects: Petrology -- Africa, Southern Petrofabric analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5006 , http://hdl.handle.net/10962/d1005636
- Description: A brief review of the various models proposed to account for the Bushveld Complex shows that there are two main hypotheses. These are the Multiple Intrusion hypothesis and the In Situ Crystallization hypothesis. The latter also allows for multiple additions to the crystallizing magma, and several variants involving the number of these inputs , their composition, volume and timing have been proposed. To facilitate description and investigation of the study section, the stratigraphic nomenclature of this part of the Rustenberg Layered Suite is revised and clarified. It is proposed that the boundary between the Critical Zone and Main Zone be placed at the base of the Merensky cyclic unit, and thus the whole of the Merensky and Bastard cyclic units are included in the Main Zone. Furthermore, the extremely confused terminology for smaller units within the Merensky and Bastard cyclic units is resolved by discarding the term Reef as a formal term and substituting lithological terms such as Merensky pegmatoid, Merensky pyroxenite, Bastard pyroxenite and Merensky mottled anorthosite etc. It is recommended that the term Reef be retained as an informal term to designate the mineralized horizon which may be mined, regardless of lithology. The term "pegmatoid" is restricted to stratiform or lensoid masses of coarse grained feldspathic pyroxenite or harzburgite which are part of the layered sequence. The transgressive vertical pipe-like, coarse-grained ultramafic "iron-rich bodies are termed "ultramafic pegmatites ". The main features of the Merensky and Bastard cyclic units are the regular chemical and mineralogical changes that occur with respect to stratigraphic height in these units. In the Merensky cyclic unit there is a smooth iron enrichment in the orthopyroxenes upward in the succession and a transition from pyroxenite at the base to mottled anorthosite at the top of the unit. The Bastard cyclic unit is broadly similar to the Merensky cyclic unit. A variety of textures and chemical features are in disequilibrium in some samples but not in others, and great complexity is evident wh en individual samples are studied in detail. The initial ⁸⁷Sr/⁸⁶Sr ratios of plagioclase separates and whole rocks from the study section show a distinct step-like increase in the Merensky cyclic unit to .70806 at the base of the, Merensky cyclic unit to .70806 at the base of the Bastard cyclic unit. In contrast , samples from below the Merensky cyclic unit have a constant initial Sr-isotopic ratio, as do the samples from the Bastard cyclic unit. These isotopic and chemical data, and available published geologic relationships suggest that a major new influx of basic magma occurred after the Footwall unit was deposited and that this mixed with the residual magma in the chamber and then precipitated the Merensky and Bastard cyclic units. The crystal settling theory as outlined by Wager and Brown (1968) fails to account for the chemical and stratigraphic variations observed in the study section. The theory of bottom crystallization, initially proposed by Jackson (1961), more adequately explains the features observed. Applying a model outlined by Irvine (1980a & b), it has been established from chemical data, that the Merensky cyclic unit crystallized from a magma layer with a thickness roughly equivalent to the average thickness of the cyclic unit itself (±10m). A similar exercise on the Bastard unit was not possible. The formation of the Footwall unit is still enigmatic. Infiltration metasomatism and sintering can modify the petrographic and chemical characteristics of rocks and minerals after deposition at the liquidus stage. During the solidification of the crystal mush a separate vapour phase may form in the crystal mush, which could move up through the crystal pile. This process may ultimately be responsible for the generation of potholes and pegmatoidal horizons, such as the Merensky pegmatoid. The upward increase in the initial ⁸⁷Sr/⁸⁶Sr ratio within the Merensky cyclic unit is strong evidence that infiltration metasomatism has played an important part in the generation of the Merensky cyclic unit. This process, coupled with fluid enrichment, may also result in the formation of pegmatoid layers. Sintering appears to have been a common process in the mottled anorthosites of the study section and may have severely reduced the amount of trapped interstitial liquid in these rocks.
- Full Text:
- Date Issued: 1984
The population dynamics of the rock hyrax procavia capensis (Pallas, 1766) in the Mountain Zebra National Park
- Authors: Fourie, Leon Johan
- Date: 1984
- Subjects: Rock hyrax Mountain Zebra National Park (South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5743 , http://hdl.handle.net/10962/d1005429
- Description: The chief objective of the study was to investigate the population dynamics of the hyrax in the Mountain Zebra National Park (MZNP). To realise this objective information on growth, age determination, reproduction, habitat utilization, behaviour, parasites and mortality had to be gathered. The growth of hyrax in relation to age is described by means of Stevens asymptotic regression equations. Near asymptotic measurements are attained first in hind foot length (at 30-33 months of age), head/body length (at 37-39 months of age), girth (at 41-48 months of age) and body mass (at 68-70 months of age). Allometric growth of the various body measurements was investigated and useful predictive relationships for mass are presented. Age determination of hyrax was studied in detail. Cementum annuli counts provided reliable estimates of age. One primary cementum line is formed annually. The dried eye lens mass was an accurate means of age determination up to c. 72 months of age. A summary of findings which will facilitate age determination of dead animals or skulls, and live animals, is provided. Reproduction in the hyrax was studied with emphasis on breeding season, age-specific litter sizes, prenatal mortality and lactation. Male hyrax attained puberty at 15-17 months of age or one year later. Females generally attained puberty at 15-17 months of age. One female (1,4% of total shot sample for the specific age group) attained puberty at 4-5 months of age. Middle-aged hyrax had significantly larger litter sizes than younger animals. Hyrax in the MZNP feed on at least 80 different plant species belonging to 33 plant families. Crude protein of stomach contents and faecal samples showed little seasonal fluctuation implying that hyrax in the MZNP were on a stable quality diet. Female hyrax enjoyed a significantly better quality diet than males for the four month period prior to parturition and during the first two months of lactation. The crude protein values of faecal and stomach samples had a significant correlation. Body fat of male and female hyrax showed seasonal variation related to physiologically stressful periods. Seasonal differences in activity patterns were demonstrated. The basic structure of hyrax social organization is the multi-female kinship group that is matrilocal. Territorial dominant males maintain harems and exclude all other adult males. Peripheral males occupy areas on the periphery of the activity areas of other members of the hyrax colony. Peripheral males do not form bachelor groups and are normally younger than territorial males. It is suggested that territorial males are able to monopolize between 3-17 females in a successful and energetic manner. Both natal and breeding dispersal occurred, the former being considerably more extensive than the latter. The ecto- and endoparasites of hyrax were identified and their burdens quantified over a 13 month period. Juveniles had significantly larger burdens of ectoparasites than did adults. Information on age-specific mortality was obtained from skulls collected in the field and at black eagles' nests. Losses that occurred in the study population due to caracal and black eagle predation were quantified. Evidence is supplied which indicates that juvenile mortality may fluctuate markedly. The population dynamics of the hyrax population in the MZNP was studied by the use of time specific life-tables, models on population growth rates, population simulation models and sensitivity analysis. Sensitivity coefficients were used as a predictor of population regulation. Female juvenile mortality was considered to be the main regulating factor. Changes in fecundity schedule are important compensatory mechanisms and also play an important role in the regulation of a hyrax population. Predation, particularly by caracal, is thought to dampen population fluctuations.
- Full Text:
- Date Issued: 1984
- Authors: Fourie, Leon Johan
- Date: 1984
- Subjects: Rock hyrax Mountain Zebra National Park (South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5743 , http://hdl.handle.net/10962/d1005429
- Description: The chief objective of the study was to investigate the population dynamics of the hyrax in the Mountain Zebra National Park (MZNP). To realise this objective information on growth, age determination, reproduction, habitat utilization, behaviour, parasites and mortality had to be gathered. The growth of hyrax in relation to age is described by means of Stevens asymptotic regression equations. Near asymptotic measurements are attained first in hind foot length (at 30-33 months of age), head/body length (at 37-39 months of age), girth (at 41-48 months of age) and body mass (at 68-70 months of age). Allometric growth of the various body measurements was investigated and useful predictive relationships for mass are presented. Age determination of hyrax was studied in detail. Cementum annuli counts provided reliable estimates of age. One primary cementum line is formed annually. The dried eye lens mass was an accurate means of age determination up to c. 72 months of age. A summary of findings which will facilitate age determination of dead animals or skulls, and live animals, is provided. Reproduction in the hyrax was studied with emphasis on breeding season, age-specific litter sizes, prenatal mortality and lactation. Male hyrax attained puberty at 15-17 months of age or one year later. Females generally attained puberty at 15-17 months of age. One female (1,4% of total shot sample for the specific age group) attained puberty at 4-5 months of age. Middle-aged hyrax had significantly larger litter sizes than younger animals. Hyrax in the MZNP feed on at least 80 different plant species belonging to 33 plant families. Crude protein of stomach contents and faecal samples showed little seasonal fluctuation implying that hyrax in the MZNP were on a stable quality diet. Female hyrax enjoyed a significantly better quality diet than males for the four month period prior to parturition and during the first two months of lactation. The crude protein values of faecal and stomach samples had a significant correlation. Body fat of male and female hyrax showed seasonal variation related to physiologically stressful periods. Seasonal differences in activity patterns were demonstrated. The basic structure of hyrax social organization is the multi-female kinship group that is matrilocal. Territorial dominant males maintain harems and exclude all other adult males. Peripheral males occupy areas on the periphery of the activity areas of other members of the hyrax colony. Peripheral males do not form bachelor groups and are normally younger than territorial males. It is suggested that territorial males are able to monopolize between 3-17 females in a successful and energetic manner. Both natal and breeding dispersal occurred, the former being considerably more extensive than the latter. The ecto- and endoparasites of hyrax were identified and their burdens quantified over a 13 month period. Juveniles had significantly larger burdens of ectoparasites than did adults. Information on age-specific mortality was obtained from skulls collected in the field and at black eagles' nests. Losses that occurred in the study population due to caracal and black eagle predation were quantified. Evidence is supplied which indicates that juvenile mortality may fluctuate markedly. The population dynamics of the hyrax population in the MZNP was studied by the use of time specific life-tables, models on population growth rates, population simulation models and sensitivity analysis. Sensitivity coefficients were used as a predictor of population regulation. Female juvenile mortality was considered to be the main regulating factor. Changes in fecundity schedule are important compensatory mechanisms and also play an important role in the regulation of a hyrax population. Predation, particularly by caracal, is thought to dampen population fluctuations.
- Full Text:
- Date Issued: 1984
The practical and theoretical implications of pretreatment and posttreatment anxiety levels in alcoholic in-patients
- Authors: Thomson, Peter R S
- Date: 1984
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:21129 , http://hdl.handle.net/10962/6494
- Description: Pretreatment and posttreatment anxiety scores on the IPAT Anxiety Inventory and the Taylor Manifest Anxiety Scale were obtained from 27 alcoholic in-patients who participated in an alcoholic treatment programme. The treatment programme focused on abstinence and not on anxiety reduction. The results showed that there was a significant decrease between the pre- and the posttreatment anxiety scores on both measures . The duration of hospitalization or the attendance of group psychotherapy did not affect the decrease in anxiety scores. The implications of these results for Pattison's (1979) Multivariate Multimodal model of alcoholism are discussed.
- Full Text:
- Date Issued: 1984
- Authors: Thomson, Peter R S
- Date: 1984
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:21129 , http://hdl.handle.net/10962/6494
- Description: Pretreatment and posttreatment anxiety scores on the IPAT Anxiety Inventory and the Taylor Manifest Anxiety Scale were obtained from 27 alcoholic in-patients who participated in an alcoholic treatment programme. The treatment programme focused on abstinence and not on anxiety reduction. The results showed that there was a significant decrease between the pre- and the posttreatment anxiety scores on both measures . The duration of hospitalization or the attendance of group psychotherapy did not affect the decrease in anxiety scores. The implications of these results for Pattison's (1979) Multivariate Multimodal model of alcoholism are discussed.
- Full Text:
- Date Issued: 1984
The role of continental lithosphere in the generation of the Karoo volcanic rocks: evidence from combined Nd-and Sr-isotope studies
- Hawkesworth, C J, Marsh, Julian S, Duncan, Andrew R, Erlank, Anthony J, Norry, M J
- Authors: Hawkesworth, C J , Marsh, Julian S , Duncan, Andrew R , Erlank, Anthony J , Norry, M J
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/134165 , vital:37080 , https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6453596
- Description: 143Nd/144Nd, 87Sr/86Sr, Sm and Nd analyses are reported on suites of Karoo volcanic rocks from the four sub-areas of Nuanetsi-north Lebombo, south Lebombo, the Central area, and north-west SWA/Namibia. Only seven (12%) of the samples analysed have positive ENd values similar to those found in the majority of recent mantle-derived rocks. Most of the rest have negative ENd (-1.0 to -17.1) and positive ESr, (+3.0 to +240) and thus must contain at least a contribution from source areas which were both old, and had lower Sm/Nd and higher Rh/Sr ratios than the bulk earth.
- Full Text:
- Date Issued: 1984
- Authors: Hawkesworth, C J , Marsh, Julian S , Duncan, Andrew R , Erlank, Anthony J , Norry, M J
- Date: 1984
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/134165 , vital:37080 , https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetailamp;idt=6453596
- Description: 143Nd/144Nd, 87Sr/86Sr, Sm and Nd analyses are reported on suites of Karoo volcanic rocks from the four sub-areas of Nuanetsi-north Lebombo, south Lebombo, the Central area, and north-west SWA/Namibia. Only seven (12%) of the samples analysed have positive ENd values similar to those found in the majority of recent mantle-derived rocks. Most of the rest have negative ENd (-1.0 to -17.1) and positive ESr, (+3.0 to +240) and thus must contain at least a contribution from source areas which were both old, and had lower Sm/Nd and higher Rh/Sr ratios than the bulk earth.
- Full Text:
- Date Issued: 1984
The search for power and legitimacy in Black urban areas: the role of the Urban Councils Association of South Africa
- Authors: Atkinson, Doreen
- Date: 1984
- Subjects: Urban Councils Association of South Africa Neighborhood government -- South Africa Black people -- South Africa -- Politics and government
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/1864 , vital:20234 , ISBN 0868101141
- Description: Since their establishment in 1977, Community Councils, like their predecessors, have been severely criticised by urban blacks for their powerlessness. Councillors themselves are disappointed with their inability to improve the living and working conditions of their constituents, and are aware of the rejection of councils as a meaningful political forum by many sectors of black society. In 1978 the Urban Councils Association of South Africa (UCASA) was formed to tie together the ineffective Councils into a more forceful power bloc, which would provide Councils with greater legitimacy and political credibility in the community. By doing so, UCASA acts as a counter to the Administration Boards manned predominantly by whites; UCASA is therefore in the difficult position of operating within government- created structures, while challenging the very structure on which itself is based. This report will outline UCASA's structure and activities within the context of the controversial position of local black urban authorities. It will also be necessary to describe UCASA's political standpoints, both on issues relating to Community Councils and broader South African problems. Three dominant themes constantly recur: structural deficiencies within UCASA itself; tension between UCASA and white officials within Administration Boards and the Department of Co-operation and Development; and UCASA's reaction to left-wing critics who adhere to the non-collaborationist approach with regard to government-created institutions. These divergent attitudes to UCASA will be discussed in more detail towards the end of the paper; finally, an evaluation of UCASA's success in establishing itself as a focal point of pressure for reform from within the ranks of Community Councils will be presented. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Date Issued: 1984
- Authors: Atkinson, Doreen
- Date: 1984
- Subjects: Urban Councils Association of South Africa Neighborhood government -- South Africa Black people -- South Africa -- Politics and government
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/1864 , vital:20234 , ISBN 0868101141
- Description: Since their establishment in 1977, Community Councils, like their predecessors, have been severely criticised by urban blacks for their powerlessness. Councillors themselves are disappointed with their inability to improve the living and working conditions of their constituents, and are aware of the rejection of councils as a meaningful political forum by many sectors of black society. In 1978 the Urban Councils Association of South Africa (UCASA) was formed to tie together the ineffective Councils into a more forceful power bloc, which would provide Councils with greater legitimacy and political credibility in the community. By doing so, UCASA acts as a counter to the Administration Boards manned predominantly by whites; UCASA is therefore in the difficult position of operating within government- created structures, while challenging the very structure on which itself is based. This report will outline UCASA's structure and activities within the context of the controversial position of local black urban authorities. It will also be necessary to describe UCASA's political standpoints, both on issues relating to Community Councils and broader South African problems. Three dominant themes constantly recur: structural deficiencies within UCASA itself; tension between UCASA and white officials within Administration Boards and the Department of Co-operation and Development; and UCASA's reaction to left-wing critics who adhere to the non-collaborationist approach with regard to government-created institutions. These divergent attitudes to UCASA will be discussed in more detail towards the end of the paper; finally, an evaluation of UCASA's success in establishing itself as a focal point of pressure for reform from within the ranks of Community Councils will be presented. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Date Issued: 1984
The synthesis and properties of some polymer hydrogels
- Authors: Hird, Bryn
- Date: 1984 , 2013-04-05
- Subjects: Colloids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4428 , http://hdl.handle.net/10962/d1006975 , Colloids
- Description: The interactions between water molecules and polyelectrolyte species in aqueous solutions are reviewed and are used to infer interactions occuring in swollen crosslinked polyelectrolyte hydrogels. Linear poly(acrylic acid ) and derivatives neutralised to varying degrees with alkali-metal hydroxides are prepared and characterised. Samples of these compounds are crosslinked by 'Y - irradiation to form hydrogels. Hydration studies on linear polymers, crosslinked material and a commercial polyacrylate hydrogel indicate a possible hydration structure and provide some insight into the nature of water-polymer interactions within a sHollen polyacrylate gel. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1984
- Authors: Hird, Bryn
- Date: 1984 , 2013-04-05
- Subjects: Colloids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4428 , http://hdl.handle.net/10962/d1006975 , Colloids
- Description: The interactions between water molecules and polyelectrolyte species in aqueous solutions are reviewed and are used to infer interactions occuring in swollen crosslinked polyelectrolyte hydrogels. Linear poly(acrylic acid ) and derivatives neutralised to varying degrees with alkali-metal hydroxides are prepared and characterised. Samples of these compounds are crosslinked by 'Y - irradiation to form hydrogels. Hydration studies on linear polymers, crosslinked material and a commercial polyacrylate hydrogel indicate a possible hydration structure and provide some insight into the nature of water-polymer interactions within a sHollen polyacrylate gel. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1984