Bayesian logistic regression models for credit scoring
- Authors: Webster, Gregg
- Date: 2011
- Subjects: Bayesian statistical decision theory Credit scoring systems Regression analysis Logistic regression analysis Monte Carlo method Markov processes Financial institutions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:5574 , http://hdl.handle.net/10962/d1005538
- Description: The Bayesian approach to logistic regression modelling for credit scoring is useful when there are data quantity issues. Data quantity issues might occur when a bank is opening in a new location or there is change in the scoring procedure. Making use of prior information (available from the coefficients estimated on other data sets, or expert knowledge about the coefficients) a Bayesian approach is proposed to improve the credit scoring models. To achieve this, a data set is split into two sets, “old” data and “new” data. Priors are obtained from a model fitted on the “old” data. This model is assumed to be a scoring model used by a financial institution in the current location. The financial institution is then assumed to expand into a new economic location where there is limited data. The priors from the model on the “old” data are then combined in a Bayesian model with the “new” data to obtain a model which represents all the available information. The predictive performance of this Bayesian model is compared to a model which does not make use of any prior information. It is found that the use of relevant prior information improves the predictive performance when the size of the “new” data is small. As the size of the “new” data increases, the importance of including prior information decreases
- Full Text:
- Date Issued: 2011
- Authors: Webster, Gregg
- Date: 2011
- Subjects: Bayesian statistical decision theory Credit scoring systems Regression analysis Logistic regression analysis Monte Carlo method Markov processes Financial institutions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:5574 , http://hdl.handle.net/10962/d1005538
- Description: The Bayesian approach to logistic regression modelling for credit scoring is useful when there are data quantity issues. Data quantity issues might occur when a bank is opening in a new location or there is change in the scoring procedure. Making use of prior information (available from the coefficients estimated on other data sets, or expert knowledge about the coefficients) a Bayesian approach is proposed to improve the credit scoring models. To achieve this, a data set is split into two sets, “old” data and “new” data. Priors are obtained from a model fitted on the “old” data. This model is assumed to be a scoring model used by a financial institution in the current location. The financial institution is then assumed to expand into a new economic location where there is limited data. The priors from the model on the “old” data are then combined in a Bayesian model with the “new” data to obtain a model which represents all the available information. The predictive performance of this Bayesian model is compared to a model which does not make use of any prior information. It is found that the use of relevant prior information improves the predictive performance when the size of the “new” data is small. As the size of the “new” data increases, the importance of including prior information decreases
- Full Text:
- Date Issued: 2011
Being Indian, being MK: an exploration of the experiences and ethnic identities of Indian South African Umkhonto we Sizwe members
- Authors: Lalla, Varsha
- Date: 2011
- Subjects: Umkhonto we Sizwe (South Africa) -- Research Political activists -- Research -- South Africa East Indians -- Politics and government -- Research -- South Africa Ethnicity -- Political aspects -- South Africa -- Research
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2792 , http://hdl.handle.net/10962/d1003002
- Description: Umkhonto we Sizwe (MK) was a military organization dominated by black Africans. Although it is not generally associated with Indian South Africans, who form a minority in the country, there were Indian MK members. This thesis explores the way in which Indian MK members reconciled aspects of their ethnic identity with their membership of MK. It explores the experiences of two generations of members: those born between 1929 and 1944 and those born between 1960 and 1969. In particular it looks at whether they experienced tensions between their ethnic and political identities. It explores what set these Indian South Africans apart from the rest of the Indian South African community that did not join MK. It also looks at what significant differences there were between different generations of Indian MK members. The research results show that the first generation MK members believe that their MK activities were „the highest form of passive resistance‟. An explanation for this way of referring to their activities could be that this was a way of reconciling tensions between their ethnic and political identities. The first generation was also very critical of the Indian SA community. This could be because they still feel part of this community despite having a strong political consciousness that is different from most of the community. It was found that some of the features that set Indian MK members apart from other Indian South Africans were that they were not raised in very religious households and occupied a fairly low rather than „middle man‟ economic position. In addition, members of the first generation of MK members were raised in comparatively multi-racial areas. Both generations made the decision to join MK because of Indian role models. There were some marked differences between the two generations of MK veterans. Most notably, the younger did not see their activities as in line with passive resistance and they also displayed more ambivalence about their ethnic identities.
- Full Text:
- Date Issued: 2011
- Authors: Lalla, Varsha
- Date: 2011
- Subjects: Umkhonto we Sizwe (South Africa) -- Research Political activists -- Research -- South Africa East Indians -- Politics and government -- Research -- South Africa Ethnicity -- Political aspects -- South Africa -- Research
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2792 , http://hdl.handle.net/10962/d1003002
- Description: Umkhonto we Sizwe (MK) was a military organization dominated by black Africans. Although it is not generally associated with Indian South Africans, who form a minority in the country, there were Indian MK members. This thesis explores the way in which Indian MK members reconciled aspects of their ethnic identity with their membership of MK. It explores the experiences of two generations of members: those born between 1929 and 1944 and those born between 1960 and 1969. In particular it looks at whether they experienced tensions between their ethnic and political identities. It explores what set these Indian South Africans apart from the rest of the Indian South African community that did not join MK. It also looks at what significant differences there were between different generations of Indian MK members. The research results show that the first generation MK members believe that their MK activities were „the highest form of passive resistance‟. An explanation for this way of referring to their activities could be that this was a way of reconciling tensions between their ethnic and political identities. The first generation was also very critical of the Indian SA community. This could be because they still feel part of this community despite having a strong political consciousness that is different from most of the community. It was found that some of the features that set Indian MK members apart from other Indian South Africans were that they were not raised in very religious households and occupied a fairly low rather than „middle man‟ economic position. In addition, members of the first generation of MK members were raised in comparatively multi-racial areas. Both generations made the decision to join MK because of Indian role models. There were some marked differences between the two generations of MK veterans. Most notably, the younger did not see their activities as in line with passive resistance and they also displayed more ambivalence about their ethnic identities.
- Full Text:
- Date Issued: 2011
Benefication of glycerol from algae and vegetable oil
- Authors: Mafu, Lubabalo Rowan
- Date: 2011
- Subjects: Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10409 , http://hdl.handle.net/10948/d1011503 , Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Description: This research has been directed at furthering the utilization of crude glycerol oversupply formed as a by-product from the biodiesel manufacturing process. Phosphorylation of hydroxyl groups is a synthetic route that was investigated for the conversion of glycerol into a glycerol-phosphate (GPE) ester mixture. The process investigated for the synthesis of a GPE product was based on phosphorylation reaction procedures that were previously reported in the literature. The reaction to convert glycerol into a GPE mixture has been thoroughly investigated and the hydrogen chloride gas formed as a reaction by-product has been optimized. The chemical properties of GPE have been studied and discussed together with a mass balance of the overall glycerol phosphorylation process. The phosphate groups contained in polyhydric phosphate molecules have a potential chelating effect on cations. There are several cations that may be chelated by the phosphate ester group of polyhydric phosphate molecules. These cations include ammonium (NH4+), Potassium (K+), Calcium (Ca2+) etc, which are essential as nutrients in plant fertilizer formulations. This research has investigated the use of a GPE synthesized from glycerol in the laboratory and the use thereof as a phosphorus containing base in the formulation and evaluation of Nitrogen, Phosphorus and Potassium (NPK) containing fertilizer solution, Ammonium-Potassium-Glycerol-Phosphate (APGP) fertilizer solution. The APGP fertilizer solution has further been evaluated by growing two week old tomato seedlings under controlled conditions. The performance of the APGP fertiliser solution has been evaluated using design of experiments by comparison with traditionally used liquidAmmonium-Potassium-Phosphate inorganic fertilizer. This fertilizer solution has been prepared in similar manner as APGP formulation with the difference between them being the source of phosphorus. The results have been evaluated using statistic analysis where a significant difference between the evaluated fertilizer formulations was found. The comparative study of these formulations was monitored by the observed plant weights. A blank treatment was used as a control to determine if a significant difference among these formulations was observed. Anova single factor and t-Test methods (Two-Samples assumed of equal variances) are statistical models that were applied to interpret the observed experimental data with respect to wet and dry weighed masses of tomato seedlings. These methods indicated a confirmed conclusion that there was a significant difference between APPO4 solution and APGP solution. The observed data have shown that the APPO4 solution provided significantly better fertigation performance than APGP solution. Consequently, further investigation has been conducted to determine the cause of the poorer performance of the APGP solution. The further study of the APGP fertilizer solution included nutrient stability testing, biological analysis and other observed physical changes of the APGP solution over time. Biological results have revealed the presence of a Fusarium fungus species that has grown and is suspended in APGP fertilizer solution. This microbe species has been observed to play a vital role in consuming fertilizer nutrients. In addition, the observed abnormal plant growth and nutrient decomposition of the APGP formulation has been proposed to be mostly a result of the pathogenicity of the fusarium fungi species that was suspended in the APGP solution. Further work has been proposed in which the effect of such biological contamination is eliminated through adequate sterilization procedures and the APGP formulation re-evaluated.
- Full Text:
- Date Issued: 2011
- Authors: Mafu, Lubabalo Rowan
- Date: 2011
- Subjects: Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10409 , http://hdl.handle.net/10948/d1011503 , Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Description: This research has been directed at furthering the utilization of crude glycerol oversupply formed as a by-product from the biodiesel manufacturing process. Phosphorylation of hydroxyl groups is a synthetic route that was investigated for the conversion of glycerol into a glycerol-phosphate (GPE) ester mixture. The process investigated for the synthesis of a GPE product was based on phosphorylation reaction procedures that were previously reported in the literature. The reaction to convert glycerol into a GPE mixture has been thoroughly investigated and the hydrogen chloride gas formed as a reaction by-product has been optimized. The chemical properties of GPE have been studied and discussed together with a mass balance of the overall glycerol phosphorylation process. The phosphate groups contained in polyhydric phosphate molecules have a potential chelating effect on cations. There are several cations that may be chelated by the phosphate ester group of polyhydric phosphate molecules. These cations include ammonium (NH4+), Potassium (K+), Calcium (Ca2+) etc, which are essential as nutrients in plant fertilizer formulations. This research has investigated the use of a GPE synthesized from glycerol in the laboratory and the use thereof as a phosphorus containing base in the formulation and evaluation of Nitrogen, Phosphorus and Potassium (NPK) containing fertilizer solution, Ammonium-Potassium-Glycerol-Phosphate (APGP) fertilizer solution. The APGP fertilizer solution has further been evaluated by growing two week old tomato seedlings under controlled conditions. The performance of the APGP fertiliser solution has been evaluated using design of experiments by comparison with traditionally used liquidAmmonium-Potassium-Phosphate inorganic fertilizer. This fertilizer solution has been prepared in similar manner as APGP formulation with the difference between them being the source of phosphorus. The results have been evaluated using statistic analysis where a significant difference between the evaluated fertilizer formulations was found. The comparative study of these formulations was monitored by the observed plant weights. A blank treatment was used as a control to determine if a significant difference among these formulations was observed. Anova single factor and t-Test methods (Two-Samples assumed of equal variances) are statistical models that were applied to interpret the observed experimental data with respect to wet and dry weighed masses of tomato seedlings. These methods indicated a confirmed conclusion that there was a significant difference between APPO4 solution and APGP solution. The observed data have shown that the APPO4 solution provided significantly better fertigation performance than APGP solution. Consequently, further investigation has been conducted to determine the cause of the poorer performance of the APGP solution. The further study of the APGP fertilizer solution included nutrient stability testing, biological analysis and other observed physical changes of the APGP solution over time. Biological results have revealed the presence of a Fusarium fungus species that has grown and is suspended in APGP fertilizer solution. This microbe species has been observed to play a vital role in consuming fertilizer nutrients. In addition, the observed abnormal plant growth and nutrient decomposition of the APGP formulation has been proposed to be mostly a result of the pathogenicity of the fusarium fungi species that was suspended in the APGP solution. Further work has been proposed in which the effect of such biological contamination is eliminated through adequate sterilization procedures and the APGP formulation re-evaluated.
- Full Text:
- Date Issued: 2011
Bioactivity and phytochemical analysis of Hydnora Africana on some selected bacterial pathogens
- Authors: Nethathe, Bono Bianca
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11247 , http://hdl.handle.net/10353/d1001063 , Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Description: Abstract Medicinal plants have been for long remedies for human diseases because they contain components of therapeutic value. The growing problem of antibiotic resistance by organisms demands the search for novel compounds from plant based sources. The present study was aimed at evaluating the bioactivity and phytochemical analysis of Hydnora africana on clinical and standard strains of Helicobacter pylori (PE 252C and ATCC 43526), Aeromonas hydrophila ATCC 35654, and Staphylococcus aureus NCT 6571 in an effort to identify potential sources of cheap starting materials for the synthesis of new drugs against these strains. Ethyl acetate, acetone, ethanol, methanol, and water crude extracts of H. africana were screened for activity against the test organisms using the agar well diffusion assay. The Minimum Inhibitory Concentration (MIC50) and Minimum Bactericidal Concentration (MBC) of the most potent extracts were determined by the microdilution method, followed by qualitative phytochemical analysis. Results were analyzed statistically by ANOVA one - way test. Different concentrations (200,100, 50mg/mL) of the methanol, acetone, ethanol and ethyl acetate extracts showed activity against S. aureus and A. hydrophila while for H. pylori, only methanol and ethyl acetate extracts were active; water showed no activity for all studied bacterial pathogens. Mean zone diameter of inhibition which ranged from 0-22mm were observed for all test bacterial pathogens and 14-17mm for ciprofloxacin. The activity of methanol and ethyl acetate extracts were statistically significant (P< 0.05) compared to all the other extracts. MIC50 and MBC ranged from 0.078 – 2.5mg/mL, 0.78-25mg/mL respectively for all tested bacterial pathogens. For ciprofloxacin, the MIC50 and MBC ranged from 0.00976 – 0.078mg/mL and 0.098– 0.78mg/mL respectively. There was no statistically significant difference between extracts (methanol, acetone, ethanol, ethyl acetate) and the control antibiotic (ciprofloxacin) (P> 0.05). Qualitative phytochemical analysis confirmed the presence of alkaloids, saponins, steroids, tannins and flavonoids in the methanol, acetone,ethanol and ethyl acetate extracts. The results demonstrate that H. africana may contain compounds with therapeutic potentials which can be lead molecules for semi-synthesis of new drugs.
- Full Text:
- Date Issued: 2011
- Authors: Nethathe, Bono Bianca
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11247 , http://hdl.handle.net/10353/d1001063 , Helicobacter pylori , Medicinal plants -- South Africa -- Eastern Cape , Microbial sensitivity tests , Herbs -- Therapeutic use -- South Africa -- Eastern Cape , Plants -- Analysis , Staphylococcus aureus , Aeromonas hydrophila , Drug resistance in microorganisms , Plant-pathogen relationships
- Description: Abstract Medicinal plants have been for long remedies for human diseases because they contain components of therapeutic value. The growing problem of antibiotic resistance by organisms demands the search for novel compounds from plant based sources. The present study was aimed at evaluating the bioactivity and phytochemical analysis of Hydnora africana on clinical and standard strains of Helicobacter pylori (PE 252C and ATCC 43526), Aeromonas hydrophila ATCC 35654, and Staphylococcus aureus NCT 6571 in an effort to identify potential sources of cheap starting materials for the synthesis of new drugs against these strains. Ethyl acetate, acetone, ethanol, methanol, and water crude extracts of H. africana were screened for activity against the test organisms using the agar well diffusion assay. The Minimum Inhibitory Concentration (MIC50) and Minimum Bactericidal Concentration (MBC) of the most potent extracts were determined by the microdilution method, followed by qualitative phytochemical analysis. Results were analyzed statistically by ANOVA one - way test. Different concentrations (200,100, 50mg/mL) of the methanol, acetone, ethanol and ethyl acetate extracts showed activity against S. aureus and A. hydrophila while for H. pylori, only methanol and ethyl acetate extracts were active; water showed no activity for all studied bacterial pathogens. Mean zone diameter of inhibition which ranged from 0-22mm were observed for all test bacterial pathogens and 14-17mm for ciprofloxacin. The activity of methanol and ethyl acetate extracts were statistically significant (P< 0.05) compared to all the other extracts. MIC50 and MBC ranged from 0.078 – 2.5mg/mL, 0.78-25mg/mL respectively for all tested bacterial pathogens. For ciprofloxacin, the MIC50 and MBC ranged from 0.00976 – 0.078mg/mL and 0.098– 0.78mg/mL respectively. There was no statistically significant difference between extracts (methanol, acetone, ethanol, ethyl acetate) and the control antibiotic (ciprofloxacin) (P> 0.05). Qualitative phytochemical analysis confirmed the presence of alkaloids, saponins, steroids, tannins and flavonoids in the methanol, acetone,ethanol and ethyl acetate extracts. The results demonstrate that H. africana may contain compounds with therapeutic potentials which can be lead molecules for semi-synthesis of new drugs.
- Full Text:
- Date Issued: 2011
Biological control of Pereskia aculeata Miller (Cactaceae)
- Authors: Paterson, Iain Douglas
- Date: 2011
- Subjects: Pereskia -- Biological control -- South Africa Cactus -- Biological control -- South Africa Invasive plants -- Biological control -- South Africa Curculionidae -- South Africa Pyralidae -- South Africa Insects as biological pest control agents -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5825 , http://hdl.handle.net/10962/d1007653
- Description: Pereskia aculeata Miller (Cactaceae) is an environmental weed that is damaging to natural ecosystems in South Africa. The plant is native to Central and South America and was first recorded in South Africa in a botanical garden in 1858. In this thesis, research into the biological control of P. aculeata was conducted with the intention of improving the control of the weed. A pre-release study of the relationship between P. aculeata density and native plant biodiversity indicated that P. aculeata has a negative impact on native biodiversity. The native plant biodiversity associated with different P. aculeata densities was used to determine threshold values and goals for the control of the weed. A threshold value of 50% P. aculeata density was calculated, indicating that P. aculeata density must be maintained below 50% in order to conserve native plant biodiversity. The ultimate goal of the control programme should be to maintain P. aculeata densities below 30%. At these densities there was no significant difference in native plant biodiversity from if the weed were absent from the ecosystem. The biological control agent, Phenrica guérini Bechyne (Chrysomelidae), has been released in South Africa but the potential of the agent to impact P. aculeata is not known and no post release evaluation has been conducted. Impact assessment studies indicate that P. guérini does not impact P. aculeata, even at high densities, but the results of greenhouse experiments should be interpreted with caution because of problems with extrapolation into the field. Although observations in the field suggest that P. guérini has reduced P. aculeata densities at one site, it is clear that new biological control agents are needed to reduce the weed to acceptable levels. Identifying the origin of the South African P. aculeata population was believed to be important to the biological control programme due to the disjunct native distribution and intraspecific variation of the species. Natural enemies associated with plant genotypes in different parts of the native distribution may have developed specialised relationships with certain intraspecific variants of the plant, resulting in differences in agent efficacy on certain host plant genotypes. A molecular study indicated that the closest relatives to the South African weed population found in the native distribution were in Rio de Janeiro Province, Brazil. A bioassay experiment in which fitness related traits of the biological control agent, P. guérini, were measured on various P. aculeata genotypes was conducted to determine the importance of host plant intraspecific variation. There was little variation in fitness traits between genotypes and no evidence of intraspecific host plant specialization. Although intraspecific variation had no effect on agent efficacy in the case of P. guérini, it is possible that other natural enemies may be more specialized. Genotype matching is expected to be more important when natural enemies likely to be specialised to individual genotypes are considered for biological control. Potential biological control agents were prioritized from data collected on surveys in the native distribution. The most promising of these, based on the presence of feeding, incidence, predicted host range, climatic matching, genotype matching and mode of damage, are two species of Curculionidae, the current biological control agent P. guérini and the stem boring moth, Maracayia chiorisalis Walker (Crambidae). The two curculionid species and M. chlorisalis should be considered priorities for host specificity studies. Releases of P. guérini and any new biological control agents should be made at sites where the pre-release study was conducted so that post-release evaluation data can be compared with the pre-release data and the impact of biological control can be evaluated. Retrospective analyses of biological control programmes provide important ways of improving aspects of biological control programmes, such as methods of agent selection. The evaluation of success in biological control programmes is essential for retrospective analyses because factors that have lead to successes or failures can be analysed. Retrospective analyses of biological control programmes, such as this thesis, may improve weed management, thereby contributing to the conservation of natural resources.
- Full Text:
- Date Issued: 2011
- Authors: Paterson, Iain Douglas
- Date: 2011
- Subjects: Pereskia -- Biological control -- South Africa Cactus -- Biological control -- South Africa Invasive plants -- Biological control -- South Africa Curculionidae -- South Africa Pyralidae -- South Africa Insects as biological pest control agents -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5825 , http://hdl.handle.net/10962/d1007653
- Description: Pereskia aculeata Miller (Cactaceae) is an environmental weed that is damaging to natural ecosystems in South Africa. The plant is native to Central and South America and was first recorded in South Africa in a botanical garden in 1858. In this thesis, research into the biological control of P. aculeata was conducted with the intention of improving the control of the weed. A pre-release study of the relationship between P. aculeata density and native plant biodiversity indicated that P. aculeata has a negative impact on native biodiversity. The native plant biodiversity associated with different P. aculeata densities was used to determine threshold values and goals for the control of the weed. A threshold value of 50% P. aculeata density was calculated, indicating that P. aculeata density must be maintained below 50% in order to conserve native plant biodiversity. The ultimate goal of the control programme should be to maintain P. aculeata densities below 30%. At these densities there was no significant difference in native plant biodiversity from if the weed were absent from the ecosystem. The biological control agent, Phenrica guérini Bechyne (Chrysomelidae), has been released in South Africa but the potential of the agent to impact P. aculeata is not known and no post release evaluation has been conducted. Impact assessment studies indicate that P. guérini does not impact P. aculeata, even at high densities, but the results of greenhouse experiments should be interpreted with caution because of problems with extrapolation into the field. Although observations in the field suggest that P. guérini has reduced P. aculeata densities at one site, it is clear that new biological control agents are needed to reduce the weed to acceptable levels. Identifying the origin of the South African P. aculeata population was believed to be important to the biological control programme due to the disjunct native distribution and intraspecific variation of the species. Natural enemies associated with plant genotypes in different parts of the native distribution may have developed specialised relationships with certain intraspecific variants of the plant, resulting in differences in agent efficacy on certain host plant genotypes. A molecular study indicated that the closest relatives to the South African weed population found in the native distribution were in Rio de Janeiro Province, Brazil. A bioassay experiment in which fitness related traits of the biological control agent, P. guérini, were measured on various P. aculeata genotypes was conducted to determine the importance of host plant intraspecific variation. There was little variation in fitness traits between genotypes and no evidence of intraspecific host plant specialization. Although intraspecific variation had no effect on agent efficacy in the case of P. guérini, it is possible that other natural enemies may be more specialized. Genotype matching is expected to be more important when natural enemies likely to be specialised to individual genotypes are considered for biological control. Potential biological control agents were prioritized from data collected on surveys in the native distribution. The most promising of these, based on the presence of feeding, incidence, predicted host range, climatic matching, genotype matching and mode of damage, are two species of Curculionidae, the current biological control agent P. guérini and the stem boring moth, Maracayia chiorisalis Walker (Crambidae). The two curculionid species and M. chlorisalis should be considered priorities for host specificity studies. Releases of P. guérini and any new biological control agents should be made at sites where the pre-release study was conducted so that post-release evaluation data can be compared with the pre-release data and the impact of biological control can be evaluated. Retrospective analyses of biological control programmes provide important ways of improving aspects of biological control programmes, such as methods of agent selection. The evaluation of success in biological control programmes is essential for retrospective analyses because factors that have lead to successes or failures can be analysed. Retrospective analyses of biological control programmes, such as this thesis, may improve weed management, thereby contributing to the conservation of natural resources.
- Full Text:
- Date Issued: 2011
Biomechanical, physiological and perceptual responses of three different athlete groups to the cycle-run transition
- Authors: Cripwell, Devin Matthew
- Date: 2011
- Subjects: Biomechanics -- Research , Human mechanics -- Research , Cycling -- Physiological aspects -- Research , Running -- Physiological aspects -- Research , Exercise -- Physiological aspects -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5106 , http://hdl.handle.net/10962/d1005184 , Biomechanics -- Research , Human mechanics -- Research , Cycling -- Physiological aspects -- Research , Running -- Physiological aspects -- Research , Exercise -- Physiological aspects -- Research
- Description: The transition from cycling to running has been identified as one of the key determinants of success in triathlon, as it has been suggested that the cycle may affect subsequent running efficiency such that running performance is significantly altered or reduced. It is also suggested that athletes more adapted to the transition itself, rather than purely running or cycling, may be more efficient during the post-cycle running bout. The current study sought to investigate the effects of prior cycling on subsequent selected biomechanical, physiological and perceptual responses of three different athlete groups. Subjects were selected on the basis of their sporting background, and were divided into three groups – triathletes, cyclists and runners. Experimentation required subjects to perform a seven minute treadmill running protocol at 15km.h⁻¹, during which biomechanical (EMG, Stride rate, Stride length, Vertical acceleration), physiological (HR, VO₂, EE) and perceptual (RPE) responses were recorded. After resting, subjects were required to perform a twenty minute stationary cycle at 70% of maximal aerobic power (previously determined), immediately followed by a second seven minute treadmill running protocol during which the same data were collected and compared to those collected during the first run. Biomechanical responses indicate that the cycle protocol had no effect on the muscle activity or vertical acceleration responses of any of the three subject groups, while the triathlete group significantly altered their gait responses in order to preserve running economy. The triathlete group was the least affected when considering the physiological responses, as running economy was preserved for this group. The runner and cyclist groups were significantly affected by the transition, as running economy decreased significantly for these groups. Perceptual responses indicate that athletes more experienced with the transition may find the transition from cycling to running to be easier than those inexperienced in this transition. It is apparent that a high intensity cycle protocol has limited statistical impact on selected biomechanical responses, while physiological and perceptual responses were altered, during a subsequent run, regardless of athlete type. That said, the ability of transition-trained athletes to transition comfortably between disciplines was highlighted, which may have important performance implications.
- Full Text:
- Date Issued: 2011
- Authors: Cripwell, Devin Matthew
- Date: 2011
- Subjects: Biomechanics -- Research , Human mechanics -- Research , Cycling -- Physiological aspects -- Research , Running -- Physiological aspects -- Research , Exercise -- Physiological aspects -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5106 , http://hdl.handle.net/10962/d1005184 , Biomechanics -- Research , Human mechanics -- Research , Cycling -- Physiological aspects -- Research , Running -- Physiological aspects -- Research , Exercise -- Physiological aspects -- Research
- Description: The transition from cycling to running has been identified as one of the key determinants of success in triathlon, as it has been suggested that the cycle may affect subsequent running efficiency such that running performance is significantly altered or reduced. It is also suggested that athletes more adapted to the transition itself, rather than purely running or cycling, may be more efficient during the post-cycle running bout. The current study sought to investigate the effects of prior cycling on subsequent selected biomechanical, physiological and perceptual responses of three different athlete groups. Subjects were selected on the basis of their sporting background, and were divided into three groups – triathletes, cyclists and runners. Experimentation required subjects to perform a seven minute treadmill running protocol at 15km.h⁻¹, during which biomechanical (EMG, Stride rate, Stride length, Vertical acceleration), physiological (HR, VO₂, EE) and perceptual (RPE) responses were recorded. After resting, subjects were required to perform a twenty minute stationary cycle at 70% of maximal aerobic power (previously determined), immediately followed by a second seven minute treadmill running protocol during which the same data were collected and compared to those collected during the first run. Biomechanical responses indicate that the cycle protocol had no effect on the muscle activity or vertical acceleration responses of any of the three subject groups, while the triathlete group significantly altered their gait responses in order to preserve running economy. The triathlete group was the least affected when considering the physiological responses, as running economy was preserved for this group. The runner and cyclist groups were significantly affected by the transition, as running economy decreased significantly for these groups. Perceptual responses indicate that athletes more experienced with the transition may find the transition from cycling to running to be easier than those inexperienced in this transition. It is apparent that a high intensity cycle protocol has limited statistical impact on selected biomechanical responses, while physiological and perceptual responses were altered, during a subsequent run, regardless of athlete type. That said, the ability of transition-trained athletes to transition comfortably between disciplines was highlighted, which may have important performance implications.
- Full Text:
- Date Issued: 2011
Bluetooth audio and video streaming on the J2ME platform
- Authors: Sahd, Curtis Lee
- Date: 2011 , 2010-09-09
- Subjects: Bluetooth technology , Mobile communication systems , Communication -- Technological innovations , Communication -- Network analysis , Wireless communication systems , L2TP (Computer network protocol) , Computer network protocols , Streaming audio , Streaming video
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4633 , http://hdl.handle.net/10962/d1006521 , Bluetooth technology , Mobile communication systems , Communication -- Technological innovations , Communication -- Network analysis , Wireless communication systems , L2TP (Computer network protocol) , Computer network protocols , Streaming audio , Streaming video
- Description: With the increase in bandwidth, more widespread distribution of media, and increased capability of mobile devices, multimedia streaming has not only become feasible, but more economical in terms of space occupied by the media file and the costs involved in attaining it. Although much attention has been paid to peer to peer media streaming over the Internet using HTTP and RTSP, little research has focussed on the use of the Bluetooth protocol for streaming audio and video between mobile devices. This project investigates the feasibility of Bluetooth as a protocol for audio and video streaming between mobile phones using the J2ME platform, through the analysis of Bluetooth protocols, media formats, optimum packet sizes, and the effects of distance on transfer speed. A comparison was made between RFCOMM and L2CAP to determine which protocol could support the fastest transfer speed between two mobile devices. The L2CAP protocol proved to be the most suitable, providing average transfer rates of 136.17 KBps. Using this protocol a second experiment was undertaken to determine the most suitable media format for streaming in terms of: file size, bandwidth usage, quality, and ease of implementation. Out of the eight media formats investigated, the MP3 format provided the smallest file size, smallest bandwidth usage, best quality and highest ease of implementation. Another experiment was conducted to determine the optimum packet size for transfer between devices. A tradeoff was found between packet size and the quality of the sound file, with highest transfer rates being recorded with the MTU size of 668 bytes (136.58 KBps). The class of Bluetooth transmitter typically used in mobile devices (class 2) is considered a weak signal and is adversely affected by distance. As such, the final investigation that was undertaken was aimed at determining the effects of distance on audio streaming and playback. As can be expected, when devices were situated close to each other, the transfer speeds obtained were higher than when devices were far apart. Readings were taken at varying distances (1-15 metres), with erratic transfer speeds observed from 7 metres onwards. This research showed that audio streaming on the J2ME platform is feasible, however using the currently available class of Bluetooth transmitter, video streaming is not feasible. Video files were only playable once the entire media file had been transferred.
- Full Text:
- Date Issued: 2011
- Authors: Sahd, Curtis Lee
- Date: 2011 , 2010-09-09
- Subjects: Bluetooth technology , Mobile communication systems , Communication -- Technological innovations , Communication -- Network analysis , Wireless communication systems , L2TP (Computer network protocol) , Computer network protocols , Streaming audio , Streaming video
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4633 , http://hdl.handle.net/10962/d1006521 , Bluetooth technology , Mobile communication systems , Communication -- Technological innovations , Communication -- Network analysis , Wireless communication systems , L2TP (Computer network protocol) , Computer network protocols , Streaming audio , Streaming video
- Description: With the increase in bandwidth, more widespread distribution of media, and increased capability of mobile devices, multimedia streaming has not only become feasible, but more economical in terms of space occupied by the media file and the costs involved in attaining it. Although much attention has been paid to peer to peer media streaming over the Internet using HTTP and RTSP, little research has focussed on the use of the Bluetooth protocol for streaming audio and video between mobile devices. This project investigates the feasibility of Bluetooth as a protocol for audio and video streaming between mobile phones using the J2ME platform, through the analysis of Bluetooth protocols, media formats, optimum packet sizes, and the effects of distance on transfer speed. A comparison was made between RFCOMM and L2CAP to determine which protocol could support the fastest transfer speed between two mobile devices. The L2CAP protocol proved to be the most suitable, providing average transfer rates of 136.17 KBps. Using this protocol a second experiment was undertaken to determine the most suitable media format for streaming in terms of: file size, bandwidth usage, quality, and ease of implementation. Out of the eight media formats investigated, the MP3 format provided the smallest file size, smallest bandwidth usage, best quality and highest ease of implementation. Another experiment was conducted to determine the optimum packet size for transfer between devices. A tradeoff was found between packet size and the quality of the sound file, with highest transfer rates being recorded with the MTU size of 668 bytes (136.58 KBps). The class of Bluetooth transmitter typically used in mobile devices (class 2) is considered a weak signal and is adversely affected by distance. As such, the final investigation that was undertaken was aimed at determining the effects of distance on audio streaming and playback. As can be expected, when devices were situated close to each other, the transfer speeds obtained were higher than when devices were far apart. Readings were taken at varying distances (1-15 metres), with erratic transfer speeds observed from 7 metres onwards. This research showed that audio streaming on the J2ME platform is feasible, however using the currently available class of Bluetooth transmitter, video streaming is not feasible. Video files were only playable once the entire media file had been transferred.
- Full Text:
- Date Issued: 2011
Brand loyalty in the South African tyre industry
- Authors: Stewart, Russel
- Date: 2011
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8796 , http://hdl.handle.net/10948/d1015983
- Description: The tyre industry plays an important role in the concept of mobility. Mobility defines the human need for transportation, which has been growing at an accelerated pace since the dawn of the nineteenth century. More importantly, modern mobility cannot be achieved without the use of a pneumatic tyre, a commodity that has become increasingly complex and competitive with countless brands and products available on a global scale. In order to stand out in this competitive market landscape, big brands attempt to build an amount of brand awareness within the market place, while maintaining a balance in creating a demand for their product in pull marketing strategies. While the market place becomes increasingly competitive on a both a global and local level, tyre brands are all trying various tactics in an effort to secure wheel positions on consumer’s vehicles. Within the marketing mix there are various strategies and tactics that can be adopted by tyre brands to secure a share of voice within the mind of the consumer when the need arises for new tyres, however in South Africa, only the established brands have the spending power to employ traditional media space in an effort to communicate with the consumer. It has also become increasingly difficult for established brands to remain dominant within the decision journey of consumers, especially when the retailer has the final contact with the consumer and may be promoting the purchase of a tyre brands that results in higher margins that the brand originally requested by the consumer. The tyre industry plays an important role in the concept of mobility. Mobility defines the human need for transportation, which has been growing at an accelerated pace since the dawn of the nineteenth century. More importantly, modern mobility cannot be achieved without the use of a pneumatic tyre, a commodity that has become increasingly complex and competitive with countless brands and products available on a global scale. In order to stand out in this competitive market landscape, big brands attempt to build an amount of brand awareness within the market place, while maintaining a balance in creating a demand for their product in pull marketing strategies. While the market place becomes increasingly competitive on a both a global and local level, tyre brands are all trying various tactics in an effort to secure wheel positions on consumer’s vehicles. Within the marketing mix there are various strategies and tactics that can be adopted by tyre brands to secure a share of voice within the mind of the consumer when the need arises for new tyres, however in South Africa, only the established brands have the spending power to employ traditional media space in an effort to communicate with the consumer. It has also become increasingly difficult for established brands to remain dominant within the decision journey of consumers, especially when the retailer has the final contact with the consumer and may be promoting the purchase of a tyre brands that results in higher margins that the brand originally requested by the consumer. The questions that remain are; do retailers have a high degree of influence on consumer behaviour or are high levels of brand awareness enough for a brand owner to be assured of a consistent demand on their product? This research aims to validate the interdependence of brand awareness and retailer influence on the consumer decision journey within the South African tyre industry. The research starts by setting the scene within the global and local tyre industry through the use of the Continental Corporation for illustration purposes. Once the scene is set in terms of the industry in which the research is taking place, brand theory is exhaustively discussed providing relevance and context within the tyre industry. Within the discussion of brand equity, the consumer decision journey and touch points are introduced as process and influence before the final purchase is made. With the theory of the tyre industry and branding covered, qualitative fieldwork was undertaken by two researchers at a tyre retail group in Tswane, South Africa. The fieldwork consisted of questionnaires that needed to be completed by consumers who had just concluded their purchase decision and were waiting in the retailer for the work to be concluded on their vehicle. The results of the fieldwork are extensively analysed and discussed upon which conclusions and recommendations for future research are drawn. The sample attained is sufficient for qualitative analysis; however the conclusions need to be read within the context of the sample size and geographical location in which the research was conducted. Further context was provided from the retail store owner who provided expert comment and insight based on experience within the industry and retail environment. The comment was utilised along with the theory to either validate or disprove findings, which formed the basis for recommendations for future research.
- Full Text:
- Date Issued: 2011
- Authors: Stewart, Russel
- Date: 2011
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8796 , http://hdl.handle.net/10948/d1015983
- Description: The tyre industry plays an important role in the concept of mobility. Mobility defines the human need for transportation, which has been growing at an accelerated pace since the dawn of the nineteenth century. More importantly, modern mobility cannot be achieved without the use of a pneumatic tyre, a commodity that has become increasingly complex and competitive with countless brands and products available on a global scale. In order to stand out in this competitive market landscape, big brands attempt to build an amount of brand awareness within the market place, while maintaining a balance in creating a demand for their product in pull marketing strategies. While the market place becomes increasingly competitive on a both a global and local level, tyre brands are all trying various tactics in an effort to secure wheel positions on consumer’s vehicles. Within the marketing mix there are various strategies and tactics that can be adopted by tyre brands to secure a share of voice within the mind of the consumer when the need arises for new tyres, however in South Africa, only the established brands have the spending power to employ traditional media space in an effort to communicate with the consumer. It has also become increasingly difficult for established brands to remain dominant within the decision journey of consumers, especially when the retailer has the final contact with the consumer and may be promoting the purchase of a tyre brands that results in higher margins that the brand originally requested by the consumer. The tyre industry plays an important role in the concept of mobility. Mobility defines the human need for transportation, which has been growing at an accelerated pace since the dawn of the nineteenth century. More importantly, modern mobility cannot be achieved without the use of a pneumatic tyre, a commodity that has become increasingly complex and competitive with countless brands and products available on a global scale. In order to stand out in this competitive market landscape, big brands attempt to build an amount of brand awareness within the market place, while maintaining a balance in creating a demand for their product in pull marketing strategies. While the market place becomes increasingly competitive on a both a global and local level, tyre brands are all trying various tactics in an effort to secure wheel positions on consumer’s vehicles. Within the marketing mix there are various strategies and tactics that can be adopted by tyre brands to secure a share of voice within the mind of the consumer when the need arises for new tyres, however in South Africa, only the established brands have the spending power to employ traditional media space in an effort to communicate with the consumer. It has also become increasingly difficult for established brands to remain dominant within the decision journey of consumers, especially when the retailer has the final contact with the consumer and may be promoting the purchase of a tyre brands that results in higher margins that the brand originally requested by the consumer. The questions that remain are; do retailers have a high degree of influence on consumer behaviour or are high levels of brand awareness enough for a brand owner to be assured of a consistent demand on their product? This research aims to validate the interdependence of brand awareness and retailer influence on the consumer decision journey within the South African tyre industry. The research starts by setting the scene within the global and local tyre industry through the use of the Continental Corporation for illustration purposes. Once the scene is set in terms of the industry in which the research is taking place, brand theory is exhaustively discussed providing relevance and context within the tyre industry. Within the discussion of brand equity, the consumer decision journey and touch points are introduced as process and influence before the final purchase is made. With the theory of the tyre industry and branding covered, qualitative fieldwork was undertaken by two researchers at a tyre retail group in Tswane, South Africa. The fieldwork consisted of questionnaires that needed to be completed by consumers who had just concluded their purchase decision and were waiting in the retailer for the work to be concluded on their vehicle. The results of the fieldwork are extensively analysed and discussed upon which conclusions and recommendations for future research are drawn. The sample attained is sufficient for qualitative analysis; however the conclusions need to be read within the context of the sample size and geographical location in which the research was conducted. Further context was provided from the retail store owner who provided expert comment and insight based on experience within the industry and retail environment. The comment was utilised along with the theory to either validate or disprove findings, which formed the basis for recommendations for future research.
- Full Text:
- Date Issued: 2011
Building employee value proposition for attracting and retaining talent in large organisations in South Africa
- Authors: Chen, Shih-hwa James
- Date: 2011
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9121 , http://hdl.handle.net/10948/d1016056
- Description: Globalisation of businesses and the advancement of information technology have changed the way employees think, live and behave. As a result, some of the traditional theories and models on talent management have been tested, and to some extent, challenged. Companies large and small must be creative, responsive and ready to let go outdated management practices when challenged by new paradigms to improve competitiveness and alignment to market needs. In the current climate of widespread skill shortages and declining workforce numbers, large organisations continue to wrestle with appropriate management practices that could truly protect their most valuable asset – its people. This research was aimed at providing an insight into what makes a good attraction and retention strategy for large organisations in South Africa. It further examined the principles which underpin an effective employee value proposition that would capture comprehensively the expectations, personal needs and career goals of the new generation employees especially in a developing economy. Quantitative data focusing on students‘ expectations on their future employer of choice was collected via a national survey distributed at 23 tertiary institutions in South Africa during career fairs. Qualitative data was collected through focus group discussions with a sample of SARS graduate employees. Triangulation of results was possible and the analysis of data provided scientific evidence for meaningful conclusions and recommendations. The findings of this research enabled the development of a structured argument in terms of what organisations need to start, stop and continue doing to improve the talent management practices for attracting, developing and retaining highly talented people. The research further enabled the identification of key components that are essential for building an attractive and practical EVP for large organizations that focus on enhancing the value of their talent in the 21st century.
- Full Text:
- Date Issued: 2011
- Authors: Chen, Shih-hwa James
- Date: 2011
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9121 , http://hdl.handle.net/10948/d1016056
- Description: Globalisation of businesses and the advancement of information technology have changed the way employees think, live and behave. As a result, some of the traditional theories and models on talent management have been tested, and to some extent, challenged. Companies large and small must be creative, responsive and ready to let go outdated management practices when challenged by new paradigms to improve competitiveness and alignment to market needs. In the current climate of widespread skill shortages and declining workforce numbers, large organisations continue to wrestle with appropriate management practices that could truly protect their most valuable asset – its people. This research was aimed at providing an insight into what makes a good attraction and retention strategy for large organisations in South Africa. It further examined the principles which underpin an effective employee value proposition that would capture comprehensively the expectations, personal needs and career goals of the new generation employees especially in a developing economy. Quantitative data focusing on students‘ expectations on their future employer of choice was collected via a national survey distributed at 23 tertiary institutions in South Africa during career fairs. Qualitative data was collected through focus group discussions with a sample of SARS graduate employees. Triangulation of results was possible and the analysis of data provided scientific evidence for meaningful conclusions and recommendations. The findings of this research enabled the development of a structured argument in terms of what organisations need to start, stop and continue doing to improve the talent management practices for attracting, developing and retaining highly talented people. The research further enabled the identification of key components that are essential for building an attractive and practical EVP for large organizations that focus on enhancing the value of their talent in the 21st century.
- Full Text:
- Date Issued: 2011
Business cycles and stock market performance in South Africa
- Authors: Muchaonyerwa, Forward
- Date: 2011
- Subjects: Stock exchanges -- South Africa , Economic indicators -- South Africa , Business cycles -- South Africa , Economic forecasting -- South Africa , Stocks -- South Africa
- Language: English
- Type: Thesis , Masters , M Com
- Identifier: vital:11460 , http://hdl.handle.net/10353/312 , Stock exchanges -- South Africa , Economic indicators -- South Africa , Business cycles -- South Africa , Economic forecasting -- South Africa , Stocks -- South Africa
- Description: The study investigates the relationship between stock market performance and business cycles in South Africa for the period 2002-2009 using monthly data. This is done by constructing a Vector Error Correction Model (VECM). The study specifies a business cycle model with the business cycle coincident indicator (BC) regressed against, the All Share Price Index (ALSI), Real Effective Exchange Rate (REER), Money Supply (M1), Inflation (CPIX) and the Prime Overdraft Rate (POR). The ALSI represents stock market performance whilst the rest of the variables are to enhance model specification. The study found a positive relationship between stock market performance and business cycles in South Africa. The results also indicated that business cycles are positively related to the lagged variable of the coincident indicator and money supply. In addition, the findings also reveal that BC is negatively related to interest rates and the real effective exchange rate.
- Full Text:
- Date Issued: 2011
- Authors: Muchaonyerwa, Forward
- Date: 2011
- Subjects: Stock exchanges -- South Africa , Economic indicators -- South Africa , Business cycles -- South Africa , Economic forecasting -- South Africa , Stocks -- South Africa
- Language: English
- Type: Thesis , Masters , M Com
- Identifier: vital:11460 , http://hdl.handle.net/10353/312 , Stock exchanges -- South Africa , Economic indicators -- South Africa , Business cycles -- South Africa , Economic forecasting -- South Africa , Stocks -- South Africa
- Description: The study investigates the relationship between stock market performance and business cycles in South Africa for the period 2002-2009 using monthly data. This is done by constructing a Vector Error Correction Model (VECM). The study specifies a business cycle model with the business cycle coincident indicator (BC) regressed against, the All Share Price Index (ALSI), Real Effective Exchange Rate (REER), Money Supply (M1), Inflation (CPIX) and the Prime Overdraft Rate (POR). The ALSI represents stock market performance whilst the rest of the variables are to enhance model specification. The study found a positive relationship between stock market performance and business cycles in South Africa. The results also indicated that business cycles are positively related to the lagged variable of the coincident indicator and money supply. In addition, the findings also reveal that BC is negatively related to interest rates and the real effective exchange rate.
- Full Text:
- Date Issued: 2011
Cattle manure, scalping and soil wetness effects on some physical properties of a hardsetting soil and associated early maize growth
- Authors: Nciizah, Adornis Dakarai
- Date: 2011
- Subjects: Soil formation , Crops and soils , Manures , Soil mechanics , Soil moisture , Soil stabilization , Soil penetration test
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11861 , http://hdl.handle.net/10353/349 , Soil formation , Crops and soils , Manures , Soil mechanics , Soil moisture , Soil stabilization , Soil penetration test
- Description: Most soils in the Eastern Cape Province, South Africa are shallow and are low in organic matter. Therefore these soils are structurally fragile and highly susceptible to inherent degradative processes like hardsetting. The objective of this study was to determine the effect of cattle manure, scalping and soil wetness on aggregate stability, penetration resistance and early maize growth in hardsetting soils. Glasshouse and field studies were conducted to determine the effect of cattle manure on aggregate stability and penetration resistance of freshly exposed topsoils by scalping at 0, 10 and 20 cm depths. In the glasshouse cattle manure was applied at 0 and 20 Mg/ha and matric suction was kept at ~ 30 and ~ 400 kPa; contrasting high and low soil wetness. Three soils were put in pots and arranged in a randomized complete block 3 2 2 factorial design. The field study was done at the University of Fort Hare research farm and the treatments were arranged in a split-plot complete randomized design with three replications. Scalping treatment was the main plot whilst the quantity of the cattle manure applied was the sub plot. Cattle manure increased mean weight diameter (MWD) by between 48% and 71% under glasshouse and between 18% and 33% under field conditions, depending on the soil wetting rate. Cattle manure reduced MWD when the soil under field condition was subjected to mechanical shaking. Soil penetration resistance decreased linearly, with increasing soil wetness but it rapidly increased with increase in matric suction up to ~200 kPa and thereafter the rate of increase reduced. In the glasshouse, all treatments had no significant effects on shoot dry weight but low matric suction increased root dry weight by 133%. Interaction of cattle manure and low matric suction reduced shoot length by 6%, shoot fresh weight by 25%, root surface area by 36%, root length by 5% and root fresh weight by 29% compared to the control. In contrast, application of cattle manure and high matric suction increased shoot length by 37%, shoot fresh weight by 136%, root surface area by 159%, root length by 94% and root fresh weight by 119%. In the field, cattle manure application increased root length density and shoot dry matter by 26% and 30% respectively. Cattle manure improved the stability of aggregates of the hardsetting soil under rapid or slow water intake conditions experienced during rainfall or irrigation. However, under field conditions cattle manure acted as a deflocculant and decreased the stability of aggregates when mechanical stress was applied. The effectiveness of cattle manure in improving maize growth in hardsetting soils was determined by matric suction.
- Full Text:
- Date Issued: 2011
- Authors: Nciizah, Adornis Dakarai
- Date: 2011
- Subjects: Soil formation , Crops and soils , Manures , Soil mechanics , Soil moisture , Soil stabilization , Soil penetration test
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11861 , http://hdl.handle.net/10353/349 , Soil formation , Crops and soils , Manures , Soil mechanics , Soil moisture , Soil stabilization , Soil penetration test
- Description: Most soils in the Eastern Cape Province, South Africa are shallow and are low in organic matter. Therefore these soils are structurally fragile and highly susceptible to inherent degradative processes like hardsetting. The objective of this study was to determine the effect of cattle manure, scalping and soil wetness on aggregate stability, penetration resistance and early maize growth in hardsetting soils. Glasshouse and field studies were conducted to determine the effect of cattle manure on aggregate stability and penetration resistance of freshly exposed topsoils by scalping at 0, 10 and 20 cm depths. In the glasshouse cattle manure was applied at 0 and 20 Mg/ha and matric suction was kept at ~ 30 and ~ 400 kPa; contrasting high and low soil wetness. Three soils were put in pots and arranged in a randomized complete block 3 2 2 factorial design. The field study was done at the University of Fort Hare research farm and the treatments were arranged in a split-plot complete randomized design with three replications. Scalping treatment was the main plot whilst the quantity of the cattle manure applied was the sub plot. Cattle manure increased mean weight diameter (MWD) by between 48% and 71% under glasshouse and between 18% and 33% under field conditions, depending on the soil wetting rate. Cattle manure reduced MWD when the soil under field condition was subjected to mechanical shaking. Soil penetration resistance decreased linearly, with increasing soil wetness but it rapidly increased with increase in matric suction up to ~200 kPa and thereafter the rate of increase reduced. In the glasshouse, all treatments had no significant effects on shoot dry weight but low matric suction increased root dry weight by 133%. Interaction of cattle manure and low matric suction reduced shoot length by 6%, shoot fresh weight by 25%, root surface area by 36%, root length by 5% and root fresh weight by 29% compared to the control. In contrast, application of cattle manure and high matric suction increased shoot length by 37%, shoot fresh weight by 136%, root surface area by 159%, root length by 94% and root fresh weight by 119%. In the field, cattle manure application increased root length density and shoot dry matter by 26% and 30% respectively. Cattle manure improved the stability of aggregates of the hardsetting soil under rapid or slow water intake conditions experienced during rainfall or irrigation. However, under field conditions cattle manure acted as a deflocculant and decreased the stability of aggregates when mechanical stress was applied. The effectiveness of cattle manure in improving maize growth in hardsetting soils was determined by matric suction.
- Full Text:
- Date Issued: 2011
Causes of high failure rate among matriculants in the Qumbu District, Eastern Cape, South Africa
- Ngewu, Caroline Pumza Bongeka
- Authors: Ngewu, Caroline Pumza Bongeka
- Date: 2011
- Subjects: Matric learners -- Failure rate -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18445 , http://hdl.handle.net/11260/d1007292
- Description: The study sought to establish the causes of high failure rate among matriculants in the Qumbu district in the Eastern Cape, South Africa. A qualitative research design was adopted. Interviews were used to collect data. The sample (N=21) was made up of 12 teachers, 3 learners from each of the selected 3 schools. Convenience sampling technique was used to select the participants. The data were thematically analyzed. The study concluded that parents were not involved in the teaching and learning of their children. There was a lack of learner-teacher support material and infrastructure in schools and this affected learner‟s performance. Disciplinary issues involving both teachers and learners negatively affected the performance of learners. The medium of instruction in schools also affected performance because in some schools learners were taught in Xhosa and that resulted in poor performance at school. The study recommended that parents need to be encouraged to be actively involved. Infrastructure needs to be improved in schools and more classrooms should be built. Learners need discipline and society at large should be involved in moulding learners and teachers‟ in this regard (Teachers should lead by example). In addition, teachers and learners need to be motivated to use English as a medium of instruction and teachers ought to use English when they communicate with learners.
- Full Text:
- Date Issued: 2011
- Authors: Ngewu, Caroline Pumza Bongeka
- Date: 2011
- Subjects: Matric learners -- Failure rate -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18445 , http://hdl.handle.net/11260/d1007292
- Description: The study sought to establish the causes of high failure rate among matriculants in the Qumbu district in the Eastern Cape, South Africa. A qualitative research design was adopted. Interviews were used to collect data. The sample (N=21) was made up of 12 teachers, 3 learners from each of the selected 3 schools. Convenience sampling technique was used to select the participants. The data were thematically analyzed. The study concluded that parents were not involved in the teaching and learning of their children. There was a lack of learner-teacher support material and infrastructure in schools and this affected learner‟s performance. Disciplinary issues involving both teachers and learners negatively affected the performance of learners. The medium of instruction in schools also affected performance because in some schools learners were taught in Xhosa and that resulted in poor performance at school. The study recommended that parents need to be encouraged to be actively involved. Infrastructure needs to be improved in schools and more classrooms should be built. Learners need discipline and society at large should be involved in moulding learners and teachers‟ in this regard (Teachers should lead by example). In addition, teachers and learners need to be motivated to use English as a medium of instruction and teachers ought to use English when they communicate with learners.
- Full Text:
- Date Issued: 2011
Challenges and prospects of quality primary education in Zimbabwe rural schools: a case study of Kadoma rural schools
- Authors: Mazise, Amos
- Date: 2011
- Subjects: Rural schools -- Zimbabwe Case studies , Education, Primary -- Zimbabwe Case studies , School management and organization -- Zimbabwe Case studies , Schools -- Zimbabwe -- Evaluation
- Language: English
- Type: Thesis , Masters , M Soc Sc (Dev)
- Identifier: vital:11428 , http://hdl.handle.net/10353/569 , Rural schools -- Zimbabwe Case studies , Education, Primary -- Zimbabwe Case studies , School management and organization -- Zimbabwe Case studies , Schools -- Zimbabwe -- Evaluation
- Description: The study focused on investigating challenges and prospects of quality education in rural primary schools in developing countries particularly in Zimbabwe. Reviewed literature indicated that two theories; education as human capital and education as human right advanced increased access to education. Decline of quality of education in the expansion programme portrayed by the decrease of pass rates to below 50 percent, pupils’ low literacy and numeracy prompted investigation. A case study of Ngezi rural primary schools was explored using a sample of 50 respondents selected through stratified random technique. Data were gathered by a combination of qualitative and quantitative methods defined as triangulation. Self- administered questionnaires for heads and teachers, interview guide for grade 7 pupils and SDC and observation guide were the instruments employed for data collection. Analysis of the data was done using descriptive statistics. Findings were that quality of universal education was affected by inadequate supporting inputs and facilities, inappropriate teaching methods and unmotivated teachers. However 80 percent of the schools were staffed with qualified teachers depicting government’s commitment to quality education. 40 % of the schools without qualified leadership were indicative of the effect of poor school conditions to staff turn up. In studies carried out in Kenya, Uganda, Tanzania and India quality also declined as access was increased due to similar causes. Recommendations were to create a strong collaboration among stakeholders through communication to ensure the four conditions for quality are met simultaneously as they are interdependent and reforming the curriculum to suit means and needs of the people.
- Full Text:
- Date Issued: 2011
- Authors: Mazise, Amos
- Date: 2011
- Subjects: Rural schools -- Zimbabwe Case studies , Education, Primary -- Zimbabwe Case studies , School management and organization -- Zimbabwe Case studies , Schools -- Zimbabwe -- Evaluation
- Language: English
- Type: Thesis , Masters , M Soc Sc (Dev)
- Identifier: vital:11428 , http://hdl.handle.net/10353/569 , Rural schools -- Zimbabwe Case studies , Education, Primary -- Zimbabwe Case studies , School management and organization -- Zimbabwe Case studies , Schools -- Zimbabwe -- Evaluation
- Description: The study focused on investigating challenges and prospects of quality education in rural primary schools in developing countries particularly in Zimbabwe. Reviewed literature indicated that two theories; education as human capital and education as human right advanced increased access to education. Decline of quality of education in the expansion programme portrayed by the decrease of pass rates to below 50 percent, pupils’ low literacy and numeracy prompted investigation. A case study of Ngezi rural primary schools was explored using a sample of 50 respondents selected through stratified random technique. Data were gathered by a combination of qualitative and quantitative methods defined as triangulation. Self- administered questionnaires for heads and teachers, interview guide for grade 7 pupils and SDC and observation guide were the instruments employed for data collection. Analysis of the data was done using descriptive statistics. Findings were that quality of universal education was affected by inadequate supporting inputs and facilities, inappropriate teaching methods and unmotivated teachers. However 80 percent of the schools were staffed with qualified teachers depicting government’s commitment to quality education. 40 % of the schools without qualified leadership were indicative of the effect of poor school conditions to staff turn up. In studies carried out in Kenya, Uganda, Tanzania and India quality also declined as access was increased due to similar causes. Recommendations were to create a strong collaboration among stakeholders through communication to ensure the four conditions for quality are met simultaneously as they are interdependent and reforming the curriculum to suit means and needs of the people.
- Full Text:
- Date Issued: 2011
Challenges facing school management teams in the general education and training band schools untitles
- Authors: Mapisa, Bafundi Zealous
- Date: 2011
- Subjects: School management -- Education and training
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18423 , http://hdl.handle.net/11260/d1006923
- Description: During the apartheid era, that is, before 1994, principals tended to regard schools as their properties. Principals were expected to manage schools on their own without consulting the rest of the staff. From 1994 with the advent of a new political era, South Africa ended up having one National Education System. That system came up with many changes. In the new education system, the management of the school was taken from being the principal‟s duty only, to the responsibility of a management team which is referred to as the school management team (SMT). Because of the democratic nature of the SMT, it is required that educators work co-operatively as a team. The researcher has observed that this has been a challenge in some schools where principals resisted change. On the other hand, principals of schools are facing challenges due to a lack of cooperation amongst their subordinates. The establishment of SMTs does not nullify the authority of the school principal but the challenge that lies therein is that each member of the SMT must play his or her role properly. The purpose of this study was to explore the challenges facing SMT members in the GET band schools of Circuit 2 in Centane. A qualitative investigation was undertaken with the purpose in mind to develop a better understanding of the challenges facing SMTs in Circuit 2. This study was undertaken among 5 schools in Circuit 2 in Centane which falls under Butterworth District. The researcher used convenience sampling in selecting the SMTs of schools that would participate in this research study. Due to the fact that the researcher is a principal in one of the schools in Circuit 2 he could obtain easy access to SMTs of other schools in the Circuit. The following stakeholders were identified and participated in the selected schools: principal, deputy principal and Head of Department. Qualitative data were collected through semi- structured interviews. The study was framed within the interpretive approach, and sought to unpack the perceptions of SMT members with regard to team-management . An interpretive paradigm made it possible for the researcher to gain an in-depth understanding of SMT members‟ perceptions of team-management within their contexts. The outcomes pointed to several challenges ranging from the SMT terms of reference, cooperation, sources of support and stress as a result of the work overload involved. Based on the findings, SMTs have brought the phenomenon of cooperation to the fore, and cooperation may be perceived to have many advantages. However, in order for the SMTs to play a meaningful role in curriculum management and governance issues, there is a need for them to be conversant with issues and kept abreast of developments in education as a system. It is therefore recommended that members of the SMT be exposed to continuing professional training and development in the aforementioned governance areas.
- Full Text:
- Date Issued: 2011
- Authors: Mapisa, Bafundi Zealous
- Date: 2011
- Subjects: School management -- Education and training
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18423 , http://hdl.handle.net/11260/d1006923
- Description: During the apartheid era, that is, before 1994, principals tended to regard schools as their properties. Principals were expected to manage schools on their own without consulting the rest of the staff. From 1994 with the advent of a new political era, South Africa ended up having one National Education System. That system came up with many changes. In the new education system, the management of the school was taken from being the principal‟s duty only, to the responsibility of a management team which is referred to as the school management team (SMT). Because of the democratic nature of the SMT, it is required that educators work co-operatively as a team. The researcher has observed that this has been a challenge in some schools where principals resisted change. On the other hand, principals of schools are facing challenges due to a lack of cooperation amongst their subordinates. The establishment of SMTs does not nullify the authority of the school principal but the challenge that lies therein is that each member of the SMT must play his or her role properly. The purpose of this study was to explore the challenges facing SMT members in the GET band schools of Circuit 2 in Centane. A qualitative investigation was undertaken with the purpose in mind to develop a better understanding of the challenges facing SMTs in Circuit 2. This study was undertaken among 5 schools in Circuit 2 in Centane which falls under Butterworth District. The researcher used convenience sampling in selecting the SMTs of schools that would participate in this research study. Due to the fact that the researcher is a principal in one of the schools in Circuit 2 he could obtain easy access to SMTs of other schools in the Circuit. The following stakeholders were identified and participated in the selected schools: principal, deputy principal and Head of Department. Qualitative data were collected through semi- structured interviews. The study was framed within the interpretive approach, and sought to unpack the perceptions of SMT members with regard to team-management . An interpretive paradigm made it possible for the researcher to gain an in-depth understanding of SMT members‟ perceptions of team-management within their contexts. The outcomes pointed to several challenges ranging from the SMT terms of reference, cooperation, sources of support and stress as a result of the work overload involved. Based on the findings, SMTs have brought the phenomenon of cooperation to the fore, and cooperation may be perceived to have many advantages. However, in order for the SMTs to play a meaningful role in curriculum management and governance issues, there is a need for them to be conversant with issues and kept abreast of developments in education as a system. It is therefore recommended that members of the SMT be exposed to continuing professional training and development in the aforementioned governance areas.
- Full Text:
- Date Issued: 2011
Characterization and electrocatalytic applications of metallophthalocyanine-single walled carbon nanotube conjugates
- Authors: Mugadza, Tawanda
- Date: 2011 , 2011-03-30
- Subjects: Phthalocyanines Pesticides Nanotubes Electrocatalysis Electrochemistry Transmission electron microscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4419 , http://hdl.handle.net/10962/d1006855
- Description: Metallophthalocyanine-single walled carbon nanotube conjugates were successfully synthesized and applied in the electrochemical characterizations of pesticides (amitrole and diuron) and 2-mercaptoethanol (2-ME). The formation of conjugates was confirmed through the use of the following analytical techniques: UV-vis, FTIR, Raman and XRD spectroscopies, atomic force and transmission electron microscopies and voltammetry. Chemically linking SWCNT to MPcs created platforms that offered efficient transfer of electrons and this was confirmed through electrochemical impedance studies (EIS) and voltammetry as shown by lower ΔEp values observed in conjugates. Carboxy carrying MPcs have very poor electron transfer kinetics (both tetrasubstituted and low symmetry), but the presence of SWCNTs activates their catalysis. All electrochemical studies were done at pH 4. Cyclic voltammetry, rotating disk linear sweep voltammetry, chronoamperometry and EIS were used in the electrochemical characterization of 2-ME and the pesticides on poly-Ni(OH)TAPc and MPc-SWCNT modified glassy carbon electrodes (GCEs). High Tafel slopes were observed for the pesticides relative to 2-ME, an indication of the passivating nature of their oxidation products. However, conjugates showed very high resistances to passivation and were easily regenerated by shaking in methanol. Improved catalysis of the conjugates is also indicated by the high catalytic rate constants for the analytes, observed on these electrodes. Conjugates of low symmetry MPcs with SWCNTs gave the highest catalytic rate constants, confirming better catalysis on these electrode surfaces. The nature of SWCNT functionalization also affected catalysis, with amine functionalized SWCNTs inducing better catalytic properties into the MPcs than carboxylic acid terminated CNTs. The presence of amine functionalized SWCNTs activates the catalysis of non-catalytic carboxy-carrying MPcs and this is more pronounced in conjugates of tetrasubstituted MPcs relative to those of low symmetry Pcs. Ethylene amine (EA) functionalized SWCNTs reduced redox overpotentials of the MPcs more than the phenyl-amine (PA) functionalized counterparts. Poly-NiTAPc was successfully converted to poly-Ni(OH)TAPc through cyclisation in pH 4 buffer and showed very good catalytic properties towards diuron, relative to the former.
- Full Text:
- Date Issued: 2011
- Authors: Mugadza, Tawanda
- Date: 2011 , 2011-03-30
- Subjects: Phthalocyanines Pesticides Nanotubes Electrocatalysis Electrochemistry Transmission electron microscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4419 , http://hdl.handle.net/10962/d1006855
- Description: Metallophthalocyanine-single walled carbon nanotube conjugates were successfully synthesized and applied in the electrochemical characterizations of pesticides (amitrole and diuron) and 2-mercaptoethanol (2-ME). The formation of conjugates was confirmed through the use of the following analytical techniques: UV-vis, FTIR, Raman and XRD spectroscopies, atomic force and transmission electron microscopies and voltammetry. Chemically linking SWCNT to MPcs created platforms that offered efficient transfer of electrons and this was confirmed through electrochemical impedance studies (EIS) and voltammetry as shown by lower ΔEp values observed in conjugates. Carboxy carrying MPcs have very poor electron transfer kinetics (both tetrasubstituted and low symmetry), but the presence of SWCNTs activates their catalysis. All electrochemical studies were done at pH 4. Cyclic voltammetry, rotating disk linear sweep voltammetry, chronoamperometry and EIS were used in the electrochemical characterization of 2-ME and the pesticides on poly-Ni(OH)TAPc and MPc-SWCNT modified glassy carbon electrodes (GCEs). High Tafel slopes were observed for the pesticides relative to 2-ME, an indication of the passivating nature of their oxidation products. However, conjugates showed very high resistances to passivation and were easily regenerated by shaking in methanol. Improved catalysis of the conjugates is also indicated by the high catalytic rate constants for the analytes, observed on these electrodes. Conjugates of low symmetry MPcs with SWCNTs gave the highest catalytic rate constants, confirming better catalysis on these electrode surfaces. The nature of SWCNT functionalization also affected catalysis, with amine functionalized SWCNTs inducing better catalytic properties into the MPcs than carboxylic acid terminated CNTs. The presence of amine functionalized SWCNTs activates the catalysis of non-catalytic carboxy-carrying MPcs and this is more pronounced in conjugates of tetrasubstituted MPcs relative to those of low symmetry Pcs. Ethylene amine (EA) functionalized SWCNTs reduced redox overpotentials of the MPcs more than the phenyl-amine (PA) functionalized counterparts. Poly-NiTAPc was successfully converted to poly-Ni(OH)TAPc through cyclisation in pH 4 buffer and showed very good catalytic properties towards diuron, relative to the former.
- Full Text:
- Date Issued: 2011
Characterization of stratified L-topological spaces by convergence of stratified L-filters
- Authors: Orpen, David Lisle
- Date: 2011
- Subjects: Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5402 , http://hdl.handle.net/10962/d1005216 , Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Description: For the case where L is an ecl-premonoid, we explore various characterizations of SL-topological spaces, in particular characterization in terms of a convergence function lim: FS L(X) ! LX. We find we have to introduce a new axiom , L on the lim function in order to completely describe SL-topological spaces, which is not required in the case where L is a frame. We generalize the classical Kowalski and Fischer axioms to the lattice context and examine their relationship to the convergence axioms. We define the category of stratified L-generalized convergence spaces, as a generalization of the classical convergence spaces and investigate conditions under which it contains the category of stratified L-topological spaces as a reflective subcategory. We investigate some subcategories of the category of stratified L-generalized convergence spaces obtained by generalizing various classical convergence axioms.
- Full Text:
- Date Issued: 2011
- Authors: Orpen, David Lisle
- Date: 2011
- Subjects: Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5402 , http://hdl.handle.net/10962/d1005216 , Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Description: For the case where L is an ecl-premonoid, we explore various characterizations of SL-topological spaces, in particular characterization in terms of a convergence function lim: FS L(X) ! LX. We find we have to introduce a new axiom , L on the lim function in order to completely describe SL-topological spaces, which is not required in the case where L is a frame. We generalize the classical Kowalski and Fischer axioms to the lattice context and examine their relationship to the convergence axioms. We define the category of stratified L-generalized convergence spaces, as a generalization of the classical convergence spaces and investigate conditions under which it contains the category of stratified L-topological spaces as a reflective subcategory. We investigate some subcategories of the category of stratified L-generalized convergence spaces obtained by generalizing various classical convergence axioms.
- Full Text:
- Date Issued: 2011
Characterization of village chicken health and management practices in the Amatola Basin of the Eastern Cape Province of South Afrrica
- Nyoni, Njongenhle Mhlanhlandlela Bernard
- Authors: Nyoni, Njongenhle Mhlanhlandlela Bernard
- Date: 2011
- Subjects: Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11804 , http://hdl.handle.net/10353/561 , Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Description: Characterization of village chicken phealth and management practices in the Amatola Basin of the Eastern Cape Province, South Africa By Njongenhle M. B. NYONI The majority of rural households in South Africa own village chickens which contribute significantly to their livelihoods. However, limited research has been conducted to characterize, understand and develop village chicken production in South Africa. This hinders the designing and implementation of village chicken-based developmental programmes that will benefit farmers in rural areas. Thus, it is imperative to initiate studies to describe village chicken production. This study was conducted to characterize village chicken production in Amatola Basin of the Eastern Cape Province of South Africa. Baseline information was gathered using a questionnaire survey of 81 identified from 7 out of 13 villages using snowball sampling technique. Consequently, 20 households were selected to participate in a monitoring study (from July 2010 to June 2011) through purposive sampling. Most (60%) chicken flocks were owned by women and mainly raised to meet household food requirements. Some (28.4%) farmers occasionally sold cocks and hens to neighbours, at an average price of R50 (USD7.55) per bird, as a way of culling their flocks and generating income. However, village chickens were mainly kept for food security rather than for their terminal benefit of cash. Although, all chicken flocks were produced under the scavenging feeding system, most (96%) flocks were provided with supplementary feed and drinking water. A majority (93.8%) of households also provided some form of shelter for their chickens. The mean cock to hen to chick ratio was 1:5:15. On average, iii each household owned 17 (±2 S.E.M.) chickens, and hens had 3.3 clutches per annum. Chicks hatched and chickens received as gifts represented the flock entries, while exits included mortality, consumption, sales and gifts or donations, in that order. Generally, both exits and entries were more pronounced in the summer season than in other seasons. Most (81.5%) farmers experienced chicken losses due to predation and health related problems. Parasitism ranked high amongst the village chicken health challenges. During monitoring, the endoprasites identified included nematodes, cestodes and protozoa. Coccidia were the most prevalent endoparasites. The chickens were also infested with a variety of ectoparasites namely: mites, lice, fleas and ticks. The sticktight flea Echidnophaga gallinacean was the most prevalent species. Although ectoparasite infestations were most pronounced in summer, almost all chickens harbored one or more of these parasites throughout the study period. The prevalence and intensity of parasite infestations were significantly (P<0.05) higher in the summer season compared to the other seasons. This was followed by the autumn, spring and winter seasons, respectively. The majority (77.5%) of farmers resorted to alternative remedies, mostly medicinal plants, for treating diseases and controlling parasites. Medicinal plants were used because they were locally available, cheap and perceived to be effective. Therefore, village chicken production in the rural Eastern Cape Province is characterised by several challenges which counter the significant role chickens play in the livelihood of rural households.
- Full Text:
- Date Issued: 2011
- Authors: Nyoni, Njongenhle Mhlanhlandlela Bernard
- Date: 2011
- Subjects: Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11804 , http://hdl.handle.net/10353/561 , Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Description: Characterization of village chicken phealth and management practices in the Amatola Basin of the Eastern Cape Province, South Africa By Njongenhle M. B. NYONI The majority of rural households in South Africa own village chickens which contribute significantly to their livelihoods. However, limited research has been conducted to characterize, understand and develop village chicken production in South Africa. This hinders the designing and implementation of village chicken-based developmental programmes that will benefit farmers in rural areas. Thus, it is imperative to initiate studies to describe village chicken production. This study was conducted to characterize village chicken production in Amatola Basin of the Eastern Cape Province of South Africa. Baseline information was gathered using a questionnaire survey of 81 identified from 7 out of 13 villages using snowball sampling technique. Consequently, 20 households were selected to participate in a monitoring study (from July 2010 to June 2011) through purposive sampling. Most (60%) chicken flocks were owned by women and mainly raised to meet household food requirements. Some (28.4%) farmers occasionally sold cocks and hens to neighbours, at an average price of R50 (USD7.55) per bird, as a way of culling their flocks and generating income. However, village chickens were mainly kept for food security rather than for their terminal benefit of cash. Although, all chicken flocks were produced under the scavenging feeding system, most (96%) flocks were provided with supplementary feed and drinking water. A majority (93.8%) of households also provided some form of shelter for their chickens. The mean cock to hen to chick ratio was 1:5:15. On average, iii each household owned 17 (±2 S.E.M.) chickens, and hens had 3.3 clutches per annum. Chicks hatched and chickens received as gifts represented the flock entries, while exits included mortality, consumption, sales and gifts or donations, in that order. Generally, both exits and entries were more pronounced in the summer season than in other seasons. Most (81.5%) farmers experienced chicken losses due to predation and health related problems. Parasitism ranked high amongst the village chicken health challenges. During monitoring, the endoprasites identified included nematodes, cestodes and protozoa. Coccidia were the most prevalent endoparasites. The chickens were also infested with a variety of ectoparasites namely: mites, lice, fleas and ticks. The sticktight flea Echidnophaga gallinacean was the most prevalent species. Although ectoparasite infestations were most pronounced in summer, almost all chickens harbored one or more of these parasites throughout the study period. The prevalence and intensity of parasite infestations were significantly (P<0.05) higher in the summer season compared to the other seasons. This was followed by the autumn, spring and winter seasons, respectively. The majority (77.5%) of farmers resorted to alternative remedies, mostly medicinal plants, for treating diseases and controlling parasites. Medicinal plants were used because they were locally available, cheap and perceived to be effective. Therefore, village chicken production in the rural Eastern Cape Province is characterised by several challenges which counter the significant role chickens play in the livelihood of rural households.
- Full Text:
- Date Issued: 2011
Childhood development and career development in eight year-old South African girls
- Van der Westhuyzen, Nicole Tamsin
- Authors: Van der Westhuyzen, Nicole Tamsin
- Date: 2011
- Subjects: Childhood development , Career development , Griffiths scales of mental development , Early childhood education -- Vocational guidance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9942 , http://hdl.handle.net/10948/d1012969
- Description: Although it is generally acknowledged that critical career-related concepts and attitudes are first formed in childhood, research has focused little attention on this developmental stage. Statements about children‘s career development as an integral dimension of human development date to the early 1950s, yet limited research has investigated this interrelationship. It is imperative to gain a greater understanding of childhood career development in order to better prepare children for their future. The overall purpose of this study is to explore the interrelationship of childhood development and childhood career development. An exploratory-descriptive quantitative research method was used. Thirty participants (all eight year-old girls from a middle class, English speaking background) were selected through non-probability purposive sampling. Data were gathered from the Griffiths Mental Development Scales – Extended Revised (GMDS-ER) and the Childhood Career Development Scale (CCDS) and analysed using descriptive and inferential statistics. The results indicated a correlation, although not statistically significant, between childhood development and childhood career development, thus indicating a weak positive correlation between the two variables. Statistically significant relationships were established between certain subscales of the GMDS-ER and CCDS, namely Language and Exploration, Eye-Hand Co-ordination and Key Figures, and Practical Reasoning and Planning. The results from this study, although not conclusive, are groundbreaking in this neglected area of research as they indicate an interrelationship between childhood development and childhood career development. This research is an initial step in investigating this interrelationship and it is the hope of the researcher that it will stimulate further research in this area.
- Full Text:
- Date Issued: 2011
- Authors: Van der Westhuyzen, Nicole Tamsin
- Date: 2011
- Subjects: Childhood development , Career development , Griffiths scales of mental development , Early childhood education -- Vocational guidance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9942 , http://hdl.handle.net/10948/d1012969
- Description: Although it is generally acknowledged that critical career-related concepts and attitudes are first formed in childhood, research has focused little attention on this developmental stage. Statements about children‘s career development as an integral dimension of human development date to the early 1950s, yet limited research has investigated this interrelationship. It is imperative to gain a greater understanding of childhood career development in order to better prepare children for their future. The overall purpose of this study is to explore the interrelationship of childhood development and childhood career development. An exploratory-descriptive quantitative research method was used. Thirty participants (all eight year-old girls from a middle class, English speaking background) were selected through non-probability purposive sampling. Data were gathered from the Griffiths Mental Development Scales – Extended Revised (GMDS-ER) and the Childhood Career Development Scale (CCDS) and analysed using descriptive and inferential statistics. The results indicated a correlation, although not statistically significant, between childhood development and childhood career development, thus indicating a weak positive correlation between the two variables. Statistically significant relationships were established between certain subscales of the GMDS-ER and CCDS, namely Language and Exploration, Eye-Hand Co-ordination and Key Figures, and Practical Reasoning and Planning. The results from this study, although not conclusive, are groundbreaking in this neglected area of research as they indicate an interrelationship between childhood development and childhood career development. This research is an initial step in investigating this interrelationship and it is the hope of the researcher that it will stimulate further research in this area.
- Full Text:
- Date Issued: 2011
Climate change adaptation and economic valuation of local pig genetic resources in communal production systems of South Africa
- Authors: Madzimure, James
- Date: 2011
- Subjects: Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11805 , http://hdl.handle.net/10353/427 , Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Description: The broad objective of the study was to determine the economic value of local pigs in marketand subsistence-oriented production systems in communal areas of Southern Africa. Data were collected from 288 households to investigate farmer perceptions, effects on pig production and handling of disease outbreaks such as classical swine fever (CSF) in market- and subsistenceoriented production systems. The utilisation of local pigs in these market- and subsistenceoriented production systems in improving people‟s welfare was evaluated. Climate change was identified by farmers in these production systems as a major constraint to pig production hence an experiment was carried out in the hottest season to determine diurnal heat-related physiological and behavioural responses in Large White (LW) and South African local pigs. The same genotypes were used to determine effects of diurnal heat-related stress on their growth performance. Choice experiment was done to determine farmer preferences for local pig traits and implicit prices for these traits in CSF-affected and unaffected areas that were under subsistence- and market-oriented production systems. In this experiment, the importance of heat tolerance was assessed relative to other productive and climate change adaptation traits. Significantly more pigs were culled in the CSF-affected areas that were market-oriented (8.0 ± 1.76) than subsistence-oriented (4.1 ± 1.00) production system. The risk of parasites and disease challenges was high in subsistence-oriented production system and coastal areas. In both production systems, CSF was perceived as destructive since the culling of pigs affected pork availability and income generation. The high risk of disease outbreaks and threat of climate change caused farmers in subsistence-oriented production system to select local pigs for their adaptive traits while those in the market-oriented production system focused on productive imported pigs. Farmers (83 %) indicated that they wanted pig genotypes that were adapted to climate change effects such as hot conditions. Local pigs were found to have superior heat tolerance over LW pigs (P < 0.05) in terms of lower heart rate and skin surface temperature. Frequency per day and duration for behavioural heat loss activities such as wallowing, sleeping in a prostrate posture and sprawling in slurry were also lower (P < 0.05) for local than LW pigs. The superiority of heat tolerance of local over LW pigs was further confirmed by their uncompromised growth performance under high diurnal temperatures. The Pearson‟s product moment correlation coefficient between temperature and feed conversion ratio for LW pigs was strongly positive (r = 0.50; P < 0.001) unlike the weak and positive correlation for local pigs (r = 0.20; P < 0.05). There was a quadratic relationship between temperature and average daily gain (ADG) for both pig genotypes. The regression coefficients for ADG were higher (P < 0.001) for LW than local pigs. It was concluded that at high ambient temperatures, performance of local pigs was less compromised than for LW pigs. Although local pigs were found to be heat tolerant, results of choice experiment showed that this trait was not selected for relative to other traits. Keeping pigs that required bought-in feeds, fell sick often and produced low pork quality (eating quality based on farmer perceptions) negatively affected farmers‟ livelihoods more in subsistence- than market-oriented production system. Farmers in market-oriented production system derived more benefit from productive traits such as heavier slaughter weights and large litter size than subsistence-oriented farmers. Under the subsistence-oriented production system, farmers in CSF-affected areas placed high prices on adaptive traits than the unaffected areas. Subsistence-oriented farmers who were affected by CSF wanted a total compensation price of R10 944.00 (USD1563.43) for keeping a pig genotype with unfavourable traits when compared to R4235.00 (USD605.00) for their CSF-unaffected counterparts. Implicit prices for traits could not be determined for market-oriented production system. It was concluded that farmers in CSFaffected areas placed high economic values on pig traits than farmers from the CSF-unaffected areas. The findings suggest that adapted local pigs can be promoted in subsistence-oriented production systems while productive imported pigs and their crosses with local pigs can be kept in market-oriented production systems.
- Full Text:
- Date Issued: 2011
- Authors: Madzimure, James
- Date: 2011
- Subjects: Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11805 , http://hdl.handle.net/10353/427 , Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Description: The broad objective of the study was to determine the economic value of local pigs in marketand subsistence-oriented production systems in communal areas of Southern Africa. Data were collected from 288 households to investigate farmer perceptions, effects on pig production and handling of disease outbreaks such as classical swine fever (CSF) in market- and subsistenceoriented production systems. The utilisation of local pigs in these market- and subsistenceoriented production systems in improving people‟s welfare was evaluated. Climate change was identified by farmers in these production systems as a major constraint to pig production hence an experiment was carried out in the hottest season to determine diurnal heat-related physiological and behavioural responses in Large White (LW) and South African local pigs. The same genotypes were used to determine effects of diurnal heat-related stress on their growth performance. Choice experiment was done to determine farmer preferences for local pig traits and implicit prices for these traits in CSF-affected and unaffected areas that were under subsistence- and market-oriented production systems. In this experiment, the importance of heat tolerance was assessed relative to other productive and climate change adaptation traits. Significantly more pigs were culled in the CSF-affected areas that were market-oriented (8.0 ± 1.76) than subsistence-oriented (4.1 ± 1.00) production system. The risk of parasites and disease challenges was high in subsistence-oriented production system and coastal areas. In both production systems, CSF was perceived as destructive since the culling of pigs affected pork availability and income generation. The high risk of disease outbreaks and threat of climate change caused farmers in subsistence-oriented production system to select local pigs for their adaptive traits while those in the market-oriented production system focused on productive imported pigs. Farmers (83 %) indicated that they wanted pig genotypes that were adapted to climate change effects such as hot conditions. Local pigs were found to have superior heat tolerance over LW pigs (P < 0.05) in terms of lower heart rate and skin surface temperature. Frequency per day and duration for behavioural heat loss activities such as wallowing, sleeping in a prostrate posture and sprawling in slurry were also lower (P < 0.05) for local than LW pigs. The superiority of heat tolerance of local over LW pigs was further confirmed by their uncompromised growth performance under high diurnal temperatures. The Pearson‟s product moment correlation coefficient between temperature and feed conversion ratio for LW pigs was strongly positive (r = 0.50; P < 0.001) unlike the weak and positive correlation for local pigs (r = 0.20; P < 0.05). There was a quadratic relationship between temperature and average daily gain (ADG) for both pig genotypes. The regression coefficients for ADG were higher (P < 0.001) for LW than local pigs. It was concluded that at high ambient temperatures, performance of local pigs was less compromised than for LW pigs. Although local pigs were found to be heat tolerant, results of choice experiment showed that this trait was not selected for relative to other traits. Keeping pigs that required bought-in feeds, fell sick often and produced low pork quality (eating quality based on farmer perceptions) negatively affected farmers‟ livelihoods more in subsistence- than market-oriented production system. Farmers in market-oriented production system derived more benefit from productive traits such as heavier slaughter weights and large litter size than subsistence-oriented farmers. Under the subsistence-oriented production system, farmers in CSF-affected areas placed high prices on adaptive traits than the unaffected areas. Subsistence-oriented farmers who were affected by CSF wanted a total compensation price of R10 944.00 (USD1563.43) for keeping a pig genotype with unfavourable traits when compared to R4235.00 (USD605.00) for their CSF-unaffected counterparts. Implicit prices for traits could not be determined for market-oriented production system. It was concluded that farmers in CSFaffected areas placed high economic values on pig traits than farmers from the CSF-unaffected areas. The findings suggest that adapted local pigs can be promoted in subsistence-oriented production systems while productive imported pigs and their crosses with local pigs can be kept in market-oriented production systems.
- Full Text:
- Date Issued: 2011
Co-utilisation of microalgae for wastewater treatment and the production of animal feed supplements
- Authors: Johnson, Hailey E
- Date: 2011
- Subjects: Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3940 , http://hdl.handle.net/10962/d1003999 , Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Description: Microalgae have a variety of commercial applications, the oldest of which include utilisation as a food source and for use in wastewater treatment. These applications, however, are seldom combined due to toxicity concerns, for ethical reasons, and generally the requirement for cultivation of a single algae species for use as a feed supplement. These problems might be negated if a “safer” wastewater such as that from agricultural and/or commercial food production facilities were to be utilised and if a stable algae population can be maintained. In this investigation preliminary studies were carried out using an Integrated Algae Pond System (IAPS) for domestic wastewater treatment to determine the species composition in the associated High Rate Algae Ponds (HRAPs). The effect of different modes of operation, continuous versus batch, on nutrient removal, productivity and species composition was also investigated. Furthermore, indigenous species in the HRAP were isolated and molecularly identified as, Chlorella, Micractinium, Scenedesmus and Pediastrum. Additionally, the effect of the nor amino acid, 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) and its Cu-chelated derivative, on the growth and biochemical composition of Chlorella, Micractinium, Scenedesmus, Pediastrum and Spirulina was investigated. Species composition in the HRAP was stable under continuous operation with Micractinium dominating > 90% of the algae population. Under batch operation the population dynamic shifted; Chlorella outcompeted Micractinium possibly due to nutrient depletion and selective grazing pressures caused by proliferation of Daphnia. Higher species diversity was observed during batch mode as slower growing algae were able to establish in the HRAP. Nutrient removal efficiency and biomass productivity was higher in continuous mode, however lower nutrient levels were obtained in batch operation. HMTBA did not significantly affect growth rate, however treatment with 10 mg.L-1 resulted in slightly increased growth rate in Micractinium and increased final biomass concentrations in Chlorella, Micractinium and Spirulina (although this was not statistically significant for Micractinium and Spirulina), which are known mixotrophic species. Algae treated with Cu-HMTBA, showed reduced final biomass concentration with 10 mg.L-1, caused by Cu toxicity. Biochemical composition of the algae was species-specific and differed through the growth cycle, with high protein observed during early growth and high carbohydrate during late growth/early stationary phase. Additionally, 0.1 mg.L-1 HMTBA and Cu-HMTBA significantly reduced protein content in Chlorella, Micractinium, Scenedesmus and Pediastrum. In conclusion, operation of the HRAP in continuous culture provided suitable wastewater treatment with high productivity of an ideal species, Micractinium, for use in animal feed supplementation. This species had 40% protein content during growth (higher than the other species tested) and dominated the HRAP at > 90% of the algae population during continuous mode. Addition of HMTBA (> 1 mg.L-1) to algae cultivation systems and those treating wastewater, has the potential to improve productivity and the value of the biomass by enhancing protein content. Overall, the co-utilisation of microalgae for wastewater treatment and the generation of a biomass rich in protein, for incorporation into formulated animal feed supplements, represents a closed ecosystem which conserves nutrients and regenerates a most valuable resource, water.
- Full Text:
- Date Issued: 2011
- Authors: Johnson, Hailey E
- Date: 2011
- Subjects: Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3940 , http://hdl.handle.net/10962/d1003999 , Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Description: Microalgae have a variety of commercial applications, the oldest of which include utilisation as a food source and for use in wastewater treatment. These applications, however, are seldom combined due to toxicity concerns, for ethical reasons, and generally the requirement for cultivation of a single algae species for use as a feed supplement. These problems might be negated if a “safer” wastewater such as that from agricultural and/or commercial food production facilities were to be utilised and if a stable algae population can be maintained. In this investigation preliminary studies were carried out using an Integrated Algae Pond System (IAPS) for domestic wastewater treatment to determine the species composition in the associated High Rate Algae Ponds (HRAPs). The effect of different modes of operation, continuous versus batch, on nutrient removal, productivity and species composition was also investigated. Furthermore, indigenous species in the HRAP were isolated and molecularly identified as, Chlorella, Micractinium, Scenedesmus and Pediastrum. Additionally, the effect of the nor amino acid, 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) and its Cu-chelated derivative, on the growth and biochemical composition of Chlorella, Micractinium, Scenedesmus, Pediastrum and Spirulina was investigated. Species composition in the HRAP was stable under continuous operation with Micractinium dominating > 90% of the algae population. Under batch operation the population dynamic shifted; Chlorella outcompeted Micractinium possibly due to nutrient depletion and selective grazing pressures caused by proliferation of Daphnia. Higher species diversity was observed during batch mode as slower growing algae were able to establish in the HRAP. Nutrient removal efficiency and biomass productivity was higher in continuous mode, however lower nutrient levels were obtained in batch operation. HMTBA did not significantly affect growth rate, however treatment with 10 mg.L-1 resulted in slightly increased growth rate in Micractinium and increased final biomass concentrations in Chlorella, Micractinium and Spirulina (although this was not statistically significant for Micractinium and Spirulina), which are known mixotrophic species. Algae treated with Cu-HMTBA, showed reduced final biomass concentration with 10 mg.L-1, caused by Cu toxicity. Biochemical composition of the algae was species-specific and differed through the growth cycle, with high protein observed during early growth and high carbohydrate during late growth/early stationary phase. Additionally, 0.1 mg.L-1 HMTBA and Cu-HMTBA significantly reduced protein content in Chlorella, Micractinium, Scenedesmus and Pediastrum. In conclusion, operation of the HRAP in continuous culture provided suitable wastewater treatment with high productivity of an ideal species, Micractinium, for use in animal feed supplementation. This species had 40% protein content during growth (higher than the other species tested) and dominated the HRAP at > 90% of the algae population during continuous mode. Addition of HMTBA (> 1 mg.L-1) to algae cultivation systems and those treating wastewater, has the potential to improve productivity and the value of the biomass by enhancing protein content. Overall, the co-utilisation of microalgae for wastewater treatment and the generation of a biomass rich in protein, for incorporation into formulated animal feed supplements, represents a closed ecosystem which conserves nutrients and regenerates a most valuable resource, water.
- Full Text:
- Date Issued: 2011