Metallophthalocyanine catalysed electroreduction of nitrate and nitrite ions in alkaline media
- Chebotareva, Natalia, Nyokong, Tebello
- Authors: Chebotareva, Natalia , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293301 , vital:57073 , xlink:href="https://doi.org/10.1023/A:1018466021838"
- Description: Copper, cadmium, lead and bismuth (> 5 μg ml−1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4-t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed a different behaviour from the other three metals in that the highest current response was observed with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper.
- Full Text: false
- Date Issued: 1997
- Authors: Chebotareva, Natalia , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293301 , vital:57073 , xlink:href="https://doi.org/10.1023/A:1018466021838"
- Description: Copper, cadmium, lead and bismuth (> 5 μg ml−1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4-t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed a different behaviour from the other three metals in that the highest current response was observed with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper.
- Full Text: false
- Date Issued: 1997
Multivariate analysis of honeybee populations, Apis mellifera Linnaeus (Hymenoptera: Apidae), from western central Africa morphometries and pheromones
- Radloff, Sarah E, Hepburn, H Randall
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451963 , vital:75091 , https://hdl.handle.net/10520/AJA10213589_298
- Description: Morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to characterize their populations along a transect through three ecological-climatological zones in Cameroon. There are three distinct homogeneous populations and two zones of hybridization. These bees are designated as A. m. adansollii Latreille whose area of distribution is intruded by an A. m. montieola-like montane group of bees and a third group, A. m. jemertitica Ruttner. The delineation of the hybrid zones is supported by intercolonial variance spectra and these significant asymmetries are coincident with transitions between the ecological-climatological zones.
- Full Text:
- Date Issued: 1997
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451963 , vital:75091 , https://hdl.handle.net/10520/AJA10213589_298
- Description: Morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to characterize their populations along a transect through three ecological-climatological zones in Cameroon. There are three distinct homogeneous populations and two zones of hybridization. These bees are designated as A. m. adansollii Latreille whose area of distribution is intruded by an A. m. montieola-like montane group of bees and a third group, A. m. jemertitica Ruttner. The delineation of the hybrid zones is supported by intercolonial variance spectra and these significant asymmetries are coincident with transitions between the ecological-climatological zones.
- Full Text:
- Date Issued: 1997
Multivariate analysis of honeybees, Apis mellifera Linnaeus (Hymenoptera: Apidae), of the Horn of Africa
- Radloff, Sarah E, Hepburn, H Randall
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451987 , vital:75093 , https://hdl.handle.net/10520/AJA10213589_154
- Description: Morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to delineate the honeybee populations of the Horn of Africa. Four discrete and statistically homogeneous populations were identified: A. m. jemenitica Ruttner, A. m. bandasii Mogga, A. m. sudanensis Rashad in Ethiopia and an unclassified group in southwestern Somalia. Areas of high intercolonial variance are interpreted as zones of hybridization between the populations.
- Full Text:
- Date Issued: 1997
- Authors: Radloff, Sarah E , Hepburn, H Randall
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451987 , vital:75093 , https://hdl.handle.net/10520/AJA10213589_154
- Description: Morphometric characters and sting pheromones of worker honeybees, Apis mellifera Linnaeus, were analysed by multivariate methods to delineate the honeybee populations of the Horn of Africa. Four discrete and statistically homogeneous populations were identified: A. m. jemenitica Ruttner, A. m. bandasii Mogga, A. m. sudanensis Rashad in Ethiopia and an unclassified group in southwestern Somalia. Areas of high intercolonial variance are interpreted as zones of hybridization between the populations.
- Full Text:
- Date Issued: 1997
Novas, eclipses and the English stage, 1598-1608
- Authors: Butler, Guy F
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457738 , vital:75675 , https://hdl.handle.net/10520/AJA1011582X_6
- Description: In the sixteenth and early-seventeenth centuries very few kings, queens or councillors or, indeed, ordinary folk, made any important decisions without consulting their horoscopes. There is no reason to believe that Shakespeare was more sceptical about astrological prediction than his tough-minded Queen; but, even if he were sceptical, he could and did exploit his audience's susceptibility for dramatic ends. A reference to the stars could lift his action from the earthly to the cosmic. Astrological phenomena signalled the involvement of the Heavens with human affairs. In a sense, he and his fellow-dramatists had no option but to exploit the Heavens, because the canopy over half of the Elizabethan stage was referred to as 'the heavens.' It was adorned with paintings of the planets and the signs of the Zodiac. The heavens were built into his theatre, Let us start with eclipses of the sun and moon.
- Full Text:
- Date Issued: 1997
- Authors: Butler, Guy F
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457738 , vital:75675 , https://hdl.handle.net/10520/AJA1011582X_6
- Description: In the sixteenth and early-seventeenth centuries very few kings, queens or councillors or, indeed, ordinary folk, made any important decisions without consulting their horoscopes. There is no reason to believe that Shakespeare was more sceptical about astrological prediction than his tough-minded Queen; but, even if he were sceptical, he could and did exploit his audience's susceptibility for dramatic ends. A reference to the stars could lift his action from the earthly to the cosmic. Astrological phenomena signalled the involvement of the Heavens with human affairs. In a sense, he and his fellow-dramatists had no option but to exploit the Heavens, because the canopy over half of the Elizabethan stage was referred to as 'the heavens.' It was adorned with paintings of the planets and the signs of the Zodiac. The heavens were built into his theatre, Let us start with eclipses of the sun and moon.
- Full Text:
- Date Issued: 1997
Photosensitization reactions of neodymium, dysprosium and lutetium diphthalocyanine
- Nensala, Ngudiankama, Nyokong, Tebello
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:57084 , xlink:href="https://doi.org/10.1016/S0277-5387(97)00045-4"
- Description: Photolysis, using a visible radiation, of diphthalocyanine complexes of NdIII, DyIII and LuIII ([Pc(−2)NdIIIPc(−2)]−, [Pc(−2)DyIIIPc(−2)]− and [Pc(−2)LuIIIPc(−2)]−, respectively) in the presence of pentachlorophenol (PCP) or SO2 results in the one-electron oxidation of the diphthalocyanine species to Pc(−1)NdIIIPc(−2), Pc(−1)DyIIIPc(−2) and Pc(−2)LuIIIPc(−2), respectively. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are of the order 10−4.
- Full Text:
- Date Issued: 1997
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:57084 , xlink:href="https://doi.org/10.1016/S0277-5387(97)00045-4"
- Description: Photolysis, using a visible radiation, of diphthalocyanine complexes of NdIII, DyIII and LuIII ([Pc(−2)NdIIIPc(−2)]−, [Pc(−2)DyIIIPc(−2)]− and [Pc(−2)LuIIIPc(−2)]−, respectively) in the presence of pentachlorophenol (PCP) or SO2 results in the one-electron oxidation of the diphthalocyanine species to Pc(−1)NdIIIPc(−2), Pc(−1)DyIIIPc(−2) and Pc(−2)LuIIIPc(−2), respectively. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are of the order 10−4.
- Full Text:
- Date Issued: 1997
Redescription of three species of the genus Platypleura Amyot and Serville 1843 (Hemiptera Cicadidae)
- Authors: Villet, Martin H
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453827 , vital:75290 , https://doi.org/10.1080/03946975.1997.10539345
- Description: The type material of three platypleurine cicadas described by GERMAR (1834), Platypleura divisa, P. hirtipennis and P. plumosa, have been rediscovered and are redescribed to clarify their identity. Notes on their biology and biogeography are included.
- Full Text:
- Date Issued: 1997
- Authors: Villet, Martin H
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453827 , vital:75290 , https://doi.org/10.1080/03946975.1997.10539345
- Description: The type material of three platypleurine cicadas described by GERMAR (1834), Platypleura divisa, P. hirtipennis and P. plumosa, have been rediscovered and are redescribed to clarify their identity. Notes on their biology and biogeography are included.
- Full Text:
- Date Issued: 1997
Reflecting on socially transformative environmental literacy for Lesotho
- Mokuku, Tsepo, Lotz-Sisitka, Heila
- Authors: Mokuku, Tsepo , Lotz-Sisitka, Heila
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438769 , vital:73498 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137444"
- Description: This paper is an attempt to clarify the concept of environmental literacy from a socially transformative orientation. It resulted from our ongoing reflection on a conceptual framework in and for a three-year research project on education for environmental literacy within the integrated science curriculum in Lesotho.
- Full Text:
- Date Issued: 1997
- Authors: Mokuku, Tsepo , Lotz-Sisitka, Heila
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438769 , vital:73498 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137444"
- Description: This paper is an attempt to clarify the concept of environmental literacy from a socially transformative orientation. It resulted from our ongoing reflection on a conceptual framework in and for a three-year research project on education for environmental literacy within the integrated science curriculum in Lesotho.
- Full Text:
- Date Issued: 1997
Substituted catechols as complexing agents for the determination of bismuth, lead, copper and cadmium by adsorptive stripping voltammetry
- Limson, Janice L, Nyokong, Tebello
- Authors: Limson, Janice L , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293311 , vital:57074 , xlink:href="https://doi.org/10.1016/S0003-2670(96)00585-5"
- Description: Copper, cadmium, lead and bismuth (> 5 μg ml−1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4-t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed a different behaviour from the other three metals in that the highest current response was observed with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper.
- Full Text:
- Date Issued: 1997
- Authors: Limson, Janice L , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293311 , vital:57074 , xlink:href="https://doi.org/10.1016/S0003-2670(96)00585-5"
- Description: Copper, cadmium, lead and bismuth (> 5 μg ml−1) are determined by adsorptive cathodic stripping voltammetry (AdCSV) on a mercury film glassy carbon electrode, using catechol, 4-methylcatechol, 4-t-butylcatechol and resorcinol as complexing ligands. Complexes of lead, copper and bismuth with resorcinol showed the largest increase in current with increase in metal concentration, whereas complexes of these metals with 4-t-butylcatechol showed the lowest current response. Cadmium showed a different behaviour from the other three metals in that the highest current response was observed with 4-methylcatechol. The four metals could be determined simultaneously in the presence of resorcinol, although considerable interference was observed between bismuth and copper.
- Full Text:
- Date Issued: 1997
The cicada genus Stagira Stål 1861 (Homoptera Tibicinidae) systematic revision
- Authors: Villet, Martin H
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453903 , vital:75297 , https://doi.org/10.1080/03946975.1997.10539347
- Description: The cicada genus Stagira Stål 1861 is redescribed and re-vised. S. sanguinea Distant 1920 n. syn. and S. rufi-costata Distant 1920 n. syn. are synonymized with S. seg-mentaria Karsch ! 890, while S. aethlius (Walker 1850) n. stat. and S. acrida (Walker 1850) n. stat. are removed from the synonymy of S. simplex (Germar 1834) and restored to specific status. An additional 32 new species are described and a key is provided to the males of the genus. Stagira is endemic to the eastern tropical transitional area of south-ern Africa, and has occupied a variety of habitats, from xe-ric scrub to grassland savanna to forest. It forms a group with the South African genera Xosopsaltria Kirkaldy 1904, Tettigomyia Amyot and Serville 1843 and Bavea Distant 1905.
- Full Text:
- Date Issued: 1997
- Authors: Villet, Martin H
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453903 , vital:75297 , https://doi.org/10.1080/03946975.1997.10539347
- Description: The cicada genus Stagira Stål 1861 is redescribed and re-vised. S. sanguinea Distant 1920 n. syn. and S. rufi-costata Distant 1920 n. syn. are synonymized with S. seg-mentaria Karsch ! 890, while S. aethlius (Walker 1850) n. stat. and S. acrida (Walker 1850) n. stat. are removed from the synonymy of S. simplex (Germar 1834) and restored to specific status. An additional 32 new species are described and a key is provided to the males of the genus. Stagira is endemic to the eastern tropical transitional area of south-ern Africa, and has occupied a variety of habitats, from xe-ric scrub to grassland savanna to forest. It forms a group with the South African genera Xosopsaltria Kirkaldy 1904, Tettigomyia Amyot and Serville 1843 and Bavea Distant 1905.
- Full Text:
- Date Issued: 1997
The study of the interactions of cobalt (II) tetrasulfophthalocyanine with cysteine and histidine
- Sekota, Mantoa, Nyokong, Tebello
- Authors: Sekota, Mantoa , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293458 , vital:57087 , xlink:href="https://doi.org/10.1016/S0277-5387(97)00096-X"
- Description: Kinetics for the interaction of cobalt(II) tetrasulfophthalocyanine ([CoIITSPc]4−, Pc(−2) = phthalocyanine dianion) with the amino acids, histidine and cysteine, in pH 7.2 phosphate buffer were studied. The rates were found to be first order in both the [CoIITSPc]4− and the amino acid. The formation of the [CoIIITSPc]3− species in the presence of histidine occurred with a rate constant of 0.16 dm3 mol−s−1, whereas the formation of the [CoITSPc]5− species in the presence of cysteine gave a rate constant of 2.2 dm3 mol−1.
- Full Text:
- Date Issued: 1997
- Authors: Sekota, Mantoa , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293458 , vital:57087 , xlink:href="https://doi.org/10.1016/S0277-5387(97)00096-X"
- Description: Kinetics for the interaction of cobalt(II) tetrasulfophthalocyanine ([CoIITSPc]4−, Pc(−2) = phthalocyanine dianion) with the amino acids, histidine and cysteine, in pH 7.2 phosphate buffer were studied. The rates were found to be first order in both the [CoIITSPc]4− and the amino acid. The formation of the [CoIIITSPc]3− species in the presence of histidine occurred with a rate constant of 0.16 dm3 mol−s−1, whereas the formation of the [CoITSPc]5− species in the presence of cysteine gave a rate constant of 2.2 dm3 mol−1.
- Full Text:
- Date Issued: 1997
Towards sustainable conversation: Developing environmental education processes
- Authors: Le Roux, Kim
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389884 , vital:68492 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137446"
- Description: This paper highlights the importance of seeing environmental education as a process and considers the value of conversation and storytelling in environmental education processes. These processes are explored from a post-structural perspective within the context of the writer's own involvement in supporting environmental education processes.
- Full Text:
- Date Issued: 1997
- Authors: Le Roux, Kim
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389884 , vital:68492 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137446"
- Description: This paper highlights the importance of seeing environmental education as a process and considers the value of conversation and storytelling in environmental education processes. These processes are explored from a post-structural perspective within the context of the writer's own involvement in supporting environmental education processes.
- Full Text:
- Date Issued: 1997
Troubled waters in south-western New Georgia, Solomon Islands: Is codification of the commons a viable avenue for resource use regularisation
- Authors: Shankar, Aswani
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440061 , vital:73732
- Description: In recent decades there has been a growing interest in indigenous sea tenure institutions and their possible role in establishing a framework for sustainable resource use and conservation. Yet the feasibility of these institutions to cope with social and economic changes have been seldom explored. In this paper a case study is presented where internal deregularisation of the ‘commons’ is the result of existing socio-cultural principles combined with outside influences. Two territorial models are compared to elucidate emerging internal instabilities of sea tenure institutions and possible ways to correct existing problems. The codification of the commons is suggested here as a possible measure to strengthen indigenous common property regimes.
- Full Text:
- Date Issued: 1997
- Authors: Shankar, Aswani
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440061 , vital:73732
- Description: In recent decades there has been a growing interest in indigenous sea tenure institutions and their possible role in establishing a framework for sustainable resource use and conservation. Yet the feasibility of these institutions to cope with social and economic changes have been seldom explored. In this paper a case study is presented where internal deregularisation of the ‘commons’ is the result of existing socio-cultural principles combined with outside influences. Two territorial models are compared to elucidate emerging internal instabilities of sea tenure institutions and possible ways to correct existing problems. The codification of the commons is suggested here as a possible measure to strengthen indigenous common property regimes.
- Full Text:
- Date Issued: 1997
Use of cobalt (II) phthalocyanine to improve the sensitivity and stability of glassy carbon electrodes for the detection of cresols, chlorophenols and phenol
- Mafatle, Tsukutlane J, Nyokong, Tebello
- Authors: Mafatle, Tsukutlane J , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293335 , vital:57076 , xlink:href="https://doi.org/10.1016/S0003-2670(97)00464-9"
- Description: A cobalt(II) phthalocyanine-modified glassy carbon electrode (CoPc-GCE) was used for the detection of o-, m- and p-cresols, and of 2-chlorophenol, 4-chlorophenol and phenol. Modification of the glassy carbon electrode with CoPc increases the oxidation currents of these species and increases the stability of the electrode. CoPc-GCE showed less fouling by the oxidation products of these compounds than the unmodified GCE. Comparison of some first row transition metal phthalocyanines showed the following trend for the enhancement of the currents for the oxidation of cresols and phenols: Co(II)Pc > Mn(II)Pc > Fe(II)Pc > Ni(II)Pc > Cu(II)Pc > H2Pc > Zn(II)Pc > GCE. When [Co(II)TSPc]4− (TSPc=tetrasulfo Pc) was added to aqueous solutions containing the cresols and phenols, an enhancement of the oxidation currents was also observed.
- Full Text:
- Date Issued: 1997
- Authors: Mafatle, Tsukutlane J , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293335 , vital:57076 , xlink:href="https://doi.org/10.1016/S0003-2670(97)00464-9"
- Description: A cobalt(II) phthalocyanine-modified glassy carbon electrode (CoPc-GCE) was used for the detection of o-, m- and p-cresols, and of 2-chlorophenol, 4-chlorophenol and phenol. Modification of the glassy carbon electrode with CoPc increases the oxidation currents of these species and increases the stability of the electrode. CoPc-GCE showed less fouling by the oxidation products of these compounds than the unmodified GCE. Comparison of some first row transition metal phthalocyanines showed the following trend for the enhancement of the currents for the oxidation of cresols and phenols: Co(II)Pc > Mn(II)Pc > Fe(II)Pc > Ni(II)Pc > Cu(II)Pc > H2Pc > Zn(II)Pc > GCE. When [Co(II)TSPc]4− (TSPc=tetrasulfo Pc) was added to aqueous solutions containing the cresols and phenols, an enhancement of the oxidation currents was also observed.
- Full Text:
- Date Issued: 1997
Variation in foraging activity of Acanthochitona garnoti (Mollusca: Polyplacophora) from different habitats
- Cretchley, Robyn, Hodgson, Alan N, Gray David R, Reddy, Kasturi
- Authors: Cretchley, Robyn , Hodgson, Alan N , Gray David R , Reddy, Kasturi
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447642 , vital:74663 , https://www.ajol.info/index.php/az/article/view/154647
- Description: Activity of Acanthochitona garno {i was studied on an exposed horizon-tal platform of aeolian sandstone (I (enton-on-Sea-33'41'S; 26'40'E) and a quartzitic sandstone boulder shore (Cannon Rocks-33 44'S; 26'35'E), during 1994. In addition, the activity rhythms of chitons which were permanent inhabitants of high sbore rock pools at Kenton-on Sea were observed. All sites experienced semi-diurnal tides, the tidal range being about 1.9 m on mean spring tides. and 0.9 m on mean neap tides, with highest spring tides phased around.
- Full Text:
- Date Issued: 1997
- Authors: Cretchley, Robyn , Hodgson, Alan N , Gray David R , Reddy, Kasturi
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447642 , vital:74663 , https://www.ajol.info/index.php/az/article/view/154647
- Description: Activity of Acanthochitona garno {i was studied on an exposed horizon-tal platform of aeolian sandstone (I (enton-on-Sea-33'41'S; 26'40'E) and a quartzitic sandstone boulder shore (Cannon Rocks-33 44'S; 26'35'E), during 1994. In addition, the activity rhythms of chitons which were permanent inhabitants of high sbore rock pools at Kenton-on Sea were observed. All sites experienced semi-diurnal tides, the tidal range being about 1.9 m on mean spring tides. and 0.9 m on mean neap tides, with highest spring tides phased around.
- Full Text:
- Date Issued: 1997
Voltammetric behavior of cysteine and metallothionein on cobalt (II) tetrasulfonated phthalocyanine modified glassy carbon electrodes
- Limson, Janice L, Nyokong, Tebello
- Authors: Limson, Janice L , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293346 , vital:57077 , xlink:href="https://doi.org/10.1002/elan.1140090314"
- Description: Cysteine, and rat Cd, Zn-metallothionein (Cd, Zn-MT) have been studied electrochemically at glassy carbon electrodes modified with cobalt(II) tetrasulfonated phthalocyanine, [CoIITSPc]4−, where Pc(2-) = phthalocyanine dianion. The electrode was modified by electrodeposition of [CoIITSPc]4−. The anodic currents for the oxidation of cysteine on these electrodes are observed at 0.82 V (vs. Ag/AgCl) in acidic media. The anodic currents for the oxidation of Cd, Zn-MT are observed at 0.90 V at pH 8.4 (Tris buffer).
- Full Text:
- Date Issued: 1997
- Authors: Limson, Janice L , Nyokong, Tebello
- Date: 1997
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293346 , vital:57077 , xlink:href="https://doi.org/10.1002/elan.1140090314"
- Description: Cysteine, and rat Cd, Zn-metallothionein (Cd, Zn-MT) have been studied electrochemically at glassy carbon electrodes modified with cobalt(II) tetrasulfonated phthalocyanine, [CoIITSPc]4−, where Pc(2-) = phthalocyanine dianion. The electrode was modified by electrodeposition of [CoIITSPc]4−. The anodic currents for the oxidation of cysteine on these electrodes are observed at 0.82 V (vs. Ag/AgCl) in acidic media. The anodic currents for the oxidation of Cd, Zn-MT are observed at 0.90 V at pH 8.4 (Tris buffer).
- Full Text:
- Date Issued: 1997
A pre-impoundment study of the Sabie-Sand River system, Mpumalanga with special reference to predicted impacts on the Kruger National Park (Volume 3)
- O’Keeffe, Jay H, Weeks, D C, Fourie, A, Davies, B R
- Authors: O’Keeffe, Jay H , Weeks, D C , Fourie, A , Davies, B R
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437759 , vital:73407 , ISBN 1 86845 237 9 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/294-3-96.pdf
- Description: This project was begun in January 1990 in response to a need to characterise the fauna of the Sabie-Sand River system for which plans were already advanced to build impoundments. During the cource of the project, the region was subjected to the worst drought on record. As a result the scope and duration of the project was extended. This volume is the first of three which describe the results. Volume 1 de-scribes the ecological status of the Sabie, the Sand and other major tributaries of the system, including the diversity and distribution of the fish and macro-invertebrate faunas, and their habitat requirements. The second volume describes the results of a drought monitoring programme in which three reaches of the Sabie and one in the Sand River were intensively sampled throughout the worst drought on record, from 1991 to 1992. The purpose of this volume is to assess the probable effects of proposed impoundments in the Sabie-Sand River (both positive and nega-tive) on the ecology of the downstream reaches, and to draw on the information from volumes one and two to make recommendations for the management and monitoring of the flows in the river.
- Full Text:
- Date Issued: 1996
- Authors: O’Keeffe, Jay H , Weeks, D C , Fourie, A , Davies, B R
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437759 , vital:73407 , ISBN 1 86845 237 9 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/294-3-96.pdf
- Description: This project was begun in January 1990 in response to a need to characterise the fauna of the Sabie-Sand River system for which plans were already advanced to build impoundments. During the cource of the project, the region was subjected to the worst drought on record. As a result the scope and duration of the project was extended. This volume is the first of three which describe the results. Volume 1 de-scribes the ecological status of the Sabie, the Sand and other major tributaries of the system, including the diversity and distribution of the fish and macro-invertebrate faunas, and their habitat requirements. The second volume describes the results of a drought monitoring programme in which three reaches of the Sabie and one in the Sand River were intensively sampled throughout the worst drought on record, from 1991 to 1992. The purpose of this volume is to assess the probable effects of proposed impoundments in the Sabie-Sand River (both positive and nega-tive) on the ecology of the downstream reaches, and to draw on the information from volumes one and two to make recommendations for the management and monitoring of the flows in the river.
- Full Text:
- Date Issued: 1996
An extended version of Linda for Transputer systems
- Wells, George C, Clayton, Peter G, Chalmer, A G
- Authors: Wells, George C , Clayton, Peter G , Chalmer, A G
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430512 , vital:72696 , https://dl.acm.org/doi/abs/10.5555/270088.270117
- Description: This paper discusses the associative matching mechanism used in the Linda coordination language for the retrieval of data. There are a number of problems with this mechanism which are discussed in the light of the requirements of applications using Linda. A number of solutions to these problems have been proposed. These are discussed and compared with a new approach to solving these problems. The benefits and the limitations of the new approach are considered, showing how it provides a considerable improvement in this area.
- Full Text:
- Date Issued: 1996
- Authors: Wells, George C , Clayton, Peter G , Chalmer, A G
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430512 , vital:72696 , https://dl.acm.org/doi/abs/10.5555/270088.270117
- Description: This paper discusses the associative matching mechanism used in the Linda coordination language for the retrieval of data. There are a number of problems with this mechanism which are discussed in the light of the requirements of applications using Linda. A number of solutions to these problems have been proposed. These are discussed and compared with a new approach to solving these problems. The benefits and the limitations of the new approach are considered, showing how it provides a considerable improvement in this area.
- Full Text:
- Date Issued: 1996
Cicadas (Homoptera: Cicadidae) as indicators of habitat and veld condition in valley bushveld in the Great Fish River Valley, South Africa
- Villet, Martin H, Capitao, I R
- Authors: Villet, Martin H , Capitao, I R
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451670 , vital:75068 , https://journals.co.za/doi/pdf/10.10520/AJA10213589_213
- Description: Rural land-use in the Eastern Cape Province ranges from subsistence to commercial farming, with a few game reserves forming areas of active conservation. A large part of the Eastern Cape is covered by Valley Bushveld, a productive veld type dominating the Great Fish River Valley at elevations of 100-450 m (Dyer 1937; Acocks 1988). It is used for game, goat and cattle farming (Stuart-Hill 1991), but large areas have become degraded by overgrazing and invasion by alien or undesirable plants (La Cocket ai. 1990), often with an associated reduction in community richness (Dyer 1937; Acocks 1988). These effects are particularly persistent in this veld type because of the slow regeneration associated with severe climatic conditions (Dyer 1937; Lubke et ai. 1986; La Cock et al. 1990; Stuart-Hill 1991): a mean annual rainfall of only 350-500 mm, mainly between November and March, and temperatures peaking at 46 C in December and January (Acocks 1988). As a result, the more palatable plant species are becoming increasingly rare.
- Full Text:
- Date Issued: 1996
- Authors: Villet, Martin H , Capitao, I R
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451670 , vital:75068 , https://journals.co.za/doi/pdf/10.10520/AJA10213589_213
- Description: Rural land-use in the Eastern Cape Province ranges from subsistence to commercial farming, with a few game reserves forming areas of active conservation. A large part of the Eastern Cape is covered by Valley Bushveld, a productive veld type dominating the Great Fish River Valley at elevations of 100-450 m (Dyer 1937; Acocks 1988). It is used for game, goat and cattle farming (Stuart-Hill 1991), but large areas have become degraded by overgrazing and invasion by alien or undesirable plants (La Cocket ai. 1990), often with an associated reduction in community richness (Dyer 1937; Acocks 1988). These effects are particularly persistent in this veld type because of the slow regeneration associated with severe climatic conditions (Dyer 1937; Lubke et ai. 1986; La Cock et al. 1990; Stuart-Hill 1991): a mean annual rainfall of only 350-500 mm, mainly between November and March, and temperatures peaking at 46 C in December and January (Acocks 1988). As a result, the more palatable plant species are becoming increasingly rare.
- Full Text:
- Date Issued: 1996
Comparisons of the vocalizations and social behaviour of southern African Pycnonotus bulbuls
- Lloyd, Penn, Hulley, Patrick E, Craig, Adrian J F K
- Authors: Lloyd, Penn , Hulley, Patrick E , Craig, Adrian J F K
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447774 , vital:74673 , https://doi.org/10.1080/00306525.1996.9639696
- Description: Vocalizations and associated behaviour of three Pycnonotus species are described, based on field observations and tape recordings from which sonagrams were produced. These species, which are locally sym-patric and hybridize, have similar vocalizations and displays; differences are most apparent in their contact calls and songs. Quantitative analysis of the songs showed that P. barbatus and P. capensis are easily distinguished, whereas the song characteristics of P. nigricans overlap those of both the other species. Playback experiments with territorial male P. barbatus in an area of allopatry showed similar responses to songs of conspecifics and of P. nigricans, but almost no response to the song of P. capensis.
- Full Text:
- Date Issued: 1996
- Authors: Lloyd, Penn , Hulley, Patrick E , Craig, Adrian J F K
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447774 , vital:74673 , https://doi.org/10.1080/00306525.1996.9639696
- Description: Vocalizations and associated behaviour of three Pycnonotus species are described, based on field observations and tape recordings from which sonagrams were produced. These species, which are locally sym-patric and hybridize, have similar vocalizations and displays; differences are most apparent in their contact calls and songs. Quantitative analysis of the songs showed that P. barbatus and P. capensis are easily distinguished, whereas the song characteristics of P. nigricans overlap those of both the other species. Playback experiments with territorial male P. barbatus in an area of allopatry showed similar responses to songs of conspecifics and of P. nigricans, but almost no response to the song of P. capensis.
- Full Text:
- Date Issued: 1996
Cyclic voltammetry and spectroelectrochemistry of osmium phthalocyanines in aqueous and non-aqueous solvents
- Sekota, Mantoa, Nyokong, Tebello
- Authors: Sekota, Mantoa , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293358 , vital:57078 , xlink:href="https://doi.org/10.1016/0277-5387(95)00581-1"
- Description: Cyclic voltammetry of osmium phthalocyanine complexes, [(CN)2OsIIPc]2− and (py)2OSIIPc (PC = phthalocyanine dianion), show two oxidation couples and two reduction couples in acetonitrile and dimethy1formamide. Oxidation and reduction in these complexes occur at the ring to form cation and anion radical species, respectively. The [(CN)2OsIIPC]2− complexes show a remarkable ease of ring oxidation with oxidation potentials that are much lower than is typical for metallophthalocyanines. Half-wave potentials of 0.25 and 0.67 V (versus saturated calomel electrode, SCE) were obtained for the first and second ring oxidations, respectively. The [(CN)2OSIIPc]2− complex is soluble in water at pHs greater than 4. This complex shows one oxidation couple in pH 9 buffer at −0.11 V versus SCE.
- Full Text:
- Date Issued: 1996
- Authors: Sekota, Mantoa , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293358 , vital:57078 , xlink:href="https://doi.org/10.1016/0277-5387(95)00581-1"
- Description: Cyclic voltammetry of osmium phthalocyanine complexes, [(CN)2OsIIPc]2− and (py)2OSIIPc (PC = phthalocyanine dianion), show two oxidation couples and two reduction couples in acetonitrile and dimethy1formamide. Oxidation and reduction in these complexes occur at the ring to form cation and anion radical species, respectively. The [(CN)2OsIIPC]2− complexes show a remarkable ease of ring oxidation with oxidation potentials that are much lower than is typical for metallophthalocyanines. Half-wave potentials of 0.25 and 0.67 V (versus saturated calomel electrode, SCE) were obtained for the first and second ring oxidations, respectively. The [(CN)2OSIIPc]2− complex is soluble in water at pHs greater than 4. This complex shows one oxidation couple in pH 9 buffer at −0.11 V versus SCE.
- Full Text:
- Date Issued: 1996