Salimata
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125510 , vital:35790 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-04
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125510 , vital:35790 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-04
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
Djanfa
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Popular music--Mali--1991-2000 , Guitar , Drum--Performance , Djembe music , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125469 , vital:35786 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-01
- Description: Malian popular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Popular music--Mali--1991-2000 , Guitar , Drum--Performance , Djembe music , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125469 , vital:35786 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-01
- Description: Malian popular music
- Full Text: false
- Date Issued: 1999
Sanga
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125520 , vital:35792 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-06
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125520 , vital:35792 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-06
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
Dankorobo
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Men's chorus , Mixed chorus , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125478 , vital:35787 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-02
- Description: Malian traditional music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Men's chorus , Mixed chorus , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125478 , vital:35787 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-02
- Description: Malian traditional music
- Full Text: false
- Date Issued: 1999
Agwa
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125568 , vital:35796 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-08
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125568 , vital:35796 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-08
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
Naniba
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125515 , vital:35791 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-05
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125515 , vital:35791 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-05
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
Yerewolo
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Drum , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125487 , vital:35788 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-03
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Choral music , Drum , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125487 , vital:35788 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-03
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
Yallo
- Koniba Traore (author, composer, interpreter, performer), Straun Douglas
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125537 , vital:35794 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-07
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
- Authors: Koniba Traore (author, composer, interpreter, performer) , Straun Douglas
- Date: 1999
- Subjects: Band music , Popular music--Mali--1991-2000 , Africa Mali Bamako f-ml
- Language: Bambara
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/125537 , vital:35794 , International Library of African Music, Rhodes University, Grahamstown, South Africa , SDCO1-07
- Description: Malian polular music
- Full Text: false
- Date Issued: 1999
A pilot study of the use of groupwork in biology education at the Griffiths Mxenge College of Education : a research project ; Towards an effective implementation of assessment of biology practical work under ʺcurriculum 2005ʺ
- Authors: Kwayisi, Frederick Ntow
- Date: 1999
- Subjects: Biology -- Study and teaching -- South Africa Group work in education Biology -- Curricula Curriculum change -- South Africa Curriculum planning -- South Africa Competency-based education -- South Africa Inclusive education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1705 , http://hdl.handle.net/10962/d1003588
- Description: A pilot study of the use of groupwork in biology education at the Griffiths Mxenge College of Education: The Government of National Unity in 1994 introduced a new educational policy for the country. This represented a shift in paradigm from a transmission mode of teaching and learning to learner-centered education. The shift marks a transformation from a contentbased curriculum to an outcomes based education (aBE). aBE, which is underpinned by Constructivism and Social Constructivism advocates for the use of groupwork as a strategy for achieving the outcomes envisaged in our learners. The challenge facing teachers and educators is how to implement outcomes based education. The intention of this research is therefore to serve as a pilot project to find out about how groupwork may be used in teaching. It looks at types of groups, considerations a teacher should have in forming groups, dynamics which come into play during teaching and gives suggestions as to how groupwork problems may be solved. Others issued are also raised which were not fully covered in the research. It is the hope of the researcher that the project would be a basis for further research on the use of group work in teaching under outcomes based education. Towards an effective implementation of assessment of biology practical work under "curriculum 2005" Transformation taking place in education in the Republic of South Africa has implications for assessment. It involves a move away from the transmission mode of teaching and learning, to a learner-centered education with the attainment of outcomes. It is a move away from the summative mode of assessment to a formative mode, where assessment leads to the development of the learner and monitor and support teaching and learning. Questions arise as to what to assess, how, when to assess and by whom? This research project is an initial attempt to look at how this assessment policy may be implemented effectively in schools and colleges, using the teaching and learning of practical biology as a tool. It looks at examples of assessment methods that may be used to assess learners work, their functions and problems that may arise in the teachers attempt to transform hislher practices. Suggestions are made on factors to consider in implementing assessment practice and how problems, which may arise in assessment, may be overcome.
- Full Text:
- Date Issued: 1999
- Authors: Kwayisi, Frederick Ntow
- Date: 1999
- Subjects: Biology -- Study and teaching -- South Africa Group work in education Biology -- Curricula Curriculum change -- South Africa Curriculum planning -- South Africa Competency-based education -- South Africa Inclusive education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1705 , http://hdl.handle.net/10962/d1003588
- Description: A pilot study of the use of groupwork in biology education at the Griffiths Mxenge College of Education: The Government of National Unity in 1994 introduced a new educational policy for the country. This represented a shift in paradigm from a transmission mode of teaching and learning to learner-centered education. The shift marks a transformation from a contentbased curriculum to an outcomes based education (aBE). aBE, which is underpinned by Constructivism and Social Constructivism advocates for the use of groupwork as a strategy for achieving the outcomes envisaged in our learners. The challenge facing teachers and educators is how to implement outcomes based education. The intention of this research is therefore to serve as a pilot project to find out about how groupwork may be used in teaching. It looks at types of groups, considerations a teacher should have in forming groups, dynamics which come into play during teaching and gives suggestions as to how groupwork problems may be solved. Others issued are also raised which were not fully covered in the research. It is the hope of the researcher that the project would be a basis for further research on the use of group work in teaching under outcomes based education. Towards an effective implementation of assessment of biology practical work under "curriculum 2005" Transformation taking place in education in the Republic of South Africa has implications for assessment. It involves a move away from the transmission mode of teaching and learning, to a learner-centered education with the attainment of outcomes. It is a move away from the summative mode of assessment to a formative mode, where assessment leads to the development of the learner and monitor and support teaching and learning. Questions arise as to what to assess, how, when to assess and by whom? This research project is an initial attempt to look at how this assessment policy may be implemented effectively in schools and colleges, using the teaching and learning of practical biology as a tool. It looks at examples of assessment methods that may be used to assess learners work, their functions and problems that may arise in the teachers attempt to transform hislher practices. Suggestions are made on factors to consider in implementing assessment practice and how problems, which may arise in assessment, may be overcome.
- Full Text:
- Date Issued: 1999
Adsorptive cathodic stripping voltammetric determination of gold (III) in the presence of yeast mannan
- Lack, Barbara, Duncan, John, Nyokong, Tebello
- Authors: Lack, Barbara , Duncan, John , Nyokong, Tebello
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293151 , vital:57060 , xlink:href="https://doi.org/10.1016/S0003-2670(98)00736-3"
- Description: Adsorptive cathodic stripping voltammetric (AdCSV) studies of gold(III) on a glassy carbon electrode and in the presence of yeast mannan are reported. These studies give evidence of the formation of a complex between gold(III) and mannan in acid media as judged by the enhancement in the AdCSV currents and shift in the reduction peak of gold(III) in the presence of mannan. The AdCSV currents were linearly dependent on gold(III) concentrations ranging from 7.0 × 10−7 to 3.0 × 10−4 mol dm−3. A detection limit of 6.0 × 10−8 mol dm−3 was obtained. Interferences of copper(II) were observed in the presence of mannan, but there was no significant interference of silver(I).
- Full Text:
- Date Issued: 1999
- Authors: Lack, Barbara , Duncan, John , Nyokong, Tebello
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293151 , vital:57060 , xlink:href="https://doi.org/10.1016/S0003-2670(98)00736-3"
- Description: Adsorptive cathodic stripping voltammetric (AdCSV) studies of gold(III) on a glassy carbon electrode and in the presence of yeast mannan are reported. These studies give evidence of the formation of a complex between gold(III) and mannan in acid media as judged by the enhancement in the AdCSV currents and shift in the reduction peak of gold(III) in the presence of mannan. The AdCSV currents were linearly dependent on gold(III) concentrations ranging from 7.0 × 10−7 to 3.0 × 10−4 mol dm−3. A detection limit of 6.0 × 10−8 mol dm−3 was obtained. Interferences of copper(II) were observed in the presence of mannan, but there was no significant interference of silver(I).
- Full Text:
- Date Issued: 1999
Electrochemical studies of gold bioaccumulation by yeast cell wall components
- Authors: Lack, Barbara Anne
- Date: 1999
- Subjects: Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4311 , http://hdl.handle.net/10962/d1004969 , Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Description: Gold, amongst other group 11 metals, was almost certainly one of the first three metals known to man. In addition to the economic importance of the metal, gold has a wide variety of applications in the medical, electrocatalytical and micro-electronics fields. However, the determination of gold ions in solution, with accuracy, precision, sensitivity and selectivity is still an interesting and much debated topic in analytical chemistry. A system whereby gold ions have been successfully detected employing an electrochemical technique, known as stripping voltammetry, has been developed. The electrochemical method was chosen over other available techniques for the sensitivity, particularly at low concentrations, and selectivity properties; notably in the presence of other metal ions. Under acidic conditions, the electrochemical technique was applied and the presence of gold(III), at a concentration of 2.53 x 10⁻⁵ mol dm⁻³ in a mine waste water sample, was detected. Biomass, in particular yeast and algal types, have been successfully employed in extracting low concentrations of gold ions from industrial effluents. The manipulation of the biological facility for mineral interaction, biohydrometallurgy, may yield numerous potential new technologies. South Africa in particular would benefit from this area of research, since the country is a major ore and metal refining country and if the output and the efficiency of the mines could be improved, even by a small percentage, the financial rewards would be vast. In this study, the application of adsorptive cathodic stripping voltammetry (AdCSV) of gold(III) in the presence of various Saccharomyces cerevisiae cell wall components, was investigated to determine which, if any, were involved specifically in the chemical binding of the gold ions. The chitin and mannan extracts showed the most promise with detection limits of 1.10 x 10⁻⁶ mol dm⁻³ and 9 x 10⁻⁹ mol dm⁻³, respectively; employing the AdCSV technique. A modification of the stripping voltammetry technique, Osteryoung square wave stripping voltammetry (OSWSV), provided the lowest detection limit, for gold(IIl) in the presence of mannan, of 1.70 x 10⁻¹¹ mol dm⁻³ ; utilising a modified carbon paste electrode. The detection of gold(III) has been shown to be dependent on the type of electrode employed, the electrolyte solution and the presence of interfering agents. The effect of copper(II) and silver(I) on the detection of the gold(III) in solution was investigated; whilst the silver(I) has shown no detrimental effects on gold (III) detection systems, copper(II) has indicated the possibility of forming an inter-metallic compound with the gold(III). However, mannan has shown to selectively and preferentially bind the gold(III) in the presence of a ten-fold excess of copper(II). Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, as well as computer modelling techniques were employed to further investIgate the mannan-gold(III) interaction and proposed complex formed. The NMR, IR and computer modelling data are in agreement with the electrochemical data on proposing a mannan-gold(III) complex. The co-ordination site was established to be in the vicinity of the H-I and H-2 protons and the gold(III) adopts a square-planar geometry upon co-ordination. The benefits of the research are useful from a biological perspective (i. e. as more is known about the binding sites, microbiologists/biochemists may work on the optimisation of parameters for these sites or work could be furthered into the enhanced expression of the sites) and an industrial one. In addition to the' two major benefits, an improved understanding of gold and its chemistry would be achieved, which is advantageous for other fields of research as well.
- Full Text:
- Date Issued: 1999
- Authors: Lack, Barbara Anne
- Date: 1999
- Subjects: Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4311 , http://hdl.handle.net/10962/d1004969 , Hydrometallurgy , Electrochemical analysis , Gold ores , Gold
- Description: Gold, amongst other group 11 metals, was almost certainly one of the first three metals known to man. In addition to the economic importance of the metal, gold has a wide variety of applications in the medical, electrocatalytical and micro-electronics fields. However, the determination of gold ions in solution, with accuracy, precision, sensitivity and selectivity is still an interesting and much debated topic in analytical chemistry. A system whereby gold ions have been successfully detected employing an electrochemical technique, known as stripping voltammetry, has been developed. The electrochemical method was chosen over other available techniques for the sensitivity, particularly at low concentrations, and selectivity properties; notably in the presence of other metal ions. Under acidic conditions, the electrochemical technique was applied and the presence of gold(III), at a concentration of 2.53 x 10⁻⁵ mol dm⁻³ in a mine waste water sample, was detected. Biomass, in particular yeast and algal types, have been successfully employed in extracting low concentrations of gold ions from industrial effluents. The manipulation of the biological facility for mineral interaction, biohydrometallurgy, may yield numerous potential new technologies. South Africa in particular would benefit from this area of research, since the country is a major ore and metal refining country and if the output and the efficiency of the mines could be improved, even by a small percentage, the financial rewards would be vast. In this study, the application of adsorptive cathodic stripping voltammetry (AdCSV) of gold(III) in the presence of various Saccharomyces cerevisiae cell wall components, was investigated to determine which, if any, were involved specifically in the chemical binding of the gold ions. The chitin and mannan extracts showed the most promise with detection limits of 1.10 x 10⁻⁶ mol dm⁻³ and 9 x 10⁻⁹ mol dm⁻³, respectively; employing the AdCSV technique. A modification of the stripping voltammetry technique, Osteryoung square wave stripping voltammetry (OSWSV), provided the lowest detection limit, for gold(IIl) in the presence of mannan, of 1.70 x 10⁻¹¹ mol dm⁻³ ; utilising a modified carbon paste electrode. The detection of gold(III) has been shown to be dependent on the type of electrode employed, the electrolyte solution and the presence of interfering agents. The effect of copper(II) and silver(I) on the detection of the gold(III) in solution was investigated; whilst the silver(I) has shown no detrimental effects on gold (III) detection systems, copper(II) has indicated the possibility of forming an inter-metallic compound with the gold(III). However, mannan has shown to selectively and preferentially bind the gold(III) in the presence of a ten-fold excess of copper(II). Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, as well as computer modelling techniques were employed to further investIgate the mannan-gold(III) interaction and proposed complex formed. The NMR, IR and computer modelling data are in agreement with the electrochemical data on proposing a mannan-gold(III) complex. The co-ordination site was established to be in the vicinity of the H-I and H-2 protons and the gold(III) adopts a square-planar geometry upon co-ordination. The benefits of the research are useful from a biological perspective (i. e. as more is known about the binding sites, microbiologists/biochemists may work on the optimisation of parameters for these sites or work could be furthered into the enhanced expression of the sites) and an industrial one. In addition to the' two major benefits, an improved understanding of gold and its chemistry would be achieved, which is advantageous for other fields of research as well.
- Full Text:
- Date Issued: 1999
An investigation into the use of IEEE 1394 for audio and control data distribution in music studio environments
- Authors: Laubscher, Robert Alan
- Date: 1999 , 2011-11-10
- Subjects: Digital electronics , Sound -- Recording and reproducing -- Digital techniques , MIDI (Standard) , Music -- Data processing , Computer sound processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4619 , http://hdl.handle.net/10962/d1006483 , Digital electronics , Sound -- Recording and reproducing -- Digital techniques , MIDI (Standard) , Music -- Data processing , Computer sound processing
- Description: This thesis investigates the feasibility of using a new digital interconnection technology, the IEEE-1394 High Performance Serial Bus, for audio and control data distribution in local and remote music recording studio environments. Current methods for connecting studio devices are described, and the need for a new digital interconnection technology explained. It is shown how this new interconnection technology and developing protocol standards make provision for multi-channel audio and control data distribution, routing, copyright protection, and device synchronisation. Feasibility is demonstrated by the implementation of a custom hardware and software solution. Remote music studio connectivity is considered, and the emerging standards and technologies for connecting future music studio utilising this new technology are discussed. , Microsoft Word , Adobe Acrobat 9.46 Paper Capture Plug-in
- Full Text:
- Date Issued: 1999
- Authors: Laubscher, Robert Alan
- Date: 1999 , 2011-11-10
- Subjects: Digital electronics , Sound -- Recording and reproducing -- Digital techniques , MIDI (Standard) , Music -- Data processing , Computer sound processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4619 , http://hdl.handle.net/10962/d1006483 , Digital electronics , Sound -- Recording and reproducing -- Digital techniques , MIDI (Standard) , Music -- Data processing , Computer sound processing
- Description: This thesis investigates the feasibility of using a new digital interconnection technology, the IEEE-1394 High Performance Serial Bus, for audio and control data distribution in local and remote music recording studio environments. Current methods for connecting studio devices are described, and the need for a new digital interconnection technology explained. It is shown how this new interconnection technology and developing protocol standards make provision for multi-channel audio and control data distribution, routing, copyright protection, and device synchronisation. Feasibility is demonstrated by the implementation of a custom hardware and software solution. Remote music studio connectivity is considered, and the emerging standards and technologies for connecting future music studio utilising this new technology are discussed. , Microsoft Word , Adobe Acrobat 9.46 Paper Capture Plug-in
- Full Text:
- Date Issued: 1999
Research portfolio : environmental education
- Authors: Le Roux, Kim
- Date: 1999
- Subjects: Environmental education -- South Africa , Environmental education -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1738 , http://hdl.handle.net/10962/d1003622
- Full Text:
- Date Issued: 1999
- Authors: Le Roux, Kim
- Date: 1999
- Subjects: Environmental education -- South Africa , Environmental education -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1738 , http://hdl.handle.net/10962/d1003622
- Full Text:
- Date Issued: 1999
Seeking health: the hierarchy of resort in utilisation patterns of traditional and western medicine in multi-cultural Katutura, Namibia
- Authors: LeBeau, Debie
- Date: 1999
- Subjects: Traditional medicine -- Namibia -- Katutura (Windhoek) Social medicine -- Namibia -- History Traditional medicine -- Social aspects -- Namibia -- History Medical anthropology -- Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2103 , http://hdl.handle.net/10962/d1002666
- Description: This thesis examines health care choices patients make when illness and misfortune occur. Research on health seeking behaviour was conducted in Katutura (the African township outside of Windhoek in Namibia) during 1996 and 1997. Due to the availability of a wide range of health care options from both the western and the traditional medical systems, utilisation of traditional medicine represents a conscious choice by patients and is not due to a lack of other alternatives. The use of traditional medicine can therefore be attributed to social, cultural, and personal factors rather than access, cost, and distance to modern health care facilities. A set of theoretical postulates is constructed to explain health seeking behaviour, including western and African concepts of ill health, which integrates both macro and micro-level analysis. Through macro-level analysis, this model postulates that western and traditional medical systems are able to exist within a single society due to the presence of co-existing ideologies (Medical Systems Theory). This model further postulates that social change is a significant attribute of post-colonial Namibian society (Post-colonial Theory). Rapid social change causes social disequilibrium leading to insecurities within the population which increase traditional health care utilisation, especially due to witchcraft accusation. Thus, macro-level theories are used to explain the existence and form of health care alternatives in Katutura; while micro-level analysis is used to examine how people make rational health care choices based on individualised variables within the enabling and constraining umbrella of Namibia's social structure. These variables include the individual's means, goals, desires, and environment of physical and social objects. Health seeking behaviour is influenced by the individual's previous experiences (history), personal constraints, and access to information. Based on data from the 1996 Tradition and Health Survey administered as part of the research for this dissertation, a model for health seeking behaviour is developed to guide the analysis of qualitative data. This model postulates that different patterns of utilisation depend on perceived causes, reasons and origins (aetiology) as well as manifestations of illness. Some illnesses are perceived of as clearly African and some are seen to be clearly western (both of these perceptions result in a single utilisation pattern). Some illnesses have a social/spiritual aetiology but universally recognised manifestations (resulting in a simultaneous utilisation pattern), and some illnesses are of indeterminate aetiology until treatment begins (resulting in a multi-faceted utilisation pattern). In addition to a utilisation pattern based on the aetiology and manifestation of illness, previous health seeking experiences influence, to a certain extent, subsequent health care choices; whereby the failure of one medical system to produce satisfactory results can cause health seekers to shift to another treatment regimen. In Katutura choices patients make are also influenced, to a certain extent, by the urban nature of the health seeking environment. Urban patients seek traditional medicine for a range of social/spiritual aetiologies, due to rapid social change and the experience of new and threatening situations. Urban patients also have more knowledge and experience with the western concept of contagious transmission as opposed to the traditional concept of social/spiritual contamination. In addition, health seeking patterns vary slightly between the different ethnic groups in Katutura. Traditional aetiological beliefs of the different ethnic groups in Katutura are reflected in current cultural beliefs about the cause of illness.
- Full Text:
- Date Issued: 1999
- Authors: LeBeau, Debie
- Date: 1999
- Subjects: Traditional medicine -- Namibia -- Katutura (Windhoek) Social medicine -- Namibia -- History Traditional medicine -- Social aspects -- Namibia -- History Medical anthropology -- Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2103 , http://hdl.handle.net/10962/d1002666
- Description: This thesis examines health care choices patients make when illness and misfortune occur. Research on health seeking behaviour was conducted in Katutura (the African township outside of Windhoek in Namibia) during 1996 and 1997. Due to the availability of a wide range of health care options from both the western and the traditional medical systems, utilisation of traditional medicine represents a conscious choice by patients and is not due to a lack of other alternatives. The use of traditional medicine can therefore be attributed to social, cultural, and personal factors rather than access, cost, and distance to modern health care facilities. A set of theoretical postulates is constructed to explain health seeking behaviour, including western and African concepts of ill health, which integrates both macro and micro-level analysis. Through macro-level analysis, this model postulates that western and traditional medical systems are able to exist within a single society due to the presence of co-existing ideologies (Medical Systems Theory). This model further postulates that social change is a significant attribute of post-colonial Namibian society (Post-colonial Theory). Rapid social change causes social disequilibrium leading to insecurities within the population which increase traditional health care utilisation, especially due to witchcraft accusation. Thus, macro-level theories are used to explain the existence and form of health care alternatives in Katutura; while micro-level analysis is used to examine how people make rational health care choices based on individualised variables within the enabling and constraining umbrella of Namibia's social structure. These variables include the individual's means, goals, desires, and environment of physical and social objects. Health seeking behaviour is influenced by the individual's previous experiences (history), personal constraints, and access to information. Based on data from the 1996 Tradition and Health Survey administered as part of the research for this dissertation, a model for health seeking behaviour is developed to guide the analysis of qualitative data. This model postulates that different patterns of utilisation depend on perceived causes, reasons and origins (aetiology) as well as manifestations of illness. Some illnesses are perceived of as clearly African and some are seen to be clearly western (both of these perceptions result in a single utilisation pattern). Some illnesses have a social/spiritual aetiology but universally recognised manifestations (resulting in a simultaneous utilisation pattern), and some illnesses are of indeterminate aetiology until treatment begins (resulting in a multi-faceted utilisation pattern). In addition to a utilisation pattern based on the aetiology and manifestation of illness, previous health seeking experiences influence, to a certain extent, subsequent health care choices; whereby the failure of one medical system to produce satisfactory results can cause health seekers to shift to another treatment regimen. In Katutura choices patients make are also influenced, to a certain extent, by the urban nature of the health seeking environment. Urban patients seek traditional medicine for a range of social/spiritual aetiologies, due to rapid social change and the experience of new and threatening situations. Urban patients also have more knowledge and experience with the western concept of contagious transmission as opposed to the traditional concept of social/spiritual contamination. In addition, health seeking patterns vary slightly between the different ethnic groups in Katutura. Traditional aetiological beliefs of the different ethnic groups in Katutura are reflected in current cultural beliefs about the cause of illness.
- Full Text:
- Date Issued: 1999
Development and characterisation of a membrane gradostat bioreactor for the bioremediation of aromatic pollutants using white rot fungi
- Authors: Leukes, W
- Date: 1999
- Subjects: Aromatic compounds Pollutants Fungi Bioremediation Industrial microbiology Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4032 , http://hdl.handle.net/10962/d1004092
- Description: Bioremediation of aromatic pollutants using the ligninolytic enzymes of the white rot fungi has been thoroughly researched and has been shown to have considerable potential for industrial application. However, little success in scale-up and industrialisation of this technology has been attained due to problems associated with the continuous production of the pollutant-degrading enzymes using conventional bioreactor systems. The low productivities reported result from the incompatibility of conventional submerged culture reactor techniques with the physiological requirements of these fungi which have evolved on a solid-air interface, viz. wood. The enzymes are also produced only during the stationary phase of growth and can therefore be regarded as secondary metabolites. This study reports the conceptualisation, characterisation and evaluation of a novel bioreactor system as a solution to the continuous production of idiophasic pollutant degrading enzymes by the white rot fungus Phanerochaete chlysosporium. The reactor concept evolved from observation of these fungi in their native state, i. e. the metabolism of lignocellulosic material and involves the immobilisation of the organism onto a capillary ultrafiltration membrane. Nutrient gradients established across the biofilm, an inherent characteristic of fixed bed perfusion reactors, are exploited to provide both nutrient rich and nutrient poor zones across the biofilm. This allows growth or primary metabolism in the nutrient rich zone, pushing older biomass into the nutrient poor zone where secondary metabolism is induced by nutrient starvation. In effect, this represents a transformation of the events of a batch culture from a temporal to a spatial domain, allowing continuous production of secondary metabolites over time. Direct contact of the outer part of the biofilm with an air stream simulated the solid-air interface of the native state of the fungus. In order to facilitate the practical application of the membrane gradostat reactor (MGR) concept, conventional capillary membranes and membrane bioreactor modules were first evaluated. These were found to be unsuitable for application of the MGR concept. However, critical analysis of the shortcomings of the conventional systems resulted in the formulation of a set of design criteria for the development of a suitable membrane and module. These design criteria were satisfied by the development of a novel capillary membrane for membrane bioreactors, as well as a transverse flow membrane module, which is a novel approach in membrane bioreactor configuration. For the physiological characterisation of the MGR concept, a single fibre bioreactor unit was designed, which allowed destructive sampling of the biofilm for analysis. Using this system, it was shown that distinct morphological zones could be observed radially across the mature biofilm obtained through MGR operation. That these morphotypes do represent the temporal events of a typical batch culture in a spatial domain was confirmed by following the morphological changes occurring during batch culture of the immobilised fungus where the onset of primary and secondary metabolic conditions were manipulated through control of the nutrient supply. The different morphotypes were correlated to distinct growth phases by comparison of the morphology to the secretion of known enzymatic markers for secondary metabolism, viz. succinate dehydrogenase and cytochrome C oxidoreductase. Detailed structure-function analysis of the biofilm using transmission electron microscopy and adapted enzyme cytochemical staining techniques showed that the biofilm appeared to operate as a co-ordinated unit, with primary and secondary metabolism apparently linked in one thallus through nutrient translocation. This study provided new insights into the physiology of P. chrysosp,o rium and a detailed descriptive model was formulated which correlates well to existing models of wood degradation by the white rot fungi (WRF). Evaluation of the process on a laboratory scale using a novel transverse flow membrane bioreactor showed that a volumetric productivity of 1916 U.L.⁻¹day⁻¹ for manganese peroxidase, one of the pollutant degrading enzymes, could be attained, corresponding to a final concentration of 2 361 U.L.⁻¹ This may be compared to the best reported system (Moreira el at. 1997), where a volumetric productivity of 202 U.L.⁻¹day⁻¹was achieved with a final concentration of 250 U.L.⁻¹ However, MGR productivity is yet to be subjected to rigorous optimisation studies. The process could be operated continuously for 60 days. However, peak productivity could not be maintained for long periods. This was found to be due to physical phenomena relating to the fluid dynamics of the system which caused fluid flow maldistribution, which would have to be resolved through engineering analysis. In evaluation of the MGR concept for aromatic pollutant removal, in this case ρ- cresol, from growth medium, good performance was also achieved. The VmaxKm calculated by linear regression for the MGR was 0.8 (R² = 0.93), which compared favourably to that reported by Lewandowski et al. (1990), who obtained a Vmax/Km of 0.34 for a packed bed reactor treating chlorophenol. It was concluded that the MGR showed suitable potential to warrant further development, and that the descriptive characterisation of the biofilm physiology provided a sufficient basis for process analysis once engineering aspects ofthe system could be resolved.
- Full Text:
- Date Issued: 1999
- Authors: Leukes, W
- Date: 1999
- Subjects: Aromatic compounds Pollutants Fungi Bioremediation Industrial microbiology Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4032 , http://hdl.handle.net/10962/d1004092
- Description: Bioremediation of aromatic pollutants using the ligninolytic enzymes of the white rot fungi has been thoroughly researched and has been shown to have considerable potential for industrial application. However, little success in scale-up and industrialisation of this technology has been attained due to problems associated with the continuous production of the pollutant-degrading enzymes using conventional bioreactor systems. The low productivities reported result from the incompatibility of conventional submerged culture reactor techniques with the physiological requirements of these fungi which have evolved on a solid-air interface, viz. wood. The enzymes are also produced only during the stationary phase of growth and can therefore be regarded as secondary metabolites. This study reports the conceptualisation, characterisation and evaluation of a novel bioreactor system as a solution to the continuous production of idiophasic pollutant degrading enzymes by the white rot fungus Phanerochaete chlysosporium. The reactor concept evolved from observation of these fungi in their native state, i. e. the metabolism of lignocellulosic material and involves the immobilisation of the organism onto a capillary ultrafiltration membrane. Nutrient gradients established across the biofilm, an inherent characteristic of fixed bed perfusion reactors, are exploited to provide both nutrient rich and nutrient poor zones across the biofilm. This allows growth or primary metabolism in the nutrient rich zone, pushing older biomass into the nutrient poor zone where secondary metabolism is induced by nutrient starvation. In effect, this represents a transformation of the events of a batch culture from a temporal to a spatial domain, allowing continuous production of secondary metabolites over time. Direct contact of the outer part of the biofilm with an air stream simulated the solid-air interface of the native state of the fungus. In order to facilitate the practical application of the membrane gradostat reactor (MGR) concept, conventional capillary membranes and membrane bioreactor modules were first evaluated. These were found to be unsuitable for application of the MGR concept. However, critical analysis of the shortcomings of the conventional systems resulted in the formulation of a set of design criteria for the development of a suitable membrane and module. These design criteria were satisfied by the development of a novel capillary membrane for membrane bioreactors, as well as a transverse flow membrane module, which is a novel approach in membrane bioreactor configuration. For the physiological characterisation of the MGR concept, a single fibre bioreactor unit was designed, which allowed destructive sampling of the biofilm for analysis. Using this system, it was shown that distinct morphological zones could be observed radially across the mature biofilm obtained through MGR operation. That these morphotypes do represent the temporal events of a typical batch culture in a spatial domain was confirmed by following the morphological changes occurring during batch culture of the immobilised fungus where the onset of primary and secondary metabolic conditions were manipulated through control of the nutrient supply. The different morphotypes were correlated to distinct growth phases by comparison of the morphology to the secretion of known enzymatic markers for secondary metabolism, viz. succinate dehydrogenase and cytochrome C oxidoreductase. Detailed structure-function analysis of the biofilm using transmission electron microscopy and adapted enzyme cytochemical staining techniques showed that the biofilm appeared to operate as a co-ordinated unit, with primary and secondary metabolism apparently linked in one thallus through nutrient translocation. This study provided new insights into the physiology of P. chrysosp,o rium and a detailed descriptive model was formulated which correlates well to existing models of wood degradation by the white rot fungi (WRF). Evaluation of the process on a laboratory scale using a novel transverse flow membrane bioreactor showed that a volumetric productivity of 1916 U.L.⁻¹day⁻¹ for manganese peroxidase, one of the pollutant degrading enzymes, could be attained, corresponding to a final concentration of 2 361 U.L.⁻¹ This may be compared to the best reported system (Moreira el at. 1997), where a volumetric productivity of 202 U.L.⁻¹day⁻¹was achieved with a final concentration of 250 U.L.⁻¹ However, MGR productivity is yet to be subjected to rigorous optimisation studies. The process could be operated continuously for 60 days. However, peak productivity could not be maintained for long periods. This was found to be due to physical phenomena relating to the fluid dynamics of the system which caused fluid flow maldistribution, which would have to be resolved through engineering analysis. In evaluation of the MGR concept for aromatic pollutant removal, in this case ρ- cresol, from growth medium, good performance was also achieved. The VmaxKm calculated by linear regression for the MGR was 0.8 (R² = 0.93), which compared favourably to that reported by Lewandowski et al. (1990), who obtained a Vmax/Km of 0.34 for a packed bed reactor treating chlorophenol. It was concluded that the MGR showed suitable potential to warrant further development, and that the descriptive characterisation of the biofilm physiology provided a sufficient basis for process analysis once engineering aspects ofthe system could be resolved.
- Full Text:
- Date Issued: 1999
New bells, new founder - Hillandale, South Africa
- Authors: Lewis, Colin A
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6163 , http://hdl.handle.net/10962/d1012350
- Description: On the afternoon of Sunday 2nd May 1999, the first ring of bells cast in Africa, the bells at Hillandale, were rung for the first time. This is the second ring of bells to be installed in an institution established by the Order of the Holy Cross, and the seventh ring in South Africa and the tenth ring in Africa. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1999
- Authors: Lewis, Colin A
- Date: 1999
- Language: English
- Type: Article
- Identifier: vital:6163 , http://hdl.handle.net/10962/d1012350
- Description: On the afternoon of Sunday 2nd May 1999, the first ring of bells cast in Africa, the bells at Hillandale, were rung for the first time. This is the second ring of bells to be installed in an institution established by the Order of the Holy Cross, and the seventh ring in South Africa and the tenth ring in Africa. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 1999
Electrochemical studies of metal-ligand interactions and of metal binding proteins
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Date Issued: 1999
- Authors: Limson, Janice Leigh
- Date: 1999
- Subjects: Electrochemical analysis , Metals -- Analysis , Proteins -- Analysis , Electrochemistry -- Technique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4551 , http://hdl.handle.net/10962/d1018239
- Description: Electrochemical methods were researched for the analysis of metals, proteins and the identification of metal binding proteins. Adsorptive cathodic stripping voltamrnetry for metal analysis combines the inherent sensitivity of electrochemical techniques with the specificity of ligands for the nonfaradaic preconcentration of analytes at the electrode. The utility of catechol, resorcinol, 4-methylcatechol and 4-t-butylcatechol as ligands was explored for the sensitive analysis of copper, bismuth, cadmium and lead on a mercury film glassy carbon electrode. Metal complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed the highest current responses with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper. The electroanalysis of cysteine and cysteine containing proteins at carbon electrodes are impaired by slow electron transfer rates at carbon electrodes, exhibiting high overpotentials, greater than 1 V vs Ag! Agel. Metallophthalocyanines have been shown to promote the electrocatalysis of cysteine at lowered potentials. Chemical modification of electrodes with appropriate modifiers is a means of incorporating specificity into electroanalysis, with applications in electrocatalysis. A glassy carbon electrode was modified by electrodeposition of cobalt (II) tetrasulphophthalocyanine [Co(II)TSPct to produce a chemically modified glassy carbon electrode (CMGCE). The CoTSPc-CMGCE catalysed the oxidation of cysteine in the pH range 1 to 10. The significance of this electrode is an application for analysis of proteins at biological pH's. A biscyanoruthenium(II) phthalocyanine CMGCE catalysed the oxidation of cysteine at 0.43 V vs Ag/AgCl a significant lowering in the overpotential for the oxidation of cysteine. Metallothionein, a metal binding protein, is believed to be involved in metal homeostasis and detoxification in the peripheral organs of living systems. A method for the quantitative determination of this protein utilising its high cysteine content was presented. At pH 8.4 Tris-HCl buffer, and using a CoTSPc-CMGCE modified by electrodeposition of the modifier, the anodic peaks for the oxidation of metallothionein was observed at 0. 90 V vs Ag/ AgCI. Ferredoxin is a simple iron-sulphur protein. One tenth of its residues are cysteine. Ferredoxin is involved in simple electron transfer processes during photosynthesis and respiration. Electrochemical studies of spinach ferredoxin were conducted at a CoTSPc-CMGCE. Anodic currents for the oxidation of the cysteine fragment of ferredoxin was observed at 0.85 V vs Ag/AgCl in HEPES buffer at pH 7.4, representing a new method for analysis of this protein. Voltammetric studies of its ferric/ferrous transition have shown quasi-reversible waves atE~ -0.62 V vs Ag/AgCl only in the presence of promoters. At a CoTSPc-CMGCE, a cathodic wave attributed to the reduction of Fe(III)/Fe(II) was observed at Epc -0.34 V vs Ag/AgCl. This represents an alternative method for voltammetric studies of the ferric/ferrous transition at significantly lowered potentials. Melatonin, a pineal gland hormone functions m setting and entraining circadian rhythms and in neuroprotection as a free radical scavenger and general antioxidant. Using adsorptive cathodic stripping voltammetry, the binding affinities of melatonin, serotonin and tryptophan for metals, were measured. The results showed that the following metal complexes were formed: aluminium with melatonin, serotonin and tryptophan; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron (III) with melatonin and serotonin; lead with melatonin, tryptophan and serotonin, zinc with melatonin and tryptophan and iron (II) with tryptophan. The studies suggest a further role for melatonin in the reduction of free radical generation and in metal detoxification and may explain the accumulation of aluminium in Alzheimer's disease.
- Full Text:
- Date Issued: 1999
Effects of zone and wave exposure on population structure and recruitment of the mussel (Perna perna) in South Africa
- Authors: Lindsay, Justin Robert
- Date: 1999
- Subjects: Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5685 , http://hdl.handle.net/10962/d1005371 , Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Description:
Certain aspects of the population dynamics of the brown mussel, Perna perna, were examined at 18 sites along the south coast of South African. Specifically the effects of wave exposure and tidal height were examined in relation to mussel size, biomass and density. A single set of samples was removed from each of the 18 sites, over three spring tide cycles. Sites were classified as exposed or sheltered prior to sampling. Principal component analysis (PCA) (based on mussel length data) and length frequency histograms revealed that there was a general decrease in the modal size of the adult mussel cohort with an increase in tidal height. The effects of exposure on mussel size decreased higher on the shore. On the exposed low shore the maximum size of mussels had a mean length of 102.3mm and was significantly larger (ANOVA, p<0.0001) than that for mussels on sheltered shores (86.7mm). The difference between mean maximum lengths of mussels on the mid shore was not so great, exposed sites had a average mean maximum length of 79.9, while on the sheltered shores it was 68.4mm. On the high shore the difference between the average mean maximum lengths at exposed and sheltered sites was only 3.9mm. The fact that the effects of exposure were greatest on the low shore was also borne out in the PCA. In this analysis low shore exposed and sheltered zones separated into two groups with little overlap, mid shore exposed and sheltered zones were positioned next to each other, and exposed and sheltered high shore zones were clumped together. Densities of adult mussels (>l5mm) were calculated as real densities from randomly placed quads i.e. not from areas of 100% cover. Density decreased up the shore; low, mid and high shore zones were significantly different from each other (ANOVA , p<0.0001; followed by multiple range tests). There was no significant difference between the densities of mussels at exposed and sheltered sites within each zone (ANOVA, p=0.7155). Recruit (
- Full Text:
- Date Issued: 1999
- Authors: Lindsay, Justin Robert
- Date: 1999
- Subjects: Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5685 , http://hdl.handle.net/10962/d1005371 , Perna -- South Africa , Perna -- Growth , Mussels -- South Africa
- Description:
Certain aspects of the population dynamics of the brown mussel, Perna perna, were examined at 18 sites along the south coast of South African. Specifically the effects of wave exposure and tidal height were examined in relation to mussel size, biomass and density. A single set of samples was removed from each of the 18 sites, over three spring tide cycles. Sites were classified as exposed or sheltered prior to sampling. Principal component analysis (PCA) (based on mussel length data) and length frequency histograms revealed that there was a general decrease in the modal size of the adult mussel cohort with an increase in tidal height. The effects of exposure on mussel size decreased higher on the shore. On the exposed low shore the maximum size of mussels had a mean length of 102.3mm and was significantly larger (ANOVA, p<0.0001) than that for mussels on sheltered shores (86.7mm). The difference between mean maximum lengths of mussels on the mid shore was not so great, exposed sites had a average mean maximum length of 79.9, while on the sheltered shores it was 68.4mm. On the high shore the difference between the average mean maximum lengths at exposed and sheltered sites was only 3.9mm. The fact that the effects of exposure were greatest on the low shore was also borne out in the PCA. In this analysis low shore exposed and sheltered zones separated into two groups with little overlap, mid shore exposed and sheltered zones were positioned next to each other, and exposed and sheltered high shore zones were clumped together. Densities of adult mussels (>l5mm) were calculated as real densities from randomly placed quads i.e. not from areas of 100% cover. Density decreased up the shore; low, mid and high shore zones were significantly different from each other (ANOVA , p<0.0001; followed by multiple range tests). There was no significant difference between the densities of mussels at exposed and sheltered sites within each zone (ANOVA, p=0.7155). Recruit (
- Full Text:
- Date Issued: 1999
Population dynamics and growth rates of the brown mussel (Perna perna) on wave exposed and wave sheltered shores of South Africa
- Authors: Lindsay, Tracy Lynn
- Date: 1999
- Subjects: Perna -- South Africa , Mussels -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5741 , http://hdl.handle.net/10962/d1005427 , Perna -- South Africa , Mussels -- South Africa
- Description:
Population dynamics of Perna perna in low shore mussel beds were investigated over a 15 month period at six sites along the south coast of South Africa, with particular reference to the effects of wave exposure. The degree of exposure was first quantitatively ascertained using the dissolution of cement blocks to measure average wave force and dynamometers to measure maximum wave force. The mean mass loss of the cement blocks was higher at Diaz Cross and Kwaai Hoek than at Mgwalana, Rufanes and Riet River. No data were available for Fish River. The mean maximum wave force encountered at Diaz Cross, Kwaai Hoek and Fish River was significantly higher (p
15 mm) were positively correlated with recruit densities (1-5 mm) for both shore types (p 15 mm) was significantly lower on exposed (mean of 3 348.m⁻²) than on sheltered shores (mean of 4 796.m⁻²) (p O.05). The effect of exposure on growth rate formed the focal point of this study and was determined using three different approaches. The first technique, mark-recapture, involved filing notches on the growing edges of mussels in the field. After 111 days, mussels were removed and the growth measured. The second approach used internal growth bands to measure growth rates, once the periodicity with which these bands were laid down was established. Thirdly, using Shepherd's length composition analysis (SLCA), growth rates were determined from length frequency distributions in 11 samples taken over 15 months. The general conclusion from all three approaches was that growth rate was twice as fast on the exposed shores as on the sheltered shores (p - Full Text:
- Date Issued: 1999
- Authors: Lindsay, Tracy Lynn
- Date: 1999
- Subjects: Perna -- South Africa , Mussels -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5741 , http://hdl.handle.net/10962/d1005427 , Perna -- South Africa , Mussels -- South Africa
- Description:
Population dynamics of Perna perna in low shore mussel beds were investigated over a 15 month period at six sites along the south coast of South Africa, with particular reference to the effects of wave exposure. The degree of exposure was first quantitatively ascertained using the dissolution of cement blocks to measure average wave force and dynamometers to measure maximum wave force. The mean mass loss of the cement blocks was higher at Diaz Cross and Kwaai Hoek than at Mgwalana, Rufanes and Riet River. No data were available for Fish River. The mean maximum wave force encountered at Diaz Cross, Kwaai Hoek and Fish River was significantly higher (p
15 mm) were positively correlated with recruit densities (1-5 mm) for both shore types (p 15 mm) was significantly lower on exposed (mean of 3 348.m⁻²) than on sheltered shores (mean of 4 796.m⁻²) (p O.05). The effect of exposure on growth rate formed the focal point of this study and was determined using three different approaches. The first technique, mark-recapture, involved filing notches on the growing edges of mussels in the field. After 111 days, mussels were removed and the growth measured. The second approach used internal growth bands to measure growth rates, once the periodicity with which these bands were laid down was established. Thirdly, using Shepherd's length composition analysis (SLCA), growth rates were determined from length frequency distributions in 11 samples taken over 15 months. The general conclusion from all three approaches was that growth rate was twice as fast on the exposed shores as on the sheltered shores (p - Full Text:
- Date Issued: 1999
Adaptive flow management of multimedia data with a variable quality of service
- Authors: Littlejohn, Paul Stephen
- Date: 1999
- Subjects: Multimedia systems , Multimedia systems -- Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4605 , http://hdl.handle.net/10962/d1004863 , Multimedia systems , Multimedia systems -- Evaluation
- Description: Much of the current research involving the delivery of multimedia data focuses on the need to maintain a constant Quality of Service (QoS) throughout the lifetime of the connection. Delivery of a constant QoS requires that a guaranteed bandwidth is available for the entire connection. Techniques, such as resource reservation, are able to provide for this. These approaches work well across networks that are fairly homogeneous, and which have sufficient resources to sustain the guarantees, but are not currently viable over either heterogeneous or unreliable networks. To cater for the great number of networks (including the Internet) which do not conform to the ideal conditions required by constant Quality of Service mechanisms, this thesis proposes a different approach, that of dynamically adjusting the QoS in response to changing network conditions. Instead of optimizing the Quality of Service, the approach used in this thesis seeks to ensure the delivery of the information, at the best possible quality, as determined by the carrying ability of the poorest segment in the network link. To illustrate and examine this model, a service-adaptive system is described, which allows for the streaming of multimedia audio data across a network using the RealTime Transport Protocol. This application continually adjusts its service requests in response to the current network conditions. A client/server model is outlined whereby the server attempts to provide scalable media content, in this case audio data, to a client at the highest possible Quality of Service. The thesis presents and evaluates a number of renegotiation methods for adjusting the Quality of Service between the client and server. An A djusted QoS renegotiation method algorithm is suggested, which delivers the best possible quality, within an acceptable loss boundary.
- Full Text:
- Date Issued: 1999
- Authors: Littlejohn, Paul Stephen
- Date: 1999
- Subjects: Multimedia systems , Multimedia systems -- Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4605 , http://hdl.handle.net/10962/d1004863 , Multimedia systems , Multimedia systems -- Evaluation
- Description: Much of the current research involving the delivery of multimedia data focuses on the need to maintain a constant Quality of Service (QoS) throughout the lifetime of the connection. Delivery of a constant QoS requires that a guaranteed bandwidth is available for the entire connection. Techniques, such as resource reservation, are able to provide for this. These approaches work well across networks that are fairly homogeneous, and which have sufficient resources to sustain the guarantees, but are not currently viable over either heterogeneous or unreliable networks. To cater for the great number of networks (including the Internet) which do not conform to the ideal conditions required by constant Quality of Service mechanisms, this thesis proposes a different approach, that of dynamically adjusting the QoS in response to changing network conditions. Instead of optimizing the Quality of Service, the approach used in this thesis seeks to ensure the delivery of the information, at the best possible quality, as determined by the carrying ability of the poorest segment in the network link. To illustrate and examine this model, a service-adaptive system is described, which allows for the streaming of multimedia audio data across a network using the RealTime Transport Protocol. This application continually adjusts its service requests in response to the current network conditions. A client/server model is outlined whereby the server attempts to provide scalable media content, in this case audio data, to a client at the highest possible Quality of Service. The thesis presents and evaluates a number of renegotiation methods for adjusting the Quality of Service between the client and server. An A djusted QoS renegotiation method algorithm is suggested, which delivers the best possible quality, within an acceptable loss boundary.
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- Date Issued: 1999