Household, production and the organisation of cooperative labour in Shixini, Transkei
- Authors: Heron, Gavin Stewart
- Date: 1990
- Subjects: Xhosa (African people) , Agriculture -- South Africa -- Transkei , Agriculture, Cooperative -- South Africa -- Transkei , Cooperative societies -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2109 , http://hdl.handle.net/10962/d1007448 , Xhosa (African people) , Agriculture -- South Africa -- Transkei , Agriculture, Cooperative -- South Africa -- Transkei , Cooperative societies -- South Africa -- Transkei
- Description: Incidences of cooperation in agricultural activity are widespread phenomena in low-income third world communities. Two forms of cooperative labour groupings are identified in Shixini, Transkei . These are the work party and the ploughing company. It is argued that different organisational principles operate in the different cooperative forms. Work parties are based on principles of neighbourhood whi Ie ploughing companies are organised around kinship relationships. Factors which determine the principle of organisation are social values; the wider South African economic system; ecology; reciprocity; the constitution and structure of the household; economic differentiation; and labour demand and supply. The dissertation is divided into five chapters. The first is an overview of the Shixini social, economic and political systems. This chapter discusses the influence of the wider South African politico-economic system on agricultural production; the Shixini!Transkei political context; kinship and its relation to social organisation; and the likely effects of an agricultural 'betterment' scheme on the area. The second chapter is an overview of agricultural production in Shixini. It is found that the most significant determinants of agricultural production is the structure and constitution of the household and the way in which stock is distributed in the community. The third and fourth chapters describe and analyse Xhosa work parties and ploughing companies . Argument is lead as to the reasons for the specific organisational principles operating in each case. The penultimate chapter is an analysis of sacred and secular ritual. It is argued that both ritual forms reveal cooperative principles of organisation. Secular ritual dramatises the organisation of work parties while sacred ritual dramatises kinship relationships and so, the organisation of ploughing companies. , KMBT_363
- Full Text:
- Date Issued: 1990
- Authors: Heron, Gavin Stewart
- Date: 1990
- Subjects: Xhosa (African people) , Agriculture -- South Africa -- Transkei , Agriculture, Cooperative -- South Africa -- Transkei , Cooperative societies -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2109 , http://hdl.handle.net/10962/d1007448 , Xhosa (African people) , Agriculture -- South Africa -- Transkei , Agriculture, Cooperative -- South Africa -- Transkei , Cooperative societies -- South Africa -- Transkei
- Description: Incidences of cooperation in agricultural activity are widespread phenomena in low-income third world communities. Two forms of cooperative labour groupings are identified in Shixini, Transkei . These are the work party and the ploughing company. It is argued that different organisational principles operate in the different cooperative forms. Work parties are based on principles of neighbourhood whi Ie ploughing companies are organised around kinship relationships. Factors which determine the principle of organisation are social values; the wider South African economic system; ecology; reciprocity; the constitution and structure of the household; economic differentiation; and labour demand and supply. The dissertation is divided into five chapters. The first is an overview of the Shixini social, economic and political systems. This chapter discusses the influence of the wider South African politico-economic system on agricultural production; the Shixini!Transkei political context; kinship and its relation to social organisation; and the likely effects of an agricultural 'betterment' scheme on the area. The second chapter is an overview of agricultural production in Shixini. It is found that the most significant determinants of agricultural production is the structure and constitution of the household and the way in which stock is distributed in the community. The third and fourth chapters describe and analyse Xhosa work parties and ploughing companies . Argument is lead as to the reasons for the specific organisational principles operating in each case. The penultimate chapter is an analysis of sacred and secular ritual. It is argued that both ritual forms reveal cooperative principles of organisation. Secular ritual dramatises the organisation of work parties while sacred ritual dramatises kinship relationships and so, the organisation of ploughing companies. , KMBT_363
- Full Text:
- Date Issued: 1990
Immunolocalisation of, and ultrastructural changes in the LH gonadotropes of Miniopterus schreibersii and Rhinolophus capensis (Mammalia: Chiroptera) in relation to their reproductive cycles
- Authors: Bojarski, Christina
- Date: 1990
- Subjects: Bats -- Reproduction
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5589 , http://hdl.handle.net/10962/d1002039
- Description: LH gonadotropes are successfully identified in the anterior pituitary of Minioptems schreibersii and Rhinolophus capensis, using immunogold labelling at the light and electron microscopy level. The gonadotropes are oval to polygonal in shape and possess numerous small secretory granules, which contain LH throughout the year. Their distribution is similar in both species, although the abundance varies slightly between species and sexes. Seasonal changes are detected in gonadotrope ultrastructure, pituitary LH levels, and plasma hormone levels, and activity pattern of LH gonadotropes generally coincide with reproductive activity in both bat species. In female M. schreibersii gonadotrope activity, pituitary LH, and plasma LH levels coincide with development, implantation and gestation. During the delayed implantation gonadotropes are inactive and and high follicular period of plasma LH levels are low, coinciding with corpus luteum inactivity and low plasma progesterone levels. Implantation coincides with increased activity of the gonadotrope activity, increased plasma LH levels, reactivation of the corpus luteum and elevated plasma progesterone levels. Activation of LH gonadotropes towards the end of hibernation may be initiated by the winter solstice, which marks the change to increasing daylength. In female R capensis gonadotrope activity and high pituitary and plasma LH levels occur towards the end of follicular development. During hibernation gonadotrope activity and plasma LH levels decrease. Ovulation coincides with increasing gonadotrope activity (which follows the winter solstice), although a preovulatory peak in plasma LH is not detected. In male M. schreibersii and R. capensis, gonadotrope activity and high plasma LH and testosterone levels coincide with spermatogenesis, except during a period of reproductive inactivity in spring in male M. schreibersii, where gonadotropes appear active and plasma LH and testosterone levels are high. The reason for this apparent activity is not known. Male sperm storage during hibernation in male R. capensis coincides with low gonadotrope activity and low plasma LH and testosterone levels. Factors initiating gonadotrope activity and hence spermatogenesis are probably decreasing daylength (summer solstice) in M. schreibersii and increasing ambient temperatures and food abundance (following the hibernation period) in R.capensis.
- Full Text:
- Date Issued: 1990
- Authors: Bojarski, Christina
- Date: 1990
- Subjects: Bats -- Reproduction
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5589 , http://hdl.handle.net/10962/d1002039
- Description: LH gonadotropes are successfully identified in the anterior pituitary of Minioptems schreibersii and Rhinolophus capensis, using immunogold labelling at the light and electron microscopy level. The gonadotropes are oval to polygonal in shape and possess numerous small secretory granules, which contain LH throughout the year. Their distribution is similar in both species, although the abundance varies slightly between species and sexes. Seasonal changes are detected in gonadotrope ultrastructure, pituitary LH levels, and plasma hormone levels, and activity pattern of LH gonadotropes generally coincide with reproductive activity in both bat species. In female M. schreibersii gonadotrope activity, pituitary LH, and plasma LH levels coincide with development, implantation and gestation. During the delayed implantation gonadotropes are inactive and and high follicular period of plasma LH levels are low, coinciding with corpus luteum inactivity and low plasma progesterone levels. Implantation coincides with increased activity of the gonadotrope activity, increased plasma LH levels, reactivation of the corpus luteum and elevated plasma progesterone levels. Activation of LH gonadotropes towards the end of hibernation may be initiated by the winter solstice, which marks the change to increasing daylength. In female R capensis gonadotrope activity and high pituitary and plasma LH levels occur towards the end of follicular development. During hibernation gonadotrope activity and plasma LH levels decrease. Ovulation coincides with increasing gonadotrope activity (which follows the winter solstice), although a preovulatory peak in plasma LH is not detected. In male M. schreibersii and R. capensis, gonadotrope activity and high plasma LH and testosterone levels coincide with spermatogenesis, except during a period of reproductive inactivity in spring in male M. schreibersii, where gonadotropes appear active and plasma LH and testosterone levels are high. The reason for this apparent activity is not known. Male sperm storage during hibernation in male R. capensis coincides with low gonadotrope activity and low plasma LH and testosterone levels. Factors initiating gonadotrope activity and hence spermatogenesis are probably decreasing daylength (summer solstice) in M. schreibersii and increasing ambient temperatures and food abundance (following the hibernation period) in R.capensis.
- Full Text:
- Date Issued: 1990
Initial findings of an investigation into the feasibility of a low level image processing workstation using transputers
- Authors: Cooke, Nicholas Duncan
- Date: 1990 , 2013-02-07
- Subjects: Image processing , Computer graphics , Fourier transformations -- Data processing , Transputers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4679 , http://hdl.handle.net/10962/d1006702 , Image processing , Computer graphics , Fourier transformations -- Data processing , Transputers
- Description: From Introduction: The research concentrates primarily on a feasibility study involving the setting up of an image processing workstation. As broad as this statement concerning the workstation may seem, there are several factors limiting the extent of the research. This project is not concerned with the design and implementation of a fully-fledged image processing workstation. Rather, it concerns an initial feasibility study of such a workstation, centered on the theme image processing aided by the parallel processing paradigm. In looking at the hardware available for the project, in the context of an image processing environment, a large amount of initial investigation was required prior to that concerned with the transputer and parallel processing. Work was done on the capturing and displaying of images. This formed a vital part of the project. Furthermore, considering that a new architecture was being used as the work horse within a conventional host architecture, the INTEL 80286, several aspects of the host architecture had also to be investigated. These included the actual processing capabilities of the host, the capturing and storing of the images on the host, and most importantly, the interface between the host and the transputer [C0089]. Benchmarking was important in order for good conclusions to be drawn about the viability of the two types of hardware used, both individually and together. On the subject of the transputer as the workhorse, there were several areas whlch required investigation. Initial work had to cover the choice of network topology on whlch the benchmarking of some of the image processing applications were performed. Research into this was based on the previous work of several authors, whlch introduced features relevant to this investigation. The network used for this investigation was chosen to be generally applicable to a broad spectrum of applications in image processing. It was not chosen for its applicability for a single dedicated application, as has been the case for much of the past research performed in image processing [SAN88] [SCH89]. The concept of image processing techniques being implemented on the transputer required careful consideration in respect of what should be implemented. Image processing is not a new subject, and it encompasses a large spectrum of applications. The transputer, with image processing being hlghly suited to it, has attracted a good deal of research. It would not be rash to say that the easy research was covered first. The more trivial operations in image processing, requiring matrix type operations on the pixels attracted, the most coverage. Several researchers in the field of image processing on the transputer have broken the back of this set of problems. Conclusions regarding these operations on the transputer returned a fairly standard answer. An area of image processing which has not produced the same volume of return as that concerning the more trivial operations, is the subject of Fourier Analysis, that is, the Fourier Transform. Thus a major part of this project concerns an investigation into the Fourier Transform in image processing, in particular the Fast Fourier Transform. The network chosen for thls research has placed some constraint upon the degree of parallelism that can be achleved. It should be emphasized that this project is not concerned with the most efficient implementation of a specific image processing algorithm on a dedicated topology. Rather, it looks at the feasibility of a general system in the domain of image processing, concerned with a hlghly computationally intensive operation. This has had the effect of testing the processing power of the hardware used, and contributing a widely applicable parallel algorithm for use in Fourier Analysis. 3 These are discussed more fully in Chapter 2, which covers the work related to tbis project. The results of the investigation are presented along with a discussion of the methods throughout the thesis. The final chapter summarizes the findings of the research, assesses the value of the investigation, and points out areas for future investigation.
- Full Text:
- Date Issued: 1990
- Authors: Cooke, Nicholas Duncan
- Date: 1990 , 2013-02-07
- Subjects: Image processing , Computer graphics , Fourier transformations -- Data processing , Transputers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4679 , http://hdl.handle.net/10962/d1006702 , Image processing , Computer graphics , Fourier transformations -- Data processing , Transputers
- Description: From Introduction: The research concentrates primarily on a feasibility study involving the setting up of an image processing workstation. As broad as this statement concerning the workstation may seem, there are several factors limiting the extent of the research. This project is not concerned with the design and implementation of a fully-fledged image processing workstation. Rather, it concerns an initial feasibility study of such a workstation, centered on the theme image processing aided by the parallel processing paradigm. In looking at the hardware available for the project, in the context of an image processing environment, a large amount of initial investigation was required prior to that concerned with the transputer and parallel processing. Work was done on the capturing and displaying of images. This formed a vital part of the project. Furthermore, considering that a new architecture was being used as the work horse within a conventional host architecture, the INTEL 80286, several aspects of the host architecture had also to be investigated. These included the actual processing capabilities of the host, the capturing and storing of the images on the host, and most importantly, the interface between the host and the transputer [C0089]. Benchmarking was important in order for good conclusions to be drawn about the viability of the two types of hardware used, both individually and together. On the subject of the transputer as the workhorse, there were several areas whlch required investigation. Initial work had to cover the choice of network topology on whlch the benchmarking of some of the image processing applications were performed. Research into this was based on the previous work of several authors, whlch introduced features relevant to this investigation. The network used for this investigation was chosen to be generally applicable to a broad spectrum of applications in image processing. It was not chosen for its applicability for a single dedicated application, as has been the case for much of the past research performed in image processing [SAN88] [SCH89]. The concept of image processing techniques being implemented on the transputer required careful consideration in respect of what should be implemented. Image processing is not a new subject, and it encompasses a large spectrum of applications. The transputer, with image processing being hlghly suited to it, has attracted a good deal of research. It would not be rash to say that the easy research was covered first. The more trivial operations in image processing, requiring matrix type operations on the pixels attracted, the most coverage. Several researchers in the field of image processing on the transputer have broken the back of this set of problems. Conclusions regarding these operations on the transputer returned a fairly standard answer. An area of image processing which has not produced the same volume of return as that concerning the more trivial operations, is the subject of Fourier Analysis, that is, the Fourier Transform. Thus a major part of this project concerns an investigation into the Fourier Transform in image processing, in particular the Fast Fourier Transform. The network chosen for thls research has placed some constraint upon the degree of parallelism that can be achleved. It should be emphasized that this project is not concerned with the most efficient implementation of a specific image processing algorithm on a dedicated topology. Rather, it looks at the feasibility of a general system in the domain of image processing, concerned with a hlghly computationally intensive operation. This has had the effect of testing the processing power of the hardware used, and contributing a widely applicable parallel algorithm for use in Fourier Analysis. 3 These are discussed more fully in Chapter 2, which covers the work related to tbis project. The results of the investigation are presented along with a discussion of the methods throughout the thesis. The final chapter summarizes the findings of the research, assesses the value of the investigation, and points out areas for future investigation.
- Full Text:
- Date Issued: 1990
Interactions between fig wasps and their host figs
- Authors: Nefdt, Rory John Charlton
- Date: 1990
- Subjects: Wasps , Mutualism (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5718 , http://hdl.handle.net/10962/d1005404 , Wasps , Mutualism (Biology)
- Description: Fig trees (Ficus spp.) and fig wasps (Hymenoptera: Agaonidae) are partners in an intimate mutualism. The trees provide ovules in which wasp larvae develop while the wasps pollinate the flowers and are therefore indispensible for fig seed production. Agaonid fig wasps oviposit down the styles of fig flowers and it has generally been accepted that they were unable to reach the ovules of "long" styled flowers , which would produce seeds, thus maintaining an evolutionary stable mutualism. African fig species were found to have unimodal style length frequencies, with no separation into long and short styled flowers. In several species the ovipositors of their associated agaonids were long enough to reach the majority of ovules. The number of foundress agaonids entering a fig influenced fig seed set and therefore was an important factor regulating the proportion of flowers producing seeds or pollinators. In the two Ficus species that were studied, entry of more than three agaonid foundresses into one fig resulted in competition for limited oviposition sites and less female - biased offspring sex ratios. It is hypothesised that sequential laying of male eggs followed by female eggs, under variable oviposition site limitation, results in sex ratio adjustment, as predicted by local mate competition theory. Evidence in support of this hypothesis is presented. A number of non - pollinating torymid and pteromalid fig wasps also oviposit into each fig species. The sycophagines and sycoecines oviposit down the styles from inside the fig inflorescences like their agaonid counterparts, while other species insert their ovipositors through the wall of the fig from the outside. Like the agaonids, sycophagines were characterised by being pro - ovigenic, with numerous fully developed eggs at emergence. Sycoecines were able to re - emerge from figs they had oviposited in and lay their eggs in more than one fig. They had short ovipositors, allowing access to a smaller proportion of flowers than agaonids or sycophagines. Externally ovipositing fig wasps were syn-ovigenic, able to develop eggs as adults and invested more energy and time during each oviposition event. Differences in the ovipositor lengths of these species did not segregate their oviposition sites spatially, and therefore does not reduce competition between species. Attack by parasitoids and inquiline fig wasps from the exterior did not constitute a selection pressure against agaonids ovipositing in ovules closer to the periphery of the fig's surface, as predicted by Michaloud's enemy-free-space hypothes is. It cannot therefore explain the preference shown by ovipositing agaonids for shorter styled flowers.
- Full Text:
- Date Issued: 1990
- Authors: Nefdt, Rory John Charlton
- Date: 1990
- Subjects: Wasps , Mutualism (Biology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5718 , http://hdl.handle.net/10962/d1005404 , Wasps , Mutualism (Biology)
- Description: Fig trees (Ficus spp.) and fig wasps (Hymenoptera: Agaonidae) are partners in an intimate mutualism. The trees provide ovules in which wasp larvae develop while the wasps pollinate the flowers and are therefore indispensible for fig seed production. Agaonid fig wasps oviposit down the styles of fig flowers and it has generally been accepted that they were unable to reach the ovules of "long" styled flowers , which would produce seeds, thus maintaining an evolutionary stable mutualism. African fig species were found to have unimodal style length frequencies, with no separation into long and short styled flowers. In several species the ovipositors of their associated agaonids were long enough to reach the majority of ovules. The number of foundress agaonids entering a fig influenced fig seed set and therefore was an important factor regulating the proportion of flowers producing seeds or pollinators. In the two Ficus species that were studied, entry of more than three agaonid foundresses into one fig resulted in competition for limited oviposition sites and less female - biased offspring sex ratios. It is hypothesised that sequential laying of male eggs followed by female eggs, under variable oviposition site limitation, results in sex ratio adjustment, as predicted by local mate competition theory. Evidence in support of this hypothesis is presented. A number of non - pollinating torymid and pteromalid fig wasps also oviposit into each fig species. The sycophagines and sycoecines oviposit down the styles from inside the fig inflorescences like their agaonid counterparts, while other species insert their ovipositors through the wall of the fig from the outside. Like the agaonids, sycophagines were characterised by being pro - ovigenic, with numerous fully developed eggs at emergence. Sycoecines were able to re - emerge from figs they had oviposited in and lay their eggs in more than one fig. They had short ovipositors, allowing access to a smaller proportion of flowers than agaonids or sycophagines. Externally ovipositing fig wasps were syn-ovigenic, able to develop eggs as adults and invested more energy and time during each oviposition event. Differences in the ovipositor lengths of these species did not segregate their oviposition sites spatially, and therefore does not reduce competition between species. Attack by parasitoids and inquiline fig wasps from the exterior did not constitute a selection pressure against agaonids ovipositing in ovules closer to the periphery of the fig's surface, as predicted by Michaloud's enemy-free-space hypothes is. It cannot therefore explain the preference shown by ovipositing agaonids for shorter styled flowers.
- Full Text:
- Date Issued: 1990
Persuasuve conflict: an hermeneutical model for interpreting Galatians in the context of the South African church
- Authors: Holgate, David A
- Date: 1990
- Subjects: Bible. Galatians -- Criticism, Textual , Liberation theology -- South Africa
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1213 , http://hdl.handle.net/10962/d1001542
- Description: This study looks at how to interpret Paul's letter to the Galatians in the contemporary South African church. It aims to provide a Bible study method for doing this which accounts both for the context in which interpretation takes place and for the requirements of exegesis. To this end, use is made of a combination of contextual Bible study methods and a recent multidimensional exegetical model, all of which are currently employed in South Africa. Initially, the study surveys a range of recent critical approaches to the Pauline epistles, particularly as these are employed by South African scholars working on Galatians. The fact that different exegetical approaches focus on different dimensions of the text, reveals the usefulness of a multidimensional exegetical model. The multidimensional exegetical model of Rousseau, which functions within a communication paradigm, is then introduced as an exegetical guide. To meet the second requirement of this study, the question of contextual exegesis is examined. Particular use is made of the hermeneutical approach of liberation theology, with its three mediations of social analysis, theological reflection and practical implementation. The central part of this study explores the implications of contextual interpretation and multidimensional exegesis of Galatians. The pre-canonical, canonical and contemporary contexts which affect the understanding of Galatians are discussed, and the multidimensional exegetical model is used to introduce the Galatian letter as a whole. The last part deals with the practical questions of group Bible study. The exegetical and hermeneutical theory developed earlier is simplified to provide a contextual Bible study method and this method is applied to three pericopes from Galatians. The task of bridging the gap between the university and the church is not an easy one, nor one which is solved by a single Bible study method. The exegetical and hermeneutical questions raised here point to the need for ongoing interaction between South African community of biblical scholars and those involved in the everyday life of the South African church
- Full Text:
- Date Issued: 1990
- Authors: Holgate, David A
- Date: 1990
- Subjects: Bible. Galatians -- Criticism, Textual , Liberation theology -- South Africa
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1213 , http://hdl.handle.net/10962/d1001542
- Description: This study looks at how to interpret Paul's letter to the Galatians in the contemporary South African church. It aims to provide a Bible study method for doing this which accounts both for the context in which interpretation takes place and for the requirements of exegesis. To this end, use is made of a combination of contextual Bible study methods and a recent multidimensional exegetical model, all of which are currently employed in South Africa. Initially, the study surveys a range of recent critical approaches to the Pauline epistles, particularly as these are employed by South African scholars working on Galatians. The fact that different exegetical approaches focus on different dimensions of the text, reveals the usefulness of a multidimensional exegetical model. The multidimensional exegetical model of Rousseau, which functions within a communication paradigm, is then introduced as an exegetical guide. To meet the second requirement of this study, the question of contextual exegesis is examined. Particular use is made of the hermeneutical approach of liberation theology, with its three mediations of social analysis, theological reflection and practical implementation. The central part of this study explores the implications of contextual interpretation and multidimensional exegesis of Galatians. The pre-canonical, canonical and contemporary contexts which affect the understanding of Galatians are discussed, and the multidimensional exegetical model is used to introduce the Galatian letter as a whole. The last part deals with the practical questions of group Bible study. The exegetical and hermeneutical theory developed earlier is simplified to provide a contextual Bible study method and this method is applied to three pericopes from Galatians. The task of bridging the gap between the university and the church is not an easy one, nor one which is solved by a single Bible study method. The exegetical and hermeneutical questions raised here point to the need for ongoing interaction between South African community of biblical scholars and those involved in the everyday life of the South African church
- Full Text:
- Date Issued: 1990
Religious experience and schizophrenia in modern man : an experiential theoretical study
- Borchardt, Frederick Francois
- Authors: Borchardt, Frederick Francois
- Date: 1990
- Subjects: Schizophrenia -- Religious aspects , Experience (Religion) -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2897 , http://hdl.handle.net/10962/d1002061
- Description: In this study the psychological structures of two categories of religious and schizophrenic experience were examined from a phenomenological- existential perspective. Existing theories describe schizophrenia as an unfree, rigid experience with limited possibilities for selfhood. Some theorists believe, however, that some forms of schizophrenia can be seen as potential growth experiences which could facilitate existential renewal. These forms of schizophrenia are mystical, mythical or spiritual in nature. Religious experiences are, according to the literature, essentially renewal experiences facilitating existential growth and transformation through a particular system of thought and devotional relationship shared by a group of people. The Duquesne phenomenological- psychological method was used to analyse seven case studies, four of which involved schizophrenic experiences and three which involved religious conversion experiences. The general psychological structure which emerged through this analysis showed both schizophrenia and religious experience to have specific implications for the personal, social, material and mystical dimensions of being. The description of a specific psychological structure of experience which could optimally facilitate existential growth and transformation was attained by examining psychological structures where the subject's experience culminated in existential growth and transformation (such as religious experience and certain schizophrenIc experiences). As both these categories of experience displayed a strong mystical component, a psychological structure of experience which facilitates a transformative mystical experience was described. It can be concluded that an experience involving a mystical dimension could be transformative if the general psychological structure of the person displays (a) an openness towards reality as it presents itself (b) an experience of oneself as having a measure of existential freedom (c) a certain sense of security in one's own selfhood and (d) a social world which could understand, support and reflect inner experiences.
- Full Text:
- Date Issued: 1990
- Authors: Borchardt, Frederick Francois
- Date: 1990
- Subjects: Schizophrenia -- Religious aspects , Experience (Religion) -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2897 , http://hdl.handle.net/10962/d1002061
- Description: In this study the psychological structures of two categories of religious and schizophrenic experience were examined from a phenomenological- existential perspective. Existing theories describe schizophrenia as an unfree, rigid experience with limited possibilities for selfhood. Some theorists believe, however, that some forms of schizophrenia can be seen as potential growth experiences which could facilitate existential renewal. These forms of schizophrenia are mystical, mythical or spiritual in nature. Religious experiences are, according to the literature, essentially renewal experiences facilitating existential growth and transformation through a particular system of thought and devotional relationship shared by a group of people. The Duquesne phenomenological- psychological method was used to analyse seven case studies, four of which involved schizophrenic experiences and three which involved religious conversion experiences. The general psychological structure which emerged through this analysis showed both schizophrenia and religious experience to have specific implications for the personal, social, material and mystical dimensions of being. The description of a specific psychological structure of experience which could optimally facilitate existential growth and transformation was attained by examining psychological structures where the subject's experience culminated in existential growth and transformation (such as religious experience and certain schizophrenIc experiences). As both these categories of experience displayed a strong mystical component, a psychological structure of experience which facilitates a transformative mystical experience was described. It can be concluded that an experience involving a mystical dimension could be transformative if the general psychological structure of the person displays (a) an openness towards reality as it presents itself (b) an experience of oneself as having a measure of existential freedom (c) a certain sense of security in one's own selfhood and (d) a social world which could understand, support and reflect inner experiences.
- Full Text:
- Date Issued: 1990
Sand inundation on rocky shores : its effects on species richness and the structure of species assemblages
- Authors: Dower, Katherine Mary
- Date: 1990
- Subjects: Intertidal ecology , Tide pool ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5814 , http://hdl.handle.net/10962/d1007183 , Intertidal ecology , Tide pool ecology
- Description: Although sand deposits are present on many intertidal rocky shores, their effects on species richness, zonation and trophic structure have often been overlooked. This study is the first to recognise sand as an important abiotic factor on South African rocky shores. Rocky shores in the eastern Cape Province of South Africa are subject to extensive sand inundation and are composed of two hard substrata of differing topographies. Four sites on one substratum and six on the other were sampled quantitatively using quadrats. The biota were identified, counted and/ or weighed to provide a matrix of species biomass and numbers in separate zones. This matrix was then analysed using ordination and classification. A total of 321 species were identified which is more than local rocky or sandy shores. While the intermediate disturbance hypothesis would predict high species richness on these shores, it does not fully explain this richness nor the distribution of species assemblages. Habitat heterogeneity, including the dynamics of sand deposits, is strongly influenced by substratum topography and is the most important factor generating species richness. Abrasion by sand (sand scour) causes local reductions in richness but the presence of semi-permanent sand deposits allows habitation by psammophilic and sand-dependent species. As a result the biota of a sand inundated rocky shore includes both a full rocky shore and a large sandy beach component. Substratum topography controls patterns of sand deposition and retention and community analysis showed that samples were clustered primarily according to species richness and secondarily according to substratum type. Ordination of species identified an arc of species assemblages of decreasing levels of sand tolerance. These corresponded to sample groupings so that th assemblages found in various habitats were characterised by particular levels of sand tolerance. The presence of sand has a negative effect on the biomass of primary producers and filter feeders but a positive effect on the biomass of deposit feeders. Because sand is retained to different degrees in different zones, trophic structure varies between zones and to a lesser extent, between rock types. In general, however, the trophic structure of sand inundated rocky shores is similar to that of non-inundated shores.
- Full Text:
- Date Issued: 1990
- Authors: Dower, Katherine Mary
- Date: 1990
- Subjects: Intertidal ecology , Tide pool ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5814 , http://hdl.handle.net/10962/d1007183 , Intertidal ecology , Tide pool ecology
- Description: Although sand deposits are present on many intertidal rocky shores, their effects on species richness, zonation and trophic structure have often been overlooked. This study is the first to recognise sand as an important abiotic factor on South African rocky shores. Rocky shores in the eastern Cape Province of South Africa are subject to extensive sand inundation and are composed of two hard substrata of differing topographies. Four sites on one substratum and six on the other were sampled quantitatively using quadrats. The biota were identified, counted and/ or weighed to provide a matrix of species biomass and numbers in separate zones. This matrix was then analysed using ordination and classification. A total of 321 species were identified which is more than local rocky or sandy shores. While the intermediate disturbance hypothesis would predict high species richness on these shores, it does not fully explain this richness nor the distribution of species assemblages. Habitat heterogeneity, including the dynamics of sand deposits, is strongly influenced by substratum topography and is the most important factor generating species richness. Abrasion by sand (sand scour) causes local reductions in richness but the presence of semi-permanent sand deposits allows habitation by psammophilic and sand-dependent species. As a result the biota of a sand inundated rocky shore includes both a full rocky shore and a large sandy beach component. Substratum topography controls patterns of sand deposition and retention and community analysis showed that samples were clustered primarily according to species richness and secondarily according to substratum type. Ordination of species identified an arc of species assemblages of decreasing levels of sand tolerance. These corresponded to sample groupings so that th assemblages found in various habitats were characterised by particular levels of sand tolerance. The presence of sand has a negative effect on the biomass of primary producers and filter feeders but a positive effect on the biomass of deposit feeders. Because sand is retained to different degrees in different zones, trophic structure varies between zones and to a lesser extent, between rock types. In general, however, the trophic structure of sand inundated rocky shores is similar to that of non-inundated shores.
- Full Text:
- Date Issued: 1990
Synthetic and spectrometric investigation of 1,4-benzoxazepines
- Authors: Whittal, R D
- Date: 1990
- Subjects: Spectrum analysis , Benzodiazepines
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4381 , http://hdl.handle.net/10962/d1005046
- Description: Flavanone (2,3-dihydro-2-phenyl-4H-benzopyran-4-one) and a series of 4'- and 7-halogeno derivatives were prepared from the corresponding 2'-hydroxychalcones [1-(2-hydroxyphenyl)-3-phenyl-2-propen-l-ones], which, in turn, were synthesized by aldol condensation of substituted 2'-hydroxacetophenones with various benzaldehydes. A series of 2,3-dihydro-2-phenyl-l,4-benzoxazepin-5(4H)-ones were prepared by ring expansion of the corresponding flavanones, via the Schmidt reaction, using trimethylsilylazide and trifluoroacetic acid. A series of tetrazoles {2,3-dihydro-2-phenyl-tetrazolo[1,5-d]-1,4-benzoxazepines} were also isolated as by-products of the Schmidt reaction. Flavanone oxime was synthesized for use in Beckmann reactions, and its molecular structure was determined by x-ray crystallography. Attempts to prepare 1,4-benzoxazepinone or its 1,5-analogue via Beckmann rearrangement of flavanone oxime, with polyphosphoric acid or phosphorus pentachloride catalysts, however, were unsuccessful. Several methods for introducing Δ²-unsaturation into the benzoxazepinone system were also examined. High resolution ¹H n.m.r., computer modelling, and molecular mechanics techniques were used to determine the conformations of the heterocycles of the benzoxazepinones and tetrazoles and results are compared with earlier studies in this field. Certain trends in the fragmentation patterns were observed in the low resolution mass spectra of the benzoxazepinones and tetrazoles, and high resolution mass spectrometric data were used to explore the major fragmentation patterns of these compounds.
- Full Text:
- Date Issued: 1990
- Authors: Whittal, R D
- Date: 1990
- Subjects: Spectrum analysis , Benzodiazepines
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4381 , http://hdl.handle.net/10962/d1005046
- Description: Flavanone (2,3-dihydro-2-phenyl-4H-benzopyran-4-one) and a series of 4'- and 7-halogeno derivatives were prepared from the corresponding 2'-hydroxychalcones [1-(2-hydroxyphenyl)-3-phenyl-2-propen-l-ones], which, in turn, were synthesized by aldol condensation of substituted 2'-hydroxacetophenones with various benzaldehydes. A series of 2,3-dihydro-2-phenyl-l,4-benzoxazepin-5(4H)-ones were prepared by ring expansion of the corresponding flavanones, via the Schmidt reaction, using trimethylsilylazide and trifluoroacetic acid. A series of tetrazoles {2,3-dihydro-2-phenyl-tetrazolo[1,5-d]-1,4-benzoxazepines} were also isolated as by-products of the Schmidt reaction. Flavanone oxime was synthesized for use in Beckmann reactions, and its molecular structure was determined by x-ray crystallography. Attempts to prepare 1,4-benzoxazepinone or its 1,5-analogue via Beckmann rearrangement of flavanone oxime, with polyphosphoric acid or phosphorus pentachloride catalysts, however, were unsuccessful. Several methods for introducing Δ²-unsaturation into the benzoxazepinone system were also examined. High resolution ¹H n.m.r., computer modelling, and molecular mechanics techniques were used to determine the conformations of the heterocycles of the benzoxazepinones and tetrazoles and results are compared with earlier studies in this field. Certain trends in the fragmentation patterns were observed in the low resolution mass spectra of the benzoxazepinones and tetrazoles, and high resolution mass spectrometric data were used to explore the major fragmentation patterns of these compounds.
- Full Text:
- Date Issued: 1990
The applicability of two simple single event rainfall-runoff models to catchments with different climate and physiography
- Authors: Beater, Anne Brenda
- Date: 1990
- Subjects: Hydrogeology Runoff -- South Africa Runoff -- United States Rain and rainfall -- South Africa Rain and rainfall -- United States
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4796 , http://hdl.handle.net/10962/d1001896
- Description: The study presents the results of applying two isolated event, constant runoff proportion, conceptual models to a range of catchments drawn from various climatic and physiographic regions of South Africa and the USA. The models can be operated in either lumped or semi-distributed modes. The research progressed through the following stages. The initial stage involved the calibration of both models on two sets of catchments so that an initial evaluation of the performance of the models could be carried out and any deficiencies in the model structure identified, and where practical, corrected. The models were then calibrated on a further 8 catchments. An important result of the calibration is that for both models to produce reasonably acceptable simulations, at least one parameter has to vary between storms on the same catchment to account for variations in storm or antecedent moisture characteristics. The next stage consisted of compiling quantitative descriptions of the physical characteristics of the catchments and rainfall events and an attempt to relate the calibrated parameter values to relevant physical characteristics for the purpose of estimating parameter values when calibration is not possible. Despite the difficulties encountered in quantifying some of the hydrological characteristics the general trends exhibited by many of the relationships are encouraging and the format of the combinations of physical variables used, do make sense with respect to the original parameter conceptualisations. The relationships between storm characteristics and parameters of both models are less satisfactory. There is a high degree of scatter and the between-catchment variation in the form of the relationships, indicates that the derived relationships are likely to be of little use for parameter estimation purposes. The final stage involved a validation exercise in which new parameters were estimated from the physical variable-parameter relationships for all the catchments previously used, as well as a further four. The new parameters were used to re-simulate all the storms and comparison of these results were made with the original calibration results. Both models produced poor results and are unlikely to give reliable results where calibration is not possible. The parameter relationships for the parameters related to storm characteristics are so catchment specific that transfer to other areas will produce unpredictable results. Foot note:- For compatability with computer printouts decimal full stops are used in the format of real numbers in tables etc
- Full Text:
- Date Issued: 1990
- Authors: Beater, Anne Brenda
- Date: 1990
- Subjects: Hydrogeology Runoff -- South Africa Runoff -- United States Rain and rainfall -- South Africa Rain and rainfall -- United States
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4796 , http://hdl.handle.net/10962/d1001896
- Description: The study presents the results of applying two isolated event, constant runoff proportion, conceptual models to a range of catchments drawn from various climatic and physiographic regions of South Africa and the USA. The models can be operated in either lumped or semi-distributed modes. The research progressed through the following stages. The initial stage involved the calibration of both models on two sets of catchments so that an initial evaluation of the performance of the models could be carried out and any deficiencies in the model structure identified, and where practical, corrected. The models were then calibrated on a further 8 catchments. An important result of the calibration is that for both models to produce reasonably acceptable simulations, at least one parameter has to vary between storms on the same catchment to account for variations in storm or antecedent moisture characteristics. The next stage consisted of compiling quantitative descriptions of the physical characteristics of the catchments and rainfall events and an attempt to relate the calibrated parameter values to relevant physical characteristics for the purpose of estimating parameter values when calibration is not possible. Despite the difficulties encountered in quantifying some of the hydrological characteristics the general trends exhibited by many of the relationships are encouraging and the format of the combinations of physical variables used, do make sense with respect to the original parameter conceptualisations. The relationships between storm characteristics and parameters of both models are less satisfactory. There is a high degree of scatter and the between-catchment variation in the form of the relationships, indicates that the derived relationships are likely to be of little use for parameter estimation purposes. The final stage involved a validation exercise in which new parameters were estimated from the physical variable-parameter relationships for all the catchments previously used, as well as a further four. The new parameters were used to re-simulate all the storms and comparison of these results were made with the original calibration results. Both models produced poor results and are unlikely to give reliable results where calibration is not possible. The parameter relationships for the parameters related to storm characteristics are so catchment specific that transfer to other areas will produce unpredictable results. Foot note:- For compatability with computer printouts decimal full stops are used in the format of real numbers in tables etc
- Full Text:
- Date Issued: 1990
The development of professional short term reinsurance in South Africa : 1950-1985
- Authors: Laing, Angus Wallace
- Date: 1990
- Subjects: Reinsurance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:926 , http://hdl.handle.net/10962/d1001452
- Description: This thesis covers the history of short term reinsurance in South Africa from 1950 to 1985 and shows how it developed from a very limited market in which insurers generally relied on British and European professional reinsurers to a viable local market albeit with strong foreign support. The study demonstrates that the local reinsurance market grew in parallel with the development of the South African economy and the consequent need for extensive cover arising from the country's industrial expansion. It considers the different problems of the two waves of locally established reinsurers and the different circumstances prevailing in the two distinct eras of South African short term reinsurance. The conclusion reached is that, notwithstanding the varied results of individual reinsurers and the collapse of two local reinsurance companies, the market performed well and succeeded in meeting the needs of the South African short term insurance market
- Full Text:
- Date Issued: 1990
- Authors: Laing, Angus Wallace
- Date: 1990
- Subjects: Reinsurance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:926 , http://hdl.handle.net/10962/d1001452
- Description: This thesis covers the history of short term reinsurance in South Africa from 1950 to 1985 and shows how it developed from a very limited market in which insurers generally relied on British and European professional reinsurers to a viable local market albeit with strong foreign support. The study demonstrates that the local reinsurance market grew in parallel with the development of the South African economy and the consequent need for extensive cover arising from the country's industrial expansion. It considers the different problems of the two waves of locally established reinsurers and the different circumstances prevailing in the two distinct eras of South African short term reinsurance. The conclusion reached is that, notwithstanding the varied results of individual reinsurers and the collapse of two local reinsurance companies, the market performed well and succeeded in meeting the needs of the South African short term insurance market
- Full Text:
- Date Issued: 1990
The effects of a personal growth programme on self esteem, loneliness and other indicators of divorce adjustment in a group of divorced women
- Authors: Harms-Smith, Linda
- Date: 1990
- Subjects: Divorced women -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: vital:687 , http://hdl.handle.net/10962/d1002012
- Description: Divorce is a major personal and social phenomenon, having a profound effect on those involved both directly or indirectly. The social work profession is faced with a large and vulnerable population at risk, and needs to take cognizance of the effects of divorce as well as the process of divorce adjustment in order to make a contribution in this area. Due to the significantly high divorce statistics, families and individuals are increasingly having to reorganise and adjust to the divorced status. This adjustment is a process which, if successfully negotiated, may ultimately lead to positive personal growth. Divorce, although extremely painful, may therefore paradoxically lead to growth and wholeness. It is during the stage of divorce adjustment that the social worker has a particular role to fulfil. Divorce adjustment may be assessed in terms of the attainment of positive functioning, making use of specific indicators for divorce adjustment. These indicators include self esteem; autonomy vs attachment; loneliness; parenting; social skills; and resolution of feelings around the divorce. Not only is there a need for the development of a clear measure for these indicators and therefore for divorce adjustment, but also for the development of a treatment approach specifically suited to the needs of divorcees in the process of post-divorce adjustment. The present researcher has aimed to address these issues by designing, implementing and then evaluating a personal growth programme and its effects on indicators of divorce adjustment. An extensive review of the literature was done. This covered the impact of divorce, the process of divorce adjustment, indicators of divorce adjustment, social work treatment approaches, and group work in divorce. An empirical study was then conducted whereby an experimental group was exposed to the group work treatment programme and a control group was not. A quasi-experimental design was used to measure the significance of changes in scores on various indicators of divorce adjustment. standardised measuring scales were used for the measurement of self esteem and loneliness, while a measure for indicators of divorce adjustment was especially designed for the purposes of this study. Both the experimental and control groups completed the measurements before and after the period of treatment. The present researcher designed a group work programme related to the needs of divorcees generally, and the needs identified by the participants in the study specifically. It was conducted over a period of ten weeks, consisting of ten one-and-a-half hour sessions. Eight divorced women attended the group. All had children and all had custody of their children. The programme included sessions on self esteem and self awareness; social skills (assertiveness and conflict resolution); loneliness; depression; and parenting. The sessions were structured and learning was based on experiential learning principles with brief didactic inputs. An eclectic approach was used by the researcher, drawing on theoretical models such as cognitive restructuring, gestalt techniques, psycho-drama, the client-centred approach and behaviourist techniques. An atmosphere of mutual support and feedback was encouraged and conscious use was made of self esteem/self-awareness building techniques. The main findings of the study showed that the personal growth programme (using a structured, skills training, self esteem/self awareness building, and experiential learning approach) had a significantly positive effect on self esteem and other indicators of divorce adjustment, but not on loneliness. The programme may therefore successfully be implemented in work towards divorce adjustment among divorced clients.
- Full Text:
- Date Issued: 1990
- Authors: Harms-Smith, Linda
- Date: 1990
- Subjects: Divorced women -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: vital:687 , http://hdl.handle.net/10962/d1002012
- Description: Divorce is a major personal and social phenomenon, having a profound effect on those involved both directly or indirectly. The social work profession is faced with a large and vulnerable population at risk, and needs to take cognizance of the effects of divorce as well as the process of divorce adjustment in order to make a contribution in this area. Due to the significantly high divorce statistics, families and individuals are increasingly having to reorganise and adjust to the divorced status. This adjustment is a process which, if successfully negotiated, may ultimately lead to positive personal growth. Divorce, although extremely painful, may therefore paradoxically lead to growth and wholeness. It is during the stage of divorce adjustment that the social worker has a particular role to fulfil. Divorce adjustment may be assessed in terms of the attainment of positive functioning, making use of specific indicators for divorce adjustment. These indicators include self esteem; autonomy vs attachment; loneliness; parenting; social skills; and resolution of feelings around the divorce. Not only is there a need for the development of a clear measure for these indicators and therefore for divorce adjustment, but also for the development of a treatment approach specifically suited to the needs of divorcees in the process of post-divorce adjustment. The present researcher has aimed to address these issues by designing, implementing and then evaluating a personal growth programme and its effects on indicators of divorce adjustment. An extensive review of the literature was done. This covered the impact of divorce, the process of divorce adjustment, indicators of divorce adjustment, social work treatment approaches, and group work in divorce. An empirical study was then conducted whereby an experimental group was exposed to the group work treatment programme and a control group was not. A quasi-experimental design was used to measure the significance of changes in scores on various indicators of divorce adjustment. standardised measuring scales were used for the measurement of self esteem and loneliness, while a measure for indicators of divorce adjustment was especially designed for the purposes of this study. Both the experimental and control groups completed the measurements before and after the period of treatment. The present researcher designed a group work programme related to the needs of divorcees generally, and the needs identified by the participants in the study specifically. It was conducted over a period of ten weeks, consisting of ten one-and-a-half hour sessions. Eight divorced women attended the group. All had children and all had custody of their children. The programme included sessions on self esteem and self awareness; social skills (assertiveness and conflict resolution); loneliness; depression; and parenting. The sessions were structured and learning was based on experiential learning principles with brief didactic inputs. An eclectic approach was used by the researcher, drawing on theoretical models such as cognitive restructuring, gestalt techniques, psycho-drama, the client-centred approach and behaviourist techniques. An atmosphere of mutual support and feedback was encouraged and conscious use was made of self esteem/self-awareness building techniques. The main findings of the study showed that the personal growth programme (using a structured, skills training, self esteem/self awareness building, and experiential learning approach) had a significantly positive effect on self esteem and other indicators of divorce adjustment, but not on loneliness. The programme may therefore successfully be implemented in work towards divorce adjustment among divorced clients.
- Full Text:
- Date Issued: 1990
The evaluation of qualitative examination questions at matriculation level in physics
- Authors: Dixon, Charles Harwood
- Date: 1990
- Subjects: Physics -- Study and teaching (Secondary) , Physics -- Examinations, questions, etc.
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1373 , http://hdl.handle.net/10962/d1001439
- Description: The style and format of Physics examination papers has changed markedly over the past hundred years. Physics was regarded formerly as a sub-division of Mathematics; hence, apart from giving formal statements of scientific laws, and some account of experimental procedures, examination candidates were required to spend most of their time, and to earn most of their marks by solving numerical problems. Most Physics examination papers today retain the emphasis on problem-solving by calculation. It has been recognised, however, that the ability to obtain correct numerical answers by substition in a formula does not necessarily imply understanding of the physical principles which underly the problem. There has been a reaction against the awarding of marks for algebraic or arithmetical manipulation. Bloom and his disciples, by calling on examiners to define precise behavioural objectives, have encouraged the development of qualitative questions. These require no calculation nor numerical answer, but do aim to test the candidate's insight, by requiring him either to explain phenomena in scientific terms, or to predict the outcome of changing conditions. In this investigation samples of both quantitative and qualitative questions were extracted from Physics papers past and present. A closer study was made of qualitative questions used in the Natal Senior Certificate Physics papers (both Higher Grade and Standard Grade) in November 1987. The examiners were asked to state the objective of each question, as well as its categorization in terms of a simplified Bloom taxonomy. Candidates' answers to these questions were extracted from the scripts written at a representative sample of Natal schools. In the case of multiple-choice questions, an item analysis was performed, and discrimination indices were calculated . The responses of individual candidates to the longer questions were collected, classified and discussed. In each case the effectiveness of the question was studied, as to whether or not it was successful in detecting the presence of correct scientific concepts in the candidates' thinking. It was concluded that most of the qualitative questions used by the examiners were effective. Suggestions were made as to how their efficacy could be improved. Much further study and experimentation are needed to develop the effective use of this type of question
- Full Text:
- Date Issued: 1990
- Authors: Dixon, Charles Harwood
- Date: 1990
- Subjects: Physics -- Study and teaching (Secondary) , Physics -- Examinations, questions, etc.
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1373 , http://hdl.handle.net/10962/d1001439
- Description: The style and format of Physics examination papers has changed markedly over the past hundred years. Physics was regarded formerly as a sub-division of Mathematics; hence, apart from giving formal statements of scientific laws, and some account of experimental procedures, examination candidates were required to spend most of their time, and to earn most of their marks by solving numerical problems. Most Physics examination papers today retain the emphasis on problem-solving by calculation. It has been recognised, however, that the ability to obtain correct numerical answers by substition in a formula does not necessarily imply understanding of the physical principles which underly the problem. There has been a reaction against the awarding of marks for algebraic or arithmetical manipulation. Bloom and his disciples, by calling on examiners to define precise behavioural objectives, have encouraged the development of qualitative questions. These require no calculation nor numerical answer, but do aim to test the candidate's insight, by requiring him either to explain phenomena in scientific terms, or to predict the outcome of changing conditions. In this investigation samples of both quantitative and qualitative questions were extracted from Physics papers past and present. A closer study was made of qualitative questions used in the Natal Senior Certificate Physics papers (both Higher Grade and Standard Grade) in November 1987. The examiners were asked to state the objective of each question, as well as its categorization in terms of a simplified Bloom taxonomy. Candidates' answers to these questions were extracted from the scripts written at a representative sample of Natal schools. In the case of multiple-choice questions, an item analysis was performed, and discrimination indices were calculated . The responses of individual candidates to the longer questions were collected, classified and discussed. In each case the effectiveness of the question was studied, as to whether or not it was successful in detecting the presence of correct scientific concepts in the candidates' thinking. It was concluded that most of the qualitative questions used by the examiners were effective. Suggestions were made as to how their efficacy could be improved. Much further study and experimentation are needed to develop the effective use of this type of question
- Full Text:
- Date Issued: 1990
The future of the past in South African schools : curriculum development, school leaving examinations and syllabus design and assessment in history : a comparative study
- Authors: Gunn, Alan Howard
- Date: 1990
- Subjects: Education -- South Africa , Education -- South Africa -- History , Education -- South Africa -- Forecasting
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1375 , http://hdl.handle.net/10962/d1001441
- Description: This is a two-part study dealing with the curriculum, school leaving examinations and History as a school subject in England and South Africa. Part One is a developmental study. Developments in the curriculum of both countries since the Second World War are traced. In England this period is characterised by a shift from a somewhat laissez faire approach of the authorities at Whitehall to the curriculum of individual schools to the prescription that seems inherent in the National Curriculum. The outstanding development in South Africa during this period has been the introduction of a system of differentiated education. In contrast to minor developments in the South African school leaving examination system, England has witnessed the consolidation of the two-tier GCE and CSE system into a single examination at 16+, the GCSE. In discussing developments in History as a school subject, one is struck by the growth of the "new history" in England (this is described in some detail) against the relative lack of development (at "official" syllabus level) in South Africa where the subject remains rooted in the "traditional", chronological, content-based approach. Part Two of this study compares the current situation in England and South Africa at both the macro (ie. curriculum and school leaving examination systems) and micro (ie. History as a subject in the curriculum) levels. At the macro level the curriculum and school leaving examination systems in both England and South Africa are contrasted and one notes an increasing trend towards centralization in both countries. At the micro level use is made of "official" syllabuses and examination papers to contrast the "new history" approach in England with the "traditional" approach in South Africa. In the conclusion two broad possibilities for curriculum reform in South Africa are considered: Broad reform across the curriculum on the one hand and reforms in History on the other
- Full Text:
- Date Issued: 1990
- Authors: Gunn, Alan Howard
- Date: 1990
- Subjects: Education -- South Africa , Education -- South Africa -- History , Education -- South Africa -- Forecasting
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1375 , http://hdl.handle.net/10962/d1001441
- Description: This is a two-part study dealing with the curriculum, school leaving examinations and History as a school subject in England and South Africa. Part One is a developmental study. Developments in the curriculum of both countries since the Second World War are traced. In England this period is characterised by a shift from a somewhat laissez faire approach of the authorities at Whitehall to the curriculum of individual schools to the prescription that seems inherent in the National Curriculum. The outstanding development in South Africa during this period has been the introduction of a system of differentiated education. In contrast to minor developments in the South African school leaving examination system, England has witnessed the consolidation of the two-tier GCE and CSE system into a single examination at 16+, the GCSE. In discussing developments in History as a school subject, one is struck by the growth of the "new history" in England (this is described in some detail) against the relative lack of development (at "official" syllabus level) in South Africa where the subject remains rooted in the "traditional", chronological, content-based approach. Part Two of this study compares the current situation in England and South Africa at both the macro (ie. curriculum and school leaving examination systems) and micro (ie. History as a subject in the curriculum) levels. At the macro level the curriculum and school leaving examination systems in both England and South Africa are contrasted and one notes an increasing trend towards centralization in both countries. At the micro level use is made of "official" syllabuses and examination papers to contrast the "new history" approach in England with the "traditional" approach in South Africa. In the conclusion two broad possibilities for curriculum reform in South Africa are considered: Broad reform across the curriculum on the one hand and reforms in History on the other
- Full Text:
- Date Issued: 1990
The geology and alteration-mineralisation of the Gamigab Tin Prospect, Damaraland, Namibia
- Authors: Walraven, Felix Caspar
- Date: 1990
- Subjects: Mineralogy -- Namibia -- Damaraland , Geology -- Namibia -- Damaraland , Tin mines and mining -- Namibia -- Damaraland
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4956 , http://hdl.handle.net/10962/d1005568 , Mineralogy -- Namibia -- Damaraland , Geology -- Namibia -- Damaraland , Tin mines and mining -- Namibia -- Damaraland
- Description: The stratigraphy at the Gamigab Sn prospect consists of two mainly schistose units separated by a thick marble unit which have been assigned to the Orusewa, the Karibib and the Kuiseb Formations respectively. Four phases of folding affected the lithologies with the south-south-west trending F2 folds defining the main structures in the region. The area underwent low grades of metamorphism. Temperatures were in the range 420° to 500°C and pressures less than 2 kbars. The effects of contact metamorphism are seen in the south-east and south-west. Regional metamorphism outlasted the deformation and contact metamorphism started late during deformation. Two Karoo-age intrusions penetrated the metasediments north of the mineralisation. One is an altered porphyry plug and the other is a weathered dolerite plug, the latter containing xenoliths of undeformed Karoo sediments. Cassiterite is hosted within east-west trending quartz veins that cross-cut previously altered schistose country rocks. The alteration types include sericitisation, tourmalinisation, carbonatisation and ferruginisation. Preliminary Rb/Sr dating on muscovite from the alteration zone suggests an age of 509 ± 11 Ma. Breccias of probable hydrothermal origin are spatially associated with the mineralisation. These hydraulic breccias occur in antiformal structures within the marble and developed in response to a sudden pressure release due to a build up of fluids at the contact between the schistose Orusewa and carbonate Karibib Formations.
- Full Text:
- Date Issued: 1990
- Authors: Walraven, Felix Caspar
- Date: 1990
- Subjects: Mineralogy -- Namibia -- Damaraland , Geology -- Namibia -- Damaraland , Tin mines and mining -- Namibia -- Damaraland
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4956 , http://hdl.handle.net/10962/d1005568 , Mineralogy -- Namibia -- Damaraland , Geology -- Namibia -- Damaraland , Tin mines and mining -- Namibia -- Damaraland
- Description: The stratigraphy at the Gamigab Sn prospect consists of two mainly schistose units separated by a thick marble unit which have been assigned to the Orusewa, the Karibib and the Kuiseb Formations respectively. Four phases of folding affected the lithologies with the south-south-west trending F2 folds defining the main structures in the region. The area underwent low grades of metamorphism. Temperatures were in the range 420° to 500°C and pressures less than 2 kbars. The effects of contact metamorphism are seen in the south-east and south-west. Regional metamorphism outlasted the deformation and contact metamorphism started late during deformation. Two Karoo-age intrusions penetrated the metasediments north of the mineralisation. One is an altered porphyry plug and the other is a weathered dolerite plug, the latter containing xenoliths of undeformed Karoo sediments. Cassiterite is hosted within east-west trending quartz veins that cross-cut previously altered schistose country rocks. The alteration types include sericitisation, tourmalinisation, carbonatisation and ferruginisation. Preliminary Rb/Sr dating on muscovite from the alteration zone suggests an age of 509 ± 11 Ma. Breccias of probable hydrothermal origin are spatially associated with the mineralisation. These hydraulic breccias occur in antiformal structures within the marble and developed in response to a sudden pressure release due to a build up of fluids at the contact between the schistose Orusewa and carbonate Karibib Formations.
- Full Text:
- Date Issued: 1990
The idea of gaiety in Yeats's lyric poetry
- Authors: Brady, Bronwyn
- Date: 1990
- Subjects: Yeats, W. B. (William Butler), 1865-1939 -- Criticism and interpretation , Lyric poetry -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2324 , http://hdl.handle.net/10962/d1015642
- Description: In June 1917 W.B. Yeats wrote to his father : Much of your thought resembles mine . . but mine is part of a religious system more or less logically worked out, a system which will I hope interest you as a form of poetry. I find the setting it all in order has helped my verse, has given me a new framework and new patterns. (Wade 1954, 627) The new framework and new patterns that he claimed to have found in his system generated a new, and for Yeats, radically different sort of poetry. Before 1919 (The Wild Swans at Coole), the poetry had as its subject various traditional themes: the pity of love; the romance and heroism of Irish mythology; the threat of age, change and death. The poetry up to this point is, formally speaking, highly skillful, but locked into its own admissions of failure to touch or incorporate reality in any but a romantically defeatist way. However, the order which Yeats refers to in his letter, and the system he generated as a propaedeutic to this new order, once assimilated into the habit and texture of the poetry, generated new topics of its own which made those of the earlier work seem subjective, self- indulgent and intellectually uninformed. Yeats's poetry now changed drastically in focus and form, from subjective to objective poetry. Whereas the earlier poetry had opposed reality with romantic heroism or selfdestructive despondency, the poetry subsequent to his change of practice, incorporates a new vision of reality as the intrinsic architechtonics of poetry itself. Now the measure of human and aesthetic completion is no longer an inexplicable and inscrutable sadness, but an intelligent and informed detachment, an energy of mind that Yeats called "gaiety". My thesis explores this energy of mind and what it meant for Yeats and his poetry. My contention is that the idea of gaiety provides a way for Yeats to grant meaning to his life, a way for him to create himself. As the poetry is completed thanks to the new system, so is the poet. In order to see this, it is necessary to read the poems as a series of collections, or stories, that resonate back and forth with meaning and qualification and understanding. Yeats's system is his myth, and he writes his poetry in terms of and informed by that myth, shaping and re-shaping the experience of the created and fictional self until it has meaning in a way that the real self does not. The thesis explores this process of creation firstly in theoretical terms, using Lotman's ideas of Story and Myth, and looking at Yeats's intellectual and poetic inheritance. It goes on to examine some of the great poems in an attempt to define gaiety, and how Yeats achieves it in the poetry, and then to look at the early, pre-system poems to see how they differ. Finally, it takes the last of Yeats's lyric collections, Last Poems, and shows how gaiety works in the most mature poetry when the poems are read as narrative events within a story.
- Full Text:
- Date Issued: 1990
- Authors: Brady, Bronwyn
- Date: 1990
- Subjects: Yeats, W. B. (William Butler), 1865-1939 -- Criticism and interpretation , Lyric poetry -- History and criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2324 , http://hdl.handle.net/10962/d1015642
- Description: In June 1917 W.B. Yeats wrote to his father : Much of your thought resembles mine . . but mine is part of a religious system more or less logically worked out, a system which will I hope interest you as a form of poetry. I find the setting it all in order has helped my verse, has given me a new framework and new patterns. (Wade 1954, 627) The new framework and new patterns that he claimed to have found in his system generated a new, and for Yeats, radically different sort of poetry. Before 1919 (The Wild Swans at Coole), the poetry had as its subject various traditional themes: the pity of love; the romance and heroism of Irish mythology; the threat of age, change and death. The poetry up to this point is, formally speaking, highly skillful, but locked into its own admissions of failure to touch or incorporate reality in any but a romantically defeatist way. However, the order which Yeats refers to in his letter, and the system he generated as a propaedeutic to this new order, once assimilated into the habit and texture of the poetry, generated new topics of its own which made those of the earlier work seem subjective, self- indulgent and intellectually uninformed. Yeats's poetry now changed drastically in focus and form, from subjective to objective poetry. Whereas the earlier poetry had opposed reality with romantic heroism or selfdestructive despondency, the poetry subsequent to his change of practice, incorporates a new vision of reality as the intrinsic architechtonics of poetry itself. Now the measure of human and aesthetic completion is no longer an inexplicable and inscrutable sadness, but an intelligent and informed detachment, an energy of mind that Yeats called "gaiety". My thesis explores this energy of mind and what it meant for Yeats and his poetry. My contention is that the idea of gaiety provides a way for Yeats to grant meaning to his life, a way for him to create himself. As the poetry is completed thanks to the new system, so is the poet. In order to see this, it is necessary to read the poems as a series of collections, or stories, that resonate back and forth with meaning and qualification and understanding. Yeats's system is his myth, and he writes his poetry in terms of and informed by that myth, shaping and re-shaping the experience of the created and fictional self until it has meaning in a way that the real self does not. The thesis explores this process of creation firstly in theoretical terms, using Lotman's ideas of Story and Myth, and looking at Yeats's intellectual and poetic inheritance. It goes on to examine some of the great poems in an attempt to define gaiety, and how Yeats achieves it in the poetry, and then to look at the early, pre-system poems to see how they differ. Finally, it takes the last of Yeats's lyric collections, Last Poems, and shows how gaiety works in the most mature poetry when the poems are read as narrative events within a story.
- Full Text:
- Date Issued: 1990
The role of the marriage counsellor in a Xhosa community: an exploratory-descriptive study
- Authors: Phorie, Constancia Lineo
- Date: 1990
- Subjects: Marriage counselling -- South Africa Xhosa (African people) -- Marriage customs and rites Marriage customs Family
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: vital:686 , http://hdl.handle.net/10962/d1002011
- Description: The focus of this study is on the role the marriage counsellor should play in the Black community. This role is being placed in sharp perspective as a result of social change affecting the Black family. Problem-solving, including marriage counselling has traditionally been done by the extended family. This role of the family as a natural support system has been weakened by factors such as urbanization and Westernisation. This has prompted Black couples experiencing in particular marriage problems to make use of professional marriage counselling services from specialised and other welfare agencies. A major problem in the rendering of professional counselling services is that they are to a great extent based on Western civilization as far as basic philosophy and underlying assumptions are concerned. Thus intervention modalities used for marital problems in the Black community do not address the real needs of the people. The main objective of this study was to investigate how marriage counselling services are perceived in the Black community. It is expected that research findings would assist the helping professions make the necessary adjustments to make marriage counselling approaches more relevant to problems experienced in married life in the Black community. The study revealed that the family in the Black community is still regarded as the main problem-solver although people do go beyond the family for assistance. The nuclear family has also started to emerge in the Black community and bonds to the bigger family systems are beginning to loosen. The research findings indicated clearly that there is a need for professional marriage counselling and that services of this nature should be extended further into the Black community. A problem in this regard however is that the community will have to be educated to use these services
- Full Text:
- Date Issued: 1990
- Authors: Phorie, Constancia Lineo
- Date: 1990
- Subjects: Marriage counselling -- South Africa Xhosa (African people) -- Marriage customs and rites Marriage customs Family
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: vital:686 , http://hdl.handle.net/10962/d1002011
- Description: The focus of this study is on the role the marriage counsellor should play in the Black community. This role is being placed in sharp perspective as a result of social change affecting the Black family. Problem-solving, including marriage counselling has traditionally been done by the extended family. This role of the family as a natural support system has been weakened by factors such as urbanization and Westernisation. This has prompted Black couples experiencing in particular marriage problems to make use of professional marriage counselling services from specialised and other welfare agencies. A major problem in the rendering of professional counselling services is that they are to a great extent based on Western civilization as far as basic philosophy and underlying assumptions are concerned. Thus intervention modalities used for marital problems in the Black community do not address the real needs of the people. The main objective of this study was to investigate how marriage counselling services are perceived in the Black community. It is expected that research findings would assist the helping professions make the necessary adjustments to make marriage counselling approaches more relevant to problems experienced in married life in the Black community. The study revealed that the family in the Black community is still regarded as the main problem-solver although people do go beyond the family for assistance. The nuclear family has also started to emerge in the Black community and bonds to the bigger family systems are beginning to loosen. The research findings indicated clearly that there is a need for professional marriage counselling and that services of this nature should be extended further into the Black community. A problem in this regard however is that the community will have to be educated to use these services
- Full Text:
- Date Issued: 1990
The Southern African Development Coordination Conference (SADCC) : part of a whole or a cover?
- Authors: Lubbe, Ingrid Lisa
- Date: 1990
- Subjects: Southern African Development Coordination Conference
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2753 , http://hdl.handle.net/10962/d1002000
- Description: The object of this analysis of the Southern African Development Coordination Conference (SADCC) was to examine the interaction between the states which comprise the organisation in terms of regional and international factors which either facilitated or constrained the pursuit of the organisation's economic goals. To this end a theoretical orientation which would place the organisation in context of regional and international political and economic interaction was necessary. International regime theory was used to place the organisation in an international context, and at the same time provided a theoretical dimension which could be used to analyse empirical evidence on the SADCC organisation's functioning. The application of regime theory clearly highlighted the fact that SADCC's economic goals are constrained by the degree to which all of the SADCC states are integrated on the economic level with western market economy and furthermore , by the fact that these links are reinforced for seven of the nine SADCC states by their economic dependence on South Africa. The above conclusion showed that in terms of the perpetuation of the SADCC organisation as an economic regime, according to the regime theory outlined in Chapter One, the goals of SADCC did not create a firm basis for economic cooperation in the long term. The future of the SADCC organisation in it's present form will depend on how long the racial policies of South Africa continue, for the analysis makes clear that the organisation has much more political than economic coherency. The use of a regime framework showed that in terms of the SADCC states individual economic positions, the historical and structural links between South Africa, the majority of the SADCC states and the West will continue indefinitely due to the strength of the structural economic links between the Southern African region and the western market economy. Thus the analysis proves, within the parameters of international regime theory, the lack of economic coherency within the SADCC organisation's goals, and the strength of the economic ties between the Southern African region and the West.
- Full Text:
- Date Issued: 1990
- Authors: Lubbe, Ingrid Lisa
- Date: 1990
- Subjects: Southern African Development Coordination Conference
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2753 , http://hdl.handle.net/10962/d1002000
- Description: The object of this analysis of the Southern African Development Coordination Conference (SADCC) was to examine the interaction between the states which comprise the organisation in terms of regional and international factors which either facilitated or constrained the pursuit of the organisation's economic goals. To this end a theoretical orientation which would place the organisation in context of regional and international political and economic interaction was necessary. International regime theory was used to place the organisation in an international context, and at the same time provided a theoretical dimension which could be used to analyse empirical evidence on the SADCC organisation's functioning. The application of regime theory clearly highlighted the fact that SADCC's economic goals are constrained by the degree to which all of the SADCC states are integrated on the economic level with western market economy and furthermore , by the fact that these links are reinforced for seven of the nine SADCC states by their economic dependence on South Africa. The above conclusion showed that in terms of the perpetuation of the SADCC organisation as an economic regime, according to the regime theory outlined in Chapter One, the goals of SADCC did not create a firm basis for economic cooperation in the long term. The future of the SADCC organisation in it's present form will depend on how long the racial policies of South Africa continue, for the analysis makes clear that the organisation has much more political than economic coherency. The use of a regime framework showed that in terms of the SADCC states individual economic positions, the historical and structural links between South Africa, the majority of the SADCC states and the West will continue indefinitely due to the strength of the structural economic links between the Southern African region and the western market economy. Thus the analysis proves, within the parameters of international regime theory, the lack of economic coherency within the SADCC organisation's goals, and the strength of the economic ties between the Southern African region and the West.
- Full Text:
- Date Issued: 1990
The spiral curriculum, integrated teaching and structured learning of mathematics at the secondary level
- Authors: Alummoottil, Joseph Michael
- Date: 1990
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa Learning -- Mathematical models -- Research
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1769 , http://hdl.handle.net/10962/d1003654
- Description: The investigator's experience of teaching mathematics at a college of education since 1983 has reinforced his conviction that trainee students come to college with significant gaps, weaknesses and faults in their (mathematical) conceptual structures, probably as a result of shortcomings in the mathematics teaching to which they have been exposed. The theme of this investigation is thus a natural choice that appeared to be of immediate relevance to secondary school mathematics teaching. The analysis of the issue leads to a unified perspective: the problem is placed in a theoretical framework where Bruner [spiral curriculum], Ausubel [structured learning] and Skemp [relational understanding] are brought together. How the curriculum, textbooks and examination influence school mathematics teaching is examined in some depth and the consequences investigated. Two specific topics, viz. the generalised Pythagorean relation and absolute value are investigated in relation to published work, curriculum and textbooks, and each (topic) is presented as a unifying theme in secondary mathematics to standard 9 pupils. The classroom exercise is assessed to test the hypothesis that structured, integrated presentation around a spiral curriculum promotes "relational understanding". Analysis of results supports the hypothesis.
- Full Text:
- Date Issued: 1990
- Authors: Alummoottil, Joseph Michael
- Date: 1990
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa Learning -- Mathematical models -- Research
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1769 , http://hdl.handle.net/10962/d1003654
- Description: The investigator's experience of teaching mathematics at a college of education since 1983 has reinforced his conviction that trainee students come to college with significant gaps, weaknesses and faults in their (mathematical) conceptual structures, probably as a result of shortcomings in the mathematics teaching to which they have been exposed. The theme of this investigation is thus a natural choice that appeared to be of immediate relevance to secondary school mathematics teaching. The analysis of the issue leads to a unified perspective: the problem is placed in a theoretical framework where Bruner [spiral curriculum], Ausubel [structured learning] and Skemp [relational understanding] are brought together. How the curriculum, textbooks and examination influence school mathematics teaching is examined in some depth and the consequences investigated. Two specific topics, viz. the generalised Pythagorean relation and absolute value are investigated in relation to published work, curriculum and textbooks, and each (topic) is presented as a unifying theme in secondary mathematics to standard 9 pupils. The classroom exercise is assessed to test the hypothesis that structured, integrated presentation around a spiral curriculum promotes "relational understanding". Analysis of results supports the hypothesis.
- Full Text:
- Date Issued: 1990
The stock identification of the Cape horse mackerel, Trachurus trachurus capensis (Pisces: Carangidae)
- Authors: Naish, Kerry-Ann
- Date: 1990
- Subjects: Carangidae -- Identification , Trachurus trachurus -- Identification , Carangidae -- South Africa , Trachurus trachurus -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5320 , http://hdl.handle.net/10962/d1005165 , Carangidae -- Identification , Trachurus trachurus -- Identification , Carangidae -- South Africa , Trachurus trachurus -- South Africa
- Description: Three stocks of the Cape horse mackerel, Trachurus trachurus capensis, have been recognised in the ICSEAF convention region off southern Africa (Figure 1) on the basis of catch distribution and biological analyses. They were identified as being off Namibia (ICSEAF Divisions 1 . 3 and 1.4), off the West Coast of South Africa (Div. 1.6) and off the South Coast (Div. 2.1 and 2.2). Recently, speculation as to the accuracy of the classification of the South African populations has arisen. The aim of this study was to determine the number of stocks In Divisions 1.6, 2.1 and 2.2, using methodology which assessed the spatial and temporal nature and the phenotypic and genotypic characteristics of the species. The distribution of horse mackerel was evaluated by studying the trends in catch data and length frequency distributions obtained from the demersal industry during 1986 to 1988 and from the demersal biomass cruises in 1987 and 1988. Adult fish, found in Div. 2.1 and 2.2, probably migrated; during the months in which horse mackerel were expected to spawn, CPUE values were higher over the central Agulhas Bank than in the east of the study region. During the quiescent period, catches and numbers were higher in the latter region. Juvenile horse mackerel were found in the nursery areas utilised by pelagic fish and it is likely that they were transported northward from the Agulhas Bank. A decrease in biomass of individuals in Div. 1.5 indicated a separation between a northern and a southern population. Analyses of the phenotype, or epigenetic characters, of horse mackerel were used as a further test of stock integrity. Monthly samples were drawn from Div. 1.6, 2.1 and 2.2 during May 1988 to June, 1989. Comparisons for the values obtained from growth, length-at-50%-maturity and the season of otolith ring formation from each region showed no significant variation in the phenotype. Morphometric analysis proved inconclusive. Monthly gonadosomatic indices show that fish south of the Orange River share the same spawning season. Reports from the literature show that horse mackerel in the latter region differ from those of northern Namibia in spawning season, age-at-50%-maturity and season of otolith ring formation. The genetic structure of the populations of horse mackerel was evaluated by means of a restriction enzyme analysis of the Mitochondrial DNA of 37 fish collected from Divisions 1.4, 1.5, 1.6, 2.1 and 2.2. Two composite genotypes of horse mackerel were found; one belonging to fish in Div. 1.4 and one to fish in Div. 1.6, 2.1 and 2.2. The genetic distance between the two genotypes, 0.07, was the expected distance between two populations at a subspecies level. Fish in Div. 1.5 consisted of both genotypes and may be a region of mixing between the two populations. The interpretation of results was cautioned; prevlous work has shown that the migration of a small number of individuals between two stocks can be expected to maintain a low variation between the populations. In concluding, it was recommended that the horse mackerel be managed as two stocks, one in Div. 1.3 and 1.4 and one in Div. 1.6, 2.1 and 2.2
- Full Text:
- Date Issued: 1990
- Authors: Naish, Kerry-Ann
- Date: 1990
- Subjects: Carangidae -- Identification , Trachurus trachurus -- Identification , Carangidae -- South Africa , Trachurus trachurus -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5320 , http://hdl.handle.net/10962/d1005165 , Carangidae -- Identification , Trachurus trachurus -- Identification , Carangidae -- South Africa , Trachurus trachurus -- South Africa
- Description: Three stocks of the Cape horse mackerel, Trachurus trachurus capensis, have been recognised in the ICSEAF convention region off southern Africa (Figure 1) on the basis of catch distribution and biological analyses. They were identified as being off Namibia (ICSEAF Divisions 1 . 3 and 1.4), off the West Coast of South Africa (Div. 1.6) and off the South Coast (Div. 2.1 and 2.2). Recently, speculation as to the accuracy of the classification of the South African populations has arisen. The aim of this study was to determine the number of stocks In Divisions 1.6, 2.1 and 2.2, using methodology which assessed the spatial and temporal nature and the phenotypic and genotypic characteristics of the species. The distribution of horse mackerel was evaluated by studying the trends in catch data and length frequency distributions obtained from the demersal industry during 1986 to 1988 and from the demersal biomass cruises in 1987 and 1988. Adult fish, found in Div. 2.1 and 2.2, probably migrated; during the months in which horse mackerel were expected to spawn, CPUE values were higher over the central Agulhas Bank than in the east of the study region. During the quiescent period, catches and numbers were higher in the latter region. Juvenile horse mackerel were found in the nursery areas utilised by pelagic fish and it is likely that they were transported northward from the Agulhas Bank. A decrease in biomass of individuals in Div. 1.5 indicated a separation between a northern and a southern population. Analyses of the phenotype, or epigenetic characters, of horse mackerel were used as a further test of stock integrity. Monthly samples were drawn from Div. 1.6, 2.1 and 2.2 during May 1988 to June, 1989. Comparisons for the values obtained from growth, length-at-50%-maturity and the season of otolith ring formation from each region showed no significant variation in the phenotype. Morphometric analysis proved inconclusive. Monthly gonadosomatic indices show that fish south of the Orange River share the same spawning season. Reports from the literature show that horse mackerel in the latter region differ from those of northern Namibia in spawning season, age-at-50%-maturity and season of otolith ring formation. The genetic structure of the populations of horse mackerel was evaluated by means of a restriction enzyme analysis of the Mitochondrial DNA of 37 fish collected from Divisions 1.4, 1.5, 1.6, 2.1 and 2.2. Two composite genotypes of horse mackerel were found; one belonging to fish in Div. 1.4 and one to fish in Div. 1.6, 2.1 and 2.2. The genetic distance between the two genotypes, 0.07, was the expected distance between two populations at a subspecies level. Fish in Div. 1.5 consisted of both genotypes and may be a region of mixing between the two populations. The interpretation of results was cautioned; prevlous work has shown that the migration of a small number of individuals between two stocks can be expected to maintain a low variation between the populations. In concluding, it was recommended that the horse mackerel be managed as two stocks, one in Div. 1.3 and 1.4 and one in Div. 1.6, 2.1 and 2.2
- Full Text:
- Date Issued: 1990
The taxonomy and life history of the blue stingray, Dasyatis marmorata capensis (Batoidea : Dasyatidae) from Southern Africa
- Cowley, Paul D (Paul Denfer), 1964-
- Authors: Cowley, Paul D (Paul Denfer), 1964-
- Date: 1990
- Subjects: Stingrays -- Africa, Southern Dasyatidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5183 , http://hdl.handle.net/10962/d1001959
- Description: The blue stingray, Dasyatis marmorata capensis is an important recreational shore angling species, especially amongst tournament anglers, in South Africa. The taxonomy and aspects of the biology of this species were investigated from specimens collected between March 1987 and May 1989, from various localities along the southern African coastline. Morphological comparisons were made between Dasyatis pastinaca, Dasyatis marmorata and the local variety. The results indicated that the local variety is different to D. pastinaca in colouration, disc length size, and vertebral and radial counts. The proposed new sub-species Dasyatis marmorata capensis is closest to Dasyatis marmorata of the north-eastern Atlantic coast, but differs in snout angle, disc length and snout to vent length. Analysis of catch per unit of effort data revealed that the blue stingray exhibits distinct seasonality. Adult and sub-adult fish undertake an annual onshore/offshore migration and invade the inshore region between spring and summer, while juveniles remain offshore and utilize this zone as a nursery area. Length-at-age and growth rates for both sexes were estimated from bands formed seasonally in the vertebral centra. The derived von Bertalanffy growth parameters indicated that females reach a greater asymptotic size (913.8 mm DW) and have a slower growth rate (K = -0.07) than males (531.8 mm DW, K = -0.17). Growth rates of juvenile captive specimens compared favourably with back calculated values, at approximately 65 mm/year, for the first year of growth. Dasyatis marmorata capensis is an aplacental viviparous elasmobranch with a well defined annual breeding cycle. Young are released , at a size of 170-200 mm DW, from October to December after a gestation period of approximately nine months. An average fecundity of 3.07 was calculated . Examination of gonadal development indicated that sexual maturity is first attained at a size of 408 and 500 mm DW in males and females, respectively, corresponding to ages 4.5 and 7 years. Size-related food habits were determined independently from three depth zones. The major prey items for each size class were directly related to the abundance of the infauna of the different depth zones. Polychaeta, amphipoda and stomatopoda were the major prey items in the offshore zone. In the nearshore zone, the dominant prey species were Balanoglossus capensis and Callianassa spp .. The high incidence of empty stomachs and the presence of prey items which occur in greatest abundance beyond the surf zone indicated that this zone is not utilized for the purposes of feeding.
- Full Text:
- Date Issued: 1990
- Authors: Cowley, Paul D (Paul Denfer), 1964-
- Date: 1990
- Subjects: Stingrays -- Africa, Southern Dasyatidae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5183 , http://hdl.handle.net/10962/d1001959
- Description: The blue stingray, Dasyatis marmorata capensis is an important recreational shore angling species, especially amongst tournament anglers, in South Africa. The taxonomy and aspects of the biology of this species were investigated from specimens collected between March 1987 and May 1989, from various localities along the southern African coastline. Morphological comparisons were made between Dasyatis pastinaca, Dasyatis marmorata and the local variety. The results indicated that the local variety is different to D. pastinaca in colouration, disc length size, and vertebral and radial counts. The proposed new sub-species Dasyatis marmorata capensis is closest to Dasyatis marmorata of the north-eastern Atlantic coast, but differs in snout angle, disc length and snout to vent length. Analysis of catch per unit of effort data revealed that the blue stingray exhibits distinct seasonality. Adult and sub-adult fish undertake an annual onshore/offshore migration and invade the inshore region between spring and summer, while juveniles remain offshore and utilize this zone as a nursery area. Length-at-age and growth rates for both sexes were estimated from bands formed seasonally in the vertebral centra. The derived von Bertalanffy growth parameters indicated that females reach a greater asymptotic size (913.8 mm DW) and have a slower growth rate (K = -0.07) than males (531.8 mm DW, K = -0.17). Growth rates of juvenile captive specimens compared favourably with back calculated values, at approximately 65 mm/year, for the first year of growth. Dasyatis marmorata capensis is an aplacental viviparous elasmobranch with a well defined annual breeding cycle. Young are released , at a size of 170-200 mm DW, from October to December after a gestation period of approximately nine months. An average fecundity of 3.07 was calculated . Examination of gonadal development indicated that sexual maturity is first attained at a size of 408 and 500 mm DW in males and females, respectively, corresponding to ages 4.5 and 7 years. Size-related food habits were determined independently from three depth zones. The major prey items for each size class were directly related to the abundance of the infauna of the different depth zones. Polychaeta, amphipoda and stomatopoda were the major prey items in the offshore zone. In the nearshore zone, the dominant prey species were Balanoglossus capensis and Callianassa spp .. The high incidence of empty stomachs and the presence of prey items which occur in greatest abundance beyond the surf zone indicated that this zone is not utilized for the purposes of feeding.
- Full Text:
- Date Issued: 1990