A novel biosensor for the detection and monitoring of -d-galactosidase of faecal origin in water
- Wutor, V C, Togo, C A, Limson, Janice L, Pletschke, Brett I
- Authors: Wutor, V C , Togo, C A , Limson, Janice L , Pletschke, Brett I
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6468 , http://hdl.handle.net/10962/d1005797 , http://dx.doi.org/10.1016/j.enzmictec.2006.10.039
- Description: A voltammetric sensor prepared by the immobilization of metallophthalocyanine complexes onto a glassy carbon electrode has been developed for the detection of β-d-galactosidase (B-GAL) of faecal origin in water. Electrooxidation of chlorophenol red, a breakdown product of the chromogenic substrate chlorophenol red β-d-galactopyranoside, was used as a measure of β-d-galactosidase activity. At metallophthalocyanine modified electrodes, in particular copper(II) phthalocyanine, a decrease in electrode fouling was observed. The sensor was sensitive to fluctuations in pH, not significantly affected by temperature variations and could detect one colony forming unit/100 mL in 15 min. Loss of 40% sensitivity was observed over a period of 30 days. A strong correlation between sensor sensitivity and colony forming units was observed. The sensor is capable of detecting viable but nonculturable bacteria, overcoming this drawback of the use of culture media for detection of coliforms.
- Full Text:
- Date Issued: 2007
- Authors: Wutor, V C , Togo, C A , Limson, Janice L , Pletschke, Brett I
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6468 , http://hdl.handle.net/10962/d1005797 , http://dx.doi.org/10.1016/j.enzmictec.2006.10.039
- Description: A voltammetric sensor prepared by the immobilization of metallophthalocyanine complexes onto a glassy carbon electrode has been developed for the detection of β-d-galactosidase (B-GAL) of faecal origin in water. Electrooxidation of chlorophenol red, a breakdown product of the chromogenic substrate chlorophenol red β-d-galactopyranoside, was used as a measure of β-d-galactosidase activity. At metallophthalocyanine modified electrodes, in particular copper(II) phthalocyanine, a decrease in electrode fouling was observed. The sensor was sensitive to fluctuations in pH, not significantly affected by temperature variations and could detect one colony forming unit/100 mL in 15 min. Loss of 40% sensitivity was observed over a period of 30 days. A strong correlation between sensor sensitivity and colony forming units was observed. The sensor is capable of detecting viable but nonculturable bacteria, overcoming this drawback of the use of culture media for detection of coliforms.
- Full Text:
- Date Issued: 2007
Growth of Aloe ferox Mill. at selected sites in the Makana region of the Eastern Cape
- Shackleton, Charlie M, Gambiza, James
- Authors: Shackleton, Charlie M , Gambiza, James
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6654 , http://hdl.handle.net/10962/d1007068
- Description: There is widespread harvesting of the leaves of Aloe ferox to supply bitters and gel for cosmetic and health products. Government and private agencies are interested in expanding the industry as a means of providing income for poor rural communities. With the growing interest in the commercial use of A. ferox it is important that harvesting programmes are based on an adequate understanding of the ecology and productivity of the species, which will underpin estimates of possible sustainable yields. In this paper we report mean annual growth rates of 283 A. ferox plants (at six sites) during the 2005/2006 season. Growth was variable across sites and plant height. In terms of sites, the mean height growth ranged between 1.7 cm per plant per year at site 4 and 4.6 cm at site 2. The mean height increment across all sites and plants was 2.8 ± 0.2 cm. Plant height had a strong effect on annual increment with small plants (< 6 cm) more than doubling their height in the 12 month period, whereas plants taller than 2 m grew by approximately 1% over the year. Across the five unburnt sites, the mean standing stock of leaves grew by two per plant. The proportion of plants flowering increased progressively with plant height. Most (90%) of the plants that flowered in 2005 did so again in 2006.
- Full Text:
- Date Issued: 2007
- Authors: Shackleton, Charlie M , Gambiza, James
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6654 , http://hdl.handle.net/10962/d1007068
- Description: There is widespread harvesting of the leaves of Aloe ferox to supply bitters and gel for cosmetic and health products. Government and private agencies are interested in expanding the industry as a means of providing income for poor rural communities. With the growing interest in the commercial use of A. ferox it is important that harvesting programmes are based on an adequate understanding of the ecology and productivity of the species, which will underpin estimates of possible sustainable yields. In this paper we report mean annual growth rates of 283 A. ferox plants (at six sites) during the 2005/2006 season. Growth was variable across sites and plant height. In terms of sites, the mean height growth ranged between 1.7 cm per plant per year at site 4 and 4.6 cm at site 2. The mean height increment across all sites and plants was 2.8 ± 0.2 cm. Plant height had a strong effect on annual increment with small plants (< 6 cm) more than doubling their height in the 12 month period, whereas plants taller than 2 m grew by approximately 1% over the year. Across the five unburnt sites, the mean standing stock of leaves grew by two per plant. The proportion of plants flowering increased progressively with plant height. Most (90%) of the plants that flowered in 2005 did so again in 2006.
- Full Text:
- Date Issued: 2007
Making visible constructions of dis/advantage through genealogical investigation: South African schooled literacies
- Authors: Prinsloo, Jeanne
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147869 , vital:38680 , DOI: 10.1080/02560040701398889
- Description: In this paper I assume the relevance of Foucauldian insights for conducting socio-cultural critique and I argue the significance of genealogical work in relation to understanding the present. Thus, I seek both to establish what could constitute a genealogical investigation and to illustrate this by describing and discussing a study, undertaken within a genealogical frame, into literacy practices within a specifically South African context. I investigated the differing schooled literacies in KwaZulu-Natal province in South Africa over three decades along the language lines of Afrikaans, English and Zulu. The findings propose that the differing sets of literacy practices validate different subjects – and that they are implicated in constructing dis/advantage.
- Full Text:
- Date Issued: 2007
- Authors: Prinsloo, Jeanne
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147869 , vital:38680 , DOI: 10.1080/02560040701398889
- Description: In this paper I assume the relevance of Foucauldian insights for conducting socio-cultural critique and I argue the significance of genealogical work in relation to understanding the present. Thus, I seek both to establish what could constitute a genealogical investigation and to illustrate this by describing and discussing a study, undertaken within a genealogical frame, into literacy practices within a specifically South African context. I investigated the differing schooled literacies in KwaZulu-Natal province in South Africa over three decades along the language lines of Afrikaans, English and Zulu. The findings propose that the differing sets of literacy practices validate different subjects – and that they are implicated in constructing dis/advantage.
- Full Text:
- Date Issued: 2007
Neural network-based prediction techniques for global modeling of M(3000)F2 ionospheric parameter
- Oyeyemi, E O, McKinnell, Lee-Anne, Poole, Allon W V
- Authors: Oyeyemi, E O , McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6803 , http://hdl.handle.net/10962/d1004166
- Description: In recent times neural networks (NNs) have been employed to solve many problems in ionospheric predictions. This paper illustrates a new application of NNs in developing a global model of the ionospheric propagation factor M(3000)F2. NNs were trained with daily hourly values of M(3000)F2 from various ionospheric stations spanning the period 1964–1986 with the following temporal and spatial input parameters: Universal Time, geographic latitude, magnetic inclination, magnetic declination, solar zenith angle, day of the year, A16 index (a 2-day running mean of the 3-h planetary magnetic ap index), R2 index (a 2-month running mean of sunspot number), and the angle of meridian relative to the subsolar point. The performance of the NNs was verified by comparing the predicted values of M(3000)F2 with observed values from a few selected ionospheric stations and the IRI (International Reference Ionosphere) model (CCIR M(3000)F2 model) predicted values. The results obtained compared favourably with the IRI model. Based on the error differences, the result obtained justifies the potential of the NN technique for the predictions of M(3000)F2 values on a global scale.
- Full Text:
- Date Issued: 2007
- Authors: Oyeyemi, E O , McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6803 , http://hdl.handle.net/10962/d1004166
- Description: In recent times neural networks (NNs) have been employed to solve many problems in ionospheric predictions. This paper illustrates a new application of NNs in developing a global model of the ionospheric propagation factor M(3000)F2. NNs were trained with daily hourly values of M(3000)F2 from various ionospheric stations spanning the period 1964–1986 with the following temporal and spatial input parameters: Universal Time, geographic latitude, magnetic inclination, magnetic declination, solar zenith angle, day of the year, A16 index (a 2-day running mean of the 3-h planetary magnetic ap index), R2 index (a 2-month running mean of sunspot number), and the angle of meridian relative to the subsolar point. The performance of the NNs was verified by comparing the predicted values of M(3000)F2 with observed values from a few selected ionospheric stations and the IRI (International Reference Ionosphere) model (CCIR M(3000)F2 model) predicted values. The results obtained compared favourably with the IRI model. Based on the error differences, the result obtained justifies the potential of the NN technique for the predictions of M(3000)F2 values on a global scale.
- Full Text:
- Date Issued: 2007
Role playing African development : an international comparison
- Fox, Roddy C, Assmo, P, Kjellgren, H
- Authors: Fox, Roddy C , Assmo, P , Kjellgren, H
- Date: 2007
- Language: English
- Type: Conference paper
- Identifier: vital:6665 , http://hdl.handle.net/10962/d1006676
- Description: The African Development Game is a role playing simulation developed to demonstrate the difficulties six African countries face in reaching the Millennium Development Goals. The game has been played in three different countries, South Africa, Sweden and Finland, to examine its utility as a learning tool for students who are unfamiliar both with the Millennium Development Goals and the problems of African development. Analysis of the games played in South Africa and Sweden. is based on a comparison of student reflections supplemented by participant observation and spreadsheet information of economic performances. Marked differences in the types of learning and success in repaying debt were observed between the two groups of students. They all commented, however, on the effectiveness of the role play as a learning tool.
- Full Text:
- Date Issued: 2007
- Authors: Fox, Roddy C , Assmo, P , Kjellgren, H
- Date: 2007
- Language: English
- Type: Conference paper
- Identifier: vital:6665 , http://hdl.handle.net/10962/d1006676
- Description: The African Development Game is a role playing simulation developed to demonstrate the difficulties six African countries face in reaching the Millennium Development Goals. The game has been played in three different countries, South Africa, Sweden and Finland, to examine its utility as a learning tool for students who are unfamiliar both with the Millennium Development Goals and the problems of African development. Analysis of the games played in South Africa and Sweden. is based on a comparison of student reflections supplemented by participant observation and spreadsheet information of economic performances. Marked differences in the types of learning and success in repaying debt were observed between the two groups of students. They all commented, however, on the effectiveness of the role play as a learning tool.
- Full Text:
- Date Issued: 2007
South African marxist state theory: a critical overview
- Authors: Helliker, Kirk D
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144778 , vital:38378 , DOI: 10.1080/02589348808704885
- Description: The article provides a critical analysis of Marxist work on the South African state. It first examines the early Poulantzian‐State Derivationist debate on the relation between state and society, and then discusses the ‘new directions’ which focus on the state itself. The sensitivity of the ‘new directions’ to the traditional Weberian concern about state bureaucracy is important for enriching Marxist theory. But the article concludes by suggesting that a comprehensive dialectical Marxist approach to the South African state still awaits development.
- Full Text:
- Date Issued: 2007
- Authors: Helliker, Kirk D
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144778 , vital:38378 , DOI: 10.1080/02589348808704885
- Description: The article provides a critical analysis of Marxist work on the South African state. It first examines the early Poulantzian‐State Derivationist debate on the relation between state and society, and then discusses the ‘new directions’ which focus on the state itself. The sensitivity of the ‘new directions’ to the traditional Weberian concern about state bureaucracy is important for enriching Marxist theory. But the article concludes by suggesting that a comprehensive dialectical Marxist approach to the South African state still awaits development.
- Full Text:
- Date Issued: 2007
Written medicines information for South African HIV/AIDS patients: does it enhance understanding of co-trimoxazole therapy?
- Mansoor, Leila E, Dowse, Roslind
- Authors: Mansoor, Leila E , Dowse, Roslind
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156860 , vital:40059 , https://0-doi.org.wam.seals.ac.za/10.1093/her/cyl039
- Description: Written information to promote patient education is being increasingly recognized as an integral part of quality health care. The main objective of this study was to evaluate the effect of distributing a patient information leaflet (PIL) on knowledge acquisition and recall. Two different PILs were designed for co-trimoxazole tablets: a simple, shorter PIL that incorporated pictograms and text and a text-only PIL that was longer and more complex. Human immunodeficiency virus-positive participants on chronic co-trimoxazole therapy were enrolled from five local primary health care clinics in Grahamstown, South Africa, and were randomly allocated to a Control Group (no PIL), Group A (text-only PIL) or Group B (simple PIL with pictograms).
- Full Text:
- Date Issued: 2007
- Authors: Mansoor, Leila E , Dowse, Roslind
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156860 , vital:40059 , https://0-doi.org.wam.seals.ac.za/10.1093/her/cyl039
- Description: Written information to promote patient education is being increasingly recognized as an integral part of quality health care. The main objective of this study was to evaluate the effect of distributing a patient information leaflet (PIL) on knowledge acquisition and recall. Two different PILs were designed for co-trimoxazole tablets: a simple, shorter PIL that incorporated pictograms and text and a text-only PIL that was longer and more complex. Human immunodeficiency virus-positive participants on chronic co-trimoxazole therapy were enrolled from five local primary health care clinics in Grahamstown, South Africa, and were randomly allocated to a Control Group (no PIL), Group A (text-only PIL) or Group B (simple PIL with pictograms).
- Full Text:
- Date Issued: 2007
Population structure and growth of polydorid polychaetes that infest cultured abalone Haliotis midae
- Simon, Carol A, Booth, Anthony J
- Authors: Simon, Carol A , Booth, Anthony J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125731 , vital:35812 , https://doi.10.2989/AJMS.2007.29.3.16.346
- Description: Polydorid polychaetes can infest cultured abalone thereby reducing productivity. In order to effectively control these pests, their reproductive biology must be understood. The population dynamics and reproduction of polydorids infesting abalone Haliotis midae from two farms in South Africa is described using a length-based, age-structured model. Shells were infested mainly by introduced Boccardia proboscidea. Polydora hoplura and Dipolydora capensis were also present but in numbers too few to identify factors influencing infestation. At both farms, B. proboscidea lived for a minimum of 12 months. Growth rate, size at maturity, maximum size, infestation intensity, recruitment, percentage of the population brooding and mortality appear to be affected by abalone feeding regime and water temperature, and these factors need to be considered in controlling infestation. Brooders and recruits were present throughout the year, but increased significantly during mid- to late winter/early spring when water temperature and day length increased. Treatment measures should therefore be implemented throughout the year but with increased effort when water temperature increases.
- Full Text:
- Date Issued: 2010
Population structure and growth of polydorid polychaetes that infest cultured abalone Haliotis midae
- Authors: Simon, Carol A , Booth, Anthony J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125731 , vital:35812 , https://doi.10.2989/AJMS.2007.29.3.16.346
- Description: Polydorid polychaetes can infest cultured abalone thereby reducing productivity. In order to effectively control these pests, their reproductive biology must be understood. The population dynamics and reproduction of polydorids infesting abalone Haliotis midae from two farms in South Africa is described using a length-based, age-structured model. Shells were infested mainly by introduced Boccardia proboscidea. Polydora hoplura and Dipolydora capensis were also present but in numbers too few to identify factors influencing infestation. At both farms, B. proboscidea lived for a minimum of 12 months. Growth rate, size at maturity, maximum size, infestation intensity, recruitment, percentage of the population brooding and mortality appear to be affected by abalone feeding regime and water temperature, and these factors need to be considered in controlling infestation. Brooders and recruits were present throughout the year, but increased significantly during mid- to late winter/early spring when water temperature and day length increased. Treatment measures should therefore be implemented throughout the year but with increased effort when water temperature increases.
- Full Text:
- Date Issued: 2010
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