An investigation into the potential immunogenicity of various extracts of the South African bont tick Amblyomma hebraeum
- Authors: Adamson, Deborah Jane
- Date: 1993
- Subjects: Amblyomma -- South Africa , Ticks -- South Africa , Ticks -- Control -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4127 , http://hdl.handle.net/10962/d1015640
- Description: Rabbits and goats were inoculated with crude, membrane-associated and soluble components extracted from unengorged adult females and nymphs of the bont tick Amblyomma hebraeum. Inoculation provided some protection against nymphal infestation, however it had little effect on adult feeding. Histological examination of adults fed on inoculated hosts showed evidence of gut damage. Skin provocation testing with tick extracts elicited a Type I immediate hypersensitivity which was influenced by antihistamine. A delayed skin reaction was also evident. Whether this was attributable to Type III Arthus reaction or Type IV cell-mediated hypersensitivity was not determined. A comparative histological study of sites of tick extract injection, on inoculated and naive hosts, demonstrated the role of eosinophils in the hosts response to tick feeding. Serological examination revealed elevated anti-A hebraeum lgG titres following inoculation. These titres were found to decrease in the ten weeks after inoculation, despite the hosts being repeatedly infested with A hebraeum. Although the IgG titres of naive control hosts increased after each tick infestation, they failed to reach the titres achieved through inoculation. Western blot analysis of serum from inoculated hosts recognized most of the A. hebraeum proteins against which it was screened.
- Full Text:
- Date Issued: 1993
- Authors: Adamson, Deborah Jane
- Date: 1993
- Subjects: Amblyomma -- South Africa , Ticks -- South Africa , Ticks -- Control -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4127 , http://hdl.handle.net/10962/d1015640
- Description: Rabbits and goats were inoculated with crude, membrane-associated and soluble components extracted from unengorged adult females and nymphs of the bont tick Amblyomma hebraeum. Inoculation provided some protection against nymphal infestation, however it had little effect on adult feeding. Histological examination of adults fed on inoculated hosts showed evidence of gut damage. Skin provocation testing with tick extracts elicited a Type I immediate hypersensitivity which was influenced by antihistamine. A delayed skin reaction was also evident. Whether this was attributable to Type III Arthus reaction or Type IV cell-mediated hypersensitivity was not determined. A comparative histological study of sites of tick extract injection, on inoculated and naive hosts, demonstrated the role of eosinophils in the hosts response to tick feeding. Serological examination revealed elevated anti-A hebraeum lgG titres following inoculation. These titres were found to decrease in the ten weeks after inoculation, despite the hosts being repeatedly infested with A hebraeum. Although the IgG titres of naive control hosts increased after each tick infestation, they failed to reach the titres achieved through inoculation. Western blot analysis of serum from inoculated hosts recognized most of the A. hebraeum proteins against which it was screened.
- Full Text:
- Date Issued: 1993
The use of the local environment for teaching geography : a case study in the Umtata administrative area
- Authors: Adonis, Agrinette Nolwandle
- Date: 1993
- Subjects: Geography -- Fieldwork -- Study and teaching Geography -- South Africa -- Study and teaching (Secondary) Black people -- Education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1816 , http://hdl.handle.net/10962/d1003702
- Description: Current theories in geographical education advocate the use of strategies that encourage the pupil to play an active role in learning, thereby making such learning more meaningful and effective. Fieldwork is perceived as one such method. Fieldwork helps pupils acquire and develop understanding of geographical concepts, skills, attitudes and values through their own efforts and involvement. Fieldwork approaches have tended to change with the changing paradigms resulting in the development of approaches that are more pupil and experience oriented. In the South African school geography curricula fieldwork has been explicit since 1985. However, research has shown that in most South African secondary schools fieldwork as a teaching strategy is only applied to a limited extent. Teachers have always used financial constraints and time limitations as explanations for their failure to use fieldwork in teaching geography. This study attempts to demonstrate how the local environment of any school can be used effectively for teaching and learning most aspects of the senior secondary school geography syllabus, thereby alleviating the problems of time and money perceived by teachers as the major constraints inhibiting their use of fieldwork. In order to illustrate the effectiveness of fieldwork in the local environment, this study incorporated an analysis of the current senior secondary school geography syllabus, the identification of potential fieldwork sites in the Umtata District and the development and implementation of three fieldwork units based on three of the sites identified. The analysis of the evaluations of the three fieldwork units by the researcher, the pupils and the non-participant observer revealed that fieldwork conducted in the local environment is highly effective, interesting and rewarding to pupils even when they have no prior experience of fieldwork.
- Full Text:
- Date Issued: 1993
- Authors: Adonis, Agrinette Nolwandle
- Date: 1993
- Subjects: Geography -- Fieldwork -- Study and teaching Geography -- South Africa -- Study and teaching (Secondary) Black people -- Education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1816 , http://hdl.handle.net/10962/d1003702
- Description: Current theories in geographical education advocate the use of strategies that encourage the pupil to play an active role in learning, thereby making such learning more meaningful and effective. Fieldwork is perceived as one such method. Fieldwork helps pupils acquire and develop understanding of geographical concepts, skills, attitudes and values through their own efforts and involvement. Fieldwork approaches have tended to change with the changing paradigms resulting in the development of approaches that are more pupil and experience oriented. In the South African school geography curricula fieldwork has been explicit since 1985. However, research has shown that in most South African secondary schools fieldwork as a teaching strategy is only applied to a limited extent. Teachers have always used financial constraints and time limitations as explanations for their failure to use fieldwork in teaching geography. This study attempts to demonstrate how the local environment of any school can be used effectively for teaching and learning most aspects of the senior secondary school geography syllabus, thereby alleviating the problems of time and money perceived by teachers as the major constraints inhibiting their use of fieldwork. In order to illustrate the effectiveness of fieldwork in the local environment, this study incorporated an analysis of the current senior secondary school geography syllabus, the identification of potential fieldwork sites in the Umtata District and the development and implementation of three fieldwork units based on three of the sites identified. The analysis of the evaluations of the three fieldwork units by the researcher, the pupils and the non-participant observer revealed that fieldwork conducted in the local environment is highly effective, interesting and rewarding to pupils even when they have no prior experience of fieldwork.
- Full Text:
- Date Issued: 1993
A structural study of the capsular antigen of Klebsiella serotype K43
- Authors: Aereboe, Michael
- Date: 1993
- Subjects: Polysaccharides , Klebsiella , Antigens , Enterobacteriaceae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3740 , http://hdl.handle.net/10962/d1003218 , Polysaccharides , Klebsiella , Antigens , Enterobacteriaceae
- Description: This thesis presents a detailed chemical and spectroscopic determination of the capsular, polysaccharide K-antigen isolated from the Klebsiella bacterium, serotype K43 (culture #2482). The repeating unit of the capsular polysaccharide was found to be of the "3 + 2" repeating unit type. A uronic acid was found as part of a disaccharide side chain and the main chain of the polysaccharide was found to be composed of a neutral trisaccharide of mannose and galactose. The work forms part of an ongoing research interest in bacterial polysaccharides of this laboratory and now completes the structural elucidation of all the Klebsiella K-antigens, bar three antigens which were originally assigned to other laboratories. These data together with the respective serological characteristics of each serotype are available to the molecular biologist, and may result in the production of: vaccine(s) against Klebsiella infections, diagnostic products and novel carrier molecules enabling targeted drug delivery.
- Full Text:
- Date Issued: 1993
- Authors: Aereboe, Michael
- Date: 1993
- Subjects: Polysaccharides , Klebsiella , Antigens , Enterobacteriaceae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3740 , http://hdl.handle.net/10962/d1003218 , Polysaccharides , Klebsiella , Antigens , Enterobacteriaceae
- Description: This thesis presents a detailed chemical and spectroscopic determination of the capsular, polysaccharide K-antigen isolated from the Klebsiella bacterium, serotype K43 (culture #2482). The repeating unit of the capsular polysaccharide was found to be of the "3 + 2" repeating unit type. A uronic acid was found as part of a disaccharide side chain and the main chain of the polysaccharide was found to be composed of a neutral trisaccharide of mannose and galactose. The work forms part of an ongoing research interest in bacterial polysaccharides of this laboratory and now completes the structural elucidation of all the Klebsiella K-antigens, bar three antigens which were originally assigned to other laboratories. These data together with the respective serological characteristics of each serotype are available to the molecular biologist, and may result in the production of: vaccine(s) against Klebsiella infections, diagnostic products and novel carrier molecules enabling targeted drug delivery.
- Full Text:
- Date Issued: 1993
"Dudu's Ghost" and the Dedication Orchestra at the 100 Club
- Authors: Alfred, Luke
- Date: 2012 , 1993
- Subjects: McGregor, Chris -- 1936-1990 , Blue Notes (Musical group : South Africa) , Pukwana, Dudu , Jazz , Jazz musicians , Dyani, Johnny Mbizo , Feza, Mongezi , Miller, Harry , Dedication Orchestra , 100 Club
- Language: English
- Type: Article
- Identifier: vital:13472 , http://hdl.handle.net/10962/d1001394 , McGregor, Chris -- 1936-1990 , Blue Notes (Musical group : South Africa) , Pukwana, Dudu , Jazz , Jazz musicians , Dyani, Johnny Mbizo , Feza, Mongezi , Miller, Harry
- Description: The Dedication Orchestra is a group of contemporary English and South African musicians formed in honour of the memory of the Blue Notes, the seminal South African jazz band who found a home from home in London during the early 60s. , Photocopied article from the newspaper SA Times about a concert by the Dedication Orchestra at the 100 Club, London, in honour of the memory of the Blue Notes. There are 5 pictures with the article. The left picture shows Dudu Pukwana playing soprano saxophone, the top middle photo shows Johnny Dyani playing double bass, Mongezi Feza is on the below photo, Chris McGregor is on the top right picture and on the below right photo there is Harry Miller.
- Full Text:
- Date Issued: 1993
- Authors: Alfred, Luke
- Date: 2012 , 1993
- Subjects: McGregor, Chris -- 1936-1990 , Blue Notes (Musical group : South Africa) , Pukwana, Dudu , Jazz , Jazz musicians , Dyani, Johnny Mbizo , Feza, Mongezi , Miller, Harry , Dedication Orchestra , 100 Club
- Language: English
- Type: Article
- Identifier: vital:13472 , http://hdl.handle.net/10962/d1001394 , McGregor, Chris -- 1936-1990 , Blue Notes (Musical group : South Africa) , Pukwana, Dudu , Jazz , Jazz musicians , Dyani, Johnny Mbizo , Feza, Mongezi , Miller, Harry
- Description: The Dedication Orchestra is a group of contemporary English and South African musicians formed in honour of the memory of the Blue Notes, the seminal South African jazz band who found a home from home in London during the early 60s. , Photocopied article from the newspaper SA Times about a concert by the Dedication Orchestra at the 100 Club, London, in honour of the memory of the Blue Notes. There are 5 pictures with the article. The left picture shows Dudu Pukwana playing soprano saxophone, the top middle photo shows Johnny Dyani playing double bass, Mongezi Feza is on the below photo, Chris McGregor is on the top right picture and on the below right photo there is Harry Miller.
- Full Text:
- Date Issued: 1993
Foreign indirect investment platform
- ANC
- Authors: ANC
- Date: 1993
- Subjects: ANC
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/153901 , vital:39535
- Description: In the transition from apartheid to democracy, strong economic growth will be needed. This growth must succeed in overcoming the handicaps which apartheid imposed on South Africa. And it must bring higher living standards to the black majority, a reduction in absolute poverty levels, and a more equitable distribution of resources. The key to sustained and balanced economic growth is investment. Investment in productive capital must be greatly increased, and soon.
- Full Text:
- Date Issued: 1993
- Authors: ANC
- Date: 1993
- Subjects: ANC
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/153901 , vital:39535
- Description: In the transition from apartheid to democracy, strong economic growth will be needed. This growth must succeed in overcoming the handicaps which apartheid imposed on South Africa. And it must bring higher living standards to the black majority, a reduction in absolute poverty levels, and a more equitable distribution of resources. The key to sustained and balanced economic growth is investment. Investment in productive capital must be greatly increased, and soon.
- Full Text:
- Date Issued: 1993
The fishes of Tristan Da Cunha and Gough Island (South Atlantic), and the effects of environmental seasonality on the biology of selected species
- Authors: Andrew, Timothy Gilbert
- Date: 1993
- Subjects: Fishes -- Tristan da Cunha Fishes -- Gough Island Fishes -- Conservation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5284 , http://hdl.handle.net/10962/d1005128
- Description: This study focuses on the taxonomy, biogeography and biological aspects of the fishes of Tristan da Cunha and Gough Island in the cental South Atlantic Ocean. Oceanographic measurements were undertaken to determine the position and nature of the Subtropical Convergence (STC) in the vicinity of the islands. The Tristan da Cunha group is thought to be situated on the northern edge of the STC while Gough Island is situated on the southern edge of the front. The seasonal environmental cycle at the islands is characterised by an annual sea surface temperature fluctuation of approximately 5 °C and an annual change in stratification of the water column. It is suggested that this increase in stratification at the STC, brought about in the summer by insolation warming the surface layers of the ocean, enhances primary production. The STC is identified as a unique habitat for fishes and as an important barrier to dispersal of species in the Southern Ocean. The present study has produced 18 new distributional records from the shelf waters of Tristan da Cunha and Gough Island. The fish fauna known from the shelf waters of these islands is reviewed, and a diagnosis, synonymy, and in some cases an illustration are provided. For certain species, brief notes on their biology, relative abundance and seasonal distribution are included. An analysis of the ichthyofaunal relationships between shallow water areas in the vicinity of the STC has resulted in the identification of a characteristic neritic STC ichthyofauna. The circumglobal distribution of many of these species is thought to be a consequence of a dispersive pelagic phase in their life-cycles. Biological processes in fishes at these islands are temporally and spatially affected by seasonal changes in oceanographic conditions. Seasonal sea temperature variation was identified as being an indicator of other oceanographic phenomena that may affect processes such as growth, reproduction and feeding in fishes at the islands. Most species have a summer spawning season and growth rate increased during the summer months. It was hypothesised that enhanced primary production and a related increase in food quality and availability during the summer were the major factors temporally regulating the growth and reproduction of fishes at the islands. Twenty families of neritic fishes have been recorded in the shelf waters of Tristan da Cunhaand Gough Island. Most families are represented by only one species. Because of this a wide range of life-history strategies are apparent in the fauna. Nevertheless, there are a number of common life-history characteristics shared by most of the neritic species. Firstly, the early lifehistory of many species included an extended pelagic phase which might have facilitated colonisation throughout the STC zone in the past, thereby regulating extant species diversity in this region. Secondly, the common occurrence of an extended summer breeding season and iteroparity suggested that these characters also contributed to survival in what is considered to be an unpredictable environment. It would appear that these common characteristics hold the key to the success of many fishes in the STC zone. This study has contributed to our understanding of oceanic island ecosystems and has revealed distributional patterns of fishes that were unknown previously. By focusing on the biological processes of selected species the regulatory role played by local environmental conditions became apparent. The results of this study are also relevant to proposed conservation measures for Tristan da Cunha and Gough Island.
- Full Text:
- Date Issued: 1993
- Authors: Andrew, Timothy Gilbert
- Date: 1993
- Subjects: Fishes -- Tristan da Cunha Fishes -- Gough Island Fishes -- Conservation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5284 , http://hdl.handle.net/10962/d1005128
- Description: This study focuses on the taxonomy, biogeography and biological aspects of the fishes of Tristan da Cunha and Gough Island in the cental South Atlantic Ocean. Oceanographic measurements were undertaken to determine the position and nature of the Subtropical Convergence (STC) in the vicinity of the islands. The Tristan da Cunha group is thought to be situated on the northern edge of the STC while Gough Island is situated on the southern edge of the front. The seasonal environmental cycle at the islands is characterised by an annual sea surface temperature fluctuation of approximately 5 °C and an annual change in stratification of the water column. It is suggested that this increase in stratification at the STC, brought about in the summer by insolation warming the surface layers of the ocean, enhances primary production. The STC is identified as a unique habitat for fishes and as an important barrier to dispersal of species in the Southern Ocean. The present study has produced 18 new distributional records from the shelf waters of Tristan da Cunha and Gough Island. The fish fauna known from the shelf waters of these islands is reviewed, and a diagnosis, synonymy, and in some cases an illustration are provided. For certain species, brief notes on their biology, relative abundance and seasonal distribution are included. An analysis of the ichthyofaunal relationships between shallow water areas in the vicinity of the STC has resulted in the identification of a characteristic neritic STC ichthyofauna. The circumglobal distribution of many of these species is thought to be a consequence of a dispersive pelagic phase in their life-cycles. Biological processes in fishes at these islands are temporally and spatially affected by seasonal changes in oceanographic conditions. Seasonal sea temperature variation was identified as being an indicator of other oceanographic phenomena that may affect processes such as growth, reproduction and feeding in fishes at the islands. Most species have a summer spawning season and growth rate increased during the summer months. It was hypothesised that enhanced primary production and a related increase in food quality and availability during the summer were the major factors temporally regulating the growth and reproduction of fishes at the islands. Twenty families of neritic fishes have been recorded in the shelf waters of Tristan da Cunhaand Gough Island. Most families are represented by only one species. Because of this a wide range of life-history strategies are apparent in the fauna. Nevertheless, there are a number of common life-history characteristics shared by most of the neritic species. Firstly, the early lifehistory of many species included an extended pelagic phase which might have facilitated colonisation throughout the STC zone in the past, thereby regulating extant species diversity in this region. Secondly, the common occurrence of an extended summer breeding season and iteroparity suggested that these characters also contributed to survival in what is considered to be an unpredictable environment. It would appear that these common characteristics hold the key to the success of many fishes in the STC zone. This study has contributed to our understanding of oceanic island ecosystems and has revealed distributional patterns of fishes that were unknown previously. By focusing on the biological processes of selected species the regulatory role played by local environmental conditions became apparent. The results of this study are also relevant to proposed conservation measures for Tristan da Cunha and Gough Island.
- Full Text:
- Date Issued: 1993
Self-reports on the effectiveness of psychotherapy with therapists-in-training: an 18-month follow-up study at a psychology training clinic
- Authors: Angus, Catherine Clare
- Date: 1993
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193069 , vital:45295
- Description: The purpose of this study is to ascertain whether the clients who make use of the services of the Psychology Clinic at Rhodes University perceive the masters students being trained at the Clinic as providing adequate psychotherapy. Using a sample of 18 clients, who underwent psychotherapy at the Rhodes Psychology Clinic during 1990, a follow-up study was conducted to ascertain the perceived success of that psychotherapy. Those variables most pertinent to the outcome of psychotherapy are examined. The study uses both qualitative and quantitative methodology and shows that, overall, 89% of the clients who participated in this study perceived the psychotherapy at the Rhodes Psychology Clinic to be satisfactory. The study also highlights those factors which were perceived to be negative in the psychotherapeutic equation and it is hoped that the findings can be beneficial in planning more efficient services for the Clinic in the future. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
- Full Text:
- Date Issued: 1993
- Authors: Angus, Catherine Clare
- Date: 1993
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193069 , vital:45295
- Description: The purpose of this study is to ascertain whether the clients who make use of the services of the Psychology Clinic at Rhodes University perceive the masters students being trained at the Clinic as providing adequate psychotherapy. Using a sample of 18 clients, who underwent psychotherapy at the Rhodes Psychology Clinic during 1990, a follow-up study was conducted to ascertain the perceived success of that psychotherapy. Those variables most pertinent to the outcome of psychotherapy are examined. The study uses both qualitative and quantitative methodology and shows that, overall, 89% of the clients who participated in this study perceived the psychotherapy at the Rhodes Psychology Clinic to be satisfactory. The study also highlights those factors which were perceived to be negative in the psychotherapeutic equation and it is hoped that the findings can be beneficial in planning more efficient services for the Clinic in the future. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
- Full Text:
- Date Issued: 1993
"Why I like history ...": Ciskeian secondary school pupils' attitudes towards history
- Atuahene-Sarpong, Boateng Kofi
- Authors: Atuahene-Sarpong, Boateng Kofi
- Date: 1993
- Subjects: History -- Study and teaching (Secondary) -- South Africa--Ciskei -- Attitudes , History -- Study and teaching (Secondary) -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1824 , http://hdl.handle.net/10962/d1003710 , History -- Study and teaching (Secondary) -- South Africa--Ciskei -- Attitudes , History -- Study and teaching (Secondary) -- South Africa -- Ciskei
- Description: This dissertation was motivated by the decline in percentage of the number of Standard 10 pupils who offered History for the National Senior Certificate (Matriculation) Examination in the Mathole Directorate in the Ciskei from 1987 - 1990. The research revealed that the decrease in the number of pupils doing History in Standard 10 did not indicate loss of interest in the subject. Instead, the multiplicity of new subjects introduced in the school curriculum and some peculiar subject combinations in some schools forced some pupils (reluctantly) to reject History as a school subject. Those who chose to do History in Standard 10 showed their liking for the subject and expressed their interest in it. The study took the form of a survey through the use of questionnaire and informal chats with pupils and teachers on their views about History as a school subject. A questionnaire was designed for pupils offering History in Standard 10 and administered in four of the eight Senior Secondary Schools in the Mathole Directorate in Ciskei. Generally, work on pupils' interest in and attitude towards History as a school subject is very rare. Some of the few available works merely compare pupils' liking for History as opposed to other school subjects and when the response is not favourable; conclude that pupils in Senior Secondary Schools do not enjoy studying History. Pupils' interest in and attitudes towards the subject, the extent of their interest, the causes of their attitude and the internal and external influences on their interest in and attitudes towards the subject were neglected by earlier works, but have been given attention in this study. As a result of very little available work and material, pupils' responses to the questionnaire formed the basis of the material used in this work. A large number of pupils' responses was put in tables according to sex instead of schools. Where applicable, X2 tests were administered to see if there were any appreciable statistically significant differences between the responses of the boys and girls. In most cases where the X2 tests were applied, no statistically difference was noticed. The study showed more boys than girls showing interest in and positive attitudes towards History. The general picture of the study showed a deviation from the view commonly expressed by other studies that pupils in modern Senior Secondary Schools do not like History. As this study revealed, it is not the subject itself that pupils did not like, but the way it is handled by some teachers and lack of teaching aids to concretise events. This leads to the role of Teacher Training Institutions: which must be to produce the versatile, duty-conscious and innovating History teacher to revolutionise History teaching to make History alive to pupils.
- Full Text:
- Date Issued: 1993
- Authors: Atuahene-Sarpong, Boateng Kofi
- Date: 1993
- Subjects: History -- Study and teaching (Secondary) -- South Africa--Ciskei -- Attitudes , History -- Study and teaching (Secondary) -- South Africa -- Ciskei
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1824 , http://hdl.handle.net/10962/d1003710 , History -- Study and teaching (Secondary) -- South Africa--Ciskei -- Attitudes , History -- Study and teaching (Secondary) -- South Africa -- Ciskei
- Description: This dissertation was motivated by the decline in percentage of the number of Standard 10 pupils who offered History for the National Senior Certificate (Matriculation) Examination in the Mathole Directorate in the Ciskei from 1987 - 1990. The research revealed that the decrease in the number of pupils doing History in Standard 10 did not indicate loss of interest in the subject. Instead, the multiplicity of new subjects introduced in the school curriculum and some peculiar subject combinations in some schools forced some pupils (reluctantly) to reject History as a school subject. Those who chose to do History in Standard 10 showed their liking for the subject and expressed their interest in it. The study took the form of a survey through the use of questionnaire and informal chats with pupils and teachers on their views about History as a school subject. A questionnaire was designed for pupils offering History in Standard 10 and administered in four of the eight Senior Secondary Schools in the Mathole Directorate in Ciskei. Generally, work on pupils' interest in and attitude towards History as a school subject is very rare. Some of the few available works merely compare pupils' liking for History as opposed to other school subjects and when the response is not favourable; conclude that pupils in Senior Secondary Schools do not enjoy studying History. Pupils' interest in and attitudes towards the subject, the extent of their interest, the causes of their attitude and the internal and external influences on their interest in and attitudes towards the subject were neglected by earlier works, but have been given attention in this study. As a result of very little available work and material, pupils' responses to the questionnaire formed the basis of the material used in this work. A large number of pupils' responses was put in tables according to sex instead of schools. Where applicable, X2 tests were administered to see if there were any appreciable statistically significant differences between the responses of the boys and girls. In most cases where the X2 tests were applied, no statistically difference was noticed. The study showed more boys than girls showing interest in and positive attitudes towards History. The general picture of the study showed a deviation from the view commonly expressed by other studies that pupils in modern Senior Secondary Schools do not like History. As this study revealed, it is not the subject itself that pupils did not like, but the way it is handled by some teachers and lack of teaching aids to concretise events. This leads to the role of Teacher Training Institutions: which must be to produce the versatile, duty-conscious and innovating History teacher to revolutionise History teaching to make History alive to pupils.
- Full Text:
- Date Issued: 1993
Coastal dune ecology and management in the Eastern Cape
- Authors: Avis, Anthony Mark
- Date: 1993
- Subjects: Sand dune ecology -- South Africa Shore protection -- South Africa Coastal zone management -- South Africa Sand dunes -- South Africa Sand dune plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4185 , http://hdl.handle.net/10962/d1003753
- Description: The importance of understanding the ecological functioning of coastal dune systems is emphasized as being fundamental to the correct management of the dune landscape. Dune vegetation along the Eastern Cape coastline, from Cape St Francis in the west to Kei Mouth in the east was described in terms of the distribution and phytochorological affinities of the taxa. At a regional scale species distribution was strongly influenced by both the climate, particularly rainfall, and the phytochorological affinities of the taxa. Seven communities were defined using TWINSPAN, and the interrelationships between these communities in anyone area appeared to be linked to a successional gradient. Dune Slacks are thought to play a key role in this successional sequence, and a temporal study of this community led to a conceptual model of plant succession in these dunefields. Climate, particularly rainfall and wind, are major factors influencing plant succession. Wind-borne sand causes the slacks to migrate in an easterly direction under the influence of the predominantly westerly winds, although easterly winds, mainly in summer months may reverse these trends. Autogenic changes appeared to be important in this succession, and a comparative study of a good example of a primary succession at Mtunzini in Natal was undertaken to elucidate the main mechanism of change. Eight communities that were identified here were concluded to be distnbuted along a gradient of increasing age, with successional changes predictable, linear and directional. Species were grouped in distinct zones along the continuum and edaphic changes (decrease in soil pH, increase in organic matter and exchangeable bases) were related to the community based changes in species composition. The mechanism of change supported the facilitation model of plant succession which is a modification of the original Clementsian concept. Similar results were found in the Eastern Cape, but due to the harsh environment, multiple pathways of succession exist. Data from this study lent support to the model of plant succession developed earlier, and confinned that the dune slacks played an important role in this facilitation by acting as centres of diversity. The foredunes were found to have an indirect role in protecting these slacks from salt spray and sand movement. The central theme of the management studies was to investigate the ecological consequences of recreational pressure within the dune environment. Current levels of beach utilization at East London were lower than other beaches in South Africa, but a general trend of increasing utilization due to sociopolitical changes can be expected. The suitability of questionnaire surveys to assess aspects such as the adequacy of facilities, perceptual carrying capacity and the beach users opinion of natural vegetation and preference for particular beaches was demonstrated. The dune vegetation was found to be sensitive to human trampling, but at current levels, the ecological carrying capacity will not be exceeded since results of the aerial census counts and questionnaire survey revealed that few people entered sensitive zones such as the coastal forest. More detailed long term studies on the susceptibility of dune vegetation to both trampling and off-road vehicle impacts revealed a low resilience of dune plant communities to these effects. Although susceptibility differed between the three communities tested, generally the greatest amount of damage occurred after the first few passages, and vehicles caused a more significant decrease in height when compared to trampling. Recovery rates were slow and low levels of repeated damage were sufficient to retard or prevent the recovery of the plants. Stricter control of vehicle use on beaches is therefore required, and in high use zones the ecological carrying capacity should be increased by providing access tracks if possible, or if not possible, by restricting access. A historical account of the process of dune stabilization showed that although first initiated in 1845, indigenous species were only used in the past three decades. The use of alien species has resulted in problems such as a reduction in the ecological integrity and aesthetic appeal of coastal systems. The techniques applied in the stabilization of drift sands with indigenous vegetation have been successful, as revealed by a quantitative survey of 17 sites in the Eastern Cape. Sites were grouped by multivariate analysis on the basis of their species composition, and variability between sites was dependent on the types of species planted. Selection of suitable species is therefore important and is discussed with respect to their natural distribution along the coast. The long term objective of stabilization should be the creation of functional, diverse, aesthetic ecosystems, since the intrinsic and economic value of the dune landscape for tourism lies therein. However, detailed studies should be undertaken prior to implementing a manipulative process such as dune stabilization, since ecological processes may be disrupted. An understanding of such processes is therefore important if one wishes to effectively manage the dune landscape.
- Full Text:
- Date Issued: 1993
- Authors: Avis, Anthony Mark
- Date: 1993
- Subjects: Sand dune ecology -- South Africa Shore protection -- South Africa Coastal zone management -- South Africa Sand dunes -- South Africa Sand dune plants -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4185 , http://hdl.handle.net/10962/d1003753
- Description: The importance of understanding the ecological functioning of coastal dune systems is emphasized as being fundamental to the correct management of the dune landscape. Dune vegetation along the Eastern Cape coastline, from Cape St Francis in the west to Kei Mouth in the east was described in terms of the distribution and phytochorological affinities of the taxa. At a regional scale species distribution was strongly influenced by both the climate, particularly rainfall, and the phytochorological affinities of the taxa. Seven communities were defined using TWINSPAN, and the interrelationships between these communities in anyone area appeared to be linked to a successional gradient. Dune Slacks are thought to play a key role in this successional sequence, and a temporal study of this community led to a conceptual model of plant succession in these dunefields. Climate, particularly rainfall and wind, are major factors influencing plant succession. Wind-borne sand causes the slacks to migrate in an easterly direction under the influence of the predominantly westerly winds, although easterly winds, mainly in summer months may reverse these trends. Autogenic changes appeared to be important in this succession, and a comparative study of a good example of a primary succession at Mtunzini in Natal was undertaken to elucidate the main mechanism of change. Eight communities that were identified here were concluded to be distnbuted along a gradient of increasing age, with successional changes predictable, linear and directional. Species were grouped in distinct zones along the continuum and edaphic changes (decrease in soil pH, increase in organic matter and exchangeable bases) were related to the community based changes in species composition. The mechanism of change supported the facilitation model of plant succession which is a modification of the original Clementsian concept. Similar results were found in the Eastern Cape, but due to the harsh environment, multiple pathways of succession exist. Data from this study lent support to the model of plant succession developed earlier, and confinned that the dune slacks played an important role in this facilitation by acting as centres of diversity. The foredunes were found to have an indirect role in protecting these slacks from salt spray and sand movement. The central theme of the management studies was to investigate the ecological consequences of recreational pressure within the dune environment. Current levels of beach utilization at East London were lower than other beaches in South Africa, but a general trend of increasing utilization due to sociopolitical changes can be expected. The suitability of questionnaire surveys to assess aspects such as the adequacy of facilities, perceptual carrying capacity and the beach users opinion of natural vegetation and preference for particular beaches was demonstrated. The dune vegetation was found to be sensitive to human trampling, but at current levels, the ecological carrying capacity will not be exceeded since results of the aerial census counts and questionnaire survey revealed that few people entered sensitive zones such as the coastal forest. More detailed long term studies on the susceptibility of dune vegetation to both trampling and off-road vehicle impacts revealed a low resilience of dune plant communities to these effects. Although susceptibility differed between the three communities tested, generally the greatest amount of damage occurred after the first few passages, and vehicles caused a more significant decrease in height when compared to trampling. Recovery rates were slow and low levels of repeated damage were sufficient to retard or prevent the recovery of the plants. Stricter control of vehicle use on beaches is therefore required, and in high use zones the ecological carrying capacity should be increased by providing access tracks if possible, or if not possible, by restricting access. A historical account of the process of dune stabilization showed that although first initiated in 1845, indigenous species were only used in the past three decades. The use of alien species has resulted in problems such as a reduction in the ecological integrity and aesthetic appeal of coastal systems. The techniques applied in the stabilization of drift sands with indigenous vegetation have been successful, as revealed by a quantitative survey of 17 sites in the Eastern Cape. Sites were grouped by multivariate analysis on the basis of their species composition, and variability between sites was dependent on the types of species planted. Selection of suitable species is therefore important and is discussed with respect to their natural distribution along the coast. The long term objective of stabilization should be the creation of functional, diverse, aesthetic ecosystems, since the intrinsic and economic value of the dune landscape for tourism lies therein. However, detailed studies should be undertaken prior to implementing a manipulative process such as dune stabilization, since ecological processes may be disrupted. An understanding of such processes is therefore important if one wishes to effectively manage the dune landscape.
- Full Text:
- Date Issued: 1993
Epidemiological and aetiological aspects of diarrhoeal disease in the Eastern Cape
- Authors: Baxter, Esther
- Date: 1993
- Subjects: Diarrhea -- South Africa , Intestines -- Diseases , Pathogenic microorganisms -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4045 , http://hdl.handle.net/10962/d1004106 , Diarrhea -- South Africa , Intestines -- Diseases , Pathogenic microorganisms -- South Africa
- Description: Diarrhoeal disease is a major cause of mortality in children in developing countries. It also remains a serious problem among all age groups throughout the world. Whereas studies to determine the epidemiological and aetiological factors of diarrhoeal disease have been reported for other parts of South Africa and the world, as yet no information is available for the Eastern Cape. Therefore this study was undertaken to determine the factors for this area. Enteropathogens were compared for the different ages in the various population groups and, where possible, seasonal and geographical differences were emphasised. A total of 7 278 faecal samples were examined by six laboratories in the Eastern Cape during the period November 1988 to October 1990. Data was recorded noting the age, sex and population group of the patients. The towns selected were Port Elizabeth, Uitenhage, Cradock, Grahamstown and their surrounding areas. The isolation rates for the pathogens studied in the various population groups were compared to those reported in similar studies in other countries. The seasonal incidences of the various selected pathogens were compared with those reported from elsewhere in South Africa. It was thought that the higher temperature of summer may influence the finding in the White population group, while rainfall would play a greater role for the Coloured and Black populations. The geographical distribution of the pathogens emphasised the difference in living conditions between the different population groups. For example a generally higher infestation rate of Helminths occurred in rural areas and in the groups living under poorer conditions. The low isolation rates for certain bacteria and the large percentage of samples from which no pathogens were isolated indicate the need for further research. However, the finding should be valuable for determining Public Health priorities and in the management of outbreaks of diarrhoeal disease.
- Full Text:
- Date Issued: 1993
- Authors: Baxter, Esther
- Date: 1993
- Subjects: Diarrhea -- South Africa , Intestines -- Diseases , Pathogenic microorganisms -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4045 , http://hdl.handle.net/10962/d1004106 , Diarrhea -- South Africa , Intestines -- Diseases , Pathogenic microorganisms -- South Africa
- Description: Diarrhoeal disease is a major cause of mortality in children in developing countries. It also remains a serious problem among all age groups throughout the world. Whereas studies to determine the epidemiological and aetiological factors of diarrhoeal disease have been reported for other parts of South Africa and the world, as yet no information is available for the Eastern Cape. Therefore this study was undertaken to determine the factors for this area. Enteropathogens were compared for the different ages in the various population groups and, where possible, seasonal and geographical differences were emphasised. A total of 7 278 faecal samples were examined by six laboratories in the Eastern Cape during the period November 1988 to October 1990. Data was recorded noting the age, sex and population group of the patients. The towns selected were Port Elizabeth, Uitenhage, Cradock, Grahamstown and their surrounding areas. The isolation rates for the pathogens studied in the various population groups were compared to those reported in similar studies in other countries. The seasonal incidences of the various selected pathogens were compared with those reported from elsewhere in South Africa. It was thought that the higher temperature of summer may influence the finding in the White population group, while rainfall would play a greater role for the Coloured and Black populations. The geographical distribution of the pathogens emphasised the difference in living conditions between the different population groups. For example a generally higher infestation rate of Helminths occurred in rural areas and in the groups living under poorer conditions. The low isolation rates for certain bacteria and the large percentage of samples from which no pathogens were isolated indicate the need for further research. However, the finding should be valuable for determining Public Health priorities and in the management of outbreaks of diarrhoeal disease.
- Full Text:
- Date Issued: 1993
South African art institutions : their formation and strategy with particular reference to the question of legitimacy
- Authors: Becker, Carl
- Date: 1993
- Subjects: Art schools -- South Africa Art -- Study and teaching -- South Africa Art and society -- South Africa
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2456 , http://hdl.handle.net/10962/d1007622
- Description: I have examined the relationship between the art institution and its social base, and the way in which legitimacy is sought and maintained under changing social circumstances. The social pattern of 'avante garde artist' vs. 'philistine public' has tended to be the context within which 20th century art has developed. The consequent disjuncture between the public art institution and its social base was subsequently accepted as the natural condition of Fine Art production. During the 1980's, two significant factors were to influence this 'natural' condition: i) The demise of 'modernism' internationally, ' which broadened the scope of allowable objects for consideration as Fine Art. ii) Political mobilisation in South Africa was accompanied by calls for democratisation and charges of 'elitism' being levelled against many public institutions. These factors have combined to make the S.A. art institutions (public galleries, tertiary teaching institutions and national art competitions) re-assess their legitimacy, particularly in terms of 'accountability' and 'representativeness' . A close examination of these two factors is essential if one is to gain insight into the current condition of the public art institutions. This research is an attempt to understand the history and the current nature of the shifting relationship between the art institutions and the 'public' in South Africa. A further goal is to assess the extent to which concepts that are valid within the realm of the polity can be transposed into the cultural realm: A tendency prevalent within the cultural debate in South Africa during the 1980's. The emphasis of this mini thesis is on the artworld's perception of its social role. I therefore look at the way changing attitudes are reflected in the statements and writing of leading figures within this sector. The method is to critically analyse texts that pertain to my chosen area of research.
- Full Text:
- Date Issued: 1993
- Authors: Becker, Carl
- Date: 1993
- Subjects: Art schools -- South Africa Art -- Study and teaching -- South Africa Art and society -- South Africa
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2456 , http://hdl.handle.net/10962/d1007622
- Description: I have examined the relationship between the art institution and its social base, and the way in which legitimacy is sought and maintained under changing social circumstances. The social pattern of 'avante garde artist' vs. 'philistine public' has tended to be the context within which 20th century art has developed. The consequent disjuncture between the public art institution and its social base was subsequently accepted as the natural condition of Fine Art production. During the 1980's, two significant factors were to influence this 'natural' condition: i) The demise of 'modernism' internationally, ' which broadened the scope of allowable objects for consideration as Fine Art. ii) Political mobilisation in South Africa was accompanied by calls for democratisation and charges of 'elitism' being levelled against many public institutions. These factors have combined to make the S.A. art institutions (public galleries, tertiary teaching institutions and national art competitions) re-assess their legitimacy, particularly in terms of 'accountability' and 'representativeness' . A close examination of these two factors is essential if one is to gain insight into the current condition of the public art institutions. This research is an attempt to understand the history and the current nature of the shifting relationship between the art institutions and the 'public' in South Africa. A further goal is to assess the extent to which concepts that are valid within the realm of the polity can be transposed into the cultural realm: A tendency prevalent within the cultural debate in South Africa during the 1980's. The emphasis of this mini thesis is on the artworld's perception of its social role. I therefore look at the way changing attitudes are reflected in the statements and writing of leading figures within this sector. The method is to critically analyse texts that pertain to my chosen area of research.
- Full Text:
- Date Issued: 1993
Ecological correlates of relative brain size in some South African rodents
- Bernard, Ric T F, Nurton, Jane P
- Authors: Bernard, Ric T F , Nurton, Jane P
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447245 , vital:74599 , https://www.ajol.info/index.php/az/article/view/154234
- Description: Relative brain size (size of the brain once body size effects have been removed) has been calculated for 16 species of rodent from South Africa and is shown to vary with six species having a positive RBS (that is a brain larger than expected) and 10 a negative RBS. Arboreal species such as Paraxerus cepapi and Graphiurus murinus and omnivores (G. murinus) have relatively larger brains than do the fossoriai root eaters such as Cryptomys hottentotus and terrestrial follivores (Otomys irroratus). It is suggested that the relatively large brains can be linked to the complex behavioural patterns necessary for locomotion in three dimensions and for utilization of a food resource such as insects that is randomly distributed in time and space. The three sciuromorph rodents (Xerus inauris, Paraxerus cepapi and Pedetes capensis) have very different life styles but all have a positive RBS and it is suggested that a relatively large brain may be a characteristic of the suborder.
- Full Text:
- Date Issued: 1993
- Authors: Bernard, Ric T F , Nurton, Jane P
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447245 , vital:74599 , https://www.ajol.info/index.php/az/article/view/154234
- Description: Relative brain size (size of the brain once body size effects have been removed) has been calculated for 16 species of rodent from South Africa and is shown to vary with six species having a positive RBS (that is a brain larger than expected) and 10 a negative RBS. Arboreal species such as Paraxerus cepapi and Graphiurus murinus and omnivores (G. murinus) have relatively larger brains than do the fossoriai root eaters such as Cryptomys hottentotus and terrestrial follivores (Otomys irroratus). It is suggested that the relatively large brains can be linked to the complex behavioural patterns necessary for locomotion in three dimensions and for utilization of a food resource such as insects that is randomly distributed in time and space. The three sciuromorph rodents (Xerus inauris, Paraxerus cepapi and Pedetes capensis) have very different life styles but all have a positive RBS and it is suggested that a relatively large brain may be a characteristic of the suborder.
- Full Text:
- Date Issued: 1993
Seasonal changes in pituitary and plasma prolactin concentrations, and the role of Prolactin in the control of delayed implantation in female Miniopterus schreibersii
- Authors: Bojarski, Christina
- Date: 1993
- Subjects: Bats -- Reproduction Prolactin -- Research Pituitary hormones Zoology, Experimental
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5764 , http://hdl.handle.net/10962/d1005452
- Description: Mammotropes were successfully identified in the anterior pituitary gland of Miniopterus schreibersii using immunocytochemical (ICC) staining at the light and electron microscopy level. Mammotropes were distributed throughout the gland, were polygonal in shape and during secretory activity contained numerous large secretory granules (350 - 800nm). Using double ICC labelling, prolactin and growth hormone were never co-localiszed and found in individual cells only. Plasma prolactin levels were successfully measured on a monthly basis using radioimmunoassay and monthly pituitary prolactin levels were quantified using morphometric analysis of immunogold ICC staining and densitometry with polyacrylamide gels. Seasonal changes in the ultrastructure of mammotropes, and pituitary and plasma prolactin concentrations in female Miniopterus schreibersii indicated that there was an increase in prolactin secretion during the second half of the period of delayed implantation and that prolactin secretion remained elevated during normal embryonic development and lactation. This suggests that prolactin may be part of the luteotropic and lactogenic complex, and that the hormone might be responsible for terminating the period of delayed implantation. The latter is supported by experiments, where exogenous prolactin initiated precocious implantation during early delayed implantation, and treatment with bromocryptine (which inhibits prolactin synthesis) retarded implantation. Activation of mammotropes to synthesise prolactin and an increase of plasma prolactin levels occurred shortly after the winter solstice (21 June), suggesting that increasing daylength may be the environmental cue, which terminates the period of delayed implantation in Miniopterus schreibersii.
- Full Text:
- Date Issued: 1993
- Authors: Bojarski, Christina
- Date: 1993
- Subjects: Bats -- Reproduction Prolactin -- Research Pituitary hormones Zoology, Experimental
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5764 , http://hdl.handle.net/10962/d1005452
- Description: Mammotropes were successfully identified in the anterior pituitary gland of Miniopterus schreibersii using immunocytochemical (ICC) staining at the light and electron microscopy level. Mammotropes were distributed throughout the gland, were polygonal in shape and during secretory activity contained numerous large secretory granules (350 - 800nm). Using double ICC labelling, prolactin and growth hormone were never co-localiszed and found in individual cells only. Plasma prolactin levels were successfully measured on a monthly basis using radioimmunoassay and monthly pituitary prolactin levels were quantified using morphometric analysis of immunogold ICC staining and densitometry with polyacrylamide gels. Seasonal changes in the ultrastructure of mammotropes, and pituitary and plasma prolactin concentrations in female Miniopterus schreibersii indicated that there was an increase in prolactin secretion during the second half of the period of delayed implantation and that prolactin secretion remained elevated during normal embryonic development and lactation. This suggests that prolactin may be part of the luteotropic and lactogenic complex, and that the hormone might be responsible for terminating the period of delayed implantation. The latter is supported by experiments, where exogenous prolactin initiated precocious implantation during early delayed implantation, and treatment with bromocryptine (which inhibits prolactin synthesis) retarded implantation. Activation of mammotropes to synthesise prolactin and an increase of plasma prolactin levels occurred shortly after the winter solstice (21 June), suggesting that increasing daylength may be the environmental cue, which terminates the period of delayed implantation in Miniopterus schreibersii.
- Full Text:
- Date Issued: 1993
Sarcasm, conflict and style in Mtywaku's plays
- Authors: Bokwe, Goliath Dumezweni
- Date: 1993
- Subjects: Xhosa drama -- History and criticism , Xhosa language -- Terms and phrases , Drama -- Black authors -- History and criticism , Playwriting
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3594 , http://hdl.handle.net/10962/d1002169 , Xhosa drama -- History and criticism , Xhosa language -- Terms and phrases , Drama -- Black authors -- History and criticism , Playwriting
- Description: The following main aspects of Mtywaku's plays have been dealt with in the dissertation: (i) Sarcasm (ii) Conflict (iii) Style.
- Full Text:
- Date Issued: 1993
- Authors: Bokwe, Goliath Dumezweni
- Date: 1993
- Subjects: Xhosa drama -- History and criticism , Xhosa language -- Terms and phrases , Drama -- Black authors -- History and criticism , Playwriting
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3594 , http://hdl.handle.net/10962/d1002169 , Xhosa drama -- History and criticism , Xhosa language -- Terms and phrases , Drama -- Black authors -- History and criticism , Playwriting
- Description: The following main aspects of Mtywaku's plays have been dealt with in the dissertation: (i) Sarcasm (ii) Conflict (iii) Style.
- Full Text:
- Date Issued: 1993
The ultrastructure and computer-enhanced digital image analysis of plasmodesmata at the Kranz mesophyll-bundle sheath interface of Themeda triandra var. imberbis (Retz) A. Camus in conventionally-fixed leaf blades
- Botha, Christiaan E J, Hartley, B J, Cross, Robin H M
- Authors: Botha, Christiaan E J , Hartley, B J , Cross, Robin H M
- Date: 1993
- Language: English
- Type: Article
- Identifier: vital:6502 , http://hdl.handle.net/10962/d1005925
- Description: The ultrastructure of the plasmodesmata at the Kranz mesophyll-bundle sheath (KMS-BS) interface in Themeda triandra, and the substructures within the plasmodesmata were investigated, using conventionally fixed leaf-blade material, enhanced by the addition of 0.1% tannic acid to the primary fixative. Examination of high-resolution electronmicrographs, and computer-enhanced digital images suggests that these plasmodesmata are complex structures, comprised of helically-arranged particulate material. The electron-dense particles are between 2.5 and 3.0nm in diameter. These particles are specifically associated with the inner face of the inner plasmalemma membrane leaflet, and the outer region of the desmotubule wall. The electron-dense particles are presumably proteinaceous and embedded in a lipid matrix. In the constricted median portion of the KMS-BS plasmodesmata, the space between the desmotubule and the inner plasmalemma membrane leaflet and areas surrounding the proteinaceous particles thereof (the cytoplasmic sleeve) is about 3nm in cross-section, and constitutes what we believe to be the space through which intercellular transport takes place.
- Full Text: false
- Date Issued: 1993
- Authors: Botha, Christiaan E J , Hartley, B J , Cross, Robin H M
- Date: 1993
- Language: English
- Type: Article
- Identifier: vital:6502 , http://hdl.handle.net/10962/d1005925
- Description: The ultrastructure of the plasmodesmata at the Kranz mesophyll-bundle sheath (KMS-BS) interface in Themeda triandra, and the substructures within the plasmodesmata were investigated, using conventionally fixed leaf-blade material, enhanced by the addition of 0.1% tannic acid to the primary fixative. Examination of high-resolution electronmicrographs, and computer-enhanced digital images suggests that these plasmodesmata are complex structures, comprised of helically-arranged particulate material. The electron-dense particles are between 2.5 and 3.0nm in diameter. These particles are specifically associated with the inner face of the inner plasmalemma membrane leaflet, and the outer region of the desmotubule wall. The electron-dense particles are presumably proteinaceous and embedded in a lipid matrix. In the constricted median portion of the KMS-BS plasmodesmata, the space between the desmotubule and the inner plasmalemma membrane leaflet and areas surrounding the proteinaceous particles thereof (the cytoplasmic sleeve) is about 3nm in cross-section, and constitutes what we believe to be the space through which intercellular transport takes place.
- Full Text: false
- Date Issued: 1993
Bioaccumulation of metal cations by yeast and yeast cell components
- Authors: Brady, Dean
- Date: 1993
- Subjects: Yeast , Yeast fungi -- Biotechnology , Cations , Metal ions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4046 , http://hdl.handle.net/10962/d1004107 , Yeast , Yeast fungi -- Biotechnology , Cations , Metal ions
- Description: The aim of the project was to determine whether a by-product of industrial fermentations, Saccharomyces cerevisiae, could be utilized to bioaccumulate heavy metal cations and to partially define the mechanism of accumulation. S. cerevisiae cells were found to be capable of accumulating Cu²⁺in a manner that was proportional to the external Cu²⁺ concentration and inversely proportional to the concentration of biomass. The accumulation process was only minimally affected by temperature variations between 5 and 40°C or high ambient concentrations of sodium chloride. The accumulation process was however considerably affected by variations in pH, bioaccumulation being most efficient at pH 5 - 9 but becoming rapidly less so at either extreme of pH. Selection for copper resistant or tolerant yeast diminished the yeast's capacity for Cu²⁺ accumulation. For this and other reasons the development of heavy metal tolerance in yeasts was deemed to be generally counterproductive to heavy metal bioaccumulation. The yeast biomass was also capable of accumulating other heavy metal cations such as c0²⁺ or Cd²⁺. The yeast biomass could be harvested after bioaccumulation by tangential filtration methods, or alternatively could be packed into hollow fibre microfilter membrane cartridges and used as a fixed-bed bioaccumulator. By immobilizing the yeast in polyacrylamide gel and packing this material into columns, cu²⁺, C0²⁺ or Cd²⁺ could be removed from influent aqueous solutions yielding effluents with no detectable heavy metal, until breakthrough point was reached. This capacity was hypothesized to be a function of numerous "theoretical plates of equilibrium" within the column. The immobilized biomass could be eluted with EDTA and recycled for further bioaccumulation processes with minor loss of bioaccumulation capacity. Yeast cells were fractionated to permit identification of the major cell fractions and molecular components responsible for metal binding. Isolation of the yeast cell walls permitted investigation of their role in heavy metal accumulation. Although the amino groups of chitosan and proteins, the carboxyl groups of proteins, and the phosphate groups of phosphomannans were found to be efficient groups for the accumulation of copper, the less effective hydroxyl groups of the carbohydrate polymers (glucans and mannans) had a similar overall capacity for copper accumulation owing to their predominance in the yeast cell wall. The outer (protein-mannan) layer of the yeast cell wall was found to be a better Cu²⁺ chelator than the inner (chitinglucan) layer. It appeared that the physical condition of the cell wall may be more important than the individual macromolecular components of the cell wall in metal accumulation. It was apparent that the cell wall was the major, if not the sole contributor to heavy metal accumulation at low ambient heavy metal concentrations. At higher ambient metal concentrations the cytosol and vacuole become involved in bioaccumulation. Copper and other metals caused rapid loss of 70% of the intracellular potassium, implying permeation of the plasma membrane. This was followed by a slower "leakage" of magnesium from the vacuole which paralleled Cu²⁺ accumulation, suggesting that it may represent some form of ion-exchange. An intracellular copper chelating agent of approximately 2 kDalton molecular mass was isolated from copper tolerant yeast. This chelator was not a metallothionein and bound relatively low molar equivalents of copper compared to those reported for metallothionein. Treatment of the biomass with hot alkali yielded two biosorbents, one soluble (which could be used as a heavy metal flocculent), and an insoluble biosorbent which could be formed into a granular product to be used in fixed-bed biosorption columns. The granular biosorbent could accumulate a wide range of heavy metal cations in a semispecific manner and could be stored in a dehydrated form indefinitely, and rehydrated when required. Bioaccumulation by live algae was investigated as an alternative to yeast based processes. Various strains of algae, of which Scenedesmus and Selenastrum were the most effective, were found to be capable of accumulating heavy metals such as Cu²⁺, Pb²⁺ and Cr³⁺.
- Full Text:
- Date Issued: 1993
- Authors: Brady, Dean
- Date: 1993
- Subjects: Yeast , Yeast fungi -- Biotechnology , Cations , Metal ions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4046 , http://hdl.handle.net/10962/d1004107 , Yeast , Yeast fungi -- Biotechnology , Cations , Metal ions
- Description: The aim of the project was to determine whether a by-product of industrial fermentations, Saccharomyces cerevisiae, could be utilized to bioaccumulate heavy metal cations and to partially define the mechanism of accumulation. S. cerevisiae cells were found to be capable of accumulating Cu²⁺in a manner that was proportional to the external Cu²⁺ concentration and inversely proportional to the concentration of biomass. The accumulation process was only minimally affected by temperature variations between 5 and 40°C or high ambient concentrations of sodium chloride. The accumulation process was however considerably affected by variations in pH, bioaccumulation being most efficient at pH 5 - 9 but becoming rapidly less so at either extreme of pH. Selection for copper resistant or tolerant yeast diminished the yeast's capacity for Cu²⁺ accumulation. For this and other reasons the development of heavy metal tolerance in yeasts was deemed to be generally counterproductive to heavy metal bioaccumulation. The yeast biomass was also capable of accumulating other heavy metal cations such as c0²⁺ or Cd²⁺. The yeast biomass could be harvested after bioaccumulation by tangential filtration methods, or alternatively could be packed into hollow fibre microfilter membrane cartridges and used as a fixed-bed bioaccumulator. By immobilizing the yeast in polyacrylamide gel and packing this material into columns, cu²⁺, C0²⁺ or Cd²⁺ could be removed from influent aqueous solutions yielding effluents with no detectable heavy metal, until breakthrough point was reached. This capacity was hypothesized to be a function of numerous "theoretical plates of equilibrium" within the column. The immobilized biomass could be eluted with EDTA and recycled for further bioaccumulation processes with minor loss of bioaccumulation capacity. Yeast cells were fractionated to permit identification of the major cell fractions and molecular components responsible for metal binding. Isolation of the yeast cell walls permitted investigation of their role in heavy metal accumulation. Although the amino groups of chitosan and proteins, the carboxyl groups of proteins, and the phosphate groups of phosphomannans were found to be efficient groups for the accumulation of copper, the less effective hydroxyl groups of the carbohydrate polymers (glucans and mannans) had a similar overall capacity for copper accumulation owing to their predominance in the yeast cell wall. The outer (protein-mannan) layer of the yeast cell wall was found to be a better Cu²⁺ chelator than the inner (chitinglucan) layer. It appeared that the physical condition of the cell wall may be more important than the individual macromolecular components of the cell wall in metal accumulation. It was apparent that the cell wall was the major, if not the sole contributor to heavy metal accumulation at low ambient heavy metal concentrations. At higher ambient metal concentrations the cytosol and vacuole become involved in bioaccumulation. Copper and other metals caused rapid loss of 70% of the intracellular potassium, implying permeation of the plasma membrane. This was followed by a slower "leakage" of magnesium from the vacuole which paralleled Cu²⁺ accumulation, suggesting that it may represent some form of ion-exchange. An intracellular copper chelating agent of approximately 2 kDalton molecular mass was isolated from copper tolerant yeast. This chelator was not a metallothionein and bound relatively low molar equivalents of copper compared to those reported for metallothionein. Treatment of the biomass with hot alkali yielded two biosorbents, one soluble (which could be used as a heavy metal flocculent), and an insoluble biosorbent which could be formed into a granular product to be used in fixed-bed biosorption columns. The granular biosorbent could accumulate a wide range of heavy metal cations in a semispecific manner and could be stored in a dehydrated form indefinitely, and rehydrated when required. Bioaccumulation by live algae was investigated as an alternative to yeast based processes. Various strains of algae, of which Scenedesmus and Selenastrum were the most effective, were found to be capable of accumulating heavy metals such as Cu²⁺, Pb²⁺ and Cr³⁺.
- Full Text:
- Date Issued: 1993
The deaths of Cordelia and Lear
- Authors: Butler, Guy F
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457881 , vital:75687 , https://hdl.handle.net/10520/AJA1011582X_33
- Description:
- Full Text:
- Date Issued: 1993
- Authors: Butler, Guy F
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457881 , vital:75687 , https://hdl.handle.net/10520/AJA1011582X_33
- Description:
- Full Text:
- Date Issued: 1993
A comparative study of the life histories of the sister species, Pseudobarbus afer and Pseudobarbus asper, in the Gamtoos River system, South Africa
- Authors: Cambray, James Alfred
- Date: 1993
- Subjects: Barbus -- Life cycles , Barbus -- Ecology -- South Africa -- Gamtoos River , Cyprinidae -- Life cycles , Cyprinidae -- Ecology -- South Africa -- Gamtoos River , Minnows -- Life cycles , Minnows -- Ecology -- South Africa -- Gamtoos River
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5375 , http://hdl.handle.net/10962/d1015730
- Description: This thesis explores the biology, ecology, and life-history styles of two closely-related redfin minnows, Pseudobarbus afer and P. asper (pisces; Cyprinidae), which both occur in the Gamtoos River system of South Africa. Five of the seven species of flexible-rayed redfin minnows are in the South African Red Data Book - Fishes. This investigation was designed to provide the data which would enable conservation authorities to manage the remaining populations of the Pseudobarbus species. A thorough understanding of the Gamtoos River system was necessary to properly interpret the findings of this study. The palaeo river systems and the changing climates since the break-up of Gondwanaland are discussed so that the present day environments could be considered as well as the past environmental changes. P. afer and P. asper occur in the Gamtoos River system with no physical barrier separating the two species. P. afer only occurs in the clear mountain streams of the Cape Fold Mountain Belt whereas P. asper occurs in the highly saline and turbid Karoo section of the system. P. afer were found to be the more precocial form of the sister species. They had bigger eggs, lower relative fecundity, shorter breeding season, lower gonadosomatic indices, larger first feeding larval fish, matured later and had a longer life-span than did P. asper, which had more altricial life-history attributes. They differ in their tradeoffs with P. asper devoting more resources earlier to reproduction and having a shorter lifespan. The improvement in the one aspect of fitness (early maturity) leads to the deterioration in another, namely lifespan. Both species undertake breeding migrations to riffle areas where they spawn in mid-channel immediately above a pool after an increase in water flow. P. afer and P. asper are non-guarders of their non-adhesive eggs and young, open substrate spawners on coarse substrates (rocks) and have photophobic free embryos. The breeding season is shorter for P. afer whereas P. asper can spawn as late as April and impoundment releases can induce them to spawn. A study of comparative neuroecology revealed that of the four groups of fish analyzed (males and females of both species) male P. afer had the largest brains, especially the optic lobes and cerebellum. P. asper females had the smallest brains. No neural compensation in the external gustatory centre, the facial lobe, was found for P. asper inhabiting the turbid waters. P. afer also had significantly larger eyes and longer barbels. P. afer males were also found to have the highest density and largest nuptial tubercles as well as the most pronounced breeding colouration. It was concluded that P. asper is the more derived of the sister species pair with regard to life-history attributes. It is further suggested that investment per offspring is important in determining the life-history trajectories. Paedomorphosis has occurred and by this mechanism variability has been restored to the redfin minnows in the Groot River which enables them to survive in the highly variable, intermittent Karoo stream. The more precocial P. afer do not require this variability in the more constant and predictable environment of the Wit River.
- Full Text:
- Date Issued: 1993
- Authors: Cambray, James Alfred
- Date: 1993
- Subjects: Barbus -- Life cycles , Barbus -- Ecology -- South Africa -- Gamtoos River , Cyprinidae -- Life cycles , Cyprinidae -- Ecology -- South Africa -- Gamtoos River , Minnows -- Life cycles , Minnows -- Ecology -- South Africa -- Gamtoos River
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5375 , http://hdl.handle.net/10962/d1015730
- Description: This thesis explores the biology, ecology, and life-history styles of two closely-related redfin minnows, Pseudobarbus afer and P. asper (pisces; Cyprinidae), which both occur in the Gamtoos River system of South Africa. Five of the seven species of flexible-rayed redfin minnows are in the South African Red Data Book - Fishes. This investigation was designed to provide the data which would enable conservation authorities to manage the remaining populations of the Pseudobarbus species. A thorough understanding of the Gamtoos River system was necessary to properly interpret the findings of this study. The palaeo river systems and the changing climates since the break-up of Gondwanaland are discussed so that the present day environments could be considered as well as the past environmental changes. P. afer and P. asper occur in the Gamtoos River system with no physical barrier separating the two species. P. afer only occurs in the clear mountain streams of the Cape Fold Mountain Belt whereas P. asper occurs in the highly saline and turbid Karoo section of the system. P. afer were found to be the more precocial form of the sister species. They had bigger eggs, lower relative fecundity, shorter breeding season, lower gonadosomatic indices, larger first feeding larval fish, matured later and had a longer life-span than did P. asper, which had more altricial life-history attributes. They differ in their tradeoffs with P. asper devoting more resources earlier to reproduction and having a shorter lifespan. The improvement in the one aspect of fitness (early maturity) leads to the deterioration in another, namely lifespan. Both species undertake breeding migrations to riffle areas where they spawn in mid-channel immediately above a pool after an increase in water flow. P. afer and P. asper are non-guarders of their non-adhesive eggs and young, open substrate spawners on coarse substrates (rocks) and have photophobic free embryos. The breeding season is shorter for P. afer whereas P. asper can spawn as late as April and impoundment releases can induce them to spawn. A study of comparative neuroecology revealed that of the four groups of fish analyzed (males and females of both species) male P. afer had the largest brains, especially the optic lobes and cerebellum. P. asper females had the smallest brains. No neural compensation in the external gustatory centre, the facial lobe, was found for P. asper inhabiting the turbid waters. P. afer also had significantly larger eyes and longer barbels. P. afer males were also found to have the highest density and largest nuptial tubercles as well as the most pronounced breeding colouration. It was concluded that P. asper is the more derived of the sister species pair with regard to life-history attributes. It is further suggested that investment per offspring is important in determining the life-history trajectories. Paedomorphosis has occurred and by this mechanism variability has been restored to the redfin minnows in the Groot River which enables them to survive in the highly variable, intermittent Karoo stream. The more precocial P. afer do not require this variability in the more constant and predictable environment of the Wit River.
- Full Text:
- Date Issued: 1993
CWIU Congress resolutions 1993 - Draft
- Chemical Workers Industrial Union (CWIU)
- Authors: Chemical Workers Industrial Union (CWIU)
- Date: 1993
- Subjects: CWIU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/170159 , vital:41863
- Description: The CWIU recognises the need to develop a long term organisational vision, develop and implement creative and effective strategies, prioritise campaigns/activities in order to be able to sustain these, adapt and change by a process of restructuring, deal effectively with political and economic issues. Development of a long term Vision Congress reaffirms our objective of a socialist future Our programmes must therefore reflect this vision. The trade union movement as a working class organisation has a major role in any socialist programme. The labour movement must remain independent. This independence must not be compromised. Overall strategy for trade union movement The current direction of Cosatu towards so called "Strategic Unionism" must be thoroughly discussed. A progamme of discussion on this must be implemented in the Union. We confirm our belief in the following principles and any strategy must be based on these: worker control, accountability of leadership a combination of negotiations,mass action and struggle as the means to achieve our goals/demands.
- Full Text:
- Date Issued: 1993
- Authors: Chemical Workers Industrial Union (CWIU)
- Date: 1993
- Subjects: CWIU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/170159 , vital:41863
- Description: The CWIU recognises the need to develop a long term organisational vision, develop and implement creative and effective strategies, prioritise campaigns/activities in order to be able to sustain these, adapt and change by a process of restructuring, deal effectively with political and economic issues. Development of a long term Vision Congress reaffirms our objective of a socialist future Our programmes must therefore reflect this vision. The trade union movement as a working class organisation has a major role in any socialist programme. The labour movement must remain independent. This independence must not be compromised. Overall strategy for trade union movement The current direction of Cosatu towards so called "Strategic Unionism" must be thoroughly discussed. A progamme of discussion on this must be implemented in the Union. We confirm our belief in the following principles and any strategy must be based on these: worker control, accountability of leadership a combination of negotiations,mass action and struggle as the means to achieve our goals/demands.
- Full Text:
- Date Issued: 1993
A critical analysis of the examining of poetry in the English First Language Higher Grade course at senior secondary level in Cape Education Department schools
- Authors: Clarke, Linda Colleen
- Date: 1993
- Subjects: Examinations -- South Africa -- Evaluation English poetry -- Examinations English poetry -- Study and teaching (Secondary -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1473 , http://hdl.handle.net/10962/d1003354
- Description: The study of poetry has become entrenched in most secondary school English syllabuses, including the English First Language Higher Grade syllabus of the Cape Education Department. This acceptance of poetry as a part of the formal academic programme has, however, been accompanied by a demand that could be considered contrary to the spirit of poetry: that an examination should conclude the study. The problem is exacerbated if this examination is set and controlled by an external body, since the nature and objectives of a standardised, mass examination frequently conflict sharply with the aims of studying poetry. The implications of such control over the examining of poetry go beyond this, however. These include the defining and narrowing of the course of study by means of lists of prescribed poems selected by a committee often far removed from the world of the candidates and the significant combined effect of these lists and the style of questioning adopted by the external examiners on methods of teaching. Furthermore, the influence of the external examination is not restricted to the final year of study; the approach to poetry during the entire senior secondary course (of three years) tends to conform to the pattern laid down by the final examination paper. This domination of the external examination over the study of poetry is acknowledged but not condoned. There is undoubtedly a need for further research into alternative ways of assessing a poetry course. In the face of reality, however, this study seeks to identify and analyse the many features of external control that influence the study of poetry; and to consider ways in which examinations in poetry can be devised, approached and used to the best effect in order to fulfil the aims of studying poetry. The most important of these aims are held to be the pleasure and enjoyment of personal engagement with a poem, where there is a meeting of minds, a generation and deepening of emotion and feeling, extension of awareness and stimulation of imagination.
- Full Text: false
- Date Issued: 1993
- Authors: Clarke, Linda Colleen
- Date: 1993
- Subjects: Examinations -- South Africa -- Evaluation English poetry -- Examinations English poetry -- Study and teaching (Secondary -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1473 , http://hdl.handle.net/10962/d1003354
- Description: The study of poetry has become entrenched in most secondary school English syllabuses, including the English First Language Higher Grade syllabus of the Cape Education Department. This acceptance of poetry as a part of the formal academic programme has, however, been accompanied by a demand that could be considered contrary to the spirit of poetry: that an examination should conclude the study. The problem is exacerbated if this examination is set and controlled by an external body, since the nature and objectives of a standardised, mass examination frequently conflict sharply with the aims of studying poetry. The implications of such control over the examining of poetry go beyond this, however. These include the defining and narrowing of the course of study by means of lists of prescribed poems selected by a committee often far removed from the world of the candidates and the significant combined effect of these lists and the style of questioning adopted by the external examiners on methods of teaching. Furthermore, the influence of the external examination is not restricted to the final year of study; the approach to poetry during the entire senior secondary course (of three years) tends to conform to the pattern laid down by the final examination paper. This domination of the external examination over the study of poetry is acknowledged but not condoned. There is undoubtedly a need for further research into alternative ways of assessing a poetry course. In the face of reality, however, this study seeks to identify and analyse the many features of external control that influence the study of poetry; and to consider ways in which examinations in poetry can be devised, approached and used to the best effect in order to fulfil the aims of studying poetry. The most important of these aims are held to be the pleasure and enjoyment of personal engagement with a poem, where there is a meeting of minds, a generation and deepening of emotion and feeling, extension of awareness and stimulation of imagination.
- Full Text: false
- Date Issued: 1993