Photophysical properties of newly synthesized fluorinated zinc phthalocyanines in the presence of CdTe quantum dots and the accompanying energy transfer processes
- Erdoğmuş, Ali, Moeno, Sharon, Litwinski, Christian, Nyokong, Tebello
- Authors: Erdoğmuş, Ali , Moeno, Sharon , Litwinski, Christian , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262671 , vital:53543 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.12.014"
- Description: The photophysical properties of two newly synthesized phthalocyanines (Pcs) were studied in the presence and the absence of 3-mercaptopropionic acid (MPA) capped quantum dots (QDs). Energy transfer processes resulting from the combination of QDs and the Pcs: 4-(tetrakis-5-(trifluoromethyl)-2-mercaptopyridinephthalocyaninato)zinc(II) (TtfmMPyZnPc, 3) and 4-(tetrakis-5-(trifluoromethyl)-2-pyridyloxyphthalocyaninato) zinc(II) (TtfmPyZnPc, 4) were also studied. The photophysical properties of the Pcs in the presence of QDs were enhanced and Förster resonance energy transfer (FRET) was observed with the phthalocyanines used. The efficiency of FRET between the QDs and TtfmMPyZnPc and TtfmPyZnPc was found to be 0.31% and 0.45% in DMSO and 0.24% and 0.32% in pyridine, respectively. The triplet state quantum yields for TtfmMPyZnPc and TtfmPyZnPc were found to be 0.86 and 0.74 in DMSO and 0.83 and 0.76 in pyridine.
- Full Text:
- Date Issued: 2010
- Authors: Erdoğmuş, Ali , Moeno, Sharon , Litwinski, Christian , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262671 , vital:53543 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.12.014"
- Description: The photophysical properties of two newly synthesized phthalocyanines (Pcs) were studied in the presence and the absence of 3-mercaptopropionic acid (MPA) capped quantum dots (QDs). Energy transfer processes resulting from the combination of QDs and the Pcs: 4-(tetrakis-5-(trifluoromethyl)-2-mercaptopyridinephthalocyaninato)zinc(II) (TtfmMPyZnPc, 3) and 4-(tetrakis-5-(trifluoromethyl)-2-pyridyloxyphthalocyaninato) zinc(II) (TtfmPyZnPc, 4) were also studied. The photophysical properties of the Pcs in the presence of QDs were enhanced and Förster resonance energy transfer (FRET) was observed with the phthalocyanines used. The efficiency of FRET between the QDs and TtfmMPyZnPc and TtfmPyZnPc was found to be 0.31% and 0.45% in DMSO and 0.24% and 0.32% in pyridine, respectively. The triplet state quantum yields for TtfmMPyZnPc and TtfmPyZnPc were found to be 0.86 and 0.74 in DMSO and 0.83 and 0.76 in pyridine.
- Full Text:
- Date Issued: 2010
Applications of polymerized metal tetra-amino phthalocyanines towards hydrogen peroxide detection
- Mashazi, Philani N, Togo, Chumunorwa, Limson, Janice, Nyokong, Tebello
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
Factors affecting information technology implementation in the mobile telecommunications industry: a family business case
- Authors: De Jong, Piet
- Date: 2010
- Subjects: Mobile communication systems -- Technological innovations , Family-owned business enterprises -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8629 , http://hdl.handle.net/10948/1486 , Mobile communication systems -- Technological innovations , Family-owned business enterprises -- South Africa
- Description: This treatise investigates how information technology (I.T.) enables growth in a family business (the firm) in Port Elizabeth. The firm operates in the mobile telecommunications sector. The objective of the study is to gain a deeper understanding on why family businesses adopt information technology in their firm by means of a case study. The firm found its technology (or lack thereof) completely out-dated compared to the competition and customer demands. The future of the firm was in jeopardy. The study starts with a literature review of the following three topics which form part of the scope of the research: 1. Family businesses; 2. Influence of I.T. as a driver of growth in business; and 3. An introduction into the mobile telecommunications industry. Data are collected through structured interviews with family members involved in the business. The data are consequently linked to the theory and provides insight as to what the drivers are for I.T. adoption and the required core competencies or critical success factors of the firm. Although it might seem trivial for a small family business to adopt information technology, the research concludes that I.T. is critical for continuous growth and survival of this family business. Conversely due to a lack of internal skills the firm is heavily reliant upon outside consultants for advice, implementation and support. Recommendations which are of particular interest to family businesses in a similar environment are: • Embrace technology early, utilise I.T. solutions to grow and enhance current competitive advantage, do not see I.T. as a competitive advantage alone (Pavlou & Sawy, 2006); • If information expertise is not present within the company it is advisable to invest in that expertise through recruitment, training, partnership, or outsourcing; • Ensure software meets specification / is effective enough – this can be achieved by frequent releases cycles with small changes instead of infrequent release cycles with many big changes; • Engage the consultants in a partnership by i.e. providing a profit share – this will ensure that the consultants are committed to the cause and will also ensure that their involvement is also in their own best interest; • Choose local consultants who are easily accessible – build relationships and focus on trust; • Create lock-in (Amit & Zott, 2001), provide tools free-ofcharge for customers, this will make switching to competitor more difficult; • Automate as much as possible, enable standard work practices, routinize; • Be ready to adjust the organisational structure or relinquish control (Bruquea & Moyanob, 2007)
- Full Text:
- Date Issued: 2010
- Authors: De Jong, Piet
- Date: 2010
- Subjects: Mobile communication systems -- Technological innovations , Family-owned business enterprises -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8629 , http://hdl.handle.net/10948/1486 , Mobile communication systems -- Technological innovations , Family-owned business enterprises -- South Africa
- Description: This treatise investigates how information technology (I.T.) enables growth in a family business (the firm) in Port Elizabeth. The firm operates in the mobile telecommunications sector. The objective of the study is to gain a deeper understanding on why family businesses adopt information technology in their firm by means of a case study. The firm found its technology (or lack thereof) completely out-dated compared to the competition and customer demands. The future of the firm was in jeopardy. The study starts with a literature review of the following three topics which form part of the scope of the research: 1. Family businesses; 2. Influence of I.T. as a driver of growth in business; and 3. An introduction into the mobile telecommunications industry. Data are collected through structured interviews with family members involved in the business. The data are consequently linked to the theory and provides insight as to what the drivers are for I.T. adoption and the required core competencies or critical success factors of the firm. Although it might seem trivial for a small family business to adopt information technology, the research concludes that I.T. is critical for continuous growth and survival of this family business. Conversely due to a lack of internal skills the firm is heavily reliant upon outside consultants for advice, implementation and support. Recommendations which are of particular interest to family businesses in a similar environment are: • Embrace technology early, utilise I.T. solutions to grow and enhance current competitive advantage, do not see I.T. as a competitive advantage alone (Pavlou & Sawy, 2006); • If information expertise is not present within the company it is advisable to invest in that expertise through recruitment, training, partnership, or outsourcing; • Ensure software meets specification / is effective enough – this can be achieved by frequent releases cycles with small changes instead of infrequent release cycles with many big changes; • Engage the consultants in a partnership by i.e. providing a profit share – this will ensure that the consultants are committed to the cause and will also ensure that their involvement is also in their own best interest; • Choose local consultants who are easily accessible – build relationships and focus on trust; • Create lock-in (Amit & Zott, 2001), provide tools free-ofcharge for customers, this will make switching to competitor more difficult; • Automate as much as possible, enable standard work practices, routinize; • Be ready to adjust the organisational structure or relinquish control (Bruquea & Moyanob, 2007)
- Full Text:
- Date Issued: 2010
Chemical transformations and phytochemical studies of bioactive components from extracts of Rosmarinus officinalis L
- Authors: Okoh, Omobola Oluranti
- Date: 2010
- Subjects: Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11331 , http://hdl.handle.net/10353/354 , Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts.
- Full Text:
- Date Issued: 2010
- Authors: Okoh, Omobola Oluranti
- Date: 2010
- Subjects: Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11331 , http://hdl.handle.net/10353/354 , Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts.
- Full Text:
- Date Issued: 2010
Dynamic adaptive cost model for wireless Internet connectivity in African rural communities
- Authors: Sibanda, Khulumani
- Date: 2010
- Subjects: Internet , Community development -- South Africa -- Eastern Cape , Cost effectiveness , Wireless communication systems , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Computer Science)
- Identifier: vital:11389 , http://hdl.handle.net/10353/380 , Internet , Community development -- South Africa -- Eastern Cape , Cost effectiveness , Wireless communication systems , Rural development -- South Africa -- Eastern Cape
- Description: In today’s dynamic technological landscape, wireless communication networks have become an important part of economic development. The emergence of wireless technologies raises hopes to extend communication to remote areas that have not seen any tangible deployment to date. As developing nations pin their hopes to wireless technologies, cost models for wireless communication networks are becoming vital to support the emerging technologies. However, varying cost changes raise critical challenges to the estimation of both capital expenditure and operational expenditure. The network deployment process has numerous events that may cause adjustments to initially estimated project costs. These adjustments are necessary for a cost management plan and this plan includes monitoring cost performance and ensuring that only appropriate changes are made to the network project. The incidents that may cause cost changes can not be entirely predicted as their distribution tend to change dynamically from time to time. Estimating network deployment costs in such a dynamic environment necessitates cost models that can adapt to random occurrence of cost changes. Widely used cost models are usually performed by experienced personnel whose engineering experience is derived from deploying similar networks. In this approach experienced personnel add a certain percentage to the cost estimate to cater for contingency costs. Certainly such an approach depends on individual opinion, making it subjective and void of mathematical estimating relationships which are of paramount importance in ensuring that estimated deployment costs are sufficient to deal with cost uncertainties. We observe that existing approaches can only explore a limited solution space and hence can lead to cost overruns if implemented in dynamically cost changing environments. This thesis presents a wireless communication network deployment cost model that incorporates uncertainties into the final cost estimate. The model is adaptive to unpredictable cost changes since it allows adjustments of confidence levels when calculating contingency costs. This allows dynamically updating the cost changes without the cost model being reconstructed from scratch. We make use of the Poisson process in modeling the occurrence of incidents that are responsible for causing cost changes during network deployment. We also show that the occurrence of the incidents causing cost change are random and tend to follow the Poisson distribution. Using different levels of confidence we model various cost contingencies and make sensitivity analyses to identify the probability of cost overrun when given different contingencies. The dynamic adaptive cost model can be used either at the strategic level to understand the cost of a particular technique or at the operational level, as a way to show how Poisson process in network deployment can compare with engineering experience and other estimating techniques. We believe that the model is useful for remote areas where deployment costs are volatile and the distribution of incidents causing cost change to original cost estimates are diverse and dynamically changing. Further we expect that our research improves the knowledge base of information about the costs for rural communities to connect to the Internet, consequently providing useful input to future policy debates. This work is further poised to be a utility function to help those planning internet infrastructure deployments in least developed regions.
- Full Text:
- Date Issued: 2010
- Authors: Sibanda, Khulumani
- Date: 2010
- Subjects: Internet , Community development -- South Africa -- Eastern Cape , Cost effectiveness , Wireless communication systems , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Computer Science)
- Identifier: vital:11389 , http://hdl.handle.net/10353/380 , Internet , Community development -- South Africa -- Eastern Cape , Cost effectiveness , Wireless communication systems , Rural development -- South Africa -- Eastern Cape
- Description: In today’s dynamic technological landscape, wireless communication networks have become an important part of economic development. The emergence of wireless technologies raises hopes to extend communication to remote areas that have not seen any tangible deployment to date. As developing nations pin their hopes to wireless technologies, cost models for wireless communication networks are becoming vital to support the emerging technologies. However, varying cost changes raise critical challenges to the estimation of both capital expenditure and operational expenditure. The network deployment process has numerous events that may cause adjustments to initially estimated project costs. These adjustments are necessary for a cost management plan and this plan includes monitoring cost performance and ensuring that only appropriate changes are made to the network project. The incidents that may cause cost changes can not be entirely predicted as their distribution tend to change dynamically from time to time. Estimating network deployment costs in such a dynamic environment necessitates cost models that can adapt to random occurrence of cost changes. Widely used cost models are usually performed by experienced personnel whose engineering experience is derived from deploying similar networks. In this approach experienced personnel add a certain percentage to the cost estimate to cater for contingency costs. Certainly such an approach depends on individual opinion, making it subjective and void of mathematical estimating relationships which are of paramount importance in ensuring that estimated deployment costs are sufficient to deal with cost uncertainties. We observe that existing approaches can only explore a limited solution space and hence can lead to cost overruns if implemented in dynamically cost changing environments. This thesis presents a wireless communication network deployment cost model that incorporates uncertainties into the final cost estimate. The model is adaptive to unpredictable cost changes since it allows adjustments of confidence levels when calculating contingency costs. This allows dynamically updating the cost changes without the cost model being reconstructed from scratch. We make use of the Poisson process in modeling the occurrence of incidents that are responsible for causing cost changes during network deployment. We also show that the occurrence of the incidents causing cost change are random and tend to follow the Poisson distribution. Using different levels of confidence we model various cost contingencies and make sensitivity analyses to identify the probability of cost overrun when given different contingencies. The dynamic adaptive cost model can be used either at the strategic level to understand the cost of a particular technique or at the operational level, as a way to show how Poisson process in network deployment can compare with engineering experience and other estimating techniques. We believe that the model is useful for remote areas where deployment costs are volatile and the distribution of incidents causing cost change to original cost estimates are diverse and dynamically changing. Further we expect that our research improves the knowledge base of information about the costs for rural communities to connect to the Internet, consequently providing useful input to future policy debates. This work is further poised to be a utility function to help those planning internet infrastructure deployments in least developed regions.
- 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
Reactivity of Rhenium (iii) and Rhenium (V) with multidentate NN-and no-donor ligands
- Yumata, Nonzaliseko Christine
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
Quantification of greenhouse gas fluxes from soil in agricultural fields
- Authors: Nkongolo, Nsalambi Vakanda
- Date: 2010
- Subjects: Greenhouse gases -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10645 , http://hdl.handle.net/10948/1474 , Greenhouse gases -- Environmental aspects
- Description: Field studies were conducted at Lincoln University of Missouri (USA) and Hokkaido University (Japan) to: (i) study the relationships between greenhouse gases emissions and soil properties, (ii) assess the influence of agricultural practices on greenhouse gas fluxes and soil properties and (iii) improve the quantification of greenhouse gases from soil in agricultural fields using geospatial technologies. Results showed that besides soil temperature (T), soil thermal properties such as thermal conductivity (K), resistivity (R) and diffusivity (D) and soil pore spaces indices such as the pore tortuosity factor and the relative gas diffusion coefficient (Ds/Do) are controlling factors for greenhouse gases emissions. Soil thermal properties correlated with greenhouse gases emissions when soil temperature could not. The study has found that predicted Ds/Do and correlate with greenhouse gas fluxes even when the air-filled porosity and the total porosity from which they are predicted did not. We have also showed that Ds/Do and can be predicted quickly from routine measurements of soil water and air and existing diffusivity models found in the literature. Agricultural practices do seriously impact greenhouse gases emissions as showed by the effect of mechanized tillage operations on soil physical properties and greenhouse gas fluxes in a corn and soybean fields. In fact, our results showed that tractor compaction increased soil resistance to penetration, water, bulk density and pore tortuosity while reducing air-filled porosity, total pore space and the soil gas diffusion coefficient. Changes in soil properties resulted in increased CO2, NO and N2O emissions. Finally, our results also confirmed that greenhouse gas fluxes vary tremendously in space and time. As estimates of greenhouse gas emissions are influenced by the data processing approach, differences between the different calculation approaches leads to uncertainty. Thus, techniques for developing better estimates are needed. We have showed that Geographic Information Systems (GIS), Global Positioning System (GPS), computer mapping and geo-statistics are technologies that can be used to better understand systems containing large amounts of spatial and temporal variability. Our GIS-based approach for quantifying CO2, CH4 and N2O fluxes from soil in agricultural fields showed that estimating (extrapolating) total greenhouse gas fluxes using the “standard” approach – multiplying the average flux value by the total field area – results in biased predictions of field total greenhouse gases emissions. In contrast, the GIS-based approach we developed produces an interpolated map portraying the spatial distribution of gas fluxes across the field from point measurements and later process the interpolated map produced to determine flux zones. Furthermore, processing, classification and modeling enables the computation of field total fluxes as the sum of fluxes in different zones, therefore taking into account the spatial variability of greenhouse gas fluxes.
- Full Text:
- Date Issued: 2010
- Authors: Nkongolo, Nsalambi Vakanda
- Date: 2010
- Subjects: Greenhouse gases -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10645 , http://hdl.handle.net/10948/1474 , Greenhouse gases -- Environmental aspects
- Description: Field studies were conducted at Lincoln University of Missouri (USA) and Hokkaido University (Japan) to: (i) study the relationships between greenhouse gases emissions and soil properties, (ii) assess the influence of agricultural practices on greenhouse gas fluxes and soil properties and (iii) improve the quantification of greenhouse gases from soil in agricultural fields using geospatial technologies. Results showed that besides soil temperature (T), soil thermal properties such as thermal conductivity (K), resistivity (R) and diffusivity (D) and soil pore spaces indices such as the pore tortuosity factor and the relative gas diffusion coefficient (Ds/Do) are controlling factors for greenhouse gases emissions. Soil thermal properties correlated with greenhouse gases emissions when soil temperature could not. The study has found that predicted Ds/Do and correlate with greenhouse gas fluxes even when the air-filled porosity and the total porosity from which they are predicted did not. We have also showed that Ds/Do and can be predicted quickly from routine measurements of soil water and air and existing diffusivity models found in the literature. Agricultural practices do seriously impact greenhouse gases emissions as showed by the effect of mechanized tillage operations on soil physical properties and greenhouse gas fluxes in a corn and soybean fields. In fact, our results showed that tractor compaction increased soil resistance to penetration, water, bulk density and pore tortuosity while reducing air-filled porosity, total pore space and the soil gas diffusion coefficient. Changes in soil properties resulted in increased CO2, NO and N2O emissions. Finally, our results also confirmed that greenhouse gas fluxes vary tremendously in space and time. As estimates of greenhouse gas emissions are influenced by the data processing approach, differences between the different calculation approaches leads to uncertainty. Thus, techniques for developing better estimates are needed. We have showed that Geographic Information Systems (GIS), Global Positioning System (GPS), computer mapping and geo-statistics are technologies that can be used to better understand systems containing large amounts of spatial and temporal variability. Our GIS-based approach for quantifying CO2, CH4 and N2O fluxes from soil in agricultural fields showed that estimating (extrapolating) total greenhouse gas fluxes using the “standard” approach – multiplying the average flux value by the total field area – results in biased predictions of field total greenhouse gases emissions. In contrast, the GIS-based approach we developed produces an interpolated map portraying the spatial distribution of gas fluxes across the field from point measurements and later process the interpolated map produced to determine flux zones. Furthermore, processing, classification and modeling enables the computation of field total fluxes as the sum of fluxes in different zones, therefore taking into account the spatial variability of greenhouse gas fluxes.
- Full Text:
- Date Issued: 2010
The evaluation of environmental reporting by publicly listed South African banks
- Authors: Oduro-Kwateng, George
- Date: 2010
- Subjects: Environmental reporting -- South Africa Banks and banking -- South Africa Social responsibility in banking -- South Africa Social responsibility of business -- South Africa Environmental protection -- South Africa Environmental economics -- South Africa Economic development -- South Africa -- Environmental aspects Environmental management -- South Africa Climatic changes -- South Africa Coalition for Environmentally Responsible Economies Global Reporting Initiative Standard Bank Limited Nedbank ABSA Bank
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:740 , http://hdl.handle.net/10962/d1003860
- Description: Recently, bankers have come to realise that banking operations, especially corporate lending, affect and are affected by the natural environment and that consequently, the banks might have an important role to play in helping to raise environmental standards. Although the environment presents significant risks to banks, in particular environmental credit risk, it also perhaps presents profitable opportunities. Stricter environmental regulations have forced companies to invest in environmentally friendly technologies and pollution control measures and in tum generated lending opportunities for bankers. This research examines the corporate practices of three of the four dominant banks in South Africa with respect to the environment, focusing on issues of climate change and environmental risk management by way of reporting and disclosure to all stakeholders. The emphasis on environmental reporting by South African banks has been reinforced by the latest release of the King III Report on Corporate Governance in South Africa. Global governance requires that the triple-bottom line should be applied in all corporate undertakings due to globalisation and trade liberalisation; however, the banking sector has responded poorly to the clarion call. The false view that the banks have no significant relationship with environmental degradation is being disproved. Environmental management is a huge and massive reconstruction of what has gone wrong with nature by human influence. The South African banks have had to face with the challenging tasks of reporting on the direct and mostly the indirect impacts of their environmental activities. Based on the three sampled banks which incidentally had greater percentages of the market capitalizations, the banks have fairly performed in environmental reporting. For example, Standard Bank (SA) Ltd has just signed the Equator Principles in 2007 implying corporate lending was done in 2007 without any respect to environmental impact assessments by corporate borrowers. Consequently, environmental reporting was not done to facilitate informed decision-making by stakeholders mostly shareholders and the communities where borrowers tun businesses. The objective of this research study is to investigate the extent and quantity of/voluntary environmental disclosures in the annual and sustainability reports of the banks listed on Johannesburg Stock Exchange. The periods examined were those subsequent to the release of the Exposure Draft Coalition for Environmentally Responsible Economies (CERES) Global Reporting Initiatives (GRI) issued in 1999. Using content analysis to focus on the environmental aspects, the research study compared three annual reports and three sustainability reports of 2007 year for the three sampled banks in order to evaluate reporting practices in the period surrounding this intervention. The results suggest a trend to triple bottom-line reporting and the extent and quantity of environmental information, albeit in specific categories.
- Full Text:
- Date Issued: 2010
- Authors: Oduro-Kwateng, George
- Date: 2010
- Subjects: Environmental reporting -- South Africa Banks and banking -- South Africa Social responsibility in banking -- South Africa Social responsibility of business -- South Africa Environmental protection -- South Africa Environmental economics -- South Africa Economic development -- South Africa -- Environmental aspects Environmental management -- South Africa Climatic changes -- South Africa Coalition for Environmentally Responsible Economies Global Reporting Initiative Standard Bank Limited Nedbank ABSA Bank
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:740 , http://hdl.handle.net/10962/d1003860
- Description: Recently, bankers have come to realise that banking operations, especially corporate lending, affect and are affected by the natural environment and that consequently, the banks might have an important role to play in helping to raise environmental standards. Although the environment presents significant risks to banks, in particular environmental credit risk, it also perhaps presents profitable opportunities. Stricter environmental regulations have forced companies to invest in environmentally friendly technologies and pollution control measures and in tum generated lending opportunities for bankers. This research examines the corporate practices of three of the four dominant banks in South Africa with respect to the environment, focusing on issues of climate change and environmental risk management by way of reporting and disclosure to all stakeholders. The emphasis on environmental reporting by South African banks has been reinforced by the latest release of the King III Report on Corporate Governance in South Africa. Global governance requires that the triple-bottom line should be applied in all corporate undertakings due to globalisation and trade liberalisation; however, the banking sector has responded poorly to the clarion call. The false view that the banks have no significant relationship with environmental degradation is being disproved. Environmental management is a huge and massive reconstruction of what has gone wrong with nature by human influence. The South African banks have had to face with the challenging tasks of reporting on the direct and mostly the indirect impacts of their environmental activities. Based on the three sampled banks which incidentally had greater percentages of the market capitalizations, the banks have fairly performed in environmental reporting. For example, Standard Bank (SA) Ltd has just signed the Equator Principles in 2007 implying corporate lending was done in 2007 without any respect to environmental impact assessments by corporate borrowers. Consequently, environmental reporting was not done to facilitate informed decision-making by stakeholders mostly shareholders and the communities where borrowers tun businesses. The objective of this research study is to investigate the extent and quantity of/voluntary environmental disclosures in the annual and sustainability reports of the banks listed on Johannesburg Stock Exchange. The periods examined were those subsequent to the release of the Exposure Draft Coalition for Environmentally Responsible Economies (CERES) Global Reporting Initiatives (GRI) issued in 1999. Using content analysis to focus on the environmental aspects, the research study compared three annual reports and three sustainability reports of 2007 year for the three sampled banks in order to evaluate reporting practices in the period surrounding this intervention. The results suggest a trend to triple bottom-line reporting and the extent and quantity of environmental information, albeit in specific categories.
- Full Text:
- Date Issued: 2010
Histological validation of gonadal macroscopic staging criteria for Labeo cylindricus (Pisces: Cyprinidae)
- Booth, Anthony J, Weyl, Olaf L F
- Authors: Booth, Anthony J , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124593 , vital:35634 , https://doi.org/10.1080/15627020.2000.11657094
- Description: Histological examination of gametogenesis revealed that the current staging criteria used to assess gonadal recrudescence of the redeye labeo, Labeo cylindricus, were adequate. Gametogenesis was qualitatively similar to that of freshwater teleosts with a clearly defined seasonal reproductive cycle. L. cylindricus undergoes seasonal gross morphological and cytological gonadal changes with previtellogenesis dominating during the winter, vitellogenic development during spring and summer culminating in large-scale spawning at the end of summer. Post-spawning mass atresia of oocytes was evident in autumn. The histological data presented support macroscopical evidence that L. cylindricus is a synchronous iteroparous spawner, reproducing over a short period each year throughout its life-span.
- Full Text:
- Date Issued: 2010
- Authors: Booth, Anthony J , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124593 , vital:35634 , https://doi.org/10.1080/15627020.2000.11657094
- Description: Histological examination of gametogenesis revealed that the current staging criteria used to assess gonadal recrudescence of the redeye labeo, Labeo cylindricus, were adequate. Gametogenesis was qualitatively similar to that of freshwater teleosts with a clearly defined seasonal reproductive cycle. L. cylindricus undergoes seasonal gross morphological and cytological gonadal changes with previtellogenesis dominating during the winter, vitellogenic development during spring and summer culminating in large-scale spawning at the end of summer. Post-spawning mass atresia of oocytes was evident in autumn. The histological data presented support macroscopical evidence that L. cylindricus is a synchronous iteroparous spawner, reproducing over a short period each year throughout its life-span.
- Full Text:
- Date Issued: 2010
Cultivation of medicinal plants as a tool for biodiversity conservation and poverty alleviation in the Amatola region, South Africa:
- Wiersum, K Freerk, Dold, Anthony P, Husselman, Madeleen, Cocks, Michelle L
- Authors: Wiersum, K Freerk , Dold, Anthony P , Husselman, Madeleen , Cocks, Michelle L
- Date: 2010
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141489 , vital:37979 , ISBN 9781402054488 , https://library.wur.nl/ojs/index.php/frontis/issue/view/232
- Description: This paper describes the assumptions and results of a study to assess whether cultivation of medicinal plants can serve as a tool for combined biodiversity conservation and poverty alleviation. The study was carried out in the Amatola region of Eastern Cape, South Africa, where sustained beliefs in medicinal plant use, also under non-traditional conditions, has resulted in an increase in commercial demands. It was based on the assumption of poverty alleviation not only referring to an increase in income and labour, but also an increase in social capital and human dignity. The study assessed the local perceptions of the use and cultivation of medicinal plants and the need for conservation of these plants, as well as the features of already ongoing cultivation practices and options for increased cultivation. It consisted of participatory assessments in three villages involving around 250 persons and participatory trials with 14 rural women selling medicinal plants on urban markets. The study indicated that the growing demand for medicinal plants is related to the great cultural significance attached to medicinal plants.
- Full Text:
- Date Issued: 2010
- Authors: Wiersum, K Freerk , Dold, Anthony P , Husselman, Madeleen , Cocks, Michelle L
- Date: 2010
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/141489 , vital:37979 , ISBN 9781402054488 , https://library.wur.nl/ojs/index.php/frontis/issue/view/232
- Description: This paper describes the assumptions and results of a study to assess whether cultivation of medicinal plants can serve as a tool for combined biodiversity conservation and poverty alleviation. The study was carried out in the Amatola region of Eastern Cape, South Africa, where sustained beliefs in medicinal plant use, also under non-traditional conditions, has resulted in an increase in commercial demands. It was based on the assumption of poverty alleviation not only referring to an increase in income and labour, but also an increase in social capital and human dignity. The study assessed the local perceptions of the use and cultivation of medicinal plants and the need for conservation of these plants, as well as the features of already ongoing cultivation practices and options for increased cultivation. It consisted of participatory assessments in three villages involving around 250 persons and participatory trials with 14 rural women selling medicinal plants on urban markets. The study indicated that the growing demand for medicinal plants is related to the great cultural significance attached to medicinal plants.
- Full Text:
- Date Issued: 2010
A risk mitigation tool for merchant selection
- Schutte, Philippus Jacobus Wilhelmus
- Authors: Schutte, Philippus Jacobus Wilhelmus
- Date: 2010
- Subjects: Financial rsik management -- South Africa , Credit -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8650 , http://hdl.handle.net/10948/1382 , Financial rsik management -- South Africa , Credit -- Management
- Description: Organisations or individuals that lend money (banks and micro lenders) or that sell goods on credit (retailers) are classified as credit providers. The debtor enters into a contractual agreement with a credit provider, or creditor, with the obligation to repay the loan amount, fees and interest according to a predetermined schedule. The contractual agreement, also known as a credit agreement, is as a general rule very complex. Legislation protecting debtors in various ways is an international phenomenon. In South Africa, the National Credit Act, Act 34 of 2005 (NCA) was enacted in 2005. The NCA changed the playing field for credit providers participating in the South African consumer credit market to a great extent. Consumer lending is the sleeping giant of the financial sector. The key to successfully unlock this enormous market is the credit provider's ability to accurately assess the creditworthiness of a potential customer during the customer acquisition phase. The creditworthiness of the customer is related to the risk of default, i.e. a debtor's non-payment of debt in terms of the credit agreement. The risk of default is also known as credit risk. Real People Investment Holdings (Pty) Ltd (RPIH) classifies credit risk as the single largest risk the Group is exposed to. They recognise that the intelligent and responsible management of credit risk makes it the Group's largest profit driver. Credit risk scorecards are excellent decision aids during the customer acquisition phase. The characteristics and behaviour of merchants submitting credit applications to RPIH for assessment have a definite impact on the credit risk of the Group. The merchant plays a pivotal role in the debtor-creditor-supplier business model. The merchant influences the customer's sales experience and subsequent level of satisfaction with the transaction. A satisfied customer constitutes a lower level of credit risk for the creditor, in this case RPIH. The research is conducted with a positivistic paradigm. The cross-sectional study approach is used. The merchant is the unit of analysis. A sample of 77 merchants is selected from the population of 244 merchants who submitted credit applications to RPIH during the observation period. Questionnaires are used as the data collection method in this research project. The predictive ability of fourteen merchant related characteristics are demonstrated through this empirical study.
- Full Text:
- Date Issued: 2010
- Authors: Schutte, Philippus Jacobus Wilhelmus
- Date: 2010
- Subjects: Financial rsik management -- South Africa , Credit -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8650 , http://hdl.handle.net/10948/1382 , Financial rsik management -- South Africa , Credit -- Management
- Description: Organisations or individuals that lend money (banks and micro lenders) or that sell goods on credit (retailers) are classified as credit providers. The debtor enters into a contractual agreement with a credit provider, or creditor, with the obligation to repay the loan amount, fees and interest according to a predetermined schedule. The contractual agreement, also known as a credit agreement, is as a general rule very complex. Legislation protecting debtors in various ways is an international phenomenon. In South Africa, the National Credit Act, Act 34 of 2005 (NCA) was enacted in 2005. The NCA changed the playing field for credit providers participating in the South African consumer credit market to a great extent. Consumer lending is the sleeping giant of the financial sector. The key to successfully unlock this enormous market is the credit provider's ability to accurately assess the creditworthiness of a potential customer during the customer acquisition phase. The creditworthiness of the customer is related to the risk of default, i.e. a debtor's non-payment of debt in terms of the credit agreement. The risk of default is also known as credit risk. Real People Investment Holdings (Pty) Ltd (RPIH) classifies credit risk as the single largest risk the Group is exposed to. They recognise that the intelligent and responsible management of credit risk makes it the Group's largest profit driver. Credit risk scorecards are excellent decision aids during the customer acquisition phase. The characteristics and behaviour of merchants submitting credit applications to RPIH for assessment have a definite impact on the credit risk of the Group. The merchant plays a pivotal role in the debtor-creditor-supplier business model. The merchant influences the customer's sales experience and subsequent level of satisfaction with the transaction. A satisfied customer constitutes a lower level of credit risk for the creditor, in this case RPIH. The research is conducted with a positivistic paradigm. The cross-sectional study approach is used. The merchant is the unit of analysis. A sample of 77 merchants is selected from the population of 244 merchants who submitted credit applications to RPIH during the observation period. Questionnaires are used as the data collection method in this research project. The predictive ability of fourteen merchant related characteristics are demonstrated through this empirical study.
- Full Text:
- Date Issued: 2010
Integrated teaching strategies model for improved scientific literacy in second-language learners
- Villanueva, Mary Grace Flores
- Authors: Villanueva, Mary Grace Flores
- Date: 2010
- Subjects: Science -- Study and teaching (Elementary) -- South Africa , Science -- South Africa -- Methodology , Science -- Curricula
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9514 , http://hdl.handle.net/10948/1107 , Science -- Study and teaching (Elementary) -- South Africa , Science -- South Africa -- Methodology , Science -- Curricula
- Description: The importance of a scientifically literate society is currently acknowledged both internationally and South Africa. The notion of scientific literacy in South Africa has emerged largely due to the government’s recognition of the role that science and technology plays in economic growth, employment creation, social redress and social development. However, in light of South Africa’s learner performance on international and national assessments such as TIMMS (2003) and PIRLS (2006), as well as the problems of teaching and learning in a second language, there appears to be a primary and pressing need to develop learners’ fundamental sense of scientific literacy (Norris & Phillips, 2003). Expanding learners’ ability to read, write and communicate in science may provide the necessary framework for engaging learners in the critical principles and foundations of the scientific endeavour (Hand, Prain, & Yore, 2001). As such, this study focuses on equipping and training grade six and seven science teachers to develop scientifically literate learners via professional development workshops with a strategy that supports reading, writing, talking and conducting (‘doing’) science through scientific investigations. The typology of triangulation and the mixed method research approach was supported by a fully mixed, concurrent, and equal status design (Leech & Onwuegbuzi, 2007). Quantitative data were collected from the baseline and post-intervention testing of learners’ problem solving skills, as well as their literacy skills in English and isiXhosa. Qualitative measures were generated through classroom observations, teacher interviews and learners’ science notebooks. The study was conducted in two different milieus in the Eastern Cape, South Africa. The first setting, in the rural area of Tyumie Valley near the Hogsback Mountains, was comprised of a sample of grade six and seven (multi-grade classrooms) teachers (n=7) and learners (n=168) from five experimental schools and two comparison schools. The second setting, in the urban townships area east of Port Elizabeth, was comprised of a sample of grade six teachers (n=8) and learners (n=675) from six experimental schools and two comparison schools. Mean differences between the experimental and the comparison groups were computed for the Raven’s Standard Progressive Matrices (RSPM) and the literacy tests, and the data generated were treated with an Analysis of Covariance (ANCOVA). The data suggest that the scientific literacy strategy improved the experimental learners’ problem solving skills. Both experimental groups demonstrated greater gains than that of the comparison schools. However, statistically significant improvements were only detected in Port Elizabeth. Improvements in learners’ literacy skills in isiXhosa and English varied according to each milieu. While the teachers initially identified challenges to learners’ reading and writing abilities, the analysis of learners’ science notebooks suggested that they used writings to support their investigations. Some teachers cited difficulties with certain aspects of the model, such as problems with developing an investigable question and argumentation, yet overall, teachers found the strategy useful for developing learners’ language skills, as well for strengthening their pedagogical practices in science. Teachers’ gradual improvements in the use of the model suggest that they were able to use the scientific literacy strategy to support the cognitive and linguistic development of second-language learners.
- Full Text:
- Date Issued: 2010
- Authors: Villanueva, Mary Grace Flores
- Date: 2010
- Subjects: Science -- Study and teaching (Elementary) -- South Africa , Science -- South Africa -- Methodology , Science -- Curricula
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9514 , http://hdl.handle.net/10948/1107 , Science -- Study and teaching (Elementary) -- South Africa , Science -- South Africa -- Methodology , Science -- Curricula
- Description: The importance of a scientifically literate society is currently acknowledged both internationally and South Africa. The notion of scientific literacy in South Africa has emerged largely due to the government’s recognition of the role that science and technology plays in economic growth, employment creation, social redress and social development. However, in light of South Africa’s learner performance on international and national assessments such as TIMMS (2003) and PIRLS (2006), as well as the problems of teaching and learning in a second language, there appears to be a primary and pressing need to develop learners’ fundamental sense of scientific literacy (Norris & Phillips, 2003). Expanding learners’ ability to read, write and communicate in science may provide the necessary framework for engaging learners in the critical principles and foundations of the scientific endeavour (Hand, Prain, & Yore, 2001). As such, this study focuses on equipping and training grade six and seven science teachers to develop scientifically literate learners via professional development workshops with a strategy that supports reading, writing, talking and conducting (‘doing’) science through scientific investigations. The typology of triangulation and the mixed method research approach was supported by a fully mixed, concurrent, and equal status design (Leech & Onwuegbuzi, 2007). Quantitative data were collected from the baseline and post-intervention testing of learners’ problem solving skills, as well as their literacy skills in English and isiXhosa. Qualitative measures were generated through classroom observations, teacher interviews and learners’ science notebooks. The study was conducted in two different milieus in the Eastern Cape, South Africa. The first setting, in the rural area of Tyumie Valley near the Hogsback Mountains, was comprised of a sample of grade six and seven (multi-grade classrooms) teachers (n=7) and learners (n=168) from five experimental schools and two comparison schools. The second setting, in the urban townships area east of Port Elizabeth, was comprised of a sample of grade six teachers (n=8) and learners (n=675) from six experimental schools and two comparison schools. Mean differences between the experimental and the comparison groups were computed for the Raven’s Standard Progressive Matrices (RSPM) and the literacy tests, and the data generated were treated with an Analysis of Covariance (ANCOVA). The data suggest that the scientific literacy strategy improved the experimental learners’ problem solving skills. Both experimental groups demonstrated greater gains than that of the comparison schools. However, statistically significant improvements were only detected in Port Elizabeth. Improvements in learners’ literacy skills in isiXhosa and English varied according to each milieu. While the teachers initially identified challenges to learners’ reading and writing abilities, the analysis of learners’ science notebooks suggested that they used writings to support their investigations. Some teachers cited difficulties with certain aspects of the model, such as problems with developing an investigable question and argumentation, yet overall, teachers found the strategy useful for developing learners’ language skills, as well for strengthening their pedagogical practices in science. Teachers’ gradual improvements in the use of the model suggest that they were able to use the scientific literacy strategy to support the cognitive and linguistic development of second-language learners.
- Full Text:
- Date Issued: 2010
Beta-N-methylamino-L-alanine in South African fresh water cyanobacteria : incidence, prevalence, ecotoxicological considerations and human exposure risk
- Authors: Esterhuizen-Londt, Maranda
- Date: 2010
- Subjects: Cyanobacteria , Bioaccumulation , Chromatographic analysis , Neurotoxic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10306 , http://hdl.handle.net/10948/1473 , Cyanobacteria , Bioaccumulation , Chromatographic analysis , Neurotoxic agents
- Description: β-N-methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid associated with human neurodegenerative disease. Due to the cosmopolitan nature of cyanobacteria, detection of BMAA in cyanobacteria has caused concerns about human exposure risk. This study was therefore based on the hypothesis that BMAA poses a health risk to humans either by direct ingestion or by indirect exposure to BMAA from a cyanobacterial source via a freshwater food chain. A validated gas chromatography-mass spectrometry (GC-MS) BMAA analysis method and a confirmatory liquid chromatography-mass spectrometry (LC-MS) method, with improved sensitivity, were developed in addition to a LC-MS/MS method for analyte confirmation. These methods were used to quantify BMAA in South African cyanobacteria, isolated from various potable water reservoirs. The majority of the isolates tested, contained BMAA. Possible human exposure by direct consumption of BMAA released from cyanobacterial blooms was investigated by the development of a robust solid phase extraction (SPE) method used for BMAA concentration and quantification in raw and treated tap water. Despite the use of the SPE method that facilitated the concentration of BMAA from large quantities of water, no free dissolved BMAA was detected in raw or processed fresh water. The fate of exogenous BMAA was therefore investigated firstly by evaluating the efficacy of standard water treatment processes employed in South Africa and secondly by investigating the possibility of BMAA bioaccumulation and biomagnification in aquatic food chains. Standard water treatment processes proved highly efficient at removing free dissolved BMAA, explaining the absence of BMAA in treated tap water. However, the cause of the BMAA absence in raw potable water remained unknown. Uptake of BMAA by model aquatic organisms was investigated in controlled experiments. BMAA uptake was documented in both Ceratophyllum demersum and Daphnia magna, however, BMAA-protein association and biomagnification were not observed in D. magna. BMAA had an inhibitory effect on the oxidative stress enzyme acitivties of both organisms tested (as well as human S9 extracts), resulting in accumulation of detrimental reactive oxygen species (ROS) in the cells. Exposure of crop plants to BMAA in controlled experiments resulted in BMAA uptake, protein association, and subsequent inhibition of the antioxidative enzyme activities. However, BMAA was detected in neither free nor protein-associated form in natural crop plants irrigated with known BMAA-containing bloom water. Post-mortem liver samples of Clarias gariepinus (Catfish) and Crocodylus niloticus (Crocodile), from a natural fresh water ecosystem that experienced frequent cyanobacterial blooms, contained both free and protein-associated BMAA. Higher BMAA concentrations were found in crocodile liver samples compared to fish liver samples, strongly suggesting biomagnification from one trophic level to the next. BMAA concentrations corresponded to crocodile age. This is the first report of bioaccumulation and biomagnification in two trophic levels in a fresh water ecosystem. These findings strongly suggest possible human exposure via aquatic food chains of cyanobacterial origin. Direct BMAA exposure via drinking water is not plausible due to the efficiency of standard water treatment processes to remove BMAA. The use of raw water for agricultural and recreational use, however, remains a problem. The development of management strategies as well as daily tolerable levels for BMAA is urgently required.
- Full Text:
- Date Issued: 2010
- Authors: Esterhuizen-Londt, Maranda
- Date: 2010
- Subjects: Cyanobacteria , Bioaccumulation , Chromatographic analysis , Neurotoxic agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10306 , http://hdl.handle.net/10948/1473 , Cyanobacteria , Bioaccumulation , Chromatographic analysis , Neurotoxic agents
- Description: β-N-methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid associated with human neurodegenerative disease. Due to the cosmopolitan nature of cyanobacteria, detection of BMAA in cyanobacteria has caused concerns about human exposure risk. This study was therefore based on the hypothesis that BMAA poses a health risk to humans either by direct ingestion or by indirect exposure to BMAA from a cyanobacterial source via a freshwater food chain. A validated gas chromatography-mass spectrometry (GC-MS) BMAA analysis method and a confirmatory liquid chromatography-mass spectrometry (LC-MS) method, with improved sensitivity, were developed in addition to a LC-MS/MS method for analyte confirmation. These methods were used to quantify BMAA in South African cyanobacteria, isolated from various potable water reservoirs. The majority of the isolates tested, contained BMAA. Possible human exposure by direct consumption of BMAA released from cyanobacterial blooms was investigated by the development of a robust solid phase extraction (SPE) method used for BMAA concentration and quantification in raw and treated tap water. Despite the use of the SPE method that facilitated the concentration of BMAA from large quantities of water, no free dissolved BMAA was detected in raw or processed fresh water. The fate of exogenous BMAA was therefore investigated firstly by evaluating the efficacy of standard water treatment processes employed in South Africa and secondly by investigating the possibility of BMAA bioaccumulation and biomagnification in aquatic food chains. Standard water treatment processes proved highly efficient at removing free dissolved BMAA, explaining the absence of BMAA in treated tap water. However, the cause of the BMAA absence in raw potable water remained unknown. Uptake of BMAA by model aquatic organisms was investigated in controlled experiments. BMAA uptake was documented in both Ceratophyllum demersum and Daphnia magna, however, BMAA-protein association and biomagnification were not observed in D. magna. BMAA had an inhibitory effect on the oxidative stress enzyme acitivties of both organisms tested (as well as human S9 extracts), resulting in accumulation of detrimental reactive oxygen species (ROS) in the cells. Exposure of crop plants to BMAA in controlled experiments resulted in BMAA uptake, protein association, and subsequent inhibition of the antioxidative enzyme activities. However, BMAA was detected in neither free nor protein-associated form in natural crop plants irrigated with known BMAA-containing bloom water. Post-mortem liver samples of Clarias gariepinus (Catfish) and Crocodylus niloticus (Crocodile), from a natural fresh water ecosystem that experienced frequent cyanobacterial blooms, contained both free and protein-associated BMAA. Higher BMAA concentrations were found in crocodile liver samples compared to fish liver samples, strongly suggesting biomagnification from one trophic level to the next. BMAA concentrations corresponded to crocodile age. This is the first report of bioaccumulation and biomagnification in two trophic levels in a fresh water ecosystem. These findings strongly suggest possible human exposure via aquatic food chains of cyanobacterial origin. Direct BMAA exposure via drinking water is not plausible due to the efficiency of standard water treatment processes to remove BMAA. The use of raw water for agricultural and recreational use, however, remains a problem. The development of management strategies as well as daily tolerable levels for BMAA is urgently required.
- Full Text:
- Date Issued: 2010
Quality assessment of information systems in SMEs: a study of Eldoret Town in Kenya
- Authors: Ndiege, Joshua Rumo Arongo
- Date: 2010
- Subjects: Small business -- Kenya , Financial institutions -- Kenya , Small business -- Kenya -- Data processing , Information technology -- Kenya -- Evaluation
- Language: English
- Type: Thesis , Masters , MCom (Information Systems)
- Identifier: vital:11132 , http://hdl.handle.net/10353/d1000973 , Small business -- Kenya , Financial institutions -- Kenya , Small business -- Kenya -- Data processing , Information technology -- Kenya -- Evaluation
- Full Text: false
- Date Issued: 2010
- Authors: Ndiege, Joshua Rumo Arongo
- Date: 2010
- Subjects: Small business -- Kenya , Financial institutions -- Kenya , Small business -- Kenya -- Data processing , Information technology -- Kenya -- Evaluation
- Language: English
- Type: Thesis , Masters , MCom (Information Systems)
- Identifier: vital:11132 , http://hdl.handle.net/10353/d1000973 , Small business -- Kenya , Financial institutions -- Kenya , Small business -- Kenya -- Data processing , Information technology -- Kenya -- Evaluation
- Full Text: false
- Date Issued: 2010
Semi-submersible rigs: a vector transporting entire marine communities around the world
- Wanless, Ross M, Scott, Sue, Sauer, Warwick H H, Andrew, Timothy G, Glass, James P, Godfrey, Brian, Griffiths, Charles, Yeld, Eleanor
- Authors: Wanless, Ross M , Scott, Sue , Sauer, Warwick H H , Andrew, Timothy G , Glass, James P , Godfrey, Brian , Griffiths, Charles , Yeld, Eleanor
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126920 , vital:35935 , https://doi.10.1007/s10530-009-9666-2
- Description: A virtually intact subtropical reef community (14 phyla, 40 families and 62 non-native taxa) was associated with a rig under tow from Brazil that became stranded on the remote island of Tristan da Cunha. This exposes rigs as a significant vector spreading alien marine organisms, and includes the first records of free-swimming marine finfish populations becoming established after unintentional movement. With relatively trivial effort, a pre-tow clean would have obviated the need to salvage and dispose of the rig (undertaken largely to address concerns about invasive species), at a cost of *US$20 million. Our findings show that towing biofouled structures across biogeographic boundaries present unexcelled opportunities for invasion to a wide diversity of marine species. Better control and management of this vector is required urgently. Simultaneous, unintentional introductions of viable populations of multiple marine organisms are rare events, and we develop a basic framework for rapid assessment of invasion risks.
- Full Text:
- Date Issued: 2010
- Authors: Wanless, Ross M , Scott, Sue , Sauer, Warwick H H , Andrew, Timothy G , Glass, James P , Godfrey, Brian , Griffiths, Charles , Yeld, Eleanor
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126920 , vital:35935 , https://doi.10.1007/s10530-009-9666-2
- Description: A virtually intact subtropical reef community (14 phyla, 40 families and 62 non-native taxa) was associated with a rig under tow from Brazil that became stranded on the remote island of Tristan da Cunha. This exposes rigs as a significant vector spreading alien marine organisms, and includes the first records of free-swimming marine finfish populations becoming established after unintentional movement. With relatively trivial effort, a pre-tow clean would have obviated the need to salvage and dispose of the rig (undertaken largely to address concerns about invasive species), at a cost of *US$20 million. Our findings show that towing biofouled structures across biogeographic boundaries present unexcelled opportunities for invasion to a wide diversity of marine species. Better control and management of this vector is required urgently. Simultaneous, unintentional introductions of viable populations of multiple marine organisms are rare events, and we develop a basic framework for rapid assessment of invasion risks.
- Full Text:
- Date Issued: 2010
Integer optimisation for the selection of a fantasy league cricket team
- Authors: Brettenny, Warren James
- Date: 2010
- Subjects: Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10565 , http://hdl.handle.net/10948/1230 , Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Description: Sports fans often scrutinise the team selection strategies employed by their favourite team's coach or selection panel. Many of these fans believe that they can perform the selection process far better than those tasked with the responsibility. Fantasy leagues, provide a platform for fans to test their hand at this selection procedure. Twenty20 cricket is a new and exciting form of cricket and has become very popular in recent years. This research focuses on bringing these concepts together by proposing a binary integer program to determine a team selection strategy for fantasy league cricket. This is done in a Twenty20 setting. The approach used in this study focuses on evaluating the effectiveness of previously developed performance measures in a fantasy league setting. Adjustments to these measures are made and new measures are proposed. These measures are then used to select a fantasy league team using a prospective approach. This is done to provide fantasy league participants with a mathematical procedure for fantasy league team selection.
- Full Text:
- Date Issued: 2010
- Authors: Brettenny, Warren James
- Date: 2010
- Subjects: Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10565 , http://hdl.handle.net/10948/1230 , Sports -- Research -- Methodology , Teamwork (Sports) , Cricket players
- Description: Sports fans often scrutinise the team selection strategies employed by their favourite team's coach or selection panel. Many of these fans believe that they can perform the selection process far better than those tasked with the responsibility. Fantasy leagues, provide a platform for fans to test their hand at this selection procedure. Twenty20 cricket is a new and exciting form of cricket and has become very popular in recent years. This research focuses on bringing these concepts together by proposing a binary integer program to determine a team selection strategy for fantasy league cricket. This is done in a Twenty20 setting. The approach used in this study focuses on evaluating the effectiveness of previously developed performance measures in a fantasy league setting. Adjustments to these measures are made and new measures are proposed. These measures are then used to select a fantasy league team using a prospective approach. This is done to provide fantasy league participants with a mathematical procedure for fantasy league team selection.
- Full Text:
- Date Issued: 2010
An exploration of myth in the adaptation processes of Zimbabwean migrants residing in Port Elizabeth
- Authors: Kritzinger, Barbara
- Date: 2010
- Subjects: Migrant labor -- Zimbabwe , Migrant labor -- South Africa -- Port Elizabeth , Xenophobia -- South Africa -- Port Elizabeth , Immigrants -- Violence against -- South Africa , Migration, Internal -- Economic aspects -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:16136 , http://hdl.handle.net/10948/1430 , Migrant labor -- Zimbabwe , Migrant labor -- South Africa -- Port Elizabeth , Xenophobia -- South Africa -- Port Elizabeth , Immigrants -- Violence against -- South Africa , Migration, Internal -- Economic aspects -- Zimbabwe
- Description: Migration is recognised as an escalating phenomenon of human behaviour worldwide. In the Southern African region African migrations and migrants have remained a focal point of discussion amongst politicians, citizens and migrants themselves in recent years. In South Africa, a major destination of migrants from various African Diasporas, this renewed interest in the topic has occurred in the context of xenophobic related violence aimed at foreigners within the broader economic, political and social arena. These factors extend to South Africa’s relationships with her near neighbours. Thus, Zimbabwe’s political, economic and social crisis has overflowed into South African borders, contributing large numbers of migrants to her population. Previous research has underrepresented the perspectives of migrants and Zimbabwean migrants in particular. Zimbabwean migrants seek economic opportunities to better themselves and maintain the survival of their families who remain in their country of origin. They are transnationals who engage in continuous movement between one place and the next, supporting various livelihoods. Little is understood about migrant adaptation to their complex contexts. In this research project, content analysis was conducted of data gathered during interviews and participant-observation of Zimbabwean migrant traders on the beachfront informal market in Port Elizabeth. The maintenance of the cultural values and identity of the myth of the hero as upholder of household honour was found to be significant in the adaptation of migrants to their multi-faceted lives. The findings indicate that migrant life is indeed uncertain and ever-changing. Their resilience in the face of continual change illustrated both conflict and compromise between “social cohesiveness (and) social flexibility” (Bauman, 1998: 15-16)
- Full Text:
- Date Issued: 2010
An exploration of myth in the adaptation processes of Zimbabwean migrants residing in Port Elizabeth
- Authors: Kritzinger, Barbara
- Date: 2010
- Subjects: Migrant labor -- Zimbabwe , Migrant labor -- South Africa -- Port Elizabeth , Xenophobia -- South Africa -- Port Elizabeth , Immigrants -- Violence against -- South Africa , Migration, Internal -- Economic aspects -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:16136 , http://hdl.handle.net/10948/1430 , Migrant labor -- Zimbabwe , Migrant labor -- South Africa -- Port Elizabeth , Xenophobia -- South Africa -- Port Elizabeth , Immigrants -- Violence against -- South Africa , Migration, Internal -- Economic aspects -- Zimbabwe
- Description: Migration is recognised as an escalating phenomenon of human behaviour worldwide. In the Southern African region African migrations and migrants have remained a focal point of discussion amongst politicians, citizens and migrants themselves in recent years. In South Africa, a major destination of migrants from various African Diasporas, this renewed interest in the topic has occurred in the context of xenophobic related violence aimed at foreigners within the broader economic, political and social arena. These factors extend to South Africa’s relationships with her near neighbours. Thus, Zimbabwe’s political, economic and social crisis has overflowed into South African borders, contributing large numbers of migrants to her population. Previous research has underrepresented the perspectives of migrants and Zimbabwean migrants in particular. Zimbabwean migrants seek economic opportunities to better themselves and maintain the survival of their families who remain in their country of origin. They are transnationals who engage in continuous movement between one place and the next, supporting various livelihoods. Little is understood about migrant adaptation to their complex contexts. In this research project, content analysis was conducted of data gathered during interviews and participant-observation of Zimbabwean migrant traders on the beachfront informal market in Port Elizabeth. The maintenance of the cultural values and identity of the myth of the hero as upholder of household honour was found to be significant in the adaptation of migrants to their multi-faceted lives. The findings indicate that migrant life is indeed uncertain and ever-changing. Their resilience in the face of continual change illustrated both conflict and compromise between “social cohesiveness (and) social flexibility” (Bauman, 1998: 15-16)
- Full Text:
- Date Issued: 2010
The impact of increasing electricity tariffs on the automative industry in South Africa
- Authors: Hoops, Eduard Christiaan
- Date: 2010
- Subjects: Electricity -- Costs , Electric utilities -- Rates
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8639 , http://hdl.handle.net/10948/1436 , Electricity -- Costs , Electric utilities -- Rates
- Description: South African electricity tariffs were relatively low compared to the rest of the world. The average South African business has for long taken this advantage for granted and is now surprised to realise that electricity is becoming an expensive and scarce commodity. The South African electricity supply industry is far more complex than the average person may think. The infrastructure supporting this industry is extremely costly; takes long to develop and build and requires careful planning and management. There are many sources of energy and many technologies for generating electricity. However, many of these do not appear quite ready to serve the needs of the industry. The manufacturing industry depends heavily on electricity. The recent power outages and tariff increases have served as a cruel reminder of this fact. The automotive sector has lost many days of production and the increasing electricity costs erode the profitability of the affected companies. The automotive suppliers and vehicle manufacturers have expressed their concerns. Indications are that some have reduced the number of employees and may even face bankruptcy. This research aims to gain the perspective of senior managers in the automotive industry regarding the impact of the increased electricity tariffs on their manufacturing costs. Naturally, all electricity consumers will be affected by this. However, this research aims to investigate the significance of the effect on the automotive industry as well as obtain some indication of which factors determine the level of dependency. Each company has to react strategically to the situation and apply those measures which are available to them. This research determines how strongly the industry feels about reacting and which strategic measures they will apply. The outcome is descriptive of the circumstances in the industry and indisputably serves as an indication of the financial impact of electricity tariff increases.
- Full Text:
- Date Issued: 2010
- Authors: Hoops, Eduard Christiaan
- Date: 2010
- Subjects: Electricity -- Costs , Electric utilities -- Rates
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8639 , http://hdl.handle.net/10948/1436 , Electricity -- Costs , Electric utilities -- Rates
- Description: South African electricity tariffs were relatively low compared to the rest of the world. The average South African business has for long taken this advantage for granted and is now surprised to realise that electricity is becoming an expensive and scarce commodity. The South African electricity supply industry is far more complex than the average person may think. The infrastructure supporting this industry is extremely costly; takes long to develop and build and requires careful planning and management. There are many sources of energy and many technologies for generating electricity. However, many of these do not appear quite ready to serve the needs of the industry. The manufacturing industry depends heavily on electricity. The recent power outages and tariff increases have served as a cruel reminder of this fact. The automotive sector has lost many days of production and the increasing electricity costs erode the profitability of the affected companies. The automotive suppliers and vehicle manufacturers have expressed their concerns. Indications are that some have reduced the number of employees and may even face bankruptcy. This research aims to gain the perspective of senior managers in the automotive industry regarding the impact of the increased electricity tariffs on their manufacturing costs. Naturally, all electricity consumers will be affected by this. However, this research aims to investigate the significance of the effect on the automotive industry as well as obtain some indication of which factors determine the level of dependency. Each company has to react strategically to the situation and apply those measures which are available to them. This research determines how strongly the industry feels about reacting and which strategic measures they will apply. The outcome is descriptive of the circumstances in the industry and indisputably serves as an indication of the financial impact of electricity tariff increases.
- Full Text:
- Date Issued: 2010
The invasive ‘mothcatcher’ (Araujia sericifera Brot.; Asclepiadoideae) co-opts native honeybees as its primary pollinator in South Africa
- Coombs, Gareth, Peter, Craig I
- Authors: Coombs, Gareth , Peter, Craig I
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6510 , http://hdl.handle.net/10962/d1005937
- Description: Background and aims: Successful invasive plants such as Araujia sericifera usually either are capable of automatic self-pollination or maintain pollinator services by having generalized pollination systems to make use of local pollinators in the invaded range. Alternatively, plants must co-opt new pollinators with similar morphology to native pollinators or reproduce asexually. We aimed to document the pollination biology of A. sericifera in South Africa. Given the success of this species as an invader, we predicted that sexual reproduction occurs either through self-pollination or because A. sericifera has successfully co-opted native insect pollinators. Methodology: We examined the pollination biology of the South American A. sericifera in South Africa. We documented the effective pollinators including a comparison of the efficacy of nocturnal versus diurnal pollinators as well as the breeding system and long-term natural levels of the pollination success of this species. Principal results: We found that native honeybees (Apis mellifera) were the main pollinators of A. sericifera in South Africa. Visiting moths are unimportant pollinators despite being attracted by the pale colour and nocturnal scent of the flowers. Plants from the Grahamstown population were incapable of autonomous self-pollination but pollinator-mediated self-pollination does occur. However, the highest fruit initiation resulted from out-crossed pollination treatments. The high pollen transfer efficiency of this species was comparable to other hymenopteranpollinated exotic and native milkweeds, suggesting that A. sericifera maintains pollinator services at levels experienced by indigenous asclepiad species. Conclusions: Araujia sericifera reproduces successfully in South Africa due to a combined ability of this species to attract and exploit native honeybees as its pollinators and of individual plants to set fruit from pollinator-mediated self-pollination.
- Full Text:
- Date Issued: 2010
- Authors: Coombs, Gareth , Peter, Craig I
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6510 , http://hdl.handle.net/10962/d1005937
- Description: Background and aims: Successful invasive plants such as Araujia sericifera usually either are capable of automatic self-pollination or maintain pollinator services by having generalized pollination systems to make use of local pollinators in the invaded range. Alternatively, plants must co-opt new pollinators with similar morphology to native pollinators or reproduce asexually. We aimed to document the pollination biology of A. sericifera in South Africa. Given the success of this species as an invader, we predicted that sexual reproduction occurs either through self-pollination or because A. sericifera has successfully co-opted native insect pollinators. Methodology: We examined the pollination biology of the South American A. sericifera in South Africa. We documented the effective pollinators including a comparison of the efficacy of nocturnal versus diurnal pollinators as well as the breeding system and long-term natural levels of the pollination success of this species. Principal results: We found that native honeybees (Apis mellifera) were the main pollinators of A. sericifera in South Africa. Visiting moths are unimportant pollinators despite being attracted by the pale colour and nocturnal scent of the flowers. Plants from the Grahamstown population were incapable of autonomous self-pollination but pollinator-mediated self-pollination does occur. However, the highest fruit initiation resulted from out-crossed pollination treatments. The high pollen transfer efficiency of this species was comparable to other hymenopteranpollinated exotic and native milkweeds, suggesting that A. sericifera maintains pollinator services at levels experienced by indigenous asclepiad species. Conclusions: Araujia sericifera reproduces successfully in South Africa due to a combined ability of this species to attract and exploit native honeybees as its pollinators and of individual plants to set fruit from pollinator-mediated self-pollination.
- Full Text:
- Date Issued: 2010