Aspects of the geochemistry of the Karroo dolerites and basalts of the north-eastern Cape
- Authors: Robey, Julian van Aardt
- Date: 1976
- Subjects: Diabase -- South Africa -- Cape of Good Hope , Basalt -- South Africa -- Cape of Good Hope , Geochemistry -- South Africa -- Cape of Good Hope
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5060 , http://hdl.handle.net/10962/d1013070
- Description: The Birds River Gabbro Complex is intruded into sediments of the Karroo Stormberg Group in the area SW of Dordrecht in the northeastern Cape. A geochemical investigation, restricted to the igneous rock suite, gabbro-ferrogabbro-ferrotholeiite, presents new major-element data as well as data for twelve trace elements - Ba, Sr, Rb, Zr, Y, Nb , Zn, Cu, Ni, Co, V and Cr. The strong degree of differentiation of Kokstad-type tholeiitic magma in the Birds River intrusion, as noted by previous investigators, is revealed in variation diagrams in which data are plotted against a simple index of fractionation. Later differentiates are strongly enriched in Si, Ti, Fe, Na, K, P, Ba, Rb, Zr, Y, Nb, Zn and Cu but depleted in Mg, Ca, AI, Ni, Co and Cr. Extreme differentiation resulted in a strong depletion of Ti, Fe, P, Cu and V in the most highly evolved ferrotholeiites. Field evidence suggests the initial emplacement of strongly fractionated magmatic residua derived from fractional crystallization processes in a magma chamber at depth during cauldron subsidence of a mass of sediments within an annular fracture. These porphyritic, in part glassy, ferrotholeiites are enriched in Si, Na, K, Ba, Zr, Rb, Y, Nb and Zn and were engulfed by a later episode of renewed hypabyssal intrusive activity from the original source area. The younger gabbro was emplaced in a series of closely-spaced heaves or pulses of relatively undifferentiated Kokstad-type magma. The gabbro differentiated in place to form ferrogabbros which chemically closely approximate ferrotholeiite compositions. toidal facies. Residual liquids crystallized as a pegmatoidal facies. A simple fractional crystallization path, modelled on the assumption that the gabbro and ferrotholeiite form a continuous series, indicates that the least evolved ferrotholeiite can be derived from the initial gabbro composition by the fractionation of major amounts of plagioclase and pyroxene but lesser amounts of olivine. Crystallization and removal of magnetite and other Fe-oxides were relatively more important during the later stages of differentiation. The variation of major- and trace-elements in tholeiitic Karroo magma under conditions of strong differentiation at Birds River serves as a framework for the regional study of the geochemistry of other Karroo dolerites and volcanics of the north-eastern Cape. New geochemical data are presented for a sample of thirty chilled and coarse-grained Karroo dolerites collected throughout the north eastern Cape. For the most part, the chilled dolerites are relatively undifferentiated and the average composition differs only slightly from that determined by Walker and Poldervaart (1949). Variation diagrams reveal the steady increase in Si, Al, Ca, Na, K and P and the residual trace elements Ba, Zr, Rb, Y, Nb and Zn with increasing differentiation of the dolerites from more basic types. The concentrations of K, Ba and Rb are highly variable in some Karroo dolerites while new data suggest that Nb levels in the dolerites are low, being generally less than 10 ppm. The strong variation of the K-related elements (K, Ba and Rb) as well as the large ranges determined for certain inter-element ratios, such as K/Rb, Zr/Nb and K/Zr in the chilled Karroo dolerites, suggest that factors other than fractional crystallization processes need to be considered to account for individual variations. Little correlation exists between petrographic type as defined by Walker and Poldervaart (1949) and geochemical character. New geochemical data are also presented for ten Karroo basaltic lavas from the lowermost horizons of the lava sequence exposed in the Barkly East area. Major- and trace-element data indicate that these earliest Karroo extrusives are on average enriched in Si and Rb but depleted in Co and Ni when compared with the averaged chilled Karroo dolerite. Compared with basalts from Lesotho, the Barkly East basalts are enriched in Si but depleted in Ni and possibly Nb, Cu and V. The andesite is markedly enriched in Si, Na, K, Ba, Sr, Rb, Zr and Nb but depleted in Mg, Ca, V, Ni , Cu, Co and Cr. The subdued rate of Ni depletion and the absence of olivine as a major phenocryst phase in the series basalt to andesite, in the Barkly East area, suggests that differentiation trends may be controlled by the fractional crystallization of orthopyroxene and plagioclase, the two common phenocrysts present in these volcanics. The strong depletion of V and Cu in the andesite may indicate some magnetite removal during fractional crystallization.
- Full Text:
- Date Issued: 1976
- Authors: Robey, Julian van Aardt
- Date: 1976
- Subjects: Diabase -- South Africa -- Cape of Good Hope , Basalt -- South Africa -- Cape of Good Hope , Geochemistry -- South Africa -- Cape of Good Hope
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5060 , http://hdl.handle.net/10962/d1013070
- Description: The Birds River Gabbro Complex is intruded into sediments of the Karroo Stormberg Group in the area SW of Dordrecht in the northeastern Cape. A geochemical investigation, restricted to the igneous rock suite, gabbro-ferrogabbro-ferrotholeiite, presents new major-element data as well as data for twelve trace elements - Ba, Sr, Rb, Zr, Y, Nb , Zn, Cu, Ni, Co, V and Cr. The strong degree of differentiation of Kokstad-type tholeiitic magma in the Birds River intrusion, as noted by previous investigators, is revealed in variation diagrams in which data are plotted against a simple index of fractionation. Later differentiates are strongly enriched in Si, Ti, Fe, Na, K, P, Ba, Rb, Zr, Y, Nb, Zn and Cu but depleted in Mg, Ca, AI, Ni, Co and Cr. Extreme differentiation resulted in a strong depletion of Ti, Fe, P, Cu and V in the most highly evolved ferrotholeiites. Field evidence suggests the initial emplacement of strongly fractionated magmatic residua derived from fractional crystallization processes in a magma chamber at depth during cauldron subsidence of a mass of sediments within an annular fracture. These porphyritic, in part glassy, ferrotholeiites are enriched in Si, Na, K, Ba, Zr, Rb, Y, Nb and Zn and were engulfed by a later episode of renewed hypabyssal intrusive activity from the original source area. The younger gabbro was emplaced in a series of closely-spaced heaves or pulses of relatively undifferentiated Kokstad-type magma. The gabbro differentiated in place to form ferrogabbros which chemically closely approximate ferrotholeiite compositions. toidal facies. Residual liquids crystallized as a pegmatoidal facies. A simple fractional crystallization path, modelled on the assumption that the gabbro and ferrotholeiite form a continuous series, indicates that the least evolved ferrotholeiite can be derived from the initial gabbro composition by the fractionation of major amounts of plagioclase and pyroxene but lesser amounts of olivine. Crystallization and removal of magnetite and other Fe-oxides were relatively more important during the later stages of differentiation. The variation of major- and trace-elements in tholeiitic Karroo magma under conditions of strong differentiation at Birds River serves as a framework for the regional study of the geochemistry of other Karroo dolerites and volcanics of the north-eastern Cape. New geochemical data are presented for a sample of thirty chilled and coarse-grained Karroo dolerites collected throughout the north eastern Cape. For the most part, the chilled dolerites are relatively undifferentiated and the average composition differs only slightly from that determined by Walker and Poldervaart (1949). Variation diagrams reveal the steady increase in Si, Al, Ca, Na, K and P and the residual trace elements Ba, Zr, Rb, Y, Nb and Zn with increasing differentiation of the dolerites from more basic types. The concentrations of K, Ba and Rb are highly variable in some Karroo dolerites while new data suggest that Nb levels in the dolerites are low, being generally less than 10 ppm. The strong variation of the K-related elements (K, Ba and Rb) as well as the large ranges determined for certain inter-element ratios, such as K/Rb, Zr/Nb and K/Zr in the chilled Karroo dolerites, suggest that factors other than fractional crystallization processes need to be considered to account for individual variations. Little correlation exists between petrographic type as defined by Walker and Poldervaart (1949) and geochemical character. New geochemical data are also presented for ten Karroo basaltic lavas from the lowermost horizons of the lava sequence exposed in the Barkly East area. Major- and trace-element data indicate that these earliest Karroo extrusives are on average enriched in Si and Rb but depleted in Co and Ni when compared with the averaged chilled Karroo dolerite. Compared with basalts from Lesotho, the Barkly East basalts are enriched in Si but depleted in Ni and possibly Nb, Cu and V. The andesite is markedly enriched in Si, Na, K, Ba, Sr, Rb, Zr and Nb but depleted in Mg, Ca, V, Ni , Cu, Co and Cr. The subdued rate of Ni depletion and the absence of olivine as a major phenocryst phase in the series basalt to andesite, in the Barkly East area, suggests that differentiation trends may be controlled by the fractional crystallization of orthopyroxene and plagioclase, the two common phenocrysts present in these volcanics. The strong depletion of V and Cu in the andesite may indicate some magnetite removal during fractional crystallization.
- Full Text:
- Date Issued: 1976
Self-esteem of coloured and white scholars and students in South Africa
- Authors: Momberg, Allan
- Date: 1976
- Subjects: Self-esteem in children , Self-esteem -- Cross-cultural studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3217 , http://hdl.handle.net/10962/d1012876
- Description: A measure of the self-esteem of 426 subjects was obtained by means of the Coopersmith Self-Esteem Inventory. The sample comprised two Afrikaans, two Coloured and two English groups. Each of the above three groups was made up of pupils and students, (i. e. there were six separate sample groups). The major purpose of this study was to ascertain whether or not the Coloureds could be said to differ meaningfully from their White counterparts with regard to their general level of self-esteem. A secondary objective was to investigate the possibility of the Afrikaans and English groups differing in self-esteem. No significant differences were found to exist between any of the three student sample groups. The ranking of the mean self-esteem scores of these groups was: Afrikaans (highest), Coloured, English (lowest). The only groups that differed significantly from one another at the pupil level were the Afrikaans and the Coloureds. Their ranking was: Afrikaans (highest), English, Coloured (lowest). The prediction arising from the hypothesis of this study was that the Coloureds do not necessarily differ from Whites in their general level of self-esteem. This view is held because factors similar to those which are believed to have facilitated the rise in the self-esteem of the American Negroes are now operating in South Africa. It was concluded that this prediction was upheld.
- Full Text:
- Date Issued: 1976
- Authors: Momberg, Allan
- Date: 1976
- Subjects: Self-esteem in children , Self-esteem -- Cross-cultural studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3217 , http://hdl.handle.net/10962/d1012876
- Description: A measure of the self-esteem of 426 subjects was obtained by means of the Coopersmith Self-Esteem Inventory. The sample comprised two Afrikaans, two Coloured and two English groups. Each of the above three groups was made up of pupils and students, (i. e. there were six separate sample groups). The major purpose of this study was to ascertain whether or not the Coloureds could be said to differ meaningfully from their White counterparts with regard to their general level of self-esteem. A secondary objective was to investigate the possibility of the Afrikaans and English groups differing in self-esteem. No significant differences were found to exist between any of the three student sample groups. The ranking of the mean self-esteem scores of these groups was: Afrikaans (highest), Coloured, English (lowest). The only groups that differed significantly from one another at the pupil level were the Afrikaans and the Coloureds. Their ranking was: Afrikaans (highest), English, Coloured (lowest). The prediction arising from the hypothesis of this study was that the Coloureds do not necessarily differ from Whites in their general level of self-esteem. This view is held because factors similar to those which are believed to have facilitated the rise in the self-esteem of the American Negroes are now operating in South Africa. It was concluded that this prediction was upheld.
- Full Text:
- Date Issued: 1976
Some problems of dialect lexicography with particular reference to the preparation of a draft of an illustrative, experientially categorised Dictionary of South African English
- Authors: Branford, Jean
- Date: 1976
- Subjects: English language -- Provincialisms -- South Africa -- Dictionaries English language -- South Africa English language -- Lexicography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3626 , http://hdl.handle.net/10962/d1009689
- Description: This dissertation consists in essence of an experiment and a commentary upon it. The text which constitutes Part II is a lexicographical experiment incorporating some features and treatments not usual in lexicography, and Part I consists of a discussion of the problems encountered, principles applied and procedures followed. Neither the matter nor the manner of the experiment, however, lends itself in the present state of our knowledge to the fully impersonal objectivity that is often claimed for the experiments in the physical sciences. At the same time every effort has been made to establish an unbiased record of the data and to maintain a certain methodological consistency. The main experimental feature of Part II is that it is an attempt to combine an orthodox, alphabetical dictionary with an experiential categorisation of the vocabulary, without repeating the entire data for each type of treatment. This has been done by means of a series of numbered, classified word-lists with a limited subject index as a guide to their use. The entries themselves, instead of being repeated in the order of their classification, are numbered according to the category or categories to which the word defined belongs. It can then, by means of its number(s), be found in its own lexical or experiential set (or sets) in the categorised section. This part of the work might be better described as lexicology rather than lexicography but does, I think, prove itself to be a useful adjunct to the A - Z lexicon proper. Apart from the detailed categorisation system the text contains three features not normally included in dictionaries of small compass: illustrative quotations, etymologies and a number of tentative parallels between South African and other varieties of English by means of cross-references to items of similar or related meaning or form in the English of Australia, Canada, the U.S.A., Hong Kong, Anglo-India and other 'overseas' English speech communities. Introduction, p. 1.
- Full Text:
- Date Issued: 1976
- Authors: Branford, Jean
- Date: 1976
- Subjects: English language -- Provincialisms -- South Africa -- Dictionaries English language -- South Africa English language -- Lexicography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3626 , http://hdl.handle.net/10962/d1009689
- Description: This dissertation consists in essence of an experiment and a commentary upon it. The text which constitutes Part II is a lexicographical experiment incorporating some features and treatments not usual in lexicography, and Part I consists of a discussion of the problems encountered, principles applied and procedures followed. Neither the matter nor the manner of the experiment, however, lends itself in the present state of our knowledge to the fully impersonal objectivity that is often claimed for the experiments in the physical sciences. At the same time every effort has been made to establish an unbiased record of the data and to maintain a certain methodological consistency. The main experimental feature of Part II is that it is an attempt to combine an orthodox, alphabetical dictionary with an experiential categorisation of the vocabulary, without repeating the entire data for each type of treatment. This has been done by means of a series of numbered, classified word-lists with a limited subject index as a guide to their use. The entries themselves, instead of being repeated in the order of their classification, are numbered according to the category or categories to which the word defined belongs. It can then, by means of its number(s), be found in its own lexical or experiential set (or sets) in the categorised section. This part of the work might be better described as lexicology rather than lexicography but does, I think, prove itself to be a useful adjunct to the A - Z lexicon proper. Apart from the detailed categorisation system the text contains three features not normally included in dictionaries of small compass: illustrative quotations, etymologies and a number of tentative parallels between South African and other varieties of English by means of cross-references to items of similar or related meaning or form in the English of Australia, Canada, the U.S.A., Hong Kong, Anglo-India and other 'overseas' English speech communities. Introduction, p. 1.
- Full Text:
- Date Issued: 1976
Rhodeo, Vol. 30, No. 2
- Date: 1976
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14670 , http://hdl.handle.net/10962/d1019542
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1976
- Date: 1976
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14670 , http://hdl.handle.net/10962/d1019542
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1976
The multiple image in art : a personal response
- Authors: Swift, Anthony J M
- Date: 1976
- Subjects: Art, Modern -- 20th century , Art -- Themes, motives , Art appreciation , Art, Modern -- 20th century -- Philosophy
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2497 , http://hdl.handle.net/10962/d1013330
- Description: The development of this thesis is akin to that of a painting. It is subject to various influences that have evoked ideas and each idea has stimulated other ideas, thus the continuity could have gone beyond the bounds of this work. It is not so much an amalgamation of similar ideas but a development of diverse ideas which have, once composed, a common factor - the Multiple Image. Image refers to some paintings that have been made or part of them, a photograph, a film, a subject visualized in the mind or a complex reforms which is suggestive. Multiple refers to anything that relatively repeats itself, has facsimilies of itself, triptychs, polyptychs or is a conglomeration of ideas in a work of art. Intro., p. 1.
- Full Text:
- Date Issued: 1976
- Authors: Swift, Anthony J M
- Date: 1976
- Subjects: Art, Modern -- 20th century , Art -- Themes, motives , Art appreciation , Art, Modern -- 20th century -- Philosophy
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2497 , http://hdl.handle.net/10962/d1013330
- Description: The development of this thesis is akin to that of a painting. It is subject to various influences that have evoked ideas and each idea has stimulated other ideas, thus the continuity could have gone beyond the bounds of this work. It is not so much an amalgamation of similar ideas but a development of diverse ideas which have, once composed, a common factor - the Multiple Image. Image refers to some paintings that have been made or part of them, a photograph, a film, a subject visualized in the mind or a complex reforms which is suggestive. Multiple refers to anything that relatively repeats itself, has facsimilies of itself, triptychs, polyptychs or is a conglomeration of ideas in a work of art. Intro., p. 1.
- Full Text:
- Date Issued: 1976
Die administratiewe funksionering van bewindsinstellings in die Ciskei met besondere verwysing na plaaslike bestuur
- Authors: Groenewald, David Marais
- Date: 1976
- Subjects: Public institutions -- Administration -- South Africa -- Ciskei , Public institutions -- Management -- South Africa -- Ciskei , Public institutions -- Government -- South Africa -- Ciskei
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:2877 , http://hdl.handle.net/10962/d1012099 , Public institutions -- Administration -- South Africa -- Ciskei , Public institutions -- Management -- South Africa -- Ciskei , Public institutions -- Government -- South Africa -- Ciskei
- Description: As gevolg van die ongekonsolideerde aard van die Bantoegebiede in die Ciskei is dit onmoontlik om diè gebied te begrens binne bepaalde relief kenmerke, soos bv. berge en riviere; of selfs binne administratiewe grense soos bv. magistraatsdistrikte. Intro., p. 1
- Full Text:
- Date Issued: 1976
- Authors: Groenewald, David Marais
- Date: 1976
- Subjects: Public institutions -- Administration -- South Africa -- Ciskei , Public institutions -- Management -- South Africa -- Ciskei , Public institutions -- Government -- South Africa -- Ciskei
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:2877 , http://hdl.handle.net/10962/d1012099 , Public institutions -- Administration -- South Africa -- Ciskei , Public institutions -- Management -- South Africa -- Ciskei , Public institutions -- Government -- South Africa -- Ciskei
- Description: As gevolg van die ongekonsolideerde aard van die Bantoegebiede in die Ciskei is dit onmoontlik om diè gebied te begrens binne bepaalde relief kenmerke, soos bv. berge en riviere; of selfs binne administratiewe grense soos bv. magistraatsdistrikte. Intro., p. 1
- Full Text:
- Date Issued: 1976
The keyboard sonatas of Pietro Augusto : an investigation into their formal and stylistic apsects
- Radloff, Timothy Edward Kingswell
- Authors: Radloff, Timothy Edward Kingswell
- Date: 1976
- Subjects: Augusto, Pietro , Sonatas (Piano)
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2689 , http://hdl.handle.net/10962/d1013047
- Description: This thesis supplements "The Piano Sonata of the Eighteenth Century in Germany" (Vol. 2 in the publication series "Contributions to the development of the Piano Sonata"). It does not aim at a comparative study between Pieto Augusto and his contemporaries but intends to establish the composer's individual characteristics in the light of the general development of the piano sonata during the eighteenth century.
- Full Text:
- Date Issued: 1976
- Authors: Radloff, Timothy Edward Kingswell
- Date: 1976
- Subjects: Augusto, Pietro , Sonatas (Piano)
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2689 , http://hdl.handle.net/10962/d1013047
- Description: This thesis supplements "The Piano Sonata of the Eighteenth Century in Germany" (Vol. 2 in the publication series "Contributions to the development of the Piano Sonata"). It does not aim at a comparative study between Pieto Augusto and his contemporaries but intends to establish the composer's individual characteristics in the light of the general development of the piano sonata during the eighteenth century.
- Full Text:
- Date Issued: 1976
A 22 GHz radio telescope
- Authors: Mutch, Laurence Ian
- Date: 1976
- Subjects: Radio telescopes , Paraboloid , Radio astronomy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5532 , http://hdl.handle.net/10962/d1012919
- Description: This thesis reports on the design, construction, testing and operation of the spectral line and continuum receivers built for the 22 GHz Radio Telescope. First results from 'the telescope were obtained and have been analysed to give an estimate of system efficiency. Tests have been performed on the front end and in particular on the 22 GHz mixer in order to determine the minimum detectable temperature. The Sun, Moon and major planets are sources suitable for antenna alignment and consequently a literature survey of emission at 22 GHz from elements of the Solar system has been made.
- Full Text:
- Date Issued: 1976
- Authors: Mutch, Laurence Ian
- Date: 1976
- Subjects: Radio telescopes , Paraboloid , Radio astronomy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5532 , http://hdl.handle.net/10962/d1012919
- Description: This thesis reports on the design, construction, testing and operation of the spectral line and continuum receivers built for the 22 GHz Radio Telescope. First results from 'the telescope were obtained and have been analysed to give an estimate of system efficiency. Tests have been performed on the front end and in particular on the 22 GHz mixer in order to determine the minimum detectable temperature. The Sun, Moon and major planets are sources suitable for antenna alignment and consequently a literature survey of emission at 22 GHz from elements of the Solar system has been made.
- Full Text:
- Date Issued: 1976
Rodin and his contemporaries
- Authors: Henderson, Derek Scott
- Subjects: Rodin, Auguste, 1840-1917
- Language: English
- Type: Text
- Identifier: vital:7344 , http://hdl.handle.net/10962/d1017073
- Description: Opening address at the launch of the exhibition titled Rodin and his contemporaries, ath King George VI, Art Gallery, Port Elizabeth, 1976
- Full Text:
- Authors: Henderson, Derek Scott
- Subjects: Rodin, Auguste, 1840-1917
- Language: English
- Type: Text
- Identifier: vital:7344 , http://hdl.handle.net/10962/d1017073
- Description: Opening address at the launch of the exhibition titled Rodin and his contemporaries, ath King George VI, Art Gallery, Port Elizabeth, 1976
- Full Text:
Bacterial degradation of the acaricide amitraz
- Authors: Baker, Penelope Bridget
- Date: 1976
- Subjects: Acaricides , Biodegradation , Gas chromatography , Bacteriology -- Cultures and culture media
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4099 , http://hdl.handle.net/10962/d1009498
- Description: This thesis describes dip tank field trials and laboratory investigations on the acaricide Amitraz. Amitraz is a triazapenta- diene compound which is relatively unstable in fouled dip washes. The field trials were conducted on the farm Sea View according to the "Total Replacement Method" and on the farm Sea Ways according to the "Lime Stabilization Method" of dipping. The results of these trials showed that Amitraz was stable in clean dip washes, and under conditions of high pH resulting from the addition of slaked lime to the dip wash. Using mixed bacterial populations optimum conditions for degradation of Amitraz in the laboratory were determined. Bacterial cultures degraded Amitraz most efficiently in media supplemented with yeast extract or with a high content of sterile cattle faeces. Amitraz concentrations were determined by gas chromatography. A culture. efficient at degrading Amitraz was enriched from a dip tank sludge inoculum. From this culture ten bacterial isolates were identified; nine of these were of the genus Pseudomonas and one was an Achromobacter sp. Experiments with both mixed and pure cultures demonstrated that bacterial degradation of Amitraz was by the process of co-metabolism. The existence of four degradation products was shown using thin layer chromatography. Tentative identification of two of the products was made.
- Full Text:
- Date Issued: 1976
- Authors: Baker, Penelope Bridget
- Date: 1976
- Subjects: Acaricides , Biodegradation , Gas chromatography , Bacteriology -- Cultures and culture media
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4099 , http://hdl.handle.net/10962/d1009498
- Description: This thesis describes dip tank field trials and laboratory investigations on the acaricide Amitraz. Amitraz is a triazapenta- diene compound which is relatively unstable in fouled dip washes. The field trials were conducted on the farm Sea View according to the "Total Replacement Method" and on the farm Sea Ways according to the "Lime Stabilization Method" of dipping. The results of these trials showed that Amitraz was stable in clean dip washes, and under conditions of high pH resulting from the addition of slaked lime to the dip wash. Using mixed bacterial populations optimum conditions for degradation of Amitraz in the laboratory were determined. Bacterial cultures degraded Amitraz most efficiently in media supplemented with yeast extract or with a high content of sterile cattle faeces. Amitraz concentrations were determined by gas chromatography. A culture. efficient at degrading Amitraz was enriched from a dip tank sludge inoculum. From this culture ten bacterial isolates were identified; nine of these were of the genus Pseudomonas and one was an Achromobacter sp. Experiments with both mixed and pure cultures demonstrated that bacterial degradation of Amitraz was by the process of co-metabolism. The existence of four degradation products was shown using thin layer chromatography. Tentative identification of two of the products was made.
- Full Text:
- Date Issued: 1976
Aspects of the feeding ecology of three common Sparid fish in the littoral zone at Clayton's Rocks in the Eastern Cape, with notes on their biology
- Authors: Christensen, Mikkel S
- Date: 1976
- Subjects: Sparidae -- Physiology , Sparidae -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5356 , http://hdl.handle.net/10962/d1010476 , Sparidae -- Physiology , Sparidae -- Ecology
- Description: The feeding interrelationships of three sparid fish was studied in the littoral zone during low tide at Clayton's Rocks in the Eastern Cape. The three species appeared in the study area only when between 9 and 10 mm long (SL), and remained resident until a length of approximately 120 fmm was reached. No sexually mature specimens occurred in the study area as large adults only use the intertidal zone for feeding purposes at high tide. From first recruitment into the littoral zone at 9 mm SL until some 35 mm long, the diet of Diplodus sargus consists of harpacticoid copepods and amphipods. Ingestion of amphipods and green algae increases with increased size of fish. Chironomid larvae, cirripede nauplii and an unidentifiable planktonic larva are important food items of small juveniles ( 50 mm), while diatoms are significant in larger juveniles (25 to 80 mm) in the spring/early summer season. The gut is short and the teeth are incisiform, backed by several rows of molars which increase in size and number with age. D.cervinus was almost completely carnivorous in the size range studied. The juveniles found on harpacticoid copepods and chironomid larvae while between 10 and 20 mm long. The diet then consists mainly of the shrimp Palaemon pacificus until the fish are 50 mm long and then amphipods until 100 mm long. All fish larger than this feed prodominantly on polychaetes. The gut is short and the teeth are similar to those of Q. sargus although there are fewer molars. From its first appearance at 10 mm, Sarpa salpa feeds mainly on harpacticoid copepods until 25 mm long. Diatoms then predominate in the diet, red algae also being taken until 75 mm long. Larger size classes are herbivores, feeding almost equally on red and green algae. Corresponding changes in gut length and dentition are reported, juveniles having a short gut and conical teeth and adults a long intestine and cuspidate, incisiform teeth. Marked ecological separation was observed between the three species. Spatial, temporal , behavioural and dietary differences were found . Q. sargus has continuous recruitment of juveniles into the littoral zone, S..salpa appears between July and early September and Q.cervinus is recruited from late September to November. Competition between small juveniles is reduced by cyclic abundances of food items important to each species and the sub-adults feed on different foods. Some competition exists between large juveniles of Q. sargus and Q.cervinus, but separation is maintained as individuals of the two species feed at different levels of the water column and in different parts of the littoral zone.
- Full Text:
- Date Issued: 1976
- Authors: Christensen, Mikkel S
- Date: 1976
- Subjects: Sparidae -- Physiology , Sparidae -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5356 , http://hdl.handle.net/10962/d1010476 , Sparidae -- Physiology , Sparidae -- Ecology
- Description: The feeding interrelationships of three sparid fish was studied in the littoral zone during low tide at Clayton's Rocks in the Eastern Cape. The three species appeared in the study area only when between 9 and 10 mm long (SL), and remained resident until a length of approximately 120 fmm was reached. No sexually mature specimens occurred in the study area as large adults only use the intertidal zone for feeding purposes at high tide. From first recruitment into the littoral zone at 9 mm SL until some 35 mm long, the diet of Diplodus sargus consists of harpacticoid copepods and amphipods. Ingestion of amphipods and green algae increases with increased size of fish. Chironomid larvae, cirripede nauplii and an unidentifiable planktonic larva are important food items of small juveniles ( 50 mm), while diatoms are significant in larger juveniles (25 to 80 mm) in the spring/early summer season. The gut is short and the teeth are incisiform, backed by several rows of molars which increase in size and number with age. D.cervinus was almost completely carnivorous in the size range studied. The juveniles found on harpacticoid copepods and chironomid larvae while between 10 and 20 mm long. The diet then consists mainly of the shrimp Palaemon pacificus until the fish are 50 mm long and then amphipods until 100 mm long. All fish larger than this feed prodominantly on polychaetes. The gut is short and the teeth are similar to those of Q. sargus although there are fewer molars. From its first appearance at 10 mm, Sarpa salpa feeds mainly on harpacticoid copepods until 25 mm long. Diatoms then predominate in the diet, red algae also being taken until 75 mm long. Larger size classes are herbivores, feeding almost equally on red and green algae. Corresponding changes in gut length and dentition are reported, juveniles having a short gut and conical teeth and adults a long intestine and cuspidate, incisiform teeth. Marked ecological separation was observed between the three species. Spatial, temporal , behavioural and dietary differences were found . Q. sargus has continuous recruitment of juveniles into the littoral zone, S..salpa appears between July and early September and Q.cervinus is recruited from late September to November. Competition between small juveniles is reduced by cyclic abundances of food items important to each species and the sub-adults feed on different foods. Some competition exists between large juveniles of Q. sargus and Q.cervinus, but separation is maintained as individuals of the two species feed at different levels of the water column and in different parts of the littoral zone.
- Full Text:
- Date Issued: 1976
Feeding ecology of the cichlid fish Sarotherodon Mossambicus in Lake Sibaya, KwaZulu
- Authors: Bowen, Stephen H
- Date: 1977
- Subjects: Cichlids -- Ecology , Fishes -- Ecology -- South Africa -- KwaZulu-Natal -- Sibaya, Lake
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5837 , http://hdl.handle.net/10962/d1009688 , Cichlids -- Ecology , Fishes -- Ecology -- South Africa -- KwaZulu-Natal -- Sibaya, Lake
- Description: The feeding of the cichlid fish Sarotherodon mossambicus in Lake Sibaya, KwaZulu, was studied in relation to various biotic and abiotic features of the l ake environment from January, 1973 to July, 1975. The primary goal of the study was to determine the cause of stunting and poor condition of adults in this population. Juvenile and adult S. mossambicus feed on a mixture of detritus, bacteria and diatoms that occurs as a flocculent layer on sand substrates throughout the lake. Concentrated gastric acid, commonly at pH values of 1.5 and lower, lyses diatoms and bacteria which are subsequently digested in the intestine. This is the first report of digestion of bacteria by a fish, and the nutritional significance of the finding is discussed. Juveniles feed predominantly on shallow sand terraces found along the margin of much of the lake, while adults usually feed in offshore waters at depths of 3 m and greater. Benthic floc from feeding areas of juveniles and adults have similar concentrations of organic matter, total carbohydrate, soluble carbohydrate and calories, but differ markedly in respect to diatom and protein concentration. Diatom concentrations are generally high in terrace floc but are consistently low in floc from deep water. Protein concentration of benthic floc decreases with increasing depth from 0 - 5 m. Partial correlation analysis shows that protein and diatom concentrations have no correlation independent. of their common relationship to depth, and the evidence implicates detrital bacteria as the primary source of protein in benthic floc. Probable causes of the observed distributions of diatoms and protein are discussed. The protein content of benthic floc profoundly influences its nutritional value. A comparison with available data on animal nutrition shows that the ratio of digestible protein to digestible energy in floc in the shallows is high enough that this food resource would be expected to support good growth, but the ratio for deep water floc is so low that it would be expected to result in conspicuous malnutrition. Thus, inadequate dietary protein is identified as the principal cause of stunting and poor condition of adult S· mossambicus in Lake Sibaya; It is argued that the ratio of digestible protein to digestible calories can be expected to determine the food value of particulate organic matter that includes amorphous detritus in other ecosystems. Despite stunting and poor condition of adults, S. mossambicus are abundant in Lake Sibaya. The precocious breeding of this population is discussed as an adaptation that allows it to maximize reproductive output given the limited resources available to adults. Juvenile S. mossambicus perform daily movements from deep water onto the terraces where they feed and then back into deep water. During periods of relatively low lake level when terrace waters were usually less than 1.5 m deep (1-73 to 1-74), juveniles were present on the terrace throughout daylight hours. At relatively high lake levels (7-74 to 8-75), juveniles were present on the terraces for only about five hours following sunset. Periods of heavy wave action interrupt feeding activity and result in reduced numbers of fish in terrace waters. The possible roles of predator avoidance and temperature in determination of daily feeding behavior are discussed. Daily energy assimilation by juveniles, estimated by a field technique, is approximately 115 cal per g fish dry weight.
- Full Text:
- Date Issued: 1977
- Authors: Bowen, Stephen H
- Date: 1977
- Subjects: Cichlids -- Ecology , Fishes -- Ecology -- South Africa -- KwaZulu-Natal -- Sibaya, Lake
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5837 , http://hdl.handle.net/10962/d1009688 , Cichlids -- Ecology , Fishes -- Ecology -- South Africa -- KwaZulu-Natal -- Sibaya, Lake
- Description: The feeding of the cichlid fish Sarotherodon mossambicus in Lake Sibaya, KwaZulu, was studied in relation to various biotic and abiotic features of the l ake environment from January, 1973 to July, 1975. The primary goal of the study was to determine the cause of stunting and poor condition of adults in this population. Juvenile and adult S. mossambicus feed on a mixture of detritus, bacteria and diatoms that occurs as a flocculent layer on sand substrates throughout the lake. Concentrated gastric acid, commonly at pH values of 1.5 and lower, lyses diatoms and bacteria which are subsequently digested in the intestine. This is the first report of digestion of bacteria by a fish, and the nutritional significance of the finding is discussed. Juveniles feed predominantly on shallow sand terraces found along the margin of much of the lake, while adults usually feed in offshore waters at depths of 3 m and greater. Benthic floc from feeding areas of juveniles and adults have similar concentrations of organic matter, total carbohydrate, soluble carbohydrate and calories, but differ markedly in respect to diatom and protein concentration. Diatom concentrations are generally high in terrace floc but are consistently low in floc from deep water. Protein concentration of benthic floc decreases with increasing depth from 0 - 5 m. Partial correlation analysis shows that protein and diatom concentrations have no correlation independent. of their common relationship to depth, and the evidence implicates detrital bacteria as the primary source of protein in benthic floc. Probable causes of the observed distributions of diatoms and protein are discussed. The protein content of benthic floc profoundly influences its nutritional value. A comparison with available data on animal nutrition shows that the ratio of digestible protein to digestible energy in floc in the shallows is high enough that this food resource would be expected to support good growth, but the ratio for deep water floc is so low that it would be expected to result in conspicuous malnutrition. Thus, inadequate dietary protein is identified as the principal cause of stunting and poor condition of adult S· mossambicus in Lake Sibaya; It is argued that the ratio of digestible protein to digestible calories can be expected to determine the food value of particulate organic matter that includes amorphous detritus in other ecosystems. Despite stunting and poor condition of adults, S. mossambicus are abundant in Lake Sibaya. The precocious breeding of this population is discussed as an adaptation that allows it to maximize reproductive output given the limited resources available to adults. Juvenile S. mossambicus perform daily movements from deep water onto the terraces where they feed and then back into deep water. During periods of relatively low lake level when terrace waters were usually less than 1.5 m deep (1-73 to 1-74), juveniles were present on the terrace throughout daylight hours. At relatively high lake levels (7-74 to 8-75), juveniles were present on the terraces for only about five hours following sunset. Periods of heavy wave action interrupt feeding activity and result in reduced numbers of fish in terrace waters. The possible roles of predator avoidance and temperature in determination of daily feeding behavior are discussed. Daily energy assimilation by juveniles, estimated by a field technique, is approximately 115 cal per g fish dry weight.
- Full Text:
- Date Issued: 1977
The term structure of interest rates in South Africa
- Authors: Dollery, Brian
- Date: 1976
- Subjects: Interest rates -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1083 , http://hdl.handle.net/10962/d1011180 , Interest rates -- South Africa
- Description: Since the late ' fifties the term structure of interest rates has attracted considerable attention from both theoretical and empirical economists. While potentially a very fruitful area for the application of the traditional methods of economic enquiry, the term structure has proved itself to be a potent testing ground for these tools, and consequently a wide range of sophisticated analytic devices have been introduced, Despite this, no general agreement has yet been reached and a number of crucial questions remain unanswered. It is our task in this dissertation to extend the enquiry into the South African context in an attempt to shed some light on the determination of the term structure of interest rates. Intro., p. 1.
- Full Text:
- Date Issued: 1976
- Authors: Dollery, Brian
- Date: 1976
- Subjects: Interest rates -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1083 , http://hdl.handle.net/10962/d1011180 , Interest rates -- South Africa
- Description: Since the late ' fifties the term structure of interest rates has attracted considerable attention from both theoretical and empirical economists. While potentially a very fruitful area for the application of the traditional methods of economic enquiry, the term structure has proved itself to be a potent testing ground for these tools, and consequently a wide range of sophisticated analytic devices have been introduced, Despite this, no general agreement has yet been reached and a number of crucial questions remain unanswered. It is our task in this dissertation to extend the enquiry into the South African context in an attempt to shed some light on the determination of the term structure of interest rates. Intro., p. 1.
- Full Text:
- Date Issued: 1976
Pre-release studies on Zophodia Tapiacola (Dyar) (Pyralidae : Lepidoptera) : a biological control agent against jointed cactus, Optuntia Aurantiaca Lindley
- Authors: Hoffmann, John Hugh
- Date: 1976
- Subjects: Pyralidae , Lepidoptera , Cactus , Weeds -- Biological control , Opuntia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5857 , http://hdl.handle.net/10962/d1012320 , Pyralidae , Lepidoptera , Cactus , Weeds -- Biological control , Opuntia
- Description: Jointed Cactus, Opuntia aurantiaca Lindley (see frontispiece), is the most important weed plant in South Africa, infesting approximately, 1,2 X 10¹° M² and costing approximately R240 000 per annum. Tordon herbicide effectively kills jointed cactus bushes to which it is applied. However, apart from being expensive and damaging to beneficial vegetation, spray programmes have not successfully controlled the weed because most small O. aurantiaca plants are impossible to detect in the field. Biological control may provide a solution to the problem. Two insects, the cochineal bug, Dactylopius austrinus De Lotto and the pyralid moth, Cactoblastis cactorum Berg., already exercise a degree of control over the weed. The introduction into South Africa of other natural enemies such as Zophodia tapiacola (Dyar) from Argentina, South America, may reduce the density of jointed cactus to below an acceptable economic threshold. Any insect considered for release should not colonise and destroy beneficial plants of which the culivated spineless cacti are the most vulnerable. Pre-release studies on Z. tapiacola have shown that it can only colonise a few species of low growing cacti and that it will not damage the large spineless cacti or other desirable plants. Further, the moths are relatively fecund and each larva destroys significant amounts of O. aurantiaca during its development. Consequently, Z. tapiacola is not only considered safe for release but it has the potential to act as a successful biological control agent of O. aurantiaca in South Africa.
- Full Text:
- Date Issued: 1976
- Authors: Hoffmann, John Hugh
- Date: 1976
- Subjects: Pyralidae , Lepidoptera , Cactus , Weeds -- Biological control , Opuntia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5857 , http://hdl.handle.net/10962/d1012320 , Pyralidae , Lepidoptera , Cactus , Weeds -- Biological control , Opuntia
- Description: Jointed Cactus, Opuntia aurantiaca Lindley (see frontispiece), is the most important weed plant in South Africa, infesting approximately, 1,2 X 10¹° M² and costing approximately R240 000 per annum. Tordon herbicide effectively kills jointed cactus bushes to which it is applied. However, apart from being expensive and damaging to beneficial vegetation, spray programmes have not successfully controlled the weed because most small O. aurantiaca plants are impossible to detect in the field. Biological control may provide a solution to the problem. Two insects, the cochineal bug, Dactylopius austrinus De Lotto and the pyralid moth, Cactoblastis cactorum Berg., already exercise a degree of control over the weed. The introduction into South Africa of other natural enemies such as Zophodia tapiacola (Dyar) from Argentina, South America, may reduce the density of jointed cactus to below an acceptable economic threshold. Any insect considered for release should not colonise and destroy beneficial plants of which the culivated spineless cacti are the most vulnerable. Pre-release studies on Z. tapiacola have shown that it can only colonise a few species of low growing cacti and that it will not damage the large spineless cacti or other desirable plants. Further, the moths are relatively fecund and each larva destroys significant amounts of O. aurantiaca during its development. Consequently, Z. tapiacola is not only considered safe for release but it has the potential to act as a successful biological control agent of O. aurantiaca in South Africa.
- Full Text:
- Date Issued: 1976
The influence of abiotic factors on the distribution of Biomphalaria pfeifferi (Krauss, 1848) (Planorbidae: Mollusca) and its lifecycle in South-Eastern Africa
- Appleton, Christopher Charles
- Authors: Appleton, Christopher Charles
- Date: 1976
- Subjects: Schistosomiasis , Mollusks as carriers of disease
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5835 , http://hdl.handle.net/10962/d1009495 , Schistosomiasis , Mollusks as carriers of disease
- Description: Previous studies on the influence of abiotic factors on the distribution of bilharzia intermediate host snails of the family Planorbidae are reviewed. Much of this work is basically descriptive and relatively few attempts have been made to examine the effects of these factors on snails in their natural habitats - to identify the factors precisely and to measure their critical levels. An account is given of recent studies on Eiomphalaria pfeifferi (Krauss) in two climatically different regions of southeastern Africa, at 6S5m altitude on the eastern Transvaal escarpment and 19m on the coastal peneplain of northern Zululand. These have shown the species to undergo a similar annual life-cycle of three overlapping generations in both areas. Further, in these areas where the snail has a discontinuous distribution, two abiotic factors, stream geology and water temperature, were found to be important in limiting its distribution. The longitudinal distribution of B. pfeifferi and another host snail Bulinus (Physopsis) globosus (Morelat), extended upstream in a perennial watercourse, the Gladdespruit, on the escarpment only as far as permanently lentic habitats were available. These habitats, usually detached from the channel, characterized the stream's lowest physical zone with its substratum of exposed granite, as opposed to the sandy-bottomed lotic zones upstream. The limit of the snails' occurrence lay close to the junction of these two substratum types. Granite is resistant to erosion but contains soft inclusions which erode more quickly than the hard matrix causing uneven weathering. This results in the formation of depressions in the stream bed (i.e. pools, potholes and backwaters) which provide the permanently lentic conditions necessary for the snails' survival. Temperature recordings made on this plain, upstream of the snails' limit, suggest that the water temperature here exceeded the critical lower levels required for a positive intrinsic rate of natural increase sufficiently often to permit the species to survive here, though not optimally. Above this point however, current velocities are continually in excess of the maximum tolerated (0.3 m/sec.) so that in this situation at least, current velocity is a dominant factor. A contrasting situation exists on the coastal peneplain of northern Zululand where B. pfeifferi occurs in some lentic habitats and not in others. This discontinuous distribution is shown to be related to the prolonged duration of temperatures above the level for optimal increase. The apparently suitable habitats from which B. pfeifferi was absent were found to be both very shallow and to experience these prolonged high temperatures during spring and early summer. This corresponds to the maturation period of the B. pfeifferi 1st generation as defined by Appleton (1974) and causes reduced fecundity probably through impaired gonad development. The density of its filial (2nd) generation is correspondingly reduced. A statistically significant partial-correlation (at a 1% level) was found between the fecundity of the 1st generation and increasing periods of temperatures above the species' optimal limit in the habitats involved during its maturation period (spring). It is interesting to nate here that B. (Ph.) globosus, which is known to be better adapted to high temperatures than B. pfeifferi (Shiff & Husting, 1966) occurred in all the waterbodies concerned. Both these factors therefore play important roles in determining the country-wide distribution pattern of the host snails. This distribution is closely correlated with the availability of permanently lentic habitats. In river systems, which form the main environment for these snails, such stable habitats occur almost entirely in low-gradient reaches over hard bed-rock which is resistant to erosion. Current velocities above 0.3 m/sec. render steeper reaches and those over soft, non-resistant rock and sand (unstable substrata) unsuitable and therefore constitute a most important limiting factor. Temperature however becomes a dominant factor in permanently lentic waterbodies. Biomphalaria pfeifferi is adversely affected by high temperature regimes and where such regimes occur in waterbodies which are too shallow to permit temperature gradient to develop, the species cannot survive whereas B. (Ph.) globosus can do so. This intolerance of high temperature regimes on the part of B. pfeifferi accounts for the species' adoption of a discontinuous distribution over the coastal plain of south-eastern Africa. A comparable pattern has been reported for the species over this plain northwards to approximately 16°S latitude in Mozambique and is probably due to a similar high-temperature effect. Further northwards in equatorial latitudes B. pfeifferi is restricted to the more elevated and cooler areas above an altitude of 500 - 600 m, probably because the very high temperature regimes prevailing in the lowlands there exclude the species altogether.
- Full Text:
- Date Issued: 1976
- Authors: Appleton, Christopher Charles
- Date: 1976
- Subjects: Schistosomiasis , Mollusks as carriers of disease
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5835 , http://hdl.handle.net/10962/d1009495 , Schistosomiasis , Mollusks as carriers of disease
- Description: Previous studies on the influence of abiotic factors on the distribution of bilharzia intermediate host snails of the family Planorbidae are reviewed. Much of this work is basically descriptive and relatively few attempts have been made to examine the effects of these factors on snails in their natural habitats - to identify the factors precisely and to measure their critical levels. An account is given of recent studies on Eiomphalaria pfeifferi (Krauss) in two climatically different regions of southeastern Africa, at 6S5m altitude on the eastern Transvaal escarpment and 19m on the coastal peneplain of northern Zululand. These have shown the species to undergo a similar annual life-cycle of three overlapping generations in both areas. Further, in these areas where the snail has a discontinuous distribution, two abiotic factors, stream geology and water temperature, were found to be important in limiting its distribution. The longitudinal distribution of B. pfeifferi and another host snail Bulinus (Physopsis) globosus (Morelat), extended upstream in a perennial watercourse, the Gladdespruit, on the escarpment only as far as permanently lentic habitats were available. These habitats, usually detached from the channel, characterized the stream's lowest physical zone with its substratum of exposed granite, as opposed to the sandy-bottomed lotic zones upstream. The limit of the snails' occurrence lay close to the junction of these two substratum types. Granite is resistant to erosion but contains soft inclusions which erode more quickly than the hard matrix causing uneven weathering. This results in the formation of depressions in the stream bed (i.e. pools, potholes and backwaters) which provide the permanently lentic conditions necessary for the snails' survival. Temperature recordings made on this plain, upstream of the snails' limit, suggest that the water temperature here exceeded the critical lower levels required for a positive intrinsic rate of natural increase sufficiently often to permit the species to survive here, though not optimally. Above this point however, current velocities are continually in excess of the maximum tolerated (0.3 m/sec.) so that in this situation at least, current velocity is a dominant factor. A contrasting situation exists on the coastal peneplain of northern Zululand where B. pfeifferi occurs in some lentic habitats and not in others. This discontinuous distribution is shown to be related to the prolonged duration of temperatures above the level for optimal increase. The apparently suitable habitats from which B. pfeifferi was absent were found to be both very shallow and to experience these prolonged high temperatures during spring and early summer. This corresponds to the maturation period of the B. pfeifferi 1st generation as defined by Appleton (1974) and causes reduced fecundity probably through impaired gonad development. The density of its filial (2nd) generation is correspondingly reduced. A statistically significant partial-correlation (at a 1% level) was found between the fecundity of the 1st generation and increasing periods of temperatures above the species' optimal limit in the habitats involved during its maturation period (spring). It is interesting to nate here that B. (Ph.) globosus, which is known to be better adapted to high temperatures than B. pfeifferi (Shiff & Husting, 1966) occurred in all the waterbodies concerned. Both these factors therefore play important roles in determining the country-wide distribution pattern of the host snails. This distribution is closely correlated with the availability of permanently lentic habitats. In river systems, which form the main environment for these snails, such stable habitats occur almost entirely in low-gradient reaches over hard bed-rock which is resistant to erosion. Current velocities above 0.3 m/sec. render steeper reaches and those over soft, non-resistant rock and sand (unstable substrata) unsuitable and therefore constitute a most important limiting factor. Temperature however becomes a dominant factor in permanently lentic waterbodies. Biomphalaria pfeifferi is adversely affected by high temperature regimes and where such regimes occur in waterbodies which are too shallow to permit temperature gradient to develop, the species cannot survive whereas B. (Ph.) globosus can do so. This intolerance of high temperature regimes on the part of B. pfeifferi accounts for the species' adoption of a discontinuous distribution over the coastal plain of south-eastern Africa. A comparable pattern has been reported for the species over this plain northwards to approximately 16°S latitude in Mozambique and is probably due to a similar high-temperature effect. Further northwards in equatorial latitudes B. pfeifferi is restricted to the more elevated and cooler areas above an altitude of 500 - 600 m, probably because the very high temperature regimes prevailing in the lowlands there exclude the species altogether.
- Full Text:
- Date Issued: 1976
A comparative Rorschach study of some responses of Schizophrenic and non-Schizophrenic Nguni female subjects
- Authors: Melane, Nompumelelo Popana
- Date: 1976
- Subjects: Rorschach Test , Schizophrenia -- Social aspects , Schizophrenia -- Treatment , Psychoanalysis -- Social aspects , Nguni (African people) -- Psychology , Women -- Mental health
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3216 , http://hdl.handle.net/10962/d1012873
- Description: Observation of the frequency with which major decisions on issues affecting psychiatric patients were decided on material elicited from techniques like the Rorschach stimulated the investigation of the applicability of this technique to African patients. The nosological group chosen for this study was the schizophrenic group. Scrutiny into the literature revealed great diversity in conceptions of the etiology of the schizophrenic condition. To handle this material it was necessary to adopt a modification of the framework used in Friedman and Kaplan (1974). Having gone into the models on etiology it was evident that consistency was only possible in the realm of symptoms and diagnosis and the definition of schizophrenia as a group of psychotic disorders characterised by gross distortions of reality : the disorganisation and fragmentation of perception, thought and emotion and withdrawal from social interaction, was adopted. With this preconceived idea of schizophrenia three hypotheses were formulated to test the diagnostic utility of the Rorschach with Nguni schizophrenic female subjects. Summary, p. 104.
- Full Text:
- Date Issued: 1976
- Authors: Melane, Nompumelelo Popana
- Date: 1976
- Subjects: Rorschach Test , Schizophrenia -- Social aspects , Schizophrenia -- Treatment , Psychoanalysis -- Social aspects , Nguni (African people) -- Psychology , Women -- Mental health
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3216 , http://hdl.handle.net/10962/d1012873
- Description: Observation of the frequency with which major decisions on issues affecting psychiatric patients were decided on material elicited from techniques like the Rorschach stimulated the investigation of the applicability of this technique to African patients. The nosological group chosen for this study was the schizophrenic group. Scrutiny into the literature revealed great diversity in conceptions of the etiology of the schizophrenic condition. To handle this material it was necessary to adopt a modification of the framework used in Friedman and Kaplan (1974). Having gone into the models on etiology it was evident that consistency was only possible in the realm of symptoms and diagnosis and the definition of schizophrenia as a group of psychotic disorders characterised by gross distortions of reality : the disorganisation and fragmentation of perception, thought and emotion and withdrawal from social interaction, was adopted. With this preconceived idea of schizophrenia three hypotheses were formulated to test the diagnostic utility of the Rorschach with Nguni schizophrenic female subjects. Summary, p. 104.
- Full Text:
- Date Issued: 1976
Brian Bradshaw
- Authors: Hogge, Rosemary
- Date: 1976
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2506 , http://hdl.handle.net/10962/d1016168
- Description: One assumes that Brian Bradshaw's career in art had been decided upon at an early age, but in fact it was not so. After he had attended the Canon Slade Grammar School in Bolton, his father suggested various options, some of them interesting, like becoming a veterinary surgeon, but that was rejected because although the boy liked 'putting things right' he didn't savour 'cutting things up'. For the same reason he couldn't follow the family tradition on his mother's side and become a doctor. Nor was his wish to become a sea-captain treated with any seriousness, although he thinks with nostalgia of life at sea; and he is pleased he didn't take up forestry because, although he loves the land and admires the art of designing the great gardens and parks which surrounded the Georgian and Regency houses of the 18th Century, he is appalled by the artificial mess they're making of the land now. So in that interim period before being conscripted, they suggested at home that he spend a few months at the Bolton Municipal School of Art under the guidance of Mr. John R. Gauld, and so his course was set for the future. He studied there for three years and was successful in obtaining the "drawing" and "pictorial design" certificates of the Ministry of Education, before joining His Majesty's Forces in 1942.
- Full Text:
- Date Issued: 1976
- Authors: Hogge, Rosemary
- Date: 1976
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2506 , http://hdl.handle.net/10962/d1016168
- Description: One assumes that Brian Bradshaw's career in art had been decided upon at an early age, but in fact it was not so. After he had attended the Canon Slade Grammar School in Bolton, his father suggested various options, some of them interesting, like becoming a veterinary surgeon, but that was rejected because although the boy liked 'putting things right' he didn't savour 'cutting things up'. For the same reason he couldn't follow the family tradition on his mother's side and become a doctor. Nor was his wish to become a sea-captain treated with any seriousness, although he thinks with nostalgia of life at sea; and he is pleased he didn't take up forestry because, although he loves the land and admires the art of designing the great gardens and parks which surrounded the Georgian and Regency houses of the 18th Century, he is appalled by the artificial mess they're making of the land now. So in that interim period before being conscripted, they suggested at home that he spend a few months at the Bolton Municipal School of Art under the guidance of Mr. John R. Gauld, and so his course was set for the future. He studied there for three years and was successful in obtaining the "drawing" and "pictorial design" certificates of the Ministry of Education, before joining His Majesty's Forces in 1942.
- Full Text:
- Date Issued: 1976
The vocation of man and the Great Commission: a theological dissertation based on the doctrine of reconciliation in Karl Barth's Church Dogmatics
- Authors: Fourie, Ethne Maud
- Date: 1976
- Subjects: Barth, Karl., 1886-1968 Theology, Doctrinal Great Commission (Bible) Reconciliation -- Biblical teaching
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1252 , http://hdl.handle.net/10962/d1011870
- Description: The purpose of this thesis is to establish a theological basis for an ecclesiology which takes account of the claim which the Lordship of Jesus Christ asserts over his appointed servants and the appropriate response from the Christian community corporately and from the members of the community individually. The interpretation and application of Christian discipleship by liturgical acts of the community in which the individual members participate and are prepared, trained and nourished for the purpose of equipping them for their corporate and individual task of witness is based on the promise and command of Jesus Christ recorded in Acts 1:8. The theological interpretation of the key concepts of the promise of power in the Holy Spirit and the commission to witness in the world is based on the theology of Karl Barth. Chapter I outlines the immediate context of the doctrine of vocation and the sending of the Christian community and the wider context of the doctrine of reconciliation and its place in the whole of theology. Chapters II and III enlarge on the vocation of man and the sending of the Christian community in the power of the Holy Spirit as the two parts of the doctrine of reconciliation which have particular relevance for our interpretation of the great commission. Chapter IV is devoted to a hypothesis of a special ethic based on Barth's unfinished work and Appendix A to methodological outline. Appendix B considers the practicality of this hypothesis in the light of two contemporary ecumenical interpretations and applications of the great commission. A concluding critique recognises the problems of the hypothesis and the inevitable problems that arise from any attempt to formulate a system or to define in precise categories the unique event of God's free and gracious love poured out and given to us in his Son, Jesus Christ our Lord.
- Full Text:
- Date Issued: 1976
- Authors: Fourie, Ethne Maud
- Date: 1976
- Subjects: Barth, Karl., 1886-1968 Theology, Doctrinal Great Commission (Bible) Reconciliation -- Biblical teaching
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1252 , http://hdl.handle.net/10962/d1011870
- Description: The purpose of this thesis is to establish a theological basis for an ecclesiology which takes account of the claim which the Lordship of Jesus Christ asserts over his appointed servants and the appropriate response from the Christian community corporately and from the members of the community individually. The interpretation and application of Christian discipleship by liturgical acts of the community in which the individual members participate and are prepared, trained and nourished for the purpose of equipping them for their corporate and individual task of witness is based on the promise and command of Jesus Christ recorded in Acts 1:8. The theological interpretation of the key concepts of the promise of power in the Holy Spirit and the commission to witness in the world is based on the theology of Karl Barth. Chapter I outlines the immediate context of the doctrine of vocation and the sending of the Christian community and the wider context of the doctrine of reconciliation and its place in the whole of theology. Chapters II and III enlarge on the vocation of man and the sending of the Christian community in the power of the Holy Spirit as the two parts of the doctrine of reconciliation which have particular relevance for our interpretation of the great commission. Chapter IV is devoted to a hypothesis of a special ethic based on Barth's unfinished work and Appendix A to methodological outline. Appendix B considers the practicality of this hypothesis in the light of two contemporary ecumenical interpretations and applications of the great commission. A concluding critique recognises the problems of the hypothesis and the inevitable problems that arise from any attempt to formulate a system or to define in precise categories the unique event of God's free and gracious love poured out and given to us in his Son, Jesus Christ our Lord.
- Full Text:
- Date Issued: 1976
Rhodes University Graduation Ceremony 1976
- Authors: Rhodes University
- Date: 1976
- Language: English
- Type: text
- Identifier: vital:8110 , http://hdl.handle.net/10962/d1004565
- Description: Rhodes University Graduation Ceremonies on Friday 9th April 1976 at 8 p.m. [and] on Saturday 10th April 1976 at 10:30 a.m.in the University Great Hall.
- Full Text:
- Date Issued: 1976
- Authors: Rhodes University
- Date: 1976
- Language: English
- Type: text
- Identifier: vital:8110 , http://hdl.handle.net/10962/d1004565
- Description: Rhodes University Graduation Ceremonies on Friday 9th April 1976 at 8 p.m. [and] on Saturday 10th April 1976 at 10:30 a.m.in the University Great Hall.
- Full Text:
- Date Issued: 1976
Agnation, alternative structures, and the individual in Chopi society
- Authors: Webster, D J
- Date: 1976
- Subjects: Chopi (African people) , Ethnology -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2122 , http://hdl.handle.net/10962/d1013288
- Full Text:
- Date Issued: 1976
- Authors: Webster, D J
- Date: 1976
- Subjects: Chopi (African people) , Ethnology -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2122 , http://hdl.handle.net/10962/d1013288
- Full Text:
- Date Issued: 1976