The geology and geochemistry of the Palaeoproterozoic Makganyene diamictite
- Polteau, S, Moore, John M, Tsikos, Harilaos
- Authors: Polteau, S , Moore, John M , Tsikos, Harilaos
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6740 , http://hdl.handle.net/10962/d1007556
- Description: The Palaeoproterozoic Earth experienced a global glacial event at 2400 Ma that occurred during the transitional period from anoxic to aerobic conditions in the atmosphere and oceans. The Transvaal Supergroup in the Griqualand West Basin, South Africa, hosts glacial deposits and associated major iron and manganese deposits that are apparently related to these global changes. The focus of this study is to assess the stratigraphy and geochemistry of the glaciogenic Makganyene Formation, in order to constrain its palaeoenvironmental settings. The Makganyene Formation forms the base of the Postmasburg Group and has been regarded as resting on an erosive regional unconformity throughout the Northern Cape Province. Systematic regional field observations and regional mapping carried out during this study demonstrate that this stratigraphic relationship is not universal. The Makganyene Formation is, in fact, conformable with underlying formations of the Koegas Subgroup in the deep southern Prieska basin and rests on an unconformity only on the shallow Ghaap platform to the north-east. The Makganyene Formation displays lateral facies changes that reflect the palaeogeography of the study area, and the advance and retreat of ice sheets/shelves. Geochemical investigations of glacial strata of the Makganyene Formation demonstrate that underlying banded iron formations of the Transvaal Supergroup acted as the main clastic source for the diamictite detritus. Geographic variations in bulk composition of the diamictites correlate well with field observations, and show that sorting processes were controlled largely by the morphology of the palaeobasin. Carbon isotope results emphasize the transitional nature of the Makganyene Formation in terms of the environmental conditions that resulted in widespread global glaciation in the Palaeoproterozoic. On the basis of the above geological evidence, it is proposed that the Transvaal Supergroup in the Northern Cape Province represents a continuous depositional event that lasted approximately 250 Ma and hence provides a unique opportunity for assessing the transitional changes experienced by the Palaeoproterozoic Earth.
- Full Text:
- Date Issued: 2006
- Authors: Polteau, S , Moore, John M , Tsikos, Harilaos
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6740 , http://hdl.handle.net/10962/d1007556
- Description: The Palaeoproterozoic Earth experienced a global glacial event at 2400 Ma that occurred during the transitional period from anoxic to aerobic conditions in the atmosphere and oceans. The Transvaal Supergroup in the Griqualand West Basin, South Africa, hosts glacial deposits and associated major iron and manganese deposits that are apparently related to these global changes. The focus of this study is to assess the stratigraphy and geochemistry of the glaciogenic Makganyene Formation, in order to constrain its palaeoenvironmental settings. The Makganyene Formation forms the base of the Postmasburg Group and has been regarded as resting on an erosive regional unconformity throughout the Northern Cape Province. Systematic regional field observations and regional mapping carried out during this study demonstrate that this stratigraphic relationship is not universal. The Makganyene Formation is, in fact, conformable with underlying formations of the Koegas Subgroup in the deep southern Prieska basin and rests on an unconformity only on the shallow Ghaap platform to the north-east. The Makganyene Formation displays lateral facies changes that reflect the palaeogeography of the study area, and the advance and retreat of ice sheets/shelves. Geochemical investigations of glacial strata of the Makganyene Formation demonstrate that underlying banded iron formations of the Transvaal Supergroup acted as the main clastic source for the diamictite detritus. Geographic variations in bulk composition of the diamictites correlate well with field observations, and show that sorting processes were controlled largely by the morphology of the palaeobasin. Carbon isotope results emphasize the transitional nature of the Makganyene Formation in terms of the environmental conditions that resulted in widespread global glaciation in the Palaeoproterozoic. On the basis of the above geological evidence, it is proposed that the Transvaal Supergroup in the Northern Cape Province represents a continuous depositional event that lasted approximately 250 Ma and hence provides a unique opportunity for assessing the transitional changes experienced by the Palaeoproterozoic Earth.
- Full Text:
- Date Issued: 2006
The Post: 15 years of journalism with a conscience
- Authors: Banda, Fackson
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6327 , http://hdl.handle.net/10962/d1008467
- Description: This article celebrates the 15-year existence of the Post newspaper in Zambia, citing its unique niche as a purveyor of conscientious journalism. It justifies the Post's reportage in terms of what seems to be the paper's civic-journalistic mission.
- Full Text: false
- Date Issued: 2006
- Authors: Banda, Fackson
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6327 , http://hdl.handle.net/10962/d1008467
- Description: This article celebrates the 15-year existence of the Post newspaper in Zambia, citing its unique niche as a purveyor of conscientious journalism. It justifies the Post's reportage in terms of what seems to be the paper's civic-journalistic mission.
- Full Text: false
- Date Issued: 2006
Spatio-temporal patterns in maturation of the chokka squid (Loligo vulgaris reynaudii) off the coast of South Africa
- Olyott, L J H, Sauer, Warwick H H, Booth, Anthony J
- Authors: Olyott, L J H , Sauer, Warwick H H , Booth, Anthony J
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6763 , http://hdl.handle.net/10962/d1007930
- Description: Knowledge of the temporal and spatial characteristics of chokka squid (Loligo vulgaris reynaudii) biology in South African waters is limited, so the possibility of there being a geographically fragmented stock was examined by investigating the distribution of maturity patterns for the species, covering all known spawning areas and using both historical and recent data. Gonadosomatic indices (GSI) varied between year-round consistency and apparent seasonal peaks in both summer and winter; there was no clear spatial pattern. Monthly percentage maturity provided further evidence for two peak reproductive periods each year, although mature squid were present throughout. Sex ratios demonstrated great variability between different areas and life history stages. Male-biased sex ratios were only apparent on the inshore spawning grounds and ranged between 1.118:1 and 4.267:1. Size at sexual maturity was also seasonal, squid maturing smaller in winter/spring than in summer/autumn. Also, squid in the east matured smaller than squid in the west. Although the results from the present study do not provide conclusive evidence of distinct geographic populations, squid likely spawn over a significantly larger area of the Agulhas Bank than previously estimated, and squid on the west coast of South Africa may return to spawn on the western portion of the Agulhas Bank. It remains likely, however, that the east and west coast populations are a single stock and that migration of juveniles to the west coast and their subsequent return as sub-adults is an integral but non-essential and variable part of the life history.
- Full Text:
- Date Issued: 2006
- Authors: Olyott, L J H , Sauer, Warwick H H , Booth, Anthony J
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6763 , http://hdl.handle.net/10962/d1007930
- Description: Knowledge of the temporal and spatial characteristics of chokka squid (Loligo vulgaris reynaudii) biology in South African waters is limited, so the possibility of there being a geographically fragmented stock was examined by investigating the distribution of maturity patterns for the species, covering all known spawning areas and using both historical and recent data. Gonadosomatic indices (GSI) varied between year-round consistency and apparent seasonal peaks in both summer and winter; there was no clear spatial pattern. Monthly percentage maturity provided further evidence for two peak reproductive periods each year, although mature squid were present throughout. Sex ratios demonstrated great variability between different areas and life history stages. Male-biased sex ratios were only apparent on the inshore spawning grounds and ranged between 1.118:1 and 4.267:1. Size at sexual maturity was also seasonal, squid maturing smaller in winter/spring than in summer/autumn. Also, squid in the east matured smaller than squid in the west. Although the results from the present study do not provide conclusive evidence of distinct geographic populations, squid likely spawn over a significantly larger area of the Agulhas Bank than previously estimated, and squid on the west coast of South Africa may return to spawn on the western portion of the Agulhas Bank. It remains likely, however, that the east and west coast populations are a single stock and that migration of juveniles to the west coast and their subsequent return as sub-adults is an integral but non-essential and variable part of the life history.
- Full Text:
- Date Issued: 2006
Creating international support for the development of the news media in Africa
- Authors: Banda, Fackson
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6326 , http://hdl.handle.net/10962/d1008301
- Description: This article analyses the issues associated with providing support mechanisms for strengthening media institutions in Africa. It takes a historical look at the involvement of international actors in the evolution of African media, arguing that ideology plays a key role in the way international support is crafted for Africa's development, including media development.
- Full Text:
- Date Issued: 2006
- Authors: Banda, Fackson
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6326 , http://hdl.handle.net/10962/d1008301
- Description: This article analyses the issues associated with providing support mechanisms for strengthening media institutions in Africa. It takes a historical look at the involvement of international actors in the evolution of African media, arguing that ideology plays a key role in the way international support is crafted for Africa's development, including media development.
- Full Text:
- Date Issued: 2006
Electrocatalysis of oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione by adsorbed and electrodeposited cobalt tetra phenoxypyrrole and tetra ethoxythiophene substituted phthalocyanines
- Sehlotho, Nthapo, Nyokong, Tebello, Zagal, Jose H, Bedioui, Fethi
- Authors: Sehlotho, Nthapo , Nyokong, Tebello , Zagal, Jose H , Bedioui, Fethi
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6593 , http://hdl.handle.net/10962/d1004342
- Description: Catalytic activity of cobalt tetra ethoxythiophene and cobalt tetra phenoxypyrrole phthalocyanine complexes towards oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione is reported. It was found that the activity of the complexes depends on the substitution of the phthalocyanine ring, pH, film thickness and method of electrode modification. The high electrocatalytic activity obtained with adsorbed complexes in alkaline medium clearly demonstrates the necessity of modifying bare carbon electrodes to endow them with the desired behaviour.
- Full Text:
- Date Issued: 2006
- Authors: Sehlotho, Nthapo , Nyokong, Tebello , Zagal, Jose H , Bedioui, Fethi
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6593 , http://hdl.handle.net/10962/d1004342
- Description: Catalytic activity of cobalt tetra ethoxythiophene and cobalt tetra phenoxypyrrole phthalocyanine complexes towards oxidation of 2-mercaptoethanol, L-cysteine and reduced glutathione is reported. It was found that the activity of the complexes depends on the substitution of the phthalocyanine ring, pH, film thickness and method of electrode modification. The high electrocatalytic activity obtained with adsorbed complexes in alkaline medium clearly demonstrates the necessity of modifying bare carbon electrodes to endow them with the desired behaviour.
- Full Text:
- Date Issued: 2006
The Bellman's tale - Part 2
- Authors: Berning, J M
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6990 , http://hdl.handle.net/10962/d1012413
- Description: Michael Berning was a member of the Rhodes University Library staff from 1965 until his retirement in 1997. He was Tower Captain of the Grahamstown Cathedral during the 1980s.
- Full Text:
- Date Issued: 2006
- Authors: Berning, J M
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6990 , http://hdl.handle.net/10962/d1012413
- Description: Michael Berning was a member of the Rhodes University Library staff from 1965 until his retirement in 1997. He was Tower Captain of the Grahamstown Cathedral during the 1980s.
- Full Text:
- Date Issued: 2006
Generic substitution: the use of medicinal products containing different salts and implications for safety and efficacy
- Verbeeck, R K, Kanfer, Isadore, Walker, Roderick B
- Authors: Verbeeck, R K , Kanfer, Isadore , Walker, Roderick B
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6445 , http://hdl.handle.net/10962/d1006632
- Description: In their quest to gain early entry of new generic products into the market prior to patent expiration, one of the strategies pursued by generic drug product manufacturers is to incorporate different salts of an approved active pharmaceutical ingredient (API) in a brand company's marketed dosage form and subject such dosage forms to bioequivalence assessment. These initiatives present challenges to regulatory authorities where the decision to approve bioequivalent products containing such pharmaceutical alternatives must be considered in the light of safety and efficacy, and more particularly, with respect to their substitutability. This article describes the various issues and contentions associated with the concept of pharmaceutical alternatives, specifically with respect to the uses of different salts and the implications for safety, efficacy and generic substitution.
- Full Text:
- Date Issued: 2006
- Authors: Verbeeck, R K , Kanfer, Isadore , Walker, Roderick B
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6445 , http://hdl.handle.net/10962/d1006632
- Description: In their quest to gain early entry of new generic products into the market prior to patent expiration, one of the strategies pursued by generic drug product manufacturers is to incorporate different salts of an approved active pharmaceutical ingredient (API) in a brand company's marketed dosage form and subject such dosage forms to bioequivalence assessment. These initiatives present challenges to regulatory authorities where the decision to approve bioequivalent products containing such pharmaceutical alternatives must be considered in the light of safety and efficacy, and more particularly, with respect to their substitutability. This article describes the various issues and contentions associated with the concept of pharmaceutical alternatives, specifically with respect to the uses of different salts and the implications for safety, efficacy and generic substitution.
- Full Text:
- Date Issued: 2006
Synthesis of triprenylated toluquinone and toluhydroquinone metabolites from a marine-derived Penicillium fungus
- Scheepers, Brent A, Klein, Rosalyn, Davies-Coleman, Michael T
- Authors: Scheepers, Brent A , Klein, Rosalyn , Davies-Coleman, Michael T
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6592 , http://hdl.handle.net/10962/d1004341
- Description: Two triprenylated toluquinone and toluhydroquinone marine fungal metabolites, 5-methyl-2-[(2′E,6′E)-3′,7′,11′-trimethyl-2′,6′,10′-dodecatrienyl]-2,5-cyclohexadiene-1,4-dione and 5-methyl-2-[(2′E,6′E)-3,7,11-trimethyl-2′,6′,10′-dodecatrienyl]-1,4-benzenediol, were synthesized in four and five steps, respectively, from 2-methyl-1,4-benzoquinone. The synthesis extends the applicability of the oxidative ether cleavage of hydroquinone dimethyl ethers with argentic oxide under acidic conditions to include the oxidative demethylation of polyprenylated-1,4-dimethoxy-toluhydroquinones with a quantitative survival of the oxidation- and acid-sensitive polyprenyl side chain. Graphical abstract: Marine fungal metabolites 1 and 2 were synthesized from 2-methyl-1,4-benzoquinone in four and five steps, respectively. [For graphic image see full-text version]
- Full Text:
- Date Issued: 2006
- Authors: Scheepers, Brent A , Klein, Rosalyn , Davies-Coleman, Michael T
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6592 , http://hdl.handle.net/10962/d1004341
- Description: Two triprenylated toluquinone and toluhydroquinone marine fungal metabolites, 5-methyl-2-[(2′E,6′E)-3′,7′,11′-trimethyl-2′,6′,10′-dodecatrienyl]-2,5-cyclohexadiene-1,4-dione and 5-methyl-2-[(2′E,6′E)-3,7,11-trimethyl-2′,6′,10′-dodecatrienyl]-1,4-benzenediol, were synthesized in four and five steps, respectively, from 2-methyl-1,4-benzoquinone. The synthesis extends the applicability of the oxidative ether cleavage of hydroquinone dimethyl ethers with argentic oxide under acidic conditions to include the oxidative demethylation of polyprenylated-1,4-dimethoxy-toluhydroquinones with a quantitative survival of the oxidation- and acid-sensitive polyprenyl side chain. Graphical abstract: Marine fungal metabolites 1 and 2 were synthesized from 2-methyl-1,4-benzoquinone in four and five steps, respectively. [For graphic image see full-text version]
- Full Text:
- Date Issued: 2006
Novel amperometric glucose biosensor based on an ether-linked cobalt(II) phthalocyaninecobalt(II) tetraphenylporphyrin pentamer as a redox mediator
- Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6583 , http://hdl.handle.net/10962/d1004148
- Description: The development of cobalt(II) phthalocyanine–cobalt(II) tetra(5-phenoxy-10,15,20-triphenylporphyrin), (CoPc–(CoTPP)[subscript 4]) pentamer as a novel redox mediator for amperometric enzyme electrode sensitive to glucose is described. A glassy carbon electrode (GCE) was first modified with the pentamer, then followed by the immobilization onto the GCE–CoPc–(CoTPP)[subscript 4] with glucose oxidase (GOx) through cross-linking with glutaraldehyde in the presence of bovine serum albumin (BSA) and Nafion® cation-exchange polymer. The proposed biosensor displayed good amperometric respose charateristics to glucose in pH 7.0 PBS solution; such as low overpotentials (+400 mV versus Ag|AgCl), very fast amperometric response time (~5 s), linear concentration range extended up to 11 mM, with 10 μM detection limit. The biosensor exhibited electrochemical Michaelis–Menten kinetics and showed an average apparent Michaelis–Menten constant (K′M) of 14.91 ± 0.46 mM over a storage period of 2 weeks.
- Full Text:
- Date Issued: 2006
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6583 , http://hdl.handle.net/10962/d1004148
- Description: The development of cobalt(II) phthalocyanine–cobalt(II) tetra(5-phenoxy-10,15,20-triphenylporphyrin), (CoPc–(CoTPP)[subscript 4]) pentamer as a novel redox mediator for amperometric enzyme electrode sensitive to glucose is described. A glassy carbon electrode (GCE) was first modified with the pentamer, then followed by the immobilization onto the GCE–CoPc–(CoTPP)[subscript 4] with glucose oxidase (GOx) through cross-linking with glutaraldehyde in the presence of bovine serum albumin (BSA) and Nafion® cation-exchange polymer. The proposed biosensor displayed good amperometric respose charateristics to glucose in pH 7.0 PBS solution; such as low overpotentials (+400 mV versus Ag|AgCl), very fast amperometric response time (~5 s), linear concentration range extended up to 11 mM, with 10 μM detection limit. The biosensor exhibited electrochemical Michaelis–Menten kinetics and showed an average apparent Michaelis–Menten constant (K′M) of 14.91 ± 0.46 mM over a storage period of 2 weeks.
- Full Text:
- Date Issued: 2006
Ethnicity, not class? The 1929 Bulawayo faction fights reconsidered
- Authors: Msindo, Enocent
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6150 , http://hdl.handle.net/10962/d1006816 , http://dx.doi.org/10.1080/03057070600829419
- Description: From Christmas Eve of 1929 to the end of that year, Bulawayo was an ungovernable city marred by fights between Shona, on the one hand (perceived as a 'common enemy'), and forces that were predominantly Ndebele and groups sympathetic to them. A brilliant attempt to explain these clashes a generation ago, nevertheless falls short. This article seeks to revise the popular interpretation of this violence and re-contextualise it historically. A longer timeframe would give us an alternative view of the conflict. It also vindicates the ethnic interpretation of the violence that Phimister and van Onselen, concentrating on the then popular Marxist 'class struggle' paradigm, either minimised or failed to assess thoroughly.
- Full Text:
- Date Issued: 2006
- Authors: Msindo, Enocent
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6150 , http://hdl.handle.net/10962/d1006816 , http://dx.doi.org/10.1080/03057070600829419
- Description: From Christmas Eve of 1929 to the end of that year, Bulawayo was an ungovernable city marred by fights between Shona, on the one hand (perceived as a 'common enemy'), and forces that were predominantly Ndebele and groups sympathetic to them. A brilliant attempt to explain these clashes a generation ago, nevertheless falls short. This article seeks to revise the popular interpretation of this violence and re-contextualise it historically. A longer timeframe would give us an alternative view of the conflict. It also vindicates the ethnic interpretation of the violence that Phimister and van Onselen, concentrating on the then popular Marxist 'class struggle' paradigm, either minimised or failed to assess thoroughly.
- Full Text:
- Date Issued: 2006
A Geographic Information System for the African Coelacanth Ecosystem Programme
- Authors: Scott, Lucy E P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7129 , http://hdl.handle.net/10962/d1010639
- Description: The African Coelacanth Ecosystem Programme (ACEP) Geographic Information System (GIS) has been developed to integrate, analyse and map all spatial data generated within the ACEP programme. A GIS is a multidisciplinary tool, and within ACEP the GIS has been used to integrate information from marine biology studies, oceanographic surveys, geophysical exploration as well as the observations made and footage taken from a research submersible. The core data in the GIS are based on deep marine ecosystems and the programme’s flagship species, Latimeria chalumnae (the coelacanth). Over and above the utility of the GIS as a tool for science through its considerable information storage, analysis and display capabilities, the ACEP GIS has been used for interactive environmental education purposes and to generate public awareness of the programme at various meetings, training events and conferences.
- Full Text:
- Date Issued: 2006
- Authors: Scott, Lucy E P
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7129 , http://hdl.handle.net/10962/d1010639
- Description: The African Coelacanth Ecosystem Programme (ACEP) Geographic Information System (GIS) has been developed to integrate, analyse and map all spatial data generated within the ACEP programme. A GIS is a multidisciplinary tool, and within ACEP the GIS has been used to integrate information from marine biology studies, oceanographic surveys, geophysical exploration as well as the observations made and footage taken from a research submersible. The core data in the GIS are based on deep marine ecosystems and the programme’s flagship species, Latimeria chalumnae (the coelacanth). Over and above the utility of the GIS as a tool for science through its considerable information storage, analysis and display capabilities, the ACEP GIS has been used for interactive environmental education purposes and to generate public awareness of the programme at various meetings, training events and conferences.
- Full Text:
- Date Issued: 2006
Book review: Derek Barker: English Academic Literary Discourse in South Africa 1958-2004: A Review of 11 Academic Journals
- Authors: Wright, Laurence
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7044 , http://hdl.handle.net/10962/d1007386
- Description: Barker’s book concerns the evolution and publishing trajectories of South African journals devoted to English literary studies between the years 1958 (when the first such journal, English Studies in Africa, came into being) and 2004, the end-date of the survey. In other words, his work coincides with the period in South African history when apartheid’s protagonists were pushing for total political and social ascendancy through to the nation’s emergence into the arena of democratic possibility.
- Full Text:
- Date Issued: 2006
- Authors: Wright, Laurence
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7044 , http://hdl.handle.net/10962/d1007386
- Description: Barker’s book concerns the evolution and publishing trajectories of South African journals devoted to English literary studies between the years 1958 (when the first such journal, English Studies in Africa, came into being) and 2004, the end-date of the survey. In other words, his work coincides with the period in South African history when apartheid’s protagonists were pushing for total political and social ascendancy through to the nation’s emergence into the arena of democratic possibility.
- Full Text:
- Date Issued: 2006
The management of risk: adolescent sexual and reproductive health in South Africa
- Authors: Macleod, Catriona I
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6302 , http://hdl.handle.net/10962/d1015958
- Description: Scientific discourse allows for the calculation of negative outcomes attendant on conception and birth during adolescence, thereby producing a discourse of risk. The management of risk allows for the deployment of governmental apparatuses of security. Security, as outlined by Foucault, is a specific principle of political method and practice aimed at defending and securing a national population. In this paper I analyse how techniques of security are deployed in the interactions between health service providers and young women seeking contraceptive and reproductive assistance at a regional hospital in South Africa, and how racialised and gendered politics are strategically deployed within these techniques. Security combines with various governmental techniques to produce its effects. The techniques used in this instance include pastoral care, liberal humanism, the incitement to governmental self-formation, and, in the last instance, sovereign power.
- Full Text:
- Date Issued: 2006
- Authors: Macleod, Catriona I
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6302 , http://hdl.handle.net/10962/d1015958
- Description: Scientific discourse allows for the calculation of negative outcomes attendant on conception and birth during adolescence, thereby producing a discourse of risk. The management of risk allows for the deployment of governmental apparatuses of security. Security, as outlined by Foucault, is a specific principle of political method and practice aimed at defending and securing a national population. In this paper I analyse how techniques of security are deployed in the interactions between health service providers and young women seeking contraceptive and reproductive assistance at a regional hospital in South Africa, and how racialised and gendered politics are strategically deployed within these techniques. Security combines with various governmental techniques to produce its effects. The techniques used in this instance include pastoral care, liberal humanism, the incitement to governmental self-formation, and, in the last instance, sovereign power.
- Full Text:
- Date Issued: 2006
Structure and distribution of the slope fish community in the vicinity of the sub-Antarctic Prince Edward Archipelago
- Pakhomov, E A, Bushula, T, Kaehler, Sven, Watkins, B P, Leslie, R W
- Authors: Pakhomov, E A , Bushula, T , Kaehler, Sven , Watkins, B P , Leslie, R W
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6958 , http://hdl.handle.net/10962/d1012000
- Description: Demersal fish community structure, distribution and trophic relationships on the slope (depth range 200–1500 m) of the sub-Antarctic Prince Edward Islands and surrounding sea rises were investigated during a pilot survey conducted in April 2001 onboard fishing vessel MV Iris. A total of 56 fish taxa were collected during the survey, of which 44 were identified to the species level, seven to the genus level and five to the family level. Among the identified taxa, 36 constituted new records for the area investigated. Total catch per unit effort (cpue) during the survey ranged from 1•1 to 241•2 individuals h 1. Both average fish diversity and total cpue positively correlated with trawling depth. Overall, mean sampling depth and near-bottom temperature explained 56% of total fish cpue. Hierarchal cluster analysis identified three distinct fish assemblages with pronounced dominant species. Major shifts in fish community composition occurred at 500–600 m and 800–900 m depth strata and could probably be a result of physical and biological vertical zonation. Analysis of the diet of selected fish species showed that they were generalist feeders, consuming predominantly pelagic, including epipelagic, meso- and benthopelagic, prey. Diets of six species and nitrogen stable isotope signatures of 22 species revealed that with a few exceptions most fishes occupied the fourth trophic level and were tertiary consumers. Wide variability in carbon isotopic signatures is discussed with respect to alternative, e.g. possible importance of high Antarctic and chemoautotrophic v. photoautotrophic sub-Antarctic primary production, organic matter sources at the base of deep-sea food webs.
- Full Text:
- Date Issued: 2006
- Authors: Pakhomov, E A , Bushula, T , Kaehler, Sven , Watkins, B P , Leslie, R W
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6958 , http://hdl.handle.net/10962/d1012000
- Description: Demersal fish community structure, distribution and trophic relationships on the slope (depth range 200–1500 m) of the sub-Antarctic Prince Edward Islands and surrounding sea rises were investigated during a pilot survey conducted in April 2001 onboard fishing vessel MV Iris. A total of 56 fish taxa were collected during the survey, of which 44 were identified to the species level, seven to the genus level and five to the family level. Among the identified taxa, 36 constituted new records for the area investigated. Total catch per unit effort (cpue) during the survey ranged from 1•1 to 241•2 individuals h 1. Both average fish diversity and total cpue positively correlated with trawling depth. Overall, mean sampling depth and near-bottom temperature explained 56% of total fish cpue. Hierarchal cluster analysis identified three distinct fish assemblages with pronounced dominant species. Major shifts in fish community composition occurred at 500–600 m and 800–900 m depth strata and could probably be a result of physical and biological vertical zonation. Analysis of the diet of selected fish species showed that they were generalist feeders, consuming predominantly pelagic, including epipelagic, meso- and benthopelagic, prey. Diets of six species and nitrogen stable isotope signatures of 22 species revealed that with a few exceptions most fishes occupied the fourth trophic level and were tertiary consumers. Wide variability in carbon isotopic signatures is discussed with respect to alternative, e.g. possible importance of high Antarctic and chemoautotrophic v. photoautotrophic sub-Antarctic primary production, organic matter sources at the base of deep-sea food webs.
- Full Text:
- Date Issued: 2006
Electrocatalysis of asulam on cobalt phthalocyanine modified multi-walled carbon nanotubes immobilized on a basal plane pyrolytic graphite electrode
- Siswana, Msimelelo P, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6595 , http://hdl.handle.net/10962/d1004344
- Description: This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (~6 times) and the shift in the oxidation potential to lower values (by ~120 mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10 M phosphate buffer (pH 7.0) at a fixed potential of 0.65 V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20 μM, a sensitivity of 241 × 10[superscript −3] μA/μM, a detection limit of 1.15 μM asulam (using the Y[subscript B] + 3σ criterion) and a response time of ~2 s.
- Full Text:
- Date Issued: 2006
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6595 , http://hdl.handle.net/10962/d1004344
- Description: This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (~6 times) and the shift in the oxidation potential to lower values (by ~120 mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10 M phosphate buffer (pH 7.0) at a fixed potential of 0.65 V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20 μM, a sensitivity of 241 × 10[superscript −3] μA/μM, a detection limit of 1.15 μM asulam (using the Y[subscript B] + 3σ criterion) and a response time of ~2 s.
- Full Text:
- Date Issued: 2006
Fishes of the deep demersal habitat at Ngazidja (Grand Comoro) Island, Western Indian Ocean
- Heemstra, P C, Hissmann, K, Fricke, H
- Authors: Heemstra, P C , Hissmann, K , Fricke, H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7128 , http://hdl.handle.net/10962/d1010638
- Description: Underwater observations of the coelacanth, Latimeria chalumnae Smith, 1939, from a research submersible provided opportunities to study the deep demersal fish fauna at the Comoro Islands. The demersal habitat in depths of 150–400 m at the volcanic island of Ngazidja is low in fish diversity and biomass, compared with the shallow-water coral reef habitat of Ngazidja or the deep demersal habitats of other localities in the Indo-Pacific region. The resident deep demersal fish fauna at Ngazidja is dominated by the coelacanth, an ancient predator that is specially adapted for this low-energy environment. Other large fish predators are scarce in this environment, because of the heavy fishing pressure from local fishermen. Eighty-nine fish taxa (including 65 recognizable species) were recorded from videotapes, photographs, visual observations, fishermen’s catches and ancillary attempts to sample the fish fauna with baited fish traps, gill nets, and hook and line. Although no coelacanth feeding events were seen, seven fish species are known from coelacanth stomach contents, and 64 other fish species in this habitat are considered potential prey of this dominant predator.
- Full Text:
- Date Issued: 2006
- Authors: Heemstra, P C , Hissmann, K , Fricke, H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7128 , http://hdl.handle.net/10962/d1010638
- Description: Underwater observations of the coelacanth, Latimeria chalumnae Smith, 1939, from a research submersible provided opportunities to study the deep demersal fish fauna at the Comoro Islands. The demersal habitat in depths of 150–400 m at the volcanic island of Ngazidja is low in fish diversity and biomass, compared with the shallow-water coral reef habitat of Ngazidja or the deep demersal habitats of other localities in the Indo-Pacific region. The resident deep demersal fish fauna at Ngazidja is dominated by the coelacanth, an ancient predator that is specially adapted for this low-energy environment. Other large fish predators are scarce in this environment, because of the heavy fishing pressure from local fishermen. Eighty-nine fish taxa (including 65 recognizable species) were recorded from videotapes, photographs, visual observations, fishermen’s catches and ancillary attempts to sample the fish fauna with baited fish traps, gill nets, and hook and line. Although no coelacanth feeding events were seen, seven fish species are known from coelacanth stomach contents, and 64 other fish species in this habitat are considered potential prey of this dominant predator.
- Full Text:
- Date Issued: 2006
Non-steroidal anti-inflammatory agents, tolmetin and sulindac, inhibit liver tryptophan 2,3-dioxygenase activity and alter brain neurotransmitter levels
- Dairam, A, Antunes, Edith M, Saravanan, K S, Daya, Santylal
- Authors: Dairam, A , Antunes, Edith M , Saravanan, K S , Daya, Santylal
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6358 , http://hdl.handle.net/10962/d1006050 , http://dx.doi.org/10.1016/j.lfs.2006.07.028
- Description: Hepatic tryptophan 2,3-dioxygenase (TDO) is one of the rate-limiting enzymes in tryptophan catabolism and plays an important role in regulating the physiological flux of tryptophan into relevant metabolic pathways. In this study, we determined the effect of the non-steroidal anti-inflammatory agents, tolmetin and sulindac, on rat liver TDO activity and the subsequent changes in the hippocampal and striatal neurotransmitter levels. The amount of melatonin produced by the pineal gland was also measured using high performance liquid chromatography (HPLC). Treatment of rats with tolmetin or sulindac (5 mg/kg/bd for 5 days) significantly inhibited liver TDO activity. The results show that whilst tolmetin and sulindac increase serotonin levels in the hippocampus, these agents also significantly reduce dopamine levels in the striatum. Tolmetin, but not sulindac, increased the amount of melatonin produced by the pineal gland. The results of this study suggest that whilst tolmetin and sulindac may be beneficial for patients suffering from depression, these agents also have the potential to induce adverse effects in patients suffering with neurological disorders such as Parkinson's disease.
- Full Text:
- Date Issued: 2006
- Authors: Dairam, A , Antunes, Edith M , Saravanan, K S , Daya, Santylal
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6358 , http://hdl.handle.net/10962/d1006050 , http://dx.doi.org/10.1016/j.lfs.2006.07.028
- Description: Hepatic tryptophan 2,3-dioxygenase (TDO) is one of the rate-limiting enzymes in tryptophan catabolism and plays an important role in regulating the physiological flux of tryptophan into relevant metabolic pathways. In this study, we determined the effect of the non-steroidal anti-inflammatory agents, tolmetin and sulindac, on rat liver TDO activity and the subsequent changes in the hippocampal and striatal neurotransmitter levels. The amount of melatonin produced by the pineal gland was also measured using high performance liquid chromatography (HPLC). Treatment of rats with tolmetin or sulindac (5 mg/kg/bd for 5 days) significantly inhibited liver TDO activity. The results show that whilst tolmetin and sulindac increase serotonin levels in the hippocampus, these agents also significantly reduce dopamine levels in the striatum. Tolmetin, but not sulindac, increased the amount of melatonin produced by the pineal gland. The results of this study suggest that whilst tolmetin and sulindac may be beneficial for patients suffering from depression, these agents also have the potential to induce adverse effects in patients suffering with neurological disorders such as Parkinson's disease.
- Full Text:
- Date Issued: 2006
Evaluation of kinetic parameters of traps in thermoluminescence phosphors
- Ogundare, F O, Balogun, F A, Hussain, L
- Authors: Ogundare, F O , Balogun, F A , Hussain, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6798 , http://hdl.handle.net/10962/d1003924 , http://dx.doi.org/10.1016/j.radmeas.2006.06.014
- Description: A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria.
- Full Text:
- Date Issued: 2006
- Authors: Ogundare, F O , Balogun, F A , Hussain, L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6798 , http://hdl.handle.net/10962/d1003924 , http://dx.doi.org/10.1016/j.radmeas.2006.06.014
- Description: A method for evaluating trap depth E, order of kinetics b and frequency factor s from a thermoluminescence (TL) glow peak has been developed. The method is based on using intensities and temperatures at any three points on the glow peak. Unlike similar techniques that provide no expression for frequency factor, the present formulation provides such an expression. The expression does not require knowledge of the temperature at which maximum intensity occurs, a parameter not usually known accurately from experimental glow peak data. For the method, it is found that use of points in the ascending part of the glow peak where the intensities are less than 10% maximum intensity gives parameter values closest to the true ones. Possible reasons for getting less accurate results when points are taken beyond this region are discussed. Values of the activation energy calculated using the present technique were always close to the true value. However, the frequency factor only approaches the true value as the dose given to the sample approaches saturation. When the three data points are selected in the initial-rise region, the equation for evaluating E in the method described in this paper becomes a two-point version of the initial-rise method. The advantage of the present technique over the initial-rise method is that it also gives b and hence s. The method is used to analyse the TL glow curve of a gamma-irradiated sample from Ijero-Ekiti, Nigeria.
- Full Text:
- Date Issued: 2006
A generic database and spatial interface for the application of hydrological and water resource models
- Hughes, Denis A, Forsyth, D A
- Authors: Hughes, Denis A , Forsyth, D A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7080 , http://hdl.handle.net/10962/d1012333
- Description: The paper discusses a software package that has been designed to enhance the efficiency of applying a range of hydrological and water resource simulation models. The SPATSIM (SPatial and Time Series Information Modeling) system has been developed in Delphi using MapObjects and incorporates a spatial data interface for access to the different types of information commonly associated with water resource analyses. All of the information is stored within database tables (Paradox by default) with generic structures. The structure and components of the system are briefly described and some example applications provided. The discussion identifies some of the criticisms that have been leveled at the software, the approach of the developers to user support and some possible future developments. The conclusions suggest that the development can be considered successful in that it has substantially improved the efficiency of the Institute for Water Research to undertake one of its core functions of hydrological model development and application.
- Full Text:
- Date Issued: 2006
- Authors: Hughes, Denis A , Forsyth, D A
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7080 , http://hdl.handle.net/10962/d1012333
- Description: The paper discusses a software package that has been designed to enhance the efficiency of applying a range of hydrological and water resource simulation models. The SPATSIM (SPatial and Time Series Information Modeling) system has been developed in Delphi using MapObjects and incorporates a spatial data interface for access to the different types of information commonly associated with water resource analyses. All of the information is stored within database tables (Paradox by default) with generic structures. The structure and components of the system are briefly described and some example applications provided. The discussion identifies some of the criticisms that have been leveled at the software, the approach of the developers to user support and some possible future developments. The conclusions suggest that the development can be considered successful in that it has substantially improved the efficiency of the Institute for Water Research to undertake one of its core functions of hydrological model development and application.
- Full Text:
- Date Issued: 2006
Improving the bioremediation of phenolic wastewaters by Trametes versicolor
- Ryan, D, Leukes, W, Burton, Stephanie G
- Authors: Ryan, D , Leukes, W , Burton, Stephanie G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6467 , http://hdl.handle.net/10962/d1005796 , http://dx.doi.org/10.1016/j.biortech.2006.02.001
- Description: The successful bioremediation of a phenolic wastewater by Trametes versicolor was found to be dependent on a range of factors including: fungal growth, culture age and activity and enzyme (laccase) production. These aspects were enhanced by the optimisation of the growth medium used and time of addition of the pollutant to the fungal cultures. Different media containing ‘high’ (20 g/L), ‘low’ (2 g/L) and ‘sufficient’ (10 g/L) concentrations of carbon and nitrogen sources were investigated. The medium containing both glucose and peptone at 10 g/L resulted in the highest Growth Related Productivity (the product of specific yield and μ) of laccase (1.46 Units of laccase activity)/gram biomass/day and was used in all further experiments. The use of the guaiacol as an inducer further increased laccase activity 780% without inhibiting growth; similarly the phenolic effluent studied boosted activity almost 5 times. The timing of the addition of the phenolic effluent was found to have important consequences in its removal and at least 8 days of prior growth was required. Under these conditions, 0.125 g phenol/g biomass and 0.231 g o-cresol/g biomass were removed from solution per day.
- Full Text:
- Date Issued: 2006
- Authors: Ryan, D , Leukes, W , Burton, Stephanie G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6467 , http://hdl.handle.net/10962/d1005796 , http://dx.doi.org/10.1016/j.biortech.2006.02.001
- Description: The successful bioremediation of a phenolic wastewater by Trametes versicolor was found to be dependent on a range of factors including: fungal growth, culture age and activity and enzyme (laccase) production. These aspects were enhanced by the optimisation of the growth medium used and time of addition of the pollutant to the fungal cultures. Different media containing ‘high’ (20 g/L), ‘low’ (2 g/L) and ‘sufficient’ (10 g/L) concentrations of carbon and nitrogen sources were investigated. The medium containing both glucose and peptone at 10 g/L resulted in the highest Growth Related Productivity (the product of specific yield and μ) of laccase (1.46 Units of laccase activity)/gram biomass/day and was used in all further experiments. The use of the guaiacol as an inducer further increased laccase activity 780% without inhibiting growth; similarly the phenolic effluent studied boosted activity almost 5 times. The timing of the addition of the phenolic effluent was found to have important consequences in its removal and at least 8 days of prior growth was required. Under these conditions, 0.125 g phenol/g biomass and 0.231 g o-cresol/g biomass were removed from solution per day.
- Full Text:
- Date Issued: 2006