Geographically distributed requirements elicitation
- Authors: Vat, Nicholas
- Date: 2000
- Subjects: Management information systems -- Management , Information resources management , System design , System analysis
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1136 , http://hdl.handle.net/10962/d1002764 , Management information systems -- Management , Information resources management , System design , System analysis
- Description: The technology revolution has transformed the way in which many organisations do their business. The resultant information systems have increased the decision making powers of executives, leading to increased effectiveness and ultimately to improved product delivery. The process of information systems development is, however, complex. Furthermore, it has a poor track record in terms of on-time and within-budget delivery, but more significantly in terms of low user acceptance frequently attributable to poor user requirements specification. Consequently, much attention has been given to the process of requirements elicitation, with both researchers and businessmen seeking new, innovative and effective methods. These methods usually involve large numbers of participants who are drawn from within the client and developer organisations. This is a financially costly characteristic of the requirements elicitation process. Besides information systems, the technology revolution has also brought sophisticated communication technologies into the marketplace. These communication technologies allow people to communicate with one another in a variety of different time and space scenarios. An important spin-off of this is the ability for people located in significantly different geographical locations to work collaboratively on a project. It is claimed that this approach to work has significant cost and productivity advantages. This study draws the requirements elicitation process into the realm of collaborative work. Important project management, communication, and collaborative working principles are examined in detail, and a model is developed which represents these issues as they pertain to the requirements elicitation process. An empirical study (conducted in South Africa) is performed in order to examine the principles of the model and the relationships between its constituent elements. A model of geographically distributed requirements elicitation (GDRE) is developed on the basis of the findings of this investigation. The model of GDRE is presented as a 3-phased approach to requirements elicitation, namely planning, implementation, and termination. Significantly, the model suggests the use of interviews, structured workshops, and prototyping as the chief requirements elicitation methods to be adopted in appropriate conditions. Although a detailed study of communications technology was not performed, this thesis suggests that each individual GDRE implementation requires a different mix of communication technologies to support its implementation.
- Full Text:
- Authors: Vat, Nicholas
- Date: 2000
- Subjects: Management information systems -- Management , Information resources management , System design , System analysis
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1136 , http://hdl.handle.net/10962/d1002764 , Management information systems -- Management , Information resources management , System design , System analysis
- Description: The technology revolution has transformed the way in which many organisations do their business. The resultant information systems have increased the decision making powers of executives, leading to increased effectiveness and ultimately to improved product delivery. The process of information systems development is, however, complex. Furthermore, it has a poor track record in terms of on-time and within-budget delivery, but more significantly in terms of low user acceptance frequently attributable to poor user requirements specification. Consequently, much attention has been given to the process of requirements elicitation, with both researchers and businessmen seeking new, innovative and effective methods. These methods usually involve large numbers of participants who are drawn from within the client and developer organisations. This is a financially costly characteristic of the requirements elicitation process. Besides information systems, the technology revolution has also brought sophisticated communication technologies into the marketplace. These communication technologies allow people to communicate with one another in a variety of different time and space scenarios. An important spin-off of this is the ability for people located in significantly different geographical locations to work collaboratively on a project. It is claimed that this approach to work has significant cost and productivity advantages. This study draws the requirements elicitation process into the realm of collaborative work. Important project management, communication, and collaborative working principles are examined in detail, and a model is developed which represents these issues as they pertain to the requirements elicitation process. An empirical study (conducted in South Africa) is performed in order to examine the principles of the model and the relationships between its constituent elements. A model of geographically distributed requirements elicitation (GDRE) is developed on the basis of the findings of this investigation. The model of GDRE is presented as a 3-phased approach to requirements elicitation, namely planning, implementation, and termination. Significantly, the model suggests the use of interviews, structured workshops, and prototyping as the chief requirements elicitation methods to be adopted in appropriate conditions. Although a detailed study of communications technology was not performed, this thesis suggests that each individual GDRE implementation requires a different mix of communication technologies to support its implementation.
- Full Text:
The evolution of the Brosterlea Volcanic Complex, Eastern Cape, South Africa
- Authors: Surtees, Grant Bradley
- Date: 2000
- Subjects: Volcanism , Geology -- South Africa -- Eastern Cape -- Brosterlea Volcanic Complex , Geology -- South Africa -- Eastern Cape , Flood basalts , Geology, Structural -- South Africa , Formations (Geology) -- South Africa , Geology, Structural -- Maps , Geological mapping
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4944 , http://hdl.handle.net/10962/d1005556 , Volcanism , Geology -- South Africa -- Eastern Cape -- Brosterlea Volcanic Complex , Geology -- South Africa -- Eastern Cape , Flood basalts , Geology, Structural -- South Africa , Formations (Geology) -- South Africa , Geology, Structural -- Maps , Geological mapping
- Description: Detailed field mapping (Map, Appendix B) has been conducted in and around the boundaries of a 14x18km, volcanic complex 35km northeast of Molteno in the Eastern Cape Province, South Africa. The structure is interpreted as a subsidence structure, and is filled with two volcaniclastic breccias, numerous lava flows, a number of sedimentary facies, and lies on a base of Clarens Formation overlying Elliot Formation rocks. This is an important study because 'widespread, voluminous fields of basaltic breccias are very rare (see Hanson and Elliot, 1996) and this is the first time that this type of volcanic complex and its deposits have been described. Detailed analyses of the two volcaniclastic breccias revealed changes in colour, clast types, clast sizes, and degree of alteration over relatively short distances both vertically and laterally within a single breccia unit. The variation in clast sizes implies a lack of sorting of the breccias. The lower of the two volcaniclastic breccias fills the subsidence structure, and outcrops between the Stormberg sedimentary sequence and the overlying Drakensberg basalts and was produced from phreatomagmatic eruptions signalling the start of the break-up of Gondwanaland in the mid-Jurassic. The upper volcaniclastic breccia is interbedded with the flood basalts and is separated from the lower breccia by up to 100m of lava flows in places, it is finer-grained than the lower volcaniclastic breccia, and it extends over 10km south, and over 100km north from the volcanic complex. The upper breccia is inferred to have been transported from outside the study area, from a source presumably similar to the subsidence structure in the volcanic complex. The pyroclastic material forming the upper breccia was transported to the subsidence structure as a laharic debris flow, based on its poorly sorted, unwelded and matrix-supported appearance. However, both breccias are unlikely to have been derived from epiclastic reworking of lava flows as they contain glass shards which are atypical of those derived from the autoclastic component of lava flows. The breccias are therefore not "secondary" lahars. There is also no evidence of any palaeotopographic highs from which the breccias could have been derived as gravity-driven flows. Based on the occurrence of three, 1m thick lacustrine deposits, localised peperite, fluvial reworking of sandstone and breccia in an outcrop to the south of the subsidence structure, and channel-lags encountered only in the upper units of the Clarens Formation and only within the subsidence structure, the palaeoenvironment inferred for the subsidence structure is one of wet sediment, possibly a shallow lake, in a topographic depression fed by small streams. Magmatic intrusions below the subsidence structure heated the water-laden, partly consolidated Clarens Formation sandstones, causing the circulation of pore fluid which resulted in the precipitation of minerals forming pisoliths in the sandstones. Intruding magma mixed, nonexplosively, with the wet, unconsolidated sediments near the base of the Clarens Formation (at approximately 100m below the surface), forming fluidal peperite by a process of sediment fluidisation where magma replaces wet sediment and cools slowly enough to prevent the magma fracturing brittly. Formation of fluidal peperite may have been a precursor to the development of FCIs (Fuel Coolant Interactions) (Busby-Spera and White, 1987). The breccias may represent the products of FCIs and may be the erupted equivalents of the peperites, suggesting a possible genetic link between the two. The peperites may have given way to FCI eruptions due to a number of factors including the drying out of the sediments and/or an increase in the volume of intruded magma below the subsidence structure which may have resulted in a more explosive interaction between sediment and magma. Phreatic activity fragmented and erupted the Clarens Formation sandstone, and stream flows reworked the angular sandstone fragments, pisoliths and sand grains into channelised deposits. With an increase in magmatic activity below the subsidence structure, phreatic activity became phreatomagmatic. The wet, partly consolidated Clarens Formation, and underlying, fully consolidated Elliot Formation sediments were erupted and fragmented. Clasts and individual grains of these sediments were redeposited with juvenile and non-juvenile basaltic material probably by a combination of back fall, where clasts erupted into the air fell directly back into the structure, and backflow where material was erupted out of the structure, but immediately flowed back in as lahars. This material formed the lower volcaniclastic breccia. A fault plane is identified along the southwestern margin of the subsidence structure, and is believed to continue up the western margin to the northwestern corner. A large dolerite body has intruded along the inferred fault plane on the western margin of the structure, and may be related to the formation of the lower volcaniclastic breccia, either directly through fluidisation of wet sediment during its intrusion, or as a dyke extending upwards from a network of sill-like intrusions below the subsidence structure. Geochemical analysis of the Drakensberg basalt lava flows by Mitchell (1980) and Masokwane (1997) revealed four distinct basalt types; the Moshesh's Ford, the Tafelkop, the Roodehoek, and the Vaalkop basalts. Basalt clasts sampled from the lower volcaniclastic breccia were shown to belong to the Moshesh's Ford basalt type which does not outcrop in situ within the subsidence structure. This implies that the Moshesh's Ford basalts were emplaced prior to the formation of the lower volcaniclastic breccia, and may have acted as a "cap-rock" over the system, allowing pressure from the vaporised fluids, heated by intruding basalt, to build up. The Moshesh's Ford basalt type was erupted prior to the resultant phreatomagmatic events forming the lower volcaniclastic breccia.
- Full Text:
- Authors: Surtees, Grant Bradley
- Date: 2000
- Subjects: Volcanism , Geology -- South Africa -- Eastern Cape -- Brosterlea Volcanic Complex , Geology -- South Africa -- Eastern Cape , Flood basalts , Geology, Structural -- South Africa , Formations (Geology) -- South Africa , Geology, Structural -- Maps , Geological mapping
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4944 , http://hdl.handle.net/10962/d1005556 , Volcanism , Geology -- South Africa -- Eastern Cape -- Brosterlea Volcanic Complex , Geology -- South Africa -- Eastern Cape , Flood basalts , Geology, Structural -- South Africa , Formations (Geology) -- South Africa , Geology, Structural -- Maps , Geological mapping
- Description: Detailed field mapping (Map, Appendix B) has been conducted in and around the boundaries of a 14x18km, volcanic complex 35km northeast of Molteno in the Eastern Cape Province, South Africa. The structure is interpreted as a subsidence structure, and is filled with two volcaniclastic breccias, numerous lava flows, a number of sedimentary facies, and lies on a base of Clarens Formation overlying Elliot Formation rocks. This is an important study because 'widespread, voluminous fields of basaltic breccias are very rare (see Hanson and Elliot, 1996) and this is the first time that this type of volcanic complex and its deposits have been described. Detailed analyses of the two volcaniclastic breccias revealed changes in colour, clast types, clast sizes, and degree of alteration over relatively short distances both vertically and laterally within a single breccia unit. The variation in clast sizes implies a lack of sorting of the breccias. The lower of the two volcaniclastic breccias fills the subsidence structure, and outcrops between the Stormberg sedimentary sequence and the overlying Drakensberg basalts and was produced from phreatomagmatic eruptions signalling the start of the break-up of Gondwanaland in the mid-Jurassic. The upper volcaniclastic breccia is interbedded with the flood basalts and is separated from the lower breccia by up to 100m of lava flows in places, it is finer-grained than the lower volcaniclastic breccia, and it extends over 10km south, and over 100km north from the volcanic complex. The upper breccia is inferred to have been transported from outside the study area, from a source presumably similar to the subsidence structure in the volcanic complex. The pyroclastic material forming the upper breccia was transported to the subsidence structure as a laharic debris flow, based on its poorly sorted, unwelded and matrix-supported appearance. However, both breccias are unlikely to have been derived from epiclastic reworking of lava flows as they contain glass shards which are atypical of those derived from the autoclastic component of lava flows. The breccias are therefore not "secondary" lahars. There is also no evidence of any palaeotopographic highs from which the breccias could have been derived as gravity-driven flows. Based on the occurrence of three, 1m thick lacustrine deposits, localised peperite, fluvial reworking of sandstone and breccia in an outcrop to the south of the subsidence structure, and channel-lags encountered only in the upper units of the Clarens Formation and only within the subsidence structure, the palaeoenvironment inferred for the subsidence structure is one of wet sediment, possibly a shallow lake, in a topographic depression fed by small streams. Magmatic intrusions below the subsidence structure heated the water-laden, partly consolidated Clarens Formation sandstones, causing the circulation of pore fluid which resulted in the precipitation of minerals forming pisoliths in the sandstones. Intruding magma mixed, nonexplosively, with the wet, unconsolidated sediments near the base of the Clarens Formation (at approximately 100m below the surface), forming fluidal peperite by a process of sediment fluidisation where magma replaces wet sediment and cools slowly enough to prevent the magma fracturing brittly. Formation of fluidal peperite may have been a precursor to the development of FCIs (Fuel Coolant Interactions) (Busby-Spera and White, 1987). The breccias may represent the products of FCIs and may be the erupted equivalents of the peperites, suggesting a possible genetic link between the two. The peperites may have given way to FCI eruptions due to a number of factors including the drying out of the sediments and/or an increase in the volume of intruded magma below the subsidence structure which may have resulted in a more explosive interaction between sediment and magma. Phreatic activity fragmented and erupted the Clarens Formation sandstone, and stream flows reworked the angular sandstone fragments, pisoliths and sand grains into channelised deposits. With an increase in magmatic activity below the subsidence structure, phreatic activity became phreatomagmatic. The wet, partly consolidated Clarens Formation, and underlying, fully consolidated Elliot Formation sediments were erupted and fragmented. Clasts and individual grains of these sediments were redeposited with juvenile and non-juvenile basaltic material probably by a combination of back fall, where clasts erupted into the air fell directly back into the structure, and backflow where material was erupted out of the structure, but immediately flowed back in as lahars. This material formed the lower volcaniclastic breccia. A fault plane is identified along the southwestern margin of the subsidence structure, and is believed to continue up the western margin to the northwestern corner. A large dolerite body has intruded along the inferred fault plane on the western margin of the structure, and may be related to the formation of the lower volcaniclastic breccia, either directly through fluidisation of wet sediment during its intrusion, or as a dyke extending upwards from a network of sill-like intrusions below the subsidence structure. Geochemical analysis of the Drakensberg basalt lava flows by Mitchell (1980) and Masokwane (1997) revealed four distinct basalt types; the Moshesh's Ford, the Tafelkop, the Roodehoek, and the Vaalkop basalts. Basalt clasts sampled from the lower volcaniclastic breccia were shown to belong to the Moshesh's Ford basalt type which does not outcrop in situ within the subsidence structure. This implies that the Moshesh's Ford basalts were emplaced prior to the formation of the lower volcaniclastic breccia, and may have acted as a "cap-rock" over the system, allowing pressure from the vaporised fluids, heated by intruding basalt, to build up. The Moshesh's Ford basalt type was erupted prior to the resultant phreatomagmatic events forming the lower volcaniclastic breccia.
- Full Text:
Nyau masquerade performance : shifting the imperial gaze
- Authors: Guhrs, Tamara
- Date: 2000
- Subjects: Masquerades -- Malawi , Masquerades -- Zambia , Malawi -- Religion , Zambia -- Religion , Masks, Chewa , Chewa (African people) -- Rites and ceremonies , Nyanja (African people) -- Rites and ceremonies , Secret societies -- Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2140 , http://hdl.handle.net/10962/d1002372 , Masquerades -- Malawi , Masquerades -- Zambia , Malawi -- Religion , Zambia -- Religion , Masks, Chewa , Chewa (African people) -- Rites and ceremonies , Nyanja (African people) -- Rites and ceremonies , Secret societies -- Africa
- Description: Nyau Masquerades have been studied by missionaries, anthropologists and religious specialists, but have seldom been documented by theatre and performance specialists. This dissertation argues for the acceptance of Ny au performance as a contemporary world theatre form rooted in tradition. Charting the uneasy relationship between the Nyau and those who have sought to record their performances, the author delineates a vivid dramaturgy of this art form. In doing so, the boundaries of what define theatre as it has traditionally been understood in dominant discourses are made more fluid. Nyau performances have been affected by Colonial processes in varied ways. They were banned by the former government of Northern Rhodesia and severely censored by Catholic Mission teachings in the former Nyasaland. Other forms of vilification have been more subtle. Information about performance in Africa has often been collected and arranged in ways which limit the understanding of these genres. Images of Africa which cluster around the notion of the 'Primitive Other' have enabled a representation of Ny au masking as a superstitious and outdated practice with no relevance for contemporary Africa. This work calls for a new examination of the Nyau, through the lens of local discourse as well as contemporary global understandings of performance. Chapter One examines the issue of primitivism and the ways in which Africa has historically been posited as the exotic Other to Europe. Chapter Two examines the Nyau ih terms of specific dramaturgical elements, adjusting previous misconceptions surrounding the theatr~ forms of Chewa and Nyanja people. Chapter Three is devoted to a discussion of space in ritual theatre and Nyau performance, while Chapter Four explores masking and questions of transformation and liminality. In conclusion, it is seen that the use of the mask is a metaphor for the suspension of rigid boundaries separating subject/object, self/other, ritual/theatre, a suspension which needs to take place before an enriched understanding of performance in Africa can be reached.
- Full Text:
- Authors: Guhrs, Tamara
- Date: 2000
- Subjects: Masquerades -- Malawi , Masquerades -- Zambia , Malawi -- Religion , Zambia -- Religion , Masks, Chewa , Chewa (African people) -- Rites and ceremonies , Nyanja (African people) -- Rites and ceremonies , Secret societies -- Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2140 , http://hdl.handle.net/10962/d1002372 , Masquerades -- Malawi , Masquerades -- Zambia , Malawi -- Religion , Zambia -- Religion , Masks, Chewa , Chewa (African people) -- Rites and ceremonies , Nyanja (African people) -- Rites and ceremonies , Secret societies -- Africa
- Description: Nyau Masquerades have been studied by missionaries, anthropologists and religious specialists, but have seldom been documented by theatre and performance specialists. This dissertation argues for the acceptance of Ny au performance as a contemporary world theatre form rooted in tradition. Charting the uneasy relationship between the Nyau and those who have sought to record their performances, the author delineates a vivid dramaturgy of this art form. In doing so, the boundaries of what define theatre as it has traditionally been understood in dominant discourses are made more fluid. Nyau performances have been affected by Colonial processes in varied ways. They were banned by the former government of Northern Rhodesia and severely censored by Catholic Mission teachings in the former Nyasaland. Other forms of vilification have been more subtle. Information about performance in Africa has often been collected and arranged in ways which limit the understanding of these genres. Images of Africa which cluster around the notion of the 'Primitive Other' have enabled a representation of Ny au masking as a superstitious and outdated practice with no relevance for contemporary Africa. This work calls for a new examination of the Nyau, through the lens of local discourse as well as contemporary global understandings of performance. Chapter One examines the issue of primitivism and the ways in which Africa has historically been posited as the exotic Other to Europe. Chapter Two examines the Nyau ih terms of specific dramaturgical elements, adjusting previous misconceptions surrounding the theatr~ forms of Chewa and Nyanja people. Chapter Three is devoted to a discussion of space in ritual theatre and Nyau performance, while Chapter Four explores masking and questions of transformation and liminality. In conclusion, it is seen that the use of the mask is a metaphor for the suspension of rigid boundaries separating subject/object, self/other, ritual/theatre, a suspension which needs to take place before an enriched understanding of performance in Africa can be reached.
- Full Text:
Therapists' constructs of healthy functioning as aspirational goal in transformative psychotherapy
- Authors: Steyn, Reinette
- Date: 2000
- Subjects: Psychotherapy , Mental health -- South Africa , Mental health
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3064 , http://hdl.handle.net/10962/d1002573 , Psychotherapy , Mental health -- South Africa , Mental health
- Description: This dissertation reviews the ways in which psychotherapists working in relatively long-term 'transformational' therapies construct the outcome goals of their interventions. It is generally accepted that a therapist's beliefs about what constitutes mental health will influence the client, and will therefore facilitate a certain outcome accordingly. A problem in a long-term, 'non-directive' therapy is that the eventual outcome is not always visible in the interim development of the client or in the business of individual sessions. Without a clearly defined 'plan' or 'goal' there is a real danger of the intervention having opposite results to what would have been desirable, or no noticeably beneficial results, both of which can be an abuse of the client's investment and trust in the process. The absence of clearly constructed goals makes it difficult to assess efficacy of a therapeutic method used to attain an improved state of mental health that will be lasting, i.e. a positive 'transformation'; it also problematises comparisons across orientations. The identification of explicit goals is of special importance in a developing 'third-world' community like South Africa, where western ('European') concepts of mental health are being offered as an alternative to so-called 'indigenous healing' and where different cultural communities may have different expectations, needs or demands of their members 'in health'. Individual-based therapeutic orientations included in the research were psychoanalysis and psychoanalytic therapies, including object-relational therapies with various emphases and self psychology, as well as transformative types of hypnosis, Gestalt therapy, client-centred therapy and transactional analysis. Twenty of the semi-structured interviews with 52 therapists working in one or more of these areas were selected for construct analysis. Through analysis of the constructs of mental health as aspirational goal that emerged in therapists' talking about their experience of the process and the consequences of therapy observed in their patients, it appeared that there are generalisable constructs across various orientations in the transformative therapies. It is hoped that these constructs may serve as a foundation for further research in the problem areas indicated, but also that therapists working in the field may use this research not only as a basis for self-evaluation, but for adding to the constructs from their own experience, to the further enrichment of the whole field of work.
- Full Text:
- Authors: Steyn, Reinette
- Date: 2000
- Subjects: Psychotherapy , Mental health -- South Africa , Mental health
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3064 , http://hdl.handle.net/10962/d1002573 , Psychotherapy , Mental health -- South Africa , Mental health
- Description: This dissertation reviews the ways in which psychotherapists working in relatively long-term 'transformational' therapies construct the outcome goals of their interventions. It is generally accepted that a therapist's beliefs about what constitutes mental health will influence the client, and will therefore facilitate a certain outcome accordingly. A problem in a long-term, 'non-directive' therapy is that the eventual outcome is not always visible in the interim development of the client or in the business of individual sessions. Without a clearly defined 'plan' or 'goal' there is a real danger of the intervention having opposite results to what would have been desirable, or no noticeably beneficial results, both of which can be an abuse of the client's investment and trust in the process. The absence of clearly constructed goals makes it difficult to assess efficacy of a therapeutic method used to attain an improved state of mental health that will be lasting, i.e. a positive 'transformation'; it also problematises comparisons across orientations. The identification of explicit goals is of special importance in a developing 'third-world' community like South Africa, where western ('European') concepts of mental health are being offered as an alternative to so-called 'indigenous healing' and where different cultural communities may have different expectations, needs or demands of their members 'in health'. Individual-based therapeutic orientations included in the research were psychoanalysis and psychoanalytic therapies, including object-relational therapies with various emphases and self psychology, as well as transformative types of hypnosis, Gestalt therapy, client-centred therapy and transactional analysis. Twenty of the semi-structured interviews with 52 therapists working in one or more of these areas were selected for construct analysis. Through analysis of the constructs of mental health as aspirational goal that emerged in therapists' talking about their experience of the process and the consequences of therapy observed in their patients, it appeared that there are generalisable constructs across various orientations in the transformative therapies. It is hoped that these constructs may serve as a foundation for further research in the problem areas indicated, but also that therapists working in the field may use this research not only as a basis for self-evaluation, but for adding to the constructs from their own experience, to the further enrichment of the whole field of work.
- Full Text:
Aspects of the ecology and reproductive biology of the limpet, Helcion pruinosus (Gastropoda : prosobranchia)
- Authors: Henninger, Tony Oskar
- Date: 2000
- Subjects: Prosobranchia , Limpets -- Reproduction , Limpets -- Ecology , Prosobranchia -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5641 , http://hdl.handle.net/10962/d1005323 , Prosobranchia , Limpets -- Reproduction , Limpets -- Ecology , Prosobranchia -- Ecology
- Description: Helcion pruinosus, the rayed limpet, is found in the midshore region of the intertidal zone, (i.e. the Balanoid zone) of rocky shores, from Saldanha Bay to Sodwana Bay along the coast of South Africa. At Gonubie (32°57'S/25°01'E) this species of limpet was found under boulders, (when not feeding), and could reach average densities of 85/ m². The limpets prefer smooth boulders, avoiding those encrusted by coralline algae or boulders with a rough texture. There was no habitat segregation between adult and juvenile H. pruinosus, i.e. there was no sign of up-shore migration by larger individuals. Males out-numbered females by, on average 1.4 : 1, which was a similar sex ratio to that of the congeneric species, H. pectunculus (Gray, 996). Unlike H. pectunculus, there were no differences in shell lengths between males and females (p = 0.946 at Gonubie, south-east coast and p = 0.961 at Kommetjie, south-west coast; t-test). Shell height could also not be used as a criterion to differentiate between the sexes. The average maximum shell length of H. pruinosus at Gonubie and Kommetjie was 25 mm, but the maximum shell lengths found were 30 mm, (one individual in each case), on both the southeast coast and west coast. Growth occurred most rapidly in the first year of life, with individuals reaching 15 mm after 1 year. In the second year limpet growth slowed to only 7 mm. Sexual maturity was reached at a shell length of between 11 to 14 mm (at an age of 8 months to 1 year). The life-span of H. pruinosus was determined at 2.55 years on the south-east coast and 2.9 years on the south-west coast. Micro-growth bands were produced tidally. Growth occurred allometrically, i.e. shell length increased at a faster rate than shell height. The limpets foraged during low tide, at night, presumably feeding on epilithic algae on the boulders. A second smaller peak of limpet activity was often recorded during the day, when low tide coincided with dawn). More limpets (up to ten times more) were active at spring tides compared to neap tides. Limpet activity was greatest during the spring tides of autumn. During all seasons limpet activity peaked 30 minutes before low water, after which numbers decreased rapidly. All limpets had retreated beneath the boulders before being covered by the flooding tide. It was concluded that the limpets were responding to both endogenous and exogenous cues, but the actual stimulus for retreat could not be determined. The limpets did not return to a fixed scar nor did they return rigidly to a home site. H. pruinosus was found to be gonochoristic. Sexes could be separated, on dissection, according to the colour of their gonads (males had white gonads, whilst that of the females was olive-green). Gonads were present throughout the year in most individuals, i.e. totally spent animals were never observed. Reproductive seasonality was similar in west coast and south-east coast animals. The gonad indices of the west coast limpets were higher, (maximum of 35%), compared to that on the southeast coast, (25%). The animals were probably trickle spawners, with some individuals liberating gametes throughout the year. There was however synchrony in gametogenesis between male and female limpets on both the west coast and south-east coast lines. Gonad indices peaked in the summer months (October to December) with a second minor peak in April/May. These peaks occurred before the release of the gametes in spawning events. The gonad index was lowest in winter, (July). The ovaries were full of mature eggs (oocytes having a diameter of 200 to 250 ~) prior to spawning. The acinal wall thickness had been decreasing prior to spawning. After spawning there was an increase in previtellogenic eggs « 100 μm) in females, and an increase in the acinal wall thickness to indicate spermatogenesis. The two populations are subjected to different environmental conditions and the actual cue for stimulating the release of gametes could not be determined. Finally, a table of differences between H pruinosus and its sister species, H pectunculus was created to show the life-style of H pruinosus.
- Full Text:
- Authors: Henninger, Tony Oskar
- Date: 2000
- Subjects: Prosobranchia , Limpets -- Reproduction , Limpets -- Ecology , Prosobranchia -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5641 , http://hdl.handle.net/10962/d1005323 , Prosobranchia , Limpets -- Reproduction , Limpets -- Ecology , Prosobranchia -- Ecology
- Description: Helcion pruinosus, the rayed limpet, is found in the midshore region of the intertidal zone, (i.e. the Balanoid zone) of rocky shores, from Saldanha Bay to Sodwana Bay along the coast of South Africa. At Gonubie (32°57'S/25°01'E) this species of limpet was found under boulders, (when not feeding), and could reach average densities of 85/ m². The limpets prefer smooth boulders, avoiding those encrusted by coralline algae or boulders with a rough texture. There was no habitat segregation between adult and juvenile H. pruinosus, i.e. there was no sign of up-shore migration by larger individuals. Males out-numbered females by, on average 1.4 : 1, which was a similar sex ratio to that of the congeneric species, H. pectunculus (Gray, 996). Unlike H. pectunculus, there were no differences in shell lengths between males and females (p = 0.946 at Gonubie, south-east coast and p = 0.961 at Kommetjie, south-west coast; t-test). Shell height could also not be used as a criterion to differentiate between the sexes. The average maximum shell length of H. pruinosus at Gonubie and Kommetjie was 25 mm, but the maximum shell lengths found were 30 mm, (one individual in each case), on both the southeast coast and west coast. Growth occurred most rapidly in the first year of life, with individuals reaching 15 mm after 1 year. In the second year limpet growth slowed to only 7 mm. Sexual maturity was reached at a shell length of between 11 to 14 mm (at an age of 8 months to 1 year). The life-span of H. pruinosus was determined at 2.55 years on the south-east coast and 2.9 years on the south-west coast. Micro-growth bands were produced tidally. Growth occurred allometrically, i.e. shell length increased at a faster rate than shell height. The limpets foraged during low tide, at night, presumably feeding on epilithic algae on the boulders. A second smaller peak of limpet activity was often recorded during the day, when low tide coincided with dawn). More limpets (up to ten times more) were active at spring tides compared to neap tides. Limpet activity was greatest during the spring tides of autumn. During all seasons limpet activity peaked 30 minutes before low water, after which numbers decreased rapidly. All limpets had retreated beneath the boulders before being covered by the flooding tide. It was concluded that the limpets were responding to both endogenous and exogenous cues, but the actual stimulus for retreat could not be determined. The limpets did not return to a fixed scar nor did they return rigidly to a home site. H. pruinosus was found to be gonochoristic. Sexes could be separated, on dissection, according to the colour of their gonads (males had white gonads, whilst that of the females was olive-green). Gonads were present throughout the year in most individuals, i.e. totally spent animals were never observed. Reproductive seasonality was similar in west coast and south-east coast animals. The gonad indices of the west coast limpets were higher, (maximum of 35%), compared to that on the southeast coast, (25%). The animals were probably trickle spawners, with some individuals liberating gametes throughout the year. There was however synchrony in gametogenesis between male and female limpets on both the west coast and south-east coast lines. Gonad indices peaked in the summer months (October to December) with a second minor peak in April/May. These peaks occurred before the release of the gametes in spawning events. The gonad index was lowest in winter, (July). The ovaries were full of mature eggs (oocytes having a diameter of 200 to 250 ~) prior to spawning. The acinal wall thickness had been decreasing prior to spawning. After spawning there was an increase in previtellogenic eggs « 100 μm) in females, and an increase in the acinal wall thickness to indicate spermatogenesis. The two populations are subjected to different environmental conditions and the actual cue for stimulating the release of gametes could not be determined. Finally, a table of differences between H pruinosus and its sister species, H pectunculus was created to show the life-style of H pruinosus.
- Full Text:
Female school principals=perceptions of leadership in a male dominated education environment
- Authors: Mwingi, Mweru P
- Date: 2000
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/326 , vital:19948
- Description: Many well-known studies on leadership have ignored the perspective of women yet bear an emphasis on the importance of portraying leadership in its entirety. This would mean that all leadership perspectives are included and that leaders are allowed to speak for themselves and about themselves. It is this connection I have sought to establish how women perceive leadership by relating the experiences of four women in school principalship. I have used a factual questionnaire to establish the background of each one but, it is the in-depth interviews that yield the leadership perceptions. Borrowing from phenomenological procedures, the leadership experiences are related as Natural Meaning Units (NMUS) whereby all prior knowledge and possible bias are bracketed out. Reinforced by their journal entries, it is only the voice of the women that is heard. My study reinforces the observation of researchers and feminist scholars that women leaders are not only marginalised but also viewed from a perspective that is not their own. From the study, however, the one element about leadership that emerges as unique is the functioning of transformational leadership elements among women leaders in educational set-ups that are inherently traditional, bureaucratic and hierarchical. This is significant because there is an indication that women leaders are inclined to transformational leadership because it favours their feminine qualities. There is also evidence that school principals can embrace leadership diversity and finally, that leadership and the structures of leadership operation are not developed from without but from within the person of the leader and this is an incorporation of their vision and beliefs. In the context of South Africa, this study should be of potential significance because of the change that is taking place in the development and training of school principals.
- Full Text:
- Authors: Mwingi, Mweru P
- Date: 2000
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/326 , vital:19948
- Description: Many well-known studies on leadership have ignored the perspective of women yet bear an emphasis on the importance of portraying leadership in its entirety. This would mean that all leadership perspectives are included and that leaders are allowed to speak for themselves and about themselves. It is this connection I have sought to establish how women perceive leadership by relating the experiences of four women in school principalship. I have used a factual questionnaire to establish the background of each one but, it is the in-depth interviews that yield the leadership perceptions. Borrowing from phenomenological procedures, the leadership experiences are related as Natural Meaning Units (NMUS) whereby all prior knowledge and possible bias are bracketed out. Reinforced by their journal entries, it is only the voice of the women that is heard. My study reinforces the observation of researchers and feminist scholars that women leaders are not only marginalised but also viewed from a perspective that is not their own. From the study, however, the one element about leadership that emerges as unique is the functioning of transformational leadership elements among women leaders in educational set-ups that are inherently traditional, bureaucratic and hierarchical. This is significant because there is an indication that women leaders are inclined to transformational leadership because it favours their feminine qualities. There is also evidence that school principals can embrace leadership diversity and finally, that leadership and the structures of leadership operation are not developed from without but from within the person of the leader and this is an incorporation of their vision and beliefs. In the context of South Africa, this study should be of potential significance because of the change that is taking place in the development and training of school principals.
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Road culture : an investigation of the road as a means of mental and physical exploration
- Authors: Meistre, Brent Arthur
- Date: 2000
- Subjects: Roads in art , Travel in art , Travel -- Psychological aspects , Travelers -- Psychology
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2414 , http://hdl.handle.net/10962/d1002210 , Roads in art , Travel in art , Travel -- Psychological aspects , Travelers -- Psychology
- Description: Chapter one considers various manifestations of the concept of ‘journey’ and how they have changed over history. The Odyssean journey that the hero undertakes to reach a point of self-realisation is investigated. This leads to a other discussion of types of journeys such as pilgrimages, as well as ‘wandering’. These are contrasted with the twentieth century perceptions of journey. Questions of travel are then dealt with: how the nature of the traveller's path has changed over the centuries, various points of travel and gender, and how in the last century solitary travel has been transformed into mass tourism. The second chapter deals specifically with the motorcar, the mobility it enables and how it has led to the rise of a roadside culture. Different factors that influenced the rise of the motorcar are looked at. The motorcar as a cell and eroticism and the car are also investigated. The twentieth century city, it's restructuring, as well as the highway systems is discussed. In Chapter Three, the sense of freedom that the motorcar created is considered in particular reference to escape, aimlessness, and road weariness, as well as the landscape as a symbol of freedom. This leads to a discussion on the notion of speed, the sense of power and the romanticisation of death in car crashes. Chapter Four investigates masculinity and the road. The frontier as a place in the psyche of the male is also dealt with. The road as a means of testing and regaining masculinity in the mid-twentieth century is considered. Issues of the male domination of the land and the feminine are discussed, with the chapter ending with a brief examination of the woman as traveller. Lastly the masters’ submission exhibition, entitled RODE is discussed with direct reference to the theories investigated in the previous chapters. Individual works as well as the methodology are looked at closely.
- Full Text:
- Authors: Meistre, Brent Arthur
- Date: 2000
- Subjects: Roads in art , Travel in art , Travel -- Psychological aspects , Travelers -- Psychology
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2414 , http://hdl.handle.net/10962/d1002210 , Roads in art , Travel in art , Travel -- Psychological aspects , Travelers -- Psychology
- Description: Chapter one considers various manifestations of the concept of ‘journey’ and how they have changed over history. The Odyssean journey that the hero undertakes to reach a point of self-realisation is investigated. This leads to a other discussion of types of journeys such as pilgrimages, as well as ‘wandering’. These are contrasted with the twentieth century perceptions of journey. Questions of travel are then dealt with: how the nature of the traveller's path has changed over the centuries, various points of travel and gender, and how in the last century solitary travel has been transformed into mass tourism. The second chapter deals specifically with the motorcar, the mobility it enables and how it has led to the rise of a roadside culture. Different factors that influenced the rise of the motorcar are looked at. The motorcar as a cell and eroticism and the car are also investigated. The twentieth century city, it's restructuring, as well as the highway systems is discussed. In Chapter Three, the sense of freedom that the motorcar created is considered in particular reference to escape, aimlessness, and road weariness, as well as the landscape as a symbol of freedom. This leads to a discussion on the notion of speed, the sense of power and the romanticisation of death in car crashes. Chapter Four investigates masculinity and the road. The frontier as a place in the psyche of the male is also dealt with. The road as a means of testing and regaining masculinity in the mid-twentieth century is considered. Issues of the male domination of the land and the feminine are discussed, with the chapter ending with a brief examination of the woman as traveller. Lastly the masters’ submission exhibition, entitled RODE is discussed with direct reference to the theories investigated in the previous chapters. Individual works as well as the methodology are looked at closely.
- Full Text:
The nature and control of organic compounds in soda ash evaporate production
- Masemola, Patricia Mmoniemang
- Authors: Masemola, Patricia Mmoniemang
- Date: 2000
- Subjects: Organic compounds , Biotic communities , Sua Pan Soda Ash Project -- Botswana
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3902 , http://hdl.handle.net/10962/d1003961 , Organic compounds , Biotic communities , Sua Pan Soda Ash Project -- Botswana
- Description: Solar evaporite systems are man-managed ecosystems which are highly vulnerable to biological,physical and chemical disturbances. The problems encountered in such systems are in many cases found to be associated with the microbial ecology and the design of the system. This project focussed on investigating the nature of organic compounds contaminating soda ash produced at a solar evaporite production system located at Sua Pan in Botswana. Several years after the plant was commissioned, problems, including accumulation of total organic carbon (TOC) and discolouration of the soda ash product were encountered. The salt produced also retained high moisture content and was coloured pink. These phenomena impacted severely on the economic performance of the enterprise. This study was aimed at determining the origin and fate of these organic compounds within the system in order to elucidate the nature of the problem and also to conceptualise a remediation strategy suitable to reducing its impact. This was achieved by analysis of both dialysed and solvent extracts of the influent brine (well-brine), brine in the ponds (T-brine) and the bicarbonate filter cake. Although complete identification of the organic compounds isolated was not undertaken in this study, spectroscopic analysis of compounds isolated, by UV, IR, NMR and MS, strongly indicated that fulvic acids, a component of the influent well-brine organics, contribute to the organic contamination of the final product. Part of this component, however, is degraded during the ponding process. It was shown that an extracellular polysaccharide (EPS) produced by Dunaliella. spp., which proliferates in the evaporation ponds, contributes in a major way to the accumulation of TOC in the system. This was demonstrated by relating the sugar profile of carbohydrates isolated from the pond brine and final product, being arabinose, xylose, 2-o-methyl hexose, mannose, glucose and galactose. Studies reported show that EPS production was enhanced when algal cultures were exposed to stress conditions of high illumination, increasing salinity and temperature, and nitrogen limitation. Studies undertaken for the development of a remediation process for this system have shown that nutrient stripping and bacterial systems could be applied to deal with the dissolved TOC fraction, whereas adsorption systems could deal with the particulate fractions. Algal systems showed most potential for the removal of nutrients in the influent well-brine compared to chemical processes.Complete removal of ammonium and phosphorus removal efficiencies of pproximately 50% were achieved in an unoptimised pilot-scale Dunaliella-based HRAP. While similar effects were demonstrated for chemical processes, some economic constraints were noted. The potential of halophilic bacterial systems for the degradation of organic compounds in brine was also demonstrated. The limitations on the performance of such systems, associated with the low metabolic diversity, and poor immobilisation of physico-chemical processes were found to have a very low impact on the dissolved TOC fraction of the brine, the removal of the particulate material was found to result in a 35% TOC reduction in the final soda ash product and the production of a white final product.halobacteria, however, were noted. Although physico-chemical processes were found to have a very low impact on the dissolved TOC fraction of the brine, the removal of the particulate material was found to result in a 35% TOC reduction in the final soda ash product and the production of a white final product. Apart from a description of the microbial ecology of the ponds and the identification of major contributions to the TOC of the final product, a number of remediation strategies were evaluated and are described. These include chemical and biological stripping of nutrients sustaining microbial TOC production in the ponds, and also biological and physico-chemical processes for their removal once formed. Future studies to undertake the further development of these proposals has been described
- Full Text:
- Authors: Masemola, Patricia Mmoniemang
- Date: 2000
- Subjects: Organic compounds , Biotic communities , Sua Pan Soda Ash Project -- Botswana
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3902 , http://hdl.handle.net/10962/d1003961 , Organic compounds , Biotic communities , Sua Pan Soda Ash Project -- Botswana
- Description: Solar evaporite systems are man-managed ecosystems which are highly vulnerable to biological,physical and chemical disturbances. The problems encountered in such systems are in many cases found to be associated with the microbial ecology and the design of the system. This project focussed on investigating the nature of organic compounds contaminating soda ash produced at a solar evaporite production system located at Sua Pan in Botswana. Several years after the plant was commissioned, problems, including accumulation of total organic carbon (TOC) and discolouration of the soda ash product were encountered. The salt produced also retained high moisture content and was coloured pink. These phenomena impacted severely on the economic performance of the enterprise. This study was aimed at determining the origin and fate of these organic compounds within the system in order to elucidate the nature of the problem and also to conceptualise a remediation strategy suitable to reducing its impact. This was achieved by analysis of both dialysed and solvent extracts of the influent brine (well-brine), brine in the ponds (T-brine) and the bicarbonate filter cake. Although complete identification of the organic compounds isolated was not undertaken in this study, spectroscopic analysis of compounds isolated, by UV, IR, NMR and MS, strongly indicated that fulvic acids, a component of the influent well-brine organics, contribute to the organic contamination of the final product. Part of this component, however, is degraded during the ponding process. It was shown that an extracellular polysaccharide (EPS) produced by Dunaliella. spp., which proliferates in the evaporation ponds, contributes in a major way to the accumulation of TOC in the system. This was demonstrated by relating the sugar profile of carbohydrates isolated from the pond brine and final product, being arabinose, xylose, 2-o-methyl hexose, mannose, glucose and galactose. Studies reported show that EPS production was enhanced when algal cultures were exposed to stress conditions of high illumination, increasing salinity and temperature, and nitrogen limitation. Studies undertaken for the development of a remediation process for this system have shown that nutrient stripping and bacterial systems could be applied to deal with the dissolved TOC fraction, whereas adsorption systems could deal with the particulate fractions. Algal systems showed most potential for the removal of nutrients in the influent well-brine compared to chemical processes.Complete removal of ammonium and phosphorus removal efficiencies of pproximately 50% were achieved in an unoptimised pilot-scale Dunaliella-based HRAP. While similar effects were demonstrated for chemical processes, some economic constraints were noted. The potential of halophilic bacterial systems for the degradation of organic compounds in brine was also demonstrated. The limitations on the performance of such systems, associated with the low metabolic diversity, and poor immobilisation of physico-chemical processes were found to have a very low impact on the dissolved TOC fraction of the brine, the removal of the particulate material was found to result in a 35% TOC reduction in the final soda ash product and the production of a white final product.halobacteria, however, were noted. Although physico-chemical processes were found to have a very low impact on the dissolved TOC fraction of the brine, the removal of the particulate material was found to result in a 35% TOC reduction in the final soda ash product and the production of a white final product. Apart from a description of the microbial ecology of the ponds and the identification of major contributions to the TOC of the final product, a number of remediation strategies were evaluated and are described. These include chemical and biological stripping of nutrients sustaining microbial TOC production in the ponds, and also biological and physico-chemical processes for their removal once formed. Future studies to undertake the further development of these proposals has been described
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Towards an understanding of the role of commercialisation in programming at the Malawi Broadcasting Corporation from 1995 to 1998 : a case study
- Chikunkhuzeni, Francis Chim'ndomo
- Authors: Chikunkhuzeni, Francis Chim'ndomo
- Date: 2000
- Subjects: Malawi Broadcasting Corporation , Broadcasting -- Malawi , Public broadcasting -- Malawi , Broadcasting policy -- Malawi , Broadcast advertising -- Malawi
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3422 , http://hdl.handle.net/10962/d1002875 , Malawi Broadcasting Corporation , Broadcasting -- Malawi , Public broadcasting -- Malawi , Broadcasting policy -- Malawi , Broadcast advertising -- Malawi
- Description: Competition in many market-driven media systems in advanced industrial countries can sometimes compromise traditional public service broadcast values such as programming for diversity, citizenship, minority interests and national identity. This study investigates the presence and effects of commercial-logic in a state-owned broadcaster in a developing country: the Malawi Broadcasting Corporation. Using indepth interviews and analysis of records on finance and programme schedules, the study finds overwhelming indicators of the presence of commercial logic, not driven by competition, but a commitment to provide a public service under deteriorating financial conditions. Distinguishing between the impacts of advertising and sponsorship markets on media output, the study finds contradictory effects of commercialisation. Some effects confirm some of the adverse effects of commercialisation such as heavy sponsorinfluence on programme content, self-censorship among programme producers who avoid injuring sponsors and producers paying more attention to sponsored programmes at the expense ofthe quality of some non-sponsored public service programmes. However, effects are not always contrary to public service broadcasting but may Indeed reinforce such broadcasting. Commercialisation in some instances has led to the sustenance of a range of non-sponsored public service programmes including programmes to promote culture and civic rights. In general, this study highlights the need to focus on what is realistically possible within the dynamics of the Malawi Society as a precondition for a proactive and elaborate strategy for commercialisation ofthe country's public broadcaster.
- Full Text:
- Authors: Chikunkhuzeni, Francis Chim'ndomo
- Date: 2000
- Subjects: Malawi Broadcasting Corporation , Broadcasting -- Malawi , Public broadcasting -- Malawi , Broadcasting policy -- Malawi , Broadcast advertising -- Malawi
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3422 , http://hdl.handle.net/10962/d1002875 , Malawi Broadcasting Corporation , Broadcasting -- Malawi , Public broadcasting -- Malawi , Broadcasting policy -- Malawi , Broadcast advertising -- Malawi
- Description: Competition in many market-driven media systems in advanced industrial countries can sometimes compromise traditional public service broadcast values such as programming for diversity, citizenship, minority interests and national identity. This study investigates the presence and effects of commercial-logic in a state-owned broadcaster in a developing country: the Malawi Broadcasting Corporation. Using indepth interviews and analysis of records on finance and programme schedules, the study finds overwhelming indicators of the presence of commercial logic, not driven by competition, but a commitment to provide a public service under deteriorating financial conditions. Distinguishing between the impacts of advertising and sponsorship markets on media output, the study finds contradictory effects of commercialisation. Some effects confirm some of the adverse effects of commercialisation such as heavy sponsorinfluence on programme content, self-censorship among programme producers who avoid injuring sponsors and producers paying more attention to sponsored programmes at the expense ofthe quality of some non-sponsored public service programmes. However, effects are not always contrary to public service broadcasting but may Indeed reinforce such broadcasting. Commercialisation in some instances has led to the sustenance of a range of non-sponsored public service programmes including programmes to promote culture and civic rights. In general, this study highlights the need to focus on what is realistically possible within the dynamics of the Malawi Society as a precondition for a proactive and elaborate strategy for commercialisation ofthe country's public broadcaster.
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An investigation of male and female cognitive ability on the WAIS-III
- Authors: Muirhead, Joanne
- Date: 2000
- Subjects: Wechsler Adult Intelligence Scale , Sex differences (Psychology) , Intelligence tests -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3028 , http://hdl.handle.net/10962/d1002537 , Wechsler Adult Intelligence Scale , Sex differences (Psychology) , Intelligence tests -- South Africa
- Description: This study, which formed part of a larger research project, investigated the effect of gender on test performance on the Wechsler Adult Intelligence Scale - Third Edition (WAIS-III). The WAIS-III was administered to a sample of 68 participants in the Eastern Cape following the initiative of the Human Sciences Research Council to standardise the WAIS-III for a South African population. The participants, aged 19 to 30, were stratified according to language of origin (African or English First Language), educational attainment (matriculant or graduate), quality of education (Department of Education and Training or private/"Model C" school) and gender. Analyses of variance and two sample t tests were used to compare male and female test performance. For the total sample, no significant difference between males and females on Verbal, Performance and Full Scale IQ were found. On the factor indices, females scored marginally higher than males on Processing Speed at a level which was approaching significance (p = 0.105), but no significant differences were found. On subtest performance, females significantly outperformed males on Digit Symbol (p = 0.020). Differences which were approaching significance were found on Information (p = 0.133) in favour of males, and on Matrix Reasoning (p = 0.092) in favour of females. For subgroups of the total sample, the most significant differences in test performance were found for the African First Language private/"Model C" school cohort in favour of females. Thus the overriding implication that emerged from this research was that on this relatively highly educated sample, no significant gender differences in cognitive ability were apparent.
- Full Text:
- Authors: Muirhead, Joanne
- Date: 2000
- Subjects: Wechsler Adult Intelligence Scale , Sex differences (Psychology) , Intelligence tests -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3028 , http://hdl.handle.net/10962/d1002537 , Wechsler Adult Intelligence Scale , Sex differences (Psychology) , Intelligence tests -- South Africa
- Description: This study, which formed part of a larger research project, investigated the effect of gender on test performance on the Wechsler Adult Intelligence Scale - Third Edition (WAIS-III). The WAIS-III was administered to a sample of 68 participants in the Eastern Cape following the initiative of the Human Sciences Research Council to standardise the WAIS-III for a South African population. The participants, aged 19 to 30, were stratified according to language of origin (African or English First Language), educational attainment (matriculant or graduate), quality of education (Department of Education and Training or private/"Model C" school) and gender. Analyses of variance and two sample t tests were used to compare male and female test performance. For the total sample, no significant difference between males and females on Verbal, Performance and Full Scale IQ were found. On the factor indices, females scored marginally higher than males on Processing Speed at a level which was approaching significance (p = 0.105), but no significant differences were found. On subtest performance, females significantly outperformed males on Digit Symbol (p = 0.020). Differences which were approaching significance were found on Information (p = 0.133) in favour of males, and on Matrix Reasoning (p = 0.092) in favour of females. For subgroups of the total sample, the most significant differences in test performance were found for the African First Language private/"Model C" school cohort in favour of females. Thus the overriding implication that emerged from this research was that on this relatively highly educated sample, no significant gender differences in cognitive ability were apparent.
- Full Text:
Rural students' local knowledge of learning in formal and informal contexts
- Authors: Visser, Alvin-Jon
- Date: 2000
- Subjects: Non-formal education -- South Africa , Education and state -- South Africa , Rural children -- Education -- South Africa , Black people -- Education -- South Africa , Community and school -- South Africa , Education, Rural -- Social Aspects -- South Africa , Rural schools -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3079 , http://hdl.handle.net/10962/d1002588 , Non-formal education -- South Africa , Education and state -- South Africa , Rural children -- Education -- South Africa , Black people -- Education -- South Africa , Community and school -- South Africa , Education, Rural -- Social Aspects -- South Africa , Rural schools -- South Africa
- Description: The general aim of this thesis is to illuminate the process of learning as it occurs in formal and informal contexts. The study focuses on South African scholars attending school in rural areas where the contrast between learning in formal and informal learning contexts is more pronounced than that in urban areas. The research draws on rural scholars' local knowledge of formal and informal learning contexts in order to gain a rich insight into how cognition is situated in different learning contexts. This is accomplished through investigating the structure of the respective learning tasks, the mediators involved, the task objectives and the means for achieving these objectives in the different learning contexts. The thesis draws on a socio-cultural approach to the study of cognitive development to probe the activity of learning in a formal and informal learning context. Through the use of a context sensitive methodological methods especially Participatory Rural Appraisal (PRA) tools and techniques, it was possible to illuminate tacit local knowledge structures and to get participants to actively explicate their understandings related to learning in different contexts The research results illustrate the assertion that the activity of learning is fundamentally situated in the learning context from which it arises. Learning is framed by the community of practice which structures affordances for situated learning, through mediation, within zones of proximal development. Learning in a formal context such as the school is often abstract, rule-based, standardised and theory related. Learners also find it difficult to reflect on the learning tasks and the mediational means used in a formal learning context. In contrast, the learning which takes place in an informal setting is often practical, individualised, flexible and environment based. This learning is structured around everyday activities and is dynamically defined and supported. In a situation where a learner is exposed to dislocated learning contexts, the essential goal of educational initiatives is to bridge the gap between the two. This can be achieved through mediators creating effective zones of proximal development which facilitate the individuals adaptation between learning contexts. Exposing rural scholars' local knowledge of learning in formal and informal contexts allows for a fuller understanding of the cognitive development structured within formal and informal communities of practice. It is this understanding that is necessary to address the situation where learning contexts, drawing on different knowledge bases find ways of thinking, prove challenging and/or conflicting to the scholar.
- Full Text:
- Authors: Visser, Alvin-Jon
- Date: 2000
- Subjects: Non-formal education -- South Africa , Education and state -- South Africa , Rural children -- Education -- South Africa , Black people -- Education -- South Africa , Community and school -- South Africa , Education, Rural -- Social Aspects -- South Africa , Rural schools -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3079 , http://hdl.handle.net/10962/d1002588 , Non-formal education -- South Africa , Education and state -- South Africa , Rural children -- Education -- South Africa , Black people -- Education -- South Africa , Community and school -- South Africa , Education, Rural -- Social Aspects -- South Africa , Rural schools -- South Africa
- Description: The general aim of this thesis is to illuminate the process of learning as it occurs in formal and informal contexts. The study focuses on South African scholars attending school in rural areas where the contrast between learning in formal and informal learning contexts is more pronounced than that in urban areas. The research draws on rural scholars' local knowledge of formal and informal learning contexts in order to gain a rich insight into how cognition is situated in different learning contexts. This is accomplished through investigating the structure of the respective learning tasks, the mediators involved, the task objectives and the means for achieving these objectives in the different learning contexts. The thesis draws on a socio-cultural approach to the study of cognitive development to probe the activity of learning in a formal and informal learning context. Through the use of a context sensitive methodological methods especially Participatory Rural Appraisal (PRA) tools and techniques, it was possible to illuminate tacit local knowledge structures and to get participants to actively explicate their understandings related to learning in different contexts The research results illustrate the assertion that the activity of learning is fundamentally situated in the learning context from which it arises. Learning is framed by the community of practice which structures affordances for situated learning, through mediation, within zones of proximal development. Learning in a formal context such as the school is often abstract, rule-based, standardised and theory related. Learners also find it difficult to reflect on the learning tasks and the mediational means used in a formal learning context. In contrast, the learning which takes place in an informal setting is often practical, individualised, flexible and environment based. This learning is structured around everyday activities and is dynamically defined and supported. In a situation where a learner is exposed to dislocated learning contexts, the essential goal of educational initiatives is to bridge the gap between the two. This can be achieved through mediators creating effective zones of proximal development which facilitate the individuals adaptation between learning contexts. Exposing rural scholars' local knowledge of learning in formal and informal contexts allows for a fuller understanding of the cognitive development structured within formal and informal communities of practice. It is this understanding that is necessary to address the situation where learning contexts, drawing on different knowledge bases find ways of thinking, prove challenging and/or conflicting to the scholar.
- Full Text:
Cumulative mild head injury in contact sport: a comparison of the cognitive profiles of rugby players and non-contact sport controls with normative data
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
The use of indigenous macroinvertebrates and Daphnia pulex in acute toxicity testing
- Authors: Everitt, Victoria Jane
- Date: 2000
- Subjects: Water -- Pollution -- Toxicology , Toxicity testing , Daphnia pulex
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5795 , http://hdl.handle.net/10962/d1005483
- Description: Aquatic toxicology has been identified as a valuable tool in the identification and management of chemical pollution in aquatic ecosystems. Standardised methodologies for acute aquatic bioassays have been adopted from international agencies. As a result of these standard methods, the use of laboratory cultured organisms for toxicity testing has been more popular than that of indigenous field-caught organisms. Included in these adopted methods are those for the cultured crustacean Daphnia pUlex. D.pulex is adapted to living in standing water and the suitability of this species to determine toxic effects for South African riverine environments, which are largely flowing, has been questioned. Thus this thesis is a case-study ofthe use of D.pulex and indigenous site-specific macroinvertebrates as toxicity test organisms for setting acute water quality guidelines to protect aquatic ecosystems. The study highlights site-specific problems such as reference sites and organism identification. The acute tolerance of selected indigenous invertebrates was compared to that of D. pulex, using both a single-substance reference toxicant (zinc) and selected whole efiluents. The significance of source population and culture age as a potential source of biological variability between D.pulex cultures was also investigated. D.pulex cultures have been initiated in South Africa from females collected from a number of different local populations; also it is assumed that no genetic change (due to mutation) occurs within a D.pulex culture over time. In order to establish if source population and culture age are a source of biological variability between D.pulex experiments, the acute tolerJuce to zinc of two different D.pulex populations and three different generations within a population were compared. Due to experimental variability results were inconclusive, and differences in tolerance as a result of population difference or culture age could not be determined with confidence. The acute tolerance of D.pulex to a single reference chemical (zinc) and selected whole efiluents was compared to that of selected indigenous invertebrates. Acute 48 h D.pulex zinc tolerance (LC50 range: 0.22 - 0.60 mg/l Zn) was found to be more sensitive than acute 96 h tolerances shown by mayfly species A.fconurus peringueyi (Heptageniidae) (LC50: 17.42 mg/l Zn), Euthrauluselegans (Leptophlebiidae) (LC50: 0.98 mg/IZn), Ba~tidae (LC50: 0.94mg/IZn) and shrimp, Caradina nilotica (Atyidae) (LC50: 3.17 mg/l Zn). This result suggests that guidelines for zinc set using D.pulex will protect the selected indigenous invertebrates. Selected whole eftluents were not acutely toxic to either D.pulex or selected indigenous invertebrates. These experiments were used as a case study for method development regarding the comparative use of D.pulex and indigenous invertebrates in acute whole eftluent toxicity testing. Finally, it is recommended that a suite of indigenous organisms (e.g. macroinvertebrates, fish and algae), as well as laboratory cultured D.pulex, be used in the initial setting of guidelines and that D.pulex be used for routine compliance monitoring. It is futher recommended that a suite of available monitoring methods, such as chemical and biomonitoring methodologies, be used in conjuction with toxicity testing in water quality management.
- Full Text:
- Authors: Everitt, Victoria Jane
- Date: 2000
- Subjects: Water -- Pollution -- Toxicology , Toxicity testing , Daphnia pulex
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5795 , http://hdl.handle.net/10962/d1005483
- Description: Aquatic toxicology has been identified as a valuable tool in the identification and management of chemical pollution in aquatic ecosystems. Standardised methodologies for acute aquatic bioassays have been adopted from international agencies. As a result of these standard methods, the use of laboratory cultured organisms for toxicity testing has been more popular than that of indigenous field-caught organisms. Included in these adopted methods are those for the cultured crustacean Daphnia pUlex. D.pulex is adapted to living in standing water and the suitability of this species to determine toxic effects for South African riverine environments, which are largely flowing, has been questioned. Thus this thesis is a case-study ofthe use of D.pulex and indigenous site-specific macroinvertebrates as toxicity test organisms for setting acute water quality guidelines to protect aquatic ecosystems. The study highlights site-specific problems such as reference sites and organism identification. The acute tolerance of selected indigenous invertebrates was compared to that of D. pulex, using both a single-substance reference toxicant (zinc) and selected whole efiluents. The significance of source population and culture age as a potential source of biological variability between D.pulex cultures was also investigated. D.pulex cultures have been initiated in South Africa from females collected from a number of different local populations; also it is assumed that no genetic change (due to mutation) occurs within a D.pulex culture over time. In order to establish if source population and culture age are a source of biological variability between D.pulex experiments, the acute tolerJuce to zinc of two different D.pulex populations and three different generations within a population were compared. Due to experimental variability results were inconclusive, and differences in tolerance as a result of population difference or culture age could not be determined with confidence. The acute tolerance of D.pulex to a single reference chemical (zinc) and selected whole efiluents was compared to that of selected indigenous invertebrates. Acute 48 h D.pulex zinc tolerance (LC50 range: 0.22 - 0.60 mg/l Zn) was found to be more sensitive than acute 96 h tolerances shown by mayfly species A.fconurus peringueyi (Heptageniidae) (LC50: 17.42 mg/l Zn), Euthrauluselegans (Leptophlebiidae) (LC50: 0.98 mg/IZn), Ba~tidae (LC50: 0.94mg/IZn) and shrimp, Caradina nilotica (Atyidae) (LC50: 3.17 mg/l Zn). This result suggests that guidelines for zinc set using D.pulex will protect the selected indigenous invertebrates. Selected whole eftluents were not acutely toxic to either D.pulex or selected indigenous invertebrates. These experiments were used as a case study for method development regarding the comparative use of D.pulex and indigenous invertebrates in acute whole eftluent toxicity testing. Finally, it is recommended that a suite of indigenous organisms (e.g. macroinvertebrates, fish and algae), as well as laboratory cultured D.pulex, be used in the initial setting of guidelines and that D.pulex be used for routine compliance monitoring. It is futher recommended that a suite of available monitoring methods, such as chemical and biomonitoring methodologies, be used in conjuction with toxicity testing in water quality management.
- Full Text:
Assessing alternative assessment: students' experiences of the different forms of assessment in a Bachelor of Education course
- Authors: Hendricks, Monica
- Date: 2000
- Subjects: Education, Higher -- South Africa -- Evaluation Educational tests and measurements -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1424 , http://hdl.handle.net/10962/d1003305
- Description: In this study I examine the current alternative forms of assessment that were employed in the foundation year of the Bachelor of Education course at Rhodes University in 1998. Since assessment is concerned with ascertaining the amount, and kind, of learning that has taken place, it links learning and teaching. As my role in the course was academic development, I was interested in the nature ofthe development that the course promoted, for lecturers and students. My main intention was to gain insight into students' experiences of the assessment practices. To this end I selected six students, photocopied all their academic writing for the year and interviewed them. In addition, to provide a holistic picture of assessment and marking, I interviewed the six lecturers who team-taught the course. The data thus included the course assignments of the six students and an interview with each student as well as with the course lecturers. The findings show that though policy documents advocate alternative forms of assessment, implementing such assessment is a complex matter for both teachers and students.
- Full Text:
- Authors: Hendricks, Monica
- Date: 2000
- Subjects: Education, Higher -- South Africa -- Evaluation Educational tests and measurements -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1424 , http://hdl.handle.net/10962/d1003305
- Description: In this study I examine the current alternative forms of assessment that were employed in the foundation year of the Bachelor of Education course at Rhodes University in 1998. Since assessment is concerned with ascertaining the amount, and kind, of learning that has taken place, it links learning and teaching. As my role in the course was academic development, I was interested in the nature ofthe development that the course promoted, for lecturers and students. My main intention was to gain insight into students' experiences of the assessment practices. To this end I selected six students, photocopied all their academic writing for the year and interviewed them. In addition, to provide a holistic picture of assessment and marking, I interviewed the six lecturers who team-taught the course. The data thus included the course assignments of the six students and an interview with each student as well as with the course lecturers. The findings show that though policy documents advocate alternative forms of assessment, implementing such assessment is a complex matter for both teachers and students.
- Full Text:
The solubility enhancement and the stability assessment of rifampicin, isoniazid and pyrazinamide in aqueous media
- Authors: Chen, Yu-Jen
- Date: 2000
- Subjects: Gel permeation chromatography , Rifampin , Isoniazid , Pyridazines
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4346 , http://hdl.handle.net/10962/d1005009 , Gel permeation chromatography , Rifampin , Isoniazid , Pyridazines
- Description: Tuberculosis (TB) is a highly contagious disease caused by the bacterium known as Mycobacterium tuberculosis which is widely spread in South Africa, especially in the rural areas of the Western Province. Rifampicin, isoniazid and pyrazinamide are the three most effective drugs against this organism. However, most of the current commercial anti-TB formulations are inconvenient to administrate. This results in patient non-compliance which has increased with incomplete tuberculosis treatment and further has intensified the mortality rate. The matter is especially severe amongst the paediatric and geriatric patients. Therefore, creating a "user-friendly" but non-alcoholic liquid formulation should improve the whole situation. The key to a successful formulation relies on sufficient concentrations of the drugs within the formulation together with acceptable stability of these drugs. Therefore, during the pre-formulation stage, the solubility and stability studies of rifampicin, isoniazid and pyrazinamide are to be conducted. Rifampicin, isoniazid and pyrazinamide were fully characterized and identified by means of spectroscopic and thermal techniques. A HPLC method for simultaneous analysis of the three drugs was developed and validated. This HPLC method was employed for all the solubility and stability assessments. Unbuffered HPLC water of pH value 7.01 was chosen as the aqueous solvent. This was decided after the stability of rifampicin, isoniazid and pyrazinamide was studied at a pH range of 2 to 10. The solubility and the stability studies of rifampicin, isoniazid, pyrazinamide, rifampicin with isoniazid, rifampicin with pyrazinamide, isoniazid with pyrazinamide and rifampicin combined with both isoniazid and pyrazinamide were performed in the presence of various agents. These agents can be categorized into three groups: the surfactants (poloxamer 188, poloxamer 407 and sorbitol) which could increase the intrinsic solubility or the drugs by altering the surface tensions of the aqueous solution medium, the suspending agents (carbopol 934 and carbopol 974P) which could enable the amount of dosage required to be homogeneously suspended in the formulation without considering the low intrinsic solubility factor of the drugs, and the complexing agents (ß-cyclodextrin, hydroxypropyl-ß-cyclodextrin and -cyclodextrin) which could initiated the inclusion complex between the host cyclodextrin and the drugs, thus further enhance the solubility of the drugs . The stability assessments were performed after 7-days stability trail with the HPLC method developed. Each drug/combination of drugs were stored in closed ampoules and subjected to 25, 40 and 60° C with or without nitrogen flushing while in the presence of the above mentioned agents. While assessing the solubility/stability of the drugs in the presence of the above mentioned surfactants, the phase-solubility curves indicate that both rifampicin and pyrazinamide fail to achieve the desired concentration. Moreover, the stability-time plots clearly indicate that these surfactants fail to enhance the general stabilities of the drugs. When the stabilizing effects of the above mentioned suspending agents were investigated, it was found that although the desired concentration could be easily accomplished by suspending the drug in the aqueous carbopol solutions, the stabilities of the different drug combinations were still below the regulatory level. Cyclodextrins are well known to form inclusion complexes with less polar drug molecules. The inclusion complexation could enhance both the solubility and the stability of the included drug molecules. The computer force field generated models of the cyclodextrin-drug were used to predict the complexation sites. The results indicated the all the inclusion complexation between the drugs and the cyclodextrins were favourable, but do not necessary protect the potential degradation sites of the drugs. The stability results confirmed the above findings as the cyclodextrins did not enhance the stability of the drugs. Various drug-drug interaction pathways were also predicted from the experimental observations which clearly indicated the stability reductions of these drugs in combination. This leads to the conclusion that a liquid formulation combining rifampicin, isoniazid and pyrazinamide should not initiate the use of aqueous solutions as the protic ions of the solution are able to initiate the degradation of these drugs.
- Full Text:
- Authors: Chen, Yu-Jen
- Date: 2000
- Subjects: Gel permeation chromatography , Rifampin , Isoniazid , Pyridazines
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4346 , http://hdl.handle.net/10962/d1005009 , Gel permeation chromatography , Rifampin , Isoniazid , Pyridazines
- Description: Tuberculosis (TB) is a highly contagious disease caused by the bacterium known as Mycobacterium tuberculosis which is widely spread in South Africa, especially in the rural areas of the Western Province. Rifampicin, isoniazid and pyrazinamide are the three most effective drugs against this organism. However, most of the current commercial anti-TB formulations are inconvenient to administrate. This results in patient non-compliance which has increased with incomplete tuberculosis treatment and further has intensified the mortality rate. The matter is especially severe amongst the paediatric and geriatric patients. Therefore, creating a "user-friendly" but non-alcoholic liquid formulation should improve the whole situation. The key to a successful formulation relies on sufficient concentrations of the drugs within the formulation together with acceptable stability of these drugs. Therefore, during the pre-formulation stage, the solubility and stability studies of rifampicin, isoniazid and pyrazinamide are to be conducted. Rifampicin, isoniazid and pyrazinamide were fully characterized and identified by means of spectroscopic and thermal techniques. A HPLC method for simultaneous analysis of the three drugs was developed and validated. This HPLC method was employed for all the solubility and stability assessments. Unbuffered HPLC water of pH value 7.01 was chosen as the aqueous solvent. This was decided after the stability of rifampicin, isoniazid and pyrazinamide was studied at a pH range of 2 to 10. The solubility and the stability studies of rifampicin, isoniazid, pyrazinamide, rifampicin with isoniazid, rifampicin with pyrazinamide, isoniazid with pyrazinamide and rifampicin combined with both isoniazid and pyrazinamide were performed in the presence of various agents. These agents can be categorized into three groups: the surfactants (poloxamer 188, poloxamer 407 and sorbitol) which could increase the intrinsic solubility or the drugs by altering the surface tensions of the aqueous solution medium, the suspending agents (carbopol 934 and carbopol 974P) which could enable the amount of dosage required to be homogeneously suspended in the formulation without considering the low intrinsic solubility factor of the drugs, and the complexing agents (ß-cyclodextrin, hydroxypropyl-ß-cyclodextrin and -cyclodextrin) which could initiated the inclusion complex between the host cyclodextrin and the drugs, thus further enhance the solubility of the drugs . The stability assessments were performed after 7-days stability trail with the HPLC method developed. Each drug/combination of drugs were stored in closed ampoules and subjected to 25, 40 and 60° C with or without nitrogen flushing while in the presence of the above mentioned agents. While assessing the solubility/stability of the drugs in the presence of the above mentioned surfactants, the phase-solubility curves indicate that both rifampicin and pyrazinamide fail to achieve the desired concentration. Moreover, the stability-time plots clearly indicate that these surfactants fail to enhance the general stabilities of the drugs. When the stabilizing effects of the above mentioned suspending agents were investigated, it was found that although the desired concentration could be easily accomplished by suspending the drug in the aqueous carbopol solutions, the stabilities of the different drug combinations were still below the regulatory level. Cyclodextrins are well known to form inclusion complexes with less polar drug molecules. The inclusion complexation could enhance both the solubility and the stability of the included drug molecules. The computer force field generated models of the cyclodextrin-drug were used to predict the complexation sites. The results indicated the all the inclusion complexation between the drugs and the cyclodextrins were favourable, but do not necessary protect the potential degradation sites of the drugs. The stability results confirmed the above findings as the cyclodextrins did not enhance the stability of the drugs. Various drug-drug interaction pathways were also predicted from the experimental observations which clearly indicated the stability reductions of these drugs in combination. This leads to the conclusion that a liquid formulation combining rifampicin, isoniazid and pyrazinamide should not initiate the use of aqueous solutions as the protic ions of the solution are able to initiate the degradation of these drugs.
- Full Text:
Environmental influences on the daytime vertical distribution of Cape hakes and implications for demersal trawl estimates of hake abundance off the west coast of South Africa
- Authors: Maree, R C
- Date: 2000
- Subjects: Hake , Fisheries -- Environmental aspects -- South Africa , Fisheries -- South Africa , Trawls and trawling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5278 , http://hdl.handle.net/10962/d1005122
- Description: The demersal fishery off the west coast of South Africa experiences decreased catches per unit effort of hake, Merluccius capensis and M. paradoxus, following the onset of strong south easterly winds. Research has demonstrated that, during daylight hours, Cape hakes migrate vertically in the water column in response to strong south easterly winds, decreasing their availability to the bottom trawl. Hydroacoustic, trawl and environmental data were collected off the West Coast during both calm and wind-swept periods in an attempt to understand the forces that initiate this behaviour, its spatial variability and the implications for demersal trawl estimates of abundance. Near-bottom currents appear to be the primary factor influencing the vertical distribution of the demersal fish community, of which hake constitutes a large proportion, during daylight hours. Correlation between wind and near-bottom currents suggest that the poleward component of the currents increase in velocity within eight hours following the onset of south easterly winds. The fish avoid boundary layers where currents change direction and speed dramatically, and seem to concentrate in waters with relatively stable current regimes. This result questions the assumption of CPUE-based assessment models that hake availability to the bottom trawl is constant or varies randomly. The incorporation of acoustic assessment techniques to demersal surveys has potential, but may be most valuable by supplementing swept-area estimates of abundance, since the sampling efficiency of these methods varies within the water column. The incorporation of wind indices and gear performance data to Cape hake assessment models have been identified as useful considerations for the future.
- Full Text:
- Authors: Maree, R C
- Date: 2000
- Subjects: Hake , Fisheries -- Environmental aspects -- South Africa , Fisheries -- South Africa , Trawls and trawling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5278 , http://hdl.handle.net/10962/d1005122
- Description: The demersal fishery off the west coast of South Africa experiences decreased catches per unit effort of hake, Merluccius capensis and M. paradoxus, following the onset of strong south easterly winds. Research has demonstrated that, during daylight hours, Cape hakes migrate vertically in the water column in response to strong south easterly winds, decreasing their availability to the bottom trawl. Hydroacoustic, trawl and environmental data were collected off the West Coast during both calm and wind-swept periods in an attempt to understand the forces that initiate this behaviour, its spatial variability and the implications for demersal trawl estimates of abundance. Near-bottom currents appear to be the primary factor influencing the vertical distribution of the demersal fish community, of which hake constitutes a large proportion, during daylight hours. Correlation between wind and near-bottom currents suggest that the poleward component of the currents increase in velocity within eight hours following the onset of south easterly winds. The fish avoid boundary layers where currents change direction and speed dramatically, and seem to concentrate in waters with relatively stable current regimes. This result questions the assumption of CPUE-based assessment models that hake availability to the bottom trawl is constant or varies randomly. The incorporation of acoustic assessment techniques to demersal surveys has potential, but may be most valuable by supplementing swept-area estimates of abundance, since the sampling efficiency of these methods varies within the water column. The incorporation of wind indices and gear performance data to Cape hake assessment models have been identified as useful considerations for the future.
- Full Text:
An exploration of female physicality and psyche and how these inform art-making
- Authors: Poole, Tanya Katherine
- Date: 2000
- Subjects: Women artists , Women artists -- Psychology , Rego, Paula -- Interviews , Feminism , Women -- Sexual behavior , Sherman, Cindy , Saville, Jenny, 1970-
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2419 , http://hdl.handle.net/10962/d1002215 , Women artists , Women artists -- Psychology , Rego, Paula -- Interviews , Feminism , Women -- Sexual behavior , Sherman, Cindy , Saville, Jenny, 1970-
- Description: This thesis proposes that female physicality informs the psyche and thus in turn, art-making. My argument will be shown to be apposite and informative to the discussion of the work of Paula Rego, Jenny Saville and Cindy Sherman. Furthermore such an understanding is helpful to a reading of my practice. In examining issues of identity, which contribute to the formulation of a distinctly female psyche, I will base my critique on the philosophical positions of Sartre, de Beauvoir and Paglia.
- Full Text:
- Authors: Poole, Tanya Katherine
- Date: 2000
- Subjects: Women artists , Women artists -- Psychology , Rego, Paula -- Interviews , Feminism , Women -- Sexual behavior , Sherman, Cindy , Saville, Jenny, 1970-
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2419 , http://hdl.handle.net/10962/d1002215 , Women artists , Women artists -- Psychology , Rego, Paula -- Interviews , Feminism , Women -- Sexual behavior , Sherman, Cindy , Saville, Jenny, 1970-
- Description: This thesis proposes that female physicality informs the psyche and thus in turn, art-making. My argument will be shown to be apposite and informative to the discussion of the work of Paula Rego, Jenny Saville and Cindy Sherman. Furthermore such an understanding is helpful to a reading of my practice. In examining issues of identity, which contribute to the formulation of a distinctly female psyche, I will base my critique on the philosophical positions of Sartre, de Beauvoir and Paglia.
- Full Text:
The dynamics of an emerging outcomes-based educational approach in a second language English classroom
- Authors: Westphal, Vivian
- Date: 2000
- Subjects: English language -- Study and teaching -- Foreign speakers -- South Africa Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1502 , http://hdl.handle.net/10962/d1003384
- Description: Curriculum 2005 and outcomes-based education was introduced to South African educators in 1996 by the Minister of Education, Prof. S.M.E. Bengu as an alternative to the racially divided education system prior to the first democratic elections of 1995. The new curriculum was designed to transform the education system into a more equitable system by focussing on creating learners who would become creative thinkers, independent, productive workers and responsible, non-racial citizens. Learners would take a greater role in their own education and teachers would take on new roles as facilitators in the learning process. The new approach was introduced into grade 1 in 1998 and grade 2 in 1999. By using a modified ethnographic approach, this research project studies how one teacher has begun to think about Curriculum 2005 and implement an OBE approach to ESL teaching in a grade 2 classroom. It also focuses on gaining insights into how the teacher has attempted to make sense of the new curriculum in terms of her current practice and the training she has received in OBE. The ethnographic approach of the thesis has allowed the researcher to draw on many forms of data providing a holistic view. Tentative findings show that the teacher is experiencing difficulty in “unpacking” the underlying principles of OBE in terms of her current methods of teaching ESL. She continues to work from tacit knowledge. Because she has received very little training in OBE, she lacks the tools to become a more reflective practitioner. Despite this, her ESL lessons show a positive communicative approach to language teaching by focusing on stories, rhymes and songs as comprehensible input for the learners. The findings of this thesis tentatively suggest that unless teachers are given more adequate training and learning support materials, their classroom practices will remain relatively unchanged.
- Full Text:
- Authors: Westphal, Vivian
- Date: 2000
- Subjects: English language -- Study and teaching -- Foreign speakers -- South Africa Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1502 , http://hdl.handle.net/10962/d1003384
- Description: Curriculum 2005 and outcomes-based education was introduced to South African educators in 1996 by the Minister of Education, Prof. S.M.E. Bengu as an alternative to the racially divided education system prior to the first democratic elections of 1995. The new curriculum was designed to transform the education system into a more equitable system by focussing on creating learners who would become creative thinkers, independent, productive workers and responsible, non-racial citizens. Learners would take a greater role in their own education and teachers would take on new roles as facilitators in the learning process. The new approach was introduced into grade 1 in 1998 and grade 2 in 1999. By using a modified ethnographic approach, this research project studies how one teacher has begun to think about Curriculum 2005 and implement an OBE approach to ESL teaching in a grade 2 classroom. It also focuses on gaining insights into how the teacher has attempted to make sense of the new curriculum in terms of her current practice and the training she has received in OBE. The ethnographic approach of the thesis has allowed the researcher to draw on many forms of data providing a holistic view. Tentative findings show that the teacher is experiencing difficulty in “unpacking” the underlying principles of OBE in terms of her current methods of teaching ESL. She continues to work from tacit knowledge. Because she has received very little training in OBE, she lacks the tools to become a more reflective practitioner. Despite this, her ESL lessons show a positive communicative approach to language teaching by focusing on stories, rhymes and songs as comprehensible input for the learners. The findings of this thesis tentatively suggest that unless teachers are given more adequate training and learning support materials, their classroom practices will remain relatively unchanged.
- Full Text:
The structure and function of the gametes of the striped field mouse (Rhabdomys pumilio)
- Authors: Tinney, Gregory Michael
- Date: 2000
- Subjects: Gametes , Microtus , Mice
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5774 , http://hdl.handle.net/10962/d1005462 , Gametes , Microtus , Mice
- Description: This study was initiated in an attempt toadd the four-striped field mouse (Rhabdomys pumilio) to the small group of mammals that are used to study and develop assisted reproductive technologies. To accomplish this, a complete knowledge of both the male and female gametes was necessary, as well as a repeatable and successful IVF protocol. The gametes of the field mouse, both the falciformspermand the mature oocytes, were shown to be similar in several respects to those of many other rodent species. The induction of both the capacitated state and the acrosome reaction in the sperm were readily achieved. The success of retrieving mature oocytes was very low, with the rare occurrence of polar bodies within ovulated oocytes. The difficulties with oocytes was either related to the lack of a regular oestrous cycle, or to the hormonal regime used to induce superovulation. Although several protocols were used to accomplish superovulation in this species, it was seldom achieved. In in vitro fertilization trials, sperm were found to attach to both the cumulus oophorus and the zona pellucida of the oocytes. However, fertilization was never accomplished. This failure to achieve fertilization was probably related to the immaturity of the oocytes. Without further studies on Rhabdomys pumilio and further attempts at accomplishing in vitro fertilization, it would seem that this species would not easily be introduced as an animalmodelfor assisted reproduction.
- Full Text:
- Authors: Tinney, Gregory Michael
- Date: 2000
- Subjects: Gametes , Microtus , Mice
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5774 , http://hdl.handle.net/10962/d1005462 , Gametes , Microtus , Mice
- Description: This study was initiated in an attempt toadd the four-striped field mouse (Rhabdomys pumilio) to the small group of mammals that are used to study and develop assisted reproductive technologies. To accomplish this, a complete knowledge of both the male and female gametes was necessary, as well as a repeatable and successful IVF protocol. The gametes of the field mouse, both the falciformspermand the mature oocytes, were shown to be similar in several respects to those of many other rodent species. The induction of both the capacitated state and the acrosome reaction in the sperm were readily achieved. The success of retrieving mature oocytes was very low, with the rare occurrence of polar bodies within ovulated oocytes. The difficulties with oocytes was either related to the lack of a regular oestrous cycle, or to the hormonal regime used to induce superovulation. Although several protocols were used to accomplish superovulation in this species, it was seldom achieved. In in vitro fertilization trials, sperm were found to attach to both the cumulus oophorus and the zona pellucida of the oocytes. However, fertilization was never accomplished. This failure to achieve fertilization was probably related to the immaturity of the oocytes. Without further studies on Rhabdomys pumilio and further attempts at accomplishing in vitro fertilization, it would seem that this species would not easily be introduced as an animalmodelfor assisted reproduction.
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Healing at the margins: discourses of culture and illness in psychiatrists', psychologists' and indigenous healers' talk about collaboration
- Authors: Yen, Jeffery
- Date: 2000
- Subjects: Traditional medicine -- South Africa , Medical policy -- South Africa , Mental health -- South Africa , Healers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3090 , http://hdl.handle.net/10962/d1002600 , Traditional medicine -- South Africa , Medical policy -- South Africa , Mental health -- South Africa , Healers -- South Africa
- Description: This dissertation explores discourses about culture and illness in the talk of mental health professionals and indigenous healers. It represents an attempt to situate the issue of indigenous healing in South Africa within a particular strand of critical discourse analytic research. In the context of current deliberations on the value, or otherwise, of indigenous healing in a changing health and specifically mental health system, the talk of both mental health practitioners and indigenous healers as they conceptualise “disorder”, and discuss possibilities for collaboration, is chosen as a specific focus for this study. Disputes over what constitutes “disorder” both within mental health, and between mental health and indigenous healing are an important site in which the negotiation of power relations between mental health professionals and indigenous healers is played out. The results of this study suggest that despite the construction of cogent commendations for the inclusion of indigenous healing in mental health, it remains largely marginalised within talk about mental health practice. While this study reproduces to some extent the marginalisation of indigenous healing discourse, it also examines some of the discursive practices and methodological difficulties implicated in its marginalisation. However, in the context of “cultural pride strategies” associated with talk about an African Renaissance, indigenous healing may also function as a site of assertion of African power and resistance in its construction as an essentially African enterprise. At the same time, it may achieve disciplinary effects consonant with cultural pride strategies, in constructing afflictions in terms of neglect of, or disloyalty to cultural tradition. These results are discussed in terms of the methodological difficulties associated with interviewing and discourse analysis of translated texts, which contributes to difficulties with articulating indigenous healing discourse in a way that challenges the dominant psychiatric discourses implicated in its marginalisation within mental health. It concludes with recommendations for future research which addresses indigenous healing discourse in its own terms, and examines its operation as a disciplinary apparatus in South African society.
- Full Text:
- Authors: Yen, Jeffery
- Date: 2000
- Subjects: Traditional medicine -- South Africa , Medical policy -- South Africa , Mental health -- South Africa , Healers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3090 , http://hdl.handle.net/10962/d1002600 , Traditional medicine -- South Africa , Medical policy -- South Africa , Mental health -- South Africa , Healers -- South Africa
- Description: This dissertation explores discourses about culture and illness in the talk of mental health professionals and indigenous healers. It represents an attempt to situate the issue of indigenous healing in South Africa within a particular strand of critical discourse analytic research. In the context of current deliberations on the value, or otherwise, of indigenous healing in a changing health and specifically mental health system, the talk of both mental health practitioners and indigenous healers as they conceptualise “disorder”, and discuss possibilities for collaboration, is chosen as a specific focus for this study. Disputes over what constitutes “disorder” both within mental health, and between mental health and indigenous healing are an important site in which the negotiation of power relations between mental health professionals and indigenous healers is played out. The results of this study suggest that despite the construction of cogent commendations for the inclusion of indigenous healing in mental health, it remains largely marginalised within talk about mental health practice. While this study reproduces to some extent the marginalisation of indigenous healing discourse, it also examines some of the discursive practices and methodological difficulties implicated in its marginalisation. However, in the context of “cultural pride strategies” associated with talk about an African Renaissance, indigenous healing may also function as a site of assertion of African power and resistance in its construction as an essentially African enterprise. At the same time, it may achieve disciplinary effects consonant with cultural pride strategies, in constructing afflictions in terms of neglect of, or disloyalty to cultural tradition. These results are discussed in terms of the methodological difficulties associated with interviewing and discourse analysis of translated texts, which contributes to difficulties with articulating indigenous healing discourse in a way that challenges the dominant psychiatric discourses implicated in its marginalisation within mental health. It concludes with recommendations for future research which addresses indigenous healing discourse in its own terms, and examines its operation as a disciplinary apparatus in South African society.
- Full Text: