Demand-side management of internet bandwidth
- Authors: Halse, Guy A
- Date: 2008
- Language: English
- Type: Conference paper
- Identifier: vital:6607 , http://hdl.handle.net/10962/d1009463
- Description: Presentation on the demand-side management of Internet bandwidth, using Rhodes University as a case study, as presented at the DITCHE national techie event in September 2008.
- Full Text:
- Authors: Halse, Guy A
- Date: 2008
- Language: English
- Type: Conference paper
- Identifier: vital:6607 , http://hdl.handle.net/10962/d1009463
- Description: Presentation on the demand-side management of Internet bandwidth, using Rhodes University as a case study, as presented at the DITCHE national techie event in September 2008.
- Full Text:
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:
- 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:
Designing a framework for animal identification
- Krijer, Hans, Foster, Greg, Bangay, Shaun D
- Authors: Krijer, Hans , Foster, Greg , Bangay, Shaun D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432726 , vital:72895 , https://www.cs.ru.ac.za/research/g99k3906/hans.pdf
- Description: The conventional methods of animal identification can be replaced with a semi-automatic image analysis tool, which distinguishes individuals based on their unique markings. A flexible framework for the analysis must encompass a combination of relevant features with interchangeable animal-specific modules. Developing a Java-ImageJ plug-in alleviates routine functionality, but enforces some degree of conformity. Zebra photographs are used as the initial data under consideration. De-interlacing, adaptive thresholding, smoothing and sharpening are identified as beneficial pre-processing steps. Binarisation and sequential thinning are discussed as essential processing stages. Pattern extraction and matching is based on vectors relative to a manually defined region of interest. Provision for enhancing the system to allow fully automatic processing must be made.
- Full Text:
- Authors: Krijer, Hans , Foster, Greg , Bangay, Shaun D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432726 , vital:72895 , https://www.cs.ru.ac.za/research/g99k3906/hans.pdf
- Description: The conventional methods of animal identification can be replaced with a semi-automatic image analysis tool, which distinguishes individuals based on their unique markings. A flexible framework for the analysis must encompass a combination of relevant features with interchangeable animal-specific modules. Developing a Java-ImageJ plug-in alleviates routine functionality, but enforces some degree of conformity. Zebra photographs are used as the initial data under consideration. De-interlacing, adaptive thresholding, smoothing and sharpening are identified as beneficial pre-processing steps. Binarisation and sequential thinning are discussed as essential processing stages. Pattern extraction and matching is based on vectors relative to a manually defined region of interest. Provision for enhancing the system to allow fully automatic processing must be made.
- Full Text:
Designing and implementing a new pulsar timer for the Hartebeesthoek Radio Astronomy Observatory
- Authors: Youthed, Andrew David
- Date: 2008
- Subjects: Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5458 , http://hdl.handle.net/10962/d1005243 , Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Description: This thesis outlines the design and implementation of a single channel, dual polarization pulsar timing instrument for the Hartebeesthoek Radio Astronomy Observatory (HartRAO). The new timer is designed to be an improved, temporary replacement for the existing device which has been in operation for over 20 years. The existing device is no longer reliable and is di±cult to maintain. The new pulsar timer is designed to provide improved functional- ity, higher sampling speed, greater pulse resolution, more °exibility and easier maintenance over the existing device. The new device is also designed to keeping changes to the observation system to a minimum until a full de-dispersion timer can be implemented at theobservatory. The design makes use of an 8-bit Reduced Instruction Set Computer (RISC) micro-processor with external Random Access Memory (RAM). The instrument includes an IEEE-488 subsystem for interfacing the pulsar timer to the observation computer system. The microcontroller software is written in assembler code to ensure optimal loop execution speed and deterministic code execution for the system. The design path is discussed and problems encountered during the design process are highlighted. Final testing of the new instrument indicates an improvement in the sam- pling rate of 13.6 times and a significant reduction in 60Hz interference over the existing instrument.
- Full Text:
- Authors: Youthed, Andrew David
- Date: 2008
- Subjects: Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5458 , http://hdl.handle.net/10962/d1005243 , Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Description: This thesis outlines the design and implementation of a single channel, dual polarization pulsar timing instrument for the Hartebeesthoek Radio Astronomy Observatory (HartRAO). The new timer is designed to be an improved, temporary replacement for the existing device which has been in operation for over 20 years. The existing device is no longer reliable and is di±cult to maintain. The new pulsar timer is designed to provide improved functional- ity, higher sampling speed, greater pulse resolution, more °exibility and easier maintenance over the existing device. The new device is also designed to keeping changes to the observation system to a minimum until a full de-dispersion timer can be implemented at theobservatory. The design makes use of an 8-bit Reduced Instruction Set Computer (RISC) micro-processor with external Random Access Memory (RAM). The instrument includes an IEEE-488 subsystem for interfacing the pulsar timer to the observation computer system. The microcontroller software is written in assembler code to ensure optimal loop execution speed and deterministic code execution for the system. The design path is discussed and problems encountered during the design process are highlighted. Final testing of the new instrument indicates an improvement in the sam- pling rate of 13.6 times and a significant reduction in 60Hz interference over the existing instrument.
- Full Text:
Determination of the optimal water temperature for the culture of juvenile dusky kob Argyrosomus japonicus Temminck and Schlegel 1843:
- Collett, Paul D, Vine, Niall G, Kaiser, Horst, Baxter, Jeremy
- Authors: Collett, Paul D , Vine, Niall G , Kaiser, Horst , Baxter, Jeremy
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142804 , vital:38118 , DOI: 10.1111/j.1365-2109.2008.01960.x
- Description: The effects of temperature on growth, food conversion ratio (FCR) and feeding intensity of juvenile dusky kob Argyrosomus japonicus (23.7±2.6 g fish−1) were assessed over the temperature range 17.5–28.5°C in a 42 day growth trial. Growth increased with increasing temperature up to an optimum after which it declined. Specific growth rates were 2.05% and 1.2% day−1 for the fastest (25.3 °C) and the slowest (17.5 °C) treatments respectively. Food conversion ratio peaked at a lower temperature than growth. Optimal (0.72 kg kg gain−1) and least efficient (1.40 kg kg gain−1) FCR were found at 21.7 and 17.5°C respectively. Feeding intensity was linearly related to temperature within the range of 17.5–28.5°C. These results corresponded to the thermal preference (25–26.4°C) and natural temperature distribution (12–28°C) of South African dusky kob. Determination of the temperature range that does not limit growth is a prerequisite to assess the relationship between growth and environmental variables such as light intensity, feeding regime and stocking density. Consequently, experiments to determine the effects of these environmental variables on growth and aquaculture potential of dusky kob should be conducted at 24–26°C.
- Full Text:
- Authors: Collett, Paul D , Vine, Niall G , Kaiser, Horst , Baxter, Jeremy
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142804 , vital:38118 , DOI: 10.1111/j.1365-2109.2008.01960.x
- Description: The effects of temperature on growth, food conversion ratio (FCR) and feeding intensity of juvenile dusky kob Argyrosomus japonicus (23.7±2.6 g fish−1) were assessed over the temperature range 17.5–28.5°C in a 42 day growth trial. Growth increased with increasing temperature up to an optimum after which it declined. Specific growth rates were 2.05% and 1.2% day−1 for the fastest (25.3 °C) and the slowest (17.5 °C) treatments respectively. Food conversion ratio peaked at a lower temperature than growth. Optimal (0.72 kg kg gain−1) and least efficient (1.40 kg kg gain−1) FCR were found at 21.7 and 17.5°C respectively. Feeding intensity was linearly related to temperature within the range of 17.5–28.5°C. These results corresponded to the thermal preference (25–26.4°C) and natural temperature distribution (12–28°C) of South African dusky kob. Determination of the temperature range that does not limit growth is a prerequisite to assess the relationship between growth and environmental variables such as light intensity, feeding regime and stocking density. Consequently, experiments to determine the effects of these environmental variables on growth and aquaculture potential of dusky kob should be conducted at 24–26°C.
- Full Text:
Developing principles for research about young women and abortion: a feminist analysis of difficulties in current South African studies
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6292 , http://hdl.handle.net/10962/d1014716
- Description: Soon after the first democratic elections in South Africa in 1994, the Choice on Termination of Pregnancy (CTOP) Act of 1996, which legalised abortion for the first time, was passed. Since the introduction of the CTOP, a number of studies have been conducted on abortion in South Africa. Many have taken a health-related focus, but some research on young women and abortion has also been conducted, and it is to this (published) research that this article speaks. Two facts highlight the importance of this kind of research in the context of the abortion debate. Firstly, data from the Department of Health indicate that from 1997 to mid-2006, 12% of women undergoing terminations in the provinces in which age-related data are available were under the age of 18 (Department of Health: 2006). Secondly, the subsection of the Act allowing minors to request abortions without parental consent has caused some controversy. For example, the Christian Lawyers Association filed a suit in the Pretoria High Court in 2003, arguing that the above-mentioned subsection was unconstitutional. Their application was not successful. The research conducted on young women and abortion is etched against a background of change and contradiction in young people’s lives in South Africa. In addition to enabling legislation on termination of pregnancy, which is premised on the rights-based approach of the first democratically elected government of South Africa, various opportunities and challenges define the lives of young women. Specifically in relation to sexual and reproductive health, the Department of Health’s National Adolescent Friendly Clinic Initiative aims to make family planning and other services more accessible and acceptable to young women (Dickson-Tetteh et al., 2001). However,HIV/AIDS and “safe sex” programmes define sex as dangerous and individual young women as responsible for close monitoring of heterosexual spaces. The Child Support Grant, shown to enable functional mothering (Case et al., 2005), has sparked controversy in terms of providing perverse incentives for poor young women to conceive (a claim refuted by the research – Makiwane & Udjo, 2005). Young, black and poor women who conceive are, in particular, stigmatised and teenage pregnancy is in many respects racialised (Macleod & Durrheim, 2002). In this paper I highlight some of the problems in the research conducted on young women and abortion in South Africa since the legalisation of abortion. The specific aim of the paper is, through this analysis, to draw out feminist principles that should be considered in this kind of research. My argument draws on postcolonial feminisms that theorise the multiplicity of oppression along gender and, inter alia, race, class, age and location lines (Macleod, 2006). The paper is premised on the assumption that, in a field as fraught with gendered, race and class politics as abortion, regardless of the method used, researchers need to inspect the ideological implications of their work, and to be vigilant about their scholastic practices, and any claims legitimately made.
- Full Text:
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6292 , http://hdl.handle.net/10962/d1014716
- Description: Soon after the first democratic elections in South Africa in 1994, the Choice on Termination of Pregnancy (CTOP) Act of 1996, which legalised abortion for the first time, was passed. Since the introduction of the CTOP, a number of studies have been conducted on abortion in South Africa. Many have taken a health-related focus, but some research on young women and abortion has also been conducted, and it is to this (published) research that this article speaks. Two facts highlight the importance of this kind of research in the context of the abortion debate. Firstly, data from the Department of Health indicate that from 1997 to mid-2006, 12% of women undergoing terminations in the provinces in which age-related data are available were under the age of 18 (Department of Health: 2006). Secondly, the subsection of the Act allowing minors to request abortions without parental consent has caused some controversy. For example, the Christian Lawyers Association filed a suit in the Pretoria High Court in 2003, arguing that the above-mentioned subsection was unconstitutional. Their application was not successful. The research conducted on young women and abortion is etched against a background of change and contradiction in young people’s lives in South Africa. In addition to enabling legislation on termination of pregnancy, which is premised on the rights-based approach of the first democratically elected government of South Africa, various opportunities and challenges define the lives of young women. Specifically in relation to sexual and reproductive health, the Department of Health’s National Adolescent Friendly Clinic Initiative aims to make family planning and other services more accessible and acceptable to young women (Dickson-Tetteh et al., 2001). However,HIV/AIDS and “safe sex” programmes define sex as dangerous and individual young women as responsible for close monitoring of heterosexual spaces. The Child Support Grant, shown to enable functional mothering (Case et al., 2005), has sparked controversy in terms of providing perverse incentives for poor young women to conceive (a claim refuted by the research – Makiwane & Udjo, 2005). Young, black and poor women who conceive are, in particular, stigmatised and teenage pregnancy is in many respects racialised (Macleod & Durrheim, 2002). In this paper I highlight some of the problems in the research conducted on young women and abortion in South Africa since the legalisation of abortion. The specific aim of the paper is, through this analysis, to draw out feminist principles that should be considered in this kind of research. My argument draws on postcolonial feminisms that theorise the multiplicity of oppression along gender and, inter alia, race, class, age and location lines (Macleod, 2006). The paper is premised on the assumption that, in a field as fraught with gendered, race and class politics as abortion, regardless of the method used, researchers need to inspect the ideological implications of their work, and to be vigilant about their scholastic practices, and any claims legitimately made.
- Full Text:
Development and validation of the Xhosa translations of the Beck Inventories: 1. Challenges of the translation process
- Steele, Gary I, Edwards, David J A
- Authors: Steele, Gary I , Edwards, David J A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6248 , http://hdl.handle.net/10962/d1007866
- Description: This article describes the translation of the Beck Depression Inventory-II, the Beck Hopeless Scale, and the Beck Anxiety Inventory, into Xhosa the language spoken in the Eastern Cape of South Africa. The processes of translation, back-translation and committee discussion failed to yield trustworthy translations because of practical difficulties in working with translators. Critical words and phrases were identified which gave rise to lack of agreement. For each, a range of options was generated and the advantages and disadvantages evaluated in terms of criteria such as conceptual and idiomatic equivalence, and extensiveness of usage. Examples are given of the problems encountered and the way in which final decisions were made. A pilot clinical trial demonstrated the acceptability of the translated Instruments. Two further articles report the psychometric evaluation of the translated scales.
- Full Text:
- Authors: Steele, Gary I , Edwards, David J A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6248 , http://hdl.handle.net/10962/d1007866
- Description: This article describes the translation of the Beck Depression Inventory-II, the Beck Hopeless Scale, and the Beck Anxiety Inventory, into Xhosa the language spoken in the Eastern Cape of South Africa. The processes of translation, back-translation and committee discussion failed to yield trustworthy translations because of practical difficulties in working with translators. Critical words and phrases were identified which gave rise to lack of agreement. For each, a range of options was generated and the advantages and disadvantages evaluated in terms of criteria such as conceptual and idiomatic equivalence, and extensiveness of usage. Examples are given of the problems encountered and the way in which final decisions were made. A pilot clinical trial demonstrated the acceptability of the translated Instruments. Two further articles report the psychometric evaluation of the translated scales.
- Full Text:
Development of a novel in situ CPRG-based biosensor and bioprobe for monitoring coliform β-D-Galactosidase in water polluted by faecal matter
- Authors: Wutor, Victor Collins
- Date: 2008
- Subjects: Biosensors Molecular probes Enterobacteriaceae Feces -- Microbiology Water -- Pollution -- Environmental aspects Environmental monitoring Chromogenic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3944 , http://hdl.handle.net/10962/d1004003
- Description: The ultimate objective of this work was to develop a real-time method for detecting and monitoring β-D-galactosidase as a suitable indicator of the potential presence of total coliform bacteria in water environments. Preliminary comparison of the chromogenic substrate, chlorophenol red β-D-galactopyranoside and the fluorogenic substrate, MuGAL, revealed unreliable results with the fluorogenic technique due to interference from compounds commonly found in environmental water samples. Thus, the chromogenic assay was further explored. Hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside by β-D-galactosidase to yield chlorophenol red was the basis of this assay. Fundamental studies with chlorophenol red β-Dgalactopyranoside showed that β-D-galactosidase occurs extracellularly and in low concentrations in the polluted water environment. A direct correlation between enzyme activity and an increase in environmental water sample volume, as well as enzyme activity with total coliform colony forming unit counts were observed. Spectrophotometric detection was achieved within a maximum period of 24 h with a limit of detection level of 1 colony forming unit 100 ml[superscript -1]. This enzyme also exhibited physical and kinetic properties different from those of the pure commercially available β-D-galactosidase. Cell permeabilisation was not required for releasing enzymes into the extracellular environment. PEG 20 000 offered the best option for concentrating β-D-galactosidase. The source of β-D-galactosidase in the polluted environmental water samples was confirmed as Escherichia coli through SDS-PAGE, tryptic mapping and MALDI-TOF, thus justifying the further use of this method for detecting and/or monitoring total coliforms. Several compounds and metal ions commonly found in environmental water samples (as well as those used in water treatment processes) did have an effect on β-D-galactosidase. All the divalent cations except Mg [superscript 2+], at the concentrations studied, inhibited the relative activity of β-D-galactosidase in both commercial β-D-galactosidase and environmental samples. Immobilisation of chlorophenol red β-D-galactopyranoside onto a solid support material for the development of a strip bioprobe was unsuccessful, even though the nylon support material yielded some positive results. A monthly (seasonal) variation in β-Dgalactosidase activity from the environmental water samples was observed, with the highest activity coinciding with the highest monthly temperatures. Electro-oxidative detection and/or monitoring of chlorophenol red was possible. Chlorophenol red detection was linear over a wide range of concentrations (0.001-0.01 μg ml[superscript -1]). Interference by chlorophenol red β-D-galactopyranoside in the reduction window affected analysis. A range of phthalocyanine metal complexes were studied in an attempt to reduce fouling and/or increase the sensitivity of the biosensor. The selected phthalocyanine metal complexes were generally sensitive to changes in pH with a reduction in sensitivity from acidic pH to alkaline pH. The tetrasulphonated phthalocyanine metal complex of copper was, however, more stable with a minimum change of sensitivity. The phthalocyanine metal complexes were generally stable to changes in temperature. While only two consecutive scans were possible with the unmodified glassy carbon electrode, 77 consecutive scans were performed successfully with the CuPc-modified glassy carbon electrode. Among the phthalocyanine metal complexes studied, the CuPc-modified glassy carbon electrode therefore provided excellent results for the development of a biosensor. The CuPc modified-glassy carbon electrode detected 1 colony forming unit 100 ml[superscript -1] in 15 minutes, while the plain unmodified glassy carbon electrode required 6 hours to detect the equivalent number of colony forming units. CoPc, ZnPc and CuTSPc required 2, 2.25 and 1.75 h, respectively, to detect the same numbers of colony forming units. The CuPcmodified glassy carbon electrode detected 40 colony forming units 100 ml[superscript -1] instantly. In general, a direct correlation between colony forming units and current generated in the sensor was observed (R2=0.92). A higher correlation coefficient of 0.99 for 0-30 coliform colony forming units 100 ml[superscript -1] was determined. Current was detected in some water samples which did not show any colony forming units on the media, probably due to the phenomenon of viable but non-culturable bacteria, which is the major disadvantage encountered in the use of media for detecting indicator microorganisms. This novel biosensor therefore presents a very robust and sensitive technique for the detection and/or monitoring of coliform bacterial activity in water.
- Full Text:
- Authors: Wutor, Victor Collins
- Date: 2008
- Subjects: Biosensors Molecular probes Enterobacteriaceae Feces -- Microbiology Water -- Pollution -- Environmental aspects Environmental monitoring Chromogenic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3944 , http://hdl.handle.net/10962/d1004003
- Description: The ultimate objective of this work was to develop a real-time method for detecting and monitoring β-D-galactosidase as a suitable indicator of the potential presence of total coliform bacteria in water environments. Preliminary comparison of the chromogenic substrate, chlorophenol red β-D-galactopyranoside and the fluorogenic substrate, MuGAL, revealed unreliable results with the fluorogenic technique due to interference from compounds commonly found in environmental water samples. Thus, the chromogenic assay was further explored. Hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside by β-D-galactosidase to yield chlorophenol red was the basis of this assay. Fundamental studies with chlorophenol red β-Dgalactopyranoside showed that β-D-galactosidase occurs extracellularly and in low concentrations in the polluted water environment. A direct correlation between enzyme activity and an increase in environmental water sample volume, as well as enzyme activity with total coliform colony forming unit counts were observed. Spectrophotometric detection was achieved within a maximum period of 24 h with a limit of detection level of 1 colony forming unit 100 ml[superscript -1]. This enzyme also exhibited physical and kinetic properties different from those of the pure commercially available β-D-galactosidase. Cell permeabilisation was not required for releasing enzymes into the extracellular environment. PEG 20 000 offered the best option for concentrating β-D-galactosidase. The source of β-D-galactosidase in the polluted environmental water samples was confirmed as Escherichia coli through SDS-PAGE, tryptic mapping and MALDI-TOF, thus justifying the further use of this method for detecting and/or monitoring total coliforms. Several compounds and metal ions commonly found in environmental water samples (as well as those used in water treatment processes) did have an effect on β-D-galactosidase. All the divalent cations except Mg [superscript 2+], at the concentrations studied, inhibited the relative activity of β-D-galactosidase in both commercial β-D-galactosidase and environmental samples. Immobilisation of chlorophenol red β-D-galactopyranoside onto a solid support material for the development of a strip bioprobe was unsuccessful, even though the nylon support material yielded some positive results. A monthly (seasonal) variation in β-Dgalactosidase activity from the environmental water samples was observed, with the highest activity coinciding with the highest monthly temperatures. Electro-oxidative detection and/or monitoring of chlorophenol red was possible. Chlorophenol red detection was linear over a wide range of concentrations (0.001-0.01 μg ml[superscript -1]). Interference by chlorophenol red β-D-galactopyranoside in the reduction window affected analysis. A range of phthalocyanine metal complexes were studied in an attempt to reduce fouling and/or increase the sensitivity of the biosensor. The selected phthalocyanine metal complexes were generally sensitive to changes in pH with a reduction in sensitivity from acidic pH to alkaline pH. The tetrasulphonated phthalocyanine metal complex of copper was, however, more stable with a minimum change of sensitivity. The phthalocyanine metal complexes were generally stable to changes in temperature. While only two consecutive scans were possible with the unmodified glassy carbon electrode, 77 consecutive scans were performed successfully with the CuPc-modified glassy carbon electrode. Among the phthalocyanine metal complexes studied, the CuPc-modified glassy carbon electrode therefore provided excellent results for the development of a biosensor. The CuPc modified-glassy carbon electrode detected 1 colony forming unit 100 ml[superscript -1] in 15 minutes, while the plain unmodified glassy carbon electrode required 6 hours to detect the equivalent number of colony forming units. CoPc, ZnPc and CuTSPc required 2, 2.25 and 1.75 h, respectively, to detect the same numbers of colony forming units. The CuPcmodified glassy carbon electrode detected 40 colony forming units 100 ml[superscript -1] instantly. In general, a direct correlation between colony forming units and current generated in the sensor was observed (R2=0.92). A higher correlation coefficient of 0.99 for 0-30 coliform colony forming units 100 ml[superscript -1] was determined. Current was detected in some water samples which did not show any colony forming units on the media, probably due to the phenomenon of viable but non-culturable bacteria, which is the major disadvantage encountered in the use of media for detecting indicator microorganisms. This novel biosensor therefore presents a very robust and sensitive technique for the detection and/or monitoring of coliform bacterial activity in water.
- Full Text:
Disgrace as J.M.Coetzee's Tempest
- Authors: Wright, Laurence
- Date: 2008
- Language: English
- Type: Book chapter
- Identifier: vital:7030 , http://hdl.handle.net/10962/d1007217
- Description: Amid the deluge of criticism and commentary evoked by Disgrace, quite remarkably nobody has noticed that the book re-engages exactly the energies Shakespeare deployed in The Tempest, a play which has become an icon, if not the icon, of colonial and post-colonial studies.
- Full Text:
- Authors: Wright, Laurence
- Date: 2008
- Language: English
- Type: Book chapter
- Identifier: vital:7030 , http://hdl.handle.net/10962/d1007217
- Description: Amid the deluge of criticism and commentary evoked by Disgrace, quite remarkably nobody has noticed that the book re-engages exactly the energies Shakespeare deployed in The Tempest, a play which has become an icon, if not the icon, of colonial and post-colonial studies.
- Full Text:
Do environmental factors influence the movement of estuarine fish? A case study using acoustic telemetry
- Childs, Amber-Robyn, Cowley, Paul D, Næsje, T F, Booth, Anthony J, Thorstad, Eva B, Økland, F
- Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Thorstad, Eva B , Økland, F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6772 , http://hdl.handle.net/10962/d1008070
- Description: Telemetry methods were used to investigate the influence of selected environmental variables on the position and movement of an estuarine-dependent haemulid, the spotted grunter Pomadasys commersonnii (Lacepède 1801), in the Great Fish Estuary, South Africa. Forty individuals (263–698 mm TL) were surgically implanted with acoustic coded transmitters and manually tracked during two periods (7 February to 24 March 2003; n = 20 and 29 September to 15 November 2003; n = 20). Real-time data revealed that spotted grunter are euryhaline (0–37) and are able to tolerate large variations in turbidity (4–356 FTU) and temperature (16–30 °C). However, the fish altered their position in response to large fluctuations in salinity, temperature and turbidity, which are characteristic of tidal estuarine environments. Furthermore, tidal phase had a strong influence on the position of spotted grunter in the estuary.
- Full Text:
- Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Thorstad, Eva B , Økland, F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6772 , http://hdl.handle.net/10962/d1008070
- Description: Telemetry methods were used to investigate the influence of selected environmental variables on the position and movement of an estuarine-dependent haemulid, the spotted grunter Pomadasys commersonnii (Lacepède 1801), in the Great Fish Estuary, South Africa. Forty individuals (263–698 mm TL) were surgically implanted with acoustic coded transmitters and manually tracked during two periods (7 February to 24 March 2003; n = 20 and 29 September to 15 November 2003; n = 20). Real-time data revealed that spotted grunter are euryhaline (0–37) and are able to tolerate large variations in turbidity (4–356 FTU) and temperature (16–30 °C). However, the fish altered their position in response to large fluctuations in salinity, temperature and turbidity, which are characteristic of tidal estuarine environments. Furthermore, tidal phase had a strong influence on the position of spotted grunter in the estuary.
- Full Text:
Drought responses of C3 and C4 (NADP-ME) Panicoid grasses
- Authors: Frole, Kristen Marie
- Date: 2008
- Subjects: Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4193 , http://hdl.handle.net/10962/d1003762 , Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Description: The success of C₄ plants lies in their ability to concentrate CO₂ at the site of Rubisco thereby conferring greater efficiencies of light, water and nitrogen. Such characteristics should advantage C₄ plants in arid, hot environments. However, not all C₄ subtypes are drought tolerant. The relative abundance of NADP-ME species declines with increasing aridity. Furthermore, selected species have been demonstrated as being susceptible to severe drought showing metabolic limitations of photosynthesis. However there is a lack of phylogenetic control with many of these studies. The aims of this study were to determine whether the NADP-ME subtype was inherently susceptible to drought by comparing six closely related C₃ and C₄ (NADP-ME) Panicoid grasses. Gas exchange measurements were made during a natural rainless period and a controlled drought / rewatering event. Prior to water stress, the C₄ species had higher assimilation rates (A), and water use efficiencies (WUE[subscript leaf]) than the C₃ species, while transpiration rates (E) and stomatal conductances (g[subscript s]) were similar. At low soil water content, the C₃ species reduced gs by a greater extent than the C₄ species, which maintained higher E during the driest periods. The C₄ species showed proportionally greater reductions in A than the C₃ species and hence lost their WUE[subscript leaf] and photosynthetic advantage. CO₂ response curves showed that metabolic limitation was responsible for a greater decrease in A in the C₄ type than the C₃ type during progressive drought. Upon re-watering, photosynthetic recovery was quicker in the C species than the C₄ species. Results from whole plant measurements showed that the C₄ type had a significant whole plant water use efficiency advantage over the C₃ type under well-watered conditions that was lost during severe drought due to a greater loss of leaf area through leaf mortality rather than reductions in plant level transpiration rates. The C₃ type had xylem characteristics that enhanced water-conducting efficiency, but made them vulnerable to drought. This is in contrast to the safer xylem qualities of the C₄ type, which permitted the endurance of more negative leaf water potentials than the C₃ type during low soil water content. Thus, the vulnerability of photosynthesis to severe drought in NADP-ME species potentially explains why NADP-ME species abundance around the world decreases with decreasing rainfall.
- Full Text:
- Authors: Frole, Kristen Marie
- Date: 2008
- Subjects: Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4193 , http://hdl.handle.net/10962/d1003762 , Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Description: The success of C₄ plants lies in their ability to concentrate CO₂ at the site of Rubisco thereby conferring greater efficiencies of light, water and nitrogen. Such characteristics should advantage C₄ plants in arid, hot environments. However, not all C₄ subtypes are drought tolerant. The relative abundance of NADP-ME species declines with increasing aridity. Furthermore, selected species have been demonstrated as being susceptible to severe drought showing metabolic limitations of photosynthesis. However there is a lack of phylogenetic control with many of these studies. The aims of this study were to determine whether the NADP-ME subtype was inherently susceptible to drought by comparing six closely related C₃ and C₄ (NADP-ME) Panicoid grasses. Gas exchange measurements were made during a natural rainless period and a controlled drought / rewatering event. Prior to water stress, the C₄ species had higher assimilation rates (A), and water use efficiencies (WUE[subscript leaf]) than the C₃ species, while transpiration rates (E) and stomatal conductances (g[subscript s]) were similar. At low soil water content, the C₃ species reduced gs by a greater extent than the C₄ species, which maintained higher E during the driest periods. The C₄ species showed proportionally greater reductions in A than the C₃ species and hence lost their WUE[subscript leaf] and photosynthetic advantage. CO₂ response curves showed that metabolic limitation was responsible for a greater decrease in A in the C₄ type than the C₃ type during progressive drought. Upon re-watering, photosynthetic recovery was quicker in the C species than the C₄ species. Results from whole plant measurements showed that the C₄ type had a significant whole plant water use efficiency advantage over the C₃ type under well-watered conditions that was lost during severe drought due to a greater loss of leaf area through leaf mortality rather than reductions in plant level transpiration rates. The C₃ type had xylem characteristics that enhanced water-conducting efficiency, but made them vulnerable to drought. This is in contrast to the safer xylem qualities of the C₄ type, which permitted the endurance of more negative leaf water potentials than the C₃ type during low soil water content. Thus, the vulnerability of photosynthesis to severe drought in NADP-ME species potentially explains why NADP-ME species abundance around the world decreases with decreasing rainfall.
- Full Text:
Dungamanzi/stirring waters: Tsonga and Shangaan art from southern Africa, Nessa Leibhammer (Ed.): book reviews
- Authors: Simbao, Ruth K
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147358 , vital:38629 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC31053
- Description: A woman known as Nkoma We Lwandle (Cow of the Ocean) and a man, Dunga Manzi (Stirring Waters), are remembered as the first Tsonga diviners. Trained by Nzunzu - a powerful water serpent - they were pulled into a lake for a few months and later emerged as influential healers. Such stories (like the one relayed by Dederen of a young girl, Nsatimuni, who also temporarily disappeared into a lake) represent 'death' and 'rebirth', reflecting Arnold van Gennep's (1909) well-known schema of rites de passage: séparation, marge, and agrégation. Separated from daily life, these characters sink into another world where people breathe in water like a foetus in the liquid depths of a womb, evoking impending new birth (p. 171).
- Full Text:
- Authors: Simbao, Ruth K
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147358 , vital:38629 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC31053
- Description: A woman known as Nkoma We Lwandle (Cow of the Ocean) and a man, Dunga Manzi (Stirring Waters), are remembered as the first Tsonga diviners. Trained by Nzunzu - a powerful water serpent - they were pulled into a lake for a few months and later emerged as influential healers. Such stories (like the one relayed by Dederen of a young girl, Nsatimuni, who also temporarily disappeared into a lake) represent 'death' and 'rebirth', reflecting Arnold van Gennep's (1909) well-known schema of rites de passage: séparation, marge, and agrégation. Separated from daily life, these characters sink into another world where people breathe in water like a foetus in the liquid depths of a womb, evoking impending new birth (p. 171).
- Full Text:
Eco-Schools and the quality of education in South Africa: Realising the potential
- Authors: Rosenberg, Eureta
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370511 , vital:66349 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122759"
- Description: Eco-Schools South Africa is increasingly being used by external partners as a framework for supporting environmental education in schools. This paper shares the findings of a recent evaluation of the programme in relation to the quality of education in South African schools. Do Eco-Schools activities help to improve the conditions of teaching and learning? Or do they take teachers and students away from their core focus? Evaluation of learner and teacher work in Eco-Schools found signs of the quality problems that currently plague the schools system, and there is evidence that the programme can add to the complexity to which many teachers struggle to respond. The evaluation also found, however, that the programme has significant potential to improve conditions for teaching and learning. The paper is an opportunity to reflect on how environmental education support for schools, in general, and Eco-Schools South Africa, in particular, can detract from and strengthen teaching and learning.
- Full Text:
- Authors: Rosenberg, Eureta
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370511 , vital:66349 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122759"
- Description: Eco-Schools South Africa is increasingly being used by external partners as a framework for supporting environmental education in schools. This paper shares the findings of a recent evaluation of the programme in relation to the quality of education in South African schools. Do Eco-Schools activities help to improve the conditions of teaching and learning? Or do they take teachers and students away from their core focus? Evaluation of learner and teacher work in Eco-Schools found signs of the quality problems that currently plague the schools system, and there is evidence that the programme can add to the complexity to which many teachers struggle to respond. The evaluation also found, however, that the programme has significant potential to improve conditions for teaching and learning. The paper is an opportunity to reflect on how environmental education support for schools, in general, and Eco-Schools South Africa, in particular, can detract from and strengthen teaching and learning.
- Full Text:
Ecological role of free-living bacteria in the microbial food web of the temporarily open/closed East Kleinemonde Estuary, South Africa
- Authors: Allan, Elizabeth Louise
- Date: 2008
- Subjects: Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5666 , http://hdl.handle.net/10962/d1005351 , Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Description: The main aim of this study was to assess the “top-down” and “bottom-up” control of bacterial production in the small temporarily open/closed East Kleinemonde Estuary, situated on the south-eastern coastline of southern Africa. Spatial and temporal patterns in bacterial abundance, biomass and production and the importance of abiotic and biotic factors were investigated over the period May 2006 to April 2007. The trophic interactions between bacteria, phytoplankton, nanoflagellates (< 20 μm), microzooplankton (< 200 μm) and mesozooplankton (< 2 000 μm) were investigated during winter and summer. Bacterial abundance, biomass and production ranged between 1.00 × 10⁹ and 4.93 × 10⁹ cells 1⁻¹, 32.4 and 109 μg C 1⁻¹ and 0.01 and 1.99 μg C 1⁻¹ h⁻¹, respectively. With a few exceptions there were no spatial patterns in the values. Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Nanoflagellate and bacterial abundances were significantly correlated to one another (lower reaches: r = 0.818, p < 0.001; middle reaches: r = 0.628, p < 0.001; upper reaches: r = 0.484, p < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the mean number of virus particles within each bacterial cell during this study demonstrated no temporal or spatial patterns and ranged from 0.5 to 6.1 % and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% of the total which suggests that viral lysis represented a very important source of bacterial mortality during this study. The biological interactions between the selected components of the plankton community demonstrated that among the heterotrophic components of the plankton, the nanoflagellates were identified as the most important consumers of bacteria and small phytoplankton cells (< 20 μm). In the presence of microzooplankton the impact of the nanoflagellates on both the bacteria and phytoplankton was reduced, indicating that larger heterotrophs were preying upon the nanoflagellates. Mesozooplankton, however, appeared to exert the greatest impact on nanoflagellates. In the cascading experiments, the data suggest that mesozooplankton consume nanoflagellates, which resulted in a decrease in the predation impact of these organisms on the bacteria. This result is consistent with predator-prey cascades. The presence of the larger heterotrophs therefore, mediates the interactions between the primary bacterivores, the nanoflagellates, and the bacteria within the temporarily open/closed East Kleinemonde Estuary.
- Full Text:
- Authors: Allan, Elizabeth Louise
- Date: 2008
- Subjects: Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5666 , http://hdl.handle.net/10962/d1005351 , Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Description: The main aim of this study was to assess the “top-down” and “bottom-up” control of bacterial production in the small temporarily open/closed East Kleinemonde Estuary, situated on the south-eastern coastline of southern Africa. Spatial and temporal patterns in bacterial abundance, biomass and production and the importance of abiotic and biotic factors were investigated over the period May 2006 to April 2007. The trophic interactions between bacteria, phytoplankton, nanoflagellates (< 20 μm), microzooplankton (< 200 μm) and mesozooplankton (< 2 000 μm) were investigated during winter and summer. Bacterial abundance, biomass and production ranged between 1.00 × 10⁹ and 4.93 × 10⁹ cells 1⁻¹, 32.4 and 109 μg C 1⁻¹ and 0.01 and 1.99 μg C 1⁻¹ h⁻¹, respectively. With a few exceptions there were no spatial patterns in the values. Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Nanoflagellate and bacterial abundances were significantly correlated to one another (lower reaches: r = 0.818, p < 0.001; middle reaches: r = 0.628, p < 0.001; upper reaches: r = 0.484, p < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the mean number of virus particles within each bacterial cell during this study demonstrated no temporal or spatial patterns and ranged from 0.5 to 6.1 % and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% of the total which suggests that viral lysis represented a very important source of bacterial mortality during this study. The biological interactions between the selected components of the plankton community demonstrated that among the heterotrophic components of the plankton, the nanoflagellates were identified as the most important consumers of bacteria and small phytoplankton cells (< 20 μm). In the presence of microzooplankton the impact of the nanoflagellates on both the bacteria and phytoplankton was reduced, indicating that larger heterotrophs were preying upon the nanoflagellates. Mesozooplankton, however, appeared to exert the greatest impact on nanoflagellates. In the cascading experiments, the data suggest that mesozooplankton consume nanoflagellates, which resulted in a decrease in the predation impact of these organisms on the bacteria. This result is consistent with predator-prey cascades. The presence of the larger heterotrophs therefore, mediates the interactions between the primary bacterivores, the nanoflagellates, and the bacteria within the temporarily open/closed East Kleinemonde Estuary.
- Full Text:
Ecological thinking: Schopenhauer, J M Coetzee and who we are in the world
- Authors: Wright, Laurence
- Date: 2008
- Language: English
- Type: text , article
- Identifier: vital:7031 , http://hdl.handle.net/10962/d1007362 , https://doi.org/10.5848/CSP.0926.00001
- Description: preprint , For the ecological agenda to make substantive progress, we will have to see powerful people and social agencies turning away from the ecological insanity that threatens us all, and for this to happen, people need to embrace voluntary renunciation, on the understanding that this is not self-sacrifice, but a different and more satisfying way of being in the world. The paper offers some thought, provoked by reading J.M. Coetzee and Arthur Schopenhauer, about what would make this change possible, what might enable it; and secondly why it is implausible that any such ideal might actually come to pass.
- Full Text:
- Authors: Wright, Laurence
- Date: 2008
- Language: English
- Type: text , article
- Identifier: vital:7031 , http://hdl.handle.net/10962/d1007362 , https://doi.org/10.5848/CSP.0926.00001
- Description: preprint , For the ecological agenda to make substantive progress, we will have to see powerful people and social agencies turning away from the ecological insanity that threatens us all, and for this to happen, people need to embrace voluntary renunciation, on the understanding that this is not self-sacrifice, but a different and more satisfying way of being in the world. The paper offers some thought, provoked by reading J.M. Coetzee and Arthur Schopenhauer, about what would make this change possible, what might enable it; and secondly why it is implausible that any such ideal might actually come to pass.
- Full Text:
Ectomycorrhizas in association with Pinus patula in Sabie, South Africa
- Hawley, Greer L, Taylor, A F S, Dames, Joanna F
- Authors: Hawley, Greer L , Taylor, A F S , Dames, Joanna F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6475 , http://hdl.handle.net/10962/d1006163 , http://www.scielo.org.za/scielo.php?pid=S0038-23532008000400011&script=sci_arttext
- Description: Forestry is an economically important industry in South Africa,involving extensive exotic plantations of Eucalyptus, Pinus and Acacia species. These tree species have fungal associations, such as ectomycorrhizas, that have become locally naturalized. The forestry industry is increasingly faced with problems of long-term sustainability, increasing soil acidity and depletion of soil nutrients. It is, therefore, essential that the fundamental importance of the ectomycorrhizal (ECM) symbioses in the nutrient cycling, growth, health and survival of these tree species should not be ignored. Research on the species diversity of ECM fungi associated with forestry plant species has been hampered by the difficulty of identifying the fungi involved in the symbiosis. This investigation focused on the ECM fungi associated with Pinus patula (Schlecht. et Cham.) grown in managed plantations in the Sabie region, Mpumalanga province, South Africa. ECM roots were morphotyped and DNA was extracted. The internal transcribed spacer (ITS) region was amplified using the ITS 1F and ITS 4 primers. The sequences were BLASTed using the GenBank and UNITE databases. Twenty-seven extractions were successfully amplified representing 17 different morphotypes. Of the 27 sequences, 21 were identified as ECM fungi and, from the BLAST results, eleven different ECM species could be identified. Selected ECM root types were morphologically and anatomically described according to root morphology, mantle structure, specialized hyphae and rhizomorph arrangement. Seven dominant field types were described and identified as two Amanita species, Scleroderma citrinum, a suilloid species, Thelephora terrestris, a tometelloid species and one resembled an Albatrellus species.
- Full Text:
- Authors: Hawley, Greer L , Taylor, A F S , Dames, Joanna F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6475 , http://hdl.handle.net/10962/d1006163 , http://www.scielo.org.za/scielo.php?pid=S0038-23532008000400011&script=sci_arttext
- Description: Forestry is an economically important industry in South Africa,involving extensive exotic plantations of Eucalyptus, Pinus and Acacia species. These tree species have fungal associations, such as ectomycorrhizas, that have become locally naturalized. The forestry industry is increasingly faced with problems of long-term sustainability, increasing soil acidity and depletion of soil nutrients. It is, therefore, essential that the fundamental importance of the ectomycorrhizal (ECM) symbioses in the nutrient cycling, growth, health and survival of these tree species should not be ignored. Research on the species diversity of ECM fungi associated with forestry plant species has been hampered by the difficulty of identifying the fungi involved in the symbiosis. This investigation focused on the ECM fungi associated with Pinus patula (Schlecht. et Cham.) grown in managed plantations in the Sabie region, Mpumalanga province, South Africa. ECM roots were morphotyped and DNA was extracted. The internal transcribed spacer (ITS) region was amplified using the ITS 1F and ITS 4 primers. The sequences were BLASTed using the GenBank and UNITE databases. Twenty-seven extractions were successfully amplified representing 17 different morphotypes. Of the 27 sequences, 21 were identified as ECM fungi and, from the BLAST results, eleven different ECM species could be identified. Selected ECM root types were morphologically and anatomically described according to root morphology, mantle structure, specialized hyphae and rhizomorph arrangement. Seven dominant field types were described and identified as two Amanita species, Scleroderma citrinum, a suilloid species, Thelephora terrestris, a tometelloid species and one resembled an Albatrellus species.
- Full Text:
Editorial: authorship and responsibility [African Entomology]
- Authors: Villet, Martin H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6851 , http://hdl.handle.net/10962/d1011132
- Description: Editorial service is a privilege in many senses: editors have a much broader view of disciplinary practices than most of their colleagues; they see work from more institutions; and are privy to manuscripts in all states of fitness for publication. The spectrum of practice is eye-opening, and editors are placed in a position of stewardship, and often mentorship, that inevitably focuses attention on quality assurance and ethics (Lawrence 2003; Bulger 2004; Grieger 2005; Graf et al. 2007). Recently, the Committee on Scholarly Publishing in South Africa, a body within the Academy of Science of South Africa (ASSAf), has drafted Guidelines for best practice in editorial discretion and peer review for South African scholarly journals to assist editors.
- Full Text:
- Authors: Villet, Martin H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6851 , http://hdl.handle.net/10962/d1011132
- Description: Editorial service is a privilege in many senses: editors have a much broader view of disciplinary practices than most of their colleagues; they see work from more institutions; and are privy to manuscripts in all states of fitness for publication. The spectrum of practice is eye-opening, and editors are placed in a position of stewardship, and often mentorship, that inevitably focuses attention on quality assurance and ethics (Lawrence 2003; Bulger 2004; Grieger 2005; Graf et al. 2007). Recently, the Committee on Scholarly Publishing in South Africa, a body within the Academy of Science of South Africa (ASSAf), has drafted Guidelines for best practice in editorial discretion and peer review for South African scholarly journals to assist editors.
- Full Text:
Educated mother-tongue South African English: A corpus approach
- Adendorff, Ralph, de Klerk, Vivian A, de Vos, Mark, Hunt, Sally, Simango, Ronald, Todd, Louise, Niesler, Thomas
- Authors: Adendorff, Ralph , de Klerk, Vivian A , de Vos, Mark , Hunt, Sally , Simango, Ronald , Todd, Louise , Niesler, Thomas
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124352 , vital:35597 , https://doi.org/10.1080/10228190608566261
- Description: South Africa is anecdotally known for its complex system of speech varieties correlating with variables such as ethnicity, first language, class and education. These intuitions (e.g. Lass 1990) require further investigation, especially in the context of a changing South Africa where language variety plays a key role in identifying social, economic and ethnic group membership. Thus, in this research, the extent to which these variables play a role in variety is explored using a corpus approach (the nature of class and race in the corpus is discussed more fully later in the article). The corpus project, focusing primarily on accent, has been undertaken by members of the Department of English Language and Linguistics at Rhodes University in South Africa, collaborating with staff from the Department of Electrical and Electronic Engineering from Stellenbosch University, South Africa. A corpus (the first of its kind) is being compiled, comprising the speech of educated, white, mother-tongue speakers of South African English (as distinct from Afrikaans English, Indian English, and the second language (L2) varieties of English used by speakers of indigenous African languages), and data collection is well under way. This short article aims to describe the aims of the project, and the methodological approach which underpins it, as well as to highlight some of the more problematic aspects of the research.
- Full Text:
- Authors: Adendorff, Ralph , de Klerk, Vivian A , de Vos, Mark , Hunt, Sally , Simango, Ronald , Todd, Louise , Niesler, Thomas
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124352 , vital:35597 , https://doi.org/10.1080/10228190608566261
- Description: South Africa is anecdotally known for its complex system of speech varieties correlating with variables such as ethnicity, first language, class and education. These intuitions (e.g. Lass 1990) require further investigation, especially in the context of a changing South Africa where language variety plays a key role in identifying social, economic and ethnic group membership. Thus, in this research, the extent to which these variables play a role in variety is explored using a corpus approach (the nature of class and race in the corpus is discussed more fully later in the article). The corpus project, focusing primarily on accent, has been undertaken by members of the Department of English Language and Linguistics at Rhodes University in South Africa, collaborating with staff from the Department of Electrical and Electronic Engineering from Stellenbosch University, South Africa. A corpus (the first of its kind) is being compiled, comprising the speech of educated, white, mother-tongue speakers of South African English (as distinct from Afrikaans English, Indian English, and the second language (L2) varieties of English used by speakers of indigenous African languages), and data collection is well under way. This short article aims to describe the aims of the project, and the methodological approach which underpins it, as well as to highlight some of the more problematic aspects of the research.
- Full Text:
Education in the wetlands and wetlands in the education: a case of contextualizing primary/basic education in Tanzania
- Authors: Hogan, Alice Rosemary
- Date: 2008
- Subjects: Education -- Tanzania Environmental education -- Tanzania Education, Rural -- Tanzania Education -- Curricula -- Tanzania Community and school -- Tanzania
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1504 , http://hdl.handle.net/10962/d1003386
- Description: This dissertation describes an action research case study carried out at a sub-village school at Nyamakurukuru, Utete, Rufiji District, Tanzania. The study was a fully independent research activity funded and led by a female Irish environmental and community specialist who has fifteen years experience of working in rural Tanzania, five of which were in Rufiji District. The aim of the action research was to engage a community of villagers, teachers, students and district officers in a participatory process to adapt a module of a school curriculum to the local context, and teach it in order to describe one way in which contextualization, using local and indigenous knowledge and active discovery teaching-learning processes, can be done. The major research question, which I wished to answer for one specific case, was: Does integrating local environmental cultural knowledge into formal schooling contribute to curriculum relevance? If so, in what way? This document describes the background and context of the research, the motivation and the theoretical basis for the work, the methodology and methods, and the action research process itself. The results are interpreted and discussed in the light of current theoretical perspectives on education and environmental education. The main findings within the case are that: Contextualization improved relevance of education and thus its quality by: • breaking through traditional frames/barriers between teachers and students, students and elders and community and teachers, • allowing formal education to take place outside of the school, • necessitating a change in pedagogy1 to more learner-centered, discovery methods, • allowing indigenous knowledge to come into the classroom, • stimulating creativity and increased confidence, and • bringing local socio-political environmental issues into the classroom. This study provides a case example of how education processes, when engaging local cultural knowledge, can improve the relevance, and thus an aspect of the quality of teaching and learning in school-community contexts, while providing a conduit for integrating environmental education into the formal school curriculum. It provides insights into the key issue of relevance which currently faces educators of children in wetlands in Tanzania. Recommendations were made for the case studied and may be useful beyond the boundaries of the case: • Give more explicit government policy and strategic support for community involvement in educational content–epistemologies and pedagogies. • Weaken framing (hierarchical power positions) to encourage greater partnership between school, home and community to improve relevance. • Investigate the provision of education beyond schools. • Provide practical teacher and community training on use of learner-centered, discovery and active pedagogies. • Provide teacher and community education on biodiversity and the environment. • Provide relevant reference texts and research data on the ecology, biodiversity, vegetation, hydrology, agriculture, sociology, history and other relevant subjects. • Officially nurture a culture that learning should be enjoyable. • Allow the curriculum freedom, in these times of increasing risk for rural tropical wetland communities, to make the curriculum fit the local issues rather than vice versa. • Nurture critical analysis of the curriculum in local pedagogic discourse i.e., at the local contextualization level of the home, community and school.
- Full Text:
- Authors: Hogan, Alice Rosemary
- Date: 2008
- Subjects: Education -- Tanzania Environmental education -- Tanzania Education, Rural -- Tanzania Education -- Curricula -- Tanzania Community and school -- Tanzania
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1504 , http://hdl.handle.net/10962/d1003386
- Description: This dissertation describes an action research case study carried out at a sub-village school at Nyamakurukuru, Utete, Rufiji District, Tanzania. The study was a fully independent research activity funded and led by a female Irish environmental and community specialist who has fifteen years experience of working in rural Tanzania, five of which were in Rufiji District. The aim of the action research was to engage a community of villagers, teachers, students and district officers in a participatory process to adapt a module of a school curriculum to the local context, and teach it in order to describe one way in which contextualization, using local and indigenous knowledge and active discovery teaching-learning processes, can be done. The major research question, which I wished to answer for one specific case, was: Does integrating local environmental cultural knowledge into formal schooling contribute to curriculum relevance? If so, in what way? This document describes the background and context of the research, the motivation and the theoretical basis for the work, the methodology and methods, and the action research process itself. The results are interpreted and discussed in the light of current theoretical perspectives on education and environmental education. The main findings within the case are that: Contextualization improved relevance of education and thus its quality by: • breaking through traditional frames/barriers between teachers and students, students and elders and community and teachers, • allowing formal education to take place outside of the school, • necessitating a change in pedagogy1 to more learner-centered, discovery methods, • allowing indigenous knowledge to come into the classroom, • stimulating creativity and increased confidence, and • bringing local socio-political environmental issues into the classroom. This study provides a case example of how education processes, when engaging local cultural knowledge, can improve the relevance, and thus an aspect of the quality of teaching and learning in school-community contexts, while providing a conduit for integrating environmental education into the formal school curriculum. It provides insights into the key issue of relevance which currently faces educators of children in wetlands in Tanzania. Recommendations were made for the case studied and may be useful beyond the boundaries of the case: • Give more explicit government policy and strategic support for community involvement in educational content–epistemologies and pedagogies. • Weaken framing (hierarchical power positions) to encourage greater partnership between school, home and community to improve relevance. • Investigate the provision of education beyond schools. • Provide practical teacher and community training on use of learner-centered, discovery and active pedagogies. • Provide teacher and community education on biodiversity and the environment. • Provide relevant reference texts and research data on the ecology, biodiversity, vegetation, hydrology, agriculture, sociology, history and other relevant subjects. • Officially nurture a culture that learning should be enjoyable. • Allow the curriculum freedom, in these times of increasing risk for rural tropical wetland communities, to make the curriculum fit the local issues rather than vice versa. • Nurture critical analysis of the curriculum in local pedagogic discourse i.e., at the local contextualization level of the home, community and school.
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Effect of salinity on oxygen consumption and growth of juvenile white steenbras, litohognathus lithognathus
- Authors: Kandjou, Kaunahama
- Date: 2008
- Subjects: Lithognathus -- Growth , Salinity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5275 , http://hdl.handle.net/10962/d1005119 , Lithognathus -- Growth , Salinity
- Description: A stress-induced increase in metabolic rate of fish consumes energy within the metabolic scope of a fish that could otherwise be used for such functions as growth and reproduction. By estimating the degree of the metabolic response under given salinity levels and sudden changes thereof, it could be tested whether growth under given culture conditions could be predicted. Using intermittent respirometers, this study investigated the metabolic response of juvenile Lithognathus lithognathus following gradual acclimation to 5, 25 and 35‰ and, as a result of abrupt change from 35‰ to 5‰ or from 35‰ to 25‰ at 20˚C. The main aim of the study was to establish whether the magnitude of such responses could be used to predict growth of juvenile L. lithognathus under culture conditions. Hence, in addition to the respirometry study, two growth studies were conducted at 5, 10, 25 and 35‰ salinities. The baseline metabolic rates of juvenile L. lithognathus were also determined. Oxygen consumption measurements over 24-hours showed that most fish exhibited a diurnal peak in metabolic rates. The standard and active metabolic rates calculated from juvenile L. lithognathus with a diurnal peak in oxygen consumption were 0.06±0.001mgO₂g⁻¹h⁻¹ (mean±SEM, n = 5), and 0.11±0.01mg O₂g⁻¹h⁻¹, respectively. The standard and active metabolic rates of juvenile L lithognathus showing a nocturnal peak in metabolic activities were 0.04±0.001mgO₂g-1h-1 (n = 1), and 0.12±0.003 mg O₂g⁻¹ h⁻¹, respectively. Routine metabolic rate of these fish calculated over a 3-h measurement period was 0.09±0.005mgO₂g⁻¹h⁻¹ (n = 6). Juvenile L. lithognathus showed a relationship between metabolic rate (mo₂) and body weight (W) following the equation: mo₂ = 0.62 W⁻°·⁵³.
- Full Text:
- Authors: Kandjou, Kaunahama
- Date: 2008
- Subjects: Lithognathus -- Growth , Salinity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5275 , http://hdl.handle.net/10962/d1005119 , Lithognathus -- Growth , Salinity
- Description: A stress-induced increase in metabolic rate of fish consumes energy within the metabolic scope of a fish that could otherwise be used for such functions as growth and reproduction. By estimating the degree of the metabolic response under given salinity levels and sudden changes thereof, it could be tested whether growth under given culture conditions could be predicted. Using intermittent respirometers, this study investigated the metabolic response of juvenile Lithognathus lithognathus following gradual acclimation to 5, 25 and 35‰ and, as a result of abrupt change from 35‰ to 5‰ or from 35‰ to 25‰ at 20˚C. The main aim of the study was to establish whether the magnitude of such responses could be used to predict growth of juvenile L. lithognathus under culture conditions. Hence, in addition to the respirometry study, two growth studies were conducted at 5, 10, 25 and 35‰ salinities. The baseline metabolic rates of juvenile L. lithognathus were also determined. Oxygen consumption measurements over 24-hours showed that most fish exhibited a diurnal peak in metabolic rates. The standard and active metabolic rates calculated from juvenile L. lithognathus with a diurnal peak in oxygen consumption were 0.06±0.001mgO₂g⁻¹h⁻¹ (mean±SEM, n = 5), and 0.11±0.01mg O₂g⁻¹h⁻¹, respectively. The standard and active metabolic rates of juvenile L lithognathus showing a nocturnal peak in metabolic activities were 0.04±0.001mgO₂g-1h-1 (n = 1), and 0.12±0.003 mg O₂g⁻¹ h⁻¹, respectively. Routine metabolic rate of these fish calculated over a 3-h measurement period was 0.09±0.005mgO₂g⁻¹h⁻¹ (n = 6). Juvenile L. lithognathus showed a relationship between metabolic rate (mo₂) and body weight (W) following the equation: mo₂ = 0.62 W⁻°·⁵³.
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