Removal of copper and nickel from solution by the non-viable biomass of the water fern Azolla filiculoides in an upscaled fixed-bed column system
- Authors: Thompson, Denis Alan
- Date: 2001
- Subjects: Copper , Nickel , Azolla , Heavy metals -- Absorption and adsorption
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3914 , http://hdl.handle.net/10962/d1003973 , Copper , Nickel , Azolla , Heavy metals -- Absorption and adsorption
- Description: The potential of non-viable Azalia filiculaides for the removal of Cu and Ni from aqueous solutions and the possibility of scaling up existing lab scale Azalia column systems was investigated. The effects of factors such as metal starting concentration, pH and two metals in solution on the removal of Ni and Cu from aqueous solution by dried and crushed Azalia biomass were studied in batch systems. Aqueous solutions of Ni with starting concentrations between 1000 and 2000J.lmolll gave the most efficient Ni removal by Azalla biomass. For Cu the optimum starting concentration for adsorption was 50J.lmol/l. The adsorption capacity of both eu and Ni increased as the starting pH of the sorption media increased. The optimum pH for Ni adsorption was found at pH 7 and for Cu, at pH 5. - Awlla biomass had a higher. maximum binding capacity (qrnax) for Cu than for Ni at pH 5. The removal of both Cu allct Ni showed little or no variation with the presence another metal in solution. Kinetic studies show that both Cu and Ni adsorbed rapidly onto the Azalia biomass. The removal of Cu and Ni from aqueous solutions using non-viable Azalia biomass was investigated in a lab scale fixed-bed column and an upscaled 4L column system. The nonviable Azalla filiculaides biomass when dried and used in a column for adsorption of Cu and Ni showed good physical stability under many different conditions. Preparation of the biomass before it could be used in the columns was very simple and did not involve any significant pretreatment steps. Prolonged exposure to UV light decreases Azalia biomass capacity for Ni and Cu adsorption. Column adsorption of Cu and Ni from aqueous solutions was successfully upscaled approximately 100 times. Relative to the lab scale column, the 4L column performed better for the uptake of Cu and Ni per gram of biomass. The larger column was also able to operate at relatively higher flow rates. The biomass showed good reusability with little change in the amount of Ni adsorbed in 10 consecutive cycles. Electron micrographs showecf little or no change in the physical structure and integrity of the Azolla biomass after exposure to mineral acids, Ni solution and high flow rates over 10 consecutive adsorption and desorption cycles. As much as 80% Ni and 70 % Cu was recovered when desorption profiles were generated using O.lMHCI as a desorption agent. The 4L column system was also tested using a highly concen~rat:~ Ni plating bath solution.(Nicrolyte 1). Only 18 % of the Ni could be removed from the expended Nicrolyte 1 pla~Jng solution after treating only 25L, indicating that Azolla biomass is more suited for removal of metals from more dilute industrial effluents.
- Full Text:
- Date Issued: 2001
- Authors: Thompson, Denis Alan
- Date: 2001
- Subjects: Copper , Nickel , Azolla , Heavy metals -- Absorption and adsorption
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3914 , http://hdl.handle.net/10962/d1003973 , Copper , Nickel , Azolla , Heavy metals -- Absorption and adsorption
- Description: The potential of non-viable Azalia filiculaides for the removal of Cu and Ni from aqueous solutions and the possibility of scaling up existing lab scale Azalia column systems was investigated. The effects of factors such as metal starting concentration, pH and two metals in solution on the removal of Ni and Cu from aqueous solution by dried and crushed Azalia biomass were studied in batch systems. Aqueous solutions of Ni with starting concentrations between 1000 and 2000J.lmolll gave the most efficient Ni removal by Azalla biomass. For Cu the optimum starting concentration for adsorption was 50J.lmol/l. The adsorption capacity of both eu and Ni increased as the starting pH of the sorption media increased. The optimum pH for Ni adsorption was found at pH 7 and for Cu, at pH 5. - Awlla biomass had a higher. maximum binding capacity (qrnax) for Cu than for Ni at pH 5. The removal of both Cu allct Ni showed little or no variation with the presence another metal in solution. Kinetic studies show that both Cu and Ni adsorbed rapidly onto the Azalia biomass. The removal of Cu and Ni from aqueous solutions using non-viable Azalia biomass was investigated in a lab scale fixed-bed column and an upscaled 4L column system. The nonviable Azalla filiculaides biomass when dried and used in a column for adsorption of Cu and Ni showed good physical stability under many different conditions. Preparation of the biomass before it could be used in the columns was very simple and did not involve any significant pretreatment steps. Prolonged exposure to UV light decreases Azalia biomass capacity for Ni and Cu adsorption. Column adsorption of Cu and Ni from aqueous solutions was successfully upscaled approximately 100 times. Relative to the lab scale column, the 4L column performed better for the uptake of Cu and Ni per gram of biomass. The larger column was also able to operate at relatively higher flow rates. The biomass showed good reusability with little change in the amount of Ni adsorbed in 10 consecutive cycles. Electron micrographs showecf little or no change in the physical structure and integrity of the Azolla biomass after exposure to mineral acids, Ni solution and high flow rates over 10 consecutive adsorption and desorption cycles. As much as 80% Ni and 70 % Cu was recovered when desorption profiles were generated using O.lMHCI as a desorption agent. The 4L column system was also tested using a highly concen~rat:~ Ni plating bath solution.(Nicrolyte 1). Only 18 % of the Ni could be removed from the expended Nicrolyte 1 pla~Jng solution after treating only 25L, indicating that Azolla biomass is more suited for removal of metals from more dilute industrial effluents.
- Full Text:
- Date Issued: 2001
Rendering Primitives for a Virtual Holodeck
- Morkel, Chantelle, Bangay, Shaun D
- Authors: Morkel, Chantelle , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432795 , vital:72901 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/039virtualholodeck/paper02.pdf
- Description: The main objective of this research is to implement a “Star Trek”-like holodeck in a computer environment. An experiment to create graphical primitives and images solely out of spheres is being conducted. We investigate several approaches of creating primitives using spheres, and then using these primitives to create images. Initial results of this experiment are presented and we conclude that using spheres to create primitives and images is a viable approach to creating realistic-looking three-dimensional (3D) images.
- Full Text:
- Date Issued: 2001
- Authors: Morkel, Chantelle , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432795 , vital:72901 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/039virtualholodeck/paper02.pdf
- Description: The main objective of this research is to implement a “Star Trek”-like holodeck in a computer environment. An experiment to create graphical primitives and images solely out of spheres is being conducted. We investigate several approaches of creating primitives using spheres, and then using these primitives to create images. Initial results of this experiment are presented and we conclude that using spheres to create primitives and images is a viable approach to creating realistic-looking three-dimensional (3D) images.
- Full Text:
- Date Issued: 2001
Research for health and life: life giving light
- Authors: Burnett, Mary
- Date: 2001
- Subjects: Nyokong, Tebello
- Language: English
- Type: Article , text
- Identifier: vital:7179 , http://hdl.handle.net/10962/d1006185 , Nyokong, Tebello
- Description: The elimination of certain cancers with light, known as photodynamic therapy, is a relatively new technique that has mainly been used in Russia, the USA and some parts of Europe, but with remarkable effectiveness. Professor Tebello Nyokong of the Department of Chemistry , at Rhodes University, Grahamstown, is collaborating with Professor David Phillips of the Imperial College, London, as part of the AtlantIC Alliance which also involves Emory University, Atlanta and the Georgia Institute of Technology, both in Atlanta, SA.
- Full Text:
- Date Issued: 2001
- Authors: Burnett, Mary
- Date: 2001
- Subjects: Nyokong, Tebello
- Language: English
- Type: Article , text
- Identifier: vital:7179 , http://hdl.handle.net/10962/d1006185 , Nyokong, Tebello
- Description: The elimination of certain cancers with light, known as photodynamic therapy, is a relatively new technique that has mainly been used in Russia, the USA and some parts of Europe, but with remarkable effectiveness. Professor Tebello Nyokong of the Department of Chemistry , at Rhodes University, Grahamstown, is collaborating with Professor David Phillips of the Imperial College, London, as part of the AtlantIC Alliance which also involves Emory University, Atlanta and the Georgia Institute of Technology, both in Atlanta, SA.
- Full Text:
- Date Issued: 2001
Research portfolio
- Authors: Daphney, Robert
- Date: 2001
- Subjects: Teachers colleges -- South Africa -- Eastern Cape Competency-based education -- South Africa -- Eastern Cape Geography -- Curricula Geography -- Fieldwork -- Study and teaching Geography -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1828 , http://hdl.handle.net/10962/d1003714
- Description: This portfolio of work represents three research projects on issues related to teacher education. The research was undertaken at Dr. W.B. Rubusana College of Education over a period of three years. The first project is a situational analysis that attempts to determine whether the college is capable of meeting the challenges placed on it by the evolving South African Educational System. The key finding is that the college is not ready to embark on the changes required by the Ministry of Education chiefly because its educators and learners are seemingly not ready to embrace change. The second project is a case study that attempts to determine whether a group of 12 Senior Primary students at the college are able to interpret photographs of the local environment and as such provide evidence of their ability to be environmental educators through the medium of geography. The findings indicate that they are only able to read the photographs at a very superficial level. Their poor communication skills and their disadvantaged backgrounds seem to prevent them from achieving the level of thinking required for them to be effective environmental educators. The third project describes, analyses and evaluates a fieldwork study done with a class of Senior Primary students at the college. While the students did not achieve the necessary progression from 'look and see' to 'enquiry based' fieldwork the project was valuable in that it was an educative experience for both teacher and learner and provides evidence of the value of action research and reflective teaching.
- Full Text:
- Date Issued: 2001
- Authors: Daphney, Robert
- Date: 2001
- Subjects: Teachers colleges -- South Africa -- Eastern Cape Competency-based education -- South Africa -- Eastern Cape Geography -- Curricula Geography -- Fieldwork -- Study and teaching Geography -- Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1828 , http://hdl.handle.net/10962/d1003714
- Description: This portfolio of work represents three research projects on issues related to teacher education. The research was undertaken at Dr. W.B. Rubusana College of Education over a period of three years. The first project is a situational analysis that attempts to determine whether the college is capable of meeting the challenges placed on it by the evolving South African Educational System. The key finding is that the college is not ready to embark on the changes required by the Ministry of Education chiefly because its educators and learners are seemingly not ready to embrace change. The second project is a case study that attempts to determine whether a group of 12 Senior Primary students at the college are able to interpret photographs of the local environment and as such provide evidence of their ability to be environmental educators through the medium of geography. The findings indicate that they are only able to read the photographs at a very superficial level. Their poor communication skills and their disadvantaged backgrounds seem to prevent them from achieving the level of thinking required for them to be effective environmental educators. The third project describes, analyses and evaluates a fieldwork study done with a class of Senior Primary students at the college. While the students did not achieve the necessary progression from 'look and see' to 'enquiry based' fieldwork the project was valuable in that it was an educative experience for both teacher and learner and provides evidence of the value of action research and reflective teaching.
- Full Text:
- Date Issued: 2001
Research projects
- Authors: Adusei-Owusu, James
- Date: 2001
- Subjects: Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1740 , http://hdl.handle.net/10962/d1003624 , Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Description: RESEARCH PROJECTS: 1 RESEARCH PROJECT ONE: A literature review: Constructivism: An alternate approach to teaching and learning. Abstract The constructivist perspectives on learning have helped enhance science educators' understanding of how students make sense of their lived experiences. Constructivism purports to be a transformation of the traditional curriculum. As such this article starts with a brief overview of behaviorism: the scientific approach to education. The main tenets underlying constructivism, how constructivism guides educators to change their classroom practice, and the implications to science teaching have been reviewed. 2 RESEARCH PROJECT TWO (Empirical study): Being Constructive: College students' learning of work and heat as aspects of the energy concept based a constructivist approach. Abstract This study is an extension of a literature review on constructivism as an alternate teaching and learning approach discussed in research project one. It is an empirical study concerning the use of a learning module based on a constructivist approach to develop pre-service student teachers' understanding of work and heat as aspects of the energy concept. The data consisted mainly of transcripts of students' interviews, written responses to questionnaires designed in the form of a worksheet, and comments from non-participant observers and students. The results seem to suggest that a carefully designed learning module based on a constructivist teaching and learning approach may be a valuable tool in developing pre-service student teachers' understanding of work and heat. 3 RESEARCH PROJECT THREE (Empirical study): A College in transition: A case study of the readiness of a college in the Eastern Cape province to implement Outcomes-Based Education in an Education Development centre. Abstract Curriculum 2005 premised on Outcomes-Based Education is the new curriculum framework for South Africa. It signifies a paradigm shift in education from the traditional 'telling-listening' relationship between the teacher and the learner to one that emphasises leamer-centred approach to the teaching process. Teachers, though recognized as crucial to the educational transformation process in the country have also being identified as ill-equipped to meet the challenges posed by Outcomes-Based Education. This study starts with a brief overview of the South African curriculum and the main tenets underlying Outcomes-Based Education. The institutional conditions and whether the lecturers at a college in the Eastern Cape province perceive the need for a change in their classroom practice were also investigated. Bearing in mind the need for further research to validate the findings of this study, positive indicators that emerged from the study suggest the readiness of the college to implement Outcomes-Based Education at the proposed Education Development Centre.
- Full Text:
- Date Issued: 2001
- Authors: Adusei-Owusu, James
- Date: 2001
- Subjects: Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1740 , http://hdl.handle.net/10962/d1003624 , Constructivism (Education) , Review literature , College students -- Study and teaching , Teaching -- Methods , Competency based education -- Eastern Cape (South Africa)
- Description: RESEARCH PROJECTS: 1 RESEARCH PROJECT ONE: A literature review: Constructivism: An alternate approach to teaching and learning. Abstract The constructivist perspectives on learning have helped enhance science educators' understanding of how students make sense of their lived experiences. Constructivism purports to be a transformation of the traditional curriculum. As such this article starts with a brief overview of behaviorism: the scientific approach to education. The main tenets underlying constructivism, how constructivism guides educators to change their classroom practice, and the implications to science teaching have been reviewed. 2 RESEARCH PROJECT TWO (Empirical study): Being Constructive: College students' learning of work and heat as aspects of the energy concept based a constructivist approach. Abstract This study is an extension of a literature review on constructivism as an alternate teaching and learning approach discussed in research project one. It is an empirical study concerning the use of a learning module based on a constructivist approach to develop pre-service student teachers' understanding of work and heat as aspects of the energy concept. The data consisted mainly of transcripts of students' interviews, written responses to questionnaires designed in the form of a worksheet, and comments from non-participant observers and students. The results seem to suggest that a carefully designed learning module based on a constructivist teaching and learning approach may be a valuable tool in developing pre-service student teachers' understanding of work and heat. 3 RESEARCH PROJECT THREE (Empirical study): A College in transition: A case study of the readiness of a college in the Eastern Cape province to implement Outcomes-Based Education in an Education Development centre. Abstract Curriculum 2005 premised on Outcomes-Based Education is the new curriculum framework for South Africa. It signifies a paradigm shift in education from the traditional 'telling-listening' relationship between the teacher and the learner to one that emphasises leamer-centred approach to the teaching process. Teachers, though recognized as crucial to the educational transformation process in the country have also being identified as ill-equipped to meet the challenges posed by Outcomes-Based Education. This study starts with a brief overview of the South African curriculum and the main tenets underlying Outcomes-Based Education. The institutional conditions and whether the lecturers at a college in the Eastern Cape province perceive the need for a change in their classroom practice were also investigated. Bearing in mind the need for further research to validate the findings of this study, positive indicators that emerged from the study suggest the readiness of the college to implement Outcomes-Based Education at the proposed Education Development Centre.
- Full Text:
- Date Issued: 2001
Review of the deep-sea anglerfishes (Lophiiformes: Ceratioidei) of southern Africa
- Anderson, M Eric, Leslie, Robin W
- Authors: Anderson, M Eric , Leslie, Robin W
- Date: 2001
- Language: English
- Type: Text
- Identifier: vital:15029 , http://hdl.handle.net/10962/d1019903 , ISSN 0073-4381 , Ichthyological Bulletin of the J.L.B. Smith Institute of Ichthyology; No. 70
- Description: Deep-sea anglerfishes (Lophiiformes, Ceratioidei) of the familes Caulophrynidae, Melanocetidae, Himantolophidae, Diceratiidae, Oneirodidae, Thaumatichthyidae, Centrophrynidae, Ceratiidae, Gigantactinidae and Linophrynidae from southern Africa are reviewed since the publication of the book Smiths’ Sea Fishes (1986, 1991). Twenty-three new records of ceratioid anglerfishes are reported for the region, bringing the total to 32. No new taxa are described. The faunal area for southern African deep-sea fishes is expanded from that of Smiths’ Sea Fishes in order to include several literature records and recognize the broad distributions of these fishes through the deep-pelagic Atlantic/Indo-Pacific transit zone. Keys to all families, genera and species, as well as descriptions of all southern African specimens, are provided. The bulk of this material was collected during research cruises of South Africa’s RS AFRICANA and MEIRING NAUDE. , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 2001
- Authors: Anderson, M Eric , Leslie, Robin W
- Date: 2001
- Language: English
- Type: Text
- Identifier: vital:15029 , http://hdl.handle.net/10962/d1019903 , ISSN 0073-4381 , Ichthyological Bulletin of the J.L.B. Smith Institute of Ichthyology; No. 70
- Description: Deep-sea anglerfishes (Lophiiformes, Ceratioidei) of the familes Caulophrynidae, Melanocetidae, Himantolophidae, Diceratiidae, Oneirodidae, Thaumatichthyidae, Centrophrynidae, Ceratiidae, Gigantactinidae and Linophrynidae from southern Africa are reviewed since the publication of the book Smiths’ Sea Fishes (1986, 1991). Twenty-three new records of ceratioid anglerfishes are reported for the region, bringing the total to 32. No new taxa are described. The faunal area for southern African deep-sea fishes is expanded from that of Smiths’ Sea Fishes in order to include several literature records and recognize the broad distributions of these fishes through the deep-pelagic Atlantic/Indo-Pacific transit zone. Keys to all families, genera and species, as well as descriptions of all southern African specimens, are provided. The bulk of this material was collected during research cruises of South Africa’s RS AFRICANA and MEIRING NAUDE. , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 2001
Revisiting nomenclature: 'Early Iron Age', 'First-Millennium Agriculturist', or what?
- Authors: Steele, John
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/934 , vital:30067
- Description: As an art historian who has recently become fascinated by First-Millennium Agriculturist ceramics, I have come across several attempts at dealing with an issue of appropriate nomenclature for desigrrating this era. Conceptual frameworks are articulated using words, yet an apparent discomfort with the term Early Iron Age has seemingly not led to a consistently used altemative. I have been wondering about this and, with respect, offer my thoughts on the matter in a hope that debate will be furthered. Hereunder I utilise aspects of the KwaZulu-Natal and Eastem Cape first millennium ceramic sequence to address some significances associated with such artefacts in interpretations of the past, and then discuss some ways in which ideas of particular social contexts are embedded in language. Thereafter introduction of the term Iron Age into South African archaeology is referred to with reference to past and current usage, and advantages/disadvantages of alternatives are suggested.
- Full Text:
- Date Issued: 2001
- Authors: Steele, John
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/934 , vital:30067
- Description: As an art historian who has recently become fascinated by First-Millennium Agriculturist ceramics, I have come across several attempts at dealing with an issue of appropriate nomenclature for desigrrating this era. Conceptual frameworks are articulated using words, yet an apparent discomfort with the term Early Iron Age has seemingly not led to a consistently used altemative. I have been wondering about this and, with respect, offer my thoughts on the matter in a hope that debate will be furthered. Hereunder I utilise aspects of the KwaZulu-Natal and Eastem Cape first millennium ceramic sequence to address some significances associated with such artefacts in interpretations of the past, and then discuss some ways in which ideas of particular social contexts are embedded in language. Thereafter introduction of the term Iron Age into South African archaeology is referred to with reference to past and current usage, and advantages/disadvantages of alternatives are suggested.
- Full Text:
- Date Issued: 2001
Rhodes University Graduation Ceremony 2001
- Authors: Rhodes University
- Date: 2001
- Language: English
- Type: text
- Identifier: vital:8146 , http://hdl.handle.net/10962/d1007296
- Description: Rhodes University Graduation Ceremonies 1820 Settlers National Monument Friday, 6 April 2001 at 10:30; 18:00 [and] Saturday, 7 April 2001 at 10:30 , Graduation Ceremony Christian Centre, Wyse Street, East London Friday, 1 May 2001 at 18:00
- Full Text:
- Date Issued: 2001
- Authors: Rhodes University
- Date: 2001
- Language: English
- Type: text
- Identifier: vital:8146 , http://hdl.handle.net/10962/d1007296
- Description: Rhodes University Graduation Ceremonies 1820 Settlers National Monument Friday, 6 April 2001 at 10:30; 18:00 [and] Saturday, 7 April 2001 at 10:30 , Graduation Ceremony Christian Centre, Wyse Street, East London Friday, 1 May 2001 at 18:00
- Full Text:
- Date Issued: 2001
Rhodes University Research Report 2001
- Authors: Rhodes University
- Date: 2001
- Language: English
- Type: Text
- Identifier: vital:556 , http://hdl.handle.net/10962/d1011936
- Description: [From Introduction] This is the first formal research report published by Rhodes University. The reason research reports have not been published previously is that the annual Council and Senate report was largely a research report and it was unnecessary to duplicate this report. However, the required format of the University’s Annual Report has changed considerably from 2001 and no longer includes detailed information on the research outputs. I would like to add my congratulations to that of the Vice-Chancellor to all the staff and postgraduate students for their research efforts in 2001. Rhodes continues to be the leading Institution in South Africa in terms of research outputs relative to its size (determined by Government subsidy income). This is very significant and it is critical that this prominence be maintained, particularly in view of the recent restructuring of Higher Education in South Africa and the greater emphasis likely to be placed on research productivity by the revised funding formula. Research at Rhodes is actively supported by the University’s Management and a variety of internal support services including, amongst others, the Library, Information Technology, laboratory and equipment support services and the entire academic, administrative and financial infrastructure. Without this support it would be impossible to conduct research. Special thanks must go to the staff in the Research Office for all their efforts in promoting research and in particular to Moira Pogrund who complied the majority of this report.
- Full Text:
- Date Issued: 2001
- Authors: Rhodes University
- Date: 2001
- Language: English
- Type: Text
- Identifier: vital:556 , http://hdl.handle.net/10962/d1011936
- Description: [From Introduction] This is the first formal research report published by Rhodes University. The reason research reports have not been published previously is that the annual Council and Senate report was largely a research report and it was unnecessary to duplicate this report. However, the required format of the University’s Annual Report has changed considerably from 2001 and no longer includes detailed information on the research outputs. I would like to add my congratulations to that of the Vice-Chancellor to all the staff and postgraduate students for their research efforts in 2001. Rhodes continues to be the leading Institution in South Africa in terms of research outputs relative to its size (determined by Government subsidy income). This is very significant and it is critical that this prominence be maintained, particularly in view of the recent restructuring of Higher Education in South Africa and the greater emphasis likely to be placed on research productivity by the revised funding formula. Research at Rhodes is actively supported by the University’s Management and a variety of internal support services including, amongst others, the Library, Information Technology, laboratory and equipment support services and the entire academic, administrative and financial infrastructure. Without this support it would be impossible to conduct research. Special thanks must go to the staff in the Research Office for all their efforts in promoting research and in particular to Moira Pogrund who complied the majority of this report.
- Full Text:
- Date Issued: 2001
Rural resettlement scheme evaluation: a case study of the Mfengu in Tsitsikamma
- Authors: Fakudze, Churchill M
- Date: 2001
- Subjects: Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3309 , http://hdl.handle.net/10962/d1003097 , Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Description: In 1997 South Africa came out with a policy aimed at addressing the legacy of apartheid in respect of an unequal division of land in the country. About 3.5 million people were moved from rural and urban areas between 1960 and 1980 and deposited in the reserves or areas designed for the exclusive occupation of black people. The new land policy attempts to deal with the resultant problems. The policy advocates a three-pronged approach to land reform encompassing (i) land restitution, (ii) land redistribution and (iii) land tenure reform. A number of projects have been carried out under these three aspects. This study aims to investigate and evaluate the results of a completed land restitution case. The Mfengu of Tsitsikamma was chosen as a case study because the people have moved back and are now living on their land. The Mfengu were dispossessed of their land in 1977 by the apartheid government and their land was returned in 1994. Although this case was processed outside of the land restitution legislation (Restitution of Land Rights Act, 22 of 1994), all restitution cases where people return to their original land have to deal with the problems of resettlement. From its involvement in various involuntary resettlement projects, the World Bank concluded that the new communities of resettlers should be designed as a viable settlement system equipped with infrastructure and services and integrated in the regional socio-economic context. The host communities receiving the resettlers should be assisted to overcome possible adverse social and environmental effects from the increased population density. These concerns are valid for the South African situation, and the question is, whether this resettlement encapsulates the above. The goals of the research are twofold. To evaluate the efficiency and effectiveness of the resettlement project and its sustainability. In particular focussing on the constraints to the implementation of the land policy. Research questions include the following: How was the project carried out? Is the resettlement integrated into the socio-economic and development planning of the area? How viable and sustainable is the new settlement? What are the major problems and challenges facing this area and how can they be overcome?
- Full Text:
- Date Issued: 2001
- Authors: Fakudze, Churchill M
- Date: 2001
- Subjects: Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3309 , http://hdl.handle.net/10962/d1003097 , Land settlement , Land settlement -- South Africa -- Tsitsikamma , Land settlement -- Developing countries , Land settlement -- South Africa
- Description: In 1997 South Africa came out with a policy aimed at addressing the legacy of apartheid in respect of an unequal division of land in the country. About 3.5 million people were moved from rural and urban areas between 1960 and 1980 and deposited in the reserves or areas designed for the exclusive occupation of black people. The new land policy attempts to deal with the resultant problems. The policy advocates a three-pronged approach to land reform encompassing (i) land restitution, (ii) land redistribution and (iii) land tenure reform. A number of projects have been carried out under these three aspects. This study aims to investigate and evaluate the results of a completed land restitution case. The Mfengu of Tsitsikamma was chosen as a case study because the people have moved back and are now living on their land. The Mfengu were dispossessed of their land in 1977 by the apartheid government and their land was returned in 1994. Although this case was processed outside of the land restitution legislation (Restitution of Land Rights Act, 22 of 1994), all restitution cases where people return to their original land have to deal with the problems of resettlement. From its involvement in various involuntary resettlement projects, the World Bank concluded that the new communities of resettlers should be designed as a viable settlement system equipped with infrastructure and services and integrated in the regional socio-economic context. The host communities receiving the resettlers should be assisted to overcome possible adverse social and environmental effects from the increased population density. These concerns are valid for the South African situation, and the question is, whether this resettlement encapsulates the above. The goals of the research are twofold. To evaluate the efficiency and effectiveness of the resettlement project and its sustainability. In particular focussing on the constraints to the implementation of the land policy. Research questions include the following: How was the project carried out? Is the resettlement integrated into the socio-economic and development planning of the area? How viable and sustainable is the new settlement? What are the major problems and challenges facing this area and how can they be overcome?
- Full Text:
- Date Issued: 2001
SADTU draft input on WHITE PAPER No. 5 on early childhood development
- SADTU
- Authors: SADTU
- Date: 2001
- Subjects: SADTU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/176156 , vital:42665
- Description: SADTU welcomes the release of White Paper No. 5 on Early Childhood Development. We thank the Ministry and Department of Education for affording us this opportunity to make an input. We are however concerned that the process during its development excluded stakeholder participation.
- Full Text:
- Date Issued: 2001
- Authors: SADTU
- Date: 2001
- Subjects: SADTU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/176156 , vital:42665
- Description: SADTU welcomes the release of White Paper No. 5 on Early Childhood Development. We thank the Ministry and Department of Education for affording us this opportunity to make an input. We are however concerned that the process during its development excluded stakeholder participation.
- Full Text:
- Date Issued: 2001
Sapphic experience: lesbian gender identity development and diversity
- Authors: Crowley, Michelle Laureen
- Date: 2001
- Subjects: Lesbian couples Gender identity Sexual orientation Heterosexual women Lesbian feminists
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2956 , http://hdl.handle.net/10962/d1002465
- Description: This dissertation explores lesbian experience, or the psychological meaning of being lesbian from the point of view of women who call themselves lesbian. The researcher suspended the binary paradigm of sex and gender, and argued that lesbians' identity development must be understood against the background of how patriarchy understands the category 'woman' through history. Towards this purpose the pOSition of women in the West, as well as contemporary images and literature about lesbians, was reviewed. On the basis of this review questions about lesbian gender construction, lesbian identity development and lesbian individuation were identified. In order to access the psychological meaning of being lesbian, or lesbian experience from the inside out, the dream-series of three lesbians constituted an empirical basis for further exploration. These dream-series were amplified with intensive face-to-face interviews, transcribed, and subjected to a hermeneutic-phenomenological inductive method. Common inter-case concerns were identified and synthesized. In dialogue with the literature reviewed, twenty-two statements of meaning about being lesbian were distilled. These revealed two possible constructions of gender for primary lesbians. In addition, primary lesbians involved in the research demonstrated remarkable flexibility with respect to their gender orientations and gender identifications, were in the process of integrating with and differentiating from different aspects of their masculine and feminine potentials, and developed and negotiated their gender identities in relationship to both their lovers and friends. The explication also revealed that participants identified with archetypal aspects of the father that their fathers' did not express, and desired archetypal aspects of the mother that their mother's did not express. Finally, in so much as the method distinguished ~ sex, sexual identity and sexual orientation from gender, gender identity, gender identification and gender orientation, it may prove useful for exploring gender in heterosexual relating.
- Full Text:
- Date Issued: 2001
- Authors: Crowley, Michelle Laureen
- Date: 2001
- Subjects: Lesbian couples Gender identity Sexual orientation Heterosexual women Lesbian feminists
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2956 , http://hdl.handle.net/10962/d1002465
- Description: This dissertation explores lesbian experience, or the psychological meaning of being lesbian from the point of view of women who call themselves lesbian. The researcher suspended the binary paradigm of sex and gender, and argued that lesbians' identity development must be understood against the background of how patriarchy understands the category 'woman' through history. Towards this purpose the pOSition of women in the West, as well as contemporary images and literature about lesbians, was reviewed. On the basis of this review questions about lesbian gender construction, lesbian identity development and lesbian individuation were identified. In order to access the psychological meaning of being lesbian, or lesbian experience from the inside out, the dream-series of three lesbians constituted an empirical basis for further exploration. These dream-series were amplified with intensive face-to-face interviews, transcribed, and subjected to a hermeneutic-phenomenological inductive method. Common inter-case concerns were identified and synthesized. In dialogue with the literature reviewed, twenty-two statements of meaning about being lesbian were distilled. These revealed two possible constructions of gender for primary lesbians. In addition, primary lesbians involved in the research demonstrated remarkable flexibility with respect to their gender orientations and gender identifications, were in the process of integrating with and differentiating from different aspects of their masculine and feminine potentials, and developed and negotiated their gender identities in relationship to both their lovers and friends. The explication also revealed that participants identified with archetypal aspects of the father that their fathers' did not express, and desired archetypal aspects of the mother that their mother's did not express. Finally, in so much as the method distinguished ~ sex, sexual identity and sexual orientation from gender, gender identity, gender identification and gender orientation, it may prove useful for exploring gender in heterosexual relating.
- Full Text:
- Date Issued: 2001
Scales of mussel bed complexity: structure, associated biota and recruitment
- Lawrie, S M, McQuaid, Christopher D
- Authors: Lawrie, S M , McQuaid, Christopher D
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6956 , http://hdl.handle.net/10962/d1011996
- Description: Hierarchically scaled surveys were carried out on beds of the brown mussel Perna perna (Linnaeus) on the South coast of South Africa. The object was to assess spatial and temporal variations in the complexity of mussel beds and to investigate relationships between mussel bed complexity and mussel recruitment. Complexity was divided into three components: physical complexity; demographic complexity; associated biota. A series of variables within each component were recorded at two different scales (10 and 50 cm) within nested quadrats on three separate occasions. The nested ANOVA design explicitly incorporated spatial scale as levels of the ANOVA. These scales were: shores (areas 1 km in length separated by 25 km); transects (areas 20 m in length separated by 100s of meters); 50×50-cm quadrats separated by meters and 10×10-cm quadrats separated by cm) This approach was intended to generate hypotheses concerning direct associations between recruitment and complexity versus co-variation due external processes. Three main questions were addressed: (1) At what scale does each variable of complexity exhibit greatest significant variation? (2) At these scales is there similar ranking of variables of complexity and recruitment? (3) Within this/these scales, is there any significant relationship between the variables measured and mussel recruitment? On two occasions (Nov. 97 and Mar. 98) the majority of variables showed greatest significant variation at the transect-scale. On a third occasion (Oct. 97) most variables showed greatest significant variation at the quadrat-scale and the site-scale. On all occasions a markedly high percentage of the variation encountered also occurred at the smallest scale of the study, i.e., the residual scale of the ANOVA analyses. Some similarity in the ranking of variables occurred at the transect scale. Within the transect-scale, there was little indication of any relationship between variables of complexity and recruitment. Relationships were inconsistent either among transects or among sampling occasions. Overall, the results suggest that a high degree of variation in mussel bed complexity consistently occurs at very small scales. High components of variance generally also occur at one or more larger scales; however, these scales vary with season. Mussel recruitment does not appear to be directly affected by complexity of mussel beds. Instead it appears external factors may influence both complexity and recruitment independently. In addition recruitment may influence complexity rather than vice versa.
- Full Text:
- Date Issued: 2001
- Authors: Lawrie, S M , McQuaid, Christopher D
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6956 , http://hdl.handle.net/10962/d1011996
- Description: Hierarchically scaled surveys were carried out on beds of the brown mussel Perna perna (Linnaeus) on the South coast of South Africa. The object was to assess spatial and temporal variations in the complexity of mussel beds and to investigate relationships between mussel bed complexity and mussel recruitment. Complexity was divided into three components: physical complexity; demographic complexity; associated biota. A series of variables within each component were recorded at two different scales (10 and 50 cm) within nested quadrats on three separate occasions. The nested ANOVA design explicitly incorporated spatial scale as levels of the ANOVA. These scales were: shores (areas 1 km in length separated by 25 km); transects (areas 20 m in length separated by 100s of meters); 50×50-cm quadrats separated by meters and 10×10-cm quadrats separated by cm) This approach was intended to generate hypotheses concerning direct associations between recruitment and complexity versus co-variation due external processes. Three main questions were addressed: (1) At what scale does each variable of complexity exhibit greatest significant variation? (2) At these scales is there similar ranking of variables of complexity and recruitment? (3) Within this/these scales, is there any significant relationship between the variables measured and mussel recruitment? On two occasions (Nov. 97 and Mar. 98) the majority of variables showed greatest significant variation at the transect-scale. On a third occasion (Oct. 97) most variables showed greatest significant variation at the quadrat-scale and the site-scale. On all occasions a markedly high percentage of the variation encountered also occurred at the smallest scale of the study, i.e., the residual scale of the ANOVA analyses. Some similarity in the ranking of variables occurred at the transect scale. Within the transect-scale, there was little indication of any relationship between variables of complexity and recruitment. Relationships were inconsistent either among transects or among sampling occasions. Overall, the results suggest that a high degree of variation in mussel bed complexity consistently occurs at very small scales. High components of variance generally also occur at one or more larger scales; however, these scales vary with season. Mussel recruitment does not appear to be directly affected by complexity of mussel beds. Instead it appears external factors may influence both complexity and recruitment independently. In addition recruitment may influence complexity rather than vice versa.
- Full Text:
- Date Issued: 2001
Sedimentology of the Karoo Supergroup in the Tuli Basin (Limpompo River area, South Africa)
- Authors: Bordy, Emese M
- Date: 2001
- Subjects: River sediments -- South Africa Sedimentology Limpopo river Sedimentology -- Limpopo river Limpopo river (South africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4999 , http://hdl.handle.net/10962/d1005612
- Description: The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) consist of various terrigenous clastic and chemical deposits (parabreccias, conglo-breccias, conglomerates, sandstones, fine-grained sediments, calcretes and silc~etes). Four stratigraphic units were identified: the Basal, Middle and· Upper Units, and the CI~rens Formation. The palaeo-environmental reconstructions of the four stratigraphic units are based on evidence provided by primary sedimentary structures, palaeo-flow measurements, clast size/shape analysis, petrographic studies, palaeontological findings, borehole data and stratigraphic relations. The facies associations of the Basal Unit are interpreted as colluvial fan and low sinuosity, braid~d river channel with coal-bearing overbank and thaw-lake deposits. The interpreted depositional environment implies a cold climate, non-glacial subarctic fluvio-Iacustrine system. The current indicators of the palaeo-river system suggest flow direction from ENE to WSW. The lithologies of the Basal Unit are very similar to the deposits of the fluvial interval in the Vryheid Formation (Ecca Group) of the main Karoo Basin. There is no indubitable evidence for glacial activity (e.g. striated pavements or clasts, varvites, etc.), therefore the presence of unequivocal Dwyka Group correlatives in the Tuli Basin remains uncertain. The sedimentary structures and palaeo-current analysis indicate that the beds of the Middle Unit were deposited by an ancient river system flowing in a north-northwesterly direction. A lack of good quality exposures did not allow the reconstruction of the fluvial style, but the available data indicate a high-energy, perhaps braided fluvial system. The lack of bio- and chronostr~~igraphic control hampers precise correlation and enables only the lithocorrelation of the Middle Unit with other braided river systems either in the Beaufort Group or in the Molteno Formation of the main Karoo Basin. The depositional environment of the Upper Unit is interpreted as a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the unit, the climate was semi-arid with sparse precipitation resulting -iFlhighmagnitude, low-frequency devastating flash floods. The sediments were built out from a distant northwesterly source to the southeast. The unambiguous correspondence between the Upper Unit and the Elliot Formation (main Karoo Basin) is provided by lithological similarities and prosauropod dinosaurs remains. The palaeo-geographic picture of the Clarens Fonnation indicates a westerly windsdominated erg environment with migrating transverse dune types. The ephemeral stream deposits, fossil wood and trace fossils are only present in the lower part of the Formation, indicating that the wet-desert conditions were progressively replaced by dry-desert conditions. Based on lithological and palaeontological evidence, the Formation correlates with the Clarens Formation in the main Karoo Basin. At this stage, it remains difficult to establish the exact cause of the regional palaeo-slope changes during the deposition of the Karoo Supergroup in the Tuli Basin. It is probable that foreland system tectonics, which affected the lower part of the Supergroup (Basal Unit and Middle Unit?), were replaced by incipient continental extension and rift related tectonic movements in the Middle and Upper Units, and Clarens Formation.
- Full Text:
- Date Issued: 2001
- Authors: Bordy, Emese M
- Date: 2001
- Subjects: River sediments -- South Africa Sedimentology Limpopo river Sedimentology -- Limpopo river Limpopo river (South africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4999 , http://hdl.handle.net/10962/d1005612
- Description: The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) consist of various terrigenous clastic and chemical deposits (parabreccias, conglo-breccias, conglomerates, sandstones, fine-grained sediments, calcretes and silc~etes). Four stratigraphic units were identified: the Basal, Middle and· Upper Units, and the CI~rens Formation. The palaeo-environmental reconstructions of the four stratigraphic units are based on evidence provided by primary sedimentary structures, palaeo-flow measurements, clast size/shape analysis, petrographic studies, palaeontological findings, borehole data and stratigraphic relations. The facies associations of the Basal Unit are interpreted as colluvial fan and low sinuosity, braid~d river channel with coal-bearing overbank and thaw-lake deposits. The interpreted depositional environment implies a cold climate, non-glacial subarctic fluvio-Iacustrine system. The current indicators of the palaeo-river system suggest flow direction from ENE to WSW. The lithologies of the Basal Unit are very similar to the deposits of the fluvial interval in the Vryheid Formation (Ecca Group) of the main Karoo Basin. There is no indubitable evidence for glacial activity (e.g. striated pavements or clasts, varvites, etc.), therefore the presence of unequivocal Dwyka Group correlatives in the Tuli Basin remains uncertain. The sedimentary structures and palaeo-current analysis indicate that the beds of the Middle Unit were deposited by an ancient river system flowing in a north-northwesterly direction. A lack of good quality exposures did not allow the reconstruction of the fluvial style, but the available data indicate a high-energy, perhaps braided fluvial system. The lack of bio- and chronostr~~igraphic control hampers precise correlation and enables only the lithocorrelation of the Middle Unit with other braided river systems either in the Beaufort Group or in the Molteno Formation of the main Karoo Basin. The depositional environment of the Upper Unit is interpreted as a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the unit, the climate was semi-arid with sparse precipitation resulting -iFlhighmagnitude, low-frequency devastating flash floods. The sediments were built out from a distant northwesterly source to the southeast. The unambiguous correspondence between the Upper Unit and the Elliot Formation (main Karoo Basin) is provided by lithological similarities and prosauropod dinosaurs remains. The palaeo-geographic picture of the Clarens Fonnation indicates a westerly windsdominated erg environment with migrating transverse dune types. The ephemeral stream deposits, fossil wood and trace fossils are only present in the lower part of the Formation, indicating that the wet-desert conditions were progressively replaced by dry-desert conditions. Based on lithological and palaeontological evidence, the Formation correlates with the Clarens Formation in the main Karoo Basin. At this stage, it remains difficult to establish the exact cause of the regional palaeo-slope changes during the deposition of the Karoo Supergroup in the Tuli Basin. It is probable that foreland system tectonics, which affected the lower part of the Supergroup (Basal Unit and Middle Unit?), were replaced by incipient continental extension and rift related tectonic movements in the Middle and Upper Units, and Clarens Formation.
- Full Text:
- Date Issued: 2001
Sedimentology of the upper Karoo fluvial strata in the Tuli Basin, South Africa
- Bordy, Emese M, Catuneanu, O
- Authors: Bordy, Emese M , Catuneanu, O
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6731 , http://hdl.handle.net/10962/d1007540
- Description: The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) may be grouped in four stratigraphic units: the basal, middle and upper units, and the Clarens Formation. This paper presents the findings of the sedimentological investigation of the fluvial terrigenous clastic and chemical deposits of the upper unit. Evidence provided by primary sedimentary structures, palaeontological record, borehole data, palaeo-flow measurements and stratigraphic relations resulted in the palaeo-environmental reconstruction of the upper unit. The dominant facies assemblages are represented by sandstones and finer-grained sediments, which both can be interbedded with subordinate intraformational coarser facies. The facies assemblages of the upper unit are interpreted as deposits of a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the upper unit, the climate was semi-arid with sparse precipitation resulting in high-magnitude, low-frequency devastating flash floods. The current indicators of the palaeo-drainage system suggest flow direction from northwest to southeast, in a dominantly extensional tectonic setting. Based on sedimentologic and biostratigraphic evidence, the upper unit of the Tuli Basin correlates to the Elliot Formation in the main Karoo Basin to the south.
- Full Text:
- Date Issued: 2001
- Authors: Bordy, Emese M , Catuneanu, O
- Date: 2001
- Language: English
- Type: Article
- Identifier: vital:6731 , http://hdl.handle.net/10962/d1007540
- Description: The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) may be grouped in four stratigraphic units: the basal, middle and upper units, and the Clarens Formation. This paper presents the findings of the sedimentological investigation of the fluvial terrigenous clastic and chemical deposits of the upper unit. Evidence provided by primary sedimentary structures, palaeontological record, borehole data, palaeo-flow measurements and stratigraphic relations resulted in the palaeo-environmental reconstruction of the upper unit. The dominant facies assemblages are represented by sandstones and finer-grained sediments, which both can be interbedded with subordinate intraformational coarser facies. The facies assemblages of the upper unit are interpreted as deposits of a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the upper unit, the climate was semi-arid with sparse precipitation resulting in high-magnitude, low-frequency devastating flash floods. The current indicators of the palaeo-drainage system suggest flow direction from northwest to southeast, in a dominantly extensional tectonic setting. Based on sedimentologic and biostratigraphic evidence, the upper unit of the Tuli Basin correlates to the Elliot Formation in the main Karoo Basin to the south.
- Full Text:
- Date Issued: 2001
Silicon octaphenoxyphthalocyanines
- Maree, M David, Kuznetsova, Nina, Nyokong, Tebello
- Authors: Maree, M David , Kuznetsova, Nina , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/291591 , vital:56890 , xlink:href="https://doi.org/10.1016/S1010-6030(01)00409-9"
- Description: Photochemical properties of series of axially substituted silicon octaphenoxyphthalocyanines with aryloxy, siloxy, aminoalkoxy, esters of carboxylic acids and sulphonic acid esters residues as axial ligands were studied in dimethylsulfoxide (DMSO) solution. It was found, that under Q-band excitation axial ligands in compounds studied have the propensity to be changed by hydroxyl groups with quantum yields in the range 10−5 to 10−2 depending on the nature of the axial ligand. Axial substituent phototransformation was followed by slow photobleaching of dihydroxysilicon octaphenoxyphthalocyanine (photoproduct) in self-sensitized singlet oxygen mediated oxidation of the macrocycle. Singlet oxygen quantum yields were found to be in the range 0.15–0.20 for majority of the phthalocyanines (Pc) studied.
- Full Text:
- Date Issued: 2001
- Authors: Maree, M David , Kuznetsova, Nina , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/291591 , vital:56890 , xlink:href="https://doi.org/10.1016/S1010-6030(01)00409-9"
- Description: Photochemical properties of series of axially substituted silicon octaphenoxyphthalocyanines with aryloxy, siloxy, aminoalkoxy, esters of carboxylic acids and sulphonic acid esters residues as axial ligands were studied in dimethylsulfoxide (DMSO) solution. It was found, that under Q-band excitation axial ligands in compounds studied have the propensity to be changed by hydroxyl groups with quantum yields in the range 10−5 to 10−2 depending on the nature of the axial ligand. Axial substituent phototransformation was followed by slow photobleaching of dihydroxysilicon octaphenoxyphthalocyanine (photoproduct) in self-sensitized singlet oxygen mediated oxidation of the macrocycle. Singlet oxygen quantum yields were found to be in the range 0.15–0.20 for majority of the phthalocyanines (Pc) studied.
- Full Text:
- Date Issued: 2001
Simultaneous voltammetric determination of dopamine and serotonin on carbon paste electrodes modified with iron (II) phthalocyanine complexes
- Oni, Joshua, Nyokong, Tebello
- Authors: Oni, Joshua , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/291603 , vital:56891 , xlink:href="https://doi.org/10.1016/S0003-2670(01)00822-4"
- Description: Carbon paste electrodes (CPE) containing iron(II) phthalocyanine (FePc) and iron(II) tetrasulfophthalocyanine ([FeTSPc]4−) were used for the detection of dopamine (DA) and serotonin (5-HT). Both complexes showed catalytic activity towards the detection of DA and 5-HT. The catalytic activities of [FeTSPc]4− and FePc are compared with those of [CoTSPc]4−, [NiTSPc] 4−, CoPc and NiPc complexes and with those of metal(II) tetraaminophthalocyanines (MTAPc, where M=Ni, Co or Fe) complexes. A significant improvement in the reversibility of the DA oxidation couple was observed on [FeTSPc]4− and FePc modified CPE. [FeTSPc]4− and other [MTSPc]4− modified electrodes inhibited the detection of ascorbic acid (AA), a major interferent in the detection of DA. Simultaneous detection of DA and 5-HT on [FeTSPc]4− modified CPE, in the presence of AA, showed that AA does not interfere with the determination of both species. Also no interference between DA and 5-HT was observed.
- Full Text:
- Date Issued: 2001
- Authors: Oni, Joshua , Nyokong, Tebello
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/291603 , vital:56891 , xlink:href="https://doi.org/10.1016/S0003-2670(01)00822-4"
- Description: Carbon paste electrodes (CPE) containing iron(II) phthalocyanine (FePc) and iron(II) tetrasulfophthalocyanine ([FeTSPc]4−) were used for the detection of dopamine (DA) and serotonin (5-HT). Both complexes showed catalytic activity towards the detection of DA and 5-HT. The catalytic activities of [FeTSPc]4− and FePc are compared with those of [CoTSPc]4−, [NiTSPc] 4−, CoPc and NiPc complexes and with those of metal(II) tetraaminophthalocyanines (MTAPc, where M=Ni, Co or Fe) complexes. A significant improvement in the reversibility of the DA oxidation couple was observed on [FeTSPc]4− and FePc modified CPE. [FeTSPc]4− and other [MTSPc]4− modified electrodes inhibited the detection of ascorbic acid (AA), a major interferent in the detection of DA. Simultaneous detection of DA and 5-HT on [FeTSPc]4− modified CPE, in the presence of AA, showed that AA does not interfere with the determination of both species. Also no interference between DA and 5-HT was observed.
- Full Text:
- Date Issued: 2001
Singing in the streets
- Authors: Thomas, Cornelius
- Date: 2001
- Subjects: Musical groups Rock groups
- Type: article
- Identifier: http://hdl.handle.net/10962/32704 , vital:24072 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 017
- Description: Photocopied article from the newspaper The Daily Dispatch about the Belltones musical group
- Full Text:
- Date Issued: 2001
- Authors: Thomas, Cornelius
- Date: 2001
- Subjects: Musical groups Rock groups
- Type: article
- Identifier: http://hdl.handle.net/10962/32704 , vital:24072 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , MS 20 017
- Description: Photocopied article from the newspaper The Daily Dispatch about the Belltones musical group
- Full Text:
- Date Issued: 2001
Social parasitism by honeybee workers (Apis mellifera capensis Escholtz): host finding and resistance of hybrid host colonies
- Neumann, Peter, Radloff, Sarah E, Moritz, Robin F A, Hepburn, H Randall, Reece, Sacha L
- Authors: Neumann, Peter , Radloff, Sarah E , Moritz, Robin F A , Hepburn, H Randall , Reece, Sacha L
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6907 , http://hdl.handle.net/10962/d1011860
- Description: We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honeybee (Apis mellifera capensis) workers. Workers often join neighboring colonies by drifting, but long-range drifting (dispersal) to colonies far away from the maternal nests also rarely occurs. We tested the impact of queenstate and taxon of mother and host colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata, and their natural hybrids. Workers were paint-marked according to colony and reintroduced into their queenright or queenless mother colonies. After 10 days, 579 out of 12,034 labeled workers were recaptured in foreign colonies. We found that drifting and dispersing represent different behaviors, which were differently affected by taxon and queenstate of both mother and host colonies. Hybrid workers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than the hybrids. Dispersers from queenright A. m. capensis colonies were more often found in queenless host colonies and vice versa, indicating active host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different hosting mechanisms of foreign workers by hybrid colonies may also be responsible for the stability of the natural hybrid zone between A. m. capensis and A. m. scutellata.
- Full Text:
- Date Issued: 2001
- Authors: Neumann, Peter , Radloff, Sarah E , Moritz, Robin F A , Hepburn, H Randall , Reece, Sacha L
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6907 , http://hdl.handle.net/10962/d1011860
- Description: We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honeybee (Apis mellifera capensis) workers. Workers often join neighboring colonies by drifting, but long-range drifting (dispersal) to colonies far away from the maternal nests also rarely occurs. We tested the impact of queenstate and taxon of mother and host colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata, and their natural hybrids. Workers were paint-marked according to colony and reintroduced into their queenright or queenless mother colonies. After 10 days, 579 out of 12,034 labeled workers were recaptured in foreign colonies. We found that drifting and dispersing represent different behaviors, which were differently affected by taxon and queenstate of both mother and host colonies. Hybrid workers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than the hybrids. Dispersers from queenright A. m. capensis colonies were more often found in queenless host colonies and vice versa, indicating active host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different hosting mechanisms of foreign workers by hybrid colonies may also be responsible for the stability of the natural hybrid zone between A. m. capensis and A. m. scutellata.
- Full Text:
- Date Issued: 2001
SoDA : a model for the administration of separation of duty requirements in workflow systems
- Authors: Perelson, Stephen
- Date: 2001
- Subjects: Electronic data processing departments -- Security measures , Computers -- Access control
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10796 , http://hdl.handle.net/10948/68 , Electronic data processing departments -- Security measures , Computers -- Access control
- Description: The increasing reliance on information technology to support business processes has emphasised the need for information security mechanisms. This, however, has resulted in an ever-increasing workload in terms of security administration. Security administration encompasses the activity of ensuring the correct enforcement of access control within an organisation. Access rights and their allocation are dictated by the security policies within an organisation. As such, security administration can be seen as a policybased approach. Policy-based approaches promise to lighten the workload of security administrators. Separation of duties is one of the principles cited as a criterion when setting up these policy-based mechanisms. Different types of separation of duty policies exist. They can be categorised into policies that can be enforced at administration time, viz. static separation of duty requirements and policies that can be enforced only at execution time, viz. dynamic separation of duty requirements. This dissertation deals with the specification of both static separation of duty requirements and dynamic separation of duty requirements in role-based workflow environments. It proposes a model for the specification of separation of duty requirements, the expressions of which are based on set theory. The model focuses, furthermore, on the enforcement of static separation of duty. The enforcement of static separation of duty requirements is modelled in terms of invariant conditions. The invariant conditions specify restrictions upon the elements allowed in the sets representing access control requirements. The sets are themselves expressed as database tables within a relational database management system. Algorithms that stipulate how to verify the additions or deletions of elements within these sets can then be performed within the database management system. A prototype was developed in order to demonstrate the concepts of this model. This prototype helps demonstrate how the proposed model could function and flaunts its effectiveness.
- Full Text:
- Date Issued: 2001
- Authors: Perelson, Stephen
- Date: 2001
- Subjects: Electronic data processing departments -- Security measures , Computers -- Access control
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10796 , http://hdl.handle.net/10948/68 , Electronic data processing departments -- Security measures , Computers -- Access control
- Description: The increasing reliance on information technology to support business processes has emphasised the need for information security mechanisms. This, however, has resulted in an ever-increasing workload in terms of security administration. Security administration encompasses the activity of ensuring the correct enforcement of access control within an organisation. Access rights and their allocation are dictated by the security policies within an organisation. As such, security administration can be seen as a policybased approach. Policy-based approaches promise to lighten the workload of security administrators. Separation of duties is one of the principles cited as a criterion when setting up these policy-based mechanisms. Different types of separation of duty policies exist. They can be categorised into policies that can be enforced at administration time, viz. static separation of duty requirements and policies that can be enforced only at execution time, viz. dynamic separation of duty requirements. This dissertation deals with the specification of both static separation of duty requirements and dynamic separation of duty requirements in role-based workflow environments. It proposes a model for the specification of separation of duty requirements, the expressions of which are based on set theory. The model focuses, furthermore, on the enforcement of static separation of duty. The enforcement of static separation of duty requirements is modelled in terms of invariant conditions. The invariant conditions specify restrictions upon the elements allowed in the sets representing access control requirements. The sets are themselves expressed as database tables within a relational database management system. Algorithms that stipulate how to verify the additions or deletions of elements within these sets can then be performed within the database management system. A prototype was developed in order to demonstrate the concepts of this model. This prototype helps demonstrate how the proposed model could function and flaunts its effectiveness.
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- Date Issued: 2001