Theories of exchange rates and the methodology of economics
- Authors: Hodge, Duncan
- Date: 1997
- Subjects: Foreign exchange rates Economics -- Methodology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1012 , http://hdl.handle.net/10962/d1002747
- Description: This thesis is an exercise in applied methodology. Ideas in the history and philosophy of science which have proved to be influential in the methodology of economics, and in shaping economists' self-image in this regard, are selected for closer analysis and criticism. The main ideas that are addressed are those of empiricism, with emphasis on the methodological falsificationism of Karl Popper and Imre Lakatos, and Laudan's problem solving model of scientific progress . The thesis examines the relationship between empirical evidence, in the form of both econometric test results and stylized facts, and the development of theories about exchange rates and the open economy. This analysis begins with Cassel's formulation of purchasing power parity theory in 1916, through the elasticities, absorption, and Mundell-Fleming models of exchange rates and the balance of payments, up to the present day monetary and asset market models. This is done with regard to the broad methodological issues examined earlier in the thesis. Some of the main empirical and methodological difficulties in testing such theories are addressed, with particular reference to the role played by the Duhem-Quine thesis and the ceteris paribus assumption. Although some of these difficulties may be regarded as a matter of degree compared to similar problems in the natural sciences, it is argued that this difference is significant for the workability of falsification in economics . Moreover, the presence of hypotheses about expectations in many economic theories appears to be a substantive difference such that the difficulties posed by the Duhem-Quine thesis apply with much greater force in a social science like economics. The main conclusions are that neither the Popperian nor Lakatosian versions of falsification are seriously practiced in the area of exchange rate economics and that, unlike the position taken by advocates of falsification such as Mark Blaug, it would be inappropriate and misguided to do so. A tentative case is made, with some reference to the theories surveyed in this thesis, for the possibly greater relevance of Laudan' s more pragmatic problem solving model for the methodology of economics, particularly as regards his analysis and emphasis on conceptual problem solving in the progress of knowledge.
- Full Text:
- Date Issued: 1997
- Authors: Hodge, Duncan
- Date: 1997
- Subjects: Foreign exchange rates Economics -- Methodology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1012 , http://hdl.handle.net/10962/d1002747
- Description: This thesis is an exercise in applied methodology. Ideas in the history and philosophy of science which have proved to be influential in the methodology of economics, and in shaping economists' self-image in this regard, are selected for closer analysis and criticism. The main ideas that are addressed are those of empiricism, with emphasis on the methodological falsificationism of Karl Popper and Imre Lakatos, and Laudan's problem solving model of scientific progress . The thesis examines the relationship between empirical evidence, in the form of both econometric test results and stylized facts, and the development of theories about exchange rates and the open economy. This analysis begins with Cassel's formulation of purchasing power parity theory in 1916, through the elasticities, absorption, and Mundell-Fleming models of exchange rates and the balance of payments, up to the present day monetary and asset market models. This is done with regard to the broad methodological issues examined earlier in the thesis. Some of the main empirical and methodological difficulties in testing such theories are addressed, with particular reference to the role played by the Duhem-Quine thesis and the ceteris paribus assumption. Although some of these difficulties may be regarded as a matter of degree compared to similar problems in the natural sciences, it is argued that this difference is significant for the workability of falsification in economics . Moreover, the presence of hypotheses about expectations in many economic theories appears to be a substantive difference such that the difficulties posed by the Duhem-Quine thesis apply with much greater force in a social science like economics. The main conclusions are that neither the Popperian nor Lakatosian versions of falsification are seriously practiced in the area of exchange rate economics and that, unlike the position taken by advocates of falsification such as Mark Blaug, it would be inappropriate and misguided to do so. A tentative case is made, with some reference to the theories surveyed in this thesis, for the possibly greater relevance of Laudan' s more pragmatic problem solving model for the methodology of economics, particularly as regards his analysis and emphasis on conceptual problem solving in the progress of knowledge.
- Full Text:
- Date Issued: 1997
Theories of economic underdevelopment: a general equilibrium analysis
- Authors: Black, Philip Andrew
- Date: 1982
- Subjects: Equilibrium (Economics) -- Mathematical models Economic development -- Mathematical models Developing countries -- Economic conditions -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1049 , http://hdl.handle.net/10962/d1006235
- Description: This thesis is mainly concerned with the question whether 'conventional' economic theory - especially the neoclassical theory of general equilibrium - is sufficiently flexible to accommodate the particular conditions prevailing in the developing countries. It is argued that most existing theories of economic underdevelopment adopt an interpretative approach which essentially amounts to relaxing some of the chief assumptions of the neoclassical theory. When applied to the two-sector model of general equilibrium, these theories generally yield predictions which are vastly different from those associated with the neoclassical assumptions of perfect competition, unlimited factor substitutability and unrestricted resource mobility. Several theories seek to explain the development problem in terms of the specific production processes used in poor countries. Myrdal's (1957) theory of cumulative causation, for example, effectively introduces increasing returns to scale in at least one sector or region of the economy; in contrast to the neoclassical theory, he thus nvisages a cumulative process of regional divergence in the output level per worker. Similarly, Richard Eckaus's (1955) explanation of the "factor-proportions problem" is based on the assumption of limited factor substitutability. This enables him to establish the existence of a so-called "unemployment equiIibrium", thus implying that developing countries may be faced with a conflict between the objective of maximizing social -welfare on the one hand, and that of full employment on the other. More recently, Leibenstein (1960) has shown that this trade-off may be complicated by the introduction of capital-biased technological inventions and innovations. The solution to the factor-proportions problem consists in the adoption of more appropriate, usually labour-biased technologies, increased capital formation and a reduction in the rate of population growth. Much of the postwar literature on economic development has focused on the imperfectly competitive structure of the product and the factor markets in developing countries. Myint (1954) has highlighted the role played by monopolies and ligopolies during the "opening-up" process of economic development. Likewise, both Lewis's (1954) dualist theory and Todaro's (1969; 1971) model of rural-urban migration attempt to explain the unemployment problem in terms of various factor price distortions. In an international context, Prebisch (1950; 1959) and Singer (1950) have again shown how prevailing differences in the structure of markets between developed and developing countries may turn the terms of trade against the latter; using a two-sector model, Bhagwati (1958) has demonstrated that such a deterioration in the terms of trade could bring about a net decrease in the welfare level of the countries concerned. Generally, the policy measures relevant to the "market imperfections" problem include the creation of job opportunities in the rural (rather than urban) sector, the encouragement of informal-sector enterprises,and the imposition of factor taxes and subsidies as a means of counteracting the adverse effect of factor price distortions on employment. A more recent approach to the unemployment problem is the plea by the International Labor Office (1970; 1972) for a redistribution of income within the developing countries. In terms of the two-sector model, such a policy may well succeed in eliminating labour unemployment caused by fixed factor proportions and/or factor price distortions. It should be realized, though, that a redistribution of income may lower the aggregate savings level, and hence also the growth rates of capital and labour employment in the economy. On the whole, it would seem that these theories do indeed adopt a modified version of the neoclassical theory in providing a fairly comprehensive explanation of the economic problems of labour unemployment, low incomes and inequality.
- Full Text:
- Date Issued: 1982
- Authors: Black, Philip Andrew
- Date: 1982
- Subjects: Equilibrium (Economics) -- Mathematical models Economic development -- Mathematical models Developing countries -- Economic conditions -- Mathematical models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1049 , http://hdl.handle.net/10962/d1006235
- Description: This thesis is mainly concerned with the question whether 'conventional' economic theory - especially the neoclassical theory of general equilibrium - is sufficiently flexible to accommodate the particular conditions prevailing in the developing countries. It is argued that most existing theories of economic underdevelopment adopt an interpretative approach which essentially amounts to relaxing some of the chief assumptions of the neoclassical theory. When applied to the two-sector model of general equilibrium, these theories generally yield predictions which are vastly different from those associated with the neoclassical assumptions of perfect competition, unlimited factor substitutability and unrestricted resource mobility. Several theories seek to explain the development problem in terms of the specific production processes used in poor countries. Myrdal's (1957) theory of cumulative causation, for example, effectively introduces increasing returns to scale in at least one sector or region of the economy; in contrast to the neoclassical theory, he thus nvisages a cumulative process of regional divergence in the output level per worker. Similarly, Richard Eckaus's (1955) explanation of the "factor-proportions problem" is based on the assumption of limited factor substitutability. This enables him to establish the existence of a so-called "unemployment equiIibrium", thus implying that developing countries may be faced with a conflict between the objective of maximizing social -welfare on the one hand, and that of full employment on the other. More recently, Leibenstein (1960) has shown that this trade-off may be complicated by the introduction of capital-biased technological inventions and innovations. The solution to the factor-proportions problem consists in the adoption of more appropriate, usually labour-biased technologies, increased capital formation and a reduction in the rate of population growth. Much of the postwar literature on economic development has focused on the imperfectly competitive structure of the product and the factor markets in developing countries. Myint (1954) has highlighted the role played by monopolies and ligopolies during the "opening-up" process of economic development. Likewise, both Lewis's (1954) dualist theory and Todaro's (1969; 1971) model of rural-urban migration attempt to explain the unemployment problem in terms of various factor price distortions. In an international context, Prebisch (1950; 1959) and Singer (1950) have again shown how prevailing differences in the structure of markets between developed and developing countries may turn the terms of trade against the latter; using a two-sector model, Bhagwati (1958) has demonstrated that such a deterioration in the terms of trade could bring about a net decrease in the welfare level of the countries concerned. Generally, the policy measures relevant to the "market imperfections" problem include the creation of job opportunities in the rural (rather than urban) sector, the encouragement of informal-sector enterprises,and the imposition of factor taxes and subsidies as a means of counteracting the adverse effect of factor price distortions on employment. A more recent approach to the unemployment problem is the plea by the International Labor Office (1970; 1972) for a redistribution of income within the developing countries. In terms of the two-sector model, such a policy may well succeed in eliminating labour unemployment caused by fixed factor proportions and/or factor price distortions. It should be realized, though, that a redistribution of income may lower the aggregate savings level, and hence also the growth rates of capital and labour employment in the economy. On the whole, it would seem that these theories do indeed adopt a modified version of the neoclassical theory in providing a fairly comprehensive explanation of the economic problems of labour unemployment, low incomes and inequality.
- Full Text:
- Date Issued: 1982
Theoretical aspects of the reaction of zirconium compunds and vegetable tannins with the chromium-collagen complex
- Williams-Wynn, David Ernest Arthur
- Authors: Williams-Wynn, David Ernest Arthur
- Date: 1969
- Subjects: Zirconium compounds , Collagen , Chromium compounds , Tannins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4512 , http://hdl.handle.net/10962/d1013455
- Description: Studies have been made of the reactions which take place when zirconium compounds and vegetable tannins react with chromium tanned leather, in order to elucidate the mechanisms of the reactions which occur on retannage. Statistical procedures have been used in all investigations because of the variable nature of the substrate, and computer techniques have been applied to the repetitive statistical computations. Although chromium and vegetable tannages are well understood, further information on the reaction of zirconium with collagen was necessary before attempting to interpret the results of the studies of combination tannages with chromium, and this has been obtained by a comparative study of the reactions of chromium and zirconium with modified collagen. It is concluded that the mechanism of the reaction of basic zirconium sulphate with collagen is multipoint attachment of the tanning material by residual valency forces, although charge effects with basic groups may be supplementary. Zirconyl chloride reacts with carboxyl groups but does not form satisfactory, stable cross-links with collagen. Further evidence for this theory was obtained from the investigation of the reaction of zirconium compounds with chromium tanned collagen. Zirconyl sulphate does not interfere with effective chromium tannage and therefore can have little affinity for the carboxyl groups on the protein, but it displaces chromium complexes loosely held by auxiliary valencies without reducing the shrinkage temperature of the chromium leather Zirconyl chloride, although only fixed to a limited extent, apparently forms co-ordination compounds with the carboxyl groups, disrupting the chromium tannage because there is an over-all loss of hydrothermal stability. There is no evidence that zirconium co-ordinates with, or releases acid from chromium-collagen complexes, since combination chromium/zirconium tanned leathers are stable on storage. Retannage of chromium tanned leather with vegetable tanning materials generally results in loss of strength and a product which tends to deteriorate on ageing. Lower initial strength is probably due to the increased avidity of chromium tanned pelt for vegetable tannins, resulting from the liberation of internally neutralised reactive sites which are not normally available in vegetable tannage, and from the co- ordination of vegetable tannins and non-tannins to the chromium complex with the displacement of sulphate radicals. From a study of the retannage of chromium tanned modified collagen, it appears that basic groups probably play an important part in the rapid absorption of vegetable tannin. These reactions result in overloading of the fibre and an increased number of cross-links, both of which tend to produce weak leather. Deterioration with age is primarily a hydrolytic degradation of the protein which is catalysed by acid liberated from the chromium complexes by the entry of vegetable tannins, those factors which favour the formation of acid causing greater and more rapid deterioration.
- Full Text:
- Date Issued: 1969
- Authors: Williams-Wynn, David Ernest Arthur
- Date: 1969
- Subjects: Zirconium compounds , Collagen , Chromium compounds , Tannins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4512 , http://hdl.handle.net/10962/d1013455
- Description: Studies have been made of the reactions which take place when zirconium compounds and vegetable tannins react with chromium tanned leather, in order to elucidate the mechanisms of the reactions which occur on retannage. Statistical procedures have been used in all investigations because of the variable nature of the substrate, and computer techniques have been applied to the repetitive statistical computations. Although chromium and vegetable tannages are well understood, further information on the reaction of zirconium with collagen was necessary before attempting to interpret the results of the studies of combination tannages with chromium, and this has been obtained by a comparative study of the reactions of chromium and zirconium with modified collagen. It is concluded that the mechanism of the reaction of basic zirconium sulphate with collagen is multipoint attachment of the tanning material by residual valency forces, although charge effects with basic groups may be supplementary. Zirconyl chloride reacts with carboxyl groups but does not form satisfactory, stable cross-links with collagen. Further evidence for this theory was obtained from the investigation of the reaction of zirconium compounds with chromium tanned collagen. Zirconyl sulphate does not interfere with effective chromium tannage and therefore can have little affinity for the carboxyl groups on the protein, but it displaces chromium complexes loosely held by auxiliary valencies without reducing the shrinkage temperature of the chromium leather Zirconyl chloride, although only fixed to a limited extent, apparently forms co-ordination compounds with the carboxyl groups, disrupting the chromium tannage because there is an over-all loss of hydrothermal stability. There is no evidence that zirconium co-ordinates with, or releases acid from chromium-collagen complexes, since combination chromium/zirconium tanned leathers are stable on storage. Retannage of chromium tanned leather with vegetable tanning materials generally results in loss of strength and a product which tends to deteriorate on ageing. Lower initial strength is probably due to the increased avidity of chromium tanned pelt for vegetable tannins, resulting from the liberation of internally neutralised reactive sites which are not normally available in vegetable tannage, and from the co- ordination of vegetable tannins and non-tannins to the chromium complex with the displacement of sulphate radicals. From a study of the retannage of chromium tanned modified collagen, it appears that basic groups probably play an important part in the rapid absorption of vegetable tannin. These reactions result in overloading of the fibre and an increased number of cross-links, both of which tend to produce weak leather. Deterioration with age is primarily a hydrolytic degradation of the protein which is catalysed by acid liberated from the chromium complexes by the entry of vegetable tannins, those factors which favour the formation of acid causing greater and more rapid deterioration.
- Full Text:
- Date Issued: 1969
The zonation of coastal dune plants in relation to sand burial, resource availability and physiological adaptation
- Authors: Gilbert, Matthew Edmund
- Date: 2008
- Subjects: Sand dune conservation -- South Africa -- Eastern Cape Coastal ecology -- South Africa -- Eastern Cape Botany -- South Africa -- Eastern Cape Coastal biology -- South Africa -- Eastern Cape Littoral plants -- South Africa -- Eastern Cape Littoral plants Sand dune plants -- Ecophysiology Sand dune plants -- Geographical distribution
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4195 , http://hdl.handle.net/10962/d1003764
- Description: When considering the large amount of work done on dune ecology, and that a number of the classical ecological theories originate from work on dunes, it is apparent that there remains a need for physiological and mechanistic explanations of dune plant phenomena. This thesis demonstrated that in the extreme coastal environment dune plants must survive both high rates of burial (disturbance), and low nutrient availability (stress). The ability of four species to respond to these two factors corresponded with their position in a vegetation gradient on the dunes. A low stem tissue density was shown to enhance the potential stem elongation rate of buried plants, but reduced the maximum height to which a plant could grow. Such a tradeoff implies that tall light-competitive plants are able to survive only in stable areas, while burial responsive mobile-dune plants are limited to areas of low vegetation height. This stem tissue density tradeoff was suggested as the mechanism determining the zonation that species show within the dune vegetation gradient present at various sites in South Africa. Finally, detailed investigations of dune plant ecophysiology found that: 1) The resources used in the response to burial derive from external sources of carbon and nitrogen, as well as simple physiological and physical mechanisms of resource allocation. 2) The leaves of dune plants were found to be operating at one extreme of the photosynthetic continuum; viz efficient use of leaf nitrogen at the expense of water loss. 3) Contrary to other ecosystems, the environmental characteristics of dunes may allow plants to occupy a high disturbance, high stress niche, through the maintenance of lowered competition. 4) At least two mobile-dune species form steep dunes, and are able to optimise growth, on steeper dunes, such that they have to grow less in response to burial than plants that form more shallow dunes. In this thesis, it was shown that the link between the carbon and nitrogen economies of dune plants was pivotal in determining species distributions and survival under extreme environmental conditions. As vast areas of the world’s surface are covered by sand dunes these observations are not just of passing interest.
- Full Text:
- Date Issued: 2008
- Authors: Gilbert, Matthew Edmund
- Date: 2008
- Subjects: Sand dune conservation -- South Africa -- Eastern Cape Coastal ecology -- South Africa -- Eastern Cape Botany -- South Africa -- Eastern Cape Coastal biology -- South Africa -- Eastern Cape Littoral plants -- South Africa -- Eastern Cape Littoral plants Sand dune plants -- Ecophysiology Sand dune plants -- Geographical distribution
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4195 , http://hdl.handle.net/10962/d1003764
- Description: When considering the large amount of work done on dune ecology, and that a number of the classical ecological theories originate from work on dunes, it is apparent that there remains a need for physiological and mechanistic explanations of dune plant phenomena. This thesis demonstrated that in the extreme coastal environment dune plants must survive both high rates of burial (disturbance), and low nutrient availability (stress). The ability of four species to respond to these two factors corresponded with their position in a vegetation gradient on the dunes. A low stem tissue density was shown to enhance the potential stem elongation rate of buried plants, but reduced the maximum height to which a plant could grow. Such a tradeoff implies that tall light-competitive plants are able to survive only in stable areas, while burial responsive mobile-dune plants are limited to areas of low vegetation height. This stem tissue density tradeoff was suggested as the mechanism determining the zonation that species show within the dune vegetation gradient present at various sites in South Africa. Finally, detailed investigations of dune plant ecophysiology found that: 1) The resources used in the response to burial derive from external sources of carbon and nitrogen, as well as simple physiological and physical mechanisms of resource allocation. 2) The leaves of dune plants were found to be operating at one extreme of the photosynthetic continuum; viz efficient use of leaf nitrogen at the expense of water loss. 3) Contrary to other ecosystems, the environmental characteristics of dunes may allow plants to occupy a high disturbance, high stress niche, through the maintenance of lowered competition. 4) At least two mobile-dune species form steep dunes, and are able to optimise growth, on steeper dunes, such that they have to grow less in response to burial than plants that form more shallow dunes. In this thesis, it was shown that the link between the carbon and nitrogen economies of dune plants was pivotal in determining species distributions and survival under extreme environmental conditions. As vast areas of the world’s surface are covered by sand dunes these observations are not just of passing interest.
- Full Text:
- Date Issued: 2008
The Wesleyan Methodist Church in the Transvaal, 1823-1902
- Authors: Veysie, Donald Clifford
- Date: 1971
- Subjects: Methodist Church of Southern Africa Methodist Church of Southern Africa -- History Transvaal (South Africa) -- History -- To 1880 Transvaal (South Africa) -- History -- 1880-1910
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1234 , http://hdl.handle.net/10962/d1007463
- Description: From Preface: A preliminary survey of the history of the Wesleyan Methodist Church in the Transvaal revealed that the period of the early missions, before the formation of the Transvaal and Swaziland District, required research into the documents of other Districts for the purpose of writing a detailed history. It was therefore decided to confine research to the Documents of the Transvaal and Swaziland District and to write introductory chapters on the period of the early missions. The detailed research for this dissertation begins, therefore, with the creation of the Transvaal and Swaziland District in 1880. The natural point at which to finish appeared, at first, to be the beginning of the Second Transvaal War of Independence, but further research indicated that it would be more useful to conclude with the end of the war in 1902.
- Full Text:
- Date Issued: 1971
- Authors: Veysie, Donald Clifford
- Date: 1971
- Subjects: Methodist Church of Southern Africa Methodist Church of Southern Africa -- History Transvaal (South Africa) -- History -- To 1880 Transvaal (South Africa) -- History -- 1880-1910
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1234 , http://hdl.handle.net/10962/d1007463
- Description: From Preface: A preliminary survey of the history of the Wesleyan Methodist Church in the Transvaal revealed that the period of the early missions, before the formation of the Transvaal and Swaziland District, required research into the documents of other Districts for the purpose of writing a detailed history. It was therefore decided to confine research to the Documents of the Transvaal and Swaziland District and to write introductory chapters on the period of the early missions. The detailed research for this dissertation begins, therefore, with the creation of the Transvaal and Swaziland District in 1880. The natural point at which to finish appeared, at first, to be the beginning of the Second Transvaal War of Independence, but further research indicated that it would be more useful to conclude with the end of the war in 1902.
- Full Text:
- Date Issued: 1971
The voluntary welfare organisations of the Border and Transkei: a contribution to the sociology of social work
- Authors: Bettison, D G
- Date: 1956
- Subjects: Social service -- South Africa -- Transkei Social service -- South Africa -- Eastern Cape Volunteer workers in social service
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3314 , http://hdl.handle.net/10962/d1003102
- Description: This research is intended to examine the internal organisational structure of the existing [voluntary welfare] organisations to ascertain what relationship may prove effective between themselves and the [Border Local Welfare] Board. This aim introduced the need to ascertain whether a) the organisations in any town were connected with organisations in other towns or to a central administrative office either in the area of investigation or outside it; or b) the organisations of any town were simply ad hoc units unrelated to any other organisation or similar organisations elsewhere. If the latter were the case then the difficulty of co-ordination and representation on the Board could probably be no better arranged than an ad hoc system as at present. If, however, the former was the predominant pattern, then it would suggest other and more convenient means to the end in view. Fourthly, it was hoped to gain some knowledge of the fund raising methods of welfare organisations, the nature of the people controlling them, the attitudes of managing committees to social work, and what they thought a case work agency should do; and, lastly, some indication of the history of social work as practised by the voluntary agencies in the area of investigation. These latter topics were not intended to form the principal subject matter of the work. They have not been treated fully in the text, but the information gathered has been included in appropriate places throughout.
- Full Text:
- Date Issued: 1956
- Authors: Bettison, D G
- Date: 1956
- Subjects: Social service -- South Africa -- Transkei Social service -- South Africa -- Eastern Cape Volunteer workers in social service
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3314 , http://hdl.handle.net/10962/d1003102
- Description: This research is intended to examine the internal organisational structure of the existing [voluntary welfare] organisations to ascertain what relationship may prove effective between themselves and the [Border Local Welfare] Board. This aim introduced the need to ascertain whether a) the organisations in any town were connected with organisations in other towns or to a central administrative office either in the area of investigation or outside it; or b) the organisations of any town were simply ad hoc units unrelated to any other organisation or similar organisations elsewhere. If the latter were the case then the difficulty of co-ordination and representation on the Board could probably be no better arranged than an ad hoc system as at present. If, however, the former was the predominant pattern, then it would suggest other and more convenient means to the end in view. Fourthly, it was hoped to gain some knowledge of the fund raising methods of welfare organisations, the nature of the people controlling them, the attitudes of managing committees to social work, and what they thought a case work agency should do; and, lastly, some indication of the history of social work as practised by the voluntary agencies in the area of investigation. These latter topics were not intended to form the principal subject matter of the work. They have not been treated fully in the text, but the information gathered has been included in appropriate places throughout.
- Full Text:
- Date Issued: 1956
The vocal works of Olivier Messiaen
- Authors: Donkin, Deborah Jean
- Date: 1995
- Subjects: Messiaen, Olivier, 1908-1992 Vocal music -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2634 , http://hdl.handle.net/10962/d1002299
- Description: Olivier Messiaen's compositions for voice, though less widely known than his instrumental works, span some forty years and comprise a fifth of his total output. They have hitherto not been subject to much attention. A study of the elements comprising the vocal lines and accompanying instrumentation from the piano-voice song set, Trois melodies (1930), to the vast orchestral-choral La Transfiguration de Notre Seigneur Jesus-Chlist (1969) reveals, amongst other characteristic and evolving features, the emergence of a unique, simulated, plainchant style and its subsequent transformation into incantation with suitably modified accompaniment. While wide-ranging, chromatic and rhythmically free vocal lines are typical of many twentieth century compositions, Messiaen's use of such features is found to be novel, by virtue of the peculiar modal and temporal ambits within which he operated. Vocal delivery is progressively expanded from conventional bel canto production to humming, howling,and eventually speech and percussive sounds and reaches an apotheosis in the virtuoso effects of Cinq Rechants (1949). This recedes somewhat in La Transfiguration, which displays instead a wealth of hybrid plainsong-type writing. Choral works are interesting in that the emphasis shifts from standard part-writing to monody or accompanied unison singing, with an attendant absence of characterised solo parts. By constantly varying the colour of the single melodic line with different permutations of voice types, timbre assumes a new importance, particularly in La Transfiguration. The study of the texts, most of which were conceived by the composer simultaneously with the music, contributes much to the understanding of each work. Biblical symbolism in the early lyrics is progressively enriched by references to numerological, mythological and nature symbolism, mixed in an increasingly Surrealistic manner. The gradual incorporation of emotive phonemes in the texts, culminates in the invented language of Cinq Rechants. The thesis thus reveals an evolving yet persistently idiosyncratic vocal style, which establishes Messiaen as one of the most original composers of his time. It further demonstrates that his vocal works are an important component of his total oeuvre and also a significant contribution to twentieth century vocal literature.
- Full Text:
- Date Issued: 1995
- Authors: Donkin, Deborah Jean
- Date: 1995
- Subjects: Messiaen, Olivier, 1908-1992 Vocal music -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2634 , http://hdl.handle.net/10962/d1002299
- Description: Olivier Messiaen's compositions for voice, though less widely known than his instrumental works, span some forty years and comprise a fifth of his total output. They have hitherto not been subject to much attention. A study of the elements comprising the vocal lines and accompanying instrumentation from the piano-voice song set, Trois melodies (1930), to the vast orchestral-choral La Transfiguration de Notre Seigneur Jesus-Chlist (1969) reveals, amongst other characteristic and evolving features, the emergence of a unique, simulated, plainchant style and its subsequent transformation into incantation with suitably modified accompaniment. While wide-ranging, chromatic and rhythmically free vocal lines are typical of many twentieth century compositions, Messiaen's use of such features is found to be novel, by virtue of the peculiar modal and temporal ambits within which he operated. Vocal delivery is progressively expanded from conventional bel canto production to humming, howling,and eventually speech and percussive sounds and reaches an apotheosis in the virtuoso effects of Cinq Rechants (1949). This recedes somewhat in La Transfiguration, which displays instead a wealth of hybrid plainsong-type writing. Choral works are interesting in that the emphasis shifts from standard part-writing to monody or accompanied unison singing, with an attendant absence of characterised solo parts. By constantly varying the colour of the single melodic line with different permutations of voice types, timbre assumes a new importance, particularly in La Transfiguration. The study of the texts, most of which were conceived by the composer simultaneously with the music, contributes much to the understanding of each work. Biblical symbolism in the early lyrics is progressively enriched by references to numerological, mythological and nature symbolism, mixed in an increasingly Surrealistic manner. The gradual incorporation of emotive phonemes in the texts, culminates in the invented language of Cinq Rechants. The thesis thus reveals an evolving yet persistently idiosyncratic vocal style, which establishes Messiaen as one of the most original composers of his time. It further demonstrates that his vocal works are an important component of his total oeuvre and also a significant contribution to twentieth century vocal literature.
- Full Text:
- Date Issued: 1995
The vegetation potential of natural rangelands in the mid-Fish River Valley, Eastern Cape, South Africa: towards a sustainable and acceptable management system
- Birch, Natalie Vivienne Evans
- Authors: Birch, Natalie Vivienne Evans
- Date: 2001
- Subjects: Vegetation and climate -- South Africa -- Eastern Cape Vegetation dynamics -- South Africa -- Eastern Cape Vegetation surveys -- South Africa -- Eastern Cape Land -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4186 , http://hdl.handle.net/10962/d1003754
- Description: Desertification is the diminution or destruction of the biological potential of land, and can lead ultimately to desert-like conditions. The vegetation of southern Africa is claimed to have altered over the past 100 years and much of the change is attributed to pastoral practice. In recent years however there has been much debate around the issue of the deterioration and loss of productivity of the natural rangelands, specifically those under communal management. It is one thing to claim that the vegetation has changed but quite another to produce data and analyses to show this unequivocally. Furthermore it is generally difficult to determine the nature and extent of change in natural ecosystems, as one does not know what the optimal base-line conditions should be. For this reason emphasis has been placed on developing models of potential or expected vegetation. By comparing a model of potential or expected vegetation with that of the contemporary vegetation, areas that deviate from expectation can be identified, in so doing providing evidence of the direction of change in the rangelands under various management treatments. The objective of this study was to determine shifts in the vegetation under different land-use treatments, by developing a technique to predict the potential vegetation of an area. In order to explore the nature and extent of degradation at the landscape scale a study site was selected where a range of land-use and rangeland management practices could be studied in parallel. The mid-Fish River valley consists of three markedly different units of land management, namely commercial rangelands, communal rangelands and nature conservation areas. The vegetation within the mid-Fish River valley falls within the Thicket biome and consists of three main vegetation types namely, Short Succulent Thicket, Medium Succulent Thicket and Mesic Bushclump Savanna. The creation of this potential vegetation model was dependent on the direct gradient analysis approach of relating the community patterns with environmental variables. To achieve this, floristic information was collected at sites along a topographical-moisture gradient. A Canonical Correspondence Analysis (CCA) between the environmental variables and the plant communities produced a classification from which the conditions normally associated with the major plant communities were predicted. When projected as a digital map, the qualifying sites provided a testable hypothesis of the potential vegetation. The results of this study showed a definite grazing gradient, which reflects a change from a more mesic environment towards a more arid environment with an increase in utilisation pressure. The predictive vegetation model proved to be useful for predicting the occurrence of the valley thicket communities within the Eastern Cape.
- Full Text:
- Date Issued: 2001
- Authors: Birch, Natalie Vivienne Evans
- Date: 2001
- Subjects: Vegetation and climate -- South Africa -- Eastern Cape Vegetation dynamics -- South Africa -- Eastern Cape Vegetation surveys -- South Africa -- Eastern Cape Land -- South Africa -- Eastern Cape Rangelands -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4186 , http://hdl.handle.net/10962/d1003754
- Description: Desertification is the diminution or destruction of the biological potential of land, and can lead ultimately to desert-like conditions. The vegetation of southern Africa is claimed to have altered over the past 100 years and much of the change is attributed to pastoral practice. In recent years however there has been much debate around the issue of the deterioration and loss of productivity of the natural rangelands, specifically those under communal management. It is one thing to claim that the vegetation has changed but quite another to produce data and analyses to show this unequivocally. Furthermore it is generally difficult to determine the nature and extent of change in natural ecosystems, as one does not know what the optimal base-line conditions should be. For this reason emphasis has been placed on developing models of potential or expected vegetation. By comparing a model of potential or expected vegetation with that of the contemporary vegetation, areas that deviate from expectation can be identified, in so doing providing evidence of the direction of change in the rangelands under various management treatments. The objective of this study was to determine shifts in the vegetation under different land-use treatments, by developing a technique to predict the potential vegetation of an area. In order to explore the nature and extent of degradation at the landscape scale a study site was selected where a range of land-use and rangeland management practices could be studied in parallel. The mid-Fish River valley consists of three markedly different units of land management, namely commercial rangelands, communal rangelands and nature conservation areas. The vegetation within the mid-Fish River valley falls within the Thicket biome and consists of three main vegetation types namely, Short Succulent Thicket, Medium Succulent Thicket and Mesic Bushclump Savanna. The creation of this potential vegetation model was dependent on the direct gradient analysis approach of relating the community patterns with environmental variables. To achieve this, floristic information was collected at sites along a topographical-moisture gradient. A Canonical Correspondence Analysis (CCA) between the environmental variables and the plant communities produced a classification from which the conditions normally associated with the major plant communities were predicted. When projected as a digital map, the qualifying sites provided a testable hypothesis of the potential vegetation. The results of this study showed a definite grazing gradient, which reflects a change from a more mesic environment towards a more arid environment with an increase in utilisation pressure. The predictive vegetation model proved to be useful for predicting the occurrence of the valley thicket communities within the Eastern Cape.
- Full Text:
- Date Issued: 2001
The value of locally isolated freshwater micro-algae in toxicity testing for water resource management in South Africa
- Authors: Gola, Nontutuzelo Pearl
- Date: 2015
- Subjects: Microalgae -- South Africa , Toxicity testing , Water resources development -- South Africa , Aquatic habitats -- South Africa , Water -- Pollution -- Toxicology , Water quality management -- South Africa , Sewage disposal in rivers, lakes, etc. -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6049 , http://hdl.handle.net/10962/d1017873
- Description: The ecological position of micro-algae at the base of the aquatic food web makes them critical components of aquatic ecosystems. Their short generation time also makes them useful biological indicators because they respond quickly to changes in environmental condition, enabling timely identification and assessment of water quality changes. The inclusion of micro-algae as indicators in water resource regulation and management in South Africa has started recently, their more extensive use in biomonitoring and ecotoxicology programmes for water resource management would contribute to the South African policy if water resource protection. The standard algal growth inhibition assay with the species Pseudokirchneriella subcapitata is currently used for monitoring toxicity of in-stream and industrial wastewater discharges to freshwater micro-algae. The relevance of the data generated by standard toxicity bioassays has been questioned, since micro-algae in particular are extremely variable in their sensitivity to a range of contaminants and these standard species used may not occur in the local aquatic environment. As a result, international regulatory agencies, have recommended algal growth inhibition tests be changed from a single standard species to tests with a number of species. One recommendation, in addition to the use of standard toxicity tests, is the use of species isolated from the local environment which may be more relevant for assessing site specific impacts. This study investigated the value and application of locally isolated South African freshwater micro-algae in toxicity tests for water resource management and was carried out in three phases. The first phase involved isolating micro-algae from South African aquatic resources. Micro-algae suitable for toxicity testing were identified and selected using as set of criteria. Three (Scenedesmus bicaudatus, Chlorella sorokiniana and Chlorella vulgaris) out of eight successfully isolated species satisfied the prescribed selection criteria and these were selected as potential toxicity test species. The second phase focused on refining and adapting the existing algal toxicity test protocol (the algal growth inhibition assay) for use on the locally isolated algal species. The refinement of the test protocol was achieved by exposing the locally isolated species to reference toxicants in order to assess and compare their growth and sensitivity to the toxicants under the prescribed toxicity test conditions with that of the standard toxicity test species (Pseudokirchneriella subcapitata) and a commercial laboratory species (Chlorella protothecoides). During this phase, one of the three local species (Scenedesmus bicaudatus) was eliminated as a potential toxicity test species due to inconsistent growth. The third phase of the study involved assessing the sensitivity of the two remaining species (C. vulgaris and C. sorokiniana) to a range of toxicants (reference toxicants, salts, effluents and a herbicide) and comparing it to that of the standard toxicity test species P. subcapitata and C. protothecoides. The toxicants were selected based on their relative importance in the South African context, as well as the practicality of using these local micro-algae to routinely determine the impact of these toxicants on local aquatic resources. The growth of the four micro-algae was stimulated by the selected effluents. The standard toxicity test species P. subcapitata was ranked the most sensitive and of the four species to two reference toxicants and two inorganic salts. Chlorella sorokiniana was ranked the most sensitive of the three Chlorella species to two reference toxicants and two inorganic salts. The herbicide stimulated the growth of C. vulgaris while inhibiting the growth of the other species. Pseudokirchneriela subcapitata and C. sorokiniana showed high intra-specific variability in growth, which made it difficult to determine the effective concentrations of the herbicide and therefore compare the sensitivity of the species. This varied response of micro-algal species to toxicants may result in the biodiversity shifts in aquatic ecosystems, and also supports the recommendation of using a battery of different species to support more informed decisions in water resource management.
- Full Text:
- Date Issued: 2015
- Authors: Gola, Nontutuzelo Pearl
- Date: 2015
- Subjects: Microalgae -- South Africa , Toxicity testing , Water resources development -- South Africa , Aquatic habitats -- South Africa , Water -- Pollution -- Toxicology , Water quality management -- South Africa , Sewage disposal in rivers, lakes, etc. -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6049 , http://hdl.handle.net/10962/d1017873
- Description: The ecological position of micro-algae at the base of the aquatic food web makes them critical components of aquatic ecosystems. Their short generation time also makes them useful biological indicators because they respond quickly to changes in environmental condition, enabling timely identification and assessment of water quality changes. The inclusion of micro-algae as indicators in water resource regulation and management in South Africa has started recently, their more extensive use in biomonitoring and ecotoxicology programmes for water resource management would contribute to the South African policy if water resource protection. The standard algal growth inhibition assay with the species Pseudokirchneriella subcapitata is currently used for monitoring toxicity of in-stream and industrial wastewater discharges to freshwater micro-algae. The relevance of the data generated by standard toxicity bioassays has been questioned, since micro-algae in particular are extremely variable in their sensitivity to a range of contaminants and these standard species used may not occur in the local aquatic environment. As a result, international regulatory agencies, have recommended algal growth inhibition tests be changed from a single standard species to tests with a number of species. One recommendation, in addition to the use of standard toxicity tests, is the use of species isolated from the local environment which may be more relevant for assessing site specific impacts. This study investigated the value and application of locally isolated South African freshwater micro-algae in toxicity tests for water resource management and was carried out in three phases. The first phase involved isolating micro-algae from South African aquatic resources. Micro-algae suitable for toxicity testing were identified and selected using as set of criteria. Three (Scenedesmus bicaudatus, Chlorella sorokiniana and Chlorella vulgaris) out of eight successfully isolated species satisfied the prescribed selection criteria and these were selected as potential toxicity test species. The second phase focused on refining and adapting the existing algal toxicity test protocol (the algal growth inhibition assay) for use on the locally isolated algal species. The refinement of the test protocol was achieved by exposing the locally isolated species to reference toxicants in order to assess and compare their growth and sensitivity to the toxicants under the prescribed toxicity test conditions with that of the standard toxicity test species (Pseudokirchneriella subcapitata) and a commercial laboratory species (Chlorella protothecoides). During this phase, one of the three local species (Scenedesmus bicaudatus) was eliminated as a potential toxicity test species due to inconsistent growth. The third phase of the study involved assessing the sensitivity of the two remaining species (C. vulgaris and C. sorokiniana) to a range of toxicants (reference toxicants, salts, effluents and a herbicide) and comparing it to that of the standard toxicity test species P. subcapitata and C. protothecoides. The toxicants were selected based on their relative importance in the South African context, as well as the practicality of using these local micro-algae to routinely determine the impact of these toxicants on local aquatic resources. The growth of the four micro-algae was stimulated by the selected effluents. The standard toxicity test species P. subcapitata was ranked the most sensitive and of the four species to two reference toxicants and two inorganic salts. Chlorella sorokiniana was ranked the most sensitive of the three Chlorella species to two reference toxicants and two inorganic salts. The herbicide stimulated the growth of C. vulgaris while inhibiting the growth of the other species. Pseudokirchneriela subcapitata and C. sorokiniana showed high intra-specific variability in growth, which made it difficult to determine the effective concentrations of the herbicide and therefore compare the sensitivity of the species. This varied response of micro-algal species to toxicants may result in the biodiversity shifts in aquatic ecosystems, and also supports the recommendation of using a battery of different species to support more informed decisions in water resource management.
- Full Text:
- Date Issued: 2015
The use of response surface methodology and artificial neural networks for the establishment of a design space for a sustained release salbutamol sulphate formulation
- Authors: Chaibva, Faith Anesu
- Date: 2010
- Subjects: Salbutamol sulphate Artificial intelligence -- Medical applications Neural networks (Computer science) Response surfaces (Statistics) Pharmaceutical biotechnology -- Quality contro Drugs -- Design Pharmacokinetics Drugs -- Dosage forms Drugs -- Controlled release
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3845 , http://hdl.handle.net/10962/d1010432
- Description: Quality by Design (QbD) is a systematic approach that has been recommended as suitable for the development of quality pharmaceutical products. The QbD approach commences with the definition of a quality target drug profile and predetermined objectives that are then used to direct the formulation development process with an emphasis on understanding the pharmaceutical science and manufacturing principles that apply to a product. The design space is directly linked to the use of QbD for formulation development and is a multidimensional combination and interaction of input variables and process parameters that have been demonstrated to provide an assurance of quality. The objective of these studies was to apply the principles of QbD as a framework for the optimisation of a sustained release (SR) formulation of salbutamol sulphate (SBS), and for the establishment of a design space using Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). SBS is a short-acting ♭₂ agonist that is used for the management of asthma and chronic obstructive pulmonary disease (COPD). The use of a SR formulation of SBS may provide clinical benefits in the management of these respiratory disorders. Ashtalin®8 ER (Cipla Ltd., Mumbai, Maharashtra, India) was selected as a reference formulation for use in these studies. An Ishikawa or Cause and Effect diagram was used to determine the impact of formulation and process factors that have the potential to affect product quality. Key areas of concern that must be monitored include the raw materials, the manufacturing equipment and processes, and the analytical and assessment methods employed. The conditions in the laboratory and manufacturing processes were carefully monitored and recorded for any deviation from protocol, and equipment for assessment of dosage form performance, including dissolution equipment, balances and hardness testers, underwent regular maintenance. Preliminary studies to assess the potential utility of Methocel® Kl OOM, alone and in combination with other matrix forming polymers, revealed that the combination of this polymer with xanthan gum and Carbopol® has the potential to modulate the release of SBS at a specific rate, for a period of 12 hr. A central composite design using Methocel® KlOOM, xanthan gum, Carbopol® 974P and Surelease® as the granulating fluid was constructed to fully evaluate the impact of these formulation variables on the rate and extent of SBS release from manufactured formulations. The results revealed that although Methocel® KlOOM and xanthan gum had the greatest retardant effect on drug release, interactions between the polymers used in the study were also important determinants of the measureable responses. An ANN model was trained for optimisation using the data generated from a central composite study. The efficiency of the network was optimised by assessing the impact of the number of nodes in the hidden layer using a three layer Multi Layer Perceptron (MLP). The results revealed that a network with nine nodes in the hidden layer had the best predictive ability, suitable for application to formulation optimisation studies. Pharmaceutical optimisation was conducted using both the RSM and the trained ANN models. The results from the two optimisation procedures yielded two different formulation compositions that were subjected to in vitro dissolution testing using USP Apparatus 3. The results revealed that, although the formulation compositions that were derived from the optimisation procedures were different, both solutions gave reproducible results for which the dissolution profiles were indeed similar to that of the reference formulation. RSM and ANN were further investigated as possible means of establishing a design space for formulation compositions that would result in dosage forms that have similar in vitro release test profiles comparable to the reference product. Constraint plots were used to determine the bounds of the formulation variables that would result in the manufacture of dosage forms with the desired release profile. ANN simulations with hypothetical formulations that were generated within a small region of the experimental domain were investigated as a means of understanding the impact of varying the composition of the formulation on resultant dissolution profiles. Although both methods were suitable for the establishment of a design space, the use of ANN may be better suited for this purpose because of the manner in which ANN handles data. As more information about the behaviour of a formulation and its processes is generated during the product Iifecycle, ANN may be used to evaluate the impact of formulation and process variables on measureable responses. It is recommended that ANN may be suitable for the optimisation of pharmaceutical formulations and establishment of a design space in line with ICH Pharmaceutical Development [1], Quality Risk Management [2] and Pharmaceutical Quality Systems [3]
- Full Text:
- Date Issued: 2010
- Authors: Chaibva, Faith Anesu
- Date: 2010
- Subjects: Salbutamol sulphate Artificial intelligence -- Medical applications Neural networks (Computer science) Response surfaces (Statistics) Pharmaceutical biotechnology -- Quality contro Drugs -- Design Pharmacokinetics Drugs -- Dosage forms Drugs -- Controlled release
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3845 , http://hdl.handle.net/10962/d1010432
- Description: Quality by Design (QbD) is a systematic approach that has been recommended as suitable for the development of quality pharmaceutical products. The QbD approach commences with the definition of a quality target drug profile and predetermined objectives that are then used to direct the formulation development process with an emphasis on understanding the pharmaceutical science and manufacturing principles that apply to a product. The design space is directly linked to the use of QbD for formulation development and is a multidimensional combination and interaction of input variables and process parameters that have been demonstrated to provide an assurance of quality. The objective of these studies was to apply the principles of QbD as a framework for the optimisation of a sustained release (SR) formulation of salbutamol sulphate (SBS), and for the establishment of a design space using Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). SBS is a short-acting ♭₂ agonist that is used for the management of asthma and chronic obstructive pulmonary disease (COPD). The use of a SR formulation of SBS may provide clinical benefits in the management of these respiratory disorders. Ashtalin®8 ER (Cipla Ltd., Mumbai, Maharashtra, India) was selected as a reference formulation for use in these studies. An Ishikawa or Cause and Effect diagram was used to determine the impact of formulation and process factors that have the potential to affect product quality. Key areas of concern that must be monitored include the raw materials, the manufacturing equipment and processes, and the analytical and assessment methods employed. The conditions in the laboratory and manufacturing processes were carefully monitored and recorded for any deviation from protocol, and equipment for assessment of dosage form performance, including dissolution equipment, balances and hardness testers, underwent regular maintenance. Preliminary studies to assess the potential utility of Methocel® Kl OOM, alone and in combination with other matrix forming polymers, revealed that the combination of this polymer with xanthan gum and Carbopol® has the potential to modulate the release of SBS at a specific rate, for a period of 12 hr. A central composite design using Methocel® KlOOM, xanthan gum, Carbopol® 974P and Surelease® as the granulating fluid was constructed to fully evaluate the impact of these formulation variables on the rate and extent of SBS release from manufactured formulations. The results revealed that although Methocel® KlOOM and xanthan gum had the greatest retardant effect on drug release, interactions between the polymers used in the study were also important determinants of the measureable responses. An ANN model was trained for optimisation using the data generated from a central composite study. The efficiency of the network was optimised by assessing the impact of the number of nodes in the hidden layer using a three layer Multi Layer Perceptron (MLP). The results revealed that a network with nine nodes in the hidden layer had the best predictive ability, suitable for application to formulation optimisation studies. Pharmaceutical optimisation was conducted using both the RSM and the trained ANN models. The results from the two optimisation procedures yielded two different formulation compositions that were subjected to in vitro dissolution testing using USP Apparatus 3. The results revealed that, although the formulation compositions that were derived from the optimisation procedures were different, both solutions gave reproducible results for which the dissolution profiles were indeed similar to that of the reference formulation. RSM and ANN were further investigated as possible means of establishing a design space for formulation compositions that would result in dosage forms that have similar in vitro release test profiles comparable to the reference product. Constraint plots were used to determine the bounds of the formulation variables that would result in the manufacture of dosage forms with the desired release profile. ANN simulations with hypothetical formulations that were generated within a small region of the experimental domain were investigated as a means of understanding the impact of varying the composition of the formulation on resultant dissolution profiles. Although both methods were suitable for the establishment of a design space, the use of ANN may be better suited for this purpose because of the manner in which ANN handles data. As more information about the behaviour of a formulation and its processes is generated during the product Iifecycle, ANN may be used to evaluate the impact of formulation and process variables on measureable responses. It is recommended that ANN may be suitable for the optimisation of pharmaceutical formulations and establishment of a design space in line with ICH Pharmaceutical Development [1], Quality Risk Management [2] and Pharmaceutical Quality Systems [3]
- Full Text:
- Date Issued: 2010
The use of hydrological information to improve flood management-integrated hydrological modelling of the Zambezi River basin
- Vilanculos, Agostinho Chuquelane Fadulo
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
The use of Geographical Information Systems for the promotion of spatial cognition, spatial perspective taking and problem solving in school level geography
- Authors: Britz, Hendrina Wilhemina
- Date: 2013
- Subjects: Geography -- Study and teaching -- South Africa -- Port Elizabeth , Geographic information systems -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9579 , http://hdl.handle.net/10948/d1020298
- Description: A question asked at the United States of America (USA) National Council for Geographic Education (NCGE) conference in 1967, namely, what learning does GIS allow that other ways do not and whether teaching GIS at school level is worth the time and effort required to implement it, remains largely unanswered. Literature searches suggest that little more has been done since 1967 to investigate the effectiveness of GIS in education, or that there are any findings to suggest that GIS is worth the time and effort to implement in schools. Internationally the implementation of GIS software and geo-spatial data in schools has been slow, and South Africa is no exception. The main reasons given for slow implementation internationally have included lack of resources, lack of training and lack of time. The majority of secondary schools that offer Geography in the Port Elizabeth Education District, South Africa, teach GIS theory without the use of GIS software and geo-spatial data. The purpose of this research was to elicit the perceptions of secondary school level Geography teachers and learners of the benefits, barriers and obstacles to implementing GIS software and geo-spatial data as a teaching strategy. As a focused exercise to investigate what learning using GIS allows that other ways do not, this study also investigated whether using GIS as a teaching and learning strategy enables the promotion of learners spatial cognition, spatial perspective taking and problem solving abilities better than traditional methods do. The findings are viewed through the lens of developing Crystallized Intelligence (Gc), Spatial Intelligence (Gv) and Fluid Intelligence (Gf), respectively. The study followed a concurrent transformative mixed methods design with pre-post testing and the use of crossover experimental and control groups to generate both qualitative and quantitative data. Questionnaires aimed at all secondary Geography teachers in the Port Elizabeth Education District were used to assess how GIS is taught in their schools and to evaluate their perceptions of the benefits and barriers of implementing GIS software and geo-spatial data in the classroom. Four secondary school Geography teachers in four schools volunteered to take part in the experimental aspects of the study. Empirical data on the development of spatial cognition, spatial perspective taking, and problem solving were generated via pre- and post-tests in which the grade 11 Geography learners participated. Experimental and comparison groups of learners wrote four different types of pre- and post-tests where the experimental groups worked on GIS software with geo-spatial data while the comparison groups used traditional methods. Teacher interviews and learner interviews were also conducted to assess attitudes towards GIS software and geo-spatial data as a teaching strategy. The results from this aspect of the study mirrored the benefits and barriers to implementing GIS in schools recorded in international literature. However, and possibly more importantly, the empirical data generated by the learners revealed that GIS software and geo-spatial data do statistically significantly promote better spatial cognition (Crystallized Intelligence) and spatial perspective taking (Spatial Intelligence) than traditional methods do (i.e. using atlases, rulers and calculators). No improvement was found in the experimental groups‟ problem solving abilities. This report offers possible explanations and recommendations in terms of socio-cultural findings from other educational studies on the effects of exploratory talk on the development of Fluid Intelligence. Recommendations are made for the attention of curriculum developers, teachers, school principals, departmental officials and other educational stakeholders in terms of what is required for the successful implementation of GIS software and the use of geo-spatial data in secondary school Geography classes.
- Full Text:
- Date Issued: 2013
- Authors: Britz, Hendrina Wilhemina
- Date: 2013
- Subjects: Geography -- Study and teaching -- South Africa -- Port Elizabeth , Geographic information systems -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9579 , http://hdl.handle.net/10948/d1020298
- Description: A question asked at the United States of America (USA) National Council for Geographic Education (NCGE) conference in 1967, namely, what learning does GIS allow that other ways do not and whether teaching GIS at school level is worth the time and effort required to implement it, remains largely unanswered. Literature searches suggest that little more has been done since 1967 to investigate the effectiveness of GIS in education, or that there are any findings to suggest that GIS is worth the time and effort to implement in schools. Internationally the implementation of GIS software and geo-spatial data in schools has been slow, and South Africa is no exception. The main reasons given for slow implementation internationally have included lack of resources, lack of training and lack of time. The majority of secondary schools that offer Geography in the Port Elizabeth Education District, South Africa, teach GIS theory without the use of GIS software and geo-spatial data. The purpose of this research was to elicit the perceptions of secondary school level Geography teachers and learners of the benefits, barriers and obstacles to implementing GIS software and geo-spatial data as a teaching strategy. As a focused exercise to investigate what learning using GIS allows that other ways do not, this study also investigated whether using GIS as a teaching and learning strategy enables the promotion of learners spatial cognition, spatial perspective taking and problem solving abilities better than traditional methods do. The findings are viewed through the lens of developing Crystallized Intelligence (Gc), Spatial Intelligence (Gv) and Fluid Intelligence (Gf), respectively. The study followed a concurrent transformative mixed methods design with pre-post testing and the use of crossover experimental and control groups to generate both qualitative and quantitative data. Questionnaires aimed at all secondary Geography teachers in the Port Elizabeth Education District were used to assess how GIS is taught in their schools and to evaluate their perceptions of the benefits and barriers of implementing GIS software and geo-spatial data in the classroom. Four secondary school Geography teachers in four schools volunteered to take part in the experimental aspects of the study. Empirical data on the development of spatial cognition, spatial perspective taking, and problem solving were generated via pre- and post-tests in which the grade 11 Geography learners participated. Experimental and comparison groups of learners wrote four different types of pre- and post-tests where the experimental groups worked on GIS software with geo-spatial data while the comparison groups used traditional methods. Teacher interviews and learner interviews were also conducted to assess attitudes towards GIS software and geo-spatial data as a teaching strategy. The results from this aspect of the study mirrored the benefits and barriers to implementing GIS in schools recorded in international literature. However, and possibly more importantly, the empirical data generated by the learners revealed that GIS software and geo-spatial data do statistically significantly promote better spatial cognition (Crystallized Intelligence) and spatial perspective taking (Spatial Intelligence) than traditional methods do (i.e. using atlases, rulers and calculators). No improvement was found in the experimental groups‟ problem solving abilities. This report offers possible explanations and recommendations in terms of socio-cultural findings from other educational studies on the effects of exploratory talk on the development of Fluid Intelligence. Recommendations are made for the attention of curriculum developers, teachers, school principals, departmental officials and other educational stakeholders in terms of what is required for the successful implementation of GIS software and the use of geo-spatial data in secondary school Geography classes.
- Full Text:
- Date Issued: 2013
The tropical environment and malaria in southwestern Nigeria, 1861 – 1960
- Authors: Adetiba, Adedamola Seun
- Date: 2019
- Subjects: Diseases and history -- Africa , Diseases and history -- Nigeria , Medical anthropology -- Africa , Medical anthropology -- Nigeria , Malaria -- Social aspects -- Nigeria , Malaria -- Nigeria -- History , Nigeria -- History , Imperialism -- Health aspects , Medicine -- Colonies -- Great Britain -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76564 , vital:30605
- Description: This thesis is a social history of malaria in southwestern Nigeria. It contributes to the burgeoning literature in the historiography of medicine, specifically the medicine and empire debate. Key to the issues raised in this thesis is the extent to which the limitations in colonial medical policies, most especially malaria control programmes, inspired critical and ingenious responses from African nationalists, doctors, patients, research volunteers, and indigenous medical practitioners. Challenged by a wide range of diseases and a paucity of health facilities and disease control schemes, African rural dwellers became medical pluralists in the ways they imagined and appropriated ideas of Western medicine alongside their indigenous medical practices. Beginning with a detailed historical exploration of the issues that informed the introduction of curative and preventive medicine in southwestern Nigeria, this thesis reveals the focus of colonial medicine. It exposes the one-sided nature of medical services in colonial spaces like southwestern Nigeria and the ways it shaped multifaceted responses from Africans, who were specifically side-lined till the 1950s when the rural medical service scheme was introduced. The focus of colonial medicine is drawn from relatively rich but often subjective historical evidence, such as a plethora of official reports of the department of medical and sanitary services, official correspondences within the colonial government in Lagos and Nigeria, and between the colonial government and the colonial office in the United Kingdom. Details of African responses to medical policies were garnered from newspaper publications and correspondences between the African public and the colonial government in Lagos. They reveal very interesting details of the ways Africans imagined, reimagined, and appropriated malaria control ideas and schemes. The central argument in this thesis is that attempts to control malaria in southwestern Nigeria till the 1950s, were shaped by a single concern to ameliorate the implications of the disease on the colonial state. It argues that this one-sided nature of malaria control programme informed the basis for medical pluralism in most rural spaces where African communities became patrons and sponsors of Western medicine and at the same time custodians of their indigenous medical practices. The series of justifications for the sustenance of these services were reinforced on the basis of the failure of the colonial state to guarantee the health needs of their colonial subjects. The aim of the thesis is to reinforce arguments that portray colonial medicine as a “tool of empire” but goes a bit further to explain the extent to which Africans related to this reality. It states quite categorically that Africans were not docile and silent, but that they acted decisively in ways that suited their varied interests and courses.
- Full Text:
- Date Issued: 2019
- Authors: Adetiba, Adedamola Seun
- Date: 2019
- Subjects: Diseases and history -- Africa , Diseases and history -- Nigeria , Medical anthropology -- Africa , Medical anthropology -- Nigeria , Malaria -- Social aspects -- Nigeria , Malaria -- Nigeria -- History , Nigeria -- History , Imperialism -- Health aspects , Medicine -- Colonies -- Great Britain -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76564 , vital:30605
- Description: This thesis is a social history of malaria in southwestern Nigeria. It contributes to the burgeoning literature in the historiography of medicine, specifically the medicine and empire debate. Key to the issues raised in this thesis is the extent to which the limitations in colonial medical policies, most especially malaria control programmes, inspired critical and ingenious responses from African nationalists, doctors, patients, research volunteers, and indigenous medical practitioners. Challenged by a wide range of diseases and a paucity of health facilities and disease control schemes, African rural dwellers became medical pluralists in the ways they imagined and appropriated ideas of Western medicine alongside their indigenous medical practices. Beginning with a detailed historical exploration of the issues that informed the introduction of curative and preventive medicine in southwestern Nigeria, this thesis reveals the focus of colonial medicine. It exposes the one-sided nature of medical services in colonial spaces like southwestern Nigeria and the ways it shaped multifaceted responses from Africans, who were specifically side-lined till the 1950s when the rural medical service scheme was introduced. The focus of colonial medicine is drawn from relatively rich but often subjective historical evidence, such as a plethora of official reports of the department of medical and sanitary services, official correspondences within the colonial government in Lagos and Nigeria, and between the colonial government and the colonial office in the United Kingdom. Details of African responses to medical policies were garnered from newspaper publications and correspondences between the African public and the colonial government in Lagos. They reveal very interesting details of the ways Africans imagined, reimagined, and appropriated malaria control ideas and schemes. The central argument in this thesis is that attempts to control malaria in southwestern Nigeria till the 1950s, were shaped by a single concern to ameliorate the implications of the disease on the colonial state. It argues that this one-sided nature of malaria control programme informed the basis for medical pluralism in most rural spaces where African communities became patrons and sponsors of Western medicine and at the same time custodians of their indigenous medical practices. The series of justifications for the sustenance of these services were reinforced on the basis of the failure of the colonial state to guarantee the health needs of their colonial subjects. The aim of the thesis is to reinforce arguments that portray colonial medicine as a “tool of empire” but goes a bit further to explain the extent to which Africans related to this reality. It states quite categorically that Africans were not docile and silent, but that they acted decisively in ways that suited their varied interests and courses.
- Full Text:
- Date Issued: 2019
The trophic ecology of waterbirds in a small temperate estuary: a stable isotope and lipid tracer approach
- Authors: Hean, Jeffrey William
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54356 , vital:26557
- Description: Waterbirds are often overlooked as predators in aquatic ecosystems, despite the fact that waterbirds congregate in great numbers in and around waterways, notably estuaries. To fully appreciate the effect that aquatic feeding waterbird species may have on aquatic prey communities and the role that they play in estuarine food webs, stable isotopes and fatty acid profiles were employed to examine the seasonal diet of selected waterbirds in the Kowie Estuary, Eastern Cape Province, South Africa. Population counts were conducted every month for four seasons to examine the demography of waterbirds in the lower reaches of the estuary. The mean monthly energy consumption, along with dry matter intake of all waterbird species observed, were calculated and compared to similar estuaries in South Africa and elsewhere. Three duck species, one migrant sandpiper and one piscivore were selected for more detailed investigation at several temporal scales. This thesis has revealed that stable isotope analysis of waterbird tissues provides more informative data than fatty acid analysis for investigating waterbird diet and basal resource-tertiary consumer nutrient coupling. Stable δ15N and δ13C isotopes from several body tissues, in conjunction with SIAR models, were used to determine the seasonal diet of each waterbird species, while fatty acid profiles were investigated to examine the trophic transfer of fatty acids from basal resources to waterbird predators via the benthic fauna. Stable isotopes revealed that Cape Shoveller, Cape Teal and Yellow-Billed Duck shifted their diet over both long and short temporal scales, while the migratory Ruff and piscivorous Little Egret maintained a relatively consistent diet over time. Isopods, amphipods, copepods and Mysidacea were the main foods of all three duck species and the Ruff (>30%). Little Egret fed mainly on flathead mullet throughout the year. Fatty acid analysis revealed evidence for trophic transfer of specific fatty acids from basal resources to waterbirds in the Kowie Estuary but provided little information on seasonal diet of waterbirds. Waterbirds foraging in the Kowie Estuary appeared to shift their diet to coincide with resource abundance pulses, but also displayed seasonal dietary overlap. This study highlights the role that waterbirds play in aquatic food webs. The subject requires more attention so that we can better understand all the predatory drivers on aquatic communities.
- Full Text:
- Date Issued: 2016
- Authors: Hean, Jeffrey William
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54356 , vital:26557
- Description: Waterbirds are often overlooked as predators in aquatic ecosystems, despite the fact that waterbirds congregate in great numbers in and around waterways, notably estuaries. To fully appreciate the effect that aquatic feeding waterbird species may have on aquatic prey communities and the role that they play in estuarine food webs, stable isotopes and fatty acid profiles were employed to examine the seasonal diet of selected waterbirds in the Kowie Estuary, Eastern Cape Province, South Africa. Population counts were conducted every month for four seasons to examine the demography of waterbirds in the lower reaches of the estuary. The mean monthly energy consumption, along with dry matter intake of all waterbird species observed, were calculated and compared to similar estuaries in South Africa and elsewhere. Three duck species, one migrant sandpiper and one piscivore were selected for more detailed investigation at several temporal scales. This thesis has revealed that stable isotope analysis of waterbird tissues provides more informative data than fatty acid analysis for investigating waterbird diet and basal resource-tertiary consumer nutrient coupling. Stable δ15N and δ13C isotopes from several body tissues, in conjunction with SIAR models, were used to determine the seasonal diet of each waterbird species, while fatty acid profiles were investigated to examine the trophic transfer of fatty acids from basal resources to waterbird predators via the benthic fauna. Stable isotopes revealed that Cape Shoveller, Cape Teal and Yellow-Billed Duck shifted their diet over both long and short temporal scales, while the migratory Ruff and piscivorous Little Egret maintained a relatively consistent diet over time. Isopods, amphipods, copepods and Mysidacea were the main foods of all three duck species and the Ruff (>30%). Little Egret fed mainly on flathead mullet throughout the year. Fatty acid analysis revealed evidence for trophic transfer of specific fatty acids from basal resources to waterbirds in the Kowie Estuary but provided little information on seasonal diet of waterbirds. Waterbirds foraging in the Kowie Estuary appeared to shift their diet to coincide with resource abundance pulses, but also displayed seasonal dietary overlap. This study highlights the role that waterbirds play in aquatic food webs. The subject requires more attention so that we can better understand all the predatory drivers on aquatic communities.
- Full Text:
- Date Issued: 2016
The trophic and spatial ecology of a sympatric dasyatid community at a remote Atoll, Seychelles
- Authors: Elston, Chantel
- Date: 2019
- Subjects: Dasyatidae -- Seychelles -- Ecology , Rays (Fishes) -- Seychelles -- Ecology , Ecology -- Seychelles , Dasyatidae -- Seychelles -- Conservation , Pastinachus sephen , Urogymnus granulatus , Urogymnus asperrimus
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/95756 , vital:31196 , DOI https://doi.org/10.21504/10962/95756
- Description: Batoid populations are declining globally but the paucity of information makes management or conservation efforts difficult. Additionally, batoids are mesopredators and are hypothesised to play important ecological roles, but a comprehensive understanding of these roles is also limited. Therefore, information on batoid habitat use, foraging ecology, and resource partitioning is needed. St. Joseph Atoll is a relatively pristine ecosystem that hosts a sympatric dasyatid community (Pastinachus sephen, Urogymnus granulatus, and U. asperrimus). Passive acoustic telemetry identified high levels of long-term site affinity by both juvenile and adult dasyatids to St. Joseph Atoll. Dispersal from the atoll by larger juveniles was also evident. Juveniles displayed restricted horizontal movements in the atoll, but the extent of these movements differed seasonally. Stomach content and stable isotope analyses identified inter-specific prey partitioning (P. sephen juveniles were mollusc specialists and U. granulatus juveniles were crustacean specialists) and intra-specific prey partitioning. Juveniles were reliant upon a seagrass-based food web, whereas adults were reliant on phytoplankton-based food web. Adults fed at higher trophic levels compared to juveniles (mean of 4.6 and 3.4 respectively). Juvenile dasyatids preferentially selected the shallow reef at habitat of the atoll, where there was no evidence for inter-specific habitat partitioning (individuals co-occurred randomly with con-and hetero-specifics). Conversely, resident adults were more reliant on the deeper lagoon. Juveniles selected the reef at habitat likely because it provided refuge from predation and foraging opportunities. However, juveniles were also detected in the lagoon habitat and this appeared to be necessitated by physical factors as they were detected more frequently in the lagoon at low tides and when temperatures on the reef fats became too warm or too cold. All results together suggest that St. Joseph Atoll is a nursery area for these dasyatids. Juveniles may be limited by resources as prey was partitioned between species. However, top-down control by larger sharks was likely a significant influence on habitat selection, as was the physical effects of tide and temperature. Finally, St. Joseph Atoll is suitable for the designation of a Marine Protected Area, which would likely confer high conservation benefits to this dasyatid community.
- Full Text:
- Date Issued: 2019
- Authors: Elston, Chantel
- Date: 2019
- Subjects: Dasyatidae -- Seychelles -- Ecology , Rays (Fishes) -- Seychelles -- Ecology , Ecology -- Seychelles , Dasyatidae -- Seychelles -- Conservation , Pastinachus sephen , Urogymnus granulatus , Urogymnus asperrimus
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/95756 , vital:31196 , DOI https://doi.org/10.21504/10962/95756
- Description: Batoid populations are declining globally but the paucity of information makes management or conservation efforts difficult. Additionally, batoids are mesopredators and are hypothesised to play important ecological roles, but a comprehensive understanding of these roles is also limited. Therefore, information on batoid habitat use, foraging ecology, and resource partitioning is needed. St. Joseph Atoll is a relatively pristine ecosystem that hosts a sympatric dasyatid community (Pastinachus sephen, Urogymnus granulatus, and U. asperrimus). Passive acoustic telemetry identified high levels of long-term site affinity by both juvenile and adult dasyatids to St. Joseph Atoll. Dispersal from the atoll by larger juveniles was also evident. Juveniles displayed restricted horizontal movements in the atoll, but the extent of these movements differed seasonally. Stomach content and stable isotope analyses identified inter-specific prey partitioning (P. sephen juveniles were mollusc specialists and U. granulatus juveniles were crustacean specialists) and intra-specific prey partitioning. Juveniles were reliant upon a seagrass-based food web, whereas adults were reliant on phytoplankton-based food web. Adults fed at higher trophic levels compared to juveniles (mean of 4.6 and 3.4 respectively). Juvenile dasyatids preferentially selected the shallow reef at habitat of the atoll, where there was no evidence for inter-specific habitat partitioning (individuals co-occurred randomly with con-and hetero-specifics). Conversely, resident adults were more reliant on the deeper lagoon. Juveniles selected the reef at habitat likely because it provided refuge from predation and foraging opportunities. However, juveniles were also detected in the lagoon habitat and this appeared to be necessitated by physical factors as they were detected more frequently in the lagoon at low tides and when temperatures on the reef fats became too warm or too cold. All results together suggest that St. Joseph Atoll is a nursery area for these dasyatids. Juveniles may be limited by resources as prey was partitioned between species. However, top-down control by larger sharks was likely a significant influence on habitat selection, as was the physical effects of tide and temperature. Finally, St. Joseph Atoll is suitable for the designation of a Marine Protected Area, which would likely confer high conservation benefits to this dasyatid community.
- Full Text:
- Date Issued: 2019
The Trope of the Child: Rereading Trauma, Subjectivity and Embodiment in Contemporary Child-Centred African Narratives by Ahmadou Kourouma, Chris Abani, K. Sello Duiker and Yvonne Vera
- Authors: Njovane, Thandokazi
- Date: 2019
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164557 , vital:41134 , doi:10.21504/10962/164557
- Description: Thesis (PhD)--Rhodes University, Humanities, Literary Studies in English, 2019
- Full Text:
- Date Issued: 2019
- Authors: Njovane, Thandokazi
- Date: 2019
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164557 , vital:41134 , doi:10.21504/10962/164557
- Description: Thesis (PhD)--Rhodes University, Humanities, Literary Studies in English, 2019
- Full Text:
- Date Issued: 2019
The transport system of the Border : a study of transport and communications in the Border region of the Cape Province with special reference to the effect of transport on the economic and commercial development of the region
- Authors: Smith, Hugh Hamilton
- Date: 1959
- Subjects: Transportation -- South Africa -- Eastern Cape , Harbors -- South Africa -- East London , Railroads -- South Africa -- Eastern Cape , Transportation, Automotive -- South Africa -- Eastern Cape , Communication and traffic -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1122 , http://hdl.handle.net/10962/d1018721
- Description: Transport undoubtedly occupies a most important place in the economic and commercial life of all countries. In this respect South Africa is no exception, and very briefly, the principal economic functions of transport are enumerated below. 1. Transport establishes communication between consumers and the producers of goods or services. 2. Transport facilitates the movement of persons between the place where they live and the place where they work - usually this is a daily procedure, but in South Africa it also entails the movement of large numbers of Natives from the Native Reserves to work for some months at a time either in the gold mines or in the several urban areas of the Union. 3. Transport makes geographical specialization possible, for agricultural or mineral resources will only be exploited, or specialized industries established, in a particular area, if the commodities produced can be transported to other parts of a country, or the world; and other capital and consumer goods brought to the producers living in the area of specialized production. 4. Transport faciitates industrial production because, of raw materials which come from many sources. Furthermore, transport enables the finished products of industry to be distributed to the markets in which they are sold. In all these cases, the efficiency of transport has to be measured not only in terms of its cost, but also in terms of its efficiency, which includes, inter alia, the time taken, the frequency of services, the safety of goods and passengers while in transit and the provision of various special services, such as the provision by railway undertakings of private siding facilities. This thesis will be divided into five parts, the first dealing with the technical and commercial development of the Buffalo Harbour. It has been decided to deal with the Harbour first because, not only has it been the focal point of the transport system of the Border Region since the latter part of the nineteenth century, but it has dominated the economic and commercial development of East London, as well as that of the Border Region as a whole. The second part deals with the evolution of the railway system from the 166 mile long East London and Queenstown Railway, to the present 1,110 miles of the Cape Eastern System. This historical chapter is followed by an analysis of the traffic of the Cape Eastern System. Part Three deals with the theory, practice, and economic consequences, of railway rating policy. Part Four is a detailed analysis of the goods traffic forwarded from, and received at East London in the period from 1st April, 1953 to 31st March, 1956. Part Five deals with roads and road transport. Finally, certain conclusions are offered, based on the significant points revealed by the investigation on which this thesis is based. In this thesis the theory of transport will not be dealt with in detail for it is essentially a factual account of the development of the transport system of the Border Region and an analysis of the present situation. It has unfortunately not been possible to make in this thesis a study of railway finance or railway economics with regard to the Cape Eastern System, for the data upon which to base such an investigation are not available for the Cape Eastern System in isolation. No attempt will be made to assess either the technical or the operating efficiency of the railway system for not only would this require more data than are available, but also a technical knowledge not possessed by the writer.
- Full Text:
- Date Issued: 1959
- Authors: Smith, Hugh Hamilton
- Date: 1959
- Subjects: Transportation -- South Africa -- Eastern Cape , Harbors -- South Africa -- East London , Railroads -- South Africa -- Eastern Cape , Transportation, Automotive -- South Africa -- Eastern Cape , Communication and traffic -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1122 , http://hdl.handle.net/10962/d1018721
- Description: Transport undoubtedly occupies a most important place in the economic and commercial life of all countries. In this respect South Africa is no exception, and very briefly, the principal economic functions of transport are enumerated below. 1. Transport establishes communication between consumers and the producers of goods or services. 2. Transport facilitates the movement of persons between the place where they live and the place where they work - usually this is a daily procedure, but in South Africa it also entails the movement of large numbers of Natives from the Native Reserves to work for some months at a time either in the gold mines or in the several urban areas of the Union. 3. Transport makes geographical specialization possible, for agricultural or mineral resources will only be exploited, or specialized industries established, in a particular area, if the commodities produced can be transported to other parts of a country, or the world; and other capital and consumer goods brought to the producers living in the area of specialized production. 4. Transport faciitates industrial production because, of raw materials which come from many sources. Furthermore, transport enables the finished products of industry to be distributed to the markets in which they are sold. In all these cases, the efficiency of transport has to be measured not only in terms of its cost, but also in terms of its efficiency, which includes, inter alia, the time taken, the frequency of services, the safety of goods and passengers while in transit and the provision of various special services, such as the provision by railway undertakings of private siding facilities. This thesis will be divided into five parts, the first dealing with the technical and commercial development of the Buffalo Harbour. It has been decided to deal with the Harbour first because, not only has it been the focal point of the transport system of the Border Region since the latter part of the nineteenth century, but it has dominated the economic and commercial development of East London, as well as that of the Border Region as a whole. The second part deals with the evolution of the railway system from the 166 mile long East London and Queenstown Railway, to the present 1,110 miles of the Cape Eastern System. This historical chapter is followed by an analysis of the traffic of the Cape Eastern System. Part Three deals with the theory, practice, and economic consequences, of railway rating policy. Part Four is a detailed analysis of the goods traffic forwarded from, and received at East London in the period from 1st April, 1953 to 31st March, 1956. Part Five deals with roads and road transport. Finally, certain conclusions are offered, based on the significant points revealed by the investigation on which this thesis is based. In this thesis the theory of transport will not be dealt with in detail for it is essentially a factual account of the development of the transport system of the Border Region and an analysis of the present situation. It has unfortunately not been possible to make in this thesis a study of railway finance or railway economics with regard to the Cape Eastern System, for the data upon which to base such an investigation are not available for the Cape Eastern System in isolation. No attempt will be made to assess either the technical or the operating efficiency of the railway system for not only would this require more data than are available, but also a technical knowledge not possessed by the writer.
- Full Text:
- Date Issued: 1959
The transitional role of the Xhosa oral poet in contemporary South African society
- Authors: Kaschula, Russell H
- Date: 1991
- Subjects: Folk poetry, Xhosa Xhosa (African people) -- Religion Xhosa (African people) -- Social life and customs Xhosa poetry Laudatory poetry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3563 , http://hdl.handle.net/10962/d1002085 , https://orcid.org/0000-0002-5481-6748
- Description: This thesis outlines the changing role of the Xhosa imbongi in contemporary South African society. The changing socio-economic and political scenario in South Africa, and the way in which the imbongi is adapting in order to accommodate new pressures created by these changes, form an integral part of this thesis. The effects of education and increasing literacy on the tradition are outlined. The interaction between oral and written forms is explored in chapter 2. The role of the imbongi within the religious sphere is included in chapter 3. Xhosa preachers within the independent churches often make use of the styles and techniques associated with oral poetry. Iimbongi who are not necessarily preachers also operate within this context. The relationship between the Congress of South African Trade Unions, the African National Congress and iimbongi has also been researched and forms part of chapters 4, 5, and the epilogue. The modern imbongi is drawn towards powerful organisations offering alternative leadership to many of the traditional chiefs. In the epilogue collected poetry is analysed in the context of Mandela's visit to Transkei in April 1990. Interviews have been conducted with chiefs, iimbongi attached to chiefs as well as those attached to different organisations. Poetry has been collected and analysed. In chapter 5, three case studies of modern iimbongi are included. The problems facing these iimbongi in their different contexts, as well as the power bases from which they draw, are outlined. Finally, an alternative definition of the imbongi is offered in the conclusion
- Full Text:
- Date Issued: 1991
- Authors: Kaschula, Russell H
- Date: 1991
- Subjects: Folk poetry, Xhosa Xhosa (African people) -- Religion Xhosa (African people) -- Social life and customs Xhosa poetry Laudatory poetry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3563 , http://hdl.handle.net/10962/d1002085 , https://orcid.org/0000-0002-5481-6748
- Description: This thesis outlines the changing role of the Xhosa imbongi in contemporary South African society. The changing socio-economic and political scenario in South Africa, and the way in which the imbongi is adapting in order to accommodate new pressures created by these changes, form an integral part of this thesis. The effects of education and increasing literacy on the tradition are outlined. The interaction between oral and written forms is explored in chapter 2. The role of the imbongi within the religious sphere is included in chapter 3. Xhosa preachers within the independent churches often make use of the styles and techniques associated with oral poetry. Iimbongi who are not necessarily preachers also operate within this context. The relationship between the Congress of South African Trade Unions, the African National Congress and iimbongi has also been researched and forms part of chapters 4, 5, and the epilogue. The modern imbongi is drawn towards powerful organisations offering alternative leadership to many of the traditional chiefs. In the epilogue collected poetry is analysed in the context of Mandela's visit to Transkei in April 1990. Interviews have been conducted with chiefs, iimbongi attached to chiefs as well as those attached to different organisations. Poetry has been collected and analysed. In chapter 5, three case studies of modern iimbongi are included. The problems facing these iimbongi in their different contexts, as well as the power bases from which they draw, are outlined. Finally, an alternative definition of the imbongi is offered in the conclusion
- Full Text:
- Date Issued: 1991
The training of artisans for house building projects in South Western Nigeria
- Authors: Oni, Oluwole Joseph
- Date: 2014
- Subjects: Skilled labor -- Nigeria , Artisans -- Training of -- Nigeria , Construction industry -- Employees -- Training of -- Nigeria , Training needs -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9726 , http://hdl.handle.net/10948/d1020625
- Description: The current shortage of artisans in the Nigerian house construction sector has constrained the productivity of the sector and exacerbated the nation‟s housing problem. The persistent neglect of the artisan training system has negatively impacted on the stock of artisans available for house construction projects. Nigeria‟s large and fast-growing population of over 140 million with an estimated growth rate of 3.2 percent has engendered increased investment in shelter provision; especially by individuals and families due to fast rising housing rentals- mainly in the urban centres. Past policies have not adequately addressed the realities of the skills crisis occasioned by inadequate and neglected apprenticeship training and poorly developed vocational education and training systems. The fallout of this is manifested in the difficulties faced by developers in sourcing suitably qualified and experienced artisans for house construction projects. In response to this challenge, an upsurge of migrant artisans and craftsmen from neighbouring West African nations like Togo, Benin Republic and Ghana to Nigeria has occurred in the recent times. They were attracted by building contracting firms to fill the gap created by inadequate artisan supply that is currently being experienced locally. This development is totally unacceptable as it exacerbates the overarching socio-economic problems in Nigeria, especially the already high unemployment rate which is estimated to be 23.9 percent. This study has consequently investigated the inadequate training of house construction artisans in South Western Nigeria; evolving interventions and developing a strategic model for improving the artisan training system to ensure an adequate and sustainable artisan supply in the house construction sector. The model incorporates best practices, rethinking strategies and integrated approaches in mitigating the identified challenges. The model is underpinned by reviewed literature and empirical findings. Quantitative surveys and interviews were utilised as the data sources. The research findings show that the factors which negatively impact on the artisan training system in the house construction sector include: the poor image of artisans in society; lack of recruitment strategies for attracting potential artisans; inadequate policy framework for training and employment; a faulty and rigid National Qualification Framework (NQF); the non-participation of employers in training; a poor funding mechanism; a weak regulatory framework and corrupt practices in training administration. Recommendations for addressing the inadequate training of artisans include education policy reforms to give priority to vocational education; a new regime of funding for vocational education and training; a review of the National Qualification Framework to integrate the vocational colleges with the university system; a reform of the regulatory framework; public re-orientation on the societal image of the artisans; adoption of a new approach of public- private partnership in artisan training; the provision of incentives schemes to attract potential artisans and the appropriation of the proposed model for an integrated approach to addressing the challenges.
- Full Text:
- Date Issued: 2014
- Authors: Oni, Oluwole Joseph
- Date: 2014
- Subjects: Skilled labor -- Nigeria , Artisans -- Training of -- Nigeria , Construction industry -- Employees -- Training of -- Nigeria , Training needs -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9726 , http://hdl.handle.net/10948/d1020625
- Description: The current shortage of artisans in the Nigerian house construction sector has constrained the productivity of the sector and exacerbated the nation‟s housing problem. The persistent neglect of the artisan training system has negatively impacted on the stock of artisans available for house construction projects. Nigeria‟s large and fast-growing population of over 140 million with an estimated growth rate of 3.2 percent has engendered increased investment in shelter provision; especially by individuals and families due to fast rising housing rentals- mainly in the urban centres. Past policies have not adequately addressed the realities of the skills crisis occasioned by inadequate and neglected apprenticeship training and poorly developed vocational education and training systems. The fallout of this is manifested in the difficulties faced by developers in sourcing suitably qualified and experienced artisans for house construction projects. In response to this challenge, an upsurge of migrant artisans and craftsmen from neighbouring West African nations like Togo, Benin Republic and Ghana to Nigeria has occurred in the recent times. They were attracted by building contracting firms to fill the gap created by inadequate artisan supply that is currently being experienced locally. This development is totally unacceptable as it exacerbates the overarching socio-economic problems in Nigeria, especially the already high unemployment rate which is estimated to be 23.9 percent. This study has consequently investigated the inadequate training of house construction artisans in South Western Nigeria; evolving interventions and developing a strategic model for improving the artisan training system to ensure an adequate and sustainable artisan supply in the house construction sector. The model incorporates best practices, rethinking strategies and integrated approaches in mitigating the identified challenges. The model is underpinned by reviewed literature and empirical findings. Quantitative surveys and interviews were utilised as the data sources. The research findings show that the factors which negatively impact on the artisan training system in the house construction sector include: the poor image of artisans in society; lack of recruitment strategies for attracting potential artisans; inadequate policy framework for training and employment; a faulty and rigid National Qualification Framework (NQF); the non-participation of employers in training; a poor funding mechanism; a weak regulatory framework and corrupt practices in training administration. Recommendations for addressing the inadequate training of artisans include education policy reforms to give priority to vocational education; a new regime of funding for vocational education and training; a review of the National Qualification Framework to integrate the vocational colleges with the university system; a reform of the regulatory framework; public re-orientation on the societal image of the artisans; adoption of a new approach of public- private partnership in artisan training; the provision of incentives schemes to attract potential artisans and the appropriation of the proposed model for an integrated approach to addressing the challenges.
- Full Text:
- Date Issued: 2014
The tonology of Xhosa
- Authors: Claughton, John Sellick
- Date: 1992
- Subjects: Xhosa language -- Tone
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3596 , http://hdl.handle.net/10962/d1002171
- Description: This thesis is an examination of the tonology of Xhosa. After an initial survey of the surface tones of the language, and a review of previous studies of Xhosa tone, a description is given of the major tonal patterns of Xhosa noun and verb morphology. In the course of this description the major tonologica1 rules are allowed to emerge. In particular it is shown that some of these rules lead to complex patterns of variation in the pronunciation of the same individual. The derivation of the tone patterns of adjectives and relatives is discussed and it is shown that these tone patterns offer partial support for the derivation of some adjective and relative constructions as derived from embedded sentences but also support for deriving simple attributive adjective constructions by means of phrase structure rules. Some interesting tonal patterns such as that shown by reduplicated stems are then explored. The tones of loan words are then investigated and evidence for the identification of English and Afrikaans stress with high tones by Xhosa speakers is adduced. In the final chapter certain general problems of Xhosa tone are discussed. In particular it is argued that attempts to interpret the tonal system in terms of an accent are unrevealing and also it is suggested that attempts to unify the various rules that spread tones to the right are mistaken. In the appendices a comprehensive survey of the tones of Xhosa inflections is given together with a substantial list of Xhosa words with the tones marked.
- Full Text:
- Date Issued: 1992
- Authors: Claughton, John Sellick
- Date: 1992
- Subjects: Xhosa language -- Tone
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3596 , http://hdl.handle.net/10962/d1002171
- Description: This thesis is an examination of the tonology of Xhosa. After an initial survey of the surface tones of the language, and a review of previous studies of Xhosa tone, a description is given of the major tonal patterns of Xhosa noun and verb morphology. In the course of this description the major tonologica1 rules are allowed to emerge. In particular it is shown that some of these rules lead to complex patterns of variation in the pronunciation of the same individual. The derivation of the tone patterns of adjectives and relatives is discussed and it is shown that these tone patterns offer partial support for the derivation of some adjective and relative constructions as derived from embedded sentences but also support for deriving simple attributive adjective constructions by means of phrase structure rules. Some interesting tonal patterns such as that shown by reduplicated stems are then explored. The tones of loan words are then investigated and evidence for the identification of English and Afrikaans stress with high tones by Xhosa speakers is adduced. In the final chapter certain general problems of Xhosa tone are discussed. In particular it is argued that attempts to interpret the tonal system in terms of an accent are unrevealing and also it is suggested that attempts to unify the various rules that spread tones to the right are mistaken. In the appendices a comprehensive survey of the tones of Xhosa inflections is given together with a substantial list of Xhosa words with the tones marked.
- Full Text:
- Date Issued: 1992