Tuning the physico-electrochemical properties of novel cobalt (II) octa [(3, 5-biscarboxylate)-phenoxy] phthalocyanine complex using phenylamine-functionalised SWCNTs
- Agboola, Bolade O, Ozoemena, Kenneth I, Nyokong, Tebello, Fukuda, Takamitsu, Kobayashi, Nagao
- Authors: Agboola, Bolade O , Ozoemena, Kenneth I , Nyokong, Tebello , Fukuda, Takamitsu , Kobayashi, Nagao
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261692 , vital:53435 , xlink:href="https://doi.org/10.1016/j.carbon.2009.10.023"
- Description: The integration of phenylamine-functionalised SWCNTs (SWCNT-phenylamine) with a novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine (CoOBPPc) complex has been described. The physical and electrochemical properties of the CoOBPPc-SWCNT-phenylamine hybrid were evaluated using spectroscopy (IR and UV–vis), field emission scanning electron microscopy and electrochemistry (cyclic voltammetry and electrochemical impedance spectroscopy). Integration of SWCNT-phenylamine resulted in the physical transformation of the CoOBCPPc from the usually bluish colour of cobalt phthalocyanine complexes to a beautiful bright green colour. In addition, the heterogeneous electron transfer kinetics and electrocatalytic properties of the CoOBCPPc were greatly enhanced following the attachment of the SWCNT-phenylamine. The potential electrocatalytic application of the hybrid was tested using β-nicotinamide adenine dinucleotide (NADH) as a model biological analyte. Interestingly, the onset oxidation potential of this analyte was significantly reduced (300 mV) by this hybrid compared to the bare electrode.
- Full Text:
- Date Issued: 2010
- Authors: Agboola, Bolade O , Ozoemena, Kenneth I , Nyokong, Tebello , Fukuda, Takamitsu , Kobayashi, Nagao
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261692 , vital:53435 , xlink:href="https://doi.org/10.1016/j.carbon.2009.10.023"
- Description: The integration of phenylamine-functionalised SWCNTs (SWCNT-phenylamine) with a novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine (CoOBPPc) complex has been described. The physical and electrochemical properties of the CoOBPPc-SWCNT-phenylamine hybrid were evaluated using spectroscopy (IR and UV–vis), field emission scanning electron microscopy and electrochemistry (cyclic voltammetry and electrochemical impedance spectroscopy). Integration of SWCNT-phenylamine resulted in the physical transformation of the CoOBCPPc from the usually bluish colour of cobalt phthalocyanine complexes to a beautiful bright green colour. In addition, the heterogeneous electron transfer kinetics and electrocatalytic properties of the CoOBCPPc were greatly enhanced following the attachment of the SWCNT-phenylamine. The potential electrocatalytic application of the hybrid was tested using β-nicotinamide adenine dinucleotide (NADH) as a model biological analyte. Interestingly, the onset oxidation potential of this analyte was significantly reduced (300 mV) by this hybrid compared to the bare electrode.
- Full Text:
- Date Issued: 2010
Fabrication and characterization of single walled carbon nanotubes-iron phthalocyanine nano-composite
- Akinbulu, Isaac A, Nyokong, Tebello
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262622 , vital:53537 , xlink:href="https://doi.org/10.1039/C0NJ00395F"
- Description: Nano-composite of single walled carbon nanotubes (SWCNTs) and iron phthalocyanine, peripherally tetra-substituted with diethylaminoethanethiol (complex 2), was fabricated and characterized by infra red (IR) spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM technique gave a convincing image of the nano-composite. Self-assembled monolayer (SAM) film of the composite (SWCNT-2-SAM) was formed on gold electrode. Its surface properties were investigated, relative to that of 2-SAM film, by cyclic voltammetry and scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry, using [Fe(CN)6]3− as redox probe, were used to investigate the dynamics of electron transport in the SWCNT-2-SAM film. Lower charge transfer resistance, RCT, of the SWCNT-2-SAM modified Au electrode, relative to that of the 2-SAM modified Au electrode, was an indication of enhanced electron transport in the presence of SWCNT. The SAM film of the nano-composite showed better electrocatalytic behaviour, relative to that of 2-SAM film, towards the oxidation of the insecticide, carbofuran. The electrode (SWCNT-2-SAM) showed good selectivity for carbofuran, in the presence of diazinon (a non-electroactive interferent) and at lower concentration of the electroactive interferents (chlorpyrifos and dichlorfos).
- Full Text:
- Date Issued: 2010
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262622 , vital:53537 , xlink:href="https://doi.org/10.1039/C0NJ00395F"
- Description: Nano-composite of single walled carbon nanotubes (SWCNTs) and iron phthalocyanine, peripherally tetra-substituted with diethylaminoethanethiol (complex 2), was fabricated and characterized by infra red (IR) spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM technique gave a convincing image of the nano-composite. Self-assembled monolayer (SAM) film of the composite (SWCNT-2-SAM) was formed on gold electrode. Its surface properties were investigated, relative to that of 2-SAM film, by cyclic voltammetry and scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry, using [Fe(CN)6]3− as redox probe, were used to investigate the dynamics of electron transport in the SWCNT-2-SAM film. Lower charge transfer resistance, RCT, of the SWCNT-2-SAM modified Au electrode, relative to that of the 2-SAM modified Au electrode, was an indication of enhanced electron transport in the presence of SWCNT. The SAM film of the nano-composite showed better electrocatalytic behaviour, relative to that of 2-SAM film, towards the oxidation of the insecticide, carbofuran. The electrode (SWCNT-2-SAM) showed good selectivity for carbofuran, in the presence of diazinon (a non-electroactive interferent) and at lower concentration of the electroactive interferents (chlorpyrifos and dichlorfos).
- Full Text:
- Date Issued: 2010
Syntheses and investigation of the effects of position and nature of substituent on the spectral, electrochemical and spectroelectrochemical properties of new cobalt phthalocyanine complexes
- Akinbulu, Isaac A, Nyokong, Tebello
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261677 , vital:53434 , xlink:href="https://doi.org/10.1016/j.poly.2010.01.004"
- Description: The syntheses of new cobalt phthalocyanine (CoPc) complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral (complex 3b) positions, and with benzylmercapto at the non-peripheral position (complex 5), are reported. The effects of the nature and position of substituent on the spectral, electrochemical and spectroelectrochemical properties of these complexes are investigated. Solution electrochemistry of complex 3a showed three distinctly resolved redox processes attributed to CoIIIPc−2/CoIIPc−2 (E½ = +0.64 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.24 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.26 V versus Ag|AgCl) species. No ring oxidation was observed in complex 3a. Complex 3b showed both ring-based oxidation, attributed to CoIIIPc−1/CoIIIPc−2 species (Ep = +0.86 V versus Ag|AgCl), and ring-based reduction associated with CoIPc−2/CoIPc−3 species (E½ = −1.46 V versus Ag|AgCl), with the normal metal-based redox processes in CoPc complexes: CoIIIPc−2/CoIIPc−2 (Ep = +0.41 V versus Ag|AgCl) and CoIIPc−2/CoIPc−2 (E½ = −0.38 V versus Ag|AgCl). Solution electrochemistry of complex 5 showed the same type and number of species observed in complex 3a: CoIIIPc−2/CoIIPc−2 (Ep = +0.59 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.26 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.39 V versus Ag|AgCl) species. These processes were confirmed using spectroelectrochemistry.
- Full Text:
- Date Issued: 2010
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261677 , vital:53434 , xlink:href="https://doi.org/10.1016/j.poly.2010.01.004"
- Description: The syntheses of new cobalt phthalocyanine (CoPc) complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral (complex 3b) positions, and with benzylmercapto at the non-peripheral position (complex 5), are reported. The effects of the nature and position of substituent on the spectral, electrochemical and spectroelectrochemical properties of these complexes are investigated. Solution electrochemistry of complex 3a showed three distinctly resolved redox processes attributed to CoIIIPc−2/CoIIPc−2 (E½ = +0.64 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.24 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.26 V versus Ag|AgCl) species. No ring oxidation was observed in complex 3a. Complex 3b showed both ring-based oxidation, attributed to CoIIIPc−1/CoIIIPc−2 species (Ep = +0.86 V versus Ag|AgCl), and ring-based reduction associated with CoIPc−2/CoIPc−3 species (E½ = −1.46 V versus Ag|AgCl), with the normal metal-based redox processes in CoPc complexes: CoIIIPc−2/CoIIPc−2 (Ep = +0.41 V versus Ag|AgCl) and CoIIPc−2/CoIPc−2 (E½ = −0.38 V versus Ag|AgCl). Solution electrochemistry of complex 5 showed the same type and number of species observed in complex 3a: CoIIIPc−2/CoIIPc−2 (Ep = +0.59 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.26 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.39 V versus Ag|AgCl) species. These processes were confirmed using spectroelectrochemistry.
- Full Text:
- Date Issued: 2010
The effects of point of substitution on the electrochemical behavior of new manganese phthalocyanines, tetra-substituted with diethylaminoethanethiol
- Akinbulu, Isaac Adebayo, Nyokong, Tebello
- Authors: Akinbulu, Isaac Adebayo , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249137 , vital:51781 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.003"
- Description: The syntheses and comparative studies of the spectral, voltammetry and spectroelectrochemical properties of new manganese phthalocyanine complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral positions (complex 3b) are reported. Solution electrochemistry of complex 3a showed quasi-reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.07 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.78 V vs. Ag|AgCl) reductions, but no ring-based oxidation. However, complex 3b showed weak irreversible ring-oxidation signal (Ep = +0.86 vs. Ag|AgCl). Reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.04 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.68 V vs. Ag|AgCl) reductions were also observed for complex 3b. Spectroelectrochemistry was used to confirm these processes. Reduction process involving the metal (MnIIIPc−2/MnIIPc−2) was associated with the formation of manganese μ-oxo complex in complex 3a.
- Full Text:
- Date Issued: 2010
- Authors: Akinbulu, Isaac Adebayo , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249137 , vital:51781 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.003"
- Description: The syntheses and comparative studies of the spectral, voltammetry and spectroelectrochemical properties of new manganese phthalocyanine complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral positions (complex 3b) are reported. Solution electrochemistry of complex 3a showed quasi-reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.07 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.78 V vs. Ag|AgCl) reductions, but no ring-based oxidation. However, complex 3b showed weak irreversible ring-oxidation signal (Ep = +0.86 vs. Ag|AgCl). Reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.04 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.68 V vs. Ag|AgCl) reductions were also observed for complex 3b. Spectroelectrochemistry was used to confirm these processes. Reduction process involving the metal (MnIIIPc−2/MnIIPc−2) was associated with the formation of manganese μ-oxo complex in complex 3a.
- Full Text:
- Date Issued: 2010
The effects of point of substitution on the formation of manganese phthalocyanine-based molecular materials
- Akinbulu, Isaac Adebayo, Khene, Samson, Nyokong, Tebello
- Authors: Akinbulu, Isaac Adebayo , Khene, Samson , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249103 , vital:51778 , xlink:href="https://doi.org/10.1016/j.tsf.2010.08.145"
- Description: Molecular films of manganese phthalocyanine (MnPc) complexes, tetra-substituted with 2-diethylaminoethanethio at the peripheral (Mn(OAc)-β-TDEAETPc, 1) and non-peripheral (Mn(OAc)-α-TDEAETPc, 2) positions were formed on glassy carbon electrode by electropolymerization and electrodeposition respectively. Atomic force microscopy images confirmed the presence of the films and revealed significant morphological differences. The films exhibited an electrocatalytic activity towards the oxidation of the insecticide, bendiocarb. Hydrodynamic technique, using rotating disc electrode voltammetry, was used to investigate the kinetics of electro-oxidation of the insecticide. Morphological differences of the films significantly influenced kinetic parameters. Values of Tafel slopes, obtained from Tafel plots, suggested that catalysis of bendiocarb occurred via outer sphere mechanism.
- Full Text:
- Date Issued: 2010
- Authors: Akinbulu, Isaac Adebayo , Khene, Samson , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249103 , vital:51778 , xlink:href="https://doi.org/10.1016/j.tsf.2010.08.145"
- Description: Molecular films of manganese phthalocyanine (MnPc) complexes, tetra-substituted with 2-diethylaminoethanethio at the peripheral (Mn(OAc)-β-TDEAETPc, 1) and non-peripheral (Mn(OAc)-α-TDEAETPc, 2) positions were formed on glassy carbon electrode by electropolymerization and electrodeposition respectively. Atomic force microscopy images confirmed the presence of the films and revealed significant morphological differences. The films exhibited an electrocatalytic activity towards the oxidation of the insecticide, bendiocarb. Hydrodynamic technique, using rotating disc electrode voltammetry, was used to investigate the kinetics of electro-oxidation of the insecticide. Morphological differences of the films significantly influenced kinetic parameters. Values of Tafel slopes, obtained from Tafel plots, suggested that catalysis of bendiocarb occurred via outer sphere mechanism.
- Full Text:
- Date Issued: 2010
Photophysical and photochemical parameters of octakis (benzylthio) phthalocyaninato zinc, aluminium and tin
- Akpe, Victor, Brismar, Hjalmar, Nyokong, Tebello, Osadebe, Patience Ogoamak
- Authors: Akpe, Victor , Brismar, Hjalmar , Nyokong, Tebello , Osadebe, Patience Ogoamak
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248472 , vital:51689 , xlink:href="https://doi.org/10.1016/j.molstruc.2010.08.033"
- Description: This paper addresses the synthesis of octa-substituted benzylthio metallophthalocyanines (OBTMPcs) that contain the central metal ions of Zn2+, Al3+ and Sn4+. The ground state absorption of ZnPc(SR)8 (OBTZnPc) along with the ZnPc derivatives, well documented in literature were used to study a new concept called the red shift index (RsI). The concept is based on the empirical values of RsI of the different complexes in solvent media. Unequivocally, parameters used in this paper show strong correlations that are consistent with the results obtained. For instance, RsI of the complexes tend to increase as the refractive index, nD, and solvent donor, DN, of solvent increases. Photodegradation (photobleaching) quantum yield, ϕd measurements of these compounds show that they are highly photostable, ϕd (0.03–0.33 × 10−5). The triplet quantum yield, ϕT (0.40–0.53) and the triplet lifetime, τT (610–810 μs) are within the typical range for metallophthalocyanines in DMSO. The photosensitisation efficiency, SΔ, is relatively high for all the molecules (0.74–0.90).
- Full Text:
- Date Issued: 2010
- Authors: Akpe, Victor , Brismar, Hjalmar , Nyokong, Tebello , Osadebe, Patience Ogoamak
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248472 , vital:51689 , xlink:href="https://doi.org/10.1016/j.molstruc.2010.08.033"
- Description: This paper addresses the synthesis of octa-substituted benzylthio metallophthalocyanines (OBTMPcs) that contain the central metal ions of Zn2+, Al3+ and Sn4+. The ground state absorption of ZnPc(SR)8 (OBTZnPc) along with the ZnPc derivatives, well documented in literature were used to study a new concept called the red shift index (RsI). The concept is based on the empirical values of RsI of the different complexes in solvent media. Unequivocally, parameters used in this paper show strong correlations that are consistent with the results obtained. For instance, RsI of the complexes tend to increase as the refractive index, nD, and solvent donor, DN, of solvent increases. Photodegradation (photobleaching) quantum yield, ϕd measurements of these compounds show that they are highly photostable, ϕd (0.03–0.33 × 10−5). The triplet quantum yield, ϕT (0.40–0.53) and the triplet lifetime, τT (610–810 μs) are within the typical range for metallophthalocyanines in DMSO. The photosensitisation efficiency, SΔ, is relatively high for all the molecules (0.74–0.90).
- Full Text:
- Date Issued: 2010
A tale of 2 investigations:
- Authors: Amner, Roderick J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159438 , vital:40297 , https://hdl.handle.net/10520/EJC139354
- Description: This is a tale of two in-depth stories, both produced by one Daily Dispatch journalist, Gcina Nstaluba, in 2009. One was wildly successful - it helped change the face of the government's housing policy and won Ntsaluba SA Story of the Year at the 2010 Mondi Shanduka Newspaper Awards. The other was deemed a dismal failure by Ntsaluba himself. Why? And what can these stories teach us and our students about doing journalism in South Africa?
- Full Text:
- Date Issued: 2010
- Authors: Amner, Roderick J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159438 , vital:40297 , https://hdl.handle.net/10520/EJC139354
- Description: This is a tale of two in-depth stories, both produced by one Daily Dispatch journalist, Gcina Nstaluba, in 2009. One was wildly successful - it helped change the face of the government's housing policy and won Ntsaluba SA Story of the Year at the 2010 Mondi Shanduka Newspaper Awards. The other was deemed a dismal failure by Ntsaluba himself. Why? And what can these stories teach us and our students about doing journalism in South Africa?
- Full Text:
- Date Issued: 2010
Promoting entrepreneurship in agriculture in the Eastern Cape:
- Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143067 , vital:38198 , DOI: 10.1080/03031853.1994.9524779
- Description: Selected cases in developing entrepreneurship in small-scale subsistence and commercial agriculture in the Eastern Cape are examined, including the provision of marketing facilities, the training programme of the Africa Cooperative Action Trust (ACAT) in Ciskei, government sponsored irrigation projects and the farmer support programme. An attempt is made to draw general conclusions about the necessary ingredients for successful entrepreneurship and the formulation of proposals for further promoting entrepreneurship in agriculture in South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143067 , vital:38198 , DOI: 10.1080/03031853.1994.9524779
- Description: Selected cases in developing entrepreneurship in small-scale subsistence and commercial agriculture in the Eastern Cape are examined, including the provision of marketing facilities, the training programme of the Africa Cooperative Action Trust (ACAT) in Ciskei, government sponsored irrigation projects and the farmer support programme. An attempt is made to draw general conclusions about the necessary ingredients for successful entrepreneurship and the formulation of proposals for further promoting entrepreneurship in agriculture in South Africa.
- Full Text:
- Date Issued: 2010
The role of processors, wholesalers and retailers in the marketing of food in South Africa:
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143090 , vital:38200 , DOI: 10.1080/03031853.1979.9524558
- Description: The importance of the middlemen of marketing was recently high-lighted with the publication of a thirty item 'food basket' for South Africa. While the producer's share of the foodbasket is usually of chief interest to the farmers of our country and often to agricultural economists, the field of traditional agricultural marketing takes in the whole area from farm gate to consumer's table.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143090 , vital:38200 , DOI: 10.1080/03031853.1979.9524558
- Description: The importance of the middlemen of marketing was recently high-lighted with the publication of a thirty item 'food basket' for South Africa. While the producer's share of the foodbasket is usually of chief interest to the farmers of our country and often to agricultural economists, the field of traditional agricultural marketing takes in the whole area from farm gate to consumer's table.
- Full Text:
- Date Issued: 2010
The commercial agricultural economy of the East Cape: Die kommersiële landbou-ekonomie van die Oos-Kaap
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143079 , vital:38199 , DOI: 10.1080/03031853.1991.9524228
- Description: The East Cape, and in particular the Smaldeel area, is used to exemplify some of the characteristics and problems of commercial farming over a period of about three decades to serve as a backdrop for the broader theme of normalising South African agriculture. The regional economy is dominated by Port Elizabeth-Uitenhage and East London which account for most of the population and three-fourths of the Gross Geographic Product (GGP). Agriculture accounts for only 10% of GGP, but is one of the most labour intensive sectors in a region with 24% of its population unemployed. The agricultural economy of the region is very diversified, but livestock farming plays the most important part in all areas contributing 72% of gross income. The chief changes which have occured in East Cape farming, as elsewhere, have been the decline in the number of farms and increase in farm size, greater capital investment, increased specialisation and declining employment.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143079 , vital:38199 , DOI: 10.1080/03031853.1991.9524228
- Description: The East Cape, and in particular the Smaldeel area, is used to exemplify some of the characteristics and problems of commercial farming over a period of about three decades to serve as a backdrop for the broader theme of normalising South African agriculture. The regional economy is dominated by Port Elizabeth-Uitenhage and East London which account for most of the population and three-fourths of the Gross Geographic Product (GGP). Agriculture accounts for only 10% of GGP, but is one of the most labour intensive sectors in a region with 24% of its population unemployed. The agricultural economy of the region is very diversified, but livestock farming plays the most important part in all areas contributing 72% of gross income. The chief changes which have occured in East Cape farming, as elsewhere, have been the decline in the number of farms and increase in farm size, greater capital investment, increased specialisation and declining employment.
- Full Text:
- Date Issued: 2010
Beyond teaching language: towards terminological primacy in learners' geometric conceptualisation
- Atebe, Humphrey U, Schäfer, Marc
- Authors: Atebe, Humphrey U , Schäfer, Marc
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140960 , vital:37932 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20922
- Description: This paper reports on a specific aspect of a broader geometry conceptualisation study that sought to explore and explicate learners' knowledge of basic geometric terminology in selected Nigerian and South African high schools. It is framed by the notion that students' acquisition of the correct terminology in school geometry is important for their success in the subject. The original study further aimed to determine the relationship that might exist between a learner's ability in verbal geometry terminology tasks and his/her ability in visual geometry terminology tasks. A total of 144 learners (72 each from South Africa and Nigeria) were selected for the study, using both the stratified and the fish-bowl sampling techniques. A questionnaire consisting of a sixty-item multiple-choice objective test provided the data for the study. An overall percentage mean score of 44,17% obtained in the test indicated that learners in this study had only a limited knowledge of basic geometric terminology. The Nigerian subsample in the study had a weaker understanding of basic geometric terminology than their South African counterparts. Importantly, there were high positive correlations between participants' ability in verbal geometry terminology tasks and their ability in visual geometry terminology tasks. These results are consistent with those of several earlier studies, and provide a reasonably firm basis for certain recommendations to be made.
- Full Text:
- Date Issued: 2010
- Authors: Atebe, Humphrey U , Schäfer, Marc
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140960 , vital:37932 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20922
- Description: This paper reports on a specific aspect of a broader geometry conceptualisation study that sought to explore and explicate learners' knowledge of basic geometric terminology in selected Nigerian and South African high schools. It is framed by the notion that students' acquisition of the correct terminology in school geometry is important for their success in the subject. The original study further aimed to determine the relationship that might exist between a learner's ability in verbal geometry terminology tasks and his/her ability in visual geometry terminology tasks. A total of 144 learners (72 each from South Africa and Nigeria) were selected for the study, using both the stratified and the fish-bowl sampling techniques. A questionnaire consisting of a sixty-item multiple-choice objective test provided the data for the study. An overall percentage mean score of 44,17% obtained in the test indicated that learners in this study had only a limited knowledge of basic geometric terminology. The Nigerian subsample in the study had a weaker understanding of basic geometric terminology than their South African counterparts. Importantly, there were high positive correlations between participants' ability in verbal geometry terminology tasks and their ability in visual geometry terminology tasks. These results are consistent with those of several earlier studies, and provide a reasonably firm basis for certain recommendations to be made.
- Full Text:
- Date Issued: 2010
Cyber security: Challenges and the way forward
- Ayofe, Azeez N, Irwin, Barry V W
- Authors: Ayofe, Azeez N , Irwin, Barry V W
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428613 , vital:72524 , https://d1wqtxts1xzle7.cloudfront.net/62565276/171920200330-53981-1mqgyr5.pdf?1585592737=andresponse-content-disposi-tion=inline%3B+filename%3DCYBER_SECURITY_CHALLENGES_AND_THE_WAY_FO.pdfandExpires=1714729368andSignature=dPUCAd1sMUF-gyDTkBFb2lzDvkVNpfp0sk1z-CdAeHH6O759dBiO-M158drmJsOo1XtOJBY4tNd8Um2gi11zw4U8yEzHO-bGUJGJTJcooTXaKwZLT-wPqS779Qo2oeiQOIiuAx6zSdcfSGjbDfFOL1YWV9UeKvhtcnGJ3p-CjJAhiPWJorGn1-z8mO6oouWzyJYc0hV0-Po8yywJD60eC2S6llQmfNRpX4otgq4fgZwZu4TEcMUWPfBzGPFPNYcCLfiQVK0YLV~XdTCWrhTlYPSMzVSs~DhQk9QPBU7IGmzQkGZo3UXnNu1slCVLb9Dqm~9DSbmttIXIDGYXEjP9l4w__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: The high level of insecurity on the internet is becoming worrisome so much so that transaction on the web has become a thing of doubt. Cy-bercrime is becoming ever more serious and prevalent. Findings from 2002 Computer Crime and Security Survey show an upward trend that demonstrates a need for a timely review of existing approaches to fighting this new phenomenon in the information age. In this paper, we provide an overview of Cybercrime and present an international per-spective on fighting Cybercrime. This work seeks to define the concept of cyber-crime, explain tools being used by the criminals to perpetrate their evil handiworks, identify reasons for cyber-crime, how it can be eradicated, look at those involved and the reasons for their involve-ment, we would look at how best to detect a criminal mail and in conclu-sion, proffer recommendations that would help in checking the increas-ing rate of cyber-crimes and criminals.
- Full Text:
- Date Issued: 2010
- Authors: Ayofe, Azeez N , Irwin, Barry V W
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428613 , vital:72524 , https://d1wqtxts1xzle7.cloudfront.net/62565276/171920200330-53981-1mqgyr5.pdf?1585592737=andresponse-content-disposi-tion=inline%3B+filename%3DCYBER_SECURITY_CHALLENGES_AND_THE_WAY_FO.pdfandExpires=1714729368andSignature=dPUCAd1sMUF-gyDTkBFb2lzDvkVNpfp0sk1z-CdAeHH6O759dBiO-M158drmJsOo1XtOJBY4tNd8Um2gi11zw4U8yEzHO-bGUJGJTJcooTXaKwZLT-wPqS779Qo2oeiQOIiuAx6zSdcfSGjbDfFOL1YWV9UeKvhtcnGJ3p-CjJAhiPWJorGn1-z8mO6oouWzyJYc0hV0-Po8yywJD60eC2S6llQmfNRpX4otgq4fgZwZu4TEcMUWPfBzGPFPNYcCLfiQVK0YLV~XdTCWrhTlYPSMzVSs~DhQk9QPBU7IGmzQkGZo3UXnNu1slCVLb9Dqm~9DSbmttIXIDGYXEjP9l4w__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: The high level of insecurity on the internet is becoming worrisome so much so that transaction on the web has become a thing of doubt. Cy-bercrime is becoming ever more serious and prevalent. Findings from 2002 Computer Crime and Security Survey show an upward trend that demonstrates a need for a timely review of existing approaches to fighting this new phenomenon in the information age. In this paper, we provide an overview of Cybercrime and present an international per-spective on fighting Cybercrime. This work seeks to define the concept of cyber-crime, explain tools being used by the criminals to perpetrate their evil handiworks, identify reasons for cyber-crime, how it can be eradicated, look at those involved and the reasons for their involve-ment, we would look at how best to detect a criminal mail and in conclu-sion, proffer recommendations that would help in checking the increas-ing rate of cyber-crimes and criminals.
- Full Text:
- Date Issued: 2010
Natural enemies from South Africa for biological control of Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae) in Europe
- Baars, Jan-Robert, Coetzee, Julie A, Martin, Grant D, Hill, Martin P, Caffrey, J M
- Authors: Baars, Jan-Robert , Coetzee, Julie A , Martin, Grant D , Hill, Martin P , Caffrey, J M
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76914 , vital:30637 , https://doi.org/10.1007/s10750-010-0427-0
- Description: The non-native invasive plant, Lagarosiphon major (Hydrocharitaceae) is a submersed aquatic macrophyte that poses a significant threat to water bodies in Europe. Dense infestations prove difficult to manage using traditional methods. In order to initiate a biocontrol programme, a survey for natural enemies of Lagarosiphon was conducted in South Africa. Several phytophagous species were recorded for the first time, with at least three showing notable promise as candidate agents. Amongst these, a leaf-mining fly, Hydrellia sp. (Ephydridae) that occurred over a wide distribution causes significant leaf damage despite high levels of parasitism by braconid wasps. Another yet unidentified fly was recorded mining the stem of L. major. Two leaf-feeding and shoot boring weevils, cf. Bagous sp. (Curculionidae) were recorded damaging the shoot tips and stunting the growth of the stem. Several leaf-feeding lepidopteran species (Nymphulinae) were frequently recorded, but are expected to feed on a wide range of plant species and are not considered for importation before other candidates are assessed. The discovery of several natural enemies in the country of origin improves the biological control prospects of L. major in Europe.
- Full Text:
- Date Issued: 2010
- Authors: Baars, Jan-Robert , Coetzee, Julie A , Martin, Grant D , Hill, Martin P , Caffrey, J M
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76914 , vital:30637 , https://doi.org/10.1007/s10750-010-0427-0
- Description: The non-native invasive plant, Lagarosiphon major (Hydrocharitaceae) is a submersed aquatic macrophyte that poses a significant threat to water bodies in Europe. Dense infestations prove difficult to manage using traditional methods. In order to initiate a biocontrol programme, a survey for natural enemies of Lagarosiphon was conducted in South Africa. Several phytophagous species were recorded for the first time, with at least three showing notable promise as candidate agents. Amongst these, a leaf-mining fly, Hydrellia sp. (Ephydridae) that occurred over a wide distribution causes significant leaf damage despite high levels of parasitism by braconid wasps. Another yet unidentified fly was recorded mining the stem of L. major. Two leaf-feeding and shoot boring weevils, cf. Bagous sp. (Curculionidae) were recorded damaging the shoot tips and stunting the growth of the stem. Several leaf-feeding lepidopteran species (Nymphulinae) were frequently recorded, but are expected to feed on a wide range of plant species and are not considered for importation before other candidates are assessed. The discovery of several natural enemies in the country of origin improves the biological control prospects of L. major in Europe.
- Full Text:
- Date Issued: 2010
Upstart-the paper for youth by the youth
- Authors: Badat, Shireen
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454961 , vital:75390 , https://hdl.handle.net/10520/EJC139339
- Description: The city of Grahamstown in the Eastern Cape is renowned for its edu-cational institutions. With Rhodes University the backbone of the city's economic activity, Grahamstown is also home to prestigious private schools like St Andrew's, Kingswood and DSG - noted for schooling the captains of industry and children of the new political and economic elite.
- Full Text:
- Date Issued: 2010
- Authors: Badat, Shireen
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454961 , vital:75390 , https://hdl.handle.net/10520/EJC139339
- Description: The city of Grahamstown in the Eastern Cape is renowned for its edu-cational institutions. With Rhodes University the backbone of the city's economic activity, Grahamstown is also home to prestigious private schools like St Andrew's, Kingswood and DSG - noted for schooling the captains of industry and children of the new political and economic elite.
- Full Text:
- Date Issued: 2010
Site of struggle: the Freedom Park fracas and the divisive legacy of South Africa’s Border War/Liberation Struggle
- Authors: Baines, Gary F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126954 , vital:35938 , https://doi.10.1080/02533950903076428
- Description: In South Africa, Carcharias taurus is commonly known as the ragged-tooth shark or raggie. The species is also referred to as the sand-tiger shark in North America and as the grey-nurse shark in Australia. It is a long-lived species with an estimated longevity of up to 40 years (Goldman 2002). Female sharks reach sexual maturity at approximately 10 years (Goldman 2002), and they exhibit a biennial reproductive cycle (Branstetter and Musick 1994, Lucifora et al. 2002, G Cliff, Natal Sharks Board, unpublished data). Intra-uterine cannibalisation results in a maximum fecundity of two pups per litter after a gestation period of approximately 9–12 months (Bass et al. 1975, Gilmore et al. 1983). These life-history characteristics make this species particularly susceptible to overexploitation.
- Full Text:
- Date Issued: 2010
- Authors: Baines, Gary F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126954 , vital:35938 , https://doi.10.1080/02533950903076428
- Description: In South Africa, Carcharias taurus is commonly known as the ragged-tooth shark or raggie. The species is also referred to as the sand-tiger shark in North America and as the grey-nurse shark in Australia. It is a long-lived species with an estimated longevity of up to 40 years (Goldman 2002). Female sharks reach sexual maturity at approximately 10 years (Goldman 2002), and they exhibit a biennial reproductive cycle (Branstetter and Musick 1994, Lucifora et al. 2002, G Cliff, Natal Sharks Board, unpublished data). Intra-uterine cannibalisation results in a maximum fecundity of two pups per litter after a gestation period of approximately 9–12 months (Bass et al. 1975, Gilmore et al. 1983). These life-history characteristics make this species particularly susceptible to overexploitation.
- Full Text:
- Date Issued: 2010
A conceptually relevant and practically sophisticated journalism syllabus for Africa
- Authors: Banda, Fackson
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454547 , vital:75354 , https://hdl.handle.net/10520/EJC139370
- Description: Over 35 African journalism educators gathered in Grahamstown, South Africa in September last year, at the invitation of the SAB Ltd-Unesco Chair of Media and Democracy, to present and discuss initial research papers aimed at defining a common vision of journalism education on the African continent. The meeting was held against the backdrop of the bid by Rhodes University, under the auspices of the School of Journalism and Media Studies, to host the 2nd World Journalism Education Congress (WJEC).
- Full Text:
- Date Issued: 2010
- Authors: Banda, Fackson
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454547 , vital:75354 , https://hdl.handle.net/10520/EJC139370
- Description: Over 35 African journalism educators gathered in Grahamstown, South Africa in September last year, at the invitation of the SAB Ltd-Unesco Chair of Media and Democracy, to present and discuss initial research papers aimed at defining a common vision of journalism education on the African continent. The meeting was held against the backdrop of the bid by Rhodes University, under the auspices of the School of Journalism and Media Studies, to host the 2nd World Journalism Education Congress (WJEC).
- Full Text:
- Date Issued: 2010
Minimum spanning trees for valley and ridge characterization in digital elevation maps
- Bangay, Shaun D, de Bruyn, David, Glass, Kevin R
- Authors: Bangay, Shaun D , de Bruyn, David , Glass, Kevin R
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433247 , vital:72955 , https://doi.org/10.1145/1811158.1811171
- Description: Texture synthesis employs neighbourhood matching to generate appropriate new content. Terrain synthesis has the added constraint that new content must be geographically plausible. The profile recognition and polygon breaking algorithm (PPA) [Chang et al. 1998] provides a robust mechanism for characterizing terrain as systems of valley and ridge lines in digital elevation maps. We exploit this to create a terrain characterization metric that is robust, efficient to compute and is sensitive to terrain properties.
- Full Text:
- Date Issued: 2010
- Authors: Bangay, Shaun D , de Bruyn, David , Glass, Kevin R
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433247 , vital:72955 , https://doi.org/10.1145/1811158.1811171
- Description: Texture synthesis employs neighbourhood matching to generate appropriate new content. Terrain synthesis has the added constraint that new content must be geographically plausible. The profile recognition and polygon breaking algorithm (PPA) [Chang et al. 1998] provides a robust mechanism for characterizing terrain as systems of valley and ridge lines in digital elevation maps. We exploit this to create a terrain characterization metric that is robust, efficient to compute and is sensitive to terrain properties.
- Full Text:
- Date Issued: 2010
Two new species of Prosopistomatidae (Ephemeroptera) from South Africa and Swaziland
- Authors: Barber-James, Helen M
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452385 , vital:75124 , https://hdl.handle.net/10520/EJC32841
- Description: Three species of Prosopistoma Latreille, 1833 are currently described from Africa. The immature nymph of Prosopistoma deguernei Vayssière, 1893 was described from Senegal, and the nymph and winged stages of Prosopistoma africanum Gillies, 1954 are known from Tanzania. The southern African species Prosopistoma crassi Gillies, 1954, initially described as a nymph from KwaZulu-Natal, South Africa, has subsequently been collected in a number of South African rivers. Two further species from South Africa are described here, the nymph of Prosopistoma amanzamnyama sp. n., and the nymph and female subimago of Prosopistoma mccaffertyi sp. n.
- Full Text:
- Date Issued: 2010
- Authors: Barber-James, Helen M
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452385 , vital:75124 , https://hdl.handle.net/10520/EJC32841
- Description: Three species of Prosopistoma Latreille, 1833 are currently described from Africa. The immature nymph of Prosopistoma deguernei Vayssière, 1893 was described from Senegal, and the nymph and winged stages of Prosopistoma africanum Gillies, 1954 are known from Tanzania. The southern African species Prosopistoma crassi Gillies, 1954, initially described as a nymph from KwaZulu-Natal, South Africa, has subsequently been collected in a number of South African rivers. Two further species from South Africa are described here, the nymph of Prosopistoma amanzamnyama sp. n., and the nymph and female subimago of Prosopistoma mccaffertyi sp. n.
- Full Text:
- Date Issued: 2010
"Fit for purpose": towards tracking the quality of university education of entry-level journalists
- Authors: Berger, Guy
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159835 , vital:40348 , DOI: 10.1080/02560054.2005.9653329
- Description: Debate about the extent to which university education should serve industry is an important consideration for institutions of higher learning in a transforming South Africa, and particularly for those teaching would-be journalists. This issue can also be profitably analysed with reference to the current framework of the South African education authorities who argue that the quality of higher education institutions should be measured in terms of their “fit for purpose” to missions aligned to stakeholder interests in the transformation of the country as a whole. This criterion for quality assessment tends to focus on the educative processes within a university, but it can be argued that it ought to extend into the examination of the output consequences of journalism teaching. This would amount to not just fitness for purpose, but also achievement of purpose – and the latter including a creative and critical impact.
- Full Text:
- Date Issued: 2010
- Authors: Berger, Guy
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159835 , vital:40348 , DOI: 10.1080/02560054.2005.9653329
- Description: Debate about the extent to which university education should serve industry is an important consideration for institutions of higher learning in a transforming South Africa, and particularly for those teaching would-be journalists. This issue can also be profitably analysed with reference to the current framework of the South African education authorities who argue that the quality of higher education institutions should be measured in terms of their “fit for purpose” to missions aligned to stakeholder interests in the transformation of the country as a whole. This criterion for quality assessment tends to focus on the educative processes within a university, but it can be argued that it ought to extend into the examination of the output consequences of journalism teaching. This would amount to not just fitness for purpose, but also achievement of purpose – and the latter including a creative and critical impact.
- Full Text:
- Date Issued: 2010
Identifying annotations for adventure game generation from fiction text
- Berkland, Ross, Bangay, Shaun D
- Authors: Berkland, Ross , Bangay, Shaun D
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433366 , vital:72965 , https://doi.org/10.1145/1899503.1899506
- Description: Recent advancements in Text-to-Scene research have lead to the devel-opment of systems which automatically extract key concepts from the text of a fiction book and generate computer animated movies depicting the sto-ry. Extracting such annotations from raw fiction text is a laborious process and so in this work we evaluate appropriate candidates to serve as the basis for the required annotations for generating interactive virtual worlds. We val-idate our choice by generating adventure games: interactive virtual worlds which create a stylized representation of the environment described in the text, populate it with characters related to the story and define game goals related to the plot of the fiction story. Our prototype produces a fully playa-ble game, making use of an existing open-source game engine. The pro-cess is evaluated using user tests in which participants are asked to meas-ure the accuracy with which the game represents the events, characters and goals described in the story. The response indicates that the chosen an-notation set is sufficient to define a game that is a plausibly acceptable rep-resentation of the text.
- Full Text:
- Date Issued: 2010
- Authors: Berkland, Ross , Bangay, Shaun D
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433366 , vital:72965 , https://doi.org/10.1145/1899503.1899506
- Description: Recent advancements in Text-to-Scene research have lead to the devel-opment of systems which automatically extract key concepts from the text of a fiction book and generate computer animated movies depicting the sto-ry. Extracting such annotations from raw fiction text is a laborious process and so in this work we evaluate appropriate candidates to serve as the basis for the required annotations for generating interactive virtual worlds. We val-idate our choice by generating adventure games: interactive virtual worlds which create a stylized representation of the environment described in the text, populate it with characters related to the story and define game goals related to the plot of the fiction story. Our prototype produces a fully playa-ble game, making use of an existing open-source game engine. The pro-cess is evaluated using user tests in which participants are asked to meas-ure the accuracy with which the game represents the events, characters and goals described in the story. The response indicates that the chosen an-notation set is sufficient to define a game that is a plausibly acceptable rep-resentation of the text.
- Full Text:
- Date Issued: 2010