Nyokong wins Prestigious L'Oreal - Unesco Award for Woman in Science
- Authors: Peter, Kerry
- Language: English
- Type: Article
- Identifier: vital:7192 , http://hdl.handle.net/10962/d1006356
- Description: Rhodes University’s Professor Tebello Nyokong, has won the Africa-Arab State 2009 L’Oréal-Unesco Award for Women in Science for her pioneering research into photodynamic therapy which looks at harnessing light for cancer therapy and environmental clean-up. Nyokong is the third South African Scientist to receive this award, and reaffirms Rhodes’s place as one of the top research institutions in the country. University of Cape Town’s Professor Jennifer Thompson was previously recognised for her work on genetic engineering while Wits University’s Professor Valerie Mizrahi was recognised for her tuberculosis research.
- Full Text:
- Authors: Peter, Kerry
- Language: English
- Type: Article
- Identifier: vital:7192 , http://hdl.handle.net/10962/d1006356
- Description: Rhodes University’s Professor Tebello Nyokong, has won the Africa-Arab State 2009 L’Oréal-Unesco Award for Women in Science for her pioneering research into photodynamic therapy which looks at harnessing light for cancer therapy and environmental clean-up. Nyokong is the third South African Scientist to receive this award, and reaffirms Rhodes’s place as one of the top research institutions in the country. University of Cape Town’s Professor Jennifer Thompson was previously recognised for her work on genetic engineering while Wits University’s Professor Valerie Mizrahi was recognised for her tuberculosis research.
- Full Text:
Application of satellite-derived rainfall estimates to extend water resource simulation modelling in South Africa
- Sawunyama, Tendai, Hughes, Denis A
- Authors: Sawunyama, Tendai , Hughes, Denis A
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7089 , http://hdl.handle.net/10962/d1012419
- Description: Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.
- Full Text:
- Date Issued: 2008
- Authors: Sawunyama, Tendai , Hughes, Denis A
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7089 , http://hdl.handle.net/10962/d1012419
- Description: Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.
- Full Text:
- Date Issued: 2008
Written out, writing in : orature in the South African literary canon
- Authors: Seddon, Deborah Ann
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:2263 , http://hdl.handle.net/10962/d1004695
- Description: As described by Duncan Brown, South African orature represents "our truly original contribution to world literature" (Brown, Voicing the Text 1). This paper explores how orature might be successfully 'written into' the South African literary canon whilst promoting recognition of its existence as an oral form. My recent experiences of the difficulties, challenges, and benefits of teaching South African orature within the Rhodes University English department, have alerted me to the urgent need for the creation of a student- and teacher-friendly anthology which would collect, re-voice, and adequately contextualise a selection of the seminal works of South African oral poets from the colonial to the post-apartheid periods. Much of this poetry already exists in print-form but, despite an increasing recognition of oral poetry through a number of endeavours such the Poetry Africa Festival, the Lentswe Poetry Project on SABC 2, the Timbila Poetry Project and others, South African orature remains marginal in the country's literary canon. It is largely absent from the curriculum in the literature departments of its universities. The need to redress this situation is crucial, but the process of setting up and teaching an undergraduate course in South African oral poetry, while possible, is complicated. The works of our most important oral poets are scattered in a variety of books, libraries, and collections. The usual process of drawing up a booklist of set texts is undermined by the stark reality that many of the books are out of print. Fully giving voice to these texts is even harder to achieve - CD and video recordings of performances (if they exist at all) are not easily accessed or disseminated.
- Full Text:
- Date Issued: 2008
- Authors: Seddon, Deborah Ann
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:2263 , http://hdl.handle.net/10962/d1004695
- Description: As described by Duncan Brown, South African orature represents "our truly original contribution to world literature" (Brown, Voicing the Text 1). This paper explores how orature might be successfully 'written into' the South African literary canon whilst promoting recognition of its existence as an oral form. My recent experiences of the difficulties, challenges, and benefits of teaching South African orature within the Rhodes University English department, have alerted me to the urgent need for the creation of a student- and teacher-friendly anthology which would collect, re-voice, and adequately contextualise a selection of the seminal works of South African oral poets from the colonial to the post-apartheid periods. Much of this poetry already exists in print-form but, despite an increasing recognition of oral poetry through a number of endeavours such the Poetry Africa Festival, the Lentswe Poetry Project on SABC 2, the Timbila Poetry Project and others, South African orature remains marginal in the country's literary canon. It is largely absent from the curriculum in the literature departments of its universities. The need to redress this situation is crucial, but the process of setting up and teaching an undergraduate course in South African oral poetry, while possible, is complicated. The works of our most important oral poets are scattered in a variety of books, libraries, and collections. The usual process of drawing up a booklist of set texts is undermined by the stark reality that many of the books are out of print. Fully giving voice to these texts is even harder to achieve - CD and video recordings of performances (if they exist at all) are not easily accessed or disseminated.
- Full Text:
- Date Issued: 2008
Should active recruitment of health workers from sub-Saharan Africa be viewed as a crime?
- Mills, E J, Schabas, W A, Volmink, J, Walker, Roderick B, Ford, N, Katabira, E, Anema, A, Joffres, M, Cahn, P, Montaner, J
- Authors: Mills, E J , Schabas, W A , Volmink, J , Walker, Roderick B , Ford, N , Katabira, E , Anema, A , Joffres, M , Cahn, P , Montaner, J
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6392 , http://hdl.handle.net/10962/d1006314
- Description: (Conclusion) When the international community permits for-profit companies to actively entice overworked and often underpaid workers away from the most vulnerable populations, it is contributing to the deterioration of essential health-care delivery. Improvement of the health of the world’s poor is a challenge that the international community is failing to adequately address. Current international treaties and commitments are severely compromised if we are unwilling to adhere to their principles and prevent obvious harms to poor people. Clear, enforced regulation is needed to prevent recruitment companies from enticing health workers away from their local work, and developed countries should adequately compensate less-developed countries for the human resources they have lost and continue to lose.
- Full Text:
- Date Issued: 2008
- Authors: Mills, E J , Schabas, W A , Volmink, J , Walker, Roderick B , Ford, N , Katabira, E , Anema, A , Joffres, M , Cahn, P , Montaner, J
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6392 , http://hdl.handle.net/10962/d1006314
- Description: (Conclusion) When the international community permits for-profit companies to actively entice overworked and often underpaid workers away from the most vulnerable populations, it is contributing to the deterioration of essential health-care delivery. Improvement of the health of the world’s poor is a challenge that the international community is failing to adequately address. Current international treaties and commitments are severely compromised if we are unwilling to adhere to their principles and prevent obvious harms to poor people. Clear, enforced regulation is needed to prevent recruitment companies from enticing health workers away from their local work, and developed countries should adequately compensate less-developed countries for the human resources they have lost and continue to lose.
- Full Text:
- Date Issued: 2008
Walter Oakley West (1930-2007) : obituary
- Authors: Lewis, Colin A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6703 , http://hdl.handle.net/10962/d1006739
- Full Text:
- Date Issued: 2008
- Authors: Lewis, Colin A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6703 , http://hdl.handle.net/10962/d1006739
- Full Text:
- Date Issued: 2008
Top UN award for leading scientist
- National Research Foundation (NRF)
- Authors: National Research Foundation (NRF)
- Language: English
- Type: Article
- Identifier: vital:7193 , http://hdl.handle.net/10962/d1006357
- Description: Professor Tebello Nyokong holds the DST/NRF funded chair in Medicinal Chemistry and Nanotechnology at Rhodes University
- Full Text:
- Authors: National Research Foundation (NRF)
- Language: English
- Type: Article
- Identifier: vital:7193 , http://hdl.handle.net/10962/d1006357
- Description: Professor Tebello Nyokong holds the DST/NRF funded chair in Medicinal Chemistry and Nanotechnology at Rhodes University
- Full Text:
A broad host range reporter plasmid for the analysis of divergent promoter regions
- Jiwaji, Meesbah, Matcher, Gwynneth F, Dorrington, Rosemary A
- Authors: Jiwaji, Meesbah , Matcher, Gwynneth F , Dorrington, Rosemary A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6476 , http://hdl.handle.net/10962/d1006164 , http://www.scielo.org.za/scielo.php?pid=S0038-23532008000400013&script=sci_arttext
- Description: Although many vectors exist for Escherichia coli and closely related species, there are few broad host range vectors that can be conjugated into a large variety of Gram-negative bacteria. We have constructed a broad host range vector, pMJ445, that facilitates the analysis of divergent promoters in Gram-negative bacteria. The vector was validated using two intergenic regions derived from gene clusters involved in hydantoin hydrolysis, from the environmental isolates Pseudomonas putida and Agrobacterium tumefaciens. The DNA sequences analysed were capable of activating expression of the reporter enzymes, β-glucuronidase and β-galactosidase, present on pMJ445, indicating the presence of divergent promoters in the sequences selected. In addition, we demonstrated that pMJ445 can be applied to gene regulation studies.
- Full Text:
- Date Issued: 2008
- Authors: Jiwaji, Meesbah , Matcher, Gwynneth F , Dorrington, Rosemary A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6476 , http://hdl.handle.net/10962/d1006164 , http://www.scielo.org.za/scielo.php?pid=S0038-23532008000400013&script=sci_arttext
- Description: Although many vectors exist for Escherichia coli and closely related species, there are few broad host range vectors that can be conjugated into a large variety of Gram-negative bacteria. We have constructed a broad host range vector, pMJ445, that facilitates the analysis of divergent promoters in Gram-negative bacteria. The vector was validated using two intergenic regions derived from gene clusters involved in hydantoin hydrolysis, from the environmental isolates Pseudomonas putida and Agrobacterium tumefaciens. The DNA sequences analysed were capable of activating expression of the reporter enzymes, β-glucuronidase and β-galactosidase, present on pMJ445, indicating the presence of divergent promoters in the sequences selected. In addition, we demonstrated that pMJ445 can be applied to gene regulation studies.
- Full Text:
- Date Issued: 2008
A global study of forensically significant calliphorids: implications for identification
- Harvey, M L, Gaudieri, S, Villet, Martin H, Dadour, I R
- Authors: Harvey, M L , Gaudieri, S , Villet, Martin H , Dadour, I R
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6863 , http://hdl.handle.net/10962/d1011156
- Description: A proliferation of molecular studies of the forensically significant Calliphoridae in the last decade has seen molecule-based identification of immature and damaged specimens become a routine complement to traditional morphological identification as a preliminary to the accurate estimation of post-mortem intervals (PMI), which depends on the use of species-specific developmental data. Published molecular studies have tended to focus on generating data for geographically localised communities of species of importance, which has limited the consideration of intraspecific variation in species of global distribution. This study used phylogenetic analysis to assess the species status of 27 forensically important calliphorid species based on 1167 base pairs of the COI gene of 119 specimens from 22 countries, and confirmed the utility of the COI gene in identifying most species. The species Lucilia cuprina, Chrysomya megacephala, Ch. saffranea, Ch. albifrontalis and Calliphora stygia were unable to be monophyletically resolved based on these data. Identification of phylogenetically young species will require a faster-evolving molecular marker, but most species could be unambiguously characterised by sampling relatively few conspecific individuals if they were from distant localities. Intraspecific geographical variation was observed within Ch. rufifacies and L. cuprina, and is discussed with reference to unrecognised species.
- Full Text:
- Date Issued: 2008
- Authors: Harvey, M L , Gaudieri, S , Villet, Martin H , Dadour, I R
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6863 , http://hdl.handle.net/10962/d1011156
- Description: A proliferation of molecular studies of the forensically significant Calliphoridae in the last decade has seen molecule-based identification of immature and damaged specimens become a routine complement to traditional morphological identification as a preliminary to the accurate estimation of post-mortem intervals (PMI), which depends on the use of species-specific developmental data. Published molecular studies have tended to focus on generating data for geographically localised communities of species of importance, which has limited the consideration of intraspecific variation in species of global distribution. This study used phylogenetic analysis to assess the species status of 27 forensically important calliphorid species based on 1167 base pairs of the COI gene of 119 specimens from 22 countries, and confirmed the utility of the COI gene in identifying most species. The species Lucilia cuprina, Chrysomya megacephala, Ch. saffranea, Ch. albifrontalis and Calliphora stygia were unable to be monophyletically resolved based on these data. Identification of phylogenetically young species will require a faster-evolving molecular marker, but most species could be unambiguously characterised by sampling relatively few conspecific individuals if they were from distant localities. Intraspecific geographical variation was observed within Ch. rufifacies and L. cuprina, and is discussed with reference to unrecognised species.
- Full Text:
- Date Issued: 2008
Texts, practices and student learning: a view from the South
- Authors: Boughey, Chrissie
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6085 , http://hdl.handle.net/10962/d1008482
- Description: This article uses ‘close-up’ ethnographic research to provide an account of students’ engagement with learning in a South African university. Broadly based on Halliday’s (1973, 1978, 1994) understanding of texts resulting from contexts, the account challenges dominant constructions of the problems students encounter as stemming from the use of inappropriate ‘approaches’ to learning, the lack of ‘study’ and other skills or problems with proficiency in areas such as writing or language and shows how students’ unfamiliarity with the context of the university leads them to draw on ‘other’ contexts in order to engage with the texts they must read, write and listen to in the course of their studies. This drawing on ‘other’ contexts then results in the texts produced by students, and the practices which give rise to those texts, being inappropriate to the context of the university. Although the research on which the article is based took place in South Africa, it is argued that the theoretical perspective it provides has relevance across other contexts given the increasingly diverse student bodies which characterize higher education across the globe.
- Full Text:
- Date Issued: 2008
- Authors: Boughey, Chrissie
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6085 , http://hdl.handle.net/10962/d1008482
- Description: This article uses ‘close-up’ ethnographic research to provide an account of students’ engagement with learning in a South African university. Broadly based on Halliday’s (1973, 1978, 1994) understanding of texts resulting from contexts, the account challenges dominant constructions of the problems students encounter as stemming from the use of inappropriate ‘approaches’ to learning, the lack of ‘study’ and other skills or problems with proficiency in areas such as writing or language and shows how students’ unfamiliarity with the context of the university leads them to draw on ‘other’ contexts in order to engage with the texts they must read, write and listen to in the course of their studies. This drawing on ‘other’ contexts then results in the texts produced by students, and the practices which give rise to those texts, being inappropriate to the context of the university. Although the research on which the article is based took place in South Africa, it is argued that the theoretical perspective it provides has relevance across other contexts given the increasingly diverse student bodies which characterize higher education across the globe.
- Full Text:
- Date Issued: 2008
Photophysicochemical and fFluorescence quenching studies of benzyloxyphenoxy substituted zinc phthalocyanines
- Authors: Durmuş, M , Nyokong, Tebello
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6570 , http://hdl.handle.net/10962/d1004133
- Description: Photochemical and photophysical measurements were conducted on peripheral and non-peripheral tetrakis- and octakis(4-benzyloxyphenoxy)-substituted zinc phthalocyanines (1, 2 and 3). General trends are described for photodegradation, and fluorescence quantum yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds in dimethylsulphoxide (DMSO) and toluene. The fluorescence of the complexes is quenched by benzoquinone (BQ), and fluorescence quenching properties are investigated in DMSO and toluene. The effects of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (1, 2 and 3) are also reported. Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications.
- Full Text:
- Date Issued: 2008
- Authors: Durmuş, M , Nyokong, Tebello
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6570 , http://hdl.handle.net/10962/d1004133
- Description: Photochemical and photophysical measurements were conducted on peripheral and non-peripheral tetrakis- and octakis(4-benzyloxyphenoxy)-substituted zinc phthalocyanines (1, 2 and 3). General trends are described for photodegradation, and fluorescence quantum yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds in dimethylsulphoxide (DMSO) and toluene. The fluorescence of the complexes is quenched by benzoquinone (BQ), and fluorescence quenching properties are investigated in DMSO and toluene. The effects of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (1, 2 and 3) are also reported. Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications.
- Full Text:
- Date Issued: 2008
A phenomenological case study of a lecturer's understanding of himself as an assessor
- Authors: Grant, Rose
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6087 , http://hdl.handle.net/10962/d1008582
- Description: Based on the findings of research conducted as part of a doctoral study aimed at obtaining an understanding of what it means to be an assessor in higher education, this paper outlines the experience of an individual lecturer at a South African university and describes the meaning he makes of his practice as an assessor within the context of a changing understanding of the nature and purpose of higher education. Making a case for personal agency and innovation as critical qualities in the assessment endeavour, the researcher suggests that, in contrast to a view of education increasingly focused on standardization, accountability and outcomes, student assessment is essentially a human encounter in which the humanity and emotions of both lecturer and student need to be acknowledged.
- Full Text:
- Date Issued: 2008
- Authors: Grant, Rose
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6087 , http://hdl.handle.net/10962/d1008582
- Description: Based on the findings of research conducted as part of a doctoral study aimed at obtaining an understanding of what it means to be an assessor in higher education, this paper outlines the experience of an individual lecturer at a South African university and describes the meaning he makes of his practice as an assessor within the context of a changing understanding of the nature and purpose of higher education. Making a case for personal agency and innovation as critical qualities in the assessment endeavour, the researcher suggests that, in contrast to a view of education increasingly focused on standardization, accountability and outcomes, student assessment is essentially a human encounter in which the humanity and emotions of both lecturer and student need to be acknowledged.
- Full Text:
- Date Issued: 2008
Industrial relations in Namibia since independence: between neo-liberalism and neo-corporatism?
- Authors: Klerck, Gilton
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6320 , http://hdl.handle.net/10962/d1011314
- Description: The paper seeks to examine the changes and continuities in industrial relations in post-independence Namibia. In particular, it aims to explore some of the key elements in the process through which the distribution of the costs and rewards of economic and industrial restructuring is institutionalised. The paper concentrates, through in-depth interviews with key role players, on how the attempts at sustaining a durable and redistributive trade-off between economic efficiency and social equality led to a contradictory fusion of neo-liberal and neo-corporatist forms of labour market regulation. The research reveals that changes in the regulation of the labour market since independence have created opportunities for advancement and participation by groups of more skilled and organised employees, while weaker and less skilled groups have generally experienced a decline in employment conditions and the absence of collective representation. These developments reflect and reproduce patterns of racial and gender discrimination, industrial structure, trade union membership and collective bargaining across the various sectors and occupations. The paper shows that a system of low-skill, low-wage and low-trust relations - with an emphasis on cost reduction and employment "flexibility" - is fast becoming embedded in industrial relations in Namibia. Given the prevailing economic policies, industrial strategies and labour market structures, Namibia's integration into the global economy will most likely involve the increasing dislocation and exclusion of vulnerable and "peripheral" workers from the formal economy. The paper highlights the ways in which the transformation of industrial relations in Namibia is shaped by the legacy of apartheid-colonialism and the pressures of globalisation. Specifically, the conjunction of increasingly deregulated product markets and increasingly regulated labour markets has driven a wedge between the pursuit of short-term objectives and the attainment of long-term transformational goals.
- Full Text:
- Date Issued: 2008
- Authors: Klerck, Gilton
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6320 , http://hdl.handle.net/10962/d1011314
- Description: The paper seeks to examine the changes and continuities in industrial relations in post-independence Namibia. In particular, it aims to explore some of the key elements in the process through which the distribution of the costs and rewards of economic and industrial restructuring is institutionalised. The paper concentrates, through in-depth interviews with key role players, on how the attempts at sustaining a durable and redistributive trade-off between economic efficiency and social equality led to a contradictory fusion of neo-liberal and neo-corporatist forms of labour market regulation. The research reveals that changes in the regulation of the labour market since independence have created opportunities for advancement and participation by groups of more skilled and organised employees, while weaker and less skilled groups have generally experienced a decline in employment conditions and the absence of collective representation. These developments reflect and reproduce patterns of racial and gender discrimination, industrial structure, trade union membership and collective bargaining across the various sectors and occupations. The paper shows that a system of low-skill, low-wage and low-trust relations - with an emphasis on cost reduction and employment "flexibility" - is fast becoming embedded in industrial relations in Namibia. Given the prevailing economic policies, industrial strategies and labour market structures, Namibia's integration into the global economy will most likely involve the increasing dislocation and exclusion of vulnerable and "peripheral" workers from the formal economy. The paper highlights the ways in which the transformation of industrial relations in Namibia is shaped by the legacy of apartheid-colonialism and the pressures of globalisation. Specifically, the conjunction of increasingly deregulated product markets and increasingly regulated labour markets has driven a wedge between the pursuit of short-term objectives and the attainment of long-term transformational goals.
- Full Text:
- Date Issued: 2008
Hydrolytic enzymes in sewage sludge treatment: a mini-review
- Burgess, Jo E, Pletschke, Brett I
- Authors: Burgess, Jo E , Pletschke, Brett I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6478 , http://hdl.handle.net/10962/d1006166 , http://hdl.handle.net/10520/EJC116535
- Description: Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
- Full Text:
- Date Issued: 2008
- Authors: Burgess, Jo E , Pletschke, Brett I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6478 , http://hdl.handle.net/10962/d1006166 , http://hdl.handle.net/10520/EJC116535
- Description: Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
- Full Text:
- Date Issued: 2008
Deriving narrow syntax through constraints on information structure : a parallel between linguistic models of displacement and database theory
- Authors: de Vos, Mark
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6142 , http://hdl.handle.net/10962/d1011594
- Description: This paper presents a research program for normalization-driven syntax. It takes the Minimalist research agenda as a starting point (Chomsky 1995. The Minimalist Program. MIT Press, Cambridge MA.) and explores the question of how the CI interface determines syntactic operations. The proposal provides specific content to the notion of bare output conditions and the nature of the CI interface. It does so by drawing on the tools provided by Relational Theory, a branch of set-theoretic mathematics, and Database Theory, a branch of computer science. It is demonstrated that core components of Narrow Syntax (phrase structure, selection and AGREE) are all definable in terms of Relational Theory. Then, it is shown that the process of relation optimization, or normalization, can derive chain formation. The article concludes with two speculations on the implementation of phases within a normalization-driven grammar and the implications of such a system for the learnability of the lexicon.
- Full Text:
- Date Issued: 2008
- Authors: de Vos, Mark
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6142 , http://hdl.handle.net/10962/d1011594
- Description: This paper presents a research program for normalization-driven syntax. It takes the Minimalist research agenda as a starting point (Chomsky 1995. The Minimalist Program. MIT Press, Cambridge MA.) and explores the question of how the CI interface determines syntactic operations. The proposal provides specific content to the notion of bare output conditions and the nature of the CI interface. It does so by drawing on the tools provided by Relational Theory, a branch of set-theoretic mathematics, and Database Theory, a branch of computer science. It is demonstrated that core components of Narrow Syntax (phrase structure, selection and AGREE) are all definable in terms of Relational Theory. Then, it is shown that the process of relation optimization, or normalization, can derive chain formation. The article concludes with two speculations on the implementation of phases within a normalization-driven grammar and the implications of such a system for the learnability of the lexicon.
- Full Text:
- Date Issued: 2008
Establishing a basis for ecosystem management in the western Indian Ocean
- Vousden, David, Scott, Lucy E P, Sauer, Warwick H H, Bornman, T G, Ngoile, M, Stapley, J, Lutjeharms, Johan R E
- Authors: Vousden, David , Scott, Lucy E P , Sauer, Warwick H H , Bornman, T G , Ngoile, M , Stapley, J , Lutjeharms, Johan R E
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6774 , http://hdl.handle.net/10962/d1008081
- Description: An ambitious multinational programme, with generous funding for an initial five years, aims to provide understanding of marine resources for the benefit of impoverished island and coastal populations in a much-neglected ocean region.
- Full Text:
- Date Issued: 2008
- Authors: Vousden, David , Scott, Lucy E P , Sauer, Warwick H H , Bornman, T G , Ngoile, M , Stapley, J , Lutjeharms, Johan R E
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6774 , http://hdl.handle.net/10962/d1008081
- Description: An ambitious multinational programme, with generous funding for an initial five years, aims to provide understanding of marine resources for the benefit of impoverished island and coastal populations in a much-neglected ocean region.
- Full Text:
- Date Issued: 2008
The effects of load and gradient on hand force responses during dynamic pushing and pulling tasks
- Bennett, Anthea I, Desai, Sheena D, Todd, Andrew I, Freeland, H
- Authors: Bennett, Anthea I , Desai, Sheena D , Todd, Andrew I , Freeland, H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6757 , http://hdl.handle.net/10962/d1009459
- Description: The limited attention afforded to push/pull activities and the motion phases (initial, sustained and ending) characteristic of these tasks has prompted a research focus in this area. The present study examined biomechanical responses in the form of hand forces during dynamic submaximal trolley pushing and pulling. Participants pushed/pulled loads of 100, 200 and 300 kg on the level (determining impact of load) or pushed 100 kg along a 12° ramp (uphill and downhill- determining impact of gradient). During level exertions significant differences (p<0.05) in hand forces occurred between loads of 100 and 200 kg, and 100 and 300 kg for initial and sustained forces but not ending forces. Values were similar for pushing and pulling at respective loads and motion phases. Strong correlations indicate that initial forces can be used to accurately estimate sustained and ending forces. Importantly, correct technique is essential in force reduction. Forces were highest during uphill initial and sustained phases and the downhill sustained phase. For the initial phase, the forces were highest during uphill pushing (86.5 ± 25.73 N); for the sustained phase, there was no difference between uphill and downhill forces but level forces were significantly lower (18.19 ± 8.09 N) than either of the other two conditions; for the ending phase, the highest forces were produced during downhill pushing (-53.34 ± 13.65N). As sustained forces equaled or exceeded initial forces for uphill and downhill efforts, consideration of sustained forces may be appropriate in determining the inherent potential risk of graded pushing.
- Full Text:
- Date Issued: 2008
- Authors: Bennett, Anthea I , Desai, Sheena D , Todd, Andrew I , Freeland, H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6757 , http://hdl.handle.net/10962/d1009459
- Description: The limited attention afforded to push/pull activities and the motion phases (initial, sustained and ending) characteristic of these tasks has prompted a research focus in this area. The present study examined biomechanical responses in the form of hand forces during dynamic submaximal trolley pushing and pulling. Participants pushed/pulled loads of 100, 200 and 300 kg on the level (determining impact of load) or pushed 100 kg along a 12° ramp (uphill and downhill- determining impact of gradient). During level exertions significant differences (p<0.05) in hand forces occurred between loads of 100 and 200 kg, and 100 and 300 kg for initial and sustained forces but not ending forces. Values were similar for pushing and pulling at respective loads and motion phases. Strong correlations indicate that initial forces can be used to accurately estimate sustained and ending forces. Importantly, correct technique is essential in force reduction. Forces were highest during uphill initial and sustained phases and the downhill sustained phase. For the initial phase, the forces were highest during uphill pushing (86.5 ± 25.73 N); for the sustained phase, there was no difference between uphill and downhill forces but level forces were significantly lower (18.19 ± 8.09 N) than either of the other two conditions; for the ending phase, the highest forces were produced during downhill pushing (-53.34 ± 13.65N). As sustained forces equaled or exceeded initial forces for uphill and downhill efforts, consideration of sustained forces may be appropriate in determining the inherent potential risk of graded pushing.
- Full Text:
- Date Issued: 2008
A preliminary investigation of spinal kinematics during sugar cane harvesting
- Authors: Todd, Andrew I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6759 , http://hdl.handle.net/10962/d1009462
- Description: The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry.
- Full Text:
- Date Issued: 2008
- Authors: Todd, Andrew I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6759 , http://hdl.handle.net/10962/d1009462
- Description: The sugar cane industry forms a significant portion of the South African economy, and unlike many other countries the harvesting of sugar cane in South Africa remains manual in nature. The focus of the present study was therefore on the assessment of spinal kinematics (range of motion, velocities and accelerations in all three cardinal planes) during the harvesting process. Eight workers were recruited from the Illovo Esperanza farm in Kwa-zulu Natal as subjects for the study. The experimental protocol was conducted in situ and required subjects to cut the sugar cane using specially modified knives as they would under normal harvesting conditions. The motion performance was quantified using the lumbar motion monitor (LMM), a triaxial electrogoniometer. Results indicate that the harvesting of sugar cane places excessive demands on the spine. During cutting, subjects were required to maintain the spine in a high degree of flexion throughout the task which also demonstrated significant twisting and lateral bending. Of particular concern were the high lateral velocities (ranging between 50 and 90 m.s-1), as this is a key risk factor in the development of lower back pain. It is evident from these results that new techniques of harvesting sugar cane are essential to reduce the rate of injury within this industry.
- Full Text:
- Date Issued: 2008
Optimisation of Bacillus thuringiensis var. israelensis (Vectobac®) applications for the blackfly control programme on the Orange River, South Africa
- Rivers-Moore, N A, Bangay, Shaun D, Palmer, R W
- Authors: Rivers-Moore, N A , Bangay, Shaun D , Palmer, R W
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:7090 , http://hdl.handle.net/10962/d1012421
- Description: The Orange River, South Africa's largest river, is a critical water resource for the country. In spite of the clear economic benefits of regulating river flows through a series of impoundments, one of the significant undesirable ecological consequences of this regulation has been the regular outbreaks of the pest blackfly species Simulium chutteri and S. damnosum s.l. (Diptera: Simuliidae). The current control programme, carried out by the South African National Department of Agriculture, uses regular applications, by helicopter, of the target-specific bacterial larvicide Bacillus thuringiensis var. israelensis. While cost-benefit analyses show significant benefits to the control programme, benefits could potentially be further increased through applying smaller volumes of larvicide in an optimised manner, which incorporates upstream residual amounts of pesticide through downstream carry. Using an optimisation technique applied in the West African Onchocerciasis Control Programme, to a 136 km stretch of the Orange River which includes 31 blackfly breeding sites, we demonstrate that 28.5% less larvicide could be used to potentially achieve the same control of blackfly. This translates into potential annual savings of between R540 000 and R1 800 000. A comparison of larvicide volumes estimated using traditional vs. optimised approaches at different discharges, illustrates that the savings on optimisation decline linearly with increasing flow volumes. Larvicide applications at the lowest discharge considered (40 m3·s-1) showed the greatest benefits from optimisations, with benefits remaining but decreasing to a theoretical 30% up to median flows of 100 m3·s-1. Given that almost 70% of flows in July are less than 100 m3·s-1, we suggest that an optimised approach is appropriate for the Orange River Blackfly Control Programme, particularly for flow volumes of less than 100 m3·s-1. We recommend that trials be undertaken over two reaches of the Orange River, one using the traditional approach, and another using the optimised approach, to test the efficacy of using optimised volumes of B.t.i.
- Full Text:
- Date Issued: 2008
- Authors: Rivers-Moore, N A , Bangay, Shaun D , Palmer, R W
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:7090 , http://hdl.handle.net/10962/d1012421
- Description: The Orange River, South Africa's largest river, is a critical water resource for the country. In spite of the clear economic benefits of regulating river flows through a series of impoundments, one of the significant undesirable ecological consequences of this regulation has been the regular outbreaks of the pest blackfly species Simulium chutteri and S. damnosum s.l. (Diptera: Simuliidae). The current control programme, carried out by the South African National Department of Agriculture, uses regular applications, by helicopter, of the target-specific bacterial larvicide Bacillus thuringiensis var. israelensis. While cost-benefit analyses show significant benefits to the control programme, benefits could potentially be further increased through applying smaller volumes of larvicide in an optimised manner, which incorporates upstream residual amounts of pesticide through downstream carry. Using an optimisation technique applied in the West African Onchocerciasis Control Programme, to a 136 km stretch of the Orange River which includes 31 blackfly breeding sites, we demonstrate that 28.5% less larvicide could be used to potentially achieve the same control of blackfly. This translates into potential annual savings of between R540 000 and R1 800 000. A comparison of larvicide volumes estimated using traditional vs. optimised approaches at different discharges, illustrates that the savings on optimisation decline linearly with increasing flow volumes. Larvicide applications at the lowest discharge considered (40 m3·s-1) showed the greatest benefits from optimisations, with benefits remaining but decreasing to a theoretical 30% up to median flows of 100 m3·s-1. Given that almost 70% of flows in July are less than 100 m3·s-1, we suggest that an optimised approach is appropriate for the Orange River Blackfly Control Programme, particularly for flow volumes of less than 100 m3·s-1. We recommend that trials be undertaken over two reaches of the Orange River, one using the traditional approach, and another using the optimised approach, to test the efficacy of using optimised volumes of B.t.i.
- Full Text:
- Date Issued: 2008
Biological responses to a resumption in river flow in a freshwater-deprived, permanently open Southern African estuary
- Vorwerk, Paul D, Froneman, P William, Paterson, Angus W, Strydom, Nadine A, Whitfield, A K
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, A K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, A K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
Oxbridge clerics and early ringing in South Africa
- Authors: Lewis, Colin A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6186 , http://hdl.handle.net/10962/d1012384
- Description: During the early Twentieth Century, many gifted British clergy came to South Africa. They must have felt optimistic that many rings of bells would soon be installed in their adopted country. South Africa had survived the Boer Wars, the economy was reasonably healthy, new churches were being built and many others were being planned. The Union of South Africa was only a few years old and the political stability of this great part of the British Empire seemed assured. Sadly, their optimism was misplaced and in 2008 only eight rings exist in South Africa. Had it not been for the efforts of the Oxbridge trio: J.R. Vincent, G.H. Ridout and C.E.E. Bulwer, and other British immigrants, however, these rings would not exist. , 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: 2008
- Authors: Lewis, Colin A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6186 , http://hdl.handle.net/10962/d1012384
- Description: During the early Twentieth Century, many gifted British clergy came to South Africa. They must have felt optimistic that many rings of bells would soon be installed in their adopted country. South Africa had survived the Boer Wars, the economy was reasonably healthy, new churches were being built and many others were being planned. The Union of South Africa was only a few years old and the political stability of this great part of the British Empire seemed assured. Sadly, their optimism was misplaced and in 2008 only eight rings exist in South Africa. Had it not been for the efforts of the Oxbridge trio: J.R. Vincent, G.H. Ridout and C.E.E. Bulwer, and other British immigrants, however, these rings would not exist. , 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: 2008