Algal biotechnology and the beneficiation of saline effluent wastes
- Authors: Rose, P D (Peter Dale)
- Date: 1992
- Subjects: Algae -- Biotechnology , Algae culture , Tanneries -- Waste disposal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4135 , http://hdl.handle.net/10962/d1015967
- Description: Saline deterioration in the South African public water system has been documented and disposal of brine wastes has been identified as part of the problem. The broad aim of this research programme was to undertake an initial technical study to evaluate the feasibility of integrating algal biotechnology into a disposal function for these wastes. A demonstration of utility in the form of products and waste treatment could produce a beneficiation of saline effluents and provide incentives necessary to deal with the disposal issue. The study attempted to demonstrate a synthesis between the two main thrusts in algal biotechnology that have produced large-scale practical applications - stable, predictable algal production in saline media and the cost effective High Rate Oxidation Ponding (HROP) process for incorporating algal production into a waste treatment function. Tannery organic saline effluents and the biotechnology of Dunaliella salina culture producing β- carotene were chosen as paradigms for the study. 1. The alga was shown to grow in certain tannery effluents producing enhanced biomass yields compared to defined inorganic medium cultivation. The potential for amino acid or protein supplementation of defmed culture media was noted. 2. A reduction in organic load simultaneous with the growth of D.salina was recorded in laboratory-scale simulations of the HROP process. Rates similar to the fresh water HROP equivalent were demonstrated. 3. These results suggested the uptake and storage of organic nitrogen by D.salina. The consequent inhibition of β-carotene accumulation by the organism presented a potentially insurmountable obstacle to the feasibility of β-carotene production in this medium. Uptake and release of organic compounds, previously demonstrated in phytoplankton and other micro-algae, was confirmed in this study for D.salina. The evidence acquired indicated the internalization of both glycine and bovine serum albumin. An ultrastructural study demonstrated mechanisms by which this process might occur. 4. The release of substantial quantities of glycerol was shown. A mechanism whereby D. salina may use this to regulate ammonia availability via control of its associated bacterial population was observed. Glycerol release was identified as presenting an application in treating refractory organic wastes, such as secondary sewage sludges, by elevating C:N ratios. This could demonstrate a significant utility for brine waste impoundments. 5. A multistage production process was proposed to deal with the problem of β-carotene inhibition by separation of the growth and metabolite accumulation functions into separate unit operations. It was shown in this study that the stress of nitrogen deficiency combined with high salinity provides for effectiveβ-carotene accumulation under the conditions of low illumination that pertain in dense cultures. Subjected to these conditions effluent-grown cells show delayed but unimpaired {j-carotene accumulation. 6. A role for the plant hormone abscisic acid in mediating the stress response was demonstrated in D.salina. Fluorescence induction studies suggested the presence of a signalling process forming part of a sensitivity control mechanism. Stress induction of β-carotene accumulation could occur through four clearly defined stages. Potential was identified for using this response as a physiological probe for monitoring and regulating the stress induction process. 7. The multistage processing concept requires effective algal cell separation technology. The use of cross-flow ultrafiltration and diafiltration with a polyethersulfone tubular membrane system was demonstrated as an effective process for the recovery and washing of D. salina. Cell concentrates were produced in a viable form. 8. Process designs incorporating the findings of the research programme are presented demonstrating how effluent and organic waste treatment functions may be combined with the production of D.salina and its products. Application of the multi-stage processing concept to β-carotene production in a defined medium process was identified as offering a potential four-fold yield enhancement. This could have a significant impact on a high cost, marginal algal biotechnology process. Aspects of novelty have been claimed in provisional patents applications. A provisional demonstration of the feasibility of D.salina production in tannery effluent indicates that algal biotechnology may provide a utility for, and hence the beneficiation of saline effluent wastes.
- Full Text:
- Date Issued: 1992
- Authors: Rose, P D (Peter Dale)
- Date: 1992
- Subjects: Algae -- Biotechnology , Algae culture , Tanneries -- Waste disposal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4135 , http://hdl.handle.net/10962/d1015967
- Description: Saline deterioration in the South African public water system has been documented and disposal of brine wastes has been identified as part of the problem. The broad aim of this research programme was to undertake an initial technical study to evaluate the feasibility of integrating algal biotechnology into a disposal function for these wastes. A demonstration of utility in the form of products and waste treatment could produce a beneficiation of saline effluents and provide incentives necessary to deal with the disposal issue. The study attempted to demonstrate a synthesis between the two main thrusts in algal biotechnology that have produced large-scale practical applications - stable, predictable algal production in saline media and the cost effective High Rate Oxidation Ponding (HROP) process for incorporating algal production into a waste treatment function. Tannery organic saline effluents and the biotechnology of Dunaliella salina culture producing β- carotene were chosen as paradigms for the study. 1. The alga was shown to grow in certain tannery effluents producing enhanced biomass yields compared to defined inorganic medium cultivation. The potential for amino acid or protein supplementation of defmed culture media was noted. 2. A reduction in organic load simultaneous with the growth of D.salina was recorded in laboratory-scale simulations of the HROP process. Rates similar to the fresh water HROP equivalent were demonstrated. 3. These results suggested the uptake and storage of organic nitrogen by D.salina. The consequent inhibition of β-carotene accumulation by the organism presented a potentially insurmountable obstacle to the feasibility of β-carotene production in this medium. Uptake and release of organic compounds, previously demonstrated in phytoplankton and other micro-algae, was confirmed in this study for D.salina. The evidence acquired indicated the internalization of both glycine and bovine serum albumin. An ultrastructural study demonstrated mechanisms by which this process might occur. 4. The release of substantial quantities of glycerol was shown. A mechanism whereby D. salina may use this to regulate ammonia availability via control of its associated bacterial population was observed. Glycerol release was identified as presenting an application in treating refractory organic wastes, such as secondary sewage sludges, by elevating C:N ratios. This could demonstrate a significant utility for brine waste impoundments. 5. A multistage production process was proposed to deal with the problem of β-carotene inhibition by separation of the growth and metabolite accumulation functions into separate unit operations. It was shown in this study that the stress of nitrogen deficiency combined with high salinity provides for effectiveβ-carotene accumulation under the conditions of low illumination that pertain in dense cultures. Subjected to these conditions effluent-grown cells show delayed but unimpaired {j-carotene accumulation. 6. A role for the plant hormone abscisic acid in mediating the stress response was demonstrated in D.salina. Fluorescence induction studies suggested the presence of a signalling process forming part of a sensitivity control mechanism. Stress induction of β-carotene accumulation could occur through four clearly defined stages. Potential was identified for using this response as a physiological probe for monitoring and regulating the stress induction process. 7. The multistage processing concept requires effective algal cell separation technology. The use of cross-flow ultrafiltration and diafiltration with a polyethersulfone tubular membrane system was demonstrated as an effective process for the recovery and washing of D. salina. Cell concentrates were produced in a viable form. 8. Process designs incorporating the findings of the research programme are presented demonstrating how effluent and organic waste treatment functions may be combined with the production of D.salina and its products. Application of the multi-stage processing concept to β-carotene production in a defined medium process was identified as offering a potential four-fold yield enhancement. This could have a significant impact on a high cost, marginal algal biotechnology process. Aspects of novelty have been claimed in provisional patents applications. A provisional demonstration of the feasibility of D.salina production in tannery effluent indicates that algal biotechnology may provide a utility for, and hence the beneficiation of saline effluent wastes.
- Full Text:
- Date Issued: 1992
In search of home : Hillman's archetypal perspective on the therapeutic process of an adult patient
- Bradley, Margaret Antoinette
- Authors: Bradley, Margaret Antoinette
- Date: 1992
- Subjects: Hillman, James , Archetype (Psychology) , Psychotherapy -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3127 , http://hdl.handle.net/10962/d1006290 , Hillman, James , Archetype (Psychology) , Psychotherapy -- Case studies
- Description: The case study method was used to trace the therapeutic process of a 23 year old woman, over a period of 12 sessions. The focus of the study was her issue with abandonment which emerged as the central theme in therapy. Hillman's archetypal approach was used as a framework in understanding the process and resolution of her feelings of abandonment. According to Hillman, the therapy process activates the archetypal abandoned child. For a successful therapeutic outcome the process of de-literalisation must occur in order for the patient to move from literal acting out to symbolic containment. Core moments in the therapeutic process were used, together with an interpretation from Hillman's approach, to illustrate the various themes around the issue of abandonment. The present case study illustrates how the theory in area was relevant in practice with this particular case.
- Full Text:
- Date Issued: 1992
- Authors: Bradley, Margaret Antoinette
- Date: 1992
- Subjects: Hillman, James , Archetype (Psychology) , Psychotherapy -- Case studies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3127 , http://hdl.handle.net/10962/d1006290 , Hillman, James , Archetype (Psychology) , Psychotherapy -- Case studies
- Description: The case study method was used to trace the therapeutic process of a 23 year old woman, over a period of 12 sessions. The focus of the study was her issue with abandonment which emerged as the central theme in therapy. Hillman's archetypal approach was used as a framework in understanding the process and resolution of her feelings of abandonment. According to Hillman, the therapy process activates the archetypal abandoned child. For a successful therapeutic outcome the process of de-literalisation must occur in order for the patient to move from literal acting out to symbolic containment. Core moments in the therapeutic process were used, together with an interpretation from Hillman's approach, to illustrate the various themes around the issue of abandonment. The present case study illustrates how the theory in area was relevant in practice with this particular case.
- Full Text:
- Date Issued: 1992
Exploratory studies of novel ligand systems
- Authors: Taylor, Steven John
- Date: 1992
- Subjects: Ligands , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4315 , http://hdl.handle.net/10962/d1004973 , Ligands , Coordination compounds
- Description: A range of novel ligand systems have been developed in three distinct phases and preliminary studies have been initiated to evaluate their complexation potential. Phase I incorporated the synthesis of single strand ligand systems, which were mainly based on amino acid residues. Techniques have been developed for the attachment of these ligand systems onto, firstly, a styrene monomer, and then later onto a pseudo-styrene linking group, viz. the p-toluoyl group. The linking reactions were based on the formation of amides or esters by the reaction of an acid chloride system with an amine or alcohol. Phase II involved the synthesis of bis-chain ligand systems and their attachment onto the p-toluoyl linking group. A further linking group was also developed at this stage, viz. the xylyl group. In the preparation of phase II ligand systems, use was made of malonic ester and iminodiacetic acid derivatives. Phase III has involved the synthesis of cyclic ligand systems, with skeletons based upon the structures used in phase I and phase II and two crown ether type systems have been prepared.
- Full Text:
- Date Issued: 1992
- Authors: Taylor, Steven John
- Date: 1992
- Subjects: Ligands , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4315 , http://hdl.handle.net/10962/d1004973 , Ligands , Coordination compounds
- Description: A range of novel ligand systems have been developed in three distinct phases and preliminary studies have been initiated to evaluate their complexation potential. Phase I incorporated the synthesis of single strand ligand systems, which were mainly based on amino acid residues. Techniques have been developed for the attachment of these ligand systems onto, firstly, a styrene monomer, and then later onto a pseudo-styrene linking group, viz. the p-toluoyl group. The linking reactions were based on the formation of amides or esters by the reaction of an acid chloride system with an amine or alcohol. Phase II involved the synthesis of bis-chain ligand systems and their attachment onto the p-toluoyl linking group. A further linking group was also developed at this stage, viz. the xylyl group. In the preparation of phase II ligand systems, use was made of malonic ester and iminodiacetic acid derivatives. Phase III has involved the synthesis of cyclic ligand systems, with skeletons based upon the structures used in phase I and phase II and two crown ether type systems have been prepared.
- Full Text:
- Date Issued: 1992
A study of Oliver Messiaen's song-cycles Poèms pour mi, Chants de terre et de ciel, and Harawi
- Authors: Donkin, Deborah Jean
- Date: 1992
- Subjects: Messiaen, Olivier, 1908-1992 Song cycles--Interpretation (Phrasing, dynamics, etc.)
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2635 , http://hdl.handle.net/10962/d1002300
- Description: This thesis ventures into the relatively neglected world of twentieth century vocal music, via the three song cycles of Oliver Messiaen. The song cycle is a comparatively young genre, generally dated from Beethoven's An die ferne Geliebte or by some, even later to Schubert's Die schone Miillerin. Nevertheless, considerable changes have taken place in the 160 years which separate Messiaen's cycles from those of the 'pioneers' mentioned above. A fuller appreciation of twentieth century cycles is facilitated by observing this evolutionary process and placing the works within an historical and cultural perspective. Such an introduction is provided in part one of this thesis, along with relevant details on the life and interests of Messiaen. The latter information gives insight into the compositions themselves and may satisfy the reader's curiosity on the origin of some of the more unexpected techniques or ideas Messiaen llses. Before embarking on a study of the cycles, it is necessary to look at the highly individual musical language of the composer. Section two undertakes this task in some depth, wherever possible relating the explanations directly to the songs which follow. In order to clarify the text and to simplify the exercise for the reader, numerous musical examples have been used. This contributes to the apparent bulk of this section. The main emphasis of the thesis is the detailed study of the 20 songs contained in Poemes pour Mi, Chants de Terre et de Cief and Harawi. The third section of the thesis deals with this material thoroughly and systematically, dividing it up into musical and extra-musical aspects. The texts are considered in terms of Surrealist, religious, Nature, numerological and, in the case of Harawi, mythological and Peruvian folk symbolism. The relationship of text to music is studied and evelopments highlighted. Musically, the study is further sub-divided into piano part and vocal part. In each case, an extensive exploration of the techniques required of the performer is presented. This makes possible the subsequent categorisation of the songs on the basis of similarities in the musical means. Conclusions reached show a progressive development through the three song cycles in the composer's handling of the text, his treatment of the voice, his use of the piano and his expansion of the voice-piano relationship. This body of solo vocal literature emerges as typical of Oliver Messiaen's compositional style in general and therefore properly representative of the meticulous craftsmanship with which his works are constructed. The detailed analysis of all aspects of the songs contributes original material to scholarship on Messiaen and on song cycles in the twentieth century.
- Full Text:
- Date Issued: 1992
- Authors: Donkin, Deborah Jean
- Date: 1992
- Subjects: Messiaen, Olivier, 1908-1992 Song cycles--Interpretation (Phrasing, dynamics, etc.)
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2635 , http://hdl.handle.net/10962/d1002300
- Description: This thesis ventures into the relatively neglected world of twentieth century vocal music, via the three song cycles of Oliver Messiaen. The song cycle is a comparatively young genre, generally dated from Beethoven's An die ferne Geliebte or by some, even later to Schubert's Die schone Miillerin. Nevertheless, considerable changes have taken place in the 160 years which separate Messiaen's cycles from those of the 'pioneers' mentioned above. A fuller appreciation of twentieth century cycles is facilitated by observing this evolutionary process and placing the works within an historical and cultural perspective. Such an introduction is provided in part one of this thesis, along with relevant details on the life and interests of Messiaen. The latter information gives insight into the compositions themselves and may satisfy the reader's curiosity on the origin of some of the more unexpected techniques or ideas Messiaen llses. Before embarking on a study of the cycles, it is necessary to look at the highly individual musical language of the composer. Section two undertakes this task in some depth, wherever possible relating the explanations directly to the songs which follow. In order to clarify the text and to simplify the exercise for the reader, numerous musical examples have been used. This contributes to the apparent bulk of this section. The main emphasis of the thesis is the detailed study of the 20 songs contained in Poemes pour Mi, Chants de Terre et de Cief and Harawi. The third section of the thesis deals with this material thoroughly and systematically, dividing it up into musical and extra-musical aspects. The texts are considered in terms of Surrealist, religious, Nature, numerological and, in the case of Harawi, mythological and Peruvian folk symbolism. The relationship of text to music is studied and evelopments highlighted. Musically, the study is further sub-divided into piano part and vocal part. In each case, an extensive exploration of the techniques required of the performer is presented. This makes possible the subsequent categorisation of the songs on the basis of similarities in the musical means. Conclusions reached show a progressive development through the three song cycles in the composer's handling of the text, his treatment of the voice, his use of the piano and his expansion of the voice-piano relationship. This body of solo vocal literature emerges as typical of Oliver Messiaen's compositional style in general and therefore properly representative of the meticulous craftsmanship with which his works are constructed. The detailed analysis of all aspects of the songs contributes original material to scholarship on Messiaen and on song cycles in the twentieth century.
- Full Text:
- Date Issued: 1992
The influence of children on decision-makers in their homes : a case study in environmental education
- Authors: Kruger, Jacqueline
- Date: 1992
- Subjects: Environmental education -- South Africa , Parent and child -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1574 , http://hdl.handle.net/10962/d1003456
- Description: This study explores the possible influence of twenty children on their 'parents', with a view to better understanding the potential 'multiplier effect' of children regarding environmental responsibility. The criteria employed to study the potential influence included certain of the environmental activities learnt by the children during an Environmental Education programme. The programme was undertaken by the researcher with a Std 4 class from Ryneveld Primêreskool in Graaff-Reinet. An action research approach was adopted and results were analysed qualitatively. Due to the short duration and exploratory nature of the project, these results should be viewed as tentative. Proposals are made for increasing the impact of Environmental Education programmes in peri-urban township communities, and recommendations are put forward to help facilitate related studies in the future.
- Full Text:
- Date Issued: 1992
- Authors: Kruger, Jacqueline
- Date: 1992
- Subjects: Environmental education -- South Africa , Parent and child -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1574 , http://hdl.handle.net/10962/d1003456
- Description: This study explores the possible influence of twenty children on their 'parents', with a view to better understanding the potential 'multiplier effect' of children regarding environmental responsibility. The criteria employed to study the potential influence included certain of the environmental activities learnt by the children during an Environmental Education programme. The programme was undertaken by the researcher with a Std 4 class from Ryneveld Primêreskool in Graaff-Reinet. An action research approach was adopted and results were analysed qualitatively. Due to the short duration and exploratory nature of the project, these results should be viewed as tentative. Proposals are made for increasing the impact of Environmental Education programmes in peri-urban township communities, and recommendations are put forward to help facilitate related studies in the future.
- Full Text:
- Date Issued: 1992
A geographical study of agricultural change since the 1930s in Shixini Location, Gatyana district, Transkei
- Authors: Andrew, Maura
- Date: 1992
- Subjects: Agriculture -- South Africa -- Transkei Land tenure -- South Africa -- Transkei Transkei (South Africa) -- Rural conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4834 , http://hdl.handle.net/10962/d1005509
- Description: This study examines the dynamics of agricultural change amongst traditional African smallholder farmers in Shixini location, Gatyana District, Transkei. This entailed an examination of the historical, regional and local causes of agricultural change and the response of the local community. What became evident was that there had been a gradual decline in agricultural output after the 1930s due to a combination of socio-economic and environmental constraints. Pressure on limited resources and land degradation, a consequence of socio-economic pressures on the African peasantry and agricultural expansion, reduced carrying capacities and soil fertility within the African reserves. Racially discriminatory policies also reduced African access to agricultural markets and forced peasants into migrant labour. The initial response to this agricultural decline was to maintain cultivation and pastoral practices, despite declining output, and rely more heavily on migrant labour. However, massive population ~owth from the mid 1950s onwards stimulated a rapid change in cultivation practices. Rural households found it increasingly difficult to gain access to arable land in river valleys and growing poverty undermined their ability to cultivate fields. In response to these conditions the rural population abandoned their fields and expanded garden cultivation. Garden cultivation was a more intensive method of cultivation which made more efficient use of household resources, maintained long-term yields and had a less detrimental impact on the soil. This study attempts to make a contribution to southern African historiography and historical geography. Since the rise of radical human geography in the 1970s there has been a growing number of political economy studies focusing on capitalist expansion, racially discriminatory state policies and associated class conflicts in South Africa. However, most of these studies have focused on urban communities. The political economy of African rural areas has been sorely neglected by human geographers despite the enormous growth of such studies amongst historians and other social scientists. This study of agricultural change in Shixini location, Transkei adds to the small collection of geographical research on the political economy of African rural areas. It also adds to the large body of historical research by focusing on the recent past, a much less well documented period. The most important component of the study was an examination of the response of the rural community to socio-economic and environmental changes. This brought the often neglected role of human agency within the world political economy into the study. Environmental factors, often neglected by'historians and human geographers, were also brought into the analysis. The examination of such a broad range of factors was facilitated through the use of a wide variety of source material including historical, anthropological and socio-economic literature, official statistics, archival records, aerial photographs and a sample survey
- Full Text:
- Date Issued: 1992
- Authors: Andrew, Maura
- Date: 1992
- Subjects: Agriculture -- South Africa -- Transkei Land tenure -- South Africa -- Transkei Transkei (South Africa) -- Rural conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4834 , http://hdl.handle.net/10962/d1005509
- Description: This study examines the dynamics of agricultural change amongst traditional African smallholder farmers in Shixini location, Gatyana District, Transkei. This entailed an examination of the historical, regional and local causes of agricultural change and the response of the local community. What became evident was that there had been a gradual decline in agricultural output after the 1930s due to a combination of socio-economic and environmental constraints. Pressure on limited resources and land degradation, a consequence of socio-economic pressures on the African peasantry and agricultural expansion, reduced carrying capacities and soil fertility within the African reserves. Racially discriminatory policies also reduced African access to agricultural markets and forced peasants into migrant labour. The initial response to this agricultural decline was to maintain cultivation and pastoral practices, despite declining output, and rely more heavily on migrant labour. However, massive population ~owth from the mid 1950s onwards stimulated a rapid change in cultivation practices. Rural households found it increasingly difficult to gain access to arable land in river valleys and growing poverty undermined their ability to cultivate fields. In response to these conditions the rural population abandoned their fields and expanded garden cultivation. Garden cultivation was a more intensive method of cultivation which made more efficient use of household resources, maintained long-term yields and had a less detrimental impact on the soil. This study attempts to make a contribution to southern African historiography and historical geography. Since the rise of radical human geography in the 1970s there has been a growing number of political economy studies focusing on capitalist expansion, racially discriminatory state policies and associated class conflicts in South Africa. However, most of these studies have focused on urban communities. The political economy of African rural areas has been sorely neglected by human geographers despite the enormous growth of such studies amongst historians and other social scientists. This study of agricultural change in Shixini location, Transkei adds to the small collection of geographical research on the political economy of African rural areas. It also adds to the large body of historical research by focusing on the recent past, a much less well documented period. The most important component of the study was an examination of the response of the rural community to socio-economic and environmental changes. This brought the often neglected role of human agency within the world political economy into the study. Environmental factors, often neglected by'historians and human geographers, were also brought into the analysis. The examination of such a broad range of factors was facilitated through the use of a wide variety of source material including historical, anthropological and socio-economic literature, official statistics, archival records, aerial photographs and a sample survey
- Full Text:
- Date Issued: 1992
The development and distribution of heavy mineral concentrations in alluvial systems
- Authors: Lynn, Michael David
- Date: 1992
- Subjects: Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4937 , http://hdl.handle.net/10962/d1005549 , Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Description: The objective of this review is to summarise the characteristics, significance and evolution of heavy minerals and their accumulations, and to identify the key controls on the development and distribution of heavy mineral concentrations in alluvial systems. These controls can be broadly classified as tectonic setting, geomorphic setting and grain-scale concentrating processes, each of which is discussed. Based on this review, exploration models are developed which are designed to indicate favourable localities for the accumulation of heavy minerals, and trends likely to be exhibited within these accumulations. The models are structured from the broadest scale of target selection, down to the local scale of sample site selection. The major conclusion of this work is that an understanding of process geomorphology is required to develop genetic models of placer development, including a detailed evaluation of climatic fluctuations throughout the Caenozoic. Palaeoplacers such as the Witwatersrand goldfield, are inferred to have formed under similar circumstances of tectonic setting as genetically comparable Caenozoic placers such as those of Otago, New Zealand. The means of preservation of such major basins is however poorly understood.
- Full Text:
- Date Issued: 1992
- Authors: Lynn, Michael David
- Date: 1992
- Subjects: Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4937 , http://hdl.handle.net/10962/d1005549 , Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Description: The objective of this review is to summarise the characteristics, significance and evolution of heavy minerals and their accumulations, and to identify the key controls on the development and distribution of heavy mineral concentrations in alluvial systems. These controls can be broadly classified as tectonic setting, geomorphic setting and grain-scale concentrating processes, each of which is discussed. Based on this review, exploration models are developed which are designed to indicate favourable localities for the accumulation of heavy minerals, and trends likely to be exhibited within these accumulations. The models are structured from the broadest scale of target selection, down to the local scale of sample site selection. The major conclusion of this work is that an understanding of process geomorphology is required to develop genetic models of placer development, including a detailed evaluation of climatic fluctuations throughout the Caenozoic. Palaeoplacers such as the Witwatersrand goldfield, are inferred to have formed under similar circumstances of tectonic setting as genetically comparable Caenozoic placers such as those of Otago, New Zealand. The means of preservation of such major basins is however poorly understood.
- Full Text:
- Date Issued: 1992
Paul and Barnabas in Lystra (Acts 14:8-20): the contextualization of the Gospel in a Graeco-Roman city
- Authors: Germiquet, Edouard Ariste
- Date: 1992
- Subjects: Bible. Acts -- Criticism, interpretation, etc.
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1306 , http://hdl.handle.net/10962/d1018213
- Description: This thesis will investigate the extensive Graeco-Roman characteristics of the Lystra speech and in so doing convey some clarity in the otherwise widely differing opinions held about it. This will be achieved by showing that Lystra was a Hellenistic city of some importance with a varied population. It will be argued that the initial reaction of the Lystrians to the miraculous healing of the cripple is to be understood as representing typical Graeco-Roman notions. This will include Luke's use of a legend which not only adds local colouring to the narrative but also introduces Graeco-Roman themes such as the blurring of the distinction between humans and gods and the custom of sacrifice. This contextualization immediately portrays the Graeco-Roman nature of the Lystrians' behaviour and attitudes. In addition to these themes it will be argued that the Lystrians are shown to being reliant on secondary notions of God, which when exposed to the proclamation of the apostles will prove to be inadequate. It will also be argued that the speech of the apostles is structured in a typically Graeco-Roman rhetorical form, where the errors are first exposed before the truth is presented. In conjunction with this structure it will be argued that the philosophical concept of which Dibelius has shown to be clearly presupposed in the Areopagus speech, is not only present in the Lystra speech but forms the philosophical basis on which it is structured. This concept explains the insistence by the apostles that they are human and that God has no need of such worthless things as sacrifices. It also explains the presentation of God's activity in creation and providence as an antithesis to a god who is in need. The Graeco-Roman aspects are brought to a close with the discussion of idea that an awareness of God does not depend on secondary notions acquired from legends or customs but that the truth is grasped through a process of reflection on creation and providence. This is an important notion in the speech for it exposes the Lystrians as being in need of a reorientation of their beliefs in God, away from those which are secondary to those which are primary and compatible with the truth.
- Full Text:
- Date Issued: 1992
- Authors: Germiquet, Edouard Ariste
- Date: 1992
- Subjects: Bible. Acts -- Criticism, interpretation, etc.
- Language: English
- Type: Thesis , Masters , MTh
- Identifier: vital:1306 , http://hdl.handle.net/10962/d1018213
- Description: This thesis will investigate the extensive Graeco-Roman characteristics of the Lystra speech and in so doing convey some clarity in the otherwise widely differing opinions held about it. This will be achieved by showing that Lystra was a Hellenistic city of some importance with a varied population. It will be argued that the initial reaction of the Lystrians to the miraculous healing of the cripple is to be understood as representing typical Graeco-Roman notions. This will include Luke's use of a legend which not only adds local colouring to the narrative but also introduces Graeco-Roman themes such as the blurring of the distinction between humans and gods and the custom of sacrifice. This contextualization immediately portrays the Graeco-Roman nature of the Lystrians' behaviour and attitudes. In addition to these themes it will be argued that the Lystrians are shown to being reliant on secondary notions of God, which when exposed to the proclamation of the apostles will prove to be inadequate. It will also be argued that the speech of the apostles is structured in a typically Graeco-Roman rhetorical form, where the errors are first exposed before the truth is presented. In conjunction with this structure it will be argued that the philosophical concept of which Dibelius has shown to be clearly presupposed in the Areopagus speech, is not only present in the Lystra speech but forms the philosophical basis on which it is structured. This concept explains the insistence by the apostles that they are human and that God has no need of such worthless things as sacrifices. It also explains the presentation of God's activity in creation and providence as an antithesis to a god who is in need. The Graeco-Roman aspects are brought to a close with the discussion of idea that an awareness of God does not depend on secondary notions acquired from legends or customs but that the truth is grasped through a process of reflection on creation and providence. This is an important notion in the speech for it exposes the Lystrians as being in need of a reorientation of their beliefs in God, away from those which are secondary to those which are primary and compatible with the truth.
- Full Text:
- Date Issued: 1992
Namibia's long road to independence : the Botha era
- Authors: Ruiters, Michele René
- Date: 1992
- Subjects: United Nations -- Namibia , Namibia -- History -- 1946-1990 , Namibia -- Politics and government -- 1946-1990
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2754 , http://hdl.handle.net/10962/d1002001
- Description: This thesis deals with the ten years preceding Namibia's independence in March 1990. It examines the various characters and groups in this process, and how their roles delayed or promoted it. The era of Pieter W. Botha is very significant in that his rule brought many changes to the decision-making process and content of South African foreign policy. This period, 1978 - 1989, marked the formulation of the Total National Strategy in response to the Total Onslaught being waged on South Africa by perceived hostile external forces. Namibia's transition to independence suffered under this military-oriented policy as did the rest of the region. Never before in South Africa's policy-making history had the security sector played such a major role. Regional relations changed subsequent to the policy changes because of the distorted vision the Botha regime had of black-ruled states. Namibia was seen as an important pawn in the Total National Strategy as the last buffer state in Southern Africa protecting South Africa's white minority regime
- Full Text:
- Date Issued: 1992
- Authors: Ruiters, Michele René
- Date: 1992
- Subjects: United Nations -- Namibia , Namibia -- History -- 1946-1990 , Namibia -- Politics and government -- 1946-1990
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2754 , http://hdl.handle.net/10962/d1002001
- Description: This thesis deals with the ten years preceding Namibia's independence in March 1990. It examines the various characters and groups in this process, and how their roles delayed or promoted it. The era of Pieter W. Botha is very significant in that his rule brought many changes to the decision-making process and content of South African foreign policy. This period, 1978 - 1989, marked the formulation of the Total National Strategy in response to the Total Onslaught being waged on South Africa by perceived hostile external forces. Namibia's transition to independence suffered under this military-oriented policy as did the rest of the region. Never before in South Africa's policy-making history had the security sector played such a major role. Regional relations changed subsequent to the policy changes because of the distorted vision the Botha regime had of black-ruled states. Namibia was seen as an important pawn in the Total National Strategy as the last buffer state in Southern Africa protecting South Africa's white minority regime
- Full Text:
- Date Issued: 1992
Geochemical and petrological trends in the UG2-Merensky unit interval of the upper critical zone in the Western Bushveld Complex
- Authors: Maier, Wolfgang Derek
- Date: 1992
- Subjects: Petrology -- South Africa -- North-western Transvaal Geochemistry -- South Africa -- North-western Transvaal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4951 , http://hdl.handle.net/10962/d1005563
- Description: One of the most remarkable features of the layered sequence of the Bushveld Complex is its lateral consistency in lithology. This work has established a geochemical and lithological correlation along 170 km of strike of the interval between the UG2 chromitite and the Merensky Reef within the Upper Critical zone of the western limb of the Bushveld Complex. The correlation is based on geochemical investigations of 10 borehole intersections and lithological comparisons of more than 20 borehole intersections around the western lobe of the complex. The basic data presented include 123 whole-rock analyses for major and 12 trace elements, 97 analyses for ' 12 trace elements, and ca. 5500 microprobe analyses of all major phases. Patterns of cryptic variation are established. Some layers (the UG2 chromitite and pyroxenite) show considerable consistency with regard to geochemistry and lithology. Others can be traced along most of the investigated strike length, such as the Lone Chrome Seam, the Footwall Marker anorthosite and the immediate anorthosite footwall to the Merensky Unit. Most of the distinguishable members within the study section, however, show great variation along strike (i.e., the Lower and Upper Pseudoreef Markers, the central noritic sequence in the southern arm of the western limb and parts of the immediate Merensky Reef footwall succession). Several models have been evaluated to interpret the geochemical and lithological data. The author comes to the conclusion that the degree of lithological consistency depends on the variability of magmatic parameters within different parts of the chamber. The most important of these parameters are: (i) the size of fresh primitive influxes and consequently the heat flux, (ii) the composition of the residual liquid, and (iii) the frequency of the influxes. Fresh influxes of more or less similar composition thus spread out along the floor if the residual liquid was less dense than the fresh primitive liquid, but intruded the chamber as a plume where plagioclase had crystallized for some time and the residual liquid had become relatively dense. The size of the influx may be regarded as a measure of the amount of heat flux from the feeder into the chamber. A large influx created uniform physicochemical conditions in the chamber whereas a smaller influx created a strong lateral gradient of physicochemical parameters in the chamber, with subsequent differences in viscosity, density, convection currents, yield strength and thus different mixing behaviour of different liquids. Furthermore, a persistent heat flux from the feeder may have delayed crystallization of successive phases in those parts of the chamber proximal to the feeder . Therefore, new influxes would have been deposited on a footwall of varying thickness and lithology in response to different degrees of crystallization and accumulation along strike. The development of a normal cyclic unit (chromititeharzburgite-pyroxenite-norite (+anorthosite?)) may thus have been interrupted at various stages in different parts of the chamber. The ability to correlate anorthosites over great strike distances implies that their formation did not follow entirely random processes but was dependent on specific magmatic conditions which prevailed over laterally extensive portions of the chamber at certain stages during the evolution of the crystallizing liquid.
- Full Text:
- Date Issued: 1992
- Authors: Maier, Wolfgang Derek
- Date: 1992
- Subjects: Petrology -- South Africa -- North-western Transvaal Geochemistry -- South Africa -- North-western Transvaal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4951 , http://hdl.handle.net/10962/d1005563
- Description: One of the most remarkable features of the layered sequence of the Bushveld Complex is its lateral consistency in lithology. This work has established a geochemical and lithological correlation along 170 km of strike of the interval between the UG2 chromitite and the Merensky Reef within the Upper Critical zone of the western limb of the Bushveld Complex. The correlation is based on geochemical investigations of 10 borehole intersections and lithological comparisons of more than 20 borehole intersections around the western lobe of the complex. The basic data presented include 123 whole-rock analyses for major and 12 trace elements, 97 analyses for ' 12 trace elements, and ca. 5500 microprobe analyses of all major phases. Patterns of cryptic variation are established. Some layers (the UG2 chromitite and pyroxenite) show considerable consistency with regard to geochemistry and lithology. Others can be traced along most of the investigated strike length, such as the Lone Chrome Seam, the Footwall Marker anorthosite and the immediate anorthosite footwall to the Merensky Unit. Most of the distinguishable members within the study section, however, show great variation along strike (i.e., the Lower and Upper Pseudoreef Markers, the central noritic sequence in the southern arm of the western limb and parts of the immediate Merensky Reef footwall succession). Several models have been evaluated to interpret the geochemical and lithological data. The author comes to the conclusion that the degree of lithological consistency depends on the variability of magmatic parameters within different parts of the chamber. The most important of these parameters are: (i) the size of fresh primitive influxes and consequently the heat flux, (ii) the composition of the residual liquid, and (iii) the frequency of the influxes. Fresh influxes of more or less similar composition thus spread out along the floor if the residual liquid was less dense than the fresh primitive liquid, but intruded the chamber as a plume where plagioclase had crystallized for some time and the residual liquid had become relatively dense. The size of the influx may be regarded as a measure of the amount of heat flux from the feeder into the chamber. A large influx created uniform physicochemical conditions in the chamber whereas a smaller influx created a strong lateral gradient of physicochemical parameters in the chamber, with subsequent differences in viscosity, density, convection currents, yield strength and thus different mixing behaviour of different liquids. Furthermore, a persistent heat flux from the feeder may have delayed crystallization of successive phases in those parts of the chamber proximal to the feeder . Therefore, new influxes would have been deposited on a footwall of varying thickness and lithology in response to different degrees of crystallization and accumulation along strike. The development of a normal cyclic unit (chromititeharzburgite-pyroxenite-norite (+anorthosite?)) may thus have been interrupted at various stages in different parts of the chamber. The ability to correlate anorthosites over great strike distances implies that their formation did not follow entirely random processes but was dependent on specific magmatic conditions which prevailed over laterally extensive portions of the chamber at certain stages during the evolution of the crystallizing liquid.
- Full Text:
- Date Issued: 1992
Environmental physiology of the intertidal limpets Patella (Prosobranchia) and Siphonaria (Pulmonata)
- Authors: Marshall, David John
- Date: 1992
- Subjects: Prosobranchia Pulmonata Patellidae Siphonaria Limpets
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5686 , http://hdl.handle.net/10962/d1005372
- Description: Physiological response to environmental change is examined in species of the intertidal limpets, Patella (Prosobranchia) and Siphonaria (Pulmonata). Characteristics of heart beat were determined using impedance pneumography and these are described. Heart rate of P. granularis is related to temperature and body size, and cardiac arrest in this limpet is apparently stress-related. Siphonaria oculus may exhibit a temperature-independent, extreme, and often prolonged bradycardia (<10 beats/min). When measured shortly after aerial exposure, heart rate and oxygen consumption of the above limpet species are closely correlated. The relationships of aerial oxygen consumption with body weight and ambient temperature were determined for the above high shore species of limpet. Both have low aerial rates of oxygen consumption relative to low shore limpet species, and their QlO values decrease with increasing temperature. Diel field recordings of heart rate of S. oculus, taken during summer and winter, suggest absence of temperature acclimation, and this was also shown for oxygen consumption at high aerial temperatures (30°C) in laboratory experiments. Oxygen consumption of P. granularis is partially temperature compensated temperature acclimation). In air, even though S. oculus loses water faster, it shows greater tolerance of water loss and survives longer than P. granularis. Prolonged aerial exposure of S. oculus leads to depression of heart rate and of V02 (down to 18% of the pre-exposure rate), responses interpreted as representing adaptive metabolic rate depression. In P. granularis aerial heart rate remains constant and V02 never falls below IX 38% of pre-exposure rate. This reduction in V02 in air is considered as being stress-related, resulting from impairment of oxygen uptake. In declining oxygen tension S. capensis shows a better capacity for oxyregulation than P. granularis. On exposure to hypoxia, sand-inundation and hyposalinity, S. capensis may show typical bradycardia ( <10 beats/min), suggesting depression of aerobic metabolism, and on return to pre-exposure conditions there is no overshoot of heart rate, suggesting absence of oxygen debt. The effect of hypoxia, sand-inundation and hyposalinity on heart rate of P. granularis is variable; this becomes depressed and is often interspersed with extended cardiac arrest. When conditions are normalized, this species exhibits a clear overshoot of heart rate. The significance of differences in physiological response between patellid and siphonariid limpets is discussed with regard to their habitat segregation, particularly in the upper-shore zone (open rock and tidal pools) and sand-inundated rock substrata, where only siphonariid limpets may be found. While not previously characterized in marine gastropods, metabolic rate depression by Siphonaria, through facilitating isolation and conserving food reserves, is suggested as a key factor determining their distribution in physico-chemically more extreme and variable intertidal habitats.
- Full Text:
- Date Issued: 1992
- Authors: Marshall, David John
- Date: 1992
- Subjects: Prosobranchia Pulmonata Patellidae Siphonaria Limpets
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5686 , http://hdl.handle.net/10962/d1005372
- Description: Physiological response to environmental change is examined in species of the intertidal limpets, Patella (Prosobranchia) and Siphonaria (Pulmonata). Characteristics of heart beat were determined using impedance pneumography and these are described. Heart rate of P. granularis is related to temperature and body size, and cardiac arrest in this limpet is apparently stress-related. Siphonaria oculus may exhibit a temperature-independent, extreme, and often prolonged bradycardia (<10 beats/min). When measured shortly after aerial exposure, heart rate and oxygen consumption of the above limpet species are closely correlated. The relationships of aerial oxygen consumption with body weight and ambient temperature were determined for the above high shore species of limpet. Both have low aerial rates of oxygen consumption relative to low shore limpet species, and their QlO values decrease with increasing temperature. Diel field recordings of heart rate of S. oculus, taken during summer and winter, suggest absence of temperature acclimation, and this was also shown for oxygen consumption at high aerial temperatures (30°C) in laboratory experiments. Oxygen consumption of P. granularis is partially temperature compensated temperature acclimation). In air, even though S. oculus loses water faster, it shows greater tolerance of water loss and survives longer than P. granularis. Prolonged aerial exposure of S. oculus leads to depression of heart rate and of V02 (down to 18% of the pre-exposure rate), responses interpreted as representing adaptive metabolic rate depression. In P. granularis aerial heart rate remains constant and V02 never falls below IX 38% of pre-exposure rate. This reduction in V02 in air is considered as being stress-related, resulting from impairment of oxygen uptake. In declining oxygen tension S. capensis shows a better capacity for oxyregulation than P. granularis. On exposure to hypoxia, sand-inundation and hyposalinity, S. capensis may show typical bradycardia ( <10 beats/min), suggesting depression of aerobic metabolism, and on return to pre-exposure conditions there is no overshoot of heart rate, suggesting absence of oxygen debt. The effect of hypoxia, sand-inundation and hyposalinity on heart rate of P. granularis is variable; this becomes depressed and is often interspersed with extended cardiac arrest. When conditions are normalized, this species exhibits a clear overshoot of heart rate. The significance of differences in physiological response between patellid and siphonariid limpets is discussed with regard to their habitat segregation, particularly in the upper-shore zone (open rock and tidal pools) and sand-inundated rock substrata, where only siphonariid limpets may be found. While not previously characterized in marine gastropods, metabolic rate depression by Siphonaria, through facilitating isolation and conserving food reserves, is suggested as a key factor determining their distribution in physico-chemically more extreme and variable intertidal habitats.
- Full Text:
- Date Issued: 1992
A polarimetric method for collagenase activity measurement
- Brüning, Adrian Rudolf Nicolaus Ernst
- Authors: Brüning, Adrian Rudolf Nicolaus Ernst
- Date: 1992
- Subjects: Collagenases -- Research , Hides and skins -- Preservation -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4052 , http://hdl.handle.net/10962/d1004113 , Collagenases -- Research , Hides and skins -- Preservation -- Research
- Description: A polarimetric method for monitoring the rate of soluble collagen breakdown by collagenase enzyme action has been developed. The method represents an extension of previous physicochemical techniques based on viscometry, but is simpler and easier to carry out, particularly in the case of reaction rate studies. The method was developed arising from reports of collagenase activity measurement on inappropriate substrates such as gelatin, modified collagens and synthetic polypeptides. The optical method depends on measurement of the loss in optical rotation in solutions of soluble calfskin collagen resulting from initial enzymic cleavage of the collagen trip1e-helix, followed by spontaneous unwinding of the resultant unstable helical fragments. Specific assay conditions were chosen to ensure that the loss in optical rotation following enzymic cleavage was rapid and complete. The method is specific since in the absence of collagenase, non-specific proteinases produce only a limited decrease in solution optical activity. The method has also been compared with established physicochemical assay techniques and compares favourably with both viscometric and titrimetric collagenase assays. The availability of a rapid, sensitive and quantitative procedure for measurement of collagenase activity provides a convenient means for detecting the presence of collagenase in solution and examination of hide bacterial cultures for collagenase production. In addition, a study of biocidal compounds of potential interest in hide preservation for possible inhibitory effects on collagenase is conveniently carried out with the method. Fundamental research into synergistic action in enzymic hydrolysis of collagen is now possible, providing valuable insight into the mechanism of raw hide biodeterioration.
- Full Text:
- Date Issued: 1992
- Authors: Brüning, Adrian Rudolf Nicolaus Ernst
- Date: 1992
- Subjects: Collagenases -- Research , Hides and skins -- Preservation -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4052 , http://hdl.handle.net/10962/d1004113 , Collagenases -- Research , Hides and skins -- Preservation -- Research
- Description: A polarimetric method for monitoring the rate of soluble collagen breakdown by collagenase enzyme action has been developed. The method represents an extension of previous physicochemical techniques based on viscometry, but is simpler and easier to carry out, particularly in the case of reaction rate studies. The method was developed arising from reports of collagenase activity measurement on inappropriate substrates such as gelatin, modified collagens and synthetic polypeptides. The optical method depends on measurement of the loss in optical rotation in solutions of soluble calfskin collagen resulting from initial enzymic cleavage of the collagen trip1e-helix, followed by spontaneous unwinding of the resultant unstable helical fragments. Specific assay conditions were chosen to ensure that the loss in optical rotation following enzymic cleavage was rapid and complete. The method is specific since in the absence of collagenase, non-specific proteinases produce only a limited decrease in solution optical activity. The method has also been compared with established physicochemical assay techniques and compares favourably with both viscometric and titrimetric collagenase assays. The availability of a rapid, sensitive and quantitative procedure for measurement of collagenase activity provides a convenient means for detecting the presence of collagenase in solution and examination of hide bacterial cultures for collagenase production. In addition, a study of biocidal compounds of potential interest in hide preservation for possible inhibitory effects on collagenase is conveniently carried out with the method. Fundamental research into synergistic action in enzymic hydrolysis of collagen is now possible, providing valuable insight into the mechanism of raw hide biodeterioration.
- Full Text:
- Date Issued: 1992
The biology of four haplochromine species of Lake Kivu (Zaïre) with evolutionary implications
- Authors: Losseau-Hoebeke, Michèle
- Date: 1992
- Subjects: Cichlids -- Research -- Kivu, Lake (Congo and Rwanda) , Cichlids -- Ecology -- Research , Cichlids -- Breeding -- Research , Cichlids -- Evolution -- Research , Haplochromis -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5239 , http://hdl.handle.net/10962/d1005082 , Cichlids -- Research -- Kivu, Lake (Congo and Rwanda) , Cichlids -- Ecology -- Research , Cichlids -- Breeding -- Research , Cichlids -- Evolution -- Research , Haplochromis -- Research
- Description: Four species were selected within the littoral of Tshegera Island, and include H. astatodon, H. olivaceus, H. crebridens and H. paucidens. These species, identified on basis of the SMRS, express their individuality most strongly with respect to dentition, breeding colours, normal habitat and preferred breeding territory. All four species are maternal mouthbrooders. This reproductive strategy is characterized by complete division of labour and polygamy. Breeding males compete for optimal territories and ready to spawn females. They are characterized by fast growth, large size and overall low condition factor. Females invest in few but large yolked ova and go through a fasting period while incubating the eggs. Females are generally characterized by slower growth, smaller size and higher condition factor when compared to males. In females the energy turnover during gonadal development and subsequent mouthbrooding is high, but the energy expenditure low. Mean fecundity varies between 25 and 36 eggs per brood and mean egg size between 2.6 and 2.7 rnrn. The right ovary, although small, is functional. Breeding of variable intensity goes on throughout the year. The main dry season corresponds to synchronized breeding. During the other months of the year species breed asynchronously. Both types of breeding are related to food availability for adults and offspring. The major breeding peak which starts in July coincides to improved body condition in both sexes. In similarity with the East African flocks, the Lake Kivu haplochromines display subdivision within the major trophic groups and invasion of the major lacustrine habitats. They are nevertheless morphologically and ecologically generalized. They tend to be plesiomorphic with low diversification within each trophic group, have a lake wide distribution (eurytopic) and incline to be altricial within their specialized reproductive guild. The evolutionary status of the Lake Kivu haplochromines may be explained by survival of members of an ancestral fauna in an isolated bay during the Recent volcanic events which destroyed life in the Main Basin. The Lake Kivu flock, therefore, is a relict and is believed not to have evolved within the confines of the present-day lake.
- Full Text:
- Date Issued: 1992
- Authors: Losseau-Hoebeke, Michèle
- Date: 1992
- Subjects: Cichlids -- Research -- Kivu, Lake (Congo and Rwanda) , Cichlids -- Ecology -- Research , Cichlids -- Breeding -- Research , Cichlids -- Evolution -- Research , Haplochromis -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5239 , http://hdl.handle.net/10962/d1005082 , Cichlids -- Research -- Kivu, Lake (Congo and Rwanda) , Cichlids -- Ecology -- Research , Cichlids -- Breeding -- Research , Cichlids -- Evolution -- Research , Haplochromis -- Research
- Description: Four species were selected within the littoral of Tshegera Island, and include H. astatodon, H. olivaceus, H. crebridens and H. paucidens. These species, identified on basis of the SMRS, express their individuality most strongly with respect to dentition, breeding colours, normal habitat and preferred breeding territory. All four species are maternal mouthbrooders. This reproductive strategy is characterized by complete division of labour and polygamy. Breeding males compete for optimal territories and ready to spawn females. They are characterized by fast growth, large size and overall low condition factor. Females invest in few but large yolked ova and go through a fasting period while incubating the eggs. Females are generally characterized by slower growth, smaller size and higher condition factor when compared to males. In females the energy turnover during gonadal development and subsequent mouthbrooding is high, but the energy expenditure low. Mean fecundity varies between 25 and 36 eggs per brood and mean egg size between 2.6 and 2.7 rnrn. The right ovary, although small, is functional. Breeding of variable intensity goes on throughout the year. The main dry season corresponds to synchronized breeding. During the other months of the year species breed asynchronously. Both types of breeding are related to food availability for adults and offspring. The major breeding peak which starts in July coincides to improved body condition in both sexes. In similarity with the East African flocks, the Lake Kivu haplochromines display subdivision within the major trophic groups and invasion of the major lacustrine habitats. They are nevertheless morphologically and ecologically generalized. They tend to be plesiomorphic with low diversification within each trophic group, have a lake wide distribution (eurytopic) and incline to be altricial within their specialized reproductive guild. The evolutionary status of the Lake Kivu haplochromines may be explained by survival of members of an ancestral fauna in an isolated bay during the Recent volcanic events which destroyed life in the Main Basin. The Lake Kivu flock, therefore, is a relict and is believed not to have evolved within the confines of the present-day lake.
- Full Text:
- Date Issued: 1992
Umgangxo wentombi
- Date: 1955-03-03 , 2023-09-01
- Subjects: Beadwork , Body harness
- Language: English
- Type: realia , Personal adornment
- Identifier: http://hdl.handle.net/11260/8653 , vital:68068
- Description: Umgangxo wentombi, A body harness of a girl of flat bead strips and bead chains, worn by a girl,The body harness forms part of beadwork collection that was acquired from Mrs Broster in 1992. , Purchased from Mrs Joan Broster , Forms part of: Walter Sisulu University Beadwork Collection
- Full Text: false
- Date Issued: 1955-03-03
- Date: 1955-03-03 , 2023-09-01
- Subjects: Beadwork , Body harness
- Language: English
- Type: realia , Personal adornment
- Identifier: http://hdl.handle.net/11260/8653 , vital:68068
- Description: Umgangxo wentombi, A body harness of a girl of flat bead strips and bead chains, worn by a girl,The body harness forms part of beadwork collection that was acquired from Mrs Broster in 1992. , Purchased from Mrs Joan Broster , Forms part of: Walter Sisulu University Beadwork Collection
- Full Text: false
- Date Issued: 1955-03-03
Project water (Grahamstown) : a case study of the development of an environmental education project
- Authors: Ashwell, Alice Nicola
- Date: 1992
- Subjects: Environmental education -- Study and teaching (Secondary) -- South Africa Environmental education -- Activity programs -- South Africa Water quality -- Measurement Water conservation -- South Africa Water-supply -- South Africa -- Grahamstown Global Rivers Environmental Education Network Project Water (Grahamstown) Water -- Pollution -- Environmental aspects Water -- Pollution -- South Africa -- Grahamstown Schools -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1716 , http://hdl.handle.net/10962/d1003599
- Description: Environmental education is an approach to education which emphasises the interrelatedness of people and their human and non-human environments and seeks to encourage environmental awareness, concern and action. This case study documents the implementation and development of Project WATER, Grahamstown, a practical environmental education project dealing with catchment conservation and water quality monitoring. The Grahamstown project is one of a number of local water quality monitoring initiatives affiliated to GREEN (the Global Rivers Environmental Education Network). Participants in the project included student teachers from the Department of Education at Rhodes University and pupils and teachers from three farm schools in the district and four high schools in the town. Project WATER, Grahamstown developed as an Action Research and Community Problem-Solving project. The study focuses on fragmentalist and holistic approaches to education, people's responses to Project WATER and the choice of action research as the research method.
- Full Text:
- Date Issued: 1992
- Authors: Ashwell, Alice Nicola
- Date: 1992
- Subjects: Environmental education -- Study and teaching (Secondary) -- South Africa Environmental education -- Activity programs -- South Africa Water quality -- Measurement Water conservation -- South Africa Water-supply -- South Africa -- Grahamstown Global Rivers Environmental Education Network Project Water (Grahamstown) Water -- Pollution -- Environmental aspects Water -- Pollution -- South Africa -- Grahamstown Schools -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1716 , http://hdl.handle.net/10962/d1003599
- Description: Environmental education is an approach to education which emphasises the interrelatedness of people and their human and non-human environments and seeks to encourage environmental awareness, concern and action. This case study documents the implementation and development of Project WATER, Grahamstown, a practical environmental education project dealing with catchment conservation and water quality monitoring. The Grahamstown project is one of a number of local water quality monitoring initiatives affiliated to GREEN (the Global Rivers Environmental Education Network). Participants in the project included student teachers from the Department of Education at Rhodes University and pupils and teachers from three farm schools in the district and four high schools in the town. Project WATER, Grahamstown developed as an Action Research and Community Problem-Solving project. The study focuses on fragmentalist and holistic approaches to education, people's responses to Project WATER and the choice of action research as the research method.
- Full Text:
- Date Issued: 1992
A study of the role of nature conservation law enforcement officers as facilitators of environmental education
- Authors: Barrett, Janice Anne
- Date: 1992
- Subjects: Environmental education Nature conservation
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1783 , http://hdl.handle.net/10962/d1003668
- Description: This study explores the potential roles of a sample of 18 nature conservation law enforcement officers, as facilitators of environmental education. More specifically it examines their attitudes towards their dual duties of enforcing laws and providing extension services. Attitudes were examined by means of qualitative data analysis from semi-structured interviews. Officers' environmental attitudes, as well the relative emphasis placed on law enforcement and extension, and their own perspectives of working with communities, are explored. The historical and cultural context of officers' work, as well as worldviews and personality traits are also discussed. Certain recommendations regarding officers' roles as facilitors of environmental education are made.
- Full Text:
- Date Issued: 1992
- Authors: Barrett, Janice Anne
- Date: 1992
- Subjects: Environmental education Nature conservation
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1783 , http://hdl.handle.net/10962/d1003668
- Description: This study explores the potential roles of a sample of 18 nature conservation law enforcement officers, as facilitators of environmental education. More specifically it examines their attitudes towards their dual duties of enforcing laws and providing extension services. Attitudes were examined by means of qualitative data analysis from semi-structured interviews. Officers' environmental attitudes, as well the relative emphasis placed on law enforcement and extension, and their own perspectives of working with communities, are explored. The historical and cultural context of officers' work, as well as worldviews and personality traits are also discussed. Certain recommendations regarding officers' roles as facilitors of environmental education are made.
- Full Text:
- Date Issued: 1992
Isiyeye for young adults
- Date: 1959-01-12 , 2023-09-01
- Subjects: Beadwork , Necklace
- Language: English
- Type: realia , Personal adornment
- Identifier: http://hdl.handle.net/11260/8623 , vital:68060
- Description: Isiyeye for young adults,A white bead strip neck band with navy triangles and lines a yellow edge and fringe, Decorated with 6 white and navy streamers and a pearl button, Yellow denotes fertility and wish for many children, Worn by young adults, The necklace forms part of beadwork collection that was acquired from Mrs Broster in 1992. , Purchased from Mrs Joan Broster , Forms part of: Walter Sisulu University Beadwork Collection
- Full Text: false
- Date Issued: 1959-01-12
- Date: 1959-01-12 , 2023-09-01
- Subjects: Beadwork , Necklace
- Language: English
- Type: realia , Personal adornment
- Identifier: http://hdl.handle.net/11260/8623 , vital:68060
- Description: Isiyeye for young adults,A white bead strip neck band with navy triangles and lines a yellow edge and fringe, Decorated with 6 white and navy streamers and a pearl button, Yellow denotes fertility and wish for many children, Worn by young adults, The necklace forms part of beadwork collection that was acquired from Mrs Broster in 1992. , Purchased from Mrs Joan Broster , Forms part of: Walter Sisulu University Beadwork Collection
- Full Text: false
- Date Issued: 1959-01-12
Geological controls for coal exploration and mining
- Authors: Noppé , Mark Adrian
- Date: 1992
- Subjects: Coal -- Geology , Coal mines and mining
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4954 , http://hdl.handle.net/10962/d1005566 , Coal -- Geology , Coal mines and mining
- Description: The identification and interpretation of geological features is essential for the planning and ultimate success of any mining venture. Examples of geological features significant for mining are presented, and their identification during exploration discussed. In particular, the importance of coal qualities, seam thickness and seam elevation are emphasised in relation to longwall mining. Geostatistical analysis provides a powerful tool for improving the prediction and decision-making capabilities of both exploration and mine geologists. The availability of geostatistics, and the benefits resulting from its application, are demonstrated using actual data for calorific value, seam thickness and seam elevation. Contamination of run-of-mine coal is a common problem on highly-mechanised collieries. The problem generally arises from over-cutting of the designated mining horizon. A practical system for monitoring and controlling contamination on a mechanised bord-and-pillar and longwall colliery is presented. The results and benefits of applying such a system are cited for an actual longwall colliery. Numerical geological predictions are not always reported in terms of the reliability of such estimates. Many of these values can be reported in terms of confidence limits, particularly for routine grade control purposes. The methods and benefits of such reporting are described and illustrated by way of examples for calorific value and contamination levels.
- Full Text:
- Date Issued: 1992
- Authors: Noppé , Mark Adrian
- Date: 1992
- Subjects: Coal -- Geology , Coal mines and mining
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4954 , http://hdl.handle.net/10962/d1005566 , Coal -- Geology , Coal mines and mining
- Description: The identification and interpretation of geological features is essential for the planning and ultimate success of any mining venture. Examples of geological features significant for mining are presented, and their identification during exploration discussed. In particular, the importance of coal qualities, seam thickness and seam elevation are emphasised in relation to longwall mining. Geostatistical analysis provides a powerful tool for improving the prediction and decision-making capabilities of both exploration and mine geologists. The availability of geostatistics, and the benefits resulting from its application, are demonstrated using actual data for calorific value, seam thickness and seam elevation. Contamination of run-of-mine coal is a common problem on highly-mechanised collieries. The problem generally arises from over-cutting of the designated mining horizon. A practical system for monitoring and controlling contamination on a mechanised bord-and-pillar and longwall colliery is presented. The results and benefits of applying such a system are cited for an actual longwall colliery. Numerical geological predictions are not always reported in terms of the reliability of such estimates. Many of these values can be reported in terms of confidence limits, particularly for routine grade control purposes. The methods and benefits of such reporting are described and illustrated by way of examples for calorific value and contamination levels.
- Full Text:
- Date Issued: 1992
The utilization of tilting-filter photometry in airglow and auroral research
- Authors: Dore, Ian Stuart
- Date: 1992
- Subjects: Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5494 , http://hdl.handle.net/10962/d1005280 , Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Description: This thesis describes the application of tilting-filter photometry to the study of the airglow and aurora. Previous South African photometric research is reviewed. Optical instrumentation and techniques used in airglow and auroral research are reviewed. The transmission characteristics of narrowband interference filters are discussed. The analogue meridian-scanning tilting-filter photometry system used at Sanae, Antarctica is described. Shortcomings of this system have been identified, and modifications have been made to improve its spatial and temporal resolution. Details are given of the computer-controlled digital photometry system which replaced the analogue system. Equations are derived for the conversion of raw photometric data (analogue chart deflections or digital photon counts) to absolute emission intensities. The accuracy of the intensities obtained depends on the absolute calibration of the photometer, the transmission characteristics of the filter used to isolate the spectral feature of interest, and the effects of atmospheric extinction and scattering. The influence of these factors on observed emission intensities is discussed. Various models used to determine atmospheric correction factors are reviewed. It is shown that atmospheric correction factors can have a significant effect on both emission intensities and intensity ratios. The procedure used to determine the transmission characteristics of interference filters is described, as is the procedure used to cross-calibrate secondary light sources. The transmission characteristics of the filters and the brightnesses of the light sources were both found to have changed appreciably with age. The observation of a magnetospheric substorm at Sanae (L ≃ 4) is used to illustrate the use of a meridian-scanning tilting-filter photometer system in auroral research. The ratio I(557.7)/ I(391.4) observed at Sanae was found to be lower than expected, as were the OJ airglow emission intensities. A prototype digital photometer system was used aboard a ship, to observe the airglow in the region of the South Atlantic Anomaly. Significant N₂⁺ lNG emissions at 391.4 nm were measured, confirming the presence of discernable particle precipitation in the region. The 0I557.7 and 630.0 nm intensities measured from the ship were found to be lower than expected. This, combined with low airglow and auroral intensities measured at Sanae, is a cause for concern. It is recommended that further checks be made regarding the brightness of the calibration sources.
- Full Text:
- Date Issued: 1992
- Authors: Dore, Ian Stuart
- Date: 1992
- Subjects: Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5494 , http://hdl.handle.net/10962/d1005280 , Photometry -- Research , Airglow -- Research , Auroras -- Research , Auroral photography -- Research
- Description: This thesis describes the application of tilting-filter photometry to the study of the airglow and aurora. Previous South African photometric research is reviewed. Optical instrumentation and techniques used in airglow and auroral research are reviewed. The transmission characteristics of narrowband interference filters are discussed. The analogue meridian-scanning tilting-filter photometry system used at Sanae, Antarctica is described. Shortcomings of this system have been identified, and modifications have been made to improve its spatial and temporal resolution. Details are given of the computer-controlled digital photometry system which replaced the analogue system. Equations are derived for the conversion of raw photometric data (analogue chart deflections or digital photon counts) to absolute emission intensities. The accuracy of the intensities obtained depends on the absolute calibration of the photometer, the transmission characteristics of the filter used to isolate the spectral feature of interest, and the effects of atmospheric extinction and scattering. The influence of these factors on observed emission intensities is discussed. Various models used to determine atmospheric correction factors are reviewed. It is shown that atmospheric correction factors can have a significant effect on both emission intensities and intensity ratios. The procedure used to determine the transmission characteristics of interference filters is described, as is the procedure used to cross-calibrate secondary light sources. The transmission characteristics of the filters and the brightnesses of the light sources were both found to have changed appreciably with age. The observation of a magnetospheric substorm at Sanae (L ≃ 4) is used to illustrate the use of a meridian-scanning tilting-filter photometer system in auroral research. The ratio I(557.7)/ I(391.4) observed at Sanae was found to be lower than expected, as were the OJ airglow emission intensities. A prototype digital photometer system was used aboard a ship, to observe the airglow in the region of the South Atlantic Anomaly. Significant N₂⁺ lNG emissions at 391.4 nm were measured, confirming the presence of discernable particle precipitation in the region. The 0I557.7 and 630.0 nm intensities measured from the ship were found to be lower than expected. This, combined with low airglow and auroral intensities measured at Sanae, is a cause for concern. It is recommended that further checks be made regarding the brightness of the calibration sources.
- Full Text:
- Date Issued: 1992
The psychological sequelae of involvement in combat: a preliminary investigation
- Authors: Hodgson, Shane Ralph Colin
- Date: 1992
- Subjects: War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:2993 , http://hdl.handle.net/10962/d1002502 , War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Description: The psychological sequelae of being involved in combat are only recently coming to be understood. Most of the available data are from research conducted on help-seeking Vietnam veterans in the United States, and very little work has been done in South Africa. There does not as yet appear to be any instrument designed specifically to detect combat-related psychopathologies amongst soldiers who are still in active service, either in the USA or in South Africa. Combat involvement has been shown to lead to a high incidence of combat stress reaction. This in turn has shown that it can predispose sufferers to the development of a Post-traumatic Stress Disorder. It is thus expected that there would be significantly higher incidences of reported symptoms of stress disorders amongst soldiers exposed to high levels of combat as compared with a similar group of soldiers who had no combat involvement. This study used a self-reporting questionnaire, developed in the USA but adapted for use in South Africa, to allow the soldiers in the study to rate the severity of various symptoms derived from the DSM-III criteria for Post-traumatic Stress Disorder. A Beck Depression Inventory was also administered to eliminate any persons who nay have been exhibiting symptoms of depression, as this would have confounded the results. Both questionnaires were administered to serving members of the Permanent Force of the South African Defence Force, with one group being members of various high-combat units based in what was then South West Africa, and the other group being non-combat or Headquarters elements. As a precondition of the study, absolute confidentiality of the respondents and their units was maintained. The study found the expected higher scores in the high-combat group, and also showed that the Keane questionnaire has a good coefficient alpha in South Africa. The study closes with several recommendations for further research, especially in the light of the new PTSD criteria in the DSM-IIIR.
- Full Text:
- Date Issued: 1992
- Authors: Hodgson, Shane Ralph Colin
- Date: 1992
- Subjects: War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:2993 , http://hdl.handle.net/10962/d1002502 , War -- Psychological aspects , War victims -- Mental health , Post-traumatic stress disorder
- Description: The psychological sequelae of being involved in combat are only recently coming to be understood. Most of the available data are from research conducted on help-seeking Vietnam veterans in the United States, and very little work has been done in South Africa. There does not as yet appear to be any instrument designed specifically to detect combat-related psychopathologies amongst soldiers who are still in active service, either in the USA or in South Africa. Combat involvement has been shown to lead to a high incidence of combat stress reaction. This in turn has shown that it can predispose sufferers to the development of a Post-traumatic Stress Disorder. It is thus expected that there would be significantly higher incidences of reported symptoms of stress disorders amongst soldiers exposed to high levels of combat as compared with a similar group of soldiers who had no combat involvement. This study used a self-reporting questionnaire, developed in the USA but adapted for use in South Africa, to allow the soldiers in the study to rate the severity of various symptoms derived from the DSM-III criteria for Post-traumatic Stress Disorder. A Beck Depression Inventory was also administered to eliminate any persons who nay have been exhibiting symptoms of depression, as this would have confounded the results. Both questionnaires were administered to serving members of the Permanent Force of the South African Defence Force, with one group being members of various high-combat units based in what was then South West Africa, and the other group being non-combat or Headquarters elements. As a precondition of the study, absolute confidentiality of the respondents and their units was maintained. The study found the expected higher scores in the high-combat group, and also showed that the Keane questionnaire has a good coefficient alpha in South Africa. The study closes with several recommendations for further research, especially in the light of the new PTSD criteria in the DSM-IIIR.
- Full Text:
- Date Issued: 1992