Influence of blue/green versus red and white light sources on human dark adaptation and other selected visual functions
- Authors: Hendrikse, Egbert Johannes
- Date: 1994
- Subjects: Light -- Physiological effect Lighting Vision -- Research Night vision Visual acuity Color -- Physiological effect Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5146 , http://hdl.handle.net/10962/d1009497
- Description: Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
- Full Text:
- Date Issued: 1994
- Authors: Hendrikse, Egbert Johannes
- Date: 1994
- Subjects: Light -- Physiological effect Lighting Vision -- Research Night vision Visual acuity Color -- Physiological effect Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5146 , http://hdl.handle.net/10962/d1009497
- Description: Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
- Full Text:
- Date Issued: 1994
Insertion of a measurable function
- Authors: Kotzé, W , Kubiak, T
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6785 , http://hdl.handle.net/10962/d1006928
- Description: Some theorems on the existence of continuous real-valued functions on a topological space (for example, insertion, extension, and separation theorems) can be proved without involving uncountable unions of open sets. In particular, it is shown that well-known characterizations of normality (for example the Katětov-Tong insertion theorem, the Tietze extension theorem, Urysohn's lemma) are characterizations of normal σ-rings. Likewise, similar theorems about extremally disconnected spaces are true for σ-rings of a certain type. This σ-ring approach leads to general results on the existence of functions of class α.
- Full Text:
- Date Issued: 1994
- Authors: Kotzé, W , Kubiak, T
- Date: 1994
- Language: English
- Type: Article
- Identifier: vital:6785 , http://hdl.handle.net/10962/d1006928
- Description: Some theorems on the existence of continuous real-valued functions on a topological space (for example, insertion, extension, and separation theorems) can be proved without involving uncountable unions of open sets. In particular, it is shown that well-known characterizations of normality (for example the Katětov-Tong insertion theorem, the Tietze extension theorem, Urysohn's lemma) are characterizations of normal σ-rings. Likewise, similar theorems about extremally disconnected spaces are true for σ-rings of a certain type. This σ-ring approach leads to general results on the existence of functions of class α.
- Full Text:
- Date Issued: 1994
Investigating an environmental education curriculum to a developing society's needs: a case study of the programme offered at the Pilanesberg National Park, Bophuthatswana
- Authors: Johnson, Steven Robert
- Date: 1994
- Subjects: Environmental education Environmental education -- Curricula -- South Africa -- Bophuthatswana Environmental education -- Curricula -- Case studies Pilanesberg National Park (South Africa)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1585 , http://hdl.handle.net/10962/d1003467
- Description: The Environmental Education programme offered at the Gold Fields Environmental Education Centre (GFEE Centre) in the Pilanesberg National Park, Bophuthatswana, was initiated in response to requests from schools in Bophuthatswana to visit game reserves as 'syllabus related school activities'. Evaluative research into the GFEE Centre programme by an external researcher indicated that the learning experiences largely concentrated on cognitive development, and neglected to influence affective and psychomotor development. After a number of adaptations to the programme, which emphasised a more child-centred approach it was realised that little was known about the background and learning needs of the predominantly BaTswana school children. It was felt by the researcher that the learning activities provided at the GFEE Centre could also possibly be biased by a Western, scientific orientation which possibly lacked relevance to the cultural backgrounds of the pupils. The researcher used an action research approach in a number of workshops with a purposive sample of BaTswana primary school teachers, to gather data. The teachers were encouraged to critically reflect on the background and learning-needs of BaTswana children, with specific regard to environmental issues and worldviews. The information provided by the teachers' reflective deliberations and a seperate research project with school children, indicated that primary school children in Bophuthatswana tend to follow accepted human development patterns in their perceptions of the environment. The influence of either a predominantly rural or urban upbringing during a child's early formative years was considered by the teachers to be significant in determining worldviews, and culture was considered to have an influence on children's learning processes. Their beliefs and experiences were used by them in generating suggestions to correct the GFEE Centre programme. The teachers' also highlighted the fact that there were a number of socio-cultural and institutional issues which influenced the effectiveness of the GFEE Centre programme.
- Full Text:
- Date Issued: 1994
- Authors: Johnson, Steven Robert
- Date: 1994
- Subjects: Environmental education Environmental education -- Curricula -- South Africa -- Bophuthatswana Environmental education -- Curricula -- Case studies Pilanesberg National Park (South Africa)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1585 , http://hdl.handle.net/10962/d1003467
- Description: The Environmental Education programme offered at the Gold Fields Environmental Education Centre (GFEE Centre) in the Pilanesberg National Park, Bophuthatswana, was initiated in response to requests from schools in Bophuthatswana to visit game reserves as 'syllabus related school activities'. Evaluative research into the GFEE Centre programme by an external researcher indicated that the learning experiences largely concentrated on cognitive development, and neglected to influence affective and psychomotor development. After a number of adaptations to the programme, which emphasised a more child-centred approach it was realised that little was known about the background and learning needs of the predominantly BaTswana school children. It was felt by the researcher that the learning activities provided at the GFEE Centre could also possibly be biased by a Western, scientific orientation which possibly lacked relevance to the cultural backgrounds of the pupils. The researcher used an action research approach in a number of workshops with a purposive sample of BaTswana primary school teachers, to gather data. The teachers were encouraged to critically reflect on the background and learning-needs of BaTswana children, with specific regard to environmental issues and worldviews. The information provided by the teachers' reflective deliberations and a seperate research project with school children, indicated that primary school children in Bophuthatswana tend to follow accepted human development patterns in their perceptions of the environment. The influence of either a predominantly rural or urban upbringing during a child's early formative years was considered by the teachers to be significant in determining worldviews, and culture was considered to have an influence on children's learning processes. Their beliefs and experiences were used by them in generating suggestions to correct the GFEE Centre programme. The teachers' also highlighted the fact that there were a number of socio-cultural and institutional issues which influenced the effectiveness of the GFEE Centre programme.
- Full Text:
- Date Issued: 1994
John N. Muafangejo, 1943-1987 : a perspective on his lino-cuts with special reference to the University of Bophuthatswana Print Collection
- Authors: Cole, Collin
- Date: 1994
- Subjects: Muafangejo, John N., 1943-1987 -- Criticism and interpretation Linoleum block-printing -- Art collections Art, Namibian
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2398 , http://hdl.handle.net/10962/d1002194
- Description: By way of an analysis of the lino-cuts executed by Muafangejo, firstly elements and influences that are evident in terms associated with his works, will be traced, for example 'primitive' and 'traditional' elements. Secondly, the characteristics that are particular to this artist's work will be defined. It is believed that by using this avenue of approach, a clearer understanding of the artist's traditional world and possibly the stylistic placement of the artist can be attained. However, to rely only on historical and cultural influences to give a perspective of his work, will not be sufficient. It will only highlight a portion of the evidence needed to fully understand his work. (From the introduction).
- Full Text:
- Date Issued: 1994
- Authors: Cole, Collin
- Date: 1994
- Subjects: Muafangejo, John N., 1943-1987 -- Criticism and interpretation Linoleum block-printing -- Art collections Art, Namibian
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2398 , http://hdl.handle.net/10962/d1002194
- Description: By way of an analysis of the lino-cuts executed by Muafangejo, firstly elements and influences that are evident in terms associated with his works, will be traced, for example 'primitive' and 'traditional' elements. Secondly, the characteristics that are particular to this artist's work will be defined. It is believed that by using this avenue of approach, a clearer understanding of the artist's traditional world and possibly the stylistic placement of the artist can be attained. However, to rely only on historical and cultural influences to give a perspective of his work, will not be sufficient. It will only highlight a portion of the evidence needed to fully understand his work. (From the introduction).
- Full Text:
- Date Issued: 1994
La possibilité de la révélation et du salut dans les religions non chrétiennes : le debat protestant contemporain
- Authors: Matungulu, Givule Floribert
- Date: 1994
- Language: French
- Type: Thesis , Masters , MTh
- Identifier: vital:1307 , http://hdl.handle.net/10962/d1018215
- Full Text:
- Date Issued: 1994
- Authors: Matungulu, Givule Floribert
- Date: 1994
- Language: French
- Type: Thesis , Masters , MTh
- Identifier: vital:1307 , http://hdl.handle.net/10962/d1018215
- Full Text:
- Date Issued: 1994
Lifestyle orientation of high versus low achievers in traditional school sports: an holistic analysis
- Authors: Davies, Simeon
- Date: 1994
- Subjects: School sports Achievement motivation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5147 , http://hdl.handle.net/10962/d1009501
- Description: One hundred and four subjects aged 16-18 years volunteered to participate in this study which sought to identify via an holistic model those factors that characterise the lifestyle orientations of high and low achievers (male and female) in traditional school sport. Subjects were evaluated with respect to their anthropometric, physiological, psychological and perceptual responses. The data were statistically analyzed by one way ANOVAS for significant differences in the following pairs; males and females, high and low achievers, Mhi (male high achievers) and Mlo (male low achievers), and Fhi (female high achievers) and Flo (female low achievers). Anthropometric results indicate that Fhi and Flo were significantly different in their stature, mass and body fat, while Mhi and Mlo show no significant differences. A greater disparity existed between VO, max of Fhi and Flo compared with Mhi and Mlo, along with trends in heart rate and RPE responses that were also more divergent. Psychological responses indicate that Fhi and Flo were significantly different in five of the seven sub-domains of CATPA, while Mhi and Mlo were only identifiable in one. In the PSPP Fhi and Flo were significantly different in all five subscales, while Mhi and Mlo in only two. This contrast in variability between the paired group analysis of Fhi and Flo as compared to Mhi and Mlo appears throughout the data.
- Full Text:
- Date Issued: 1994
- Authors: Davies, Simeon
- Date: 1994
- Subjects: School sports Achievement motivation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5147 , http://hdl.handle.net/10962/d1009501
- Description: One hundred and four subjects aged 16-18 years volunteered to participate in this study which sought to identify via an holistic model those factors that characterise the lifestyle orientations of high and low achievers (male and female) in traditional school sport. Subjects were evaluated with respect to their anthropometric, physiological, psychological and perceptual responses. The data were statistically analyzed by one way ANOVAS for significant differences in the following pairs; males and females, high and low achievers, Mhi (male high achievers) and Mlo (male low achievers), and Fhi (female high achievers) and Flo (female low achievers). Anthropometric results indicate that Fhi and Flo were significantly different in their stature, mass and body fat, while Mhi and Mlo show no significant differences. A greater disparity existed between VO, max of Fhi and Flo compared with Mhi and Mlo, along with trends in heart rate and RPE responses that were also more divergent. Psychological responses indicate that Fhi and Flo were significantly different in five of the seven sub-domains of CATPA, while Mhi and Mlo were only identifiable in one. In the PSPP Fhi and Flo were significantly different in all five subscales, while Mhi and Mlo in only two. This contrast in variability between the paired group analysis of Fhi and Flo as compared to Mhi and Mlo appears throughout the data.
- Full Text:
- Date Issued: 1994
Local government and coloured residential segregation in Port Elizabeth, 1964-1976
- Authors: Taylor, Beverley J
- Date: 1994
- Language: English
- Type: text , article
- Identifier: vital:7108 , https://doi.org/10.1080/03736245.1994.9713566 , http://hdl.handle.net/10962/d1010736
- Description: preprint , Studies of racial territorial segregation affecting the coloured population in Port Elizabeth tend to perceive it as an outcome of a power struggle between central and local government over the implementation of apartheid legislation. This paper explores the underlying economic forces on the local government to bring about residential segregation and address the coloured housing crisis in the city. It is proposed that whereas central government motives for segregation were primarily political, local government was influenced largely by economic considerations. Local government objectives were severely compromised through both local industrial interests and the implementation of central government Group Areas policies.
- Full Text:
- Date Issued: 1994
- Authors: Taylor, Beverley J
- Date: 1994
- Language: English
- Type: text , article
- Identifier: vital:7108 , https://doi.org/10.1080/03736245.1994.9713566 , http://hdl.handle.net/10962/d1010736
- Description: preprint , Studies of racial territorial segregation affecting the coloured population in Port Elizabeth tend to perceive it as an outcome of a power struggle between central and local government over the implementation of apartheid legislation. This paper explores the underlying economic forces on the local government to bring about residential segregation and address the coloured housing crisis in the city. It is proposed that whereas central government motives for segregation were primarily political, local government was influenced largely by economic considerations. Local government objectives were severely compromised through both local industrial interests and the implementation of central government Group Areas policies.
- Full Text:
- Date Issued: 1994
Maps for Africa
- Authors: Cosser, M , West, Walter O
- Date: 1994
- Language: English
- Type: Text
- Identifier: vital:555 , http://hdl.handle.net/10962/d1020643
- Description: [Introduction] Opening address by Oakley West at exhibition: Maps: Knowledge and Power - A Teaching Exhibition at the Albany Museum, November 1992. Maps, like art, reflect man's perception of the world in which he lives. Often they are coloured both by the known and unknown, by fact and fancy, myth and mystery. Maps are not just merely bits of paper. They are, and have been, important instruments in conquest and empire building. They reflect not only the perceived glory of war and occupation, but survival under siege, the protection or defence of people, property and resources, and, believe it or not, the accidental inheritance of territory, like India. Maps reflect the build-up of nations bent on expansion, resulting in the dreadful years of trench warfare in 1914 - 1918. And who of us can honestly admit that we knew exactly where Kuwait was before that conflict began? Thus in many cases lands were often first claimed on paper before they were effectively occupied. It has been said that no place is truly discovered until it has been mapped and as much as guns and warships, they have played significant roles in manifesting the realities of conquest and empire building. Maps are storehouses of knowledge and information and often it is in that very knowledge that lies the power to conquer, control, defend, divide or develop, to govern or administer or even mislead or misinform. This exhibition attempts to trace almost 2 000 years of cartography. It starts with the great insights of Claudius Ptolomy and his Geographia, continues through the retrogressive perceptions of the Church fathers and their decrees that Jerusalem was the centre of the world, to the perception of a flat Earth and a rather whimsical look at modern "upside-down" cartography which has proved to be only 300 years late in its conception. One can explore the opening up of the dark continent of Africa with its myths and mysteries, the source of the Nile, Mountains of the Moon and the mythical kingdom of Monomatapa. One can "see" the gradual growth of knowledge as first the coasts and later the interior was discovered and made known by men like Diaz, Da Gama, Livingstone, Stanley and Andersson. The discoveries of these explorers were recorded in the great maps of cartographers like John Arrowsmith and Henry Hall, the former incidentally never ever having visited Africa. A quantum leap takes us to some of the newest techniques, the satellite image, which still reflects the historical heritage in the shapes and patterns formed, in what has become known as Settler Country, from as early as the 1800s. By these images one is still able to appreciate the ravages of drought, overgrazing and perhaps the mismanagement of natural resources. Maps show us a different Grahamstown, a Graham's Town lit by gaslamp light. They help us to "see" prison gangs building the Queen's Road to Fort Beaufort, or appreciate the scramble for river frontage farming land. We see the early conceptualization of a harbour scheme at the mouth of the Kowie River, dreamed of by those intent on opening up a gateway to the Eastern Frontier through its wide waters. (A scheme, incidentally, which finally found a different, but nonetheless effective, realisation in the Marina built in the 1990s). Dreams were dreamed of a wide-spread colonial administration, though not without its nostalgic overtones: King William's Town would be the principal town in the county of Middlesex and Komga that of the county Cambridge in British Kaffraria! One can trace in maps the expanding horizons of the colonial powers as they appropriated land in the name of civilisation. As the church and the courts moved in to replace tribal customs and laws, maps reflected the more tangible results of expansion - telegraph, road and rail networks, as well as the more abstract and intangible - the spread of violence. On the other hand, we can follow the development of a great city, the city of London, though almost 400 years, witnessing the growth of its urban sprawl, the depiction of the famous bridges over. the Thames and who could not but be thrilled by the panoramic sweep of London from the Houses of Parliament through St Pauls to the sailing ship harbour, cartography par excellence which evidences the birth of a rail system with engines looking distinctly more akin to Stevenson's rocket than the locomotives we are used to seeing. An exceptionally fine relief model of the Western and Southern Cape coastal area serves to highlight the unending struggle of cartographers to portray that troublesome third dimension, height, on flat pieces of paper. Such struggles are revealed both in maps of topographic landscape as well as the urban complex - some successful, some not so. Finally, the exhibition touches lightly on the wonders of satellite imagery and the coming of the computer to cartography, as in all things. An attempt is made to explain in simple terms the art, science and technology of the cartographer in the production of the multicoloured maps we are all so familiar with.
- Full Text:
- Date Issued: 1994
- Authors: Cosser, M , West, Walter O
- Date: 1994
- Language: English
- Type: Text
- Identifier: vital:555 , http://hdl.handle.net/10962/d1020643
- Description: [Introduction] Opening address by Oakley West at exhibition: Maps: Knowledge and Power - A Teaching Exhibition at the Albany Museum, November 1992. Maps, like art, reflect man's perception of the world in which he lives. Often they are coloured both by the known and unknown, by fact and fancy, myth and mystery. Maps are not just merely bits of paper. They are, and have been, important instruments in conquest and empire building. They reflect not only the perceived glory of war and occupation, but survival under siege, the protection or defence of people, property and resources, and, believe it or not, the accidental inheritance of territory, like India. Maps reflect the build-up of nations bent on expansion, resulting in the dreadful years of trench warfare in 1914 - 1918. And who of us can honestly admit that we knew exactly where Kuwait was before that conflict began? Thus in many cases lands were often first claimed on paper before they were effectively occupied. It has been said that no place is truly discovered until it has been mapped and as much as guns and warships, they have played significant roles in manifesting the realities of conquest and empire building. Maps are storehouses of knowledge and information and often it is in that very knowledge that lies the power to conquer, control, defend, divide or develop, to govern or administer or even mislead or misinform. This exhibition attempts to trace almost 2 000 years of cartography. It starts with the great insights of Claudius Ptolomy and his Geographia, continues through the retrogressive perceptions of the Church fathers and their decrees that Jerusalem was the centre of the world, to the perception of a flat Earth and a rather whimsical look at modern "upside-down" cartography which has proved to be only 300 years late in its conception. One can explore the opening up of the dark continent of Africa with its myths and mysteries, the source of the Nile, Mountains of the Moon and the mythical kingdom of Monomatapa. One can "see" the gradual growth of knowledge as first the coasts and later the interior was discovered and made known by men like Diaz, Da Gama, Livingstone, Stanley and Andersson. The discoveries of these explorers were recorded in the great maps of cartographers like John Arrowsmith and Henry Hall, the former incidentally never ever having visited Africa. A quantum leap takes us to some of the newest techniques, the satellite image, which still reflects the historical heritage in the shapes and patterns formed, in what has become known as Settler Country, from as early as the 1800s. By these images one is still able to appreciate the ravages of drought, overgrazing and perhaps the mismanagement of natural resources. Maps show us a different Grahamstown, a Graham's Town lit by gaslamp light. They help us to "see" prison gangs building the Queen's Road to Fort Beaufort, or appreciate the scramble for river frontage farming land. We see the early conceptualization of a harbour scheme at the mouth of the Kowie River, dreamed of by those intent on opening up a gateway to the Eastern Frontier through its wide waters. (A scheme, incidentally, which finally found a different, but nonetheless effective, realisation in the Marina built in the 1990s). Dreams were dreamed of a wide-spread colonial administration, though not without its nostalgic overtones: King William's Town would be the principal town in the county of Middlesex and Komga that of the county Cambridge in British Kaffraria! One can trace in maps the expanding horizons of the colonial powers as they appropriated land in the name of civilisation. As the church and the courts moved in to replace tribal customs and laws, maps reflected the more tangible results of expansion - telegraph, road and rail networks, as well as the more abstract and intangible - the spread of violence. On the other hand, we can follow the development of a great city, the city of London, though almost 400 years, witnessing the growth of its urban sprawl, the depiction of the famous bridges over. the Thames and who could not but be thrilled by the panoramic sweep of London from the Houses of Parliament through St Pauls to the sailing ship harbour, cartography par excellence which evidences the birth of a rail system with engines looking distinctly more akin to Stevenson's rocket than the locomotives we are used to seeing. An exceptionally fine relief model of the Western and Southern Cape coastal area serves to highlight the unending struggle of cartographers to portray that troublesome third dimension, height, on flat pieces of paper. Such struggles are revealed both in maps of topographic landscape as well as the urban complex - some successful, some not so. Finally, the exhibition touches lightly on the wonders of satellite imagery and the coming of the computer to cartography, as in all things. An attempt is made to explain in simple terms the art, science and technology of the cartographer in the production of the multicoloured maps we are all so familiar with.
- Full Text:
- Date Issued: 1994
Means and ends: the Development Forum movement in the greater Eastern Cape region
- Authors: Davies, William J
- Date: 1994
- Subjects: Community development -- South Africa
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/1741 , vital:20221 , ISBN 0868102709
- Description: The emergence of development and other kinds of forums in South Africa is but one manifestation of the process of dynamic change that characterises the nineties. The Eastern Cape is no exception in this regard and, in terms of regional forums, its people and institutions have been in the vanguard of the phenomenon in the country. By providing opportunities for discussion, consultation and interaction at an unprecedented scale, the forum movement has brought many diverse people together and forged hitherto unlikely relationships. The Development Studies Unit has been part of that process, and this Working Paper reflects upon the origins, intent and prospects of the forum movement up to the run-up to the April 1994 elections. It is a baseline document that will be revisited in due course to assess the extent to which the movement has made a difference and where its subsequent future lies. The work was undertaken principally with the DSU’s own resources, together with assistance from the Urban Foundation, and reflects the outcome of a significant proportion of the DSU’s recent research involvements. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Date Issued: 1994
- Authors: Davies, William J
- Date: 1994
- Subjects: Community development -- South Africa
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/1741 , vital:20221 , ISBN 0868102709
- Description: The emergence of development and other kinds of forums in South Africa is but one manifestation of the process of dynamic change that characterises the nineties. The Eastern Cape is no exception in this regard and, in terms of regional forums, its people and institutions have been in the vanguard of the phenomenon in the country. By providing opportunities for discussion, consultation and interaction at an unprecedented scale, the forum movement has brought many diverse people together and forged hitherto unlikely relationships. The Development Studies Unit has been part of that process, and this Working Paper reflects upon the origins, intent and prospects of the forum movement up to the run-up to the April 1994 elections. It is a baseline document that will be revisited in due course to assess the extent to which the movement has made a difference and where its subsequent future lies. The work was undertaken principally with the DSU’s own resources, together with assistance from the Urban Foundation, and reflects the outcome of a significant proportion of the DSU’s recent research involvements. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
- Full Text:
- Date Issued: 1994
Measures and determinants of productivity growth in the South African manufacturing sector
- Authors: Wright, Anthony John
- Date: 1994
- Subjects: Industrial productivity -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1019 , http://hdl.handle.net/10962/d1002754 , Industrial productivity -- South Africa
- Description: The neoclassical "sources-of-growth" approach is applied to derive total factor productivity (TFP) growth measures for manufacturing industries in South Africa. Although South Africa's recorded industrial TFP growth measures have been persistently low in absolute terms, this performance is not significantly worse than the industrial TFP growth performance of other developing countries. In some periods there is evidence of a significant variability in TFP performance across industries. The measures also indicate that TFP growth has worsened in the 1980s, particularly in the intermediate-capital intensive and labour intensive industries. However, there are various problems with interpreting neoclassical TFP growth measures as indicators of production efficiency. In fact, as TFP growth is derived as a residual, it may measure many factors besides production efficiency. Alternative growth theories are used to assess the fundamental determinants of productivity growth. These provide a more plausible conceptualisation of the process by which productivity growth is generated than the neoclassical growth theory does. However, this analysis also provides little empirical evidence of which underlying factors have had the most influence on productivity growth in South African manufacturing. Hence, the relative importance of possible candidates can only really be assessed qualitatively and on the basis of micro evidence. However, these assessments, and the assumptions underlying the postulated causal connections (between the identified factors and productivity growth), have a major impact on policy design. In this respect, on the basis of the framework provided by the evolutionary and other recent growth theories, various policy implications are drawn, and these are contrasted with the policy proposals of other South African analysts. This thesis concludes that policies need to be designed with the central objective of enhancing the technological capabilities of South African firms. Trade policies will not be sufficient for achieving this objective. Education and training policies, technology, competition and labour market policies are also crucial. However, since the fundamental causes of productivity growth remain somewhat of a mystery, there is a need to be sceptical of simple policy prescriptions. In this respect, this thesis is highly critical of the World Bank's position that productivity gains will be reaped from the exposure of firms to international competition that trade liberalisation policies entail.
- Full Text:
- Date Issued: 1994
- Authors: Wright, Anthony John
- Date: 1994
- Subjects: Industrial productivity -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1019 , http://hdl.handle.net/10962/d1002754 , Industrial productivity -- South Africa
- Description: The neoclassical "sources-of-growth" approach is applied to derive total factor productivity (TFP) growth measures for manufacturing industries in South Africa. Although South Africa's recorded industrial TFP growth measures have been persistently low in absolute terms, this performance is not significantly worse than the industrial TFP growth performance of other developing countries. In some periods there is evidence of a significant variability in TFP performance across industries. The measures also indicate that TFP growth has worsened in the 1980s, particularly in the intermediate-capital intensive and labour intensive industries. However, there are various problems with interpreting neoclassical TFP growth measures as indicators of production efficiency. In fact, as TFP growth is derived as a residual, it may measure many factors besides production efficiency. Alternative growth theories are used to assess the fundamental determinants of productivity growth. These provide a more plausible conceptualisation of the process by which productivity growth is generated than the neoclassical growth theory does. However, this analysis also provides little empirical evidence of which underlying factors have had the most influence on productivity growth in South African manufacturing. Hence, the relative importance of possible candidates can only really be assessed qualitatively and on the basis of micro evidence. However, these assessments, and the assumptions underlying the postulated causal connections (between the identified factors and productivity growth), have a major impact on policy design. In this respect, on the basis of the framework provided by the evolutionary and other recent growth theories, various policy implications are drawn, and these are contrasted with the policy proposals of other South African analysts. This thesis concludes that policies need to be designed with the central objective of enhancing the technological capabilities of South African firms. Trade policies will not be sufficient for achieving this objective. Education and training policies, technology, competition and labour market policies are also crucial. However, since the fundamental causes of productivity growth remain somewhat of a mystery, there is a need to be sceptical of simple policy prescriptions. In this respect, this thesis is highly critical of the World Bank's position that productivity gains will be reaped from the exposure of firms to international competition that trade liberalisation policies entail.
- Full Text:
- Date Issued: 1994
Metabolic responses to in vitro zinc supplementation
- Authors: Steel, Helen Carolyn
- Date: 1994
- Subjects: Zinc in the body , Zinc -- Physiological effect , Cancer -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4040 , http://hdl.handle.net/10962/d1004101 , Zinc in the body , Zinc -- Physiological effect , Cancer -- Research
- Description: The present study was carried out to determine the effects and possible mechanism of action of zinc supplementation on the in vitro growth of malignant murine melanoma (B16) and non-malignant monkey kidney (LLCMK) cells. Cell culture studies showed that zinc supplementation significantly inhibited B16 growth at all the concentrations studied (1, 3, 5 and lOμg/ml). Zinc was also found to inhibit the growth of the LLCMK cells, although to a lesser extent than the B16 cells. Possible evidence of mobilisation of the essential fatty acids from the membrane phospholipid stores was noted in both cell types. This effect was, however, greater in the B16 cells. Δ⁶-desaturase activity was found to be significantly lower in the B16 cells than in the LLCMK cells (p ≥ 0.05). Zinc supplementation resulted in an increase in the enzymes activity in the LLCMK cells and, at high concentrations, in the B16 cells. An estimation of elongase and Δ⁶-desaturase activity with zinc supplementation indicated that zinc had little or no effect on the activity of these enzymes. B16 cells were found to have higher levels of free radicals than the LLCMK cells. Zinc supplementation resulted in increased free radical formation in the B16 cells, while no effect was observed in the LLCMK cells. Lipid peroxidation increased in both cell types with increased zinc concentrations. The observed effect of zinc supplementation on cell growth may involve these elevated levels of lipid peroxides. CycIo-oxygenase activity was found to be greater in the B16 cells than the LLCMK cells. The activity of the enzyme increased with higher concentrations of zinc (lOμg/ml) in both cell types. Prostaglandin E, levels were found to be lower in the B16 cells compared to the LLCMK cells. The levels of prostaglandin E, in both cell types appeared to be dependent on the levels of the polyunsaturated fatty acid precursors to the prostaglandins. Zinc was found to inhibit the activity of the enzyme adenylate cyclase in both cell types. The cAMP levels in the LLCMK cells were also found to decrease with zinc supplementation. In the case of the B16 cells, cAMP levels increased at low concentrations of zinc despite a decrease in adenyl ate cyclase activity, suggesting a possible inhibition of cAMP phosphodiesterase activity at these concentrations of zinc. It is concluded that although zinc supplementation does have an effect on cell growth, this effect is not mediated through the activation of adenylate cyclase by the prostaglandins resulting in elevated levels of cAMP. A possible mechanism involving lipid peroxidation is proposed.
- Full Text:
- Date Issued: 1994
- Authors: Steel, Helen Carolyn
- Date: 1994
- Subjects: Zinc in the body , Zinc -- Physiological effect , Cancer -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4040 , http://hdl.handle.net/10962/d1004101 , Zinc in the body , Zinc -- Physiological effect , Cancer -- Research
- Description: The present study was carried out to determine the effects and possible mechanism of action of zinc supplementation on the in vitro growth of malignant murine melanoma (B16) and non-malignant monkey kidney (LLCMK) cells. Cell culture studies showed that zinc supplementation significantly inhibited B16 growth at all the concentrations studied (1, 3, 5 and lOμg/ml). Zinc was also found to inhibit the growth of the LLCMK cells, although to a lesser extent than the B16 cells. Possible evidence of mobilisation of the essential fatty acids from the membrane phospholipid stores was noted in both cell types. This effect was, however, greater in the B16 cells. Δ⁶-desaturase activity was found to be significantly lower in the B16 cells than in the LLCMK cells (p ≥ 0.05). Zinc supplementation resulted in an increase in the enzymes activity in the LLCMK cells and, at high concentrations, in the B16 cells. An estimation of elongase and Δ⁶-desaturase activity with zinc supplementation indicated that zinc had little or no effect on the activity of these enzymes. B16 cells were found to have higher levels of free radicals than the LLCMK cells. Zinc supplementation resulted in increased free radical formation in the B16 cells, while no effect was observed in the LLCMK cells. Lipid peroxidation increased in both cell types with increased zinc concentrations. The observed effect of zinc supplementation on cell growth may involve these elevated levels of lipid peroxides. CycIo-oxygenase activity was found to be greater in the B16 cells than the LLCMK cells. The activity of the enzyme increased with higher concentrations of zinc (lOμg/ml) in both cell types. Prostaglandin E, levels were found to be lower in the B16 cells compared to the LLCMK cells. The levels of prostaglandin E, in both cell types appeared to be dependent on the levels of the polyunsaturated fatty acid precursors to the prostaglandins. Zinc was found to inhibit the activity of the enzyme adenylate cyclase in both cell types. The cAMP levels in the LLCMK cells were also found to decrease with zinc supplementation. In the case of the B16 cells, cAMP levels increased at low concentrations of zinc despite a decrease in adenyl ate cyclase activity, suggesting a possible inhibition of cAMP phosphodiesterase activity at these concentrations of zinc. It is concluded that although zinc supplementation does have an effect on cell growth, this effect is not mediated through the activation of adenylate cyclase by the prostaglandins resulting in elevated levels of cAMP. A possible mechanism involving lipid peroxidation is proposed.
- Full Text:
- Date Issued: 1994
Methods for assessing the susceptibility of freshwater ecosystems in Southern Africa to invasion by alien aquatic animals
- Authors: De Moor, Irene J
- Date: 1994
- Subjects: Biotic communities -- South Africa , Animal introduction , Freshwater ecology -- Africa, Southern , Animal introduction -- South Africa , Geographic information systems
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5300 , http://hdl.handle.net/10962/d1005145
- Description: Two methods for predicting regions susceptible to invasion by alien aquatic animals were developed for southern Africa (excluding Zimbabwe and Mozambique). In the "traditional" (data-poor) approach, distributions of three categories of alien "indicator" species (warm mesothermal, cold stenothermal and eurytopic) were compared to seven existing biogeographical models of distribution patterns of various animals in southern Africa. On the basis of these comparisons a synthesis model was developed which divided southern Africa into seven regions characterised by their susceptibility to invasion by alien aquatic animals with particular habitat requirements. In the "data-rich," geographic information systems (GIS) approach, the distribution of trout (Oncorhynchus mykiss and Salmo trutta) in selected "sampled regions" was related to elevation (as a surrogate of water temperature) and median annual rainfall (MAR) (as a surrogate of water availability). Using concentration analysis, optimum conditions for trout were identified. Regions within a larger "predictive area" which satisfied these conditions, were plotted as a digital map using the IDRISI package. Using this method seven models of potential trout distribution were generated for the following regions: northern Natal (two); southern Natal/Lesotho/Transkei (three), eastern Cape (two) and western Cape (two). Since two of the models were used to refine the methods, only five models were considered for the final assessment. In a modification of the GIS method, another model of potential trout distribution, based on mean monthly July minimum air temperature and MAR parameters, was developed for the region bounded by 29º - 34º S and 26 º - 32°E. This model showed marked similarities to another model, developed for the region bounded by 29 º - 32°S and 26º - 32°E, which was based on elevation and MAR parameters. The validity of the models developed was assessed by independent experts. Of the six models considered, four received favourable judgements, one was equivocal and one was judged to be poor. Based on these assessments it was concluded that the GIS method has credibility and could be used to develop a "data-rich" model of the susceptibility of southern Africa to invasion by alien aquatic animals. This method represents an alternative to the bioclimatic matching approach developed by scientists in Australia. The GIS method has a number of advantages over the "traditional" method: it is more amenable to testing, has greater flexibility, stores more information, produces images of a finer resolution, and can be easily updated. The traditional method has the advantage of being less expensive and requiring a less extensive database.
- Full Text:
- Date Issued: 1994
- Authors: De Moor, Irene J
- Date: 1994
- Subjects: Biotic communities -- South Africa , Animal introduction , Freshwater ecology -- Africa, Southern , Animal introduction -- South Africa , Geographic information systems
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5300 , http://hdl.handle.net/10962/d1005145
- Description: Two methods for predicting regions susceptible to invasion by alien aquatic animals were developed for southern Africa (excluding Zimbabwe and Mozambique). In the "traditional" (data-poor) approach, distributions of three categories of alien "indicator" species (warm mesothermal, cold stenothermal and eurytopic) were compared to seven existing biogeographical models of distribution patterns of various animals in southern Africa. On the basis of these comparisons a synthesis model was developed which divided southern Africa into seven regions characterised by their susceptibility to invasion by alien aquatic animals with particular habitat requirements. In the "data-rich," geographic information systems (GIS) approach, the distribution of trout (Oncorhynchus mykiss and Salmo trutta) in selected "sampled regions" was related to elevation (as a surrogate of water temperature) and median annual rainfall (MAR) (as a surrogate of water availability). Using concentration analysis, optimum conditions for trout were identified. Regions within a larger "predictive area" which satisfied these conditions, were plotted as a digital map using the IDRISI package. Using this method seven models of potential trout distribution were generated for the following regions: northern Natal (two); southern Natal/Lesotho/Transkei (three), eastern Cape (two) and western Cape (two). Since two of the models were used to refine the methods, only five models were considered for the final assessment. In a modification of the GIS method, another model of potential trout distribution, based on mean monthly July minimum air temperature and MAR parameters, was developed for the region bounded by 29º - 34º S and 26 º - 32°E. This model showed marked similarities to another model, developed for the region bounded by 29 º - 32°S and 26º - 32°E, which was based on elevation and MAR parameters. The validity of the models developed was assessed by independent experts. Of the six models considered, four received favourable judgements, one was equivocal and one was judged to be poor. Based on these assessments it was concluded that the GIS method has credibility and could be used to develop a "data-rich" model of the susceptibility of southern Africa to invasion by alien aquatic animals. This method represents an alternative to the bioclimatic matching approach developed by scientists in Australia. The GIS method has a number of advantages over the "traditional" method: it is more amenable to testing, has greater flexibility, stores more information, produces images of a finer resolution, and can be easily updated. The traditional method has the advantage of being less expensive and requiring a less extensive database.
- Full Text:
- Date Issued: 1994
Motion arrested : body politics and the struggle for a physical theatre
- Authors: Gordon, G E
- Date: 1994
- Subjects: Movement (Acting) , Experimental drama
- Language: English
- Type: Text
- Identifier: vital:571 , http://hdl.handle.net/10962/d1005946
- Description: [From the text]: Physical theatre does have a political agenda but it is not to provide a counter argument in terms of the body/mind divide. It utilises this encompassing approach to argue for the legitimacy and potential of the body and to counteract the argument for the supremacy of the mind over the body. The body is mobilised as a source of power to question conventional views on race, gender, sexual stereotyping and sexuality. This new "physicality" should not be viewed as a negation of the word, the text or the rational, but should be seen rather as an integration of the physical with the vocal, mental and emotional resources of the performer.
- Full Text:
- Date Issued: 1994
- Authors: Gordon, G E
- Date: 1994
- Subjects: Movement (Acting) , Experimental drama
- Language: English
- Type: Text
- Identifier: vital:571 , http://hdl.handle.net/10962/d1005946
- Description: [From the text]: Physical theatre does have a political agenda but it is not to provide a counter argument in terms of the body/mind divide. It utilises this encompassing approach to argue for the legitimacy and potential of the body and to counteract the argument for the supremacy of the mind over the body. The body is mobilised as a source of power to question conventional views on race, gender, sexual stereotyping and sexuality. This new "physicality" should not be viewed as a negation of the word, the text or the rational, but should be seen rather as an integration of the physical with the vocal, mental and emotional resources of the performer.
- Full Text:
- Date Issued: 1994
National Labour and Economic Development Institute Annual report
- NALEDI
- Authors: NALEDI
- Date: 1994
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151179 , vital:39036
- Description: The National Labour & Economic Development Institute (NALEDI) opened its doors in October 1993 and began its research programme at the beginning of 1994. NALEDI is an initiative of the Congress of South African Trade Unions (Cosatu). Its aim is to conduct policy-relevant research of interest to the labour movement. The origins of the institute date back to Cosatu's 1991 national congress which recognised the need to improve the research capacity of the federation. A feasibility study was conducted. This attempted to define the research needs of the federation and its affiliates. It also examined the experience of other union- linked institutes such as FAFO in Norway and DESEP in Brazil, and explored Cosatu's experience with service organisations and associated research groups. In early 1993 Cosatu's central executive committee endorsed the establishment of a labour research institute and raised funds (primarily from the Dutch union movement the FNV) to commence operations. Jeremy Baskin was appointed to get the institute functioning and a board was appointed to assist.
- Full Text:
- Date Issued: 1994
- Authors: NALEDI
- Date: 1994
- Subjects: NALEDI
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/151179 , vital:39036
- Description: The National Labour & Economic Development Institute (NALEDI) opened its doors in October 1993 and began its research programme at the beginning of 1994. NALEDI is an initiative of the Congress of South African Trade Unions (Cosatu). Its aim is to conduct policy-relevant research of interest to the labour movement. The origins of the institute date back to Cosatu's 1991 national congress which recognised the need to improve the research capacity of the federation. A feasibility study was conducted. This attempted to define the research needs of the federation and its affiliates. It also examined the experience of other union- linked institutes such as FAFO in Norway and DESEP in Brazil, and explored Cosatu's experience with service organisations and associated research groups. In early 1993 Cosatu's central executive committee endorsed the establishment of a labour research institute and raised funds (primarily from the Dutch union movement the FNV) to commence operations. Jeremy Baskin was appointed to get the institute functioning and a board was appointed to assist.
- Full Text:
- Date Issued: 1994
NUMSA - Gender and Globalisation group discussion
- NUMSA
- Authors: NUMSA
- Date: 1994
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/117816 , vital:34561
- Description: In the past, the government in many countries provided social welfare benefits to people. These benefits included things like public health care and free education. This is now changing in many countries. Governments today provide fewer services and benefits to people. Instead they hand this job over the private sector. This means that people have to start paying before they get a service. If families can’t afford to pay private companies for these services, then someone in the family has to fill the gap. Generally it is women who have to: care for the sick when it is too expensive to take them to hospital, collect firewood because electricity is too expensive, walk miles to collect water from the river because piped water is too expensive. Many governments have been forced to change the role they play in the economy by the structural adjustment programmes (SAPs) that the International Monetary Fund (IMF) imposes on them as one of the conditions for lending them money
- Full Text:
- Date Issued: 1994
- Authors: NUMSA
- Date: 1994
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/117816 , vital:34561
- Description: In the past, the government in many countries provided social welfare benefits to people. These benefits included things like public health care and free education. This is now changing in many countries. Governments today provide fewer services and benefits to people. Instead they hand this job over the private sector. This means that people have to start paying before they get a service. If families can’t afford to pay private companies for these services, then someone in the family has to fill the gap. Generally it is women who have to: care for the sick when it is too expensive to take them to hospital, collect firewood because electricity is too expensive, walk miles to collect water from the river because piped water is too expensive. Many governments have been forced to change the role they play in the economy by the structural adjustment programmes (SAPs) that the International Monetary Fund (IMF) imposes on them as one of the conditions for lending them money
- Full Text:
- Date Issued: 1994
Nutrient supplementation and secondary metaolites in melanoma cells
- Authors: Stoll, Karin Elisabeth
- Date: 1994
- Subjects: Vitamin C -- Therapeutic use Cancer -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4049 , http://hdl.handle.net/10962/d1004110
- Description: Considerable interest exists with regard to the putative therapeutic role of ascorbic acid in various conditions. A condition which has received much attention is cancer, as it is reported that ascorbic acid may be a prophylactic against cancer development. However, the actual involvement of ascorbic acid, an oxidizing/reducing agent, in the development and progression of tumours is presently a subject of much speculation. This study initially addressed the effect of ascorbic acid supplementation over a nutritional concentration range (0 - 100 μg/ml) on the in vitro growth of non-malignant LLCMK and malignant B16 cells. Ascorbic acid supplementation of these two cell types resulted in an overall decrease in the growth of both types of cells. The actual inhibitory mechanism of ascorbic acid on cell growth was not clear. Further study attempted to define and explain a mechanism responsible for this effect. Ascorbic acid has a role in the maintenance of tissue integrity and host defences, thus providing a rational basis for examining its relationship to cancer. Ascorbic acid is lcnown to be essential for the structural integrity of the intercellular matrix of the cells, the latter being a complex aqueous gel containing, amongst other compounds, fats and prostaglandins. Fats and prostaglandins have diverse effects on. membrane stability, enzyme activity and secondary messengers within cells. Hence, this study investigated the effect of ascorbic acid supplementation on certain enzymes and secondary metabolites within the cells, which had the potential to be involved in the control of cell growth. Throughout this study, emphasis was placed on the Bl6 melanoma cells as ascorbic acid supplementation did not significantly affect levels of secondary metabolites within the non-malignant LLCMK cells. Ascorbic acid supplementation of the B16 cells resulted in significant increases in adenylate cyclase activity and cyclic adenosine monophosphate levels, witb a significant decrease in Bl6 cell growth in that particular experiment. As cyclic adenosine monophosphate has a regulatory role in the cell cycle, this study suggested that the inhibitory effect of ascorbic acid supplementation on cell growth was mediated tbrough a final effect provided by the second messenger, cyclic adenosine monophosphate. However, clarification of tbe mechanism of tbe effect of ascorbic acid on adenylate cyclase activity was required. Hence, a further study investigated prostaglandin E₂ levels, as tbese affect adenylate cyclase activity. Prostaglandin E₂ levels were also found to be inversely related to Bl6 cell growth with ascorbic acid supplementation. It thus appeared tbat adenylate cyclase activity was dependent on prostaglandin E₂ levels in the B16 cells, and further study showed that tbis was indeed the case. Here, higher levels of prostaglandin E₂ supplementation of the Bl6 cells inhibited cell growth significantly and also significantly increased adenylate cyclase activity. Arachidonic acid is the precursor of prostaglandin E₂. In the presence of ascorbic acid supplementation, the percentage arachidonic acid composition of the Bl6 cells was inversely correlated with cell growth. Hence, prostaglandin E₂ levels in ascorbic acid supplemented B16 cells appeared dependent on tbe amount of precursor present. This was confirmed when Bl6 cells were supplemented with arachidonic acid. The latter had an inhibitory effect on Bl6 cell growth and also stimulated prostaglandin E₂ production. The cause of tbe inverse relationship between B16 cell growth and arachidonic acid composition with ascorbic acid supplementation was furtber investigated and found to be dependent on tbe uptake of arachidonic acid and other essential fatty acids from tbe medium. The enzymes phospholipase A₂ delta-5 and delta-6-desaturase, and elongase which could influence arachidonic acid levels were not affected to any extent by ascorbic acid supplementation and therefore did not influence the inverse relationship between B16 cell growth and arachidonic acid. Hence, it can be concluded that the effect of ascorbic acid supplementation on the BI6 cells is mediated, in part at least, by cyclic adenosine monophosphate. However, this is not the result of a direct effect of ascorbic acid supplementation. The initial effect of ascorbic acid supplementation concerns fatty acid - in particular arachidonic acid - uptake from the medium, with subsequent cascade effects On secondary metabolites, ultimately affecting the cellular levels of cyclic adenosine monophosphate.
- Full Text:
- Date Issued: 1994
- Authors: Stoll, Karin Elisabeth
- Date: 1994
- Subjects: Vitamin C -- Therapeutic use Cancer -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4049 , http://hdl.handle.net/10962/d1004110
- Description: Considerable interest exists with regard to the putative therapeutic role of ascorbic acid in various conditions. A condition which has received much attention is cancer, as it is reported that ascorbic acid may be a prophylactic against cancer development. However, the actual involvement of ascorbic acid, an oxidizing/reducing agent, in the development and progression of tumours is presently a subject of much speculation. This study initially addressed the effect of ascorbic acid supplementation over a nutritional concentration range (0 - 100 μg/ml) on the in vitro growth of non-malignant LLCMK and malignant B16 cells. Ascorbic acid supplementation of these two cell types resulted in an overall decrease in the growth of both types of cells. The actual inhibitory mechanism of ascorbic acid on cell growth was not clear. Further study attempted to define and explain a mechanism responsible for this effect. Ascorbic acid has a role in the maintenance of tissue integrity and host defences, thus providing a rational basis for examining its relationship to cancer. Ascorbic acid is lcnown to be essential for the structural integrity of the intercellular matrix of the cells, the latter being a complex aqueous gel containing, amongst other compounds, fats and prostaglandins. Fats and prostaglandins have diverse effects on. membrane stability, enzyme activity and secondary messengers within cells. Hence, this study investigated the effect of ascorbic acid supplementation on certain enzymes and secondary metabolites within the cells, which had the potential to be involved in the control of cell growth. Throughout this study, emphasis was placed on the Bl6 melanoma cells as ascorbic acid supplementation did not significantly affect levels of secondary metabolites within the non-malignant LLCMK cells. Ascorbic acid supplementation of the B16 cells resulted in significant increases in adenylate cyclase activity and cyclic adenosine monophosphate levels, witb a significant decrease in Bl6 cell growth in that particular experiment. As cyclic adenosine monophosphate has a regulatory role in the cell cycle, this study suggested that the inhibitory effect of ascorbic acid supplementation on cell growth was mediated tbrough a final effect provided by the second messenger, cyclic adenosine monophosphate. However, clarification of tbe mechanism of tbe effect of ascorbic acid on adenylate cyclase activity was required. Hence, a further study investigated prostaglandin E₂ levels, as tbese affect adenylate cyclase activity. Prostaglandin E₂ levels were also found to be inversely related to Bl6 cell growth with ascorbic acid supplementation. It thus appeared tbat adenylate cyclase activity was dependent on prostaglandin E₂ levels in the B16 cells, and further study showed that tbis was indeed the case. Here, higher levels of prostaglandin E₂ supplementation of the Bl6 cells inhibited cell growth significantly and also significantly increased adenylate cyclase activity. Arachidonic acid is the precursor of prostaglandin E₂. In the presence of ascorbic acid supplementation, the percentage arachidonic acid composition of the Bl6 cells was inversely correlated with cell growth. Hence, prostaglandin E₂ levels in ascorbic acid supplemented B16 cells appeared dependent on tbe amount of precursor present. This was confirmed when Bl6 cells were supplemented with arachidonic acid. The latter had an inhibitory effect on Bl6 cell growth and also stimulated prostaglandin E₂ production. The cause of tbe inverse relationship between B16 cell growth and arachidonic acid composition with ascorbic acid supplementation was furtber investigated and found to be dependent on tbe uptake of arachidonic acid and other essential fatty acids from tbe medium. The enzymes phospholipase A₂ delta-5 and delta-6-desaturase, and elongase which could influence arachidonic acid levels were not affected to any extent by ascorbic acid supplementation and therefore did not influence the inverse relationship between B16 cell growth and arachidonic acid. Hence, it can be concluded that the effect of ascorbic acid supplementation on the BI6 cells is mediated, in part at least, by cyclic adenosine monophosphate. However, this is not the result of a direct effect of ascorbic acid supplementation. The initial effect of ascorbic acid supplementation concerns fatty acid - in particular arachidonic acid - uptake from the medium, with subsequent cascade effects On secondary metabolites, ultimately affecting the cellular levels of cyclic adenosine monophosphate.
- Full Text:
- Date Issued: 1994
Parallel implementation of a virtual reality system on a transputer architecture
- Authors: Bangay, Shaun Douglas
- Date: 1994 , 2012-10-11
- Subjects: Virtual reality , Computer simulation , Transputers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4668 , http://hdl.handle.net/10962/d1006687 , Virtual reality , Computer simulation , Transputers
- Description: A Virtual Reality is a computer model of an environment, actual or imagined, presented to a user in as realistic a fashion as possible. Stereo goggles may be used to provide the user with a view of the modelled environment from within the environment, while a data-glove is used to interact with the environment. To simulate reality on a computer, the machine has to produce realistic images rapidly. Such a requirement usually necessitates expensive equipment. This thesis presents an implementation of a virtual reality system on a transputer architecture. The system is general, and is intended to provide support for the development of various virtual environments. The three main components of the system are the output device drivers, the input device drivers, and the virtual world kernel. This last component is responsible for the simulation of the virtual world. The rendering system is described in detail. Various methods for implementing the components of the graphics pipeline are discussed. These are then generalised to make use of the facilities provided by the transputer processor for parallel processing. A number of different decomposition techniques are implemented and compared. The emphasis in this section is on the speed at which the world can be rendered, and the interaction latency involved. In the best case, where almost linear speedup is obtained, a world containing over 250 polygons is rendered at 32 frames/second. The bandwidth of the transputer links is the major factor limiting speedup. A description is given of an input device driver which makes use of a powerglove. Techniques for overcoming the limitations of this device, and for interacting with the virtual world, are discussed. The virtual world kernel is designed to make extensive use of the parallel processing facilities provided by transputers. It is capable of providing support for mUltiple worlds concurrently, and for multiple users interacting with these worlds. Two applications are described that were successfully implemented using this system. The design of the system is compared with other recently developed virtual reality systems. Features that are common or advantageous in each of the systems are discussed. The system described in this thesis compares favourably, particularly in its use of parallel processors. , KMBT_223
- Full Text:
- Date Issued: 1994
- Authors: Bangay, Shaun Douglas
- Date: 1994 , 2012-10-11
- Subjects: Virtual reality , Computer simulation , Transputers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4668 , http://hdl.handle.net/10962/d1006687 , Virtual reality , Computer simulation , Transputers
- Description: A Virtual Reality is a computer model of an environment, actual or imagined, presented to a user in as realistic a fashion as possible. Stereo goggles may be used to provide the user with a view of the modelled environment from within the environment, while a data-glove is used to interact with the environment. To simulate reality on a computer, the machine has to produce realistic images rapidly. Such a requirement usually necessitates expensive equipment. This thesis presents an implementation of a virtual reality system on a transputer architecture. The system is general, and is intended to provide support for the development of various virtual environments. The three main components of the system are the output device drivers, the input device drivers, and the virtual world kernel. This last component is responsible for the simulation of the virtual world. The rendering system is described in detail. Various methods for implementing the components of the graphics pipeline are discussed. These are then generalised to make use of the facilities provided by the transputer processor for parallel processing. A number of different decomposition techniques are implemented and compared. The emphasis in this section is on the speed at which the world can be rendered, and the interaction latency involved. In the best case, where almost linear speedup is obtained, a world containing over 250 polygons is rendered at 32 frames/second. The bandwidth of the transputer links is the major factor limiting speedup. A description is given of an input device driver which makes use of a powerglove. Techniques for overcoming the limitations of this device, and for interacting with the virtual world, are discussed. The virtual world kernel is designed to make extensive use of the parallel processing facilities provided by transputers. It is capable of providing support for mUltiple worlds concurrently, and for multiple users interacting with these worlds. Two applications are described that were successfully implemented using this system. The design of the system is compared with other recently developed virtual reality systems. Features that are common or advantageous in each of the systems are discussed. The system described in this thesis compares favourably, particularly in its use of parallel processors. , KMBT_223
- Full Text:
- Date Issued: 1994
Perceptions of environmental education among senior Ciskeian educationists, and the implications for educational change in the Ciskei region
- Authors: Mkala-Pholo, Pumla Patricia
- Date: 1994
- Subjects: Environmental education -- South Africa -- Ciskei Environmental education -- Curricula -- South Africa -- Ciskei Educators -- South Africa -- Ciskei -- Attitudes Educational planning -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1692 , http://hdl.handle.net/10962/d1003575
- Description: This study was conducted to investigate perceptions of Environmental Education among senior Ciskeian educationists, and to explore the possibility of implementing Environmental Education in school and college curricula in the Ciskei region. Data was collected from interviews with a sample of senior Ciskeian educationists, then analysed and assessed. Corroborating information was obtained from attendance at several regional workshops organised by the Environmental Education Policy Initiative. The data indicated a sound general awareness of environmental problems in Ciskei and a belief in Environmental Education as a means toward their solution. Although the interviewees' understanding of Environmental Education was imperfect, there was broad support for its aims and principles. Since the study was motivated by concern about the implementation of Environmental Education in Ciskei, the results obtained were encouraging.
- Full Text:
- Date Issued: 1994
- Authors: Mkala-Pholo, Pumla Patricia
- Date: 1994
- Subjects: Environmental education -- South Africa -- Ciskei Environmental education -- Curricula -- South Africa -- Ciskei Educators -- South Africa -- Ciskei -- Attitudes Educational planning -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1692 , http://hdl.handle.net/10962/d1003575
- Description: This study was conducted to investigate perceptions of Environmental Education among senior Ciskeian educationists, and to explore the possibility of implementing Environmental Education in school and college curricula in the Ciskei region. Data was collected from interviews with a sample of senior Ciskeian educationists, then analysed and assessed. Corroborating information was obtained from attendance at several regional workshops organised by the Environmental Education Policy Initiative. The data indicated a sound general awareness of environmental problems in Ciskei and a belief in Environmental Education as a means toward their solution. Although the interviewees' understanding of Environmental Education was imperfect, there was broad support for its aims and principles. Since the study was motivated by concern about the implementation of Environmental Education in Ciskei, the results obtained were encouraging.
- Full Text:
- Date Issued: 1994
Perceptions of language teaching in science from student and teacher discourse
- Authors: Garraway, James Windsor
- Date: 1994
- Subjects: Physics -- Study and teaching -- South Africa Language arts -- South Africa Written communication -- Study and teaching -- South Africa Language arts -- Correlation with content subjects -- South Africa Physics teachers -- Language
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1693 , http://hdl.handle.net/10962/d1003576
- Description: The research was concerned with perceptions of language and physics in three strata of participants in a writing across the curriculum teaching course at an intermediate college. The participants were: a language teacher, two physics teachers and a class of twenty physics students - the students were studying in order to enter the Engineering Faculty at the University of Cape Town. The predominant understanding of the teachers was that of a limited interpenetration between the discourse of physics and language teaching. Physics teachers thought that language teachers would experience difficulties with both the concepts and language of physics. In actual practice however, students and the language teacher managed physics knowledge with some degree of success in the language classroom. Some students understood writing as helping them to understand physics. However, the dominant understanding of language was that of knowing the appropriate language of physics for their teachers. An appropriate language understanding was seen as potentially problematic in that it could encourage an unquestioning or monodimensional approach to physics knowledge. As a way around this problem, it was suggested that language teachers teach students to recognise and to use particular genres within science, and to develop their voice within these constraints.
- Full Text:
- Date Issued: 1994
- Authors: Garraway, James Windsor
- Date: 1994
- Subjects: Physics -- Study and teaching -- South Africa Language arts -- South Africa Written communication -- Study and teaching -- South Africa Language arts -- Correlation with content subjects -- South Africa Physics teachers -- Language
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1693 , http://hdl.handle.net/10962/d1003576
- Description: The research was concerned with perceptions of language and physics in three strata of participants in a writing across the curriculum teaching course at an intermediate college. The participants were: a language teacher, two physics teachers and a class of twenty physics students - the students were studying in order to enter the Engineering Faculty at the University of Cape Town. The predominant understanding of the teachers was that of a limited interpenetration between the discourse of physics and language teaching. Physics teachers thought that language teachers would experience difficulties with both the concepts and language of physics. In actual practice however, students and the language teacher managed physics knowledge with some degree of success in the language classroom. Some students understood writing as helping them to understand physics. However, the dominant understanding of language was that of knowing the appropriate language of physics for their teachers. An appropriate language understanding was seen as potentially problematic in that it could encourage an unquestioning or monodimensional approach to physics knowledge. As a way around this problem, it was suggested that language teachers teach students to recognise and to use particular genres within science, and to develop their voice within these constraints.
- Full Text:
- Date Issued: 1994
Perceptions of primary school teachers towards the South African Museum as an environmental education resource
- Authors: Harrison, Jo-Anne Elizabeth
- Date: 1994
- Subjects: Elementary school teachers -- South Africa -- Attitudes South African Museum Environmental education -- South Africa Environmental education -- Curricula -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1694 , http://hdl.handle.net/10962/d1003577
- Description: This study examines the perceptions of a small group of primary school teachers from Gugulethu in Cape Town, of the various exhibitions and education services currently offered at the South African Museum. Their perceptions of proposed services are also examined in order to find out which of these proposals, as well as existing services, best meet the needs expressed by this group of teachers. An attempt was also made to determine their level of understanding of environmental education and awareness of environmental issues. This study suggested the need for greater emphasis to be placed on the 'hands-on' components of the Museum's education programmes. The need for syllabus related and enriching educational programmes and resource materials was also identified. In this regard, the exhibits perceived to be of greatest benefit to the pupils were those relating either to the syllabus or their culture, whilst exhibits seen to be 'out of the pupils' experience' (eg. Fossils) were perceived as unimportant. The teachers also epressed a strong desire for training sessions to be held at the Museum that would help them improve their knowledge of the displays and programmes. It was found that the teachers understanding of environmental education ranged from syllabus-related definitions to more holistic views. The environmental issues perceived to be of greatest importance were mainly social issues such as poverty, violence, child abuse and street children as well as water pollution and cruelty to animals. The production of posters and resource materials, drama, story-telling and programmes for parents were seen to be among the choices most favoured for the Museum to adopt in promoting environmental awareness in the community.
- Full Text:
- Date Issued: 1994
- Authors: Harrison, Jo-Anne Elizabeth
- Date: 1994
- Subjects: Elementary school teachers -- South Africa -- Attitudes South African Museum Environmental education -- South Africa Environmental education -- Curricula -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1694 , http://hdl.handle.net/10962/d1003577
- Description: This study examines the perceptions of a small group of primary school teachers from Gugulethu in Cape Town, of the various exhibitions and education services currently offered at the South African Museum. Their perceptions of proposed services are also examined in order to find out which of these proposals, as well as existing services, best meet the needs expressed by this group of teachers. An attempt was also made to determine their level of understanding of environmental education and awareness of environmental issues. This study suggested the need for greater emphasis to be placed on the 'hands-on' components of the Museum's education programmes. The need for syllabus related and enriching educational programmes and resource materials was also identified. In this regard, the exhibits perceived to be of greatest benefit to the pupils were those relating either to the syllabus or their culture, whilst exhibits seen to be 'out of the pupils' experience' (eg. Fossils) were perceived as unimportant. The teachers also epressed a strong desire for training sessions to be held at the Museum that would help them improve their knowledge of the displays and programmes. It was found that the teachers understanding of environmental education ranged from syllabus-related definitions to more holistic views. The environmental issues perceived to be of greatest importance were mainly social issues such as poverty, violence, child abuse and street children as well as water pollution and cruelty to animals. The production of posters and resource materials, drama, story-telling and programmes for parents were seen to be among the choices most favoured for the Museum to adopt in promoting environmental awareness in the community.
- Full Text:
- Date Issued: 1994